[Federal Register Volume 64, Number 246 (Thursday, December 23, 1999)]
[Proposed Rules]
[Pages 72045-72062]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-33033]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 503
[FRL-6513-3]
RIN 2040-AC25
Standards for the Use or Disposal of Sewage Sludge
AGENCY: Environmental Protection Agency.
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
amend management standards for sewage sludge by adding a numeric
concentration limit for dioxin and dioxin-like compounds (``dioxins'')
in sewage sludge that is applied to the land, and monitoring, record
keeping and reporting requirements for dioxins in sewage sludge that is
land applied. Today's action also presents the results of risk
assessments for dioxins in sewage sludge that is applied to the land,
placed in surface disposal units, or incinerated. Based on these risk
assessments, the Agency is not proposing additional numeric standards
or management practice requirements
[[Page 72046]]
for dioxins in sewage sludge that is placed in surface disposal units
or incinerated.
EPA is proposing a standard for dioxins in sewage sludge that is
applied to the land in order to protect public health and the
environment from unreasonable risks of exposure to dioxins. The
Agency's risk assessment for land application of sewage sludge
estimates that sewage sludge with concentrations of dioxins above the
proposed limit may present an unreasonable cancer risk to specific
highly exposed individuals. The purpose of this standard would be to
prohibit land application of sewage sludge containing concentrations of
dioxins above the limit, and thereby protect the health of highly
exposed individuals as well as the health of the general population.
We are also proposing to exclude from the proposed numeric limit
and monitoring requirements treatment works with a flow rate equal to
or less than one million gallons per day and certain sludge-only
entities that receive sewage sludge for further processing prior to
land application. This exclusion is based on the relatively small
amount of sewage sludge that is prepared by these facilities and
entities and, therefore, the low probability that land application of
these materials could significantly increase risk from dioxins to human
health or the environment.
Finally, we are proposing technical amendments to the frequency of
monitoring requirements. These amendments are intended to clarify but,
with one exception, not alter the monitoring schedule in the existing
sludge rule. The one exception would require preparers of material
derived from sewage sludge to determine the appropriate monitoring
schedule based on quantity of material derived rather than quantity of
sewage sludge received for processing.
DATES: Comments must be received or postmarked on or before midnight
February 22, 2000.
ADDRESSES: Written comments and enclosures should be mailed or hand-
delivered to: Part 503 Sewage Sludge Use or Disposal Rule; Docket
Number W-99-18, Comment Clerk, Water Docket MC-4101, Environmental
Protection Agency, 401 M Street, SW, Washington, DC 20460. Comments may
also be submitted electronically to OW-Docket@epamail.epa.gov. For
additional information see Additional Docket Information section below.
FOR FURTHER INFORMATION CONTACT: Arleen Plunkett, U.S. Environmental
Protection Agency, Office of Water, Health and Ecological Criteria
Division (4304), 401 M Street, SW, Washington, DC 20460. (202) 260-
3418.
SUPPLEMENTARY INFORMATION:
I. Regulated Entities
II Additional Docket Information
III. Legal Background
A. Legal Authority Under Which EPA is Proposing to take Action
B. Prior Regulation of Sewage Sludge Use or Disposal Under the
Clean Water Act
IV. Proposed Round Two Sewage Sludge Regulation
A. Selection of Dioxins for Round Two
B. Proposed Requirements for Sewage Sludge That Is Land Applied
1. Overview of Proposed Requirements
2. Definition of Dioxins
3. Analytical Methods
4. Frequency of Monitoring Requirements
5. Small Preparer Exclusion
C. Proposal for Sewage Sludge That Is Placed in a Surface
Disposal Unit or Incinerated in a Sewage Sludge Incinerator
D. Estimate of Costs
V. Risk Assessment Methodologies and Results
A. Approach and Assumptions in EPA's Risk Assessments for
Exposure to Dioxins Resulting from Sewage Sludge Use or Disposal
Practices
B. Description of Land Application Risk Assessment
1. Land Application Exposure Pathways
2. Key Assumptions for the Land Application Risk Assessment
3. Land Application Risk Characterization
C. Description of Surface Disposal Risk Assessment
1. Surface Disposal Exposure Pathways
2. Key Assumptions for the Surface Disposal Risk Assessment
3. Surface Disposal Risk Characterization
D. Description of Incineration Risk Assessment
1. Incineration Exposure Pathways
2. Key Assumptions for the Incineration Risk Assessment
3. Incineration Risk Characterization
VI. Other Options that EPA Considered
A. Numeric Standards for All Use or Disposal Practices
B. Require all Sewage Sludge To Be Landfilled or Surface
Impounded
C. No Further Regulation of Sewage Sludge for any Use or
Disposal Practice
VII. Request for Public Comments
VIII. Regulatory Assessment Requirements
A. Executive Order 12866, Regulatory Planning and Review
B. Regulatory Flexibility Act (RFA), as Amended by the Small
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5
U.S.C. 601 et seq.
C. Paperwork Reduction Act
D. Unfunded Mandate Reform Act
E. Executive Order 13132, Federalism
F. Executive Order 13084, Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045, Protection of Children from
Environmental Health Risks and Safety Risks
H. National Technology Transfer and Advancement Act
X. List of References
I. Regulated Entities
Entities potentially regulated by this proposed action are those
that prepare sewage sludge and/or use or dispose of the sewage sludge
through application to the land. Regulated categories and entities
include:
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Category Examples of regulated entities
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State/Local/Tribal Government.......... Publicly owned treatment works
and other treatment works that
treat domestic sewage, that
prepare sewage sludge and/or
apply sewage sludge to the
land.
Federal Government..................... Federal Agencies with treatment
works that treat domestic
sewage, that prepare sewage
sludge and/or apply sewage
sludge to the land.
Industry............................... Privately-owned treatment works
that treat domestic sewage,
and persons who receive sewage
sludge and change the quality
of the sewage sludge before it
is used or disposed.
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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
could potentially be regulated by this action. Other types of entities
not listed in the table could also be regulated. To determine whether
your facility or company is regulated by this action, you should
carefully examine the applicability criteria in Secs. 503.1 and 503.10
of title 40 of the Code of Federal Regulations. If you have questions
regarding the applicability of this action to a particular entity,
consult the person listed in the preceding FOR FURTHER INFORMATION
CONTACT section.
[[Page 72047]]
II. Additional Docket Information
The record for this rulemaking has been established under docket
number W-99-18 and includes supporting documentation as well as the
printed paper versions of electronic materials. When submitting written
comments to the Water Docket, (see ADDRESSES section above) please
reference docket number W-99-18 and submit an original and three copies
of your comments and enclosures (including references). For an
acknowledgment that we have received your information, please include a
self-addressed, stamped envelope. EPA will not accept facsimiles
(faxes). Comments may also be submitted electronically to: docket@epamail.epa.gov. Electronic comments must be submitted as an
ASCII, WP5.1, WP6.1or WP8 file avoiding the use of special characters
and form of encryption. Electronic comments must be identified by
docket number W-99-18. Comments and data will also be accepted on discs
in WP5.1, WP6.1, WP8, or ASCII file format. To ensure that EPA can
read, understand, and, therefore, properly respond to comments, the
Agency would prefer that commenters cite, where possible, the
paragraph(s) or sections in the notice or supporting documents to which
each comment refers. Commentors should use a separate paragraph for
each issue.
The record is available for inspection from 9:00 am to 4:00 pm
Eastern Standard or Daylight time, Monday through Friday, excluding
legal holidays at the Water Docket, EB 57, USEPA Headquarters, 401 M
Street, SW, Washington, DC 20460. For access to the docket materials,
please call 202-260-3027 to schedule an appointment.
For information on the existing rule in 40 CFR Part 503, you may
obtain a copy of A Plain English Guide to the EPA Part 503 Biosolids
Rule on the Internet at http://www.epa.gov/owm/bio.htm or request the
document (EPA publication number EPA/832/R-93/003) from: Municipal
Technology Branch, Office of Wastewater Management (4204), Office of
Water, U.S. Environmental Protection Agency, 401 M Street, SW,
Washington, DC 20460.
III. Legal Background
A. Legal Authority Under Which EPA Is Proposing To Take Action
EPA is proposing regulatory amendments to 40 CFR part 503 under
section 405(d) and (e) of the Clean Water Act (CWA), 33 U.S.C. 1345(d),
(e). In 1987, Congress amended section 405 and, for the first time, set
forth a comprehensive program for reducing the potential environmental
risks and maximizing the beneficial use of sewage sludge. As amended,
section 405(d) of the CWA requires us to establish numeric limits and
management practices that protect public health and the environment
from the reasonably anticipated adverse effects of toxic pollutants in
sewage sludge. Section 405(e) prohibits any person from disposing of
sewage sludge from a publicly owned treatment works (POTW) or other
treatment works treating domestic sewage through any use or disposal
practice for which regulations have been established pursuant to
section 405 except in compliance with the section 405 regulations.
Amended section 405(d) also established a timetable for the
development of the sewage sludge use or disposal regulations. H. Rep.
No. 1004, 99th Cong. 2d. Sess. 158 (1986). Section 405(d) calls for two
rounds of sewage sludge regulations. The first round required EPA to
establish numeric limits and management practices for toxic pollutants
we identified which, based on ``available information on their
toxicity, persistence, concentration, mobility, or potential for
exposure may be present in sewage sludge in concentrations which may
adversely affect public health or the environment.'' CWA section
405(d)(2)(A). The second round concerns toxic pollutants not regulated
in the first round ``which may adversely affect public health or the
environment.'' CWA Section 405(d)(2)(B).
EPA did not meet the timetable in section 405(d) for promulgating
the first round of regulations, and a citizen's suit was filed to
require EPA to fulfill this mandate. (Gearhart v. Browner, Civ. No. 89-
6266-HO (D. Ore.)). In accordance with the consent decree entered by
the court in this case, EPA promulgated the first round of sewage
sludge regulations, 40 CFR Part 503. 58 FR 9248 (Feb. 19, 1993)
(``Round One''). The consent decree also established a schedule for
identifying additional toxic pollutants in sewage sludge and completing
the second round of regulation under section 405(d)(2)(B) (``Round
Two''). First, in May 1993, EPA identified 31 pollutants not regulated
in Round One that we were considering for regulation. In November 1995,
EPA notified the court that it was revising the original list of 31
pollutants and considering two pollutant groups for the second round:
polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) and dioxin-
like coplanar polychlorinated biphenyls (PCBs). Under the consent
decree as modified by court order signed January 5, 1994, the
Administrator is required to sign a notice for publication proposing
such regulations no later than December 15, 1999, and to sign a notice
taking final action on the proposal no later than December 15, 2001.
B. Prior Regulation of Sewage Sludge Use or Disposal Under the Clean
Water Act
As noted above, CWA section 405(d)(2)(A) required the first round
of regulation to be based on ``available information on [the] toxicity,
persistence, concentration, mobility, or potential for exposure'' of
toxic pollutants in sewage sludge. After extensive consultation, EPA
initially selected a list of some 50 pollutants to analyze. We then
collected available data on those pollutants and developed further
information on their toxicity, persistence, means of transport, and
environmental fate. For 40 pollutants, we also developed preliminary
information on the relative frequency of concentration by analyzing
their concentrations in the sewage sludge of 43 to 45 POTWs in 40
cities, which we presented in the report Fate of Priority Pollutants in
Publicly Owned Treatment Works (the ``40 Cities Study''). Based on this
information and a screening assessment to determine whether any or all
of the pollutants may adversely affect human health or the environment,
we sorted the pollutants into three groups: (1) those which did not
exceed a human health or environmental criterion at the highest
concentrations shown in the 40 Cities Study; (2) those for which we
lacked sufficient data, and (3) those which warranted further risk
analysis for possible regulation under section 405(d)(2)(A) (58 FR
9263-9265).
For the final Round One regulation, we conducted a National Sewage
Sludge Survey (NSSS) (Notice of Data Availability, 55 FR 47210 (Nov. 9,
1990)) (USEPA, 1990). We gathered data from sewage sludge samples taken
at 180 POTWs, as well as survey data from 475 public treatment
facilities with at least secondary wastewater treatment. We designed
the NSSS to produce national estimates of (1) concentrations of toxic
pollutants in municipal sewage sludge, (2) sewage sludge generation and
treatment processes, (3) sewage sludge use or disposal practices and
alternative use or disposal practices, and (4) sewage sludge treatment
and disposal costs. We analyzed the samples of sewage sludge for a
total of 412 pollutants, including every organic, pesticide,
dibenzofuran, dioxin and PCB analyte for which EPA had gas
[[Page 72048]]
chromatography and mass spectrometry (GC/MS) standards (58 FR 9268-
9269).
EPA published the Round One standards (40 CFR part 503) on February
19, 1993. These regulations established requirements for the final use
or disposal of sewage sludge under three circumstances:
When it is applied to the land for a beneficial purpose,
including use in home gardens;
When it is placed in a surface disposal site, including
sewage sludge-only landfills; and
When it is incinerated.
For land application, Part 503 set numeric limits for nine heavy
metals in sewage sludge; established operational standards to reduce or
eliminate pathogens in sewage sludge and to reduce vector attraction;
and established management practices to restrict the application rate
and placement of sewage sludge on the land. Regarding surface disposal,
part 503 set numeric limits for three metals in sewage sludge,
established requirements for the placement and management of a surface
disposal site, and established operational standards to reduce or
eliminate pathogens in sewage sludge and to reduce vector attraction.
For incineration in a sewage sludge incinerator (SSI), part 503
established limits for five pollutants in the sewage sludge fed to a
SSI and adopted standards under the Clean Air Act for two additional
pollutants. We also established performance standards for SSIs through
an operational standard for total hydrocarbon or carbon monoxide
emissions. Part 503 also allows disposal of sewage sludge in a
municipal solid waste landfill in accordance with 40 CFR part 258. The
final rule also requires some monitoring, record keeping and reporting.
Standards apply to publicly- and privately-owned treatment works that
generate or treat domestic sewage sludge and to anyone who uses or
disposes of sewage sludge.
EPA has amended part 503 several times since its initial
publication in February 1993. Following promulgation of the Round One
rule, several petitions for review were filed challenging various
aspects of the rule. In one petition, several mining and chemical
concerns challenged the land application molybdenum limits. EPA amended
Part 503 to delete the cumulative loading rate and pollutant
concentration rate for molybdenum in sewage sludge to be land applied
(59 FR 9095, Feb. 25, 1994). Also in that Federal Register notice, EPA
added continuous monitoring of carbon monoxide as an alternative to
continuous monitoring of total hydrocarbons in the sewage sludge
incinerator requirements. In another case, Leather Industries of
America v. EPA, 40 F.3d 392 (D.C. Cir. 1994), the court remanded
several of the land application requirements. As a result of that
decision, EPA deleted all numerical standards for chromium in sewage
sludge to be land applied and adjusted the Table 3 limit for selenium.
(60 FR 54764, Oct. 25, 1995). EPA is considering further amendments to
address the issues remaining from the partial remand as well as other
issues. EPA most recently amended part 503 to make a number of
technical amendments, provide some regulatory flexibility, and make the
sewage sludge incinerator standards self-implementing. (64 FR 42552,
Aug. 4, 1999).
For a detailed discussion of the Part 503 Rule, see A Plain English
Guide to the EPA Part 503 Biosolids Rule, which is available as stated
in the ADDRESSES section of this preamble.
IV. Proposed Round Two Sewage Sludge Regulation
A. Selection of Dioxins for Round Two
Chlorinated dioxins are unintentional byproducts of certain
manufacturing processes and incomplete combustion of organic waste.
Dioxins are not created in the sewage treatment process; rather,
treatment works concentrate those dioxins that enter the sewage
treatment system from other sources. Dioxins present in the influent to
a wastewater treatment works are partially concentrated in sewage
sludge and partially discharged in the effluent. The few sewage
treatment works that incinerate sewage sludge may generate small
amounts of dioxins and coplanar PCBs during the process of combustion.
Dioxins are biologically active organic compounds that cause a variety
of health impacts on mammalian species, including humans, at very low
and chronic doses. They are found in extremely small quantities in air,
water and soil; however, they are persistent in the environment and
bioaccumulate in the foodchain. (USEPA, 1994)
As described in Section III.B above, when EPA undertook the 40
Cities Study, we identified one group of pollutants, for which we
lacked sufficient data. That group included polychlorinated dibenzo-p-
dioxins and polychlorinated dibenzofurans.
In the subsequent National Sewage Sludge Survey (NSSS) (EPA 1990),
we obtained additional data, which we used to perform an initial
statistical screening of 412 additional toxic pollutants detected in
sewage sludge. We then reviewed the scientific literature for toxicity,
fate, effect, and transport information for the pollutants identified
in the initial screening. We decided what pollutants to consider for
possible regulation by comparing the calculated levels associated with
adverse effects to the actual level and occurrence data from the NSSS.
The screening yielded a list of 31 pollutants or pollutant groups
to be considered for the future regulation. We then conducted a
Comprehensive Hazard Identification Study (USEPA, 1996), a screening
type analysis that included dose-response evaluation, exposure
assessment, and risk characterization. Our goal for the study was to
identify pollutants that, based on very conservative or worst case
assumptions, might pose human health risks for a hypothetical
individual with the greatest possible exposure through any of ten
pathways. Based on this evaluation, we considered further assessment
and possible regulation for dioxins/dibenzofurans and coplanar PCBs
only.
B. Proposed Requirements for Sewage Sludge That Is Land Applied
1. Overview of Proposed Requirements
Today's action proposes to amend 40 CFR 503.8, 503.9, 503.10,
503.13, and 503.16 to prohibit land application of sewage sludge that
contains greater than 300 parts per trillion (ppt) toxic equivalents
(TEQ) of dioxins. This proposed numeric standard would be expressed as
0.0003 milligrams TEQ per kilogram dry sewage sludge in
Sec. 503.13(b)(1) and (b)(3), Tables 1 and 3. See Section V.B. below,
for an explanation of the risk assessment and how EPA determined that a
limit of 300 ppt TEQ dioxins in sewage sludge that is land applied is
protective of public health and the environment.
We are proposing to define ``dioxins'' to mean 29 specific
congeners of polychlorinated dibenzo-p-dioxins, polychlorinated
dibenzofurans, and coplanar PCBs. Today's proposed rule also requires
monitoring, record keeping, and reporting to ensure that this numeric
limit (300 ppt TEQ) is met. The proposal specifies two analytical
methods that would be used to analyze sewage sludge to determine the
level of dioxins/dibenzofurans and coplanar PCBs in sewage sludge. The
Agency is proposing two alternative monitoring schedules based on the
level of dioxins measured in sewage sludge. EPA is also proposing to
exclude from compliance with the standards for dioxins and the
monitoring requirement, treatment works that treat domestic sewage and
[[Page 72049]]
that have a flow rate of one million gallons per day or less and
certain small entities that derive material from sewage sludge received
from sewage treatment works (``sludge-only entities''). These proposed
provisions are discussed in detail in the following sections.
2. Definition of Dioxins
The proposal includes a definition of ``dioxins'' to specify the
seven 2,3,7,8,-substituted congeners of polychlorinated dibenzo-p-
dioxins (PCDDs), the ten 2,3,7,8-substituted congeners of
polychlorinated dibenzofurans (PCDFs), and the twelve coplanar PCB
congeners to which the numeric standard applies. The vast majority of
information on the toxicity of dioxins relates to the congener 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD). Animals exposed to 2,3,7,8-TCDD
exhibit a variety of biological responses and adverse effects. These
include both carcinogenic and non-carcinogenic effects. These effects
are primarily classified as chronic effects and consequently they are
generally associated with long term exposure over years and decades.
Relatively speaking, these exposures and effects are observable at very
low levels in the laboratory and in the environment when compared with
other environmental toxicants (USEPA, 1994).
Studies to elucidate the mechanism of toxicity for 2,3,7,8-TCDD in
mammalian species have indicated that the overall shape and chlorine
substitution of this congener are keys to its biological potency. The
fact that all of the lateral positions (the 2,3,7,8 positions) on the
multi-ring system are substituted with chlorine and that the overall
molecule assumes a flat or planar configuration apparently are
essential factors that make this congener biologically active. Other
congeners with a similar structure and chlorine substitution pattern
are assumed to exhibit similar biological properties. These include the
other six 2,3,7,8-chlorinated substituted dibenzo-p-dioxin congeners,
the ten 2,3,7,8-chlorinated substituted dibenzofuran congeners and the
12 coplanar PCB congeners. Coplanar PCB congeners are those congeners
with no more than one ortho position and both para positions
substituted with chlorine in the biphenyl ring system and the molecule
assumes a relatively planar (i.e. flat) configuration.
The 300 ppt TEQ numeric limit would apply to these 29 congeners in
ppt TEQ or nanograms TEQ per kilogram of dry sewage sludge. The TEQ
concentration is calculated by multiplying the concentration of each
congener in the sewage sludge by its corresponding ``toxicity
equivalent factor,'' or TEF, and then summing the resulting products
from this calculation for all 29 congeners. The TEF schemes to be used
are the International scheme described in USEPA, 1989, for the 17
2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and
polychlorinated dibenzofurans and the World Health Organization's TEF
scheme (Van den Berg, 1998) for the 12 coplanar PCBs. We invite comment
on the this proposed definition of dioxins.
3. Analytical Methods
EPA is proposing two methods for analyzing dioxins in sewage sludge
to be land applied. One method, EPA Method No. 1613, Revision B (1613B)
would be required for monitoring for the seven dioxin and ten
dibenzofuran congeners. EPA Method No. 1668 would be required for the
12 coplanar PCB congeners.
EPA proposes to use Method 1613, Revision B, ``Tetra-Through Octa-
Chlorinated Dioxins and Furans by Isotope Dilution HRGC/HRMS.'' Method
1613B is an approved test method (40 CFR part 136) for use in EPA's
wastewater program for determining dioxins and furans. This test method
is applicable to both aqueous and solid samples, but was fully
validated through an interlaboratory study prior to its promulgation
only for use in wastewater. Method 1613B has not been approved in part
136 for sewage sludge (62 FR 48394, Sept. 15, 1997).
EPA proposes to use Method 1668, ``Chlorinated Biphenyl Congeners
in Water, Soil, Sediment, and Tissue by HRGC/HRMS.'' Method 1668 was
developed by EPA to analyze coplaner PCBs in a variety of matrices,
including sewage sludge. Method 1668 was validated in a single
laboratory and tested in a second laboratory. These data were published
in the draft method ``Toxic Poly-Chlorinated Biphenyls by Isotope
Dilution High Resolution Gas Chromatography/High Resolution Mass
Spectrometry,'' EPA-821-R-97-001, March 1997. EPA revised the original
version of this method to address additional PCB congeners. Method
1668A is the state-of-the-art test method for the measurement of PCB
congeners, including coplanar PCBs; however it is still in draft.
Method 1668A was validated in a single laboratory and peer reviewed by
21 laboratories, including EPA's laboratory in Bay St. Louis,
Mississippi. Although Method 1668A has not gone through a full
interlaboratory validation study yet, EPA has used this test method in
monitoring surveys. Both Method 1668 and 1668A are in the docket for
this rulemaking. If EPA finalizes Method 1668A before EPA takes final
action on this proposed rulemaking, then the final rule would require
use of Method 1668A. However, because Method 1668A is not final at this
time, EPA is proposing the original version of Method 1668 to be used
to analyze coplanar PCBs in sewage sludge.
EPA requests public comment on the use of these two test methods
for compliance with monitoring requirements for sewage sludge. EPA also
specifically requests comment on the use of Method 1668A for coplanar
PCBs.
4. Frequency of Monitoring Requirements
As stated above, EPA is proposing two alternative monitoring
schedules based on the level of dioxins in sewage sludge to be land
applied. According to existing information on the amounts of dioxins
present in sewage sludge, levels can vary considerably from one source
to another. However, we believe that the level of dioxins in sewage
sludge, both nationally and from specific sources, is relatively
constant over time and may possibly be decreasing (U.S. Conference of
Mayors, 1999). This observation is derived from comparisons of dioxin
concentrations found in the 1988 NSSS (USEPA, 1990) and the more recent
Association of Metropolitan Sewerage Agencies (AMSA) survey (Green, et.
al., 1995), together with anecdotal information from several locations.
We therefore believe it is appropriate to establish two monitoring
schedules for dioxins in Sec. 503.16, depending upon the level of
dioxins found in the initial two years of testing of the sewage sludge.
Treatment works and other sewage sludge preparers (defined in
Sec. 503.9(r)) that find the level of dioxin in their sewage sludge to
be between 300 ppt TEQ and 30 ppt TEQ would be required to monitor
annually. Treatment works and sludge preparers that measure dioxin
levels of 30 ppt TEQ or less for two consecutive years would be
required to monitor every five years thereafter.
We selected 30 ppt TEQ as the level to allow less frequent
monitoring since it is a full order of magnitude less than the proposed
numeric standard of 300 ppt TEQ (i.e., one-tenth). Given the observed
trends described above, we believe it is unlikely that sewage sludge
with 30 ppt TEQ or less will exceed the 300 ppt TEQ limit. This
observation is consistent with: (1) our assumption that dioxins
primarily enter sewage treatment facilities from diffuse background
sources which inherently are less subject to short-term spikes in
[[Page 72050]]
pollutant levels than point sources, and (2) a significant measured
reduction in air emissions of dioxins, which are the principal
contributors to these diffuse sources, according the Agency's United
States Dioxin Inventory (USEPA, 1998). Furthermore, any health risks
associated with dioxin exposure from land application of sewage sludge
would not be significantly affected over a short period of time such as
five years, but rather would require long-term exposure at these levels
to potentially present unreasonable health risks. For these reasons we
believe a five-year monitoring frequency is appropriate for sewage
sludge which was last measured at or below 30 ppt TEQ. We are
specifically requesting comments and additional data on the validity of
our assumptions concerning rates and degree of changes in levels of
dioxins in sewage sludge and the reasonableness of the proposed
monitoring schedule.
A treatment works or other person who prepares sewage sludge for
land application would be able to switch to the reduced monitoring
schedule if tests show that its sewage sludge contained 30 ppt TEQ or
less in two consecutive annual tests. We believe that two consecutive
annual tests are reasonable in order to ensure that the level of
dioxins in the sewage sludge is consistently at or below the 30 ppt TEQ
level. This is consistent with the existing provision in
Sec. 503.16(a)(2), which allows the permitting authority to reduce the
frequency of monitoring after sewage sludge has been monitored for two
years. We are proposing these frequency of monitoring requirements for
dioxins to be in a new paragraph (a)(3) in Sec. 503.16. We also
specifically request comments on whether two consecutive years of
monitoring results under 30 ppt TEQ should be required before allowing
a reduced monitoring schedule.
We are also proposing to amend Sec. 503.16(a) to clarify, but not
alter, existing frequency of monitoring requirements. We propose to
separate the existing requirements contained in Sec. 503.16(a)(1) into
two paragraphs, (a)(1) and (a)(2). Paragraph (a)(1) would contain the
requirements for monitoring concentrations of pollutants except
dioxins, and paragraph (a)(2) would contain the requirements for
monitoring compliance with pathogen reduction and vector attraction
reduction requirements. Existing Sec. 503.16(a)(2) would be renumbered
as Sec. 503.16(a)(4), but would be otherwise unchanged. These
amendments are solely for the purpose of clarity and for expressing
existing regulatory requirements in plain language, and they are not
intended to reopen these requirements for comment. We invite comment on
whether these proposed amendments unintentionally change the substance
of the frequency of monitoring provisions currently in
Sec. 503.16(a)(1).
Finally, we are proposing to amend footnote 1 to Table 1 in
Sec. 503.16. Currently this footnote states that a person who prepares
material derived from sewage sludge received from another preparer must
determine the frequency of monitoring based on the quantity of sewage
sludge received. Sewage sludge is often mixed with other materials to
produce the material derived from sewage sludge that is ultimately
applied to the land. We believe that the frequency of monitoring should
be based on the quantity of product that is actually applied to the
land. We therefore propose to amend the footnote to Table 1 to require
the monitoring schedule to be based on the amount of sewage sludge or
material derived from sewage sludge to be land applied.
5. Small Preparer Exclusion
We are proposing in today's action to exclude from the proposed
requirements relating to dioxins, sewage treatment works with a
wastewater flow of one million gallons per day (MGD) or less and
sludge-only entities which prepare 290 dry metric tons or less of
sewage sludge annually for land application. We estimate that a one MGD
treatment works produces approximately 290 dry metric tons of sewage
sludge annually. Sewage sludge from these small preparers would be
excluded from the limitation on dioxins in sewage sludge; thus these
small preparers would not be required to monitor for dioxins. Such
preparers could continue to land apply their sewage sludge with no
further restriction due to the sludge's dioxin content. Septage pumpers
and haulers would also not be required to comply with the limitation on
dioxins and the associated monitoring requirements. (See 58 FR 9362 for
a discussion of requirements applicable to septage haulers and under
part 503.)
We believe that this exclusion is appropriate for several reasons.
First, the vast majority of land-applied sewage sludge is produced by
sewage treatment works with flow rates higher than one MGD. According
to the 1988 NSSS, treatment works with flow rates of one MGD or less
produce only 135,911 dry metric tons of sewage sludge annually for land
application, or less than eight percent of the total sewage sludge that
is land applied on an annual basis. Of the amount of land applied
sewage sludge produced by those small treatment works, we estimate
approximately 6800 dry metric tons (5%) contained in excess of the 254
ppt TEQ PCDD and PCDF. This estimate is based on PCDD and PCDF only
since the NSSS did not measure coplanar PCBs. Our data indicates that
sewage sludge containing 300 ppt TEQ dioxins typically would have 254
ppt TEQ PCDD and PCDF (USEPA, 1990; Green, et al., 1995). Second, the
probability that this small amount of sewage sludge (i.e., 42 dry
metric tons per facility annually) could unreasonably increase health
risks for any individual is extremely small. As further explained in
Section V.B. of this preamble, the risk assessment assumes a much
greater amount of sewage sludge is applied to the same piece of land
over a long period of time. At this much higher application rate, the
risk assessment estimates unacceptable increase in cancer risk only to
``high-end'' receptors. We have, therefore, concluded that the amounts
of land-applied sewage sludge with dioxins in excess of 300 ppt TEQ
produced by a treatment works with a flow rate of one MGD or less or by
small sludge-only entities does not pose an unreasonable risk. We
request comment on our proposal to exclude small preparers from the
limit for dioxins in sewage sludge to be land applied. We specifically
invite comment on our proposal to exclude small entities which receive
and further process sewage sludge prior to land application. We also
specifically invite comment on how we propose to define such small
entities.
We are, however, reserving the option of requiring initial
monitoring and applying the limit for dioxins for small preparers
(treatment works and sludge-only entities) which land apply sewage
sludge. We are requesting information on the dioxin content and land
application practices (e.g., annual application rates, numbers and
sizes of sites and the number of applications per site) for sewage
sludge from treatment works with a flow rate of one MGD or less. We
specifically invite public comment on whether the Agency should
promulgate such a requirement.
We are also proposing to exempt septage pumpers and haulers from
the proposed limit for dioxins. Septage pumpers and haulers are
generally small businesses. A typical septage pumper and hauler removes
between 500 and 1,000 gallons of septage from a residential septic or
holding tank once every three to five years. The typical maximum
capacity of a septic tanker that is hauling septage for land
application is between 2,000 and 4,000
[[Page 72051]]
gallons. The solids content of septage is less than five percent. Using
the same reasoning as that for sewage treatment works with flows of one
MGD or less, the maximum amount of septage solids that could be land
applied on any given area of land on an annual basis would be small.
Even if this septage contained in excess of 300 ppt TEQ dioxins on a
dry matter basis, the quantity of dioxins being land applied would be
insignificant.
C. Proposal for Sewage Sludge That Is Placed in a Surface Disposal Unit
or Incinerated in a Sewage Sludge Incinerator
EPA is proposing to take no action to regulate current surface
disposal or incineration practices for dioxins. As explained below in
Sections V.C. and D., we do not predict an unreasonable risk of adverse
effects to human health from cancer as a consequence of either
placement in a surface disposal unit or incineration in a sewage sludge
incinerator. Therefore, no additional numeric limit or operational
standard or monitoring is being proposed for part 503, subparts C and
E. We invite comment on proposing no action to regulate dioxins in
sewage sludge that is placed in a surface disposal unit or incinerated
in a sewage sludge incinerator.
D. Estimate of Costs
The increased costs which would be imposed by this proposed
regulation are the costs for initially monitoring for dioxins by all
land applying treatment works greater than one MGD, annual monitoring
at those facilities with dioxin levels between 30 ppt TEQ and 300 ppt
TEQ, and switching to co-disposal with municipal solid waste for
current land appliers whose sewage sludge contains over 300 ppt TEQ of
dioxins. We assume that the cost of measuring dioxins in sewage sludge
is $2000 per sample and the cost to switch to co-disposal with
municipal solid waste is $189 per dry metric ton in 1998 dollars. We
estimate that the annualized cost of this regulation nationwide would
be approximately $18 million. Of this amount, 13 percent is for
monitoring, and the balance is for switching use or disposal practices.
The permitting authority, whether Federal or State, should not
accrue any significant permitting burden as a result of these proposed
part 503 amendments. The part 503 standards were designed to be self
implementing and independently enforceable in the absence of a Federal
permit. These proposed amendments merely add an additional numerical
standard to the original part 503 rule which was promulgated in 1993.
V. Risk Assessment Methodologies and Results
A. Approach and Assumptions in EPA's Risk Assessments for Exposure to
Dioxins Resulting from Sewage Sludge Use or Disposal Practices
The four steps of the risk assessment process include hazard
identification, dose-response assessment, exposure assessment, and risk
characterization. We conducted risk assessments for land application of
sewage sludge, surface disposal of sewage sludge, and incineration of
sewage sludge in a sewage sludge incinerator. All three risk
assessments used the same hazard identification and dose-response data
and assumptions. However, the risk assessments examined different
exposure pathways and have different risk characterizations. The
following presents an overview of the approach used for these risk
analyses and a general description of the assumptions common to all
three risk assessments.
Today's proposal is based on assessments of the risks to human
health posed by dioxins that might be in sewage sludge or sewage sludge
incinerator emissions using a deterministic risk analysis. A
deterministic risk analysis produces a point estimate of risk or hazard
for each person based on using a single value for each parameter in the
analysis. A parameter is any one of a number of inputs or variables,
such as soil to plant dioxin uptake coefficients, required for the fate
and transport and exposure models and equations that EPA uses to assess
risk. In some cases EPA selects a single set of multiple parameters for
the purpose of conducting our analyses. We do this to prevent
inadvertently combining parameters in our analyses in ways that are
unrealistic. For example, EPA treats environmental setting (location)
parameters such as climate, depth to groundwater, and aquifer type as a
single set of parameters. We believe that, for example, allowing the
climate from one location to be paired with the depth to groundwater
for another location could result in a scenario that would not occur in
nature.
EPA conducts both ``central tendency'' and ``high end''
deterministic risk assessments to attempt to quantify the potential
cancer risk for the ``average'' person in the population (the central
tendency risk) and the risk or hazard for individuals in small, but
definable ``high end'' segments of the population (the high end risk).
For central tendency deterministic risk analyses, we set all parameters
at their central tendency values. For the sewage sludge risk
assessments, the central tendency values generally are either mean
(average) or 50th percentile (median) values.
We use high end deterministic risk analysis to estimate potential
risks and hazards for those individuals exposed at the upper range of
the distribution of exposures. EPA's Guidance For Risk Characterization
(USEPA, 1995) advises that ``conceptually, high end exposure means
exposure above about the 90th percentile of the population
distribution, but not higher than the individual in the population who
has the highest exposure,'' and recommends that ``the assessor should
approach estimating high end by identifying the most sensitive
variables and using high end values for a subset of these variables,
leaving others at their central values.'' For the sewage sludge high
end deterministic risk analyses, EPA used exposure pathways that we
consider to represent how people may encounter the most potential
exposure to dioxin; chose the 95th percentile concentration (USEPA,
1999e) of dioxins in sewage sludge and the highest dioxin emitting
incinerators; and used one other high end exposure factor from the
Agency's Exposure Factors Handbook (USEPA, 1997) to perform a
conservative public health analysis.
The hazard identified for these risk assessments is cancer as a
human health endpoint from the compounds assessed. We took into account
the impacts on human cancer risk nationwide. We examined the cancer
toxicity of 2,3,7,8-TCDD and estimated several dose-response
relationships for this congener (USEPA, 1994). The toxicity of the
other congeners included in the current risk assessment are expressed
in relation to the cancer toxicity of 2,3,7,8-TCDD using guidance we
published (USEPA, 1989) and from information published in the
scientific literature (Van den Berg, et. al., 1998).
Regarding exposure pathways, our evaluation of land application
considered, among other things, risks of human exposure to dioxins
through (a) inhaling or ingesting soil fertilized with sewage sludge,
(b) eating crops grown on this soil or animal products from livestock
grazed on this soil, and (c) ingesting ground or surface water or
edible aquatic organisms contaminated as a result of applying sewage
sludge to land. For surface disposal of sewage sludge, we evaluated the
human health risks associated with drinking ground water contaminated
by dioxins or breathing air affected by volatilized dioxins. For
incineration in a sewage
[[Page 72052]]
sludge incinerator, we evaluated human exposure to dioxins directly
through inhalation of gases and particles in the emissions from sewage
sludge incinerators and indirectly by consumption of crops and animal
products produced on agricultural lands and home gardens affected by
the deposition of particles from sewage sludge incinerator emissions.
We were unable to assess the ecological effects for any of the
practices due to the scarcity of relevant information and evaluation
methods.
As indicated above, we attempted to assess the risk both for
average exposed individuals (AEI) in the population and high end
exposed individuals (HEI) in the population. In these analyses for the
hypothetical AEI, average values were used for all parameters to
capture average risk. For the hypothetical HEI, no more than two high
end values for exposure variables, such as ingestion rates and
inhalation rates, were used in the assessment to estimate high end
risk. These values were obtained in large part from EPA's Exposure
Factors Handbook (USEPA, 1997).
You will find below descriptions of routes of exposure (called the
exposure pathways) through land application, surface disposal, and
incineration of sewage sludge that we assessed. We then calculated
risks associated with these pathways by comparing exposures with dose-
response information for the pollutants. The Technical Support
Documents for this rule making (USEPA, 1999b; USEPA, 1999c; USEPA,
1999d) contain more details on the final comprehensive exposure pathway
analyses, including the modeling algorithms and default parameters as
well as descriptions of major uncertainties and variability.
Agency experts reviewed the risk assessments used for land
application and surface disposal. EPA will submit these risk
assessments to an external peer review panel in accordance with the
Agency's Peer Review Guidelines during the public comment period for
this proposed rule. The risk assessment used for incineration was
submitted to an external peer review panel in accordance with the
Agency's Peer Review Guidelines. We will consider and address peer
review comments and public comments on these risk assessments.
B. Description of Land Application Risk Assessment
We evaluated both agricultural and non-agricultural application
sites associated with the land application pathways. Agricultural
sites, which include rangeland and pasture, are land on which a food,
feed, or fiber crop is grown. Non-agricultural sites include
reclamation, public contact, and forest sites. The term ``reclamation
sites,'' defined in 40 CFR 503.11(n), refers to drastically-disturbed
land that is reclaimed using sewage sludge, including strip mines and
construction sites. ``Public contact sites'' are those that people
frequent where contact is likely. Examples of public contact sites are
parks, ball fields, cemeteries, plant nurseries, turf farms, and golf
courses (40 CFR 503.11(l)).
1. Land Application Exposure Pathways
We considered 15 exposure pathways for land application of sewage
sludge. Five of these pathways were not evaluated since there was
insufficient data. The pathways that were not evaluated included
exposure and subsequent toxicity risks from ingestion of feedstuffs
grown on sewage sludge-amended soils and fed to domesticated farm
animals (animals commercially produced for human consumption), exposure
and subsequent toxicity risks from incidental ingestion of sewage
sludge-amended soils by domesticated farm animals during pasturing and
grazing, phytotoxicity effects from dioxins in sewage sludge-amended
soils, and exposure of soil macro organisms and their animal predators
to dioxins from sewage sludge-amended soils. We invite public comment
and any information regarding the exposure pathways not evaluated in
the land application risk assessment.
Exposure pathways that we fully evaluated for exposure to dioxins
from land application of sewage sludge include:
Consumption of commercially grown crops by the general
population
Consumption of home-grown crops by home gardeners
Incidental ingestion of sewage sludge-amended soil by
children
Consumption of locally produced meat and dairy products by
families living outside urban areas (taking into account both forage
fed to the animals and incidental ingestion of soil by the animals)
Inhalation of dust from sewage sludge-amended soils by
farm workers
Consumption of groundwater, surface water, and aquatic
organisms affected by leachate and runoff from sewage sludge-amended
soil
Inhalation of volatilized pollutants from sewage-sludge
amended soil
And ingestion of breast milk by infants in families living
outside of urban areas
2. Key Assumptions for the Land Application Risk Assessment
As stated above, we evaluated pathways which represent ways in
which people can be most exposed to dioxin, in combination with a
concentration of 300 ppt TEQ of dioxins in sewage sludge and one other
conservative exposure factor, to ensure a true high-end deterministic
risk assessment. Some of the exposure factors for land application were
more conservative than those used for similar incineration pathways. We
did this because nationwide there are 145 known sewage treatment works
with sewage sludge incinerators compared to an estimated 4,250 land
application operations. We estimated the highest concentrations of
dioxins for land applied sewage sludge from a statistically valid
sampling of sewage sludge nationwide, while we were able to identify
and directly monitor the highest dioxin emitting incinerators for this
risk assessment.
For land application, we assumed that the highly exposed individual
lives on the same site for 58 consecutive years. We also assumed that
sewage sludge at the 95th percentile of concentration of dioxins of 300
ppt TEQ as estimated in the NSSS and in a data base from a survey
conducted by the Association of Metropolitan Sewerage Agencies (AMSA)
(Green, et. al., 1995) is applied to the land every other year for 100
years at the rate of 10 metric tons per hectare. We note that the AMSA
survey analyzed for only four of the 12 twelve coplanar PCB congeners.
However, three of these congeners typically dominate the coplanar PCB
TEQ values in most environmental samples and are considered adequate
for generalizing dioxin-like coplanar PCB risk in support of this
proposed rule. For assessing risks from individual facilities and for
complying with the provisions of this proposed rule, a full 12 congener
coplanar PCB analysis is required.
The risk assessment also assumes that land-applied sewage sludge is
incorporated into the soil to a depth of 15 centimeters. Our assumption
is that incorporation into the soil occurs either mechanically at the
time of application or ``naturally'' over time due primarily to the
effects of weather and the activity of soil organisms such as worms and
grubs. The pathways which are based on direct ingestion by grazing
animals or humans assume that a sludge-soil mixture is ingested. The
existing part 503 regulation requires a 30-day waiting period prior
grazing animals after sludge application. We are requesting comment on
whether we should require
[[Page 72053]]
mechanical incorporation of sewage sludge into the soil, whether 30
days is a sufficient waiting period to assure adequate natural
incorporation into the soil, or whether the rule should require a
longer waiting period.
Other key assumptions include the following:
Crops grown on sewage sludge-amended soil are 2.5% of the
lifetime diet for the general population.
For a family living in a rural area, 10% of their beef
diet, 10% of their beef liver diet, 10% of their lamb diet, and 3% of
their dairy diet comes from local farms that raise animals on sewage
sludge amended soils.
Produce grown on sewage sludge-amended soil are 43% to 59%
of a home gardener's diet.
Children from ages 1-6 incidentally ingest 0.4 gram of
sewage sludge-amended soil daily.
People consume two liters of water and 39 grams of aquatic
organisms daily from the same source over their lifetimes.
The nursing period for infants is six months.
All of the assumptions for the land application risk assessment and
the basis for these assumptions are described in the land application
Technical Support Document (TSD) (USEPA, 1999b).
3. Land Application Risk Characterization
The risk assessment for the exposure pathways described above
estimates high end risks. Given these conservative assumptions, the
highest exposure pathways for the hypothetical highly exposed
individuals for land application are rural families which consume
products made from locally raised livestock that incidentally ingest
sewage sludge-amended soil and nursing infants having breast milk from
hypothetically highly exposed rural family mothers. The resulting high
end estimate of cancer risk for any such person is 1.7 per 100,000 (1.7
x 10-5), which is well within the Agency's range of
acceptable risk of one in one million to one in ten thousand (1 x
10-6 to 1 x 10-4). However, we estimate that a
very small percentage of the sewage sludge produced nationwide may
exceed 300 ppt TEQ dioxin. In order to ensure that any risks associated
with land application of sewage sludge remain negligible, we propose to
place a numeric limit of 300 ppt TEQ on the concentration of dioxins in
sewage sludge which is land applied.
C. Description of Surface Disposal Risk Assessment
Sewage sludge surface disposal facilities are of two types: (1)
monofill and (2) surface impoundment. The monofill is a sewage sludge-
only trench fill receiving dewatered sludge with a solids content
greater than 20%. The surface impoundment receives a continuous inflow
of sewage sludge with a low solids content of between 2% and 5%. Both
of these types of surface disposal facilities were subjected to the
risk assessment for dioxins. The surface impoundment clearly offered
the greater potential to emit dioxins to the environment and
subsequently expose an individual to these pollutants. The results of
the risk assessment with estimated incremental risks to the highly
exposed individual are based, therefore, on the surface impoundment.
1. Surface Disposal Exposure Pathways
The only two possible exposure pathways to an HEI are
volatilization of dioxins from the facility with subsequent inhalation
of these pollutants and the leaching of dioxins to groundwater with
subsequent consumption of this groundwater. Based on the required
management practices of these facilities, there is an insignificant
chance that dioxins would be released to surface waters even during
extreme wet weather conditions. Food chain pathways which are critical
in the land application risk assessment are not relevant.
2. Key Assumptions for the Surface Disposal Risk Assessment
The HEI for exposure to surface disposal facilities is a person who
resides in immediate proximity (within 150 meters) to the site. We
assumed that this person spends his/her entire life at this site. We
also assumed that this person inhales outdoor air from this site 16
hours per day and indoor air from within his/her residence adjacent to
this site for eight hours per day. We set water consumption at two
liters per day of groundwater obtained within 150 meters from the edge
of this site at an assumed depth to groundwater of one meter. We
assumed moderately porous soils for the surface impoundment with no
synthetic liner to retain leachate (USEPA, 1999a).
3. Surface Disposal Risk Characterization
The maximum incremental cancer risk to the HEI did not exceed one
in ten million (1 x 10-7) for either exposure pathway
(USEPA, 1999b). Dioxins have extremely low volatility and would not be
expected to offer significant exposure to the HEI through inhalation.
Also, dioxins do not dissolve readily in water. Even in the absence of
a liner, combined with high porosity soil and a short distance to
ground waters as assumed in the risk assessment, only insignificant
amounts of dioxins could ever reach the groundwater. For these reasons,
we are proposing no action to regulate dioxins for sewage sludge
surface disposal.
D. Description of Incineration Risk Assessment
We used four steps to estimate risks from firing sewage sludge in
sewage sludge incinerators. First, we estimated the rate at which
pollutants are emitted from incinerator stacks. Next, we estimated the
movement of pollutants in air near incinerators, including how much
pollutant plumes overlap. We then overlaid maps of expected ground-
level concentrations of pollutants and human populations. Finally, we
determined the extent and nature of resulting health risks of human
exposure to emitted dioxins.
The last step was a multi-pathway risk assessment for exposure to
dioxins that result from the firing of sewage sludge in a sewage sludge
incinerator. The risk assessment estimated hypothetical average and
high end risks to the highly exposed sub-populations of farmers and
home gardeners. We evaluated the risk to the hypothetical highly-
exposed individual who is exposed by both a direct route like
inhalation and other routes through eating contaminated food. In
addition, we conducted a probabilistic analysis of uncertainty for the
home gardener and for the farmer to quantify uncertainty and estimate
the range of calculated risks possible for the facilities modeled.
We considered multiple hearth units without afterburners to be the
worst case technology for sewage sludge incineration and likely the
highest emitters of dioxins and coplanar PCBs. To provide a high end to
estimate of the risk from sewage sludge incineration, the analysis
focused on the six highest emitting incinerators for dioxins/
dibenzofurans and coplanar PCBs in the United States from an initial
screen of 135 incinerators.
1. Incineration Exposure Pathways
The assessment considered, but did not evaluate, all 15 exposure
pathways considered in the land application risk assessment. We
evaluated those pathways expected to result in the highest risk
estimates for which data were available. We selected two exposure
scenarios to represent highly exposed sub-populations that reside
[[Page 72054]]
near sewage sludge incinerators: (1) beef and dairy farmers consuming,
at recreational fisher levels, fish caught near sewage sludge
incinerators, and (2) home gardeners consuming as a portion of their
diet home-grown produce grown near a sewage sludge incinerator. For
both scenarios, we estimated average and high end exposures for
children and adults at locations where they are expected to reside. We
used a geographical information system to identify land uses and
terrain around facilities, to identify watershed and water body
parameters to estimate fish and drinking water ingestion risks, and to
provide census information about farmers and residents exposed to
incinerator emissions. We estimated numbers of individuals exposed and
the associated risks for six population age groups.
2. Key Assumptions for the Incineration Risk Assessment
Many important factors in estimating exposure vary from one
facility to the next, and as a result, the highest emitting facility
will not always produce the highest risk. We therefore selected the six
highest emitting incinerators that also resulted in the highest
potential inhalation exposures from the initial screening assessment of
135 incinerators. The variables that are important for exposure
assessment and considered in the screen include, for example, distance
to exposed population, activities of the exposed population, effective
release height of pollutants, and meteorological conditions. We also
considered emission rates, emission release characteristics, and actual
populations near the facilities in the initial screening assessment.
To address high end risk, plausible ranges of values for key
exposure and model variables were modeled via Monte Carlo procedures to
estimate the range of possible risk values and their probability of
occurring. The variables considered for the Monte Carlo modeling were
identified by sensitivity analyses. The variables were exposure
duration, beef and dairy consumption, beef and dairy biotransfer
factors, air to plant transfer, dry sludge throughput, adult inhalation
rate, and fraction of time an adult is indoors and outdoors.
The large number of exposure values used in the risk assessment are
shown in Appendix B of the TSD for incineration (USEPA, 1999c). The
following is a summary of a few key values:
Adult body weight of 71.8 kilograms (kg)
Body weight of a 3-5 year old is 17.5 kg
Exposure duration for farmer is 17.3 years
Exposure duration for home gardener is 12 years
Adult inhalation rate of 13.3 cubic meters each day
Child 3-5 years old inhalation rate is 8.3 cubic meters
each day
Child daily soil ingestion rate of 0.1 grams each day
Adult daily soil ingestion rate of 0.05 grams each day
Adult daily fish ingestion rate of 0.162 grams per kg.
body weight per day
For the farmer exposure pathway, we evaluated the inhalation of
vapor and particle-bound pollutants released from the incinerator
stack(s), soil ingestion, ingestion of homegrown fruits and vegetables,
ingestion of home-produced beef and dairy products, ingestion of
drinking water from nearby surface water bodies, and ingestion of fish
at recreational fisher levels from those water bodies. The home
gardener pathway included inhalation of vapor and particle-bound
pollutants, soil ingestion, ingestion of homegrown fruits and
vegetables, and ingestion of drinking water from surface water bodies.
For infants in both pathways, breast milk ingestion from an adult's
exposure to the above pathways is included. Dermal exposure to soil and
water and consumption of other animal products were not quantified
since exposures from these pathways are expected to be significantly
less than the pathways evaluated.
3. Incineration Risk Characterization
We found that average and high-end risks were higher for the farmer
than for the home gardener. Estimated risks were higher for individuals
closer to the facility than farther away. The most significant pathway
for the farmer was ingestion of home-grown beef and dairy products and
for the home gardener ingestion of home-grown produce. For infants of
farmers, the breast milk ingestion pathway is often the most
significant. For the six facilities, at locations where farmers and
home gardeners are likely to reside, none of the estimated risk
exceeded 1 x 10-6, including the estimated risk for infants.
Based on census data, only extremely small numbers of farm families are
predicted to be exposed to risk levels near the upper end of the
predicted range.
Additionally, the concentration of dioxins in sewage sludge being
fed into sewage sludge incinerators does not influence the amounts of
dioxins being emitted from the incinerator. The key factors influencing
the amount of dioxins being emitted are the combustion conditions in
the incinerator, incinerator design, and the efficiency and operational
conditions of any air pollution control devices used on the
incinerator. The Agency's most recent publicly available Dioxin Source
Inventory associated with the Draft Dioxin Reassessment (USEPA, 1998)
estimated that total dioxins (chlorinated dioxins and chlorinated
dibenzofurans only) being emitted from all of the Nation's sewage
sludge incinerators was approximately 14.6 grams TEQ per year, a very
minor fraction of the total North American dioxin inventory. These
amounts are expected to be further reduced over the next several years
as the requirement for all sewage sludge incinerators to comply with
either 100 parts per million (ppm) total hydrocarbons (THC) or 100 ppm
carbon monoxide (CO) in their emissions is implemented.
We investigated plans for any future changes for the six multiple
hearth incinerators (MHI) used in the risk assessment to determine if
any significant reductions in emissions of dioxin and dioxin-like
compounds might be expected in the future. Three of the six
incineration facilities indicated that no changes that might reduce
emissions were planned in the foreseeable future. They are currently
meeting the total hydrocarbon emission limitation of 100 ppm.
Two of the six incineration facilities indicated replacement of the
existing multiple hearth incinerators is taking place. One of these
facilities is bringing a fluidized bed incinerator (FBI) on line in the
first quarter of 2000, which will operate as the primary incinerator.
The currently operating MHI will be shut down and will remain as a
backup incinerator, with only occasional use. Tests of FBIs has
demonstrated more complete destruction of organic compounds than in
MHI. The other facility expects to shut down its incineration operation
completely in 2001 and start drying sewage sludge instead. Drying
involves lower temperatures and no combustion of the sewage sludge, so
this facility will significantly reduce or eliminate emissions of
organic pollutants.
The largest and highest emitting of the incineration facilities
plans to start to eliminate incineration of sewage sludge in their
multiple hearth incinerators over the next four to five years. The
facility is working to evaluate a new high temperature process that
will convert sludge to a glass-like aggregate. The facility expects to
submit a permit application within three years to build
[[Page 72055]]
the first aggregate unit. If this initial unit is successful, they will
submit another permit application to build additional units to replace
the entire multiple hearth incineration facility. However, if the new
aggregate process does not prove to be feasible, then this facility
will continue to use the existing multiple hearth incinerators. The
facility may consider building FBIs to start replacing aging MHIs.
On August 4, 1999, we promulgated amendments to the incineration
subpart of the part 503 standards, 64 FR 42552. The amendments included
a provision making all sewage sludge incineration requirements self-
implementing. All incinerator owners/operators must now continuously
monitor for either THC or CO emissions and operate their incinerators
to limit either THC or CO emissions to 100 ppm or less (40 CFR
503.40(c), 503.44, 503.45(a)). We will continue to inspect the
operations and records of these incinerators to assure attainment of
THC or CO limits.
Based on the results of the risk assessment for dioxins in sewage
sludge fired in sewage sludge incinerators and the information we have
regarding actual and projected incineration of sewage sludge in sewage
sludge incinerators, we are proposing no national standard for
incineration of sewage sludge in sewage sludge incinerators. We seek
comment on this proposal.
VI. Other Options that EPA Considered
A. Numeric Standards for All Use or Disposal Practices
Under this option, we would propose comprehensive risk-based
regulations setting numeric standards for dioxins, as well as
monitoring requirements, reporting, and record keeping provisions for
all sewage sludge use or disposal practices. We are not proposing this
option for surface disposal or incineration in a sewage sludge
incinerator. As previously explained, the risk assessments for surface
disposal and incineration did not show that the risk from placing
sewage sludge on a surface disposal site or firing sewage sludge in a
sewage sludge incinerator, including the highest emitting type of
sewage sludge incinerator, posed an unreasonable risk to human health.
We invite public comment on whether EPA should establish numeric limits
for dioxins in sewage sludge for all use or disposal methods.
B. Require all Sewage Sludge to be Landfilled or Surface Impounded
Under this option, we would propose a rule under part 503 that
would require all sewage sludge to be placed in a landfill or surface
impoundment. The rule would be based on total containment of dioxins in
sewage sludge and would virtually eliminate all exposure to dioxins
from sewage sludge. The risk assessments performed did not indicate
unreasonable risk from exposure to land applied sewage sludge with
dioxins content of 300 ppt TEQ or less or from exposure to emissions
from sewage sludge incinerators with any level of dioxins in the
incinerated sewage sludge. Therefore, we are not proposing this option.
C. No Further Regulation of Sewage Sludge for Any Use or Disposal
Practice
We considered this option for land application, as well as for
surface disposal and incineration. As discussed above, the risk
assessment shows that sewage sludge with 300 ppt TEQ dioxins that is
land-applied poses a human cancer risk in excess of one in one hundred
thousand (1 x 10-5) cancer risk only for highly exposed
subpopulations using conservative assumptions. The estimated risk of
1.7 x 10-5 is approximately one-fifth of the background risk
posed by dioxins from all other sources (USEPA, 1994). However, data
from the NSSS (USEPA, 1990) show that some treatment works produced
sewage sludge containing dioxin/dibenzofurans (not including coplanar
PCBs) as high as 1700 ppt TEQ. Although we have not done a detailed
risk assessment of the potential impacts of this highest concentration,
we believe that the incremental cancer risk would likely be on the
order of one in ten thousand (1 x 10-4) for highly exposed
subpopulations using conservative assumptions. This level of risk would
be within the Agency's acceptable range of 1 x 10-6 to
1 x 10-4. Nevertheless, we believe the better course of
action is to propose a numeric limit for dioxins in sewage sludge that
is applied to the land at a level which limits the incremental risk to
approximately 1 x 10-5 to 2 x 10-5. This approach
limits incremental risks for dioxins to levels well below background,
because of concern with multiple sources and possible cumulative
exposures. The Agency recognizes that its use of ``highly exposed
individuals'' and other conservative assumptions also builds in some
margin of safety. Therefore, we request comment on taking no action
with respect to regulating dioxins for land application of sewage
sludge.
VII. Request for Public Comments
While we are requesting comments on all aspects of this proposed
rule, we hope that public comments will also focus specifically on the
following aspects of this proposal:
(1) Establishing of a cap of 300 ppt TEQ dioxins for land applied
sewage sludge that will protect a highly exposed individual from an
incremental cancer risk of not greater than
1.7 x 10-5 (IV.B.1).
(2) Using EPA Analytical Method 1613B for the chlorinated dioxin
and dibenzofuran congeners and EPA Analytical Method 1668 or 1668A for
co-planar PCB congeners (IV.B.3).
(3) Requiring two consecutive years of monitoring results under 30
ppt TEQ before allowing a reduced monitoring schedule (IV.B.4).
(4) Our assumption that the level of dioxins in sewage sludge is
relatively constant over time and may possibly be decreasing (IV.B.4).
(5) Whether we have clarified existing monitoring requirements by
separating Sec. 503.16(a) into two paragraphs or if our proposed change
unintentionally changes the substance of the frequency of monitoring
provisions currently in Sec. 503.16(a)(1) (IV.B.4).
(6) Requesting information on the dioxin content, annual
application rates, numbers and sizes of sites, and applications per
site for sewage sludge from treatment works with a flow rate of one MGD
or less and whether to exempt small treatment works from both the
initial monitoring requirements and the dioxin limit for land
application.
(7) Our proposed designation of small treatment works as one with a
flow rate of one MGD or less, and our proposed designation of other
small sludge preparers that are not treatment works as those preparing
sewage sludge for land application in an amount of 290 dry metric tons
or less annually (IV.B.5).
(8) Requesting information on exposure pathways not evaluated,
including direct risks to livestock, soil organisms, wildlife, and
plants, resulting from dioxins in sewage sludge that is land applied or
incinerated (V.B.1, V.D.1).
(9) Proposing no action in regulating dioxins in sewage sludge that
is placed in a surface disposal unit or incinerated in a sewage sludge
incinerator (V.C.3, V.D.3).
(10) Whether EPA should establish numeric limits for dioxins in
sewage sludge for all use or disposal methods (VI.A).
(11) Proposing no action for dioxins in sewage sludge that is land-
applied (VI.C).
(12) Whether there are any privately-owned treatment works with
flows greater than one MGD that also have revenues less than $6
million. If such facilities are operating, we request information on
flow, revenues, and sludge disposal methods (VIII.B).
(13) Data on the cost to switch from land application to
alternative use or disposal practices (compared to our assumption of
$189 per dry metric ton
[[Page 72056]]
to switch to co-disposal with municipal solid waste) (VIII.B).
(14) Potential impacts of the proposed rule on small entities and
on issue related to such impacts (VIII.B).
(15) The use of the proposed alternative definition of small
entity--both for this proposed rule and for subsequent rulemakings
(VIII.B).
(16) Consensus methods that are suitable for compliance monitoring
for determining concentrations of dioxins, furans, and coplanar PCBs in
sewage sludge (VIII.H).
VIII. Regulatory Assessment Requirements
A. Executive Order 12866, Regulatory Planning and Review
Under Executive Order 12866, [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 government 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.
It has been determined that this rule is not a ``significant
regulatory action'' under the terms of Executive Order 12866 and is
therefore not subject to OMB review.
B. Regulatory Flexibility Act (RFA), as Amended by the Small Business
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et
seq.
The RFA generally requires an agency to prepare a regulatory
flexibility analysis of any rule subject to notice and comment
rulemaking requirements under the Administrative Procedure Act or any
other statute, unless the agency certifies that the rule will not have
a significant economic impact on a substantial number of small
entities. Small entities include small businesses, small organizations,
and small governmental jurisdictions.
Today's proposal affects two categories of entities: (1) publicly-
owned treatment works (POTWs) owned by local governmental
jurisdictions, and (2) privately-owned treatment works and sludge-only
preparers, which are businesses. For this proposal, EPA first assessed
the effects on small entities using the small entity definition for
each category as defined in the RFA. EPA also assessed the effects of
the proposal using the alternative definition for each category of
small entity that EPA is proposing to establish for this rule. (See the
discussion under ``Use of Alternative Definition'' later in this
section.)
For purposes of assessing the impact of today's proposal on small
entities, small entities are defined as (1) a small business that meets
RFA default definitions based on SBA size standards found in 13 CFR
121.201 (i.e., small refuse systems that have less than $6 million in
annual revenues); (2) a small governmental jurisdiction that is a
government of a city, county, town, school district, or special
district with a population of less than 50,000; and (3) a small
organization that is any not-for-profit enterprise which is
independently owned and operated and is not dominant in its field.
To evaluate the economic impact on small governmental jurisdictions
subject to today's rule, EPA looked at the effect on municipalities
owning a POTW that services a population of 50,000 or fewer with
complete jurisdiction over all indirect discharges to and discharges
from a treatment works. EPA considers this an appropriate surrogate for
small governmental jurisdictions. (EPA recognizes that, to the extent a
governmental jurisdiction may own more than one POTW serving a
population of 50,000, this evaluation may overstate the number of small
governmental jurisdictions.)
Based upon average domestic sewage loadings, a POTW serving a
population of 50,000 or fewer would correspond to one processing
approximately five million gallons per day (five MGD) of wastewater.
EPA's data, however, do not permit it to accurately estimate the number
of POTWs in a one to five MGD range because EPA collected information
for the flow range of one MGD to ten MGD. Therefore, in order to
determine the impact on small governmental jurisdictions, EPA first
looked at the economic impact of today's proposal on those POTWs with
one to ten MGD flows who land apply their sewage sludge because the
proposed dioxin limit would apply only to those POTWs that land apply
their sewage sludge. EPA estimates that there are approximately 890
POTWs in the one to ten MGD flow range who land applied their sewage
sludge. EPA estimated costs for these facilities to comply with the
proposed monitoring requirements, as described in Section IV.D. EPA
estimates annual monitoring costs of $2,000 to test for the parameters
included in today's proposal. The frequency of this monitoring varies,
depending on the outcome of the test, as explained in Section IV.B.4.
EPA also estimated incremental disposal costs for between 40 and 50
facilities in the one to ten MGD flow range with sewage sludge that
might exceed the proposed 300 ppt TEQ numeric limit for dioxins in
sewage sludge. EPA estimates that the costs of the proposal would not
exceed $6 million for the group of POTWs in the one to ten MGD flow
range.
For purposes of evaluating the economic impact of this rule on
small governmental jurisdictions, EPA compared costs with average
annual revenues for small governmental jurisdictions obtained from the
1992 Census of Governments. The Census data are reported at a level of
detail that allow EPA to focus on the small governmental jurisdictions,
as defined in the RFA. The data further allow EPA to limit the revenue
information to populations between 10,000 and 50,000, which correspond
to the small POTWs covered by the proposed rule. (POTWs with flows at
or below one MGD are exempt from this rule.) The revenues for the
governmental jurisdictions in the 10,000 to 50,000 population group are
approximately $57 billion. The costs of the proposed rule represent
less than 0.01 percent of the entities' revenues. In other words, when
EPA divided the total compliance costs for the group of POTWs (i.e.,
costs of $6 million) by the revenues for the group of small
governmental jurisdictions (i.e., revenues of $57 billion), those costs
are only one, one-hundredth of the revenues. EPA concludes that the
rule will not have a significant impact on a substantial number of
small governmental jurisdictions owning these POTWs.
For privately-owned treatment works, the RFA definition of small
entity is a small business as defined in U.S. Small Business
Administration (SBA) regulations at 13 CFR 121.201. Those regulations
define small refuse systems (Standard Industrial Classification 4953)
as having less than $6 million in annual revenues. In the Regulatory
Impact Analysis for the previous Part 503 regulations (EPA 821-R-93-
006, March 1993), EPA concluded that the universe of privately-owned
treatment works is limited to facilities with wastewater
[[Page 72057]]
flows below one MGD. Today's proposed regulation excludes treatment
works with flows at or below one MGD; thus, EPA concludes that the
proposed rule imposes no requirements on small, privately-owned
treatment works. Although EPA estimates that a privately-owned
treatment works with annual revenues near $6 million (if one exists)
corresponds to flows much greater than one MGD, EPA has not identified
any such treatment works. Theoretically, any privately-owned treatment
works with flows greater than one MGD and also having revenues less
than $6 million would be small entities, as defined by the RFA. EPA
solicits comment on whether such treatment works are operating, and if
so, requests information on flow, revenues, and sludge disposal
methods.
For sludge-only preparers, under the RFA definition cited above, a
small entity is a preparer with annual revenues of less than $6
million. EPA data suggest that there are substantially fewer than 100
sludge-only preparers that are small entities. EPA first considered the
potential impacts to a subset of small preparers--those with annual
revenues less than $80,000, which corresponds to production of
approximately 290 dry metric tons of sewage sludge. EPA equates a
production level of 290 dry metric tons of sewage sludge to a
wastewater flow of one MGD. Today's proposed rule excludes this subset
of very small sludge-only preparers (see section IV.B.5.). Thus, this
analysis suggests for sludge-only preparers with annual revenues less
than $80,000, today's proposed rule imposes no requirements. For the
remaining sludge-only preparers that are also small businesses (by RFA
definition), i.e., those with annual revenues between $80,000 and $6
million, EPA estimated the potential impacts as additional monitoring
costs (see section IV.D.). For the small preparers with revenues
between $80,000 and $6 million, the estimated impacts will range from
0.03 to 2.5 percent of revenues. Thus, EPA estimates that there is not
a significant economic impact on a substantial number of small sludge-
only preparers.
After considering the economic impacts of today's proposed rule on
small entities, I certify that this action will not have a significant
economic impacts on a substantial number of small entities. EPA
nonetheless has tried to reduce the impacts of this rule on small
entities. For example, the proposed rule imposes no requirements on
treatment works (public or private) with flows less than or equal to
one MGD. This regulatory exclusion markedly limits the number of
treatment works with monitoring requirements. These smallest POTWs and
privately-owned treatment works will face no changes in their sludge
disposal operations. We continue to be interested in the potential
impacts of the proposed rule on small entities and welcome comments on
issues related to such impacts.
Use of Alternative Definition. As noted, EPA is certifying that the
proposed rule will not have a significant economic impact on a
substantial number of small entities, using the RFA definitions for
small entities. However, the RFA authorizes an agency to use
alternative definitions for each category of small entity, ``which are
appropriate to the activities of the agency'' after proposing the
alternative definition(s) in the Federal Register and taking comment. 5
U.S.C. 601(3)-(5). In addition, to establish an alternative definition
for small business, agencies must consult with SBA's Chief Counsel for
Advocacy.
In today's rule, EPA is proposing to define ``small entity'' for
purposes of its regulatory flexibility assessments under the RFA as
follows: EPA is proposing to define ``small governmental jurisdiction''
as any municipality or special district operating a POTW with a
capacity of one MGD or less. Generally flows in this size range
correspond to service populations of 10,000 or less. EPA also is
proposing to define ``small business'' as a privately-owned treatment
works with a capacity of one MGD or less and sludge-sonly preparers
with finished product amounts of 290 dry metric tons or less of sewage
sludge. EPA will initiate consultation with the SBA on the alternative
definition for ``small business'' shortly.
EPA is proposing these alternative definitions for the purpose of
consistency within the sewage sludge use or disposal program. When EPA
published the Standards for the Use and Disposal of Sewage Sludge in
1993, the Agency used the one MGD definition for its regulatory
flexibility assessment. At that time (and in the 1990 Notice of Data
Availability, 55 FR 47210 (Nov. 9, 1990) (USEPA, 1990)), EPA noted the
well-accepted and frequent use of this definition for small POTWs. The
existing part 503 land application rule differentiates between
treatment works with flow rates of one MGD or less and larger treatment
works. Treatment works with flow rates of one MGD or less are required
to monitor less frequently and they are excluded from reporting
requirements.
In addition to proposing to establish these alternative definitions
for this rule, EPA also is proposing to establish and use these
alternative definitions of ``small entity'' for purposes of its
regulatory flexibility assessments under the RFA for any subsequent
rulemakings pursuant to section 405 of the Clean Water Act, 33 U.S.C.
1345 and amendments to 40 CFR 503.
The Agency is interested in receiving comments on the use of this
alternative definition of small entity--both for this proposed rule and
for subsequent rulemakings.
If EPA had used the alternative definitions in its RFA assessment
of the impact of today's proposed rule on small entities that would be
subject to the requirements of the rule, the analysis would have
supported the same conclusions; i.e., EPA would certify that there is
no significant economic impact on a substantial number of small
entities. The proposed rule would not impose any requirements on POTWs
and privately-owned treatment works with wastewater flows at or below
one MGD. Consequently, the proposed rule would not have any economic
impact on small governmental jurisdictions and small businesses that
are treatment works under the alternative definitions. Similarly, for
sludge-only preparers, with a small entity definition based on 290 dry
metric tons of sewage sludge, the proposed rule would not have any
economic impact on small businesses that are sludge preparers.
C. Paperwork Reduction Act
The Office of Management and Budget (OMB) approved the information
collection requirements for existing 40 CFR part 503 under the
Paperwork Reduction Act, 44 U.S.C. 3501 et seq. (PRA) and assigned OMB
Control No. 2040-0004.
The information collection requirements in this proposed rule have
been submitted for approval to OMB under the PRA. An Information
Collection Request (ICR) document has been prepared by EPA (ICR No.
0229.14) and a copy may be obtained from Sandy Farmer by mail at OP
Collection Strategies Division; U.S. Environmental Protection Agency
(2822); 401 M St., SW., Washington, DC 20460, by e-mail at
farmer.sandy@epamail.epa.gov, or by calling (202) 260-2740. For
technical information contact Arleen Plunkett by calling (202) 260-
3418. A copy may also be downloaded off the internet at
http://www.epa.gov/icr.
This proposed rule will require certain sewage treatment plants
which produce sewage sludge that is applied to the land and other
preparers of sewage sludge for application to the land to monitor their
sewage sludge for dioxins
[[Page 72058]]
and keep records of the analytical results. Entities which monitor for
dioxin in their sewage sludge will be required to submit these records
to the permitting authority. This information is needed by the
permitting authority to ensure compliance with the proposed numerical
standard for dioxins, thereby assuring that the acceptable incremental
risk to the highly exposed individual from exposure to dioxins from
land application of sewage sludge is not exceeded. The responses to the
collection of information will be mandatory pursuant to section 405(d)
of the CWA, 33 U.S.C. 1345(d).
The Agency has estimated the total respondent burden hours and
costs for these requirements of the proposed rule. 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.
The Agency estimates that each respondent, when required to monitor
for dioxins, will expend a total of one hour to sample their sewage
sludge, submit this sample to a laboratory for dioxins analysis,
receive the analytical result from the laboratory, record the result,
and for certain size entities, report this result to the permitting
authority. EPA estimates that in the first year that this rule is in
effect, 1154 facilities will perform dioxin monitoring. The total
national burden is, therefore, estimated to be 1154 hours. During the
second year that this rule is in effect, 1096 facilities will be
performing monitoring for a total burden of 1096 hours. From the third
year on, the Agency estimates that annually 754 facilities will be
monitoring for dioxins for a total burden of 754 hours per year.
Analytical costs per sample are estimated to be $2,000. Therefore
in year one, total analytical costs to the 1154 respondents are
estimated to be $2,308,000. Total analytical costs for the 1096
respondents in year two are estimated to be $2,192,000. Total
analytical costs for the 754 respondents in year three and beyond are
estimated to be $1,508,000 annually.
For the permitting authorities, whether they are the EPA Regional
Offices or the three States that have received authority to administer
the part 503 regulatory program (i.e., Utah, Oklahoma, and Texas), the
Agency estimates that each will be required to spend one hour to review
the analytical information submitted by the respondents. Therefore, the
three States identified above and the 10 EPA Regions will expend a
total of 13 hours annually due to these dioxin monitoring,
recordkeeping, and reporting requirements.
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.
D. Unfunded Mandate Reform Act
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 section 202 of the UMRA, 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 EPA can promulgate a 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 other
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 of 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 notifying
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.
EPA has determined that today's proposed rule does not contain 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. The highest estimated total costs in
any one year (1998 dollars) of today's proposed rule are $18 million.
Thus, today's proposed rule is not subject to the requirements of
sections 202 and 205 of the UMRA.
As indicated in the Regulatory Flexibility Act discussion (see
section VIII. B.), we have determined that this rule will not have a
significant impact on a substantial number of small governments.
Additionally, this rule will not uniquely impact small governments
because it applies to both large and small entities. Today's proposed
rule exempts wastewater treatment works with flows of less than one MGD
from the provisions of this proposed rule including monitoring
requirements. This exemption for these low flow wastewater treatment
works, therefore, will not create any costs for the small size
municipalities or small private sector firms that own and operate these
facilities. Thus, today's proposed rule is not subject to the
requirements of section 203 of UMRA.
E. Executive Order 13132, Federalism
Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
Under section 6 of Executive Order 13132, EPA may not issue a
regulation that has federalism implications, that imposes substantial
direct compliance costs, and that is not required by statute, unless
the Federal government provides the funds necessary to pay the direct
compliance costs incurred by State and local governments, or EPA
consults with State and local officials early in the
[[Page 72059]]
process of developing the proposed regulation. EPA also may not issue a
regulation that has federalism implications and that preempts State law
unless the Agency consults with State and local officials early in the
process of developing the proposed regulation.
Section 4 of the Executive Order contains additional requirements
for rules that preempt State or local law, even if those rules do not
have federalism implications (i.e., the rules will not have substantial
direct effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government). Those
requirements include providing all affected State and local officials
notice and an opportunity for appropriate participation in the
development of the regulation. If the preemption is not based on
express or implied statutory authority, EPA also must consult, to the
extent practicable, with appropriate State and local officials
regarding the conflict between State law and Federally protected
interests within the agency's area of regulatory responsibility.
This proposed rule does not have federalism implications. It will
not have substantial direct effects on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government,
as specified in Executive Order 13132. This proposal would add a
regulated pollutant to one part of the existing regulatory program,
however it would not change the existing relationship between federal,
State, and local officials. Thus, the requirements of section 6 of the
Executive Order do not apply to this proposed rule.
This proposed rule will preempt State and or local law that is less
stringent or inconsistent with these provisions, consistent with CWA
section 510, 33 U.S.C. 1370. By publishing and inviting comment on this
proposed rule, EPA hereby is providing State and local officials notice
and an opportunity for appropriate participation. Thus, EPA has
complied with the requirements of section 4 of the Executive Order.
F. Executive Order 13084, Consultation and Coordination With Indian
Tribal Governments
Under Executive Order 13084, 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
governments 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, Executive Order 13084
requires EPA to provide to 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, Executive Order 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.''
Today's proposed rule does not significantly or uniquely affect the
community of Indian tribal governments nor does it impose substantial
direct compliance costs on them. As indicated in the Regulatory
Flexibility Act discussion (see section VIII. B.), we have determined
that this rule will not have a significant impact on a substantial
number of small governments. The impact on Tribal governments would
similar to that on small governments. We, therefore, don't expect this
rule to have a significant impact on tribal governments. Neither do we
expect this rule will impose substantial direct compliance costs on
them. Additionally, this rule will not uniquely impact the communities
of Indian tribal governments because it applies to all entities which
land apply sewage sludge. Today's proposed rule exempts small
wastewater treatment works with flows of less than one MGD from the
provisions of this proposed rule including monitoring requirements.
This exemption for these low flow wastewater treatment works,
therefore, will not create any costs for the small size tribal
governments that own and operate these facilities. Accordingly, the
requirements of section 3(b) of Executive Order 13084 do not apply to
this rule.
G. Executive Order 13045, Protection of Children From Environmental
Health Risks and Safety Risks
Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any
rule that: (1) Is determined to be ``economically significant'' as
defined under Executive Order 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 it
is not ``economically significant'' as defined in Executive Order
12866, and because the Agency does not have reason to believe the
environmental health and safety risks addressed by this action present
a disproportionate risk to children. Nevertheless, under EPA policy
(EPA Policy on Evaluating Health Risks to Children), the risk
assessment for this rule has addressed potential risk to breast-feeding
infants and toddlers and the effects of exposure to dioxins. Two
pathways of exposure are most important in addressing the risk
potential for children. In the pathway which assumes incidental
ingestion, we assumed that the toddler from ages one to six eats 0.4
gram of soil mixed with sewage sludge every day for five years. In the
breast-feeding infant pathway, the hypothetical highly exposed
individual is the nursing infant (the nursing period is six months) of
the rural family mother who eats, on a yearly basis, 10% of her beef,
10% of her beef liver, 10% of her lamb and 3% of her dairy products
from animals raised on the farm and fed forage grown on sewage sludge-
amended soils. Moreover, the animals are exposed through ingestion of
sewage sludge and soils through grazing on pasture. The breast-feeding
infant pathway was one of the pathways used for setting the proposed
numeric limit.
Our assessment of these pathways does not reveal a disproportionate
environmental health or safety risks to children. Incremental dioxins
exposure and subsequent cancer risks from sewage sludge use or disposal
practices are within the risks that would normally be expected and
within EPA's range of acceptable risk.
The public is invited to submit or identify peer-reviewed studies
and data, of which the Agency may not be aware, that assessed results
of early life exposure to dioxins.
H. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272
note) directs EPA to use voluntary consensus
[[Page 72060]]
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 the
Office of Management and Budget (OMB), explanations when the Agency
decides not to use available and applicable voluntary consensus
standards. This proposed rule involves technical standards. Therefore,
the Agency conducted a search to identify potentially applicable
voluntary consensus standards. However, we identified no consensus
methods for determination of dioxins, furans or PCBs in solid matrices
such as sewage sludge. Therefore, EPA proposes to use Method 1613B and
Method 1668. EPA welcomes comments on this aspect of the proposed
rulemaking and, specifically, invites the public to identify
potentially applicable voluntary consensus standards for determination
of dioxins in sewage sludge and to explain why such standards should be
used in this regulation.
IX. List of References
Green, et al. 1995. Comments on Estimating Exposure to Dioxin-Like
Compounds: Review Draft and Addendum.
US Conference of Mayors 1999. The United States Conference of
Mayors/ Urban Water Council Biosolids Land Application-The Dioxin
Situation.
USEPA 1989. Interim Procedures for Estimating Risks Associated with
Exposure to Mixtures of Chlorinated Dibenzo-p-dioxins and -
dibenzofurans (CDDs and CDFs) and 1989 Update. Washington, DC Risk
Assessment Forum. EPA/625/3-89.016.
USEPA 1990. National Sewage Sludge Survey; Availability of
Information and Data, and Anticipated Impacts on Proposed
Regulations; Proposed Rule. Federal Register 55 (218): 47210-47283.
USEPA 1994. Health Assessment for 2,3,7,8-TCDD and Related
Compounds. External Review Draft. EPA/600/BP-92/001a-c, and,
Estimating Exposure to Dioxin-Like Compounds. Volume I. Executive
Summary. Volume II. Properties, Sources, Occurrence, and Background
Exposures.
Volume III. Site-Specific Assessment Procedures. External Review
Draft. EPA/600/6-88/005Ca-c. National Center for Environmental
Assessment. Washington, DC.
USEPA 1995. Policy for Risk Characterization. Memorandum of Carol M.
Browner, Administrator, March 21, 1995, Washington, DC.
USEPA 1996. Technical Support Document for the Round Two Sewage
Sludge Pollutants. Office of Science and Technology. Washington, DC.
EPA-822-R-96-003.
USEPA 1997. Exposure Factors Handbook. National Center for
Environmental Assessment. Washington, DC. EPA/600/P-95/002F(a-c).
USEPA 1998. The Inventory of Sources of Dioxin in the United States.
National Center for Environmental Assessment. External Review Draft.
Washington, DC. EPA/600/P-98/002Aa.
USEPA 1999a. Incremental Costs Associated with Regulating Dioxins
and PCBs in Biosolids. Office of Science and Technology. Washington,
DC.
USEPA 1999b. Risk Analysis for the Round Two Biosolids Pollutants.
Office of Science and Technology. Washington, DC.
USEPA 1999c. Sewage Sludge Incinerators' Dioxin-Like Compound Risk
Analysis-Draft Technical Documentation. Office of Air Quality
Planning and Standards. Research Triangle Park, N.C.
USEPA 1999d. Sewage Sludge Incinerators' Dioxin-Like Compound Risk
Analysis-Draft Addendum with PCB Emissions. Office of Air Quality
Planning and Standards. Research Triangle Park, N.C.
USEPA 1999e. Pollutant Concentration Percentile Estimates to Support
Phase II Regulations for Biosolids Use or Disposal. Office of
Science and Technology. Washington, D.C.
Van den Berg M, et al. 1998. Toxic Equivalent Factors (TEFs) for
PCBs, PCDDs, and PCDFs for Humans and Wildlife. Environ. Health
Perspect. 106, 775-792.
List of Subjects in 40 CFR Part 503
Environmental protection, Frequency of monitoring, Incineration,
Intergovernmental relations, Land application, Management practices,
Pathogens, Pollutants, Reporting and recordkeeping requirements,
Surface disposal, Vector attraction reduction.
Dated: December 15, 1999.
Carol M. Browner,
Administrator.
For the reasons set out in the preamble, title 40, chapter I of the
Code of Federal Regulations is proposed to be amended as follows:
PART 503--STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE
1. The authority citation for part 503 continues to read as
follows:
Authority: Sections 405(d) and (e) of the Clean Water Act, as
amended by Pub. L. 95-217, Sec 54(d), 91 Stat. 1591 (33 U.S.C.
1345(d) and (e)); and Pub. L. 100-4 Title IV, Sec. 406(a), (b), 101
Stat., 71, 72 ( 33 U.S.C. 1251 et seq.).
2. Add new paragraph (b)(8) to Sec. 503.8 as follows:
Sec. 503.8 Sampling and analysis.
* * * * *
(b) * * *
(8) Dioxins. EPA Method No. 1613B for the seven dioxin and ten
dibenzo- furan congeners. EPA Method No.1668 for the 12 coplanar
polychlorinated biphenyl congeners. You can purchase a copy of EPA
Method No. 1613B from the National Technical Information Service (NTIS)
by requesting NTIS publication number NTIS#: PB93-236024 at 1-800-553-
NTIS (or online at http://www.ntis.gov/). You can also obtain this
document through the Educational Resources Information Center by
requesting ERIC publication number W-105 at 1-800-443-ERIC (or online
at http://www.accesseric.org/). EPA Method Number 1668 (EPA No.821/C-
97-005821/C-97-005) is available on the Office of Water Methods and
Guidance Diskette 2#. You can request a copy from the EPA Office of
Water Resource Center at (202) 260-7786 or by sending an e-mail to:
center.water-resource@epa.gov.
3. Redesignate paragraphs (f) through (bb) as (g) through (cc) in
and add a new paragraph (f) as follows:
Sec. 503.9 General definitions.
* * * * *
(f) Dioxins means all of the seven 2,3,7,8 chlorinated dibenzo-p-
dioxin congeners, ten 2,3,7,8 chlorinated dibenzofuran congeners, and
12 coplanar polychlorinated biphenyl congeners as follows:
------------------------------------------------------------------------
CAS No. Congener
------------------------------------------------------------------------
1746-01-6............................. 2,3,7,8-Tetrachlorodibenzo-p-
dioxin
40321-76-4............................ 1,2,3,7,8-Pentachlorodibenzo-p-
dioxin
39227-28-6............................ 1,2,3,4,7,8-Hexachlorodibenzo-p-
dioxin
57653-85-7............................ 1,2,3,6,7,8-Hexachlorodibenzo-p-
dioxin
19408-74-3............................ 1,2,3,7,8,9-Hexachlorodibenzo-p-
dioxin
35822-46-9............................ 1,2,3,4,6,7,8-Heptachlorodibenzo-
p-dioxin
3268-87-9............................. 1,2,3,4,6,7,8,9-
Octachlorodibenzo-p-dioxin
[[Page 72061]]
51207-31-9............................ 2,3,7,8-Tetrachlorodibenzofuran
57117-41-6............................ 1,2,3,7,8-
Pentachlorodibenzofuran
57117-31-4............................ 2,3,4,7,8-
Pentachlorodibenzofuran
70648-26-9............................ 1,2,3,4,7,8-
Hexachlorodibenzofuran
57117-44-9............................ 1,2,3,6,7,8-
Hexachlorodibenzofuran
72918'21-9............................ 1,2,3,7,8,9-
Hexachlorodibenzofuran
60851-34-5............................ 2,3,4,6,7,8-
Hexachlorodibenzofuran
67562-39-4............................ 1,2,3,4,6,7,8-
Heptachlorodibenzofuran
55673-89-7............................ 1,2,3,4,7,8,9-
Heptachlorodibenzofuran
39001-02-0............................ 1,2,3,4,6,7,8,9-
Octachlorodibenzofuran
32598-13-3............................ 3,3',4,4'-Tetrachlorobiphenyl
70362-50-4............................ 3,4,4',5-Tetrachlorobiphenyl
57465-28-8............................ 3,3',4,4',5-Pentachlorobiphenyl
32598-14-4............................ 2,3,3',4,4'-Pentachlorobiphenyl
31508-00-6............................ 2,3',4,4',5-Pentachlorobiphenyl
65510-44-3............................ 2',3,4,4',5-Pentachlorobiphenyl
74472-37-0............................ 2,3,4,4',5-Pentachlorobiphenyl
32774-16-6............................ 3,3',4,4',5,5'-
Hexachlorobiphenyl
38380-08-4............................ 2,3,3',4,4',5-Hexachlorobiphenyl
69782-90-7............................ 2,3,3',4,4',5'-
Hexachlorobiphenyl
52663-72-6............................ 2,3',4,4',5,5'-
Hexachlorobiphenyl
39635-31-9............................ 2,3,3',4,4',5,5'-
Heptachlorobiphenyl
------------------------------------------------------------------------
* * * * *
4. Amend Sec. 503.10 by redesignating paragraph (a) as (a)(1) and
adding a title to paragraph (a) before (a) (1); and adding paragraph
(a)(2) as follows:
Sec. 503.10 Applicability.
(a) General applicability of Subpart B--Land Application.
* * * * *
(2) The pollutant limits in Sec. 503.13(a)(1), (a)(2)(ii), (a)(3),
and (a)(4)(i) do not apply to sewage sludge prepared by, and the
monitoring requirements in Sec. 503.16(a)(3) do not apply to:
(i) A treatment works that treats domestic sewage with a flow rate
equal to or less than one million gallons per day or;
(ii) A person who prepares sewage sludge or who derives a material
from sewage sludge in an amount equal to or less than 290 dry metric
tons per year.
* * * * *
Sec. 503.13 [Amended]
5. Amend Sec. 503.13 by adding a sentence after the header to
paragraph (a) and adding an entry for ``Dioxins'' in alphabetical order
in paragraph (b)(1) and adding an entry for ``Dioxins'' in alphabetical
order in paragraph (b)(3) as follows:
Sec. 503.13 Pollutant limits.
(a) Sewage sludge. Except as provided in Sec. 503.10(a)(2), the
following pollutant limits apply to sewage sludge that is applied to
the land.
* * * * *
(b) * * *
(1) * * *
Table 1 of Sec. 503.13--Ceiling Concentrations
------------------------------------------------------------------------
Ceiling concentration
Pollutant (milligrams per
kilogram) \1\
------------------------------------------------------------------------
* * * * *
Dioxins (defined in Sec. 503.9(f)........... 0.003 TEQ
* * * * *
------------------------------------------------------------------------
\1\ Dry weight basis.
* * * * *
(3) * * *
Table 3 of Sec. 503.13--Pollutant Concentrations
------------------------------------------------------------------------
Monthly average
Pollutant concentration (milligrams
per kilogram) \1\
------------------------------------------------------------------------
* * * * *
Dioxins (defined in Sec. 503.9(f)).......... 0.0003 TEQ
* * * * *
------------------------------------------------------------------------
\1\ 1 Dry weight basis.
[[Page 72062]]
* * * * *
6. Revise (a) of Sec. 503.16 as follows:
Sec. 503.16 Frequency of monitoring.
(a) Sewage sludge. You must monitor for pollutants in sewage
sludge, pathogen density and vector attraction reduction according to
the following schedule:
(1) For all pollutants except dioxins listed in Sec. 503.13(b)(1)
Table 1 and (b)(3) Table 3 and all pollutants listed in
Sec. 503.13(b)(2) Table 2 and (b)(4) Table 4, you must monitor as
provided in Table 1 of this section.
(2) For pathogen density requirements in Sec. 503.32(b)(2) through
(b)(4) and the vector attraction reduction requirements in
Sec. 503.33(b)(1) through (b)(8), you must monitor as provided in Table
1 of this section.
Table 1 of Sec. 503.16
------------------------------------------------------------------------
Amount of sewage sludge \1\ (metric
tons per 365 day period) Frequency
------------------------------------------------------------------------
Greater than zero but less than 290.... Once per year.
Equal to or greater than 290 but less Once per quarter (four times
than 1,500. per year).
Equal to or greater than 1,500 but less Once per 60 days (six times per
than 15,000. year).
Equal to or greater than 15,000........ Once per month (12 times per
year).
------------------------------------------------------------------------
\1\ Either the amount of bulk sewage sludge applied to the land (dry
weight basis), or the amount of sewage sludge or material derived from
sewage sludge sold or given away in a bag or other container prepared
by a person who prepares sewage sludge for application to the land
(dry weight basis).
(3) Except as provided in Sec. 503.10(a)(2), for dioxins listed in
Sec. 503.13(b)(1) and (3), you must monitor your sewage sludge
annually, as of [one year after effective date of final rule].
(i) If the level of dioxins in your sewage sludge is above 30 ppt
TEQ but below 300 ppt TEQ, then you must monitor for dioxins annually.
(ii) If the level of dioxins in your sewage sludge is at or below
30 ppt TEQ for any two consecutive years, then you may reduce the
frequency of monitoring to once every five years.
(iii) If you have reduced the frequency of monitoring under
paragraph (a)(3)(ii) of this section and the level of dioxins in your
sewage sludge exceeds 30 ppt TEQ, you must resume monitoring your
sewage sludge annually.
(4) After the sewage sludge has been monitored for two years at the
frequency in Table 1 of this section, the permitting authority may
reduce the frequency of monitoring for the pollutant concentrations and
for the pathogen density requirements in Sec. 503.32(a)(5)(ii) and
(a)(5)(iii).
* * * * *
[FR Doc. 99-33033 Filed 12-22-99; 8:45 am]
BILLING CODE 6560-50-U
