[Federal Register Volume 59, Number 145 (Friday, July 29, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17650]
[[Page Unknown]]
[Federal Register: July 29, 1994]
_______________________________________________________________________
Part III
Environmental Protection Agency
_______________________________________________________________________
40 CFR Parts 141 and 142
National Primary Drinking Water Regulations: Enhanced Surface Water
Treatment Requirements; Proposed Rule
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 141 and 142
[WH-FRL-4998-1]
National Primary Drinking Water Regulations: Enhanced Surface
Water Treatment Requirements
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: EPA is proposing to amend the Surface Water Treatment Rule to
provide additional protection against disease-causing organisms
(pathogens) in drinking water. This action would primarily focus on
treatment requirements for the waterborne pathogens Giardia,
Cryptosporidium, and viruses. With the exception of one requirement
(sanitary surveys), this action would apply to all public water systems
that use surface water or ground water under the influence of surface
water, and serve 10,000 people or more. Among the features of the rule
would be a stricter watershed control requirement for systems using
surface water that wish to avoid filtration; a change in the definition
of ground water under the influence of surface water to include the
presence of Cryptosporidium; a periodic sanitary survey requirement for
all systems using surface water or ground water under the influence of
surface water, including those that serve fewer than 10,000 people; a
health goal (maximum contaminant level goal) of zero for
Cryptosporidium; and several alternative requirements for augmenting
treatment control of Giardia, Cryptosporidium, and viruses.
DATES: Comments should be postmarked or delivered by hand on or before
May 30, 1996. Comments received after this date may not be considered.
Public hearings will be held at the addresses indicated below under
ADDRESSES on August 30, 1996 (and 31, if necessary) in Denver, CO and
on September 13, 1994 (and 14, if necessary) in Washington, DC.
ADDRESSES: Send written comments to ESWTR Docket Clerk, Water Docket
(MC-4101); U.S. Environmental Protection Agency; 401 M Street, SW;
Washington, DC 20460. Please submit any references cited in your
comments. EPA would appreciate an original and three copies of your
comments and enclosures (including references). Commenters who want EPA
to acknowledge receipt of their comments should include a self-
addressed, stamped envelope. No facsimiles (faxes) will be accepted
because EPA cannot ensure that they will be submitted to the Water
Docket. The Agency requests commenters to follow the instructions
regarding format provided in Section IX of the Preamble, immediately
before the list of references.
The Agency will hold public hearings on the proposal at two
different locations indicated below:
1. Denver Federal Center, 6th and Kipling Streets, Building 25, Lecture
Halls A and B (3d Street), Denver, CO 80225 on August 30 (and 31, if
necessary), 1994.
2. EPA Education Center Auditorium, 401 M Street SW., Washington, D.C.
20460, on September 13 (and 14, if necessary), 1994.
The hearings will begin at 1:00 p.m., with registration at 12:30
p.m., on the first day. The hearings will begin at 9:30 a.m., with
registration at 9:00 a.m., on the second day. The Hearings will end at
4:00 p.m., unless concluded earlier. Anyone planning to attend the
public hearings (especially those who plan to make statements) may
register in advance by writing the ESWTR Public Hearing Officer, Office
of Ground Water and Drinking Water (4603), USEPA, 401 M Street, S.W.,
Washington, D.C. 20460; or by calling Tina Mazzocchetti, (703) 931-
4600. Oral and written comments may be submitted at the public hearing.
Persons who wish to make oral presentations are encouraged to have
written copies (preferably three) of their complete comments for
inclusion in the official record.
The proposed rule with supporting documents and all comments
received are available for review at the Water Docket at the address
above. For access to Docket materials, call (202) 260-3027 between 9 am
and 3:30 pm for an appointment.
FOR FURTHER INFORMATION CONTACT: The Safe Drinking Water Hotline,
Telephone (800) 426-4791. The Safe Drinking Water Hotline is open
Monday through Friday, excluding Federal holidays, from 9 a.m. to 5:30
p.m. Eastern Time. For technical inquiries, contact Stig Regli or Paul
S. Berger, Ph.D., Office of Ground Water and Drinking Water (MC 4603),
U.S. Environmental Protection Agency, 401 M Street SW., Washington DC
20460; telephone (202) 260-7379 (Regli) or (202) 260-3039 (Berger); or
Bruce A. Macler, Ph.D., Water Management Division, Region 9, U.S.
Environmental Protection Agency, 75 Hawthorne Street (W-6-1), San
Francisco, CA 94105-3901; telephone (415) 744-1884.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Statutory Authority
II. Regulatory Background
III. Discussion of Proposed Rule
A. Basis for Amending Existing SWTR: Limitations of SWTR
B. General Approach for Revising SWTR
C. Proposed Maximum Contaminant Level Goal and Treatment
Technique for Cryptosporidium
D. Proposed Revisions to SWTR under All Treatment Alternatives
1. Inclusion of Cryptosporidium in definition of ``groundwater
under the direct influence of surface water''
2. Inclusion of Cryptosporidium in watershed control
requirements
3. Sanitary surveys for all surface water systems
4. Possible supplemental requirements
E. Alternative Treatment Requirements
1. Options for defining pathogen densities in source waters
2. Treatment alternatives for controlling pathogens
IV. State Implementation
A. Special State Primacy Requirements
B. State Recordkeeping Requirements
C. State Reporting Requirements
V. Public Notification Language
VI. Economic Analysis
A. Cost of Proposed Rule
B. Benefits of Proposed Rule
VII. Other Statutory Requirements
A. Executive Order 12866
B. Regulatory Flexibility Act
C. Paperwork Reduction Act
D. Science Advisory Board, National Drinking Water Advisory
Council, and Secretary of Health and Human Services
E. Consultation with State, Local, and Tribal Governments
VIII. Request for Public Comment
IX. Instructions to Commenters
X. References
I. Statutory Authority
The Safe Drinking Water Act (SDWA or the Act), as amended in 1986,
requires EPA to publish a ``maximum contaminant level goal'' (MCLG) for
each contaminant which, in the judgment of the EPA Administrator, ``may
have any adverse effect on the health of persons and which are known or
anticipated to occur in public water systems'' (Section 1412(b)(3)(A)).
MCLGs are to be set at a level at which ``no known or anticipated
adverse effects on the health of persons occur and which allows an
adequate margin of safety'' (Section 1412(b)(4)).
At the same time EPA publishes an MCLG, which is a non-enforceable
health goal, it also must publish a National Primary Drinking Water
Regulation (NPDWR) that specifies either a maximum contaminant level
(MCL) or treatment technique (Section 1401(1), 1412(a)(3), and
1412(b)(7)(A)). A treatment technique may be set in lieu of an MCL if
it is not ``economically or technologically feasible'' to determine the
level of a contaminant.
Section 1412(b)(3) of the Act requires EPA to publish regulations
for at least 25 contaminants at three year intervals. Section
1412(b)(9) requires EPA to review each NPDWR every three years and
revise it if appropriate.
Section 1412(b)(7)(C) requires the EPA Administrator to publish a
NPDWR ``specifying criteria under which filtration (including
coagulation and sedimentation, as appropriate) is required as a
treatment technique for public water systems supplied by surface water
sources''. In establishing these criteria, EPA is required to consider
``the quality of source waters, protection afforded by watershed
management, treatment practices (such as disinfection and length of
water storage) and other factors relevant to protection of health''.
This section of the Act also requires EPA to promulgate a NPDWR
requiring disinfection as a treatment technique for all public water
systems and a rule specifying criteria by which variances to this
requirement may be granted.
Section 1445(a)(1) of the Act requires a public water system to
``establish and maintain such records, make such reports, conduct such
monitoring, and provide such information as the Administrator may
reasonably require by regulation . . .''.
Section 1414(c) requires each owner or operator of a public water
system to give notice to persons served by it of any failure to comply
with an MCL, treatment technique, or testing procedure required by a
NPDWR and any failure to comply with any monitoring required pursuant
to section 1445 of the Act.
II. Regulatory Background
Two NPDWRs control disease-causing microorganisms (pathogens) in
public water supplies--the Total Coliform Rule (TCR)(54 FR 27544; June
29, 1989) and the Surface Water Treatment Rule (SWTR)(54 FR 27486; June
29, 1989). A third regulation, the Groundwater Disinfection Rule
(GWDR), which is currently under development, will add further
protection for systems using ground water.
The SWTR met the requirements of Section 1412(b)(7)(C) and, for
surface waters, Section 1412(b)(8) of the SDWA, as amended in 1986. The
SWTR requires all systems using surface water, or ground water under
the direct influence of surface water, to disinfect. In addition, all
such systems are required to filter their water unless they demonstrate
that they have an effective watershed protection program and meet other
EPA-specified requirements (Sec. 141.71). The watershed control program
must minimize the potential for source water contamination by Giardia
cysts and viruses, and typically includes characterization of watershed
hydrology, land ownership by the system, and activities on the
watershed that might have an adverse effect on source water quality.
The rule also requires an annual on-site inspection of all systems that
wish to avoid filtration. This inspection must demonstrate that the
required watershed control program and disinfection treatment processes
are adequately designed and maintained. The SWTR also established MCLGs
of zero for Giardia lamblia, viruses and Legionella.
The SWTR requires all systems to achieve at least 99.9% (3-log)
removal/inactivation of Giardia lamblia cysts, and 99.99% (4-log)
removal/inactivation of enteric viruses. The intention of these
provisions was to provide appropriate multiple barriers of treatment to
control pathogen occurrence in finished drinking water. This rule was
promulgated as a treatment technique rather than an MCL, because EPA
believed that routine monitoring for the pathogens was not economically
or technologically feasible. Another pathogen, Cryptosporidium, was
considered for regulation under the SWTR, but was not addressed,
because EPA lacked sufficient health, occurrence, and water treatment
control data regarding this organism at that time.
The TCR established MCLGs of zero for total coliforms, which
includes fecal coliforms and E. coli. MCLs, monitoring requirements,
and analytical requirements were promulgated for these organisms. The
TCR requires all public water systems that collect fewer than five
samples per month to have an on-site sanitary survey every five years
(ten years for some systems). The purpose of this requirement is to
help ensure the long-term quality and safety of drinking water in small
systems that cannot be accomplished by infrequent coliform monitoring.
The TCR and SWTR were promulgated to minimize both epidemic and
endemic waterborne microbial illness. The public health goal, as
described in the preamble to the SWTR, was to provide treatment to
ensure an acceptable risk of less than one waterborne microbial illness
per year per 10,000 people.
In addition to the SWTR, TCR, and GWDR, EPA is also developing a
rule that would limit concentration levels of disinfectants and the
chemical disinfection byproducts (DBPs) resulting from their use. The
use of chemical disinfectants in water treatment results in a
substantial decrease in waterborne microbial illness and is an integral
part of a multiple-barrier removal/inactivation approach. However,
disinfectants and DBPs may present potential health risks themselves.
DBPs form when disinfectants used for microbial control in drinking
water react with various organic chemicals in the source water. Some of
these are known to be toxic to humans or are considered to be probable
human carcinogens. As such, a number of disinfectants and DBPs were
included on the 1991 Drinking Water Priority List (56 FR 1470, January
14, 1991) as candidates for future regulations. To address these health
issues, EPA is proposing elsewhere in today's Federal Register the
disinfectants/disinfection byproducts (D/DBP) rule, which includes
NPDWRs for several disinfectants and disinfectant byproducts.
To develop the D/DBP Rule, EPA instituted a formal regulation
negotiation process in 1992 with potentially affected parties (57 FR
53866; Nov. 13, 1992). The committee established to negotiate the
regulation included representatives from water utilities, State and
local health and regulatory agencies, environmental groups, consumer
groups, and EPA (hereafter the Negotiating Committee or the Committee).
One of the major goals addressed by the Committee was to develop an
approach that would reduce the level of exposure from disinfectants and
DBPs without undermining the control of pathogens. The intention was to
ensure that drinking water is microbiologically safe at the limits set
for disinfectants and DBPs and that these chemicals do not pose an
unacceptable risk at these limits. The approach in developing this rule
considered the constraints of simultaneously treating water for these
different concerns. As part of this effort, the Negotiating Committee
decided that the SWTR may need to be revised to address health risk
from high densities of pathogens in poor quality source waters and from
the protozoan, Cryptosporidium. If such requirements were deemed
necessary, and could be promulgated concurrently with new D/DBP
regulations (the regulations proposed elsewhere in today's Federal
Register and termed ``Stage 1 D/DBPR''), a system could comply with
both regulations and meet the intended public health goals.
The Negotiating Committee also decided that to develop a reasonable
set of rules, including today's proposed rule, and to understand more
fully the limitations of the current SWTR, additional field data were
critical. Thus, the Committee agreed to the development of an
information collection rule (ICR) that would require, in part, systems
serving a population of 10,000 or greater to determine the density of
specific pathogens in their source water and to characterize their
treatment processes. Under the ICR, systems serving populations greater
than 100,000 would also be required to monitor for pathogens in their
finished water (depending upon the pathogen density in the source
water), and the concentration of DBPs and parameters related to their
formation at various steps in the treatment process. To this end, EPA
proposed the ICR on February 10, 1994 (59 FR 6332) that would require
this additional information. The Committee agreed to the requirements
in the proposed ICR as necessary and reasonable.
According to the regulatory strategy developed by the Committee,
systems serving a population of 10,000 or greater would use the
monitoring and treatment data collected under the ICR to decide what
additional treatment measures, if any, would be necessary to protect
the public from pathogens while controlling for DBPs. This decision
would be based on criteria specified either in amendments to the SWTR
or by guidance. Today's proposed rule includes a variety of regulatory
options, from requiring systems to provide minimum levels of treatment
based upon the density of pathogens in the source water to maintaining
the existing requirements of the SWTR.
According to the Committee's strategy, amendments to the SWTR would
be developed under two rules. The first of these rules, which is
today's proposed rule, would be an interim enhanced SWTR (ESWTR) that
would only pertain to systems serving 10,000 people or greater. Data
collected under the ICR would be used to determine the appropriate
regulatory option(s) under this rule, and then to implement it at the
time systems are required to comply with the Stage 1 D/DBP regulations.
Following the full compilation and analysis of all data collected under
the ICR rule and from other research findings, EPA would propose a
long-term ESWTR with which systems serving fewer than 10,000 people
would comply while also complying with the Stage 1 D/DBP rule. The
long-term ESWTR might also include additional refinements for systems
serving 10,000 people or greater. Today's proposal also satisfies the
provision in section 1412(b)(9) of the SDWA for review of NPDWRs every
three years; the SWTR was promulgated on June 29, 1989, and became
effective in stages, beginning December 31, 1990.
III. Discussion of Proposed Rule
A. Basis for Amending Existing SWTR: Limitations of SWTR
As discussed above, the SWTR requires all systems using surface
water, or ground water under the direct influence of surface water, to
disinfect. It also requires all such systems to filter their water
unless they can demonstrate that they have an effective watershed
control program, meet source water quality criteria, achieve minimum
disinfection requirements, and have no evidence of reported waterborne
disease among the served population. The SWTR also specifies that
systems using surface water must treat water to remove/inactivate at
least 99.9% of the Giardia lamblia cysts and at least 99.99% of the
enteric viruses, regardless of their densities in the source waters.
The SWTR does not require a system to monitor its source water or
drinking water for these pathogens. At the time of promulgation, EPA
recognized a variety of uncertainties and unknowns regarding potential
health risks, but these were not possible to address at that time.
Subsequently, additional information has become available that
indicated possible deficiencies in the SWTR. Some of these deficiencies
are described below.
SWTR Did Not Address Cryptosporidium
During the development of the SWTR, the United States experienced
its first recognized waterborne disease outbreak of cryptosporidiosis,
caused by the protozoan, Cryptosporidium (D'Antonio et al., 1985).
Other outbreaks caused by this pathogen have since been reported both
in the United States and other countries (Smith et al., 1988; Hayes et
al., 1989; Levine and Craun, 1990; Moore et al., 1993; Craun, 1993).
Because of the lack of data before 1989 on Cryptosporidium oocyst
occurrence and removal by treatment, EPA decided to regulate this
pathogen in a future rulemaking, rather than to delay publication of
the SWTR until this data was available. Thus, the SWTR does not now
specifically address Cryptosporidium treatment removal/inactivation
requirements, watershed control requirements for Cryptosporidium for
systems that wish to avoid filtration, or a definition of ground water
under the influence of surface water that includes Cryptosporidium.
Moreover, the assumptions about Giardia reduction under the SWTR may
not be applicable to Cryptosporidium, which, based on laboratory
studies, is much more resistant to common disinfection practices than
is Giardia (Korich et al., 1990; Korich et al., 1992). Since
publication of the SWTR in 1989, some information on Cryptosporidium
occurrence and control measures has been published. EPA will have new
data available shortly from systems that monitor for this organism
under the ICR and from research currently being carried out by the
Agency and the water industry. As a result, EPA believes that it will
soon be in a better position to develop a suitable regulation for
Cryptosporidium.
Specified Pathogen Reductions May Be Inadequate
The 3-log removal/inactivation of Giardia and 4-log removal/
inactivation of enteric viruses required by the SWTR were developed to
provide adequate protection from pathogens in average quality source
water, and thus may be inadequate when a system is supplied by poorer
quality source water with high levels of these or other pathogens. In
developing the SWTR, EPA assumed, on the basis of data available at
that time, that this level of treatment was adequate for the vast
majority of systems.
Additionally, risk assessments for the pathogens of concern had
high degrees of uncertainty, such that the risks associated with a
given level of pathogen contamination were unclear. Moreover, methods
for quantifying these organisms were not generally available.
Therefore, the Agency believed that a simple, yet conservative
treatment requirement was most appropriate. However, it was apparent
during the development of the SWTR that the level of treatment being
specified might not always be adequate. Therefore, the Agency published
associated guidance recommending greater treatment for systems supplied
by poorer quality source waters (EPA, 1991a).
Subsequent data on Giardia and virus densities in source water and
drinking water, however, bring into question the assumption that the
treatment specified in the SWTR was adequate for most systems. These
new data suggest that the concentrations of Giardia cysts and viruses
in the source waters of many systems may be too great for the specified
level of treatment to adequately control waterborne pathogens. For
example, LeChevallier et al. (1991a,b) examined Giardia and
Cryptosporidium levels in the source waters and filtered drinking
waters of 66 surface water systems in 14 States and one Canadian
province. They detected at least one of these two organisms in 97% of
the raw water samples. Giardia densities ranged from 0.04 to 66 cysts/L
(geometric mean of 2.77 cysts/L), while Cryptosporidium densities
ranged from 0.07 to 484 oocysts/L (geometric mean of 2.70 oocysts/L).
These investigators also detected at least one of the two organisms
in the drinking water of 39% of the systems. For those drinking waters
that were positive, Giardia densities ranged from 0.29-64 cysts/100L
(geometric mean 4.45 cysts/100L), while Cryptosporidium densities
ranged from 0.13 to 48 oocysts/100L (geometric mean 1.52 oocysts/100L).
According to the investigators, 78% of the systems that were positive
for Giardia or Cryptosporidium met the turbidity standards specified by
the SWTR. Based on a risk assessment model developed for Giardia, 24%
of the 66 systems might not meet the health goal in the SWTR of no more
than the one Giardia infection annually per 10,000 people per year
(LeChavallier et al., 1991b). (This incidence of infection is a
conservative estimate of illness, since not all infected people become
ill.) This study suggests that the SWTR may need to be revised if an
annual 10-4 risk level, or some other desired risk level, is to be
achieved by all systems in the United States.
EPA used the data in LeChevallier et al. (1991a,b) to calculate the
percentage of systems that use source waters containing various
densities of Giardia cysts. The Agency calculated that about 85% of the
source waters in the study contained 10 cysts/100L or more, while about
45% contained 100 cysts/100L or more. Many of these systems currently
provide four, five, or even six or more logs of removal/inactivation
and therefore are able to achieve EPA's 10-4 annual risk goal.
However, if such systems were to reduce existing levels of disinfection
to more easily meet new D/DBP regulations, and only marginally meet the
three-log removal/inactivation requirement for Giardia specified in the
current SWTR, they could experience significant increases in microbial
risk (Regli et al., 1993; Grubbs et al., 1992; EPA, 1994)).
An epidemiology study by Payment et al. (1991) also suggests that
the pathogen density reductions specified by the SWTR may not be
sufficient for adequate protection. The goal of this study was to
determine the extent to which drinking water caused gastrointestinal
disease in a community served by poor quality source water that was
subjected to full conventional treatment. In this study, the
investigators carried out a trial where 299 households in a community
drank water from a reverse-osmosis water filter, while 307 households
used the usual tapwater. According to the data, 35% of the reported
gastrointestinal illness was associated with the drinking water. The
etiologic agent(s) were not identified, but a plausible explanation is
that pathogens were in the finished water. A recent analysis by Haas et
al. (1993) also suggests that high levels of microbial risk far above
the health goal of the existing SWTR may be occurring in systems with
highly contaminated source waters that may only minimally comply with
the SWTR.
Several other recent studies have shown that Giardia and
Cryptosporidium cysts/oocysts can be found in filtered drinking waters
in systems served by highly contaminated source waters (Clancy, 1993;
EPA, 1993). If treatment is inadequate in reducing pathogens to an
acceptable level, EPA must consider revising and strengthening
treatment requirements. A mitigating factor is that, based upon a
microscopic examination of the cysts/oocysts detected by LeChevallier
et al. (1991b), most of the cysts/oocysts in the drinking water may not
be viable. This observation, however, has not yet been confirmed.
Virus CT Values May Be Greater Than Assumed by SWTR
The SWTR assumes that disinfection more readily controls viruses
than may actually be the case. The Guidance Manual to the SWTR (EPA,
1991a) identifies the disinfection CT values (disinfectant
concentration times the contact time) for viruses. These data are based
on laboratory studies in which a dispersed suspension (i.e., non-cell
associated, non-aggregated) of hepatitis A virus was used. These CT
values relative to the much higher CT values needed for Giardia
inactivation for systems to comply with the SWTR have led to the
assumption by some that systems which satisfactorily control for
Giardia cysts will adequately control for pathogenic viruses. (The CT
values to comply with the level of disinfection inactivation
requirements for viruses in the Guidance Manual to the SWTR are one to
two orders of magnitude below the CT values necessary to achieve the
inactivation requirements for Giardia.)
However this assumption may not always be valid. In environmental
waters, viruses are usually aggregated or associated with cell debris,
some of which may not be removed entirely by filtration processes. Such
cell-associated aggregates are considerably more resistant to
disinfection than free viruses (Williams, 1985; Sobsey, 1991).
Moreover, some pathogenic enteric viruses may be substantially more
resistant to disinfection than hepatitis A (Keswick et al., 1985). In
addition, laboratory studies to determine CT values for viruses, even
with applied uncertainty factors, may underestimate the actual CT
values necessary to achieve the desired level of inactivation, since
viruses in the environment may be hardier and less susceptible to
disinfection.
The detection of viruses in fully treated waters (i.e., after
coagulation, sedimentation, filtration, and disinfection) (Gerba and
Rose, 1990; Payment, 1985; Hurst, 1991) also suggests that viruses in
environmental sources have greater CT values than those published in
the Guidance Manual. Hurst (1991), for example, summarized the
published data on viruses in drinking water, and found that the
percentage of samples positive for viruses ranged from 0 to 100%. In
one study, Payment et al. (1985) detected enteroviruses in 7% of
finished water samples (1,000 L samples from 7 systems), with an
average density of 0.0006 most probable number of cytopathogenic units.
In another study, Payment (1981) detected 1-10 enteroviruses/100L in
most drinking water samples in a system using poor quality source
water.
The above data also suggests that EPA needs to reassess the 4-log
level of treatment required for viruses under the SWTR. Under this
requirement, a system may only provide a 2-log inactivation of viruses
by disinfection and still meet the 4-log overall treatment requirement
(under current EPA guidance, systems using conventional treatment are
assumed to achieve a 2- log removal of viruses by clarification
processes alone). For some systems, virus densities in surface waters
may be sufficiently high to warrant at least a 4-log or greater level
of inactivation by disinfection alone (and a 6-log or greater removal
of viruses with clarification and disinfection) to achieve desired risk
levels (Regli et al., 1991). The Agency would like to determine what
minimum level of disinfection inactivation is necessary for surface
water supplies to ensure adequate virus control, regardless of Giardia
densities. EPA intends to use data from the ICR to: (1) Help clarify
the adequacy of using Giardia as a target organism to control for
viruses in systems with different source water qualities, (2) determine
what assumptions can be made regarding quantification of virus removal
for different treatment processes and disinfection conditions, and (3)
determine what, if any, changes to the SWTR are needed to control
pathogenic viruses.
DBP Rule May Undermine Pathogen Control
Some systems currently exceed the required Giardia and virus
reductions specified by the SWTR. The DBP Rule may potentially
undermine pathogen control in these systems by prompting them to reduce
DBP concentrations at the expense of pathogen control (e.g., by
shifting point of disinfection to later in the treatment chain,
reducing disinfection dose, or switching to a weaker disinfectant such
as chloramines). These systems would still have to comply with the
removal/inactivation criteria in the current SWTR, but would do so with
a lower margin of safety. This situation might result in a substantial
increase in waterborne illness for systems using a poor quality source
water. For example, according to a model developed by EPA (Regli et
al., 1993), a reduction of the MCL for total trihalomethanes (TTHMs)
(one of the toxic byproducts) from 100g/L to 75g/L
could increase the incidence of waterborne giardiasis in some systems
by as many as 10,000 per million people per year, if the existing SWTR
is not amended to require higher levels of treatment for poor quality
source waters.
This situation is further evidence that EPA may need to revise the
SWTR to ensure that measures taken by systems to comply with the
forthcoming DBP Rule do not increase the health risk from pathogens.
B. General Approach for Revising SWTR
Under the negotiated rulemaking, the Negotiating Committee agreed
to propose three rules: (1) ICR, proposed on February 10, 1994 (59 FR
6332), (2) D/DBP regulations (proposed in today's Federal Register),
and (3) ESWTR. EPA is planning to remedy the shortcomings of the SWTR
indicated above through two sequential stages--an interim ESWTR and a
long-term ESWTR. Today's rule proposes the interim ESWTR. The Agency
and the Negotiating Committee decided that this phased approach was
appropriate because of the uncertainties associated with lack of data.
EPA needs much more data on the concentrations of Giardia,
Cryptosporidium, and enteric viruses for various qualities of source
waters, with variations over time and season, to determine the need for
additional treatment. Some members of the Negotiating Committee
believed that health effects information, especially dose response data
for pathogens of concern, is also important to ensure that EPA selects
the most appropriate control option. In addition, EPA needs more field
data on the effectiveness of different types of water treatment for
controlling these pathogens. Data from the ICR and various research
studies would provide much of this information, sufficient in EPA's
view to refine the present proposed interim rule. Additional work would
culminate in a long-term ESWTR that would be protective for all surface
water system sizes (including those that serve fewer than 10,000
people) and would also include possible refinements to any interim
requirements for larger systems. EPA believes that the interim and
long-term ESWTR rules are essential for providing adequate human health
protection; however, some members of the Negotiating Committee believed
that the most appropriate regulatory criteria to provide this
protection are not yet apparent.
Schedule of Regulations
Table I-1 indicates the schedule agreed to by the Negotiating
Committee for proposing, promulgating, and implementing these rules.
Implementation dates for the ICR are indicated under the columns of the
Stage 2 D/DBP rule and ESWTR to reflect the relationship between these
rules. Although the schedule for proposing these rules has slipped
slightly, EPA believes the scheduled promulgation dates for the ESWTR
and D/DBP Rule can still be met.
The Negotiating Committee believes that the December 1996 scheduled
date for promulgating the Stage 1 D/DBP Rule reflects the shortest time
possible by which the interim ESWTR, if necessary, could also be
promulgated. EPA is proposing that the Stage 1 D/DBP regulations and
the interim ESWTR become effective on the same date of June 30, 1998,
for those surface water systems, or ground water systems under the
direct influence of surface water, serving 10,000 people or more. This
strategy is necessary so that systems do not degrade pathogen control
in attempting to comply with the Stage 1 D/DBP regulations.
Table I-1.--Proposed D/DBP, ESWTR, ICR Rule Development Schedule
------------------------------------------------------------------------
Time
line State 1 DBP rule Stage 2 DBP rule ESWTR
------------------------------------------------------------------------
12/93.. .................... Propose information Propose information
collection collection
requirements for requirements for
systems>100k. systems >10k.
3/94... Propose required Propose Stage 2. Propose interim
enhanced MCLs for TTHMs (40 ESWTR for
coagulation for g/l), HAA5 systems>10k.
systems with (30 g/l),
conventional BAT is precursor
treatment. MCLs- removal with
TTHMs (80g/ chlorination.
l), HAA5 (60ug/l),
bromate, chlorite.
Disinfectant limits.
6/94... .................... Promulgate ICR...... Promulgate ICR.
8/94... Close of public .................... Public comment
comment period. period for
proposed ESWTR
closes.
10/94.. .................... Systems>100k begin Systems>100k begin
ICR monitoring. ICR monitoring.
1/95... .................... .................... Systems 10-100k
begin source water
monitoring.
10/95.. .................... SW systems>100k, GW
systems>50k begin
bench/pilot studies
unless source water
quality criteria
met.
11/95.. .................... .................... NOA for monitoring
data, direction of
interim ESWTR.
1/96... .................... .................... Systems>10k
complete ICR
monitoring. End
NOA public comment
period.
3/96... .................... Systems complete ICR Systems>100k
monitoring. complete ICR
monitoring.
12/96.. Promulgate Stage 1.. .................... Promulgate interim
ESWTR for
systems>10k.
6/97... .................... Notice of Propose long-term
availability for ESWTR for
Stage 2 reproposal. systems<10k, possible="" changes="" for="" systems="">10k.
10/97.. .................... Complete and submit
results of bench/
pilot studies.
12/97.. .................... Initiate reproposal--
begin with 3/94
proposal.
6/98... Effective. Effective Close of public Interim ESWTR
for SW systems comment period. effective for
serving systems>10k. 1994-
greater>10k, 6 monitoring data
extended compliance used to determine
date for GAC or treatment level.
membrane technology.
12/98.. .................... Propose for CWSs, Publish long-term
NTNCWSs. ESWTR.
6/00... Stage 1 limits Promulgate Stage 2 Long-term ESWTR
effective for for all CWSs, effective for all
surface water NTNCWSs. system sizes.
systems<10k, gw="" systems="">10k.
1/02... Stage 1 limits Stage 2 effective,
effective for GW compliance for GAC/
systems<10k unless="" membranes="" by="" 2004.="" stage="" 2="" criteria="" supersede.="" ------------------------------------------------------------------------="" epa="" is="" proposing="" to="" delay="" the="" effective="" date="" of="" the="" stage="" 1="" d/dbp="" regulations="" for="" systems="" serving="" less="" than="" 10,000="" people="" until="" june="" 30,="" 2000,="" to="" allow="" such="" systems="" time="" to="" comply="" with="" the="" long-term="" eswtr.="" epa="" believes="" that="" this="" date="" reflects="" the="" shortest="" time="" possible="" that="" would="" allow="" the="" long-term="" eswtr="" to="" be="" proposed,="" promulgated,="" and="" become="" effective,="" thereby="" providing="" the="" necessary="" protection="" from="" any="" downside="" microbial="" risk="" that="" might="" otherwise="" result="" when="" systems="" of="" this="" size="" achieve="" compliance="" with="" the="" stage="" 1="" d/dbp="" rule.="" since="" epa="" is="" proposing="" the="" interim="" eswtr="" before="" systems="" begin="" collecting="" the="" monitoring="" data="" specified="" by="" the="" icr,="" the="" agency's="" final="" direction="" for="" the="" interim="" eswtr="" is="" not="" yet="" clear.="" for="" this="" reason,="" the="" agency="" is="" proposing="" a="" number="" of="" regulatory="" alternatives,="" including="" one="" that="" would="" not="" revise="" the="" existing="" swtr.="" after="" epa="" receives="" and="" processes="" pertinent="" monitoring="" data="" generated="" under="" the="" icr,="" the="" agency="" will="" prepare="" a="" federal="" register="" notice="" (referred="" to="" as="" a="" notice="" of="" availability)="" that="" will="" present="" the="" processed="" data="" to="" the="" public,="" the="" agency's="" interpretation="" of="" that="" data,="" and="" the="" specific="" regulatory="" strategy="" the="" agency="" is="" considering.="" public="" comments="" on="" this="" federal="" register="" package="" will="" influence="" the="" direction="" the="" agency="" ultimately="" takes="" in="" developing="" the="" interim="" eswtr.="" epa="" is="" extending="" the="" comment="" period="" to="" the="" proposed="" interim="" eswtr="" to="" may="" 30,="" 1996,="" which="" is="" beyond="" the="" original="" date="" indicated="" in="" table="" i-1="" (august="" 1994).="" the="" agency="" believes="" this="" adjustment="" is="" necessary="" to="" take="" into="" account="" the="" slippage="" in="" the="" anticipated="" icr="" promulgation="" date,="" which="" will="" necessarily="" also="" result="" in="" a="" slippage="" in="" the="" noa="" publication="" date="" to="" early="" spring="" 1996.="" the="" agency="" believes="" that="" it="" would="" be="" more="" reasonable="" and="" efficient="" for="" epa="" not="" to="" close="" the="" comment="" period="" for="" the="" eswtr="" before="" the="" comment="" period="" ends="" for="" the="" noa.="" unlike="" the="" interim="" eswtr,="" the="" long-term="" eswtr="" will="" cover="" all="" surface="" water="" systems,="" including="" those="" serving="" fewer="" than="" 10,000="" people.="" the="" anticipated="" primary="" thrust="" of="" these="" final="" regulations="" will="" be="" to="" cover="" these="" smaller="" systems,="" rather="" than="" to="" make="" major="" changes="" in="" the="" treatment="" requirements="" for="" larger="" systems,="" although="" some="" refinements="" are="" possible.="" epa="" expects="" the="" criteria="" for="" defining="" the="" specified="" treatment="" needed="" for="" smaller="" systems="" will="" be="" simpler="" than="" that="" for="" the="" larger="" systems="" and="" may,="" for="" example,="" only="" require="" monitoring="" of="" easily="" measured="" indicators="" rather="" than="" pathogens,="" especially="" if="" an="" adequate="" correlation="" is="" observed="" between="" indicator="" and="" pathogen="" densities="" under="" the="" icr="" and="" other="" related="" research.="" pathogen="" monitoring="" in="" small="" systems="" may="" be="" possible,="" if="" inexpensive,="" simple="" analytical="" tests="" for="" viruses="" and/or="" protozoa="" can="" be="" developed,="" evaluated,="" and="" approved.="" epa="" may="" also="" cover="" small="" systems="" by="" using="" the="" icr="" data="" to="" develop="" national="" occurrence="" patterns="" that="" would="" allow="" the="" agency="" to="" establish="" more="" appropriate="" treatment="" criteria="" for="" small="" systems.="" the="" agency="" anticipates="" that="" by="" characterizing="" source="" water="" quality="" using="" any="" one="" or="" a="" combination="" of="" these="" approaches,="" a="" small="" system="" could="" evaluate="" the="" adequacy="" of="" its="" existing="" level="" of="" treatment="" for="" pathogen="" control="" and="" determine="" the="" need="" for="" treatment="" modifications.="" data="" collection="" and="" monitoring="" if="" epa="" decides="" to="" revise="" the="" swtr="" to="" require="" higher="" levels="" of="" treatment="" for="" poorer="" quality="" source="" waters,="" information="" on="" microbial="" densities="" in="" these="" sources="" gathered="" under="" the="" icr="" can="" be="" used="" by="" utilities,="" states="" and="" epa="" to="" determine="" required="" levels="" of="" treatment="" for="" individual="" systems.="" if="" such="" information="" is="" not="" available="" for="" a="" system="" (e.g.,="" if="" a="" system="" that="" had="" not="" performed="" icr="" monitoring="" serves="" a="" community="" which="" grows="" in="" population="" from="" less="" than="" to="" greater="" than="" 10,000="" people),="" epa="" would="" require="" such="" a="" system="" to="" collect="" sufficient="" information="" on="" microbial="" densities="" of="" its="" source="" water="" and="" treatment="" practices="" to="" allow="" the="" state="" to="" make="" this="" determination.="" the="" eswtr="" may="" also="" require="" systems="" serving="" 10,000="" people="" or="" greater="" to="" monitor="" their="" source="" waters="" periodically="" to="" determine="" whether="" changes="" have="" occurred="" in="" the="" quality="" of="" that="" water="" since="" the="" icr="" monitoring.="" any="" deterioration="" in="" source="" water="" quality="" may="" necessitate="" additional="" pathogen="" control="" measures.="" for="" monitoring="" subsequent="" to="" the="" icr="" for="" giardia="" and="" cryptosporidium,="" epa="" intends="" to="" require="" the="" use="" of="" the="" immunofluorescence="" method="" specified="" by="" the="" icr.="" if="" performance="" data="" support="" their="" use,="" newer="" assays="" currently="" under="" development="" may="" be="" considered.="" one="" of="" these="" assays="" is="" based="" on="" the="" observation="" that="" particles="" in="" a="" rotating="" electric="" field="" also="" rotate="" if="" the="" frequency="" is="" right.="" investigators="" using="" this="" principle="" have="" developed="" a="" novel="" assay,="" referred="" to="" as="" the="" electrorotation="" assay,="" that="" can="" apparently="" easily="" distinguish="" between="" the="" target="" organism="" (e.g.,="" cryptosporidium)="" and="" other="" organisms="" and="" particle="" debris="" if="" the="" field="" frequency="" is="" adjusted="" properly.="" at="" this="" frequency,="" the="" target="" organism="" rotates="" and="" other="" particles="" do="" not,="" an="" observation="" easily="" visualized="" under="" the="" microscope.="" preliminary="" data="" reported="" by="" the="" developer="" for="" sterile="" natural="" water="" samples="" spiked="" with="" cryptosporidium="" are="" similar="" to="" those="" obtained="" with="" an="" immunofluorescence="" method.="" if="" these="" data="" are="" confirmed,="" the="" assay="" would="" be="" far="" less="" expensive,="" simpler,="" and="" more="" rapid="" than="" the="" standard="" method.="" in="" addition="" to="" this="" assay,="" other="" potential="" assays="" for="" giardia="" and="" cryptosporidium="" include="" polymerase="" chain="" reaction="" (pcr)="" and="" flow="" cytometry.="" the="" pcr="" is="" a="" powerful="" and="" rapid="" tool="" for="" detecting="" genetic="" material="" that="" is="" initially="" present="" in="" very="" low="" concentrations.="" it="" involves="" the="" amplification="" of="" genetic="" material="" in="" a="" laboratory="" instrument="" until="" sufficient="" quantities="" are="" available="" for="" analysis.="" recent="" publications="" have="" described="" the="" use="" of="" pcr="" in="" detecting="" giardia="" and="" its="" potential="" for="" differentiating="" between="" live="" and="" dead="" cysts="" (mahbubani,="" et="" al.="" 1991).="" flow="" cytometry="" is="" a="" process="" that="" measures="" physical="" or="" chemical="" characteristics="" of="" cells="" passing="" single="" file="" through="" the="" measuring="" apparatus="" in="" a="" fluid="" stream="" (shapiro,="" 1992).="" this="" process="" is="" rapid="" and="" may="" be="" useful="" for="" distinguishing="" between="" and="" quantifying="" giardia="" and="" cryptosporidium.="" c.="" proposed="" maximum="" contaminant="" level="" goal="" and="" treatment="" technique="" for="" cryptosporidium="" as="" stated="" above,="" the="" protozoan="" cryptosporidium="" parvum="" has="" recently="" been="" implicated="" in="" a="" number="" of="" large="" waterborne="" disease="" outbreaks="" in="" the="" united="" states.="" the="" disease="" cryptosporidiosis="" is="" caused="" by="" ingestion="" of="" the="" environmentally-resistant="" oocysts="" of="" cryptosporidium,="" which="" are="" readily="" carried="" by="" the="" waterborne="" route.="" both="" human="" and="" other="" animals="" may="" excrete="" these="" oocysts.="" transmission="" of="" this="" disease="" often="" occurs="" through="" ingestion="" of="" the="" infective="" oocysts="" from="" contaminated="" water="" or="" food,="" but="" may="" also="" result="" from="" direct="" or="" indirect="" contact="" with="" infected="" persons="" or="" animals.="" symptoms="" of="" cryptosporidiosis="" include="" diarrhea,="" abdominal="" discomfort,="" nausea,="" vomiting,="" dehydration,="" weight="" loss,="" and="" other="" gastrointestinal="" symptoms="" (current="" et="" al.,="" 1983).="" these="" may="" persist="" for="" several="" days="" to="" several="" months.="" young="" children="" and="" immunocompromised="" persons="" are="" most="" susceptible="" to="" infection="" (wittenberg="" et="" al.,="" 1989;="" de="" mol="" et="" al.,="" 1984),="" but="" people="" of="" all="" ages="" may="" become="" infected.="" while="" cryptosporidiosis="" is="" generally="" a="" self-limiting="" disease="" with="" a="" complete="" recovery="" in="" otherwise="" healthy="" persons,="" it="" can="" be="" very="" serious="" in="" immunosuppressed="" persons,="" such="" as="" persons="" with="" aids,="" those="" receiving="" treatment="" for="" certain="" types="" of="" cancer,="" and="" organ-transplant="" recipients="" (de="" mol="" et="" al.,="" 1984;="" cdc,="" 1982).="" several="" studies="" in="" great="" britain="" have="" documented="" a="" waterborne="" route="" for="" cryptosporidiosis="" in="" aids="" patients="" and="" in="" persons="" receiving="" immunosuppressive="" transplant="" therapy="" (casemore,="" 1990).="" there="" appears="" to="" be="" an="" immune="" response="" to="" cryptosporidium,="" but="" it="" is="" not="" known="" if="" this="" results="" in="" protection="" (fayer="" and="" ungar,="" 1986).="" data="" suggest="" that="" a="" person,="" once="" infected,="" can="" transmit="" this="" infection="" by="" direct="" contact="" to="" other="" susceptible="" persons="" (casemore="" and="" jackson,="" 1984).="" between="" 1984-1993,="" there="" were="" a="" number="" of="" reported="" outbreaks="" of="" significant="" waterborne="" cryptosporidiosis="" in="" the="" u.s.="" and="" great="" britain,="" totaling="" many="" tens="" of="" thousands="" of="" cases="" (d'antonio="" et="" al.,="" 1985;="" smith="" et="" al.,="" 1988;="" hayes="" et="" al.,="" 1989;="" herwaldt="" et="" al.,="" 1991;="" levine="" and="" craun,="" 1990;="" moore="" et="" al.,="" 1993).="" the="" trend="" in="" numbers="" of="" outbreaks="" has="" been="" on="" the="" increase,="" probably="" due="" to="" greater="" recognition="" and="" subsequent="" reporting="" of="" cryptosporidium="" in="" outbreaks="" during="" recent="" years.="" prevalence="" data="" for="" human="" cryptosporidiosis="" in="" all="" age="" groups="" ranged="" from="" 1="" to="" 2="" percent="" in="" europe,="" 0.6="" to="" 4.3="" percent="" for="" north="" america,="" and="" 3="" to="" 20="" percent="" for="" asia,="" australia,="" africa,="" and="" south="" america="" (epa,="" 1993).="" the="" role="" of="" water="" in="" the="" transmission="" of="" cryptosporidiosis="" has="" been="" proven.="" however,="" the="" known="" percentages="" of="" cases="" from="" water="" compared="" to="" other="" routes="" may="" substantially="" under-="" represent="" the="" water="" route.="" the="" route="" of="" transmission="" for="" many="" cases="" of="" cryptosporidiosis="" was="" not="" determined,="" but="" may="" have="" been="" waterborne.="" during="" the="" spring="" of="" 1993,="" there="" was="" a="" severe="" waterborne="" disease="" outbreak="" of="" cryptosporidiosis="" in="" milwaukee,="" wisconsin,="" with="" an="" estimated="" 400,000="" cases="" of="" diarrhea="" and="" apparently="" several="" deaths="" associated="" with="" the="" disease="" in="" severely="" immunocompromised="" persons.="" another="" recent="" outbreak="" of="" waterborne="" cryptosporidiosis="" occurred="" in="" jackson="" county,="" oregon,="" during="" the="" winter="" and="" spring="" of="" 1992,="" where="" as="" many="" as="" 15,000="" people="" (10%="" of="" the="" population)="" displayed="" cryptosporidiosis-like="" symptoms="" (awwa,="" 1992).="" it="" is="" estimated="" that="" over="" 162="" million="" people="" are="" served="" by="" public="" water="" systems="" using="" surface="" water,="" most="" of="" which="" are="" filtered="" and="" disinfected.="" of="" these,="" as="" of="" june="" 1989,="" an="" estimated="" 21="" million="" people="" were="" receiving="" unfiltered="" surface="" water="" that="" is="" only="" disinfected.="" epa="" anticipates="" that,="" as="" a="" result="" of="" the="" swtr,="" more="" than="" 80="" percent="" of="" the="" unfiltered="" systems="" will="" install="" filtration.="" nevertheless,="" in="" spite="" of="" filtration="" and="" disinfection,="" cryptosporidium="" oocysts="" have="" been="" found="" in="" filtered="" drinking="" water="" (lechevallier="" et="" al.,="" 1991b;="" epa,="" 1993)="" and="" most="" waterborne="" outbreaks="" of="" cryptosporidiosis="" have="" been="" associated="" with="" filtered="" surface="" water="" systems.="" therefore,="" it="" appears="" that="" surface="" water="" systems="" that="" filter="" and="" disinfect="" may="" still="" be="" vulnerable="" to="" cryptosporidium,="" depending="" on="" source="" water="" quality="" and="" treatment="" effectiveness.="" in="" addition,="" some="" surface="" water="" systems="" that="" were="" able="" to="" avoid="" filtration="" under="" the="" swtr="" may="" need="" to="" filter="" to="" provide="" adequate="" protection="" against="" cryptosporidium.="" epa="" is="" proposing="" an="" mclg="" for="" cryptosporidium="" because="" cryptosporidium="" oocysts="" have="" been="" demonstrated="" to="" be="" a="" significant="" health="" threat="" for="" all="" persons="" consuming="" untreated="" or="" inadequately="" treated="" surface="" waters="" and="" ground="" waters="" under="" the="" influence="" of="" surface="" waters.="" the="" proposed="" mclg="" is="" based="" upon="" animal="" studies="" and="" the="" human="" epidemiology="" of="" waterborne="" outbreaks="" of="" cryptosporidiosis.="" while="" it="" is="" clear="" that="" cryptosporidium="" can="" infect="" humans,="" dose-="" response="" data="" for="" infection="" and="" illness="" rates="" are="" lacking.="" therefore,="" risk="" assessments="" for="" this="" organism="" based="" on="" human="" data="" are="" not="" currently="" possible.="" however,="" the="" results="" of="" several="" animal="" studies="" have="" been="" published="" on="" the="" infectious="" dose="" of="" cryptosporidium="" oocysts.="" korich="" et="" al.="" (1990)="" examined="" neonatal="" mice="" inoculated="" with="" 600,="" 6,000,="" or="" 60,000="" oocysts.="" in="" this="" study,="" the="" mean="" infectious="" dose="" (id50)="" was="" determined="" by="" initial="" experiments="" to="" be="" 60="" oocysts.="" mice="" receiving="" 60="" or="" more="" oocysts="" were="" typically="" infected="" while="" those="" receiving="" less="" than="" 60="" oocysts="" often="" did="" not="" demonstrate="" any="" infection.="" the="" work="" of="" miller="" et="" al.="" (1990),="" while="" limited="" because="" of="" the="" small="" number="" of="" animals="" tested,="" was="" conducted="" on="" macaque="" monkeys.="" ten="" oocysts="" via="" oral="" intubation="" were="" capable="" of="" causing="" infection="" and="" the="" signs="" and="" symptoms="" resembled="" the="" effects="" seen="" in="" children="" and="" immunocompromised="" humans="" with="" cryptosporidiosis.="" feeding="" studies="" in="" mice="" described="" by="" ernest="" et="" al.="" (1986)="" indicated="" that="" inoculation="" with="" 100,="" 500,="" or="" 1,000="" oocysts="" caused="" infection="" in="" 22,="" 66,="" and="" 78="" percent,="" respectively,="" of="" the="" mice="" in="" each="" dose="" group.="" studies="" to="" date="" strongly="" suggest="" that="" there="" are="" strain="" differences="" or="" virulence="" factors="" that="" may="" greatly="" influence="" the="" ability="" of="" cryptosporidium="" to="" infect="" humans="" and="" animals="" via="" the="" oral="" route.="" the="" comparative="" infectivity="" of="" specific="" strains="" for="" humans="" and="" various="" animal="" models="" has="" not="" been="" accurately="" established.="" the="" use="" of="" animal="" models="" for="" determining="" infectious="" dose="" may="" overestimate="" the="" number="" of="" oocysts="" required="" for="" human="" infection.="" also,="" technical="" questions="" remain="" that="" affect="" epa's="" consideration="" of="" the="" reliability="" and="" meaning="" of="" the="" available="" data.="" for="" example,="" the="" length="" of="" time="" and="" procedures="" used="" in="" storage="" of="" oocysts="" in="" the="" laboratory="" before="" infectivity="" studies="" begin="" may="" influence="" infectivity="" determinations.="" there="" are="" currently="" no="" proven="" in-vitro="" methods="" to="" determine="" whether="" oocysts="" used="" in="" testing="" are="" all="" viable.="" because="" some="" strains="" of="" cryptosporidium="" parvum="" appear="" to="" be="" highly="" infectious,="" and="" because="" there="" is="" no="" current="" generally="" accepted="" practical="" means="" for="" distinguishing="" whether="" detected="" oocysts="" are="" viable="" or="" for="" determining="" the="" infectious="" dose="" of="" any="" particular="" strain,="" epa="" believes="" this="" organism="" should="" be="" assumed="" to="" be="" without="" an="" infectivity="" threshold="" for="" purposes="" of="" this="" rule.="" that="" is,="" consumption="" of="" one="" cryptosporidium="" oocyst="" would="" be="" considered="" sufficient="" to="" initiate="" human="" infection="" as="" a="" possible="" consequence.="" also,="" direct="" person-to-person="" spread="" of="" infection="" may="" readily="" occur,="" thus="" magnifying="" the="" significance="" of="" the="" original="" waterborne="" infection.="" therefore,="" the="" presence="" of="" this="" organism="" at="" any="" level="" in="" consumed="" drinking="" water="" cannot="" be="" considered="" safe="" for="" human="" consumption.="" for="" these="" reasons="" and="" to="" be="" consistent="" with="" epa="" drinking="" water="" standards="" for="" giardia,="" enteric="" viruses,="" legionella,="" e.="" coli="" and="" coliform="" bacteria,="" epa="" proposes="" that="" the="" mclg="" for="" cryptosporidium="" oocysts="" in="" water="" be="" zero.="" public="" comments="" are="" requested="" on="" this="" rationale="" for="" setting="" an="" mclg="" of="" zero="" and="" a="" treatment="" technique="" for="" cryptosporidium.="" d.="" proposed="" revisions="" to="" swtr="" under="" all="" treatment="" alternatives="" this="" section="" proposes="" three="" revisions="" of="" the="" swtr="" that="" would="" apply="" regardless="" of="" which="" of="" the="" four="" treatment="" alternatives="" in="" section="" e="" that="" epa="" selects.="" this="" section="" also="" requests="" public="" comment="" on="" several="" additional="" measures="" (section="" 4,="" below).="" 1.="" inclusion="" of="" cryptosporidium="" in="" definition="" of="" ``groundwater="" under="" the="" direct="" influence="" of="" surface="" water''="" the="" swtr="" at="" 40="" cfr="" 141.2="" defines="" ``groundwater="" under="" the="" direct="" influence="" of="" surface="" water''="" as="" ``any="" water="" beneath="" the="" surface="" of="" the="" ground="" with="" (1)="" significant="" occurrence="" of="" insects="" or="" other="" macroorganisms,="" algae,="" or="" large-diameter="" pathogens="" such="" as="" giardia="" lamblia,="" or="" (2)="" significant="" and="" relatively="" rapid="" shifts="" in="" water="" characteristics="" such="" as="" turbidity,="" temperature,="" conductivity,="" or="" ph="" which="" closely="" correlate="" to="" climatological="" or="" surface="" water="" conditions="" *="" *="" *''.="" systems="" using="" such="" ground="" waters="" as="" a="" source="" for="" drinking="" water="" are="" subject="" to="" the="" provisions="" of="" the="" swtr.="" determination="" of="" whether="" a="" ground="" water="" is="" under="" the="" direct="" influence="" of="" surface="" water="" requires="" careful="" evaluation="" of="" site-specific="" information="" on="" water="" quality,="" well="" construction="" characteristics,="" and="" hydrogeology.="" epa="" defined="" groundwater="" under="" the="" direct="" influence="" of="" surface="" water="" in="" the="" swtr="" to="" ensure="" that="" public="" water="" supply="" systems="" using="" this="" type="" of="" source="" water="" would="" provide="" appropriate="" treatment="" to="" minimize="" health="" risks="" from="" pathogens.="" since="" viruses="" and="" bacteria="" are="" known="" to="" contaminate="" true="" ground="" waters,="" epa="" focused="" attention="" on="" those="" contaminants="" that="" do="" not="" normally="" occur="" in="" true="" ground="" waters="" and="" whose="" presence="" suggests="" direct="" surface="" water="" contamination.="" among="" those="" contaminants="" are="" certain="" pathogenic="" protozoa,="" such="" as="" cryptosporidium="" parvum="" and="" giardia="" lamblia.="" these="" protozoa="" are="" common="" in="" surface="" waters.="" at="" the="" time="" of="" promulgation="" of="" the="" swtr,="" routine="" methods="" for="" detection="" of="" cryptosporidium="" were="" not="" generally="" available="" and,="" therefore,="" cryptosporidium="" was="" not="" specifically="" addressed="" under="" the="" definition="" of="" ``groundwater="" under="" the="" direct="" influence="" of="" surface="" water''.="" epa="" is="" currently="" revising="" its="" existing="" guidance="" (epa,="" 1991a;="" epa,="" 1992)="" to="" address="" this="" issue.="" epa="" proposes="" to="" amend="" the="" swtr="" by="" including="" cryptosporidium="" in="" the="" definition="" of="" a="" ``ground="" water="" under="" the="" direct="" influence="" of="" surface="" water''.="" under="" the="" rule,="" a="" system="" using="" ground="" water="" considered="" vulnerable="" to="" cryptosporidium="" contamination="" would="" be="" subject="" to="" the="" provisions="" of="" the="" swtr.="" the="" agency="" proposes="" that="" this="" determination="" be="" made="" by="" the="" state="" for="" individual="" sources="" using="" state-established="" criteria="" for="" requirements="" and="" documentation.="" the="" agency="" believes="" that="" this="" would="" allow="" states="" sufficient="" flexibility="" to="" accommodate="" local="" and="" regional="" hydrogeological="" conditions="" and="" maintain="" consistency="" with="" state="" well="" construction="" requirements,="" watershed="" management="" policies,="" and="" wellhead="" protection="" plans.="" because="" cryptosporidium="" can="" occur="" episodically,="" the="" inability="" to="" detect="" this="" organism="" in="" a="" ground="" water="" at="" any="" given="" time="" would="" not="" necessarily="" suggest="" that="" ground="" water="" is="" not="" under="" the="" direct="" influence="" of="" surface="" water.="" the="" presence="" of="" cryptosporidium,="" however,="" would="" indicate="" fecal="" contamination="" and="" direct="" influence="" of="" surface="" water.="" the="" swtr="" does="" not="" necessarily="" require="" a="" system="" that="" uses="" ground="" water="" to="" filter="" if="" it="" detects="" cryptosporidium,="" giardia,="" or="" other="" contaminants="" associated="" with="" surface="" water="" in="" the="" ground="" water,="" or="" if="" the="" groundwater="" is="" categorized="" as="" being="" under="" the="" direct="" influence="" of="" surface="" water.="" the="" presence="" of="" these="" organisms="" may="" be="" the="" result="" of="" faulty="" well="" construction="" that="" can="" be="" remedied="" by="" inexpensive="" measures.="" also,="" the="" rule="" allows="" states="" to="" grant="" removal/inactivation="" credit="" for="" the="" ``natural="" disinfection''="" achieved="" during="" flow="" from="" the="" surface="" water="" source="" to="" a="" well;="" such="" natural="" disinfection="" could="" mitigate="" the="" treatment="" level="" that="" might="" otherwise="" be="" required.="" for="" the="" state="" to="" grant="" removal/inactivation="" credit="" for="" a="" system,="" that="" system="" would="" have="" to="" demonstrate="" the="" extent="" to="" which="" giardia="" and="" cryptosporidium="" are="" removed="" by="" site-specific="" natural="" removal="" processes="" before="" the="" water="" enters="" the="" well.="" however,="" strategies="" for="" granting="" such="" credits="" are="" currently="" limited="" because="" accurate="" pathogen="" removal/inactivation="" rates="" during="" transport="" through="" the="" ground="" cannot="" yet="" be="" easily="" predicted.="" epa="" solicits="" comment="" on="" the="" inclusion="" of="" cryptosporidium="" in="" the="" determination="" of="" ground="" water="" under="" the="" influence="" of="" surface="" water,="" on="" the="" larger="" consideration="" of="" revisions="" to="" guidance="" on="" this="" issue,="" and="" on="" the="" most="" appropriate="" procedures="" for="" determining="" removal/inactivation="" credits="" and="" treatment="" requirements="" for="" systems="" using="" ground="" waters="" under="" the="" direct="" influence="" of="" surface="" water.="" 2.="" inclusion="" of="" cryptosporidium="" in="" watershed="" control="" requirements="" the="" swtr="" at="" sec.="" 141.71="" specifies="" the="" conditions="" under="" which="" a="" public="" water="" system="" using="" a="" surface="" water="" source="" can="" avoid="" filtration.="" among="" the="" conditions="" is="" a="" requirement="" that="" the="" system="" maintain="" a="" watershed="" control="" program="" that="" minimizes="" the="" potential="" for="" source="" water="" contamination="" by="" giardia="" lamblia="" and="" viruses="" (sec.="" 141.71(b)(2)).="" this="" program="" must="" include="" a="" characterization="" of="" the="" watershed="" hydrology="" characteristics,="" land="" ownership,="" and="" activities="" which="" may="" have="" an="" adverse="" effect="" on="" source="" water="" quality.="" epa="" is="" proposing="" to="" extend="" the="" watershed="" control="" requirements="" to="" include="" the="" control="" of="" cryptosporidium="" in="" the="" source="" water="" in="" a="" manner="" analogous="" to="" the="" existing="" requirements="" in="" sec.="" 141.71(b)(2)="" for="" giardia="" cysts="" and="" viruses.="" the="" rationale="" is="" that="" cryptosporidium="" is="" a="" pathogen="" that="" cannot="" be="" easily="" controlled="" with="" conventional="" disinfection="" practices,="" and="" therefore="" its="" presence="" in="" source="" water="" serving="" unfiltered="" surface="" water="" systems="" must="" be="" limited.="" specifically,="" cryptosporidium="" would="" be="" included="" in="" the="" watershed="" protection="" control="" provisions="" wherever="" giardia="" is="" mentioned.="" 3.="" sanitary="" surveys="" for="" all="" surface="" water="" systems="" the="" swtr="" at="" sec.="" 141.71(b)(3)="" requires="" that="" systems="" wishing="" to="" avoid="" filtration="" must="" be="" subject="" to="" an="" annual="" on-site="" inspection="" performed="" by="" the="" state="" or="" a="" party="" approved="" by="" the="" state.="" the="" results="" of="" this="" system="" inspection="" must="" indicate="" to="" the="" state's="" satisfaction="" that="" the="" disinfection="" treatment="" process="" and="" the="" watershed="" control="" program="" are="" adequately="" designed="" and="" maintained.="" epa="" proposes="" to="" amend="" the="" swtr="" to="" require="" all="" systems="" that="" use="" surface="" water,="" or="" ground="" water="" under="" the="" direct="" influence="" of="" surface="" water,="" to="" have="" a="" periodic="" sanitary="" survey,="" regardless="" of="" whether="" they="" filter="" or="" not.="" states="" would="" be="" required="" to="" review="" the="" results="" of="" each="" sanitary="" survey="" to="" determine="" whether="" the="" existing="" monitoring="" and="" treatment="" practices="" for="" that="" system="" are="" adequate,="" and="" if="" not,="" what="" corrective="" measures="" are="" needed="" to="" provide="" adequate="" drinking="" water="" quality.="" if="" epa="" publishes="" a="" regulation="" that="" requires="" systems="" to="" treat="" their="" water="" on="" the="" basis="" of="" pathogen="" densities="" in="" the="" source="" water="" (see="" section="" e="" below),="" the="" agency="" would="" require="" systems,="" as="" part="" of="" the="" sanitary="" survey,="" to="" assess="" quantitatively="" whether="" the="" source="" water="" quality="" has="" changed="" sufficiently="" since="" the="" previous="" sanitary="" survey="" to="" warrant="" changes="" in="" treatment="" practice.="" under="" this="" rule,="" the="" system="" would="" be="" responsible="" for="" insuring="" that="" the="" sanitary="" survey="" is="" accomplished.="" only="" the="" state="" or="" an="" agent="" approved="" by="" the="" state="" would="" be="" able="" to="" conduct="" this="" sanitary="" survey,="" except="" in="" the="" unusual="" case="" where="" a="" state="" has="" not="" yet="" implemented="" this="" requirement,="" i.e.,="" the="" state="" has="" neither="" performed="" a="" sanitary="" survey="" nor="" generated="" a="" list="" of="" approved="" agents.="" for="" these="" unusual="" cases,="" the="" agency="" solicits="" comment="" on="" what="" epa="" prerequisites,="" if="" any,="" should="" be="" specified="" in="" the="" rule="" or="" guidance="" for="" individuals="" performing="" sanitary="" surveys="" (e.g.,="" bs="" degree="" in="" environmental="" engineering,="" professional="" engineer="" certificate,="" sanitarians,="" etc.).="" sanitary="" surveys="" are="" defined="" in="" sec.="" 141.2="" as="" ``an="" on-site="" review="" of="" the="" water="" source,="" facilities,="" equipment,="" operation="" and="" maintenance="" of="" a="" public="" water="" system="" for="" the="" purpose="" of="" evaluating="" the="" adequacy="" of="" such="" sources,="" facilities,="" equipment,="" operation="" and="" maintenance="" for="" producing="" and="" distributing="" safe="" drinking="" water.''="" guidance="" for="" conducting="" a="" sanitary="" survey="" for="" unfiltered="" systems="" appears="" in="" the="" swtr="" guidance="" manual="" (epa,="" 1991),="" even="" though="" such="" a="" survey="" is="" not="" specifically="" required="" by="" the="" swtr.="" epa="" solicits="" comment="" on="" how="" this="" guidance="" manual="" should="" be="" revised="" to="" address="" concerns="" for="" filtered="" systems,="" and="" for="" cryptosporidium.="" the="" requirement="" for="" a="" sanitary="" survey="" under="" this="" rule="" would="" be="" similar="" to="" that="" in="" the="" tcr,="" which="" requires="" periodic="" sanitary="" surveys="" for="" some="" systems.="" specifically,="" the="" tcr="" at="" sec.="" 141.21(d)="" requires="" periodic="" sanitary="" surveys="" for="" systems="" that="" collect="" fewer="" than="" five="" routine="" samples="" per="" month.="" these="" surveys="" are="" performed="" by="" the="" state="" or="" a="" party="" approved="" by="" the="" state.="" the="" results="" of="" the="" sanitary="" surveys="" are="" to="" be="" used="" by="" the="" state="" to="" determine="" whether="" the="" monitoring="" frequency="" is="" appropriate,="" and="" if="" not,="" what="" the="" new="" frequency="" should="" be="" and="" whether="" the="" system="" needs="" to="" undertake="" any="" specific="" measures="" to="" improve="" water="" quality.="" these="" surveys="" are="" to="" be="" performed="" every="" five="" years="" or="" ten="" years,="" depending="" on="" circumstances.="" these="" surveys="" are="" somewhat="" more="" extensive="" than="" the="" on-site="" inspection="" required="" under="" the="" existing="" swtr="" and="" include="" an="" evaluation="" of="" the="" distribution="" system.="" in="" addition="" to="" the="" sanitary="" survey="" in="" the="" tcr="" and="" the="" proposed="" requirement="" for="" surface="" water="" systems,="" epa="" intends="" to="" propose="" a="" sanitary="" survey="" requirement="" in="" the="" forthcoming="" groundwater="" disinfection="" rule="" for="" all="" public="" water="" supply="" systems="" using="" groundwater="" that="" wish="" to="" avoid="" disinfection.="" the="" agency="" believes="" that="" periodic="" sanitary="" surveys,="" along="" with="" appropriate="" corrective="" measures,="" are="" indispensable="" for="" assuring="" the="" long-term="" quality="" and="" safety="" of="" drinking="" water.="" many="" states="" already="" perform="" sanitary="" surveys="" on="" most="" or="" all="" systems.="" by="" taking="" steps="" to="" correct="" deficiencies="" exposed="" by="" a="" sanitary="" survey,="" the="" system="" provides="" an="" additional="" barrier="" to="" microbial="" contamination="" of="" drinking="" water.="" compliance="" with="" this="" requirement="" would="" not="" eliminate="" the="" requirement="" for="" unfiltered="" systems="" to="" conduct="" annual="" on-site="" inspections,="" although="" applicable="" information="" from="" these="" on-site="" inspections="" could="" be="" used="" to="" satisfy="" some="" elements="" of="" the="" sanitary="" survey.="" during="" the="" years="" when="" the="" sanitary="" survey="" is="" conducted,="" the="" sanitary="" survey="" would="" fulfill="" the="" on-site="" inspection="" requirement.="" with="" promulgation="" of="" these="" rules,="" epa="" hopes="" to="" focus="" more="" attention="" on="" watersheds="" and="" watershed="" protection="" activities="" to="" enhance="" and="" maintain="" the="" quality="" of="" both="" surface="" waters="" and="" ground="" waters="" as="" sources="" for="" drinking="" water.="" the="" agency="" recognizes="" that="" in="" many="" areas="" of="" the="" united="" states,="" watersheds="" that="" serve="" as="" drinking="" water="" sources="" are="" increasingly="" vulnerable="" to="" degradation.="" moreover,="" the="" current="" status="" of="" technology="" and="" scarce="" funding="" may="" limit="" the="" levels="" of="" water="" treatment="" reasonably="" possible.="" therefore,="" the="" agency="" wishes="" to="" minimize="" the="" contamination="" of="" source="" waters="" to="" maintain="" or="" improve="" the="" health="" benefits="" from="" drinking="" water="" treatment.="" while="" the="" rule="" proposed="" here="" derives="" from="" provisions="" of="" the="" sdwa,="" protection="" of="" watersheds="" is="" also="" consistent="" with="" provisions="" of="" the="" clean="" water="" act.="" one="" issue="" that="" the="" negotiating="" committee="" considered="" throughout="" the="" negotiation="" process="" was="" the="" relationship="" and="" role="" of="" watershed="" protection="" to="" these="" regulations.="" the="" committee="" sought="" to="" promote="" watershed="" protection="" and="" to="" provide="" incentives="" to="" establish="" new="" watershed="" protection="" programs="" and="" to="" improve="" existing="" ones.="" this="" goal="" was="" prompted="" by="" the="" benefits="" that="" watershed="" protection="" provides="" not="" only="" for="" disinfectant="" byproduct="" control,="" but="" for="" the="" control="" of="" a="" wide="" range="" of="" potential="" drinking="" water="" contaminants.="" watershed="" protection="" minimizes="" pathogen="" contamination="" in="" water="" sources,="" and="" hence="" the="" amount="" of="" physical="" treatment="" and/or="" disinfectant="" needed="" to="" achieve="" a="" specified="" level="" of="" microbial="" risk="" in="" a="" finished="" water="" supply.="" it="" also="" may="" reduce="" the="" level="" of="" turbidity,="" pesticides,="" volatile="" organic="" compounds,="" and="" other="" synthetic="" organic="" drinking="" water="" contaminants="" found="" in="" some="" water="" sources.="" watershed="" protection="" results="" in="" benefits="" for="" water="" supply="" systems="" by="" minimizing="" reservoir="" sedimentation="" and="" eutrophication="" and="" by="" reducing="" water="" treatment="" operation="" and="" maintenance="" costs.="" watershed="" protection="" also="" provides="" other="" environmental="" benefits="" through="" improvements="" in="" fisheries="" and="" ecosystem="" protection.="" the="" types="" of="" watershed="" programs="" that="" the="" committee="" wished="" to="" encourage="" are="" those="" that="" consider="" agricultural="" controls,="" silvicultural="" controls,="" urban="" non-point="" controls,="" point="" discharge="" controls,="" and="" land="" use="" protection="" that="" are="" tailored="" to="" the="" environmental="" and="" human="" characteristics="" of="" the="" individual="" watershed.="" these="" characteristics="" include="" the="" hydrology="" and="" geology="" of="" the="" watershed;="" the="" nature="" of="" human="" sources="" of="" contaminants;="" and="" the="" legal,="" financial="" and="" political="" constraints="" of="" entities="" that="" affect="" the="" watershed.="" sanitary="" survey="" frequency.="" epa="" is="" considering="" requiring="" sanitary="" surveys="" either="" every="" three="" years="" or="" every="" five="" years,="" and="" requests="" public="" comment="" on="" this="" issue.="" there="" is="" a="" major="" concern="" that="" changes="" over="" time="" in="" watershed="" characteristics,="" such="" as="" those="" resulting="" from="" development="" or="" other="" changes="" in="" land="" use,="" may="" degrade="" surface="" source="" water="" quality="" significantly.="" treatment="" facilities="" and="" distribution="" systems="" likewise="" may="" deteriorate="" over="" time.="" it="" is="" important="" to="" address="" such="" adverse="" changes="" as="" soon="" as="" possible.="" consequently,="" more="" frequent="" sanitary="" surveys="" should="" result="" in="" safer="" and="" more="" reliable="" drinking="" water.="" this="" is="" the="" advantage="" of="" a="" three-year="" survey="" over="" a="" five-year="" survey.="" yet="" a="" survey="" every="" five="" years="" is="" less="" expensive="" and="" is="" more="" consistent="" with="" the="" provisions="" of="" the="" tcr.="" epa="" considers="" a="" five-year="" frequency="" to="" be="" minimal="" for="" assessing="" watershed="" and="" system="" conditions="" associated="" with="" surface="" waters.="" to="" provide="" adequate="" lead="" time="" to="" the="" state="" for="" implementing="" any="" sanitary="" survey="" requirement,="" epa="" would="" not="" require="" systems="" to="" complete="" the="" initial="" sanitary="" survey="" until="" five="" years="" after="" the="" effective="" date="" of="" this="" rule.="" this="" lead="" time="" would="" not="" apply="" to="" systems="" that="" collect="" fewer="" than="" five="" samples="" per="" month="" under="" the="" tcr,="" since="" they="" should="" already="" have="" had="" their="" initial="" survey.="" epa="" does="" not="" believe="" this="" sanitary="" survey="" requirement="" would="" be="" onerous="" to="" systems,="" since="" systems="" collecting="" fewer="" than="" five="" samples/="" month="" (i.e.,="" serving="" fewer="" than="" 4101="" people)="" are="" already="" required="" to="" conduct="" sanitary="" surveys="" under="" the="" tcr,="" and="" larger="" systems="" should="" have="" greater="" financial="" resources="" than="" these="" smaller="" ones.="" 4.="" possible="" supplemental="" requirements="" a.="" uncovered="" finished="" water="" reservoirs.="" epa="" guidelines="" recommend="" that="" all="" finished="" water="" reservoirs="" and="" storage="" tanks="" be="" covered="" (epa,="" 1991a,b).="" the="" american="" water="" works="" association="" (awwa)="" also="" has="" issued="" a="" policy="" statement="" strongly="" supporting="" the="" covering="" of="" reservoirs="" that="" store="" potable="" water="" (awwa,="" 1993).="" in="" addition,="" a="" workshop="" in="" 1981="" convened="" by="" epa,="" in="" conjunction="" with="" the="" american="" society="" for="" microbiology,="" to="" advise="" epa="" on="" a="" variety="" of="" drinking="" water="" issues="" recommended="" that="" epa="" require="" systems="" to="" cover="" all="" new="" finished="" water="" reservoirs="" (epa,="" 1983).="" by="" covering="" reservoirs="" and="" storage="" tanks,="" systems="" would="" reduce="" the="" potential="" for="" contamination="" of="" the="" finished="" water="" by="" pathogens="" and="" hazardous="" chemicals.="" it="" would="" also="" limit="" the="" potential="" for="" taste="" and="" odor="" problems="" and="" increased="" operation="" and="" maintenance="" costs="" resulting="" from="" environmental="" factors="" such="" as="" sunlight="" (bailey="" and="" lippy,="" 1978).="" potential="" sources="" of="" contamination="" to="" uncovered="" reservoirs="" and="" tanks="" include="" airborne="" chemicals,="" surface="" water="" runoff,="" animal="" carcasses,="" animal="" or="" bird="" droppings,="" growth="" of="" algae="" and="" other="" aquatic="" organisms="" due="" to="" sunlight="" that="" results="" in="" biomass,="" and="" violations="" of="" reservoir="" security="" (bailey="" and="" lippy,="" 1978).="" because="" of="" these="" adverse="" consequences,="" epa="" is="" considering="" whether="" to="" issue="" regulations="" that="" require="" systems="" to="" cover="" finished="" water="" reservoirs="" and="" storage="" tanks.="" the="" agency="" solicits="" public="" comment="" on="" whether="" such="" a="" national="" regulation="" is="" appropriate,="" whether="" such="" a="" requirement="" should="" be="" at="" state="" discretion="" only,="" what="" costs="" would="" be="" incurred="" by="" systems="" under="" such="" a="" regulation,="" and="" under="" what="" conditions="" a="" waiver="" from="" this="" rule="" would="" be="" appropriate.="" cross-connection="" control="" program.="" plumbing="" cross-connections="" are="" actual="" or="" potential="" connections="" between="" a="" potable="" and="" non-potable="" water="" supply="" (epa,="" 1989b).="" according="" to="" craun="" (1991),="" 24%="" of="" the="" waterborne="" disease="" outbreaks="" that="" occurred="" during="" 1981-1990="" were="" caused="" by="" water="" contamination="" in="" the="" distribution="" system,="" primarily="" as="" the="" result="" of="" cross-connections="" and="" main="" repairs.="" during="" this="" period,="" 11="" reported="" outbreaks="" with="" 1350="" associated="" cases="" were="" blamed="" on="" cross-connection="" problems="" in="" community="" water="" systems="" (craun,="" 1994).="" while="" the="" vast="" majority="" of="" outbreaks="" associated="" with="" cross="" connections="" are="" caused="" by="" pathogens,="" a="" few="" are="" caused="" by="" chemicals.="" epa="" does="" not="" have="" a="" regulation="" mandating="" a="" cross-connection="" control="" program,="" but="" does="" address="" the="" issue="" in="" the="" tcr.="" section="" 141.63(d)(3),="" for="" example,="" identifies="" proper="" maintenance="" of="" the="" distribution="" system="" as="" one="" of="" the="" best="" technologies,="" treatment="" techniques,="" and="" other="" means="" for="" achieving="" compliance="" with="" the="" mcl="" for="" total="" coliforms.="" in="" a="" subsequent="" clarification,="" epa="" explained="" that="" this="" statement="" in="" the="" rule="" includes="" a="" cross-connection="" control="" program.="" in="" addition,="" in="" a="" rule="" that="" stayed="" the="" no="" variances="" provision="" of="" the="" tcr,="" i.e.,="" allows="" states="" to="" grant="" variances,="" epa="" recommended="" that="" one="" of="" the="" criteria="" that="" states="" could="" use="" to="" identify="" systems="" that="" could="" operate="" under="" a="" variance="" without="" posing="" an="" unreasonable="" risk="" to="" health="" was="" that="" the="" system="" has="" a="" cross-connection="" control="" program="" acceptable="" to="" the="" state="" and="" performs="" an="" audit="" of="" its="" effectiveness="" (56="" fr="" 1556,="" january="" 15,="" 1991).="" the="" awwa="" also="" has="" a="" policy="" statement="" on="" cross="" connections="" urging="" systems="" to="" set="" up="" a="" program="" for="" their="" control="" (awwa,="" 1993).="" epa="" is="" seeking="" public="" comment="" on="" whether="" epa="" should="" require="" states="" and/or="" systems="" to="" have="" a="" cross-connection="" control="" program;="" what="" specific="" criteria,="" if="" any,="" should="" be="" included="" therein;="" and="" how="" often="" such="" a="" program="" should="" be="" evaluated.="" should="" epa="" require="" that="" only="" those="" connections="" identified="" as="" a="" cross="" connection="" by="" the="" public="" water="" system="" or="" the="" state="" be="" subject="" to="" a="" cross="" connection="" program?="" epa="" also="" seeks="" comment="" on="" what="" conditions="" would="" a="" waiver="" from="" this="" rule="" be="" appropriate.="" in="" addition,="" the="" agency="" requests="" commenters="" to="" identify="" other="" regulatory="" measures="" epa="" should="" consider="" to="" prevent="" the="" contamination="" of="" drinking="" water="" already="" in="" the="" distribution="" system="" (e.g.,="" minimum="" pressure="" requirements="" in="" the="" distribution="" system).="" state="" notification="" of="" high="" turbidity="" levels.="" the="" swtr="" requires="" filtered="" systems="" to="" report="" turbidity="" measurements="" to="" the="" state="" within="" ten="" days="" after="" the="" end="" of="" each="" month="" the="" system="" serves="" water="" to="" the="" public="" (sec.="" 141.75(b)(1)).="" if="" at="" any="" time="" the="" turbidity="" exceeds="" 5="" ntu,="" however,="" the="" system="" must="" notify="" the="" state="" as="" soon="" as="" possible,="" but="" no="" later="" than="" the="" end="" of="" the="" next="" business="" day="" (sec.="" 141.75(b)(3)(ii)).="" in="" addition,="" the="" system="" must="" notify="" the="" public="" as="" soon="" as="" possible,="" but="" in="" no="" case="" later="" than="" 14="" days="" after="" the="" violation="" (non-acute="" violation,="" sec.="" 141.32(a)="" and="" sec.="" 141.32(b)(10)).="" epa="" is="" considering="" broadening="" the="" requirement="" for="" systems="" to="" notify="" the="" state="" as="" soon="" as="" possible.="" the="" agency="" might,="" for="" example,="" require="" systems="" to="" notify="" the="" state="" as="" soon="" as="" possible="" if="" at="" any="" point="" during="" the="" month="" it="" becomes="" apparent="" that="" a="" system="" will="" exceed="" the="" monthly="" turbidity="" performance="" standard="" in="" sec.="" 141.73="" (0.5="" ntu="" for="" conventional="" filtration="" or="" direct="" filtration,="" 1="" ntu="" for="" slow="" sand="" filtration="" or="" diatomaceous="" earth)="" for="" an="" extended="" period="" of="" time="" (e.g.,="" more="" than="" 12="" consecutive="" hours),="" regardless="" of="" whether="" the="" system="" will="" violate="" the="" monthly="" standard.="" in="" addition,="" the="" agency="" might="" require="" systems="" to="" notify="" the="" state="" as="" soon="" as="" possible="" if="" at="" any="" point="" during="" the="" month="" it="" becomes="" apparent="" that="" a="" system="" will="" violate="" the="" monthly="" turbidity="" performance="" standard="" in="" sec.="" 141.73,="" rather="" than="" await="" the="" end="" of="" the="" month,="" as="" specified="" in="" the="" existing="" swtr.="" there="" are="" sound="" public="" health="" reasons="" for="" requiring="" swift="" state="" notification="" for="" persistent="" turbidity="" levels="" above="" the="" performance="" standards="" in="" sec.="" 141.73.="" pathogens="" may="" accompany="" the="" turbidity="" particles="" that="" exit="" the="" filters,="" especially="" with="" poor="" quality="" source="" waters.="" high="" turbidity="" levels="" in="" the="" filtered="" water,="" even="" for="" a="" limited="" time,="" may="" represent="" a="" significant="" risk="" to="" the="" public.="" increasing="" the="" disinfection="" residual="" in="" such="" cases="" is="" essential,="" but="" some="" pathogens="" (e.g.,="" giardia="" and="" cryptosporidium)="" are="" relatively="" resistant="" to="" disinfection.="" early="" notification="" would="" allow="" the="" states="" to="" require="" the="" system="" to="" issue="" an="" immediate="" public="" notice="" of="" the="" turbidity="" violation="" if="" the="" nature="" of="" the="" violation="" is="" considered="" to="" be="" an="" immediate="" health="" concern.="" epa="" solicits="" comment="" on="" whether="" the="" agency="" should="" require="" systems="" to="" notify="" the="" state="" as="" soon="" as="" possible="" for="" persistent="" turbidity="" levels="" above="" the="" performance="" standards="" or="" for="" any="" other="" situation="" that="" is="" not="" now="" a="" violation="" of="" the="" turbidity="" standards.="" e.="" alternative="" treatment="" requirements="" this="" section="" proposes="" five="" alternative="" treatment="" requirements="" for="" removing="" giardia,="" cryptosporidium,="" and/or="" viruses.="" the="" final="" rule="" might="" include="" one="" or="" some="" combination="" of="" these="" alternatives.="" these="" regulatory="" alternatives="" would="" require="" systems="" to="" remove="" a="" specified="" level="" of="" pathogen="" based="" upon="" its="" density="" in="" the="" raw="" water,="" as="" measured="" either="" under="" the="" icr="" or="" another="" comparable="" approach.="" the="" greater="" the="" pathogen="" density="" in="" raw="" water,="" the="" greater="" would="" be="" the="" pathogen="" reduction="" required="" by="" treatment.="" this="" section="" also="" examines="" several="" statistical="" options="" for="" defining="" pathogen="" densities="" in="" source="" waters.="" the="" regulatory="" impact="" analysis="" for="" this="" proposal="" includes="" preliminary="" estimates="" of="" the="" incremental="" costs="" for="" several="" of="" these="" options="" and="" discusses="" what="" incremental="" risk="" reductions="" would="" be="" needed="" to="" offset="" these="" costs="" from="" a="" cost="" benefit="" perspective.="" as="" the="" icr="" data="" become="" available,="" epa="" intends="" to="" develop="" the="" risk="" reduction="" and="" cost="" estimates="" of="" these="" different="" options="" for="" defining="" pathogen="" densities="" in="" source="" waters,="" for="" different="" treatment="" alternatives,="" and="" to="" publish="" this="" analysis="" in="" a="" notice="" of="" availability.="" after="" reviewing="" public="" comments="" and="" additional="" information="" and="" data,="" epa="" intends="" to="" select="" one="" or="" more="" options="" that="" provides="" the="" greatest="" improvement="" in="" public="" health="" taking="" into="" account="" any="" adverse="" health="" effects="" associated="" with="" treatment="" strategies="" required="" and="" the="" costs="" of="" these="" improvements.="" 1.="" options="" for="" defining="" pathogen="" densities="" in="" source="" waters="" epa="" is="" considering="" several="" options="" for="" defining="" the="" raw="" water="" pathogen="" density="" that="" systems="" would="" use="" to="" determine="" their="" needed="" level="" of="" treatment.="" as="" part="" of="" this,="" epa="" is="" considering="" both="" the="" technical="" and="" public="" health="" implications="" of="" these="" options.="" the="" public="" health="" risk="" from="" waterborne="" microorganisms="" depends="" on="" their="" density="" in="" source="" water="" and="" their="" infectious="" dose="" levels.="" since="" the="" calculated="" infectious="" dose="" levels="" for="" giardia="" and="" other="" pathogens="" do="" not="" address="" high-risk="" populations,="" e.g.,="" the="" very="" young="" and="" old="" and="" immunocompromised="" individuals,="" they="" may="" not="" be="" conservative="" with="" respect="" to="" protecting="" public="" health.="" therefore,="" epa="" could="" provide="" a="" margin="" of="" safety="" for="" such="" populations="" by="" requiring="" a="" system="" to="" define="" the="" pathogen="" density="" used="" for="" determining="" the="" required="" treatment="" level="" in="" terms="" of="" a="" conservative="" statistical="" method,="" i.e.,="" one="" that="" would="" provide="" a="" higher="" pathogen="" density="" than="" an="" arithmetic="" mean.="" such="" analysis="" would="" also="" need="" to="" consider="" various="" assumptions="" regarding="" the="" likelihood="" of="" a="" detected="" organism="" being="" viable="" and="" infectious.="" currently="" it="" is="" not="" yet="" possible="" to="" determine="" whether="" a="" protozoan="" cyst="" in="" water="" is="" viable="" or,="" if="" viable,="" infectious.="" epa="" and="" other="" groups,="" however,="" are="" conducting="" research="" in="" this="" area.="" the="" approach="" epa="" selects="" for="" calculating="" pathogen="" density="" should="" consider="" the="" wide="" temporal="" and="" spatial="" variations="" in="" densities="" that="" occur="" in="" raw="" water="" and="" should="" be="" appropriate="" for="" the="" calculation="" of="" the="" attendant="" health="" risks.="" among="" the="" approaches="" being="" considered="" by="" the="" agency="" are="" the="" arithmetic="" mean,="" geometric="" mean,="" 90th="" percentile,="" and="" maximum="" measured="" value.="" these="" are="" discussed="" below.="" epa="" expects="" that="" systems="" subject="" to="" this="" rule="" will="" use="" their="" data="" collected="" under="" the="" icr="" as="" a="" basis="" for="" determining="" source="" water="" pathogen="" densities="" and="" selection="" of="" appropriate="" treatment="" levels.="" the="" negotiating="" committee="" recommended="" this="" approach="" so="" that="" systems="" would="" have="" sufficient="" time="" to="" determine="" the="" need="" for,="" design,="" and="" install="" any="" necessary="" treatment="" to="" comply="" with="" both="" the="" eswtr="" and="" d/dbpr="" requirements="" in="" a="" consistent,="" integrated="" manner.="" this="" approach="" would="" require="" states,="" as="" part="" of="" their="" primacy="" applications="" for="" the="" eswtr,="" to="" include="" provisions="" for="" acquiring="" icr="" data="" from="" epa's="" icr="" data="" base="" when="" it="" becomes="" available,="" directly="" from="" the="" system="" or="" a="" database.="" epa="" recognizes="" that="" some="" systems="" that="" currently="" serve="" fewer="" than="" 10,000="" people,="" and="" thus="" not="" subject="" to="" icr="" monitoring,="" may="" eventually,="" as="" a="" result="" of="" their="" growth,="" become="" subject="" to="" the="" interim="" eswtr.="" once="" such="" a="" system="" serves="" 10,000="" people="" or="" more,="" the="" rule="" would="" require="" it="" to="" collect="" data="" sufficient="" to="" determine="" the="" source="" water="" pathogen="" densities="" in="" a="" manner="" analogous="" to="" that="" specified="" in="" the="" icr.="" the="" system="" would="" then="" use="" these="" data="" to="" determine="" the="" level="" of="" treatment="" needed.="" epa="" solicits="" comment="" on="" this="" approach.="" a.="" use="" of="" arithmetic="" mean="" of="" data.="" the="" arithmetic="" mean="" is="" the="" sum="" of="" the="" pathogen="" densities="" from="" all="" collected="" samples="" divided="" by="" the="" number="" of="" samples.="" an="" arithmetic="" mean="" would="" be="" calculated="" for="" each="" pathogen.="" the="" arithmetic="" mean="" is="" most="" appropriate="" when="" the="" densities="" are="" relatively="" uniform,="" both="" spatially="" and="" temporally,="" and="" symmetrical="" about="" the="" mean.="" use="" of="" the="" arithmetic="" mean="" is="" most="" useful="" when="" the="" distribution="" of="" measured="" values="" approximates="" a="" normal="" distribution.="" relative="" to="" the="" geometric="" mean,="" the="" arithmetic="" mean="" allows="" an="" easier="" calculation="" of="" confidence="" intervals="" and="" may="" be="" more="" conservative.="" when="" considering="" the="" multiple="" exposures="" associated="" with="" drinking="" water="" ingestion="" at="" the="" low="" microbial="" risk="" levels="" associated="" with="" treated="" water,="" risks="" can="" be="" considered="" as="" additive="" and="" linearly="" related.="" under="" these="" circumstances,="" the="" arithmetic="" mean="" is="" superior="" to="" the="" geometric="" mean="" in="" the="" estimation="" of="" central="" tendency="" (regli="" et="" al.,="" 1991).="" b.="" use="" of="" geometric="" mean="" of="" data.="" the="" geometric="" mean="" is="" defined="" by="" the="" equation:="">m=log-1 (1/n x [log X1+log X2+...log Xn]),
Where n = number of samples and Xi is the measured density for
each sample. For example, the geometric mean of the values 1, 10, and
100 would be 10. The geometric mean is more appropriate than the
arithmetic mean for representing the central tendency for data that
have a skewed distribution. However, the geometric mean is less
conservative, i.e., it would generally estimate a lower mean density
and therefore lower risk for pathogens than the arithmetic mean (for
example, the arithmetic mean of 1, 10, and 100 is 37, versus the
geometric mean of 10). Nevertheless, depending upon the assumptions
made in the risk assessment calculation (e.g., percentage of cysts/
oocysts viable), use of the geometric mean may be adequately
conservative for estimating exposures and consequently appropriate
levels of treatment (Regli et al., 1991).
c. Use of the 90th percentile value. Another alternative for
defining pathogen density is to base this value on the 90th percentile
of all data for a particular pathogen. This is the value below which
fall 90% of the data points and above which fall 10% of the data
points. This approach is more conservative in terms of risk than the
arithmetic mean and geometric mean, because for sources where pathogen
density varies significantly throughout the year, use of this value
will be more representative of the elevated risk associated with peak
contamination periods.
Use of the 90th percentile measured value, however, has the obvious
drawback that it requires a sufficient number of samples to provide a
good 90th percentile estimate without interpolation. In many cases,
particularly for small water systems, cost considerations will prevent
extensive sampling. For example, the proposed ICR would require only
six raw water samples over the period of a year for systems from 10,000
to 100,000 people served. The 90th percentile value could be
interpolated from the two highest values.
d. Use of the maximum measured value. This approach would dictate
the use of the highest density measured under the ICR for raw water.
Since few systems have the resources for routine, frequent, and long-
term sampling for pathogens such as Giardia, Cryptosporidium and
viruses, it is clear that episodic periods of microbial contamination
may escape detection. EPA is particularly concerned with the risks from
unusually high level contamination events that might exceed the
removal/inactivation capacity of a treatment system. While the maximum
measured value may not be representative of the normal pathogen density
in a source water, it would be more indicative of potential short-term
risks.
Additionally, since the published dose-response values for Giardia
and other pathogens were developed in healthy adult populations and
therefore are not conservative with respect to protecting public
health, EPA might select use of the maximum value, which is the most
conservative statistical option, to offset this problem. Alternatively,
it may be more appropriate to use a less conservative method for
estimating microbial densities but to use more conservative criteria
for deriving the actual level of treatment requirements as they relate
to pathogen densities. For example, if EPA assumes that all Giardia
cysts detected are viable and infectious to humans in specifying the
level of treatment needed, this approach may be sufficiently
conservative to warrant the density calculation by one of the other
above described methods.
A major problem with basing the density calculation on the maximum
value is that if a utility collects more than the minimum number of
samples required in the interest of better defining potential
exposures, it has a greater likelihood of collecting a sample with a
higher pathogen density than would occur with the minimum required
number of samples. In this case, the system may face a more stringent
(and thus more expensive) standard.
Use of the maximum measured density may be more appropriate than
other statistical methods for systems that have not collected
sufficient data to allow calculation of an adequately representative
mean value or 90th percentile value. With such limited data, the
maximum value might be suitable for determining level of treatment.
EPA is soliciting comment on which approach is most appropriate for
defining pathogen density. The Agency is also requesting comment on
whether the approach used should be based on the number of pathogen
samples collected, i.e., the maximum measured value would be required
for systems taking only six samples under the ICR (systems serving
between 10,000 and 100,000 people) and 90th percentile value for
systems that collect at least 10 samples.
2. Treatment alternatives for controlling pathogens. To determine
what regulatory controls are most appropriate for controlling pathogens
in drinking water, EPA must decide what constitutes acceptably safe
drinking water. The SDWA frames this discussion in determining MCLGs
and MCLs. MCLG levels, which are not legally enforceable, are based
solely on health concerns. As required by the SDWA, they are set ``at
the level at which no known or anticipated adverse effects on the
health of persons occur and which allows an adequate margin of
safety''. The corresponding enforceable regulation consists of either
an MCL set as close to the MCLG as feasible, taking cost and
availability of treatment into account; or, when it is not
technologically or economically feasible to monitor for the
contaminants, a treatment technique(s) to achieve an acceptable risk.
The SWTR promulgated an MCLG for Giardia of zero, i.e., no Giardia
cysts should be allowed in drinking water. A system using surface water
cannot usually attain this goal in any practical sense. Therefore, the
SWTR preamble suggested a more practical health goal for Giardia:
drinking water should not cause more than one Giardia lamblia infection
annually per 10,000 exposed persons (10-4 risk). In contrast to
this goal, EPA policy for specific chemical carcinogens is for
theoretical lifetime upper bound risks to be no greater than within a
range of 10-4 to 10-6. For non-carcinogenic chemical
contaminants, EPA policy is to base the MCLG on the reference dose
(RfD) for the given chemical. The RfD is calculated to be below any
known level of exposure resulting in adverse health effects, so that
drinking water at the resulting MCLG over a lifetime should be without
known risk.
In developing the D/DBP rule (proposed elsewhere in today's Federal
Register), EPA is attempting to ensure that drinking water remains
microbiologically safe at the limits set for disinfectants and
byproducts, and that the disinfectants and byproducts themselves do not
pose an unacceptable risk at these limits.
Based on data on microbial illness and death in the U.S. compiled
by Bennett et al. (1987), the estimated annual risk of waterborne
illness during 1985 was about 4 x 10-3 and the estimated lifetime
risk of death was about 3 x 10-4. As stated above, the goal of the
SWTR was for systems to achieve a risk of less than 10-4
infections per year for Giardia. Because Giardia is relatively
difficult to inactivate compared to virus and bacterial pathogens, the
SWTR assumed that water treatment adequate to achieve a 10-4 risk
for Giardia would provide an even higher level of protection against
pathogenic viruses and bacteria in untreated surface waters. Applying
the Bennett et al. (1987) data regarding the ratio of mortality to
waterborne illness (0.1 percent = 10-3), if a system achieves an
incidence of 10-4 waterborne infections per year or less, the
associated lifetime risk of death would be less than 7 x 10-6.
This is a 40-fold decrease in risk relative to those estimated by
Bennett et al. (1987), who used 1985 data.
The above calculations refer to the average individual and an
average pathogenic organism. Available dose-response data show that the
risk of infection for a given pathogen density in the consumed water
ranges over several orders of magnitude for different organisms (Regli
et al., 1991). Setting a generic microbiological drinking water
standard based on one dose-response curve will either overestimate or
underestimate risks from other organisms. The risk of death from
infection likewise varies widely with the organism (Bennett et al.,
1987). Therefore, the severity of the illness associated with a given
organism must be considered.
Additional considerations in assessing acceptable waterborne
microbial risks involve the human subpopulations sensitive to
infection, illness and death. Infection does not always result in
illness; many infections are asymptomatic (Rendtorff, 1954; Lopez et
al., 1980). The progression and severity of illness following microbial
infection are more a function of individual physiology than the
magnitude of dose, as is true for many toxic chemicals. Acute
gastrointestinal illness, the most common microbial illness, is
generally considered non-life threatening in normally healthy adults.
However, this is not necessarily true for those subpopulations that are
more sensitive to microbial infection or illness. Some studies (Glass
et al., 1991; Lew et al., 1991) indicate that infants and those over 70
years old have mortalities of 3-5 percent from diarrhea requiring
hospitalization. As discussed above, Cryptosporidium infections, mild
in healthy persons, are sometimes fatal to the immuno-compromised.
Other identified sensitive human subpopulations include pregnant women
and those with cardiovascular disease. EPA estimates that about 15% of
the U.S. population is in these higher risk groups.
Prudent health policy would be to protect these groups from their
higher risks of waterborne microbial infection. Use of a one percent
mortality-to-illness rate (instead of a 0.1 percent) to represent more
deadly organisms and a 10-fold uncertainty factor (as used in EPA's RfD
calculations) to account for these sensitive subpopulations may be
appropriate for estimating potential risks resulting from systems
achieving regulatory goals. A risk calculation based on this approach,
assuming that the system achieves the risk goal of 10-4 annual
infections for the average population, might result in a 7 x 10-5
(i.e., 10-4 x 10-2 x 70 years) lifetime risk of death for
certain subpopulations. The 7 x 10-5 lifetime risk of death (which
is a more severe endpoint than cancer) is barely within the 10-4-
10-6 guideline for excess lifetime cancer risk that EPA uses for
regulating chemical carcinogens in drinking water.
These calculations, while based on estimates and approximations and
having large uncertainties, suggest that the risk level of 10-4
annual infections may be acceptable, albeit barely so. If EPA were to
accept a more stringent annual risk level of 10-5 or 10-6
infections to achieve a greater consistency between lifetime mortality
risks from waterborne pathogens and most regulated drinking water
chemicals, substantial increases in treatment might be required. EPA
solicits comment on the appropriateness and magnitude of specific
acceptable risk levels for microbial infection and illness.
To counter waterborne illness, EPA is proposing five treatment
alternatives for controlling Giardia, Cryptosporidium, and/or viruses.
Within each alternative, several options are addressed. The Agency may
promulgate one or more of these alternatives. Alternative A addresses
enhanced treatment for Giardia only. Alternatives B and C address
treatment for Cryptosporidium only. Alternative D addresses enhanced
treatment for viruses only. Alternative E maintains existing level of
treatment requirements for Giardia and viruses. EPA requests comment on
what alternative(s) is most suitable.
a. Alternative A. Enhanced treatment for Giardia. This alternative
bases the extent of treatment required on the Giardia density in the
source water. The SWTR currently requires a 99.9 percent (3-log)
removal/inactivation of Giardia for all surface waters, regardless of
Giardia cyst concentration in the source water. As discussed above and
in the SWTR, EPA believes that for source waters of high quality (low
pathogen densities), this level of treatment should result in less than
one case of giardiasis (and most other waterborne disease) per 10,000
people per year. This risk level for Giardia is associated with an
infectious Giardia cyst density in the source water of less than one
cyst/100 liters and assumes that 3 logs of removal/inactivation is
consistently achieved on such source water. For more information about
Giardia risk calculations and associated uncertainties and assumptions,
refer to Rose et al. (1991), Regli et al. (1991), and Macler and Regli
(1993).
Under Alternative A, systems using source waters with higher
Giardia densities would be required to meet higher levels of treatment
to satisfy the desired acceptable risk level, e.g., the annual
10-4 risk or perhaps a more stringent goal. Specifically, under
one option of alternative A, EPA is proposing that systems meet the
level of treatment for Giardia associated with the following Giardia
concentrations in the source water to achieve a 10-4 annual risk
level:
------------------------------------------------------------------------
Required treatment
No. of giardia/100L level (percent)
------------------------------------------------------------------------
<1............................................... 99.9="" (3-log).="" 1-9..............................................="" 99.99="" (4-log).="" 10-99............................................="" 99.999="" (5-log).="">99.............................................. 99.9999 (6-log).
------------------------------------------------------------------------
The determination by utilities and States of removal and
inactivation efficiencies for specific treatment strategies would be
based on EPA guidance and information, as is currently done under the
existing SWTR. EPA would revise the existing SWTR Guidance Manual based
on data collected under the ICR and research to complement any criteria
promulgated under the ESWTR. The Agency expects that data collected
under the ICR will be used by States and utilities to define the source
water concentration and consequently the appropriate level of treatment
for individual systems. If a utility has not collected data on pathogen
densities in source water under the ICR, it would be required to do so
to define the appropriate level of treatment.
Depending on the method used for calculating pathogen density,
assumptions used for estimating risk (e.g., whether to assume that all
or only a portion of the detected cysts in the source water are viable
and infectious to humans), the desired acceptable risk level, concern
about DBP risk, and the technical and economic feasibility of achieving
different levels of treatment, it may be appropriate to specify
treatment requirements that address higher source water pathogen
concentrations than described above. EPA is not aware to what extent
physical removal greater than 2.5 logs can reasonably be achieved by
systems using conventional water treatment approaches commonly
practiced in the United States. The Agency believes that systems that
optimize their treatment may be able to achieve substantially higher
levels of removal. Membrane filtration techniques, although promising
for much higher levels of removal, may not yet be technologically or
economically feasible for large numbers of systems. The balance of the
removal/inactivation requirement may have to rely on the use of
chemical disinfectants. However, while EPA has confidence in the use of
disinfectants to achieve current SWTR requirements, it has not been
demonstrated that CT values extrapolated from tables in the SWTR or
other sources are valid for higher levels of disinfection (e.g., to
achieve a 4- or 5-log reduction of Giardia). EPA requests comment on
approaches to achieve higher levels of treatment by physical means and
on the use of existing CT values in the EPA guidance (EPA, 1991) to
predict, by extrapolation, higher levels of inactivation that could be
achieved by disinfection.
EPA is considering an alternative version of the above described
treatment requirements that would instead require greater Giardia
reductions for source waters beginning with Giardia concentrations of
10 or more cysts/100 liters, as indicated below:
------------------------------------------------------------------------
Required treatment
No. giardia/100L level (percent)
------------------------------------------------------------------------
10-99............................................ 99.99 (4-log).
100-999.......................................... 99.999 (5-log).
>1000............................................ 99.9999 (6-log).
------------------------------------------------------------------------
EPA solicits comment on the two treatment options described above
and on associated variations.
b. Alternative B. Specific treatment for Cryptosporidium. EPA is
proposing a treatment technique rather than an MCL for Cryptosporidium,
because EPA believes that it is not currently economically or
technologically feasible for a system to monitor for this organism in
the finished water to determine whether it meets an acceptable risk
level. The Agency bases its belief on three factors: (1) The
variability of Cryptosporidium spatially and temporally may be
considerable, and consequently systems would have to collect frequent
samples and inordinately large sample volumes to properly characterize
the density of this organism, (2) current methods for Cryptosporidium
analysis are difficult and expensive, (3) it is not yet possible to
predict the risk resulting from a specific level of exposure to
Cryptosporidium, and (4) even if Cryptosporidium could be detected at
the lowest concentrations of concern in the finished water, the
exposure and associated risk would have already occurred, thereby
reducing the significance of monitoring non-compliance.
Under this rule, all community and non-community public water
systems using any surface water source, or groundwater under the direct
influence of surface water, would be required to treat these sources as
described below. EPA anticipates that human dose-response data for
Cryptosporidium will be available within the next year and will include
these data in a Notice of Availability, probably in March 1996. Because
they are not yet available, basing the treatment level on a specific
acceptable risk level, as proposed by EPA for Giardia, cannot be used
for Cryptosporidium in the present notice. Data collected to date
suggest that the dose-response for Cryptosporidium may be similar to
that for Giardia. If this is true, then the required reduction level
for Cryptosporidium may be the same as for Giardia to achieve an
equivalent risk level for similar source water densities.
In the absence of dose-response data, EPA is proposing a wide
variety of options. One sub-alternative would be to base the level of
treatment on the Cryptosporidium densities found in the source water,
as presented in the Table below.
------------------------------------------------------------------------
Required treatment
No. cryptosporidium/100L level (percent)
------------------------------------------------------------------------
<1............................................... 99.9="" (3-log).="" 1-9..............................................="" 99.99="" (4-log).="" 10-99............................................="" 99.999="" (5-log).="">99.............................................. 99.9999 (6-log).
------------------------------------------------------------------------
EPA is concerned, however, that it may not be technologically or
economically feasible to achieve the treatment levels above, given that
Cryptosporidium is much more resistant to disinfection than is Giardia.
Conventional treatment of coagulation, sedimentation and filtration may
not reliably achieve more than 2.5-log or 3-log Cryptosporidium oocyst
reduction under typical operating conditions. While membrane filtration
technologies (ultrafiltration, nanofiltration), possibly following
conventional treatment processes, appear to promise considerably
greater reductions in Cryptosporidium densities, their widespread use
for this purpose raises other concerns such as waste disposal of the
concentrate, water wastage, potential failure of the membrane, and
significant costs. Unless systems can feasibly achieve higher removal
levels for Cryptosporidium by physical means, they would have to
achieve this additional reduction by the use of disinfectants. However,
uncertainties exist with respect to disinfection of Cryptosporidium.
Current data suggests that chlorine and chlorine-based disinfectants
are relatively ineffective in inactivating Cryptosporidium, and the
Agency is not certain if alternative disinfectants, such as ozone, are
more effective than chlorine to allow systems to comply with the
removal/inactivation levels above.
With this in mind, EPA is also considering two other treatment sub-
alternatives for Cryptosporidium, as follows:
------------------------------------------------------------------------
Required treatment
No. cryptosporidium/100L level (percent)
------------------------------------------------------------------------
<1............................................... 99="" (2-log).="" 1-9..............................................="" 99.9="" (3-log).="" 10-99............................................="" 99.99="" (4-log).="">99.............................................. 99.999 (5-log).
------------------------------------------------------------------------
------------------------------------------------------------------------
Required treatment
No. cryptosporidium/100L level (percent)
------------------------------------------------------------------------
<10.............................................. 99="" (2-log).="" 10-99............................................="" 99.9="" (3-log).="">99.............................................. 99.99 (4-log).
------------------------------------------------------------------------
EPA requests comment on all treatment alternatives discussed above
for Cryptosporidium.
c. Alternative C. 99% (2-log) removal of Cryptosporidium. Under
this alternative, EPA would require systems to achieve at least 99% (2-
log) removal of Cryptosporidium by filtration (with pretreatment)
alone. This alternative is based on the premise that the 3-log removal/
inactivation requirement specified for Giardia is not economically or
technologically feasible for Cryptosporidium, since laboratory data
suggests that Cryptosporidium is considerably more resistant to
disinfection than is Giardia. In addition, it may not be practical to
remove more than two logs of Cryptosporidium consistently by
clarification and filtration processes. EPA believes, however, that a
two-log removal of Cryptosporidium is feasible using current
conventional treatment methods of coagulation, sedimentation and
filtration, as specified under the SWTR.
Under this treatment option, EPA would continue to assess new field
and laboratory data to control Cryptosporidium by physical removal and
disinfection. If these data indicate that proportionally higher levels
of Cryptosporidium removal/inactivation can be achieved at a reasonable
cost, then EPA would revise the ESWTR accordingly as part of the long-
term ESWTR regulatory development. The Agency would also revise the
SWTR Guidance Manual to suggest approaches for improving system design
and operations for controlling Cryptosporidium. When sufficient human
dose-response information for Cryptosporidium becomes available to
allow calculation of drinking water health risks from this organism,
EPA will consider a risk-based approach to establishing adequate
treatment levels.
EPA solicits comment on whether a higher minimum removal
requirement than two logs should be specified for Cryptosporidium under
this alternative. The Agency also requests comment on whether the
removal requirement should be increased if treatment were to include
disinfection.
d. Alternative D. Specific disinfection treatment for viruses. The
SWTR required systems to achieve a four-log reduction/ inactivation of
viruses. This is to be achieved through a combination of filtration and
disinfection or, for systems not required to filter their source
waters, by disinfection alone. Viruses are of particular concern, given
that one or several virus particles may be infectious (Regli et al.,
1991) and that several enteric viruses are associated with relatively
high mortality rates (Bennett et al., 1987). Failure or impairment of
filtration performance could allow substantial pathogen contamination
of drinking water, particularly if the disinfection barrier following
filtration is minimal.
The SWTR considered Giardia to be a surrogate for viruses, and
assumed that if viruses were present in the source water, treatment
requirements adequate to reduce Giardia by three logs would also reduce
viruses to safe levels. This assumption may not be appropriate if a
system were to achieve a 3-log removal of Giardia by physical means and
provide little disinfection inactivation. Viruses may be present in
substantial numbers even in the absence of detectable Giardia cysts.
Treatment designed to minimize Giardia may not be optimal for
viruses. Viruses are substantially smaller than Giardia cysts or
Cryptosporidium oocysts and may pass through certain filter media that
will remove the larger protozoa. Therefore, use of data on Giardia,
Cryptosporidium, or even coliform bacteria (intermediate in size
between viruses and protozoa) in assessing treatment efficacy may not
be adequate for virus control. Studies by Payment et al. (1991) showed
that conventionally treated water meeting current Canadian microbial
drinking water advisory levels still led to substantial illness in the
studied population. These authors suggested that much of this illness
could have resulted from viral infection.
For the above reasons, particularly for strengthening the treatment
barrier by disinfection, EPA is proposing to require that systems
provide sufficient disinfection such that by disinfection alone it
would achieve at least a 0.5-log inactivation of Giardia or,
alternatively, a 4-log inactivation of viruses. This requirement would
be independent of the level of physical removal, e.g., if filtration
was able to remove three logs of Giardia, the system would still have
to provide at least an additional 0.5-log inactivation of Giardia or 4-
log inactivation of viruses by disinfection. Therefore, this would mean
that the system would provide 6 logs of virus removal/inactivation,
assuming it is removing 2-logs of viruses by filtration alone. EPA
would provide guidance to indicate the appropriate CT values to use
with these two alternatives.
The SWTR assumed that a 0.5-log inactivation of Giardia would
result in a 4-log inactivation of viruses. This assumption was based on
a study where the effect of free chlorine on the hepatitis A virus was
examined (Sobsey, 1991). Subsequent investigations, however, have
suggested that some viruses, such as the Norwalk agent, are
substantially more resistant to disinfection by chlorine than is the
hepatitis A agent. Additionally, use of disinfectants other than free
chlorine to achieve the 0.5-log inactivation of Giardia may not yield a
4-log inactivation of viruses. Therefore, a requirement to provide
sufficient disinfection to inactivate 4 logs of viruses may be more
conservative than the alternative requirement of providing sufficient
disinfection to inactivate 0.5 logs of Giardia.
Either of these two approaches could result in several additional
logs of pathogen removal/inactivation for systems that practice
conventional treatment. For example, where the system can remove by
physical means at least 2-logs of viruses, the disinfection requirement
would yield a total 6-log removal/inactivation of viruses (i.e, 2 logs
by physical means and 4 logs by disinfection).
e. Alternative E. No change to existing SWTR treatment requirements
for Giardia and viruses. Under this alternative, the existing SWTR
requirements for treatment for Giardia and viruses would not change.
For Cryptosporidium control, EPA could either regulate this organism
directly (e.g., Alternative C above) or make a finding that
Cryptosporidium is adequately controlled by filtration and disinfection
requirements in the existing SWTR. The Agency may choose this
alternative to allow the Agency time to fully develop analyses of the
ICR data and accumulate additional data on pathogen occurrence,
treatment performance, and health effects, given the view that the
current SWTR has not been in effect long enough to evaluate the
projected improvements in drinking water quality and resulting public
health benefits. EPA would consider additional regulatory alternatives
while developing the long-term ESWTR, based on this new data. The
Agency requests comment on this alternative, as well.
IV. State Implementation
This section describes the regulations and other procedures and
policies States would have to adopt, or have in place, to implement the
rule proposed today. States must continue to meet all other conditions
of primacy in 40 CFR Part 142.
Section 1413 of the SDWA establishes requirements that a State must
meet to maintain primary enforcement responsibility (primacy) for its
public water systems. These include (1) adopting drinking water
regulations that are no less stringent than Federal NPDWRs in effect
under sections 1412(a) and 1412(b) of the Act, (2) adopting and
implementing adequate procedures for enforcement, (3) keeping records
and making reports available on its activities that EPA requires by
regulation, (4) issuing variances and exemptions (if allowed by the
State) under conditions no less stringent than allowed by sections 1415
and 1416, and (5) adopting and being capable of implementing an
adequate plan for the provision of safe drinking water under emergency
situations.
40 CFR Part 142 sets out the specific program implementation
requirements for States to obtain primacy for the public water supply
supervision (PWSS) program, as authorized under section 1413 of the
Act. In addition to adopting the basic primacy requirements, States may
be required to adopt special primacy provisions pertaining to a
specific regulation. These regulation-specific provisions may be
necessary where implementation of the NPDWR involves activities beyond
those in the generic rule. States are required by 40 CFR 142.12 to
include these regulation-specific provisions in an application for
approval of their program revisions. These State primacy requirements
would apply to the rule proposed today, along with the special primacy
requirements discussed below.
To implement today's proposed rule, States would be required to
adopt revisions to Sec. 141.2, Definitions; Sec. 141.52, Maximum
contaminant level goals for microbiological contaminants; Sec. 141.70,
General requirements; Sec. 141.71, Criteria for avoiding filtration;
and Sec. 141.74, Analytical and monitoring requirements.
A. Special State Primacy Requirements
In addition to adopting drinking water regulations at least as
stringent as the Federal regulations listed above, EPA would require
that States adopt certain additional provisions related to this
regulation to have their program revision application approved by EPA.
Because this rule would provide considerable State latitude on
implementation, today's rule would require a State to include, as part
of its State program submission, its implementation policies and
procedures. This information would advise the regulated community of
State requirements and help EPA in its oversight of State programs. In
concert with promulgating the interim ESWTR, EPA would revise the SWTR
Guidance Manual (EPA, 1991). This guidance would assist States in
developing appropriate criteria in the regulations they adopted.
To ensure that the State program includes all the elements
necessary for a complete enforcement program, today's notice proposes
that to obtain EPA approval for implementing this rule, the State's
application would be required to include the following:
(1) Adoption of the promulgated ESWTR.
(2) Description of the protocol the State will use to judge the
adequacy of watershed protection programs for minimizing the potential
for contamination by Giardia cysts, Cryptosporidium oocysts, and
viruses in the source water. The SWTR required States to specify the
methodology they would use to judge the adequacy of a watershed control
program to control the presence of waterborne Giardia. This rule would
add Cryptosporidium. The addition of Cryptosporidium is significant
because it may prohibit or substantially limit certain watershed uses
such as cattle farming and feedlots. The location of cattle feedlots on
a watershed would require additional control measures.
(3) Description of the criteria and methods the State will use for
the conduct and review of sanitary surveys. If the State elects to
allow non-State personnel to conduct the surveys, the State must
specify the criteria for approval and oversight of these personnel and
of the surveys.
(4) Description of the procedures for determining the level of
treatment required of systems to meet removal and/or inactivation
requirements under the rule. If Alternative A described in Section IIIE
above is promulgated, demonstration by the State that it has in place
enforceable design and operating criteria for achieving the levels of
Giardia removal and/or inactivation required. If either Alternative B
or C described in Section IIIE above is promulgated, demonstration by
the State that it has in place enforceable design and operating
criteria for achieving the levels of Cryptosporidium removal and/or
inactivation required. Compliance with the design and operating
criteria would be judged on a system-by-system basis.
B. State Recordkeeping Requirements
Changes to the existing recordkeeping requirements to implement the
provisions proposed in this notice would require, under general
recordkeeping requirements, States to maintain records on the level of
treatment necessary to achieve the required levels of removal and/or
inactivation of Giardia, Cryptosporidium and/or viruses. States would
also be required to maintain a record of any decisions made as a result
of sanitary surveys. These records must be kept for 40 years (as
currently required by Sec. 142.14 for other State decision records) or
until a subsequent determination is made, whichever is shorter. If the
final rule requires systems to base level of treatment on source water
pathogen densities, then the State must maintain record of these
densities.
C. State Reporting Requirements
Currently States must report to EPA information under 40 CFR 142.15
regarding violations, variances and exemptions, enforcement actions and
general operations of State public water supply programs. Today's rule
would require States to provide additional information to EPA within
the context of the existing special report requirements for the SWTR
(Sec. 142.15(c)(1)) on microbial densities in the source water and the
resulting required levels of treatment for each public water system
supplied by a surface water source or by ground water under the direct
influence of surface water.
V. Public Notice Language
The SDWA (section 1414(c)) requires that notices of violation of
the MCL or treatment requirement for a specific contaminant include
EPA-specified language on the adverse health effects of that
contaminant. Requirements for public notification are found in 40 CFR
141.32. In this notice, EPA is proposing that the existing language for
violating the treatment technique requirements in Subpart H of the
SWTR, found in 40 CFR 141.32(e)(10), not be changed. This decision is
based on EPA's belief that language is sufficiently broad to include
the adverse health effects from Cryptosporidium exposure.
VI. Economic Analysis
A. Cost of Proposed Rule
This proposed rule would result in treatment costs, monitoring
costs, and State implementation costs. These costs are difficult to
estimate because of uncertainty in the number of systems that would
have to improve treatment and the extent of that improved treatment.
This information would depend primarily on the results of future
monitoring under the ICR. Under the ICR, systems using surface water
and serving 10,000 people or more would determine raw water pathogen
densities and, in some cases, the efficiency of treatment for reducing
pathogen concentrations. Given the above uncertainties, the cost
estimates can now only be addressed in the most general way, across a
wide range of possibilities.
With regard to treatment costs, if ICR results indicate that the
existing SWTR ensures adequate levels of treatment for most systems,
then minimal additional treatment costs would be necessary. Regardless
of whether the SWTR is amended to require higher levels of treatment,
at least some systems would be expected to upgrade existing levels of
treatment based on EPA guidance and ICR monitoring results. Similarly,
some systems might reduce existing levels of disinfection upon a
finding that their source water is of better quality than expected.
Also, some costs will be incurred by systems correcting for
deficiencies identified through the sanitary survey requirement.
If ICR monitoring indicates that many source waters contain
considerably higher pathogen concentrations than anticipated under the
SWTR, then substantial national treatment costs would result in
mitigating the associated health risk. These costs could involve
increasing disinfection contact time or dosage, switching to stronger
disinfectants, or improving filtration efficiencies through upgrades or
installation of new technologies.
In estimating possible costs resulting from an ESWTR EPA assumed
that (1) national Giardia density in source waters are represented by
the survey results of LeChevallier et al. (1991a), (2) all systems are
at least meeting the treatment requirements of the existing SWTR, (3)
some systems, as indicated by the survey results of LeChevallier et al
(1991), are providing higher levels of treatment than required by the
SWTR, (4) systems would be required to provide sufficient treatment of
their source water to achieve no greater than a 10-4 annual risk
level for Giardia, based on the dose-response data and risk assessment
methodology developed by Rose et al. (1991) and Grubbs et al. (1992),
(5) additional Giardia reduction beyond the requirements of the SWTR to
achieve the 10-4 risk level would be achieved solely by using
chlorine as the disinfectant and providing additional disinfectant
contact time (i.e., increasing the CT value by increasing the contact
basin size), (6) when all ancillary construction costs including site-
specific factors are taken into account, the average total capital cost
per system is twice the capital cost of increasing the size of the
contact basin alone. Based on the assumptions of Rose et al. (1991) and
Grubbs et al. (1992), EPA calculates that systems would need a Giardia
removal/inactivation level of 3, 4, 5, or 6 logs for Giardia
concentrations in the source water of <1 cysts/100="" l,="" 1-9="" cysts/100="" l,="" 10-99="" cysts/100="" l,="" and="" 100="" cysts/100="" l="" or="" greater,="" respectively.="" national="" cost="" estimates="" for="" systems="" to="" comply="" with="" an="" interim="" eswtr="" as="" described="" above="" are="" provided="" in="" table="" vi-1.="" as="" discussed="" in="" section="" iii.b="" of="" this="" preamble,="" depending="" upon="" the="" criteria="" that="" are="" promulgated="" under="" the="" interim="" eswtr,="" epa="" also="" intends="" to="" propose="" requirements="" for="" systems="" serving="" less="" than="" 10,000="" people,="" under="" a="" long-="" term="" eswtr,="" to="" prevent="" any="" undue="" downside="" microbial="" risks="" that="" might="" otherwise="" result="" while="" systems="" of="" this="" size="" achieve="" compliance="" with="" the="" stage="" 1="" d/dbp="" rule.="" therefore,="" table="" vi-1="" also="" includes="" cost="" estimates="" for="" systems="" serving="" less="" than="" 10,000="" people,="" even="" though="" these="" costs="" are="" not="" attributed="" to="" the="" interim="" eswtr.="" table="" vi-1="" presents="" the="" additional="" contact="" basin="" costs="" needed="" for="" twelve="" system="" size="" categories="" (population="" served);="" for="" each="" size="" category,="" the="" number="" and="" type="" of="" systems="" affected="" (filtered="" without="" softening="" or="" filtered="" with="" softening),="" the="" associated="" total="" capital="" costs,="" and="" the="" associated="" total="" annualized="" costs.="" in="" this="" calculation,="" operation="" and="" maintenance="" costs="" are="" assumed="" to="" be="" negligible="" since="" systems="" are="" already="" disinfecting="" and="" most="" of="" the="" additional="" inactivation="" could="" be="" achieved="" by="" additional="" disinfectant="" contact="" time.="" details="" of="" this="" analysis="" and="" other="" assumptions="" are="" described="" in="" the="" regulatory="" impact="" analysis="" for="" the="" eswtr="" (epa,="" 1994).="" under="" this="" approach,="" epa="" estimates="" that="" the="" capital="" and="" annualized="" costs="" nationwide="" for="" systems="" serving="" at="" least="" 10,000="" people="" would="" be="" $3661="" million="" and="" $391="" million,="" respectively.="" using="" the="" same="" assumptions="" for="" systems="" serving="" fewer="" than="" 10,000="" people="" would="" result="" in="" an="" additional="" $820="" million="" capital="" costs="" and="" $114="" million="" annualized="" costs="" nationwide,="" or="" a="" total="" for="" all="" system="" sizes="" of="" $4481="" million="" in="" capital="" costs="" and="" $504="" million="" in="" annualized="" costs.="" the="">-4 annual risk level target was used as an example;
costs for achieving different acceptable risk levels, of course, will
differ considerably. Although other treatment measures could be used to
reduce Giardia levels, EPA believed that the national cost based on
providing additional disinfectant contact time is probably
representative, on average, of other modifications that systems might
implement. The Agency chose this methodology for estimating costs
because it was the most simple. Moreover, insufficient data prevents
the Agency from predicting with any reliability the mix of different
technologies systems would use to comply. EPA recognizes that in lieu
of expanding contact basin size, some systems may achieve the required
Giardia reductions through increased disinfectant dosages, improved
sedimentation and filtration efficiencies, or use of a stronger
disinfectant such as ozone. Smaller systems, especially those serving
fewer than 1,000 people, might use cartridge filters, or membrane
technology rather than additional contact time to achieve compliance
with the long-term ESWTR and other drinking water regulations at lower
cost. In addition, the costs for utilities to meet the D/DBP
regulations (proposed elsewhere in today's Federal Register) are not
necessarily additive with the costs for utilities to meet either the
interim or long-term ESWTR. For example, systems installing membrane
technology to comply with the D/DBP rule would also be expected through
use of this technology to comply with the ESWTR. Use of technologies
other than increasing contact basin time might be more feasible and
less expensive for some systems, depending on site-specific factors
(e.g., limited availability of land) and overall treatment objectives
(e.g., meeting other regulatory requirements such as the D/DBR rule).
EPA solicits comment on how many systems might use these
alternative approaches for meeting ESWTR requirements and whether the
use of such technologies would lead to substantially different cost
estimates. EPA does not believe there are sufficient data to predict
the costs for reducing Cryptosporidium to a desired risk level as has
been done for Giardia. EPA solicits comment on what approaches might be
taken for estimating national treatment costs for systems to provide
different levels of Cryptosporidium removal depending on
Cryptosporidium densities in the source water. Also, EPA requests
comment on whether it is reasonable to assume that any treatment
changes that are made to remove Cryptosporidium would also remove
Giardia, thereby not duplicating costs for compliance.
Table VI-2 indicates a range of estimated increases in household
costs by system size category for systems needing to achieve an
additional 0.5 log to 3 log reduction of Giardia to comply with the
ESWTR option described above. By this analysis 35 percent of the
systems would not be required to make any changes in treatment and
would incur no costs. For the interim ESWTR, estimated increases in
household costs for systems required to make changes in treatment would
range from $11 to $49 per household per year in the smallest size
category (serving a median population of 15,000 people) to $3.1 to $24
per household per year in the largest size category (serving a median
population of 1,550,000 people).
If the analyzed criteria for the interim ESWTR were extended to
smaller systems under the long-term ESWTR, and systems used additional
disinfectant contact time to meet such criteria, increases in
annualized household costs would range from $360 to $1100 per household
per year in the smallest size category (serving a median population of
57 people) to $27 to $85 per household per year in systems with a
median population of 5,500. As stated above, EPA believes that smaller
systems should be able to use a more economic treatment alternative
than additional disinfectant contact time.
EPA solicits comment on whether the system level costs to achieve
the different log reductions indicated in Table VI-2 by disinfection,
or other means, are reasonable and accurate.
Table VI-3 indicates the estimated labor effort by the number of
full time employees (FTEs), hours, and dollar costs for States to
implement the interim ESWTR. If systems, rather than the State, were to
fund some or all sanitary surveys, then State costs would be reduced
accordingly. Further details of this analysis are available in the
Regulatory Impact Analysis (EPA, 1994).
Table VI-1--Estimated National Contact Basin Costs for Enhanced SWTR
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cost estimates based on additional disinfectant contact basin size\1\
-------------------------------------------------------------------------------------------
Number of affected systems Total capital cost (M$) Total annualized cost (M$)
Population per -------------------------------------------------------------------------------------------
System size category system Filtering systems Filtering systems Filtering systems
-------------------------------------------------------------------------------------------
W/out W/out W/out
soft W/soft Total soft W/soft Total soft W/soft Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................... 25-100 493 8 501 22 0.5 23 4 0.09 4
2......................................... 101-500 454 13 467 42 1.4 43 8 0.3 8
3......................................... 501-1K 415 47 462 86 12 98 16 2 18
4......................................... 1K-3.3K 586 61 647 200 24 224 25 3 28
5......................................... 3.3K-10K 627 104 731 360 72 432 45 9 54
6......................................... 10K-25K 291 67 358 330 94 424 34 10 44
7......................................... 25K-50K 167 42 209 340 110 450 36 12 47
8......................................... 50K-75K 77 24 101 230 92 322 24 10 34
9......................................... 75K-100K 63 7 70 250 37 287 26 4 30
10........................................ 100K-500K 88 24 112 620 230 850 67 25 92
11........................................ 500K-1M 22 5 27 600 170 770 64 18 83
12........................................ 1M+ 9 1 10 460 97 557 50 11 60
-------------------------------------------------------------------------------------------------------------
Totals:
Interim Rule (Systems > 10K)........ ................ 716 170 887 2830 831 3661 302 88 391
Long-Term Rule (All Systems)........ ................ 3,290 404 3,694 3,540 941 4,481 401 103 504
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\Cost estimates were developed on the basis of the following assumptions: 1) 35 percent of surface water systems currently meet ESWTR inactivation
requirements (based on LeChevallier et al., 1991); 2) the amount of additional inactivation required by systems that do not currently meet ESWTR
requirements is based on the distribution of source water Giardia concentrations in the LeChevallier data; and 3) the additional basin volume is based
upon CT requirements of the SWTR guidance document with: pH = 8 (non-softening) or 9 (softening), t10 : ttheoretical = 0.7, temperature = 5 deg.C,
and C12 residual = 1 mg/l.
Table VI-2--Estimated Increases in Annual Houshold Costs for Systems Expanding Contact Basin Size to Meet an
Enhanced SWTR\2\
----------------------------------------------------------------------------------------------------------------
Total household costs, $/hh/yr\3\
-----------------------------------------------------------
Cat. # Median pop. Filter\4\ Filter and Soften\4\
-----------------------------------------------------------
Min Avg\1\ Max Min Avg\1\ Max
----------------------------------------------------------------------------------------------------------------
1................................... 57 360 420 960 430 500 1,100
2................................... 225 170 200 450 200 240 540
3................................... 750 88 120 310 110 150 350
4................................... 1,910 36 52 110 43 59 130
5................................... 5,500 27 28 67 30 34 85
6................................... 15,000 11 15 40 13 19 49
7................................... 35,000 7.9 12 30 10 15 39
8................................... 60,000 6.6 10 26 8.8 13 34
9................................... 88,100 6.1 8.8 24 7.5 12 32
10.................................. 175,000 5.1 8.5 24 6.6 11 33
11.................................. 730,000 3.5 6.7 20 4.7 9.1 27
12.................................. 1,550,000 3.1 6.0 18 4.2 8.2 24
----------------------------------------------------------------------------------------------------------------
Notes:
\1\Costs assume that 35 percent of systems currently meet ESWTR requirements (LeChevallier et al., 1991) and
therefore do not require contact basin modifications.
\2\Assumes Giardia and level of treatment distributions per LeChevallier et al, 1991 are nationally
representative of arithmetic averages, and that systems under ESWTR are required to provide additional
disinfection inactivation to meet a less than 1/10,000 annual infection rate at the first customer calculated
according to the Giardia infectivity dose response curve of Rose et al. (1991).
\3\Household costs represent costs for affected systems. Minimum costs are based on costs for systems requiring
additional 0.5 log inactivation while maximum costs are based on requiring an additional 3-log inactivation.
Average costs are based on distribution of costs for achieving different inactivations based on data by
LeChevallier et al. (1991).
\4\Contact basin size dependent upon chlorine residual, pH and temperature. Contact basin costs will increase if
chlorine residual or temperature decrease or if pH increases. For non-softening systems (``Filter'' and
``Unfilt'') pH=8, temperature=5 deg.C, and chlorine residual=1 mg/L. For softening systems (``Soften''),
pH=9, temperature=5 deg.C, and chlorine residual=1 mg/L.
Table VI-3.--Interim Enhanced Surface Water Treatment Rule State Program Costs Model
----------------------------------------------------------------------------------------------------------------
National burden
Variable Default assumptions ------------------------- Cost
In FTEs In hours
----------------------------------------------------------------------------------------------------------------
Regulation Adoption and 0.5 FTE per State............. 1 28.0 47,040 $1,540,000
Program Development.
Review Plans and Specs........ 10 days/large system.......... 112 \1\N/A \1\N/A \1\N/A
Log Removal Determination..... 3 days per surface water 19 19.0 31,958 1,046,250
system.
---------------------------------------------------------------------------------
Subtotal (x)............ .............................. ....... 47 78,998 2,586,250
Staff Training (Rule Specific) 10 days per technical FTE=f(x) 0 2.1 3,591 117,557
Sanitary Surveys\3\........... 5 days/lg. sys./survey; 2 days/ 79 78.7 132,147 4,326,250
sm. sys./survey.
=================================================================================
Total................... .............................. ....... 128 214,736 7,030,057
Average Annual Cost over 3.5 .............................. ....... 37 61,353 2,008,588
years\2\.
----------------------------------------------------------------------------------------------------------------
\1\Costs for reviewing plans and specifications for the ESWTR are counted as a joint activity undertaken with
the same step of implementing the Stage 1 DBP Rule and are included in the DBP Rule RIA.
\2\Total cost and burden are divided by 3.5 years, the time between promulgation of this rule and the final
ESWTR.
\3\Recordkeeping burden is assumed to equal approximately 2% of the burden shown (i.e. approximately 1.6 FTEs,
2,640 hours, $86,000).
B. Benefits of Proposed Rule
The level of reduction of waterborne illness resulting from
implementation of this rule will largely depend on the particular
option(s) promulgated. Even if EPA could predict the most suitable
option(s), the Agency cannot yet predict the number of illnesses
avoided until more data become available. EPA anticipates that much of
such data, particularly on national pathogen occurrence and existing
treatment levels, will become available under the forthcoming ICR.
With the limited available data, EPA has used a disinfection
byproducts risk assessment model (DBPRAM) to estimate potential risks
from Giardia that might result from systems complying with different
DBP standards both with the existing SWTR and an ESWTR (Grubbs et al
1992; Regli et al 1993; Cromwell et al 1992). In this analysis, EPA
assumed that the ESWTR would require systems to remove/inactivate
Giardia by 3, 4, 5, or 6 logs if the Giardia concentrations in the
source water were <1 cysts/100="" l,="" 1-9="" cysts/100="" l,="" 10-99="" cysts/100="" l,="" and="" 100="" cysts/100="" l="" or="" more,="" respectively.="" this="" assumption="" is="" consistent="" with="" current="" epa="" guidance="" (epa,="" 1991a).="" because="" of="" the="" limited="" data,="" epa="" used="" the="" dbpram="" only="" for="" the="" category="" of="" surface="" water="" systems="" that="" serve="" at="" least="" 10,000="" people="" and="" practice="" coagulation,="" sedimentation,="" and="" filtration,="" but="" do="" not="" soften="" the="" water.="" collectively="" this="" group="" of="" systems="" provides="" water="" to="" about="" 103="" million="" people.="" epa="" assumed="" as="" part="" of="" the="" modeling="" effort="" that="" (1)="" giardia="" densities="" in="" source="" waters="" in="" the="" u.s.="" are="" represented="" by="" the="" survey="" data="" of="" lechevallier="" et="" al.="" (1991a),="" (2)="" systems="" are="" using,="" or="" will="" use,="" the="" least="" expensive="" technologies="" to="" comply="" with="" the="" swtr="" and="" existing="" tthm="" standard,="" and="" (3)="" systems="" comply="" only="" minimally="" with="" both="" the="" swtr="" (i.e.,="" provide="" a="" 3-log="" removal/inactivation="" of="" giardia="" cysts="" and="" maintain="" a="" disinfectant="" residual="" throughout="" the="" distribution="" system)="" and="" the="" existing="" tthm="" standard.="" using="" these="" assumptions,="" the="" model="" predicts="" that,="" without="" revising="" the="" swtr,="" several="" hundred="" thousand="" people="" would="" become="" infected="" by="" giardia="" each="" year.="" these="" predicted="" risks="" may="" be="" significantly="" overstated="" because="" many="" systems="" currently="" appear="" to="" provide="" more="" treatment="" than="" is="" minimally="" required="" under="" the="" swtr="" (lechevallier="" et="" al.,="" 1991b).="" also,="" concentrations="" of="" giardia="" cysts="" in="" source="" waters="" in="" the="" u.s.="" may="" be="" significantly="" less="" than="" those="" indicated="" by="" the="" survey="" results="" of="" lechevallier="" et="" al.="" (1991a),="" which="" did="" not="" cover="" all="" geographical="" locations.="" the="" dbpram="" also="" predicted="" that,="" in="" the="" absence="" of="" any="" revision="" to="" the="" swtr,="" as="" the="" hypothetical="" mcl="" for="" dbps="" decreases="" (i.e.,="" either="" for="" tthms="" or="" the="" sum="" of="" five="" haloacetic="" acids),="" the="" incidence="" of="" giardia="" infection="" significantly="" increases.="" one="" reason="" for="" this="" result="" is="" that="" lower="" mcls="" would="" lead="" systems="" to="" use="" more="" efficient="" precursor="" removal="" technologies,="" resulting="" in="" a="" lower="" disinfectant="" demand="" in="" the="" water.="" therefore,="" since="" less="" disinfectant="" is="" necessary,="" a="" lower="" ct="" value="" may="" result="" at="" the="" first="" customer.="" without="" the="" removal="" of="" dbp="" precursors="" (or="" associated="" disinfectant="" demand),="" systems="" would="" need="" to="" maintain="" a="" higher="" ct="" value="" at="" the="" first="" customer="" to="" maintain="" a="" disinfectant="" residual="" throughout="" the="" distribution="" system.="" a="" second="" reason="" why="" the="" predicted="" incidence="" of="" giardia="" infection="" increases="" as="" the="" mcl="" for="" dbps="" is="" lowered="" is="" that="" the="" model="" assumes="" that="" many="" systems="" would="" switch="" to="" chloramine="" as="" a="" residual="" disinfectant,="" or="" to="" ozone="" followed="" by="" chloramine,="" to="" limit="" the="" formation="" of="" chlorinated="" dbps.="" chloramine="" is="" a="" weaker="" disinfectant="" than="" chlorine="" and="" consequently="" would="" result="" in="" less="" giardia="" inactivation.="" similarly,="" the="" model="" also="" assumes="" that="" if="" a="" system="" were="" to="" switch="" to="" ozone="" for="" primary="" disinfection,="" followed="" by="" chloramine,="" the="" system="" would="" provide="" only="" enough="" disinfection="" to="" inactivate="" 0.5="" logs="" of="" giardia="" to="" minimally="" meet="" the="" swtr="" (assuming="" that="" 2.5="" log="" of="" giardia="" removal="" is="" achieved="" by="" physical="" means).="" this="" latter="" assumption="" may="" underestimate="" the="" actual="" level="" of="" giardia="" inactivation="" that="" a="" system="" would="" likely="" provide,="" since="" for="" a="" relatively="" small="" increase="" in="" cost="" compared="" to="" that="" for="" ozone="" installation,="" the="" system="" could="" achieve="" (by="" increasing="" the="" ozone="" dose="" or="" contact="" time)="" a="" significantly="" greater="" level="" of="" inactivation="" than="" the="" 3-="" log="" reduction="" specified="" by="" the="" swtr="" for="" giardia.="" the="" dbpram="" also="" predicts="" that="" under="" more="" stringent="" dbp="" standards,="" if="" such="" systems="" were="" to="" only="" minimally="" meet="" the="" swtr,="" the="" incidence="" of="" waterborne="" disease="" outbreaks="" would="" significantly="" increase="" in="" systems="" with="" the="" worst="" quality="" source="" waters="" (but="" apparently="" not="" in="" those="" with="" good="" quality="" source="" waters)="" (grubbs="" et="" al.,="" 1992;="" regli="" et="" al.,="" 1993).="" in="" its="" modeling="" effort,="" epa="" defined="" waterborne="" disease="" outbreaks="" (epidemic="" disease)="" as="" one="" in="" which="" at="" least="" 1%="" of="" the="" population="" became="" infected="" (conservatively="" used="" as="" an="" indicator="" for="" illness)="" within="" a="" 30-="" day="" period;="" this="" definition="" was="" used="" because="" epa="" believes="" that="" at="" incidence="" lower="" than="" 1%="" health="" authorities="" are="" generally="" not="" aware="" that="" an="" outbreak="" is="" in="" progress,="" unless="" the="" disease="" is="" typically="" very="" debilitating="" or="" life-threatening.="" according="" to="" harrington="" et="" al.="" (1985),="" the="" total="" cost="" of="" disease="" avoidance="" behavior,="" such="" as="" boiling="" or="" purchase="" of="" bottled="" water="" by="" the="" entire="" community,="" during="" an="" outbreak="" far="" exceeds="" the="" total="" cost="" of="" treating="" the="" illness.="" the="" dbpram="" predicts="" that="" eswtr="" compliance,="" as="" described="" above,="" would="" result="" in="" no="" more="" than="" a="" few="" hundred="" infections="" caused="" by="" waterborne="" giardia="" per="" year="" per="" 100="" million="" people.="" this="" is="" several="" hundred="" thousand="" cases="" fewer="" than="" predicted="" in="" the="" absence="" of="" an="" eswtr.="" in="" the="" absence="" of="" more="" data="" and="" for="" the="" purpose="" of="" simplicity,="" the="" model="" assumes="" that="" systems="" would="" use="" the="" arithmetic="" mean="" (based="" on="" lechevallier="" et="" al.,="" 1991a)="" to="" calculate="" pathogen="" densities,="" and="" use="" the="" coldest="" water="" temperature="" and="" maximum="" flow="" rate="" (design="" rate)="" to="" determine="" disinfection="" conditions="" at="" which="" plants="" would="" operate.="" use="" of="" the="" arithmetic="" mean="" may="" underestimate="" the="" predicted="" risk="" since="" values="" above="" the="" mean="" may="" result="" in="" a="" greater="" number="" of="" infections="" than="" values="" below="" the="" mean.="" in="" contrast,="" using="" the="" design="" flow="" rate="" throughout="" the="" year="" for="" model="" predictions="" overestimates="" the="" predicted="" risk,="" because="" the="" flow="" rate="" should="" be="" significantly="" less="" during="" colder="" weather,="" which="" would="" result="" in="" longer="" contact="" times="" and="" greater="" ct="" values,="" and="" therefore="" greater="" inactivation="" of="" giardia="" than="" if="" the="" system="" operated="" under="" design="" flow="" conditions="" during="" this="" period.="" in="" addition,="" use="" of="" the="" coldest="" water="" temperature="" throughout="" the="" year="" for="" model="" predictions="" also="" overestimates="" the="" predicted="" risk,="" because="" disinfectants="" are="" more="" effective="" at="" warmer="" water="" temperatures="" for="" a="" given="" ct.="" in="" the="" absence="" of="" more="" data,="" epa="" cannot="" determine="" whether="" the="" model="" assumptions,="" collectively,="" may="" significantly="" bias="" the="" model="" predictions.="" epa="" solicits="" comment="" on="" this="" issue="" and="" requests="" suggestions="" on="" how="" epa="" can="" improve="" the="" assumptions="" in="" the="" model,="" based="" upon="" data="" collected="" under="" the="" icr="" (59="" fr="" 6332;="" proposed="" february="" 10,="" 1994).="" the="" model="" also="" predicts="" that="" if="" systems="" complied="" with="" an="" eswtr,="" no="" waterborne="" disease="" outbreaks="" (as="" defined="" above)="" attributed="" to="" giardia="" would="" occur.="" since="" giardia="" is="" more="" resistant="" to="" disinfection="" than="" most="" other="" pathogens="" (cryptosporidium="" being="" a="" notable="" exception),="" epa="" assumes="" that="" the="" incidence="" of="" waterborne="" disease="" caused="" by="" other="" pathogens="" would="" also="" be="" substantially="" reduced.="" the="" disease,="" giardiasis,="" causes="" a="" gastrointestinal="" disorder="" that="" may="" be="" mild="" or="" severe="" and="" incapacitating,="" and="" that="" generally="" lasts="" from="" one="" to="" four="" weeks.="" although="" mortality="" is="" very="" low="" (0.0001%),="" some="" patients,="" including="" otherwise="" healthy="" individuals,="" require="" hospitalization="" (about="" 4600="" annually)="" (bennett="" et="" al.,="" 1987;="" addiss="" and="" lengerich,="" 1994).="" an="" individual="" with="" giardiasis="" typically="" has="" one="" or="" more="" of="" the="" following="" symptoms:="" diarrhea,="" cramps,="" abdominal="" distress,="" flatulence,="" fatigue,="" vomiting,="" chills,="" fever,="" and="" marked="" weight="" loss.="" in="" one="" study="" of="" 105="" stool-positive="" cases="" of="" travelers="" returning="" to="" the="" u.s.,="" 39="" percent="" had="" mild="" symptoms,="" 41="" percent="" had="" moderate="" symptoms,="" 6.7="" percent="" had="" incapacitating="" or="" severe="" symptoms,="" and="" 13.3="" percent="" had="" no="" symptoms="" (wolfe,="" 1990).="" all="" age="" groups="" are="" affected.="" the="" average="" time="" between="" infection="" and="" the="" onset="" of="" disease="" is="" about="" two="" weeks,="" although="" this="" may="" vary="" considerably.="" chronic="" cases="" that="" persist="" for="" months="" or="" longer="" are="" not="" uncommon.="" in="" the="" original="" swtr="" regulatory="" impact="" analysis="" (epa,="" 1989a),="" the="" estimated="" economic="" cost="" associated="" with="" waterborne="" giardiasis="" was="" based="" on="" a="" study="" of="" costs="" incurred="" during="" an="" outbreak="" of="" waterborne="" giardiasis="" in="" 1983="" that="" occurred="" in="" scranton,="" pennsylvania="" (harrington,="" et="" al.,="" 1985).="" in="" this="" study,="" the="" investigators="" estimated="" that="" the="" medical="" cost="" and="" the="" cost="" of="" time="" lost="" from="" work="" associated="" with="" the="" outbreak="" was="" in="" the="" range="" of="" $1245="" to="" $1878="" per="" case="" (1984="" dollars).="" the="" lower="" cost="" values="" the="" time="" loss="" for="" homemakers,="" retired="" persons,="" and="" unemployed="" persons="" as="" zero,="" while="" the="" higher="" cost="" values="" the="" time="" loss="" for="" these="" people="" at="" the="" average="" wage="" rate.="" the="" above="" estimate="" was="" based="" on="" the="" results="" of="" a="" survey="" of="" 370="" people="" who="" had="" ``confirmed''="" cases="" of="" giardiasis,="" i.e.,="" a="" positive="" stool="" sample.="" epa="" assumed="" in="" the="" analysis="" that="" the="" costs="" associated="" with="" confirmed="" cases="" are="" representative="" of="" the="" costs="" associated="" with="" those="" who="" had="" symptoms="" of="" giardiasis,="" but="" where="" no="" stool="" sample="" was="" examined,="" since="" medical="" costs="" (minus="" the="" cost="" for="" a="" stool="" specimen="" examination)="" and="" cost="" for="" time="" lost="" from="" work="" should="" be="" similar="" when="" symptoms="" are="" similar.="" the="" $1245-$1878="" estimate="" above="" does="" not="" take="" into="" account="" fatalities="" associated="" with="" waterborne="" disease.="" according="" to="" bennett="" et="" al.="" (1987),="" about="" 0.1="" percent="" of="" cases="" of="" waterborne="" disease="" are="" fatal.="" although="" these="" investigators="" estimate="" that="" the="" mortality="" rate="" for="" giardiasis="" is="" much="" lower="" than="" 0.1="" percent,="" epa="" believes="" that="" control="" of="" giardia="" will="" also="" control="" other="" waterborne="" disease="" agents="" that="" have="" a="" higher="" mortality="" rate="" than="" giardia.="" therefore,="" by="" omitting="" the="" risk="" of="" mortality="" associated="" with="" waterborne="" disease,="" epa's="" analysis="" may="" represent="" a="" significant="" underestimate="" of="" the="" benefits.="" in="" addition,="" epa's="" analysis="" did="" not="" consider="" benefits="" associated="" with="" avoiding="" the="" economic="" and="" psychological="" costs="" to="" the="" affected="" community="" (including="" businesses="" and="" government)="" associated="" with="" a="" waterborne="" disease="" outbreak,="" nor="" did="" it="" consider="" the="" benefits="" of="" additional="" public="" confidence="" in="" an="" enhanced="" water="" supply.="" these="" benefits="" were="" not="" considered="" in="" the="" analysis="" because="" of="" the="" difficulty="" of="" quantifying="" them.="" adjusting="" the="" $1878/case="" value="" for="" inflation="" (through="" 1993),="" and="" including="" a="" factor="" for="" willingness-to-pay,="" epa="" estimates="" the="" benefit="" would="" be="" $3,000="" per="" giardia="" infection="" avoided.="" using="" this="" estimate,="" the="" 400,000="" to="" 500,000="" giardia="" infections="" per="" year="" that="" could="" be="" avoided="" in="" large="" surface="" water="" systems="" would="" have="" an="" economic="" value="" of="" $1.2="" to="" $1.5="" billion="" per="" year.="" this="" suggests="" that="" the="" benefit="" nationwide="" of="" avoiding="" giardia="" infections="" in="" large="" systems="" is="" as="" much="" as="" three="" or="" four="" times="" greater="" than="" the="" estimated="" $391="" million="" national="" cost="" per="" year="" to="" provide="" additional="" disinfectant="" contact="" time.="" at="" a="" household="" level,="" the="" interim="" eswtr="" would="" impose="" costs="" ranging="" from="" $11-="" $49/household/year="" in="" systems="" serving="" 15,000="" people="" to="" $3-="" $24/household/year="" in="" systems="" serving="" 1,550,000.="" household="" costs="" are="" a="" useful="" guide="" for="" examining="" cost-benefit="" tradeoffs,="" because="" they="" are="" easier="" to="" understand="" in="" assessing="" the="" public's="" willingness="" to="" pay="" for="" a="" more="" stringent="" rule.="" epa="" does="" not="" believe="" that="" the="" household="" costs="" predicted="" by="" this="" analysis="" represents="" an="" unreasonable="" premium="" for="" the="" systems="" affected="" by="" the="" interim="" eswtr,="" considering="" the="" nature="" of="" microbial="" risk.="" there="" are="" at="" least="" three="" approaches="" for="" examining="" the="" tradeoff="" between="" costs="" and="" benefits.="" one="" approach="" is="" to="" determine="" the="" cost="" of="" the="" eswtr="" alone.="" in="" a="" second="" approach,="" epa="" could="" use="" the="" combined="" cost="" of="" the="" swtr="" and="" eswtr,="" since="" customers="" of="" many="" water="" systems="" are="" already="" paying,="" or="" will="" soon="" be="" paying,="" an="" extra="" premium="" for="" microbial="" protection="" as="" a="" result="" of="" the="" original="" swtr.="" if="" this="" second="" approach="" is="" used="" (the="" most="" expensive="" estimate="" of="" eswtr="" cost),="" and="" if="" the="" cost="" of="" the="" original="" swtr="" is="" adjusted="" for="" inflation="" and="" factored="" into="" the="" above="" analysis,="" the="" overall="" ratio="" of="" benefits="" to="" costs="" would="" still="" be="" about="" a="" break-even="" proposition.="" household="" costs="" would="" be="" significantly="" higher="" for="" previously="" unfiltered="" systems="" and="" modestly="" higher="" for="" previously="" filtered="" systems.="" in="" the="" third="" approach,="" epa="" could="" assume="" that="" a="" large="" share="" of="" the="" cost="" of="" an="" eswtr="" should="" be="" borne="" by="" the="" dbp="" rule,="" since="" the="" treatment="" changes="" needed="" to="" meet="" more="" stringent="" dbp="" regulations="" may="" increase="" the="" pathogen="" risk="" that="" the="" eswtr="" must="" address.="" the="" accounting="" difficulty="" of="" sorting="" between="" microbial="" and="" dbp="" costs="" will="" become="" even="" more="" complicated="" later="" in="" developing="" the="" long-="" term="" eswtr,="" which="" will="" cover="" small="" systems.="" household="" costs="" for="" providing="" additional="" disinfectant="" contact="" time="" in="" small="" systems="" are="" significantly="" greater="" than="" those="" for="" the="" larger="" systems.="" however,="" it="" is="" not="" clear="" that="" small="" systems="" will="" choose="" to="" meet="" the="" long-term="" eswtr="" by="" increasing="" the="" contact="" time.="" such="" options="" as="" small="" scale="" membrane="" treatment="" systems="" may="" provide="" a="" more="" economical="" means="" of="" meeting="" both="" microbial="" and="" dbp="" treatment="" requirements="" simultaneously.="" in="" that="" case,="" the="" microbial="" and="" dbp-related="" control="" costs="" would="" be="" truly="" indistinguishable="" from="" each="" other.="" a="" similar="" analysis="" to="" the="" one="" described="" above="" for="" giardia="" is="" not="" yet="" feasible="" for="" cryptosporidium="" because="" of="" much="" greater="" data="" deficiencies.="" the="" analysis="" of="" national="" benefits="" for="" the="" different="" eswtr="" options="" must="" remain="" highly="" speculative,="" even="" for="" giardia,="" until="" more="" data="" become="" available.="" epa="" intends="" to="" develop="" a="" more="" complete="" cost="" and="" benefit="" analysis="" for="" the="" different="" eswtr="" options="" based="" on="" data="" generated="" under="" the="" icr="" and="" complementary="" research.="" this="" analysis="" would="" examine="" the="" costs="" of="" the="" various="" treatment="" options="" indicated="" in="" section="" iiie="" above,="" using="" various="" statistical="" approaches="" to="" calculate="" pathogen="" densities="" (e.g.,="" mean="" value="" versus="" 90th="" percentile="" value),="" acceptable="" risk="" levels,="" pathogen="" infectivities,="" and="" various="" assumptions="" about="" the="" analytical="" methods="" (e.g.,="" cyst/oocyst="" viability,="" percent="" recovery)="" and="" include="" a="" broader="" discussion="" of="" the="" benefits.="" epa="" intends="" to="" present="" such="" analysis="" in="" a="" notice="" of="" availability="" in="" the="" federal="" register="" by="" november="" 1995.="" this="" notice="" will="" indicate="" the="" basis="" for="" epa's="" preferred="" eswtr="" option(s)="" and="" solicit="" comment="" on="" the="" appropriateness="" for="" promulgating="" this="" option(s)="" as="" part="" of="" the="" interim="" eswtr.="" epa="" solicits="" comment="" on="" approaches="" that="" can="" be="" used="" for="" this="" analysis.="" vii.="" other="" statutory="" requirements="" a.="" executive="" order="" 12866="" under="" executive="" order="" 12866="" (58="" fr="" 51735="" (october="" 4,="" 1993)),="" the="" agency="" must="" determine="" whether="" the="" regulatory="" action="" is="" ``significant''="" and="" therefore="" subject="" to="" omb="" review="" and="" the="" requirements="" of="" the="" executive="" order.="" the="" order="" defines="" ``significant="" regulatory="" action''="" as="" one="" that="" is="" likely="" to="" result="" in="" a="" rule="" that="" may:="" (1)="" have="" an="" annual="" effect="" on="" the="" economy="" of="" $100="" million="" or="" more="" or="" adversely="" affect="" in="" a="" material="" way="" the="" economy,="" a="" sector="" of="" the="" economy,="" productivity,="" competition,="" jobs,="" the="" environment,="" public="" health="" or="" safety,="" or="" state,="" local,="" or="" tribal="" governments="" or="" communities;="" (2)="" create="" a="" serious="" inconsistency="" or="" otherwise="" interfere="" with="" an="" action="" taken="" or="" planned="" by="" another="" agency;="" (3)="" materially="" alter="" the="" budgetary="" impact="" of="" entitlement,="" grants,="" user="" fees,="" or="" loan="" programs="" or="" the="" rights="" and="" obligations="" of="" recipients="" thereof;="" or="" (4)="" raise="" novel="" legal="" or="" policy="" issues="" arising="" out="" of="" legal="" mandates,="" the="" president's="" priorities,="" or="" the="" principles="" set="" forth="" in="" the="" executive="" order.="" pursuant="" to="" the="" terms="" of="" executive="" order="" 12866,="" it="" has="" been="" determined="" that="" this="" rule="" is="" a="" ``significant="" regulatory="" action''="" because="" it="" will="" have="" an="" annual="" effect="" on="" the="" economy="" of="" $100="" million="" or="" more.="" as="" such,="" this="" action="" was="" submitted="" to="" omb="" for="" review.="" changes="" made="" in="" response="" to="" omb="" suggestions="" or="" recommendations="" will="" be="" documented="" in="" the="" public="" record.="" b.="" regulatory="" flexibility="" act="" the="" regulatory="" flexibility="" act,="" 5="" u.s.c.="" 602="" et="" seq.,="" requires="" epa="" to="" explicitly="" consider="" the="" effect="" of="" proposed="" regulation="" on="" small="" entities.="" by="" policy,="" epa="" has="" decided="" to="" consider="" regulatory="" alternatives="" if="" there="" is="" any="" economic="" impact="" on="" any="" number="" of="" small="" entities.="" the="" small="" business="" administration="" defines="" a="" ``small="" water="" utility''="" as="" one="" which="" serves="" fewer="" than="" 3,300="" people.="" the="" proposed="" rule="" is="" consistent="" with="" the="" objectives="" of="" the="" regulatory="" flexibility="" act="" because="" it="" will="" not="" have="" any="" economic="" impact="" on="" any="" small="" entities.="" except="" for="" the="" sanitary="" survey="" requirement,="" which="" epa="" believes="" will="" be="" conducted="" by="" states,="" the="" rule="" would="" only="" apply="" to="" systems="" serving="" at="" least="" 10,000="" people.="" therefore,="" the="" agency="" believes="" that="" this="" notice="" would="" have="" no="" adverse="" effect="" on="" any="" number="" of="" small="" entities.="" c.="" paperwork="" reduction="" act="" the="" information="" collection="" requirements="" in="" this="" proposed="" rule="" have="" been="" submitted="" for="" approval="" to="" the="" office="" of="" management="" and="" budget="" (omb)="" under="" the="" paperwork="" reduction="" act,="" 44="" u.s.c.="" 3501="" et="" seq.="" an="" information="" collection="" request="" document="" has="" been="" prepared="" by="" epa="" (icr="" no.="" 270.32)="" and="" a="" copy="" may="" be="" obtained="" from="" sandy="" farmer,="" information="" policy="" branch="" (mc:2136),="" epa,="" 401="" m="" street,="" sw,="" washington,="" dc="" 20460,="" or="" by="" calling="" (202)="" 260-2740.="" the="" reporting="" and="" recordkeeping="" burden="" for="" this="" proposed="" collection="" of="" information="" will="" be="" phased="" in="" starting="" in="" 1997.="" the="" specific="" burden="" anticipated="" for="" each="" category="" of="" respondent,="" by="" year,="" is="" shown="" below:="" 1997="" public="" water="" systems--monitoring="" and="" reporting="" hours="" per="" respondent:="" 0="" total="" hours:="" 0="" public="" water="" systems--recordkeeping="" hours="" per="" respondent:="" 0="" total="" hours:="" 0="" state="" program="" costs--reporting="" hours="" per="" respondent:="" 1,599="" total="" hours:="" 89,518="" state="" program="" costs--recordkeeping="" hours="" per="" respondent:="" 16="" total="" hours:="" 904="" 1998="" public="" water="" systems--monitoring="" and="" reporting="" hours="" per="" respondent:="" 0="" total="" hours:="" 0="" public="" water="" systems--recordkeeping="" hours="" per="" respondent:="" 0="" total="" hours:="" 0="" state="" program="" costs--reporting="" hours="" per="" respondent:="" 1,149="" total="" hours:="" 64,337="" state="" program="" costs--recordkeeping="" hours="" per="" respondent:="" 12="" total="" hours:="" 650="" 1999="" public="" water="" systems--monitoring="" and="" reporting="" hours="" per="" respondent:="" 0="" total="" hours:="" 0="" public="" water="" systems--recordkeeping="" hours="" per="" respondent:="" 0="" total="" hours:="" 0="" state="" program="" costs--reporting="" hours="" per="" respondent:="" 699="" total="" hours:="" 39,157="" state="" program="" costs--recordkeeping="" hours="" per="" respondent:="" 7="" total="" hours:="" 396="" send="" comments="" regarding="" the="" burden="" estimate="" or="" any="" other="" aspect="" of="" this="" collection="" of="" information,="" including="" suggestions="" for="" reducing="" this="" burden,="" to="" chief,="" information="" policy="" branch="" (mc:2136),="" epa,="" 401="" m="" street,="" sw,="" washington,="" dc="" 20460;="" and="" to="" the="" office="" of="" information="" and="" regulatory="" affairs,="" opm,="" washington,="" dc="" 20503,="" marked="" ``attention:="" desk="" officer="" for="" epa.''="" the="" final="" rule="" will="" respond="" to="" any="" omb="" or="" public="" comments="" on="" the="" information="" collection="" requirements="" contained="" in="" this="" proposal.="" d.="" science="" advisory="" board,="" national="" drinking="" water="" advisory="" council,="" and="" secretary="" of="" health="" and="" human="" services="" in="" accordance="" with="" section="" 1412="" (d)="" and="" (e)="" of="" the="" sdwa,="" epa="" consulted="" with="" the="" science="" advisory="" board,="" national="" drinking="" water="" advisory="" council,="" and="" secretary="" of="" health="" and="" human="" services="" and="" requested="" their="" comments="" in="" developing="" this="" rule.="" e.="" consultation="" with="" state,="" local,="" and="" tribal="" governments="" two="" executive="" orders="" (e.o.="" 12875,="" enhancing="" intergovernmental="" partnerships,="" and="" e.o.="" 12866,="" regulatory="" planning="" and="" review)="" explicitly="" require="" federal="" agencies="" to="" consult="" with="" state,="" local,="" and="" tribal="" entities="" in="" the="" development="" of="" rules="" and="" policies="" that="" will="" affect="" them,="" and="" to="" document="" what="" they="" did,="" the="" issues="" that="" were="" raised,="" and="" how="" the="" issues="" were="" addressed.="" as="" described="" in="" section="" i="" of="" today's="" rule,="" sdwa="" section="" 1412="" requires="" epa="" to="" promulgate="" npdwrs,="" to="" review="" each="" npdwr="" every="" three="" years,="" and="" to="" revise="" it="" as="" appropriate.="" in="" 1989,="" epa="" issued="" the="" swtr,="" in="" accordance="" with="" sdwa="" section="" 1412(b)(7)(c).="" that="" rule="" went="" into="" effect="" in="" 1991.="" that="" rule="" has="" since="" been="" reviewed="" and="" is="" being="" reproposed="" today.="" this="" proposal,="" which="" pertains="" only="" to="" systems="" serving="" more="" than="" 10,000="" persons,="" contains="" several="" options="" for="" final="" promulgation.="" depending="" on="" the="" option="" selected,="" pwss="" with="" poorer="" quality="" source="" waters="" may="" need="" to="" remove="" microbiological="" contaminants="" above="" levels="" currently="" required="" under="" the="" swtr.="" pwss="" may="" also="" be="" required="" to="" treat="" for="" cryptosporidium.="" there="" are="" currently="" insufficient="" data="" to="" develop="" an="" annual="" cost="" estimate="" of="" compliance="" with="" this="" rule.="" in="" 1992,="" epa="" considered="" entering="" into="" a="" negotiated="" rulemaking="" on="" a="" related="" disinfectant/disinfection="" by-products="" rule="" primarily="" because="" no="" clear="" path="" for="" addressing="" all="" the="" major="" issues="" associated="" with="" the="" d/="" dbp="" rule="" was="" apparent.="" epa="" hired="" a="" facilitator="" to="" explore="" this="" option="" with="" external="" stakeholders="" and,="" in="" november="" 1992,="" decided="" to="" proceed="" with="" the="" negotiation.="" the="" 18="" negotiators,="" including="" epa,="" met="" from="" november="" 1992="" until="" june="" 1993="" at="" which="" time="" agreement="" was="" reached="" on="" the="" content="" of="" the="" d/dbp="" proposed="" rule.="" that="" rule="" is="" proposed="" elsewhere="" in="" today's="" federal="" register.="" during="" the="" negotiations,="" the="" negotiators="" identified="" the="" possible="" need="" for="" a="" companion="" rule="" on="" surface="" water="" treatment.="" the="" purpose="" of="" the="" companion="" rule="" was="" to="" guard="" against="" the="" possibility="" of="" increasing="" microbial="" risk="" while="" controlling="" for="" disinfectant/disinfection="" byproduct="" risk.="" the="" contents="" of="" today's="" proposed="" regulatory="" and="" preamble="" language="" for="" enhanced="" surface="" water="" treatment="" have="" been="" agreed="" to="" by="" the="" 17="" negotiators="" who="" remained="" at="" the="" table="" through="" june="" 1993.="" a="" summary="" of="" those="" negotiations="" is="" contained="" in="" section="" ii.="" the="" negotiators="" included="" persons="" representing="" state="" and="" local="" governments.="" at="" the="" table="" were:="" (1)="" association="" of="" state="" drinking="" water="" administrators,="" a="" group="" representing="" state="" government="" officials="" responsible="" for="" implementing="" the="" regulations,="" (2)="" association="" of="" state="" and="" territorial="" health="" officials,="" a="" group="" representing="" statewide="" public="" health="" interests="" and="" the="" need="" to="" balance="" spending="" on="" a="" variety="" of="" health="" priorities,="" (3)="" national="" association="" of="" regulated="" utilities="" commissioners,="" a="" group="" representing="" funding="" concerns="" at="" the="" state="" level,="" (4)="" national="" association="" of="" county="" health="" officials,="" a="" group="" representing="" local="" government="" general="" public="" health="" interests,="" (5)="" national="" league="" of="" cities,="" a="" group="" representing="" local="" elected="" and="" appointed="" officials="" responsible="" for="" balancing="" spending="" needs="" across="" all="" government="" services,="" (6)="" national="" association="" of="" state="" utility="" consumer="" advocates,="" a="" group="" representing="" consumer="" interests="" at="" the="" state="" level,="" and="" (7)="" national="" consumer="" law="" center,="" a="" group="" representing="" consumer="" interests="" at="" the="" local="" level.="" in="" addition,="" several="" associations="" representing="" public="" municipal="" and="" investor-owned="" water="" systems="" also="" served="" on="" the="" committee.="" as="" part="" of="" the="" negotiation="" process,="" each="" of="" these="" representatives="" was="" responsible="" for="" obtaining="" endorsement="" from="" their="" respective="" organization="" on="" the="" positions="" they="" took="" at="" the="" negotiations="" and="" on="" the="" final="" signed="" agreement.="" during="" the="" negotiations,="" the="" group="" heard="" from="" many="" other="" parties="" who="" attended="" the="" public="" negotiations="" and="" were="" invited="" to="" express="" their="" views.="" as="" is="" true="" with="" any="" negotiation,="" all="" sides="" presented="" initial="" positions="" which="" were="" ultimately="" modified="" to="" obtain="" consensus="" from="" all="" sides.="" however,="" all="" parties="" mentioned="" above="" signed="" the="" final="" agreement="" on="" behalf="" of="" their="" associations.="" this="" agreement="" reflected="" basic="" consensus="" that="" the="" possible="" cost="" of="" the="" rule="" would="" be="" offset="" by="" its="" public="" health="" benefits="" and="" its="" promotion="" of="" responsible="" drinking="" water="" treatment="" practices.="" the="" only="" original="" negotiator="" who="" did="" not="" sign="" the="" agreement="" left="" the="" negotiations="" in="" march="" 1993.="" that="" negotiator="" represented="" the="" national="" rural="" water="" association="" (nrwa),="" a="" group="" representing="" primarily="" small="" public="" and="" private="" water="" systems.="" at="" the="" time="" that="" group="" left="" the="" negotiations,="" they="" were="" objecting="" to="" the="" cost="" of="" the="" d/dbp="" rule,="" which="" applies="" to="" all="" system="" sizes.="" except="" for="" a="" sanitary="" survey="" requirement="" that="" epa="" believes="" will="" be="" conducted="" by="" states,="" the="" interim="" eswtr="" would="" only="" apply="" to="" systems="" serving="" greater="" than="" 10,000="" persons="" and="" thus="" does="" not="" affect="" nrwa="" members.="" earlier="" in="" the="" negotiations,="" nrwa="" accepted="" the="" position="" that="" any="" control="" of="" disinfectants="" and="" disinfection="" by-products="" should="" not="" come="" at="" the="" expense="" of="" decreased="" protection="" from="" microbial="" contamination.="" the="" nrwa="" position="" that="" small="" systems="" should="" meet="" a="" less="" stringent="" trihalomethane="" standard="" than="" larger="" systems="" was="" rejected="" by="" the="" remaining="" negotiators,="" several="" of="" whom="" also="" represent="" small="" water="" systems.="" the="" contents="" of="" today's="" proposed="" rule="" has="" been="" available="" to="" the="" public="" for="" several="" months="" as="" part="" of="" the="" regulatory="" negotiation="" signature="" process.="" epa="" has="" briefed="" numerous="" groups,="" including="" government="" organizations,="" on="" its="" contents.="" the="" agency="" has="" received="" several="" letters="" from="" public="" water="" systems="" objecting="" to="" the="" cost="" of="" the="" proposed="" rule="" and="" questioning="" its="" potential="" health="" benefit.="" these="" letters="" are="" contained="" in="" the="" public="" docket="" supporting="" today's="" rule.="" the="" agency="" recognizes="" that="" many="" persons="" are="" concerned="" whether="" the="" proposed="" rule="" is="" warranted.="" the="" technical="" issues="" are="" complex.="" the="" process="" needed="" to="" develop="" a="" common="" level="" of="" understanding="" among="" the="" negotiators="" as="" to="" what="" was="" known="" and="" unknown="" and="" what="" are="" reasonable="" estimates="" of="" potential="" costs="" and="" benefits="" was="" time-consuming.="" it="" is="" unreasonable="" to="" expect="" persons="" not="" at="" the="" negotiating="" table="" to="" have="" that="" same="" level="" of="" understanding="" and="" to="" all="" share="" the="" same="" view.="" however,="" the="" discussions="" throughout="" the="" negotiated="" rulemaking="" process="" were="" informed="" by="" a="" broad="" spectrum="" of="" opinions.="" the="" agency="" believes="" this="" consensus="" proposal="" is="" not="" only="" the="" preferred="" approach="" but="" one="" which="" will="" generate="" informed="" debate="" and="" comment.="" viii.="" request="" for="" public="" comment="" epa="" solicited="" public="" comments="" on="" specific="" issues="" earlier="" in="" the="" preamble="" and="" welcomes="" comments="" on="" any="" other="" issue="" the="" public="" may="" wish="" to="" address.="" for="" ease="" in="" referring="" to="" requests="" for="" comments="" we="" are="" listing="" them="" below.="" in="" addition,="" at="" the="" end="" of="" this="" section,="" the="" agency="" is="" requesting="" comment="" on="" other="" issues="" not="" addressed="" earlier="" in="" the="" preamble.=""> (III.C) Rationale for setting MCLG of zero and a treatment
technique for Cryptosporidium
(III.D.1) Ground water under the direct influence of
surface water
--Including Cryptosporidium in rule language in definition of ground
water under the direct influence of surface water
--Revising guidance defining ground water under the influence of
surface water
--Most appropriate procedure for determining credits for removal/
inactivation and treatment requirements for systems using ground waters
under the direct influence of surface water
(III.D.3) Sanitary surveys
--Prerequisites for individuals performing sanitary survey (academic
degree, etc.)
--Revisions needed in SWTR Guidance Manual for conducting sanitary
survey for filtered systems and for evaluating vulnerability to
Cryptosporidium
--Frequency of sanitary surveys (three vs. five years)
(III.D.4) Possible supplemental requirements
--Whether to publish national rule to require systems to cover finished
water reservoirs and storage tanks, or whether this should be left to
State discretion. What would the cost be for such a rule, and what
waiver provisions would be appropriate.
--Whether EPA should require States and/or systems to have a cross-
connection control program; what specific criteria, if any, should be
included therein; how often such a program should be evaluated; under
what conditions a waiver could be granted; and whether only those
connections identified as a cross-connection by the public water system
or the State should be subject to a cross-connection program.
--Identification of measures other than cross-connection control
program to prevent the contamination of drinking water already in the
distribution system (e.g., minimum pressure requirements in the
distribution system).
--Whether to require systems to notify the State for persistent
turbidity levels above the performance standard (but not in violation
of this standard)
(III.E) Alternative Treatment Requirements
1. Options for defining pathogen densities
--Appropriateness of requiring systems whose population served grows to
over 10,000 to perform ICR monitoring.
--Appropriateness of the four approaches for calculating pathogen
densities, and whether approach selected should be based on number of
pathogen samples collected
2. Treatment alternative for controlling pathogens
--Appropriateness and magnitude of specific acceptable risk levels for
microbes
--Which treatment approach(es) is most appropriate
--Identification of approaches for achieving levels of pathogen removal
greater than 2.5 logs by physical means
--Utility of extrapolating CT values in SWTR Guidance Manual to predict
the effect on pathogens of higher levels of disinfection
--Appropriateness of two treatment alternatives, with possible
variations, for removal of Giardia
--Appropriateness of indicated treatment alternatives for
Cryptosporidium
--Feasibility of removing more than two logs of Cryptosporidium (with
and without disinfection being considered). -
Appropriateness of not
--Changing treatment specifications in SWTR
(VI) Economic Analysis
--What approaches are reasonable for estimating the national treatment
costs of requiring systems to remove a level of Cryptosporidium that
would depend on Cryptosporidium densities in the source water
--Are the system level costs in Table VI-2 for increasing the
disinfectant contact time reasonable and accurate
--The number of systems that might use control measures other than
increasing contact basin time requirements and whether the use of such
technologies would lead to substantially different cost estimates
--Assumption in estimating economic impact that treatment changes to
control Cryptosporidium will also control Giardia
--Soundness of assumptions made in disinfection byproducts risk
assessment model (DBPRAM) used to estimate potential risks from Giardia
that might result from systems complying with different DBP standards
both with the existing SWTR and an ESWTR, and how these assumptions
could be improved
Other Issues
How should EPA decide, in developing a forthcoming Notice
of Availability, what treatment approach(es) is most suitable for
additional public comment?
What criteria, if any, should the ESWTR include to ensure
that systems optimize treatment plant performance?
Should any turbidity performance criteria in the SWTR be
modified? For example, should the ESWTR require systems to base
compliance with the turbidity standards on monitoring the turbidity at
the effluent of each filter separately, in lieu of (or in addition to)
the confluence of all filters? Should any performance standard value be
changed?
To what extent should the ESWTR address the issue of
recycling filter backwash, given its potential for increasing the
densities of Giardia and Cryptosporidium on the filter?
Should the ESWTR define minimum certification criteria for
surface water treatment plant operators? Currently, the SWTR
(Sec. 141.70) requires such systems to be operated by ``qualified
personnel who meet the requirements specified by the State.''
Should the ESWTR include a performance standard(s) for
particle removal?
Under what conditions could systems be allowed different
log removal credits than is currently recommended in the SWTR Guidance
Manual?
IX. Instructions to Commenters
To ensure that EPA can read, understand and therefore properly
respond to comments, the Agency would prefer that commenters type or
print comments in ink, and cite, where possible, the paragraph(s) in
this proposed regulation (e.g. 141.76(b)) to which each comment refers.
Commenters should use a separate paragraph for each method or issue
discussed.
X. References
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List of Subjects
40 CFR Part 141
Intergovernmental relations, Reporting and recordkeeping
requirements, Water supply.
40 CFR Part 142
Administrative practice and procedure, Reporting and recordkeeping
requirements, Water supply
Dated: June 7, 1994.
Carol M. Browner,
Administrator.
For the reasons set forth in the preamble, Title 40 of the Code of
Federal Regulations is proposed to be amended as follows:
PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS
1. The authority citation for part 141 continues to read as
follows:
Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9.
2. Section 141.2 is amended by revising the definition of ``Ground
water under the direct influence of surface water'' to read as follows:
Sec. 141.2 Definitions.
* * * * *
Ground water under the direct influence of surface water means any
water beneath the surface of the ground with:
(1) Significant occurrence of insects or other macroorganisms,
algae, or large-diameter pathogens such as Giardia lamblia or
Cryptosporidium, or
(2) Significant and relatively rapid shifts in water
characteristics such as turbidity, temperature, conductivity, or pH
which closely correlate to climatological or surface water conditions.
Direct influence must be determined for individual sources in
accordance with criteria established by the State. The State
determination of direct influence may be based on site- specific
measurements of water quality and/or documentation of well construction
characteristics and geology with field evaluation.
* * * * *
3. In Sec. 141.52, the Table is amended by adding a new entry, in
numerical order, to read as follows:
Sec. 141.52 Maximum contaminant level goals for microbiological
contaminants.
* * * * *
------------------------------------------------------------------------
Contaminant MCLG
------------------------------------------------------------------------
* * * * *
(5) Cryptosporidium............................................. zero
------------------------------------------------------------------------
4. Section 141.71 is amended by revising the first three sentences
of paragraph (b)(2) introductory text to read as follows:
Sec. 141.71 Criteria for avoiding filtration.
* * * * *
(b) * * *
(2) The public water system must maintain a watershed control
program which minimizes the potential for contamination by Giardia
lamblia cysts, Cryptosporidium oocysts, and viruses in the source
water. The State must determine whether the watershed control program
is adequate to meet this goal. The adequacy of a program to limit
potential contamination by Giardia lamblia cysts, Cryptosporidium
oocysts, and viruses must be based on: * * *
5. Section 141.73 is amended by revising paragraph (d) to read as
follows:
Sec. 141.73 Filtration.
* * * * *
(d) Other filtration technologies. A public water system may use a
filtration technology not listed in paragraphs (a) through (c) of this
section if it demonstrates to the State, using pilot plant studies or
other means, that the alternative filtration technology, in combination
with disinfection treatment that meets the requirements of
Sec. 141.72(b), consistently achieves 99.9 percent removal and/or
inactivation of Giardia lamblia cysts and 99.99 percent removal and/or
inactivation of viruses and 99 percent removal of Cryptosporidium
oocysts between the source water and the first customer. For a system
that makes this demonstration the requirements of paragraph (b) of this
section apply.
6. Section 141.74 is amended by adding a new paragraph (d) to read
as follows:
Sec. 141.74 Analytical and monitoring requirements.
* * * * *
(d) Sanitary surveys for all systems. (1) A public water system
that uses a surface water source or a ground water source under the
influence of surface water shall be subject to an initial sanitary
survey by [insert date 5 years after publication of the final rule] and
a subsequent sanitary survey every five years [ALTERNATIVE: every three
years] thereafter.
(2) The sanitary survey shall be performed by either the State, or
an agent approved by the State. An agent approved by the State shall be
paid by the system. In exceptional circumstances, the State may approve
the public water system to conduct its own sanitary survey. In this
case, the public water system shall certify that the system conducted
the sanitary survey is in accordance with Sec. 141.2 and that the
sanitary survey report is true and accurate.
(3) If the State or an agent approved by the State is not available
to conduct the sanitary survey within the time frame specified in this
section, the system must conduct the sanitary survey. If an agent
approved by the State or the system itself conducts the sanitary
survey, the system must submit the sanitary survey report to the State
within 90 days of completing the survey and before the end of the five
year period.
Alternative A
7. Section 141.70 is amended by revising paragraph (a)(1) to read
as follows:
Sec. 141.70 General requirements.
(a) * * *
(1)(i) At least 99.9 percent (3-log) removal and/or inactivation of
Giardia lamblia cysts for systems serving fewer than 10,000 people. A
system serving 10,000 people or more must achieve a Giardia removal/
inactivation level by [insert date 18 months after publication of the
final rule in the Federal Register that depends on the concentration of
Giardia in the source water(s), as follows:
(A) If the source water(s) contains less than 1 cyst/100 liters,
the system must achieve at least 99.9 percent (3-log) reduction;
(B) If the source water(s) contains 1 to 9 cysts/100 liters, the
system must achieve at least 99.99 percent (4-log) reduction [OPTION:
99.9 percent (3-log) reduction];
(C) If the source water(s) contains 10 to 99 cysts/100 liters, the
system must achieve at least 99.999 percent (5-log) reduction [OPTION:
99.99 percent (4-log) reduction];
(D) If the source water(s) contains more than 99 cysts/ 100 liters,
the system must achieve at least 99.9999 percent (6-log) reduction
[OPTION: 99.999 percent (5-log) reduction].
(ii) Systems must achieve the required Giardia removal/inactivation
level, as specified above, between the source water and the first
customer. To calculate the Giardia density in source water from
monitoring data obtained during the sampling period specified by
Sec. 141.140 of this part, use the:
Option 1: Arithmetic mean of measured values.
Option 2: Geometric mean of measured values.
Option 3: 90th percentile value of measured values.
Option 4: Highest measured value.
* * * * *
Alternative B
8. Section 141.70 is amended by adding new paragraph (a)(3) to read
as follows:
Sec. 141.70 General requirements.
(a) * * *
(3) Beginning 18 months after promulgation of this rule, a system
serving 10,000 people or more must achieve a Cryptosporidium removal/
inactivation level between the source water and first customer that
depends on the concentration of Cryptosporidium in the source water(s),
as follows:
(i) If the source water(s) contains less than 1 oocyst/100 liters,
the system must achieve at least 99.9 percent (3-log) reduction
[OPTION: 99 percent (2-log) reduction];
(ii) If the source water(s) contains 1 to 9 oocysts/100 liters, the
system must achieve at least 99.99 percent (4-log) reduction [OPTION 1:
99.9 percent (3-log) reduction; OPTION 2: 99 percent (2-log)
reduction];
(iii) If the source water(s) contains 10 to 99 oocysts/100 liters,
the system must achieve at least 99.999 percent (5-log) reduction
[OPTION 1: 99.99 percent (4-log) reduction; OPTION 2: 99.9 percent (3-
log) reduction];
(iv) If the source water(s) contains more than 99 oocysts/ 100
liters, the system must achieve at least 99.9999 percent (6-log)
reduction [OPTION 1: 99.999 percent (5-log) reduction; OPTION 2: 99.99
percent (4-log) reduction];
Systems must achieve the required Cryptosporidium removal/
inactivation level, as specified above, between the source water and
the first customer. To calculate the Cryptosporidium density in source
water from monitoring data obtained during the sampling period
specified by section 141.140 of this part, use the:
Option 1: Arithmetic mean of measured values.
Option 2: Geometric mean of measured values.
Option 3: 90th percentile value of measured values.
Option 4: Highest measured value.
* * * * *
Alternative C
9. Section 141.73 is amended by adding a new paragraph (e) to read
as follows:
Sec. 141.73 Filtration.
* * * * *
(e) Public water systems that filter their source water must
achieve at least 99 percent (2-log) removal of Cryptosporidium between
the source water and the first customer.
Alternative D
10. Section 141.72 is amended by adding a new paragraph (c) to read
as follows:
Sec. 141.72 Disinfection.
* * * * *
(c) Public water systems that serve 10,000 people or more and use
either surface water or ground water under the direct influence of
surface water must achieve, by disinfection alone, at least a 0.5-log
inactivation of Giardia [ALTERNATIVE 1: 4-log inactivation of viruses].
Alternative E
11. No change in existing SWTR regarding level of removal/
inactivation requirements.
PART 142--NATIONAL PRIMARY DRINKING WATER REGULATIONS
IMPLEMENTATION
1. The authority citation for part 142 continues to read as
follows:
Authority: 42 U.S.C. 300f, 300g-1, 300g-2 300g-3, 300g-4, 300g-
5, 300g-6, 300j-4, 300j-9.
2. Section 142.16 is amended by adding paragraph (g) to read as
follows:
Sec. 142.16 Special primacy requirements.
* * * * *
(g) An application for approval of a State program revision that
adopts the requirement specified below must contain the following:
(1) The State must designate the method it will use to judge the
adequacy of watershed protection programs in minimizing the potential
for contamination by Giardia lamblia cysts, Cryptosporidium oocysts,
and viruses in the source water.
(2) The State must describe its criteria for the conduct of
sanitary surveys and the method it will use to judge the adequacy of
each sanitary survey. If the State elects to allow non-State personnel
to conduct the surveys, the State must specify the criteria to be used
to approve the non-State personnel. If the State intends to allow
public water systems to conduct sanitary surveys, the State must
specify procedures it will use for oversight and review of the surveys.
Alternative A
3. The following special primacy requirements are associated with
Alternative A from item 7, above.
(3) Section 141.70(a)(1). The State must demonstrate that it has in
place enforceable design and operating criteria for achieving the
levels of Giardia lamblia removal/inactivation required. Alternatively,
the State may institute a procedure for establishing design and
operating conditions on a system-by-system basis (e.g., a permit
system).
Alternative B
4. The following special primacy requirements are associated with
Alternative B from item 8, above.
(3) Section 141.70(a)(3). The State must demonstrate that it has in
place enforceable design and operating criteria for achieving the
levels of Cryptosporidium removal/inactivation required. Alternatively,
the State may institute a procedure for establishing design and
operating conditions on a system-by-system basis (e.g., a permit
system).
Alternative C
5. The following special primacy requirements are associated with
Alternative C from item 9, above.
(3) Section 141.73(e). The State must demonstrate that it has in
place enforceable design and operating criteria for achieving 2-log
removal of Cryptosporidium between the source water and the first
customer. Alternatively, the State may institute a procedure for
establishing design and operating conditions on a system-by-system
basis. (e.g., a permit system)
Alternative D
6. The following special primacy requirements are associated with
Alternative D from item 10, above.
(4) Section 141.72(c). The State must demonstrate that it has in
place enforceable design and operating criteria for achieving the level
of Giardia (virus) inactivation required. Alternatively, the State may
institute a procedure for establishing design and operating conditions
on a system-by-system basis (e.g., a permit system).
[FR Doc. 94-17650 Filed 7-28-94; 8:45 am]
BILLING CODE 6560-50-P
