[Federal Register Volume 64, Number 211 (Tuesday, November 2, 1999)]
[Proposed Rules]
[Pages 59246-59378]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-27741]
[[Page 59245]]
_______________________________________________________________________
Part II
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 141 and 142
National Primary Drinking Water Regulations; Radon-222; Proposed Rule
Federal Register / Vol. 64, No. 211 / Tuesday, November 2, 1999 /
Proposed Rules
[[Page 59246]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 141 and 142
[WH-FRL-6462-8]
RIN 2040-AA94
National Primary Drinking Water Regulations; Radon-222
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of proposed rulemaking.
-----------------------------------------------------------------------
SUMMARY: In this action, the Environmental Protection Agency (EPA) is
proposing a multimedia approach to reducing radon risks in indoor air
(where the problem is greatest), while protecting public health from
the highest levels of radon in drinking water. Most radon enters indoor
air from soil under homes and other buildings. Only approximately 1-2
percent comes from drinking water. The Agency is proposing a Maximum
Contaminant Level Goal (MCLG) and National Primary Drinking Water
Regulations (NPDWR) for radon-222 in public water supplies. Under the
framework set forth in the 1996 amendments to the SDWA, EPA is also
proposing an alternative maximum contaminant level (AMCL) and
requirements for multimedia mitigation (MMM) programs to address radon
in indoor air. Public water systems (PWS) are defined in the Safe
Drinking Water Act (SDWA). This proposed rule applies to community
water systems (CWS), a subset of PWSs. Under the proposed rule, CWSs
may comply with the AMCL if they are in States that develop an EPA-
approved MMM program or, in the absence of a State program, develop a
State-approved CWS MMM program. This approach is intended to encourage
States, Tribes, and CWSs to reduce the health risk of radon in the most
cost-effective way. The Agency is also proposing a maximum contaminant
level (MCL) for radon-222, to apply to CWSs in non-MMM States that
choose not to implement a CWS MMM program. The proposal also includes
monitoring, reporting, public notification, and consumer confidence
report requirements for radon-222 in drinking water.
DATES: EPA must receive public comments, in writing, on the proposed
regulations by January 3, 2000.
ADDRESSES: You may send written comments to the Radon-222, W-99-08
Comments Clerk, Water Docket (MC-4101); U.S. Environmental Protection
Agency; 401 M Street, SW., Washington, DC 20460. Comments may be hand-
delivered to the Water Docket, U.S. Environmental Protection Agency;
401 M Street, SW., East Tower Basement, Washington, DC 20460. Comments
may be submitted electronically to owdocket@epamail.epa.gov. Electronic
comments must be submitted as an ASCII, WP6.1, or WP8 file avoiding the
use of special characters and any form of encryption. Electronic
comments must be identified by the docket number W-99-08. Comments and
data will also be accepted on disks in WP6.1, WP8, or ASCII format.
Electronic comments on this action may be filed online at many Federal
Depository libraries.
Please submit a copy of any references cited in your comments.
Facsimiles (faxes) cannot be accepted. EPA would appreciate one
original and three copies of your comments and enclosures (including
any references). Commenters who would like EPA to acknowledge receipt
of their comments should include a self-addressed, stamped envelope.
The proposed rule and supporting documents, including public
comments, are available for review in the Water Docket at the address
listed previously. The Docket also has several of the key supporting
documents electronically available as PDF files. For information on how
to access Docket materials, please call (202) 260-3027 between 9 a.m.
and 3:30 p.m. Eastern Time, Monday through Friday.
FOR FURTHER INFORMATION CONTACT: For general information on radon in
drinking water, contact the Safe Drinking Water Hotline, phone (800)
426-4791. The Safe Drinking Water Hotline is open Monday through
Friday, excluding Federal holidays, from 9 a.m. to 5:30 p.m. Eastern
Time. For technical inquiries regarding the proposed regulations,
contact Sylvia Malm, Office of Ground Water and Drinking Water, U.S.
Environmental Protection Agency (mailcode 4607), 401 M Street, SW,
Washington DC, 20460. Phone: (202) 260-0417. E-mail:
malm.sylvia@epa.gov. For inquiries regarding the proposed multimedia
mitigation program, contact Anita Schmidt, Office of Radiation and
Indoor Air, U.S. Environmental Protection Agency, (mailcode 6609J), 401
M Street, S.W, Washington, DC, 20460. Phone: (202) 564-9452. E-mail:
schmidt.anita@epa.gov. For general information on radon in indoor air,
contact the Radon Hotline at 1-800-SOS-RADON (1-800-767-7236).
SUPPLEMENTARY INFORMATION:
Potentially Regulated Entities
Potentially regulated entities include community water systems
using ground water or mixed ground and surface water.
The following table lists potentially regulated entities. This
table is not intended to be exhaustive, but rather provides a guide for
readers regarding entities likely to be regulated by this action. This
table lists the types of entities that EPA is now aware of that could
potentially be regulated by this action. Other entities not listed in
the table could also be regulated. To determine whether your
organization is affected by this action, you should carefully examine
the proposed applicability criteria in section 40 CFR parts
141.20(b)(1) and Section IV of the preamble. If you have questions
regarding the applicability of this action to a particular entity,
consult Sylvia Malm who is listed in the preceding FOR FURTHER
INFORMATION CONTACT section.
------------------------------------------------------------------------
Examples of potentially
Category regulated entities
------------------------------------------------------------------------
Industry.................................. Privately owned/operated
community water supply
systems using ground water
or mixed ground water and
surface water.
State, Tribal, and Local Government....... State, Tribal, or local
government-owned/operated
water supply systems using
ground water or mixed
ground water and surface
water.
Federal Government........................ Federally owned/operated
community water supply
systems using ground water
or mixed ground water and
surface water.
------------------------------------------------------------------------
Abbreviations Used in This Proposal
AMCL: Alternative Maximum Contaminant Level
BAT: Best Available Technology
BEIR: Committee on the Biological Effects of Ionizing Radiation. The
Committee on Health Risks of Exposure on Radon that conducted the
National Research Council Biological Effects of Ionizing Radiation
(BEIR) VI Study (NAS 1999a). The committee is formed by the Radiation
Effect Research/Commission on Life Sciences/National Research Council/
National Academy of Sciences.
CFR: Code of Federal Regulations
CWS: Community Water System
EF: Equilibrium Factor
EPA: U.S. Environmental Protection Agency
FR: Federal Register
GAC: Granular Activated Carbon
[[Page 59247]]
HRRCA: Health Risk Reduction and Cost Analysis
IOC: Inorganic Contaminant
LSC: Liquid Scintillation Counting
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level Goal
MMM: Multimedia Mitigation
NAS: National Academy of Sciences
NAS Radon in Drinking Water Committee: The Committee on Risk Assessment
of Exposure to Radon of the Drinking Water that conducted the National
Research Council Risk Assessment of Radon in Drinking Water Study (NAS
1999b). The committee is formed by the Board of Radiation Effect
Research of the Commission on Life Sciences of the National Research
Council, National Academy of Sciences.
NELAC: National Environmental Laboratory Accreditation Conference
NIST: National Institute of Standards and Technology
NIRS: National Inorganics and Radionuclides Survey
NPDWR: National Primary Drinking Water Regulation
NPRM: Notice of Proposed Rulemaking
NTNC: Non-Transient, Non-Community
OGWDW: Office of Ground Water and Drinking Water
OMB: Office of Management and Budget
PBMS: Performance-Based Measurement System
PE: Performance Evaluation
PT: Proficiency Testing
POE: Point-of-Entry
POU: Point-of-Use
PRA: Paperwork Reduction Act
PWS: Public Water System
pCi/L: Picocuries per Liter
RFA: Regulatory Flexibility Act
SAB: Science Advisory Board
SBA: Small Business Administration
SBO: Small Business Ombudsman
SBREFA: Small Business Regulatory Enforcement and Fairness Act
SDWA: Safe Drinking Water Act
SDWIS: Safe Drinking Water Information System
SIRG: State Indoor Radon Grant
SSCT: Small Systems Compliance Technology
SSVT: Small Systems Variance Technology
SMF: Standardized Monitoring Framework
UMRA: Unfunded Mandates Reform Act
URTH: Unreasonable Risks to Health
WL: Working Level
WLM: Working Level Month
Table of Contents
I. Summary: What Does Today's Proposed Rulemaking Mean for My Water
System?
A. Why is EPA Proposing to Regulate Radon in Drinking Water?
B. What is Radon?
C. What are the Health Concerns from Radon in Air and Water?
D. Does this Regulation Apply to My Water System?
E. How Will this Regulation Protect Public Health?
F. How Will the Multimedia Mitigation (MMM) Program Work?
G. What are the Proposed Limits for Radon in Drinking Water?
H. What is the Proposed Best Available Technology (BAT) for
Treating Radon in Drinking Water?
I. What Analytical Methods are Recommended?
J. Where and How Often Must I Test My Water for Radon?
K. May I Use Point-of-Use (POU) Devices, Point-of-Entry (POE)
Devices, or Bottled Water to Comply with this Regulation?
L. May I Get More Time or Use a Cheaper Treatment? Variances and
Exemptions
M. What are State Primacy, Record Keeping, and Reporting
Requirements?
N. How are Tribes Treated in this Proposal?
Statutory Requirements and Regulatory History
II. What Does the Safe Drinking Water Act Require the EPA to Do When
Regulating Radon in Drinking Water?
A. Withdraw the 1991 Proposed Regulation for Radon
B. Arrange for a National Academy of Sciences Risk Assessment.
C. Set an MCLG, MCL, and BAT for Radon-222
D. Set an Alternative MCL (AMCL) and Develop Multimedia
Mitigation (MMM) Program Plan Criteria
E. Evaluate Multimedia Mitigation Programs Every Five Years
III. What Actions Has EPA Taken on Radon in Drinking Water Prior to
This Proposal?
A. Regulatory Actions Prior to 1991
B. The 1991 NPRM
C. 1994 Report to Congress: Multimedia Risk and Cost Assessment
of Radon
D. 1997 Withdrawal of the 1991 NPRM for Radon-222
E. 1998 SBREFA Small Business Advocacy Review Panel for Radon
F. 1999 HRRCA for Radon in Drinking Water
Requirements
IV. To Which Water Systems Does this Regulation Apply?
V. What is the Proposed Maximum Contaminant Level Goal (MCLG) for
Radon?
A. Approach to Setting the MCLG
B. MCLG for Radon in Drinking Water
VI. What Must a State or Community Water System Have In Its
Multimedia Mitigation Program Plan?
A. What are the Criteria?
B. Why Will MMM Programs Get Risk Reduction Equal or Greater
Than Compliance with the MCL?
C. Implementation of an MMM Program in Non-Primacy States
D. Implementation of the MMM Program in Indian Country
E. CWS Role in State MMM Programs
F. Local CWS MMM Programs in Non-MMM States and State Role in
Approval of CWS MMM Program Plans
G. CWS Role in Communicating to Customers
H. How Did EPA Develop These Criteria?
I. Background on the Existing EPA and State Indoor Radon
Programs
VII. What are the Requirements for Addressing Radon in Water and
Radon in Air? MCL, AMCL and MMM
A. Requirements for Small Systems Serving 10,000 People or Less
B. Requirements for Large Systems Serving More Than 10,000
People
C. State Role in Approval of CWS MMM Program Plans
D. Background on Selection of MCL and AMCL
E. Compliance Dates
VIII. What are the Requirements for Testing for and Treating Radon
in Drinking Water?
A. Best Available Technologies (BATs), Small Systems Compliance
Technologies (SSCTs), and Associated Costs
B. Analytical Methods
C. Laboratory Approval and Certification
D. Performance-Based Measurement System (PBMS)
E. Proposed Monitoring and Compliance Requirements for Radon
IX. State Implementation
A. Special State Primacy Requirements
B. State Record Keeping Requirements
C. State Reporting Requirements
D. Variances and Exemptions
E. Withdrawing Approval of a State MMM Program
X. What Do I Need to Tell My Customers? Public Information
Requirements
A. Public Notification
B. Consumer Confidence Report
Risk Assessment and Occurrence
XI. What is EPA's Estimate of the Levels of Radon in Drinking Water?
A. General Patterns of Radon Occurrence
B. Past Studies of Radon Levels in Drinking Water
C. EPA's Most Recent Studies of Radon Levels in Ground Water
D. Populations Exposed to Radon in Drinking Water
XII. What Are the Risks of Radon in Drinking Water and Air?
A. Basis for Health Concern
B. Previous EPA Risk Assessment of Radon in Drinking Water
C. NAS Risk Assessment of Radon in Drinking Water
D. Estimated Individual and Population Risks
E. Assessment by National Academy of Sciences: Multimedia
Approach to Risk Reduction
Economics and Impacts Analysis
XIII. What is the EPA's Estimate of National Economic Impacts and
Benefits?
A. Safe Drinking Water Act (SDWA) Requirements for the HRRCA
B. Regulatory Impact Analysis and Revised Health Risk Reduction
and Cost Analysis (HRRCA) for Radon
[[Page 59248]]
C. Baseline Analysis
D. Benefits Analysis
E. Cost Analysis
F. Economic Impact Analysis
G. Weighing the Benefits and Costs
H. Response to Significant Public Comments on the February 1999
HRRCA
XIV. Administrative Requirements
A. Executive Order 12866: Regulatory Planning and Review
B. Regulatory Flexibility Act (RFA)
C. Unfunded Mandates Reform Act (UMRA)
D. Paperwork Reduction Act (PRA)
E. National Technology Transfer and Advancement Act (NTTAA)
F. Executive Order 12898: Environmental Justice
G. Executive Order 13045: Protection of Children from
Environmental Health Risks and Safety Risks
H. Executive Order on Federalism
I. Executive Order 13084: Consultation and Coordination with
Indian Tribal Governments
J. Request for Comments on Use of Plain Language
Stakeholder Involvement
XV. How has the EPA Provided Information to Stakeholders in
Development of this NPRM?
A. Office of Ground Water and Drinking Water Website
B. Public Meetings
C. Small Entity Outreach
D. Environmental Justice Initiatives
E. AWWA Radon Technical Work Group
Background
XVI. How Does EPA Develop Regulations to Protect Drinking Water?
A. Setting Maximum Contaminant Level Goal and Maximum
Contaminant Level
B. Identifying Best Available Treatment Technology
C. Identifying Affordable Treatment Technologies for Small
Systems
D. Requirements for Monitoring, Quality Control, and Record
Keeping
E. Requirements for Water Systems to Notify Customers of Test
Results if Not in Compliance
F. Approval of State Drinking Water Programs to Enforce Federal
Regulations
XVII. Important Technical Terms
XVIII. References
Appendix I to the Preamble: What are the Major Public Comments on the
1991 NPRM and How has the EPA Addressed Them in this Proposal?
A. General Issues
B. Statutory Authority and Requirements
C. Radon Occurrence
D. Radon Exposure and Health Effects
E. Maximum Contaminant Level
F. Analytical Methods
G. Treatment Technologies and Cost
H. Compliance Monitoring
I. Summary: What Does Today's Proposed Rulemaking Mean for My Water
System?
A. Why Is EPA Proposing To Regulate Radon in Drinking Water?
The proposed National Primary Drinking Water Regulation (NPDWR) for
radon in drinking water is based on a multimedia approach designed to
achieve greater risk reduction by addressing radon risks in indoor air,
with public water systems providing protection from the highest levels
of radon in their ground water supplies. The framework for this
proposal is set out in the Safe Drinking Water Act as amended in 1996
(SDWA), which provides for a multimedia approach for addressing the
public health risks from radon in drinking water and radon in indoor
air from soil. This statutory-based framework reflects the
characteristics uniquely specific to radon among drinking water
contaminants: that the relative cost-effectiveness of reducing risk
from exposure to this contaminant is substantially greater for a non-
drinking water source of exposure--indoor air--than it is from drinking
water. Accordingly, SDWA directs the Environmental Protection Agency
(EPA) to promulgate a maximum contaminant level (MCL) for radon in
drinking water, but also to make available a higher alternative maximum
contaminant level (AMCL) accompanied by a multimedia mitigation (MMM)
program to address radon risks in indoor air. Further, in setting the
MCL, EPA is to take into account the costs and benefits of programs
that control radon in indoor air (SDWA 1412(b)(13)(E)).
B. What Is Radon?
Radon's Physical Properties
Throughout this preamble, ``radon'' refers to the specific isotope
radon-222. Radon is a naturally occurring gas formed from the
radioactive decay of uranium-238. Low concentrations of uranium and its
other decay products, specifically radium-226, occur widely in the
earth's crust, and thus radon is continually being generated, even in
soils in which there is no man-made radioactive contamination. Radon is
colorless, odorless, tasteless, chemically inert, and radioactive. A
portion of the radon released through radioactive decay moves through
air or water-filled pores in the soil to the soil surface and enters
the air, while some remains below the surface and dissolves in ground
water (water that collects and flows under the ground's surface).
Because radon is a gas, when water that contains radon is exposed
to the air, the radon will tend to be released into the air. Therefore,
radon is usually present in only low amounts in rivers and lakes. If
ground water is supplied to a house, radon in the water will tend to be
released into the air of the house via various water uses. Thus
presence of radon in drinking water supplies leads to exposure via both
oral route (ingesting water containing radon) and inhalation route
(breathing air containing both radon and radon decay products released
from water used in the house such as for cooking and washing).
Radon itself also decays, emitting ionizing radiation in the form
of alpha particles, and transforms into decay products, or ``progeny''
radioisotopes. It has a half-life of about four days and decays into
short-lived progeny. Unlike radon, the progeny are not gases, and can
easily attach to and be transported by dust and other particles in air.
The decay of progeny continues until stable, non-radioactive progeny
are formed. At each step in the decay process, radiation is released.
C. What Are the Health Concerns From Radon in Air and Water?
National and international scientific organizations have concluded
that radon causes lung cancer in humans. The primary risk is lung
cancer from radon entering indoor air from soil under homes. Tap water
is a smaller source of radon in air; however, breathing radon released
to air from household water uses also increases the risk of lung
cancer, and consumption of drinking water containing radon presents a
smaller risk of internal organ cancers, primarily stomach cancer.
In most cases, radon in soil under homes is the biggest source of
exposure and radon from tap water will be a small source of radon in
indoor air.
The U.S. Surgeon General has warned that indoor radon (from soil)
is the second leading cause of lung cancer (USEPA 1988b). The National
Academy of Sciences (NAS 1999a) estimates that radon from soil causes
about 15,000 to 22,000 (using two different approaches) lung cancer
deaths each year in the U.S. If you smoke and your home has high indoor
radon levels, your risk of lung cancer is especially high. EPA and the
U.S. Surgeon General recommend testing all homes below the third floor.
The NAS report mandated by the 1996 SDWA identifies the same unit
risk associated with radon in drinking water compared with previous EPA
analyses. Based on the NAS risk assessment and an updated EPA
[[Page 59249]]
occurrence analysis, the Agency estimates that uncontrolled levels of
radon in public drinking water supplies cause 168 fatal cancers each
year in the U.S. However, radon in domestic drinking water generally
contributes a very small part (about 1-2 percent) of total radon
exposure from indoor air. The NAS estimated that about 89 percent of
the fatal cancers caused by radon in drinking water were due to lung
cancer from inhalation of radon released to indoor air, and about 11
percent were due to stomach cancer from consuming water containing
radon (NAS 1999b).
D. Does This Regulation Apply to My Water System?
The regulation for radon in drinking water and the multimedia
approach proposed in this action would apply to all community public
water systems (CWSs) that use ground water or mixed ground and surface
water. The proposed regulation would not apply to non-transient non-
community (NTNC) public water supplies, nor to transient public water
supplies.
E. How Will This Regulation Protect Public Health?
Given the much greater potential for risk reduction in indoor air
and years of experience with radon mitigation programs, EPA expects
that greater overall risk reduction will result from this proposal than
from an approach which solely addresses radon in public drinking water
supplies. The proposed regulation for radon in drinking water is
intended to promote a more cost-effective multimedia approach to reduce
radon risks, particularly for small systems with limited resources, and
to reduce the highest levels of radon in drinking water. This
determination to have a strong and effective multimedia radon program
to address radon in indoor air is consistent with the SDWA framework
for multimedia radon programs and the SDWA expectation that EPA would
give significant weight to the risk findings of the NAS report, which
confirm the health risks of radon in drinking water, and the much
greater risks from radon in indoor air arising from soil under homes.
F. How Will the Multimedia Mitigation (MMM) Program Work?
The multimedia mitigation (MMM) program is modeled on the National
Indoor Radon Program implemented by EPA, States and others. That
program has achieved substantial risk reduction through voluntary
public action since the release of the original ``A Citizen's Guide to
Radon'' in 1986 (USEPA 1986, 1992b) and the U.S. Surgeon General's
recommendation in 1988 that all homes be tested and elevated levels be
reduced. The program has been successful in achieving indoor radon risk
reduction through a variety of program strategies, which form the basis
for EPA's proposed multimedia mitigation program plan criteria. Based
on the estimated number of existing homes fixed and the number of new
homes built radon-resistant since the national program began in 1986,
EPA estimates that under existing Federal and State indoor radon
programs, a total of more than 2,500 lives will be saved through indoor
radon risk reduction efforts expected to take place through the year
2000. Every year the rate of lives saved increases as more existing
houses with elevated radon levels are fixed and as more new houses are
built radon-resistant. For the year 2000, EPA estimates that the rate
of radon-related lung cancer deaths that will be avoided from
mitigation of existing homes and from homes built radon-resistant (in
high radon areas) will be about 350 lives saved per year (USEPA 1999i).
The MMM/AMCL approach is intended to provide a more cost-effective
alternative to achieve radon risk reduction, by allowing States (or
community water systems) to address radon in indoor air from the soil
source, while reducing the highest levels of radon in drinking water.
It is EPA's expectation that most States will develop State-wide
multimedia mitigation programs as the most cost-effective approach.
Most of the States currently have indoor radon programs that are
addressing radon risk from soil, and can be used as the foundation for
development of MMM program plans. EPA expects that State indoor radon
programs will implement MMM programs under agreements with the State
drinking water programs. The regulatory expectation of community water
systems serving 10,000 persons or less is that they meet the
alternative maximum contaminant level (AMCL) and be associated with an
approved MMM program plan--either developed by the State and approved
by EPA or developed by the CWS and approved by the State. Tribal CWS
MMM programs, as well as those in States and Territories that do not
have drinking water primacy, will be approved by EPA. The same general
criteria for State MMM program plans would apply to CWSs in developing
local MMM programs in States that do not have such a program, albeit
with a local perspective on such criteria and commensurate with the
unique attributes of small CWSs. EPA expects that MMM program
strategies for CWSs will be less comprehensive than those of State MMM
programs, and will need to reflect the local character of the community
served by the CWS. Strong public participation in the development of
the CWS MMM program plans will help to ensure this, as well as
community support for the MMM program. Figures I.1 and I.2 provide a
conceptual model for the MCL, AMCL, and MMM programs for small and
large systems.
BILLING CODE 6560-50-P
[[Page 59250]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.000
[[Page 59251]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.001
BILLING CODE 6560-50-C
[[Page 59252]]
To meet the requirements of SDWA, the risk reduction benefits
expected to be achieved by MMM programs are to be equal to or greater
than risk reduction benefits that would be achieved by CWSs complying
with the MCL. Under SDWA, this means that if all States implemented MMM
programs they would be expected to result in about 62 cancer deaths
averted annually, equal to what would be achieved with universal
compliance with the MCL at 300 pCi/L. Unlike health risk reduction
benefits gained through water treatment, which remain constant from one
year to the next, the rate of health benefits from reducing indoor
radon is cumulative; that is, it steadily increases every year with
every additional existing home that is mitigated and with every new
home built radon-resistant. Therefore, MMM programs will use and build
on the indoor radon program framework to achieve ``equal or greater''
risk reduction, rather than focusing efforts on precisely quantifying
``equivalency'' to the much more limited risk reduction expected to
occur if community water systems complied with the MCL.
G. What Are the Proposed Limits for Radon in Drinking Water?
The proposed regulation provides that States may adopt State-wide
MMM programs and the alternative maximum contaminant level (AMCL) of
4000 pCi/L. This is the most effective approach for radon risk
reduction and the one EPA expects the majority of States to adopt. If a
State has an EPA-approved MMM program plan, CWSs in that State may
comply with the AMCL. In the absence of an approved State MMM program
plan the regulatory expectation for small CWSs (those serving 10,000 or
fewer) is that they comply with a level of 4000 pCi/L in drinking
water, and develop and implement a State-approved local MMM program
plan to reduce indoor radon risks arising from soil and rock under
homes and buildings. Small CWSs may also choose to comply with the MCL
of 300 pCi/L (and not develop a local MMM program.)
The AMCL/MMM approach is EPA's regulatory expectation for small
CWSs because an MMM program and compliance with the AMCL is a much more
cost-effective way to reduce radon risk than compliance with the
maximum contaminant level (MCL) of 300 pCi/L. (While EPA believes that
the MMM approach is preferable for small systems in a non-MMM State,
small CWSs may, at their discretion, choose the option of meeting the
MCL instead of developing a local MMM program). Large CWSs (serving a
population of more than 10,000) must either comply with the proposed
MCL or comply with the AMCL and implement a State-approved CWS MMM
program plan (in the absence of an approved State MMM program plan).
If a State has an approved MMM program plan, the standard for radon
in drinking water that the State would adopt in order to obtain primacy
would be 4000 pCi/L.
Under the proposed requirements, an MMM program plan must address
four criteria:
1. Public involvement in development of the MMM program plan
2. Quantitative goals for existing homes fixed and new homes built
radon-resistant
3. Strategies for achieving goals
4. Plan to track and report results
CWSs must monitor for radon in drinking water according to the
requirements described in Section VIII of this preamble, and report
their results to the State. If the State determines that the radon
level in a CWS is below 300 pCi/L, the system need only continue to
meet monitoring requirements and is not covered by the requirements
described in Section VI of this preamble, regarding MMM programs.
H. What Is the Proposed Best Available Technology (BAT) for Treating
Radon in Drinking Water?
Proposed BAT for Radon Under Section 1412 of the SDWA
High-performance aeration, as described in Section VIII.A of this
preamble, is the BAT for all systems. For systems serving 10,000
persons or fewer, the BAT is high-performance aeration and the Small
Systems Compliance Technologies, as described in Section VIII.A.
Proposed BAT for Radon Under Section 1415 of the SDWA
BAT for purposes of variances is the same as BAT under Section 1412
of the Act.
I. What Analytical Methods Are Recommended?
EPA is proposing Liquid Scintillation Counting (Standard Method
7500-Rn) and de-emanation (``Lucas Cell'') as the approved methods. The
Liquid Scintillation Counting method designated ``D 5072-92'' by the
American Society for Testing and Materials (ASTM) is being proposed as
an alternate method.
J. Where and How Often Must I Test My Water for Radon?
All CWSs that use ground water must monitor for radon. If your
system relies on ground water or uses ground water to supplement
surface water during low-flow periods, you must monitor for radon. If
you are required to monitor for radon you must collect samples for
analysis at each entry point to the distribution system, after
treatment and storage. Initially all CWSs using ground water must
monitor for radon at each entry point to the distribution system
quarterly for one year. (See Section VII.E for discussion of compliance
dates). If the results of analyses show that the average of all first
year samples at any sample site is above the MCL/AMCL, you must
continue monitoring quarterly at that sampling site until the average
of four consecutive quarterly samples is below the MCL/AMCL. If the
results of analyses show that the average of all first year samples at
each sample site is below the MCL/AMCL, you may reduce monitoring to
once a year at State discretion at each sample site. If the results
indicate that the average of the four quarterly samples are close to
the MCL/AMCL (as discussed next), the State may require you to continue
monitoring quarterly.
The State may allow you to reduce monitoring for radon to a
frequency of once every three-years, if the average from four
consecutive quarterly samples is less than \1/2\ the MCL/AMCL and the
State determines that your system is reliably and consistently below
the MCL/AMCL. However, if a sample collected while monitoring annually
or less frequently exceeds the radon MCL/AMCL, the monitoring frequency
must be increased to quarterly until the average of 4 consecutive
quarterly samples is less than the MCL/AMCL. The State may require the
collection of a confirmation sample(s) to verify the result of the
initial sample. In the case of reduced monitoring, if the analytical
results from any sampling point are found to exceed \1/2\ the MCL/AMCL,
the State may require you to collect a confirmation sample at the same
sampling point. The results of the initial sample and the confirmation
sample(s) will be averaged and the resulting average will be used to
determine compliance. States may, at their discretion, disregard
samples that have obvious sampling errors.
If, after initial monitoring, the State determines that it is
highly unlikely that radon levels in your system will be above the MCL/
AMCL, the State may grant a waiver reducing monitoring frequency to
once every nine years. In granting the waiver, the State must take into
consideration factors such as the geological area of the source water
and previous analytical results which demonstrate that radon levels do
not
[[Page 59253]]
occur above the MCL/AMCL. If you are granted a waiver, it remains in
effect for a nine year period.
If you monitor for radon after proposal of this rule, you may use
the data, at the State's discretion, toward satisfying the initial
sampling requirements for radon. Your monitoring program and the
methods used to analyze for radon must satisfy the regulations set out
in the proposal.
K. May I Use Point-of-Use (POU) Devices, Point-of-Entry (POE) Devices,
or Bottled Water To Comply With This Regulation?
POE aeration or granular activated carbon (GAC) would be allowable
for use to achieve compliance with MCLs. While these POE technologies
are not considered BAT for large systems, they are considered small
system compliance technologies (SSCTs), and thus may serve as BAT under
Sections 1412 and 1415 of the Act for systems serving 10,000 persons or
fewer. Since POU devices are used to treat water at a single tap, radon
will be released at unacceptable levels from the other non-treated
taps, including the shower head. For this reason, POU devices do not
adequately address radon risks and will not be allowed to be used for
compliance purposes. Likewise, although bottled water reduces ingestion
risk from radon, it does not reduce radon-related inhalation risks from
household water. For this reason, compliance determinations based on
bottled water consumption cannot be used.
L. May I Get More Time or Use a Cheaper Treatment? Variances and
Exemptions
Variances and Exemptions (Section 1415.a of the SDWA)
States and Tribes with primary enforcement responsibility
(``primacy'') may issue a variance under Section 1415(a)(1)(A) of the
Act to a CWS that cannot comply with an MCL because of source water
characteristics on condition that the system install the best available
technology. Under Section 1416 of the Act, primacy entities may exempt
a CWS from an NPDWR due to ``compelling factors'', subject to the
restrictions described in the Act. Primacy entities may require systems
to implement additional interim control measures such as installation
of additional centralized treatment or POE devices for each customer as
measures to reduce the health risk before granting a variance or
exemption. The primacy entity must find that the variance or exemption
will not pose an ``unreasonable risk to health'', as determined by the
State or other primacy entity. Guidance for estimating ``unreasonable
risk to health'' (URTH) values for contaminants, including radon, is
being developed by EPA and will result in an upcoming publication (a
draft of the guidance is expected in the Fall of 1999). Preliminary
information regarding URTH values may be found elsewhere (Orme-Zavaleta
1992, USEPA 1998f). States must require CWSs to provide POE devices or
other means, as appropriate to the risks present (i.e., no POU or
bottled water for volatile contaminants, such as radon), to reduce
exposure below unreasonable risk to health values before granting a
variance or exemption.
``Small Systems Variances'' (Section 1415(e) of the SDWA)
For NPDWRs proposed after the 1996 Amendments to the Act, EPA is
required to evaluate the affordability and technical feasibility of
treatment technologies for use as compliance technologies for small
systems. Three categories of small systems will be considered: those
serving: (1) 25-500, (2) 501-3,300, and (3) 3,301-10,000 persons. If
EPA determines that source water conditions exist for one or more small
water system size categories such that typical small systems within a
given category will not be able to afford and/or implement a technology
capable of achieving compliance, then EPA will designate applicable
``small systems variance technologies'' (SSVTs) capable of achieving
contaminant levels that are ``protective of public health''. Primacy
entities may issue small systems variances to eligible CWSs that
install and properly maintain a listed SSVT. For a small system to be
eligible for a small systems variance, the primacy entity must
determine that the system cannot afford to comply through installing
treatment, finding an alternate source of water, or restructuring/
consolidating.
EPA has determined that affordable and technically feasible
technologies exist for radon removal for all classes of small systems.
Under the 1996 SDWA, if EPA lists at least one small systems compliance
technology for a given system size category for all source water
qualities, then it may not list any small systems variance technologies
for that size category, i.e., small systems compliance technologies and
variance technologies are mutually exclusive. For this reason, no small
system will be eligible for a small systems variance for radon under
the SDWA (Section 1415(e)). Small systems may be eligible for general
variances (under Section 1415.a of the Act) and/or exemptions on a case
by case basis. It is also important to emphasize that the presumptive
regulatory expectation for small systems is an MMM program (in the
absence of a State MMM program) and compliance with the AMCL of 4000
pCi/L. Thus, for the vast majority of small systems (those with radon
levels below 4000 pCi/L), compliance with this proposed rule will not
involve any treatment of drinking water.
M. What Are State Primacy, Record Keeping, and Reporting Requirements?
The proposed Radon Rule requires States to adopt several regulatory
requirements, including public notification requirements, MCL/AMCL for
radon, and the requirements of Subpart R in the proposed rule. In
addition, States and eligible Indian tribes will be required to adopt
several special primacy requirements for the Radon Rule. The proposed
rule includes additional reporting requirements for MMM program plans.
The proposed rule also requires States to keep specific records in
accordance with existing regulations. These requirements are discussed
in more detail in Section IX of this preamble.
N. How Are Tribes Treated in This Proposal?
The proposal provides Tribes the option of seeking ``treatment in
the same manner as a State'' for the purposes of assuming enforcement
responsibility for a CWS program, and developing and implementing an
MMM program (see Section VI.C). If a Tribe chooses not to implement an
EPA-approved MMM program, any tribal CWS may develop an MMM plan for
EPA approval, under the same criteria described in Section VI.A.
Statutory Requirements and Regulatory History
II. What Does the Safe Drinking Water Act Require the EPA To Do
When Regulating Radon in Drinking Water?
The 1996 Amendments to the Safe Drinking Water Act (PL 104-182)
establish a new charter for public water systems, States, Tribes, and
EPA to protect the safety of drinking water supplies. (For an overview
of the general requirements for all drinking water regulations, see
Section XVI of this preamble). Among other mandates, Congress amended
Section 1412 of the SDWA to direct EPA to take the following actions
regarding radon in drinking water.
[[Page 59254]]
A. Withdraw the 1991 Proposed Regulation for Radon
Congress specified that EPA should withdraw the drinking water
standards proposed for radon in 1991 (see discussion in Section III.D).
B. Arrange for a National Academy of Sciences Risk Assessment
The amendments in Section 1412(b)(13)(B) require EPA to arrange for
the National Academy of Sciences (NAS) to conduct an independent risk
assessment for radon in drinking water and an assessment of the health
risk reduction benefits from various mitigation measures to reduce
radon in indoor air.
C. Set an MCLG, MCL, and BAT for Radon-222
Congress specified in Section 1412 (b)(13) that EPA should propose
a new MCLG and NPDWR for radon-222 by August, 1999. EPA is also
required to finalize the regulation by August, 2000. As a preliminary
step, EPA was required to publish a radon health risk reduction and
cost analysis (HRRCA) for possible radon MCLs for public comment by
February, 1999. As required by SDWA, this analysis addressed: (1)
Health risk reduction benefits that come directly from controlling
radon; (2) health risk reduction benefits likely to come from
reductions in contaminants that occur with radon; (3) costs; (4)
incremental costs and benefits associated with each MCL considered; (5)
effects on the general population and on groups within the general
population likely to be at greater risk; (6) any increased health risk
that may occur as the result of compliance; and (7) other relevant
factors, including the quality and extent of the information, the
uncertainties in the analysis, and factors with respect to the degree
and nature of the risk.
D. Set an Alternative MCL (AMCL) and Develop Multimedia Mitigation
(MMM) Program Plan Criteria
The amendments in Section 1412(b)(13)(F) introduced two new
elements into the radon in drinking water rule: (1) An Alternative
Maximum Contaminant Level (AMCL), and (2) radon multimedia mitigation
(MMM) programs. If the MCL established for radon in drinking water is
more stringent than necessary to reduce the contribution to radon in
indoor air from drinking water to a concentration that is equivalent to
the national average concentration of radon in outdoor air, EPA is
required to simultaneously establish an AMCL. The AMCL would be the
standard that would result in a contribution of radon from drinking
water to radon levels in indoor air equivalent to the national average
concentration of radon in outdoor air. If an AMCL is established, EPA
is to publish criteria for State multimedia mitigation (MMM) programs
to reduce radon levels in indoor air. Section VI of this preamble
describes what a State or public water system must have in their
multimedia mitigation program plan.
E. Evaluate Multimedia Mitigation Programs Every Five Years
Once the MMM programs are established, EPA must re-evaluate them no
less than every five years (Section 1412(b)(13)(G)). EPA may withdraw
approval of programs that are not expected to continue to meet the
requirement of achieving equal or greater risk reduction.
III. What Actions Has EPA Taken on Radon in Drinking Water Prior to
This Proposal?
A. Regulatory Actions Prior to 1991
Section 1412 of the SDWA, as amended in 1986, required the EPA to
publish Maximum Contaminant Level Goals (MCLGs) and to promulgate
NPDWRs for contaminants that may cause an adverse effect on human
health and that are known or anticipated to occur in public water
supplies. On September 30, 1986, EPA published an advance notice of
proposed rulemaking (ANPRM) (51 FR 34836) concerning radon-222 and
other radionuclides. The ANPRM discussed EPA's understanding of the
occurrence, health effects, and risks from these radionuclides, as well
as the available analytical methods and treatment technologies, and
sought additional data and public comment on EPA's planned regulation.
EPA's Science Advisory Board (SAB) reviewed the ANPRM and the four
draft criteria documents that supported it prior to publication of the
ANPRM in the Federal Register. EPA subsequently revised the criteria
documents and resubmitted them to the SAB for review during the summer
of 1990. EPA then revised the criteria documents based on this
additional round of SAB review and presented a summary of the SAB
comments and the Agency's responses in a 1991 Notice of Proposed
Rulemaking (NPRM).
B. The 1991 NPRM
On July 18, 1991 (56 FR 33050), EPA proposed a NPDWR for radon and
the other radionuclides addressed in the 1986 ANPRM. The 1991 notice,
which built on and updated the information assembled for the 1986
ANPRM, proposed an MCLG, an MCL, BAT, and monitoring, reporting, and
public notification requirements for radon in public water supplies.
The proposed MCLG was zero, the proposed MCL was 300 pCi/L, and the
proposed BAT was aeration. Under the proposed rule, all CWSs and
NTNCWSs relying on ground water would have been required to monitor
radon levels quarterly at each point of entry to the distribution
system. Compliance monitoring requirements were based on the arithmetic
average of four quarterly samples. The 1991 proposed rule required
systems with one or more points of entry out of compliance to treat
influent water to reduce radon levels below the MCL or to secure water
from another source below the MCL.
The proposed rule was accompanied by an assessment of regulatory
costs and economic impacts, as well as an assessment of the risk
reduction associated with implementation of the MCL. EPA estimated the
following potential impacts from the 1991 proposed MCL:
An estimated lifetime cancer risk of about two cancers for
every 10,000 persons exposed to radon in drinking water.
Avoidance of about 80 cancer cases per year.
About 27,000 public water systems affected.
A total annual cost of about $180 million.
The Agency received substantial comments on the proposal and its
supporting analyses from States, water utilities, and other stakeholder
groups. EPA has included in Appendix I of this preamble a summary of
major public comments on the 1991 NPRM and how EPA subsequently
addressed those comments.
C. 1994 Report to Congress: Multimedia Risk and Cost Assessment of
Radon
In 1992, Congress directed EPA to report on the multimedia risks
from exposure to radon, the costs to control this exposure, and the
risks from treating to remove radon. EPA's 1994 Report to Congress
(USEPA 1994a) estimates the risk, fatal cancer cases, cancer cases
avoided and costs for mitigating radon in water and in indoor air. The
Report found that cancer risks from radon in both air and water are
high. While radon risk in air typically far exceeds that in water, the
cancer risk from radon in water is higher than the cancer risk
estimated to result from any other currently regulated drinking water
contaminant.
EPA conducted a quantitative uncertainty analysis of the risks
associated with exposure to radon in
[[Page 59255]]
drinking water. This analysis, reviewed by EPA's SAB at the direction
of Congress, found that:
People are exposed to waterborne radon in three ways: (1)
From ingesting radon dissolved in water; (2) from inhaling radon gas
released from water during household use; and (3) from inhaling radon
progeny derived from radon released from water.
The estimated total U.S. cancer fatalities per year from
unregulated waterborne radon via all three routes of exposure were 192,
with a range from about 51 to 620.
The estimated annual cost was $272 million.
The 1994 Report to Congress noted that the regulated industry
estimated considerably higher costs than EPA for a 300 pCi/L MCL. For
example, in October 1991 the American Water Works Association (AWWA)
estimated national costs at $2.5 billion/year (for discussion of this
issue, see Section G of the Appendix to this preamble). The final part
of the report included the SAB's comments on each analysis presented
and an EPA discussion of the issues raised by the SAB.
D. 1997 Withdrawal of the 1991 NPRM for Radon-222
As required by the SDWA as amended, EPA withdrew the MCLG, MCL, and
monitoring, reporting, and public notification requirements proposed in
1991 for radon-222 on August 6, 1997 (62 FR 42221). No other provision
of the 1991 proposal was affected by this withdrawal.
E. 1998 SBREFA Small Business Advocacy Review Panel for Radon
In 1998, EPA convened a Small Business Advocacy Review Panel to
address the radon rule, in accordance with the Regulatory Flexibility
Act (RFA) as amended by the Small Business Regulatory Enforcement
Fairness Act (SBREFA). The Panel of representatives from EPA, the
Office of Management and Budget's Office of Information and Regulatory
Affairs, and the Small Business Administration's Office of Advocacy
reviewed technical background information related to this rulemaking,
and reviewed comments provided by small business and government
entities affected by this rule. The Panel made recommendations in a
final report to the Administrator which included a discussion of how
the Agency could accomplish its environmental goals while minimizing
impacts to small entities. For additional details, see Section XIV.B of
this proposal.
F. 1999 HRRCA for Radon in Drinking Water
EPA published the Health Risk Reduction and Cost Analysis required
by the SDWA on February 26, 1999 (64 FR 9559), and took public comment
for 45 days. EPA held a one-day public meeting in Washington, D.C. on
March 16, 1999, to present the HRRCA and the latest MMM framework, and
discuss stakeholder questions and issues. For details of the contents
of the HRRCA and EPA's response to significant public comment, see
Section XIII of this preamble.
Requirements
IV. To Which Water Systems Does This Regulation Apply?
The SDWA directs EPA to develop national primary drinking water
regulations (NPDWRs) that apply to public water systems (PWSs). The
statute defines a PWS as a system that provides water to the public for
human consumption if such system has at least 15 service connections or
regularly serves at least 25 individuals (Section 1401(4)(A)). EPA's
regulations at 40 CFR 141.2 define different types of PWSs. A community
water system (CWS) serves at least 15 service connections used by year
round residents or regularly serves at least 25 year-round residents. A
non-community system does not serve year-round residents; rather, it
(1) regularly serves at least 25 of the same persons over 6 months of
the year (a ``non-transient'' system such as a restaurant or church) or
(2) does not serve at least 25 of the same persons over 6 months of the
year (a ``transient'' system such as a campground or service station).
The regulation for radon in drinking water and the multimedia
approach for reduction of radon in indoor air (MMM program) proposed in
this notice applies only to CWSs that use ground water or mixed ground
and surface water (see following discussion regarding ``mixed''
supplies). The proposed regulation does not apply to transient water
systems because most people who use such facilities do so only
occasionally (e.g., travelers). There is no evidence that such short-
term exposure to radon would cause acute illness. The data on which
health risks from radon were determined for this rulemaking reflect
long-term exposure (see chapter 3 of the RIA (USEPA 1999f) HRRCA
section that discusses calculation of risk). And, as discussed next in
the context of non-transient non-community systems, even workers at
transient facilities who regularly drink the water would be expected to
have much less exposure than persons served by community water systems.
For these reasons, the proposed rule does not cover transient systems.
The proposed regulation also does not apply to non-transient non-
community (NTNC) water systems. EPA has determined that the risks posed
to persons served by NTNC systems (such as factories, hospitals, and
schools with their own drinking water wells) are substantially less
than the risks to persons served by community water systems.
The Agency recently completed a preliminary analysis of radon
occurrence (using data provided by six States), exposure and risk at
NTNC public water systems. Results from this preliminary analysis
indicate that even though radon concentrations are likely to be about
60 percent higher at NTNC locations than at locations served by a
community water system, the lifetime average risk to individuals who
work or attend school in buildings served by a groundwater-based NTNC
system is probably about 17 percent of the average risk to a worker
(and 6.7 percent of the average risk to a student) exposed in a home
served by a community ground water system. The reason that risks are
lower in the NTNC setting than the residential setting is that people
who are exposed at NTNC locations spend a smaller fraction of their
lifetime there than in the home. Further, in the particular case of
students most do not spend their entire school years in the same
school. EPA also notes that there is limited data in this area, and
more information is needed on how water is used in NTNC facilities and
on the contribution NTNC water use makes to radon inhalation risk. In
addition, the overall population served by NTNC PWSs is relatively
small (5.2 million vs. 89.7 million in homes served by CWSs using
ground water (USEPA 1999b)).
EPA acknowledges that the SDWA applies to all public water systems.
However, EPA believes that limiting the applicability of the radon rule
to community water systems where the risk from radon exposure is the
greatest meets a major goal of Congress in enacting the 1996 amendments
to the Act-to focus regulations on the most significant problems. In
the Conference Report adopting the 1996 amendments, Congress finds that
``more effective protection of public health requires--a Federal
commitment to set priorities that will allow scarce Federal, State, and
local resources to be targeted toward the drinking water problems of
greatest public health concerns. `` H. Rep. 104-182, Sec. 3. Moreover,
Congress specifically directed EPA in setting the NPDWRs for radon to
take into
[[Page 59256]]
consideration the costs and benefits of control programs for radon from
other sources. EPA has used this authority in this proposal to set the
MCL at 300 pCi/L and to encourage small systems to implement the MMM
program and comply with the AMCL. In both circumstances, EPA took into
account the fact that programs to control radon in indoor air promise
greater benefits at considerably less cost. EPA believes this cost-
effectiveness factor is also relevant in determining the applicability
of the radon rule. EPA's preliminary analysis of the risk associated
with exposure to radon from NTNC systems is that it is much less than
the risk from exposure from CWSs. For this reason, EPA has determined
that it is not cost-effective to regulate these systems.
However, it is important to note that this analysis is based on
limited occurrence and exposure data. In particular, relatively little
is known about the transfer factor for release of radon from water into
indoor air at NTNC locations, or about the equilibrium factor affecting
the amount of radon in indoor air at such locations. The calculations
done by EPA to date have assumed that certain values for these
parameters at NTNC locations are similar to those in homes, although
the data are limited.
The EPA is soliciting comment on the proposal to exclude NTNC PWSs
from the radon regulation. EPA is soliciting comments on the Agency's
preliminary analysis of radon exposure in NTNC PWSs, as well as any
additional data on key parameters, including data on the release of
radon from drinking water in the types of buildings (e.g., restaurants,
factories, churches, etc.) supplied by NTNC PWSs, and occurrence of
radon in NTNC PWSs. If information by commenters shows a greater
opportunity for risk reduction than identified in its initial analysis,
EPA may make the final radon rule applicable to NTNC PWSs without
further public comment.
With regard to systems using mixed ground and surface water,
current regulations require that all systems that use any amount of
surface water as a source be categorized as surface water systems. This
classification applies even if the majority of water in a system is
from a ground water source. Data currently in SDWIS does not identify
how many of these mixed systems exist although this information would
help the Agency to better understand regulatory impacts. To the extent
that systems correctly classified by SDWIS as surface water systems
also use ground water that may exceed the MCL/AMCL for radon, the costs
and benefits of the current proposal will be underestimated.
EPA is investigating ways to identify how many mixed systems exist
and how many mix their ground and surface water at the same entry point
or at separate entry points within the same distribution systems. For
example, a system may have several plants/entry points that feed the
same distribution system. One of these entry points may mix and treat
surface water with ground water prior to its entry into the
distribution system. Another entry point might use ground water
exclusively for its source while a different entry point would
exclusively use surface water. However, all three entry points would
supply the same system classified in SDWIS as surface water.
One method EPA could use to address this issue would be to analyze
Community Water System Survey (CWSS) data then extrapolate this
information to SDWIS to obtain a national estimate of mixed systems.
CWSS data, from approximately 1,900 systems, breaks down sources of
supply at the level of the entry point to the distribution system and
further subdivides flow by source type. The Agency could use the
national estimate of mixed systems to regroup surface water systems for
certain impact analyses when regulations only impact one type of
source. The Agency requests comment on this methodology and its
applicability for use in regulatory impact analyses.
V. What Is the Proposed Maximum Contaminant Level Goal for Radon?
A. Approach To Setting the Maximum Contaminant Level Goal (MCLG)
Under Section 1412(b)(4) of the SDWA, the EPA must establish
maximum contaminant level goals (MCLG) at the level at which no known
or anticipated adverse effects on the health of persons occur, and
which allow an adequate safety margin. Section 1412(b)(13) requires the
Administrator to set an MCLG for radon in drinking water.
B. MCLG for Radon in Drinking Water
As described in Section XII of this preamble, radon is a documented
human carcinogen, classified by EPA as a Group A carcinogen (i.e.,
there is sufficient evidence of a causal relationship between exposure
to radon and lung cancer in humans). Radon is classified as a known
human carcinogen based on data from epidemiological studies of
underground miners. This finding is supported by a consensus of opinion
among national and international health organizations. The
carcinogenicity of radon has been well established by the scientific
community, including the Biological Effects of Ionizing Radiation (BEIR
VI) Committee of the National Academy of Sciences (NAS 1999a), the
National Institute of Environmental Health Sciences, U.S. Department of
Health and Human Services, the World Health Organization's
International Agency for Research on Cancer (IARC 1988), the
International Commission on Radiological Protection (ICRP 1987), and
the National Council on Radiation Protection and Measurement (NCRP
1984). In addition, the Centers for Disease Control, the American Lung
Association, the American Medical Association, the American Public
Health Association and others have recognized radon as a significant
public health problem.
Based on the well-established human carcinogenicity of radon, and
of ionizing radiation in general, the Agency is proposing an MCLG of
zero for radon in drinking water. This decision is also supported by
the NAS' current recommendation for a linear non-threshold relationship
between exposure to radon and cancer in humans. In the BEIR VI report
(NAS 1999a), the NAS concluded that there is good evidence that a
single alpha particle (high-linear energy transfer radiation) can cause
major genomic changes in a cell, including mutation and transformation
that potentially could lead to cancer. They noted that even if
substantial repair of the genomic damage were to occur, ``the passage
of a single alpha particle has the potential to cause irreparable
damage in cells that are not killed.'' Given the convincing evidence
that most cancers originate from damage to a single cell, the committee
went on to conclude that ``On the basis of these [molecular and
cellular] mechanistic considerations, and in the absence of credible
evidence to the contrary, the committee adopted a linear non-threshold
model for the relationship between radon exposure and lung-cancer risk.
However, the BEIR VI committee recognized that it could not exclude the
possibility of a threshold relationship between exposure and lung
cancer risk at very low levels of radon exposure.'' The NAS committee
on radon in drinking water (NAS 1999b) reiterated the finding of the
BEIR VI committee's comprehensive review of the issue, that a
``mechanistic interpretation is consistent with linear non-threshold
relationship between radon exposure and cancer risk''. The committee
noted that the ``quantitative
[[Page 59257]]
estimation of cancer risk requires assumptions about the probability of
an exposed cell becoming transformed and the latent period before
malignant transformation is complete. When these values are known for
singly hit cells, the results might lead to reconsideration of the
linear no-threshold assumption used at present.'' EPA recognizes that
research in this area is on-going but is basing its regulatory
decisions on the best currently available science and recommendations
of the NAS that support use of a linear non-threshold relationship. For
additional information on this issue see Section XII.C.3. ``Biologic
Basis of Risk Estimation'' of this preamble.
VI. What Must a State or Community Water System Have in Its
Multimedia Mitigation Program Plan?
Today's proposed rule provides States (as defined in Section 1401
of the SDWA) with alternatives for controlling radon exposure. States
can develop a MMM program for the reduction of the higher risk of radon
in indoor air together with an alternative MCL (AMCL) of 4000 pCi/L to
address the highest levels of exposure from radon in drinking water. If
a State does not choose this option, the community water systems (CWS)
in that State must develop and implement local MMM program plans or
comply with an MCL of 300 pCi/L. See Section VII for information on the
regulatory expectations for CWSs.
A. What Are the Criteria?
1. Overview
EPA has identified four criteria that State MMM program plans are
required to meet to be approved by EPA. MMM program plans developed by
Indian tribes will be reviewed by EPA, according to these same
criteria. CWSs developing local MMM programs are also subject to these
criteria. These four criteria are: public participation, setting
quantitative goals, strategies for achieving goals, and a plan to track
and report results.
The criteria are based on a number of factors. Foremost, the
criteria reflect the elements found in successful voluntary action
programs for radon in indoor air that have been underway for more than
a decade. It is estimated that at the end of the year 2000, voluntary
programs to test homes and mitigate elevated radon levels in indoor air
and to encourage the construction of ``radon-resistant'' new homes will
have saved some 2500 lives; and, there is much more that can be done.
In the 1999 BEIR VI report (NAS 1999a), NAS concluded that 5,000 to
7,000 cancer cases (using two different methods) could be avoided
annually if all homes were below EPA's voluntary radon action level of
4 pCi/L of air. Incorporating these program elements into the criteria
required for the MMM programs builds on successful efforts and can be
expected to result in an even greater number of lives saved as more
States adopt programs and existing programs are strengthened and
expanded.
EPA has developed criteria that allow considerable flexibility for
those developing and expanding programs. EPA was urged by States and
other stakeholders to avoid prescribing the specific elements of the
MMM program in a ``one size fits all'' approach. States and CWSs
adopting MMM programs will be required to set quantitative goals for
mitigating elevated levels of radon in indoor air of existing homes and
building radon-resistant new homes, and to initiate strategies to
promote and increase these activities. However, there are requirements
that will be new to many of the State indoor radon programs. Those
adopting MMM programs will be required to involve the public in a
number of important (and on-going) ways, and to track and report
results from the implementation of the programs. With these additional
elements, both the affected public and EPA will be able to assess the
success of the MMM programs. Stakeholder input and EPA's experience
with the national voluntary program and the State indoor radon programs
led EPA to conclude that these criteria will provide the basis for a
program that meets the statutory directive for equal or greater risk
reduction benefits.
The Agency also considered equity-related issues concerning the
potential impacts of MMM program implementation. There is no factual
basis to indicate that minority and low income or other communities are
more or less exposed to radon in drinking water than the general
public. However, some stakeholders expressed more general concerns
about equity in radon risk reduction that could arise from the MMM/AMCL
framework outlined in SDWA. One concern is the potential for an uneven
distribution of risk reduction benefits across water systems and
society. Under the proposed framework for the rule, customers of CWSs
complying with the AMCL could be exposed to a higher level of radon in
drinking water than if the MCL were implemented, though this level
would not be higher than the background concentration of radon in
ambient air. However, these CWS customers could also save the cost,
through lower water rates, of installing treatment technology to comply
with the MCL. Under the proposed regulation, CWSs and their customers
have the option of complying with either the AMCL (associated with a
State or local MMM program) or the MCL. EPA believes it is important
that these issues and choices be considered in an open public process
as part of the development of MMM program plans. Therefore, EPA has
incorporated requirements into the proposed rule that provide a
framework for consideration of equity concerns with the MMM/AMCL.
First, the proposed rule includes requirements for public participation
in the development of MMM program plans, as well as for notice and
opportunity for public comment. EPA believes that the requirement for
public participation will result in State and CWS program plans that
reflect and meet their different constituents' needs and concerns and
that equity issues can be most effectively dealt with at the State and
local levels with the participation of the public. In developing their
MMM program plans, States and CWSs are required to document and
consider all significant issues and concerns raised by the public. EPA
expects and strongly recommends that States and CWSs pay particular
attention to addressing any equity concerns that may be raised during
the public participation process. In addition, EPA believes that
providing CWS customers with information about the health risks of
radon and on the AMCL and MMM program option will help to promote
understanding of the health risks of radon in indoor air, as well as in
drinking water, and help the public to make informed choices. To this
end, EPA is requiring CWSs to alert consumers to the MMM approach in
their State in consumer confidence reports issued between publication
of the final radon rule and the compliance dates for implementation of
MMM programs. This will include information about radon in indoor air
and drinking water and where consumers can get additional information.
EPA is encouraging the States to elect to develop and implement
State-wide MMM program plans. Since almost all States currently have
State indoor radon programs, EPA considers the States to be best
positioned to develop strong MMM program plans that, when implemented,
will be expected to achieve equal or greater radon risk reduction when
compared to compliance with the MCL. For example, a State-wide plan can
take into account the within-State variations in indoor radon
potential, the differences in radon
[[Page 59258]]
levels in drinking water, the experienced coalitions and cooperative
partners that have been working to promote public action on indoor
radon, the technical expertise of State drinking water and indoor radon
programs, and many other factors. EPA expects that the States will be
best positioned to develop MMM program plans that are robust and
credible in terms of the level of public participation in the
development and review process, the goals that are to be achieved from
implementation of MMM, and the program strategies to be used.
In the development of State MMM program plans meeting EPA's
criteria and in the implementation of the State's MMM program plan, EPA
expects and strongly recommends that the State's programs responsible
for drinking water and for indoor radon coordinate and collaborate on
their efforts. This is particularly important because of the uniqueness
of the MMM/AMCL approach which addresses radon risk reduction in
drinking water and in indoor air in a multimedia manner that is outside
the normal regulatory structure for drinking water. Both programs have
important responsibilities and roles in making the AMCL and MMM program
approach successful in achieving optimal radon risk reduction. To this
end, EPA has included as a special primacy requirement (see Section
142.16 of the proposed rule) that States include in their primacy
revision application for the AMCL a description of the extent and
nature of coordination between the State's interagency programs (i.e.,
indoor radon and drinking water programs) on development and
implementation of the MMM program plan, including the level of
resources that will be made available for implementation and
coordination between these agencies.
CWSs developing local MMM program plans are also subject to these
criteria. CWS MMM program plans developed in the absence of a State
program are deemed to be approved by EPA if they meet the same criteria
and are approved by the State. States without a MMM program, as a
special condition of primacy (see Section 142.16 of the proposed rule),
will be required to review and approve local CWS MMM program plans and
to submit their process for approving such plans to EPA. The Agency
considered an approach under which it would directly review and approve
CWS MMM program plans. However, for several reasons, EPA is proposing
that States review local MMM program plans. EPA believes that
responsibility for such reviews is an appropriate and natural extension
of the States' primacy responsibilities for oversight and enforcement
of drinking water regulations. State review and approval of local MMM
program plans will ensure that all elements of the radon rulemaking--
both the MMM program as well as implementation of the AMCL/MCL--are
enforced through the State, rather than separating elements of the rule
between the Federal and State governments. Dividing responsibility in
such a way may complicate implementation of both elements of the radon
rule and be confusing to both CWSs and the public. EPA also believes
that the States are best positioned to assist CWSs, especially small
systems, in the development of local MMM programs plans to review and
approve local plans that meet the four criteria. States have a direct
and ongoing regulatory relationship with CWSs as a part of their
primacy authorities, as well as a major responsibility for public
health related policy and programs in the State. In addition, States
are aware of and sensitive to local public health needs and concerns,
as well as other issues, that may need to be considered in the
development and implementation of local MMM programs. For all these
reasons, EPA is proposing an approach today that would require the
States to review and approve local MMM program plans in accordance with
the same criteria used in EPA's review of State MMM program plans.
However, EPA solicits comments on other approaches, such as EPA review
and approval of local MMM program plans or other options intermediate
between sole State or sole Federal responsibility.
EPA anticipates, and recommends, that States would assist CWSs in
developing their local MMM program plans and would approve program
plans that meet the criteria and that reflect local radon
implementation issues as discussed in Section VI.F. In non-MMM States,
EPA is also including as a special primacy requirement that States
include in their primacy revision application for the MCL a description
of the extent and nature of coordination between interagency programs
(i.e., indoor radon and drinking water programs) on development and
implementation of the State's review and approval process for CWS MMM
program plans, including the level of resources will be made available
for implementation and coordination between these agencies.
2. Criteria for MMM Program Plans
The following four criteria are required for approval of State MMM
program plans by EPA. Local MMM program plans developed by community
water systems are deemed to be approved by EPA if they meet these
criteria (as appropriate for the local level) and are approved by the
State. The term ``State'', as referenced next, includes States, Indian
tribes and community water systems. EPA is requesting comment on each
of the criteria for approval of State, and CWS, MMM program plans. In
particular, EPA is requesting comment on whether the criteria need to
be more or less stringent, and the supporting rationale for EPA's
consideration of other potentially credible approaches.
(a) Description of Process for Involving the Public. (1) States are
required to involve community water system customers, and other sectors
of the public with an interest in radon, both in drinking water and in
indoor air, in developing their MMM program plan. The MMM program plan
must include:
A description of processes the State used to provide for public
participation in the development of its MMM program plan, including the
components identified in the following paragraphs b, c, and d;
A description of the nature and extent of public participation that
occurred, including a list of groups and organizations that
participated;
A summary describing the recommendations, issues, and concerns arising
from the public participation process and how these were considered in
developing the State's MMM program plan; and,
A description of how the State made information available to the public
to support informed public participation, including information on the
State's existing indoor radon program activities and radon risk
reductions achieved, and on options considered for the MMM program plan
along with any analyses supporting the development of such options.
(2) Once the draft program plan has been developed, the State must
provide notice and opportunity for public comment on the draft plan
prior to submitting it to EPA.
(b) Quantitative Goals. (1) States are required to establish and
include in their plans quantitative goals, to measure the effectiveness
of their MMM program, for the following:
(i) Existing houses with elevated indoor radon levels that will be
mitigated by the public; and,
(ii) New houses that will be built radon-resistant by home
builders.
EPA is proposing to require establishing quantitative goals in
these
[[Page 59259]]
two areas because they represent the most direct link to the risk
reduction benefits that are the ultimate objective of the MMM programs.
In addition, EPA analyses indicate that it is very cost-effective to
test and mitigate existing homes with elevated indoor radon levels. It
is also very cost-effective to build new homes radon-resistant,
especially in higher radon potential areas. In the existing indoor
radon program, EPA has been encouraging the States to promote testing
and mitigation in all areas of a State. EPA has also encouraged the
States to focus on their activities to promote radon-resistant new
construction on the highest radon potential areas (Zone 1) where
building homes radon-resistant is most cost-effective. However, it is
also cost-effective to build homes in medium potential areas (Zone 2),
as well as in ``hot'' spots found in most lower radon potential areas
(Zone 3).
EPA recognizes the States' (and CWSs') need for flexibility in
designing MMM programs reflecting their needs and circumstances, in
particular the extent to which opportunities are available for risk
reduction in mitigation of existing homes with elevated indoor radon
levels or in construction of new homes built radon-resistant. Some
States, in particular those with a preponderance of lower radon
potential areas (and for CWSs in lower radon potential areas), may find
it preferable to focus more heavily on testing and mitigation of
existing housing than on radon-resistant new construction.
EPA is requesting comment on whether there are alternative goals
that achieve radon risk reduction and the rationale for those goals.
EPA is also soliciting comments on the goals outlined in paragraph (b),
in particular on the appropriateness of the goals and whether the goals
need to be more or less stringent.
(2) These goals must be defined quantitatively either as absolute
numbers or as rates. If goals are defined as rates, a detailed
explanation of the basis for determining the rates must be included.
EPA is proposing to provide this option, in part, because
opportunities available for risk reduction in mitigation of existing
homes with elevated indoor radon levels or in construction of new homes
built radon-resistant may vary between States and within States. In
addition, the level of new home construction may vary from year to year
in different parts of a State or in a local jurisdiction. In this
situation, it may be more appropriate to set goals for radon-resistant
new construction as a rate, rather than absolute numbers, to account
for this variability. This may be especially true for CWS developing
local MMM program plans where no new home construction is currently
taking place but may in the future.
(3) States are required to establish goals for promoting public
awareness of radon health risks, for testing of existing homes by the
public, for testing and mitigation of existing schools, and for
construction of new public schools to be radon-resistant, or to include
an explanation of why goals were not established in these program
areas.
EPA is proposing that States have this option of defining goals as
absolute numbers or as rates because, while awareness of radon health
risks is a necessary element and a first step in getting the public to
take action on indoor radon, public awareness, in and of itself, does
not constitute radon exposure reduction. It does, however, help to
facilitate informed choice by the public regarding radon testing and
mitigation. Since the level of awareness on the health effects of radon
is already high in many States, EPA is proposing to give flexibility to
the States on this goal. In the case of radon in schools, many States
have undertaken a range of activities to address radon in schools and
some have done extensive testing, in some cases passing State
legislation requiring the State to test public schools. Therefore, EPA
is proposing to give States the option of setting these goals for
schools. Although this approach provides flexibility in goal setting,
EPA strongly encourages those States which do not have high levels of
public awareness on radon and where there has been limited testing of
public schools across the State to set goals in these areas. EPA is
soliciting comment on whether States should be required to set
quantitative goals in all or some of these areas in paragraph (b)(3).
(c) Implementation Plans. (1) States are required to include in
their MMM program plan implementation plans outlining the strategic
approaches and specific activities the State will undertake to achieve
the quantitative goals identified in paragraphs (b)(1) and (b)(2). This
must include implementation plans in the following two key areas:
(i) Promoting increased testing and mitigation of existing housing
by the public through public outreach and education and during
residential real estate transactions.
(ii) Promoting increased use of radon-resistant techniques in the
construction of new homes.
(2) If a State has included goals for promoting public awareness of
radon health risks; promoting testing of existing homes by the public;
promoting testing and mitigation of existing schools; and promoting
construction of new public schools to be radon resistant, then the
State is required to submit a description of the strategic approach
that will be used to achieve the goals.
(3) States are required to provide the overall rationale and
support for why their proposed quantitative goals identified in
paragraphs (b)(1) and (b)(2), in conjunction with their program
implementation plans, will satisfy the statutory requirement that an
MMM program be expected to achieve equal or greater risk reduction
benefits to what would have been expected if all public water systems
in the State complied with the MCL.
(d) Plans for Measuring and Reporting Results. (1) States are
required to include in the MMM plan submitted to EPA a description of
the approach that will be used to assess the results from
implementation of the State MMM program, and to assess progress towards
the quantitative goals in paragraphs (b)(1) and (b)(2). This
specifically includes a description of the methodologies the State will
use to determine or track the number of existing homes with elevated
levels of radon in indoor air that are mitigated and the number or the
rate of new homes built radon-resistant. This must also include a
description of the approaches, methods, or processes the State will use
to make the results of these assessment available to the public.
(2) If a State includes goals in paragraph (b)(3) for promoting
public awareness of radon health risks; testing of existing homes by
the public; testing and mitigation of existing schools; and,
construction of new public schools to be radon-resistant; the State is
required to submit a description of how the State will determine or
track progress in achieving each of these goals. This must also include
a description of the approaches, methods, or processes the State will
use to make these results available to the public.
B. Why Will MMM Programs Get Risk Reduction Equal or Greater Than
Compliance With the MCL?
The National Indoor Radon Program implemented by EPA, States and
others, has achieved substantial risk reduction through voluntary
public action since the release of the original ``A Citizen's Guide to
Radon'' in 1986 (USEPA 1986) (updated: USEPA 1992b) and the U.S.
Surgeon General's recommendation in 1988 (US EPA, 1988b) that all homes
be tested and elevated radon levels be reduced. The program has been
[[Page 59260]]
successful in achieving voluntary risk reduction on indoor radon
through a variety of program strategies. It is important to keep in
perspective the comparatively large potential for risk reduction that
can be achieved if all existing homes with indoor radon levels at or
above EPA's voluntary action level for indoor radon of 4 pCi/L in the
U.S. were mitigated (approximately 6 million homes). In addition there
is the potential for significant risk reduction potential if the
approximately 1 million new homes built annually in the U.S. were built
radon-resistant. Based on the estimated number of existing homes fixed
and the number of new homes built radon-resistant since the national
program began in 1986, EPA estimates that a total of more than 2,500
lives will be saved through voluntary indoor radon risk reduction
efforts expected to take place up through the year 2000. Every year the
rate of lives saved increases as more existing houses with elevated
radon levels are fixed and as more new houses are built radon-
resistant. On average this rate of lives that will be saved from these
risk reduction actions increases by about 30 additional lives per year.
EPA estimates that for the year 2000, the rate of radon-related lung
cancer deaths that will be avoided from mitigation of existing homes
and from homes built radon-resistant in high radon areas will be about
350 lives saved per year (USEPA 1999i).
Under the radon provision of SDWA, if all States adopted the AMCL,
all State MMM programs together must be expected to result in at
minimum about 62 cancer deaths averted annually; equal to what would be
achieved with universal compliance with the MCL. Unlike these health
risk reduction benefits which remain constant from one year to the
next, the rate of health benefits from reducing radon in indoor air, as
noted previously, steadily increases every year with every additional
existing home that is mitigated and with every new home built radon-
resistant. This steady incremental risk reduction offered by mitigation
of existing homes with elevated indoor radon and building homes radon-
resistant, especially during real estate transactions and through
builder and consumer education and State and local adoption of radon-
resistant building codes, holds the potential for substantial long-term
risk reduction. NAS in their 1999 BEIR VI Report, concluded that up to
one third (i.e., 5,000 to 7,000) of their estimated 15,000 to 22,000
annual radon-related lung cancer deaths in the U.S. could be avoided if
all homes were below EPA's voluntary radon action level of 4 pCi/L of
air (NAS 1999a). This does not include the risk reduction that is
achieved from new homes built radon-resistant. The one million new
homes on average being built every year represent a significant radon
risk reduction opportunity. Therefore, a critical element for MMM is to
utilize and build on the indoor radon program framework to achieve
``equal or greater'' risk reduction rather than focusing efforts on
precisely quantifying the much more limited risk reduction that will
not occur in community water systems complying with the AMCL (i.e., the
difference in the risk reduction between the MCL and the AMCL).
C. Implementation of an MMM Program in Non-Primacy States
A State that does not have primary enforcement responsibility for
the Public Water System Program under Section 1413 of the SDWA
(``primacy'') and where EPA administers the CWS program may still
develop a State-wide MMM program plan. EPA would not expect to develop
an MMM program plan where the State elects not to develop a State-wide
MMM program plan. Accordingly, CWSs in such jurisdictions would be
required to comply with the more stringent MCL or develop local MMM
program plans for approval by EPA.
The SDWA authorizes all States to develop and submit a MMM program
plan to mitigate radon levels in indoor air for approval by the
Administrator under Section 1412(b)(13)(G). EPA is proposing that
States that do not have primacy may submit a plan to EPA that meets the
criteria of 40 CFR 141.302. If the State's plan is approved, the State
would be subject to all reporting and compliance requirements of 40 CFR
141.303. Community water systems in States with approved MMM programs
would comply with the AMCL of 4000 pCi/L, and would be subject to the
requirements for monitoring and analytical methods in 40 CFR 141.20.
EPA would continue to administer compliance with the MCL/AMCL, and with
monitoring and methods requirements.
D. Implementation of the MMM Program in Indian Country
Under this proposal, States can develop State-wide MMM programs for
the reduction of radon in indoor air, and community water systems in
such States can then comply with an AMCL of 4000 pCi/L (rather than an
MCL of 300 pCi/L). Under Section 1451 of the SDWA, the Administrator of
EPA is authorized to treat Indian Tribes in the same manner as States.
The proposal provides tribes the option of seeking ``treatment in the
same manner as a State'' for the purposes of assuming enforcement
responsibility for a community water system program, and developing and
implementing an MMM program. If a tribe does not choose to implement an
MMM program, any tribal CWS may develop an MMM program plan for EPA
approval, under the same criteria described previously.
EPA is proposing to amend the ``treatment as a State'' regulations
to allow tribes to be treated in the same manner as States for purposes
of carrying out the MMM program. Under this proposal, a tribe would not
need to demonstrate that it qualified for treatment in the same manner
as a State for any other purpose other than the MMM provisions. Tribes
may want to seek treatment in the same manner as a State for this
limited purpose to the extent that radon is a significant problem on
tribal lands because the MMM program provides an opportunity to focus
resources on reducing the higher risk exposure--indoor air--and
addressing radon in drinking water at the highest levels of exposure.
EPA is proposing to amend the treatment in the same manner as State
regulations (40 CFR 142.72 and 40 CFR 142.78) to obtain treatment as a
State status solely for the purpose of implementing the MMM
authorities. Tribes can, of course, always apply to be treated in the
same manner as a State for primacy over the Public Water Supply Program
under 40 CFR 142.72.
A tribe applying for authority to develop and implement an MMM
program plan that has met the criteria under 40 CFR 142. 72 to be
treated in the same manner as a State for any purpose will not need to
reestablish that it meets the first two criteria (40 CFR 142.72 (a) and
(b)) and needs to provide only information in 40 CFR 142.76 that is
necessary to demonstrate that the criteria in 40 CFR 142.72 (c) and (d)
are met for the MMM program plan. A tribe whose application for
authority to carry out the MMM program is approved must develop and
implement a MMM program plan in accordance with 40 CFR 141.302 and
141.303.
E. CWS Role in State MMM Programs
EPA anticipates that CWSs, especially small systems, would have a
limited role in State-wide MMM programs. For example, States may
develop information brochures on radon that could be distributed
locally by CWSs. EPA expects that States will want to consult with
CWSs, small and large, in
[[Page 59261]]
making a determination about the nature and scope of the role, if any,
of CWSs in implementing a State-wide MMM program. During EPA's
stakeholder process, many States and CWSs agreed that States were best
positioned to design and implement effective State-wide MMM programs
and that it was not apparent what role CWSs might take in such a
program. However, CWSs do have important responsibilities for
communicating information on radon to their customers (see Section
VI.G).
F. Local CWS MMM Programs in Non-MMM States and State Role in Approval
of CWS MMM Program Plans
The regulatory expectation of small community public water systems
(CWSs) is that they meet the AMCL and be associated with a MMM program-
either developed by the State and approved by EPA or developed by the
CWS and approved by the State. EPA strongly recommends that States
choose to develop and implement State-wide MMM programs as the most
cost-effective approach to manage the health risks from radon. In those
cases where States do not elect to do a State-wide MMM program, CWSs
would need to notify the State of its intention to develop and submit a
local MMM program plan to the State (4 years after publication of the
final rule in the Federal Register). EPA believes that, in all cases,
the regulatory burden of complying with AMCL and implementing a MMM
program will be considerably less than complying with the more
stringent regulatory level for radon in drinking water. EPA believes
that the MMM/AMCL is the appropriate standard for CWSs, especially for
small systems, because it results in greater radon risk reduction and
makes better use of limited resources. EPA believes that the four
criteria for plan approval can be applied to CWS local MMM program
plans (as appropriate for the local level), commensurate with the
unique attributes of these CWSs and their service areas. As previously
discussed in more detail, these four criteria are: public
participation, setting quantitative goals, strategies for achieving
goals, and a plan to track and report results.
In general, EPA expects that CWSs would be able to meet the four
criteria by carrying out a wide range of diverse activities, many of
which are well within the expertise of CWSs. However, small CWSs would
not necessarily be expected to perform some of the activities entirely
on their own. In carrying out certain activities, small CWSs would be
expected to seek help from others in order to build upon and take
advantage of existing CWS and State networks. The existing State indoor
radon programs, for example, operate in large measure through a network
of State and local partners such as the American Lung Association, the
National Association of Counties, the National Environmental Health
Association, the National Safety Council, consumer advocacy groups,
non-government organizations, and other local and county governmental
organizations. CWSs should be able to use the same networks and their
capabilities, and State radon in indoor air programs should help
facilitate these contacts. The following provides some additional
perspective on the four criteria relative to CWS MMM programs.
Public Participation: Thorough public participation is certainly
within the capability of CWSs. Systems are often required in the course
of CWS activities, such as operation, maintenance, water bill
collection, violation notification, and planning for new facilities, to
involve, communicate with, inform, and in other ways interact with the
public. Thus, these systems already engage, to a significant degree, in
public outreach and communication. EPA expects that such expertise can
readily be directed toward the particular public participation
requirements associated with MMM programs. Public participating during
development of local MMM plans will help ensure greater local support
for and implementation of the CWS MMM programs.
Quantitative Goals: EPA notes that the quantitative goals that
CWSs, especially small CWSs, typically will need to establish may be
rather modest compared to those that would be expected for State-wide
programs. The level of risk reduction needed to ensure ``equal or
greater'' risk reduction be achieved (as if the MCL were being met)
from a local MMM program plan is a function of and takes into account
factors such as the size of the population served, level of radon in
drinking water, and most importantly, the needs and goals of the
community.
Strategies for Achieving Goals: EPA recognizes that promoting
public action in the areas of new homes built radon-resistant and
mitigation of existing homes with elevated levels of radon in indoor
air will be entirely new ventures for CWSs. However, EPA believes CWSs,
including small CWSs, will be capable of conducting various activities
designed to promote testing and mitigation of existing homes with
elevated levels of radon in indoor air and building of new homes to be
radon-resistant. Such activities include public education programs,
provision of radon test kits, establishing networks with local health
and government officials to gain their support and involvement in MMM
implementation, meeting with community leaders, customers, local real
estate and home building officials and organization, utilizing existing
information distribution network employed by CWSs, and other types of
activities to promote public action on indoor radon. EPA expects that
MMM program strategies for CWSs will be less comprehensive and far
reaching than those of State MMM programs, and will need to reflect the
local character of the community served by the CWS.
Tracking and Reporting of Results: EPA recognizes that assessing or
tracking progress towards meeting these goals also represents a new
responsibility for CWSs. However, CWSs may be able to build upon their
experience and networks for communicating with customers and
identifying their needs or concerns and find ways to collect
information about actions taking place in the community. To track homes
built or modified to be radon resistant, CWSs may be able to obtain
needed information from various local and State programs and offices
and other organizations in its network. CWS may also choose to employ
contractor support or consultant services to obtain this information or
to help track other MMM related activities. EPA also expects the States
to provide assistance to CWSs in developing their tracking and
assessment approach based on State experience in determining the
results of their State indoor radon programs. EPA recognizes that CWSs'
options for tracking results may be more limited than those available
to the States, and that States should consider such limitations in
their five-year review of local programs.
CWSs may find it useful to combine efforts with adjacent CWSs for
purpose of developing and implementing joint MMM programs, thereby
broadening their combined expertise, local infrastructure and
institutional bases, and network of partners. EPA also expects that
privately-owned, as well as publicly owned, CWSs can avail themselves
of these same kinds of networks, partnership, and consultant services.
Private systems will generally also be well connected to the municipal
entities in the jurisdictions in which they operate.
The report of the Small Business Advocacy Review Panel included a
discussion of the concept of a ``model MMM program'' for small systems
which would not be required but could
[[Page 59262]]
provide a workable option for small systems. It might address potential
concerns of the smallest systems that anticipate they may lack the
resources and expertise to develop an MMM program. As discussed
subsequently in Section VI. H., EPA has concerns in general about the
appropriateness and applicability of a ``one-size-fits-all'' approach
for MMM programs. A model approach, even for small CWSs, would not
address the unique, site-specific needs of different CWSs and their
associated communities. EPA is requesting public comment on the concept
of a model MMM program for CWSs.
As noted previously, EPA is strongly recommending that States
choose to develop and implement State-wide MMM programs as the most
cost-effective approach to manage the health risks from radon which
would preclude the need for water systems to develop such programs on
their own. EPA also believes the States which choose not to do an MMM
program have an important role, and are the best positioned, to assist
CWSs in development of local MMM program plans. EPA will also be
providing guidance to assist CWSs, including small CWSs, in the
development of local MMM programs. This section has discussed the
manner in which the four criteria could be applied to CWSs in non-MMM
States. EPA is requesting comment on approaches to applying these
criteria to CWSs, especially the smallest CWSs, in view of the
capabilities of these systems and their ability to get assistance from
others. EPA is also requesting comment on options that may be available
to CWSs, particularly, small systems, to develop and implement an MMM
program plan.
In summary, EPA recognizes that CWSs do not have the same
institutional base and infrastructure, legislative authority,
proportionate resource base, or indoor radon program experience as
States on which to base development of a local MMM program plan.
However, EPA believes that the four criteria for approval are equally
applicable to both States and CWSs, and can be applied to CWSs
(particularly small CWSs) in a manner that recognizes and accounts for
these differences. As discussed previously, the manner in which these
criteria are addressed by CWSs in local MMM program plans, and the
level and scope of effort, will necessarily differ from that embodied
in State plans. States should consider these differences in evaluating
CWS MMM program plans and in their five-year review of CWS MMM program
implementation. EPA believes that States, in particular, are best
positioned to assist CWSs, especially small systems, in the development
of local MMM programs that satisfy the four criteria, and expects them
to provide such assistance. In evaluating CWS plans, States should
exercise flexibility in their review and approval process, especially
for small CWSs, recognizing that they will not have the same
institutional and resource base or experience and may need to obtain
assistance from others.
The Agency expects that most systems in non-MMM States with radon
levels between 4,000 pCi/L and 300 pCi/L will develop and submit MMM
program plans. However, the Agency recognizes that some CWSs in non-MMM
States may elect not to develop a MMM program plan for a variety of
reasons. In these cases, certain options are available to small CWSs.
They may consider working with one or more other systems for the
purposes of developing and implementing an MMM program plan, in order
to take advantage of greater institutional capabilities. If a system
does not develop an MMM program plan on its own or together with other
systems, the system must comply with the MCL of 300 pCi/L through any
available means (e.g., blending, use of alternate sources, and
treatment).
From a risk communication standpoint, EPA wishes to convey to
customers of small CWSs that its regulatory expectation for these
systems is that they meet the AMCL and implement an MMM program.
However, CWSs can choose to meet the MCL rather than take the MMM
approach. If a CWS opts for the MMM/AMCL approach but is unable to
develop and successfully implement a State-approved MMM program plan,
it may be required as part of an enforcement order, to meet the MCL
rather than comply with the MMM/AMCL. The Agency requests comment on
this approach for small system MMM programs.
The SDWA provides that EPA will approve local water system MMM
program plans and EPA has developed the criteria to be used for
approving MMM program plans, as discussed in (A). EPA will review and
approve State MMM program plans. CWS MMM program plans that address the
criteria and are approved by the State are deemed approved by EPA. The
proposed rule requires States that do not have a State-wide MMM
program, as a condition of primacy for the radon regulation, to review
MMM program plans submitted by CWSs and to approve plans meeting the
four criteria for MMM program plans discussed in Section VI.A. of this,
including providing notice and opportunity for public comment on CWS
MMM program plans. EPA solicits comment on this approach to reviewing
and approving local MMM plans. Under SDWA, MMM program plans submitted
by CWSs are to be subject to the same criteria and conditions as State
MMM program plans. EPA believes that the States are best positioned to
assist CWSs, especially small systems, in the development and review of
local MMM program plans that meet the four criteria, and to have public
health oversight of the progress of the implementation of these local
radon risk reduction programs. EPA encourages those States not choosing
to develop a State-wide MMM program plan to exercise flexibility in
their review and approval of local MMM program plans, especially for
small CWSs, recognizing that CWSs will not have the same institutional
base, nor the State's program experience on indoor radon, on which to
base to local development of a MMM program plan. EPA expects that the
State drinking water programs and indoor radon programs will work
collaboratively in assisting CWSs that elect to develop and implement
local CWS MMM program plans and comply with the AMCL. In non-primacy
states, EPA will review and approve local CWS MMM program plans and
oversee compliance with the AMCL if the state chooses not to do a
state-wide MMM program plan. MMM program plans developed by Indian
Tribes or tribal community water systems will be reviewed by EPA. The
specific requirements of a CWS in a State with a State-wide MMM program
are addressed in Section VI.E. CWSs may choose to meet the MCL.
For those CWSs (both large and small) in non-MMM States that
develop local MMM program plans, the State would review the MMM program
at least once every 5 years and provide progress reports to the EPA in
keeping with the statutory requirements of the SDWA and this Section.
(States may also establish interim reporting requirements for the CWS
under a MMM program to help ensure adequate progress toward the goals
set forth in the local MMM program plan.) Failure of a CWS to develop
its MMM program plan by the required regulatory deadline or failure of
a CWS to implement its approved MMM program plan (5 years and 5\1/2\
years, respectively after the final rule is published) would be a
violation of this regulation unless the CWS is complying with the MCL.
It is expected that a CWS would be given time to correct any violations
relating to its MMM program
[[Page 59263]]
through an appropriate enforcement action.
G. CWS Role in Communicating to Customers
At a minimum, CWSs have important responsibilities for
communicating information on radon to their customers. Under the
requirements of the Consumer Confidence Rule (CCR), CWSs will be
required to provide key information on the health effects of radon
should the level of radon in drinking water exceed the MCL (or AMCL in
States with MMM programs). Today's action also updates the standard CCR
rule requirements and adds special requirements that reflect the
multimedia approach of this rule. The intent of these provisions is to
assist in clearer communication of the relative risks of radon in
indoor air from soil and from drinking water, and to encourage public
participation in the development of the State or CWS MMM program plans.
Today's action also proposes to require CWSs to add information to the
mandatory yearly report which would inform their customers on how to
get involved in developing their State or local CWS MMM program plan.
This information would include a brief educational statement on radon
risks, explaining that the principal radon risk comes from radon in
indoor air, rather than drinking water, and for that reason, radon risk
reduction efforts may be focused on indoor air rather than drinking
water. This information will also note that many States and systems are
in the process of creating programs to reduce exposure to radon, and
encourage readers to call for more information. This information would
be provided every year until the compliance date for implementation of
State MMM programs (or CWS local MMM programs in States without a
State-wide MMM program. (See Section X of this preamble for more
information on CCR and public notice requirements for radon). EPA is
also planning to develop public information materials on radon in
drinking water and indoor air as ``tools'' to assist CWSs, as well as
the States, Indian tribes, and others, with the risk communication
issues associated with the MCL, AMCL, and MMM.
H. How Did EPA Develop These Criteria?
EPA obtained extensive stakeholder input in developing the
regulatory criteria for State MMM program plans. Stakeholders
participating in this process represented many diverse groups and
organizations with an interest in radon, both from the perspective of
radon in drinking water and of radon in indoor air. This included State
drinking water and State radon program representatives, municipal and
privately owned public water system suppliers, local government
officials, environmental groups, and organizations representing State
health officials, county governments, public interest groups, and
others.
As part of the process of getting stakeholder input on development
of MMM guidelines and criteria, EPA presented several conceptual
framework options for MMM for discussion and consideration. Three
preliminary approaches were discussed: (1) To set specific numerical
targets in mitigations of existing houses and houses built radon-
resistant (as surrogates for lives saved) for each State to meet; (2)
to set a level of effort that States must demonstrate would be achieved
under their MMM plan; and (3) to set minimum core indoor radon program
elements required for all plans.
Under the first approach, specific targets to achieve ``equal''
risk reduction could be set using a variety of approaches and tools and
based on a number of factors, such as the level of radon in the
drinking water, the number of people served by that system, and other
factors. It would also require allocating among the States the total
number of lives saved nationally by universal compliance with the MCL
(estimated to be about 62 lives saved yearly). The allocation of lives
saved by States would likely lead to some State targets being fractions
of a life saved yearly, depending on the number of systems, radon
levels, and people served. Many stakeholders thought that significant
attention would need to be paid to the risk communication challenges of
communicating this approach to the public. Although some stakeholders
thought this approach might be workable, others did not consider it
universally applicable or workable and that it might preclude
flexibility and innovation.
The second approach, ``level of effort'', would focus more on a
plan for implementation of risk reduction strategies using a point
system where different risk reduction strategies (such as public
education, radon-resistant new construction code adoption, etc.) would
be assigned a specific number of points based on potential to achieve
health risk reduction. The number of State-specific points that a MMM
program plan would have to meet to be approved would require
determining the number of systems complying with the AMCL rather than
the MCL, the radon levels in their drinking water, and population
served. This approach would give States flexibility in choosing the
combination of indoor radon risk reduction strategies that best meets
the needs of that State by giving them a menu of approaches from
different categories of strategies with different assigned points.
There are two difficulties in implementing this approach that would
need to be addressed. First, it may be difficult to assign in advance a
specific quantified value for different strategies in terms of a
numerical outcome in risk reduction (i.e., in lives saved or in
existing homes mitigated or houses built radon-resistant). EPA
requested the National Academy of Sciences (NAS), as part of its
assessment of radon in drinking water, to ``prepare an assessment of
the health risk reduction benefits associated with various mitigation
measures [described in SDWA] to reduce radon levels in indoor air.''
Although the NAS included some review of the States' experience with
public education and risk communication, they did not include a
quantitative assessment of the ``health risk reduction benefits''
associated with specific ``mitigation measures'' referred to by SDWA.
Second, risk communication research has shown, and many stakeholders
agreed, that a variety of strategies must be employed simultaneously
when trying to get voluntary public actions on preventive health and
safety measures. It is often difficult to single out or characterize,
for example, the number of people who take voluntary health risk
reduction actions because of viewing a particular televised public
service announcement separate from other messages, activities,
communications, and efforts being implemented by society to reduce that
particular public health risk.
Setting specific State risk reduction targets or a level of effort
point system were considered in part to address language in the SDWA
radon provision that State plans approved by EPA are expected to
achieve health risk reduction benefits ``equal to or greater than the
health risk reduction benefits that would be achieved if each public
water system in the State complied with the maximum contaminant level
[MCL]* * *.'' As some stakeholders noted, there are complexities
associated with determining risk reduction targets (e.g., in pCi/L) for
indoor radon needed to substitute or ``make-up'' for some very small
level of risk reduction that would not occur if systems comply with the
AMCL. Careful attention would need to be paid to ensuring that this
[[Page 59264]]
approach did not produce the unintended effect of narrowly focusing or
limiting the risk reduction goals of MMM program plans. Some States and
other stakeholders were concerned that a complex approach, that may be
difficult to communicate to the public, could hamper voluntary public
action currently taking place on indoor radon. Some States thought that
they may have the data and/or tools that would permit such an approach.
The third conceptual approach was to require MMM program plans to
include a set of core program elements, without targets or points, to
be determined by EPA. This would require a set of basic program
elements that each State MMM program plan would have to incorporate to
be approved by EPA. In addition, the States could choose to add
additional program elements from a menu of strategies to be provided by
EPA. An example of implementation of a core program element might be
that each State would have to adopt radon-resistant new construction
standards into their State and local building codes, or require testing
and mitigation firms to register with the State and report numbers of
radon tests and mitigations conducted. Many stakeholders were concerned
that this approach might not provide sufficient flexibility needed by
the States to reflect their particular needs, including the scope of
the radon in drinking water and indoor radon problem, and the varying
extent to which the States have been addressing their indoor radon
problem through their existing State radon programs.
EPA is soliciting public comment on these three alternative
conceptual frameworks for MMM program plans that were examined through
the stakeholder process and is also requesting public comment on other
potential frameworks and rationale for why and how these would achieve
increased radon risk reduction.
While stakeholders had differing views of the three conceptual
approaches presented by EPA for discussion purposes, a number of mutual
concerns and issues integral to formulation of a conceptual framework
for MMM were identified. The following set of broad issues and concerns
raised by stakeholders were considered in the development of the
required criteria that EPA is proposing.
A uniform approach, that is, a ``one size fits all'' approach to
MMM might not provide States with the flexibility they need to custom
tailor their plans to their needs. Every State is different in terms of
the extent and magnitude of the indoor radon problem, the nature of the
existing State indoor radon program, the levels of radon in public
water supplies, and many other factors.
Because the SDWA framework for radon permits States to choose to
adopt either the MCL or AMCL/MMM option, some stakeholders believed
that States might be less inclined to adopt the MMM/AMCL approach if it
were considered too complex and difficult to implement and communicate
to the public. The approach needs to be simple and straightforward,
provide flexibility to accommodate the variety of needs in different
States, and encourage innovation at the State and local level.
MMM will be most effective if it is built on and consistent with
the foundation and infrastructure of the existing State indoor radon
programs. States are better positioned than public water suppliers to
achieve radon risk reduction under MMM programs. Most States currently
have a voluntary radon program. Some States noted the need for some
consistency between the criteria and objectives for MMM program plans
and the goals, priorities, and EPA's existing State Indoor Radon Grant
(SIRG) program guidance.
States and other stakeholders raised concerns about the potential
relationship between MMM and the current State indoor radon programs.
Stakeholders strongly encouraged EPA to carefully identify and consider
the potential for negative impacts of MMM requirements on current State
efforts on indoor radon. In particular there were concerns that
attention and resources might be diverted to the MMM program. States
might choose not to do a MMM program if the effectiveness or
infrastructure of their current indoor radon program might be reduced,
or if it does not help States meet the goals of their voluntary
programs. This would be counter-productive if it resulted in reduced
efforts and diminished infrastructure of a State's voluntary program
already achieving indoor radon risk reduction.
Some States felt it was important to have extensive public debate
and examination of any program proposed by the State in order to get
public support for the AMCL and MMM approach.
A number of stakeholders noted the need for MMM programs to have
definable endpoints or goals, show how these endpoints will be
attained, and describe how results will be determined. Some States
indicated the importance of demonstrating to the public that the
program is achieves radon risk reduction.
Stakeholders noted that the level of risk reduction that can be
achieved by focusing resources and effort on radon in indoor air is
significantly greater than what can be achieved by universal compliance
with the MCL. MCL-based risk reduction targets would also be
significantly smaller than the risk reduction already being achieved.
Therefore it is important to focus on the greater risk reduction
potential for radon in indoor air, and on enhancement of indoor radon
programs, rather than focus on the smaller risk reduction potential
from radon in water.
In developing and deciding on proposed criteria, EPA took into
account these stakeholder views and concerns, as well as EPA's goals
for MMM and the current approach used by EPA and the States to get
indoor radon risk reduction. This information and experience taken
together led to the proposed MMM criteria that are based upon three
elements: (1) Involve the public in development of MMM; (2) track the
level of indoor radon risk reduction that occurs; and, (3) build on the
existing framework of State indoor radon programs.
First, stakeholders suggested that extensive public participation
in the development of a State MMM program plan is important. One
important approach is to involve various segments of the public, from
community water system customers to key public health and other
organizations, the business community, local officials, and many
others. The public needs to be informed about and participate in the
MMM development process to ensure that the goals and other elements of
the plan will be publicly supported, responsive to the needs of the
various stakeholders, and meet public and State goals for reducing
indoor radon. Such a process may also result in increased public
awareness and voluntary action to reduce the levels of indoor radon.
Stakeholder involvement can help States clearly define goals and design
the process and strategies for meeting these goals. EPA recognizes that
there are a variety of non-quantitative and quantitative approaches,
tools, and types of information that can be used to develop goals, but
public input is very important to this process. The public involvement
in development and examination of plans will help to get support and
buy-in from all stakeholders to a set of goals, program strategies, and
results measurement, and thus, helps to ensure program success.
Second, a successful MMM program plan needs to include a provision
for determining progress on reducing the public's exposure to indoor
radon, and for reporting back to the public. In the case of indoor
radon, risk reduction results can be evaluated by tracking or
[[Page 59265]]
in some way determining the level of existing home mitigation and new
homes built radon-resistant. A few States already track this
information closely. Many do not. EPA believes that there are a variety
of approaches currently being used, such as statistically-based
surveys; State requirements for tracking testing and mitigation by
radon testing and mitigation companies; voluntary agreement by builders
to provide information on construction of radon-resistant homes; and
other approaches. EPA also recognizes the importance of providing
States the flexibility to craft new and innovative approaches for
tracking and assessing progress. Through implementation of a State-wide
MMM/AMCL approach, States may be able to provide new incentives and
opportunities for gathering the information the State will need to
demonstrate to the public, and EPA, that progress is being made in
getting public action to reduce radon risks.
Third, building MMM on the framework of existing State indoor radon
programs takes advantage of the existing programs already working to
get public action on indoor radon. Nearly every State currently has a
program with existing policies, public outreach and education programs,
partner networks and coalitions, and other infrastructure. States have
used the State Indoor Radon Grant (SIRG) funds available under Title
III of the Toxics Substances Control Act (TSCA) to develop a variety of
radon strategies, including distributing information materials to
educate the public, maintaining radon hotlines, conducting training
programs, providing technical assistance, operating certification
programs for the radon industry, setting up regulatory requirements for
industry reporting of testing and mitigation, conducting surveys
(testing) of homes and schools, working with local governments in high-
risk areas to establish incentive programs for radon-resistant new
construction, and many other activities. Many of these activities are
consistent with the findings of the National Academy of Sciences. They
found three factors were most important for motivating the public to
test and fix their home: (1) A radon awareness campaign; (2) promoting
the widespread voluntary testing by the public of indoor radon levels;
and (3) educating the public about mitigation and ensuring the
availability of qualified contractors. The reinforcement and
augmentation of these types of efforts through MMM programs is expected
to result in increased levels of testing and mitigation of existing
homes by the public and of homes being built to be radon-resistant.
The ``mitigation measures'' set forth in the 1996 SDWA are similar
to those being used in the existing national and State radon programs.
Section 1412 (b)(13)(G)(ii) provides that State MMM programs may rely
on a variety of ``mitigation measures'' including ``public education,
testing, training, technical assistance, remediation grants and loans
and incentive programs, or other regulatory or non-regulatory
measures''. These represent many of the same strategies that are
integral to the indoor radon program strategy, as well as those
outlined in the 1988 Indoor Radon Abatement Act.
The risk reduction achieved to date through the national and State
radon programs has been achieved primarily through a non-regulatory
approach. The SIRG guidance for implementing a program also outlines
and recommends indoor radon program priorities, encourages States to
develop narrative descriptions of how they intend to address the
priority areas, and encourages the establishment of goals for
awareness, testing and mitigation of homes and schools, and radon-
resistant new construction. Under SIRG, the States are required to
submit a list of their activities and workplans for each project that
will be done under the grant. While EPA's SIRG guidance requires a list
of program activities, it is not currently a Federal requirement under
the Indoor Radon Abatement Act of 1988 or under SIRG that State indoor
radon programs to: (a) publicly set goals for awareness, testing,
mitigation and new construction; (b) develop and implement a strategic
plan for action through real estate transactions, new home
construction, testing and fixing schools, and getting the public to
test and fix their homes; (c) develop and implement approaches to track
and measure the results of their strategic plans and activities and
report those results to the public; and (d) directly involve the public
in the development of the States' program goals and strategic plans.
EPA is proposing that, in order to have an approved MMM program plan,
States now be required to take these steps.
EPA believes this augmentation of State programs required under the
criteria will result in an increased level of risk reduction. States
will develop their plans with direct public participation in setting
goals, develop strategic plans in key areas, and develop approaches for
tracking and measuring results against goals. EPA also expects that
substantial and constructive public participation in the development
process of the State's MMM program plan is likely to result in a
program that meets the public's needs and concerns on an important
public health issue, as well as in greater public awareness of the
health effects of radon and in increased voluntary action by the public
to address their risks from indoor radon. Given EPA's estimate of the
expected increase in the yearly rate of lung cancer deaths avoided from
the current voluntary program, EPA expects that State MMM program plans
meeting these four criteria will achieve equal, or much more likely,
greater health risk reduction benefits.
I. Background on the Existing EPA and State Indoor Radon Programs
Implementation of EPA's current national strategy to reduce public
health risks from radon in indoor air has focused on using a
decentralized management and risk communication approach in partnership
with States, local governments and a network of national organizations;
a continuum of risk reduction strategies; and, a strong focus on key
priorities. Reduction of indoor radon levels has the potential to yield
very large risk reduction benefits through pursuit of a wide range of
approaches including the availability of relatively inexpensive
testing, mitigation, and new construction techniques to reduce the risk
from indoor radon. National, State, and local efforts continue to
proactively encourage the public to test and fix their homes, promote
action on radon in association with real estate transactions, and
promote the construction of new homes with radon-resistant techniques
through institutional changes such as local adoption of new
construction standards and codes.
Prior to 1985 the federal government and only a few States had
initiated activities to address indoor radon problems. The initial
foundation and scope of State programs was determined by the different
needs of the States. For example, some Western States developed
programs to assist citizens living on or near uranium mines or mill
tailings sites. When very high levels of radon in homes in the area
known as the Reading Prong in the Northeastern U.S. were discovered in
late 1984, the Agency began to develop and to implement a coordinated
national radon program. Some Eastern States situated over the Reading
Prong began to develop strong programs in response to homes being found
with radon levels in the hundreds and thousands of pCi/L of air.
However, there was no coordinated government program, or testing and
[[Page 59266]]
mitigation industry, to address the risks posed by radon and only a
very small fraction of the public was even aware of the problem.
Since then, there has been significant progress in the nation's
program to promote voluntary public action to reduce the health risks
from radon in indoor air. EPA's non-regulatory Radon Program has
established a partnership between federal, State, local and private
organizations, as well as private industry, working together on
numerous fronts to promote voluntary radon risk reduction. This
partnership initially focused programs on increasing public awareness
of the problem and providing the public with the necessary resources,
including a range of technical guidance and information, to enable them
to reduce their health risks through voluntary actions across the
nation. Congress endorsed this strategy and strengthened the indoor
radon program through the Superfund Amendments and Reauthorization Act
of 1986, and again in 1988 through passage of the Indoor Radon
Abatement Act. The Superfund Amendments and Reauthorization Act of 1986
(SARA) authorized EPA to conduct a national assessment of radon in
residences, schools, and workplaces. The 1988 Indoor Radon Abatement
Act (IRAA), an amendment to the Toxic Substances Control Act.
established the overall long-term goal of reducing indoor radon levels
to ambient outdoor levels, required the development and promotion of
model standards and techniques for radon-resistant construction, and
established the State Indoor Radon Grant program (SIRG). IRAA also
directed EPA to study radon levels in the U.S., evaluate mitigation
methods to reduce indoor radon, establish proficiency programs for
radon detection devices and services, develop training centers, provide
the public with information about radon, and assist States to develop
and implement programs to address indoor radon.
Recognizing the importance of working in partnership with the
States and leading national organizations, EPA developed a
decentralized system for informing the public about the health risks
from radon, consisting primarily of State and local governments and key
national organizations, with their state and local affiliates, who
serve as sources of radon information and support activities to the
public. EPA has worked with the States to help establish and enhance
effective State indoor radon programs and develop basic State
capabilities needed for assisting the public in reducing their risk
from indoor radon. EPA developed and transferred technical guidance on
radon measurement and mitigation to the States, the private sector, and
the public.
A key initiative in this effort to build State Radon Programs has
been the State Indoor Radon Grant (SIRG) Program, which provides
funding to help States develop and operate effective and self-
sustaining radon programs. As of August 1999, forty-five States are
currently participating in the SIRG program. These grants have been
instrumental in establishing State radon programs or in helping States
expand their radon programs more quickly than they otherwise could
have.
EPA, the States and national and local partners are using a mixture
of diverse strategies that range from the more flexible, such as
providing information to the public to encourage the public to act, to
more prescriptive, such as providing incentives that give some
advantage for taking action, or to adopting policies and requirements
that mandate certain actions. As a result, many initiatives are
underway today both to actively encourage and motivate homeowners to
test and fix their homes as well as to institutionalize risk reduction
through testing and mitigation during real estate transactions and
through construction of new homes to be radon-resistant.
EPA and the States, working with key national and local
organizations, have developed a wide range of channels for delivering
information to their members, affiliates and other target audiences.
Many organizations have their own ``hotlines,'' journals, brochures,
newsletters, press releases, radio and television programs, national
conferences, and offer training and continuing education programs.
These partners collaborate to urge public action on radon though a wide
variety of strategies including information, motivation, incentives,
and state and local mandates. The public receives a consistent message
on radon from EPA, the States, and a number of other key, respected,
and credible sources. Each target audience, like physicians or school
nurses or local government officials, becomes in turn a source of
information for new target audiences like their patients and local
constituents. This approach is comparable to that used to encourage
people to take various other voluntary preventive measures to reduce
their risk of various health and safety risks. Some of the national
organizations that EPA and the States work with include the American
Lung Association, the National Association of City and County Health
Officials, the National Parent Teacher Association, the Asian American
and Pacific County Health Officials, the Association of State and
Territorial Health Officials, the National Environmental Health
Association, the National Association of County Officials, the Consumer
Research Council of Consumer Federation of America, the National Safety
Council, and many others.
Many of the publicly available information materials are
specialized and designed to encourage specific actions by certain
groups, e.g., physicians, homebuilders, real estate agents, home
inspectors, home buyers and sellers, and many others. As a result, for
example, many home builders are voluntarily using radon resistant new
construction techniques and some real estate associations are
voluntarily incorporating the use of radon disclosure forms into their
regular business practices. Medical and health care professionals are
being educated about the health risks of radon and are encouraging
their patients to test their homes for radon as a preventive health
care measure. Public service announcements by local radio and TV
stations encourage the public to act. Other public information
materials provide consumers with information on how to test their homes
and what options they have for mitigating their radon problem.
Incentive programs and initiatives, such as free radon test kits,
and builder rebates when builders build homes radon-resistant, are
being implemented. States and local jurisdictions are also pursuing a
variety of regulatory radon initiatives, such as requiring schools to
be tested for indoor radon, requiring disclosure of elevated radon
levels in residential real estate transactions, and requiring new homes
to be built with radon-resistant new construction features through
building codes. These strategies and many others are being used to
successfully achieve public action to reduce the health risks from
indoor radon.
EPA has consulted with scientists, federal, state and local
government officials, public health organizations, risk communication
experts, and others to design this program and focus on radon program
strategies which have the greatest potential for reducing radon risks
through long-term institutional change. In developing strategies for
reducing radon risks, EPA and the States have learned from the
experience of other successful national public health campaigns, such
as the campaigns to promote the use of seat belts. These campaigns have
shown that significant public action to voluntarily
[[Page 59267]]
reduce health risks can be achieved from concerted efforts through a
variety of diverse strategies and through the combined efforts of State
and local governments, public health organizations, and other public
interest groups, grass roots organizations, and the private sector.
Program priorities have been identified to help concentrate and
focus efforts of EPA, the States, and local organizations, and others
on those activities that are most effective in achieving the overall
mission of indoor radon risk reduction. Working with a broad group of
stakeholders, EPA established several key priority areas for indoor
radon. States and cooperative national organizations have been focusing
many of their efforts and activities in these areas.
1. Targeting Efforts on the Greatest Risks First
EPA, the States, and many other public health organizations
recommend that all homes be tested and all homes at or above 4 pCi/L be
fixed. However, resources have been more heavily focused initially in
areas where action produces the most substantial risk reduction, such
as on homes and schools in the high radon potential areas and on the
increased risk of lung cancer from indoor radon to current and former
smokers.
2. Promote Radon-Resistant New Construction
EPA and others encourage programs to promote voluntary adoption of
radon-resistant building techniques by builders and the adoption of
radon construction standards into national, State and local building
codes. Methods (model standards) that establish construction techniques
for reducing radon entry in new construction have been developed and
published by EPA in collaboration with the National Association of Home
Builders. There are currently over 30 major building contractors (some
are national firms) who design and construct radon resistant new homes.
It is very cost-effective to build new homes radon-resistant,
especially in higher radon potential areas. In the existing indoor
radon program, EPA has been encouraging the States to promote testing
and mitigation in all areas of a State. EPA has also encouraged the
States to focus on their activities to promote radon-resistant new
construction on the highest radon potential areas (Zone 1) where
building homes radon-resistant is most cost-effective. However, it is
also cost-effective to build homes in medium potential areas (Zone 2),
as well as in ``hot'' spots found in most lower radon potential areas
(Zone 3).
3. Promote Testing and Mitigation During Real Estate Transactions
Based on the efforts of EPA, the States, and others, there has been
a steady increase in the number of radon tests and mitigations
voluntarily done through real estate actions. It is very cost-effective
to test and mitigate existing homes with elevated indoor radon levels.
Real estate transactions offer a significant opportunity to achieve
radon risk reduction. In 1993, EPA published the ``Home Buyer's and
Seller's Guide to Radon'' (USEPA 1993f). Hundreds of thousands of
copies of the ``Home Buyer's Guide'' have been distributed to
consumers. The companion to the ``Home Buyer's Guide'' is the
``Consumer's Guide to Radon Reduction'' (USEPA 1992d) which provides
information on how to go about reducing elevated radon levels in a
home.
A significant amount of radon testing and mitigation of existing
homes takes place during real estate transactions through the
combination of home inspections, real estate transfers, and relocation
services. Many different groups are in a position to influence buyers
and sellers to test and mitigate elevated radon levels. This includes
sales agents and brokers, buyers agents, home inspectors, mortgage
lenders, secondary mortgage lenders, appraisers, insurance companies,
State real estate licensing commissions, real estate educators,
relocation companies, real estate press, and others. There are
currently no requirements at the federal, State, or local level that a
house be tested for indoor radon as part of a real estate transaction.
Many State and local governments, however, have passed laws requiring
some form of radon disclosure, although the extent and detail of these
mandatory disclosure laws varies.
4. Promote Individual and Institutional Change through Public
Information and Outreach Programs
Because the health risk associated with indoor radon is controlled
primarily by individual citizens, EPA, the States and others have
developed a nationwide public information effort to inform the public
about the health risks from indoor radon and encourage them to take
action. EPA recommends that the public use EPA-listed or State-listed
radon test devices and hire a trained and qualified radon contractor to
fix elevated radon levels. Early on, EPA established voluntary programs
to evaluate the proficiency of these testing and mitigation service
companies to provide a mechanism for providing the public with
information by publishing updated lists of firms that pass all relevant
criteria. Many States have established their own proficiency programs.
To help support these efforts, EPA established four self-sustaining
Regional Radon Training Centers across the country to train testing and
mitigation contractors, State personnel, and others in radon
measurement, mitigation, and prevention techniques. In 1998, the
Conference of Radiation Control Program Directors (CRCPD), representing
State radiation officials, initiated a pilot program through the
National Environmental Health Association to establish a privatized
national proficiency program to replace EPA's proficiency program which
is terminating.
VII. What Are the Requirements for Addressing Radon in Water and
Radon in Air? MCL, AMCL and MMM
A CWS must monitor for radon in drinking water in accordance with
the regulations, as described in Section VIII of this preamble, and
report their results to the State. If the State determines that the
system is in compliance with the MCL of 300 pCi/L, the CWS does not
need to implement a MMM program (in the absence of a State program),
but must continue to monitor as required.
As discussed in Section VI, EPA anticipates that most States will
choose to develop a State-wide MMM program as the most cost-effective
approach to radon risk reduction. In this case, all CWSs within the
State may comply with the AMCL of 4000 pCi/L. Thus, EPA expects the
vast majority of CWSs will be subject only to the AMCL. In those
instances where the State does not adopt this approach, the proposed
regulation provides the following requirements:
A. Requirements for Small Systems Serving 10,000 People or Less
The EPA is proposing that small CWS serving 10,000 people or less
must comply with the AMCL, and implement a MMM program (if there is no
state MMM program). This is the cut-off level specified by Congress in
the 1996 Amendments to the Safe Drinking Water Act for small system
flexibility provisions. Because this definition does not correspond to
the definitions of ``small'' for small businesses, governments, and
non-profit organizations previously established under the RFA, EPA
requested comment on an alternative definition of ``small entity'' in
the preamble to the proposed
[[Page 59268]]
Consumer Confidence Report (CCR) regulation (63 FR 7620, February 13,
1998). Comments showed that stakeholders support the proposed
alternative definition. EPA also consulted with the SBA Office of
Advocacy on the definition as it relates to small business analysis. In
the preamble to the final CCR regulation (63 FR 4511, August 19, 1998),
EPA stated its intent to establish this alternative definition for
regulatory flexibility assessments under the RFA for all drinking water
regulations and has thus used it for this radon in drinking water
rulemaking. Further information supporting this certification is
available in the public docket for this rule.
EPA's regulation expectation for small CWSs is the MMM and AMCL
because this approach is a much more cost-effective way to reduce radon
risk than compliance with the MCL. (While EPA believes that the MMM
approach is preferable for small systems in a non-MMM State, they may,
at their discretion, choose the option of meeting the MCL of 300 pCi/L
instead of developing a local MMM program). The CWSs will be required
to submit MMM program plans to their State for approval. (See Sections
VI.A and F for further discussion of this approach).
SDWA Section 1412(b)(13)(E) directs EPA to take into account the
costs and benefits of programs to reduce radon in indoor air when
setting the MCL. In this regard, the Agency expects that implementation
of a MMM program and CWS compliance with 4000 pCi/L will provide
greater risk reduction for indoor radon at costs more proportionate to
the benefits and commensurate with the resources of small CWSs. It is
EPA's intent to minimize economic impacts on a significant number of
small CWSs, while providing increased public health protection by
emphasizing the more cost-effective multimedia approach for radon risk
reduction.
B. Requirements for Large Systems Serving More Than 10,000 People
The proposal requires large community water systems, those serving
populations greater than 10,000, to comply with the MCL of 300 pCi/L
unless the State develops a State-wide MMM program, or the CWSs
develops and implements a MMM program meeting the four regulatory
requirements, in which case large systems may comply with the AMCL of
4,000 pCi/L. CWSs developing their own MMM plans will be required to
submit these plans to their State for approval.
C. State Role in Approval of CWS MMM Program Plans
The SDWA provides that EPA will approve CWS MMM program plans. EPA
has developed criteria to be used for approving MMM programs. EPA will
review and approve State MMM program plans. CWS MMM program plans that
address the criteria and are approved by the State are deemed approved
by EPA. The proposed rule requires States that do not have a State-wide
MMM program, as a condition of primacy for the radon regulation, to
review MMM program plans submitted by CWSs and to approve plans meeting
the four criteria for MMM programs discussed in Section VI of this
preamble, including providing notice and opportunity for public comment
on CWS MMM program plans. Under Section 1412(b)(13)(G)(vi) of SDWA, MMM
program plans submitted by CWSs are to be subject to the same criteria
and conditions as State MMM program plans. EPA will review CWS MMM
program plans in non-primacy States, Tribes and Territories that do not
have a state-wide MMM program, and approve them if they meet the four
required criteria.
D. Background on Selection of MCL and AMCL
The SDWA directs that if the MCL for radon is set at a level more
stringent than the level in drinking water that would correspond to the
average concentration of radon in outdoor air, EPA must also set an
alternative MCL at the level corresponding to the average concentration
in outdoor air. Consistent with this requirement, EPA is proposing to
set the AMCL at 4000 pCi/L. This level is based on technical and
scientific guidance contained in the NAS Report (NAS 1999b) on the
water-to-air transfer factor of 10,000 pCi/L in water to 1 pCi/L in
indoor air and the average outdoor radon level of 0.4 pCi/L.
The SDWA generally requires that EPA set the MCL for each
contaminant as close as feasible to the MCLG, based on available
technology and taking costs to large systems into account. The 1996
amendments to the SDWA added the requirement that the Administrator
determine whether or not the benefits of a proposed maximum contaminant
level justify the costs based on the HRRCA required under Section
1412(b)(3)(C). They also provide new discretionary authority to the
Administrator to set an MCL less stringent than the feasible level if
the benefits of an MCL set at the feasible level would not justify the
costs (SDWA section 1412(b)(6)(A)).
EPA is proposing to set the MCL at 300 pCi/L, in consideration of
several factors. First, the Agency considered the general statutory
requirement that the MCL be set as close as feasible to the MCLG of
zero (SDWA section 1412(b)(4)), and its responsibility to protect
public health. In addition, the radon-specific provisions of the
amendments provide that, in promulgating a radon standard, the Agency
take into account the costs and benefits of programs to control indoor
radon (SDWA 1412(b)(13)(E). Although EPA believes that an MCL of 100
pCi/L would be feasible, EPA believes that consideration of the costs
and benefits of indoor radon control programs allows the level of the
MCL to be adjusted to a less stringent level than the Agency would set
using the SDWA feasibility test. The proposed MCL of 300 pCi/L takes
into account and relies on the unique conditions of this provision and
the reality it reflects that the great preponderance of radon risk is
in air, not water, and the much more cost-effective alternative to
water treatment is to address radon in indoor air through the MMM
program. The Agency recognizes that controlling radon in air will
substantially reduce human health risk in more cost-effective ways than
spending resources to control radon in drinking water. If most states
adopted the MMM/AMCL option, EPA estimates the combined costs for
treatment of water at systems exceeding the AMCL, developing a MMM
program, and implementing measures to get risk reduction equivalent to
national compliance with the MCL (62 avoided fatal cancer cases and 4
avoided non-fatal cancer cases per year) at $80 million, which is
substantially less than the $407.6 million cost of achieving the MCL.
EPA expects that most states will adopt the AMCL/MMM program option
While EPA believes it is appropriate to acknowledge the more cost-
effective control program to a certain extent in setting the MCL, the
Agency does not believe the cost-effectiveness is the sole determining
factor. Rather, EPA believes the absolute level of risk to which
members of the public may be exposed is also a key consideration in
determining a standard that is protective of public health.
The Agency proposed an MCL of 300 pCi/L in 1991 based, in part, on
its assessment of the health risk posed by radon in drinking water. It
should be noted that the overall magnitude of risk estimated by the
Agency at that time is in agreement with the overall risk of radon in
drinking water currently estimated by the National Academy of Sciences
(NAS 1999b). The Agency has
[[Page 59269]]
a long-standing policy that drinking water standards should limit risk
to within a range of approximately 10 -4 to 10 -6
and is thus proposing to use the flexibility provided by the authority
in 1412(b)(13)(E) to propose an MCL of 300 pCi/L, which is
approximately at the upper bound of the Agency's traditional risk range
used for the drinking water program (representing an estimated 2 fatal
cancers per 10,000 persons).
As noted earlier, the Administrator must publish a determination as
to whether the benefits of the proposed MCL justify the costs, based on
the Health Risk Reduction and Cost Analysis prepared in accordance with
SDWA Sec. 1412(b)(3)(C). Accordingly, the Administrator has determined
that the benefits of the proposed MCL of 300 pCi/L justify the costs.
The benefits of the proposed MCL, include about 62 avoided fatal lung
cancer cases and 4 avoided non-fatal lung cancer cases annually. EPA
has used a valuation of $5.8 million ($1997) to value the avoided fatal
cancers and a valuation of $536,000 ($1997) to value the avoided non-
fatal cancers. Multiplying these valuations by the estimated cancer
cases avoided (62 fatal, 3.6 non-fatal) yields a benefits estimate of
$362 million per year. The cost to achieve national compliance with an
MCL of 300 pCi/L is estimated at $407.6 million per year. EPA expects
the actual cost of the proposed rule to be significantly lower, since
the expectation is that most systems will not need to comply with the
MCL of 300 pCi/L. Costs would be about $80 million per year if the
AMCL/MMM option is widely adopted by States.
There are also some potential non-quantified benefits, including
customer peace of mind from knowing drinking water has been treated for
radon and reduced treatment costs for arsenic for some water systems
that have problems with both contaminants, and non-quantified costs,
including increased risks from exposure to disinfection byproducts,
permitting and treatment of radon off-gassing, anxiety on the part of
residents near treatment plants and customers who may not have
previously been aware of radon in their water, and safety measures
necessary to protect treatment plant personnel from exposure to
radiation. However, in this case it is not likely that accounting for
these non-quantifiable benefits and costs quantitatively would
significantly alter the overall assessment. Taking both quantified and
non-quantified benefits into account, EPA has determined that the costs
are justified by the benefits. Accordingly, the new authority to set a
less stringent MCL if benefits do not justify costs is not applicable
and has not been used in this proposal.
Although the central tendency estimate of monetized costs exceeds
the central tendency estimate of monetized benefits, the determination
that benefits justify costs is consistent with the legislative history
of this provision, which makes clear that this determination whether
benefits ``justify'' costs is more than a simple arithmetic analysis of
whether benefits ``exceed'' or ``outweigh'' costs. The determination
must also ``reflect the non-quantifiable nature of some of the benefits
and costs that may be considered. The Administrator is not required to
demonstrate that the dollar value of the benefits are greater (or
lesser) than the dollar value of the costs.'' [Senate Report 104-169 on
S. 1316, p. 33] The determination is based on the analysis conducted
under SDWA Sec. 1412(b)(3)(C), in the Health Risk Reduction and Cost
Analysis (HRRCA) published for public comment on February 26, 1999 (64
FR 9559), revised in response to public comment, and available as part
of the Regulatory Impact Analysis (1999n) in the public docket to
support this rulemaking. The costs and benefits of the proposed rule,
and the methodologies used to calculate them, are discussed in detail
in section XII of this preamble and in the Regulatory Impact Analysis
(1999n).
In making this determination, EPA also considered the special
nature of the radon standard, which provides an alternate MCL of 4000
pCi/L for states or water systems that adopt a MMM program designed to
produce equal or greater risk reduction benefits to compliance with the
MCL by promoting voluntary public action to mitigate radon in indoor
air. As noted previously, mitigation of radon in indoor air is much
more cost-effective than mitigation of radon in drinking water. If most
states adopted the MMM/AMCL option, EPA estimates the combined costs
for treatment of water at systems exceeding the AMCL, developing a MMM
program, and implementing measures to get risk reduction equivalent to
national compliance with the MCL (62 avoided fatal cancer cases and 4
avoided non-fatal cancer cases per year) at $80 million, which is
substantially less than the $407.6 million cost of achieving the MCL.
In its valuation of costs and benefits for the MMM program, EPA has
assumed that adopting the MMM approach will achieve only benefits
equivalent to those for meeting the MCL and has calculated the costs
and benefits of the proposed rule on this basis. However, EPA expects
that adoption of MMM programs will be widespread as a result of this
rule and that the actual benefits realized will be far greater than
those associated with meeting the MCL. In addition, EPA fully expects
most States to follow the MMM approach, therefore CWSs below the AMCL
will incur minimal costs and a much smaller subset of CWSs will incur
costs to meet the AMCL. Thus, costs for meeting the MCL are a
theoretical worst case scenario which the Agency believes will not
occur, particularly since the regulatory expectation for water systems
serving 10,000 people or fewer would be that they meet the 4000 pCi/L
AMCL, along with implementation of a local MMM program. Although in
some cases small CWSs may choose to meet the MCL of 300 pCi/L through
water treatment, this is voluntary and not a requirement of the
proposed regulation.
The Agency also considered the costs, benefits, and risk reduction
potential of radon levels at 100 pCi/l, 500 pCi/L, 1000 pCi/L, 2000
pCi/L and 4000 pCi/L. As table VII.1 illustrates, the costs and
benefits increase as the radon level increases. The quantified costs
somewhat exceed the quantified benefits at each level, but the benefit-
cost ratios are similar. However, the difference between costs and
benefits becomes somewhat larger as the various MCL options become more
stringent, with the largest difference at 100 pCi/L. When the
uncertainty of the estimates is factored in, there is overlap in the
benefit and cost estimates at all evaluated options. For more
information on this analysis, please refer to the Regulatory Impact
Analysis (RIA) for this proposal (USEPA, 1999n).
[[Page 59270]]
Table VII.1.--Evaluation of Radon Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cost per
Fatal fatal Total Monetized
Radon level (pCi/L) cancer Individual fatal lifetime cancer risk cancer case national benefits \1\ Benefit-
cases avoided costs \1\ $M cost ratio
avoided ($M) $M
--------------------------------------------------------------------------------------------------------------------------------------------------------
4000....................................... 2.9 26.8 in 10,000........................... 14.9 43.1 17.0 0.4
2000....................................... 7.3 13.4 in 10,000........................... 9.5 69.7 42.7 0.6
1000....................................... 17.8 6.7 in 10,000............................ 7.3 130.5 103 0.8
500........................................ 37.6 3.35 in 10,000........................... 6.8 257.4 219 0.9
300........................................ 62.0 2.0 in 10,000............................ 6.6 407.6 362 0.9
100........................................ 120.0 0.67 in 10,000........................... 6.8 816.2 702 0.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Water Mitigation only; assuming 100% compliance with MCL. Source: revised HRRCA.
Some commenters recommended that EPA give serious consideration to
setting an MCL at the AMCL level (4000 pCi/L), or at least at a level
substantially above 300 pCi/L, in order to control radon levels in
drinking water at a level more comparable to outdoor background levels.
This approach was also discussed by the Small Business Advocacy Review
Panel convened for this rule under the RFA as amended by SBREFA. (A
copy of the Panel's final report is available in the docket for this
rule making, (USEPA, 1998c).)
As noted earlier, EPA's interpretation of the standard-setting
requirements of the SDWA for radon are that they rely primarily upon
the general standard-setting provisions for National Primary Drinking
Water Regulations, with some additional radon-specific provisions. The
general provisions require that the MCL be set as close as feasible to
the MCLG. The radon-specific provisions direct the Administrator to
take into account the costs and benefits of control programs for radon
from other sources. As discussed, EPA is interpreting these general and
radon-specific authorities to propose an MCL above the feasible level,
near the upper end of the risk range traditionally used by the Agency
in setting drinking water standards. In addition, EPA believes that the
extensive statutory detail enacted on multimedia mitigation illustrates
a congressional preference for cost-effective compliance through the
AMCL/MMM program approach. EPA notes that the equal or greater risk
reduction required to be achieved through the AMCL/MMM option would be
diminished as the MCL approaches the AMCL of 4,000 pCi/L and that fewer
States and CWSs would select this option. Further, the AMCL/MMM
approach would be eliminated entirely if the MCL were set at the AMCL.
As noted previously, EPA believes the proposed MCL of 300 pCi/L, in
combination with the proposed AMCL and MMM approach, accurately and
fully reflects the SDWA provisions. The Agency recognizes , however,
that some stakeholders may have strong views about the appropriateness
of setting an MCL at a higher level. Accordingly, EPA requests comment
on the option of setting the MCL closer to or at the AMCL level of 4000
pCi/L. In this connection, the Agency also requests comments on and the
rationale for how such alternative options could be legally supported
under the SDWA and in the record for this rulemaking, in light of the
considerations EPA has applied for the MCL it proposes.
EPA solicits comment on the proposed MCL and AMCL and the Agency's
rationale, and on other appropriate MCLs given these considerations,
and the rationale for alternative levels. In the final rule, the Agency
may select a higher or lower option from those analyzed in the HRRCA
for the final radon rule without further public comment.
E. Compliance Dates
The proposed time line for compliance with the radon rule is
described next and illustrated in Figure VII.1.
BILLING CODE 6560-60-P
[[Page 59271]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.002
BILLING CODE 6560-50-C
[[Page 59272]]
States are required to submit their primacy revision application
packages by two years from the date of publication of the final rule in
the Federal Register. For States adopting the AMCL, EPA approval of a
State's primacy revision application is contingent on submission of and
EPA approval of the State's MMM program plan. Therefore, EPA is
proposing to require submission of State-wide MMM program plans as part
of the complete and final primacy revision application. This will
enable EPA to review and approve the complete primacy application in a
timely and efficient manner in order to provide States with as much
time as possible to begin to implement MMM programs. In accordance with
Section 1413(b)(1) of SDWA and 40 CFR 142.12(d)(3), EPA is to review
primacy applications within 90 days. Therefore, although the SDWA
allows 180 days for EPA review and approval of MMM program plans, EPA
expects to review and approve State primacy revision applications for
the AMCL, including the State-wide MMM program plan, within 90 days of
submission to EPA.
EPA is proposing that CWSs begin their initial monitoring
requirements (one year of quarterly monitoring) for radon by 3 years
after publication of the final rule in the Federal Register, except for
CWSs in States that submit a letter to the Administrator committing to
develop an MMM program plan in accordance with Section 1412
(b)(13)(G)(v). For CWSs in these States, one year of quarterly
monitoring is proposed to begin 4.5 years after publication of the
final rule. The proposed rule allows systems to use grandfathered data
collected after the proposal date to satisfy the initial monitoring
requirements provided the monitoring and analytical methods employed
satisfy the regulations set forth in the rule and the State approves.
Systems opting to conduct early monitoring will not be considered in
violation of the MCL/AMCL until after the initial monitoring period
applicable to their State (i.e., 4 years after publication of the final
rule, 5.5 years after publication of the final rule).
The routine and reduced monitoring requirements were developed to
be consistent with the Standardized Monitoring Framework (SMF) and the
Phase II/V monitoring schedule. EPA believes this is valuable for
States and systems by providing sampling efficiency and organization,
therefore, EPA has tried to adapt the compliance dates so that States
and systems can make a smooth transition into the SMF following the
initial monitoring requirements. The necessity to complete the initial
monitoring in a timely manner is driven by the need for systems in non-
MMM States to evaluate their compliance options, including development
of a local MMM program and compliance with the AMCL), and for systems
in MMM States to ensure compliance with the AMCL.
EPA feels it is important to set time constraints on implementation
of the MMM plans to ensure the equal or greater risk reduction
resulting from multimedia mitigation. Therefore, the rule must allow
the systems in non-MMM States enough time to develop their MMM program
plan with technical assistance from the State and submit the plan for
State approval. In addition, the State must have sufficient time to
review and approve the local plans. If the compliance determination for
a system in a non-MMM State exceeds the MCL during the initial
monitoring period, the proposed rule requires these systems to notify
the State of their intention to develop a local MMM program at the
completion of initial monitoring, 4 years after publication of the
final rule. The local MMM program plans must be submitted to the State
for approval by 5 years after of publication of the final rule (i.e.,
12 months after the completion of initial monitoring) and the States
have 6 months from the submittal date to review and approve or
disapprove the plan. The system will begin implementation of their MMM
program 5.5 years after publication of the final rule (i.e., 1.5 years
after the completion of initial monitoring). If the State fails to
review and disapprove the local MMM program in the time allowed, the
system will begin implementation of the submitted plan. If the system
fails to comply with these compliance dates, a MCL violation will apply
from the date of exceedence. If the compliance determination for a
system choosing to comply with the MCL exceeds the MCL following the
completion of the initial monitoring period, the system will have the
option to submit a local MMM plan to the State within 1 year from the
date of the exceedence and begin implementation 1.5 years from the date
of the exceedence or incur a MCL violation.
Implementation of State-wide MMM programs must begin 3 years after
publication of the final rule, unless the State submits a letter to the
Administrator committing to develop an MMM program plan in accordance
with Section 1412 (b)(13)(G)(v) of the SDWA. States submitting this
letter must implement their State-wide MMM program plan by 4.5 years
after publication of the final rule. EPA feels it is extremely
important that the MMM program plans be completed on a schedule that
allows States sufficient time to begin implementation by the compliance
date to ensure that equal or greater risk reduction benefits are
provided.
EPA recognizes potential issues may arise as a result of the
proposed initial monitoring schedule. The potential issues include lab
capacity and a temporary deviation from the SMF schedule. EPA is
requesting comment on alternatives to avoid or lessen the impact of
these issues and other issues not listed here.
EPA considers the proposed monitoring schedule to be acceptable
since the proposed rule affects one contaminant and applies to a
smaller universe of water systems (NTNCWSs, transient systems, and CWSs
relying solely on surface water are not covered by the rule) which
decreases the number of systems effected, and therefore lessens the
impacts of the potential issues. An alternative initial monitoring
scenario which was considered would specify early monitoring
requirements for systems serving more than 10,000 people. This scenario
would put additional burden on the States and systems to monitor early
and it would not substantially ease the workload since the number of
systems serving greater than 10,000 that use groundwater or groundwater
under the direct influence of surface water is relatively small.
Initial monitoring could be phased in over a period of two or three
years, but EPA does not feel it is appropriate to extend the initial
monitoring period due to the necessity to evaluate the need to develop
and implement local MMM program plans. In MMM States, systems must be
in compliance with the AMCL in a timely manner to ensure the maximum
risk reduction.
In consideration of all these factors, EPA is proposing to require
the initial monitoring over a one-year period as specified earlier.
However, systems opting to conduct early monitoring will not be
considered in violation of the MCL/AMCL until after the initial
monitoring period applicable to their State (i.e., 4 years after
publication of the final rule, 5.5 years after publication of the final
rule). However, CWSs opting to conduct early monitoring will not be
considered in violation of the MCL/AMCL until after the initial
monitoring period applicable to their State (i.e., 4 years after
publication of the final rule, 5.5 years after publication of the final
rule. It is EPA's strong recommendation that all States choose to adopt
the AMCL and implement an MMM
[[Page 59273]]
program. But some States may elect to adopt the MCL or may decide later
to adopt the AMCL/MMM approach. In these states, the initial monitoring
will be required to begin by 3 years after publication of the final
rule, whereas in States submitting the 90-day letter committing to
develop an MMM program plan will begin initial monitoring 4.5 years
after publication of the final rule.
VIII. What Are the Requirements for Testing for and Treating Radon
in Drinking Water?
A. Best Available Technologies (BATs), Small Systems Compliance
Technologies (SSCTs), and Associated Costs
1. Background
Section 1412(b)(4)(E) of the Act states that each national primary
drinking water regulation which establishes an MCL shall list the
technology, treatment techniques, and other means which the
Administrator finds to be feasible for purposes of meeting the MCL. In
addition, the Act states that EPA shall list, if possible, affordable
small systems compliance technologies (SSCTs) that are feasible for the
purposes of meeting the MCL. In order to fulfill these requirements,
EPA has identified best available technologies (BAT) and SSCTs for
radon.
(a) Proposed BAT. Technologies are judged to be BAT when they are
able to satisfactorily meet the criteria of being capable of high
removal efficiency; having general geographic applicability, reasonable
cost, and a reasonable service life; being compatible with other water
treatment processes; and demonstrating the ability to bring all of the
water in a system into compliance. The Agency proposes that, of the
technologies capable of removing radon from source water, only aeration
fulfills these requirements of the SDWA for BAT determinations for this
contaminant. The full range of technical capabilities for this proposed
BAT is discussed in the EPA Technologies and Costs document for radon
(USEPA 1999h). Table VIII.A.1 summarizes the BAT findings by EPA for
the removal of the subject drinking water contaminants, including a
summary of removal capabilities.
Table VIII.A.1--Proposed Bat and Associated Contaminant Removal
Efficiencies
------------------------------------------------------------------------
------------------------------------------------------------------------
High Performance Aeration \1\............ Up to 99.9% Removal.
------------------------------------------------------------------------
Note: (1) High Performance Aeration is defined as the group of aeration
technologies that are capable of being designed for high radon removal
efficiencies, i.e., Packed Tower Aeration, Multi-Stage Bubble Aeration
and other suitable diffused bubble aeration technologies, Shallow Tray
and other suitable Tray Aeration technologies, and any other aeration
technologies that are capable of similar high performance.
Granular activated carbon (GAC) can also remove radon from water,
and was evaluated as a potential BAT and a potential small systems
compliance technology for radon. Since GAC removes radon less
efficiently than it does organic contaminants, it generally requires
designs that use larger quantities of carbon per volume of water
treated to remove radon compared to contaminants for which GAC is BAT.
This requirement for larger carbon amounts translates to much higher
treatment costs for GAC radon removal. In fact, full-scale application
of GAC for radon removal has been limited to installations at the
household point-of-entry and for centralized treatment for very small
communities (AWWARF 1998a). EPA has determined that the requirements
for radon removal render it infeasible for large municipal treatment
systems, and it is therefore not considered a BAT for radon. However,
GAC and point-of-entry (POE) GAC may be appropriate for very small
systems under some circumstances, as described next (USEPA 1999h,
AWWARF 1998a, AWWARF 1998b).
(b) Proposed Small Systems Compliance Technologies. The 1996
Amendments to SDWA recognize that BAT determinations may not address
many of the problems faced by small systems. In response to this
concern, the Act specifically requires EPA to make technology
assessments relevant to the three categories of small systems
respectively for both existing and future regulations. These
requirements are in addition to EPA's obligation, unchanged by the SDWA
as amended in 1996, to designate BAT. The three population-served size
categories of small systems defined by the 1996 SDWA are: 10,000--3,301
persons, 3,300--501 persons, and 500--25 persons. These evaluations
include assessments of affordability and technical feasibility of
treatment technologies for each class of small system. Table VIII.A.2,
``Proposed Small Systems Compliance Technologies (SSCTs) and Associated
Contaminant Removal Efficiencies'', lists the proposed small systems
compliance technologies for radon and summarizes EPA's findings
regarding affordability and technical feasibility for the evaluated
technologies. EPA has interpreted the SSCTs as equivalent to BATs under
Section 1415 of the Act, for the purposes of small systems (those
serving 10,000 persons or fewer) applying to primacy agencies for
Section 1415(a) variances.
Table VIII.A.2.-- Proposed Small Systems Compliance Technologies (SSCTS) \1\ and Associated Contaminant Removal
Efficiencies
----------------------------------------------------------------------------------------------------------------
Affordable listed Limitations
Small systems compliance small systems Removal efficiency Operator level (see
technology categories \2\ required \3\ footnotes)
----------------------------------------------------------------------------------------------------------------
Packed Tower Aeration (PTA)..... All Size Categories 90- > 99.9% Removal Intermediate........ (a)
High Performance Package Plant All Size Categories 90- > 99.9% Removal Basic to (a)
Aeration (e.g., Multi-Stage Intermediate.
Bubble Aeration, Shallow Tray
Aeration).
Diffused Bubble Aeration........ All Size Categories 70 to > 99% removal Basic............... (a, b)
Tray Aeration................... All Size Categories 80 to > 90%........ Basic............... (a, c)
Spray Aeration.................. All Size Categories 80 to > 90%........ Basic............... (a, d)
Mechanical Surface Aeration..... All Size Categories > 90%.............. Basic............... (a, e)
Centralized granular activated May not be 50 to > 99% Removal Basic............... (f)
carbon. affordable, except
for very small
flows.
[[Page 59274]]
Point-of-Entry (POE) granular May be affordable 50 to > 99% Removal Basic............... (f, g)
activated carbon. for systems
serving fewer than
500 persons..
----------------------------------------------------------------------------------------------------------------
Notes: \1\ The Act (Section 1412(b)(4)(E)(ii)) specifies that SSCTs must be affordable and technically feasible
for small systems.
\2\ This section specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501,
(ii) those serving more than 500, but fewer than 3,301, and (iii) those serving more than 3,300, but fewer
than 10,001.
\3\ From National Research Council. Safe Water from Every Tap: Improving Water Service to Small Communities.
National Academy Press. Washington, DC. 1997.
Limitations: (a) Pre-treatment to inhibit fouling may be needed. Post-treatment disinfection and/or corrosion
control may be needed.
(b) May not be as efficient as other aeration technologies because it does not provide for convective movement
of the water, which reduces the air:water contact. It is generally used in adaptation to existing basins.
(c) Costs may increase if a forced draft is used. Slime and algae growth can be a problem, but may be controlled
with chemicals, e.g., copper sulfate or chlorine.
(d) In single pass mode, may be limited to uses where low removals are required. In multiple pass mode (or with
multiple compartments), higher removals may be achieved.
(e) May be most applicable for low removals, since long detention times, high energy consumption, and large
basins may be required for larger removal efficiencies.
(f) Applicability may be restricted to radon influent levels below around 5000 pCi/L to reduce risk of the build-
up of radioactive radon progeny. Carbon bed disposal frequency should be designed to allow for standard
disposal practices. If disposal frequency is too long, radon progeny, radium, and/or uranium build-up may make
disposal costs prohibitive. Proper shielding may be required to reduce gamma emissions from the GAC unit. GAC
may be cost-prohibitive except for very small flows.
(g) When POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and
monitoring must be provided by the water system to ensure adequate performance.
(c) Approaches for Listing Small Systems Compliance Technologies
(SSCTs). EPA has considered several options for the listing of SSCTs in
the proposed rule for radon. The issue is how to list SSCTs with BAT in
the rule, while at the same time allowing for flexible and timely
updates to the list of SSCTs in the future.
EPA would like to establish a procedure that allows SSCT lists to
be updated by guidance, rather than through the more resource intensive
and time-consuming process of rule-making. For example, under today's
proposal, EPA is including SSCT lists in the rule. This approach fully
satisfies the requirements in Section 1412(b)(4)E(ii) of the Act, which
states that EPA shall include SSCTs in lists of BAT for meeting the
MCL. Since BATs are explicitly listed in rules, it is consistent to
explicitly list SSCTs. Also, Section 1415(a) of the Act requires that
BAT be proposed and promulgated with NPDWRs to satisfy the provisions
for ``general variances'' (variances under Section 1415(a)); therefore,
SSCTs must be listed in the rule if small systems are to be allowed to
use them as BAT in satisfying the provisions for general variances.
Regarding updates to the list of SSCTs, Section 1412(b)(9) of the
Act states that EPA shall review and revise, as appropriate, all
promulgated NPDWRs every six years. However, since revisions of NPDWRs
follow the normal rule-making process of proposing, taking public
comment, and finalizing the rule, the process can be very time-
consuming. While EPA believes that this six year review cycle is
sufficient for updates to lists of BAT, it is unlikely to be sufficient
for updates to lists of SSCTs, since recent improvements in package
plant technologies, POE/POU devices, and remote monitoring/control
technologies have been fairly rapid and future improvements seem
imminent. For this reason, EPA seeks comment on this approach or
alternate approaches that would allow for more timely updates to the
list of SSCTs.
In support of an approach to SSCT list updates that is less formal
and more expeditious than rulemaking, EPA notes that new Section
1412(b)(4)(E)(iv) allows the Administrator, after promulgating an
NPDWR, to ``supplement the list of technologies describing additional
or new or innovative treatment technologies that meet the requirements
of this paragraph for categories of small public water systems.'' This
provision does not contain any reference to or require rulemaking to
update the SSCT list, in contrast with the earlier 1994 House version
(in H.R. 3392) of this provision that specifically required revisions
of the list to be made ``by rule.''
Under one alternative, EPA would publish only an initial list of
SSCTs with the BAT list in 40 CFR 141.66. EPA would also state in the
rule that updates to the list of SSCTs would be done through guidance
published in the Federal Register or through updates to the SSCT
guidance manual. This process would be consistent with the process
already used for listing SSCTs for the currently regulated drinking
water contaminants (USEPA 1998g). A similar alternative approach would
simply ``list'' SSCTs in Section 141.66 by referencing EPA guidance,
which would be published separately and which could be updated
periodically as needed outside of the normal rule-making process.
Finally, EPA could publish both the initial list and the updates solely
in a Federal Register notice or as guidance; however, under this last
approach, only the promulgated BAT listed in the rule (which would not
include SSCTs) would be available for small systems seeking a general
variance under Section 1415(a) of the Act. EPA solicits comments on the
suggested approaches for the listing of SSCTs and on the equivalency of
SSCTs with BAT for the purposes of small systems applying for variances
under Section 1415 of the Act.
(d) Small Systems Affordability Determinations. The affordability
determinations that are used for listing SSCTs are discussed in detail
in recent EPA publications (USEPA 1998i, USEPA 1998e). It should be
noted that aeration is one of the least expensive treatment
technologies for drinking water (USEPA 1993d, NRC 1997) and has been
determined to be affordable for all three small systems size
categories. For the smallest size category (serving 25 to 500 persons),
EPA cost estimates indicate that typical annual household
[[Page 59275]]
costs for aeration (80% removal efficiency, with disinfection and
scaling inhibitor) are $190 per household per year ($/HH/yr). For
systems installing aeration only, household costs for the smallest
system size category are $114 per household per year. Case studies
(n=9, USEPA 1999h) for systems with aeration serving between 25 and 500
persons showed annual household costs ranging from $5 to $97 per
household per year, with an average of $45 per household per year.
Costs reported in these case studies included all pre- and post-
treatments added with aeration. The ``national average per household
cost'' estimated in the Regulatory Impact Analysis is $260 per
household per year for 25-500 persons. This average per household cost
is higher than the estimated per household costs for systems using
aeration since these average costs include not only aeration, but also
the more expensive compliance alternatives (GAC, regionalization, and
``high side'' PTA). Note that the cost for the 25-500 category is a
weighted average of the per household costs for the 25-100 and 101-500
categories reported in Table 7-2 of the Regulatory Impact Analysis.
Also note that monitoring costs of approximately $4.00 per household
per year ($270 per system) are included in the national average per
household costs, but not in the aeration treatment per household costs
reported.
Granular activated carbon (GAC) may be affordable only for very
small flows. EPA's GAC-COST model estimates indicate that GAC may not
be affordable for the smallest size category (25-500 persons served) in
whole. Annual household costs are estimated to be approximately $800 to
> $1000 per household per year. However, case studies of small systems
using GAC to remove radon for very small flows (populations served < 100="" persons)="" show="" annual="" household="" costs="" ranging="" from="" $46="" to="" $77="" per="" household="" per="" year.="" the="" large="" discrepancy="" between="" modeled="" costs="" and="" full-scale="" case="" study="" costs="" is="" probably="" due="" to="" the="" fact="" that="" the="" model="" design="" assumptions="" are="" more="" typical="" of="" larger="" systems,="" whereas="" the="" designs="" used="" in="" the="" case="" studies="" are="" much="" simpler.="" the="" american="" water="" works="" association="" research="" foundation="" (awwarf="" 1998a)="" similarly="" concludes="" that="" epa's="" cost="" estimates="" for="" radon="" removal="" by="" gac="" are="" over-="" estimates="" (ibid.,="" p.="" 190)="" and="" that="" gac="" can="" be="" cost="" competitive="" with="" aeration="" for="" very="" small="" systems="" (ibid.,="" chapter="" 8).="" examples="" of="" estimates="" of="" poe-gac="" capital="" costs="" are="" shown="" in="" the="" next="" section,="" ``treatment="" costs''.="" 2.="" treatment="" costs:="" bat,="" small="" systems="" compliance="" technologies,="" and="" other="" treatment="" (a)="" modeled="" treatment="" unit="" costs.="" total="" production="" costs="" associated="" with="" the="" various="" technological="" options="" for="" radon="" reduction,="" such="" as="" packed="" tower="" aeration="" and="" diffused="" bubble="" aeration="" installations,="" have="" been="" examined="" (usepa="" 1999h).="" for="" systems="" that="" are="" currently="" disinfecting,="" ninety-nine="" percent="" reduction="" of="" radon="" by="" pta="" is="" estimated="" to="" cost="" from="" $2.48/kgal="" (dollars="" per="" 1,000="" gallons="" treated)="" for="" the="" smallest="" systems,="" defined="" as="" those="" serving="" 100="" persons="" or="" fewer,="" to="" $="" 0.12/kgal="" for="" large="" systems,="" defined="" as="" those="" serving="" up="" to="" 1,000,000="" persons.="" eighty="" percent="" reduction="" of="" radon="" by="" pta="" without="" disinfection="" is="" estimated="" to="" range="" from="" $2.10/kgal="" to="" $0.08/kgal="" for="" the="" same="" system="" sizes.="" for="" those="" systems="" adding="" disinfection="" because="" of="" the="" addition="" of="" aeration="" treatment,="" disinfection="" treatment="" costs="" for="" very="" small="" systems="" are="" estimated="" at="" an="" additional="" $1.40/kgal="" and="" costs="" for="" large="" systems="" are="" estimated="" at="" an="" additional="" $0.07/kgal.="" aeration="" production="" costs="" have="" been="" adjusted="" to="" include="" costs="" that="" account="" for="" the="" addition="" of="" a="" chemical="" stabilizer="" (orthophosphate)="" by="" 25="" percent="" of="" small="" systems="" (those="" serving="" 10,000="" persons="" or="" fewer)="" and="" by="" 15="" percent="" of="" large="" systems.="" in="" other="" words,="" the="" production="" costs="" shown="" are="" weighted="" averages="" that="" simulate="" the="" installation="" of="" aeration="" without="" chemical="" stabilizers="" by="" a="" fraction="" of="" the="" systems="" and="" with="" chemical="" stabilizers="" by="" the="" remaining="" fraction.="" chemical="" stabilizers="" are="" used="" to="" minimize="" fouling="" from="" iron="" and="" manganese="" and/or="" to="" reduce="" corrosivity="" to="" the="" distribution="" system.="" chemical="" addition="" cost="" estimates="" include="" capital="" costs="" for="" feed="" systems="" and="" operations="" and="" maintenance="" costs="" for="" the="" processes="" involved.="" table="" vii.a.3="" summarizes="" total="" production="" costs="" for="" system="" size="" categorizes="" for="" 80="" percent="" radon="" removal.="" further="" details="" on="" costing="" assumptions="" and="" breakdown="" of="" the="" unit="" treatment="" costs="" can="" be="" found="" in="" the="" ria="" (usepa="" 1999h).="" table="" viii.a.3.--total="" production="" cost\1\="" of="" contaminant="" removal="" by="" bat="" for="" 80="" percent="" radon="" removal="" (dollars/="" 1,000="" gallons,="" late="" 1997="" dollars)="" ----------------------------------------------------------------------------------------------------------------="" population="" served="" ---------------------------------------------------------------------------------="" 25-100="" 100-500="" 500-1,000="" 1,000-3,300="" 3,300-10,000="">10,000
----------------------------------------------------------------------------------------------------------------
Aeration\2\................... 2.06 0.71 0.39 0.22 0.15 0.08-0.10
Aeration + disinfection....... 3.44 1.09 0.69 0.40 0.22 0.09-0.12
Granular Activated Carbon 0.34 2.16 2.16 NA NA NA
(GAC).
GAC + disinfection............ 1.71 2.54 2.46 NA NA NA
POE GAC + UV disinfection..... 16.99 14.03 NA NA NA NA
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Cost ranges are estimated from cost equations found in the radon Technologies and Costs document (EPA
1999h), as used in the radon HRCCA (64 FR 9559).
\2\ Aeration costs are weighted to include chemical inhibitor costs (Fe/Mn and corrosion control) for 25 percent
of small systems and 15 percent of large systems.
(b) Case Studies of Treatment Unit Costs. Case studies for aeration
and GAC are reported in detail in the radon Technologies and Costs
document (USEPA 1999h). Total production costs for aeration case
studies ranged from an average of $0.82/kgal for systems serving 25--
100 persons (n = 4, standard deviation = $0.32/kgal, average population
= 58) to $0.19/kgal for systems serving 100--3,300 persons (n = 11,
standard deviation = $0.22/kgal, average population = 873). Total
production costs for GAC ranged from $1.50/kgal for systems serving
fewer than 100 persons (n = 2, standard deviation = $0.48/kgal, average
population = 55) to $0.40/kgal for a system serving approximately
23,000 persons. Production costs for two POE GAC installations ranged
from $0.21/
[[Page 59276]]
kgal to $0.75/kgal. It should be noted that these POE GAC costs do not
include the additional monitoring costs that would apply in a
compliance situation. Annual monitoring costs are generally negligible
compared to annual treatment costs for centralized treatment (<2.5 percent="" for="" very="" small="" systems="" to=""><1 percent="" for="" large="" systems),="" and="" may="" be="" significant="" in="" the="" case="" of="" poe="" treatment="" (usepa="" 1998g).="" for="" this="" reason,="" the="" poe="" gac="" case="" study="" production="" costs="" may="" under-estimate="" true="" poe="" gac="" costs.="" in="" general,="" the="" case="" studies="" suggest="" that="" epa's="" modeled="" unit="" costs="" may="" be="" conservative="" for="" small="" systems.="" since="" it="" is="" true="" that="" the="" radon="" case="" studies="" are="" not="" necessarily="" a="" random="" sample="" of="" all="" systems="" that="" will="" be="" impacted="" by="" the="" future="" radon="" rule,="" it="" may="" be="" argued="" that="" the="" typical="" reported="" costs="" may="" differ="" significantly="" from="" the="" typical="" costs="" of="" compliance.="" however,="" the="" costs="" of="" aeration="" from="" the="" radon="" case="" studies="" overlap="" nicely="" with="" the="" costs="" reported="" in="" the="" vocs="" case="" studies,="" which="" should="" represent="" typical="" costs="" of="" compliance.="" given="" this="" fact="" and="" the="" large="" number="" of="" case="" studies="" used,="" epa="" has="" confidence="" that="" the="" case="" studies="" represent="" a="" best="" estimate="" of="" costs="" of="" treatment="" for="" compliance="" purposes.="" it="" should="" be="" noted="" that="" these="" reported="" case="" study="" costs="" are="" total="" costs="" and="" include="" all="" pre-="" and="" post-treatments="" added="" with="" the="" radon="" treatment="" process.="" (c)="" treatment="" cost="" assumptions="" and="" methodology.="" the="" general="" assumptions="" used="" to="" develop="" the="" treatment="" costs="" include="" costs="" for:="" chemicals="" and="" general="" maintenance,="" labor,="" capital="" amortized="" over="" 20="" years="" at="" a="" 7="" percent="" interest="" rate,="" equipment="" housing,="" associated="" engineering="" and="" construction,="" land="" for="" small="" systems="" (design="" flow="">< 1="" mgd="" per="" well),="" and="" power="" and="" fuel="" (usepa="" 1998h,="" usepa="" 1998g,="" usepa="" 1999h).="" costs="" were="" updated="" to="" december="" 1997="" dollars="" using="" a="" standard="" construction="" cost="" index="" (engineering="" news-record="" construction="" cost="" index).="" process="" capital="" costs="" for="" aeration="" technologies="" were="" calculated="" using="" updated="" cost="" equations="" from="" the="" packed="" tower="" column="" air="" stripping="" cost="" model="" (usepa="" 1993e).="" process="" capital="" costs="" for="" granular="" activated="" carbon="" and="" total="" capital="" costs="" for="" iron="" and="" manganese="" sequestration/="" corrosion="" control,="" and="" disinfection="" were="" calculated="" using="" standard="" epa="" models="" (as="" described="" in="" usepa="" 1998e="" and="" usepa="" 1999a).="" construction,="" engineering,="" land,="" permitting,="" and="" labor="" costs="" were="" estimated="" based="" upon="" recommendations="" from="" an="" expert="" panel="" comprised="" of="" practicing="" water="" design="" and="" costing="" engineers="" from="" professional="" consulting="" companies,="" utilities,="" state="" and="" federal="" agencies,="" and="" public="" utility="" regulatory="" commissions="" (usepa="" 1998i).="" gac="" disposal="" costs="" are="" included="" in="" the="" gac-="" cost="" o&m="" model.="" all="" cost="" estimates="" include="" capital="" costs="" for="" equipment="" housing="" and="" land="" for="" small="" systems="" (design="" flows="">< 1.0="" mgd).="" it="" was="" assumed="" that="" all="" treatment="" installations="" would="" include="" disinfection.="" capital="" and="" operating="" &="" maintenance="" costs="" for="" iron="" and="" manganese="" (fe/="" mn)="" sequestration="" by="" the="" addition="" of="" zinc="" orthophosphate="" were="" included="" for="" 25="" percent="" of="" small="" systems="" and="" 15="" percent="" of="" large="" systems.="" pre-="" and="" post-treatment="" assumptions="" are="" explained="" in="" more="" detail="" later.="" (d)="" ``decision="" tree''.="" compliance="" costs="" were="" estimated="" assuming="" that="" non-compliant="" water="" systems="" would="" choose="" from="" a="" variety="" of="" compliance="" options,="" including="" installing="" a="" suitable="" treatment="" train,="" finding="" an="" alternate="" source="" of="" water,="" purchasing="" water="" from="" a="" near-by="" water="" utility,="" and="" using="" best="" management="" practices,="" like="" blending="" or="" ventilated="" storage.="" the="" modeled="" proportions="" of="" systems="" choosing="" a="" compliance="" pathway="" (the="" ``decision="" tree'')="" is="" based="" on="" the="" assumption="" that="" systems="" will="" choose="" the="" most="" cost-effective="" alternative,="" given="" the="" fact="" that="" site-specific="" factors="" (e.g.,="" a="" well="" located="" in="" a="" suburban="" residential="" area)="" may="" force="" some="" systems="" to="" choose="" an="" option="" that="" is="" more="" expensive="" than="" the="" least="" cost="" alternative.="" the="" modeled="" proportions="" were="" assumed="" to="" vary="" by="" system="" size="" and="" water="" quality.="" more="" details="" on="" these="" assumptions="" are="" found="" in="" the="" health="" risk="" reduction="" and="" cost="" analysis="" supporting="" this="" proposal="" (64="" fr="" 9559).="" (e)="" iron="" and="" manganese="" assumptions.="" treatment="" costs="" assume="" that="" 25="" percent="" of="" small="" systems="" and="" 15="" percent="" of="" large="" systems="" installing="" aeration="" will="" need="" to="" add="" an="" additional="" chemical="" inhibitor="" (e.g.,="" orthophosphate,="" polyphosphates,="" silicates,="" etc.)="" to="" minimize="" the="" formation="" of="" iron/manganese="" (fe/mn)="" precipitates="" and="" carbonate="" scale;="" to="" reduce="" bio-fouling="" from="" the="" growth="" of="" fe/mn="" oxidizing="" bacteria="" (see,="" e.g.,="" faust="" and="" aly="" 1998);="" and="" to="" reduce="" water="" corrosivity.="" although="" zinc="" orthophosphate="" was="" assumed="" to="" be="" universally="" used,="" this="" was="" done="" as="" a="" simplifying="" costing="" assumption,="" and="" should="" not="" interpreted="" as="" suggesting="" that="" zinc="" orthophosphate="" is="" the="" appropriate="" inhibitor="" choice="" for="" all="" circumstances.="" uncertainty="" analyses="" were="" performed="" in="" national="" cost="" estimates="" to="" simulate="" a="" range="" of="" choices="" of="" chemical="" inhibitors="" by="" systems="" and="" to="" simulate="" a="" range="" in="" the="" percentages="" of="" systems="" requiring="" the="" addition="" of="" an="" inhibitor.="" it="" is="" reiterated="" that,="" for="" the="" purposes="" of="" iron/manganese="" control="" and="" corrosion="" control,="" other="" chemical="" inhibitors="" may="" be="" more="" appropriate="" than="" zinc="" orthophosphate="" on="" a="" case="" by="" case="" basis.="" (f)="" iron="" and="" manganese="" occurrence.="" tables="" viii.a.4="" and="" viii.a.5="" show="" the="" estimated="" co-occurrence="" of="" radon="" with="" dissolved="" iron="" and="" manganese="" in="" raw="" ground="" water="" for="" various="" radon="" and="" fe/mn="" levels.="" it="" can="" be="" seen="" from="" these="" tables="" (based="" on="" the="" u.s.="" geological="" survey's="" national="" water="" information="" system="" database,="" ``nwis'')="" that="" the="" majority="" of="" ground="" water="" systems="" will="" be="" expected="" to="" have="" fe/mn="" source="" water="" levels="" below="" the="" secondary="" mcls="" (smcls)="" for="" iron="" (greater="" than="" 85="" percent="" of="" gw="" samples="" have="" less="" than="" the="" smcl="" of="" 0.3="" mg/l)="" and="" manganese="" (greater="" than="" 75="" percent="" of="" gw="" systems="" have="" less="" than="" the="" smcl="" of="" 0.05="" mg/l).="" since="" fe/mn="" precipitation="" inhibitors="" are="" appropriate="" for="" treating="" combined="" fe/mn="" levels="" up="" to="" around="" 1-2="" mg/l="" (faust="" and="" aly="" 1998,="" usepa="" 1999h),="" this="" data="" indicates="" that="" the="" vast="" majority="" of="" ground="" water="" systems="" (greater="" than="" 95="" percent)="" will="" be="" expected="" to="" be="" in="" situations="" where="" inhibitors="" are="" sufficient="" for="" handling="" iron="" and="" manganese="" problems.="" the="" cost="" estimates="" conservatively="" assume="" that="" inhibitors="" will="" also="" be="" used="" by="" systems="" with="" source="" water="" below="" the="" smcls="" for="" iron="" and="" manganese.="" systems="" with="" fe/mn="" levels="" above="" 1-2="" mg/l="" may="" require="" oxidation/filtration="" or="" a="" similar="" removal="" technology.="" however,="" it="" should="" be="" noted="" that="" fe/mn="" levels="" this="" high="" may="" cause="" very="" noticeable="" nuisance="" problems,="" including="" ``red="" water'',="" noticeable="" turbidity,="" laundry="" and="" sink="" staining,="" and="" interference="" with="" the="" brewing="" of="" tea="" and="" coffee.="" it="" is="" likely="" that="" many="" systems="" with="" source="" water="" fe/mn="" levels="" this="" high="" will="" have="" already="" addressed="" this="" problem.="" [[page="" 59277]]="" table="" viii.a.4.--="" co-occurrence="" of="" radon="" with="" dissolved="" iron="" in="" raw="" ground="">, \2\ (4188 Samples)
----------------------------------------------------------------------------------------------------------------
Dissolved Fe (mg/L) (percent)
Radon (pCi/L) -----------------------------------------------------------------------------
ND <0.3 0.3-1.5="" 1.5-2.5="">2.5 Totals
----------------------------------------------------------------------------------------------------------------
ND................................ 0.67 0.36 0.21 0.02 0.31 1.57
<100.............................. 2.17="" 1.72="" 0.53="" 0.12="" 0.48="" 5.02="" 100-300...........................="" 7.55="" 10.20="" 2.67="" 1.34="" 1.74="" 23.50="" 300-1,000.........................="" 18.89="" 22.61="" \3\="" 3.08="" 0.57="" 1.31="" 46.46="" 1,000-3,000.......................="" 6.42="" 9.05="" 0.74="" 0.10="" 0.62="" 16.93="">3,000............................ 2.10 3.82 0.31 0.02 0.26 6.51
-----------------------------------------------------------------------------
Totals........................ 37.80 47.76 7.54 2.17 4.72 100.00
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Based on analyses as described in USEPA 1999c.
\2\ The USGS National Water Information System (NWIS) database was used for this analysis.
\3\ Shaded area denotes region where radon level is above MCL and dissolved iron is above 0.3 mg/L, the
secondary MCL for iron.
Table VIII.A.5.--Co-Occurrence of Radon With Dissolved Manganese in Raw Ground Water 1, 2 (4189 Samples)
----------------------------------------------------------------------------------------------------------------
Dissolved Mn (mg/L) (percent)
Radon (pCi/L) ----------------------------------------------------------------
ND <0.02 0.02-0.05="">.050 Totals
----------------------------------------------------------------------------------------------------------------
ND............................................. 0.69 0.26 0.05 0.57 1.57
<100........................................... 2.67="" 0.84="" 0.36="" 1.15="" 5.02="" 100-300........................................="" 8.00="" 5.97="" 2.20="" 7.33="" 23.50="" 300-1,000......................................="" 21.99="" 11.84="" 3.17="" \3\="" 9.48="" 46.48="" 1,000-3,000....................................="" 6.45="" 5.90="" 1.24="" 3.34="" 16.93="">3,000......................................... 1.43 3.39 0.53 1.17 6.52
----------------------------------------------------------------
Totals..................................... 41.23 28.20 7.55 23.04 100.00
----------------------------------------------------------------------------------------------------------------
Notes: \1\ and \2\: See Table VIII.A.4.
\3\ Shaded area denotes region where radon level is above MCL and dissolved manganese is above 0.05 mg/L, the
secondary MCL for manganese.
A similar analysis of the National Inorganic and Radionuclides
Survey (NIRS) database, which sampled finished ground water, suggests
that greater than 81 percent of GW systems sampled have dissolved Fe/Mn
levels less than 0.3 mg/L and greater than 97 percent of systems
sampled have levels less than 1.5 mg/L (USEPA 1999h). Table VIII.A.6
compares combined Fe/Mn levels predicted by the NIRS database to occur
in finished ground water with levels predicted by NWIS to occur in raw
ground water. This table is consistent with expectations that the vast
majority of ground water systems will have combined Fe/Mn levels below
1-2 mg/L and that a significant fraction of ground water systems with
Fe/Mn levels above the SMCL are already taking measures to reduce Fe/Mn
levels.
Table VIII.A.6.--Co-Occurrence of Radon With Dissolved Combined Iron and Manganese in Raw and Finished Ground
Water
----------------------------------------------------------------------------------------------------------------
Percent of samples with dissolved
combined Fe and Mn (mg/L) (percent)
Ground water type --------------------------------------- Data sources
<0.3><1.5 ----------------------------------------------------------------------------------------------------------------="" finished="" ground="" water............="">81, >93 >97 >99 NIRS,\1\ AWWA Water:/Stats \2\
Raw Ground Water................. >85, >71 >95 >88 NWIS,\3\ AWWA Water:/Stats
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ ``National Inorganics and Radionuclides Survey'': See USEPA 1999c for references.
\2\ American Water Works Association, ``Water:/Stats, 1996 Survey: Water Quality''.
\3\ USGS, National Water Information System.
An analysis of the American Water Works Association (AWWA)
``Water:/ Stats'' database corroborates these conclusions: average Fe/
Mn levels in finished water from 442 ground water systems showed that
greater than 93 percent of the systems had combined Fe/Mn levels less
than 0.3 mg/L and greater than 99 percent of systems had combined Fe/Mn
levels less than 1.5 mg/L (AWWA 1997); average Fe/Mn levels in raw
ground water from 433 systems showed that greater than 71 percent of
systems had combined Fe/Mn levels less than 0.3 mg/L and greater than
88 percent of systems had Fe/Mn levels less than 1.5 mg/L. While this
analysis does support the conclusions from NIRS and NWIS, it should be
noted that the AWWA ``Water:/Stats Survey'' is skewed towards large
ground water systems: only 3.4 percent of the systems surveyed serve
fewer than 10,000 persons, whereas at the national
[[Page 59278]]
level, greater than 95 percent of ground water systems serve fewer than
10,000 persons. In comparison, NIRS was designed to be nationally
representative of contaminant occurrence in CWSs, while NWIS is a
``data bank'' in which the U.S. Geological Survey stores water
contaminant data from its various studies. While the data in NWIS was
not collected as part of a designed national survey (and hence can not
be claimed to be necessarily nationally representative), it is arguably
nationally representative based on its large sample size and its wide
distribution of sample collection locations (USEPA 1999c).
(g) Disinfection Assumptions. It was assumed that all systems
adding treatment would include disinfection. Since a significant
fraction of ground water systems already disinfect, the percentage of
systems that would have to add disinfection was estimated from a
``disinfection-in-place baseline'', as described in the Radon Health
Risk Reduction and Cost Analysis published on February 26, 1999 (64 FR
9559). It should be noted that this baseline is nationally
representative. Some States will, of course, have higher proportions of
ground water systems with disinfection-in-place (e.g., those States
that require that ground water systems disinfect) and some will have
lower proportions. Since the cost estimates being calculated are at the
national level, EPA believes that this assumption is valid since this
will over-estimate costs for systems in some States and under-estimate
costs for systems in other States, with the respective cost errors
tending to cancel at the national level. As a simplifying cost
assumption, chlorination was assumed for all systems adding
disinfection. The actual choice of disinfection technology should, of
course, be made on a case by case basis. The fact that many systems
will choose disinfection systems other than chlorination and that some
systems will not add disinfection at all is captured in the uncertainty
analysis, described later in this section.
(h) Comparison of Modeled Costs with Real Costs from Case Studies.
Figure VIII.A.1 compares modeled total capital costs against case
studies of actual aeration treatment installations for radon and VOCs
found in the literature and gathered by EPA. It should be noted that
these case studies include all pre- and post-treatments capital costs
and costs for land, housing structures, permits, and all other capital
added with the aeration process. If EPA's assumptions regarding pre-
and post-treatments were seriously flawed, this comparison would
demonstrate the fact. As can be seen, EPA's models fit the data fairly
well and, in fact, Figure VIII.A.2 shows that the ``typical cost
model'' rather closely approximates a power fit through the capital
cost data for the larger systems and significantly over-estimates
capital costs for small systems.
The ``PTA Cost Model'' represents EPA's best estimate of the costs
of constructing and operating a PTA system under the associated design
assumptions (steel shell, below-ground concrete clearwell, structure,
etc.). This design was intended to be fairly typical of those systems
serving more than 500 persons and up to 1,000,000 persons. The ``High
Side PTA Cost Model'' represents EPA's best estimate of the costs of
constructing and operating a PTA system under the same basic treatment
design, but including significantly higher land, structure, and
permitting costs. This model was intended to be fairly typical of
systems that are ``land-locked'' in suburban or urban areas where land
costs, building codes, and permitting demands may be much higher than
for typical situations. The ``Low Side PTA Cost Model'' represents
EPA's best estimate of the costs of constructing and operating a PTA
system using designs more typical of very small systems, including
package plant installations. This model is described in the Radon
Technologies and Costs Document (USEPA 1999h). As can be seen in Figure
VIII.A.1, the PTA Cost and High Side PTA Cost models are representative
of the systems with design flows greater than 0.1 MGD. All of these
models tend to over-estimate costs for those systems with smaller
design flows.
The relative percentages of non-compliant systems modeled by the
low-, typical-, and high-side costs are shown in the ``decision tree''
in Table 7-3 of the Regulatory Impact Assessment supporting this
proposal. As part of the uncertainty analysis (described later in this
section), these decision tree percentages were varied significantly.
The results and assumptions are presented in detail in Section 10.8.3
of the Regulatory Impact Assessment. Based on a sensitivity analysis of
the relative impacts of all the cost elements studied, the variance in
the decision tree percentage values had much less of an impact on
national costs compared to the variance in the treatment unit costs ($/
kgal).
BILLING CODE 6560-50-P
[[Page 59279]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.003
[[Page 59280]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.004
BILLING CODE 6560-50-C
[[Page 59281]]
Figure VIII.A.2 compares the EPA aeration capital cost models
against best fits to aeration capital cost case studies from the Radon
Technologies and Costs Document (which includes aeration installations
for VOCs) and to capital costs for radon case studies as reported by
American Water Works Association Research Foundation (AWWARF 1998b). In
general, EPA's unit cost estimates are supported by the case studies
cited previously and by the findings reported by the AWWARF (AWWARF
1998b).
Figure VIII.A.3 shows that EPA's modeled operations and maintenance
(O&M) costs are representative of the case study cost data. It should
be noted that EPA is modeling incremental O&M aeration costs
(additional O&M costs due to the addition of radon treatment) and that
many of the radon case studies and all of the VOCs case studies report
total O&M costs, which include O&M costs not related to the removal of
radon. For this reason, the case study O&M costs would be expected to
be considerably higher than the modeled costs, especially for the
larger systems (which tend to have other processes in place that
require substantial O&M costs). For example, most of the case studies
using disinfection already had disinfection in place before adding
aeration for radon. Since it is very difficult to separate the
individual components of O&M costs without detailed site-specific
information, these disinfection O&M costs are included in the O&M costs
shown even though they are not related to treatment added for radon. As
described previously, EPA did model O&M costs for disinfection and
sequestration for iron and manganese and did include these in its
national cost estimates. Figure VIII.A.3 compares modeled O&M costs for
aeration with and without disinfection. Modeled O&M costs for iron/
manganese stabilization and corrosion control are included through a
weighting procedure that simulates 25 percent of small systems and 15
percent of large systems adding a chemical inhibitor. EPA solicits
public comment and data on treatment costs and performance for the
removal of radon from drinking water.
BILLING CODE 6560-50-P
[[Page 59282]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.005
BILLING CODE 6560-50-C
[[Page 59283]]
Figures VIII.A.4 and VIII.A.5 compare the modeled capital costs and
O&M costs for GAC against actual costs reported in case studies (USEPA
1999a, AWWARF 1998b). As can be readily seen, EPA's modeled costs are
significantly higher than the actual costs, especially so for very
small flows. To account for this discrepancy, EPA used the best fit
through the case study data to generate a calibrated GAC model for
capital and O&M costs. EPA calculated GAC treatment costs based on this
model and did an uncertainty analysis on GAC costs assuming that while
the modeled costs were typical, they could be as high as the GAC-COST
predictions. This procedure is described in more detail in the radon
HRRCA.
EPA also estimated point-of-entry GAC (POE-GAC) costs for very
small systems. While capital and standard maintenance costs may be
affordable ($100-$350 per household per year), monitoring costs can
make POE-GAC much more expensive. EPA estimates (USEPA 1998g) that
monitoring costs alone can be as much as $140 per household per year. A
``high end'' estimate for POE-GAC is $1,000 per household per year. If
more cost-effective monitoring and maintenance program schemes are
devised, these costs may be considerably lower.
In general, treatment costs may vary significantly depending on
local circumstances. For example, costs of treatment will be less than
shown if contaminant concentration levels encountered in the raw water
are lower than those used for the calculations or if an existing
clearwell can be retrofitted for aeration. However, costs of treatment
will be higher if oxidation/filtration pre-treatment is required for
iron and manganese removal or if water must be piped from the well-head
to an off-site area for treatment.
BILLING CODE 6560-50-P
[[Page 59284]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.006
[[Page 59285]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.007
BILLING CODE 6560-50-C
[[Page 59286]]
(i) Uncertainty Analysis for Treatment Costs. To estimate the
uncertainty in national treatment costs, EPA estimated credible ranges
and distributions of values for the most important factors (inputs)
affecting costs. Distributions of selected inputs were then used in a
Monte Carlo analysis to explore the uncertainty in national costs. The
cost factors that were analyzed include:
Numbers of systems in the various size categories;
The distribution of the numbers of sources (wells) per
system in each size category;
Distributions of populations served in each size category;
Annual household water consumption;
Proportions of systems and wells exceeding radon limits;
and
Unit costs of radon treatment technologies (aeration and
GAC).
Each of these inputs was modeled using probability distributions
that reflect the spread in the available data. In some cases,
(distributions of populations served, daily household water
consumption, unit costs) variability was estimable from SDWIS, the
CWSS, or other sources. In the case of the numbers of systems of
different sizes, the estimated variability was greatest for the
smallest systems, less for the moderate size systems, and the numbers
of the largest systems (serving greater than 100,000 customers) was
assumed to be known with certainty. The variation in the proportions of
systems and sources above radon limits was estimated based on EPA's
recent analysis (USEPA 1999l) of inter- and intra-system radon
variability in radon levels.
In addition to these inputs, the estimated percentages of systems
choosing particular treatment technologies (the ``decision tree'') were
allowed to vary as well. Three decision tree matrices were used,
corresponding to a central tendency estimate of the proportions of
systems choosing specific mitigation technologies, and to lower- and
higher-cost distributions of technology selection. When the simulation
was run, the central tendency matrix was selected in 80 percent of the
iterations, and the low- and high-cost decision matrices were selected
in ten percent of the iterations each.
The variability in the estimated mitigation costs was examined
using a conservative test case in which all systems above an MCL of 300
pCi/L were assumed to mitigate to comply with the MCL. The results of
the analysis are described in detail in the radon Health Risk Reduction
and Cost Analysis. In general, the distribution of cost estimates, even
with all the variables included in the Monte Carlo analysis, is much
narrower than the corresponding distribution of risk and benefit
results. For this hypothetical scenario, the fifth percentile cost
estimate is $455 million per year, while the 95th percentile estimate
is $599 million per year (only 32 percent higher). The compactness in
spread in national costs relative to the spread in national benefits is
primarily due to the fact that the variability in the individual cost
model inputs is low relative to the variability in some of the inputs
(e.g., individual risk) to the benefits model.
(j) Potential Interactions Between the Radon Rule and Upcoming and
Existing Rules Affecting Ground Water Systems: Aeration and GAC are BAT
for more than 25 and 50 currently regulated contaminants, respectively.
Both technologies have been well-demonstrated and the secondary effects
of each technology are well understood (See, e.g., Cornwell 1990,
Umphres and Van Wagner 1986, AWWA 1990). These technologies are also
used to remove other contaminants from drinking water, including taste
and odor causing compounds. The Community Water System Survey (USEPA
1997a) indicates that 2 to 5 percent of ground water systems serving
fewer than 500 persons currently have aeration treatment in place. Of
systems serving more than 500 persons, 10-25 percent of these systems
have aeration treatment at one or more entry points.
In the case of aeration, these secondary effects include carbon
dioxide release (pH increase), oxygen uptake, and potential bacterial
density increases, all of which potentially impact other existing and
future drinking water regulations that pertain to ground water. In the
case of GAC treatment, potential bacterial density increases are of
concern. These potential interactions are described in a following
section. (Concerns that are specific to radon removal and secondary
effects due to other contaminants, e.g., radium and uranium, are
discussed in part 3 of this Section.)
(k) Ground Water Rule: Since the treatment techniques applicable to
the removal of radon, i.e., aeration, GAC, and/or ventilated storage,
may result in increases in microbial activity (NAS 1999b, Spencer et
al. 1999), it is important that water systems determine whether post-
treatment disinfection is necessary. The ``Ten States Standards''
(GLUMRB 1997) suggest that disinfection should follow ground water
exposure to the atmosphere (e.g., aeration or atmospheric storage). The
Ten State Standards also suggest that systems using GAC treatment
implement ``provisions for a free chlorine residual and adequate
contact time in the water following the [GAC] filters and prior to
distribution.'' While EPA is not requiring that disinfection be used in
conjunction with any treatment for radon, it is including costs for
disinfection with treatment in accordance with good engineering
practice. Cost assumptions for disinfection, including clearwell sizing
for 5-10 minutes of contact time, are consistent with 4-log viral
inactivation for ground water, which is expected to be consistent with
requirements in the upcoming Ground Water Rule.
It should be noted that air is not a significant pathogen vector
and thus aeration does not necessarily increase pathogenic risk for
ground water users. However, bacterial activity can increase upon
aeration and/or treatment with GAC. In the case of aeration treatment,
bacteria that oxidize iron and/or sulfide may proliferate because of
the oxygen increase; in the case of GAC treatment, bacteria may
proliferate since the GAC surface tends to accumulate organic matter
and nutrients that support the bacteria. In either case, heterotrophic
plate count limits may become high enough to be of concern and for this
reason disinfection may be necessary (USEPA 1999h, NAS 1999b).
(l) Disinfectants and Disinfection Byproducts (D/DBP) Rule:
Commonly used disinfection practices for ground water systems include
chlorination and, especially for small systems with limited
distribution systems, ultraviolet (UV) radiation. Disinfection is used
by many ground water systems because it decreases microbial risks from
microbial contamination of ground water (NAS 1999b). However, there is
a trade-off between a reduction in microbial risks and the risks
introduced from disinfection by-products. Various disinfectant by-
products (DBPs) can be formed depending on the disinfectant used, the
disinfectant concentration and contact time, water temperature, the
levels of DBP pre-cursors like natural organic materials and bromide,
etc. For example, chlorination by-products like trihalomethanes can
result from the interaction between chlorine chemical species and
naturally occurring organic materials (NOM) and bromate can result from
the ozonation of waters with sufficiently high levels of naturally
occurring bromide ion.
Ground water systems tend to have significantly lower
trihalomethane (THM) organic precursors than surface waters, although
this is not always the case. Total organic carbon (TOC) is often
[[Page 59287]]
used as a surrogate for formation of one important class of DBPs, total
trihalomethanes (THM), since the THM formation potential of chlorinated
waters correlates with TOC. As reported in the proposed Disinfectants
and Disinfection Byproducts Rule (July 29, 1994: 59 FR 38668), a survey
of surface waters showed TOC levels at the 25th, 50th, and 75th
percentiles of 2.6, 4.0, and 6.0 mg/L, respectively; ground waters
showed TOC levels at the same percentiles of ``non-detect'', 0.8, and
1.9 mg/L, respectively. Nationally, typical ground waters have low TOC
levels. However, some areas of the U.S., e.g., the Southeastern U.S.
(EPA Region 4), have some aquifers with high TOC levels.
One approach for the minimization of DBP formation in drinking
water is to employ a disinfectant other than chlorine. Primary
disinfection with chloramination, ozonation, or UV radiation are
examples. However, other considerations may apply. For example,
ozonation of ground water with sufficiently high bromide levels may
result in significant levels of the DBP bromate. If a residual is
required, it may be necessary to add secondary chlorination to maintain
a residual in the distribution system. Other strategies include
reducing the precursor concentration prior to chlorination, removal of
THMs after their formation, and the installation of a second
chlorination point in the distribution system. This last approach
allows much lower chlorination levels to be used for primary
chlorination, which greatly reduces THM formation.
While these strategies may be employed to minimize the formation of
DBPs and, thereby reducing potential DBP risks and avoiding MCL
violations for the DBP rule, there are other reasons to expect minimal
interactions between the radon rule and the D/DBP rule. Namely, EPA
expects that the radon rule will not result in a large percentage of
systems adding disinfection because of the need to treat for radon.
Since the primary regulatory option for small ground water systems is
the MCL/MMM option (MCL = 4000 pCi/L) and less than one percent (1%) of
small systems have radon levels that high, EPA does not expect many
small systems to add treatment for radon in response to the radon rule,
resulting in a very small percentage of small systems adding
disinfection. Roughly half of all small systems already half
disinfection in place already, further suggesting minimal small system
impact from the radon rule. While EPA also expects that many large
systems will also adopt the MCL/MMM option, EPA estimates that 95-97
percent of large ground water systems are already disinfecting, and
thus would not have to add disinfection if treating for radon. For the
expected small minority of systems that do add chlorination
disinfection with radon treatment, the trade-off between a reduction in
risks from radon exposure to an increase in risk from disinfection by-
products will need to be carefully considered by the system installing
treatment and strategies to minimize DBP formation should be
implemented (NRC 1997, NAS 1999b, Spencer et al. 1999).
(m) Lead and Copper Rule: For several reasons, it is expected that
few systems already in compliance with the Lead and Copper Rule will
experience direct cost impacts because of the Radon Rule. Systems
serving fewer than 50,000 persons do not have to modify corrosion
control practices if the lead and/or copper contaminant trigger levels
are not exceeded. For the reasons explained next, aeration is not
expected to result in increased lead and copper levels in the vast
majority of cases. While larger systems will have to include radon
treatment into their over-all ``optimal corrosion control'' plans as
they are updated, aeration tends to reduce or maintain corrosivity
levels and should not result in measures beyond those included in the
national costs for the proposed radon rule.
Aeration of ground water for radon treatment tends to raise the pH
of water (Kinner et al. 1990, as cited by NAS 1999b, Spencer et al.
1999), since it tends to remove dissolved carbon dioxide, which forms
carbonic acid when dissolved in water. In a study of VOCs removal by
aeration, the American Water Works Association (AWWA 1990) reported
that the net effect of aeration was ``no increase in corrosivity'': The
reduction in carbon dioxide levels resulted in higher pH and in
increased stability of carbonate minerals that serve to protect
distribution systems, negating the corrosive effects of increased
oxygen levels. The NAS concludes (NAS 1999b and references cited within
Spencer et al. 1999) that studies suggest that corrosivity tends to
decrease with aeration, but that a minority of systems that aerate may
have to add a corrosion inhibitor to stabilize the impacts of the
increased oxygen levels. As described previously, EPA has assumed in
its national costs that, of the systems that install aeration, 25
percent of small systems and 15 percent of large systems will add
chemical inhibitors for the dual purposes of corrosion control and the
control of iron and manganese.
(n) Arsenic Rule: It is expected that there will be no significant
negative relationships between compliance measures for the Arsenic and
Radon Rules. In fact, one of the few expected impacts is beneficial:
aeration plus disinfection may serve to pre-oxidize As(III) to the more
readily removable As(V) form. However, the benefits estimated in this
notice do not reflect this potential benefit.
3. Descriptions of Technologies and Issues
(a) Aeration. Aeration techniques for removal of radon from
drinking water include active processes such as diffused bubble
aeration (DBA), packed tower aeration (PTA), simple spray aeration,
slat tray aeration, and free fall aeration, with or without spray
aerators. Passive aeration processes such as free-standing, open air
storage of water for reduction of radon may be effective for systems
requiring lower removal efficiencies. Additional removal of radon via
radioactive decay (into the daughter products of radon) may also occur
in storage tanks and in pipelines which distribute drinking water,
reducing radon by approximately 10 to 30 percent, within 8 to 30 hour
detention periods. Although all of these aeration processes may be
effective, depending on site specific conditions, only active aeration
processes are considered BAT. Site specific considerations that may
influence an individual water system's choice of treatment include
source water quality (including concentrations of radon and other
contaminants removed or otherwise affected by aeration), institutional
or labor constraints, wellhead location, seasonal climate (e.g.,
temperature), site-specific design factors, and local preferences.
Identical treatment designs may achieve different radon removal
efficiencies at individual water systems, depending upon these factors.
A design for a technology may be altered to increase the radon removal
efficiency, e.g., an increase in the technology's air:water ratio (the
respective flows of air and water being mixed) may increase the radon
removal efficiency to account for local conditions that depress the
radon removal efficiency. In some cases, the removal efficiency
requirement may be high enough that only high performance aeration
technologies (e.g., packed tower aeration) will achieve the desired
removals.
High performance aeration technologies, e.g., packed tower aeration
(PTA) and package plant aerators with high air:water ratios like
shallow tray aeration (STA) or multi-stage bubble
[[Page 59288]]
aeration (MSBA), provide the most efficient transfer of radon from
water to air, with the ability to remove greater than 99 percent of
radon from water. A supply which requires a smaller reduction of radon,
e.g., 50 percent, could opt to install one of these technologies and
treat 50 percent of its source water and subsequently blend the treated
with raw water, or it may design a shorter packed tower to achieve
compliance with the MCL, both of which are significantly cheaper than
treating the entire flow to 99 percent radon removal. Other advantages
of high performance aeration include: removal of hydrogen sulfide,
carbon dioxide, and VOCs, and oxidation of iron and manganese. Full-
scale PTA, STA, and MSBA installations have been constructed for the
removal of radon for very small up to medium sized-systems (AWWARF
1998b, USEPA 1999a). In addition to these case studies, full-scale
aeration facilities for VOCs removal for medium to large-sized systems
have been reported in the literature (AWWA 1990). Since radon is more
easily air stripped than most volatile organic compounds, and high
performance aeration technologies have been shown to be efficient forms
of aeration for VOC removal (Kavanaugh and Trussell 1989, Dyksen et al.
1995), these technologies are appropriate as BAT for radon.
Treatment issues regarding aeration have been discussed in the
literature (e.g., Dihm and Carr 1988, Kinner et al. 1990b, Dell'Orco et
al. 1998, AWWARF 1998b) and by EPA (USEPA 1999d). These issues include
the potential for bacteria fouling (e.g., iron/manganese/sulfide
oxidizing bacteria), iron and manganese chemical precipitation and
scaling, and corrosivity changes. Bacteria fouling and Fe/Mn scaling
may clog or otherwise impede operations at an aeration facility,
requiring preventative maintenance and/or periodic cleaning. Regarding
corrosivity, the aeration process tends to reduce carbon dioxide levels
(and raise pH, which tends to decrease corrosivity) and introduce
oxygen (which tends to increase corrosivity). Whether or not
corrosivity increases or decreases depends on site specific factors. In
general, the degree to which these treatment issues may occur depends
on the source water quality, ambient water and air temperatures, pre-
and post-treatments added or in place, the type of aeration used, and
other factors. To account for the cost impacts of dealing with Fe/Mn/
carbonate scaling, EPA has included the capital and operation and
maintenance costs of pre-treatment with a scalant stabilizer (which
also may serve as a corrosion inhibitor, depending upon the type of
corrosivity). Pre-/Post-treatment with a disinfectant to control
biological fouling and to provide four-log viral deactivation (assuming
a five minute contact time at 1.0-1.5 mg/L chlorine) has also been
assumed in cost estimates. EPA assumed that those groundwater systems
without disinfection already in place will add disinfection when
aerating.
The PTA process involves the use of packing materials to create
pore spaces that greatly increase the air:water contact time for a
given flow of air into water. In counter-current PTA, the water is
pumped to the top of the tower, then distributed through the tower with
spray nozzles or distribution trays. The water flows downward against a
current of air, which is blown from the bottom of the tower by forced
or induced draft. The air space at the top of the tower is continually
refreshed with ventilators. This design results in continuous and
thorough contact of the water with ambient air. The factors that
determine the radon removal efficiency are the air:water ratio (the
ratio of air blown into the bottom of the tower and the water pumped
into the top of the tower), the type and number of packing material,
the internal tower dimensions, the water loading rate, the radon level
in the influent and in the ambient air, and the water and air
temperatures. A typical packed tower aeration installation consists of:
(1) the tower: a metal (stainless steel or aluminum), fiber-glass
reinforced plastic, or concrete tower with internals consisting of
packing material with supports and distributors, (2) a blower or
blowers, (3) effluent storage, which is generally provided as a
concrete clearwell (airwell) below the tower; very small systems may
use metal or plastic storage tanks, and (4) effluent pumping. Pumping
into the tower is performed either through modification or replacement
of the original well pump.
Commercially available high performance package plant aerators
(USEPA 1999a, AWWARF 1998b) include multi-stage bubble aerators (MSBA),
shallow tray aerators (STA), and other high air:water ratio designs.
MSBA units typically consist of shallow (typically less than 1.5 feet
deep) high-density polyethylene tanks partitioned into multiple stages
with stainless steel or plastic dividers. Each stage is provided with
an aerator, each of which is connected to the air supply manifold. STA
units typically consist of one to six stacked tray modules (each 18 to
30 inches deep). Water is pumped through each tray as air is blown
through diffusers at the bottom of the tray, creating turbulent mixing
of the air and water. These package plant aerators have several
distinct advantages: they are low-profile and compact (small
footprint), are considered straightforward to install, and are
relatively easy to maintain.
Other varieties of active aeration include diffused bubble
aeration, which involves the bubbling of air into the water basin (of
varying depth and design) via a set of air bubble diffusors. Forms vary
from designs with shallow depth tanks containing thousands of diffusers
to ``low technology'' designs involving bubbling air into a storage
tank via a perforated hose connected to a blower. Some forms of
diffused bubble aeration can remove up to 99.9 percent of radon from
drinking water; simpler varieties can remove from 80 to > 90 percent of
radon. One of the main advantages of diffused bubble aeration is its
potential for making use of existing basins for the aeration process,
which substantially reduces construction costs. Even if the aeration
basin must be newly constructed, this process can be more cost
effective than PTA for small systems. The disadvantages of diffused
aeration include the requirement for increased contact time, the
impracticality of large air-to-water ratios because of air pressure
drops, and overall less efficient mass transfer of radon from water.
The level of contact between air and water achievable in a packed tower
aerator is difficult to obtain in a simple diffused air system (i.e.,
forms like MSBA can achieve comparable contacts).
The Radon Technology and Cost document (USEPA 1999h) summarizes
treatability studies for four diffused bubble aeration installations.
One of the case studies involves a full-scale diffused aeration plant
in Belstone, England, which provided a long-term radon removal
efficiency of 97 percent. This plant (design flow of 2.5 mgd) was
designed with an air:water ratio, using 2,800 air diffusers, each
designed to supply a maximum of 0.8 cubic feet per minute, and a 24-
minute retention time. In a field test of a diffused bubble aeration
system, Kinner et al. (1990) report that removals of 90 to 99 percent
were achieved at air-to-water ratios of 5 and 15, respectively.
Spray aerators direct water upward, vertically, or at an angle,
dispersing the water into small droplets, which provide a large
air:water interfacial area for radon volatilization. In single pass
mode, depending upon the air:water ratio, removal efficiencies of >50
to >85 percent can be achieved. In multiple pass mode, 99 percent
removals can be
[[Page 59289]]
achieved. Most of the advantages cited previously for diffused aeration
also apply to spray aeration. Disadvantages include the need for a
large operating area and operating problems during cold weather months
when the temperature is below the freezing point. Costs associated with
this option (for all sizes of water treatment plants) have not been
developed by EPA, but case studies (USEPA 1999a, AWWARF 1998b) indicate
that it is cost-competitive with other small systems aeration
technologies.
EPA has evaluated other, less technology-intensive (``low-
technology''), options which may be suitable for small water systems,
and which may cost less than the options described previously to
install and operate (Kinner et al. 1990b, USEPA 1999a, AWWARF 1998b).
These options include: atmospheric storage, free fall with nozzle-type
aerator, bubble aerators, blending, and slat tray aerators. Limited
data concerning these low-technology alternatives are reviewed in USEPA
1999a and AWWARF 1998b. Case studies show that atmospheric storage with
a detention time of nine hours resulted in removals of 7-13 percent and
a detention time of 30 hours in removals of around 35 percent. Dixon
and Lee (1987) report that blending 6.34 MG of well water with a radon
level of 1079 pCi/L with 18.34 MG of surface water resulted in effluent
water with 226 pCi/L. Other storage case studies (detention times
ranging from 8 to 23 hours) show that free-fall into a tank, free-fall
with simple bubble aeration, simple spray aeration with free-fall, and
simple bubble aeration remove 50-70 percent, 85-95 percent, 60-70
percent, and 80-95 percent of radon, respectively. More detail on an
example will illustrate the simplicity of the treatment involved: the
case study for ``free-fall with simple bubble aeration'' cited
previously involved the introduction of water through two feet of free
fall into a tank equipped with garden hose (punctured) bubble aerators,
where the air was supplied by a laboratory air pump. Kinner et al.
(1990b) concluded that very effective radon reduction can be achieved
by simple aeration technologies that may be easily applied in small
communities.
(i) Evaluation of Radon Off-Gas Emissions Risks. Since this notice
contains a proposal to reduce radon concentrations in drinking water by
setting an MCL, and the EPA is proposing aeration as BAT for meeting
the MCL, the Agency undertook an evaluation of risks associated with
potential air emissions of radon from water treatment facilities due to
aeration of drinking water. In the first evaluation (USEPA 1988a,
1993a), EPA used radon data from 20 drinking water systems in the U.S.
which, according to the Nationwide Radon Survey (1985), contained the
highest levels of radon in drinking water and affected the largest
populations and/or drinking water communities. EPA estimated the
potential annual emissions (in pCi radon/yr) from these facilities,
assuming 100 percent radon removal.
These radon emissions estimates were used as inputs to the AIRDOS-
EPA model, which is a dispersion model that can be used to estimate the
concentration of radon at a point some distance from the point source
(e.g., a packed tower vent). This model is the predecessor to the newer
CAP-88-PC model, which combined AIRDOS with the DARTAB model, which
estimates the total lifetime risk to individuals and the total health
impact for populations. The underlying physical models in CAP-88 are
essentially the same as those underlying AIRDOS and DARTAB (USEPA
1992c). In fact, the main differences between CAP-88-PC model and its
predecessors is that CAP-88-PC is intended for wide-spread use in a
personal computer environment (the CAP-88-PC model and its supporting
documentation can be downloaded from the EPA homepage, http://
www.epa.gov/rpdweb00/assessment/cap88.html). EPA has made comparisons
between the AIRDOS-EPA dispersion model results and actual annual-
average ground-level concentrations and found very good agreement. EPA
has studied the validity of AIRDOS-EPA and concluded that its
predictions are within a factor of two within actual average ground-
level concentrations, the results of which are as good as any existing
comparable model (USEPA 1992c).
Estimates of ground-level radon exposure were made for the
following parameters: air dispersion of radioactive emissions,
including radon and progeny isotopes of radon decay; concentrations in
the air and on the ground; amounts of radionuclides taken into the body
via inhalation of air and ingestion of meat, milk, and fresh
vegetables, dose rates to organs and estimates of fatal cancers to
exposed persons within a 50 kilometer radius of the water treatment
facilities. Estimates of individual risk and numbers of annual cancer
cases were completed for each of the 20 water systems, as well as a
crude estimate of U.S. risks (total national risks) based on a
projection of results obtained for the 20 water systems. These
estimates were based on exposure analyses on a limited number of model
plants, located in urban, suburban and rural settings, which were
scaled to evaluate a number of facilities. (A similar approach has been
used by the Agency in assessing risks associated with dispersion of
coal and oil combustion products.) The risk assessment results for the
20 systems indicate the following: a highest maximum lifetime risk of 2
x 10-\5\ for individuals within 50 km of one of
these systems, with a maximum incidence at the same location of 0.003
cancer cases per year; an estimate of annual cancer cases for all 20
systems of 0.0038 per year; and a crude U.S. estimate of 0.09 fatal
cancer cases/year due to air emissions if all drinking water supplies
are treated by aeration to meet an MCL of 300 pCi/L. Two other cases
were evaluated: (1) Assuming that small drinking water systems are
treated by aeration to meet the MCL/MMM option of 4000 pCi/L and large
systems are treated to meet the MCL of 300 pCi/L, the best estimate of
total national fatal cancer cases per year due to radon off-gas
emissions is 0.04 cases/year, and (2) Assuming that all systems treat
by aeration to meet the (A)MCL/MMM option of 4000 pCi/L , the best
estimate is 0.01 cases/year. These results of the risk assessment for
potential radon emissions from drinking water facilities are summarized
in Table VIII.A.7. For all MCL options shown, the maximum lifetime
individual risks from radon off-gas are much smaller (100 to 70,000
times smaller) than the average lifetime individual risks from the
untreated water. Regarding national population risks (fatal cancer
cases per year), the estimated population risk from radon off-gas is
850 to 17,000 times smaller than the estimated population risk from the
untreated water.
[[Page 59290]]
Table VIII.A.7.--Estimates of Risks at 20 Sites Due to Potential Radon Emissions From Aeration Units and Crude
Projection of Total U.S. Risk \1\
----------------------------------------------------------------------------------------------------------------
Concentration Emissions from Population risk \2\
Modeling scenario in water (pCi/ facility (Ci Maximum lifetime (fatal cancer cases
L) Rn/Yr) individual risk \2\ per year)
----------------------------------------------------------------------------------------------------------------
20 Facilities Modeled:
1............................. 1,839 2.79 3 x 10-7 7 x 10-5
2............................. 5,003 6.22 6 x 10-7 2 x 10-4
3............................. 2,175 2.85 3 x 10-7 9 x 10-5
4............................. 1,890 20.89 6 x 10-6 1 x 10-4
5............................. 1,310 1.81 5 x 10-7 9 x 10-7
6............................. 1,329 91.80 9 x 10-6 1 x 10-3
7............................. 4,085 2.26 2 x 10-7 3 x 10-5
8............................. 10,640 1.18 1 x 10-7 1 x 10-5
9............................. 3,083 0.55 5 x 10-8 7 x 10-6
10............................ 3,270 9.04 2 x 10-5 1 x 10-3
11............................ 2,565 3.54 7 x 10-6 6 x 10-4
12............................ 4,092 13.75 2 x 10-7 3 x 10-5
13............................ 16,135 2.23 2 x 10-7 3 x 10-5
14............................ 3,882 0.27 8 x 10-8 5 x 10-6
15............................ 1,244 1.03 3 x 10-7 2 x 10-5
16............................ 2,437 1.35 4 x 10-7 5 x 10-7
17............................ 996 8.94 9 x 10-7 2 x 10-4
18............................ 7,890 0.87 3 x 10-7 6 x 10-6
19............................ 9,195 1.02 3 x 10-7 1 x 10-5
20............................ 7,500 1.04 3 x 10-7 6 x 10-6
-----------------------------------------------------------------------------
Totals for All 20 Facilities...... 161 ..................... 0.004
----------------------------------------------------------------------------------------------------------------
Totals Assuming All U.S. Community 3700 ..................... 0.09
Water Systems Treat to 300 pCi/L
\3\, i.e., All Systems Meet MCL
of 300 pCi/L.
----------------------------------------------------------------------------------------------------------------
Totals Assuming All Small U.S. 1600 ..................... 0.04
Drinking Water Facilities Treat
to 4000 pCi/L \3\ and All Large
U.S. Drinking Water Treat to 300
pCi/L, i.e., All Small Systems
Meet MCL of 4000 pCi/L and All
Large Systems: meet MCL of 300
pCi/L.
----------------------------------------------------------------------------------------------------------------
Totals Assuming All U.S. Drinking 240 ..................... 0.01
Water Facilities Treat to 4000
pCi/L \3\, i.e., All Systems meet
MCL of 4000 pCi/L.
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Estimates of Risk Assessment Using AIRDOS-EPA to estimate radon exposure. The total U.S. risk is based on
the very conservative projection that all CWSs will treat to 200 pCi/L, USEPA 1993b.
\2\ Risks are based on the National Academy of Science's lifetime fatal cancer unit risk or radon in drinking
water of 6.7 x 10 -\7\.
\3\ USEPA 1999j.
A second ``worst case'' evaluation was performed using four
scenarios with high radon influent levels (ranging from 1,323 pCi/L to
110,000 pCi/L) and/or high flows to further determine whether
individuals living near water treatment plants would experience
significant increases in cancer risks due to radon off-gas emissions.
For this analysis, the MINEDOSE model was used in conjunction with
radon emissions estimates to estimate lifetime fatal cancer risks for
individuals living near the modeled facility. Emissions were estimated
using MINDOSE 1.0 (1989), a predecessor to COMPLY-R (1.2), which can be
downloaded from the EPA homepage (http://www.epa.gov/rpdweb00/
assessment/comply.html). Comply-R (1.2, radon-specific) is intended for
demonstrating compliance with the National Emissions Standards for
Hazardous Air Pollutants (NESHAPS) in 40 CFR 61, Subpart B, which are
the Federal standards for radon emissions from underground uranium
mines. While these standards do not apply to drinking water facilities,
the model can be used to estimate radon exposures from aeration vents
at drinking water facilities. To check for consistency between MINEDOSE
and COMPLY-R, several modeling scenarios done in the original analysis
with MINEDOSE were repeated using COMPLY-R and the results from
MINEDOSE were found to be conservative with respect to the COMPLY-R
results, i.e., COMPLY-R predicts lower exposures for the scenarios
modeled. The MINEDOSE code was originally used instead of the AIRDOS
code because of its relative ease of use. When modeling the same
scenarios with MINEDOSE and AIRDOS, the predicted exposures were
determined to be similar enough to warrant the use of MINEDOSE for this
work. The results from the MINEDOSE modeling work and subsequent work
(USEPA 1994a) concluded that even these ``worst case maximum individual
risks'' from radon off-gas were much smaller (300 to 1,000 times
smaller) than the average individual risks posed by the untreated
water.
(ii) Permitting of Radon Off-Gas from Drinking Water Facilities.
Radon emissions to ambient air are only Federally regulated under 40
CFR 61,
[[Page 59291]]
National Emission Standards for Hazardous Air Pollutants (NESHAPs).
These regulations apply to radon emissions under very specific
circumstances, including emissions of radon to ambient air from uranium
mine tailings, phosphogypsum stacks (40 CFR 61, Subpart R), Department
of Energy storage and disposal facilities for radium-containing
materials (40 CFR 61, Subpart Q), and underground uranium mines (40 CFR
61, Subpart B). At present, there are no State or Federal regulations
that directly apply to radon air emissions from water treatment
facilities.
To assess potential procedures (e.g., permit applications, off-gas
risk modeling) and costs that could be associated with radon off-gas
from aeration facilities, EPA gathered information from agencies
responsible for air permitting (USEPA 1999h), using California as a
case study. California air permitting requirements are expected to be
more restrictive than most States, and for this reason, it is
considered a conservative case study. The information gathered is not
expected to be nationally representative, but is illustrative as a
``worst case scenario''.
EPA contacted representatives from nine air districts in California
via telephone to determine the likely response of their district to
promulgation of a radon rule with an associated radon MCL requirement
(USEPA 1999h). The air boards were chosen to represent large,
metropolitan areas, medium-sized cities, and smaller, more rural areas.
The representatives responded to the following questions:
What is the likely response of your permitting board to
water systems installing aeration treatment to comply with the radon
rule?
What are the likely permitting procedures and costs for
water systems installing aeration for radon? Who would be responsible,
the permitting board or the water system, for carrying out each
procedure and paying the costs?
Will large water systems and small water systems follow
different procedures, or are procedures uniform regardless of water
system size (e.g., off-gas volume)? How do permitting costs change with
the applicant's system size?
Will water systems be required to perform off-gas risk
modeling as part of the permitting procedure or will they be required
to do other environmental impact analyses?
Would there be annual renewal procedures (e.g.,
reapplication, compliance monitoring) and costs? Who would be
responsible for carrying our the procedures and bearing the costs?
Is ongoing monitoring likely to be required?
Where possible, representatives provided estimates of time and cost
that could be incurred by water systems and the districts as a result
of the potential district response to the radon rule.
Responses to these questions indicated that the likely response to
a radon rule is similar across the California air districts contacted.
Most districts indicated they are likely to follow the lead of the
State. ``Following the State's lead'' means that, if the State includes
radon on its Toxic Air Contaminants List and establishes potency
factors (unit risk factors and expected exposure levels for radon), air
districts will probably regulate drinking water system aeration
facilities through permits. Permitting procedures are similar across
air districts and generally do not vary for facilities of different
sizes. However, permitting costs and who bears those costs can vary
significantly from air district to air district. Some portion of the
costs are likely to vary based on facility size or emissions level.
Currently, ``radionuclides'' (which includes radon) are on the
Toxic Air Contaminant Identification List developed by the California
Air Resources Board. Listed contaminants are categorized by priority,
and depending on what category a substance is in, the substance may or
may not have ``potency factors'' developed by California's Office of
Environmental Hazard Health Assessment (OEHHA). At the present time,
radon is ``Category 4A'', which means that OEHHA is not currently
planning on publishing values for the radon unit risk factor and
reference exposure level, indicating that air boards are not likely to
require permitting for radon off-gas at the present time. However,
radon has been proposed for elevation in priority to ``Category 3'',
which means that it could be a candidate for the development potency
numbers in the future. Since California air quality districts generally
follow the lead of OEHHA, if OEHHA publishes a unit risk factor and
reference exposure level for radon in the future, air districts are
then likely to evaluate whether radon should be considered in their air
permitting programs. If OEHHA decides not to establish potency factors
for radon, California air districts are not likely to require
permitting for radon off-gas from drinking water treatment plants.
Respondents indicated that typical permitting procedures were: a
system applies for a permit to construct; the board evaluates the
application and decides whether or not to issue a permit; a permit may
then be issued, after which the system may construct the aerator; the
District conducts an inspection and the system may or may not have to
perform testing; a public notice is issued if required by risk level
and proximity of schools; the District issues a permit to operate;
system must annually renew the permit (no monitoring or inspection
likely). It is likely that water systems in the more densely populated,
Metropolitan areas are more likely to need to do a risk assessment and
perform modeling as part of their permit application. Permitting costs
ranged from < $500="" for="" simple="" permitting="" up="" to="" $50,000="" for="" more="" complicated="" situations,="" with="" typical="" permitting="" costs="" reported="" in="" the="" $1,000="" to="" $5,000="" range.="" these="" costs="" do="" not="" include="" any="" radon="" dispersion="" controls="" or="" other="" engineering="" controls="" that="" might="" be="" required="" for="" the="" permit.="" (b)="" centralized="" liquid="" phase="" granular="" activated="" carbon="" (gac)="" and="" point-of-entry="" gac.="" gac="" removes="" radon="" from="" water="" via="" sorption.="" ``downflow''="" designs="" are="" used,="" in="" which="" the="" raw="" water="" is="" introduced="" at="" the="" top="" of="" the="" carbon="" bed="" and="" flows="" under="" pressure="" downwards="" through="" the="" bed.="" the="" treated="" water="" may="" then="" be="" disinfected="" or="" otherwise="" post-="" treated="" and="" piped="" to="" the="" distribution="" system.="" advantages="" to="" the="" use="" of="" gac="" relative="" to="" aeration="" include="" the="" lack="" of="" a="" need="" to="" break="" pressure="" (and="" hence="" re-pump),="" the="" lack="" of="" radon="" off-gas="" emissions,="" and,="" in="" very="" small="" systems="" applications="" with="" good="" water="" quality,="" gac="" typically="" has="" no="" moving="" parts="" and="" requires="" little="" maintenance.="" details="" regarding="" the="" process="" of="" radon="" removal="" via="" gac="" are="" provided="" elsewhere="" (usepa="" 1999h,="" awwarf="" 1998a,b).="" this="" discussion="" will="" focus="" on="" potential="" issues="" that="" small="" water="" systems="" may="" face="" if="" they="" choose="" gac="" for="" radon="" removal.="" of="" these,="" raw="" water="" quality="" is="" of="" paramount="" concern="" since="" it="" affects="" radon="" removal="" efficiency,="" unit="" lifetime,="" and="" the="" potential="" for="" secondary="" radiation="" hazards.="" radon,="" iron,="" uranium,="" and="" radium="" levels="" are="" most="" important.="" (i)="" radon="" influent="" levels="" for="" poe="" gac:="" gamma="" radiation="" hazards.="" an="" upper="" limit="" of="" 5,000="" pci/l="" of="" radon="" in="" influent="" water="" being="" treated="" by="" poe="" gac="" is="" suggested="" by="" rydell="" et="" al.="" (1989)="" and="" kinner="" et="" al.="" (1990b)="" to="" protect="" persons="" in="" frequent="" proximity="" to="" the="" carbon="" bed="" (i.e.,="" residents)="" from="" gamma="" ray="" exposures.="" this="" influent="" level="" is="" based="" on="" a="" residential="" exposure="" limit="" of="" 170="" mrem/year,="" or="" 0.058="" mr/hour="" based="" on="" 8="" hours/day="" of="" maximum="" exposure,="" 365="" days="" per="" year.="" the="" 170="" mrem/year="" limit="" was="" established="" by="" the="" national="" council="" on="" radiation="" [[page="" 59292]]="" protection="" bulletin="" (cited="" by="" rydell="" et="" al.="" 1989).="" note="" that="" this="" residential="" exposure="" limit="" is="" less="" conservative="" than="" the="" epa="" recommended="" limit="" of="" 100="" mrem/year="" for="" water="" treatment="" plant="" personnel.="" however,="" the="" assumption="" of="" 8="" hours/day="" of="" maximum="" proximity="" is="" extremely="" conservative.="" the="" 100="" mrem/year="" limit="" is="" achieved="" if="" a="" person="" gets="" maximum="" exposure="" for="" approximately="" 5="" hours="" per="" day="" or="" less,="" 365="" days="" per="" year,="" which="" is="" still="" a="" conservative="" assumption.="" rydell="" et="" al.="" determined="" this="" influent="" limit="" based="" on="" an="" empirical="" and="" theoretical="" relationship="" between="" radon="" influent="" level="" and="" gamma="" ray="" emissions="" from="" the="" carbon="" bed.="" as="" will="" be="" discussed="" next,="" based="" on="" recent="" work="" using="" improved="" gamma="" ray="" detection="" methodology,="" hess="" et="" al.="" (1998)="" report="" that="" this="" limit="" may="" be="" too="" low="" by="" a="" factor="" of="" 2,="" i.e.,="" the="" suggested="" radon="" influent="" limit="" may="" be="" closer="" to="" 10,000="" pci/l.="" note="" that="" these="" limits="" are="" based="" on="" assumptions="" about="" gac="" contact="" basin="" configurations,="" type="" and="" extent="" of="" shielding,="" length="" of="" time="" and="" proximity="" of="" persons="" to="" the="" unit,="" etc.="" while="" the="" ``rules-of-thumb''="" described="" previously="" are="" useful,="" appropriate="" radon="" influent="" limits="" may="" be="" higher="" or="" lower="" depending="" upon="" site-specific="" considerations="" and="" should="" be="" determined="" on="" a="" case-by-case="" basis.="" the="" university="" of="" maine="" reported="" results="" on="" the="" removal="" of="" radon="" from="" drinking="" water="" using="" gac="" (hess="" et="" al.="" 1998).="" nine="" carbon="" beds="" (all="" in="" maine),="" which="" had="" been="" in="" use="" for="" more="" than="" 10="" years="" by="" public="" water="" systems="" and="" private="" homes="" for="" radon="" removal,="" were="" studied.="" radon="" influent="" levels="" ranged="" from="" 330="" to="" 107,000="" pci/l,="" with="" a="" mean="" of="" 24,500="" pci/l="" and="" a="" standard="" deviation="" of="" 11,800="" pci/l.="" gamma="" ray="" emissions="" from="" the="" gac="" units="" and="" accumulated="" radon="" progeny,="" uranium,="" and="" radium="" were="" analyzed.="" gamma="" ray="" emissions="" from="" the="" gac="" surface="" ranged="" from="" 11.5="" ur/h="" to="" 301="" ur/h,="" with="" a="" mean="" of="" 78="" ur/h="" and="" a="" standard="" deviation="" of="" 82="" ur/h,="" and="" were="" 2="" to="" 4="" times="" lower="" than="" predicted="" by="" theory.="" the="" authors="" concluded="" that="" the="" limit="" of="" 5,000="" pci/l="" suggested="" by="" rydell="" et="" al.="" (1989)="" may="" be="" too="" low="" by="" a="" factor="" of="" 2="" or="" more.="" (ii)="" radon="" influent="" levels="" for="" centralized="" gac:="" gamma="" radiation="" hazards.="" using="" the="" very="" conservative="" assumption="" that="" a="" water="" treatment="" operator="" will="" be="" in="" close="" proximity="" for="" 40="" hours="" per="" week,="" the="" 100="" mrem/year="" translates="" to="" around="" 0.05="" mr/hour,="" which="" also="" corresponds="" to="" a="" maximum="" of="" 5,000-10,000="" pci/l="" of="" radon="" for="" small="" flows.="" however,="" since="" gac="" is="" likely="" to="" be="" used="" only="" by="" very="" small="" water="" systems="" and="" does="" not="" involve="" intensive="" o&m,="" much="" shorter="" work="" weeks="" are="" likely.="" using="" 10="" hours/week,="" the="" maximum="" radon="" influent="" level="" would="" be="" higher.="" again,="" these="" are="" ``rule-of-thumb''="" suggestions="" only.="" the="" best="" means="" to="" ensure="" that="" 100="" mrem/year="" maximum="" exposure="" limits="" are="" maintained="" is="" to="" implement="" appropriate="" monitoring="" of="" gamma="" levels="" in="" the="" treatment="" facility="" and="" to="" ensure="" that="" proper="" shielding="" and="" worker="" proximity="" restraints="" are="" engineered="" to="" minimize="" exposures.="" (iii)="" other="" water="" quality="" considerations:="" naturally-occurring="" iron="" and="" dissolved="" organic="" materials.="" the="" adsorption="" of="" iron="" precipitates="" can="" reduce="" a="" unit's="" radon="" removal="" efficiency,="" so="" that="" the="" raw="" water="" may="" need="" to="" be="" pre-treated="" to="" stabilize="" and/or="" remove="" the="" dissolved="" iron.="" the="" american="" water="" works="" association="" research="" foundation="" (awwarf="" 1998a,b)="" reports="" that="" waters="" with="" low="" iron="" and="" low="" levels="" of="" naturally="" occurring="" organic="" matter="" (``total="" organic="" carbon'',="" toc)="" can="" achieve="" good="" radon="" steady-state="" removals="" (i.e.,="" radon="" sorption="" equals="" radon="" decay),="" but="" that="" the="" negative="" effects="" of="" iron="" and="" toc="" on="" removal="" efficiencies="" may="" necessitate="" pilot="" testing="" to="" ensure="" proper="" contactor="" design.="" for="" raw="" water="" with="" high="" iron="" and/or="" toc,="" pre-filtration="" or="" pre-="" oxidation/filtration="" may="" be="" required="" to="" achieve="" good="" steady-state="" removals.="" (iv)="" other="" water="" quality="" considerations:="" naturally-occurring="" uranium="" and="" radium:="" uranium="" and="" radium="" raw="" water="" levels="" are="" also="" of="" concern="" since="" sorption="" may="" occur="" onto="" the="" gac="" surface,="" which="" results="" in="" uranium="" and="" radium="" occurrence="" in="" the="" gac="" filter="" backwash="" residuals="" and="" ultimately="" may="" create="" a="" final="" gac="" bed="" disposal="" problem.="" water="" quality="" (ph,="" iron="" levels,="" natural="" organic="" matter="" levels,="" alkalinity,="" etc.)="" determine="" the="" extent="" to="" which="" uranium="" and="" radium="" sorb="" to="" the="" gac="" surface.="" awwarf="" (1998b)="" reported="" results="" from="" case="" studies="" conducted="" over="" a="" two="" year="" period="" in="" new="" hampshire,="" new="" jersey,="" and="" colorado,="" including="" findings="" regarding="" loadings="" of="" uranium="" and="" radium="" on="" the="" gac="" surface="" and="" respective="" levels="" in="" backwash="" residuals.="" radon="" influent="" levels="" were="" 15,000-17,000="" pci/l,="" 2,220="" pci/l,="" and=""><7,500 pci/l="" at="" the="" new="" hampshire,="" new="" jersey,="" and="" colorado="" sites,="" respectively.="" in="" the="" new="" hampshire="" pilot="" study,="" backwash="" residuals="" contained="">200
pCi/g uranium and 50 to 60 pCi/g radium. For water
treatment residuals with uranium levels between 75 and 750 pCi/g, EPA
suggests that disposal measures be determined on a case-by-case basis
(USEPA 1994b). In general, disposal in a controlled landfill
environment may be necessary. The GAC bed itself accumulated less than
the limit of 75 pCi/g for all but one of the five GAC columns in New
Hampshire. For the New Jersey and Colorado pilot plants, uranium,
radium, and radon progeny levels were low enough in the backwash
residuals and the GAC bed that special disposal considerations were not
an issue. It should be noted that State disposal restrictions may be
more stringent than EPA's suggestions, which may make GAC a less
attractive alternative in these States.
(v) GAC Disposal Issues. Radon progeny (e.g., Pb-210, a beta
emitter) accumulation is also related to radon influent level. If radon
influent levels are high, the GAC unit lifetime may decrease
significantly, where this lifetime is defined as the length of time
between start-up and when an unacceptable accumulation of radioactive
Pb-210 occurs. While no Federal agency currently has the legislative
authority to regulate the disposal of wastes generated by water
treatment facilities on the basis of naturally occurring radioactive
materials (NORM), EPA (USEPA 1994b) suggests that NORM solid wastes
with radioactivity above 2,000 pCi/g be disposed of in appropriate low-
level radioactive waste facilities. Furthermore, given the prohibitive
expense and burden of disposing of low-level radioactive waste, EPA
would suggest that water treatment facilities avoid situations where
such high waste levels would expected to potentially occur. In the case
of wastes containing Pb-210, EPA suggests that case-by-case
determinations be made for determining appropriate disposal. In
summary, for higher radon influent levels, shorter bed lifetimes may be
appropriate to reduce Pb-210 build-up.
Hess et al. (1998), cited previously, also studied several methods
of cleaning the GAC bed by removing Pb-210 and radium from the spent
GAC with various chemical cleaning solutions (e.g., solutions of
hydrochloric acid, nitric acid, sodium hydroxide, etc.). Disposal of
the cleaned GAC and the much smaller volume of concentrated radon
progeny and radium is expected to be cheaper in some cases than
disposal of the contaminated GAC bed to a controlled disposal-facility.
The authors concluded that several of the cleaning solutions
(hydrochloric acid at 1 mole/liter, nitric acid at 0.5 mole/liter, and
acetic acid 0.5 mole/liter in quantities of 150 mL solution per 100
grams of carbon) show promise. Precipitates on the GAC surface
(including iron oxides, sorbed radium
[[Page 59293]]
and radon progeny, including Pb-210) were effectively removed. Removal
efficiencies for Pb-210 ranged from 30 percent to 70 percent and radium
removals from 70 to 90 percent. This work indicates that a viable
system of collecting and cleaning spent GAC material may be feasible,
potentially making GAC a more attractive small systems alternative.
Work supporting programs of this type deserves further consideration.
(vi) The American Water Works Association Research Foundation
Report on Radon Removal Using GAC. The American Water Works Association
Research Foundation (AWWARF 1998a,b) has recently reported on radon
removal by GAC. AWWARF suggests that water systems with design flows
below 70 gallons per minute may want to evaluate GAC and POE GAC as
potential radon removal technologies (AWWARF 1999a), but warns that
they appear to be attractive technologies only for very small systems
with radon influent levels below 5,000 pCi/L, iron and manganese levels
low enough not to warrant pre-treatment, and uranium and radium levels
low enough not to accumulate to levels of concern on the GAC bed (USEPA
1994b). These findings are generally consistent with EPA's findings.
B. Analytical Methods
1. Background
The SDWA directs EPA to set a contaminant's MCL as close to its
MCLG as is ``feasible'', the definition of which includes an evaluation
of the feasibility of performing chemical analysis of the contaminant
at standard drinking water laboratories. Specifically, SDWA directs EPA
to determine that it is economically and technologically feasible to
ascertain the level of the contaminant being regulated in water in
public water systems (Section 1401(1)(C)(i)). NPDWRs are also to
contain ``criteria and procedures to assure a supply of drinking water
which dependably complies with such [MCLs]; including accepted methods
for quality control and testing procedures to insure compliance with
such levels. * * *'' (Section 1401(1)(D)).
To comply with these requirements, EPA considers method performance
under relevant laboratory conditions, their likely prevalence in
certified drinking water laboratories, and the associated analytical
costs. A critical part of the method performance evaluation involves an
analysis of inter-laboratory collaborative study data. This analysis
allows EPA to confirm that the method provides reliable and repeatable
results when used within a given laboratory and when used
``identically'' in other standard laboratories. Other technical
limitations, e.g., sampling and sample preservation requirements,
requirements for non-standard apparatus, and hazards from wastestreams,
are also considered.
In particular, the reliability of analytical methods at the maximum
contaminant level is critical to the implementation and enforcement of
the NPDWR. Therefore, each analytical method considered was evaluated
for accuracy, recovery (lack of bias), and precision (good
reproducibility over the range of MCLs considered). The primary purpose
of this evaluation is to determine:
Whether currently available analytical methods measure
radon in drinking water with adequate accuracy, bias, and precision;
If any newly developed analytical methods can measure
radon in drinking water with acceptable performance;
Reasonable expectations of technical performance for these
methods by analytical laboratories conducting routine analysis at or
near the MCL levels (interlaboratory studies); and
Analytical costs. The selection of analytical methods for
compliance with the proposed regulation includes consideration of the
following factors:
(a) Reliability (i.e., Precision/ accuracy of the analytical
results over a range of concentrations, including the MCL);
(b) Specificity in the presence of interferences;
(c) Availability of adequate equipment and trained personnel to
implement a national compliance monitoring program (i.e., laboratory
availability);
(d) Rapidity of analysis to permit routine use; and
(e) Cost of analysis to water supply systems.
2. Analytical Methods for Radon in Drinking Water
(a) Proposed Analytical Methods for Radon. The analytical methods
described here are the testing procedures EPA identified and evaluated
to insure compliance with the MCL and AMCL. Two analytical methods for
radon in water that fit EPA's criteria for acceptability as compliance
monitoring methods were identified: Liquid Scintillation Counting (LSC)
and the de-emanation method. The LSC method is here defined as Standard
Method 7500-Rn, SM 1995; the de-emanation method is described in the
report, ``Two Test Procedures for Radon in Drinking Water,
Interlaboratory Study'' (USEPA 1987). EPA believes these methods are
technically sound, economical, and generally available for radon
monitoring, and is proposing their use for monitoring to determine
compliance with the MCL or AMCL. The reliability of these methods has
been demonstrated by a history of many years of use by State, Federal,
and private laboratories. Both methods have undergone interlaboratory
collaborative studies (multi-laboratory testing), demonstrating
acceptable accuracy and precision. Thirty-six laboratories participated
in the interlaboratory study for Standard Method 7500-Rn and sixteen
labs in the de-emanation study. The American Society for Testing and
Materials (ASTM) has also published an LSC method (ASTM 1992). Although
its collaborative study (15 participating laboratories) was conducted
at radon sample concentrations greater than 1,500 pCi/L, it is
substantially equivalent to Standard Method (SM) 7500-Rn. EPA is
proposing that ASTM D-5072-92 serve as an alternate method for radon
for both the MCL and AMCL, under the restriction that the quality
controls from SM 7500-Rn are met; namely, that the relative percent
differences between duplicate analyses are less than the 95 percent
confidence level counting uncertainty, as defined in SM 7500-Rn. Table
VIII.B.1 summarizes the proposed analytical methods for radon in
drinking water.
[[Page 59294]]
Table VIII.B.1.--Proposed Analytical Methods for Radon in Drinking Water
----------------------------------------------------------------------------------------------------------------
References (method or page number)
Method -----------------------------------------------------------------
SM ASTM EPA
----------------------------------------------------------------------------------------------------------------
Liquid Scintillation Counting................. 7500-Rn\1\ D 5072-92 ......................................
\2\
De-emanation.................................. ........... ........... EPA 1987 \3\
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Standard Methods for the Examination of Water and Wastewater. 19th Edition Supplement. Clesceri, L., A.
Eaton, A. Greenberg, and M. Franson, eds. American Public Health Association, American Water Works
Association, and Water Environment Federation. Washington, DC. 1996.
\2\ American Society for Testing and Materials (ASTM). Standard Test Method for Radon in Drinking Water.
Designation: D 5072-92. Annual Book of ASTM Standards. Vol. 11.02. 1996.
\3\ Appendix D, Analytical Test Procedure, ``The Determination of Radon in Drinking Water''. In ``Two Test
Procedures for Radon in Drinking Water, Interlaboratory Collaborative Study''. EPA/600/2-87/082. March 1987.
p. 22.
Other analytical methods were evaluated, but they failed at least
one of the criteria described previously. These methods included an
``activated charcoal passive radon collector'', a ``de-gassing Lucas
Cell'' technique (a variant of the de-emanation method), the ``electret
ionization chamber system'', and a ``delay-coincidence liquid
scintillation counting system''. All of these methods are described and
evaluated elsewhere (USEPA 1999g). As described next, if EPA implements
the ``Performance Based Measurement System'' (PBMS) program, then any
method that performs according to specified criteria may be used for
compliance monitoring.
(b) Summary of Methods. Analysis of radon in drinking water by the
LSC method involves preparation of the water sample (ca. 20 mL), which
includes the selective partitioning of radon from the water sample into
a water-immiscible mineral-oil scintillation cocktail and allowance for
equilibration of radon-222 with its progeny. The prepared sample is
then analyzed with an alpha-particle counting system that is optimized
for detecting radon alpha particles. Scintillation counting methods are
discussed later. One of the advantages of transferring the radon from
the water sample into the water-immiscible cocktail is that potential
interferents (other alpha emitters) are left behind in the water phase.
The de-emanation method involves bubbling radon-free helium or aged
air (low background radon) through the water sample into an evacuated
scintillation chamber. After equilibrium is reached (3 to 4 hours),
this chamber is placed in a counter and the resulting scintillations
are counted. This method generally allows measurement of lower level of
radon than does low volume direct liquid scintillation. However, this
method is more difficult to use, requiring specialized glassware and
skilled technicians. Regions of the country with high radon levels in
water (e.g., New Hampshire and Maine) may experience problems with this
method, since the high radon levels in the samples can cause high
backgrounds in the Lucas cell, forcing retirement of the cell for
extended periods.
(c) Alpha Particle Counting Methods for Radon-222. One of the
distinct characteristics of alpha particles is that they exhibit an
intense loss of energy as they pass through matter, due to strong
interactions between the alpha particles and the surrounding atoms.
This intense loss of energy is used in differentiating alpha
radioactivity from other types. Some of the alpha particle's energy
loss is due to its ionization of atoms with which it comes in contact.
Alpha particle detection is based on this phenomenon: when alpha
particles ionize the phosphor coating of a detector, the energized
phosphor ``scintillates'' (or emits light). The resulting light (or
scintillations) are then detected and quantified with an appropriate
detector that is calibrated to determine the concentration of the alpha
emitter of interest. There are variants of detectors that measure these
interactions, but this discussion will focus on the type relevant to
the LSC and Lucas Cell methods.
In scintillation counting, the alpha particle transfers energy to a
scintillator medium, e.g., a phosphor dissolved in a solvent
``cocktail'', which is enclosed within a ``light-tight'' container to
reduce background light. The scintillation cocktail serves two roles:
it contains the phosphor which is involved in quantifying the radon
activity (concentration) and it selectively extracts the radon from the
water sample, leaving behind other alpha emitters that may interfere
with the analysis. The transfer of energy from the radon-derived alpha
particles to the phosphor dissolved in the scintillator medium results
in the production of light (scintillation) of energies characteristic
of the phosphor and with an intensity proportional to the energy
transmitted from the alpha particles, which are the ``signature'' of
radon-222. A ``counter'' records the individual amplified pulses which
are proportional to the number of alpha particles striking the
scintillation detector, which is ultimately proportional to the radon
activity in the original sample. The scintillation cell system used for
the liquid scintillation method is as described previously. The system
used for the de-emanation method is similar, with the exception that a
scintillation flask (``Lucas Cell'', a 100-125 ml metal cup coated on
the inside with a zinc sulfide phosphor and having a transparent
window) replaces the liquid scintillation medium described. A counting
system compatible with the scintillation flask is incorporated to
quantify the radon concentration in the sample. Since radon has a short
decay period (half-life of 3.8 days), correction methods are employed
to account for the radon that decayed between the time of sample
collection and the end of the analysis.
(d) Sampling Collection, Handling, and Preservation. In order to
ensure that samples arriving at laboratories for analysis are in good
condition, EPA is proposing requirements for sample collection,
handling and preservation.
When sampling for dissolved gases like radon, special attention to
sample collection is required. Either the sample collection method
described in SM 7500-Rn, the VOC sample collection method, or one of
the methods described in ``Two Test Procedures for Radon in Drinking
Water, Interlaboratory Collaborative Study'' (USEPA 1987) should be
used. In addition, because dissolved radon tends to accumulate at the
interface between a water sample and some types of plastic containers,
glass bottles with teflon lined caps must be used. Finally, EPA's
assessment of laboratory performance is premised on the assumption that
sample analysis occurs no later than 4 days after collection.
Laboratories unable to comply with this holding time limit may have
difficulty performing within the estimated precision and accuracy
bounds. EPA solicits public comment on the proposed sample collection
procedures for radon in drinking water.
[[Page 59295]]
In discussions between EPA and the water utility industry, concerns
have been expressed about the difficulties in collecting samples and
the requisite skills that may be required. EPA emphasizes that the
skills required to sample for radon are the same as those required to
sample for other currently regulated drinking water contaminants,
namely volatile organic contaminants. In addition, the 1992 EPA
collaborative study mentioned earlier evaluated four sample collection
techniques and found them all capable of providing equivalent results.
Supplementing this study, EPA has reviewed a sampling protocol for
radon in water developed by the Department of Health Services Division
of Drinking Water and Environmental Management (CA DHS 1998). This
protocol employs one of the four techniques evaluated by EPA, the
immersion technique.
Using the immersion technique, the well is purged for 15 minutes by
running the sampling tap, to ensure that a representative sample is
collected. After the purging period, a length of flexible plastic
tubing is attached to the spigot, tap, or other connection, and the
free end of the tubing is placed at the bottom of a small bucket. The
water is allowed to fill the bucket, slowly, until the bucket
overflows. The bucket is emptied and refilled at least once.
Once the bucket has refilled, a glass sample container of an
appropriate size is opened and slowly immersed into the bucket in an
upright position. Once the bottle has been placed on the bottom of the
bucket, the tubing is placed into the bottle to ensure that the bottle
is flushed with fresh water. After the bottle has been flushed, the
tubing is removed while the bottle is resting on the bottom of the
bucket. The cap is placed back on the bottle while the bottle is still
submerged, and the bottle is tightly sealed. As noted in the California
protocol cited earlier, the choice of the sample container is dependent
on the laboratory that will perform the analysis, and will be a
function of the liquid scintillation counter that is employed. If
bottles are supplied by the laboratory, there is no question of what
container to employ.
Once the sealed sample bottle is removed from the bucket, it is
inverted and checked for bubbles that would indicate headspace. If
there are no visible air bubbles, the outside of the sealed bottle is
wiped dry and cap is sealed in place with electrical tape, wrapped
clockwise. After the sample bottle is sealed, a second (duplicate)
sample is collected in the same fashion from the same bucket. The date
and time of the sample collection is recorded for each sample.
As can be surmised from the description, the sample collection
procedures are not particularly labor intensive. Most of the time is
spent allowing the water to overflow the bucket. Likewise, there are no
significant manual skills required.
(e) Skill Considerations for Laboratory Personnel. While neither of
these techniques is difficult relative to standard drinking water
methods, a discussion of the skills required to employ the methods is
appropriate. Given the long history of successful use of the liquid
scintillation counting technique (it has been used in medical
laboratories and environmental research laboratories for well over 30
years), EPA feels confident that State drinking water laboratories will
be able to adequately use these methods. The skills required are
primarily the ability to transfer and mix aliquots of the sample to a
sealed container for further analysis. The counting process is highly
automated and the equipment runs unattended for days, if needed.
The de-emanation process requires somewhat more manual skill. As
noted in the 1991 proposed rule, EPA expects that this technique would
require greater efforts be made to train technicians than for the
liquid scintillation technique. The technique requires that the
counting cell be evacuated to about 10 mTorr pressure and then a series
of stopcocks or valves are manipulated to transfer the radon that is
purged from the sample into the counting cell. Potential problems with
the analysis, such as a high background level of radon that can develop
over the course of the day, or aspirating water into the counting cell,
can be minimized by a well-trained analyst. However, as EPA concluded
in 1991, the Lucas cell technique is not expected to form the sole
basis of a compliance monitoring program for radon in drinking water.
(f) Cost of Performing Analyses. The actual costs of performing
analysis may vary with laboratory, analytical technique selected, the
total number of samples analyzed by a lab, and by other factors. Based
upon information collected in 1991, the average sample cost for radon
in water was estimated to be $50 per sample. EPA recently updated this
cost estimate to $57 per sample (USEPA 1999b) by conducting a similar
survey of drinking water laboratories. The data from the 1991 and 1998
surveys and the descriptive statistics are summarized in Table
VIII.B.2. There was no clear correlation between the estimated price
and the method cited by the laboratory. The 1998 range of prices
brackets those collected by EPA in 1991. It is expected that the
``market forces'' generated by a radon regulation will tend to lower
per sample costs, especially in light of the fact the LSC is very
amenable to automation, with feed capacities of more than 50 samples/
load possible. However, as will be discussed later, there may be short-
term laboratory capacity issues that resist a lowering of per sample
prices.
Table VIII.B.2. Radon Sample Cost Estimate
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Cost Year data
Arbitrary lab No. estimate collected Descriptive statistics for 1991
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................... $30 1991 Mean, $49.80; Median, $47.00; Std. Dev., $18.80; Range, $45; Minimum, $30; Maximum, $75.
2..................................... 44 1991
3..................................... 50 1991
4..................................... 75 1998
Descriptive Statistics for 1998 Data
5..................................... 75 1998 Mean, $56.88; Median, $52.50; Std. Dev., $15.80; Range, $35; Minimum, $40; Maximum, $75.
6..................................... 50 1998
7..................................... 40 1998
8..................................... 75 1998
9..................................... 45 1998
10.................................... 55 1998
11.................................... 75 1998
12.................................... 40 1998
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 59296]]
These cost data are preliminary and may be different in practice
for the following reasons: (a) As the number of experienced
laboratories increases, the costs can be expected to decrease; (b)
analytical costs are determined, to some extent, by the quality control
efforts and quality assurance programs adhered to by the analytical
laboratory; (c) per-sample costs are influenced by the number of
samples analyzed per unit time. EPA solicits comments on its cost
estimates from laboratories experienced in performing these analyses.
(g) Method Detection Limits and Practical Quantitation Levels.
Method detection limits (MDLs) and practical quantitation levels (PQLs)
are two performance measures used by EPA to estimate the limits of
performance of analytic chemistry methods for measuring contaminants in
drinking water. An MDL is the lowest level of a contaminant that can be
measured by a specific method under ideal research conditions. EPA
usually defines the MDL as the minimum concentration of a substance
that can be measured and reported with 99 percent confidence that the
true value is greater than zero. The term MDL is used interchangeably
with minimum detectable activity (MDA) in radionuclide analysis, which
is defined as that amount of activity which in the same counting time,
gives a count which is different from the background count by three
times the standard deviation of the background count. A PQL is the
level at which a contaminant can be ascertained with specified methods
on a routine basis (such as compliance monitoring) by accredited
laboratories, within specified precision and accuracy limits.
The feasibility of implementing an MCL at a particular level is in
part determined by the ability of analytical methods to ascertain
contaminant levels with sufficient precision and accuracy at or near
the MCL. The proposed methods demonstrate good reproducibility and
accuracy at radon concentrations in the range of 150-300 pCi/L (half of
the proposed MCL up to the proposed MCL), as demonstrated in the
results from inter-laboratory studies. In inter-laboratory studies (or
Performance Evaluation studies), prepared samples of known
concentration are distributed for analysis to participating labs, which
have no information on the concentrations of the samples. The results
of the analyses by the participants are compared with the known value
and with each other to estimate the precision and accuracy of both the
methods used and the lab's proficiency in using the method. Table
VIII.B.3 summarizes the statistical results of these inter-laboratory
studies for the proposed methods.
In the 1991 proposed rule, EPA proposed using both the MDL and PQL
as measures of performance for radon analytical methods. EPA also
proposed acceptance limits based on the PQLs that were derived from
these performance evaluation studies. The use of acceptance limits was
confusing to commenters for various reasons. The important issue is the
observation that true analytical method performance is related to
within-laboratory conditions (including counting times in the case of
radiochemicals) and that acceptance limits are based on multi-
laboratory Performance Evaluation studies. For non-radiochemical
contaminants this issue is less troublesome because their PQLs tend to
be ``fixed'' since the MDLs to which they are related reflect optimized
conditions for standard laboratory equipment, whereas for radiochemical
contaminants, counting times can always be increased to increase the
sensitivity and hence lower the appropriate acceptance limits. While
the fifty minute counting time in Standard Method 7500-Rn reflects a
balanced trade-off between time of analysis (and hence the cost of
analysis) and sensitivity, it can obviously be adjusted as needed to
adjust sensitivity. For this reason, commenters objected to the use of
acceptance limits (and, relatedly, PQLs) for radiochemical
contaminants.
EPA agrees that these comments have merit and has decided to seek
comment on two proposals regarding the use of acceptance limits and
PQLs for radon. The first proposal, and the preferred option, is to not
use acceptance limits or PQL for radon, and to adopt the detection
limit as the measure of sensitivity, as done in the 1976 Radionuclides
rule. The existing definition of the detection limit takes into account
the influence of the various factors (efficiency, volume, recovery
yield, background, counting time) that typically vary from sample to
sample. Thus, the detection limit applies to the circumstances specific
to the analysis of an individual sample and not to an idealized set of
measurement parameters, as with acceptance limits and PQLs. The
proposed detection limit is 12 +/- 12 pCi/L, which is based on the
detection limit described in SM 7500-Rn (50 minute counting time, 6 cpm
background, 2.7 cpm/dpm efficiency, and under the energy window
optimization procedure as described in the method). This detection
limit should be applicable to all three approved methods.
One of the reasons for setting a sensitivity standard is to ensure
that laboratories will perform acceptably well on a routine basis at
contaminant levels near the MCL. Internal quality control/quality
assurance procedures are of paramount importance. In addition,
Proficiency Tests are administered by laboratory certifying authorities
to ensure that laboratory performance is acceptable. Currently, the
system for administering proficiency tests and certifying laboratories
is in a state of transition. Up to the recent past, all primacy
entities evaluated laboratory performance based on EPA's Performance
Evaluation (PE) studies program, the National Exposure Research
Laboratory (NERL-LV) Performance Evaluation (PE) Studies program for
radioactivity in drinking water. Currently, the Proficiency Testing
(PT) program for radionuclides is being privatized, i.e., operated by
an independent third party provider accredited by the National
Institute of Standards and Technology (NIST). A lack of uniformity in
state PT requirements may limit laboratory availability for a given
public water system to laboratories that use PT samples approved by the
state. It should be noted that this issue is general and is not
specific to the proposed radon regulation. Efforts to encourage
uniformity in state PT requirements are described in more detail in the
laboratory capacity section.
Under the alternative of using the MDL as the measure of
sensitivity, standard statistical procedures would be used to ensure
that a laboratory has analyzed PT samples acceptably. Since the
national PT program will still be overseen by EPA, the exact procedures
for determining acceptable performance will be developed by EPA and
NIST as the PT program develops. The respective roles of EPA and NIST
in the PT program and discussed further in the Laboratory Approval and
Certification section.
The second proposal is to use the concepts of the acceptance limit
and PQL for radon. Using the standard relationship that PQLs are equal
to 5 to 10 times the MDL yields a PQL for radon in the range of 60 to
240 pCi/L. EPA is proposing a PQL of 100 pCi/L and is seeking comment
on this value. The proposed acceptance limit for a single sample is
5 %. The proposed acceptance limits for triplicate analyses
at the 95th and 99th percent confidence intervals are 6 %
and 9 %, respectively. All of these acceptance limits are
based on the inter-laboratory studies used for the precision and
accuracy results reported in Table
[[Page 59297]]
VIII.B.3. EPA seeks comments on the relative merits between the first
option (the preferred option) of using only an MDL as the measure of
sensitivity and the second option of using a PQL with prescribed
acceptance limits.
Table VIII.B.3.--Inter-laboratory Performance Data for Proposed Radon Analytical Methods \1\
----------------------------------------------------------------------------------------------------------------
Sample
Method Conc. pCi/ Accuracy % Repeatability Reproducibility Bias %
L pCi/L pCi/Ls
----------------------------------------------------------------------------------------------------------------
SM 7500-Rn............................... 111 101-102 9 12 0.7-2.3
SM 7500-Rn............................... 153 102-103 10 16-18 2.3-3.4
De-Emanation............................. 111 114 16 23 14.5
De-Emanation............................. 153 114 17 28 13.7
ASTM D5072-92............................ 1,622 97 2,217 3,541 -2.6
ASTM D5072-92............................ 16,324 95 14,950 44,400 -4.7
ASTM D5072-92............................ 66,324 94 49,190 210,350 -6.0
----------------------------------------------------------------------------------------------------------------
Notes: (1) All results are reported in methods citations found in Table VIII.B.1.
(h) Accuracy and Precision of the Proposed Methods. While SM 7500-
Rn has the best over-all results in precision and accuracy, the de-
emanation method also shows acceptable performance. The ASTM method
shows similar accuracy and bias, but much larger errors in
repeatability (operator precision) and reproducibility (between-lab
precision). Given this inferior demonstration of precision and the
higher concentrations used in the intra-laboratory studies, it may be
argued that this method should not be proposed as a drinking water
method. However, EPA maintains that the method is similar enough in
substance to SM 7500-Rn that it may serve as an alternate method if the
laboratories use the appropriate quality control measures, i.e., ensure
that the relative percent difference between results on duplicate
samples is within the counting uncertainty 95% confidence interval,
where at least 10% of daily samples are duplicates. This procedure is
described in the 4th edition of the Manual for the Certification of
Laboratories Analyzing Drinking Water, Criteria and Procedures Quality
Assurance (EPA 1997). EPA requests comment on including ASTM D5072-92
as an alternate test method.
C. Laboratory Approval and Certification
1. Background
The ultimate effectiveness of the proposed regulations depends upon
the ability of laboratories to reliably analyze contaminants at
relatively low levels. The Drinking Water Laboratory Certification
Program is intended to ensure that approved drinking water laboratories
analyze regulated drinking water contaminants within acceptable limits
of performance. The Certification Program is managed through a
cooperative effort between EPA's Office of Ground Water and Drinking
Water and its Office of Research and Development. The program
stipulates that laboratories analyzing drinking water compliance
samples must be certified by U.S. EPA or the State. The program also
requires that certified laboratories must analyze PT samples, use
approved methods, and States must also require periodic on-site audits.
External checks of performance to evaluate a laboratory's ability
to analyze samples for regulated contaminants within specific limits is
one of the means of judging lab performance and determining whether to
grant certification. Under a PT program, laboratories must successfully
analyze PT samples (contaminant concentrations are unknown to the
laboratory being reviewed) that are prepared by an organization that is
approved by the primacy entity. Successful annual participation in the
PT program is prerequisite for a laboratory to achieve certification
and to remain certified for analyzing drinking water compliance
samples. Achieving acceptable performance in these studies of known
test samples provides some indication that the laboratory is following
proper practices. Unacceptable performance may be indicative of
problems that could affect the reliability of the compliance monitoring
data.
EPA's previous PE sample program and the approaches to determine
laboratory performance requirements are discussed in 63 FR 47097
(September 3, 1998, ``1998 methods update''). In that notice, EPA
amended the regulations to adopt the universal requirement for
laboratories to successfully analyze a PE sample at least once each
year, addressing the fact that the Agency has not specified PE test
frequency requirements in its current drinking water regulations.
Though not specified in the methods update regulation, PE samples may
be provided by EPA, the State, or by a third party with the approval of
the State or EPA. Under the developing PT program, NIST has accredited
a list of PT sample providers, including a radionuclides PT samples
which will apply to radon.
In addition, guidance on minimum quality assurance requirements,
conditions of laboratory inspections, and other elements of laboratory
certification requirements for laboratories conducting compliance
monitoring measurements are detailed in the 4th edition of the Manual
for the Certification of Laboratories Analyzing Drinking Water,
Criteria and Procedures Quality Assurance (EPA 1997), which can be
downloaded via the internet at ``http://www.epa.gov/OGWDW/
labindex.html''.
2. Laboratory Capacity--Practical Availability of the Methods
In order to determine the practical availability of the methods,
EPA considered three major factors. First, the availability of the
major instrumentation was reviewed. Secondly, several laboratories
performing drinking water analyses were contacted to determine their
potential capabilities to perform radon analyses. Lastly, EPA has
reviewed the current status of the privatized Performance Evaluation
studies program and the on-going measure to implement a uniform
program, highlighting the potential impacts on short-term and long-term
laboratory capacity for radon.
3. Laboratory Capacity: Instrumentation
Regarding instrumentation availability, the major instrumentation
required for LSC is the liquid scintillation counter. Automated
counters capable of what that method terms ``automatic spectral
analysis'' are available from at least a dozen suppliers. The de-
emanation Lucas cell apparatus is the same apparatus that has been used
for radium analyses for many years. In light of the wide availability
and the long history of accessibility of the proper instrumentation,
EPA believes that instrument availability should not be an issue for
radon analytical methods.
[[Page 59298]]
4. Laboratory Capacity: Survey of Potential Laboratories
In order to evaluate the availability of laboratory capacity to
perform radon analyses, EPA contacted the drinking water certification
authorities in the States of California, Maryland, and Pennsylvania.
These states were chosen based both on estimated radon occurrence and
the overall status of the programs. Ultimately, EPA collected
information on the availability and relative costs of radon analyses
for drinking water from a total of nine commercial laboratories.
Eight of the nine laboratories that were contacted do perform radon
analyses. All the laboratories were certified in one or more states to
perform radiochemical analyses. When asked what specific methods were
used, the laboratories responded with either the technique (liquid
scintillation counting) or a specific method citation. EPA Method 913
(which later was revised to become SM 7500-Rn) was cited by two of the
laboratories. EPA Method ``EERF Appendix B'' was cited by another
laboratory. The remaining laboratories indicated that they performed
liquid scintillation analyses and could accommodate requests for
methods employing that technique.
When asked about capacity, the laboratories indicated that they
each perform between 100 and 12,000 analyses per year. The latter
figure came from a laboratory that is currently involved in a large
ground water monitoring project in the western United States. The next
largest estimate was 300 samples per year. However, EPA expects that
like any other type of environmental analysis, given a regulatory
``driver'' to perform the analysis, and given the ability of LSC
analysis to be automated, the laboratory capacity will develop in a
timely manner.
EPA's 1992 Annual Report on Radiation Research and Methods
Validation reports the results of a collaborative study on radon
analysis (EPA 1993) and is another useful source of information
regarding potential radon laboratory capacity. This study employed 51
laboratories with the capability to perform liquid scintillation
analyses. This suggests that at that time there already existed a
substantial capacity for these analyses.
Further, the liquid scintillation apparatus is used for other
radiochemical analyses, including tritium. Information from EPA
regarding the performance evaluation program for tritium analyses
suggests that there are approximately 100-200 laboratories with the
necessary equipment. Much of the capacity for tritium analyses could
also be used for radon (EPA 1997). As of September 1997, 136 of 171
participating laboratories achieved acceptable results for tritium.
While the total number of participants and the number achieving
acceptable results vary between studies, the data indicate that there
is a substantial capability for liquid scintillation analysis
nationwide.
5. Laboratory Capacity: Laboratory Certification and Performance
Evaluation Studies
The availability of laboratories is also dependent on laboratory
certification efforts in the individual states with regulatory
authority for their drinking water programs. Until June of 1999, a
major component of many of these certification programs was their
continued participation in the current EPA Water Supply WS performance
evaluation (PE) program, which included radiochemistry PE studies. Due
to resource limitations, EPA has recently privatized EPA's PE programs,
including the Water Supply studies. EPA has addressed this topic in
public stakeholders meetings and in some recent publications, including
Federal Register notices and its June 1997 ``Labcert Bulletin'', which
can be downloaded from the Internet at ``http://www.epa.gov/OGWDW/
labcert3.html''. The decision to privatize the PE studies programs was
announced in the Federal Register on June 12, 1997 (62 FR 32112). This
notice indicated that in the future the National Institute of Standards
and Technology (NIST) would develop standards for private sector PT
sample providers and would evaluate and accredit these providers, while
the actual development and manufacture of PT samples would fall to the
private sector. Further information regarding the respective roles of
EPA and NIST in the privatized PT program can be downloaded from NIST's
homepage at ``http://ts.nist.gov/ts/htdocs/210/210.htm''. EPA believes
that this program will ensure the continued viability of the existing
PT programs, while maintaining government oversight.
This externalized proficiency testing program is in the process of
becoming operational. Under the externalized PT program:
EPA issues standards for the operation of the program,
NIST administers a program to accredit PT sample
providers,
Non-EPA PT sample providers develop and manufacture PT
sample materials and conduct PT studies,
Environmental laboratories purchase PT samples directly
from PT Sample Providers (approved by NIST or the State), and
Certifying authorities certify environmental laboratories
performing sample analyses in support of the various water programs
administered by the States and EPA under the Safe Drinking Water Act.
NIST is in the process of approving a provider for PT samples for
radionuclides, including radon. States also have the option of
approving their own PT sample providers. At this time, it is difficult
to speculate to what degree this externalization of the PT program will
affect short-term and long-term laboratory capacity for radon. EPA
recognizes that initial implementation problems may arise because of
the potential for near-term limited availability of radon PT samples.
EPA also recognizes that insufficient laboratory capacity may lead to a
short-term increase in analytical costs. In the absence of definitive
information regarding the future PT program, EPA solicits public
comment on this matter.
6. Efforts To Ensure a Uniform Proficiency Testing Program: NELAC
The National Environmental Laboratory Accreditation Conference
(NELAC) is also evaluating the issues surrounding privatization of the
SDWA PT program through its proficiency testing committee. NELAC serves
as a voluntary national standards-setting body for environmental
laboratory accreditation, and includes members from both state and
Federal regulatory and non-regulatory programs having environmental
laboratory oversight, certification, or accreditation functions. One of
the goals for the re-designed SDWA PT program is to be consistent with
NELAC's recommendations.
The members of NELAC meet bi-annually to develop consensus
standards through its committee structure. These consensus standards
are adopted by participants for use in their own programs in pursuit of
a uniform national laboratory accreditation program in which
environmental testing laboratories will be able to receive one annual
accreditation that is accepted nationwide. As part of its accreditation
program, NELAC is developing standards for a proficiency testing
program that addresses all fields of testing, including drinking water.
Recent meetings of the Proficiency Testing Committee of NELAC have
reviewed several important issues, including State selection of PT
sample providers and reciprocity between States.
[[Page 59299]]
These issues are described in more detail elsewhere (NELAC 1999a). The
NELAC Proficiency Testing Committee is currently drafting requirements
for radiochemical proficiency testing under SDWA. The June 15, 1999
draft (NELAC 1999b) of its radiochemical proficiency testing
requirements describes radiochemical PT sample designs, acceptance
limits, and other information.
The intent of the NELAC standards setting process is to ensure that
the needs of EPA and state regulatory programs are satisfied in the
context of a uniform national laboratory accreditation program. EPA
recognizes that cooperating with NELAC is an important part of the re-
design of the Proficiency Testing (PT) program for drinking water,
since NELAC provides a means for states, environmental testing
laboratories, and PT study providers to have direct input into the
process. It is hoped that this mutual effort will minimize the
potential disruption in the process of moving from the old EPA PE
program towards the new privatized PT program. EPA shares NELAC's goal
of encouraging uniformity in standards between primacy States regarding
laboratory proficiency testing and accreditation.
7. Laboratory Capacity: Holding Time
The short holding time for radon, 4 days in Method 7500-Rn,
presents concerns relative to the practical availability of laboratory
capacity as well. The 4-day holding time was also the focus of a number
of comments that EPA received in response to the 1991 proposed rule.
Many commenters were concerned that if a local laboratory is not
available, the only alternative will be to send the samples by
overnight delivery to a laboratory elsewhere. However, this situation
is not unique to the analysis of radon. As evidenced during the data
gathering pursuant to the Disinfection By-Products Information
Collection Rule (DBP ICR), several large commercial laboratories
already account for a sizable share of the market for SDWA analyses for
non-radon parameters, including organics, for which the holding times
are often 7 days. Given that a day would be required for shipping the
samples, only three days would remain for the laboratory to perform the
radon analysis (the day on which the sample is collected being ``day
zero''). Some commenters argued that for a large commercial laboratory
serving the water utilities, this short holding time will make it
difficult if not impossible to perform the necessary analyses within
the holding time. However, through common sense scheduling efforts
between the utility and the laboratory, such as not collecting samples
on Thursdays and Fridays, the holding time issue should be able to be
accommodated in light of the ability of the LSC method to be highly
automated.
D. Performance-Based Measurement System (PBMS)
On October 6, 1997, EPA published a Notice of the Agency's intent
to implement a Performance Based Measurement System (PBMS) in all of
its programs to the extent feasible (62 FR 52098). EPA is currently
determining how to adopt PBMS in its drinking water program, but has
not yet made final decisions. When PBMS is adopted in the drinking
water program, its intended purpose will be to increase flexibility in
laboratories in selecting suitable analytical methods for compliance
monitoring, significantly reducing the need for prior EPA approval of
drinking water analytical methods. Under PBMS, EPA will modify the
regulations that require exclusive use of Agency-approved methods for
compliance monitoring of regulated contaminants in drinking water
regulatory programs. EPA will probably specify ``performance
standards'' for methods, which the Agency would derive from the
existing approved methods and supporting documentation. A laboratory
would then be free to use any method or method variant for compliance
monitoring that performed acceptably according to these criteria. EPA
is currently evaluating which relevant performance characteristics
should be specified to ensure adequate data quality for drinking water
compliance purposes. After PBMS is implemented, EPA may continue to
approve and publish compliance methods for laboratories that choose not
to use PBMS. After EPA makes final determinations to implement PBMS in
programs under the Safe Drinking Water Act, EPA would then provide
specific instruction on the specified performance criteria and how
these criteria would be used by laboratories for radon compliance
monitoring.
E. Proposed Monitoring and Compliance Requirements for Radon
1. Background
The monitoring regulation for radon proposed in 1991 by EPA
required that groundwater systems monitor for radon at each entry point
to the distribution system quarterly for one year initially. Monitoring
could be reduced to one sample annually per entry point to the
distribution system if the average of all first quarterly samples was
below the MCL. States could allow systems to reduce monitoring to once
every three years if the system demonstrated that results of all
previous samples collected were below the MCL. The proposal also
allowed States to grant waivers to groundwater systems to reduce the
frequency of monitoring, up to once every 9 years, if States determined
that radon levels in drinking water were consistently and reliably
below the MCL. Comments made in response to the proposed monitoring
requirements for radon were mainly concerned that the proposed
monitoring requirements including number of samples and the frequency
of monitoring did not adequately take into account the effect of
seasonal variations in radon levels on determining compliance. Other
commenters felt that sampling at the entry point of the distribution
system was not representative of exposure to radon, and they suggested
that sampling for radon should be done at the point of use.
Since the 1991 proposal EPA has obtained additional information
from States, the waterworks industry and academia on the occurrence of
radon, including data on the temporal variability of radon. Utilizing
this additional data, the Agency performed extensive statistical
analyses to predict how temporal, analytical variations and variations
between individual wells may affect exposure to radon. The results of
these analyses are described in detail in the report ``Methods,
Occurrence and Monitoring Document for Radon'' in the docket for this
rule (USEPA 1999g). As a result of the new information available, EPA
was able to refine the requirements for monitoring and address the
concerns expressed by the commenters on the 1991 proposal.
The proposed monitoring requirements for radon are consistent with
the monitoring requirements for regulated drinking water contaminants,
as described in the Standardized Monitoring Framework (SMF) promulgated
by EPA under the Phase II Rule of the National Primary Drinking Water
Regulations (NPDWR) and revised under Phases IIB and V. The goal of the
SMF is to streamline the drinking water monitoring requirements by
standardizing them within contaminant groups and by synchronizing
monitoring schedules across contaminant groups. A summary of monitoring
requirements in this proposal, the SMF and the 1991 proposal are
provided in Table VIII.E.1.
[[Page 59300]]
Table VIII.E.1.--Comparison of Monitoring Requirements
------------------------------------------------------------------------
Monitoring requirements for radon
-------------------------------------------------------------------------
1999 Proposal--MCL/ SMF for IOCs in
1991 Proposal AMCL groundwater
------------------------------------------------------------------------
Initial Monitoring Requirements
------------------------------------------------------------------------
Four consecutive quarters of Four consecutive Four consecutive
monitoring at each entry point quarters of quarters of
for one year. Initial monitoring at monitoring at
monitoring was proposed to have each entry point. each entry point
been completed by January 1, Initial for sampling
1999. monitoring must points initially
begin by three exceeding MCL.
years from date
of publication of
the final rule in
Federal Register
of 4.5 years from
date of
publication of
the final rule in
Federal Register
(depending on
effective date
applicable to the
State).
------------------------------------------------------------------------
Routine Monitoring Requirements
------------------------------------------------------------------------
One sample annually if average One sample One sample at each
from four consecutive quarterly annually if sample point
samples taken initially is less average from four during the
than MCL. consecutive initial 3 year
quarterly samples compliance period
is less than MCL/ for groundwater
AMCL, and at the systems for
discretion of sampling points
State. below MCL.
------------------------------------------------------------------------
1991 Proposal 1999 Proposal--MCL SMF for IOCs in
Groundwater
------------------------------------------------------------------------
Reduced Monitoring Requirements
------------------------------------------------------------------------
State may allow groundwater State may allow State may allow
systems to reduce the frequency CWS using groundwater
of monitoring to once every groundwater to systems to reduce
three years provided that they reduce monitoring monitoring
have monitored quarterly in the frequency to:. frequency to:
initial year and completed Once every three Once every three
annual testing in the second years if average years if samples
and third year of the first from four subsequently
compliance period. Groundwater consecutive detects less than
systems must demonstrate that quarterly samples MCL and
all previous analytical samples is less than \1/ determined by
were less than the MCL. 2\ the MCL/AMCL, State to be
provided no ``reliably and
samples exceed consistently
the MCL/AMCL. and below MCL.''
if the system is
determined by
State to be
``reliably and
consistently
below MCL/AMCL ''.
------------------------------------------------------------------------
Monitoring Requirements for Radon
------------------------------------------------------------------------
1991 Proposal 1999 Proposal--MCL/ SMF for IOCs in
AMCL Groundwater
------------------------------------------------------------------------
Increased Monitoring Requirements
------------------------------------------------------------------------
Systems monitoring annually or Systems monitoring If the MCL is
once per three year compliance annually would be exceeded in a
period exceed the radon MCL in required to single sample,
a single sample would be increase the system
required to revert to quarterly monitoring if the required to begin
monitoring until the average of MCL/AMCL for sampling
4 consecutive samples is less radon is exceeded quarterly until
than the MCL. Groundwater in a single State determines
systems with unconnected wells sample, the that it is
would be required to conduct system would be ``reliably and
increased monitoring only at required to consistently''
those wells exceeding the MCL. revert to below MCL.
The State may require more quarterly
frequent monitoring than monitoring until
specified. the average of 4
Systems may apply to the State consecutive
to conduct more frequent samples is less
monitoring than the minimum than the MCL/AMCL.
monitoring frequencies Systems monitoring
specified. once every three
years would be
required to
monitor annually
if the radon
level is less
than MCL/AMCL but
above \1/2\ MCL/
AMCL in a single
sample. Systems
may revert to
monitoring once
per three years
if the average of
the initial and
three consecutive
annual samples is
lees than \1/2\
MCL/AMCL.
CWS using
groundwater with
un-connected
wells would be
required to
conduct increased
monitoring only
at those well
which are
affected.
------------------------------------------------------------------------
[[Page 59301]]
Monitoring Requirements for Radon
------------------------------------------------------------------------
1991 Proposal 1999 Proposal--MCL SMF for IOCs in
Groundwater
------------------------------------------------------------------------
Confirmation Samples
------------------------------------------------------------------------
Where the results of sampling Systems may Where the results
indicate an exceedence of the collect sampling indicate
maximum contaminant level, the confirmation an exceedence of
State may require that one samples as the maximum
additional sample be collected specified by the contaminant
as soon as possible after the State. The level, the State
initial sample was taken [but average of the may require that
not to exceed two weeks] at the initial sample one additional
same sampling point. The and any sample be
results of the of the initial confirmation collected as soon
sample and the confirmation samples will be as possible after
sample shall be averaged and used to determine the initial
the resulting average shall be compliance. sample was taken
used to determine compliance. [but not to
exceed two weeks]
at the same
sampling point.
The results of
the initial
sample and the
confirmation
sample shall be
averaged and the
resulting average
shall be used to
determine
compliance.
------------------------------------------------------------------------
Grandfathering of Data
------------------------------------------------------------------------
If monitoring data collected If monitoring data States may allow
after January 1, 1985 are collected after previous sampling
generally consistent with the proposal of the data to satisfy
requirements specified in the rule are the initial
regulation, than the State may consistent with sampling
allow the systems to use those the requirements requirements
data to satisfy the monitoring specified in the provided the data
requirements for the initial regulation, then were collected
compliance period. the State may after January 1,
allow the systems 1990.
to use those data
to satisfy the
monitoring
requirements for
the initial
compliance period.
------------------------------------------------------------------------
Monitoring Requirements for Radon
------------------------------------------------------------------------
1991 Proposal 1999 Proposal--MCL SMF for IOCs in
Groundwater
------------------------------------------------------------------------
Waivers
------------------------------------------------------------------------
State may grant waiver to The State may The State may
groundwater systems to reduce grant a grant waiver to
the frequency of monitoring, up monitoring waiver groundwater
to nine years. If State to systems to systems after
determines that radon levels in reduce the conducting
drinking water are ``reliably frequency of vulnerability
and consistently'' below the monitoring to up assessment to
MCL. to one sample reduce the
every nine years frequency of
based on previous monitoring, up to
analytical nine years, if
results, State determines
geological that radon levels
characteristics in drinking water
of source water are ``reliably
aquifer and if a and
State determines consistently''
that radon levels below the MCL.
in drinking water System must have
are ``reliably three previous
and samples.
consistently'' Analytical
below the MCL/ results of all
AMCL. previous samples
Analytical results taken must be
of all previous below MCL.
samples taken
must be below \1/
2\ the MCL/AMCL.
------------------------------------------------------------------------
In developing the proposed compliance monitoring requirements for
radon, EPA considered:
(1) The likely source of contamination in drinking water;
(2) The differences between ground water and surface water systems;
(3) The collection of samples which are representative of consumer
exposure;
(4) Sample collection and analytical methods;
(5) The use of appropriate historical data to identify vulnerable
systems and to specify monitoring requirements for individual systems;
(6) The analytical, temporal and intra-system variance of radon
levels;
(7) The use of appropriate historical data and statistical analysis
to establish reduced monitoring requirements for individual systems;
and
(8) The need to provide flexibility to the States to tailor
monitoring requirements to site-specific conditions by allowing them
to:
--Grant waivers to systems to reduce monitoring frequency, provided
certain conditions are met.
--Require confirmation samples for any sample exceeding the MCL/AMCL.
--Allow the use of previous sampling data to satisfy initial sampling
requirements.
--Increase monitoring frequency.
--Decrease monitoring frequency.
2. Monitoring for Surface Water Systems
CWSs relying exclusively on surface water as their water source
will not be required to sample for radon. Systems that rely in part on
ground water would be considered groundwater systems for purposes of
radon monitoring. Systems that use ground water to supplement surface
water during low-flow periods will be required to monitor for radon.
Ground water under the influence of surface water would be considered
ground water for this regulation.
3. Sampling, Monitoring Schedule and Initial Compliance for CWS Using
Groundwater
EPA is retaining the quarterly monitoring requirement for radon as
proposed initially in the 1991 proposal to account for variations such
as sampling, analytical and temporal variability in radon levels.
Results of analysis of data obtained since 1991, estimating
contributions of individual sources of variability to overall variance
in the radon data sets evaluated, indicated that sampling and
analytical variance contributes less than 1 percent to the overall
variance. Temporal variability within single wells accounts
[[Page 59302]]
for between 13 and 18 percent of the variance in the data sets
evaluated, and a similar proportion (12-17 percent) accounts for
variation in radon levels among wells within systems. (USEPA 1999g)
The Agency performed additional analyses to determine whether the
requirement of initial quarterly monitoring for radon was adequate to
account for seasonal variations in radon levels and to identify non-
compliance with the MCL/AMCL. Results of analysis based on radon levels
modeled for radon distribution for ground water sources (USEPA 1999g)
and systems (USEPA 1998a) in the U.S. show that the average of the
first four quarterly samples provides a good indication of the
probability that the long-term average radon level in a given source
would exceed an MCL or AMCL. Tables VIII.E.2 and VIII.E.3 show the
probability of the long-term average radon level exceeding the MCL and
AMCL at various averages obtained from the first four quarterly samples
from a source.
Table VIII.E.2.--The Relationship Between the First-Year Average Radon
Level and the Probability of the Long-Term Radon Average Radon Levels
Exceeding the MCL
------------------------------------------------------------------------
Then the probability that the
If the average of the first four long-term average radon level
quarterly samples from a source is in that source exceeds 300 pCi/
L is
------------------------------------------------------------------------
Less than 50 pCi/L..................... 0 percent.
Between 50 and 100 pCi/L............... 0.5 percent.
Between 100 and 150 pCi/L.............. 0.4 percent.
Between 150 and 200 pCi/L.............. 7.2 percent.
Between 200 and 300 pCi/L.............. 26.8 percent.
------------------------------------------------------------------------
Table VIII.E.3.--The Relationship Between the First-Year Average Radon
Level and the Probability of the Long-Term Radon Average Radon Levels
Exceeding the AMCL
------------------------------------------------------------------------
Then the probability that the
If the average of the first four long-term average radon level
quarterly samples from a source is in that source exceeds 4000 pCi/
L is
------------------------------------------------------------------------
Less than 2,000 pCi/L.................. Less than 0.1 percent.
Between 2,000 and 2,500 pCi/L.......... 9.9 percent.
Between 2,500 and 3,000 pCi/L.......... 15.1 percent.
Between 3,000 and 4,000 pCi/L.......... 32.9 percent.
------------------------------------------------------------------------
The Agency proposes that systems relying wholly or in part on
ground water will be required to initially sample quarterly for radon
for one year at each well or entry point to the distribution system.
All samples will be required to be of finished water, as it enters the
distribution system after any treatment and storage. If the average of
the four quarterly samples at each well is below the MCL/AMCL,
monitoring may be reduced to once a year at State discretion. Systems
may be required to continue monitoring quarterly in instances where the
average of the quarterly samples at each well is below but close to the
MCL/AMCL. The reason for this is that in such cases, there is a good
chance for the long-term average radon level to exceed the MCL/AMCL.
Systems already on-line must begin initial monitoring for
compliance with the MCL/AMCL by the compliance dates specified in the
rule (i.e., 3 years after the date of promulgation or 4.5 years after
the date of promulgation). Monitoring requirements for new sources will
be determined by the State. The compliance dates are discussed in
detail in Section VII.E, Compliance Dates.
The Agency is retaining the requirement as proposed in 1991 to
sample at the entry point to the distribution system. Sampling at the
entry point allows the system to account for radon decay during storage
and removal during the treatment process. The reason for not allowing
sampling at the point of use is that this approach would not take into
account higher exposure levels that may be encountered at locations
upstream from the sampling site. In addition, sampling at the entry
point will make it easier to identify and isolate possible contaminant
sources within the system. The sample collection sites at each entry
point to the distribution system and the monitoring schedule requiring
sampling for four consecutive quarters proposed herein is consistent
with the SMF. This approach streamlines monitoring since the same
sampling points can be used for the collection of samples for other
source-related contaminants.
EPA specifically requests comments on the following aspects of the
proposed monitoring requirements:
The appropriateness of the proposed initial monitoring
period.
The availability and capabilities of laboratories to
analyze radon samples collected during the initial compliance period.
The Agency recognizes that short-term implementation problems may arise
to meet the initial monitoring deadline because of the potential
limited availability of radon performance evaluation (PE) samples used
to evaluate and certify laboratories.
The appropriateness of the proposed number and frequency
of samples required to monitor for radon.
The designation of sampling locations at the entry point
to the distribution system which is located after any treatment and
storage. Comments are also solicited on the definition of sampling
points that are representative of consumer exposure.
Designating sampling locations and frequencies that permit
simultaneous monitoring for all regulated contaminants, whenever
possible and advantageous. The proposed sampling locations would be
such that the same sampling locations could be used for the collection
of samples for other source-related contaminants such as the volatile
organic chemicals and inorganic chemicals, which would simplify sample
collection efforts.
EPA also solicits comments on whether the monitoring requirements
should include additional monitoring for radon as a source of consumer
exposure from the distribution system. Results of investigations in
Iowa indicate that in some instances, pipe scale deposited in the
distribution system can be a source of exposure to radon. Community
ground water systems could be required to collect an additional sample
from the distribution system during the initial year of monitoring, at
the same time the entry point sample is collected, and continue to
collect samples from the distribution system annually if it is shown
that exceedence of the MCL/AMCL is caused by the release of radon from
deposited scale in the interior of the distribution system. Results
obtained from distribution samples could provide information on the
extent and frequency
[[Page 59303]]
of occurrence of radon originating from distribution systems.
4. Increased/Decreased Monitoring Requirements
Initial compliance with the MCL/AMCL will be determined based on an
average of four quarterly samples taken at individual sampling points
in the initial year of monitoring. Systems with averages exceeding the
MCL/AMCL at any sampling point will be deemed to be out of compliance.
Systems in a non-MMM State exceeding the MCL will have the option to
develop and implement a local MMM program in accordance with the
timeframe discussed in Section VII.E, Compliance Dates without
receiving a MCL violation.
Systems exceeding the MCL/AMCL will be required to monitor
quarterly until the average of four consecutive samples is less than
the MCL/AMCL. Systems will then be allowed to collect one sample
annually if the average from four consecutive quarterly samples is less
than the MCL/AMCL and if the State determines that the system is
reliably and consistently below the MCL/AMCL.
Systems will be allowed to reduce monitoring frequency to once
every three years (one sample per compliance period) per well or
sampling point, if the average from four consecutive quarterly samples
is less than \1/2\ the MCL/AMCL and the State determines that the
system is reliably and consistently below the MCL/AMCL. As shown in
Tables VIII.E.2 and VIII.E.3, EPA believes that there is sufficient
margin of safety to allow for this since there is a small probability
that long term average radon levels will exceed the MCL/AMCL.
Systems monitoring annually that exceed the radon MCL/AMCL in a
single sample will be required to revert to quarterly monitoring until
the average of four consecutive samples is less than the MCL/AMCL.
Community ground water systems with unconnected wells will be required
to conduct increased monitoring only at those wells exceeding the MCL/
AMCL. Compliance will be based on the average of the initial sample and
three consecutive quarterly samples.
Systems monitoring once per compliance period or less frequently
which exceed \1/2\ the MCL/AMCL (but do not exceed the MCL/AMCL) in a
single sample would be required to revert to annual monitoring. Systems
may revert to monitoring once every three years if the average of the
initial and three consecutive annual samples is less than \1/2\ the
MCL/AMCL. Community ground water systems with unconnected wells will be
required to conduct increased monitoring only at those wells exceeding
the MCL/AMCL.
States may grant a monitoring waiver reducing monitoring frequency
to once every nine years (once per compliance cycle) provided the
system demonstrates that it is unlikely that radon levels in drinking
water will occur above the MCL/AMCL. In granting the monitoring waiver,
the State must take into consideration factors such as the geological
area where the water source is located, and previous analytical results
which demonstrate that radon levels do not occur above the MCL/AMCL.
The monitoring waiver will be granted for up to a nine year period.
(Given that all previous samples are less than \1/2\ the MCL/AMCL, then
it is highly unlikely that the long-term average radon levels would
exceed the MCL/AMCL.)
If the analytical results from any sampling point are found to
exceed the MCL/AMCL (in the case of routine monitoring) or \1/2\ the
MCL/AMCL (in the case of reduced monitoring), the State may require the
system to collect a confirmation sample(s). The results of the initial
sample and the confirmation sample(s) shall be averaged and the
resulting average shall be used to determine compliance.
EPA specifically requests comments on the following aspects of the
proposed monitoring requirements :
Allowing systems at State discretion, to reduce monitoring
frequencies as long as the system demonstrates that its radon levels
are maintained below the MCL/AMCL. For example, all community ground
water systems would be required to collect one sample from each entry
point to the distribution system (located after any treatment and
storage) quarterly at first and annually after compliance is
established. MCL/AMCL exceedence would trigger reverting to quarterly
sampling until compliance with the MCL/AMCL is reestablished.
Compliance is reestablished when the average of four consecutive
quarterly samples is below the MCL/AMCL.
Allowing States to reduce monitoring requirements to not
less than once every three years if the average radon levels from four
consecutive quarterly samples is less than \1/2\ the MCL/AMCL, and the
State determines that the radon levels in the drinking water are
reliably and consistently below \1/2\ the MCL/AMCL. A single sample
exceeding \1/2\ the MCL/AMCL would trigger reverting to sampling
annually. Comments are solicited on the criteria allowing the utility
to revert to monitoring once every three years if the average of the
initial and three consecutive annual samples is less than \1/2\ the
MCL/AMCL.
Factors affecting State discretion to grant waivers. In
addition, the Agency solicits comments on the advisability of reducing
the monitoring frequency up to nine years between samples. Comments are
solicited on the requirement that all previous samples (that might be
used to identify systems which are very unlikely to exceed the MCL/
AMCL) must be below \1/2\ the MCL/AMCL in order for a system to qualify
for a waiver.
Allowing States to require the collection of confirmation
samples to verify initial sample results as specified by the State, and
to use the average of the initial sample and the confirmation samples
to determine compliance.
5. Grandfathering of Data
At a State's discretion, sampling data collected since the proposal
could be used to satisfy the initial sampling requirements for radon,
provided that the system has conducted a monitoring program and used
analytical methods that meet proposal requirements. The Agency wants to
provide water suppliers with the opportunity to synchronize their radon
monitoring program with monitoring for other contaminants and to get an
early start on their monitoring program if they wish to do so.
The Agency solicits comments on the advisability of allowing the
use of monitoring data obtained since the proposal to satisfy the
initial monitoring requirements.
IX. State Implementation
This section describes the regulations and other procedures and
policies States have to adopt, or have in place, to implement today's
proposed rule. States must continue to meet all other conditions of
primacy in 40 CFR part 142.
Section 1413 of the SDWA establishes requirements that a State must
meet to obtain or maintain primacy enforcement responsibility (primacy)
for its public water systems. These include: (1) Adopting drinking
water regulations that are no less stringent than Federal NPDWRs in
effect under Section 1412(b) of the Act; (2) adopting and implementing
adequate procedures for enforcement; (3) keeping records and making
reports available on activities that EPA requires by regulation; (4)
issuing variances and exemptions (if allowed by the State) under
conditions no less stringent than allowed by Sections 1415 and 1416;
(5) adopting
[[Page 59304]]
and being capable of implementing an adequate plan for the provision of
safe drinking water under emergency situations; and (6) adopting
authority for administrative penalties.
40 CFR part 142 sets out the specific program implementation
requirements for States to obtain primacy for the public water supply
supervision (PWSS) program, as authorized under SDWA 1413 of the Act.
In addition to meeting the basic primacy requirements, States may be
required to adopt special primacy provisions pertaining to a specific
regulation. States are required by 40 CFR 142.12 to include these
regulation-specific provisions in an application for approval of their
program revisions. To maintain primacy for the PWS program and to be
eligible for interim primacy enforcement authority for future
regulations, States must adopt today's rule, when final, along with the
special primacy requirements discussed next. Interim primacy
enforcement authority allows States to implement and enforce drinking
water regulations once State regulations are effective and the State
has submitted a complete and final primacy revision application. Under
interim primacy enforcement authority, States are effectively
considered to have primacy during the period that EPA is reviewing
their primacy revision application.
A. Special State Primacy Requirements
In addition to adopting drinking water regulations at least as
stringent as the regulations described in the previous sections, EPA
requires that States adopt certain additional provisions related to
this regulation, in order to have their drinking water program revision
application approved by EPA. States have two options when implementing
this rule. States may adopt the AMCL and implement a State-wide MMM
program plan or States may adopt the MCL. If a State chooses to adopt
the MCL, CWSs in that State have the option to develop and implement a
State-approved local MMM program plan and comply with the AMCL.
To ensure that the State program includes all the elements
necessary for a complete enforcement program, EPA is proposing that 40
CFR part 142 be amended to require the following in order to obtain
primacy for this rule:
(1) Adoption of the promulgated Radon Rule, and
(2) One of the following, depending on which regulatory option the
State chooses to adopt:
(a) If a State chooses to develop and implement a State-wide MMM
program plan and adopt the AMCL, the primacy application must contain a
copy of the State-wide MMM program plan meeting the four criteria in 40
CFR Part 141 Subpart R and the following: a description of how the
State will make resources available for implementation of the State-
wide MMM program plan, and a description of the extent and nature of
coordination between interagency programs (i.e., indoor radon and
drinking water programs) on development and implementation of the MMM
program plan, including the level of resources that will be made
available for implementation and coordination between interagency
programs (i.e., indoor air and drinking water programs).
(b) If a State chooses to adopt the MCL, the primacy application
must contain a description of how the State will implement a program to
approve local CWS MMM program plans prepared to meet the criteria
outlined in 40 CFR Part 141 Subpart R. In addition, the primacy
application must contain a description of how the State will ensure
local CWS MMM program plans are implemented and the extent and nature
of coordination between interagency programs (i.e., indoor radon and
drinking water programs) on development and implementation of the MMM
program, including the level of resources that will be made available
for implementation and coordination between interagency programs (i.e.,
indoor air and drinking water programs), as well as, a description of
the reporting and record keeping requirements for the CWSs.
States are required to submit their primacy revision application
packages by two years from the date of publication of the final rule in
the Federal Register. For States adopting the AMCL, EPA approval of a
State's primacy revision application is contingent on submission of and
EPA approval of the State's MMM program plan. Therefore, EPA is
proposing to require submission of State-wide MMM program plans as part
of the complete and final primacy revision application. This will
enable EPA to review and approve the complete primacy application in a
timely and efficient manner in order to provide States with as much
time as possible to begin to implement MMM programs. In accordance with
Section 1413(b)(1) of SDWA and 40 CFR 142.12(d)(3), EPA is to review
primacy applications within 90 days. Therefore, although the SDWA
allows 180 days for EPA review and approval of MMM program plans, EPA
expects to review and approve State primacy revision applications for
the AMCL, including the State-wide MMM program plan, within 90 days of
submission to EPA.
EPA is proposing that States notify CWSs of their decision to adopt
the MCL or AMCL at the time they submit their primacy application
package to EPA (24 months after publication of the final rule). If a
State adopts the MCL, CWSs choosing to implement a local CWS MMM
program and comply with the AMCL will be required to have completed
initial monitoring, notify the State of their intention, and begin
developing a plan 4 years after the rule is final. EPA is particularly
concerned that these CWSs have sufficient time to develop MMM program
plans with local input and allow for State approval. Therefore, it is
EPA's expectation that States will be submitting complete and final
primacy revision applications by 24 months from the date of publication
of the final rule in Federal Register. In reviewing any State requests
for extensions of time in submitting primacy revision applications, EPA
will consider whether sufficient time will be provided to CWSs to
develop and get State approval of their local MMM program plans prior
to implementation.
B. State Record Keeping Requirements
Today's rule does not include changes to the existing recordkeeping
provisions required by 40 CFR 142.14. MMM record keeping requirements
will be addressed in each State's primacy revision application
submission to meet the special primacy requirements for radon (40 CFR
142.16).
C. State Reporting Requirements
Currently States must report to EPA information under 40 CFR 142.15
regarding violations, variances and exemptions, enforcement actions and
general operations of State public water supply programs.
In accordance with the Safe Drinking Water Act (SDWA), EPA is to
review State MMM programs at least every five years. For the purposes
of this review, the States with EPA-approved MMM program plans shall
provide written reports to EPA in the second and fourth years between
initial implementation of the MMM program and the first 5-year review
period, and in the second and fourth years of every subsequent 5-year
review period. EPA will review these programs to determine whether they
continue to be expected to achieve risk reduction of indoor radon using
the information provided in the two biennial reports. EPA requests
comment on this approach. These reports are required to include the
following information:
[[Page 59305]]
A quantitative assessment of progress towards meeting the
required goals described in Section VI. A., including the number or
rate of existing homes mitigated and the number or rate of new homes
built radon-resistant since implementation of the States' MMM program:
and
A description of accomplishments and activities that
implement the program strategies outlined in the implementation plan
and in the two required areas of promoting increased testing and
mitigation of existing homes and promoting increased use of radon-
resistant techniques in construction of new homes.
If goals were defined as rates, the State must also
provide an estimate of the number of mitigations and radon-resistant
new homes represented by the reported rate increase for the two-year
period.
If the MMM program plan includes goals for promoting
public awareness of the health effects of indoor radon, testing of
homes by the public; testing and mitigation of existing schools; and
construction of new public schools to be radon-resistant, the report is
also required to include information on results and accomplishments in
these areas.
EPA will use this information in discussions and consultations with
the State during the five-year review to evaluate program progress and
to consider what modifications or adjustments in approach may be
needed. EPA envisions this review process will be one of consultation
and collaboration between EPA and the States to evaluate the success of
the program in achieving the radon risk reduction goals outlined in the
approved programs. If EPA determines that a MMM program in not
achieving progress towards its goals, EPA and the State shall
collaborate to develop modifications and adjustments to the program to
be implemented over the five year period following the review. EPA will
prepare a summary of the outcome of the program evaluation and the
proposed modification and adjustments, if any, to be made by the State.
States that submit a letter to the Administrator by 90 days after
publication of the final rule committing to develop an MMM program
plan, must submit their first 2-year report by 6.5 years from
publication of the final rule. For States not submitting the 90-day
letter, but choosing subsequently to submit an MMM program plan and
adopt the AMCL, the first 2-year report must be submitted to EPA by 5
years from publication of the final rule. States shall make available
to the public each of these two-year reports, as well as the EPA
summaries of the five-year reviews of a State's MMM program, within 90
days of completion of the reports and the review.
In primacy States without a State-wide MMM program, the States
shall provide a report to EPA every five-years on the status and
progress of CWS MMM programs towards meeting their goals. The first of
such reports would be due 5 years after CWSs begin implementing a local
MMM program which is 5.5 years from publication of the final rule.
D. Variances and Exemptions
Section 1415 of the SDWA authorizes the State to issue variances
from NPDWRs (the term ``State'' is used in this preamble to mean the
State agency with primary enforcement responsibility, or ``primacy,''
for the public water supply system program or EPA if the State does not
have primacy). The State may issue a variance under Section 1415(a) if
it determines that a system cannot comply with an MCL due to the
characteristics of its source water, and on condition that the system
install BAT. Under Section 1415(a), EPA must propose and promulgate its
finding identifying the best available technology, treatment
techniques, or other means available for each contaminant, for purposes
of Section 1415 variances, at the same time that it proposes and
promulgates a maximum contaminant level for such contaminant. EPA's
finding of BAT, treatment techniques, or other means for purposes of
issuing variances may vary, depending upon the number of persons served
by the system or for other physical conditions related to engineering
feasibility and costs of complying with MCLs, as considered appropriate
by the EPA. The State may not issue a variance to a system until it
determines among other things that the variance would not pose an
unreasonable risk to health (URTH). EPA has developed draft guidance,
``Guidance in Developing Health Criteria for Determining Unreasonable
Risks to Health'' (USEPA 1990) to assist States in determining when an
unreasonable risk to health exists. EPA expects to issue final guidance
for determining when URTH levels exist later this year. When a State
grants a variance, it must at the same time prescribe a schedule for
(1) compliance with the NPDWR and (2) implementation of such additional
control measures as the State may require.
Under Section 1416(a), the State may exempt a public water system
from any MCL and/or treatment technique requirement if it finds that
(1) due to compelling factors (which may include economic factors), the
system is unable to comply or develop an alternative supply, (2) the
system was in operation on the effective date of the MCL or treatment
technique requirement, or, for a newer system, that no reasonable
alternative source of drinking water is available to that system, (3)
the exemption will not result in an unreasonable risk to health, and
(4) management or restructuring changes cannot be made that would
result in compliance with this rule. Under Section 1416(b), at the same
time it grants an exemption the State is to prescribe a compliance
schedule and a schedule for implementation of any required interim
control measures. The final date for compliance may not exceed three
years after the NPDWR effective date except that the exemption can be
renewed for small systems for limited time periods.
EPA will not list ``small systems variance technologies'', as
provided in Section 1415(e)(3) of the Act, since EPA has determined
that affordable treatment technologies exist for all applicable system
sizes and water quality conditions. As stated in this Section of the
Act, if the Administrator finds that small systems can afford to comply
through treatment, alternate water source, restructuring, or
consolidation, according to the affordability criteria established by
the Administrator, then systems are not eligible for small systems
variances. Small systems will, however, still be able to apply for
``regular'' variances and exemptions, pursuant to Sections 1415 and
1416 of the Act.
E. Withdrawing Approval of a State MMM Program
If EPA determines that a State MMM program is not achieving
progress towards its MMM goals, and the State repeatedly fails to
correct, modify and adjust implementation of its MMM program after
notice by EPA, EPA may withdraw approval of the State's MMM program
plan. The State will be responsible for notifying CWSs of the
Administrator's withdrawal of approval of the State-wide MMM program
plan. The CWSs in the State would then be required to comply with the
MCL within one year from date of notification, or develop a State-
approved CWS MMM program plan. EPA will work with the State to develop
a State process for review and approval of CWS MMM program plans that
meet
[[Page 59306]]
the required criteria and establish a time frame for submittal of
program plans by CWSs that choose to continue complying with the AMCL.
The review process will allow for local public participation in
development and review of the program plan.
X. What Do I Need To Tell My Customers? Public Information
Requirements
A. Public Notification
Sections 1414(c)(1) and (c)(2) of the SDWA, as amended, require
that public water systems notify persons served when violations of
drinking water standards occur. EPA recently proposed to revise the
current public notification regulations to incorporate new statutory
provisions enacted under the 1996 SDWA amendments (64 FR 25963, May 13,
1999). The purpose of public notification is to alert customers in a
timely manner to potential risks from violations of drinking water
standards and the steps they should take to avoid or minimize such
risks.
Today's regulatory action would add violation of the radon NPDWR to
the list of violations requiring public notice under the May 13, 1999,
proposed public notification rule. Today's action would make three
changes to the proposed public notification rule.
First, Appendix A to Subpart Q would be modified to
require a Tier 2 public notice for violations of the MCL and AMCL for
all community water systems. Under the proposed rule, Tier 2 public
notices would be required for violations and situations with potential
to have serious adverse effects on human health. Tier 2 public notices
must be distributed within 30 days after the violation is known, and
must be repeated every three months until the violation is resolved.
Second, Appendix A would also be modified to require a
Tier 3 public notice for all radon monitoring and testing procedure
violations and for violations of the Multimedia Mitigation (MMM)
Program Plan. Tier 3 public notices must be distributed within a year
of the violation and could, at the water system's option, be included
in the annual Consumer Confidence Report (CCR).
Third, Appendix B to Subpart Q would be modified to add
standard health effects language, which public water systems are
required to use in their notices when violations of the AMCL or MMM
occur. EPA proposes that the standard health effects language for these
violations, to be included in CCR annual reports and public notices.
The language for violation of the (A)MCL would be as follows: ``People
who use drinking water containing radon in excess of the (A)MCL for
many years may have an increased risk of getting lung and stomach
cancer.'' The language for violation of the MMM would be as follows:
``Your water system is not complying with requirements to promote the
reduction of lung cancer risks from radon in indoor air, which is a
problem in some homes. Radon is a naturally occurring radioactive gas
which may enter homes from the surrounding soil and may also be present
in drinking water. Because your system is not complying with applicable
requirements, it may be required to install water treatment technology
to meet more stringent standards for radon in drinking water. The best
way to reduce radon risk is to test your home's indoor air and, if
elevated levels are found, hire a qualified contractor to fix the
problem. For more information, call the National Safety Council's Radon
Hotline at 1-800-SOS-RADON.'' The standard health effects language
public water systems are to use in their public notice would be
identical to that used in the annual CCR.
The final public notification rule is expected to be published
around December, 1999, well in advance of the August, 2000, deadline
for the final radon regulation. The final public notification
requirements for radon, therefore, will be published with the final
radon rule. The Agency will republish the tables in Appendices A and B
to Subpart Q of Part 141 with all necessary changes in the final rule.
B. Consumer Confidence Report
Section 1414(d) of the SDWA requires that all community water
systems provide annual water quality reports (or consumer confidence
reports (CCRs)) to their customers. In their reports, systems must
provide, among other things, the levels and sources of all detected
contaminants, the potential health effects of any contaminant found at
levels that violate EPA or State rules, and short educational
statements on contaminants of particular interest.
Today's action updates the standard CCR rule requirements in
subpart O and adds special requirements that reflect the multimedia
approach of this rule. The intent of these provisions is to assist in
clearer communication of the relative risks of radon in indoor air from
soil and from drinking water, and to encourage public participation in
the development of the State or CWS MMM program plans. Systems that
detect radon at a level that violates the A/MCL would have to include
in their report a clear and understandable explanation of the violation
including: the length of the violation, actions taken by the system to
address the violation, and the potential health effects (using the
language proposed today for Appendix C to subpart O: ``People who use
drinking water containing radon in excess of the (A)MCL for many years
may have an increased risk of getting lung and stomach cancer''). This
approach is comparable to that used for other drinking water
contaminants.
In addition, recognizing the novelty of the MMM approach and the
interest that consumers may have in participating in the design of the
MMM program, today's action also proposes that any system that has
ground water as a source must include information in its report in the
years between publication of the final rule and the date by which
States, or systems, will be required to implement an MMM program. This
information would include a brief educational statement on radon risks,
explaining that the principal radon risk comes from radon in indoor
air, rather than drinking water, and for that reason, radon risk
reduction efforts may be focused on indoor air rather than drinking
water. This information will also note that many States and systems are
in the process of creating programs to reduce exposure to radon, and
encourage readers to call the Radon Hotline (800-SOS-RADON) or visit
EPA's radon web site (www.epa.gov/iaq/radon) for more information. A
system would be able to use language provided in the proposed rule by
EPA or could chose to tailor the wording to its specific local
circumstances in consultation with the primacy agency. EPA recognizes
that this creates a slight additional burden on community water system
operators, but believes that the value of strong public support for,
and participation in, the creation of the MMM program outweighs this
burden. EPA also recognizes that this notice may provoke some
confusion, since CCRs would alert consumers to the risks presented by a
contaminant which most systems have never monitored in their water,
although the notice would state that the system would be testing and
would provide customers with the results. EPA is requesting comment on
this proposed notice.
Finally, the Agency will republish the tables in Appendices A, B,
and C to Subpart O of Part 141 with all necessary changes in the final
rule.
[[Page 59307]]
Risk Assessment and Occurrence
XI. What Is EPA's Estimate of the Levels of Radon in Drinking
Water?
A. General Patterns of Radon Occurrence
Radon levels in ground water in the United States are generally
highest in New England and the Appalachian uplands of the Middle
Atlantic and Southeastern States. There are also isolated areas in the
Rocky Mountains, California, Texas, and the upper Midwest where radon
levels in ground water tend to be higher than the United States
average. The lowest ground water radon levels tend to be found in the
Mississippi Valley, lower Midwest, and Plains States. The following map
shows the general patterns of radon occurrence in those States for
which data are available.
BILLING CODE 6560-50-P
[[Page 59308]]
[GRAPHIC] [TIFF OMITTED] TP02NO99.008
BILLING CODE 6560-50-C
[[Page 59309]]
In addition to large-scale regional variation, radon levels in
ground water vary significantly over a smaller area. Local differences
in geology tend to greatly influence the patterns of radon levels
observed at specific locations. (This means, for example, that not all
radon levels in New England are high and not all radon levels in the
Gulf Coast region are low). Over small distances, there is often no
consistent relationship between radon levels in ground water and
uranium or other radionuclide levels in the ground water or in the
parent bedrock (Davis and Watson 1989). Similarly, no significant
geographic correlation has been found between radon levels in
groundwater systems and the levels of other inorganic contaminants.
Radon may be found in groundwater systems where other contaminants (for
example, arsenic) also occur. However, finding a high (or low) level of
radon does not indicate that a high (or low) level of other
contaminants will also be found. Similarly, there is little evidence
that radon occurrence is correlated with the presence of organic
pollutants. In estimating the costs of radon removal, EPA has taken
into account the fact that other contaminants, such as iron and
manganese, may also be present in the water. High levels of iron and
manganese may complicate the process of radon removal and increase the
costs of mitigation.
Radon is released rapidly from surface water. Therefore, radon
levels in supplies that obtain their water from surface sources (lakes
or reservoirs) are very low compared to groundwater levels.
Because of its short half life, there are relatively few man-made
sources of radon exposure in ground water. The most common man-made
sources of radon ground water contamination are phosphate or uranium
mining or milling operations and wastes from thorium or radium
processing. Releases from these sources can result in high ground water
exposures, but generally only to very limited populations; for
instance, to persons using a domestic well in a contaminated aquifer as
a source of potable water (USEPA 1994a).
B. Past Studies of Radon Levels in Drinking Water
A number of studies of radon levels in drinking water were
undertaken in the 1970s and early 1980s. Most of these studies were
limited to small geographic areas, or addressed systems that were not
representative of community systems throughout the U.S. The first
attempt to develop a comprehensive understanding of radon levels in
public water supplies was the National Inorganics and Radionuclides
Survey (NIRS), which was undertaken by the EPA in 1983-1984. As part of
NIRS, radon samples were analyzed from 1,000 community groundwater
systems throughout the United States. The size distribution of systems
sampled was the same as the size distribution of groundwater systems in
U.S., and the geographic distribution was approximately consistent with
the regional distribution of systems. Because of the limited number of
samples, however, the number of radon measurements in some States was
quite small. Table XI.B.1 summarizes the regional patterns of radon in
drinking water supplies as seen in the NIRS database.
Table XI.B.1.--Radon in Community Ground Water Systems by Region (All System Sizes)
----------------------------------------------------------------------------------------------------------------
Geometric
Region Arithmetic mean Geometric mean standard
(pCi/L) (pCi/L) deviation (pCi/L)
----------------------------------------------------------------------------------------------------------------
Appalachian............................................ 1,127 333 4.76
California............................................. 629 333 3.09
Gulf Coast............................................. 263 125 3.38
Great Lakes............................................ 278 151 3.01
New England............................................ 2,933 1,214 3.77
Northwest.............................................. 222 161 2.23
Plains................................................. 213 132 2.65
Rocky Mountains........................................ 607 361 2.77
----------------------------------------------------------------------------------------------------------------
Source: USEPA 1999g.
Note: These distributions are described in two ways. First, the arithmetic means (average values) are given. In
addition, the geometric mean and geometric standard deviation are given. This approach is taken because the
distributions of radon in groundwater systems are not ``normal'' bell-shaped curves. Instead, like many
environmental data sets, it was found that the logarithms of the radon concentrations were normally
distributed (``lognormal distribution.'') The geometric mean corresponds to the center of a bell-shaped
``normal'' distribution when radon concentrations are expressed in logarithms. The geometric standard
deviation is a measure of the spread of the bell-shaped curve, expressed in logarithmic form.
The NIRS has the disadvantage that the samples were all taken from
within the water distribution systems, making estimation of the
naturally occurring influent radon levels difficult. In addition, the
NIRS data provide no information to allow analysis of the variability
of radon levels over time or within individual systems. Thus, while the
NIRS data provide statistically valid estimates of radon levels in the
systems that were sampled, they do not adequately represent radon
levels in some individual States, especially in large systems.
The NIRS data formed the basis for EPA's first estimates of the
levels of radon in community groundwater systems in the United States
(Wade Miller 1990). They formed the basis for estimating the impacts of
EPA's 1991 Proposed Rule. These estimates were updated in 1993, using
improved statistical methods to estimate the distributions of radon in
different size systems (Wade Miller 1993.)
C. EPA's Most Recent Studies of Radon Levels in Ground Water
EPA's current re-evaluation of radon occurrence in ground water
(USEPA 1999g) uses data from a number of additional sources to
supplement the NIRS information and to develop estimates of the
national distribution of radon in community ground water systems of
different sizes. EPA gathered data from 17 States where radon levels
were measured at the wellhead, rather than in the distribution systems.
The Agency then evaluated the differences between the State (wellhead)
data and the NIRS (distribution system) data. These differences were
then used to adjust the NIRS data to make them more representative of
ground water radon levels in the States where no direct
[[Page 59310]]
measurements at the wellhead had been made. EPA solicits any additional
data on radon levels in community water systems, particularly in the
largest size categories.
Table XI.C.1 summarizes EPA's latest estimates of the distributions
of radon levels in ground water supplies of different sizes. It also
provides information on the populations exposed to radon through
community water systems (CWS). In this table, radon levels and
populations are presented for systems serving population ranges from 25
to greater than 100,000 customers. The CWSs are broken down into the
following system size categories:
Very very small systems (25-500 people served), further
subdivided into 25-100 and 101-500 ranges, in response to comments
received on the 1991 proposal;
Very small systems (501-3,300 people);
Small systems (3,301-10,000 people);
Medium systems (10,001-100,000 people); and
Large systems (greater than 100,000 people).
Table XI.C.1.--Radon Distributions in Community Groundwater Systems
----------------------------------------------------------------------------------------------------------------
System Size (Population Served)
-----------------------------------------------------------------------------------
25-100 101-500 501-3,300 3,301-10,000 >10,000 All systems
----------------------------------------------------------------------------------------------------------------
Total Systems............... 14,651 14,896 10,286 2,538 1,536 43,907
Geometric Mean Radon Level, 312 259 122 124 132 232
pCi/L......................
Geometric Standard Deviation 3.0 3.3 3.2 2.3 2.3 3.0
Arithmetic Mean............. 578 528 240 175 187 442
Population Served (Millions) 0.87 3.75 14.1 14.3 55.0 88.1
Radon Level, pCi/L.......... Proportions of Systems Exceeding Radon Levels (percent)
100......................... 84.7 78.7 56.9 60.4 62.9 74.0
300......................... 51.4 45.1 22.1 14.3 16.2 39.0
500......................... 33.6 29.1 11.4 4.6 5.5 24.2
700......................... 23.4 20.3 6.8 1.8 2.3 16.5
1000........................ 14.7 12.9 3.6 0.6 0.8 10.2
2000........................ 4.7 4.4 0.8 0.0 0.1 4.9
4000........................ 1.1 1.1 0.1 0.0 0.0 0.8
----------------------------------------------------------------------------------------------------------------
Sources: USEPA 1999g; Safe Drinking Water Information System (1998).
Systems were broken down in this fashion because EPA's previous
analyses have shown that the distributions of radon levels are
different in different size systems. In the updated occurrence
analysis, insufficient data were available to accurately assess radon
levels in various subcategories of largest systems. Thus, data from the
two largest size categories were pooled to develop exposure estimates.
D. Populations Exposed to Radon in Drinking Water
Based on data from the Safe Drinking Water Information System
(SDWIS), the Agency estimates that approximately 88.1 million people
were served by community ground water systems in the United States in
1998. Using the data in Table XI.C.1, systems serving more than 500
people account for approximately 95 percent of the population served by
community ground water systems, even though they represent only about
33 percent of the total active systems. The largest systems (those
serving greater than 10,000 people) serve approximately 62.5 percent of
the people served by community ground water systems, even though they
account for only 3.5 percent of the total number of systems.
As noted previously, the average radon levels vary across the
system size categories. As shown in Table XI.C.1, the average system
geometric mean radon levels range from approximately 120 pCi/L for the
larger systems to 312 pCi/L for the smallest systems. The average
arithmetic mean values for the various system size categories range
from 175 pCi/L to 578 pCi/L, and the population-weighted arithmetic
mean radon level across all the community ground water supplies is 213
pCi/L (calculations not shown). The bottom panel of Table XI.C.1 shows
the proportions of the systems with average radon levels greater than
selected values.
Table XI.D.1 presents the total populations in homes served by
community ground water systems at different radon levels, broken down
by system size category. These data show that approximately 20 percent
of the total population served by community ground water systems are
served by systems where the average radon levels entering the system
exceed 300 pCi/L and 64 percent of this population are served by
systems with average radon levels above 100 pCi/L. Less than one-tenth
of one percent of the population is served by systems obtaining their
water from sources with radon levels above 4,000 pCi/L.
Table XI.D.1.--Population Exposed Above Various Radon Levels by Community Ground Water System Size (Thousands)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Very very small Very Small Small Medium Large
Radon level (pCi/L) --------------------------------------------------------------------------------- Total
25-100 101-500 501-3,300 3,301-10K 10K-100K >100K
--------------------------------------------------------------------------------------------------------------------------------------------------------
4,000.................................................... 9.4 46 20 0.2 0.9 0.4 77.2
2,000.................................................... 41 183 119 5.7 21.7 11.0 381
1,000.................................................... 128 541 513 85.5 289 147 1,695
700...................................................... 202 848 962 267 859 436 3,558
500...................................................... 290 1,210 1,620 672 2,070 1,050 6,893
300...................................................... 445 1,880 3,140 2,080 6,060 3,070 16,641
100...................................................... 733 3,290 8,080 8,760 23,400 11,900 56,054
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 59311]]
XII. What Are the Risks of Radon in Drinking Water and Air?
A. Basis for Health Concern
The potential hazard of radon was first identified in the 1940s
when an increased incidence of lung cancer in Bohemian underground
miners was shown to be associated with inhalation of high levels of
radon-222 in the mines. By the 1950s, the hazard was shown to be due
mainly to the short half-life progeny of radon-222. Based on a clear
relationship between radon exposure and risk of lung cancer in a number
of studies in miners, national and international health organizations
have concluded that radon is a human carcinogen. In 1988, the
International Agency for Research on Cancer (IARC 1988) convened a
panel of world experts who agreed unanimously that sufficient evidence
exists to conclude that radon causes cancer in humans and in
experimental animals. The Biological Effects of Ionizing Radiation
(BEIR) Committee (NAS 1988, NAS 1999a), the International Commission on
Radiological Protection (ICRP 1987), and the National Council on
Radiation Protection and Measurement (NCRP 1984) also have reviewed the
available data and agreed that radon exposure causes cancer in humans.
EPA has concurred with these determinations and classified radon in
Group A, meaning that it is considered by EPA to be a human carcinogen
based on sufficient evidence of cancer in humans. After smoking, radon
is the second leading cause of lung cancer deaths in the United States
(NAS 1999a).
Most of the radon that people are exposed to in indoor and outdoor
air comes from soil. However, radon in ground water used for drinking
or other indoor purposes can also be hazardous. When radon in water is
ingested, it is distributed throughout the body. Some of it will decay
and emit radiation while in the body, increasing the risk of cancer in
irradiated organs (although this increased risk is significantly less
than the risk from inhaling radon). Radon dissolved in tap water is
released into indoor air when it is used for showering, washing or
other domestic uses, or when the water is stirred, shaken, or heated
before being ingested. This adds to the airborne radon from other
sources, increasing the risk of lung cancer (USEPA 1991, 1994a; NAS
1999b).
B. Previous EPA Risk Assessment of Radon in Drinking Water
1. EPA's 1991 Proposed Radon Rule
Because initial information on the cancer risks of radon came from
studies of underground miners exposed to very high radon levels, not
much consideration was given to non-occupational radon exposure until
recently. As new miner groups at lower radon exposure levels were added
to the data base, it became evident that radon exposures in indoor air,
outdoor air, and drinking water might be important sources of risk for
the U.S. population. In 1991, as part of developing a regulation for
radionuclides and radon in water as required by the 1986 Safe Drinking
Water Act, EPA drafted the Radon in Drinking Water Criteria Document
(USEPA 1991) to assess the ingestion and inhalation risk associated
with exposure to radon in drinking water. EPA estimated that a person's
risk of fatal cancer from lifetime use of drinking water containing one
picocurie of radon per liter (1 pCi/L) is close to 7 chances in 10
million (7 x 10--7). Based on this and other
considerations, EPA proposed a rule for regulating radon levels in
public water systems (56 FR 33050).
2. SAB Concerns Regarding the 1991 Proposed Radon Rule
The Radiation Advisory Committee of EPA's Science Advisory Board
(SAB) reviewed EPA's draft criteria document and proposed rule and
identified a number of issues that had not been adequately addressed,
including: (a) Uncertainties associated with the models, model
parameters, and final risk estimates; (b) high exposure from water at
the point of use (e.g., shower); (c) risks from the disposal of
treatment byproducts; and (d) occupational exposure due to regulation
and removal of radon in drinking water. The SAB recommended that EPA
investigate these issues before finalizing the radon rule. The EPA
considered SAB's recommendations in developing the current proposal.
3. 1994 Report to Congress
In 1992, Congress passed Public Law 102-389 (the Chafee-Lautenberg
Amendment to EPA's Appropriation Bill). This law directs the
Administrator of the EPA to report to Congress on EPA's findings
regarding the risks of human exposure to radon and their associated
uncertainties, the costs for controlling or mitigating that exposure,
and the risks posed by treating water to remove radon.
In response to the SAB's comments and the Chafee-Lautenberg
Amendment, EPA drafted a report entitled Uncertainty Analysis of Risks
Associated with Radon in Drinking Water (USEPA 1993b) and presented it
to the SAB in February 1993. This document evaluated the variability
and uncertainty in each of the factors needed to calculate human cancer
risk from water-borne radon in residences served by community
groundwater systems, and used Monte Carlo simulation techniques to
derive quantitative confidence bounds for the risk estimates for each
of the exposure routes to water-borne radon. In addition, the report
summarized the risk estimates from exposure to radon in indoor and
outdoor air.
Based on the data available at the time, EPA estimated that the
total number of fatal cancers that will occur as a result of exposure
to water-borne radon in homes supplied by community groundwater systems
was 192 per year. EPA noted that the risk from water-borne radon is
small compared to the risk of soil-derived radon in indoor air (13,600
lung cancer cases per year) or in outdoor air (520 lung cancer deaths
per year) (USEPA 1992b, 1993b).
The EPA included the findings of this uncertainty analysis with the
SAB review comments in the Report to the United States Congress on
Radon in Drinking Water: Multimedia Risk and Cost Assessment of Radon
(USEPA 1994a). This report also included an assessment of the risk from
exposure to radon at drinking water treatment facilities. The SAB
reviewed the report prepared by EPA, and commended the EPA's
methodologies employed in the uncertainty analysis and the exposure
assessment of radon at the point of use (e.g. showering). However, the
SAB stated that the estimates of risk from ingested radon may have
additional uncertainties in dose estimation and in the use of primarily
the atomic bomb survivor exposure (gamma emission with low linear
energy transfer) in deriving the organ-specific risk per unit dose for
from radon and progeny (alpha particle emission with high linear energy
transfer). The SAB also questioned EPA's estimates of the number of
community water supplies affected, and the extrapolation of the risk of
lung cancer associated with the high radon exposures of uranium miners
to the low levels of exposure experienced in domestic environments. The
SAB recommended that the Agency use a relative risk orientation as an
important consideration in making risk reduction decisions on all
sources of risks attributable to radon. Based on the
[[Page 59312]]
comments and recommendations of the SAB, EPA revised several of the
distributions used in the Monte Carlo analysis and finalized the
Uncertainty Analysis of Risks Associated with Exposure to Radon in
Drinking Water (USEPA 1995).
C. NAS Risk Assessment of Radon in Drinking Water
1. NAS Health Risk and Risk-Reduction Benefit Assessment Required by
the 1996 Amendments to the Safe Drinking Water Act
The 1996 amendments to the Safe Drinking Water Act required EPA to
arrange with the National Academy of Sciences (NAS) to conduct a risk
assessment of radon in drinking water and an assessment of the health-
risk reduction benefits associated with various measures to reduce
radon concentrations in indoor air. The law also directed EPA to
promulgate an alternative maximum contaminant level (AMCL) if the
proposed MCL is less than the concentration of radon in water
``necessary to reduce the contribution of radon in indoor air from
drinking water to a concentration that is equivalent to the national
average concentration of radon in outdoor air.''
2. Charge to the NAS Committee
In accordance with the requirements of the 1996 amendments to the
SDWA, in February 1997, EPA funded the NAS National Research Council to
establish a multidisciplinary committee of the Board of Radiation
Effects Research. This Committee on Risk Assessment of Exposure to
Radon in Drinking Water (the NAS Radon in Drinking Water committee) was
charged to use the best available data and methods to provide the
following:
(a) The best estimate of the central tendency of the transfer
factor for radon from water to air, along with an appropriate
uncertainty range,
(b) Estimates of unit cancer risk (i.e., the risk from lifetime
exposure to water containing 1 pCi/L) for the inhalation and ingestion
exposure routes, both for the general population and for subpopulations
within the general population (e.g., infants, children, pregnant women,
the elderly, individuals with a history of serious illness) that are
identified as likely to be at greater risk due to exposure to radon in
drinking water than the general population,
(c) Unit cancer risks from inhalation exposure for people in
different smoking categories,
(d) Descriptions of any teratogenic and reproductive effects in men
and women due to exposure to radon in drinking water,
(e) Central estimates for a population-weighted average national
ambient (outdoor) air concentration for radon, with an associated
uncertainty range.
The NAS Radon in Drinking Water committee was also asked to
estimate health risks that might occur as the result of compliance with
a primary drinking water regulation for radon. The committee was to
assess the health risk reduction benefits associated with various
mitigation measures to reduce radon levels in indoor air.
3. Summary of NAS Findings
The NAS completed its charge and issued a report entitled ``Risk
Assessment of Radon in Drinking Water'' (NAS 1999b). The NAS report
provides detailed descriptions of the methods and assumptions employed
by the NAS Radon in Drinking Water committee in completing its
evaluation. The following text provides a summary of the NAS report.
(a) National Average Ambient Radon Concentration. Because radon
levels in outdoor air vary from location to location, the NAS Radon in
Drinking Water committee concluded that available data are not
sufficiently representative to calculate a population-weighted annual
average ambient radon concentration. Based on the data that are
available, the NAS Radon in Drinking Water committee concluded that the
best estimate of an unweighted arithmetic mean radon concentration in
ambient (outdoor) air in the United States is 15 Bq/m3
(equal to 0.41 pCi/L of air), with a confidence range of 14 to 16 Bq/
m3 (0.38-0.43 pCi/L air).
(b) Transfer Factor. The relationship between the concentration of
radon in water and the average indoor air concentration of water-
derived radon is described in terms of the transfer factor (pCi/L in
air per pCi/L in water). Most researchers who have investigated this
variable in residences find that it can be described as a lognormal
distribution of values, most conveniently characterized by the
arithmetic mean (AM) and the standard deviation (Stdev), or by the
geometric mean (GM) and the geometric standard deviation (GSD). The NAS
Radon in Drinking Water committee performed an extensive review of both
measured and calculated values of the transfer factor in residences,
with the results summarized in the following Table XII.1:
Table XII.1.--Measured and Modeled Transfer Factors
----------------------------------------------------------------------------------------------------------------
Approach AM Stdev GM GSD
----------------------------------------------------------------------------------------------------------------
Measured....................... 0.87 x 10-4 1.2 x 10-4 0.38 x 10-4 3.3
Modeled........................ 1.2 x 10-4 2.4 x 10-4 0.55 x 10-4 3.5
----------------------------------------------------------------------------------------------------------------
a Calculated from, GM and GSD.
The committee concluded that there is reasonable agreement between
the average value of the transfer factor estimated by the two
approaches, and identified 1 in 10,000 (1.0 x 10-4) as the
best central estimate of the transfer factor for residences, with a
confidence bound of about 0.8 to 1.2 x 10-4. This central
tendency value is the same as has been used in previous assessments
(USEPA 1993b, 1995).
Based on this transfer factor, the NAS committee concluded that the
AMCL for radon in drinking water would be 150,000 Bq/m3 (
about 4,000 pCi/L). That is, a concentration of 4,000 pCi/L of radon in
water is expected to increase the concentration of radon in indoor air
by an amount equal to that in outdoor air.
(c) Biologic Basis of Risk Estimation. Both the BEIR VI Report (NAS
1999a) and their report on radon in drinking water (NAS 1998b)
represent the most definitive accumulation of scientific data gathered
on radon since the 1988 NAS BEIR IV (NAS 1988). These committees'
support for the use of linear non-threshold relationship for radon
exposure and lung cancer risk came primarily from their review of the
mechanistic information on alpha-particle-induced carcinogenesis,
including studies of the effect of single versus multiple hits to cell
nuclei.
The NAS BEIR VI Committee (NAS 1999a) conducted an extensive review
of information on the cellular and molecular mechanism of radon-induced
cancer in order to help support the assessment of cancer risks from low
levels of radon exposure. In the BEIR VI
[[Page 59313]]
report (NAS 1999a), the NAS concluded that there is good evidence that
a single alpha particle (high-linear energy transfer radiation) can
cause major genomic changes in a cell, including mutation and
transformation that potentially could lead to cancer. Alpha particles,
such as those that are emitted from the radon decay chain, produce
dense trails of ionized molecules when they pass through a cell,
causing cellular damage. Alpha particles passing through the nucleus of
a cell can damage DNA. In their report, the BEIR VI Committee noted
that even if substantial repair of the genomic damage were to occur,
``the passage of a single alpha particle has the potential to cause
irreparable damage in cells that are not killed''. Given the convincing
evidence that most cancers originate from damage to a single cell, the
Committee went on to conclude that ``On the basis of these [molecular
and cellular] mechanistic considerations, and in the absence of
credible evidence to the contrary, the Committee adopted a linear non-
threshold model for the relationship between radon exposure and lung-
cancer risk. The Committee also noted that epidemiological data
relating to low radon exposures in mines also indicate that a single
alpha track through the cell may lead to cancer. Finally, while not
definitive by themselves, the results from residential case-control
studies provide some direct support for the conclusion that
environmental levels of radon pose a risk of lung cancer. However, the
BEIR VI Committee recognized that it could not exclude the possibility
of a threshold relationship between exposure and lung cancer risk at
very low levels of radon exposure.
The NAS Committee on radon in drinking water (NAS 1999b) reiterated
the finding of the BEIR VI Committee's comprehensive review of the
issue, that a ``mechanistic interpretation is consistent with linear
non-threshold relationship between radon exposure and cancer risk''.
The committee noted that the ``quantitative estimation of cancer risk
requires assumptions about the probability of an exposed cell becoming
transformed and the latent period before malignant transformation is
complete. When these values are known for singly hit cells, the results
might lead to reconsideration of the linear no-threshold assumption
used at [email protected] EPA recognizes that research in this area is on-going
but is basing its regulatory decisions on the best currently available
science and recommendations of the NAS that support use of a linear
non-threshold relationship. EPA recognizes that research in this area
is on-going but is basing its regulatory decisions on the best
currently available science and recommendations of the NAS that support
use of a linear non-threshold relationship.
(d) Unit Risk from Inhalation Exposure to Radon Progeny. The
calculation of the unit risk from inhalation of radon progeny derived
from water-borne radon depends on four key variables: (1) The transfer
factor that relates the concentration of radon in air to the
concentration in water, (2) the equilibrium factor (the level of radon
progeny present compared to the theoretical maximum amount), (3) the
occupancy factor (the fraction of full time that a person spends at
home) and (4) the risk of lung cancer per unit exposure (the risk
coefficient). The values utilized by NAS for each of these factors are
summarized next.
Transfer Factor
The NAS Radon in Drinking Water committee (NAS 1999b) reviewed
available data and concluded that the best estimate of the transfer
factor is 1.0 x 10-4 pCi/L air per pCi/L water.
Equilibrium Factor
At radiological equilibrium, 1 pCi/L of radon in air corresponds to
a concentration of 0.010 Working Levels (WL) of radon progeny. One WL
is defined as any combination of radioactive chemicals that result in
an emission of 1.3 x 105 MeV of alpha particle energy. One
WL is approximately the total amount of energy released by the short-
lived progeny in equilibrium with 100 pCi of radon. Under typical
household conditions, processes such as ventilation and plating out of
progeny prevent achievement of equilibrium, and the level of radon
progeny present is normally less than 0.010 WL. The equilibrium factor
(EF) is the ratio of the alpha energy actually present in respirable
air compared to the theoretical maximum at equilibrium. Based on a
review of measured values in residences, USEPA (1993b, 1995) identified
a value of 0.4 as the best estimate of the mean, with a credible range
of 0.35 to 0.45. NAS (1999a, 1999b) reviewed the data and also selected
a value of 0.4 as the most appropriate point estimate of EF.
Occupancy Factor
The occupancy factor (the fraction of time that a person spends at
home) varies with age and occupational status. Studies on the occupancy
factor have been reviewed by EPA (USEPA 1992b, 1993b, 1995), who found
that a value of 0.75 is the appropriate point estimate of the mean with
a credible range of 0.65-0.80. Based on a review of available data,
both the BEIR VI committee (NAS 1999a) and the NAS Radon in Drinking
Water committee (NAS 1999b) identified an occupancy factor of 0.7 as
the best estimate to employ in calculation of the inhalation unit risk
from inhalation of radon progeny.
Risk of Lung Cancer Death per Unit Exposure (Risk Coefficient)
There are extensive data on humans (mainly from studies of
underground miners) establishing that inhalation exposure to radon
progeny causes increased risk of lung cancer (NAS 1999a, 1999b). The
basic approach used by NAS to quantify the risk of fatal cancer
(specifically death from lung cancer) from inhalation of radon progeny
in air was to employ empirical dose-response relationships derived from
studies of humans exposed to radon progeny in the environment. The most
recent quantitative estimate of the risk of lung cancer associated with
inhalation of radon progeny has been conducted by the BEIR VI committee
(NAS 1999a), and this analysis was employed by the NAS Radon in
Drinking Water committee (NAS 1999b). The BEIR VI committee reviewed
all of the most current data from studies of humans exposed to radon,
including cohorts of underground miners and residents exposed to radon
in their home, as well as studies in animals and in isolated cells.
Because of differences in exposure level and duration, studies of
residential radon exposure would normally be preferable to studies of
miners for quantifying risk to residents from radon progeny in indoor
air. However, the BEIR VI committee found that the currently available
epidemiological studies of residents exposed in their homes are not
sufficient to develop reliable quantitative exposure-risk estimates
because (a) the number of subjects is small, (b) the difference between
exposure levels is limited, and (c) cumulative radon exposure estimates
are generally incomplete or uncertain. Therefore, the BEIR VI committee
focused their analysis on studies of radon-exposed underground miners.
The method used by the BEIR VI committee was essentially the same
as used previously by the BEIR IV committee (NAS 1988), except that the
database on radon risk in underground miners is now much more
extensive, including 11 cohorts of underground miners, which, in all,
include about 2,700 lung cancers among 68,000
[[Page 59314]]
miners, representing nearly 1.2 million person-years of observations.
Details of these 11 cohorts are presented in the NAS BEIR VI Report
(NAS 1999a). For historical reasons, the measure of exposure used in
these studies is the Working Level Month (WLM), which is defined as 170
hours of exposure to one Working Level (WL) of radon progeny.
Based on evidence that risk per unit exposure increased with
decreasing exposure rate or with increasing exposure duration (holding
cumulative exposure constant), the BEIR VI committee modified the
previous risk model to include a term to account for this ``inverse
dose rate'' effect. Because the adjustment could be based on either the
concentration of radon progeny or the duration of exposure, there are
two alternative forms of the preferred model--the ``exposure-age-
concentration'' model, and the ``exposure-age-duration'' model. For
brevity, these will generally be referred to here as the
``concentration'' and ``duration'' models.
Mathematically, both models can be represented as:
RR=1+ERR=1+(5-14+15-24
15-24+25+
25+)
(1)
Where:
RR=relative risk of lung cancer in a person due to above-average radon
exposure compared to the average background risk for a similar person
in the general population
ERR=Excess relative risk (the increment in risk due to the above-
average exposure to radon)
=exposure-response parameter (excess relative risk per WLM)
5-14=exposures (WLM) incurred from 5-14 years
prior to the current age
15-24=exposures (WLM) incurred from 15-24 years
prior to the current age
25+=exposures (WLM) incurred 25 or more years
prior to the current age
15-24=time-since-exposure factor for risk from
exposures incurred 15-24 years or more before the attained age
25+=time-since-exposure factor for risk from
exposures incurred 25 or more years or more before the attained age
=effect-modification
factor for attained age
=effect-modification factor for exposure
rate or exposure duration
The BEIR VI committee used a two-stage approach for combining
information from the 11 miner studies to derive parameters for the
concentration and duration risk models. First, estimates of model
parameters were derived for each study cohort, and then population-
weighted averages of the parameters were calculated across studies to
derive an overall estimate that takes variation between and within
cohorts into account. The results of the pooled analysis of all of the
miner data indicated that, for a given level of exposure to radon, the
excess relative risk of lung cancer decreases with increasing time
since exposure, decreases as a function of increased attained age,
increases with increasing duration of exposure, and decreases with
increasing exposure rate (the inverse dose rate effect).
The BEIR VI committee applied the risk models to 1985-89 U.S.
mortality data to estimate individual and population risks from radon
in air. At the individual level, the committee estimated the lifetime
excess relative risk (ERR), which is the percent increase in the
lifetime probability of lung cancer death from indoor radon exposure.
For population risks, the committee estimated attributable risk (AR),
which indicates the proportion of lung-cancer deaths that theoretically
may be reduced by reduction of indoor radon concentrations to outdoor
levels.
Extrapolation From Mines to Homes
Because of a number of potential differences between mines and
homes, exposures to equal levels of radon progeny may not always result
in equal doses to lung cells. The ratio of the dose to lung cells in
the home compared to that in mines is described by the K factor. Based
on the best data available at the time, NAS (1991) had previously
concluded that the dose to target cells in the lung was typically about
30 percent lower for a residential exposure compared to an equal WLM
exposure in mines (i.e., K = 0.7). The BEIR VI committee re-examined
the issue of the relative dosimetry in homes and mines. In light of new
information regarding exposure conditions in home and mine
environments, the committee concluded that, when all factors are taken
into account, the dose per WLM is nearly the same in the two
environments (i.e., a best estimate for the K-factor is about 1) (NAS
1999a). The major factor contributing to the change was a downward
revision in breathing rates for miners. Thus, for calculation of risks
from residential exposures, Equation 1 can be applied directly without
adjustment.
Combined Effect of Smoking and Radon
Because of the strong influence of smoking on the risk from radon,
the BEIR VI committee (NAS 1999a) evaluated risk to ever-smokers and
never-smokers separately. The committee had information on 5 of the
miner cohorts, from which they concluded that the combined effects of
radon and smoking were more than additive but less than multiplicative.
As a best estimate the committee determined that never-smokers should
be assigned a relative risk coefficient () about twice that
for ever-smokers, in each of the two models defined previously. This
means that the attributable risk, or the proportion of all lung cancers
attributable to radon, is about twice as high for never-smokers as
ever-smokers. Nevertheless, because the incidence of lung cancer is
much greater for ever-smokers than never-smokers, the probability of a
radon induced lung cancer is still much higher for ever-smokers. This
higher risk in ever-smokers arises from the synergism between radon and
cigarette smoke in causing lung cancer.
Based on the BEIR VI lifetime relative risk results, the NAS Radon
in Drinking Water committee (NAS 1999b) calculated the lifetime risk
(per Bq/m3 air) for each of the two models using the
following basic equation:
Excess lifetime risk=(Baseline risk)* (LRR-1)
Where LRR=lifetime relative risk
Baseline lung cancer risk values used by the NAS Radon in Drinking
Water committee (NAS 1999b) are summarized in Table XII.2.
Table XII.2.--Baseline Lung Cancer Risk
------------------------------------------------------------------------
Smoking Ever- Never-
Gender prevalence smokers \1\ smokers
------------------------------------------------------------------------
Male............................. 0.58 0.116 0.0091
Female........................... 0.42 0.068 0.0059
------------------------------------------------------------------------
\1\ Ever-smokers were defined as persons who had smoked at least 100
cigarettes in their entire life (CDC 1995).
[[Page 59315]]
The NAS Radon in Drinking Water committee (NAS 1999b) adopted the
average of the results from each of the two models as the best estimate
of lifetime risk from radon progeny.
Results: Inhalation Unit Risk for Water-Borne Radon Progeny
Based on the inputs and approaches summarized in the previous
sections, NAS calculated the inhalation unit risk for radon progeny, by
smoking category, with the results described in Table XII.3:
Table XII.3.--Lifetime Unit Risk
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inhalation risk
Smoking category per Bq/m \3\ in air per pCi/L in water Lifetime (yrs) Annual unit risk coefficient (per
(per pCi/L in water) WLM)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Combined.......................... 1.6 x 10-4 5.93 x 10-7 74.9 7.92 x 10-9 5.49 x 10-4
Ever Smokers...................... 2.6 x 10-4 9.63 x 10-7 73.7 1.31 x 10-8 9.07 x 10-4
Never Smokers..................... 0.5 x 10-4 1.85 x 10-7 76.1 2.43 x 10-9 1.68 x 10-4
--------------------------------------------------------------------------------------------------------------------------------------------------------
The NAS Radon in Drinking Water committee (NAS 1999b) estimated
that the uncertainty around the inhalation risk coefficient for radon
progeny can be characterized by a lognormal distribution with a GSD of
1.2 (based on the duration model) to 1.3 (based on the concentration
model). This corresponds to an uncertainty range for the combined
population of about 3.4 x 10-4 to 8.1 x 10-4 lung cancer deaths per
person per WLM.
Inhalation Risks to Subpopulations, Including Children
The NAS Radon in Drinking Water committee concluded that, except
for the lung-cancer risk to smokers, there is insufficient information
to permit quantitative evaluation of radon risks to susceptible sub-
populations such as infants, children, pregnant women, elderly and
seriously ill persons.
The BEIR VI committee (NAS 1999a) noted that there is only one
study (tin miners in China) that provides data on whether risks from
radon progeny are different for children, adolescents, and adults.
Based on this study, the committee concluded that there was no clear
indication of an effect of age at exposure, and the committee made no
adjustments in the lung cancer risk model for exposures received at
early ages.
(e) Unit Risk for Ingestion Exposure. The calculation of the unit
risk from ingestion of radon in water depends on three key variables:
(1) The amount of radon-containing water ingested, (2) the fraction of
radon lost from the water before ingestion, and (3) the risk to the
tissues per unit of radon absorbed into the body (risk coefficient).
The values utilized by NAS for each of these factors are summarized
next.
Water Ingestion Rate
EPA (USEPA 1993b, 1995) performed a review of available data on the
amount of water ingested by residents. In brief, water ingestion can be
divided into two categories: direct tap water (that which is ingested
as soon as it is taken from the tap) and indirect tap water (water used
in cooking, for making coffee, etc.). Available data indicate nearly
all radon is lost from indirect tap water before ingestion, so only
direct tap water is of concern. Based on available data (Pennington
1983; USEPA 1984; Ershow and Cantor 1989, USEPA 1993b, USEPA 1995)
scientists estimated that the mean of the direct tap water ingestion
rate was 0.65 liters per day (L/day), with a credible range of about
0.57 to 0.74 L/day. Based mainly on this analysis, NAS (1999b)
identified 0.6 L/day as the best estimate of direct tap water intake,
and utilized this value in the calculation of the unit risk from radon
ingestion. This value includes direct tap water ingested at all
locations, and so includes both residential and non-residential
exposures.
The analysis conducted for radon in drinking water uses radon-
specific estimates of water consumption, based on guidance from the NAS
Radon in Drinking Water committee. Based on radon's unique
characteristics, this approach is different from the Agency's approach
to other drinking water contaminants.
In general, in calculating the risk for all other water
contaminants, EPA uses 2 liters per day as the average amount of water
consumed by an individual. For radon, the Agency used 0.6 liters per
day to estimate the risks of radon ingestion. The NAS ingestion risk
number is derived from an average risk/radiation coefficient, an
average drinking water ingestion rate, and an average life expectancy.
NAS chose to use an ingestion rate of 0.6 liter per day, based on an
assumption that only 0.6 liters of the ``direct'' water will retain
radon. Since radon is very readily released during normal household
water use, we assume that radon in water used for indirect purposes
(cooking, making coffee, etc) is released before drinking. Only direct
water (drinking from tap directly) is used to estimate ingestion risk.
The Agency solicits comments on this approach to estimating the
ingestion risk of radon in drinking water, particularly the assumption
of 0.6 liters per day direct consumption.
Fraction of Radon Remaining During Water Transfer From the Tap
Because radon is a gas, it tends to volatilize from water as soon
as the water is discharged from the plumbing system into any open
container or utensil. As would be expected, the fraction of radon
volatilized before consumption depends on time, temperature, surface
area-to-volume ratio, and degree of mixing or aeration. A previous
analysis by EPA (USEPA 1995) identified a value of 0.8 as a reasonable
estimate of the mean fraction remaining before ingestion, with an
estimated credibility interval about the mean of 0.7 to 0.9. Because
data are so sparse, and in order to be conservative, NAS assumed a
point estimate of 1.0 for this factor (NAS 1999b).
Risk per Unit of Radon Absorbed (Risk Coefficient)
The NAS Radon in Drinking Water committee reviewed a number of
publications on the risk from ingestion of radon, and noted that there
was a wide range in the estimates, due mainly to differences and
uncertainties in the way radon is assumed to be absorbed across the
gastrointestinal tract. Therefore, the committee developed new
mathematical models of the diffusion of radon in the stomach and the
behavior of radon dissolved in blood and other tissues to calculate the
radiation dose absorbed by tissues following ingestion of radon
dissolved in water (NAS 1999b).
NAS determined that the stomach wall has the largest exposure (and
hence the largest risk of cancer) following oral exposure to radon in
water, but that
[[Page 59316]]
there is substantial uncertainty on the rate and extent of radon entry
into the wall of the stomach from the stomach contents. The ``base
case'' used by NAS assumed that diffusion of radon from the stomach
contents occurs through a surface mucus layer and a layer of non-
radiosensitive epithelial cells before coming into proximity with the
radiosensitive stem cells. Below this layer, diffusion into capillaries
was assumed to remove radon and reduce the concentration to zero. Based
on this model, the concentration of radon near the stem cells was about
30 percent of that in the stomach contents.
The distribution of absorbed radon to peripheral tissues was
estimated by NAS using a physiologically-based pharmacokinetic (PBPK)
model based on the blood flow model of Leggett and Williams (1995). The
committee's analysis considered that each radioactive decay product
formed from radon decay in the body exhibited its own behavior with
respect to tissues of deposition, retention, and routes of excretion
with the ICRP's age-specific biokinetic models The computational method
used by the NAS Radon in Drinking Water committee to calculate the age-
and gender-averaged cancer death risk from lifetime ingestion of radon
is described in EPA's Federal Guidance Report 13 (USEPA 1998d).
Results: Ingestion Unit Risk
The NAS Radon in Drinking Water committee estimated that an age-
and gender-averaged cancer death risk from lifetime ingestion of radon
dissolved in drinking water at a concentration of 1 Bq/L probably lies
between 3.8 x 10-7 and 4.4 x 10-6, with 1.9
x 10-6 as the best central value. This is equivalent to a
lifetime risk of 7.0 x 10-8 per pCi/L, with a credible
range of 1.4 x 10-8 to 1.6 x 10-7 per pCi/L.
This uncertainty range is based mainly on uncertainty in the estimated
dose to the stomach and in the epidemiologic data used to estimate the
risk (NAS 1999b), and does not include the uncertainty in exposure
factors such as average daily direct tap water ingestion rates or radon
loss before ingestion. The lifetime risk estimate of 7.0 x
10-8 per pCi/L corresponds to an ingestion risk coefficient
of 4.29 x 10-12 per pCi ingested.
Ingestion Risk to Children
NAS (1999b) performed an analysis to investigate the relative
contribution of radon ingestion at different ages to the total risk.
This analysis considered the age dependence of: radon consumption,
behavior of radon and its decay products in the body, organ size, and
risk. The results indicated that even though water intake rates are
lower in children than in adults, dose coefficients are higher in
children because of their smaller body size. In addition, the cancer
risk coefficient for ingested radon is greater for children than for
adults. Based on dose and stomach cancer risk models, NAS (1999b)
estimated that about 30% of lifetime ingestion risk was due to
exposures occurring during the first 10 years of life. However, the NAS
found no direct epidemiological evidence to suggest that any sub-
population is at increased risk from ingestion of radon. In addition,
ingestion risk as a whole accounts for only 11% of total risk from
radon exposure from drinking water for the general population, with
inhalation accounting for the remaining 89%. The NAS did not identify
children, or any other groups except smokers, as being at significantly
higher overall risk from exposure to radon in drinking water.
(f) Summary of NAS Lifetime Unit Risk Estimates. Table XII.4
summarizes the lifetime average unit risk estimates derived by the NAS
Radon in Drinking Water committee.
Table XII.4.--Nas Radon in Drinking Water Committee Estimate of Lifetime Unit Risk Posed by Exposure to Radon in
Drinking Water
----------------------------------------------------------------------------------------------------------------
Gender-averaged lifetime unit risk
Exposure route Smoking status --------------------------------------------------
Risk per Bq/L in water Risk per pCi/L in water
----------------------------------------------------------------------------------------------------------------
Inhalation.......................... Ever................... 2.6 x 10-5 9.6 x 10-7
Never.................. 0.50 x 10-5 1.9 x 10-7
All.................... 1.6 x 10-5 5.9 x 10-7
Ingestion........................... All.................... 0.19 x 10-5 7.0 x 10-8
---------------------------------------------------------------------------
Total Risk (inhalation + All.................... 1.8 x 10-5 6.6 x 10-7
ingestion).
----------------------------------------------------------------------------------------------------------------
(g) Other Health Effects. The NAS Radon in Drinking Water committee
was asked to review teratogenic and reproductive risks from radon. The
committee concluded there is no scientific evidence of teratogenic and
reproductive risks associated with either inhalation or ingestion of
radon.
(h) Relative Magnitude of the Risk from Radon in Water. The NAS
Radon in Drinking Water committee concluded that radon in water
typically adds only a small increment to the indoor air concentration.
The committee estimated the cancer deaths per year due to radon in
indoor air (total), radon in outdoor air, radon progeny from waterborne
radon, and ingestion of radon in water are 18, 200, 720, 160, and 23,
respectively. However, the committee recognized that radon in water is
the largest source of cancer risk in drinking water compared to other
regulated chemicals in water.
D. Estimated Individual and Population Risks
Based on the findings and recommendations of the NAS Radon in
Drinking Water committee, EPA has performed a re-evaluation of the
risks posed by radon in water (USEPA 1999b). This assessment relied
upon the inhalation and ingestion unit risks derived by NAS (1999b),
and calculated risks to individuals and the population by combining the
unit risks derived by NAS with the latest available data on the
occurrence of radon in public water systems (USEPA 1999g).
In brief, the risk to a person from exposure to radon in water is
calculated by multiplying the concentration of radon in the water (pCi/
L) by the unit risk factor (risk per pCi/L) for the exposure pathway of
concern (ingestion, inhalation). The population risk (the total number
of fatal cancer cases per year in the United States due to radon
ingestion in water) is estimated by multiplying the average annual
individual risk (cases per person per year) by the total number of
people exposed. Data which EPA used to
[[Page 59317]]
calculate individual risks and population risks are summarized next.
Radon Concentration in Community Water Systems
The EPA has recently completed a detailed review and evaluation of
the latest available data on the occurrence of radon in community water
systems (USEPA 1999g; see Section XI). In brief, the concentration of
radon in drinking water from surface water sources is very low, and
exposures from surface water systems can generally be ignored. However,
radon does occur in most groundwater systems, with the concentration
values tending to be highest in areas where groundwater is in contact
with granite. In addition, radon concentrations tend to vary as a
function of the size of the water system, being somewhat higher in
small systems than in large systems (USEPA 1999g). Based on EPA's
analysis, the population-weighted average concentration of radon in
community ground water systems is estimated to be 213 pCi/L, with a
credible range of about 190 to 240 pCi/L (USEPA 1999g).
Total Exposed Population
Based on data available from the Safe Drinking Water Information
System (SDWIS), EPA estimates that 88.1 million people (about one-third
of the population of the United States) are served in their residence
by community water supply systems using ground water (USEPA 1998a).
Based on these data on radon occurrence and size of the exposed
population, EPA calculated the risks from water-borne radon to people
exposed at residences served by community groundwater systems. EPA also
calculated revised quantitative uncertainty analysis of the risk
estimates at residential locations, incorporating NAS estimates of the
uncertainty inherent in the unit risks for each pathway. In addition,
EPA performed screening level estimates of risk to people exposed to
water-borne radon in various types of non-residential setting. EPA's
findings are summarized next.
1. Risk Estimates for Ingestion of Radon in Drinking Water
Table XII.5 presents EPA's estimate of the mean individual risk
(fatal cancer cases per person per year) for the people who ingest
water from community ground water systems. This includes exposures that
occur both in the residence and in non-residential settings (the
workplace, restaurants, etc). The lower and upper bounds around the
best estimate were estimated using Monte Carlo simulation techniques
(USEPA 1999b).
Table XII.5.--Estimated Risk from Radon Ingestion at Residential and Non-residential Locations Served by
Community Water Systems
----------------------------------------------------------------------------------------------------------------
Parameter Lower bound Best estimate Upper bound
----------------------------------------------------------------------------------------------------------------
Mean Annual Individual Risk (cancer 3.2 x 10-8 2.0 x 10-7 4.3 x 10-7
deaths per person per year).
Population Risk (cancer deaths per 3 18 38
year).
----------------------------------------------------------------------------------------------------------------
2. Risk Estimates for Inhalation of Radon Progeny Derived From
Waterborne Radon
(a) Inhalation Exposure to Radon Progeny in the Residential
Environment. Table XII.6 presents the EPA's best estimate of the mean
individual risk and population risk of lung cancer fatality due to
inhalation of radon progeny derived from water-borne radon at
residences served by community groundwater systems. Lower and upper
bounds on the individual and population risk estimates were derived
using Monte Carlo simulation techniques.
Table XII.6.--Estimated Risks from Inhalation of Water-Borne Radon Progeny in Residences Served by Community
Ground Water Supply Systems
----------------------------------------------------------------------------------------------------------------
Parameter Lower bound Best estimate Upper bound
----------------------------------------------------------------------------------------------------------------
Mean Annual Individual Risk (lung 7.9 x 10-7 1.7 x 10-6 3.0 x 10-6
cancer deaths per person per year).
Population Risk (lung cancer deaths 70 148 263
per year).
----------------------------------------------------------------------------------------------------------------
Of the total number of lung cancer deaths due to water-borne radon,
most (about 84 percent) are expected to occur in ever-smokers, with the
remainder (about 16 percent) occurring in never-smokers.
Analysis of Peak Exposures and Risks Due to Showering
Both NAS and EPA have paid special attention to the potential
hazards associated with high exposures to radon that may occur during
showering. High exposure occurs during showering because a large volume
of water is used, release of radon from shower water is nearly
complete, and the radon enters a fairly small room (the shower/
bathroom). However, both NAS (1999b) and USEPA (1993b, 1995) concluded
that the risk to humans from radon released during showering was likely
to be small. This is because the inhalation risk from radon is due
almost entirely to radon progeny and not to radon gas itself, and it
takes time (several hours) for the radon progeny to build up from the
decay of the radon gas released from the water. For example, in a
typical shower scenario (about 10 minutes), the level of progeny builds
up to only 2 to 4 percent of its maximum possible value. Thus,
showering is one of many indoor water uses that contribute to the
occurrence of radon in indoor air, but hazards from inhalation of radon
during showering are not of special concern.
(b) Inhalation Exposure to Radon Progeny in the Non-Residential
Environment. The results summarized to this point relate to exposures
which occur in homes. However, on average, people spend about 30
percent of their time at other locations. Surveys of human activity
patterns reveal that time outdoors or in cars accounts for about 13
percent of the time (USEPA 1996), and about 17 percent of the time, on
average across the entire population (including both workers and non-
workers), is spent in non-residential structures. Such non-residential
buildings are presumably all served with water, so exposure to radon
and radon progeny is expected to occur, at least in buildings served by
groundwater. Because data needed to quantify exposure at non-
residential locations are limited, EPA has performed only a screening
[[Page 59318]]
level evaluation to date. This evaluation may be revised in the future,
depending on the availability of more detailed and appropriate input
data.
As with exposures in the home, the largest source of exposure and
risk from water-borne radon in non-residential buildings is inhalation
of radon progeny. Limited data were found on measured transfer factors
in non-residential buildings, so values were estimated for several
different types of buildings based on available data on water use
rates, building size, and ventilation rate, based on the following
basic equation:
TF = (We)/(V)
Where:
W = Water use (L/person/day)
e = Use-weighted fractional release of radon from water to air
V = Building volume (L/person)
= Ventilation rate (air changes/day)
The resulting transfer factor values varied as a function of
building type, based on limited data, but the average across all
building types was about 1 x 10-4 (the same as for
residences). Very few data were located for the equilibrium factor in
non-residential buildings, so a value of 0.4 (the same as in a
residence) was assumed (USEPA 1999b).
Based on an estimated average transfer factor of 1 x
10-4 and assuming an average occupancy factor of 17 percent
at non-residential locations, the estimated lifetime and annual risks
of death from lung cancer due to exposure per unit concentration of
radon (1pCi/L) in water are 1.4 x 10-7 per pCi/L and 1.9
x 10-9 per pCi/L, respectively.
Assuming a mean radon concentration in water of 213 pCi/L, these
unit risks correspond to lifetime and annual individual risks of 3.1
x 10-5 and 4.1 x 10-7 lung cancer deaths per
person. Assuming the same population size of 88.1 million population
exposed to radon through community ground water supplies, EPA's best
estimate of the number of fatal cancer cases per year resulting from
the inhalation of radon progeny in non-residential environments is 36
lung cancer deaths per year (USEPA 1999b) (from the population of
individuals exposed in non-residential settings served by community
ground water supplies).
(c) Analysis of Risk Associated with Exposure at NTNC Locations. A
subset of the water systems serving non-residential populations are the
non-transient non-community (NTNC) systems. Statistics from SDWIS
indicate there are about 5.2 million individuals exposed at buildings
served by NTNC groundwater systems (USEPA 1999b).
Data on radon exposures at locations served by NTNC systems are
limited. However, data are available for water used and population size
at each of 40 strata of NTNC systems (USEPA 1998a). Assuming (a) the
exposure at NTNC locations is occupational in nature with about 8 hr/
day, 250 days/yr, and 25 years per lifetime for workers and 8 hr/day,
180 days/yr, and 12 years per lifetime for students, (b) the same
transfer factor (1 x 10-4) and equilibrium factor (0.4)
assumed for other non-residential buildings apply at NTNC locations,
and (c) the concentration of radon in water at NTNC locations is about
60 percent higher than in community water systems (mean concentration =
341 pCi/L) (see Section XI of this preamble), then the estimated
population-weighted average individual annual and lifetime lung cancer
risks are 2.6 x 10-7 and 2.0 x 10-5,
respectively.
3. Risk Estimates for Inhaling Radon Gas
NAS (1999b) did not derive a unit risk factor for inhalation of
radon gas, but provided in their report a set of annual effective doses
to tissues (liver, kidney, spleen, red bone marrow, bone surfaces,
other tissues) from continuous exposure to 1Bq/m3 of radon
in air. These doses to internal organs from the decay of radon gas
absorbed across the lung and transported to internal sites were based
on calculations by Jacobi and Eisfeld (1980). Based on these dose
estimates, EPA estimated a unit risk value using an approach similar to
that used by NAS to derive the unit risk for ingestion of radon gas in
water. The organ-specific doses reported by Jacobi and Eisfeld were
multiplied by the lifetime-average organ-specific and gender-specific
risk coefficients (risk of fatal cancer per rad) from Federal Guidance
Report No. 13 (USEPA 1998d). Based on an average transfer factor of 1
x 10-4, and assuming 70 percent occupancy, the estimated
annual average unit risk is 8.5 x 10-11 cancer deaths per
pCi/L in water. This corresponds to a lifetime average unit risk of 6.3
x 10-9 per pCi/L. This unit risk excludes the risk of lung
cancer from inhaled radon gas, since this risk is already included in
the unit risk from radon progeny. Based on the population-weighted
average radon concentration of 213 pCi/L, the lifetime average
individual risk is 1.35 x 10-6 cancer deaths per person,
and the average annual individual risk is 1.8 x 10-8
cancer deaths per person per year. Based on an exposed population of
88.1 million people, the annual population risk is about 1.6 cancer
deaths/year. The uncertainty range around this estimate, derived using
Monte Carlo simulation techniques, is about 1.0 to 2.7 cancer deaths
per year (USEPA 1999b).
4. Combined Fatal Cancer Risk
The best estimates of fatal cancer risks to residents from
ingesting radon in water, inhalation of waterborne progeny, and
inhalation of radon gas are presented in Table XII.7. As seen, EPA
estimates that an individual's combined fatal cancer risk from lifetime
residential exposure to drinking water containing 1 pCi/L of radon is
slightly less than 7 chances in 10 million (7 x 10-7), and
that the population risk is about 168 cancer deaths per year
(uncertainty range = 80 to 288 per year). Of this risk, most (88
percent) is due to inhalation of radon progeny, with 11 percent due to
ingestion of radon gas, and less than 1 percent due to inhalation of
radon gas.
Table XII.7.--Summary of Unit Risk, Individual Risk and Population Risk Estimates for Residential Exposure to
Radon in Community Groundwater Supplies
----------------------------------------------------------------------------------------------------------------
Annual
Lifetime unit risk (fatal Annual individual risk population
Exposure pathway cancer cases per person (fatal cancer cases per risk (fatal
per pCi/L) person per year) cancer cases
per year)
----------------------------------------------------------------------------------------------------------------
Radon Gas Ingestion....................... 7.0 x 10-8 2.0 x 10-7 18
Radon Progeny Inhalation.................. 5.9 x 10-7 1.7 x 10-6 148
[[Page 59319]]
Radon Gas Inhalation...................... 6.3 x 10-9 1.8 x 10-8 1.6
---------------------------------------------------------------------
Total (credible bounds)............... 6.7 x 10-7 (3.6 x 10-7 1.9 x 10-6 (0.9 x 10-6 168 (80-288)
- 9.7 x 10-7) - 3.3 x 10-6)
----------------------------------------------------------------------------------------------------------------
EPA believes that radon in community groundwater water systems also
contributes exposure and risk to people when they are outside the
residence (e.g., at school, work, etc.). Although data are limited, a
screening level estimate suggests that this type of exposure could be
associated with about 36 additional lung cancer deaths per year.
Request for Comment
EPA solicits public comments on its assessment of risk from radon
in drinking water. In particular, EPA requests comment and
recommendations on the best data sources and best approaches to use for
evaluating ingestion and inhalation exposures that occur for members of
the public (including both workers and non-workers) at non-residential
buildings (e.g. restaurants, churches, schools, offices, factories,
etc).
E. Assessment by National Academy of Sciences: Multimedia Approach to
Risk Reduction
The NAS report, ``Risk Assessment of Radon in Drinking Water,''
summarized several assessments of possible approaches relating
reduction of radon in indoor air from soil gas to reduction of radon in
drinking water. The NAS Report provided useful perspectives on
multimedia mitigation issues that EPA used in developing the proposed
criteria and guidance for multimedia mitigation programs. The NAS
Committee focused on how the multimedia approach might be applied at
the community level and defined a series of scenarios, assuming that
multimedia programs would be implemented by public water systems. The
report may provide useful perspectives of interest to public water
systems if their State does not develop an EPA-approved MMM program.
For most of the scenarios, the Committee chose primarily to focus
on how to compare the risks posed by radon in indoor air from soil gas
to the risks from radon in drinking water in a home in a local
community. They assessed the feasibility of different activities based
on costs, radon concentrations, different assumptions about risk
reduction actions that might be taken, and other factors.
Overall, the Committee suggested that reduction of indoor radon can
be an alternative and more effective means of reducing the overall risk
from radon. They went on to conclude that mitigation of airborne radon
to achieve equal or greater radon risk reduction ``makes good sense
from a public health perspective.'' They also noted that non-economic
issues, such as equity concerns, could factor into a community's
decision whether to undertake a multimedia mitigation program.
The Committee also discussed the role of various indoor air
mitigation program strategies, or ``mitigation measures'' as they are
described in SDWA. The Committee concluded that an education and
outreach program is important to the success of indoor radon risk
reduction programs, but would not in and of itself be sufficient to
claim that risk reduction took place. Based on an assessment of several
State indoor radon programs, they found that States with effective
programs had several factors in common in the implementation of their
programs. They concluded that the effectiveness of these State programs
were the result of: (1) Promoting wide-spread testing of homes, (2)
conducting radon awareness campaigns, (3) providing public education on
mitigation, and (4) ensuring the availability of qualified contractors
to test and mitigate homes.
These views are consistent with the examples of indoor radon
activities that Congress set forth in the radon provision in SDWA on
which State Multimedia Mitigation programs may rely. These include
``public education, testing, training, technical assistance,
remediation grants and loans and incentive programs, or other
regulatory or non-regulatory measures.'' These measures also represent
many of the same strategies that are integral to the current national
and State radon programs, as well as those outlined in the 1988 Indoor
Radon Abatement Act, sections 304 to 307 (15 U.S.C. 2664-2667).
EPA recognizes, as does the National Academy of Sciences, that
these activities and strategies are important to achieving public
awareness and action to reduce radon, but that these actions are not in
and of themselves actual risk reduction. Therefore, EPA has determined
that State MMM plans will need to set and track actual risk reduction
goals. However, the criteria and guidance for States to use in
designing MMM program plans provides extensive flexibility in choosing
strategies that reflect the needs of individual States.
The Committee discussed the effectiveness of various indoor radon
control technologies and recommended that active sub-slab
depressurization techniques are most effective for controlling radon in
the mitigation of elevated radon levels in existing buildings and in
the prevention of elevated levels in new buildings. (Active systems
rely on mechanically-driven techniques (powered fans) to create a
pressure gradient between the soil and building interior and thus,
prevent radon entry.) The Committee expressed concern over the adequacy
of the scientific basis for ensuring that such methods can be used
reliably as a consistent outcome of normal design and construction
methods. The Committee also noted the limited amount of data available
to quantify the reduction in indoor radon levels expected when such
techniques were used.
The Committee found that much of the comparative data available on
the impact of the passive radon-resistant new construction features is
confined to the impact of the passive thermal stack on radon levels and
not on the other features of the passive radon-resistant new
construction system, such as eliminating leakage paths, sealing utility
penetrations, and prescribing the extent and quality of aggregate
beneath the
[[Page 59320]]
foundation. The Committee found that the passive stack alone yielded
reductions in radon levels as great as 90%, that reductions in radon
levels of about 40% are more typical, and that the effect of the
passive stack may be considerably less in slab-on-grade houses that in
houses with basements. However, the Committee also stated that the
other features in the passive radon-resistant new construction system
contribute to reducing radon levels. EPA notes that there are
substantial difficulties in gathering good comparative data on these
other features because of the significant variability of radon
potential across building sites, even within a small area. In addition
it is impractical to test the same house with and without radon
resistant features. However, based on the Committee's discussion of the
contributions of these other features to reducing radon levels, it is
reasonable to expect that passive systems as a whole achieve greater
reductions in radon than the passive stack alone.
EPA agrees with the Committee's perspective that active radon-
reduction systems, while slightly more expensive, assure the greatest
risk reduction in not only the mitigation of existing homes, but also
in the construction of new homes. EPA also agrees with the Committee's
perspective that more data on passive new construction systems would
allow for more precise estimation of average expected reductions in
radon levels in new homes from application of passive radon-resistant
new construction techniques. However, EPA believes there is sufficient
data and application experience to have a reasonable assurance that the
passive techniques when used in new homes reduce indoor radon levels by
about 50% on average. Further, these techniques have been adopted by
the home construction industry into national model building codes and
by many State and local jurisdictions into their building codes. EPA
recommends that new homes built with passive radon-resistant new
construction features be tested after occupancy and if elevated levels
still exist, the passive systems be converted to active ones. For these
reasons, EPA believes it is appropriate to consider passive radon-
resistant new construction techniques for new homes as one means of
achieving risk reduction through new construction in multimedia
mitigation programs.
Economics and Impacts Analysis
XIII. What Is the EPA's Estimate of National Economic Impacts and
Benefits?
A. Safe Drinking Water Act (SDWA) Requirements for the HRRCA
Section 1412(b)(13)(C) of the SDWA, as amended, requires EPA to
prepare a Health Risk Reduction and Cost Analysis (HRRCA) to be used to
support the development of the radon NPDWR. EPA was to publish the
HRRCA for public comment and respond to significant comments in this
preamble. EPA published the HRRCA in the Federal Register on February
26, 1999 (64 FR 9559). Responses to significant comments on the HRRCA
are provided in Section XIII.H.
The HRRCA addresses the requirements established in Section
1412(b)(3)(C) of the amended SDWA, namely: (1) Quantifiable and non-
quantifiable health risk reduction benefits for which there is a
factual basis in the rulemaking record to conclude that such benefits
are likely to occur as the result of treatment to comply with each
level; (2) quantifiable and non-quantifiable health risk reduction
benefits for which there is a factual basis in the rulemaking record to
conclude that such benefits are likely to occur from reductions in co-
occurring contaminants that may be attributed solely to compliance with
the MCL, excluding benefits resulting from compliance with other
proposed or promulgated regulations; (3) quantifiable and non-
quantifiable costs for which there is a factual basis in the rulemaking
record to conclude that such costs are likely to occur solely as a
result of compliance with the MCL, including monitoring, treatment, and
other costs, and excluding costs resulting from compliance with other
proposed or promulgated regulations; (4) the incremental costs and
benefits associated with each alternative MCL considered; (5) the
effects of the contaminant on the general population and on groups
within the general population, such as infants, children, pregnant
women, the elderly, individuals with a history of serious illness, or
other subpopulations that are identified as likely to be at greater
risk of adverse health effects due to exposure to contaminants in
drinking water than the general population; (6) any increased health
risk that may occur as the result of compliance, including risks
associated with co-occurring contaminants; and (7) other relevant
factors, including the quality and extent of the information, the
uncertainties in the analysis, and factors with respect to the degree
and nature of the risk.
The HRRCA discusses the costs and benefits associated with a
variety of radon levels. Summary tables and figures are presented that
characterize aggregate costs and benefits, impacts on affected
entities, and tradeoffs between risk reduction and compliance costs.
The HRRCA serves as a foundation for the Regulatory Impact Analysis
(RIA) for this proposed rule.
B. Regulatory Impact Analysis and Revised Health Risk Reduction and
Cost Analysis (HRRCA) for Radon
Under Executive Order 12866, Regulatory Planning and Review, EPA
must estimate the costs and benefits of the proposed radon rule in a
Regulatory Impact Analysis (RIA) and submit the analysis to the Office
of Management and Budget (OMB) in conjunction with the proposed rule.
To comply with the requirements of E.O. 12866, EPA has prepared an RIA,
a copy of which is available in the public docket for this proposed
rulemaking. The revised HRRCA is now included as part of the RIA (USEPA
1999f). This section provides a summary of the information from the RIA
for the proposed radon rule.
1. Background: Radon Health Risks, Occurrence, and Regulatory History
Radon is a naturally occurring volatile gas formed from the normal
radioactive decay of uranium. It is colorless, odorless, tasteless,
chemically inert, and radioactive. Uranium is present in small amounts
in most rocks and soil, where it decays to other products including
radium, then to radon. Some of the radon moves through air or water-
filled pores in the soil to the soil surface and enters the air, and
can enter buildings through cracks and other holes in the foundation.
Some radon remains below the surface and dissolves in ground water
(water that collects and flows under the ground's surface). Due to
their very long half-life (the time required for half of a given amount
of a radionuclide to decay), uranium and radium persist in rock and
soil.
Exposure to radon and its progeny is believed to be associated with
increased risks of several kinds of cancer. When radon or its progeny
are inhaled, lung cancer accounts for most of the total incremental
cancer risk. Ingestion of radon in water is suspected of being
associated with increased risk of tumors of several internal organs,
primarily the stomach. As required by the SDWA, as amended, EPA
arranged for the National Academy of Sciences (NAS) to assess the
health risks of radon in drinking
[[Page 59321]]
water. The NAS released the pre-publication draft of the ``Report on
the Risks of Radon in Drinking Water,'' (NAS Report) in September 1998
and published the Report in July 1999 (NAS 1999b). The analysis in this
RIA uses information from the 1999 NAS Report (see Section XII.C of
this preamble). The NAS Report represents a comprehensive assessment of
scientific data gathered to date on radon in drinking water. The
report, in general, confirms earlier EPA scientific conclusions and
analyses of radon in drinking water.
NAS estimated individual lifetime unit fatal cancer risks
associated with exposure to radon from domestic water use for ingestion
and inhalation pathways (Table XIII.1). The results show that
inhalation of radon progeny accounts for most (approximately 88
percent) of the individual risk associated with domestic water use,
with almost all of the remainder (11 percent) resulting from directly
ingesting radon in drinking water. Inhalation of radon progeny is
associated primarily with increased risk of lung cancer, while
ingestion exposure is associated primarily with elevated risk of
stomach cancer.
Table XIII.1.--Estimated Radon Unit Lifetime Fatal Cancer Risks in
Community Water Systems
------------------------------------------------------------------------
Proportion
Cancer unit of total
Exposure pathway risk per pCi/L risk
in water (percent)
------------------------------------------------------------------------
Inhalation of radon progeny \1\........... 5.9 x 10-7 88
Ingestion of radon \1\.................... 7.0 x 10-8 11
Inhalation of radon gas \2\............... 6.3 x 10-9 1
-----------------------------
Total................................. 6.7 x 10-7 100
------------------------------------------------------------------------
\1\ Source: NAS 1998B.
\2\ Source: Calculated by EPA from radiation dosimetry data and risk
coefficients provided by NAS (NAS 1998B).
The NAS Report confirmed that indoor air contamination arising from
soil gas typically accounts for the bulk of total individual risk due
to radon exposure. Usually, most radon gas enters indoor air by
diffusion from soils through basement walls or foundation cracks or
openings. Radon in domestic water generally contributes a small
proportion of the total radon in indoor air.
The NAS Report is one of the most important inputs used by EPA in
the RIA. EPA has used the NAS's assessment of the cancer risks from
radon in drinking water to estimate both the health risks posed by
existing levels of radon in drinking water and also the cancer deaths
prevented by reducing radon levels.
In updating key analyses and developing the framework for the cost-
benefit analysis presented in the RIA, EPA has consulted with a broad
range of stakeholders and technical experts. Participants in a series
of stakeholder meetings held in 1997, 1998, and 1999 included
representatives of public water systems, State drinking water and
indoor air programs, Tribal water utilities and governments,
environmental and public health groups, and other Federal agencies.
The RIA builds on several technical components, including estimates
of radon occurrence in drinking water, analytical methods for detecting
and measuring radon levels, and treatment technologies. Extensive
analyses of these issues were undertaken by the Agency in the course of
previous rulemaking efforts for radon and other radionuclides. Using
data provided by stakeholders, and from published literature, the EPA
has updated these technical analyses to take into account the best
currently available information and to respond to comments on the 1991
proposed NPDWR for radon.
The analysis presented in the RIA uses updated estimates of the
number of active public drinking water systems obtained from EPA's Safe
Drinking Water Information System (SDWIS). Treatment costs for the
removal of radon from drinking water have also been updated. The RIA
follows current EPA policies with regard to the methods and assumptions
used in cost and benefit assessment.
As part of the regulatory development process, EPA has updated and
refined its analysis of radon occurrence patterns in ground water
supplies in the United States (USEPA 1998l). This new analysis
incorporates information from the EPA's 1985 National Inorganic and
Radionuclides Survey (NIRS) of approximately 1000 community ground
water systems throughout the United States, along with supplemental
data provided by the States, water utilities, and academic research.
The new study also addressed a number of issues raised by public
comments in the previous occurrence analysis that accompanied the 1991
proposed NPDWR, including characterization of regional and temporal
variability in radon levels, and the impact of sampling point for
monitoring compliance.
In general, radon levels in ground water in the United States have
been found to be the highest in New England and the Appalachian uplands
of the Middle Atlantic and Southeastern States. There are also isolated
areas in the Rocky Mountains, California, Texas, and the upper Midwest
where radon levels in ground water tend to be higher than the United
States average. The lowest ground water radon levels tend to be found
in the Mississippi Valley, lower Midwest, and Plains States. When
comparing radon levels in ground water to radon levels in indoor air at
the States level, the distributions of radon concentrations in indoor
air do not always mirror distributions of radon in ground water.
2. Consideration of Regulatory Alternatives
(a) Regulatory Approaches. The RIA evaluates MCL options for radon
in ground water supplies of 100, 300, 500, 700, 1000, 2000, and 4000
pCi/L. As Table VII.1 in Section VII of the preamble illustrates, the
costs and benefits increase as the radon level decreases and the
benefit-cost ratios are very similar at each level. The RIA also
presents information on the costs and benefits of implementing
multimedia mitigation (MMM) programs. The scenarios evaluated are
described in detail in Sections 9 and 10 of the RIA (USEPA 1999f).
Based on the analysis shown in the report, the selected regulatory
alternative discussed next has a significant multimedia mitigation
component. For more information on this analysis, please refer to the
RIA.
(b) Selected Regulatory Alternatives. A CWS must monitor for radon
in drinking water in accordance with the regulations, as described in
Section VIII of this preamble, and report their results to the State.
If the State determines that
[[Page 59322]]
the system is in compliance with the MCL of 300 pCi/L, the CWS does not
need to implement a MMM program (in the absence of a State program),
but must continue to monitor as required.
As discussed in Section VI, EPA anticipates that most States will
choose to develop a State-wide MMM program as the most cost-effective
approach to radon risk reduction. In this case, all CWSs within the
State may comply with the AMCL of 4000 pCi/L. Thus, EPA expects the
vast majority of CWSs will be subject only to the AMCL. In those
instances where the State does not adopt this approach, the proposed
regulation provides the following requirements:
(i) Requirements for Small Systems Serving 10,000 People or Less.
The EPA is proposing that small CWSs serving 10,000 people or less must
comply with the AMCL, and implement a MMM program (if there is no state
MMM program). This is the cut-off level specified by Congress in the
1996 Amendments to the Safe Drinking Water Act for small system
flexibility provisions. Because this definition does not correspond to
the definitions of ``small'' for small businesses, governments, and
non-profit organizations previously established under the RFA, EPA
requested comment on an alternative definition of ``small entity'' in
the preamble to the proposed Consumer Confidence Report (CCR)
regulation (63 FR 7620, February 13, 1998). Comments showed that
stakeholders support the proposed alternative definition. EPA also
consulted with the SBA Office of Advocacy on the definition as it
relates to small business analysis. In the preamble to the final CCR
regulation (63 FR 4511, August 19, 1998), EPA stated its intent to
establish this alternative definition for regulatory flexibility
assessments under the RFA for all drinking water regulations and has
thus used it for this radon in drinking water rulemaking. Further
information supporting this certification is available in the public
docket for this rule.
EPA's regulation expectation for small CWSs is the MMM and AMCL
because this approach is a much more cost-effective way to reduce radon
risk than compliance with the MCL. (While EPA believes that the MMM
approach is preferable for small systems in a non-MMM State, they may,
at their discretion, choose the option of meeting the MCL of 300 pCi/L
instead of developing a local MMM program). The CWSs will be required
to submit MMM program plans to their State for approval. (See Sections
VI.A and F for further discussion of this approach).
SDWA Section 1412(b)(13)(E) directs EPA to take into account the
costs and benefits of programs to reduce radon in indoor air when
setting the MCL. In this regard, the Agency expects that implementation
of a MMM program and CWS compliance with 4000 pCi/L will provide
greater risk reduction for indoor radon at costs more proportionate to
the benefits and commensurate with the resources of small CWSs. It is
EPA's intent to minimize economic impacts on a significant number of
small CWSs, while providing increased public health protection by
emphasizing the more cost-effective multimedia approach for radon risk
reduction.
(ii) Requirements for Large Systems Serving More Than 10,000
People. The proposal requires large community water systems, those
serving populations greater than 10,000, to comply with the MCL of 300
pCi/L unless the State develops a State-wide MMM program, or the CWS
develops and implements a MMM program meeting the four regulatory
requirements, in which case large systems may comply with the AMCL of
4,000pCi/L. CWSs developing their own MMM plans will be required to
submit these plans to their State for approval.
(c) Background on the Selection of the MCL and AMCL. For a
description of EPA's process in selecting the MCL and AMCL, see Section
VII.D of today's preamble.
C. Baseline Analysis
Data and assumptions used in establishing baselines for the
comparison of costs and benefits are presented in the next section.
While the rule as proposed does not require 100 percent compliance with
an MCL, an analysis of these full compliance scenarios are required by
the SDWA, as amended, and were an important feature in the development
of the NPDWR for radon.
1. Industry Profile
Radon is found at appreciable levels only in systems that obtain
water from ground water sources. Thus, only ground water systems would
be affected by the proposed rule. The following discussion addresses
various characteristics of community ground water systems that were
used in the assessment of regulatory costs and benefits. Table XIII.2
shows the estimated number of community ground water systems in the
United States. This data originally came from EPA's Safe Drinking Water
Information System (SDWIS) and are summarized in EPA's Drinking Water
Baseline Handbook (USEPA, 1999c). EPA estimates that there were 43,908
community ground water systems active in December 1997 when the SDWIS
data were evaluated. Approximately 96.5 percent of the systems serve
fewer than 10,000 customers, and thus fit EPA's definition of a
``small'' system (see 63 FR 44512 at 44524-44525, August 19, 1998).
Privately-owned systems comprise the bulk of the smaller size
categories, whereas most larger systems are publicly owned.
Table XIII.2.--Number of Community Ground Water Systems in the United States \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
System size category
Primary source/ownership ------------------------------------------------------------------------------------------------------------------------------------
25-100 101-500 501-1,000 1,001-3,301 3,301-10,000 10,001-50,000 50,001-100,000 100,001-1,000,000 >1,000,000 Total
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total...................................................... 14,232 15,070 4,739 5,726 2,489 1,282 139 70 2 43,908
Public..................................................... 1,202 4,104 2,574 3,792 1,916 997 113 52 2 14,764
Private.................................................... 12,361 9,776 1,705 1,531 459 243 24 14 0 26,252
Purchased-Public........................................... 114 427 265 272 84 36 1 4 0 1,203
Purchased-Private.......................................... 171 347 101 79 13 3 1 0 0 718
Other...................................................... 384 416 94 52 17 3 0 0 0 971
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Source: USEPA 1999c.
In addition to the number of affected systems, the total number of
sources (wells) is an important determinant of potential radon
mitigation costs. Larger systems tend to have larger numbers of sources
than small ones, and it has been
[[Page 59323]]
conservatively assumed in the mitigation cost analysis that each source
out of compliance with the MCL or AMCL would need to install control
equipment.
Table XIII.3 summarizes the estimated number of wells per ground
water system. Both the number of wells and the variability in the
number of wells increases with the number of customers served. These
characteristics of community ground water sources are included in the
mitigation cost analysis discussed in Section 7 of the RIA (USEPA
1999f).
2. Baseline Assumptions
In addition to the characteristics of the ground water suppliers,
other important ``baseline'' assumptions were made that affect the
estimates of potential costs and benefits of radon mitigation. Two of
the most important assumptions relate to the distribution of radon in
ground water sources and the technologies that are currently in place
for ground water systems to control radon and other pollutants.
As noted in Section 3 of the RIA (USEPA 1999f), EPA has recently
completed an analysis of the occurrence patterns of radon in
groundwater supplies in the United States (USEPA 1999g). This analysis
used the NIRS and other data sources to estimate national distributions
of groundwater radon levels in community systems of various sizes. The
results of that analysis are summarized in Table XIII.4. These
distributions are used to calculate baseline individual and population
risks, and to predict the proportions of systems of various sizes that
will require radon mitigation.
Table XIII.3.--Estimated Average Number of Wells Per Groundwater System \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
System size category
-----------------------------------------------------------------------------------------------------------------------
25-100 101-500 501-1,000 1001-3,301 3,301-10,000 10,001-50,000 50,001-100,000 100,001-1,000,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average Number of Wells 1.5 (0.2) 2.0 (0.2) 2.3 (0.2) 3.1 (0.3) 4.6 (1.1) 9.8 (1.8) 16.1 (2.2) 49.9 (12.7)
(Confidence Interval)..........
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Source: USEPA 1999c.
Table XIII.4.--Distribution of Radon Levels in U.S. Groundwater Sources
----------------------------------------------------------------------------------------------------------------
Population served
Statistic ---------------------------------------------------------------------
25-100 101-500 501-3,300 3,301-10,000 >10,000
----------------------------------------------------------------------------------------------------------------
Geometric Mean, pCi/L..................... 312 259 122 124 132
Geometric Standard Deviation, pCi/L....... 3.04 3.31 3.22 2.29 2.31
Arithmetic Mean........................... 578 528 240 175 187
----------------------------------------------------------------------------------------------------------------
The costs of radon mitigation are affected to some extent by the
treatment technologies that are currently in place to mitigate radon
and other pollutants, and by the existence of pre- and post-treatment
technologies that affect the costs of mitigation. EPA has conducted an
extensive analysis of water treatment technologies currently in use by
groundwater systems. Table XIII.5 shows the proportions of ground water
systems with specific technologies already in place, broken down by
system size (population served). Many ground water systems currently
employ disinfection, aeration, or iron/manganese removal technologies.
This distribution of pre-existing technologies serves as the baseline
against which water treatment costs are measured. For example, costs of
disinfection are attributed to the radon rule only for the estimated
proportion of systems that would have to install disinfection as a
post-treatment because they do not already disinfect. The cost analysis
assumes that any system affected by the rule will continue to employ
pre-existing radon treatment technology and pre- and post-treatment
technologies in their efforts to comply with the rule. Where pre- or
post-treatment technologies are already in place it is assumed that
compliance with the radon rule will not require any upgrade or change
in the pre- or post-treatment technologies. Therefore, no incremental
cost is attributed to pre- or post-treatment technologies. This may
underestimate costs if pre- or post-treatment technologies need to be
changed (e.g., a need for additional chlorination after the
installation of packed tower aeration). The potential magnitude of this
cost underestimation is not known, but is likely to be a very small
fraction of total treatment costs.
Table XIII.5.--Estimated Proportions of Groundwater Systems With Water Treatment Technologies Already in Place (Percent) \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
System Size (Population Served)
-------------------------------------------------------------------------------------------------------------
Water treatment technologies in place 100,001
25-100 101-500 501-1,000 1,001-3,300 3,301-10,000 10,001-50,000 50,001-100,000 1,000,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fe/Mn removal & aeration & disinfection... 0.4 0.2 1.2 0.6 2.9 2.2 3.1 2
Fe/Mn removal & aeration.................. 0 0.1 0.2 0.1 0.4 0.1 0.4 0.1
Fe/Mn removal & disinfection.............. 2.1 5.1 8.3 3 7.8 7.4 9.7 6.8
Fe/Mn removal............................. 1.9 1.5 1.5 1 1.1 0.4 1.1 0.2
Aeration & disinfection only.............. 0.9 3.2 9.8 13.7 20.9 19.7 18.6 19.9
Aeration only............................. 0.8 1 1.8 2.9 2.9 1 2.1 0.6
Disinfection only......................... 49.6 68.2 65 65 56.3 66 58.3 68.3
[[Page 59324]]
None...................................... 44.3 20.7 12.2 13.7 7.7 3.2 6.7 2.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\. Source: EPA analysis of data from the Community Water System Survey (CWSS), 1997, and Safe Drinking Water Information System (SDWIS), 1998.
The treatment baseline assumptions shown in Table XIII.5 were used
in the initial analysis for the development of the NPDWR for radon.
These assumptions were used to establish the costs of 100 percent
compliance with an MCL. Another analysis, which portrays the costs of
the rule as recommended in this proposed rulemaking, is provided in the
results section of this summary and also in Section 9 of the RIA.
D. Benefits Analysis
11. Quantifiable and Non-Quantifiable Health Benefits
The quantifiable health benefits of reducing radon exposures in
drinking water are attributable to the reduced incidence of fatal and
non-fatal cancers, primarily of the lung and stomach. Table XIII.6
shows the health risk reductions (number of fatal and non-fatal cancers
avoided) and the residual health risk (number of remaining cancer
cases) at various radon in water levels.
Table XIII.6.--Residual Cancer Risk and Risk Reduction from Reducing Radon in Drinking Water
----------------------------------------------------------------------------------------------------------------
Risk Risk
Residual Residual reduction reduction
fatal cancer non-fatal (fatal (non-fatal
Radon Level (pCi/L in water) risk (cases cancer risk cancers cancers
per year) (cases per avoided per avoided per
year) year)\1\ year)\1\
----------------------------------------------------------------------------------------------------------------
(Baseline)............................................... 168 9.7 0 0
4,0002 \2\............................................... 165 9.5 2.9 0.2
2,000.................................................... 160 9.4 7.3 0.4
1,000.................................................... 150 8.8 17.8 1.1
700...................................................... 141 8.3 26.1 1.5
500...................................................... 130 7.6 37.6 2.2
300...................................................... 106 6.1 62.0 3.6
100...................................................... 46.8 2.8 120 7.0
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Risk reductions and residual risk estimates are slightly inconsistent due to rounding.
\2\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA provisions of Section 1412(b)(13).
Since preparing the prepublication edition of the NAS Report, the
NAS has reviewed and slightly revised their unit risk estimates. EPA
uses these updated unit risk estimates in calculating the baseline
risks, health risk reductions, and residual risks. Under baseline
assumptions (no control of radon exposure), approximately 168 fatal
cancers and 9.7 non-fatal cancers per year are associated with radon
exposures through CWSs. At a radon level of 4,000 pCi/L, approximately
2.9 fatal cancers and 0.2 non-fatal cancers per year are prevented. At
300 pCi/L, approximately 62.0 fatal cancers and 3.6 non-fatal cancers
are prevented each year.
The Agency has developed monetized estimates of the health benefits
associated with the risk reductions from radon exposures. The SDWA, as
amended, requires that a cost-benefit analysis be conducted for each
NPDWR, and places a high priority on better analysis to support
rulemaking. The Agency is interested in refining its approach to both
the cost and benefit analysis, and in particular recognizes that there
are different approaches to monetizing health benefits. In the past,
the Agency has presented benefits as cost per life saved, as in Table
XIII.7.
The costs of reducing radon to various levels, assuming 100 percent
compliance with an MCL, are summarized in Table XIII.7, which shows
that, as expected, aggregate radon mitigation costs increase with
decreasing radon levels. For CWSs, the costs per system do not vary
substantially across the different radon levels evaluated. This is
because the menu of mitigation technologies for systems with various
influent radon levels remains relatively constant and are not sensitive
to percent removal.
Table XIII.7.--Estimated Annualized National Costs of Reducing Radon Exposures
[$Million, 1997]
----------------------------------------------------------------------------------------------------------------
Central
tendency Total Total cost per
Radon level (pCi/L) estimate of annualized fatal cancer
annualized national costs case avoided
costs \2\ \3\
----------------------------------------------------------------------------------------------------------------
4000 \1\........................................................ 34.5 43.1 14.9
2000............................................................ 61.1 69.7 9.5
[[Page 59325]]
1000............................................................ 121.9 130.5 7.3
700............................................................. 176.8 185.4 7.1
500............................................................. 248.8 257.4 6.8
300............................................................. 399.1 407.6 6.6
100............................................................. 807.6 816.2 6.8
----------------------------------------------------------------------------------------------------------------
\1\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
\2\ Costs include treatment, monitoring, and O&M costs only.
\3\ Costs include treatment, monitoring, O&M, recordkeeping, reporting, and state costs for administration of
water programs.
An alternative approach presented here for consideration as one
measure of potential benefits is the monetary value of a statistical
life (VSL) applied to each fatal cancer avoided. Since this approach is
relatively new to the development of NPDWRs, EPA is interested in
comments on these alternative approaches to valuing benefits, and will
have to weigh the value of these approaches for future use.
Estimating the VSL involves inferring individuals' implicit
tradeoffs between small changes in mortality risk and monetary
compensation. In the HRRCA, a central tendency estimate of $5.8 million
(1997$) is used in the monetary benefits calculations. This figure is
determined from the VSL estimates in 26 studies reviewed in EPA's
recent draft guidance on benefits assessment (USEPA 1998e), which is
currently under review by the Agency's Science Advisory Board (SAB) and
the Office of Management and Budget (OMB).
It is important to recognize the limitations of existing VSL
estimates and to consider whether factors such as differences in the
demographic characteristics of the populations and differences in the
nature of the risks being valued have a significant impact on the value
of mortality risk reduction benefits. Also, medical care or lost-time
costs are not separately included in the benefits estimate for fatal
cancers, since it is assumed that these costs are captured in the VSL
for fatal cancers.
For non-fatal cancers, willingness to pay (WTP) data to avoid
chronic bronchitis is used as a surrogate to estimate the WTP to avoid
non-fatal lung and stomach cancers. The use of such WTP estimates is
supported in the SDWA, as amended, at Section 1412(b)(3)(C)(iii): ``The
Administrator may identify valid approaches for the measurement and
valuation of benefits under this subparagraph, including approaches to
identify consumer willingness to pay for reductions in health risks
from drinking water contaminants.''
A WTP central tendency estimate of $536,000 is used to monetize the
benefits of avoiding non-fatal cancers (Viscusi et al. 1991). The
combined fatal and non-fatal health benefits are summarized in Table
XIII.8. The annual health benefits range from $17.0 million for a radon
level of 4000 pCi/L to $702 million at 100 pCi/L.
Table XIII.8.--Estimated Monetized Health Benefits from Reducing Radon
in Drinking Water
------------------------------------------------------------------------
Monetized
health
benefits,
central
Radon level (pCi/L) tendency
(annualized,
$millions,
1997)\1\
------------------------------------------------------------------------
4,000 \2\............................................... 17.0
2,000................................................... 42.7
1,000................................................... 103
700..................................................... 152
500..................................................... 219
300..................................................... 362
100..................................................... 702
------------------------------------------------------------------------
Notes:
\1\ Includes contributions from fatal and non-fatal cancers, estimated
using central tendency estimates of the VSL of $5.8 million (1997$),
and a WTP to avoid non-fatal cancers of $536,000 (1997$).
\2\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on
SDWA provisions of Section 1412(b)(13).
Reductions in radon exposures might also be associated with non-
quantifiable benefits. EPA has identified several potential non-
quantifiable benefits associated with regulating radon in drinking
water. These benefits may include any customer peace of mind from
knowing drinking water has been treated for radon. In addition, if
chlorination is added to the process of treating radon via aeration,
arsenic pre-oxidation will be facilitated. Neither chlorination nor
aeration will remove arsenic, but chlorination will facilitate
conversion of Arsenic (III) to Arsenic (V). Arsenic (V) is a less
soluble form that can be better removed by arsenic removal
technologies. In terms of reducing radon exposures in indoor air, it
has also been suggested that provision of information to households on
the risks of radon in indoor air and available options to reduce
exposure may be a non-quantifiable benefit that can be attributed to
some components of a MMM program. Providing such information might
allow households to make more informed choices than they would have in
the absence of an MMM program about the need for risk reduction given
their specific circumstances and concerns. In the case of the proposed
radon rule, it is not likely that accounting for these non-quantifiable
benefits would significantly alter the overall assessment.
The benefits calculated for this proposal are assumed to begin to
accrue on the effective date of the rule and are based on a calculation
referred to as the ``value of a statistical life'' (VSL), currently
estimated at $5.8 million. The VSL is an average estimate derived from
a set of 26 studies estimating what people are willing to pay to avoid
the risk of premature mortality. Most of these studies examine
willingness to pay in the context of voluntary acceptance of higher
risks of immediate accidental death in the workplace in exchange for
higher wages. This value is sensitive to differences in population
characteristics and perception of risks being valued.
For the present rulemaking analysis, which evaluates reduction in
premature mortality due to carcinogen exposure, some commenters have
argued that the Agency should consider an assumed time lag or latency
period in these calculations. Latency refers to the difference between
the time of initial exposure to environmental carcinogens and the onset
of any resulting cancer. Use of such an approach might reduce
significantly the present value estimate.
[[Page 59326]]
The BEIR VI model and U.S. vital statistics, on which the estimate of
lung cancers avoided is based, imply a probability distribution of
latency periods between inhalation exposure to radon and increased
probability of cancer death. EPA is interested in receiving comments on
the extent to which the presentation of more detailed information on
the timing of cancer risk reductions would be useful in evaluating the
benefits of the proposed rule.
Latency is one of a number of adjustments or factors that are
related to an evaluation of potential benefits associated with this
rule, how those benefits are calculated, and when those economic
benefits occur. Other factors which may influence the estimate of
economic benefits associated with avoided cancer fatalities include (1)
A possible ``cancer premium'' (i.e., the additional value or sum that
people may be willing to pay to avoid the experiences of dread, pain
and suffering, and diminished quality of life associated with cancer-
related illness and ultimate fatality); (2) the willingness of people
to pay more over time to avoid mortality risk as their income rises;
(3) a possible premium for accepting involuntary risks as opposed to
voluntary assumed risks; (4) the greater risk aversion of the general
population compared to the workers in the wage-risk valuation studies;
(5) ``altruism'' or the willingness of people to pay more to reduce
risk in other sectors of the population; and (6) a consideration of
health status and life years remaining at the time of premature
mortality. Use of certain of these factors may significantly increase
the present value estimate. EPA therefore believes that adjustments
should be considered simultaneously. The Agency also believes that
there is currently neither a clear consensus among economists about how
to simultaneously analyze each of these adjustments nor is there
adequate empirical data to support definitive quantitative estimates
for all potentially significant adjustment factors. As a result, the
primary estimates of economic benefits presented in the analysis of
this rule rely on the unadjusted $5.8 million estimate. However, EPA
solicits comment on whether and how to conduct these potential
adjustments to economic benefits estimates together with any rationale
or supporting data commenters wish to offer. Because of the complexity
of these issues, EPA will ask the Science Advisory Board (SAB) to
conduct a review of these benefits transfer issues associated with
economic valuation of adjustments in mortality risks. In its analysis
of the final rule, EPA will attempt to develop and present an analysis
and estimate of the latency structure and associated benefits transfer
issues outlined previously consistent with the recommendations of the
SAB and subject to resolution of any technical limitations of the data
and models.
E. Cost Analysis
1. Total National Costs of Compliance with MCL Options
Table XIII.9 summarizes the estimates of total national costs of
compliance with the range of potential MCLs considered. The table is
divided into two major groupings; the first grouping displays the
estimated costs to systems and the second grouping displays the
estimated costs to States. State costs, presented in Table XIII.9, were
developed as part of the analyses to comply with the Unfunded Mandates
Reform Act (UMRA) and also the Paperwork Reduction Act (PRA).
Additional information on State costs is provided in Section 8 of the
RIA and also in Section VIII of this preamble.
Table XIII.9.--Summary of Estimated Costs Under the Proposed Radon Rule Assuming 100% Compliance With an MCL of
300 pCi/L
[$ Millions] \1\
----------------------------------------------------------------------------------------------------------------
10 percent
3 percent cost 7 percent cost cost of
of capital of capital capital
----------------------------------------------------------------------------------------------------------------
Costs to Water Systems
----------------------------------------------------------------------------------------------------------------
Total Capital Costs (20 years, undiscounted).............. 2,463 2,463 2,463
----------------------------------------------------------------------------------------------------------------
Annual Costs
----------------------------------------------------------------------------------------------------------------
Annualized Capital.............................................. 165.6 232.5 289.4
Annual O&M...................................................... 152.4 152.4 152.4
-----------------------------------------------
Total Annual Treatment.................................... 318.0 385.0 441.8
-----------------------------------------------
Monitoring Costs................................................ 14.1 14.1 14.1
Recordkeeping and Reporting Costs \2\........................... 6.1 6.1 6.1
-----------------------------------------------
Total Annual Costs to Water Systems \3\................... 338.2 405.1 461.6
----------------------------------------------------------------------------------------------------------------
Costs to States
----------------------------------------------------------------------------------------------------------------
Administration of Water Programs................................ 2.5 2.5 2.5
-----------------------------------------------
Total Annual State Costs.................................. 2.5 2.5 2.5
Total Annual Costs of Compliance \4\...................... 340.6 407.6 464.4
----------------------------------------------------------------------------------------------------------------
1. Assumes no MMM program implementation costs (e.g., all systems comply with 300 pCi/L).
2. Figure represents average annual burden over 20 years.
3. Costs include treatment, monitoring, O&M, recordkeeping, and reporting costs to water systems.
4. Totals have been rounded. Costs include treatment, monitoring, O&M, recordkeeping, reporting, and state
costs for administration of water programs.
[[Page 59327]]
2. Quantifiable and Non-quantifiable Costs
The capital and operating and maintenance (O&M) costs of mitigating
radon in Community Water Systems (CWSs) were estimated for each of the
radon levels evaluated. The costs of reducing radon in community ground
water to specific target levels were calculated using the cost curves
discussed in Section 7.5 and the matrix of treatment options presented
in Section 7.6 of the RIA. For each radon level and system size
stratum, the number of systems that need to reduce radon levels by up
to 50 percent, 80 percent and 99 percent were calculated. Then, the
cost curves for the distributions of technologies dictated by the
treatment matrix were applied to the appropriate proportions of the
systems. Capital and O&M costs were then calculated for each system,
based on typical estimated design and average flow rates. These flow
rates were calculated on spreadsheets using equations from EPA's
Baseline Handbook (USEPA 1999e). The equations and parameter values
relating system size to flow rates are presented in Appendix C of the
RIA. The technologies addressed in the cost estimation included a
number of aeration and granular activated carbon (GAC) technologies
described in Section 7.2 of the RIA, as well as storage,
regionalization, and disinfection as a post-treatment. To estimate
costs, water systems were assumed, with a few exceptions to simulate
site-specific problems, to select the technology that could reduce
radon to the selected target level at the lowest cost. CWSs were also
assumed to treat separately at every source from which water was
obtained and delivered into the distribution system.
EPA has attempted to note potential non-quantifiable benefits when
the Agency believes they might occur, as in the case of peace-of-mind
benefits from radon reduction. The Agency recognizes that there may
also be non-quantifiable disbenefits, such as anxiety on the part of
those near aeration plants or those who find out that their radon
levels are high. It is not possible to determine whether the net
results of such psychological effects would be positive or negative.
The inclusion of non-quantifiable benefits and costs in this analysis
are not likely to alter the overall results of the benefit-cost
analysis for the proposed radon rule.
F. Economic Impact Analysis
A summary analysis of the impacts on small entities is shown in
Section XIV.B of this preamble (Regulatory Flexibility Act). An
analysis of the impacts on State, local, and tribal governments is
shown in Section XIV.C (Unfunded Mandates Reform Act). For information
on how this proposed rulemaking may impact Indian tribal governments,
see Section XIV.I of today's preamble. Information on the types of
information that States will be required to collect, as well as EPA's
estimate of the burden and reporting requirements for this proposed
rulemaking, is shown in Section XIV.D (Paperwork Reduction Act). EPA's
assessment of the impacts that this proposed rulemaking may have on
low-income and minority populations, as well as any potential concerns
regarding children's health, are shown in Section XIV.F (Environmental
Justice) and Section XIV.G (Protection of Children from Environmental
Health Risks and Safety Risks) of today's preamble.
G. Weighing the Benefits and Costs
1. Incremental Costs and Benefits of Radon Removal
Table XIII.10.--Estimates of the Annual Incremental Risk Reduction, Costs, and Benefits of Reducing Radon in Drinking Water Assuming 100% Compliance
With an MCL
[$ Millions 1997]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Radon Level, pCi/L
------------------------------------------------------------------------------------------
4000 \1\ 2000 1000 700 500 300 100
--------------------------------------------------------------------------------------------------------------------------------------------------------
Incremental Risk Reduction, Fatal Cancers Avoided Per Year... 2.9 4.4 10.5 8.4 11.5 24.4 58.4
Incremental Risk Reduction, Non-Fatal Cancers Avoided Per 0.2 0.3 0.6 0.4 0.8 1.3 3.5
Year........................................................
Annual Incremental Monetized Benefits, $ Million Per Year.... 17.0 25.7 61.0 48.7 67.1 142 341
Annual Incremental Radon Mitigation Costs, $ Million Per Year 34.5 26.6 60.8 54.9 72.0 150.3 408.5
\2\.........................................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
\2\ Costs include treatment, monitoring, and O&M costs only.
2. Impacts on Households
The cost impact of reducing radon in drinking water at the
household level was also assessed. As expected, costs per household
increase as system size decreases as shown in Table XIII.11.
Table XIII.11.--Annual Costs per Household for Community Water Systems to Treat to Various Radon Levels \1\
[$, 1997]
----------------------------------------------------------------------------------------------------------------
VVS (25- VVS (101- VS (501- S (3301- M (10,001-
Radon level (pCi/L) 100) 500) 3300) 10K) 100K) L (> 100K)
----------------------------------------------------------------------------------------------------------------
Households Served by PUBLIC Systems Above Radon Level by Population Served
----------------------------------------------------------------------------------------------------------------
4000 \2\........................ 256.5 91.0 22.7 14.3 6.2 4.5
2000............................ 259.0 92.8 23.5 14.9 7.1 5.2
1000............................ 262.5 94.8 24.6 15.4 8.6 6.4
700............................. 264.4 96.0 25.2 15.9 9.6 7.2
500............................. 266.3 97.1 25.9 16.4 10.6 8.1
[[Page 59328]]
300............................. 269.5 99.3 26.9 17.4 12.4 9.5
100............................. 278.8 107.1 29.1 20.1 16.2 12.8
----------------------------------------------------------------------------------------------------------------
Households Served by PRIVATE Systems Above Radon Level by Population Served
----------------------------------------------------------------------------------------------------------------
4000 \2\........................ 372.4 141.1 30.3 22.8 6.6 4.4
2000............................ 375.8 143.7 31.2 23.7 7.5 5.1
1000............................ 380.5 146.3 32.6 24.7 9.1 6.3
700............................. 383.1 147.8 33.4 25.4 10.1 7.1
500............................. 385.6 149.4 34.2 26.2 11.2 7.9
300............................. 389.8 152.2 35.5 27.7 13.1 9.4
100............................. 401.5 162.4 37.9 32.1 17.1 12.6
----------------------------------------------------------------------------------------------------------------
\1\ Reflects total household costs for systems to treat down to these levels. Because EPA expects that most
systems will comply with the AMCL/MCL, most systems will not incur these household costs.
\2\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
Costs to households are higher for households served by smaller
systems than larger systems for two reasons. First, smaller systems
serve far fewer households than larger systems and, consequently, each
household must bear a greater percentage share of the capital and O&M
costs. Second, smaller systems tend to have higher influent radon
concentrations that, on a per-capita or per-household basis, require
more expensive treatment methods (e.g., one that has an 85 percent
removal efficiency rather than 50 percent) to achieve the applicable
radon level.
To further evaluate the impacts of these household costs, the costs
per household were compared to median household income data for each
system-size category. The results of this calculation, presented in
Table XIII.12 for public and private systems, indicate a household's
likely share of average incremental costs in terms of the median
income. Actual costs for individual households will reflect higher or
lower income shares depending on whether they are above or below the
median household income (approximately $30,000 per year) and whether
the water system incurs above average or below average costs for
installing treatment. For all system sizes but very very small private
systems, average household costs as a percentage of median household
income are less than one percent for households served by either public
or private systems. Average impacts exceed one percent only for
households served by very very small private systems, which are
expected to face average impacts of 1.12 percent at the 4,000 pCi/l
level and 1.35 percent at the 300 pCi/l level and for households served
by very very small public systems at the 300 pCi/l level, whose average
costs barely exceed one percent. Similar to the average cost per
household results on which they are based, average household impacts
exhibit little variability across radon levels.
Table XIII.12.--Per Household Impact by Community Groundwater Systems as a Percentage of Median Household Income
[Percent]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average Impact to Households Served by Public Systems Average Impact to Households Served by Private Systems
Exceeding Radon Levels Exceeding Radon Levels
Radon level, pCi/L ------------------------------------------------------------------------------------------------------------------
VVS (25- VVS (101- VVS (25- VVS (101-
100) 500) VS S M L 100) 500) VS S M L
--------------------------------------------------------------------------------------------------------------------------------------------------------
4000 \1\............................. 0.86 0.30 0.13 0.06 0.03 0.02 1.12 0.35 0.16 0.07 0.04 0.02
2000................................. 0.92 0.36 0.12 0.05 0.02 0.01 1.19 0.42 0.16 0.09 0.02 0.01
1000................................. 0.96 0.38 0.13 0.05 0.02 0.01 1.24 0.44 0.16 0.09 0.03 0.01
700.................................. 0.98 0.38 0.13 0.06 0.03 0.02 1.27 0.45 0.17 0.09 0.03 0.01
500.................................. 1.00 0.39 0.13 0.06 0.03 0.02 1.30 0.45 0.17 0.09 0.03 0.01
300.................................. 1.05 0.40 0.14 0.06 0.03 0.02 1.35 0.47 0.18 0.10 0.04 0.02
100.................................. 1.17 0.44 0.15 0.07 0.05 0.03 1.51 0.51 0.19 0.12 0.05 0.02
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
3. Summary of Annual Costs and Benefits
Table XIII.13 reveals that at a radon level of 4000 pCi/L
(equivalent to the AMCL estimated in the NAS Report), annual costs of
100 percent compliance with an MCL are approximately twice the annual
monetized benefits. For radon levels of 1000 pCi/L to 300 pCi/L, the
central tendency estimates of annual costs are above the central
tendency estimates of the monetized benefits.
[[Page 59329]]
Table XIII.13.--Estimated National Annual Costs and Benefits \1\ of Reducing Radon Exposures Assuming 100%
Compliance with an MCL--Central Tendency Estimate
[$ Millions, 1997]
----------------------------------------------------------------------------------------------------------------
Annualized Total Annual
Radon level (pCi/L) treatment annualized Cost per fatal monetized
costs \2\ costs \3\ cancer avoided benefits
----------------------------------------------------------------------------------------------------------------
4000 \4\....................................... 34.5 43.1 14.9 17.0
2000........................................... 61.1 69.7 9.5 42.7
1000........................................... 121.9 130.5 7.3 103
700............................................ 176.8 185.4 7.1 152
500............................................ 248.8 257.4 6.8 219
300............................................ 399.1 407.6 6.6 362
100............................................ 807.6 816.2 6.8 702
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Benefits are calculated for stomach and lung cancer assuming that risk reduction begins immediately.
Estimates assume a $5.8 million value of a statistical life and willingness to pay of $536,000 for non-fatal
cancers.
\2\ Costs are annualized over twenty years using a discount rate of seven percent. Costs include treatment,
monitoring, and O&M costs.
\3\ Costs include treatment, monitoring, O&M, recordkeeping, reporting, and state costs for administration of
water programs.
\4\ 4000 pCi/L is equivalent to the AMCL estimated by the NAS based on SDWA requirements of Section 1412(b)(13).
Because the costs of compliance with an MCL for small systems
outweigh the benefits at each radon level (Table XIII.14), the MMM
option was recommended for small systems to alleviate some of the
financial burden to these systems and the households they serve and to
realize equivalent or greater benefits at much lower costs. The results
of the benefit-cost analyses for MMM implementation scenarios are shown
at the end of this section and also in Section 9 of the RIA.
Table XIII.14.-- Estimated Annual Costs and Benefits for 100% Compliance With an MCL by System Size
[$Millions, 1997]
--------------------------------------------------------------------------------------------------------------------------------------------------------
System size
Radon level (pCi/l) Parameter \1\ -----------------------------------------------------------------------------------
25-100 101-500 501-3300 3301-10,000 10,001-100K >100K
--------------------------------------------------------------------------------------------------------------------------------------------------------
4000................................. Benefits..................... 0.16 0.79 2.7 2.8 7.0 3.6
Costs........................ 7.8 14.3 6.3 2.9 2.7 0.5
2000................................. Benefits..................... 0.41 2.0 6.8 6.9 17.7 9.0
Costs........................ 13.2 22.7 11.6 5.7 6.3 1.6
1000................................. Benefits..................... 1.0 4.8 16.3 16.7 42.6 21.6
Costs........................ 23.1 36.5 24.7 13.4 18.9 5.3
700.................................. Benefits..................... 1.5 7.1 24.1 24.6 62.9 31.9
Costs........................ 30.6 46.5 36.3 21.1 32.8 9.5
500.................................. Benefits..................... 2.1 10.2 34.7 35.4 90.6 45.9
Costs........................ 39.4 57.9 50.8 32.0 53.0 15.6
300.................................. Benefits..................... 3.5 16.9 57.3 58.6 150 75.9
Costs........................ 55.6 79.3 78.8 56.1 99.3 26.9
100.................................. Benefits..................... 7.2 32.7 111 113 290 147
Costs........................ 93.4 134 147 122 238 73.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Costs do not include recordkeeping, reporting, or state costs for administration of water programs. Recordkeeping and reporting costs are estimated
at $6.1 million for all system sizes and State administration costs for water programs are estimated at $2.5 million.
Total costs to public and private water systems, by size, were also
evaluated in the RIA. Table XIII.15 presents the total annualized costs
for public and private systems by system size category for all radon
levels evaluated in the RIA. The costs are comparable for public and
private systems across system sizes for all options. This pattern may
be due in large part to the limited number of treatment options assumed
to be available to either public or private systems in mitigating
radon.
Table XIII.15.--Average Annual Cost Per System
[$Thousands, 1997]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Average costs to public systems exceeding radon levels Average costs to private systems exceeding radon levels
-------------------------------------------------------------------------------------------------------------------
Radon Level (pCi/l) VVS (25- VVS (101- VVS (25- VVS (101-
100) 500) VS S M L 100) 500) VS S M L
--------------------------------------------------------------------------------------------------------------------------------------------------------
4000................................ 8.2 12.4 18.5 49.3 82.3 484.9 7.6 10.1 15.6 43.7 72.1 468.5
2000................................ 8.3 12.6 19.1 51.3 94.1 560.7 7.7 10.3 16.2 45.5 82.4 541.8
1000................................ 8.4 12.9 26.6 60.1 115.9 693.4 7.8 10.5 16.8 47.3 100.2 670.2
700................................. 8.5 13.0 27.2 61.9 129.0 758.3 7.9 10.6 17.1 48.7 111.7 752.7
500................................. 8.5 13.2 27.8 63.7 143.2 847.8 7.9 10.7 17.5 50.3 123.9 841.6
300................................. 8.6 13.5 28.8 67.4 167.1 1000.4 8.0 10.9 18.1 53.3 144.7 992.9
100................................. 8.9 14.6 31.0 77.2 219.1 1345.3 8.2 11.6 19.1 61.8 189.6 1333.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 59330]]
Annual Per System Cost for those Systems Below Radon Levels: Monitoring Costs Only
--------------------------------------------------------------------------------------------------------------------------------------------------------
All................................. 0.3 0.3 0.4 0.6 1.1 2.6 0.3 0.3 0.4 0.6 1.1 2.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
4. Benefits From the Reduction of Co-Occurring Contaminants
The occurrence patterns of industrial pollutants are difficult to
clearly define at the national level relative to a naturally occurring
contaminant such as radon. Similarly, the Agency's re-evaluation of
radon occurrence has revealed that the geographic patterns of radon
occurrence are not significantly correlated with other naturally
occurring inorganic contaminants that may pose health risks. Thus, it
is not likely that a clear relationship exists between the need to
install radon treatment technologies and treatments to remove other
contaminants. On the other hand, technologies used to reduce radon
levels in drinking water have the potential to reduce concentrations of
other pollutants as well. Aeration technologies will also remove
volatile organic contaminants from contaminated ground water.
Similarly, granular activated carbon (GAC) treatment for radon removal
effectively reduces the concentrations of organic (both volatile and
nonvolatile) chemicals and some inorganic contaminants. Aeration also
tends to oxidize dissolved arsenic (a known carcinogen) to a less
soluble form that is more easily removed from water. The frequency and
extent that radon treatment would also reduce risks from other
contaminants has not been quantitatively evaluated.
5. Impacts on Sensitive Subpopulations
The SDWA, as amended, includes specific provisions in Section
1412(b)(3)(C)(i)(V) to assess the effects of the contaminant on the
general population and on groups within the general population such as
children, pregnant women, the elderly, individuals with a history of
serious illness, or other subpopulations that are identified as likely
to be at greater risk of adverse health effects due to exposure to
contaminants in drinking water than the general population. The NAS
Report concluded that there is insufficient scientific information to
permit separate cancer risk estimates for potential subpopulations such
as pregnant women, the elderly, children, and seriously ill persons.
The NAS Report did note, however, that according to the NAS model for
the cancer risk from ingested radon, which accounts for 11 percent of
the total fatal cancer risk from radon in drinking water, approximately
30 percent of the fatal lifetime cancer risk is attributed to exposure
between ages 0 to 10.
The NAS Report identified smokers as the only group that is more
susceptible to inhalation exposure to radon progeny (NAS 1999b).
Inhalation of cigarette smoke and radon progeny result in a greater
increased risk than if the two exposures act independently to induce
lung cancer. NAS estimates that ``ever smokers'' (more than 100
cigarettes over a lifetime) may be more than five times as sensitive to
radon progeny as ``never smokers'' (less than 100 cigarettes over a
lifetime). Using current smoking prevalence data, EPA's preliminary
estimate for the purposes of the HRRCA is that approximately 85 percent
of the cases of radon-induced cancer will occur among current and
former smokers. This population of current and former smokers, which
consists of 58 percent of the male and 42 percent of the female
population, will also experience the bulk of the risk reduction from
radon exposure reduction in drinking water supplies.
6. Risk Increases From Other Contaminants Associated With Radon
Exposure Reduction
As discussed in Section 7.2 of the RIA, the need to install radon
treatment technologies may require some systems that currently do not
disinfect to do so. Case studies (US EPA 1998j) of twenty-nine small to
medium water systems that installed treatment (24 aeration, 5 GAC) to
remove radon from drinking water revealed only two systems that
reported adding disinfection (both aeration) with radon treatment (the
other systems either had disinfection already in place or did not add
it). In practice, the tendency to add other disinfection with radon
treatment may be much more significant than these case studies
indicate. EPA also realizes that the addition of chlorination for
disinfection may result in risk-risk tradeoffs, since, for example, the
disinfection technology reduces potential for infectious disease risk,
but at the same time can result in increased exposures to disinfection
by-products (DBPs). This risk-risk trade-off is addressed by the
recently promulgated Disinfectants and Disinfection By-Products NPDWR
(63 FR 69390). This rule identified MCLs for the major DBPs, with which
all CWSs and NTNCWSs must comply. These MCLs set a risk ceiling from
DBPs that water systems adding disinfection in conjunction with
treatment for radon removal could face. The formation of DBPs
correlates with the concentration of organic precursor contaminants,
which tend to be much lower in ground water than in surface water. In
support of this statement, the American Water Works Association's
WATERSTATS survey (AWWA 1997) reports that more than 50% of the ground
water systems surveyed have average total organic carbon (TOC) raw
water levels less than 1 mg/L and more than 80% had TOC levels less
than 3 mg/L. On the other hand, WATERSTATS reports that less than 6% of
surface water systems surveyed had raw water TOC levels less than 1 mg/
L and more than 50% had raw water TOC levels greater than 3 mg/L. In
fact, this survey reports that more than 85% of surface water systems
had finished water TOC levels greater than 1 mg/L.
The NAS Report addressed several important potential risk-risk
tradeoffs associated with reducing radon levels in drinking water,
including the trade-off between risk reduction from radon treatment
that includes post-disinfection with the increased potential for DBP
formation (NAS 1999b). The report concluded that, based upon median and
average total trihalomethane (THM) levels taken from a 1981 survey,
ground water systems would face an incremental individual lifetime
cancer risk due to chlorination
[[Page 59331]]
byproducts of 5 x 10-5. It should be emphasized that this
risk is based on average and median Trihalomethane (THM) occurrence
information that does not segregate systems that disinfect from those
that do. It should also be noted that this survey pre-dates the
promulgation of the Stage I Disinfection Byproducts Rule by almost
twenty years. Further, the NAS Report points out that this average DBP
risk is smaller than the average individual lifetime fatal cancer risk
associated with baseline radon exposures from ground water (untreated
for radon), which is estimated at 1.2 x 10-4 using a mean
radon concentration of 213 pCi/L.
While this risk comparison is instructive, a more meaningful
relationship for the proposed radon rule would be to compare the trade-
off between radon risk reduction from radon treatment and introduced
DBP risk from disinfection added along with radon treatment. EPA
emphasizes that this risk trade-off is only of concern to the small
minority (<1%) of="" small="" ground="" water="" systems="" with="" radon="" levels="" above="" the="" amcl="" of="" 4000="" pci/l="" and="" to="" the="" small="" minority="" of="" large="" ground="" water="" systems="" that="" are="" not="" already="" disinfecting.="" presently,="" approximately="" half="" of="" all="" small="" community="" ground="" water="" systems="" already="" have="" disinfection="" in="" place,="" as="" shown="" in="" table="" xiii.5.="" the="" proportion="" of="" systems="" having="" disinfection="" in="" place="" increases="" as="" the="" system's="" size="" increases;="">95% of large ground water systems currently disinfect. In
terms of the populations served, 83% of persons served by small
community ground water systems (those serving 10,000 persons or fewer)
already receive disinfected drinking water and 95% of persons served by
large ground water systems already receive disinfected drinking water.
As shown in Tables XIII.16 and XIII.17, even for those ground water
systems adding both radon treatment and disinfection, this risk-risk
trade-off tends to be very favorable, since the risk reduction from
radon removal greatly outweighs the added risk from DBP formation.
An estimate of the risk reduction due to treatment of radon in
water for various removal percentages and finished water concentrations
is provided in Table XIII.16. These risk reductions are much greater
than NAS's estimate of the average lifetime risk from DBP exposure for
ground water systems, by factors ranging from 3.5 for low radon removal
efficiencies (50%) to more than 130 for higher radon removal
efficiencies (>95%).
Table XIII.16.--Radon Risk Reductions Resulting from Water Treatment
------------------------------------------------------------------------
Required Reduced lifetime risk
Radon Influent (Raw Water) level, removel resulting from Water
pCi/L efficiency Treatment for Radon in
(percent) Drinking Water \1\
------------------------------------------------------------------------
500.............................. 52 1.7 x 10 -\4\
750.............................. 68 3.4 x 10 -\4\
1000............................. 76 5.1 x 10 -\4\
2500............................. 90 1.5 x 10 -\3\
4000............................. 94 2.5 x 10 -\3\
10000............................ 98 6.5 x 10 -\3\
------------------------------------------------------------------------
\1\ Assumes that water is treated to 80% of the radon MCL.
Table XIII.17 demonstrates the risk-risk trade-off between the risk
reduction from radon removal and the risks introduced from total
trihalomethanes (TTHM) for two scenarios: (1) the resulting TTHM level
is 0.008 mg/L (10% of the TTHM MCL) and (2) the resulting TTHM level is
0.080 mg/L (the TTHM MCL). The table demonstrates that the risk-risk
trade-off is favorable for treatment with disinfection, even for
situations where radon removal efficiencies are low (50%) and TTHM
levels are present at the MCL. While accounting quantitatively for the
increased risk from DBP exposure for systems adding chlorination in
conjunction with treatment for radon may somewhat decrease the
monetized benefits estimates, disinfection may also produce additional
benefits from the reduced risks of microbial contamination.
Table XIII.17.--Radon Risk Reduction from Treatment Compared to DBP
Risks
------------------------------------------------------------------------
Estimated risk ratios: (lifetime risk
reduction from radon removal \1\ /
lifetime average risk from TTHMs in
chlorinated groundwater)
Radon influent (Raw Water) level --------------------------------------
pCi/L TTHMs
present at TTHMs
(NAS) \2\ 10% of TTHM present at
MCL (0.080 MCL
mg/L) \3\
------------------------------------------------------------------------
500.............................. 4 30 3
750.............................. 7 60 6
1000............................. 10 90 9
2500............................. 30 300 30
4000............................. 50 500 50
10000............................ 130 1200 120
------------------------------------------------------------------------
Notes: \1\ From Table XIII.16.
\2\ From Appendix D in: National Research Council, Risk Assessment of
Radon in Drinking Water, National Academy Press, Washington, DC. 1999.
DBP concentrations are from a 1981 study and therefore pre-date the
Stage 1 DBP NPDWR.
\3\ US EPA Regulatory Impact Analysis for the Stage 1 Disinfectants/
Disinfection Byproducts Rule. Prepared by The Cadmus Group. November
12, 1998. Analysis is based on the 95% upper confidence interval value
from the Integrated Risk Information System (IRIS) lifetime unit risks
for each THM. TTHM is assumed to comprised by 70% chloroform, 21%
bromodichloromethane, 8% dibromochloromethane, and 1% bromoform.
\4\ US EPA. Regulatory Impact Analysis for the Stage 1 Disinfectants/
Disinfection Byproducts Rule. Based on the 95% upper confidence
interval value from the Integrated Risk Information System (IRIS) for
the lifetime unit risk for dibromochloromethane (2.4 x 10 -\6\ risk
of cancer case over 70 years of exposure).
[[Page 59332]]
7. Other Factors: Uncertainty in Risk, Benefit, and Cost Estimates
Estimates of health benefits from radon reduction are uncertain.
EPA is including an uncertainty analysis of radon in drinking water
risks in Section XII of the preamble to the proposed radon rule. A
brief discussion on the uncertainty analysis is also shown in Section
10 of the RIA (USEPA 1999f) for radon in drinking water. Monetary
benefit estimates are also affected by the VSL estimate that is used
for fatal cancers. The WTP valuation for non-fatal cancers has less
impact on benefit estimates because it contributes less than 1 percent
to the total benefits estimates, due to the fact that there are few
non-fatal cancers relative to fatal cancers and they receive a much
lower monetary valuation.
8. Costs and Benefits of Multimedia Mitigation Program Implementation
Scenarios
In addition to evaluating the costs and benefits across a range of
radon levels, EPA has evaluated five scenarios that reduce radon
exposure through the use of MMM programs. The implementation
assumptions for each scenario are described in the next section. These
five scenarios are described in detail in Section 9 of the RIA. For the
MMM implementation analysis, systems were assumed to mitigate water to
the 4,000 pCi/L Alternative Maximum Contaminant Level (AMCL), if
necessary, and that equivalent risk reduction between the AMCL and the
radon level under evaluation would be achieved through a MMM program.
Therefore, the actual number of cancer cases avoided is the same for
the MMM implementation scenarios as for the water mitigation only
scenario. A complete discussion on why MMM is expected to achieve equal
or greater risk reduction is shown in Section VI.B of the preamble for
the proposed radon rule.
For the RIA, EPA used a simplified approach to estimating costs of
mitigating indoor air radon risks. A point estimate of the average cost
per life saved under the current voluntary radon mitigation programs
served as the basis for estimating the costs of risk reduction under
the MMM options. The Agency has estimated the average screening and
mitigation cost per fatal lung cancer avoided to be approximately
$700,000, assuming the current distribution of radon in indoor air,
that all homes would be tested for radon in indoor air, and that all
homes at or above EPA's voluntary action level of 4 pCi/L would be
mitigated. This value was originally derived based on data gathered in
1991. The same value has been used in the RIA, without adjustment for
inflation, after discussions with personnel from EPA's Office of
Radiation and Indoor Air indicated that screening and mitigation costs
have not increased since 1991.
9. Implementation Scenarios
EPA evaluated the annual cost of five MMM implementation scenarios
that span the range of participation in MMM programs that might occur
when a radon NPDWR is implemented. Each scenario assumes a different
proportion of States will comply with the AMCL and implement MMM
programs. It has been assumed that ``50 percent of States'' implies 50
percent of systems in the U.S; ``60 percent of States'' implies 60
percent of systems, and so on.
Scenario A: 50 percent of States implement MMM programs.
Scenario B: 60 percent of States implement MMM programs.
Scenario C: 70 percent of States implement MMM programs.
Scenario D: 80 percent of States implement MMM programs.
Scenario E: 95 percent of States implement MMM programs.
States that do not implement MMM programs instead must review and
approve any system-level MMM programs prepared by community water
systems. In these States, regardless of scenario, 90 percent of systems
are assumed to comply with the AMCL and to implement a system-level MMM
program and 10 percent are assumed to comply with the MCL. EPA requests
comment on whether this is an appropriate assumption.
10. Costs and Benefits of MMM Implementation Scenarios
Table XIII.18 shows the total annual system-level and State-level
costs for each MMM scenario, assuming an MCL of 300 pCi/L and AMCL of
4,000 pCi/L. Additional MMM scenario cost and benefit tables for MCL
levels of 100, 500, 700, 1000, 2000, and 4000 pCi/L are shown in
Appendix E of the RIA. System, State, and MMM mitigation costs decrease
from $121.1 million to $60.4 million as the percentage of States
implementing MMM programs increases from 50 to 95 percent. System-level
costs decrease from $104 million to $47 million as the percentage of
States implementing MMM programs increases from 50 to 95 percent. Costs
for actual mitigation of radon in indoor air rise from $3.9 million to
$4.1 million as the percentage of States implementing MMM programs
rises from 50 to 95 percent. Note that these mitigation costs are
relatively flat because all scenarios assume that 95 percent or more of
the risk reduction will be achieved through MMM at either the State or
local level.
Table XIII.19 represents the ratios of benefits to costs of MMM
programs for each scenario, by system size. Only the ratios in the
bottom row of the table include costs to the States. The balance of the
numbers presented here represent local benefits and costs only and as
such, somewhat overstate the net benefits of the scenarios. Benefit-
cost ratios are generally less than one for the smallest system size
category (systems serving less than 500 people), but greater than one
for larger systems under all five scenarios. For larger systems,
benefit-cost ratios range from 2.6 for systems serving 501-3,300 people
under Scenario A to approximately 41.4 for systems serving 10,001 to
100,000 people under Scenario E. Overall benefit-cost ratios are over
one for all five scenarios. This pattern is seen primarily because a
larger proportion of smaller systems have influent radon levels
exceeding 4000 pCi/L. A larger proportion of small systems versus large
systems therefore, incur water mitigation costs to comply with the
AMCL.
Table XIII.20 shows the net benefits (benefits minus costs) of the
various MMM implementation scenarios. As would be expected from the
benefit-cost ratios shown in Table XIII.19, all systems serving more
than 500 people realize net positive benefits under all five scenarios.
By far the largest proportion of net benefits is realized by systems
serving 10,001 to 100,000 people.
[[Page 59333]]
Table XIII.18 (A).--Annual System--Level and State--Level Costs Associated with the Multimedia Mitigation and
AMCL Option
[$ Millions/Year] [MCL=300 pCi/L]
----------------------------------------------------------------------------------------------------------------
Scenario A Scenario B Scenario C Scenario D Scenario E 5%
45% implement 36% implement 27% implement 18% implement implement
system-level system-level system-level system-level system-level
MMM program; MMM program; MMM program; MMM program; MMM program;
5% mitigate 4% mitigate 3% mitigate 2% mitigate 5% mitigate
System size water to 300 water to 300 water to 300 water to 300 water to 300
piC/L MCL; 95% piC/L MCL; 96% piC/L MCL; 97% piC/L MCL; 98% piC/L MCL;
mitigate water mitigate water mitigate water mitigate water 99.5% mitigate
to 4000 piC/L to 4000 piC/L to 4000 piC/L to 4000 piC/L water to 4000
AMCL AMCL AMCL AMCL piC/L AMCL
----------------------------------------------------------------------------------------------------------------
System Costs for Water Mitigation ($ millions/year)
----------------------------------------------------------------------------------------------------------------
25-100.......................... 10.2 9.7 9.3 8.8 8.1
101-500......................... 17.6 16.9 16.3 15.6 14.6
501-3300........................ 9.9 9.2 8.5 7.7 6.7
3301-10,000..................... 5.5 5.0 4.5 3.9 3.1
10,001-100,000.................. 7.5 6.6 5.6 4.6 3.2
>100,000........................ 2.0 1.7 1.4 1.1 0.7
-------------------------------------------------------------------------------
Total CWS Water Mitigation 52.7 49.1 45.4 41.8 36.3
Costs......................
----------------------------------------------------------------------------------------------------------------
Water System Administration Costs ($ millions/year)
----------------------------------------------------------------------------------------------------------------
25-100.......................... 17.0 14.0 11.0 8.0 3.7
101-500......................... 17.4 14.3 11.3 8.2 3.8
501-3300........................ 12.0 9.9 7.8 5.7 2.6
3301-10,000..................... 3.0 2.5 1.9 1.4 0.6
10,001-100,000.................. 1.7 1.4 1.1 0.8 0.4
>100,000........................ 0.1 0.1 0.1 0.0 0.0
-------------------------------------------------------------------------------
Total CWS Administrative 51.2 42.1 33.1 24.1 11.1
Costs......................
===============================================================================
Total CWS Water 104.0 91.2 78.5 65.9 47.4
Mitigation and
Administrative Costs...
----------------------------------------------------------------------------------------------------------------
Table XIII.18 (B).--State MMM Administrative Costs
[$ millions/year]
----------------------------------------------------------------------------------------------------------------
Scenario A 50% Scenario B 60% Scenario C 70% Scenario D 80%
of states of states of states of states Scenario E 95%
implement implement implement implement of states
state-wide MMM state-wide MMM state-wide MMM state-wide MMM implement
programs; 45% program; 35% program; 25% program; 15% state-wide MMM
of CWS of CWS of CWS of CWS program; 5% of
implement implement implement implement CWS implement
system-level system-level system-level system-level system-level
MMM program MMM program MMM program MMM program MMM program
----------------------------------------------------------------------------------------------------------------
State costs associated with State-wide MMM program administration, reviewing system-level MMM programs, and
reviewing system-level water mitigation requirements are not distributable across different system sizes.
----------------------------------------------------------------------------------------------------------------
State Administration Costs for 2.5 2.5 2.5 2.5 2.5
Water Mitigation...............
State Administration Costs for 2.9 3.5 4.1 4.7 5.6
State-Level MMM Mitigation.....
State Administration Costs for 7.8 6.1 4.4 2.6 0.9
System-Level MMM Mitigation....
-------------------------------------------------------------------------------
Total State 13.2 12.1 10.9 9.8 8.9
Administration Costs...
----------------------------------------------------------------------------------------------------------------
Table XIII.18 (C).--MMM Testing and Mitigation Costs
[$ million/year]
----------------------------------------------------------------------------------------------------------------
Scenario A Scenario B Scenario C Scenario D Scenario E
----------------------------------------------------------------------------------------------------------------
CWS MMM Costs................... 1.9 1.5 1.1 0.7 0.2
State MMM Costs................. 2.1 2.5 2.9 3.3 3.9
-------------------------------------------------------------------------------
Total MMM Costs............. 3.91 3.95 3.99 4.03 4.12
===============================================================================
[[Page 59334]]
Total Costs (From Tables 121.1 107.3 93.4 79.7 60.4
XIII.18 A, B, and C)...
----------------------------------------------------------------------------------------------------------------
Table XIII.19.--Ratio of Benefits and Costs by System Size for Each Scenario (MCL=300 pCi/L)
--------------------------------------------------------------------------------------------------------------------------------------------------------
System size Benefits, $M Scenario A Scenario B Scenario C Scenario D Scenario E
--------------------------------------------------------------------------------------------------------------------------------------------------------
25-100................................................. 3.5 0.13 0.14 0.17 0.21 0.30
101-500................................................ 16.9 0.48 0.53 0.61 0.70 0.92
501-3,300.............................................. 58.0 2.59 2.98 3.51 4.27 6.23
3,301-10,000........................................... 59.2 6.87 7.85 9.16 11.0 15.61
10,001-100,000......................................... 147.3 15.82 18.35 21.84 26.96 41.43
>100,000............................................... 76.7 37.16 43.70 53.04 67.44 113.68
------------------------------------------------------------------------------------------------
OVERALL........................................ 361.6 2.98 3.37 3.87 4.54 5.99
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table XIII.20.--Net Benefits by System Size for Each Scenario \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
System size Benefits, $M Scenario A Scenario B Scenario C Scenario D Scenario E
--------------------------------------------------------------------------------------------------------------------------------------------------------
25-100.................................................. 3.5 (24.3) (20.7) (17.1) (13.5) (8.3)
101-500................................................. 16.9 (18.7) (14.8) (11.0) (7.1) (1.6)
501-3,300............................................... 58.0 35.6 38.6 41.5 44.4 48.7
3,301-10,000............................................ 59.2 50.6 51.7 52.7 53.8 55.4
10,001-100,000.......................................... 147.3 138.0 139.3 140.6 141.8 143.7
>100,000................................................ 76.7 74.6 74.9 75.3 75.6 76.0
-----------------------------------------------------------------------------------------------
OVERALL......................................... 361.6 240.5 254.3 268.2 281.9 301.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Parentheses indicate negative numbers.
H. Response to Significant Public Comments on the February 1999 HRRCA
To provide the public with opportunities to comment on the Health
Risk Reduction and Cost Analysis (HRRCA) for radon in drinking water,
the Agency published the HRRCA in the Federal Register on February 26,
1999 (64 FR 9559). The HRRCA was published six months in advance of
this proposal and illustrated preliminary cost and benefit estimates
for various MCL options under consideration for the proposed rule. The
comment period on the HRRCA ended on April 12, 1999, and EPA received
approximately 26 written comments from a variety of stakeholders,
including the American Water Works Association, the National Rural
Water Association, the National Association of Water Companies, the
Association of Metropolitan Water Agencies, State departments of
environmental protection, State health departments, State water
utilities and local water utilities.
Significant comments on the HRRCA addressed the topics of radon
occurrence, exposure pathways, sensitive sub-populations and the risks
to smokers, risks from existing radon exposures, risks associated with
co-occurring contaminants, risk increases associated with radon
removal, the benefits of reduced radon exposures, the costs of radon
treatment measures, the cost and benefit results, and the Multimedia
Mitigation (MMM) program. The following discussion outlines the
significant comments received on the HRRCA and the Agency's response to
these comments.
1. Radon Occurrence
Several commenters had concerns related to EPA's analysis of radon
occurrence. Two commenters felt that the radon levels in Table 3.1 of
the HRRCA were too low and not representative of radon occurrence in
their regions. A California water utility indicated that due to
limitations of the NIRS, EPA should conduct a new national radon
survey, with special emphasis on determining radon levels in the
largest systems, before promulgating the rule. Two commenters from
Massachusetts expressed concerns about radon occurrence. One suggested
that additional analysis of radon variability in individual wells was
required, and another indicated that the effects of storage and
residence time on radon levels in supply systems needed to be taken
into account. One commenter indicated that EPA should more strongly
consider that most risk reductions predicted in the HRRCA come from
reductions in radon levels in the small proportions of systems with
initial very high radon levels.
EPA Response 1-1
As part of the regulatory development process, EPA updated and
refined its analysis of radon occurrence patterns in ground water
supplies in the United States. This new analysis incorporated
information from the EPA 1995 National Inorganic and Radionuclides
Survey (NIRS) of 1000 community ground water systems throughout the
United States, along with supplemental data provided by States, water
utilities, and academic researchers. EPA's current re-evaluation used
data from 17 States to determine the differences between radon levels
in ground water and radon levels in distribution systems in the same
regions. The results of these comparisons were used to estimate
national distributions of radon occurrence in ground water. EPA
believes that the existing NIRS data, along with the Agency's updates
to this data, currently provide the most comprehensive national-level
analysis of radon occurrence patterns in ground water supplies. This
analysis is not intended for the estimation of radon occurrence at the
state-level.
[[Page 59335]]
Variability within the NIRS radon occurrence data was analyzed for
several important contributing factors: within-well (temporal)
variability, sampling and analytical (methods) variability, intra-
system variability (variability between wells within a single system),
and inter-system variability (variability between wells in different
systems). Several important conclusions were drawn from this analysis.
First and foremost is the conclusion that the NIRS data do capture the
major sources of radon occurrence variability and thus can be used
directly, without any additional correction for temporal or sampling
and analytical variability, to provide reasonable national estimates of
radon levels and variability levels in ground water drinking supplies.
In addition, EPA analyzed the additional data sets provided from
stakeholders (described previously) in conjunction with the NIRS radon
data to estimate the magnitudes of the variability sources. Based on
all of these analyses, EPA has concluded that the variability between
systems dominates the over-all variability (it comprises approximately
70 percent of the over-all variability). Temporal variability (13-18
percent), sampling and analytical variability (less than 1 percent),
and intra-system variability (12-17 percent) are relatively minor by
comparison. These results are discussed in detail elsewhere (USEPA
1999b).
Note: These estimates of variability sources apply to national-
level radon occurrence estimates: individual regions may have
systems that show variability sources that deviate significantly
from these values.
This analysis of variability was incorporated into EPA's estimates of
nation-wide radon occurrence and was used in its estimates of the
effects of uncertainty in occurrence information on total national
costs of compliance.
In response to the comment that ``most risk reductions predicted in
the HRRCA come from reductions in radon levels in the small proportions
of systems with initial very high radon levels'', EPA agrees that a
system with high radon levels would benefit more from water mitigation
than a system with much lower initial radon levels, but the vast
majority of the national water mitigation benefits come from systems
that are above the MCL, but not that high above it (e.g., 80 percent
removal required for the system to be at the MCL). This is true since
radon is approximately log-normally distributed (i.e., a much higher
percentage of water systems can be expected to have relatively low
radon levels than relatively high radon levels) and hence most systems
fall into this category. For this reason, the summation of these
smaller per system benefits enjoyed by the large number of systems
nearer the MCL greatly outweigh summation of the larger per system
benefits enjoyed by the minority of systems with very high radon
levels. This is demonstrated in Table 6-2 of the HRRCA (``Estimated
Monetized Benefits from Reducing Radon in Drinking Water''), in which
the central tendency estimate of monetized benefits associated with an
MCL of 500 pCi/L is 212 million dollars and the benefits associated
with an MCL of 100 pCi/L is 673 million dollars. This means that, in
the latter case, 461 million dollars of the benefits come just from the
systems with radon levels between 100 and 500 pCi/L (80 percent removal
required), while the remaining benefits (212 million dollars) come from
the systems with radon levels from 500 pCi/L up to the highest radon
levels.
Five commenters indicated that the estimates of the numbers of
entry points per system used in the HRRCA were incorrect, in that large
systems had far more entry points than the numbers given in Table 5.4
of the HRRCA. Several of these commenters cited data from the Community
Water System Survey (CWSS), showing higher numbers of wells per system
in each system size category than were used for cost calculations in
the HRRCA.
EPA Response 1-2
The relevant distribution for costing out non-centralized treatment
is the number of entry points, not the number of wells. A given entry
point (the point at which treatment is applied) may be fed by several
wells, and hence there is a discrepancy in numbers between the HRRCA,
which reported a distribution of entry points, and Table 1-5 of the
Community Water System Survey (CWSS), which reported the average number
of wells per system. These numbers are related, but not directly
comparable. In general, the average number of entry points for a class
of ground water systems would be expected to be smaller than the
average number of wells. In the HRRCA, the distribution of entry points
per system was estimated from a statistical analysis (``bootstrap
analysis'') of the well and entry point data from the CWSS. This
statistically-calculated distribution was then used to estimate the
percentage of systems within a system size category having a given
number of entry points. However, as part of its uncertainty analysis,
EPA has used the 95% confidence upper bound of the site distribution in
the national cost estimates supporting this proposal. The average
number of entry points per system is roughly 10% higher using this
upper bound analysis. In addition, to test the effects of varying this
distribution on the national costs of compliance, the per system costs,
and the per household costs, EPA conducted an uncertainty analysis
(Monte Carlo analysis including sensitivity) on the distribution by
simultaneously varying both the percentages of systems estimated to
have a particular number of sites and the estimated number of sites.
The results of this analysis are reported both in this notice and in
the Regulatory Impact Analysis. It should be noted that the treatment
unit costs and total number of systems dominated the cost uncertainty
and that the entry point distribution was a relatively minor
contributor to the overall cost uncertainty.
2. Exposure Pathways
A number of issues related to radon exposure pathways were raised.
Several commenters indicated that the risks associated with the build-
up of radon in carbon filters needed to be addressed in HRRCA. Concerns
were also expressed about general population exposures to radon in air
released from aeration facilities and exposures to workers at water
utilities. Another commenter said that EPA should discuss the
persistence of radon in the body after ingestion.
EPA Response 2-1
The risks from radon build-up in carbon filters and radon off-gas
emissions are discussed in some detail in this notice, including an
evaluation of risks, a discussion of references, and responses from a
survey of air permitting boards about the permitting of radon off-gas.
EPA Response 2-2
The persistence of radon in the body following ingestion has been
investigated and the results have been presented in the Criteria
Document for Radon (USEPA 1999b). In brief, radon ingested in water is
well-absorbed from the stomach and small intestine into the bloodstream
and transported throughout the body. Radon is rapidly (within
approximately one hour) excreted from the body via the lungs, so only
about 1 percent of ingested radon undergoes radioactive decay while in
the body. The risks from the retained radon and its decay products in
various organs are calculated by NAS and adopted by EPA in the proposed
rule.
[[Page 59336]]
3. Nature of Health Impacts
No comments were made concerning the general nature of adverse
effects associated with radon exposure. Comments concerning specific
aspects of health impact evaluation are summarized in the following
sections.
(a) Sensitive subpopulations, risks to smokers, non-smokers.
Comments on these sections are addressed together because the majority
of the comments had to do with the characterization of smokers as a
sensitive population. Several commenters noted that most risk reduction
from reducing radon exposure occurs among smokers, and took the
position that EPA should not include risk reductions to smokers in its
benefits assessment, because smoking can be viewed as a voluntary risk.
One commenter suggested that the smokers' willingness to pay for
cigarettes also indicated a willingness to face the risk of smoking.
EPA Response 3-1
The term, ``groups within the general population'' is addressed,
but not comprehensively defined, in the 1996 amendments to the Safe
Drinking Water Act (SDWA, Sec. '1412(b)(3)(C)). The definition of
sensitive subpopulations is an issue for discussion and debate, and EPA
is interested in input from stakeholders. The National Academy of
Sciences (NAS) Radon in Drinking Water Committee, as part of their
assessment of the risks of radon in drinking water, has considered
whether groups within the general population, including smokers, may be
at increased risk. The NAS Committee has indicated, in their Risk
Assessment of Radon in Drinking Water report, that smokers are the only
group within the general population that is more susceptible to
inhalation exposure to radon progeny, but did not specifically identify
smokers as a sensitive subpopulation.
In this proposal, EPA is basing its risk management decision on
risks to the general population. The general population includes
smokers as well as former smokers. The risk assessments for radon in
air and water are based on an average member of the population, which
includes smokers, former smokers, and non-smokers. A more complete
discussion on the risks of radon in drinking water and air is presented
in the NAS's risk assessment report and in Section XII of this
preamble.
(b) Risk reduction model, risks from existing radon exposures.
Commenters raised only one concern associated with the risk model used
to estimate radon reduction benefits. Three commenters suggested that
EPA should consider adopting a threshold-based model for radon
carcinogenesis, and that EPA's current (non-threshold) approach
overestimates radon risks. In support, the commenters cited a recently
published paper (Miller et al, 1999) as providing evidence that a
single alpha particle ``hit'' typical in low-level radon may not be
sufficient to cause cell transformation leading to cancer.
EPA Response 3-2
There are a number of papers that have recently examined the
effects of a single alpha particle on a cell nucleus of mammalian cells
in culture. The authors of this study concluded that cells were more
likely to be transformed to cancer causing cells if there were multiple
alpha particle hits to their nuclei. However, another study, Hei et al.
(1997), using a similar methodology, found direct evidence that a
single ``particle traversing a cell nucleus will have a high
probability of resulting in a mutation'' and concluded that their work
highlighted the need for radiation protection at low doses. Moreover,
follow-up microbeam experiments described by Miller et al. at the 1999
International Congress of Radiation Research demonstrated that one
alpha particle track through the nucleus was indeed sufficient to
induce transformation under some experimental conditions.
Epidemiological data relating to low radon exposures in mines also
indicate that a single alpha track through the cell may lead to cancer.
Finally, while not definitive by themselves, the results from
residential case-control studies provide some direct support for the
conclusion that environmental levels of radon pose a risk of lung
cancer. EPA has based its current risk estimates for radon in drinking
water on the findings of the National Academy of Sciences. Rather than
focus on the results of any one study, the NAS committees based their
conclusions on the totality of data on radon--a weight-of-evidence
approach.
Both the BEIR VI Report (NAS 1999a) and their report on radon in
drinking water (NAS 1998b) represent the most definitive accumulation
of scientific data gathered on radon since the 1988 NAS BEIR IV (NAS
1988). These committees' support for the use of linear-non-threshold
relationship for radon exposure and lung cancer risk came primarily
from their review of the mechanistic information on alpha-particle-
induced carcinogenesis, including studies of the effect of single
versus multiple hits to cell nuclei.
In the BEIR VI report (NAS 1999a), the NAS concluded that there is
good evidence that a single alpha particle (high-linear energy transfer
radiation) can cause major genomic changes in a cell, including
mutation and transformation that potentially could lead to cancer. They
noted that even if substantial repair of the genomic damage were to
occur , ``the passage of a single alpha particle has the potential to
cause irreparable damage in cells that are not killed.'' Given the
convincing evidence that most cancers originate from damage to a single
cell, the committee went on to conclude that ``on the basis of these
[molecular and cellular] mechanistic considerations, and in the absence
of credible evidence to the contrary, the committee adopted a linear-
nonthreshold model for the relationship between radon exposure and
lung-cancer risk. However, the BEIR VI committee recognized that it
could not exclude the possibility of a threshold relationship between
exposure and lung cancer risk at very low levels of radon exposure.''
The NAS committee on radon in drinking water (NAS 1999b) reiterated the
finding of the BEIR VI committee's comprehensive review of the issue,
that a ``mechanistic interpretation is consistent with linear, non-
threshold relationship between radon exposure and cancer risk''. The
committee noted that the ``quantitative estimation of cancer risk
requires assumptions about the probability of an exposed cell becoming
transformed and the latent period before malignant transformation is
complete. When these values are known for singly hit cells, the results
might lead to reconsideration of the linear no-threshold assumption
used at present.'' EPA recognizes that research in this area is on-
going but is basing its regulatory decisions on the best currently
available science and recommendations of the NAS that support use of a
linear non-threshold relationship.
(c)Risk and risk reduction associated with co-occurring
contaminants. Several commenters addressed the issue of risks
associated with co-occurring contaminants. Other commenters indicated a
need to include risks and risk reductions from co-occurring
contaminants.
EPA Response 3-3
The contaminants that may co-occur with radon that are of main
concern are those that can cause fouling of aeration units (or
otherwise impede treatment) and those that are otherwise affected by
the aeration process in such a way as to increase risks. Measures and
costs to avoid aeration fouling are discussed in
[[Page 59337]]
this notice and in the references cited. Arsenic co-occurrence may be
relevant since some systems may have to treat for both, but the
treatment processes are not incompatible. In fact, the only side-effect
of the aeration process that may impact the removal of arsenic would be
the potential oxidation of some fraction of less easily removed As(IV)
form to the more easily removed As(VI) form. There would be no
additional costs due to this effect, and in fact, there may be cost
savings involved. The potential for increased risks due to potential
disinfectant by-product formation after disinfection, is discussed
next.
(d) Risk increases associated with radon removal. Five commenters
said that EPA should include quantitative estimates of the risk
increases associated with increased exposure to disinfection byproducts
(DBPs) in the risk and cost-benefit analyses of the HRRCA. One
commenter said that risks should be apportioned appropriately between
the proposed radon rule and the Groundwater rule. Another commenter
maintained that, contrary to the assertion in the HRRCA, there would be
no reduction in microbial risks due to the increased disinfection
associated with the radon rule because most groundwater sources
currently present no microbial risks.
EPA Response 3-4
EPA would like to highlight that the AMCL/MMM option is the
preferred option for all drinking water systems, which would result in
very few water treatment systems adding disinfection. EPA expects the
radon rule to result in a minority of ground water systems choosing the
MCL option, and of those, many will be larger systems. Since very few
small systems are expected to choose the MCL option , very few systems
are above the AMCL of 4000 pCi/L, and most large ground water systems
already disinfect their water, few systems are expected to add
disinfection in response to the radon rule, i.e., increased risk due to
disinfection by-product formation should not be a significant issue.
However, EPA does evaluate this risk-risk trade-off in this notice for
that minority of systems that will be expected to add disinfection with
treatment for radon. For that minority of systems, the trade-off
between decreased risks from radon and increased risks from
disinfection-by-products is favorable.
4. Benefits of Reduced Radon Exposure
The majority of the comments related to the estimation of benefits
focused on the methods used to monetize reductions in cancer risks.
There were also a few comments on non-quantifiable benefits, and on
several other topics. The previous comments pertaining to risk
reductions to smokers and that benefits from these risk reductions
should be excluded from the HRRCA apply here as well.
(a) Nature of regulatory benefits. There were few comments on this
section, most of which pertained to non-quantifiable benefits. One
commenter indicated that the peace-of-mind non-quantifiable benefit
from radon reduction would be offset by the anxiety of those living
near aeration plants. Another noted that peace-of-mind benefits were
not easy to quantify for non-threshold pollutants like radon and, in
fact, that the regulation of radon might actually increase anxiety by
drawing attention to the risks associated with radon exposures.
Commenters also noted that claiming arsenic reduction as a benefit from
aeration is questionable because there is no demonstrated correlation
between the levels of radon and arsenic in groundwater systems.
EPA Response 4-1
By definition, non-quantifiable benefits cannot be measured and
have not been measured in the HRRCA analysis. Thus, comparisons of
types of such benefits are not very meaningful. EPA attempts to note
these potential benefits when the Agency believes they might occur, as
in the case of peace-of-mind benefits from radon reduction. There may
also be non-quantifiable costs that may offset any non-quantifiable
benefits. These include anxiety on the part of residents near treatment
plants and customers who may not have previously been aware of radon in
their water. As noted elsewhere in this preamble, EPA believes it
unlikely that accounting for these non-quantifiable benefits and costs
quantitatively would significantly alter the overall assessment.
(b) Monetization of benefits. Comments related to risk reduction
have been discussed in previous responses, so are not discussed further
here. Commenters addressed all three approaches to monetizing benefits:
the value of statistical life; the costs of illness; and willingness-
to-pay. A number of commenters suggested the use of Quality-Adjusted
Life Years (QALY) as an alternative approach to the valuation of health
benefits. One commenter indicated that the use of QALYs was a good way
to avoid having to monetize health outcomes. Two commenters indicated
that QALYs had the advantage of being able to take into account the
delayed onset of cancer, as well as reduced incidence. One organization
suggested QALYs as a superior method for combining the benefits from
fatal and non-fatal illness over different time periods; which would be
particularly useful in the case of smokers, whose cancers are likely to
be delayed, but not necessarily prevented, by reductions in radon
exposure.
EPA Response 4-2
The use of QALYs has been extensively discussed within EPA and also
before the Environmental Economics Advisory Committee of EPA's Science
Advisory Board. At this time, current Agency policy is to use Value of
Statistical Life (VSL) estimates for the monetization of risk reduction
benefits. EPA believes QALY calculations to be experimental and not
well established for the types of analyses performed by the Agency.
(c) Value of statistical life (VSL). Several commenters questioned
the use of, or the value selected for, the value of statistical life as
a measure of benefits. Other commenters indicated that the large range
of uncertainty associated with the estimates of risk reduction called
the VSL (and the willingness-to-pay) methods into question, and
indicated that EPA needed to better justify the central-tendency VSL
value selected for use in the HRRCA. They maintained that the VSL
approach would only be appropriate if the VSL estimates were derived
from ``similar scenarios'' to those being evaluated in the HRRCA.
Another commenter suggested that using the VSL was inappropriate in
that the VSL dollars did not represent (as do compliance costs) actual
resource losses to society that could be spent on other programs (e.g.
pollution reduction). Thus, the comparison of compliance costs to VSL
costs is not valid. They strongly recommend the use of compliance cost
per life saved as an appropriate measure for judging radon control
options. One commenter indicated that the use of the VSL approach
resulted in greatly over-estimated benefits of radon exposure
reduction, particularly because the VSL for smokers is the same as for
non-smokers and does not account for the age at which mortality is
avoided. Another questioned the validity of the mean VSL value used in
the HRRCA, and indicated that VSL estimates should only come from the
peer-reviewed scientific literature or from Agency documents that had
been subject to public comment.
[[Page 59338]]
EPA Response 4-3
The VSL value, currently recommended by Agency guidance, is derived
from a statistical distribution of the values found in twenty-six VSL
studies, which were chosen as the best such studies available from a
larger body of studies. This examination of studies was undertaken by
EPA's Office of Air and Radiation in the course of its Clean Air Act
retrospective analysis. EPA believes the VSL estimate ($5.8 million,
1997 dollars) to be the best estimate at this time, and is recommending
that this value be used by the various program offices within the
Agency. This estimate may, however, be updated in the future as
additional information becomes available to assist the Agency in
refining its VSL estimate. The VSL estimate is consistent with current
Agency economic analysis guidance, which was recently peer reviewed by
EPA's Science Advisory Board.
d. Costs of illness (COI). Two commenters suggested that EPA should
further review the literature on the costs of illness and develop
better cost measures for the illnesses addressed in the HRRCA.
EPA Response 4-4
EPA believes that the COI data is the most complete analysis of
this type currently underway. The cost of illness (COI) data shown in
the HRRCA were presented as a comparison to Willingness to Pay (WTP) to
avoid chronic bronchitis. The Agency did not use the COI data to
estimate risk reduction valuations for non-fatal cancers because these
estimates can be seen as underestimating the total WTP to avoid non-
fatal cancers. COI may understate total WTP because of its failure to
account for many effects of disease such as pain and suffering,
defensive expenditures, lost leisure time, and any potential altruistic
benefits. It is important to note that the proportion of benefits
attributable to non-fatal cancer cases accounts for less than one
percent of the total benefits in the HRRCA.
(e) Willingness-to-pay. Several commenters questioned EPA's use of
the willingness-to-pay (WTP) approach for monetizing non-fatal cancer
risk reductions. Another suggested that a WTP value for victims of non-
fatal cancers should have been used, instead of the WTP estimates for
chronic bronchitis. It was also suggested that WTP measures would vary
within the general population, and that use of a constant value was
inappropriate.
EPA Response 4-5
EPA believes that the WTP estimates to avoid chronic bronchitis are
the best available surrogate for WTP estimates to avoid non-fatal
cancers. WTP estimates were used in the HRRCA as opposed to COI to
value non-fatal cancer cases. EPA believes that COI may understate
total WTP because of its failure to account for many effects of disease
such as pain and suffering, defensive expenditures, lost leisure time,
and any potential altruistic benefits. It is important to note that the
proportion of benefits attributable to non-fatal cancer cases accounts
for less than one percent of the total benefits in the HRRCA.
(f) Treatment of benefits over time. Many commenters objected to
EPA's assumption that cancer risk reduction, and hence benefits, would
begin to accrue immediately upon the reduction of radon exposures. In
addition, they felt that the failure to discount health benefits
resulted in an overestimation of the benefits. One commenter suggested
that a ``gradual phase-in'' of risk reduction should be incorporated
into the HRRCA benefits calculation. It was also suggested that an
alternative to immediate benefits accrual be used, and that the effects
of the immediate benefits accrual assumption be discussed in detail
with regard to the uncertainties it introduces into the benefits
estimates. One commenter identified the assumption of immediate
benefits as a major source of benefits overestimation. Another comment
asked that EPA provide better justification for assuming immediate
benefits accrual, and suggests instead that a linear phase-in of risk
reduction over 70 years would be more appropriate. Three commenters
also indicate that the failure to take latency of risk reduction into
account and to discount benefits appropriately, greatly biases the
benefits estimates in the upward direction. One commenter indicated
that the failure to discount benefits resulted in a five- to ten-fold
over-estimation.
EPA Response 4-6
These comments address the issue of latency, the difference between
the time of initial exposure to environmental carcinogens and the onset
of any resulting cancer. Qualitative language has been added to the
preamble regarding adjustments, including latency, that could be made
to benefits calculations. This qualitative discussion notes that
latency is one of a number of adjustments related to an evaluation of
potential benefits associated with this rule. EPA believes that such
adjustments should be considered simultaneously. For further
discussion, see section XIII.D of the preamble.
5. Costs of Radon Treatment Measures
(a) Drinking water treatment technologies and costs. All of the
commenters had concerns related to EPA's assumptions and analyses of
costs of radon treatment measures. In fact, one commenter suggested
that the entire section was oversimplified by EPA. Most of the
commenters, however, provided more specific comments which are outlined
next.
EPA Response 5-1
Most, if not all, commenters assumed that EPA would propose that
the risks from radon would be best addressed by drinking water systems
attempting to meet the MCL. Under this scenario, many small systems
would be in situations where they faced very difficult treatment
issues, often with technically difficult and/or expensive solutions.
However, EPA is suggesting that the risks from radon are best addressed
by the combined use of the AMCL with a multi-media mitigation (MMM)
program. Since the proposal also includes a regulatory expectation of
adoption of the AMCL by small systems, EPA believes that many of the
comments received are less applicable to this proposal than if the MCL
were the preferred route of compliance.
(b) Aeration. Several commenters expressed concerns related to
aeration costs. One major concern was EPA's failure to address worker
safety issues, and the associated cost of occupational safety programs,
at treatment plants. A reference to earlier studies of increased risk
to neighbors is provided, but details are not included to evaluate
these studies. Concern was expressed that costs for permitting and
control of radon emissions from treatment plants were not included, and
that the public might react strongly to the presence of a local
treatment plant even if analysis showed the risk to be minimal. Three
commenters noted that the HRRCA failed to consider quantifiable
corrosion control costs associated with aeration. Installation of
aeration for radon removal may also affect lead/copper levels in the
water distribution system, resulting in additional treatment
modifications and costs. Many systems will have to develop a different
corrosion control strategy to comply with the lead and copper rule due
to the radon regulation.
EPA Response 5-2
Worker safety issues for aeration treatment of radon in drinking
water are discussed in today's notice (Section
[[Page 59339]]
VIII.A.3) and are discussed in more detail in other sources (USEPA
1994b, USEPA 1998h). Radon exposure to workers in drinking water
treatment plants has been discussed in the literature (e.g., Fisher et
al. 1996, Reichelt 1996). In fact, these discussions usually apply to
situations where radon is NOT the contaminant being purposely removed,
since there is currently no regulatory driver to do so. When ground
water is exposed to air during treatment for any contaminant, radon may
be released and may accumulate in the treatment facility. The National
Research Council (NAS 1999b) suggests that the air in all groundwater
facilities treating for any contaminant should be monitored for radon
and that ventilation should be investigated as a means of reducing
worker exposure. In support of this position, EPA would further
strongly suggest that systems that attempt to meet the MCL (i.e., that
are in States that do not adopt the AMCL or otherwise choose to meet
the MCL) by installing aeration treatment should take the appropriate
measures to monitor and ventilate the treatment facilities. For those
small systems that choose GAC treatment, other precautions should be
taken to monitor and control gamma exposure. GAC treatment issues are
discussed later in this notice and are discussed in detail elsewhere
(USEPA 1994b, AWWARF 1998 and 1999).
EPA has suggested that occupational exposures be limited to 100
mRem/year, a level well below the upper limit of 5000 mRem/year
approved in by the President in 1987 (``Radiation Exposure Guidance to
Federal Agencies for Occupational Exposure'', as cited in USEPA 1994b).
Based on limited data, it appears that 100 mRem/year is a maintainable
objective within water treatment plants treating for radon or other
contaminants. Exposure level monitoring and mitigation through a
combination of air monitoring and ventilation has been demonstrated to
be feasible and relatively inexpensive (e.g., Reichelt 1996).
Regarding the effects on water corrosivity and the impacts of costs
of corrosion control measures, this notice presents much more detail on
EPA's assumptions. Corrosion control measures are included in national
cost estimates and are discussed in this notice. Case study information
on corrosion control costs associated with aeration are included in the
Radon Technologies and Costs document (USEPA 1999h).
(c) GAC. Two commenters noted that the option for use of granular
activated carbon (GAC) did not address potential problems with
radioactivity buildup in the carbon. In consideration of treatment
methods the two commenters saw no mention of the cost of disposal of
GAC used for radon removal. If not replaced in time it will become a
low level radioactive waste because of Lead 210 and will become
difficult to dispose of. Other issues that need to be addressed
include: will the unit require special shielding; may the charcoal bed
be required to have a radioactive materials license from the State; and
how may radioactive carbon be disposed of?
EPA Response 5-3
Special considerations regarding GAC operations, maintenance, and
ultimate GAC unit disposal are discussed in some detail in Section
VIII.A of this notice, including discussions of the radiation hazards
involved and steps that can be taken to ameliorate these hazards. GAC
disposal costs are included in the operations and maintenance costs in
the model used for cost estimates. Comparisons of modeled GAC capital
and operations & maintenance cost estimates to actual costs reported in
case studies are included in Section VIII of this notice. EPA would
like to strongly emphasize that carbon bed lifetimes (carbon bed
replacement rates) should be designed to preclude situations where
disposal becomes prohibitively expensive or technically infeasible.
Recently, the American Water Works Association Research Foundation
has published a study on the use of GAC for radon removal, which
includes discussions of the issues described previously, that concludes
that GAC is a tenable treatment strategy for small systems when used
properly under the appropriate circumstances (AWWARF 1998a). AWWARF
also reviewed the proper use of GAC for radon removal in its recent
review of general radon removal strategies (AWWARF 1998b). When the
final radon rule is promulgated, a guidance manual will be published
describing technical issues and solutions for small systems installing
treatment.
One commenter suggested that the costs for GAC seemed to be too
high. The figures used in the analysis could be two orders of magnitude
above the costs actually seen by the systems.
EPA Response 5-4
EPA agrees that its GAC cost estimates seem to be very high, as
compared to case studies (USEPA 1999h, AWWARF 1998b). EPA agrees with
others (e.g., AWWARF 1998a and b) that GAC will probably be cost-
effective for very small systems or in a point-of-entry mode. This
issue is addressed in the preamble (Section VIII.A) and GAC will be
included as a small systems compliance technology.
(d) Regionalization. Two commenters questioned a cost of $280,000
as the single cost for regionalization. Assuming $100/foot for an
interconnection, these costs would equate to an interconnection of 2800
feet which seems low. Systems are usually separated by more than one-
half mile. A range of costs may need to be considered rather than a
single number. Smaller systems will have smaller costs, while large
systems will have larger costs. Thus, the charge for regionalization
should vary by systems size. Also, EPA should clarify whether or not
regionalization charges include yearly operation and maintenance costs.
EPA Response 5-5
EPA agrees that the costs of regionalization would be expected to
change with water system size, but, as indicated in the assumptions
outlined in the February 26, 1999 HRRCA, EPA assumed that only very
small systems (those serving fewer than 500) would resort to
regionalization in response to the radon rule. Given that the proposed
rule involves a multi-media approach that greatly encourages small
systems to choose the AMCL of 4000 pCi/L in conjunction with a multi-
media mitigation program, EPA expects that very few systems would
choose regionalization as an option. EPA believes that the assumption
that 1 out of 100 small systems that choose the MCL option would
regionalize is conservative and would only be exercised if
regionalization were cost-competitive with other options, except under
very unusual circumstances. Since the estimate of $250,000 is much more
expensive than any other option modeled for those size categories, this
assumption supports the situation where small systems may be expected
to entertain this option, i.e., where regionalization does not involve
piping water over great distances. This figure is based on a simple
estimate using the cost of installed cast iron pipe at $44 per linear
foot (an average cost for several pipe relevant pipe diameters) from
the 1998 Means Plumbing Cost Data and applying 20 percent for fittings,
excavation, and other expenses to arrive at an estimate of $53 per
linear foot, or $280,000 per linear mile. Purchased water costs ($/
kgal) were assumed to equal the pre-regionalization costs of production
($/kgal), merely as a modeling convenience. In some cases, purchased
water costs may be higher, in
[[Page 59340]]
some cases lower. Although EPA does not have many case studies to
support this assumption, it does have information on a Wisconsin case
study in which a small water system (serving 375 persons) regionalized
to connect to a near-by city water supply in 1995, partly in response
to a radium violation. The capital costs for this regionalization case
study was $225,000. There were no reported operations costs associated
with the purchased water. EPA makes no claims that this case study is
typical, but rather that this is the best assumption that it could make
based on the available information. Since this is a minor part of the
over-all national costs and since a more extensive modeling of the
costs of regionalization would necessitate a much more detailed
modeling of the additional benefits of regionalization (which were not
included), this assumption is maintained in the Regulatory Impact
Assessment for this proposed rule.
One commenter also questioned the feasibility of regionalization
for many systems. There are very few locations where this is possible
and just hooking up to a larger supplier is not practical. Many have
systems that are not acceptable to a larger supplier and many larger
suppliers won't accept the liability involved in taking over the small
system.
EPA Response 5-6
Since most small systems are expected to adopt the AMCL/MMM option,
EPA's regionalization assumption (1 percent of the minority of small
systems that choose the MCL option) is consistent with this commenter's
concern. Nevertheless, administrative regionalization is often
feasible, in particular when this does not require new physical
connections, and may be an important element of the long term
compliance strategy for a number of systems.
(e) Pre-treatment to reduce iron/manganese levels. The majority of
the commenters disagreed with EPA's assumptions on the removal of Fe/
Mn. It was assumed that essentially all systems with high Fe/Mn levels
are likely to already be treating to remove or sequester these metals.
Therefore, costs of adding Fe/Mn treatment to radon removal were not
included in the February, 1999 HRRCA (64 FR 9560). Commenters suggested
that this is a poor cost assumption, in that there are many systems
above the secondary MCL for Fe/Mn that do not treat. Of those that
sequester, commenters suggested that existing treatment is ineffective
once Fe/Mn has been oxidized. Therefore, filtration as well as
disinfection would be required for that type of system at a significant
additional cost that needs to be considered when reviewing the HRRCA.
If Fe/Mn is present in the source water, removal treatment will be
necessary to prevent fouling of the radon removal system. Disposal for
the Fe/Mn residuals also presents a special problem with its associated
costs. One commenter noted that by not including the costs of Fe/Mn
removal, EPA is making a poor assumption and may be underestimating
costs.
EPA Response 5-7
EPA recognized that not quantifying the costs associated with the
control of dissolved iron and manganese (Fe/Mn) was potentially a poor
assumption, and indicated that this assumption would be revisited for
the Regulatory Impact Analysis supporting this proposed rule. However,
EPA also indicated that national costs and average per system costs
would probably not be significantly affected in addressing this issue.
While EPA's current modeling results support this conclusion, EPA has
included the costs of adding chemical stabilizers (which minimize Fe/Mn
precipitation and also provide for corrosion control in some cases) by
25 percent of small systems that treat and 15 percent of large systems
that treat. A more detailed discussion on the inclusion of Fe/Mn
treatment costs is provided in Section VIII of the preamble.
To further support its position on Fe/Mn control, EPA has also (1)
analyzed case studies of systems aerating, which include Fe/Mn control
measures for a small minority of the systems, (2) performed an analysis
of the co-occurrence of radon with Fe/Mn in ground water, and (3)
performed an uncertainty analysis on costs, which includes a simulation
of more expensive control measures for Fe/Mn. All of these results are
also discussed in Section VIII of the preamble.
(f) Post treatment-disinfection. Many commenters stated that EPA's
assumption that the majority of groundwater systems already disinfect
is false. Some commenters felt this is inconsistent with the Ground
Water Rule estimates. Commenters suggested that analyses supporting the
proposed groundwater rule estimate that only 50 percent of CWSs and
only 25 percent of NTNCWSs disinfect, while Table 5-2 of the HRRCA
suggests that the majority of water systems using groundwater already
disinfect and that 20 percent of all water systems serving 3,300 or
greater have aeration or disinfection in place.
EPA Response 5-8
The cited analyses supporting the Ground Water Rule (GWR) were
conducted using occurrence estimates at the level of individual entry
points at water systems. The February 1999 Radon HRRCA was conducted
using occurrence estimates at the level of water systems. The GWR and
radon analyses use the same data source for estimating their respective
disinfection-in-place baselines, the 1997 Community Water System Survey
(USEPA 1997a), the only source of information of this type that is
based on a survey that was designed to be statistically representative
of community water systems at the national level. The GWR used a
disinfection-in-place baseline for entry points and the radon HRRCA
used a disinfection-in-place baseline for water systems.
The most desirable level of analysis is at the entry point, but the
only nationally representative data source for radon, the National
Inorganics and Radionuclides Survey, was conducted at the water system
level (samples were taken at the tap), which provides no information
about radon occurrence at individual entry points within water systems.
Radon intrasystem (within system) occurrence variability studies were
not available for the analyses supporting the February 1999 radon
HRRCA. In the interim between publishing the radon HRRCA and today's
proposal, EPA has conducted radon intrasystem variability studies
(based on studies other than NIRS) and has used the results of this
study to estimate radon occurrence at the entry point level. The
current Regulatory Impact Analysis supporting the Radon rule was
conducted at the entry point level, consistent with the Ground Water
Rule.
EPA Response 5-9
The additional costs to which this commenter is referring, namely
the costs of storage for contact time, are included in the costs of the
clearwell, which are included in the costs of the aeration process. In
the scenarios in which disinfection is assumed, EPA does NOT assume
that the systems have a clearwell in place and does include the costs
of adding a clearwell for collection of water after aeration and for
five minutes of disinfection contact time, which EPA believes to be
sufficient for 4-log viral de-activation.
(g) Monitoring costs. One commenter expressed concerns regarding
EPA's calculation of monitoring costs. The commenter suggested that EPA
grossly underestimated the number of wells per
[[Page 59341]]
different water system size in Table 5.4 of the HRRCA (64 FR 9585),
page 9585 and in Appendix D of the HRRCA. As a result, monitoring costs
need to be recalculated by EPA.
EPA Response 5-10
See EPA Response 1-2 for EPA's approach to determining the number
of wells per system.
(h) Choice of treatment responses. As noted previously in Section
G, one commenter questioned whether chlorination would always be the
disinfection technology of choice, as well as EPA's assumption that
existing chlorination practices would not have to be augmented if
aeration were installed. Other commenters on cost issues questioned the
feasibility and practicability of some technologies on cost grounds.
EPA Response 5-11
EPA assumed that chlorination would be the ``typical'' disinfection
technology chosen to model the ``average treatment costs'' (or
``central tendency costs''). There is no way to know beforehand exactly
how the universe of water systems will behave in response to a given
situation, so EPA believes that the best way to model national
compliance costs is to estimate these central tendency costs, then to
use statistical tools to capture the fact that ``real world costs''
will spread around the central tendency costs, rather than being
equivalent to them. By estimating the central tendency costs and using
statistical uncertainty to capture ``real world'' variability
(including variability in disinfection costs), EPA believes that this
modeling technique allows for the fact that real systems will behave in
a variety of ways, including things like choosing different
disinfection technologies.
(i) Site and system costs. A number of issues were raised
concerning site and system cost estimates. Several commenters suggested
that the HRRCA severely underestimated the number of sites per system,
citing the difference between the CWSS data and HRRCA assumptions.
Several commenters noted that the numbers of sources per system in
Table 5-4 of the HRRCA for systems serving 10,001--50,000 were too low.
One commenter maintained that the number of sources per system could
have a significant impact on national treatment costs.
EPA Response 5-12
EPA agrees that the distribution of the number of sites per system
was underestimated and has revised its estimate to be consistent with
the CWSS. However, it should be noted that while the distribution of
the sites per system actually does have an impact on national treatment
costs, this impact is significantly mitigated by the fact that the flow
per well being treated decreases proportionally as the estimated number
of wells per system increases.
(j) Aggregated national costs. Several commenters agreed that the
national average costs masked significant impacts on small systems.
When small systems are considered, the financial impact is large; in
some cases, water bills could double or triple. Providing individual
system costs is critical so that utilities can explain to their
customers the specific costs and benefits for that specific system.
EPA Response 5-13
EPA estimates household impacts for small systems that install
treatment (per household costs) by estimating the costs that small
systems would face (per system costs), then spreading these costs over
the customer base (population served). As demonstrated in the HRRCA,
household costs for small systems are expected to be many times higher
for very small systems than for larger systems. In listing small
systems compliance technologies for radon, EPA estimated the impacts on
small systems by estimating the per system costs and the per household
costs and comparing them to affordability criteria, as described in
this notice and in the references cited. However, it should also be
noted that the vast majority of small systems are expected to comply
with the AMCL/MMM option, rather than the MCL option. Under these
circumstances, less than 1 percent of small systems would have to take
measures to reduce radon levels in their drinking water.
(k) Costs to CWSs. Small systems will bear a significant percentage
of the costs for implementing a radon MCL, but will only accrue a small
proportion of the benefits. At the 300 pCi/L, the two categories of
smallest systems combined would receive 5.6 percent of the benefits at
this level, but would pay 42 percent of the total costs. Several
commenters indicated that the benefit-cost ratio for small systems was
thus highly unfavorable.
EPA Response 5-14
EPA recognizes that small systems experience similar benefits per
customer as large systems, but, due to economies of scale (higher
treatment costs per gallon treated), experience much higher costs per
customer compared to large systems. This, of course, leads to higher
costs at the same level of benefits. However, EPA has also recognized
that radon is a multi-media problem in which most of the risk is
presented from sources other than drinking water and has addressed this
fact by designating the AMCL/MMM option as the preferred option for
small systems. This will greatly lower the per customer costs faced by
small systems and may lead to greater total benefits that accrue to
small systems.
(l) Costs to consumers/households. One commenter thought that the
household consumption presented in the HRRCA (83,000 gal/year) is too
low. This is an understatement because treatment would be required for
all water produced, not just water consumed by households.
EPA Response 5-15
EPA does not assume that per system costs are based only on
residential water use and so does not miscalculate water prices in the
way described by the commenter. To determine the price of water, EPA
calculates per system costs based on both residential and non-
residential consumers (which is the main reason EPA calculates costs
for privately-owned and publically-owned separately, i.e., because they
have different ratios of residential to non-residential consumption).
These per system costs determine the costs per gallon treated (not per
gallon consumed) to determine the water price. The water price may then
be used in conjunction with the household consumption to estimate the
water bills faced by households, since they do pay by the gallon
consumed (and not by the gallon treated).
(m) Application of radon related costs to other rules. Several
commenters addressed the need to include the cumulative impact of
regulations in the RIA. The incremental costs of the regulations for
radon, arsenic, and groundwater systems could substantially change the
affordability analysis for small systems. Thus, treatment decisions
need to be made with an understanding of all the requirements that must
be met so that treatment systems can be designed to meet all
requirements. One commenter suggested a multi-rule cost and benefit
analysis to capture the true costs incurred by these systems.
EPA Response 5-16
The cumulative effects of rules are captured in EPA's
``affordability criteria'', which are described in the publicly
available 1998 EPA document, ``National-Level Affordability Criteria
Under the 1996 Amendments to the Safe
[[Page 59342]]
Drinking Water Act'' (USEPA 1998e). These small system affordability
criteria take into account how much consumers are currently paying for
typical water bills. Since the upcoming regulations will affect these
amounts, the cumulative effect of the costs of the rules will be
explicitly considered in the affordability determinations for small
systems as new rules are issued. EPA recognizes that its method of
basing affordability determinations on average costs does not address
the situation of systems that have significantly above average costs
because they must treat for a number of contaminants simultaneously.
EPA believes this approach is consistent with the requirements of SDWA
for identifying affordable small system technologies and notes that
other SDWA mechanisms may be used to address situations where systems
incur considerably higher costs.
6. Cost and Benefit Results
The main concern of many of the comments regarding this section
suggested that the costs of controlling radon in drinking water far
outweighed possible benefits, especially for small systems. Controlling
indoor air radon was identified as a better use of regulatory and
economic resources by several commenters. Commenters also had concerns
regarding how national total costs, benefits, and economic impacts were
calculated, and regarding the uncertainties in costs and benefits
estimates.
(a) Overview of analytical approach. Many commenters indicated that
the cost-benefit analysis was skewed toward overestimating benefits,
and/or omitted important cost elements. One concern shared by many of
these commenters was that the cost-benefit calculations were biased
because mitigation costs, but not health benefits, were discounted. A
commenter also indicated that too many assumptions had been used to
derive cost and benefit estimates.
EPA Response 6-1
The radon cost benefit analysis was performed according to EPA
guidelines, in an attempt to fairly portray both costs and benefits,
and not leave out important categories of either costs or benefits.
Annual mitigation costs are compared to annual benefits for the
cost benefit comparisons. Annual mitigation costs consist of annualized
capital costs plus yearly operating costs. Annualized costs are
computed under the assumption that capital expenditure are made up
front, with borrowed funds, and the payments are then annualized over a
period of twenty years. Changes in the rate of interest used in the
annualization process will change the annual cost, just like a mortgage
will change with different rates of interest. Adding yearly operating
costs for one year to annualized capital costs for one year gives the
total annual cost for the year. The issue of discounting of benefits is
discussed in Section XIII.D.
In any modeling process, assumptions must be made. To model costs
and benefits, assumptions about those costs and benefits must be made.
The number of assumptions needed depends on the complexity of the
problem addressed, and the time and information available to address
it. We would be interested in information that might inform our
modeling, particularly addressing improvements that could be made to
specific assumptions.
(b) MCL decision-making criteria. A commenter requested that EPA
define explicit decision-making criteria for setting MCL levels, to
assure that the net benefit to society is positive.
Another commenter indicated that, because drinking water radon
accounts for a small portion of total risks, EPA should consider the
relative costs and benefits of mitigation on a case-by-case basis at
individual systems before making regulatory decisions. A commenter
suggested that if the latency of cancer risk reduction and benefits
were discounted properly, the national cost-benefit ratios for radon
mitigation would be between 5:1 and 9:1. They stated that EPA should
not promulgate a rule with net negative benefits, especially in light
of the large economic impacts on small systems.
A commenter indicated that the cost-benefit ratios in Table 6-13 of
the HRRCA imply that regulation of radon in ground water is not
justified. They point out that systems serving 25-3,300 people incur at
least 56 percent of the costs and generate at most 21 percent of the
total benefits at all MCLs. They say that justifying radon control in
drinking water by adding in the benefits of MMM programs is not
justified. Another commenter also maintained that the small, localized
benefits of controlling radon exposures do not come near to justifying
the costs of mitigation.
One commenter said that the decision to set an MCL must take into
account the level of uncertainty in cost and benefit estimates. Another
commenter suggested that the Agency undertake a quantitative
uncertainty analysis of the cost and benefit estimates. Two commenters
said that the closeness of the cost and benefit estimates should be
considered in setting a regulatory level; if uncertainty is large, a
less stringent MCL would be justified.
EPA Response 6-2
EPA has included a detailed discussion on its decision-making
criteria for setting the MCL for radon in drinking water in the
preamble for the proposed rulemaking (see Section VII.D).
(c) National costs of radon mitigation. Two commenters indicated
that the national cost estimates obscured the high costs that would be
borne by individual systems. One commenter indicated that radon
variability in individual wells increases the uncertainty in the cost
estimates. Another commenter said that cost estimates should include
the costs of more frequent lead and copper exceedences brought about by
increased aeration. Other comments on specific cost elements were
summarized in Section 5. One commenter requested that EPA regionally
disaggregate cost and benefit estimates because of structural and
operational differences among water systems. Another commenter
suggested that EPA should conduct a more comprehensive analysis of
costs and benefits, including cost elements not currently addressed,
such as waste management.
EPA Response 6-3
The national costs include an uncertainty analysis which captures
the regional spread in treatment costs. In addition, EPA has estimated
total national costs by assuming that most systems will face ``typical
costs'', but that some will face ``high side'' and some ``low side''
treatment costs. These ``high side'' and ``low side'' cost differences
are largely based on regional considerations, like the costs of land,
structure, and permitting.
(d) Incremental costs and benefits. One commenter indicated that
the incremental costs and benefits of the various MCL options should be
presented in the HRRCA. They question the affordability of radon
mitigation for small systems.
EPA Response 6-4
EPA has provided an analysis of the incremental costs and benefits
of each MCL option in the HRRCA. See Table 6-7, Estimates of the Annual
Incremental Costs and Benefits of Reducing Radon in Drinking Water, in
the February 1999 HRRCA.
(e) Costs to community water systems. One commenter said that a
more accurate picture of costs and impacts (inclusive of State and
local costs) would be needed to make a reasonable
[[Page 59343]]
risk management decision. Another commenter suggested that EPA should
consider the cumulative costs of all drinking water regulations on
drinking water systems.
EPA Response 6-5
See EPA Response 5-14 for EPA's approach to determining the costs
to CWSs. Administrative costs to States were not included in the
February 1999 HRRCA, but have been added in the RIA for the proposed
rule.
(f) Costs and impacts on households. One commenter asked that EPA
explain how it determined what was an ``acceptable'' percentage of
household income that would go to radon mitigation. Another commenter
indicated that household costs should be compared to benefits at the
local, rather than national, level, because benefits and costs are
realized locally. A commenter indicated the median household incomes
for households served by different system sizes are not shown; they
also suggested that household costs as a percentage of income were
underestimated in Table 6-11 of the HRRCA. One commenter said that
expressing household impacts as a proportion of annual income
trivializes it and that costs could more meaningfully be compared to
other types of household expenses (i.e., food, rent). Several
commenters also noted the significant impact the costs could have on
customer water bills for small systems.
EPA Response 6-6
See EPA Response 5-15 for EPA's approach to determining the costs
to households.
(g) Summary of costs and benefits. Comments from one organization
regarding the cost-benefit comparison for radon mitigation were typical
of those received from other sources. They cited the NRC/NAS report as
indicating that only two percent of population risk came from drinking
water and questioned whether the high costs of the rule could justify
the small benefits obtained. They said that the cost-benefit comparison
did not justify regulating radon in ground water, especially in small
systems, where costs were highest and benefits lowest. Another
commenter also pointed out that it would be more cost-effective to
regulate radon in indoor air than in drinking water and further
maintained that spending resources to mitigate radon in water could
actually result in reduced public health protection. They point out
that the cost-benefit ratios for the smallest systems range from 20:1
to 50:1, and suggest that these ratios, rather than the greater
aggregate costs to large systems, should be persuasive in regulatory
decision making. Other commenters suggested the high cost-benefit
ratios did not justify the regulation of small systems.
EPA Response 6-7
The 1996 Safe Drinking Water Act Amendments require EPA to propose
a regulation for radon in drinking water by August 1999. The options
for small systems, proposed for public comment in this rulemaking,
represents EPA's efforts to address stakeholder comments concerning
small systems.
7. Multimedia Mitigation Programs
(a) Multimedia programs. Two commenters indicated that setting the
AMCL at 4,000 pCi/L was justifiable. They suggested that EPA should
utilize on MMM approach as the primary tool for reducing radon risks,
and not use the SDWA to force the States to develop MMM programs.
Several commenters noted that the MCL EPA selects should be
justifiable on cost-benefit grounds, with the MMM program serving as a
supplemental program to allow States to achieve greater risk reduction
at less cost. Another commenter suggested the multimedia approach
allowed under the 1996 amendments to the SDWA should not be used with
regard to radon-222 in water.
EPA Response 7-1
The requirement for implementation of an EPA-approved MMM program
in conjunction with State adoption of the AMCL is consistent with the
statutory framework outlined by Congress in the SDWA provision on
radon. As proposed, States may choose either to adopt the MCL or the
AMCL and an MMM program. EPA recommends that small systems comply with
an AMCL of 4,000 pCi/L and implement a MMM program. See section VII.D
for background on the selection of the MCL and AMCL.
Two commenters believe the radon regulation may result in
litigation against water utilities, local, and State governments if
systems comply with the AMCL rather than the MCL. As a result, some
water utilities could choose to comply with the more stringent MCL
rather than face potential litigation for meeting a ``less stringent
standard,'' regardless of the increased public health protection.
According to one commenter, problems will arise when both the AMCL and
the MCL are required to appear on the annual Consumer Confidence
Report. The public will view the AMCL as an attempt by the water
industry to get around the MCL. This will leave the water utility
vulnerable to toxic tort lawsuits. Because of these problems, the
concept of an MMM program/AMCL is not as attractive as it once
appeared.
EPA Response 7-2
EPA is aware of this concern and the risk communication challenges
of two regulatory limits for radon in drinking water. However, the SDWA
framework requires EPA to set an alternative maximum contaminant limit
for radon if the proposed MCL is more stringent than the level of radon
in outdoor air. It is important to recognize that in State primacy
applications for oversight and enforcement of the drinking water
program, States choosing the MMM approach will be adopting 4,000 pCi/L
as their MCL. In addition, as part of the proposed rule, EPA will be
amending the Consumer Confidence Reporting Rule to reflect the proposed
regulation for radon. Under Sec. 141.153 of the proposed radon rule, a
system operating under an approved multimedia mitigation program and
subject to an Alternative MCL (AMCL) for radon must report the AMCL
instead of the MCL whenever reporting on the MCL is required.
Another commenter questioned the need for regulating radon in water
below 3,000 pCi/L, and maintained that there is no conceivable reason
to regulate it at 100 pCi/L, with or without an MMM program.
EPA Response 7-3
See EPA Response 6-2 for EPA's decision criteria for setting an
MCL.
(b) Implementation scenarios evaluated. One commenter feels that a
``desk top review'' of States likely to adopt an MMM program would give
more useful estimates of MMM acceptance than the HRRCA assumptions of
zero, 50 percent, and 100 percent adoption of MMM programs. This
commenter felt that for an MMM program to be productive, two things are
necessary: (1) relatively high radon concentration in water and (2)
relatively high radon in indoor air.
EPA Response 7-4
For the purposes of the HRRCA, EPA made these assumptions as a
straight forward approach for assessing overall cost implications of
MMM. States are not required to make their determinations on whether to
adopt the MMM approach until after the rule is final in August 2000.
Therefore, EPA did not have this information available when developing
the HRRCA, nor does EPA have this information at this time. However,
discussions with many State
[[Page 59344]]
drinking water and radon program staff suggest that many States are
seriously considering the MMM approach.
EPA expects that MMM programs will be able to achieve indoor radon
risk reduction even in areas of low radon potential. It is important to
keep in mind that the only way to know if a house has elevated indoor
radon levels is to test it. Many homes in low radon potential areas
have been found with levels well above EPA's action level of 4 pCi/L,
often next door to houses with very low levels. EPA estimates that
about 6 million homes in the U.S. of the 83 million homes that should
test are at or above 4 pCi/L. To date only about 11 million homes have
been tested. In addition, EPA is not requiring State MMM program plans
to precisely quantify equivalency in risk reduction between radon in
drinking water and radon in indoor air.
(c) Multimedia mitigation cost and benefit assumptions. Two
commenters indicated that, even if it is not known how the MMM programs
will be funded, the costs of administering such programs should be
included in the HRRCA. Several commenters expressed concerns regarding
the estimated cost of $700,000 per fatal cancer averted. One commenter
felt that using this value is far too optimistic, indicating that the
cost of radon risk reduction under State-mandated MMM programs will
significantly exceed present costs under the voluntary system. To get
the greatest risk reductions at the lowest costs, MMM program should
focus on the houses with the highest radon concentrations. Another
commenter recommended that EPA develop an MMM program that is better
than the existing voluntary programs and further reduces the cost per
fatal cancer avoided. The commenter also requested that EPA supply
background information supporting use of this single MMM program cost
estimate.
EPA Response 7-5
EPA is required under the UMRA to assess the costs to States of
implementing and administering both the MCL and the MMM/AMCL. EPA has
addressed these costs in the preamble of the rule.
EPA believes that the criteria for EPA approval of State MMM
program plans will augment and build on existing State indoor radon
programs and will result in an increased level of risk reduction.
As part of developing the 1992 ``A Citizen's Guide to Radon,'' EPA
analyzed the risk reductions and costs of various radon testing and
mitigation options (USEPA 1992b). Based on these analyses, a point
estimate of the average cost per life saved of the current national
voluntary radon program was used as the basis for the cost estimate of
risk reduction for the MMM option. EPA had previously estimated that
the average cost per fatal lung cancer avoided from testing all
existing homes in the U.S. and mitigation of all those homes at or
above EPA's voluntary action level of 4 pCi./L is approximately
$700,000. This value was originally estimated by EPA in 1991. Since
that time there has been an equivalent offset between a decrease in
testing and mitigation costs since 1992 and the expected increase due
to inflation in the years 1992-1997.
One commenter stated that experiences in Massachusetts showed that
the costs of incorporating passive radon resistant construction
techniques is about the same as current prices for marginal quality
(active) radon mitigation in existing buildings, and disputed the HRRCA
statement that passive techniques are much less expensive. The
commenter supported the NAS findings that the effectiveness of these
techniques in normal construction practice is uncertain.
EPA Response 7-6
Builders have reported costs as low as $100 to install radon
resistant new construction features which is significantly less than
the $350--$500 that was derived in EPA's cost-effectiveness analysis of
the radon model standards. The cost of materials alone for the passive
system will always be less than the cost for an active system which
includes the cost of a fan. In many areas, the majority of the features
for radon-resistant new construction are already required by code or
are common building practice, such as an aggregate layer, ``poly''
sheeting, and sealing and other weatherization techniques. The only
additional cost is associated with the vent stack consisting of PVC
pipe and fittings. In those areas where gravel is not commonly used,
builders can use a drain tile loop or other alternative less costly
than gravel to facilitate communication under the slab. EPA estimates
that the cost to mitigate an existing home ranges from $800 to $2,500
with an average cost of $1,200.
(d) Annual costs and benefits of MMM program implementation.
Several concerns were raised regarding the costs and benefits
associated with MMM program implementation. One commenter suggested
that the MMM program description in the HRRCA provides essentially no
guidance on the point from which additional risk reduction due to MMM
will be measured.
EPA Response 7-7
The HRRCA was not intended to include a discussion and description
of the criteria for EPA approval of State MMM programs. Rather,
proposed criteria are presented in this proposed rule. EPA's proposed
criteria do not entail a determination by the State of the level of
indoor radon risk reduction that has already occurred (``baseline'') as
the basis for determining how much more risk reduction needs to take
place. Rather States, with public participation, are required to set
goals that reflect State and local needs and concerns.
Another commenter states that EPA has underestimated the benefits
of an MMM program. The HRRCA registers only the benefits gained in
relation to water being treated to the MCL. However, according to EPA's
figures, MMM benefits are expected to be much higher than those
achieved by mitigating water alone.
EPA Response 7-8
EPA anticipates that MMM programs will result in sufficient risk
reduction to achieve ``equal or greater'' risk reduction. A complete
discussion on why MMM is expected to achieve equal or greater risk
reduction is shown in Section VI.B of today's preamble. For the
purposes of the HRRCA analyses, EPA made the conservative assumption
that the level of risk reduction would at least be ``equal'' to that
achieved by universal compliance with the MCL.
8. Other Key Comments
(a) Omission of non-transient non-community water systems
(NTNCWSs). Eleven commenters criticized EPA's failure to include
NTNCWSs in the HRRCA. Three commenters indicate that failure to include
NTNCWSs grossly underestimates costs of radon mitigation. Another
commenter also suggests that NTNCWSs should be included in the HRRCA,
to provide a better picture of both costs and benefits. Two commenters
would also like NTNCWSs included because impacts on these systems are
likely to be high. Other commenters maintain that excluding NTNCWSs
skews benefit-cost analyses in favor of regulation. Another commenter
indicates that NTNCWSs, because of the type of wells and aquifers that
they draw from, will be most affected by a radon rule.
EPA Response 8-1
Partly as a result of concerns raised by commenters, and partly as
a result of its own preliminary analysis of exposure and risk, EPA is
not proposing that NTNCWSs be covered by this rule. A more complete
discussion of this issue
[[Page 59345]]
is included in the preamble for the proposed rule. EPA has conducted a
preliminary analysis on exposure and risks to NTNCWSs and is asking for
public comment on this preliminary analysis and on the proposed
exclusion of NTNCWSs. An analysis of the potential benefits and costs
of radon in drinking water for NTNCWSs is included in the docket for
this proposed rulemaking. (USEPA 1999m)
XIV. Administrative Requirements
A. Executive Order 12866: Regulatory Planning and Review
Under Executive Order 12866, ``Regulatory Planning and Review'' (58
FR 51,735 (October 4, 1993)), the Agency must determine whether the
regulatory action is ``significant'' and therefore subject to OMB
review and the requirements of the Executive Order. The Order defines
``significant regulatory action'' as one that is likely to result in a
rule that may:
(1) have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
(2) create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
(3) materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
Pursuant to the terms of E.O. 12866, it has been determined that
this rule is a ``significant regulatory action''. As such, this action
was submitted to OMB for review. Changes made in the proposal in
response to OMB suggestions or recommendations will be documented in
the public record.
B. Regulatory Flexibility Act (RFA)
1. Today's Proposed Rule
Under the Regulatory Flexibility Act (RFA), 5 U.S.C. 601 et seq.,
as amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA), EPA generally is required to conduct a regulatory flexibility
analysis describing the impact of the regulatory action on small
entities as part of rulemaking. Today's proposed rule may have
significant economic impact on a substantial number of small entities
and EPA has prepared an Initial Regulatory Flexibility Analysis (IRFA).
In addition, when preparing an IRFA, EPA must convene a Small Business
Advocacy Review (SBAR) Panel. A discussion of the Panel's
recommendations and EPA's response to their recommendations is shown in
Section 6.
2. Use of Alternative Small Entity Definition
The EPA is proposing that small CWS serving 10,000 people or less
must comply with the AMCL, and implement a MMM program (if there is no
state MMM program). This is the cut-off level specified by Congress in
the 1996 amendments to the Safe Drinking Water Act for small system
flexibility provisions. Because this definition does not correspond to
the definitions of ``small'' for small businesses, governments, and
non-profit organizations previously established under the RFA, EPA
requested comment on an alternative definition of ``small entity'' in
the Preamble to the proposed Consumer Confidence Report (CCR)
regulation (63 FR 7620, February 13, 1998). Comments showed that
stakeholders support the proposed alternative definition. EPA also
consulted with the SBA Office of Advocacy on the definition as it
relates to small business analysis. In the preamble to the final CCR
regulation (63 FR 4511, August 19, 1998), EPA stated its intent to
establish this alternative definition for regulatory flexibility
assessments under the RFA for all drinking water regulations and has
thus used it for this radon in drinking water rulemaking. Further
information supporting this certification is available in the public
docket for this rule.
3. Background and Analysis
The RFA requires EPA to address the following when completing an
IRFA: (1) describe the reasons why action by the Agency is being
considered; (2) state succinctly the objectives of, and legal basis
for, the proposed rule; (3) describe, and where feasible, estimate the
number of small entities to which the proposed rule will apply; (4)
describe the projected reporting, record keeping, and other compliance
requirements of the rule, including an estimate of the classes of small
entities that will be subject to the requirements and the type of
professional skills necessary for preparation of reports or records;
(5) identify, to the extent practicable, all relevant Federal rules
that may duplicate, overlap, or conflict with the proposed rule; and
(6) describe any significant alternatives to the proposed rule that
accomplish the stated objectives of applicable statutes while
minimizing any significant economic impact of the proposed rule on
small entities. EPA has considered and addressed all of the previously
described requirements. The following is a summary of the IRFA.
The first and second requirements are discussed in Section II of
this Preamble. The third, fourth, and sixth requirements are summarized
as follows. The fifth requirement is discussed under Section VIII.A.2
of this Preamble in a subsection addressing potential interactions
between the radon rule and upcoming and existing rules affecting ground
water systems.
4. Number of Small Entities Affected
EPA estimates that 40,863 ground water systems are potentially
affected by the proposed radon rule, with 96 percent of these systems
serving less than 10,000 persons. Of the 39,420 small systems
potentially affected, EPA estimates that 1,761 (4.4 percent) small
systems will have to modify treatment (install treatment technology) to
comply with the AMCL. The proposed rule recommends that small systems
meet the 4,000 pCi/L AMCL and implement a multimedia mitigation (MMM)
program if their State does not implement a MMM program. Small systems
may also choose to comply with the MCL rather than implement an MMM
program. As Table XIV.1 indicates, water mitigation administration
costs for small systems remain the same under any State MMM program
adoption scenario. However, small systems located in States that do not
implement a MMM program must develop and implement their own MMM
program for the population they serve (unless they choose to comply
with the MCL), thus increasing their costs. Additional MMM
implementation scenarios have been analyzed in the RIA (USEPA 1999f)
which is included in the docket for this proposed rulemaking.
[[Page 59346]]
Table XIV.1.--Annual Water Mitigation and MMM Program Costs to Small
Systems
[$Millions, 1997]
------------------------------------------------------------------------
100% of states 50% of states
Cost description adopt MMM adopt MMM
------------------------------------------------------------------------
Water Mitigation Costs \1\
Total Capital Costs................. 118.5 194.1
Total Annual Costs \2\.............. 31.3 43.2
Water Mitigation Administration Costs... 5.8 5.8
Multimedia Mitigation Program Costs \3\. 0 43.3
Total Small System Costs per Year....... 37.1 92.4
------------------------------------------------------------------------
Notes:
\1\ Costs to small systems to mitigate water to the AMCL of 4,000 pCi/L.
\2\ Includes annual capital costs, monitoring costs, and operation and
maintenance costs.
\3\ Does not include the costs of testing and mitigating homes.
5. Proposed Rule Reporting Requirements for Small Systems
The proposed radon rule requires small systems to maintain records
and to report radon concentration levels at point-of-entry to the water
system's distribution system. Small systems are also required to
provide radon information in the Consumer Confidence Report, and if the
system is implementing its own MMM program, reports on progress to the
goals outlined in the system's MMM program plan. Radon monitoring and
reporting for water mitigation will be required on a quarterly basis
for at least one year, but thereafter the frequency may be reduced to
annually or once every three years depending on the level of radon
present (see Section VIII.E). Other existing information and reporting
requirements, such as Consumer Confidence Reports and (proposed) public
notification requirements, will be marginally expanded to encompass
radon along with other contaminants (see Section X). As is the case for
other contaminants, required information on system radon levels must be
provided by affected systems and is not considered to be confidential.
The professional skills necessary for preparing the reports are the
same skill level required by small systems for current reporting and
monitoring requirements.
The classes of small entities that are subject to the proposed
radon rule include public groundwater systems serving less than 10,000
people. Small systems are further classified into very very small
systems (serving 25-500 persons), very small systems (serving 501-3,300
persons, and small systems (serving 3,301-10,000 persons).
6. Significant Regulatory Alternatives and SBAR Panel Recommendations
In response to the SBAR Panel's recommendations and other small
entity concerns, EPA has included several requirements to help reduce
the impacts of the proposed radon rule on small entities. These
requirements include: (1) Recommendation of small system compliance
with the MMM/AMCL option; (2) less routine monitoring; (3) State
granting of waivers to ground water systems to reduce monitoring
frequency; and (4) encouraging and providing information about the use
of low maintenance treatment technologies. A more complete discussion
of the SBAR Panel recommendations and EPA's responses follow here. EPA
also believes small systems can in some cases reduce their economic
burden by a variety of means, including using the State revolving fund
loans to offset compliance costs. In the development of this proposed
rulemaking, EPA considered several regulatory alternatives to the
proposed requirements for small systems. The proposal includes the
regulatory expectation that they comply with the AMCL of 4,000 pCi/L
and be associated with either a state or local MM program. EPA believes
that this option will provide equivalent or greater health protection
while reducing economic burdens to small systems. For a more detailed
description of the alternatives considered in the development of the
proposed rule see the RIA (USEPA 1999f) or the discussion of regulatory
alternatives in Section XIV.C (Unfunded Mandates Reform Act).
In addition to being summarized here, the public docket for this
proposed rulemaking includes the SBAR Panel's report on the proposed
radon regulation, which outlines background information on the proposed
radon rule and the types of small entities that may be subject to the
proposed rule; a summary of EPA's outreach activities; and the comments
and recommendations of the small entity representatives (SERs) and the
Panel.
(a) Consultations. Consistent with the requirements of the RFA as
amended by SBREFA, EPA has conducted outreach directly to
representatives of small entities that may be affected by the proposed
rule. Anticipating the need to convene a SBAR Panel under Section 609
of the RFA/SBREFA, in consultation with the Small Business
Administration (SBA), EPA identified 23 representatives of small
entities that were most likely to be subject to the proposal. In April,
1998, EPA prepared an outreach document on the radon rule titled
``Information for Small Entity Representatives Regarding the Radon in
Drinking Water Rule'' (USEPA 1998b). EPA distributed this document to
the small entity representatives (SERs), as well as stakeholder meeting
discussion documents and the executive summary of the February 1994
document ``Report to the United States Congress on Radon in Drinking
Water: Multimedia Risk and Cost Assessment of Radon'' (EPA 1994a).
On May 11, 1998, EPA held a small entity conference call from
Washington DC to provide a forum for small entity input on key issues
related to the planned proposal of the radon in drinking water rule.
These issues included: (1) Issues related to the rule development, such
as radon health risks, occurrence of radon in drinking water, treatment
technologies, analytical methods, and monitoring; and (2) issues
related to the development and implementation of the multimedia
mitigation program guidelines. Thirty people participated in the
conference call, including 13 SERs from small water systems from
Arizona, California, Nebraska, New Hampshire, Utah, Washington,
Alabama, Michigan, Wyoming, and New Jersey.
Efforts to identify and incorporate small entity concerns into this
rulemaking culminated with the convening of a SBAR Panel on July 9,
1998, pursuant to Section 609 of RFA/SBREFA. The four person Panel was
headed by EPA's Small Business Advocacy Chairperson and included the
Director of the Standards and Risk Management Division within EPA's
[[Page 59347]]
Office of Ground Water and Drinking Water, the Administrator of the
Office of Information and Regulatory Affairs with the Office of
Management and Budget, and the Chief Counsel for Advocacy of the SBA.
For a 60-day period starting on the convening date, the Panel reviewed
technical background information related to this rulemaking, reviewed
comments provided by the SERs, and met on several occasions. The Panel
also conducted its own outreach to the SERs and held a conference call
on August 10, 1998 with the SERs to identify issues and explore
alternative approaches for accomplishing environmental protection goals
while minimizing impacts to small entities. Details of the Panel
process, along with summaries of the conference calls with the SERs and
the Panel's findings and recommendations, are presented in the
September 1998 document ``Final Report of the SBREFA Small Business
Advocacy Review Panel on EPA's Planned Proposed Rule for National
Primary Drinking Regulation: Radon'' (USEPA 1998c).
(b) Recommendations and Actions.--Today's notice incorporates all
of the recommendations on which the Panel reached consensus. In
particular, the Panel made a number of recommendations regarding the
MMM program guidelines, including that the guidelines be user-friendly
and flexible and provide a viable and realistic alternative to meeting
the MCL, for both States and CWSs. The Panel also agreed that provision
of information to the public and equity are important considerations in
the design of an MMM program.
In response to the Panel's recommendations and concerns heard from
other stakeholders, EPA has developed specific criteria that MMM
programs must meet to be approved by EPA. EPA believes these criteria
are simple and straightforward and provide the flexibility States and
public water systems need to develop programs to meet their different
needs and concerns. The criteria permit States, with public
participation and input, to determine their own prospective indoor
radon risk reduction goals and to design the program strategies they
determine are needed to achieve these goals. The criteria build on the
existing framework of State indoor radon programs that are already
working to get indoor radon risk reduction. EPA also believes that
equity issues can be most effectively discussed and resolved with the
public's participation and involvement in development of goals and
strategies for an MMM program. Providing customers of public water
systems with information about the health risks of radon and on the
AMCL and MMM program option will help to promote understanding of the
significant public health risks from radon in indoor air and help the
public to make informed choices. Section VI of this Preamble discusses
the MMM program in greater detail.
Following is a summary of the other Panel recommendations and EPA's
response to these recommendations, by subject area:
Occurrence: The Panel recommended that EPA continue to refine its
estimates of the number of affected wells. The occurrence section of
the preamble contains an expanded description in regard to how EPA
refined the estimates of the number of affected water supply wells (See
Section XI.C ``EPA's Most Recent Studies of Radon Levels in Ground
Water'').
Water Treatment: The Panel recommended the following: provide clear
guidance for when granular activated carbon (GAC) treatment may be
appropriate as a central or point-of-entry unit treatment technology;
consider and include in its regulatory cost estimates, to the extent
possible, the complete burden and benefits; and carefully consider
effects of radon-off- gassing from aeration towers and potential
permitting requirements in developing regulations or guidance related
to aeration.
In response to these recommendations, the treatment section of the
preamble contains an expanded description regarding conditions under
which granular activated carbon (GAC) treatment may be appropriate as a
central or point-of-entry unit treatment technology (See Section
VIII.A.3 ``Centralized GAC and Point-of-entry GAC''); the RIA and the
treatment sections of the preamble describe the components which
contribute to the regulatory economic analysis (See Section VIII.A.2
``Treatment Costs: BAT, Small Systems Compliance Technologies, and
Other Treatment''); high-end treatment cost estimates have been revised
to include scenarios where air-permitting costs are much higher than
typical cases (see Sections VIII.A.2 ``Treatment Cost Assumptions and
Methodology'' and ``Comparison of Modeled Costs with Real Costs from
Case Studies''); and information and rationale has been added to
support EPA's belief that permitting requirements from off-gassing from
aeration towers will not preclude installation of aeration treatment
(see Section VIII.A.3 ``Evaluation of Radon Off-Gas Emissions Risks'').
In addition, the Panel recommended that EPA fully consider the
relationship of the Radon in Drinking Water Rule with other rules
affecting the same small entities. In response, the treatment section
of the preamble, the Treatment and Cost Document, and the RIA have been
expanded to discuss the relationship of treatment for radon with other
drinking water rules including the Ground Water Rule, Lead and Copper
Rule, and the Disinfection By-Products Rules (see Section VIII.A.2
``Potential Interactions Between the Radon Rule and Upcoming and
Existing Rules Affecting Ground Water Systems'').
Analytical Methods and Monitoring: The Panel recommended the
following: fully consider the availability and capacity of certified
laboratories for radon analysis and consider the costs of monitoring;
consider applying the VOCs sampling method to radon to reduce the need
for additional training; reduce the frequency of monitoring after
initial determination of compliance and consider providing waivers from
monitoring requirements when a system is not at risk of exceeding the
MCL; and develop monitoring requirements that are simple and easy to
interpret to facilitate compliance by small systems.
In response, the analytical methods section of the preamble
includes discussion of the availability and capacity of certified
laboratories for radon analysis (see Section VIII.C ``Laboratory
Capacity--Practical Availability of the Methods''); and a clarification
that the radon sampling method is the same as for the volatile organic
carbons sampling method (see Section VIII.B.2 ``Sampling Collection,
Handling and Preservation''). The RIA and the preamble include more
detailed discussion of regulatory costs estimates including the
monitoring costs estimated (see Section VIII.B.2 ``Cost of Performing
Analysis''). The monitoring section proposed rule provides for a
reduced monitoring frequency to once every three years if the average
of four quarterly samples is less than 1/2 MCL/AMCL, provided that no
sample exceeds the MCL/AMCL (see Section VIII.E.4 ``Increased/decreased
monitoring requirements'' and Section 141.28(b) of the proposed rule).
Section VIII.E.5 ``Grandfathering of Data'' and Section 141.28(b) of
the proposed rule describes the allowance of grandfathered data, i.e.,
data collected after proposal of the rule, that meet specified
requirements. Section VIII.E.4 ``Increased/decreased monitoring
requirements'' of this Preamble discusses the allowance for States to
grant waivers to ground water systems to reduce the frequency of
monitoring, i.e., up to a 9 year
[[Page 59348]]
frequency. Section VIII.E, Table VIII.E.1 of this Preamble also
describes monitoring requirements to facilitate interpretation of the
requirements.
General: The Panel recommended that EPA explore options for
providing technical assistance to small entities to clearly communicate
the risks from radon in drinking water and indoor air, the rationale
supporting the regulation, and actions consumers can take to reduce
their risks. Therefore, this Preamble has been written to clarify to
the public the risks from radon in drinking water and radon in indoor
air, and the rationale supporting the proposed regulation (see Sections
I through V of this Preamble).
Areas in which Panel did not reach consensus: There were also a
number of issues discussed by the Panel on which consensus was not
reached. These included the appropriateness of the Agency's
affordability criteria for determining if affordable small system
compliance technologies are available, the appropriate level at which
to set the MCL, whether EPA should provide a ``model'' MMM program for
use by small systems in states that do not adopt state-wide MMM
programs, and whether information on the risks of radon and options for
reducing it provides ``health risk reduction benefits'' (as referenced
in the SDWA) independent of whether homes are actually mitigated or
built radon resistant. A detailed discussion of these issues is
included in the Panel report. EPA is requesting comment on some of
these issues in other parts of the preamble. To read the full
discussion of the issues on which EPA is requesting comment, see
Sections VII.A ``Requirements for Small Systems Serving 10,000 People
or Less'', VII.D ``Background on Selection of MCL and AMCL'', and VI.F
``Local CWS MMM Programs in Non-MMM States and State Role in Approval
of CWS MMM Program Plans.''
C. Unfunded Mandates Reform Act (UMRA)
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L.
104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under UMRA Section 202, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule, for which a written
statement is needed, Section 205 of the UMRA generally requires EPA to
identify and consider a reasonable number of regulatory alternatives
and adopt the least costly, most cost-effective or least burdensome
alternative that achieves the objectives of the rule. The provisions of
Section 205 do not apply when they are inconsistent with applicable
law. Moreover, Section 205 allows EPA to adopt an alternative other
than the least costly, most cost-effective or least burdensome
alternative if the Administrator publishes with the final rule an
explanation on why that alternative was not adopted.
Before EPA establishes any regulatory requirements that may
significantly or uniquely affect small governments, including tribal
governments, it must have developed, under Section 203 of the UMRA, a
small government agency plan. The plan must provide for notification to
potentially affected small governments, enabling officials of affected
small governments to have meaningful and timely input in the
development of EPA regulatory proposals with significant Federal
intergovernmental mandates and informing, educating, and advising small
governments on compliance with the regulatory requirements.
1. Summary of UMRA Requirements
EPA has determined that this rule contains a Federal mandate that
may result in expenditures of $100 million or more for State, local,
and tribal governments, in the aggregate, or the private sector in any
one year. Accordingly, EPA has prepared, under Section 202 of the UMRA,
a written statement addressing the following areas: (1) Authorizing
legislation; (2) cost-benefit analysis including an analysis of the
extent to which the costs to State, local, and tribal governments will
be paid for by the Federal government; (3) estimates of future
compliance costs; (4) macro-economic effects; and (5) a summary of
EPA's consultation with State, local, and tribal governments, a summary
of their concerns, and a summary of EPA's evaluation of their concerns.
A summary of this analysis follows and a more detailed description is
presented in EPA's Regulatory Impact Analysis (RIA) of the Radon Rule
(USEPA 1999f) which is included in the docket for this proposed
rulemaking.
(a) Authorizing legislation. Today's proposed rule is proposed
pursuant to Section 1412(b)(13) of the 1996 amendments to the SDWA
which requires EPA to propose and promulgate a national primary
drinking water regulation for radon, establishes a statutory deadline
of August 1999 to propose this rule, and establishes a statutory
deadline of August 2000 to promulgate this rule.
(b) Cost-benefit analysis. Section XIII.B of this preamble,
describing the Regulatory Impact Analysis (RIA) and Revised Health Risk
Reduction and Cost Analysis (HRRCA) for radon, contains a detailed
cost-benefit analysis in support of the radon rule. Today's proposed
rule is expected to have a total annualized cost of approximately $121
million with a range of potential impacts from $60.4 to $407.6 million,
depending on how many States and local PWSs adopt MMM programs and
comply with the AMCL. This total annualized cost consists of total
annual impacts on State, local, and tribal governments, in aggregate,
of approximately $53.5 million and total annual impacts on private
entities of approximately $67.6 million (Note: these estimates are
based on Scenario A which assumes 50 percent of States implement MMM
programs with the remaining 50 percent of States implementing system-
level MMM programs or complying with the MCL. Under Scenario E, total
costs are approximately $60.4 million. Total national costs of full
compliance with an MCL are approximately $407.6 million. Detailed
descriptions of the national costs and MMM scenarios are shown in
Section XIII of this preamble and Sections 9 and 10 of the RIA (USEPA
1999f).
The RIA includes both qualitative and monetized benefits for
improvements in health and safety. EPA estimates the proposed radon
rule will have annual monetized benefits of approximately $17.0 million
if the MCL were to be set at 4,000 pCi/L and $362 million if set at 300
pCi/L. The monetized health benefits of reducing radon exposures in
drinking water are attributable to the reduced incidence of fatal and
non-fatal cancers, primarily of the lung and stomach. Under baseline
assumptions (no control of radon exposure), 168 fatal cancers and 9.7
non-fatal cancers per year are associated with radon exposures through
CWSs. At a radon level of 4,000 pCi/L, an estimated 2.9 fatal cancers
and 0.2 non-fatal cancers per year are prevented. At a level 300 pCi/L,
62.0 fatal and 3.6 non-fatal cancers per year are prevented. The Agency
believes that compliance with an AMCL of 4,000 pCi/L and implementation
of a MMM program would result in health benefits equal to or greater
than those achieved by complying with the proposed MCL (300 pCi/L).
[[Page 59349]]
In addition to quantifiable benefits, EPA has identified several
potential non-quantifiable benefits associated with reducing radon
exposures in drinking water. These potential benefits are difficult to
quantify because of the uncertainty surrounding their estimation. Non-
quantifiable benefits may include any peace-of-mind benefits specific
to reduction of radon risks that may not be adequately captured in the
Value of Statistical Life (VSL) estimate. In addition, if chlorination
is added to the process of treating radon via aeration, arsenic pre-
oxidization will be facilitated. Neither chlorination nor aeration will
remove arsenic, but chlorination will facilitate conversion of Arsenic
(III) to Arsenic (V). Arsenic (V) is a less soluble form that can be
better removed by arsenic removal technologies. In terms of reducing
radon exposures in indoor air, provision of information to households
on the risks of radon in indoor air and the availability of options to
reduce exposure may be a non-quantifiable benefit that can be
attributed to some components of a MMM program. Providing such
information might allow households to make more informed choices about
the need for risk reduction given their specific circumstances and
concerns than they would have in the absence of a MMM program.
(i) State and Local Administrative Costs. States will incur a range
of administrative costs with the MCL and MMM/AMCL options in complying
with the radon rule. Administrative costs associated with water
mitigation can include costs associated with program management,
inspections, and enforcement activities. EPA estimates the total annual
costs of administrative activities for compliance with the MCL to be
approximately $2.5 million.
Additional administrative costs will be incurred by those States
who comply with the AMCL and develop an MMM program plan. In this case,
States will need to satisfy the four criteria for an acceptable MMM
program which include: (1) Involve the public in developing the MMM
program plan; (2) set quantitative State-wide goals for reducing radon
levels in indoor air; (3) submit and implement plans on existing and
new homes; and (4) develop and implement plans for tracking and
reporting results. The administrative costs will consist of the various
activities necessary to satisfy these four criteria. Because EPA is
unable to specify the number of States that will implement an MMM
program, administrative costs were estimated under two assumptions: (1)
50 percent of States (all water systems in those States) implement an
MMM program; and (2) 100 percent of States implement an MMM program,
since we expect that most States will choose this option.
If a State does not develop an MMM program plan, any local water
system may chose to meet the AMCL and prepare an MMM program plan for
State approval. Administrative costs to the State would consist
primarily of reviewing local program plans and overseeing compliance.
However, local water systems would bear administrative costs that
resemble the State costs to administer an MMM program. To estimate
costs for local water systems in these States, EPA assumed that all
local systems that exceeded 300 pCi/L but were less than 4,000 pCi/L
would choose to administer an MMM program rather than achieve the 300
pCi/L level through water mitigation. It is assumed that, on average,
water mitigation costs will exceed MMM program administrative costs for
local water systems.
EPA estimates that total annual costs of approximately $13.2
million are expected if half the States elect to administer an MMM
program and all local water systems in the remaining States undertake
MMM programs. In this case, costs to 50 percent of the States to
administer the MMM program ($2.9 million), and costs to 50 percent of
the States to approve MMM programs developed by local water systems
($7.8 million) are added to water mitigation costs ($2.5 million). In
this latter case there would also be costs to local water systems of
$45 million to develop and implement local MMM programs. This is the
total cost per year across all system sizes to develop and implement
system-level MMM programs and assumes approximately 45 percent of CWSs
will do a system-level MMM plan. The total costs across all system
sizes under Scenario E for system-level MMM programs is approximately
$5 million.
Various Federal financial assistance programs exist to help State,
local, and tribal governments comply with this rule. To fund
development and implementation of a MMM program, States have the option
of using Public Water Systems Supervision (PWSS) Program Assistance
Grant funds [SDWA Section 1443(a)(1)] and Program Management Set-Aside
funds from the Drinking Water State Revolving Fund (DWSRF) program.
Infrastructure funding to provide the equipment needed to ensure
compliance is available from the DWSRF program and may be available
from other Federal agencies, including the Housing and Urban
Development's Community Development Block Grant Program or the
Department of Agriculture's Rural Utilities Service.
EPA provides funding to States that have a primary enforcement
responsibility for their drinking water programs through the PWSS
grants program. States may use PWSS grant funds to establish and
administer new requirements under their primacy programs, including MMM
programs. PWSS grant funds may be used by a State to set-up and
administer a State MMM program.
States may also ``contract'' to other State agencies to assist in
the development or implementation of their primacy program, including
an MMM program for radon. However, States may not use grant funds to
contract to regulated entities (i.e., water systems) for MMM program
implementation.
An additional source of EPA funding to develop and implement a MMM
program is through the DWSRF program. The program awards capitalization
grants to States, which in turn use funds to provide low cost loans and
other types of assistance to eligible public water systems to assist in
financing the costs of infrastructure needed to achieve or maintain
compliance with SDWA requirements. The DWSRF program also allows a
State to set aside a portion of its capitalization grant to support
other activities that result in protection of public health and
compliance with the SDWA. The State Program Management set-aside (SDWA
Section 1452(g)(2)) allows a State to reserve up to ten percent of its
DWSRF allotment to assist in implementation of the drinking water
program. States must match expenditures under this set-aside dollar for
dollar. DWSRF State Program Management set-aside funds can be used to
fund activities to develop and run an MMM program, similar to those
eligible for funding from PWSS grant funds.
States may also use State Indoor Radon Grant (SIRG) funds to assist
States in funding their MMM programs. The Agency has determined that
activities that implement MMM activities and that meet current SIRG
eligibility requirements can be carried out with SIRG funds because the
goals of the MMM program reinforce and enhance the goals, strategies,
and priorities of the existing State indoor radon programs that rely on
funding through the SIRG program. However, expenditure of SIRG will not
be permitted to fund strictly water-related activities, such as testing
or monitoring of water by CWSs.
[[Page 59350]]
(c) Estimates of future compliance costs. To meet the requirement
in Section 202 of the UMRA, EPA analyzed future compliance costs and
possible disproportionate budgetary effects of both the MCL and MMM/
AMCL options. The Agency believes that the cost estimates, indicated
previously and discussed in more detail in Section XIII.B of today's
preamble accurately characterize future compliance costs of the
proposed rule.
(d) Macroeconomic effects. As required under UMRA Section 202, EPA
is required to estimate the potential macro-economic effects of the
regulation. These types of effects include those on productivity,
economic growth, full employment, creation of productive jobs, and
international competitiveness. Macro-economic effects tend to be
measurable in nationwide econometric models only if the economic impact
of the regulation reaches 0.25 percent to 0.5 percent of Gross Domestic
Product (GDP). In 1998, real GDP was $7,552 billion so a rule would
have to cost at least $18 billion annually to have a measurable effect.
A regulation with a smaller aggregate effect is unlikely to have any
measurable impact unless it is highly focused on a particular
geographic region or economic sector. The macro-economic effects on the
national economy from the radon rule should be negligible based on the
fact that, assuming full compliance with an MCL, the total annual costs
are approximately $43.1 million at the 4,000 pCi/L level and about
$407.6 million at the 300 pCi/L level (at a 7 percent discount rate)
and the costs are not expected to be highly focused on a particular
geographic region or industry sector.
(e) Summary of EPA's consultation with State, local, and tribal
governments and their concerns. Consistent with the intergovernmental
consultation provisions of section 204 of the UMRA and Executive Order
12875 ``Enhancing Intergovernmental Partnership,'' EPA has already
initiated consultations with the governmental entities affected by this
rule. EPA initiated consultations with governmental entities and the
private sector affected by this rulemaking through various means. This
included four stakeholder meetings, and presentations at meetings of
the American Water Works Association, the Association of State Drinking
Water Administrators, the Association of State and Territorial Health
Officials, and the Conference of Radiation Control Program Directors.
Participants in EPA's stakeholder meetings also included
representatives from National Rural Water Association, National
Association of Water Companies, Association of Metropolitan Water
Agencies, State department of environmental protection representatives,
State health department representatives, State water utility
representatives, the Inter Tribal Council of Arizona, and
representatives of other tribes. EPA also made presentations at tribal
meetings in Nevada, Alaska, and California. To address the proposed
rule's impact on small entities, the Agency convened a Small Business
Advocacy Review Panel in accordance with the Regulatory Flexibility Act
(RFA) as amended by the Small Business Regulatory Enforcement Fairness
Act (SBREFA). EPA also held two series of three conference calls with
representatives of State drinking water and State radon programs. In
addition to these consultations, EPA made presentations on the proposed
Radon Rule to the Association of California Water Agencies, the
National Association of Towns and Townships, the National League of
Cities, and the National Association of Counties. Several State
drinking water representatives also participated in AWWA's Technical
Workgroup for Radon.
The Agency also notified governmental entities and the private
sector of opportunities to provide input on the Health Risk Reduction
and Cost Analysis (HRRCA) for radon in drinking water in the Federal
Register on February 26, 1999 (64 FR 9559). The HRRCA was published six
months in advance of this proposal and illustrated preliminary cost and
benefit estimates for various MCL options under consideration for the
proposed rule. The comment period on the HRRCA ended on April 12, 1999,
and EPA received approximately 26 written comments. Of the 26 comments
received concerning the HRRCA, 42 percent were from States and 4
percent were from local governments.
The public docket for this proposed rulemaking contains meeting
summaries for EPA's four stakeholder meetings on radon in drinking
water, all comments received by the Agency, and provides details about
the nature of State, local, and tribal governments' concerns. A summary
of State, local, and tribal government concerns on this proposed
rulemaking is provided in the following section.
In order to inform and involve tribal governments in the rulemaking
process, EPA staff attended the 16th Annual Consumer Conference of the
National Indian Health Board on October 6-8, 1998, in Anchorage,
Alaska. Over nine hundred persons representing Tribes from across the
country were in attendance. During the conference, EPA conducted two
workshops for meeting participants. The objectives of the workshops
were to present an overview of EPA's drinking water program, solicit
comments on key issues of potential interest in upcoming drinking water
regulations, and to solicit advice in identifying an effective
consultative process with tribes for the future.
EPA, in conjunction with the Inter Tribal Council of Arizona
(ITCA), also convened a tribal consultation meeting on February 24-25,
1999, in Las Vegas, Nevada to discuss ways to involve tribal
representatives, both tribal council members and tribal water utility
operators, in the stakeholder process. Approximately twenty-five
representatives from a diverse group of tribes attended the two-day
meeting. Meeting participants included representatives from the
following tribes: Cherokee Nation, Nezperce Tribe, Jicarilla Apache
Tribe, Blackfeet Tribe, Seminole Tribe of Florida, Hopi Tribe, Cheyenne
River Sioux Tribe, Menominee Indian Tribe, Tulalip Tribes, Mississippi
Band of Choctaw Indians, Narragansett Indian Tribe, and Yakama Nation.
The major meeting objectives were to: (1) Identify key issues of
concern to tribal representatives; (2) solicit input on issues
concerning current OGWDW regulatory efforts; (3) solicit input and
information that should be included in support of future drinking water
regulations; and (4) provide an effective format for tribal involvement
in EPA's regulatory development process. EPA staff also provided a
brief overview on the forthcoming radon rule at the meeting. The
presentation included the health concerns associated with radon, EPA's
current position on radon in drinking water, the distinction between an
MCL and AMCL, the multimedia mitigation (MMM) program, and specific
issues for tribes. The following questions were posed to the tribal
representatives to begin discussion on radon in drinking water: (1)
Will tribal governments be interested in substituting MMM for drinking
water control; (2) what types of MMM could tribes reasonably implement;
and (3) what resources are available to fund MMM? The summary for the
February 24-25, 1999, meeting was sent to all 565 Federally recognized
tribes in the United States.
EPA also conducted a series of workshops at the Annual Conference
of the National Tribal Environmental Council which was held on May 18-
20, 1999, in Eureka, California. Representatives from over 50 tribes
attended all, or part, of these sessions.
[[Page 59351]]
The objectives of the workshops were to provide an overview of
forthcoming EPA regulations affecting water systems; discuss changes to
operator certification requirements; discuss funding for tribal water
systems; and to discuss innovative approaches to regulatory cost
reduction. Tribal representatives were generally supportive of
regulations which would ensure a high level of water quality, but
raised concerns over funding for regulations. With regard to the
forthcoming proposed radon rule, many tribal representatives saw the
multimedia mitigation option as highly desirable, but felt that this
option may not be adapted unless funds were made available for home
mitigation. Meeting summaries for EPA's tribal consultations are
available in the public docket for this proposed rulemaking.
(f) Nature of state, local, and tribal government concerns and how
EPA addressed these concerns. State and local governments raised
several concerns, including the high costs of the rule to small
systems; the high degree of uncertainty associated with the benefits;
the high costs of including Non-Transient Non-Community Water Systems
(NTNCWSs); and the inclusion of risks to both smokers and non-smokers
in the proposed regulation. Tribal governments raised several concerns
with the MMM program, including where the funding to mitigate homes
would come from; the number of homes that would require testing; and
the frequency of home testing.
EPA understands the State, local, and tribal government concerns
with the issues described previously. The Agency believes that the
options for small systems, proposed for public comment in this
rulemaking, will address stakeholder concerns pertaining to small
systems and will help to reduce the financial burden to these systems.
Non-Transient Non-Community Water Systems (NTNCWSs) are not subject
to this proposed rulemaking. A detailed discussion of the exposure to
radon in NTNCWSs is shown in Section XII.D of this preamble. EPA has
conducted a preliminary analysis on exposure and risks to NTNCWSs and
is soliciting public comment on this preliminary analysis. An analysis
of the potential benefits and costs of radon in drinking water for
NTNCWSs is included in the docket for this proposed rulemaking. (USEPA
1999m)
EPA has included the risks to both ever-smokers and never-smokers
in this proposed rulemaking. The Agency is basing this regulation on
the risks to the general population and is not excluding any particular
segments of the population. For a more complete discussion on the risks
of radon in drinking water and air, see Section XII of this preamble.
EPA understands tribal governments' concerns with funding for the
MMM program. To assist State, local, and tribal governments with the
implementation of an MMM program, EPA is making available Public Water
Supply Supervision (PWSS) Program Assistance Grant Funds, Drinking
Water State Revolving Fund (DWSRF) funds, and State Indoor Air Grant
(SIRG) funds. A more complete discussion of the funding available to
State, local, and tribal governments for MMM program implementation is
shown in Section XIV.C.1(b) of this preamble.
(g) Regulatory Alternatives Considered. As required under Section
205 of the UMRA, EPA considered several regulatory alternatives in
developing an MCL for radon in drinking water. In preparation for this
consideration, the Regulatory Impact Analysis and Health Risk Reduction
and Cost Analysis (HRRCA) for Radon evaluated radon levels of 100, 300,
500, 700, 1,000, 2,000, and 4,000 pCi/L.
The Regulatory Impact Analysis and HRRCA also evaluated national
costs and benefits of MMM implementation, with States choosing to
reduce radon exposure in drinking water through an Alternative Maximum
Contaminant Level (AMCL) and radon risks in indoor air through MMM
programs. Based on the National Academy of Sciences recommendations,
the AMCL level that was evaluated is 4,000 pCi/L. For further
discussion on the regulatory alternatives considered in this proposed
rulemaking, see Section XIII.B of this preamble.
EPA believes that the regulatory approaches proposed in today's
notice are the most cost-effective options for radon that achieve the
objectives of the rule, including strong public health protection. For
a complete discussion of this issue, see EPA's Regulatory Impact
Analysis and Revised HRRCA for Radon (USEPA 1999f).
2. Impacts on Small Governments
In preparation for the proposed radon rule, EPA conducted analysis
on small government impacts. This rule may significantly impact small
governments. EPA included small government officials or their
designated representatives in the rule making process. EPA conducted
four stakeholder meetings on the development of the radon rule which
gave a variety of stakeholders, including small governments, the
opportunity for timely and meaningful participation in the regulatory
development process. Groups such as the National Association of Towns
and Townships, the National League of Cities, and the National
Association of Counties participated in the proposed rulemaking
process. Through such participation and exchange, EPA notified
potentially affected small governments of requirements under
consideration and provided officials of affected small governments with
an opportunity to have meaningful and timely input into the development
of the regulatory proposal.
EPA also held a conference call on May 11, 1998, to consult
directly with representatives of small entities that may be affected by
the proposed rule. This conference call provided a forum for Small
Entity Representative (SER) input on key issues related to the proposed
radon rule. These issues included: (1) Issues related to the rule
development, such as radon health risks, occurrence of radon in
drinking water, treatment technologies, analytical methods, and
monitoring; and (2) issues related to the development and
implementation of the MMM program guidelines.
As required by SBREFA, EPA also convened a Small Business Advocacy
Review (SBAR) Panel to help further identify and incorporate small
entity concerns into this proposed rulemaking. For a sixty-day period
starting in July 1998, the Panel reviewed technical background
information related to this rulemaking, reviewed comments provided by
the SERs, and met on several occasions with EPA and on one occasion
with the SERs to identify issues and explore alternative approaches for
accomplishing environmental goals while minimizing impacts to small
entities. The SBAR final report on the proposed radon rule, which
includes a description of the SBAR Panel process and the Panel's
findings and recommendations, is available in the public docket for
this proposed rulemaking. For a more detailed discussion of the Panel
report, see Section XIV.B of this preamble.
In addition, EPA will educate, inform, and advise small systems,
including those run by small governments, about the radon rule
requirements. One of the most important components of this process is
the Small Entity Compliance Guide, required by the Small Business
Regulatory Enforcement Fairness Act of 1996 after the rule is
promulgated. This plain-English guide will explain what actions a small
entity must take to comply with the rule. Also, the Agency is
developing fact sheets that concisely describe various aspects and
requirements of the radon rule.
[[Page 59352]]
D. Paperwork Reduction Act (PRA)
The information collection requirements in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An
Information Collection Request (ICR) document has been prepared by EPA
(ICR, No. 1923.01) and a copy may be obtained from Sandy Farmer by mail
at OP Regulatory Information Division, U.S. Environmental Protection
Agency (2137), 401 M St., SW, Washington, DC 20460; by email at
farmer.sandy@epa.gov; or by calling (202) 260-2740. A copy may also be
downloaded off the Internet at http://www.epa.gov/icr.
Two types of information will be collected under the proposed radon
rule. First, information on individual water systems and their radon
levels will enable the States and EPA to evaluate compliance with the
applicable MCL or AMCL. This information, most of which consists of
monitoring results, corresponds to information routinely collected from
water systems for other types of drinking water contaminants. Radon
monitoring and reporting will initially be required on a quarterly
basis for at least one year, but thereafter the frequency may be
reduced to annually or once every three years depending on the level of
radon present (see Section VIII.E). Other existing information and
reporting requirements, such as Consumer Confidence Reports and
(proposed) public notification requirements, will be marginally
expanded to encompass radon along with other contaminants. As is the
case for other contaminants, required information on system radon
levels must be provided by affected systems and is not considered to be
confidential.
The second type of information relates to the MMM program, which is
EPA's recommended approach for small systems under the proposed radon
rule. Information of this type includes MMM plans prepared by States as
well as MMM plans prepared by community ground water systems in States
that do not develop a MMM plan. The proposed rule allows States to
prepare MMM plans regardless of whether they are primacy States with
respect to drinking water programs. EPA will review the MMM plans
developed by States, and States will review system-level MMM plans.
These reviews will help ensure that MMM programs are likely to achieve
meaningful reductions in human health risks from radon exposure.
Acceptable MMM plans will include a plan for the collection of data to
track the progress of the MMM program relative to goals established in
the plans (e.g., data on the number or rate of mitigated homes and the
number or rate of new homes built radon resistant). EPA will review
State-level MMM programs at least every five years, and States will
review system-level programs at least every five years. Information
related to MMM programs (i.e., the MMM plans and tracking data) is
mandatory for States that choose to implement an EPA-approved MMM
program and enforce the AMCL for radon rather than the MCL. Similarly,
information related to system-level MMM programs is required only from
systems that comply with the AMCL rather than the MCL and are in States
that do not have a MMM program in place.
EPA believes the information discussed previously, on compliance
with the MCL or AMCL and on MMM programs, is essential to achieving the
radon-related health risk reductions anticipated by EPA under the
proposed rule.
EPA has estimated the burden associated with the specific record
keeping and reporting requirements of the proposed rule in an
accompanying Information Collection Request (ICR), which is available
in the public docket for this proposed rulemaking. Burden means the
total time, effort, or financial resources expended by persons to
generate, maintain, retain, or disclose or provide information to or
for a Federal agency. This includes the time needed to review
instructions; develop, acquire, install, and utilize technology and
systems for the purposes of collecting, validating, and verifying
information, processing and maintaining information, and disclosing and
providing information; adjust the existing ways to comply with any
previously applicable instructions and requirements; train personnel to
be able to respond to a collection of information; search data sources;
complete and review the collection of information; and transmit or
otherwise disclose the information.
EPA has estimated a range of administrative costs for the proposed
rule. These costs do not include testing and mitigating water or
testing and mitigating households in the MMM program. The PRA requires
that average annual cost and labor for administrative costs be
calculated over a three-year period. These costs are presented next.
However, because the full implementation of the proposed rule does not
occur until later years, average annual cost and labor for a 20-year
period are also presented. These 20-year average annual costs are
presented by scenarios defined by the proportions of systems that elect
to develop system-level MMM programs and the proportions of states that
elect to implement state-wide MMM programs. These scenarios are
described in detail in Section XIII.G and Section 9 of the RIA (USEPA
1999f). Based on these analyses, EPA's burden estimates for the
proposed rule, in both costs and hours, are as follows:
Administrative costs to community groundwater systems for
mitigation-related activities are estimated to be $14.6 million per
year ($357 per system) or 267,625 hours, distributed by system size as
shown in Table XIV.2. All 40,863 community groundwater systems will
bear these costs under all scenarios evaluated.
In the first three years of the rule, there are no
administrative costs to community groundwater systems for MMM program
activities.
Table XIV.2.--Administrative Costs to Community Water Systems Associated
With Water Mitigation and System-Level MMM Programs (Excluding MMM
Testing and Mitigation)
------------------------------------------------------------------------
Administrative
Administrative costs of
System size (customers served) costs of water system-level
mitigation ($ MMM programs
per year) ($ per year)
------------------------------------------------------------------------
VVS (25-100)............................ 4,485,485 0
VVS (101-500)........................... 4,958,735 0
VS (501-3,300).......................... 3,430,387 0
S (3,301-10,000)........................ 848,487 0
M (10,001-100K)......................... 491,944 0
[[Page 59353]]
L (>100K)............................... 23,579 0
-------------------------------
Total For All Systems........... 14,598,617 0
------------------------------------------------------------------------
Administrative costs to States for water mitigation-
related activities are to be approximately $3 million per year (Table
XIV.3) and 119,625 hours, or approximately $65,400 per year per state
and 2,600 hours per year per state. Forty-six states bear these costs
under all scenarios.
Table XIV.3 presents the costs if 100 percent of all states were to
incur the specific administrative costs listed. However, no state will
bear 100 percent of state-wide MMM program costs and 100 percent of
system-level MMM program costs. These costs will be borne in an inverse
relationship; e.g., 95 percent of the states will bear administrative
costs associated with state-wide MMM programs and 5 percent of states
will bear administrative costs associated with system-level MMM
programs.
Table XIV.3.--State Administrative Costs for Water Mitigation and MMM
Programs
------------------------------------------------------------------------
($ per
year)
------------------------------------------------------------------------
Water Mitigation........................................... 3,009,713
State-Wide MMM Programs.................................... 6,346
System-Level MMM Programs.................................. 5,909
Total State Administrative Costs....................... 3,021,968
------------------------------------------------------------------------
State administrative costs associated with state-wide MMM
programs are estimated up to $6,300 per year and up to 140 hours per
year for the first three years of the rule.
State administrative costs to review system-level MMM
programs and related activities are estimated up to $5,900 per year and
up to 123 hours per year for the first three years of the rule.
The total State administrative costs (water mitigation,
state-wide, and system-level MMM programs) are estimated up to
approximately $3 million per year and 119,887 hours per year.
Because much of the activity required under the proposed rule
occurs in later years, this analysis presents average administrative
costs borne by systems and states over a 20 year period. Again, these
costs do not include water testing and mitigation or testing and
mitigating households in MMM programs. In addition, these costs are
presented by scenarios that are defined by the proportions of systems
that elect to develop system-level MMM programs and the proportions of
states that elect to implement state-wide MMM programs.
Administrative costs to community groundwater systems for
mitigation-related activities are estimated to be $8.6 million per year
($211 per system) or 145,547 hours per year, distributed by system size
as shown in Table XIV.4. All 40,863 community groundwater systems will
bear these costs under all scenarios evaluated.
Under Scenario A, administrative costs to community
groundwater systems for MMM program activities are approximately $45.1
million per year ($2,452 per system) or 174,000 hours per year for the
18,388 systems (45 percent of all community groundwater systems) that
develop and file an MMM plan. The costs are distributed across the
system size categories as shown in Table XIV.4. Under Scenario E,
administrative costs to systems are $5.0 million per year or 19,333
hours per year. The per-system cost is the same as Scenario A, but only
five percent of systems (2,042) bear these costs.
Table XIV.4.--Administrative Costs to Community Water Systems Associated With Water Mitigation and System-Level
MMM Programs
[Excluding MMM Testing and Mitigation]
----------------------------------------------------------------------------------------------------------------
Administrative Administrative
Administrative costs of costs of
costs of water system-level system-level
System size (customers served) mitigation ($ MMM programs MMM programs
per year) under scenario under scenario
A ($ per year E ($ per year
----------------------------------------------------------------------------------------------------------------
VVS (25-100).................................................... 2,857,190 14,978,142 1,664,238
VVS (101-500)................................................... 2,923,970 15,328,217 1,703,135
VS (501-3,300).................................................. 2,022,764 10,603,857 1,178,206
S (3,301-10,000)................................................ 500,319 2,622,804 291,423
M (10,001-100K)................................................. 290,080 1,520,674 168,964
L (>100K)....................................................... 13,904 72,886 8,097
-----------------------------------------------
Total for All Systems................................... 8,608,226 45,126,581 5,014,065
----------------------------------------------------------------------------------------------------------------
[[Page 59354]]
Total administrative costs to community water systems
(water mitigation plus MMM programs) range from $11 million per year
under Scenario E to $51.2 million under Scenario A or 165,000 hours
under Scenario E to 320,000 hours under Scenario A. The costs are
distributed across the various system sizes as shown in Table XIV.5.
Table XIV.5.--Total Administrative Costs Water Mitigation and MMM
Programs to Community Groundwater Systems
------------------------------------------------------------------------
Total Total
administrative administrative
System size (customers served) costs under costs under
scenario A ($ scenario E ($
per year) per year)
------------------------------------------------------------------------
VVS (25-100)............................ 16,990,791 3,676,887
VVS (101-500)........................... 17,387,906 3,762,824
VS (501-3,300).......................... 11,238,829 1,813,178
S (3,001-10,000)........................ 3,412,697 1,081,316
M (10,001-100,000)...................... 1,873,106 521,396
L (100,000)............................. 256,893 192,105
-------------------------------
Total for All Systems........... 51,160,223 11,047,707
------------------------------------------------------------------------
Administrative costs to States for water mitigation-
related activities are estimated to be approximately $2.5 million per
year (Table XIV.6) or approximately $53,900 per year per state. Total
state burden is approximately 100,000 hours per year. Forty-six states
bear these costs under all scenarios.
Table XIV.6.--State Administrative Costs for Water Mitigation and MMM
Programs
[$ per year]
------------------------------------------------------------------------
Scenario A Scenario E
------------------------------------------------------------------------
Water Mitigation........................ 2,477,299 2,477,299
State-Wide MMM Programs................. 2,926,691 5,560,713
System-Level MMM Programs............... 7,830,995 870,111
-------------------------------
Total State Administrative Costs 13,234,985 8,908,123
------------------------------------------------------------------------
State administrative costs associated with state-wide MMM
programs are estimated to be $2.9 million dollars ($127,200 per state
across 23 states) or 123,000 hours per year under Scenario A. Under
Scenario E, estimated state administrative costs of state-level MMM
programs are estimated to be $5.6 million (again $126,400 per state,
but under this scenario, 44 states bear the costs) or 233,000 hours per
year for all 44 states.
State administrative costs to review system-level MMM
programs and related activities are estimated to be $7.8 million per
year or 316,410 hours per year under Scenario A and approximately
$870,000 per year or 35,157 hours per year under Scenario E. In both
cases the cost per state is approximately $371,000 per year, with 21
states affected under Scenario A and two states affected under Scenario
E.
The total State administrative costs (water mitigation,
state-wide, and system-level MMM programs) are estimated to be $13.2
million per year or 538,845 hours per year under Scenario A and $8.9
million per year or 367,878 hours per year under Scenario E.
An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
Comments are requested on the Agency's need for this information,
the accuracy of the provided burden estimates, and any suggested
methods for minimizing respondent burden, including through the use of
automated collection techniques. Send comments on the ICR to the
Director, OP Regulatory Information Division, U.S. Environmental
Protection Agency (2137), 401 M St., SW., Washington, DC 20460 and to
the Office of Management and Budget, 725 17th St., NW., Washington, DC
20503, marked ``Attention: Desk Officer for EPA''. Include the ICR
number (1923.01) in any correspondence. Since OMB is required to make a
decision concerning the ICR between 30 and 60 days after November 2,
1999, a comment to OMB is best assured of having its full effect if OMB
receives it by December 2, 1999. The final rule will respond to any OMB
or public comments on the information collection requirements contained
in this proposal.
E. National Technology Transfer and Advancement Act (NTTAA)
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law 104-113, Sec. 12(d) (15 U.S.C. 272
note) directs EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standard bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards.
EPA's process for selecting the analytical test methods is
consistent with Section 12(d) of the NTTAA. EPA performed literature
searches to identify analytical methods from industry, academia,
voluntary consensus standard bodies, and other parties that could be
[[Page 59355]]
used to measure radon in drinking water.
This proposed rulemaking involves technical standards. EPA proposes
to use Standard Method 7500-Rn, which is specific for radon 222 (radon)
in drinking water, for both the MCL and AMCL for radon in drinking
water. This method meets the objectives of the rule because it
accurately and reliably detects radon in drinking water below 100 pCi/
L. Standard Method 7500-Rn was approved by the Standard Methods
Committee in 1996 and is described in the ``Standard Methods for the
Examination of Water and Wastewater (19th Edition Supplement)'' which
was prepared and published jointly by the American Public Health
Association, American Water Works Association, and Water Environment
Federation. Additional information on this method is shown in Section
VIII.B.2 of today's preamble.
EPA is also proposing the use of the American Society for Testing
and Materials (ASTM) Standard Test Method for Radon in Drinking Water
(designation: D5072-92) for the AMCL for radon in drinking water. This
method is specific for radon in drinking water, but has been shown to
accurately and reliably detect radon only at concentrations above 1,500
pCi/L and thus is only useful for the AMCL. ASTM's Standard Test Method
for Radon in Drinking Water was adopted by ASTM in 1992 and is
described in the Annual Book of ASTM Standards. Additional information
on this method is shown in Section VIII.B.2 of this preamble.
As discussed in Section VIII.B (Analytical Methods) of this
preamble, EPA is in the process of adopting the Performance-Based
Measurement System (PBMS) to allow greater flexibility in compliance
monitoring for this proposed rule and for future rules. For further
information on PBMS, see Section VIII.D.
EPA welcomes comments on this aspect of the proposed rulemaking
and, specifically, invites the public to identify potentially-
applicable voluntary consensus standards and to explain why such
standards should be used in this regulation.
F. Executive Order 12898: Environmental Justice
Executive Order 12898 ``Federal Actions To Address
EnviroPopulations and Low-Income Populations,'' 59 FR 7629 (February
16, 1994) establishes a Federal policy for incorporating environmental
justice into Federal agency missions by directing agencies to identify
and address disproportionately high and adverse human health or
environmental effects of its programs, policies, and activities on
minority and low-income populations. The Agency has considered
environmental justice related issues concerning the potential impacts
of this action and has consulted with minority and low-income
stakeholders by convening a stakeholder meeting via video conference
specifically to address environmental justice issues.
As part of EPA's responsibilities to comply with E.O. 12898, the
Agency held a stakeholder meeting via video conference on March 12,
1998, to address various components of pending drinking water
regulations; and how they may impact sensitive sub-populations,
minority populations, and low-income populations. Topics discussed
included treatment techniques, costs and benefits, data quality, health
effects, and the regulatory process. Participants included national,
State, tribal, municipal, and individual stakeholders. EPA conducted
the meeting by video conference call between eleven cities. This
meeting was a continuation of stakeholder meetings that started in 1995
to obtain input on the Agency's Drinking Water programs. The major
objectives for the March 12, 1998, meeting were: (1) Solicit ideas from
Environmental Justice (EJ) stakeholders on known issues concerning
current drinking water regulatory efforts; (2) identify key issues of
concern to EJ stakeholders; and (3) receive suggestions from EJ
stakeholders concerning ways to increase representation of EJ
communities in OGWDW regulatory efforts. In addition, EPA developed a
plain-English guide specifically for this meeting to assist
stakeholders in understanding the multiple and sometimes complex issues
surrounding drinking water regulation. A meeting summary for the March
12, 1998, stakeholder meeting is available in the public docket for
this proposed rulemaking.
Stakeholders have raised concerns that this action may have a
disproportionate impact on low-income and minority populations. The
rule framework and in particular, the MMM program coupled with a 4,000
pCi/L AMCL, were discussed with EJ stakeholders at the March 12, 1998,
meeting. Key issues of concern with the MMM/AMCL approach included: (1)
The potential for an uneven distribution of benefits across water
systems and society; (2) the cost of air remediation to apartment
dwellers; and (3) the concern that the approach could provide water
systems and State governments a ``loophole'' through which they could
escape the responsibility of providing appropriate protection from
radon exposures.
The Agency considered equity-related issues concerning the
potential impacts of MMM program implementation. There is no factual
basis to indicate that minority and low income or other communities are
more or less exposed to radon in drinking water than the general
public. However, some stakeholders expressed more general concerns
about equity in radon risk reduction that could arise from the MMM/AMCL
framework outlined in SDWA. One concern is the potential for an uneven
distribution of risk reduction benefits across water systems and
society. Under the proposed framework for the rule, customers of CWSs
complying with the AMCL could be exposed to a higher level of radon in
drinking water than if the MCL were implemented, though this level
would not be higher than the background concentration of radon in
ambient air. However, these CWS customers could also save the cost,
through lower water rates, of installing treatment technology to comply
with the MCL. Under the proposed regulation, CWSs and their customers
have the option of complying with either the AMCL (associated with a
State or local MMM program) or the MCL.
EPA believes it is important that these issues and choices be
considered in an open public process as part of the development of MMM
program plans. Therefore, EPA has incorporated requirements into the
proposed rule that provide a framework for consideration of equity
concerns with the MMM/AMCL. The proposed rule includes requirements for
public participation in the development of MMM program plans, as well
as for notice and opportunity for public comment. EPA believes that the
requirement for public participation will result in State and CWS
program plans that reflect and meet their different constituents needs
and concerns and that equity issues can be most effectively dealt with
at the State and local levels with the participation of the public. In
developing their MMM program plans, States and CWSs are required to
document and consider all significant issues and concerns raised by the
public. EPA expects and strongly recommends that States and CWSs pay
particular attention to addressing any equity concerns that may be
raised during the public participation process. In addition, EPA
believes that providing CWS customers with information about the health
risks of radon and on the
[[Page 59356]]
AMCL and MMM program option will help to promote understanding of the
health risks of radon in indoor air, as well as in drinking water, and
help the public to make informed choices. To this end, EPA is requiring
CWSs to alert consumers to the MMM approach in their State in consumer
confidence reports issued between publication of the final radon rule
and the compliance dates for implementation of MMM programs. This will
include information about radon in indoor air and drinking water and
where consumers can get additional information.
The proposed requirements include the following: (1) A description
of processes the State used to provide for public participation in the
development of its MMM program plan; (2) a description of the nature
and extent of public participation that occurred, including a list of
groups and organizations that participated; (3) a summary describing
the recommendations, issues, and concerns arising from the public
participation process and how these were considered in developing the
State's MMM program plan; (4) a description of how the State made
information available to the public to support informed public
participation, including information on the State's existing indoor
radon program activities and radon risk reductions achieved, and on
options considered for the MMM program plan along with any analyses
supporting the development of such options; and (5) the State must
provide notice and opportunity for public comment on the plan prior to
submitting it to EPA.
The public is invited to comment on this aspect of the proposed
rulemaking and, specifically, to recommend additional methods to
address EJ concerns with the MMM/AMCL approach for treating radon in
drinking water.
G. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
Executive Order 13045, ``Protection of Children from Environmental
Health Risks and Safety Risks,'' 62 FR 19885 (April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under E.O. 12866, and (2) concerns an environmental health
or safety risk that EPA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the Agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency.
This proposed rule is not subject to the Executive Order because
the Agency does not have reason to believe the environmental health
risks or safety risks addressed by this action present a
disproportionate risk to children. Based on the risk assessment for
radon in drinking water developed by the NAS, children were not
identified as being disproportionately impacted by radon. The Committee
on Risk Assessment of Exposure to Radon in Drinking Water that
conducted the National Research Council Risk Assessment of Radon in
Drinking Water Study (NAS 1999b) concluded, except for the lung cancer
risk to smokers, there is insufficient scientific information to permit
quantitative evaluation of radon risks to susceptible subpopulations
such as infants, children, pregnant women, elderly, and seriously ill
persons.
The National Academy of Sciences Committee on the Biological
Effects of Ionizing Radiation (BEIR VI) (NAS 1999a) noted that there is
only one study (tin miners in China) that provides data on whether
risks from radon progeny are different for children, adolescents, and
adults. Based on this study, the committee concluded that there was no
clear indication of an effect of age at exposure, and the committee
made no adjustments in the model for exposures received at early ages
(NAS 1999a). Nonetheless, we evaluated the environmental health or
safety effects of radon in drinking water on children. The results of
this evaluation are contained in Section XII of this preamble. Copies
of the documents used to evaluate the environmental health or safety
effects of radon in drinking water on children, including the NAS
Reports, have been placed in the public docket for this proposed
rulemaking.
The public is invited to submit or identify peer-reviewed studies
and data, of which EPA may not be aware, that assessed results of early
life exposure to radon in drinking water.
H. Executive Orders on Federalism
Under Executive Order 12875, ``Enhancing the Intergovernmental
Partnership,'' 58 FR 58093 (October 28, 1993) EPA may not issue a
regulation that is not required by statute and that creates a mandate
upon State, local, or tribal government, unless the Federal government
provides the funds necessary to pay the direct compliance costs
incurred by those governments, or EPA consults with those governments.
If EPA complies by consulting, E.O. 12875 requires EPA to provide to
the Office of Management and Budget a description of the extent of
EPA's prior consultation with representatives of affected State, local,
and tribal governments, the nature of their concerns, any written
communications from the governments, and a statement supporting the
need to issue the regulation. In addition, E.O. 12875 requires EPA to
develop an effective process permitting elected officials and other
representatives of State, local, and tribal governments ``to provide
meaningful and timely input in the development of regulatory proposals
containing significant unfunded mandates.''
EPA has concluded that this rule will create a mandate on State,
local, and tribal governments and the Federal government will not
provide the funds necessary to pay the direct costs incurred by State,
local, and tribal governments in complying with the mandate. In
developing this rule, EPA consulted with State, local, and tribal
governments to enable them to provide meaningful and timely input in
the development of this rule.
As described in Section XIV.C.1.e, EPA held extensive meetings with
a variety of State and local representatives, who provided meaningful
and timely input in the development of the proposed rule. Summaries of
the meetings have been included in the public docket for this proposed
rulemaking. See Sections XIV.C.1.e and XIV.C.1.f for summaries of the
extent of EPA's consultation with State, local, and tribal governments;
the nature of the governments' concerns; and EPA's position supporting
the need to issue this rule.
On August 4, 1999, President Clinton issued a new executive order
on federalism, Executive Order 13132 [64 FR 43255 (August 10, 1999)],
which will take effect on November 2, 1999. In the interim, the current
Executive Order 12612 [52 FR 41685 (October 30, 1987)], on federalism
still applies. This rule will not have a substantial direct effect on
States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among
various levels of government, as specified in Executive Order 12612.
``This proposed rule establishes a National Primary Drinking Water
Regulation (NPDWR) for the control of radon. This regulation is
required by section 1412(b)(13) of the Safe Drinking Water Act, as
amended. EPA conducted extensive discussions with States and local
governments in developing this proposal, and significant flexibility is
provided in implementing these regulations.''
[[Page 59357]]
I. Executive Order 13084: Consultation and Coordination With Indian
Tribal Governments
Under Executive Order 13084, ``Consultation and Coordination with
Indian Tribal Governments,'' 63 FR 27655 (May 19, 1998) EPA may not
issue a regulation that is not required by statute, that significantly
or uniquely affects the communities of Indian tribal governments, and
that imposes substantial direct compliance costs on those communities,
unless the Federal government provides the funds necessary to pay the
direct compliance costs incurred by the tribal governments, or EPA
consults with those governments. If EPA complies by consulting, E.O.
13084 requires EPA to provide the Office of Management and Budget, in a
separately identified section of the preamble to the rule, a
description of the extent of EPA's prior consultation with
representatives of affected tribal governments, a summary of the nature
of their concerns, and a statement supporting the need to issue the
regulation. In addition, E.O. 13084 requires EPA to develop an
effective process permitting elected officials and other
representatives of Indian tribal governments ``to provide meaningful
and timely input in the development of regulatory policies on matters
that significantly or uniquely affect their communities.''
EPA has concluded that this rule will significantly or uniquely
affect communities of Indian tribal governments. It will impose
substantial direct compliance costs on such communities, and the
Federal government will not provide the funds necessary to pay the
direct costs incurred by the tribal governments in complying with the
rule. In developing this rule, EPA consulted with representatives of
tribal governments pursuant to both E.O. 12875 and E.O. 13084.
Summaries of the meetings have been included in the public docket for
this proposed rulemaking. EPA's consultation, the nature of the
governments' concerns, and EPA's position supporting the need for this
rule are discussed in Section XIV.C.2 of this preamble.
J. Request for Comments on Use of Plain Language
Executive Order 12866 and the President's memorandum of June 1,
1998, require each agency to write all rules in plain language. We
invite your comments on how to make this proposed rule easier to
understand. For example:
Have we organized the material to suit your needs?
Are the requirements in the rule clearly stated?
Does the rule contain technical language or jargon that
isn't clear?
Would a different format (grouping and order of sections,
use of headings, paragraphing) make the rule easier to understand?
Would more (but shorter) sections be better?
Could we improve clarity by adding tables, lists, or
diagrams?
What else could we do to make the rule easier to
understand?
Stakeholder Involvement
XV. How Has the EPA Provided Information to Stakeholders in
Development of This NPRM?
A. Office of Ground Water and Drinking Water Website
EPA's Office of Ground Water and Drinking Water maintains a website
on radon at the following address: http://www.epa.gov/safewater/
radon.html. Documents are placed on the website for public access.
B. Public Meetings
EPA has consulted with a broad range of stakeholders and technical
experts. Participants in a series of stakeholder meetings held in 1997
and 1998 included representatives of public water systems, State
drinking water and indoor air programs, tribal water utilities and
governments, environmental and public health groups, and other Federal
agencies. EPA convened an expert panel in Denver in November, 1997, to
review treatment technology costing approaches. The panel made a number
of recommendations for modification to EPA cost estimating protocols
that have been incorporated into the radon cost estimates. EPA also
consulted with a subgroup of the National Drinking Water Advisory
Council (NDWAC) on evaluating the benefits of drinking water
regulations. The NDWAC was formed in accordance with the Federal
Advisory Committee Act (FACA) to assist and advise EPA. A variety of
stakeholders participated in the NDWAC benefits working group,
including utility company staff, environmentalists, health
professionals, State water program staff, a local elected official,
economists, and members of the general public.
EPA conducted one-day public meetings in Washington, D.C. on June
26, 1997; in San Francisco, California on September 2, 1997; and in
Boston, Massachusetts on October 30, 1997, to discuss its plans for
developing a proposed NPDWR for radon-222. EPA presented information on
issues related to developing the proposed NPDWR and solicited
stakeholder comments at each meeting. EPA also held a series of
conference calls in 1998 and 1999 with State drinking water and indoor
air programs, to discuss issues related to developing guidelines for
multiedia mitigation programs. EPA also held a public meeting in
Washington, DC. on March 16, 1999, to discuss the HRRCA published on
February 26, 1999, and the multimedia mitigation framework.
C. Small Entity Outreach
EPA has conducted outreach directly to representatives of small
entities that may be affected by the proposed rule, as part of SBREFA.
A full discussion of the small entity outreach is in Section XIV.B.6
``Significant Regulatory Alternatives and SBAR Panel Recommendations.''
D. Environmental Justice Initiatives
In order to uphold Executive Order 12898, ``Federal Actions to
Address Environmental Justice in Minority Populations and Low-Income
Populations,'' EPA's Office of Ground Water and Drinking Water convened
a public meeting in Washington, DC in March 1998 to discuss ways to
involve minority, low-income, and other sensitive subgroups in the
stakeholder process and to obtain input on the proposed radon rule. The
meeting was held in a video-conference format linking EPA Regions I
through IX to involve as many stakeholders as possible. EPA has taken
the concerns and issues raised by the environmental justice community
into account while setting the MCL, MCLG, and AMCL for radon. For more
information on the March 1998 environmental justice meeting, and on EPA
proposals to address concerns of stakeholders, see Section XIV.F of
this Preamble.
E. AWWA Radon Technical Work Group
The American Water Works Association (AWWA) convened a ``Radon
Technical Work Group,'' in 1998 that provided technical input on EPA's
update of technical analyses (occurrence, analytical methods, and
treatment technology), and discussed conceptual issues related to
developing guidelines for multimedia mitigation programs. Members of
the Radon Technical Work Group included representatives from State
drinking water and indoor air programs, public water systems, drinking
water testing laboratories, environmental groups and the U.S.
Geological Survey.
[[Page 59358]]
Background
XVI. How Does EPA Develop Regulations to Protect Drinking Water?
A. Setting Maximum Contaminant Level Goal and Maximum Contaminant Level
EPA sets an MCLG and MCL or treatment technology for each regulated
contaminant. The MCLG is based on analysis of health effects of the
contaminant. Based on the carcinogenicity of ionizing radiation, and
the NAS' current recommendation for a linear, non-threshold
relationship between exposure to radon and cancer in humans (NAS
1999a), the Agency is proposing an MCLG of zero for radon in drinking
water.
A drinking water MCL applies to finished (treated) drinking water
as supplied to customers. The SDWA generally requires that EPA set the
MCL for each contaminant as close as feasible to the corresponding
MCLG, based on available technology and taking costs into account. For
example, if the analytical methods will only allow a relatively
confident measure of a contaminant at a certain level, then the MCL
cannot practically be set below that level. In addition, the cost of
water treatment technologies is considered. If treatment capabilities
are limited then the MCL must be set at a level that is found to be
feasible. The MCL set by EPA must be protective of public health.
The 1996 amendments to SDWA require the Administrator to do a cost-
benefit analysis of the MCLs under consideration and to make a
determination as to whether the benefits of an MCL under consideration
justify the costs (1412(b)(3)(C)). The Administrator may set an MCL at
a level less stringent than the feasible level if he/she finds that the
benefits of the feasible MCL do not justify the costs (1412(b)(6)(A)).
There are certain exceptions to the use of this authority
(1412(b)(6)(B) and (C)).
B. Identifying Best Available Treatment Technology
As discussed also in Section VIII of this preamble, EPA identifies
one or more water treatment technologies (i.e., best available
treatment (BAT)) found to be effective in removing the contaminant from
drinking water and capable of meeting the MCL. There are a number of
physical, chemical, and other means used by such treatment technologies
for removing the contaminant, or in some cases destroying the
contaminant or otherwise changing the contaminant's composition. In
assessing potential BATs, EPA examines removal efficiency, cost to
purchase and maintain, compatibility with other processes, and other
factors. Most of the information cited by EPA in this context is
gleaned from technical literature, including research studies covering
pilot or full scale treatments. If some of the treatments identified
are found to be most efficient, practical and economical, EPA places
these on the BAT list and on occasion may provide guidance on other
treatments that may have certain limitations.
C. Identifying Affordable Treatment Technologies for Small Systems
The 1996 Amendments to the SDWA directed EPA to identify treatment
technologies that are affordable for small water systems. EPA is
charged with identifying affordable treatments for three small system
population categories: systems serving from 25 to 500, 501 to 3,300,
and 3,301 to 10,000 persons. A designated ``compliance technology'' for
these small systems may be a technology that is affordable and that
achieves compliance with the MCL or a treatment technique requirement.
Possible compliance technologies may include packaged or modular
systems, and point-of-entry (POE) or point-of-use (POU) type treatment
units. As with BAT designations, the compliance technology(ies)
selected by EPA must be based upon available information from technical
journals and/or qualified research studies.
EPA must also identify affordable ``variance technologies'' which
are to be installed by a public water system after the system has
applied to the responsible primacy agency for a variance, i.e., a
``small system variance.'' This variance applies only to systems
serving fewer than 10,000 people. It also applies only in cases where
an affordable technology is not available to achieve compliance with an
MCL (or treatment technique requirement) yet still will be protective
of public health. One of the requirements for systems that have
obtained a variance is to install and maintain the variance technology
in accordance with the listing by EPA, which may be specific to system
size and/or dependent upon source water quality. A small system
variance may only be obtained if compliance with the MCL through
alternate source, treatment, or restructuring options are deemed not to
be affordable for that system.
Small system variances are not available to meet MCL or treatment
technique requirements promulgated prior to 1986, nor for regulations
addressing microbiological contamination of water.
D. Requirements for Monitoring, Quality Control, and Record Keeping
Water systems are responsible for conducting monitoring of drinking
water to ensure that it meets all drinking water standards. To do this,
water systems and States use analytical methods set out in EPA
regulations.
EPA is responsible for evaluating analytical methods developed for
drinking water and approves those methods that it determines meet
Agency requirements. Laboratories analyzing drinking water compliance
samples must be certified by the EPA or the State.
Whether addressing regulated or unregulated contaminants, EPA
establishes requirements as to how often water systems must monitor for
the presence of the subject contaminant. Water systems serving larger
populations generally must conduct more monitoring (temporally and
spatially) because there is a greater potential human health impact of
any violation, and because of the physical extent of larger water
systems (e.g., miles of pipeline carrying water). Small water systems
can receive variances or exemptions from monitoring in limited
circumstances. In addition, under certain conditions, a State may have
the option to modify monitoring requirements on an interim or a
permanent basis for regulated contaminants, with a few exceptions.
States may use this flexibility to reduce monitoring requirements for
systems with low risk of incurring a violation.
E. Requirements for Water Systems to Notify Customers of Test Results
if Not in Compliance
Each owner or operator of a public water system must notify
customers if the system has failed to comply with an MCL or treatment
technique requirement, or a testing procedure required by EPA
regulation. A system must notify its customers if the system is subject
to a variance (due to an inability to comply with an MCL).
The form of this notification must be readily understood and
delivered via mail or direct delivery, through an annual report, or in
the first water billing cycle following such a drinking water
violation. The notification must also contain important information
about the contaminant so that consumers will be aware of any particular
hazards involved; the notification may indicate whether water can/
cannot be consumed or used for bathing, whether boiling drinking water
[[Page 59359]]
will make it safe; or whether storing water before use may be
advisable.
F. Approval of State Drinking Water Programs to Enforce Federal
Regulations
Section 1413 of the SDWA sets requirements that a State or eligible
Indian tribe must meet in order to maintain primary enforcement
responsibility (primacy) for its public water systems. These include
(1) adopting drinking water regulations that are no less stringent than
Federal NPDWRs; (2) adopting and implementing adequate procedures for
enforcement; (3) keeping records and making reports available on
activities that EPA requires by regulation; (4) issuing variances and
exemptions (if allowed by the State) under conditions no less stringent
than allowed by Sections 1415 and 1416; (5) adopting and being capable
of implementing an adequate plan for the provision of safe drinking
water under emergency situations, and (6) adopting authority for
administrative penalties.
In addition to adopting the basic primacy requirements, States may
be required to adopt special primacy provisions pertaining to a
specific regulation. These regulation-specific provisions may be
necessary where implementation of the NPDWR involves activities beyond
those in the generic rule. States are required by 40 CFR 142.12 to
include these regulation-specific provisions in an application for
approval of their program revisions.
XVII. Important Technical Terms
Adsorption: In the case of the water/solid interface, the
accumulation of a dissolved chemical species at the interface between a
solid material (e.g., granular activated carbon) and water.
Alpha particle: A radioactivity decay product consisting of the
charged helium-4 nucleus (two protons and two neutrons with a positive
ionic charge of two, +2). Alpha particles are relatively heavy (8000
times as heavy as the beta particle) and are quickly absorbed by
surrounding matter. The properties of alpha particles are such that
they are only a health hazard if the emitter is in contact with living
tissue. When outside the body, they do not penetrate the skin and are
stopped by a few centimeters of air. However, when inside the body
(breathed in or ingested), the alpha particle may ionize molecules
within cells or may form ``free radicals'' (an atom or chemical group
that contains an unpaired electron and which is very chemically
reactive), either of which may result in the disruption of normal
cellular metabolism and produce changes that affect cell replication
which may induce cancerous cellular growth.
Bq (becquerel): An alternative unit of radioactivity is the Bq,
which is equal to 1 disintegration per second. One pCi is equal to
0.037 Bq, and one Bq is equal to 27 pCi.
cpm/dpm: Counts per minute divided by radioactive disintegrations
per minute; counting efficiency as determined by the counts per minute
detected relative to the predicted disintegrations per minute in a
well-characterized standard.
Half-life: The time required for one-half of a population of
radioactive isotopes to decay; in the case of radioactive contaminants
dissolved in water, it is the time for the concentration of the
radioactive contaminant to decrease by a factor of two due to
radioactive decay.
Heterotrophic Plate Count: A laboratory procedure for estimating
the total bacterial count in a water sample (or ``bacterial density'').
Individual Risk: The risk to a person from exposure to radon in
water is calculated by multiplying the concentration of radon in the
water (pCi/L) by the unit risk factor (risk per pCi/L) for the exposure
pathway of concern (ingestion, inhalation).
Isotopes: Two or more forms of an atomic element having the same
number of protons, but differing in the number of neutrons. Some
isotopes are stable (not radioactive) and some are radioactive,
depending upon the ratio of neutrons and protons.
Monte Carlo Analysis:: Method of approximating a distribution of
model solutions by sampling from simulated ``random picks'' from
distributions of model input values.
pCi (picocurie):: a unit of radioactivity equal to 0.037
radioactive disintegrations per second.
Percentile: For any set of observations, the ``pth percentile
value'' is the value such that p% of the observations fall below the
pth percentile value and (100-p)% fall above it.
pH: Numerical scale for measuring the relative acidity or basicity
of an aqueous solution; values less than 7 are acidic (becoming
increasingly so as they decrease) and above 7 are basic (becoming
increasing so as they increase).
Radioactivity: The spontaneous disintegration of unstable atomic
nuclei (central core of an atom), resulting in the formation of new
atomic elements (daughter products), which may or may not themselves be
radioactive, and the discharge of alpha particles, beta particles, or
photons (other decay particles are known, but their parent isotopes do
not occur in drinking water).
Removal efficiency: A measure of the ability of a particular water
treatment process to remove a contaminant of interest; defined as the
concentration of the contaminant in the treated water (effluent)
divided by the concentration of the contaminant in the source water
(influent).
WL (working level): Any combination of radioactive chemicals that
result in an emission of 1.3 x 105 MeV of alpha particle
energy. One WL is approximately the total amount of energy released by
the short-lived progeny in equilibrium with 100 pCi of radon.
Working Level Month (WLM): 170 hours of exposure to one Working
Level (WL) of radon progeny.
Unit Risk: The risk from lifetime exposure, via the inhalation and
ingestion exposure routes, to water containing an unit concentration (1
pCi/L) of radon.
XVIII. References
American Society for Testing and Materials. 1992 Annual Book of ASTM
Standards, Standard Test Method for Radon in Drinking Water.
Designation: D 5072-92. Vol. 11.01, Philadelphia, PA. [1992] [ASTM
1992]
American Water Works Association. Water:/Stats: The Water Utility
Database, 1996 Survey: Water Quality, Denver, CO. [1997] [AWWA 1997]
American Water Works Association. Existing Volatile Organic Chemical
Treatment Installations: Design, Operations, and Costs, Report of
the Organic Contaminants Control Committee. Denver, CO. [1991] [AWWA
1990]
American Water Works Association Research Foundation. Assessment of
GAC Absorption for Radon Removal, Denver, CO. [November 1998]
[AWWARF 1998a]
American Water Works Association Research Foundation. Critical
Assessment of Radon Removal Systems for Drinking Water Supplies,
Denver, CO. [December 1998] [AWWARF 1998b]
California Department of Health Services. Letter with Attachment
Regarding Radon Sampling Protocol from Jane Jensen of the CA DHS
Environmental Laboratory Accreditation Program to William Labiosa,
USEPA, Office of Ground Water and Drinking Water, [September 3,
1997] [CA DHS 1997]
Centers for Disease Control. Morbidity and Mortality Weekly Report,
Cigarette smoking among adults--United States 1993. [1995] [CDC
1995]
Cornwell, D.A. Air Stripping and Aeration. In Water Quality and
Treatment, 4th Edition, F. Pointius, ed. American Water Works
Association. McGraw-Hill, Inc. New York, NY. 1990. [Cornwell 1990]
Davis, R.M.S. and Watson, J.E. Jr. The Influence of Radium
Concentration in
[[Page 59360]]
Surrounding Rock on Radon Concentration in Ground Water, University
of North Carolina, Chapel Hill. [March 13, 1989] [Davis and Watson
1989]
Dell'Orco M.J., Chadik, P., Bitton, G., and Neumann, R. Sulfide-
Oxidizing Bacteria: Their Role During Air-Stripping. J. of the
American Water Works Association. (90:107-115). [October 1998]
[Dell'Orco et al. 1998]
Dihm, H. and Carr, F.R. Air Stripping Tower Fouling Control for a
Groundwater Treatment System in Florida. In Air Stripping of
Volatile Organic Contaminant Removal. AWWA. Denver, CO. [1988] [Dihm
and Carr 1988]
Dixon, K. and Lee, R. Radon Survey of the American Water Works
System. In Radon in Ground Water. Barbara Graves, ed. Lewis
Publishers, Inc. Chelsea, MI. [1987] [Dixon and Lee 1987]
Dyksen, J.E., Raczko, R.F., and Cline, G.C. Operating Experiences at
VOC Treatment Facilities. In Proc. of the 1995 AWWA Annual
Conference. Anaheim, CA. [June 1995] [Dyksen et al. 1995]
Ershow, A.G. and Cantor K.P. Total Water and Tapwater Intake in the
United States: Population-based Estimates of Quantities and Sources.
Report prepared under National Cancer Institute Order #263-MD-
810264. [1989] [Ershow and Cantor 1989]
Faust, S.D. and Aly, O.M. Chemistry of Water Treatment. Ann Arbor
Press, Inc. Chelsea, MI. p. 477. [1998] [Faust and Aly 1998]
Federal Register. Vol. 51, No. 189. Water Pollution Control;
National Primary Drinking Water Regulations: Radionuclides, Advance
Notice of Proposed Rulemaking (September 30, 1986), 34836-34862. [51
FR 34836]
Federal Register. Vol.56, No. 138. National Primary Drinking Water
Regulations: Radionuclides, Notice of Proposed Rulemaking (July 18,
1991) 33050-33127. [56 FR 33050]
Federal Register. Vol.62, No. 43. National Primary Drinking Water
Regulations: Analytical Methods for Radionuclides: Final Rule and
Proposed Rule (March 5, 1997) 10168-10175. [62 FR 10168]
Federal Register. Vol 62, No. 60. Guidelines Establishing Test
Procedures for the Analysis of Pollutants and National Primary
Drinking Water Regulations; Flexibility in Existing Test Procedures
and Streamlining Proposal of New Test Procedures: Proposed Rule.
(March 28, 1997) 14976--15049. [62 FR 14976]
Federal Register. Vol 62, No. 151. Withdrawal of the Proposed
National Primary Drinking Water Regulation for Radon-222: Notice of
Withdrawal of Proposed Rule. (August 6, 1997) 42221-42222. [62 FR
42221]
Federal Register. Vol 62, No. 193. Performance Based Measurement
System: Notice of Intent. (October 6, 1997) 52098--52100. [62 FR
52098]
Federal Register. Vol 63, No. 160. National Primary Drinking Water
Regulations: Consumer Confidence Reports. (August 19, 1998) 44511-
44536 [63 FR 44511]
Federal Register. Vol 63, No. 241. National Primary Drinking Water
Regulations: Disinfectants and Disinfection Byproducts; Final Rule.
(December 16, 1998), 69390-69476. [63 FR 69390]
Federal Register. Vol. 64, No. 38. Health Risk Reduction and Cost
Analysis for Radon in Drinking Water: Notice and Request for
Comments and Announcement of Stakeholder Meeting. (February 26,
1999) 9559-9599. [64 FR 9559]
Federal Register. Vol 64, No. 92. National Primary Drinking Water
Regulations: Public Notification Rule. (May 13, 1999) 25964-26001.
[64 FR 25964]
Fisher, E.L., Fuortes, L.J., and Field, R.W. Occupational Exposure
of Water-Plant Operators to High Concentrations of Radon-222 Gas, J.
of Occ. and Env. Med. (38:759-764) [August 1996] [Fishter et al.
1996]
Great Lakes-Upper Mississippi River Board of State Public Health and
Environmental Managers (GLUMRB). Recommended Standards for Water
Works, Health Education Services, Albany, NY. [1997] [GLUMRB 1997]
Hei, T.K., Wu, L-J., Liu, S-X, Vannais, D., Waldren, C.A., and
Radners-Pehrson, G. Mutagenic Effects of a Single and an Exact
Number of Alpha Particles in Mammalian Cells, Proc. Natl. Acad. Sci.
USA (94:3765-3770). [1997] [Hei et al. 1997]
Hess, C.T., Bernhardt, G.P., Amsden, J.J., Mba, J.N., and Jones, R.
Granular Activated Carbon to Remove Radon from Drinking Water.
Draft. University of Maine, Orono, ME. [September, 1998] [Hess et
al. 1998]
International Agency for Research on Cancer, World Health
Organization. Monograph on the Evaluation of Carcinogenic Risks to
Humans, Volume 43: Man-made Mineral Fibers and Radon. [1988] [IARC
1988]
International Council on Radiation Protection. Lung Cancer Risk from
Indoor Exposures to Radon Daughters. ICRP Publication 50. Pergamon
Press, Oxford, U.K. [1987] [ICRP 1987]
Jacobi W, and Eisfeld K. Dose to Tissues and Effective Dose
Equivalent by Inhalation of Radon-222, Radon-220 and Their Short-
lived Daughters. GSF Report S-626. Munich: Gesellschaft fur Strahlen
und Umweltforschung. [1980] [Jacobi and Eisfeld 1980]
Kavanaugh, M.C., and Trussell, R. Design of Aeration Towers to Strip
Volatile Contaminants From Drinking Water. In Air Stripping of
Volatile Organic Contaminant Removal. AWWA. Denver, CO. [1989]
[Kavanaugh and Trussell 1989]
Kinner, N. et al. Radon Removal Techniques for Small Community
Public Water Supplies Prepared Under Cooperative Agreement No. CR
812602-01-0 for Risk Reduction Engineering Laboratory, Office of
Research and Development. Cincinnati, OH. [June 1990] [Kinner, et
al. 1990a]
Kinner, N., et al. Radon Removal Using Point-of-Entry Water
Treatment Techniques. EPA/600/2-90/047, Prepared under Cooperative
Agreement No. CR 812602-01-0 for Risk Reduction Engineering
Laboratory, Office of Research and Development. Cincinnati, OH.
[June 1990] [Kinner, et al. 1990b]
Leggett R.W., and Williams L.R. A Proposed Blood Circulation Model
for Reference Man, Health Phys. (69:187-201). [1995] [Leggett and
Williams 1995]
Miller, R.C., Randers-Pehrson, G., Geard, C.R., Hall, E.J. and
Brenner, D.J. The Oncogenic Transforming Potential of the Passage of
Single Alpha Particles Through Mammalian Cell Nuclei. Proc. Natl.
Acad. Sci. USA, (96:19-22). [1999] [Miller et al. 1999]
National Academy of Sciences. National Research Council. Health Risk
of Radon and Other Internally Deposited Alpha-Emitters: (BEIR IV)
National Academy Press, Washington, DC. [1988] [NAS 1988]
National Academy of Sciences. National Research Council. Comparative
Dosimetry of Radon in Mines and Homes. National Academy Press,
Washington, DC. [1991] [NAS 1991]
National Academy of Sciences. National Research Council. Health
Effects of Exposure to Radon (BEIR VI). National Academy Press,
Washington, DC. [1999] [NAS 1999a]
National Academy of Sciences. Committee on the Risk Assessment of
Exposures to Radon in Drinking Water, Board of Radiation Effects
Research, Commission on Life Sciences, National Research Council.
Risk Assessment of Radon in Drinking Water. National Academy Press,
Washington DC. [1999] [NAS 1999b]
National Council on Radiation Protection and Measurements.
Evaluation of Occupational and Environmental Exposures to Radon and
Radon Daughters in the United States, NCRP Report 78. [1984] [NCRP
1984]
National Environmental Laboratory Accreditation Conference. Summary
of the Proficiency Testing Committee Meeting. 1-9 [January 12-13,
1999] [NELAC 1999]
National Research Council. Safe Water From Every Tap: Improving
Water Service to Small Communities. National Research Council.
National Academy Press, Washington, DC. [1997] [NRC 1997]
Orme-Zavaleta, Jennifer. Toxicological Basis for Drinking Water:
Unreasonable Risk to Health Values, J. of the Am. Col. of Tox.
(11(3):325-329). [1992] [Orme-Zavaleta 1992]
Pennington, J.A. Revision of the Total Diet Study Food List and
Diets, J. Am. Diet. Assoc. (82:166-173). [1983] [Pennington 1983]
Reichelt, A. Radon and Its Decay Products in Water Purification
Plants. Env. Int. (22:S761-S768). [1996] [Reichelt 1996]
Rydell, S., Keene, B., and Lowry, J. Granulated Activated Carbon
Water Treatment and Potential Radiation Hazards. J. NEWWA. 234-248.
[December 1989] [Rydell et al. 1989]
Science Applications International Corporation. Geometrics and
Characteristics of Public Water Systems. Report prepared by Science
Applications International Corporation (SAIC) for the Office of
Ground Water and Drinking Water. [August 15, 1999] [SAIC 1999]
Spencer, C.M., Schock, M.R., Del Toral, M., and Sorg, J.J.
Regulatory Interactions of Concern to Small Water Systems with
Emphasis on Maintaining Optimal Corrosion Control. Paper Presented
at The American Water Works Association Annual Conference. Chicago,
IL. [June 20-24, 1999] [Spencer et al. 1999]
[[Page 59361]]
Standard Method 7500-Rn. Standard Methods for the Examination of
Water and Wastewater. 19th Edition Supplement. Clesceri, L., Eaton,
A. Greenberg, A. and Franson, M., eds. American Public Health
Association, American Water Works Association, and Water Environment
Federation. Washington, DC. [1996] [Standard Methods 1996]
Umphres, M. and Van Wagner, I. An Evaluation of the Secondary
Effects of Air Stripping. Prepared Under Cooperative Agreement CR-
809974 with the U.S. EPA Office of Research and Development. [1986]
[Umphres and Van Wagner 1986]
U.S. Environmental Protection Agency, Office of Radiation Programs.
An Estimation of the Daily Average Food Intake by Age and Sex for
Use in Assessing the Radionuclide Intake of Individuals in the
General Population. EPA 520/1-84-021, Washington, DC [1984] [USEPA
1984]
U.S. Environmental Protection Agency. Office of Air and Radiation. A
Citizen's Guide to Radon: What It Is and What to Do About It? OPA-
86-004. [August 1986] [USEPA 1986]
U.S. Environmental Protection Agency. Two Test Procedures for Radon
in Drinking Water, Inter-laboratory Study. EPA/600/2-87/082. [March
1987] [USEPA 1987]
U. S. Environmental Protection Agency. Preliminary Risk Assessment
for Radon Emissions from Drinking Water Treatment Facilities.
Memorandum from Warren Peters and Christopher Nelson of the Office
of Air Quality Planning and Standards to Stephen Clark of the Office
of Drinking Water [June 28, 1988] [USEPA 1988a]
U. S. Environmental Protection Agency. EPA and Assistant Surgeon
General Call for Radon Home Testing. Environmental News, September
12, 1988. Office of Public Affairs (A-107). [USEPA 1988b]
U.S. Environmental Protection Agency. Guidance in Developing Health
Criteria for Determining Unreasonable Risks to Health. [1990] [USEPA
1990]
U.S. Environmental Protection Agency, Office of Water. Final Draft
of Drinking Water Criteria Document for Radon for Proposed Rule.
[USEPA 1991]
U.S. Environmental Protection Agency, Office of Radiation Programs,
Radon Division. Technical Support Document for the 1992 Citizen's
Guide to Radon. EPA 400-R-92-011 Washington, DC [May 20, 1992]
[USEPA 1992a]
U.S. Environmental Protection Agency. Citizen's Guide to Radon: The
Guide to Protecting Yourself and Your Family from Radon. Second
Edition. EPA 402-K-92-00. [USEPA 1992b]
U.S. Environmental Protection Agency, Office of Radiation Programs.
User's Guide for CAP88-PC, Version 1.0. EPA 402-B-001, Washington,
DC [March 1992] [USEPA 1992c]
U.S. Environmental Protection Agency, Office of Air and Radiation.
Consumer's Guide to Radon Reduction: How to Reduce Radon Levels in
Your Home. EPA 402-K92-003. Washington, DC [August 1992][1992d].
U.S. Environmental Protection Agency. Review of Risk Assessments of
Radon Emissions from Drinking Water Treatment Facilities, Memorandum
from Christopher Nelson, Office of Radiation and Indoor Air to Marc
Parrotta, Office of Drinking Water [January 28, 1993] [USEPA 1993a]
U.S. Environmental Protection Agency, Office of Science and
Technology, Office of Radiation and Indoor Air, Office of Policy,
Planning and Evaluation. Draft Uncertainty Analysis of Risk
Associated with Exposure to Radon in Drinking Water. Washington DC.
[April 30, 1993] [USEPA 1993b]
U.S. Environmental Protection Agency. Radiation Research and Methods
Validation: Annual Report 1992. EPA 600/X-93-030. Washington, DC
[April 1993] [USEPA 1993c]
U.S. Environmental Protection Agency, Office of Water. Report to
Congress. Technical and Economic Capacity of States and Public Water
Systems to Implement Drinking Water Regulations: EPA 810-R-93-001.
[September 1993] [USEPA 1993d]
U.S. Environmental Protection Agency. Packed-Column Air Stripping
Cost Model. Computer Program Code Text. [October 1993] [USEPA 1993e]
U.S. Environmental Protection Agency. Office of Air and Radiation.
Home Buyer's and Seller's Guide to Radon. [March 1993] [USEPA 1993f]
U.S. Environmental Protection Agency, Office of Water. Report to the
United States Congress on Radon in Drinking Water: Multimedia Risk
and Cost Assessment of Radon. EPA 811-R-94-001 Washington, DC [March
1994] [USEPA 1994a]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Suggested Guidelines for Disposal of Drinking Water
Treatment Wastes Containing Radioactivity. Draft. [June 1994] [USEPA
1994b]
U.S. Environmental Protection Agency, Office of Science and
Technology, Office of Radiation and Indoor Air, Office of Policy,
Planning, and Evaluation. Uncertainty Analysis of Risks Associated
with Exposure to Radon in Drinking Water. EPA 822-R-96-005.
Washington, DC. [March 1995] [USEPA 1995]
U.S. Environmental Protection Agency, Office of Research and
Development. Exposure Factors Handbook. Volume III--Activity
Factors. NCEA-W-0005, Washington, DC. [April 1996] [USEPA 1996]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Community Water System Survey. Volume II: Detailed
Survey Results Table and Methodology Report. EPA-815-R-97-001b.
[January 1997] [USEPA 1997a]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Manual for the Certification of Laboratories
Analyzing Drinking Water. EPA 815-B-97-001. [March 1997] [USEPA
1997b]
U.S. Environmental Protection Agency. Tritium in Water Performance
Evaluation Study, A Statistical Evaluation of the August 8, 1997
Data, EPA/600/R-97/097 [September 1997] [USEPA 1997c]
U.S. Environmental Protection Agency. Model Systems Report (Draft).
Prepared by Science Applications International Corporation for the
Office of Ground Water and Drinking Water. [March 1998] [USEPA
1998a]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Information for Small Entity Representatives
Regarding the Radon in Drinking Water Rule, Washington, D.C. [April
1998] [USEPA 1998b]
U.S. Environmental Protection Agency, Small Business Advocacy Review
Panel for the Radon Rule. Final Report of the SBREFA Small Business
Advocacy Review Panel on EPA's Planned Proposed Rule for National
Primary Drinking Water Regulation: Radon, Washington, D.C.
[September 1998] [USEPA 1998c]
U.S. Environmental Protection Agency, Office of Radiation and Indoor
Air. Health Risks from Low-Level Environmental Exposure to
Radionuclides. Federal Guidance Report No. 13. Part I--Interim
Version. EPA 401/R-97-014. Washington, DC. [1998] [USEPA 1998d]
U.S. Environmental Protection Agency. National-Level Affordability
Criteria Under the 1996 Amendments to the Safe Drinking Water Act.
Final Draft Report. Prepared by International Consultants, Inc. for
EPA. [August 19, 1998] [USEPA 1998e]
U.S. Environmental Protection Agency, Office of Water. Variance
Technology Findings for Contaminants Regulated before 1996. EPA 815-
R-98-003. Washington, D.C. [September 1998] [USEPA 1998f]
U.S. Environmental Protection Agency. Cost Evaluation of Small
System Compliance Options: Point-of-Use and Point-of-Entry Treatment
Units. Prepared by the Cadmus Group for EPA. [September 1998] [USEPA
1998g]
U.S. Environmental Protection Agency. Guide for Implementing Phase I
Water Treatment Cost Upgrades. Prepared by Science Applications
International Corporation for EPA. [September 1998] [USEPA 1998h]
U.S. Environmental Protection Agency, Small System Compliance
Technology List for the Non-Microbial Contaminants Regulated Before
1996. EPA 815-R-98-002. [September 1998] [USEPA 1998i]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Evaluation of Full-Scale Treatment Technologies at
Small Drinking Water Systems: Summary of Available Cost and
Performance Data. [December 1998] [USEPA 1998j]
U.S. Environmental Protection Agency. Evaluation of Central
Treatment Options as Small System Treatment Technologies. Prepared
by Science Applications International Corporation for EPA. [January
1999] [USEPA 1999a]
U.S. Environmental Protection Agency, Office of Science and
Technology. Draft Criteria Document for Radon in Drinking Water.
Washington, DC. [July 1999] [USEPA 1999b]
U.S. Environmental Protection Agency. Co-Occurrence of Drinking
Water Contaminants. Primary and Secondary Constituents, with two
sets of appendices:
[[Page 59362]]
Appendices A-D and Appendices E-F (Draft Report). Prepared by
Science Applications International Corporation for EPA. [May 21,
1999] [USEPA 1999c]
U.S. Environmental Protection Agency. Co-Occurrence of Drinking
Water Contaminants: Initial Tables of Statistical Analysis of
Secondary Constituents. Draft Prepared by Science Applications
International Corporation for EPA. [February 2, 1999] [USEPA 1999d]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Drinking Water Baseline Handbook (First Edition).
[March 2, 1999] [USEPA 1999e]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Regulatory Impact Analysis and Revised Health Risk
Reduction and Cost Analysis for Radon in Drinking Water (Draft).
[July 1999] [USEPA 1999f]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Methods Occurrence, and Monitoring Document for
Radon, Draft. [August 6, 1999] [USEPA 1999g]
U.S. Environmental Protection Agency. Technologies and Costs for the
Removal of Radon from Drinking Water. Prepared by SAIC for EPA. [May
1999] [USEPA 1999h]
U.S. Environmental Protection Agency. Technical Notes on Estimating
the Health Risk Reduction from EPA's Indoor Radon Program. Brian
Gregory, Office of Radiation and Indoor Air. Washington, DC. [May
1999] [USEPA 1999i]
U.S. Environmental Protection Agency. Projected National Radon Off-
Gas Emissions and Associated Fatal Cancer Risks for Various Radon
MCL Options. Memorandum from William Labiosa to Sylvia Malm, Office
of Ground Water and Drinking Water, [May 12, 1999] [USEPA 1999j]
U.S. Environmental Protection Agency, Office of Policy. Guidelines
for Preparing Economic Analyses (Draft). [June 11, 1999] [USEPA
1999k]
U.S. Environmental Protection Agency. Issue Paper: Intra System
Variability in Ground Water Radon Levels. Prepared by ICF
Incorporated for EPA, Office of Ground Water and Drinking Water
[August 6, 1999] [USEPA 1999l]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. An Analysis of the Potential Benefits and Costs of
Radon in Drinking Water for Non-Transient, Non-Community Water
Systems (NTNCWS). [August 1999] [USEPA 1999m]
Viscusi, W.K., W.A. Magat, and J. Huber. Pricing Environmental
Health Risks: Survey Assessments of Risk-Risk and Risk-Dollar Trade-
Offs for Chronic Bronchitis. Journal of Environmental Economics and
Management, 21:32-51 [1991] [Viscusi 1991]
Wade Miller Associates, Inc., Occurrence and Exposure Assessment for
Radon in Public Water Supplies, prepared for EPA Office of Drinking
Water [September 25, 1990] [Wade Miller 1990]
Wade Miller Associates, Inc., Addendum to Occurrence and Exposure
Assessment for Radon, Radium 226, Radium 228, Uranium, and Gross
Alpha Particle Activity in Public Water Supplies, (Revised
Occurrence Estimate Based on Comments to the Proposed Radionuclides
Regulations), Final Draft, prepared for EPA Office of Drinking Water
[September 1993] [Wade Miller 1993]
Appendix 1 to the Preamble: What Were the Major Public Comments on
the 1991 NPRM and How Has EPA Addressed Them in This Proposal?
EPA received more than 600 comments on the Notice of Proposed
Rulemaking (NPRM) of July 18, 1991 (56 FR 33050). Of the comments
received, 289 were from public water suppliers, 89 were from
individuals, 76 were from local governments, 52 were from States, 48
were from companies, 43 were from trade/professional organizations,
12 were from Federal agencies, 10 were from health/environmental
organizations, 3 were from Members of Congress, and 2 were from
universities. EPA received additional comments at public hearings on
September 6, 1991, in Washington, DC and on September 12, 1991, in
Chicago, Illinois.
Those commenting raised several concerns, including cost of rule
implementation, especially for small public water systems, and the
larger risk to public health from radon in indoor air from soil
under buildings. The next sections summarize major public comments
on the 1991 NPRM and provide brief responses in the following areas
of most concern: (1) General issues; (2) statutory authority and
requirements; (3) radon occurrence; (4) radon exposure and health
effects; (5) maximum contaminant level; (6) analytical methods; (7)
treatment technologies and costs; and (8) compliance monitoring. In
many instances the following sections refer the reader to applicable
sections in today's preamble where many of the issues have been
fully discussed.
A. General Issues
Additional regulation: Some public comments opposed additional
regulation in general, and additional drinking water regulation in
particular. Some comments also suggested EPA proceed with a more
integrated approach to environmental regulation, i.e., that
mitigation programs be designed to provide control over major
exposure routes, which in the case of radon must take the soil gas
source into account.
EPA Response: At the time of the 1991 proposal, EPA did not have
authority under SDWA for a broader radon rule. However, the SDWA as
amended in 1996 provides such authority. In addition to requiring
EPA to promulgate a regulation for radon in drinking water, the SDWA
radon provision also includes a less stringent alternative maximum
contaminant level (AMCL) and a multimedia approach to address radon
in indoor air. Much of the health threat is associated with radon
emanating from soil gas into indoor air. Risk from drinking water
particularly through the inhalation pathway is also a significant
and preventable risk. Today's proposal addresses all major routes of
exposure and is intended to promote multimedia mitigation (MMM)
programs and implementation of the AMCL. Thus, the Agency expects to
provide more cost-effective reductions in the health risks
associated with radon.
Federal funding for compliance and phased implementation:
Commenters asked the Agency for increased flexibility in complying
with the proposed regulation through phased compliance; cheaper
removal technologies; and/or additional Federal funding. Industry
and other groups also recommended a phased implementation of radon
removal, focusing first on priority water sources with the highest
radon levels.
EPA Response: Today's proposal provides different compliance
dates for compliance with the MCL and with the AMCL/MMM program,
such that there will be sufficient time to implement the MMM
program.
The Agency recognizes that the SDWA regulations will continue to
place a significant burden on some small communities with limited
tax bases and resources with which to attain compliance. The EPA
drinking water State Revolving Fund provides support to the States
and public and private water suppliers, in particular to small
public water suppliers. This fund offers capitalization grants to
the States for low-interest loans to help water systems comply with
the SDWA (For more information refer to Section XIV.C.1 of today's
preamble.)
In addition, EPA surveys of public and private water suppliers
have been initiated to understand more clearly their needs in
particular in terms of funding to support capital improvements in
the context of implementing SDWA-related plans.
B. Statutory Authority and Requirements
Applicability to non-transient, non-community (NTNC) systems:
Ten commenters stated that EPA must provide better justification for
regulating non-transient, non-community water systems along with
community water systems. The indoor occupancy factors and exposure
rates are different for persons in the workplace (i.e., school and
hospital) than in the home. EPA should state clearly how the final
rule will apply to this group.
EPA Response: About one-third of the systems estimated in 1991
as being affected by the final regulation were NTNC water systems.
The Agency requested data in 1991 on NTNC system exposure patterns
but received none; subsequently, the Agency conducted analysis on
limited data on NTNC occurrence and exposure patterns and found the
attendant exposures and risks to be relatively small in comparison
to those estimated for community water supplies. (For more
information refer to Section XI.D of today's preamble.)
In keeping with the flexibility accorded the Agency by SDWA to
focus on areas of cognizable public health risk, EPA proposes that
NTNC water systems not be required to comply with the proposed radon
regulation. At the same time, EPA is soliciting comment and data
related to this issue and has left open its options in terms of the
final radon regulation.
State authority: Commenters felt that the Federal drinking water
regulations should
[[Page 59363]]
not be uniform across the nation's drinking water supply. Many
drinking water issues, including those which involve unique
circumstances in the State and the necessary resources to implement
programs, remain unresolved and perhaps are not resolvable by the
Federal government. As a result, States will need to carry more of
the responsibility in regulating drinking water given their
familiarity with local circumstances.
EPA Response: The Agency acknowledges the unique circumstances
faced by State primacy programs and public water systems. According
to the framework set forth in the SDWA Amendments, States will have
the option of adopting the MCL or the higher AMCL and the MMM
program to address radon in indoor air. State programs in this area
are expected to vary, in part due to radon occurrence patterns
locally and in part due to State resources as they apply to
monitoring public water systems; also States will have flexibility
in MMM program implementation, and through consideration of
variances and exemptions as allowed under SWDA.
C. Radon Occurrence
Radon in PWS (Nationwide): The American Water Works Association
(AWWA) suggested that EPA's 1991 national occurrence estimates for
radon were low compared to actual levels, i.e., greater than 20
percent low, resulting in an inaccurate EPA cost impact estimate.
The Association suggested EPA consider the following changes to the
radon occurrence analysis:
Disaggregation of the National Inorganics and
Radionuclides Survey (NIRS) occurrence data for the smallest public
systems, i.e., those serving fewer than 500 persons, into two
subsets of systems;
An accounting in the radon occurrence analysis for
geologic conditions in various regions by applying NIRS data in an
area-specific manner;
Updating and increasing the inventory (including NTNCs)
based upon FRDS data;
Inclusion of State radon data in the national
occurrence analysis;
EPA analyses may have underestimated radon in water
levels because the location of sampling in NIRS was in the
distribution systems (where natural decay of radon-222 may have been
significant, thereby lowering occurrence estimates).
EPA Response: EPA analyses of these issues addressed the
concerns described previously to the extent feasible (USEPA 1999c).
The EPA analyses have incorporated the referenced issues as data
allowed; the analyses also addressed newer data collected and/or
submitted to EPA.
The Agency used State radon in drinking water data to refine the
previous analysis that were based solely on the NIRS data. The
Agency identified and obtained data from a number of States that
supplement the geographic coverage, representativeness, and utility
of the NIRS data in predicting the occurrence of radon in drinking
water in the U.S. Additional data sets were obtained that, while not
addressing radon distributions in States or regions, provided
significant data related to the sampling, analytical, temporal and
intra-system variability of radon measurements. The data from the
NIRS and from the supplementary data sources were subjected to
extensive statistical analysis to characterize their distribution
and compare data sets.
These analyses are discussed and referenced in today's preamble
Section XI.C. The results indicate that: radon levels seen in the
NIRS data sets were generally slightly lower than those seen in the
wellhead and point-of-entry data provided by the same States (with
radon levels being more comparable in the very small systems due to
short residence times); previous results were verified that radon
levels in the U.S. are the highest in New England, the Appalachian
uplands and other Western and Midwest regions; the levels of radon
seen in the supplemental State data sets were similar to those seen
in the NIRS data for the same regions; and, due to procedures used
to adjust the NIRS data, the proportions of systems exceeding the
various levels in the current study are greater than those seen in
previous analyses.
However, best estimates of the numbers of systems exceeding
regulatory levels in EPA's 1993 estimate for the 1994 EPA Report to
Congress (USEPA 1994) and the central tendency estimates in the
current analysis are quite similar. This is because the total
estimated number of community and non-community non-transient
systems that are believed to be active in the U.S. has decreased
approximately 17 percent between 1993 and the Agency's current
estimates. Part of this difference is due to system consolidation,
and part may be due to improved methods for differentiating active
from inactive systems, although the relative importance of these two
factors is not known.
Occurrence of radon in California: A California drinking water
industry association provided a number of resources including the
following: a survey of its member agencies; a California Department
of Health Services (DHS) Groundwater Study; and the Metropolitan
Water District's (MWD) Southern California Radon Survey. The
commenter produced estimated radon occurrence figures which far
exceeded EPA's California and national occurrence profiles. The
commenter's estimate predicted 75 percent to 97 percent of
California public water systems out of compliance with a radon
standard of 300 pCi/L. The commenter submitted to EPA additional
methods and source data necessary for a complete EPA evaluation of
this comment.
EPA Response: EPA studied the commenter's methodology for
determining radon occurrence in California, proposed water system
categorization scheme, and the sources of radon data (surveys
mentioned previously), and has concluded the following:
That sampling in the California surveys biased the
results towards higher radon levels since data were apparently
collected at the wellhead;
The methods used in combining data sources (and in
substitutions within data sets) resulted in substantial
overestimation of radon occurrence in California ground water
supplies.
The commenter assumed 23 percent more public water
supplies in California than indicated in then-current EPA FRDS
records;
The use of commenter's GIS-predicted radon levels for
California systems was also problematic (USEPA 1999c).
EPA believes that EPA NIRS survey did not under represent the
levels of radon in California. A comparison by EPA of the NIRS-
California data and other California data reveals a similarity in
results. Furthermore, EPA results are more in accord with California
State predictions submitted to EPA during the same comment period.
Variability of radon levels in water: The American Water Works
Service Company (AWWSC) provided technical information on the issue
of radon variability in well water. AWWSC said that the variability
of radon levels in well water is a phenomenon that could affect the
compliance status of systems. AWWA and the Association of California
Water Agencies also echoed concerns about the seasonal and diurnal
variability in groundwater.
EPA Response: EPA analyzed this issue to determine if radon
variability may or may not have any influence on national occurrence
profiles. EPA reviewed the two available sources of information on
radon variability (Kinner et al. 1990), and data supplied by the
American Water Works Service Co. (AWWSC). The Kinner report was
limited to four sites in New Hampshire that exhibited short-term and
long-term variability of radon. The AWWSC data were drawn from 400
wells, nationwide, in 1986 and 1987. Kinner's data appear to
indicate a radon fluctuation of 20 to 50 percent in well water over
long-term intervals, weekly or biweekly. The short-term variability
(15 to 180 minute intervals during a three month test at one site)
showed a fluctuation of 50 percent as observed in the long-term
test. These studies did not try to correlate any of the variability
observed with well yield and water table level to account for the
inconsistent patterns. The data provided were too limited to
independently analyze factors that may have influenced radon level
fluctuations. However, EPA notes that the short-term and long-term
variabilities of radon observed at a single site were similar. This
suggests that the long-term variability may be a reflection of
random sampling where short-term influences are influencing radon
levels.
The AWWSC analysis of radon in well water included sampling in
the fall of 1986 and January 1987. A decrease of 29 percent on
average was found over the two-month period. A change in analytical
procedure accounted for about 10 percent of that difference. The
remaining 19 percent difference was not explained. AWWSC also
conducted a test of the effect of pumping time on radon levels over
a short period (five days then two days), beginning with an idle
period. AWWSC inferred that an observed initial increase in radon
level (about 25 percent) was due to radon decay in water that had
been sitting near the well casing. According to AWWSC, a subsequent
decrease (much smaller) over two days was due to the drawing of less
enriched water from beyond a potential geologic radon source yet
within the cone of depression.
[[Page 59364]]
EPA believes that local geologic and operating conditions may
produce temporal variations in radon levels in ground water sources.
However, data are too limited to permit drawing of any conclusions.
Also, since the Kinner and AWWSC reports cited water that generally
contained radon in the high levels, 2,500 to 200,000 pCi/L, and
1,200 to 1,700 pCi/L, respectively, EPA cannot draw any conclusions
on the effect(s) of short or long-term variability on radon in water
at 300 pCi/L. Because EPA NIRS data represents single, one-time
values for systems sampled, it produces no basis for a bias
conclusion (i.e., over- or under-estimates). On the contrary, the
random nature of the NIRS survey would cancel any differences
between the NIRS level and the ``true average'' radon level in
public supplies.
Radon Emanation from Pipe Scale Deposits: Data received after
the comment period, and subsequently reviewed by EPA, suggested that
due to an existing radon source (radium-226) in some systems, levels
of radon-222 may in some instances increase as water passes through
water distribution systems.
EPA Response: A paper by Valentine et al. (Valentine 1992)
contained data on the phenomenon of radon levels increasing in water
distribution pipelines. In three of five distribution systems
studied in Iowa, the paper's authors found what they refer to as
radon ``hot spots.'' These systems have more radon in delivered
water than at the entry to distribution. However, more
geographically diverse data generally show that natural radon decay
is a more influential factor as water is distributed. In other
words, without nationally-relevant data to the contrary, it would be
expected that within-distribution system radon decay supercedes
radon production, except in very specific circumstances.
A more recent article by Field et al. (1995) reported that a
case study of an Iowa water system with an average of 2.2 mg/L
dissolved iron and 2.5 pCi/L of radium-226. The finished water
entering the distribution system had a mean radon level of 432
54 pCi/L (one standard deviation). Field et al.
measured radon levels at the taps of 25 homes and measured radon
levels ranging from 81 pCi/L to 2,675 pCi/L, with a mean of 1,108
648 pCi/L. The authors concluded that iron scale
deposits were sorbing radium-226, the parent of radon-222. In the
case study reported, greater than 80% of the surface pipe-scale was
comprised by iron oxides, with traces of scales containing calcium
and silicon. Since iron oxides have been shown to selectively
scavenge radium, it is plausible that a co-occurrence of high iron
and radium levels may result in the production of significant levels
of radon within the distribution system. Other factors that would
determine the level of radon produced include concentration of
radium-226 sorbed to the pipe scale, the quantity, distribution, and
surface area of the scale, the composition of the scale, all of
which are determined by the average finished water quality, and the
length of time the water is in contact with the scale. All case
studies were confined to the state of Iowa.
It remains to be shown that the confluence of conditions that
result in significant radon production within distribution systems
exists commonly at the national level or is confined to specific
locales (e.g., areas with high average levels of iron, radium-226,
and other site-specific factors).
Regarding this issue, information available at the present time
does not support a determination as to the extent to which this
phenomenon may occur in the U.S. The Agency is, however, soliciting
comments in today's proposal on the advisability of requiring
additional monitoring for radon as a source of consumer exposure
from the distribution system, and on other radon occurrence issues.
D. Radon Exposure and Health Effects
Approximately 400 public comments were submitted on the
assessments of exposure to and health effects of radon in the 1991
NPRM. The major issues raised in these comments, including comments
regarding the proposed MCLG, are addressed next.
Linear no-threshold dose response model: Many commenters were
concerned that EPA only used a linear no-threshold dose-response
model in projecting cancer risk associated with low level exposure
to radon in the domestic environment.
EPA Response: The shape of the dose-response curve for radon has
been evaluated in detail by the NAS (1999a, 1999b), who concluded
that essentially all available data are consistent with a linear
non-threshold mechanism. This includes data on the effects of a wide
range of ionizing radiation, as well as direct dose-response
relationships observed for radon in animals studies and in studies
of cohorts of underground miners. The EPA concurs with the NAS
evaluation and conclusion.
Age dependence on risk from radon exposure: A few commenters
stated that EPA should consider the effect of exposure at young
ages. According to these commenters, the additional risks in
children were not well addressed.
EPA Response: Data on the relative sensitivity of children to
radon are sparse. In general, the NAS Radon in Drinking Water
Committee concluded that there is insufficient scientific
information to permit quantitative evaluation of the risks of lung
cancer death from inhalation exposure to radon progeny in
susceptible sub-populations such as infants, children, pregnant
women, and elderly and seriously ill persons. However, the BEIR VI
committee (NAS 1999a) noted that there is one study (tin miners in
China) that provides data on whether risks from radon progeny are
different for children, adolescents, and adults. Based on this
study, the committee concluded that there was no clear indication of
an effect of age at exposure, and the committee made no adjustments
in the model for exposures received at early ages. This indicates
that children are not an especially susceptible sub-group. With
respect to cancer risk from ingestion of radon, NAS (1999b)
performed an analysis to investigate the relative contribution of
radon ingestion as a child to the total risk. This analysis
considered the age dependence of water consumption, of the behavior
of radon and its decay products in the body, of organ size, and of
risk. The results indicated that dose coefficients are somewhat
higher in younger people than adults. NAS (1999b) estimated that
about 30 percent of a lifetime risk was due to exposures occurring
during the first 10 years of life.
Uncertainty of radon risk estimates: Several commenters said EPA
needs to provide a more in-depth discussion of the uncertainty
associated with the risk estimates for radon.
EPA Response: EPA has performed a very detailed two-dimensional
Monte Carlo evaluation of variability and uncertainty in exposure
and risk from water-borne radon (USEPA 1993, 1995). The methods and
inputs used by EPA were reviewed by the SAB and by NAS, and the
results were judged to be appropriate and sound, subject to some
refinements in the uncertainty bounds on some of the inputs. Based
on the most recent recommendations from the NAS regarding the
uncertainty in the risk coefficient for ingestion and inhalation
exposure, EPA (1999d) has recalculated the uncertainty bounds around
each risk estimate. In brief, the credible interval around the best
estimate of individual and population risks from inhalation and
ingestion exposure pathways are about four-fold and fourteen-fold,
respectively.
Extrapolation of high dose in mines to lower dose in homes: Many
commenters stated that the differences in dose between the mines and
homes in the 1991 NAS report Comparative Dosimetry of Radon in Mines
and Homes needs to be incorporated into the Agency's radon progeny
inhalation risk calculation.
EPA Response: EPA and NAS both recognize the importance of
potential differences between dose and risk per unit exposure in
mines and in homes. The ratio of the dose to lung cells per WLM in
the home compared to that in a mine is described by the K factor.
Based on the best data available at the time, NAS (1991) had
previously concluded that the dose to target cells in the lung was
typically about 30 percent lower for a residential exposure compared
to an equal WLM exposure in mines (i.e., K=0.7). The BEIR VI
committee re-examined the issue of the relative dosimetry in homes
and mines. In light of new information regarding exposure conditions
in home and mine environments, the committee concluded that, when
all factors are taken into account, the dose per WLM is nearly the
same in the two environments (i.e., a best estimate for the K-factor
is about 1) (NAS 1999a). The major factor contributing to the change
was a downward revision in breathing rates for miners. Thus, NAS has
concluded that the risk coefficient based on miners is appropriate
for use in residences without adjustment.
Possible confounding factors in mine studies: Some commenters
raised questions about the possible confounding factors in the miner
epidemiological studies EPA used to project lung cancer risks.
Commenters stated that, besides radon, exposure to other
contaminants not found at home can produce synergistic effects. Such
other contaminants could include diesel fumes, excessive dust
[[Page 59365]]
(which may be a problem in poorly constructed mines without adequate
ventilation), and other radionuclides like uranium in the mine air.
EPA Response: The effects on radon risk estimates from
potentially toxic exposures to substances such as silica, uranium
dust, blasting fumes, and engine exhaust to underground miner
cohorts were carefully examined in the NAS reports on radon risks
(NAS 1988, 1999a) and other studies. For example, in the Malmberget
iron miner study, Radford and St. Clair Renard (1984) investigated
and determined that the risk from confounders such as tuberculosis,
dust, silica, diesel exhaust, metals and asbestos is negligible.
Edling and Axelson (1983) found the Grangeberg mine atmosphere clean
of arsenic, asbestos and carcinogenic metals. In the Eldorado miner
cohort (NAS 1988), potential confounders were investigated and
exposures to silica and diesel exhaust were very low. In the
Czechoslovakian uranium miners' study, Sevc et al. (1984, 1988)
found that cigarette smoking was the only risk factor other than
radon that was a significant exogenic carcinogenic agent. Two of the
studies (China and Ontario) have quantitative data on arsenic, and
there was no significant variation in excess relative risk per unit
radon exposure across different levels of arsenic exposure (NAS
1999a). Despite the variety of exposures to potentially toxic agents
other than radon, the dose-response between radon and lung cancer
death was approximately consistent across the mining cohorts. NAS
(1988) also noted that animal studies show no evidence of a
synergistic effect of these agents on lung cancer risk from radon.
Taken together, these findings indicate that the effect of
confounding factors on observed lung cancer rates in miners is
likely to be small.
Radon-smoking interaction: Several commenters stated that EPA's
analysis shows that smoking acts synergistically with radon to
induce lung cancer. The risk from radon is, on average, ten times
higher for smokers than for the rest of the population, and over 20
times higher for heavy smokers. Several commenters asked why they
should spend resources to remove a natural contaminant from water
while more than \2/3\ of the related cancer risk is attributable to
the subpopulation who smoke.
EPA Response: Because of the strong influence of smoking on the
risk from radon, the BEIR VI committee (NAS 1999a) evaluated risk to
ever-smokers and never-smokers separately. The BEIR VI committee had
smoking information on five of the miner cohorts, from which they
concluded that there was a submultiplicative interaction between
radon and smoking in causing lung cancer. Based on current smoking
prevalence rates, it is estimated that about 84 percent of all
radon-induced lung cancers will occur in ever-smokers, with only 16
percent in never-smokers. Thus, it is true that a reduction in radon
exposure will save more cancer cases in the cohort of smokers than
nonsmokers, but the relative amount of risk reduction is actually
greater for nonsmokers than smokers.
Epidemiological studies of lung cancer in the home environment.
Some commenters stated that in estimating risk associated with
exposure to radon, EPA should consider health risk data associated
with the exposure to low levels of radon in the domestic
environment.
EPA Response: The NAS (1999a) has recently performed a careful
analysis of epidemiological data on the risk of cancer in residents
from radon. The NAS committee concluded that because of numerous
design and experimental limitations, these studies do not constitute
an adequate data base from which quantitative risk estimates can be
derived. However, the data from studies in residents are considered
to be generally consistent with the predictions based on the miner
data.
Lack of experimental or epidemiological data link exposure via
ingestion to increased cancer rates: Several commenters stated that
no experimental or epidemiologic data link exposure via ingestion to
increased cancer rates. The basis for ingestion risk data was a
surrogate gas, xenon-133, that behaves similarly to radon.
EPA Response: Although no human or animal data directly
demonstrate cancer risk from ingestion of radon, it is certain that
ingested radon is absorbed from the gastrointestinal tract into the
body, that this absorbed radon is distributed to internal tissues
which are then irradiated with alpha particles as the radon and its
progeny undergo decay. That alpha irradiation increases cancer risk
is well established (UNSCEAR 1988; NAS 1990).
EPA's ingestion risk estimate is based on the conclusions from
the NAS Radon in Drinking Water committee (NAS 1999b). The NAS
committee performed a re-evaluation of the risks from ingestion of
radon in direct tap water using the basic approach described in
Federal Guidance Document 13 (USEPA 1998). This involved developing
a new pharmacokinetic model of the behavior of ingested radon, based
primarily on observations of the behavior of ingested radon in
humans, as well as studies using xenon and other noble gases. NAS
also addressed the uncertainties (within an order of magnitude) of
the risk estimates for oral exposure associated with dose estimate
to the stomach and in the epidemiologic data used to estimate the
risk (NAS 1999b). Because the magnitude of the risk posed by
ingestion is about 10 percent of the risk from inhalation of radon
progeny, these uncertainties are not most critical in evaluating the
overall hazards from water-borne radon.
Air-water transfer factor and episodic exposure: As for
inhalation exposure, most commenters supported EPA's proposed radon
water-to-air transfer ratio of 10,000:1. Two commenters regarded
this transfer factor as too conservative.
EPA Response: EPA has performed a detailed evaluation of radon
gas transfer from water to air (USEPA 1993, 1995). Values are highly
variable between buildings, with an average value of about 1E-04.
The NAS has recently performed an independent review of both
measured and modeled values, and the NAS committee also concluded
that a value of 1E-04 is the best point estimate available (NAS
1999b).
Outdoor versus indoor radon concentrations: Some commenters
asserted that the concentration of radon in outdoor air is higher
than the indoor air concentration resulting from the proposed MCL of
300
pCi/L.
EPA Response: EPA agrees. The NAS committee reviewed all the
ambient radon concentration data that are available, and based on
these data concluded that the best estimate of the average ambient
(outdoor) radon concentration in the United States is 0.4 pCi/L of
air. In contrast, based on a transfer factor of 1 x 10-4,
the contribution to indoor air from an average radon concentration
in water (about 213 pCi/L) is only about 0.021 pCi/L. However, some
groundwater systems have much higher radon concentrations, and
increments in indoor air from water-borne radon may be much higher
in those cases. As required by the Congress. EPA is implementing the
MMM program to address the issue of relative radon risk from water
and air.
Direct tap water ingestion rate: Concerning ingestion intake,
few commenters expressed an opinion on the direct tap water
ingestion rate of 1 L/day. One commenter suggested that the intake
assumption should be 0.7 L/day, and another, 0.25 L/day.
EPA Response: EPA has based its current assessment of this issue
on reports by the National Academy of Sciences and others. The
reader is referred to a fuller discussion in the preamble to today's
proposed radon in drinking water regulation and to references cited
therein (see Section XII).
Radon loss via volatilization prior to ingestion: Two commenters
felt that the 20 percent radon loss from direct tap water before
ingestion is conservative.
EPA Response: Data are limited on the amount of radon lost from
direct tap water before ingestion. Several studies (von Doblin and
Lindell 1964; Hursh 1965; Suomela and Kahlos 1972; Gesell and
Prichard 1980; Horton 1982) suggest a value of about 20 percent as
the central estimate of radon lost before direct ingestion. Because
of the lack of data, the NAS (1999b) recommended that a value of 0
percent (i.e., no loss) be assumed. It is important to note that
this applies only to ``direct tap water'', and that radon loss is
assumed to be nearly complete from other types of water (coffee,
juice, that in foods, etc.).
Concerning the potential additional loss from the stomach prior
to absorption, EPA believes that radon does not escape from the
esophagus. An available study (Correia et al. 1987) conducted by the
Massachusetts General Hospital specifically measured exhaled air
following ingestion of radioactive xenon in drinking water. Gas did
not immediately escape through the mouth. However, the absorption
through the stomach and small intestine transferred xenon to the
bloodstream and lungs. The pharmacokinetic model used to evaluate
risk from ingested radon utilizes this absorption mechanism.
New studies indicating reduced lung cancer risk: Some commenters
asserted that the lung cancer risk estimates will be reduced based
on new studies.
EPA Response: The risk coefficients for lung cancer derived by
NAS (1999a, 1999b) are based on a detailed analysis of all of the
currently available studies.
[[Page 59366]]
Relative risk of radon from soil versus radon from drinking
water: Many commenters stated that the risks posed by radon in water
are small compared to the risk of radon from soil, and that
regulation of radon in water will have very little effect in
reducing the total risk of cancer from radon exposure.
EPA Response: EPA recognizes that the risk to residents
contributed by radon in household water is a relatively small
fraction of the risk contributed by radon released into indoor air
from soil. Based on the most recent quantitative analysis, NAS
estimates that this fraction is only about 1 percent. Nevertheless,
it is still true that radon in water is one of the most hazardous
substances in public water systems, contributing a total of about
160-170 cancer deaths per year. Thus, regulation of radon in water
is appropriate.
Cancer risk posed by radon in drinking water: Radon in drinking
water is one of the water contaminants with the highest estimated
cancer risk.
EPA Response: EPA agrees, and it is for this reason that EPA
believes that regulation of radon in water is necessary and
appropriate. By definition, because radon is a known human
carcinogen, the MCLG is zero.
E. Maximum Contaminant Level
Opposition to a radon MCL of 300 pCi/L: More than 300 commenters
representing trade associations, Federal and State agencies, and
regional and community water suppliers disagreed with a standard of
300 pCi/L for radon in drinking water. The strongest opposition came
from California, Nebraska, and the northeastern region of the United
States. Other commenters suggested the MCL be set at 1,000 pCi/L or
at 2,000 pCi/L.
EPA Response: As referenced in Section A of this Appendix, the
SDWA as amended in 1996 provides EPA authority to utilize an
alternative approach (AMCL with MMM programs), which is expected to
significantly allay concerns of stakeholders and commenters on the
1991 proposal.
Use of cost-effectiveness in standard setting: Local water
agencies throughout California and elsewhere in the United States
insisted that water rates would double, resulting in economic
problems. State and local water agencies were in almost unanimous
agreement that the proposed standard may not be cost-effective,
posing significant financial and administrative burdens on agencies
and customers.
EPA Response: In the past, EPA generally limited consideration
of economic costs under the SDWA to whether a treatment technology
was affordable for large public water systems. Under the SDWA as
amended in 1996, the Agency has conducted considerable analysis in
the areas of cost and technologies for small systems implementing
the radon MCL and on small system compliance technologies. (For more
information on related EPA analyses refer to today's proposal.)
The MCL as proposed in 1991 and in today's action was set within
the EPA regulatory target range of approximately 10-4 to
10-6 individual lifetime fatal cancer risk level, to
ensure the health and safety of the country's drinking water supply.
Although this level will prevent numerous fatal cancer cases per
year, the Agency recognizes that this benefit would affect only
radon in ground water or 5 percent of the total radon exposure. The
Agency expects the proposed AMCL/ multimedia approach will result in
greater radon risk reduction at lower cost. (The multimedia
mitigation program and the projected costs and benefits are
described in greater detail in today's proposal.)
Impact on private wells: Several commenters expressed concern
over the potential impact of the proposed standards on private
wells.
EPA Response: The Agency cannot comment on the impact of an
NPDWR (radon standard) on private wells. EPA currently possesses
some data from State surveys that indicate relatively high levels of
radon in private wells. However, the data are distinct from Public
Water System data collected by EPA and others. The statute regulates
public water systems that provide piped water for human consumption
to at least 15 service connections or that serve an average of at
least 25 people for at least 60 days each year. Public water systems
can be community; non-transient, non-community; or transient non-
community systems. As a supplement to Federal coverage, some States
extend their authority by regulating systems serving 10 people or
fewer.
F. Analytical Methods
Availability of qualified laboratories and personnel: Commenters
stressed the impact the proposed regulation may have on requirements
for analytical laboratory certification and training of laboratory
technicians. For example, one State wrote that it has no
certification process through which laboratories can receive State
certification for radionuclide analyses. Another commenter stressed
the need for a strategy to work with individual States to ensure
sufficient certified analytical laboratory capacity.
EPA Response: The current situation and expected changes in the
processes governing laboratory approval and certification are
discussed in some detail in today's preamble (Section VIII.B). One
of the changes since 1991 is the formation of the National
Environmental Laboratory Accreditation Conference (NELAC) in 1995.
NELAC serves as a voluntary national standards-setting body for
environmental laboratory accreditation, and includes members from
both state and Federal regulatory and non-regulatory programs having
environmental laboratory oversight, certification, or accreditation
functions. The members of NELAC meet bi-annually to develop
consensus standards through its committee structure. These consensus
standards are adopted by participants for use in their own programs
in order to achieve a uniform national program in which
environmental testing laboratories will be able to receive one
annual accreditation that is accepted nationwide. The intent of the
NELAC standards setting process is to ensure that the needs of EPA
and State regulatory programs are satisfied in the context of a
uniform national laboratory accreditation program. EPA shares
NELAC's goal of encouraging uniformity in standards between primacy
States regarding laboratory proficiency testing and accreditation.
Four-day holding period between sampling and analysis: Several
commenters contended that for laboratories to cope with the
increased number of samples, the holding period should increase to
eight days. A State agency suggested a holding period of seven days.
Another commenter stated that the proposed four-day holding period
was not possible because many ground water systems have sources
distributed over large areas that may need sampling. Certified
personnel will collect, record, package, and send the samples to
analytical laboratories within four days. Also, with a 100-minute
counting time requirement, commercial laboratories may be ill-
equipped to analyze samples from 28,000 systems. Another State
commented that the four-day holding period was not compatible with a
standard work week.
Response: Standard Method 7500-Rn reports a 50 minute counting
time (not 100 minutes) and a four day sample holding time. This
combination of counting time and holding time has been determined to
be a good trade-off, given the limitation of the 3.8 day half-life
of radon. Doubling the sample holding time (i.e., eight days) would
approximately triple the counting time (i.e., to 150 minutes)
necessary to achieve the same level of certainty in the analytical
results, which would probably result in much higher analytical
costs. Since the sample counting procedure is capable of being
highly automated, EPA believes that certified laboratories will be
able to process the required samples with a four-day holding time.
As an example, one laboratory contacted by EPA currently analyzes
radon in 12,000 water samples per year as part of a ground water
monitoring study, providing evidence that a demand for radon
analytical capacity will result in the required laboratory capacity.
Based on an evaluation of the potential for laboratory
certification, performance testing, and analytical procedures, which
included input from stakeholders, the four day holding time has been
determined to be feasible, and should result in lower analytical
costs than a longer holding time and a longer counting time.
Proposed analytical techniques: A commenter representing a group
of utilities approved of direct, low-volume liquid scintillation for
measurement of radon as proposed, but recommended the use of Lucas
Cell de-emanation for measurement of Ra-226 (not also for radon, as
proposed). According to this commenter, the liquid scintillation
method for radon measurement is straightforward and efficient
compared with the Lucas Cell method that requires a high degree of
specialized skill. Also, equipment cost for the Lucas Cell method
may be prohibitive. The Conference of Radiation Control Program
Directors stated that liquid scintillation, while able to detect
radon in water at low levels, may provide laboratory results that
are not reliable.
EPA Response: EPA agrees that LSC has the stated advantages
relative to de-
[[Page 59367]]
emanation. EPA also expects that the vast majority of nationwide
radon analysis will be done using LSC. However, some laboratories
are already equipped to perform the de-emanation method. Since the
de-emanation method performs acceptably well, there is no reason to
refuse the possibility of the added laboratory capacity afforded by
the approval of this method.
Precision variability: A local water agency and an engineering
company representative stated that the 30% precision variability is
inadequate for determining compliance because of the extensive
natural variability in radon levels over time. The combination of
counting error, sampling error, and holding time variability demands
a precision of 20%, which would lead to more consistent
data.
EPA Response: EPA agrees that the 1991 proposal of an acceptance
level of 30%, based on a radon ``practical quantitation
level'' (PQL) of 300 pCi/L is not supportable. This conclusion is
based on an extensive collaborative study of the liquid
scintillation method and the de-emanation method for radon published
by EPA in 1993, as described in the methods section (VIII.b) of the
preamble to this proposal. Today's proposal contains several options
for ensuring that compliance monitoring is performed using radon
methods with acceptable accuracy and precision. Based on other
comments to the 1991 radionuclides proposal, EPA's preferred option
is that the method detection limit (MDL) be used as the measure of
sensitivity for radon, and not a PQL, consistent with the use of the
MDL as the basis for sensitivity in the current radionuclides rule.
EPA is proposing a value of 12 12 pCi/L as the MDL for
radon.
Based on the collaborative study data, EPA's best recommendation
for acceptance limits for performance evaluations is 5%
for single measurements, and for triplicate measurements,
6% at the 95% confidence level, and 9% at
the 99% confidence level.
G. Treatment Technologies and Cost
Water Treatment Costs: Industry groups and several utilities
provided detailed analyses of unit treatment costs for removal of
radon in water. Water treatment cost estimates prepared by a
consultant were up to five times the costs estimated by EPA. An
analysis produced by a consultant showed that among the different
factors influencing annual compliance costs estimated by them, unit
treatment costs have the largest impact.
EPA Response: EPA disagrees that its radon aeration treatment
estimates supporting the 1991 radionuclides proposal were under-
estimates. EPA analyzed the aeration cost model and the cost
elements put forward by the industry commenters and summarized the
major differences between the EPA and industry models. This summary
may be obtained from the docket supporting today's proposal (USEPA
1992). While this summary accounts for the differences in cost
estimates between EPA and the industry and utility estimates, it is
not necessary to go into detail regarding these differences since
overwhelming evidence suggests that EPA's 1992 cost estimates were
much closer to actual unit costs, based on costs reported in case
studies collected since 1991 (USEPA 1999a, AWWARF 1998a) than the
commenter's estimates. A comparison of EPA's current unit capital
cost estimates to actual capital costs reported in published case
studies can be found in Figure VIII.A.1 of this preamble. The
consultant's 1991 estimates are compared against case studies and
against EPA's current estimates in an EPA memorandum dated July 28,
1999 (USEPA 1999b). In summary, the consultant's estimates over-
estimated the small systems case studies by factors ranging from
three for small systems with design flows of around 1 MGD down to
around 0.3 MGD. For the smallest systems case studies (systems
serving around 0.015 MGD), the consultant's estimates were high by a
factor of more than twenty. For large systems, the consultant's
estimates were two to three times higher than the best fit for the
large system case studies. As can be seen in Figure VIII.A.1
(``Total Capital Costs: Aeration Cost Case Studies''), EPA's current
unit capital cost estimates appear to be very conservative compared
to small systems case studies (systems with design flows less than 1
MGD) and are typical of case studies for larger flows (design flows
greater than 1 MGD). It should be noted the costs reported for these
case studies are total capital costs and include all process costs,
as well as pre- and post-treatment capital costs, land, buildings,
and permits. Figures VIII.A.1 through VIII.A.3 shown in the preamble
provide strong evidence that EPA's assumptions affecting its unit
cost estimates are realistic for large systems and are conservative
for small systems.
Additional Treatment--Disinfection: Commenters asserted that
some systems may need to add disinfection treatment to protect
aerated water supplies from biological contamination. It was also
stated that about 58 percent of small systems and 12 percent of
large systems may need to add disinfection technology.
EPA Response: The current cost analysis assumes that all systems
adding aeration and GAC will disinfect. For those systems not
already disinfecting (proportions estimated from the EPA 1997
Community Water System Survey), it was assumed that systems adding
treatment would also add disinfection.
Pretreatment for Iron and Manganese: A commenter also challenged
EPA's position on the minimal pretreatment of a ground water supply
before air stripping of radon. The commenter presumed that iron and
manganese fouling will require additional treatment. While the
comment did not address the costs to pre-treat water for iron and
manganese removal, it was mentioned this pretreatment would result
in high potential costs to water systems.
EPA Response: EPA has re-evaluated its assumptions regarding
iron and manganese (Fe/Mn) fouling and has included costs for
chemical stabilization (sequestration) of Fe/Mn for 25% of small
systems and 15% of large systems. Based on an analysis of the
occurrence of Fe/Mn in raw and finished ground water, EPA believes
that this is adequate to account for Fe/Mn control. Data sources for
this evaluation were: ``National Inorganics and Radionuclides
Survey'' (NIRS); American Water Works Association, ``Water:/Stats,
1996 Survey: Water Quality''. and U.S. Geological Survey, ``National
Water Information System''). This analysis is more fully discussed
in Section VIII of the preamble. EPA reiterates that if its Fe/Mn
cost assumptions were invalid, this fact would be demonstrated in
comparisons of its estimates of capital and O&M costs against those
reported in the case studies cited in the preamble. As described
previously, EPA's unit cost estimates are apparently conservative
for small systems and seem to be typical of large systems.
Aeration as BAT and Use of Carbon Treatment: A major commenter
and a city in California asserted that aeration treatment for radon
could potentially create a problem in air emissions permitting.
Also, a major commenter commented that systems with high radon
levels in water could produce high levels of radon in off-gas,
potentially creating a shift among utilities to activated carbon
treatment and waste (radioactive) disposal problems.
EPA Response: EPA discusses this concern in some detail in
Section VIII of the preamble, including an evaluation of the
estimates of the potential risks. Results from a survey of nine
California air permitting agencies regarding permitting requirements
and costs for radon treatment is also described in the preamble. The
full text of this survey is reported in EPA 1999a.
Centralized Treatment Assumption: Commenters from the regulated
community challenged EPA's cost analysis assumption involving
centralized water treatment for radon. These associations cited the
then-current EPA Community Water Supply Survey of 1986 and the then-
current Water Industry Database. They suggested centralized
treatment facilities were unrealistic and under predicts the costs
to public water systems. The industry asserted that the number of
wells and well groupings per system (with numbers increasing with
increasing system size) will likely determine the number of
treatment sites. An industry group produced estimated distributions
of the percent of systems that would require treatment sites.
EPA Response: Centralized treatment was not assumed in the
current radon cost analysis. EPA's current estimate of national
compliance costs for the proposed radon rule uses the distribution
of wells (treatment sites) per ground water system as a function of
water system size from the 1997 Community Water System Survey (USEPA
1997). EPA assumed that a given system's total flow would be evenly
distributed between the total number of wells at the system. To
estimate the radon occurrence at a particular well within a system
with multiple wells, EPA used its evaluation of intra-system
occurrence variability (the variability of radon occurrence between
wells within a given system) to estimate individual well radon
levels. If multiple wells were predicted to be impacted at a given
system, the cost model assumes that treatment is installed at each
well requiring treatment.
Integrated approach to waste management: Three commenters
declared that compliance with the radionuclides rule will create
radioactive waste that may or may not be
[[Page 59368]]
disposable. They recommended an integrated environmental management
approach in addressing this waste issue.
EPA Response: The Agency used an integrated environmental
management approach to determine BAT in removing contaminants from
drinking water. While Packed Tower Aeration (PTA), the BAT for
radon, does not generate waste requiring disposal, granular
activated carbon is of concern. While not BAT, granular activated
carbon may be used by very small systems to remove radon. Waste
disposal issues regarding GAC treatment for radon are discussed in
some detail in Section VIII of this preamble. For more information,
see NAS 1999b and AWWARF 1998a and AWWARF 1998b.
H. Compliance Monitoring
Sampling location: Four State environmental/health agencies, one
private non-environmental firm, eight public water suppliers, and
one water association suggested that radon sampling of the
distribution system at the point of entry does not allow systems to
account for decay and aeration of radon during distribution.
According to these commenters, sampling is more effective closer to
the point of use.
EPA Response: EPA's proposal requires sampling at the entry
points to the distribution system to assure compliance with the MCL
for the water delivered to every customer. All samples will be
required to be finished water, as it enters the distribution system
after any treatment and storage. This approach allows systems to
account for the decay and aeration of radon during treatment and
storage before it enters the distribution system and at the same
time offers maximum protection to the consumer. It is expected that
radon levels would progressively decrease within the distribution
system, downstream from the point of entry. Therefore, consumers who
are located closest to the point of entry are exposed to higher
levels of radon that those further downstream. In order to assure
maximum protection to all of the consumers, EPA requires sampling at
the entry points to the distribution system.
Compliance period: Clarification concerning the frequency of
compliance periods, specifically in regards to the specific timing
for the commencement of water systems monitoring is warranted.
EPA Response: The proposed monitoring requirements for radon are
consistent with the monitoring requirements for regulated drinking
water contaminants, as described in the Standardized Monitoring
Framework (SMF) promulgated by EPA under the Phase II Rule of the
National Primary Drinking Water Regulations (NPDWR) and revised
under Phases IIB and V. The goal of the SMF is to streamline the
drinking water monitoring requirements by standardizing them within
contaminant groups and by synchronizing monitoring schedules across
contaminant groups.
Systems already on-line must begin initial monitoring for
compliance with the MCL/AMCL by the compliance dates specified in
the rule (i.e., 3 years after the date of promulgation or 4.5 years
after the date of promulgation). New sources connected on-line must
satisfy initial monitoring requirements.
Initial compliance with the MCL/AMCL will be determined based on
an average of 4 quarterly samples taken at individual sampling
points in the initial year of monitoring. Systems with averages
exceeding the MCL/AMCL at any well or sampling point will be deemed
to be out of compliance. Systems exceeding the MCL/AMCL will be
required to monitor quarterly until the average of 4 consecutive
samples are less than the MCL/AMCL. Systems will then be allowed to
collect one sample annually if the average from four consecutive
quarterly samples is less than the MCL/AMCL and if the State
determines that the system is reliably and consistently below MCL/
AMCL.
Systems that primarily use surface water, supplemented with
ground water: One water association suggested that public water
systems supplementing their surface water supply with ground water
are not in violation. Since the actual lifetime risk involved is
significantly lower than those systems using 100 percent ground
water supply, an equitable method of compliance for this type of
combined systems should be administered.
EPA Response: In today's proposal, systems relying exclusively
on surface water as their water source are not required to sample
for radon. Systems that rely in part on ground water during low-flow
periods about one quarter of the year are considered public ground
water systems. According to the ground water monitoring
requirements, systems are subject to monitor finished water at each
entry point to the distribution system for radon during periods of
ground water use. For the purpose of determining compliance, systems
supplementing their surface water during part of the year will use a
value of \1/2\ the detection limit for radon for averaging purposes
for the quarters when the water system is not supplemented by ground
water. The water system having ground water samples supplementing
surface water with a radon detection level above the MCL would not
be out of compliance provided that these samples do not cause the
average to exceed the MCL when averaged with the value of \1/2\ the
detection limit during the quarters the ground water source is not
in use.
Averaging quarterly samples: Commenters recommended clarifying
the discussion concerning the averaging of initial measurements to
determine compliance. They stated that averaging the first year
quarterly samples with the annual second and third compliance years
will defeat the purpose of quarterly samples detecting signs of
seasonal variability.
EPA Response: EPA is retaining the quarterly monitoring
requirement for radon as proposed initially in the 1991 proposal to
account for variations such as sampling, analytical and temporal
variability in radon levels. Results of analysis of data obtained
since 1991, estimating contributions of individual sources of
variability to overall variance in the radon data sets evaluated,
indicated that sampling and analytical variance contributes less
than 1 percent to the overall variance. Temporal variability within
single wells accounts for between 13 and 18 percent of the variance
in the data sets evaluated, and a similar proportion (12-17 percent)
accounts for variation in radon levels among wells within systems
(USEPA 1999c).
For today's proposal, the Agency performed additional analyses
to determine whether the requirement of initial quarterly monitoring
for radon was adequate to account for seasonal variations in radon
levels and to identify non-compliance with the MCL/AMCL. Results of
analysis based on radon levels modeled for radon distribution for
ground water sources and systems (USEPA 1999c) in the U.S. show that
the average of the first four quarterly samples provides a good
indication of the probability that the long-term average radon level
in a given source would exceed an MCL or AMCL. Tables A.1 and A.2
show the probability of the long-term average radon level exceeding
the MCL and AMCL at various averages obtained from the first four
quarterly samples from a source.
Table A.1.--The Relationship Between the First-Year Average Radon Level
and the Probability of the Long-Term Radon Average Radon Levels
Exceeding the MCL
------------------------------------------------------------------------
Then the probability that the
If the average of the first four long-term average radon level
quarterly samples from a source is: in that source exceeds 300
pCi/L is:
------------------------------------------------------------------------
Less than 50 pCi/L....................... 0 percent
Between 50 and 100 pCi/L................. 0.5 percent
Between 100 and 150 pCi/L................ 0.4 percent
Between 150 and 200 pCi/L................ 7.2 percent
Between 200 and 300 pCi/L................ 26.8 percent
------------------------------------------------------------------------
Table A.2.--The Relationship Between the First-Year Average Radon Level
and the Probability of the Long-Term Radon Average Radon Levels
Exceeding the AMCL
------------------------------------------------------------------------
Then the probability that the
If the average of the first four long-term average radon level
quarterly samples from a source is: in that source exceeds 4000
pCi/L is:
------------------------------------------------------------------------
Less than 2,000 pCi/L.................... Less than 0.1 percent
Between 2,000 and 2,500 pCi/L..... 9.9 percent
Between 2,500 and 3,000 pCi/L..... 15.1 percent
Between 3,000 and 4,000 pCi/L..... 32.9 percent
------------------------------------------------------------------------
[[Page 59369]]
Water systems with a history of compliance: EPA has provided for
the grandfathering of prior monitoring data for granting waivers.
Monitoring data collected after January 1, 1985, that are generally
consistent with the requirements of the section, and includes at
least one sample taken on or after January 1, 1993, may be accepted
by the State to satisfy the initial monitoring requirements. Many
systems meeting the current monitoring requirements should qualify
for this grandfathering provision because each sampling point or
source water intake will be monitored within the preceding four-year
period. New sampling points, or sampling points with new sources,
must take an initial sample within the year the new source or
sampling point begins operation.
EPA Response: Today's proposal provides that at a State's
discretion, sampling data collected after the proposal could be used
to satisfy the initial sampling requirements for radon, provided
that the system has conducted a monitoring program not less
stringent than that specified in the regulation and used analytical
methods specified in the proposed regulation. The Agency wants to
provide water suppliers with the opportunity to synchronize their
monitoring program with other contaminants and to get an early start
on their monitoring program if they wish to do so.
The proposed regulation provides for the States to grant
monitoring waiver reducing monitoring frequency to once every nine
years (once per compliance cycle) provided the system demonstrates
that it is unlikely that radon levels in drinking water will occur
above the MCL/AMCL. In granting the waiver, the State must take into
consideration factors such as the geological area where the water
source is located, and previous analytical results which demonstrate
that radon levels do not occur above the MCL/AMCL. The waiver will
be granted for up to a nine year period. (Given that all previous
samples are less than \1/2\ the MCL/AMCL, then it is highly unlikely
that the long-term average radon levels would exceed the MCL/AMCL.)
References Cited in Appendix 1 to the Preamble
American Water Works Association Research Foundation. Critical
Assessment of Radon Removal Systems for Drinking Water Supplies,
Denver, CO. [December 1998] [AWWARF 1998a]
American Water Works Association Research Foundation. Assessment of
GAC Adsorption for Radon Removal. Final Draft, Denver, CO. [April
1998] [AWWARF 1998b]
Correia, J.A., Weise, S.B., Callahan, R.J., and Strauss, H.W. The
Kinetics of Ingested Rn-222 in Humans Determined from Measurements
with Xe-133. Massachusetts General Hospital, Boston, MA, unpublished
report (As cited in Crawford-Brown 1990). [1987] [Correia, et al.
1987]
Crawford-Brown, D.J. Final Report: Risk and Uncertainty Analysis for
Radon in Drinking Water. American Water Works Association, Denver,
CO. [1992] [Crawford-Brown 1992]
Edling, C. and Axelson, O. Quantitative Aspects of Radon Daughter
Exposure and Lung Cancer in Underground Miners, Br. J. Ind. Med.
(40:182-187) [1983] [Edling and Axelson 1983]
Ershow, A.G. and Cantor, K.P. Total Water and Tapwater Intake in the
United States: Population-based Estimates of Quantities and Sources.
Report prepared under National Cancer Institute Order #263-MD-
810264. [1989] [Ershow and Cantor 1989]
Federal Register, Vol. 64, No. 38. Health Risk Reduction and Cost
Analysis (HRRCA) for Radon in Drinking Water: Notice, Request for
Comments and Announcement of Stakeholder Meeting. (Feb. 26, 1999)
9559-9599. [64 FR 9559]
Field, R.W., Fisher, E.L., Valentine, R.L., and Kross, B.C. Radium-
Bearing Pipe Scale Deposits: Implications for National Waterborne
Radon Sampling Methods. Am.J. Public Health (85:567-570) [April
1995] [Field et al. 1995]
Gesell, T.F. and Prichard, H.M. The Contribution of Radon in Tap
Water to Indoor Radon Concentrations. In: Gesell T.F. and W.M.
Lowder, eds. Natural radiation environment III, Vol. 2. Washington,
DC: U.S. Department of Energy, Technical Information Center, pp.
1347-1363. CONF-780422 (Vol. 2). [1980] [Gesell and Prichard 1980]
Horton, T.R. Results of Drinking Water Experiment. Memorandum from
T.R. Horton of the Environmental Studies Branch to Charles R.
Phillips. [1982] [Horton 1982]
Hursh, J.B., Morken, D.A. Davis, T.P., and Lovaas, A. The Fate of
Radon Ingested by Man. Health Phys. (11:465-476). [1965] [Hursh, et
al. 1965]
Kinner, N.E., Malley, J.P., and Clement, J.A. Radon Removal Using
Point-of-Entry Water Treatment Techniques. EPA/600/2-90/047.
Cincinnati, OH: Risk Reduction Engineering Laboratory. [1990]
[Kinner, et al. 1990]
National Academy of Sciences, National Research Council. Health Risk
of Radon and Other Internally Deposited Alpha-Emitters: (BEIR IV)
National Academy Press, Washington, DC. [1988] [NAS 1988]
National Academy of Sciences, National Research Council. Health
Effects of Exposure to Low Levels of Ionizing Radiation (BEIR V).
National Academy Press, Washington, DC. [NAS 1990]
National Academy of Sciences, National Research Council. Comparative
Dosimetry of Radon in Mines and Homes. National Academy Press,
Washington, DC. [NAS 1991]
National Academy of Sciences, National Research Council. Health
Effects of Exposure to Radon. (BEIR VI.) National Academy Press,
Washington, DC. [NAS 1999a]
National Academy of Sciences, National Research Council, Committee
on the Risk Assessment of Exposure to Radon in Drinking Water, Board
on Radiation Effects Research. Risk Assessment of Radon in Drinking
Water. National Academy Press, Washington, DC. [NAS 1999b]
National Institute of Occupational Safety and Health. Criteria for a
Recommended Standard: Occupation Exposure to Radon Progeny in
Underground Mines. U.S. Government Printing Office. [1987] [NIOSH
1987]
Pennington, J.A. Revision of the Total Diet Study Food List and
Diets. J. Am. Diet. Assoc. (82:166-173) [1983] [Pennington 1983]
Radford, E.P. and St. Clair Renard, K.G. Lung Cancer in Swedish Iron
Miners Exposed to Low Doses of Radon Daughters. N. Engl. J. Med.
(310(23):1485-1494) [1984] [Radford and St. Clair Renard 1984]
Sevc J., Kunz, E., Placek, V., and Smid, A. Comments on Lung Cancer
Risk Estimates. Health Phys. (46: 961-964) [1984] [Sevc, et al.
1984]
Sevc, J., Kunz, E., Tomasek, L., Placek, V., and Horacek, J. Cancer
in Man after Exposure to Rn Daughters. Health Phys. (54:27-46)
[1988] [Svec, et al. 1988]
Suomela M. and Kahlos, H. Studies on the Elimination Rate and the
Radiation Exposure Following Ingestion of 222-Rn Rich Water. Health
Phys. (23:641-652) [1972] [Suomela and Kahlos 1972]
United Nations Scientific Committee on the Effects of Atomic
Radiation. Sources, Effects and Risks of Ionizing Radiation. United
Nations, NY. [1988] [UNSCEAR 1988]
U.S. Environmental Protection Agency, Office of Radiation Programs.
An Estimation of the Daily Average Food Intake by Age and Sex for
Use in Assessing the Radionuclide Intake of Individuals in the
General Population. EPA 520/1-84-021. [1984] [USEPA 1984]
U.S. Environmental Protection Agency. Examination of Kennedy/Jenks
Cost Estimates for Radon Removal by Packed Column Air Stripping.
Memorandum to Marc Parrotta, ODW, from Michael Cummins, ODW.
[November 23, 1992] [USEPA 1992]
U.S. Environmental Protection Agency, Office of Science and
Technology, Office of Radiation and Indoor Air, Office of Policy,
Planning, and Evaluation. Uncertainty Analysis of Risks Associated
with Exposure to Radon in Drinking Water. TR-1656-3B. [April 30,
1993] [USEPA 1993]
U.S. Environmental Protection Agency, Office of Water. Report to
United States Congress on Radon in Drinking Water: Multimedia Risk
Assessment of Radon. EPA-811-R-94-001. [March 1994] [USEPA 1994]
U.S. Environmental Protection Agency, Office of Science and
Technology, Office of Radiation and Indoor Air, Office of Policy,
Planning and Evaluation. Uncertainty Analysis of Risks Associated
with Exposure to Radon in Drinking Water. EPA 822-R-96-005. [March,
1995] [USEPA 1995]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Community Water System Survey. Volume II: Detailed
Survey Result Tables and Methodology Report. EPA 815-R-97-0016.
[January 1997] [USEPA 1997]
U.S. Environmental Protection Agency, Office of Radiation and Indoor
Air. Health Risks from Low-Level Environmental Exposure to
Radionuclides. Federal
[[Page 59370]]
Guidance Report No. 13. Part I--Interim Version. EPA 401/R-97-014.
[1998] [USEPA 1998]
U.S. Environmental Protection Agency. Technologies and Costs for the
Removal of Radon from Drinking Water. Prepared by Science
Applications International Corporation for EPA. [May 1999] [USEPA
1999a]
U.S. Environmental Protection Agency. EPA's Unit Capital Cost
Estimates for Aeration for Radon Treatment Versus AWWA and ACWA's
Estimates from 1992 (Kennedy/Jenks Report) and AWWARF 1995.
Memorandum to Sylvia Malm, OGWDW, from William Labiosa, OGWDW. [July
28, 1999] [USEPA 1999b]
U.S. Environmental Protection Agency, Office of Ground Water and
Drinking Water. Methods, Occurrence and Monitoring Document for
Radon. Draft. [August 3, 1999] [USEPA 1999c]
U.S. Environmental Protection Agency, Office of Science and
Technology. Draft Criteria Document for Radon in Drinking Water.
[June 1999] [USEPA 1999d]
Valentine, R., Stearns, S., Kurt, A., Walsh, D., and Mielke, W.
Radon and Radium from Distribution System and Filter Media Deposits.
Presented at AWWA Water Quality Technology Conference, Toronto.
[November, 1992] [Valentine et al. 1992]
von Dobeln, W. and Lindell, B. Some Aspects of Radon Contamination
Following Ingestion. Arkiv for Fysik. 27:531-572 [1964] [von Dobeln
and Lindell 1964]
List of Subjects
40 CFR Part 141
Environmental protection, Chemicals, Indians--lands,
Intergovernmental relations, Radiation protection, Reporting and
recordkeeping requirements, Water supply.
40 CFR Part 142
Environmental protection, Administrative practice and procedure,
Chemicals, Indians--lands, Radiation protection, Reporting and
recordkeeping requirements, Water supply.
Dated: October 19, 1999.
Carol M. Browner,
Administrator.
For the reasons set out in the preamble, the Environmental
Protection Agency proposes to amend 40 CFR parts 141 and 142 as
follows:
PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS
1. The authority citation for part 141 continues to read as
follows:
Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9, and 300j-11.
2. Section 141.2 is amended by adding definitions of ``Alternative
Maximum Contaminant Level (AMCL)'' and ``Multimedia Mitigation (MMM)
Program Plan'' in alphabetical order, to read as follows:
Sec. 141.2 Definitions.
* * * * *
Alternative Maximum Contaminant Level (AMCL) is the permissible
level of radon in drinking water delivered by a community water system
in a State with an EPA-approved multimedia mitigation (MMM) program
plan, or by a community water system with a State-approved local MMM
program plan.
* * * * *
Multimedia Mitigation (MMM) Program Plan is a State or community
water system program plan of goals and strategies developed with public
participation to promote indoor radon risk reduction. MMM programs for
radon in indoor air may use a variety of strategies, including public
education, testing, training, technical assistance, remediation grant
and loan or incentive programs, or other regulatory or non-regulatory
measures.
* * * * *
3. Section 141.6 is amended by adding paragraph (j) to read as
follows:
141.6 Effective dates.
* * * * *
(j) The regulations set forth in Subpart R of this part are
effective [60 days after date of publication of the final rule in the
Federal Register].
Subpart C--[Amended]
4. A new Sec. 141.20 is added to Subpart C to read as follows:
Sec. 141.20 Analytical methods, monitoring, and compliance
requirements for radon.
(a) Analytical methods. (1) Analysis for radon shall be conducted
using one of the methods in the following table:
Proposed Analytical Methods for Radon in Drinking Water
----------------------------------------------------------------------------------------------------------------
References (method or page number)
Methodology ---------------------------------------------------------------------------
SM ASTM EPA
----------------------------------------------------------------------------------------------------------------
Liquid Scintillation Counting....... 7500-Rn\1\.............. D 5072 92\2\........... .......................
De-emanation........................ ........................ ....................... EPA 1987\3\
----------------------------------------------------------------------------------------------------------------
\1\ Standard Methods for the Examination of Water and Wastewater. 19th Edition Supplement. Clesceri, L., A.
Eaton, A. Greenberg, and M. Franson, eds. American Public Health Association, American Water Works
Association, and Water Environment Federation. Washington, DC. 1996.
\2\ American Society for Testing and Materials (ASTM). Standard Test Method for Radon in Drinking Water.
Designation: D 5072-92. Annual Book of ASTM Standards. Vol. 11.02. 1996.
\3\ Appendix D, Analytical Test Procedure, ``The Determination of Radon in Drinking Water''. In ``Two Test
Procedures for Radon in Drinking Water, Interlaboratory Collaborative Study''. EPA/600/2-87/082. March 1987.
p. 22.
(2) Sample collection for radon shall be conducted using the sample
preservation, container, and maximum holding time procedures specified
in the following table.
Sampling Methods and Sample Handling, Preservation, and Holding Time
----------------------------------------------------------------------------------------------------------------
Maximum holding time
Sampling methods Preservative Sample Container for sample
----------------------------------------------------------------------------------------------------------------
(i) As described in SM 7500-Rn\1\... Ship sample in an Glass with teflon-lined 4 days.
insulated package to septum.
avoid large temperature
changes.
[[Page 59371]]
(ii) As described in EPA 1987\2\ ...
----------------------------------------------------------------------------------------------------------------
\1\ Standard Methods for the Examination of Water and Wastewater. 19th Edition Supplement. Clesceri, L., A.
Eaton, A. Greenberg, and M. Franson, eds. American Public Health Association, American Water Works
Association, and Water Environment Federation. Washington, DC. 1996.
\2\ ``Two Test Procedures for Radon in Drinking Water, Interlaboratory Collaborative Study''. EPA/600/2-87/082.
March 1987.
(b) Monitoring and compliance requirements. Community water systems
(CWSs) shall conduct monitoring to determine compliance with the
maximum contaminant level (MCL) or alternate maximum contaminant level
(AMCL) specified in Sec. 141.66 in accordance with this chapter. The
monitoring requirements have been developed to be consistent with the
Phase II/V monitoring schedule.
(1) Applicability and sampling location. CWSs using a ground water
source or CWSs using ground water and surface water sources (for the
purpose of this section hereafter referred to as systems) shall sample
at every entry point to the distribution system which is representative
of each well after treatment and/or storage (hereafter called a
sampling point) under normal operating conditions in accordance with
paragraph (b)(2) of this section.
(2) Monitoring--(i) Initial monitoring requirements. (A) Systems
must collect four consecutive quarterly samples beginning by the date
specified in Sec. 141.301(b).
(B) States may allow previous sampling data collected after [60
days after date of publication of the final rule] to satisfy the
initial monitoring requirements, provided the system has conducted
monitoring to satisfy the requirements specified in this section. If a
system's early monitoring data indicates an MCL/AMCL exceedence, the
system will not be considered in violation until the end of the
applicable initial monitoring period specified in Sec. 141.301(b).
(ii) Routine monitoring requirements. Systems must continue
quarterly monitoring until the running average of four consecutive
quarterly samples is less than the MCL/AMCL. If the running average of
four consecutive quarterly samples is less than the MCL/AMCL then
systems may conduct annual monitoring at the State's discretion.
(iii) Reduced monitoring requirements. States may allow systems to
reduce the frequency of monitoring to once every three years (one
sample per compliance period) beginning the following compliance period
provided the systems:
(A) Demonstrate that the average of four consecutive quarterly
samples is below \1/2\ MCL/AMCL;
(B) No individual samples exceed the MCL/AMCL; and
(C) The States determine that the systems are reliably and
consistently below the MCL/AMCL.
(iv) Increased monitoring requirements. (A) Systems which exceed
the MCL/AMCL shall monitor quarterly beginning the quarter following
the exceedence. States may allow systems to reduce their monitoring
frequency if the requirements specified in paragraph (b)(2)(iii) or
(b)(2)(iv)(B) of this section are met.
(B) Systems monitoring once every three years, or less frequently,
which exceed \1/2\ MCL/AMCL shall begin annual monitoring the year
following the exceedence. Systems may reduce monitoring to once every
three years if the average of the initial and three consecutive annual
samples is less than \1/2\ MCL/AMCL and the State determines the system
is reliably and consistently below the MCL/AMCL.
(C) If a community water system has a portion of its distribution
system separable from other parts of the distribution system with no
interconnections, increased monitoring need only be conducted at points
of entry to those portions of system.
(v) Failure to conduct monitoring as described in this section is a
monitoring violation.
(3) Monitoring waivers. (i) States may grant a monitoring waiver to
systems provided that:
(A) The system has completed initial monitoring requirements as
specified in paragraph (b)(2)(i) of this section. Systems shall
demonstrate that all previous analytical results were less than \1/2\
MCL/AMCL. New systems and systems using a new ground water source must
complete four consecutive quarters of monitoring before the system is
eligible for a monitoring waiver; and
(B) States determine that the systems are reliably and consistently
below the MCL/AMCL, based on a consideration of potential radon
contamination of the source water due to the geological characteristics
of the source water aquifer.
(ii) Systems with a monitoring waiver must collect a minimum of 1
sample every nine-years (once per compliance cycle).
(iii) A monitoring waiver remains in effect until completion of the
nine-year compliance cycle.
(iv) A decision by States to grant a monitoring waiver shall be
made in writing and shall set forth the basis for the determination.
(4) Confirmation samples. Systems may take additional samples to
verify initial sample results as specified by the State. The results of
the initial and confirmation samples will be averaged for use in
calculation of compliance.
(5) Compliance. Compliance with Sec. 141.66 shall be determined
based on the analytical result(s) obtained at each sampling point. If
one sampling point is in violation, the system is in violation.
(i) For systems monitoring more frequently than annually,
compliance with the MCL/AMCL is determined by a running annual average
at each sampling point. If the average at any sampling point is greater
than the MCL/AMCL, then the system is out of compliance with the MCL/
AMCL.
(ii) If any one quarterly sampling result will cause the running
average to exceed the MCL/AMCL, the system is out of compliance.
(iii) Systems monitoring annually or less frequently whose sample
result exceeds the MCL/AMCL will revert to quarterly sampling
immediately. The system will not be considered in violation of the MCL/
AMCL until they have completed one year of quarterly sampling.
(iv) All samples taken and analyzed under the provisions of this
section must be included in determining compliance, even if that number
is greater than the minimum required.
(v) If a system does not collect all required samples when
compliance is based on a running annual average of
[[Page 59372]]
quarterly samples, compliance will be based on available data.
(vi) If a sample result is less than the detection limit, zero will
be used to calculate the annual average.
(vii) During the initial monitoring period, if the compliance
determination for a system in a non-MMM State exceeds the MCL, the
system will incur a MCL violation unless the system notifies the State
by [four years after date of publication of the final rule in the
Federal Register] of their intent to submit a local MMM plan, submits a
local MMM plan to the State within [5 years after date of publication
of the final rule in the Federal Register] and begins implementation by
[5.5 years after date of publication of the final rule in the Federal
Register]. The State shall approve or disapprove a local MMM program
plan within 6 months from the date of receipt. If the State does not
disapprove the local MMM program plan during such period, then the CWS
shall implement the plan submitted to the State for approval. The
compliance determination will be conducted as described in this
paragraph.
(viii) Following the completion of the initial monitoring period,
if the compliance determination for a system in a non-MMM State exceeds
the MCL, the system will incur a MCL violation unless the system
submits a local MMM plan to the State within 1 year from the date of
the exceedence and begins implementation 1.5 years from the date of the
exceedence. The State shall approve or disapprove a local MMM program
plan within 6 months from the date of receipt. If the State does not
disapprove the local MMM program plan during such period, then the CWS
shall implement the plan submitted to the State for approval. The
compliance determination will be conducted as described in this
paragraph.
(6) If a community water system has a distribution system separable
from other parts of the distribution system with no interconnections,
the State may allow the system to give public notice to only the area
served by that portion of the system which is out of compliance.
5. Section 141.28 is revised to read as follows:
Sec. 141.28 Certified laboratories.
(a) For the purpose of determining compliance with Sec. 141.20
through 141.27, 141.41, and 141.42, samples may be considered only if
they have been analyzed by a laboratory certified by the State except
that measurements for turbidity, free chlorine residual, temperature
and pH may be performed by any person acceptable to the State.
(b) Nothing in this part shall be construed to preclude the State
or any duly designated representative of the State from taking samples
or from using the results from such samples to determine compliance by
a supplier of water with the applicable requirements of this part.
Subpart F--[Amended]
6. A new Sec. 141.55 is added to Subpart F to read as follows:
Sec. 141.55 Maximum contaminant level goals for radionuclides.
MCLGs are as indicated in the following table:
------------------------------------------------------------------------
Contaminant MCLG
------------------------------------------------------------------------
Radon-222.................................... Zero.
------------------------------------------------------------------------
Subpart G--[Amended]
7. A new Sec. 141.66 is added to Subpart G to read as follows:
Sec. 141.66 Maximum contaminant level for radionuclides.
(a) The maximum contaminant level for radon-222 is as follows: (1)
A community water system (CWS) using a ground water source or using
ground water and surface water sources that serves 10,000 or fewer
people shall comply with the alternative maximum contaminant level
(AMCL) of 4000 pCi/L, and implement a State-approved multimedia
mitigation (MMM) program to address radon in indoor air (unless the
State in which the system is located has a MMM approved by the
Environmental Protection Agency). These systems may elect to comply
with the MCL of 300 pCi/L instead of developing a local CWS MMM program
plan.
(2) A CWS using a ground water source or using ground water and
surface water sources that serves more than 10,000 people shall comply
with the MCL of 300 pCi/L, except that the system may comply with an
AMCL of 4000 pCi/L where:
(i) The State in which the CWS is located has adopted an MMM
program plan approved by EPA; or,
(ii) The CWS has adopted an MMM program plan approved by the State.
(3) A CWS shall monitor for radon in drinking water according to
the requirements in Sec. 141.20, and report the results to the State,
and continue to monitor as described in Sec. 141.20. If the State
determines that the CWS is in compliance with the MCL of 300 pCi/L, the
CWS has met the requirements of this section and is not subject to the
requirements of subpart R of this part, regarding MMM programs.
(4) The Administrator, pursuant to section 1412 of the Act, hereby
identifies, as indicated in the following table, the best technology
available for achieving compliance with the maximum contaminant levels
for radon identified in paragraphs (a)(1) and (a)(2) of this section:
BAT for Radon-222
High-Performance Aeration \1\
(5) The Administrator, pursuant to section 1412 of the Act, hereby
identifies in the following table the best technology available to
systems serving 10,000 persons or fewer for achieving compliance with
the MCL or AMCL. The table addresses affordability and technical
feasibility for such BAT.
---------------------------------------------------------------------------
\1\ High Performance Aeration is defined as the group of
aeration technologies that are capable of being designed for high
radon removal efficiencies, i.e., Packed Tower Aeration, Multi-Stage
Bubble Aeration and other suitable diffused bubble aeration
technologies, Shallow Tray and other suitable Tray Aeration
technologies, and any other aeration technologies that are capable
of similar high performance.
Proposed Small Systems Compliance Technologies (SSCTS) \1\ and Associated Contaminant Removal Efficiencies
----------------------------------------------------------------------------------------------------------------
Affordable for
Small systems compliance listed small Removal Operator level Limitations (see
technology systems efficiency required \3\ footnotes)
categories \2\
----------------------------------------------------------------------------------------------------------------
Packed Tower Aeration (PTA)... All Size 90->99.9% Removal Intermediate.......... (a)
Categories.
High Performance Package Plant All Size 90-> 99.9% Basic to Intermediate. (a)
Aeration (e.g., Multi-Stage Categories. Removal.
Bubble Aeration, Shallow Tray
Aeration).
Diffused Bubble Aeration...... All Size 70 to >99% Basic................. (a, b)
Categories. removal.
[[Page 59373]]
Tray Aeration................. All Size 80 to >90%....... Basic................. (a, c)
Categories.
Spray Aeration................ All Size 80 to >90%....... Basic................. (a, d)
Categories.
Mechanical Surface Aeration... All Size >90%............. Basic................. (a, e)
Categories.
Centralized granular activated May not be 50 to >99% Basic................. (f)
carbon. affordable, Removal.
except for very
small flows.
Point-of-Entry (POE) granular May be affordable 50 to >99% Basic................. (f, g)
activated carbon. for systems Removal.
serving fewer
than 500 persons.
----------------------------------------------------------------------------------------------------------------
\1\ Section 1412(b)(4)(E)(ii) of the SDWA specifies that SSCTs must be affordable and technically feasible for
small systems.
\2\ The Act (ibid.) specifies three categories of small systems: i) those serving 25 or more, but fewer than
501, ii) those serving more than 500, but fewer than 3,301, and iii) those serving more than 3,300, but fewer
than 10,001.
\3\ From National Research Council. Safe Water from Every Tap: Improving Water Service to Small Communities.
National Academy Press. Washington, DC. 1997. Limitations: a) Pre-treatment to inhibit fouling may be needed.
Post-treatment disinfection and/or corrosion control may be needed. b) May not be as efficient as other
aeration technologies because it does not provide for convective movement of the water, which reduces the
air:water contact. It is generally used in adaptation to existing basins. c) Costs may increase if a forced
draft is used. Slime and algae growth can be a problem, but may be controlled with chemicals, e.g., copper
sulfate or chlorine. d) In single pass mode, may be limited to uses where low removals are required. In
multiple pass mode (or with multiple compartments), higher removals may be achieved. e) May be most applicable
for low removals, since long detention times, high energy consumption, and large basins may be required for
larger removal efficiencies. f) Applicability may be restricted to radon influent levels below around 5000 pCi/
L to reduce risk of the build-up of radioactive radon progeny. Carbon bed disposal frequency should be
designed to allow for standard disposal practices. If disposal frequency is too long, radon progeny, radium,
and/or uranium build-up may make disposal costs prohibitive. Proper shielding may be required to reduce gamma
emissions from the GAC unit. GAC may be cost-prohibitive except for very small flows. g) When POE devices are
used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be
provided by the water system to ensure adequate performance.
Subpart O--[Amended]
8. Section 141.151 is amended by revising paragraph (d) to read as
follows:
141.151 Purpose and applicability of this subpart.
* * * * *
(d) For the purpose of this subpart, detected means: at or above
the levels prescribed by Sec. 141.23(a)(4) for inorganic contaminants,
at or above the levels prescribed by Sec. 141.24(f)(7) for the
contaminants listed in Sec. 141.61(a), at or above the level prescribed
by Sec. 141.24(h)(18) for the contaminants listed in Sec. 141.61(c), at
or above the level prescribed by Sec. 141.66 for radon, and at or above
the levels prescribed by Sec. 141.25(c) for radioactive contaminants.
* * * * *
9. Section 141.153 is amended by revising paragraph (d)(1)(i);
removing paragraph (e)(2) and redesignating paragraph (e)(3) as (e)(2);
redesignating paragraphs (f)(5), (f)(6), and (f)(7) as (f)(6), (f)(7),
and (f)(8); and adding paragraph (f)(5) to read as follows:
Sec. 141.153 Content of the reports.
* * * * *
(d) * * *
(1) * * *
(i) Contaminants subject to a MCL, AMCL, action level, or treatment
technique (regulated contaminants);
* * * * *
(f) * * *
(5) Local multimedia radon mitigation programs prescribed by
subpart R of this part.
* * * * *
10. Section 141.154 is amended by adding paragraph (f) as follows:
Sec. 141.154 Required additional health information.
* * * * *
(f) In each complete calendar year between [date of publication of
final rule in the Federal Register] and [4 years after date of
publication of the final rule in the Federal Register], each report
from a system that has ground water as a source must include the
following notice (except that a system developing a local MMM program
in a non-MMM State needs to include this statement in each calendar
year between [date of publication of the final rule in the Federal
Register] and [5 years after date of publication of the final rule in
the Federal Register] :
Radon is a naturally-occurring radioactive gas found in soil and
outdoor air that may also be found in drinking water and indoor air.
Some people exposed to elevated radon levels over many years in
drinking water may have an increased risk of getting cancer. The
main health risk is lung cancer from radon entering indoor air from
soil under homes. Your water system plans to test for radon by
[insert date], and if radon is detected your water system will
provide the results of testing to their customers. The best way to
reduce the overall risk from radon is to reduce radon levels in
indoor air. Some States, and water systems, may now be working to
develop a program to reduce radon exposure in indoor air and
drinking water. To get more information and to help develop the
program, call the Radon Hotline (800-SOS-RADON) or visit the web
site http://www.epa.gov/iaq/radon/.
Subpart Q--[Amended]
11. In Sec. 141.201, Table 1 proposed on May 13, 1999, at 64 FR
25964 is amended by revising paragraphs (1) introductory text and
(1)(i) to read as follows:
Sec. 141.201 General Public Notification Requirements.
* * * * *
Table 1 to Sec. 141.201--Violation Categories and Other Situations
Requiring a Public Notice.
(1) NPDWR violations (MCL/AMCL, local MMM, MRDL, treatment
technique, monitoring and testing procedure)
(i) Failure to comply with an applicable maximum contaminant level
(MCL), alternative maximum contaminant level (AMCL), the local
multimedia mitigation requirement for small systems in non-MMM States,
or maximum residual disinfectant level (MRDL).
* * * * *
12. In Sec. 141.203, Table 1 proposed on May 13, 1999, at 64 FR
25964 is amended by revising paragraph (1) to read as follows:
Sec. 141.203 Tier 2 Public Notice--Form, manner, and frequency of
notice.
* * * * *
[[Page 59374]]
Table 1 to Sec. 141.203. Violation Categories and Other Situations
Requiring a Tier 2 Public Notice
(1) All violations of the MCL, AMCL, MRDL, and treatment technique
requirements not included in the Tier 1 notice category;
* * * * *
13. In Sec. 141.204, Table 1 proposed on May 13, 1999, at 64 FR
25964 is amended by adding paragraph (5) to read as follows:
Sec. 141.204. Tier 3 Public Notice--Form, manner, and frequency of
notice.
* * * * *
Table 1 to Sec. 141.204. Violation Categories and Other Situations
Requiring a Tier 3 Public Notice
(5) All violations of the MMM requirements not included in the Tier
1 or 2 notice category;
* * * * *
14. Section 141.205 proposed on May 13, 1999, at 64 FR 25964 is
amended by revising paragraph (d)(1), to read as follows:
Sec. 141.205 Content of the public notice.
* * * * *
(d) * * *
(1) Standard health effects language for MCL, AMCL, MMM or MRDL
violations, treatment technique violations, and violations of the
condition of a variance or exemption. Public water systems must include
in each public notice the health effects language specified in Appendix
B to this subpart corresponding to each MCL, AMCL, MMM, MRDL, and
treatment technique violation listed in Appendix A to this subpart, and
for each violation of a condition of a variance or exemption.
* * * * *
15. Part 141 is amended by adding a new Subpart R to read as
follows:
Subpart R--Reducing Radon Risks In Indoor Air and Drinking Water
Sec.
141.300 Applicability.
141.301 General requirements.
141.302 Multimedia mitigation (MMM) requirements (required elements
of MMM program plans).
141.303 Multimedia mitigation (MMM) reporting and compliance
requirements.
141.304 Local multimedia mitigation program plan approval and
program review.
141.305 States that do not have primacy.
Subpart R--Reducing Radon Risks in Indoor Air and Drinking Water
Sec. 141.300 Applicability.
(a) The requirements of this subpart constitute national primary
drinking water regulations for radon. The provisions of this subpart
apply to community water systems (CWS) using a ground water source or
using ground water and surface water sources. CWSs must monitor for
radon in drinking water according to the requirements described in
Sec. 141.20, and report the results to the State, and continue to
monitor as described in Sec. 141.20. If the State determines that the
CWS is in compliance with the MCL of 300 pCi/L, the CWS has met the
requirements of this section and is not subject to the requirements of
this subpart.
(b) These regulations in this subpart establish criteria for the
development and implementation of program plans to mitigate radon in
indoor air and drinking water (multimedia mitigation or MMM program
plan). In general, where a State, CWS, or Tribal MMM program plan is
approved, CWSs comply with an AMCL of 4000 pCi/L (Sec. 141.66). In
jurisdictions without an approved MMM program plan, large CWSs (serving
greater than 10,000 people) must comply with an MCL of 300 pCi/L
(Sec. 141.66), except they comply with the AMCL of 4000 pCi/L if they
develop a CWS MMM program plan approved by the State. Small community
water systems serving 10,000 or fewer people must comply with 4000 pCi/
L and implement a State-approved multimedia mitigation program plan to
address radon in indoor air (unless the State in which the system is
located has a multimedia mitigation program plan approved by the
Environmental Protection Agency); these systems have the option of
complying with the MCL instead of implementing a MMM program.
Sec. 141.301 General requirements.
(a) The requirements for the MMM program plan are set out in this
subpart. The requirements for the MCL are set out in Sec. 141.20(a)
(analytical methods), Sec. 141.20(b) (monitoring and compliance),
Sec. 141.66(a) through (c) (requirements for systems, including MCL and
AMCL), and Sec. 141.66(d) (BAT).
(b) Compliance dates.--(1) Initial monitoring. (i) For States that
submit a letter to the Administrator by [90 days after date of
publication of the final rule in the Federal Register] committing to
develop an MMM program plan in accordance with section
1412(b)(13)(G)(v) of the Act, CWSs must begin one year of quarterly
monitoring for compliance with the AMCL by [4.5 years after date of
publication of the final rule in the Federal Register].
(ii) For States not submitting a letter to the Administrator by [90
days after date of publication of final rule in the Federal Register]
committing to develop an MMM program plan, CWSs must begin one year of
quarterly monitoring for compliance with the MCL/AMCL by [3 years after
date of publication of final rule in the Federal Register].
(2) State-wide MMM programs. (i) For States that submit a letter to
the Administrator by [90 days after date of publication of the final
rule in the Federal Register] committing to develop an MMM program plan
in accordance with section 1412(b)(13)(G)(v), implementation of the
State-wide MMM program must begin by [4.5 years after date of
publication of the final rule in the Federal Register].
(ii) For States not submitting a letter to the Administrator by [90
days after date of publication of the final rule in the Federal
Register] committing to develop an MMM program plan, but which
subsequently decide to adopt the AMCL, implementation of the State-wide
MMM program must begin by [3 years after date of publication of the
final rule in the Federal Register].
(iii) If EPA-approval of a State MMM program plan is revoked, all
systems have one year from notification by the State to comply with the
MCL. If a system chooses to continue complying with the AMCL and
develop and implement a local MMM program, the State will specify a
timeframe for compliance.
(3) Local MMM programs. (i) During the initial monitoring period,
if the compliance determination for a CWS in a non-MMM State exceeds
the MCL, the CWS will incur an MCL violation unless the system notifies
the State by [four years after date of publication of the final rule in
the Federal Register] of their intent to submit a local MMM plan,
submits a local MMM plan to the State within [5 years after date of
publication of the final rule in the Federal Register] and begins
implementation by [5.5 years after date of publication of the final
rule in the Federal Register]. The compliance determination will be
conducted as described in Sec. 141.20(b)(2).
(ii) Following the completion of the initial monitoring period, if
the compliance determination for a CWS in a non-MMM State exceeds the
MCL, the system will incur an MCL violation unless the system submits a
local MMM plan to the State within 1 year from the date of the
exceedence and begins implementation 1.5 years from the date of the
exceedence. The compliance determination will be conducted as described
in this paragraph.
(iii) The State shall approve or disapprove a local MMM program
plan
[[Page 59375]]
within 6 months from the date of receipt. If the State does not
disapprove the local MMM program plan during such period, the CWS shall
implement the plan submitted to the State for approval.
(iv) If the State determines the CWS is not adequately implementing
the local MMM plan approved by the State, the system shall incur an MMM
violation.
(v) During the MMM program 5-year review periods, the system shall
incur an MMM violation if the State determines the CWS is not meeting
MMM program plan objectives.
Sec. 141.302 Multimedia mitigation (MMM) requirements (required
elements of MMM program plans).
The following are required for approval of State MMM program plans
by EPA. Local MMM program plans developed by community water systems
(CWS) are deemed to be approved by EPA if they meet these criteria (as
appropriate for the local level) and are approved by the State. The
term ``State'', as referenced next, means any entity submitting an MMM
program plan for approval, including States, with and without primacy,
Indian Tribes and community water systems.
(a) Description of process for involving the public. (1) States are
required to involve community water system customers, and other sectors
of the public with an interest in radon, both in drinking water and in
indoor air, in developing their MMM program plan. The MMM program plan
must include:
(i) A description of processes the State used to provide for public
participation in the development of its MMM program plan, including the
components identified in paragraphs (b), (c), and (d) of this section;
(ii) A description of the nature and extent of public participation
that occurred, including a list of groups and organizations that
participated;
(iii) A summary describing the recommendations, issues, and
concerns arising from the public participation process and how these
were considered in developing the State's MMM program plan; and
(iv) A description of how the State made information available to
the public to support informed public participation, including
information on the State's existing indoor radon program activities and
radon risk reductions achieved, and on options considered for the MMM
program plan along with any analyses supporting the development of such
options.
(2) Once the draft program plan has been developed, the State must
provide notice and opportunity for public comment on the draft plan
prior to submitting it to EPA.
(b) Quantitative goals. (1) States are required to establish and
include in their plans quantitative goals, to measure the effectiveness
of their MMM program, for the following:
(i) Existing houses with elevated indoor radon levels that will be
mitigated by the public; and
(ii) New houses that will be built radon-resistant by home
builders.
(2) These goals must be defined quantitatively either as absolute
numbers or as rates. If goals are defined as rates, a detailed
explanation of the basis for determining the rates must be included.
(3) States are required to establish goals for promoting public
awareness of radon health risks, for testing of existing homes by the
public, for testing and mitigation of existing schools, and for
construction of new public schools to be radon-resistant, or to include
an explanation of why goals were not established in these program
areas.
(c) Implementation Plans. (1) States are required to include in
their MMM program plan implementation plans outlining the strategic
approaches and specific activities the State will undertake to achieve
the quantitative goals identified in paragraph (b) of this section.
This must include implementation plans in the following two key areas:
(i) Promoting increased testing and mitigation of existing housing
by the public through public outreach and education and during
residential real estate transactions.
(ii) Promoting increased use of radon-resistant techniques in the
construction of new homes.
(2) If a State has included goals for promoting public awareness of
radon health risks; promoting testing of existing homes by the public;
promoting testing and mitigation of existing schools; and promoting
construction of new public schools to be radon resistant, then the
State is required to submit a description of the strategic approach
that will be used to achieve the goals.
(3) States are required to provide the overall rationale and
support for why their proposed quantitative goals identified in
paragraph (b) of this section, in conjunction with their program
implementation plans, will satisfy the statutory requirement that an
MMM program be expected to achieve equal or greater risk reduction
benefits to what would have been expected if all community water
systems in the State complied with the MCL.
(d) Plans for measuring and reporting results. (1) States are
required to include in the MMM plan submitted to EPA a description of
the approach that will be used to assess the results from
implementation of the State MMM program, and to assess progress towards
the quantitative goals in paragraph (b) of this section. This
specifically includes a description of the methodologies the State will
use to determine or track the number or rate of existing homes with
elevated levels of radon in indoor air that are mitigated and the
number or the rate of new homes built radon-resistant. This must also
include a description of the approaches, methods, or processes the
State will use to make the results of these assessments available to
the public.
(2) If a State includes goals for promoting public awareness of
radon health risks; testing of existing homes by the public; testing
and mitigation of existing schools; and construction of new public
schools to be radon-resistant; the State is required to submit a
description of how the State will determine or track progress in
achieving each of these goals. This must also include a description of
the approaches, methods, or processes the State will use to make these
results of these assessments available to the public.
Sec. 141.303 Multimedia mitigation (MMM) reporting and compliance
requirements.
(a) In accordance with the Safe Drinking Water Act (SDWA), EPA is
to review State MMM programs at least every five years. For the
purposes of this review, the States with EPA-approved MMM program plans
shall provide written reports to EPA in the second and fourth years
between initial implementation of the MMM program and the first 5-year
review period, and in the second and fourth years of every subsequent
5-year review period. States that submit a letter to the Administrator
by [90 days after date of publication of the final rule in the Federal
Register] committing to develop an MMM program plan, must submit their
first 2-year report by 6.5 years from publication of the final rule.
For States not submitting the 90-day letter, but choosing subsequently
to submit an MMM program plan and adopt the AMCL, the first 2-year
report must be submitted to EPA by 5 years from publication of the
final rule. EPA will review these programs to determine whether they
continue to be expected to achieve risk reduction of indoor radon using
the information provided in the two biennial reports.
(b)(1) These reports are required to include the following
information:
[[Page 59376]]
(i) A quantitative assessment of progress towards meeting the
required goals described in Sec. 141.302(b), including the number or
rate of existing homes mitigated and the number or rate of new homes
built radon-resistant since implementation of the States' MMM program,
and,
(ii) A description of accomplishments and activities that implement
the required program strategies, described in Sec. 141.302(c), outlined
in the implementation plans and in the two required areas of promoting
increased testing and mitigation of existing homes and promoting
increased use of radon-resistant techniques in construction of new
homes.
(2) If goals were defined as rates, the State must also provide an
estimate of the number of mitigations and radon-resistant new homes
represented by the reported rate increase for the two-year period.
(3) If the MMM program plan includes goals for promoting public
awareness of the health effects of indoor radon, testing of homes by
the public; testing and mitigation of existing schools; and
construction of new public schools to be radon-resistant, the report is
also required to include information on results and accomplishments in
these areas.
(c) If EPA determines that a MMM program is not achieving progress
towards its goals, EPA and the State shall collaborate to develop
modifications and adjustments to the program to be implemented over the
five year period following the review. EPA will prepare a summary of
the outcome of the program evaluation and the proposed modification and
adjustments, if any, to be made by the State.
(d) If EPA determines that a State MMM program is not achieving
progress towards its MMM goals, and the State repeatedly fails to
correct, modify and adjust implementation of their MMM program after
notice by EPA, EPA will withdraw approval of the State's MMM program
plan. CWSs in the State would then be required to comply with the MCL,
or develop a State-approved CWS MMM program plan. The State will be
responsible for notifying CWSs of the Administrator's withdrawal of
approval of the State-wide MMM program plan. EPA will work with the
State to establish a State process for review and approval of CWS MMM
program plans that meet the required criteria, including local public
participation in development and review of the program plan, and a time
frame for submission of program plans by CWSs that choose to continue
complying with the AMCL.
(e) States shall make available to the public each of these two-
year reports identified in paragraph (a) of this section, as well as
the EPA summaries of the five-year reviews of a State's MMM program,
within 90 days of completion of the reports and the review.
(f) In primacy States without a State-wide MMM program, the States
shall provide a report to EPA every five-years on the status and
progress of CWS MMM programs towards meeting their goals. The first of
such reports would be due by [10.5 years after date of publication of
the final rule in Federal Register].
Sec. 141.304 Local multimedia mitigation program plan approval and
program review.
(a) In States without an EPA-approved MMM program plan, any
community water system may elect to develop and implement a local MMM
program plan that meets the criteria in Sec. 141.302 and comply with
the AMCL in lieu of the MCL. Local CWS MMM program plans must be
approved by the State.
(b) CWSs with State-approved MMM program plans shall report to the
State as required by the State. States shall review such local programs
at least every five years to determine if CWSs are implementing their
program plans and making progress towards their goals. If the CWS fails
to meet those requirements, the State shall require the system to
comply with the MCL.
Sec. 141.305 States that do not have primacy.
(a) If a State, as defined in section 1401 of the Act, that does
not have primary enforcement responsibility for the Public Water System
Program under section 1413 of the Act chooses to submit an MMM program
plan to EPA, that program plan must meet the criteria in Sec. 141.301.
EPA will approve such program plans in accordance with the requirements
of Sec. 141.302.
(b) States with EPA-approved MMM program plans shall report to EPA
in accordance with the requirements of Sec. 141.303.
PART 142--NATIONAL PRIMARY DRINKING WATER REGULATIONS
IMPLEMENTATION
1. The authority citation for part 142 continues to read as
follows:
Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9, and 300j-11.
2. Section 142.12 is amended by adding new paragraph (b)(4) to read
as follows:
Sec. 142.12 Revision of State programs.
* * * * *
(b) * * *
(4) To be granted an extension for radon regulatory requirements
included under 40 CFR part 141, subpart R, the State must commit to
adopt the AMCL and MMM program plan, or MCL.
* * * * *
3. Section 142.15 is amended by adding new paragraph (c)(6) to read
as follows:
Sec. 142.15 Reports by States.
* * * * *
(c) * * *
(6) In accordance with the Safe Drinking Water Act (SDWA), EPA is
to review State MMM programs at least every five years. EPA will review
these programs to determine whether they continue to be expected to
achieve risk reduction of indoor radon using the information provided
in the two biennial reports. For the purposes of this review:
(i)(A) States with EPA-approved MMM program plans shall provide
written reports to EPA in the second and fourth years between initial
implementation of the MMM program and the first 5-year review period,
and in the second and fourth years of every subsequent 5-year review
period.
(B) States that submit a letter to the Administrator by [90 days
after date of publication of the final rule in the Federal Register]
committing to develop an MMM program plan, must submit their first 2-
year report by [6.5 years after date of publication of the final rule
in the Federal Register]. For States not submitting the 90-day letter,
but choosing subsequently to submit an MMM program plan and adopt the
AMCL, the first 2-year report must be submitted to EPA by [5 years
after date of publication of the final rule in the Federal Register].
(ii) These reports are required to include the following
information:
(A) A quantitative assessment of progress towards meeting the
required goals described in Sec. 141.302(b), including the number or
rate of existing homes mitigated and the number or rate of new homes
built radon-resistant since implementation of the States' MMM program,
and
(B) A description of accomplishments and activities that implement
the required program strategies, described in Sec. 141.302(c), outlined
in the implementation plans and in the two required areas of promoting
increased testing and mitigation of existing homes and promoting
increased use of radon-resistant techniques in construction of new
homes.
(C) If goals were defined as rates, the State must also provide an
estimate of
[[Page 59377]]
the number of mitigations and radon-resistant new homes represented by
the reported rate increase for the two-year period.
(D) If the MMM program plan includes goals for promoting public
awareness of the health effects of indoor radon, testing of homes by
the public; testing and mitigation of existing schools; and
construction of new public schools to be radon-resistant, the report is
also required to include information on results and accomplishments in
these areas.
(iii) States shall make available to the public each of these two-
year reports, as well as the EPA summaries of the five-year reviews of
a State's MMM program, within 90 days of completion of the reports and
the review.
(iv) In primacy States without a State-wide MMM program, the States
shall provide a report to EPA every five-years on the status and
progress of CWS MMM programs towards meeting their goals. The first of
such reports would be due by [10.5 years after date of publication of
the final rule in the Federal Register].
* * * * *
4. Section 142.16 is amended by adding new paragraph (i) to read as
follows:
Sec. 142.16 Special primacy requirements.
* * * * *
(i) Requirements for States to adopt 40 CFR part 141, subpart R. In
addition to the general primacy requirements elsewhere in this part,
including the requirement that State regulations be at least as
stringent as federal requirements, an application for approval of a
State program revision that adopts 40 CFR part 141, subpart R, must
contain a description of how the State will accomplish the program
requirements for implementation of the AMCL and MMM program plan or the
MCL as follows:
(1) If a State chooses to develop and implement a State-wide MMM
program plan and adopt the AMCL, the primacy application must include
the following elements:
(i) A copy of the State-wide MMM program plan prepared to meet the
criteria outlined in Sec. 141.302 of this chapter.
(ii) A description of how the State will make resources available
for implementation of the State-wide MMM program plan.
(iii) A description of the extent and nature of coordination
between interagency programs (i.e., indoor radon and drinking water
programs) on development and implementation of the MMM program plan,
including the level of resources that will be made available for
implementation and coordination between interagency programs (i.e.,
indoor air and drinking water programs).
(2) If a State chooses to adopt the MCL the primacy application
must contain the following:
(i) A description of how the State will implement a program to
approve local CWS MMM program plans prepared to meet the criteria
outlined in Sec. 141.302 of this chapter and a description of the
State's authority to implement this program.
(ii) A description of how the State will ensure local CWS MMM
program plans are implemented.
(iii) A description of reporting and record keeping requirements
for local CWS MMM programs.
(iv) A description of how the State will review local CWS program
plans at least every five years to determine if they are implementing
the MMM program and making progress towards their goals.
(v) A description of the procedures and schedule the State will use
in withdrawing State approval of a CWS MMM program plan and notifying
the CWS that they are required to comply with the MCL.
(vi) A description of the extent and nature of coordination between
interagency programs (i.e., indoor radon and drinking water programs)
on development and implementation of the State process for review and
approval of CWS MMM program plans. This description includes the level
of resources that will be made available for implementation and
coordination between interagency programs (i.e., indoor air and
drinking water programs).
(vii) A description of how the State will make required CWS reports
available to the public.
5. A new Sec. 142.65 is added to subpart G, to read as follows:
Sec. 142.65. Variances and exemptions from the maximum contaminant
level for radon.
(a) The Administrator, pursuant to section 1415(a)(1)(A) of the
Act, hereby identifies in the following table as the best technology,
treatment techniques, or other means available for achieving compliance
with the maximum contaminant level for radon:
BAT for Radon-222
1. For all systems: High-Performance Aeration \1\
2. For systems serving 10,000 persons or fewer: High-Performance
Aeration \1\ or \2\, Granular Activated Carbon \2\ (GAC), and Point-of-
Entry GAC \2\.
---------------------------------------------------------------------------
\1\ High Performance Aeration is defined as the group of
aeration technologies that are capable of being designed for high
radon removal efficiencies, i.e., Packed Tower Aeration, Multi-Stage
Bubble Aeration and other suitable diffused bubble aeration
technologies, Shallow Tray and other suitable Tray Aeration
technologies, and any other aeration technologies that are capable
of similar high performance.
\2\ As defined and described in 40 CFR 141.66 (e).
---------------------------------------------------------------------------
(b) A State shall require a community water system to install and/
or use any treatment method identified in paragraph (a) of this section
as a condition for granting a variance, based upon an evaluation
satisfactory to the State that indicates that alternative sources of
water are not reasonably available to the system.
(c) Bottled water and/or granular activated carbon point-of-use
devices cannot be used as means of being granted a variance or an
exemption for radon.
(d) Community water systems that use point-of-entry devices as a
condition for obtaining a variance or an exemption from NPDWRs must
meet the following requirements:
(1) All point-of-entry units shall be owned, controlled, and
maintained by the community water system or by a person or persons
under contract with the public water system to ensure proper operation
and maintenance of the unit under the terms of the variance or
exemption.
(2) All point-of-entry units shall be equipped with mechanical
warning devices to ensure that customers are notified of operational
problems.
(3) If the American National Standards Institute has issued product
standards applicable to a specific type of point-of-entry device for
radon,
[[Page 59378]]
individual units of that type shall not be accepted under the terms of
the variance or exemption unless they are independently certified in
accordance with such standards.
(4) Before point-of-entry devices are installed, the community
water system must obtain the approval of a monitoring plan which
ensures that the devices provide health protection equivalent to
analogous centralized water treatment.
(5) The community water system must apply effective technology
under a State-approved plan. The microbiological safety of the water
must be maintained at all times.
(6) The State must require adequate certification of performance,
field testing, and, if not included in the certification process, a
rigorous engineering review of the point-of-entry devices.
(7) The design and application of point-of-entry devices must
consider the potential for increasing concentrations of heterotrophic
bacteria in water treated with activated carbon. It may be necessary to
use frequent backwashing, post-GAC contactor disinfection, and
Heterotrophic Plate Count monitoring to ensure that the microbiological
safety of the water is not compromised.
6. Section 142.72 is amended by removing the introductory text, by
redesignating paragraphs (a) through (d) as (b)(1) through (b)(4), and
by adding a new paragraph (a) to read as follows:
Sec. 142.72. Requirements for Tribal eligibility.
(a) If a Tribe meets the criteria in paragraph (b) of this section,
the Administrator is authorized to treat an Indian Tribe as eligible to
apply for:
(1) Primary enforcement responsibility for the Public Water System
Program:
(2) Authority to waive the mailing requirements of 40 CFR
141.155(a); and
(3) Authority to develop and implement a radon multimedia
mitigation program in accordance with 40 CFR part 141, subpart R.
* * * * *
7. Section 142.78 is amended by revising paragraph (b) to read as
follows:
Sec. 142.78. Procedure for processing an Indian Tribe's application.
* * * * *
(b) A Tribe that meets the requirements of Sec. 142.72 is eligible
to apply for development grants and primary enforcement responsibility
for a Public Water System and associated funding under section 1443(a)
of the Act, for primary enforcement responsibility for public water
systems under section 1413 of the Act, for the authority to waive the
mailing requirements of 40 CFR 141.155(a), and for the authority to
develop and implement a radon multimedia mitigation program in
accordance with 40 CFR part 141, subpart R.
8. Part 142 is amended by adding a new Subpart L to read as
follows:
Subpart L--Review of State MMM Programs
Sec. 142.400 Review of State MMM programs and procedures for
withdrawing approval of State MMM programs.
(a)(1)At least every five years, the Administrator shall review
State MMM programs. For the purposes of this review, States with EPA-
approved MMM programs shall provide written reports to the
Administrator in the second and fourth years between initial
implementation of the MMM program and the first 5-year review period,
and in the second and fourth years of every subsequent 5-year review
period. The written reports will discuss the status and progress of
their program towards meeting their MMM goals. The Administrator will
use the information provided in the two biennial reports in discussions
and consultations with the State to review the programs to determine
whether they continue to be expected to achieve risk reduction of
indoor radon.
(2) If the Administrator determines that a State MMM program is not
achieving progress towards its MMM goals, the Administrator and the
State shall collaborate to develop modifications and adjustments to the
program to be implemented over the five year period following the
review. EPA will prepare a summary of the outcome of the program
evaluation and the proposed modification and adjustments, if any, to be
made by the State.
(3) If the State repeatedly fails to correct, modify or adjust
implementation of its MMM program after notice by the Administrator,
the Administrator shall initiate proceedings to withdraw approval of
the State's MMM program plan. The Administrator shall notify the State
in writing that EPA is initiating withdrawing a State-wide MMM program
plan and shall summarize in the notice the information available that
indicates that the State is no longer achieving progress towards its
MMM goals.
(4) The State notified pursuant to paragraph (a)(3) of this section
may, within 30 days of receiving the Administrator's notice, submit to
the Administrator evidence that the State plans to implement
modifications to the State MMM program.
(5) After reviewing the submission of the State, if any, made
pursuant to paragraph (a)(4) of this section, the Administrator shall
make a final determination either that the State no longer continues to
achieve progress towards its MMM goals, or that the State continues to
implement modifications to the State MMM program, and shall notify the
State of his or her determination. Before a final determination that
the State no longer continues to achieve progress towards its MMM
goals, the Administrator shall offer a public hearing and will publish
a notice in the Federal Register.
(b) If approval of a State's MMM program is withdrawn, the State
will be responsible for notifying CWSs of the Administrator's
withdrawal of approval of the State-wide MMM program plan. The CWSs in
the State would then be required to comply with the MCL. EPA will work
with the State to establish a State process for review and approval of
CWS MMM program plans that meet the required criteria and a time frame
for submittal of program plans by CWSs that choose to continue
complying with the AMCL. The review process will allow for local public
participation in development and review of the program plan.
[FR Doc. 99-27741 Filed 10-25-99; 3:12 pm]
BILLING CODE 6560-50-P
