EPA 811-Z-94-003
Friday
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
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
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.
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 die 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 nitration; 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; 401M 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,
401M 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, 401M 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
m. 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 denning 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 hi lieu
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38833
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(bJ(7)fC) 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)(l) 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
CTCR)(54 FR 27544; June 29,1989) and
the Surface Water Treatment Rule
(SWTRH54 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
(§ 141.71). The watershed control
program must TnfniTniy.fi 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 die 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
colifonn 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 (DBFs) 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 widi 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 tie 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
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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 DBFs 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 DBFs. 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 men 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. -f.
m. 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 apph'cable
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
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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/lOOL (geometric mean
4.45 cysts/lOOL), while
Cryptosporidium densities ranged from
0.13 to 48 oocysts/lOOL (geometric
mean 1.52 oocysts/lOOL). 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 (LeChavaluer 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/lOOL or more, while
about 45% contained 100 cysts/lOOL 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/
DBF 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 eriteroviruses 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/lOOL 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
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removal for different treatment
processes and disinfection conditions,
and (3) determine what, if any, changes
to the SWTR are needed to control
pathogenic viruses.
DBF Rule May Undermine Pathogen
Control
Some systems currently exceed the
required Giardia and virus reductions
specified by the SWTR. The DBF Rule
may potentially undermine pathogen
control in these systems by prompting
them to reduce DBF 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
lOOug/L to 75ug/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 DBF
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)
P/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.
EFA 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 rides.
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 1-1 .—PROPOSED D/DBP, ESWTR, ICR RULE DEVELOPMENT SCHEDULE
Time
line
Stater DBF rule
Stage 2 DBP rule
ESWTR
12/93
3/94
6/94
8/94
10/94
1/95
10/95
11/95
1/96
Propose required enhanced coagulation for
systems with conventional treatment.
MCLs-TTHMs (SOjig/l), HAAS (60ug/l),
bromate, chlorite. Disinfectant limits
Close of public comment period
Propose information collection require-
ments for systems>100k.
Propose Stage 2. MCLs for TTHMs (40 jig/
I), HAAS (30 (ig/l), BAT is precursor re-
moval with chlorination.
Promulgate ICR
Systems>100k begin ICR monitoring
SW systemsxIOOk, GW systems>50k
begin bench/pilot studies unless source
water quality criteria met.
Propose information collection require-
ments for systems >1 Ok.
Propose interim ESWTR for systems>10k.
Promulgate ICR.
Public comment period for proposed
ESWTR closes.
Systems>100k begin ICR monitoring.
Systems 10-100k begin source water
monitoring.
NOA for monitoring data, direction of in-
terim ESWTR.
Systems>10k complete ICR monitoring.
End NOA public comment period.
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38837
TABLE 1-1.—PROPOSED D/DBP, ESWTR, ICR RULE DEVELOPMENT SCHEDULE—Continued
Tlma
Una
State 1 DBP rule
Stage 2 DBP rule
ESWTR
3/96
12/96
6/97
10/97
12/97
6/98
12/98
6/00
1/02
Promulgate Stage 1 ....
Systems complete ICR monitoring
Effective. Effective for SW systems serving
greater>10k, extended compliance date
for GAC or membrane technology
Stage 1 limits effective for surface water
systems<10k, GW systems>10k
Stage 1 limits effective for GW
systems<10k unless Stage 2 criteria su-
persede
Notice of availability for Stage 2 reproposal
Complete and submit results of bench/pilot
studies.
Initiate reproposal—begin with 3/94 pro-
posal.
Close of public comment period
Propose for CWSs, NTNCWSs
Promulgate Stage 2 for all CWSs,
NTNCWSs.
Stage 2 effective, compliance for GAC/
membranes by 2004.
SystemsxlOOk complete ICR monitoring.
Promulgate interim ESWTR for
systemsxIOk.
Propose long-term ESWTR for
systems<10k, possible changes for
systemsxIOk.
Interim ESWTR effective for systems>10k.
1994-6 monitoring data used to deter-
mine treatment level.
Publish long-term ESWTR.
Long-term ESWTR effective for all system
sizes.
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 1-1 (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
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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
(Payer 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, hi 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)
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38839
indicated that inoculation with 100,
500, or 1,000 oocysts caused infection in
22,68, 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,
Leglonelh, 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 § 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 (§ 141.71(b)(2)). This
program must include a characterization
of the watershed hydrology
characteristics, land ownership, and
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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 § 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 he 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 § 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
§ 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 § 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 Oil-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 hi 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
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38841
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
Sotable and non-potable water supply
SPA, 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
FR1556, 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
(§ 141.75(b)(l)). 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 (§ 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,
§ 141.32(a) and § 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 § 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 dining the
month it becomes apparent that a
system will violate the monthly
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turbidity performance standard in
§ 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 § 141.73.
Pathogens may accompany the turbidity
particles that exit the niters, 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., Giaidia 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 »j
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:
Gm=log-' (l/nx[log Xi+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
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38843
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,
Cryptospondium 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, die 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. MCL6 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 4x10 - 3 and the
estimated lifetime risk of death was
about 3x10 ~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 7x10 ~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
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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 waterbome
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 7x10 ~s
(i.e., 10 ~4xlO ~2x70 years) lifetime risk
of death for certain subpopulations. The
7x10 -s 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:
No. ofgiardia/100L
<1 ...;
1-9
1 0-99
>99
Required treat-
ment level (per-
cent)
99.9 (3-loq).
99.99 (4-log).
99.999 (5-log).
99.9999 (6-loq).
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 DBF 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
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38845
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:
No. g!ardia/100L
•( 0-99
100-999
>1000
Required treat-
ment level (per-
cent)
99.99 (4-Iog).
99.999 (5-log).
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.
alternatives for Cryptosporidium, as
follows:
No. cryplosporidium/IOOL
<1
1-9
1 0-99
>99
Required treat-
ment level (per-
cent)
99.9 (3-log).
99.99 (4-log).
99.999 (5-log).
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-
No. cryptosporidium/100L
<1
1-9
10-99
>99
No. cryptosporidium/100L
<1 o
10-99
>99
Required treat-
ment level (per-
cent)
99 (2-log).
99.9 (3-loq).
99.99 (4-log).
99.999 (5-log).
Required treat-
ment level (per-
cent)
99 (2-loq).
99.9 (3-loq).
99.99 (4-loa).
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
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
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 nitration 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 mpre 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-lpg
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 die 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 § 141.2, Definitions;
§ 141.52, Maximum contaminant level
goals for microbiological contaminants;
§ 141.70, General requirements;
§ 141.71, Criteria for avoiding filtration;
and § 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
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
38847
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 HIE 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 HIE 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 § 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
(§ 142.15(c)(l)) 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
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38848
Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
risk assessment methodology developed
by Rose et al. (1991) and Grubbs et at
(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 1D/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 10 ~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 $85
per household per year in systems with
a median population of 5,500. As stated
above, EPA believes that smaller
systems should be able to use a more
economic treatment alternative than
additional disinfectant contact time.
EPA solicits comment on whether the
system level costs to achieve the
different log reductions indicated in
Table VI—2 by disinfection, or other
means, are reasonable and accurate.
Table VI-3 indicates the estimated
labor effort by the number of full time •
employees (FTEs), hours, and dollar
costs for States to implement the interim
ESWTR. If systems, rather than the
State, were to fund some or .all sanitary
surveys, then State costs would be
reduced accordingly. Further details of
this analysis are available in the
Regulatory Impact Analysis (EPA, 1994).
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38849
TABLE VI-1—ESTIMATED NATIONAL CONTACT BASIN COSTS FOR ENHANCED SWTR
System size category
4
2
3 M
4
5
Q
1
8
g „
1 o
\ 1
12.
Totals:
Interim Rute (Sys-
tems >1 OK).
Long-Term Rute (All
Systems).
population
per system
25-100
101-500
501-1 K
1K-3.3K
3.3K-10K
10K-25K
25K-50K
50K-75K
75K-100K
100K-5QOK
500K-1M
1M+
Cost estimates based on additional disinfectant contact basin size1
Number of affected systems
Filtering systems
W/out
soft
493
454
415
586
627
291
167
77
63
88
22
9
716
3,290
W/SOft
8
13
47
61
104
67
42
24
7
24
5
1
170
404
Total
501
467
462
647
731
358
209
101
70
112
27
10
887
3,694
Total capital cost (M$)
Filtering systems
W/out
soft
22
42
86
200
360
330
340
230
250
620
600
460
2830
3,540
W/soft
0.5
1.4
12
24
72
94
110
92
37
230
170
97
831
941
Total
23
43
98
224
432
424
450
322
287
850
770
557
3661
4,481
Total annualized cost (M$)
Filtering systems
W/out
soft
4
8
16
25
45
34
36.
24
26
67
64
50
302
401
W/soft
0.09
0.3
2
3
9
10
12
10
4
25
18
11
88
103
Total
4
8
18
28
54
44
47
34
30
92
83
60
391
504
' Cost estimates were developed on the basis of the following assumptions: 1) 35 percent of surface water systems currently meet ESWTR in-
activaUon 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), tio: UCOMIC.! = 0.7,
temperature - 5 "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 SWTR2
Cat#
•j
2
«
A
5
g
y
9
m
•jg
Median pop.
57
225
750
1,910
5,500
15,000
35,000
60,000
88,100
175,000
730,000
1,550,000
Total household costs, $/hh/yr3
Filter"
Min
360
170
88
36
27
11
7.9
6.6
6.1
5.1
3.5
3.1
Avgi
420
200
120
52
28
15
12
10
8.8
8.5
6.7
6.0
Max
960
450
310
110
67
40
30
26
24
24
20
18
Filter and Soften4
Min
430
200
110
43
30
13
10
8.8
7.5
6.6
4.7
4.2
Avgi
500
240
150
59
34
19
15
13
12
11
9.1
8.2
Max
1,100
540
350
130
85
49
39
34
32
33
27
24
* Costa assume that 35 percent of systems currently meet ESWTR requirements (LeChevallier et al., 1991) and therefore do not require con-
2Assumes Gtardta 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 cuatomer calculated according to the G/arrf/a infectivity dose response curve of Rose etal. (1991).
a Household costs represent costs for affected systems. Minimum costs are based on costs for systems requiring additional 0.5 log inactivation
whila maximum costs are based on requiring an additional 3-log inactivation. Average costs are based on distribution of costs for achieving dif-
ferent Inactlvatlons based on data by LeChevallier et al. (1991).
ture
softening
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
TABLE VI-3.—INTERIM ENHANCED SURFACE WATER TREATMENT RULE STATE PROGRAM COSTS MODEL
Variable
Regulation Adoption and Program Develop-
ment.
Review Plans and Specs
Log Removal Determination
Subtotal (x)
Staff Training (Rule Specific)
Sanitary Surveys3
Total
Averaae Annual Cost over 3.5 vears2
Default assumptions
0.5 FTE per State
10 days/large system
3 days per surface water system
1 0 days per technical FTE=f (x)
5 days/lg. sysVsurvey; 2 days/sm. sys./sur-
vey.
1
112
19
0
79
National burden
InFTEs
28.0
1N/A
19.0
47
2.1
78.7
128
37
In hours
47,040
1N/A
31,958
78,998
3,591
132,147
214,736
61.353
Cost
$1,540,000
1N/A
1,046,250
2,586,250
117,557
4,326,250
7,030,057
2.008.588
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
DBFs 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),
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
38851
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
die 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 ESWTRj considering the nature
ofmicrobialrisk.
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
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38852
Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
pathogen risk that the ESWTR must
address.
The accounting difficulty of sorting
between microbial and DBF 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 DBF
treatment requirements simultaneously.
In that case, the microbial and DBF-
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
optibns indicated in Section HIE aboye,
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'br 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:
2997
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
2998
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
2999
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
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules 38853
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.0.12875.
Enhancing Intergovernmental
Partnerships, and E.0.12866,
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 au 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/
DBF 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.
• (ffl.C) Rationale for setting MCLG of
zero and a treatment technique for
Cryptosporidium
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
• OIl.D.l) 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)
• (HI.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 (§ 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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Hypokalemic myopathy induced by
Giardia lamblia. N. Engl. J. Med. 330(1):66.
AWWA. American Waterworks Association
(1992). Jackson County Oregon
cryptosporidiosis outbreaks: January-June
1992. Summary, Expert Meeting, August 3,
4,1992.
AWWA. American Water Works Association
(1993). Officers & Committee Directory.
AWWA, Denver.
Bailey SW, and EC Lippy (1978). Should all
finished water reservoirs be covered.
Public Works for April 1978. P. 66-70.
Bennett JV, SD Holmberg, MF Rogers and SL
Solomon (1987). Infectious and parasitic
diseases. Am J Prev Med 3:102-114. In:
RW Amler and HB Dull (eds), Closing the
gap: the burden of unnecessary illness.
Oxford University Press, Oxford.
Berger PS, S Regli and L Almodovar (1992).
Cryptosporidium control in drinking water.
Am Water Works Assoc Proceedings, 1992
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Annual Conf, Mgmt and Regs, pp 845-864.
American Water Works Association,
Denver.
Cnsomoro DP and FB Jackson (1984).
Hypothesis: cryptosporidiosis in human
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9:153-158.
Casemore DP (1990). Epidemiological aspects
of human cryptosporidiosis. Epid Infec
104:1-28.
CDC Centers for Disease Control (1982).
Cryptosporidiosis: assessment of .
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Morbidity and Mortality Weekly Report 31:
589-592.
Clancy JL (1993). Interpretation of
microscopic participate analysis data—a
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Technology Conference Proceedings, 1992,
II: 1831-1844. American Water Works
Association, Denver.
Craun G (1991). Causes of waterborne
outbreaks in the United States. Wat Sci
Technol 24:17-20.
Craun GF (1993). Conference conclusions. In:
(GF Craun, ed.) Safety of Water
Disinfection: Balancing Chemical and
Microbial Risks. International Life Sciences
Inst Press, Washington.
Craun G (1994). Memorandum from G. Craun
to U.S. Environmental Protection Agency
(P. Borger), dated 1/19/94. Waterborne
outbreak data 1981-90, community water
systems.
Cromwell JE, Zhang X, Letkiewicz FJ, et al.
Analysis of potential tradeoffs in regulation
of disinfection by-products. Office of Water
Resource Center. Washington D.C. EPA-
811-R-92-O08.1992.
Current WL, NC Reese, JV Ernst, WS Bailey,
MB Hoyman and WM Weinstein (1983).
Human cryptosporidiosis in
immunocompetent and immunodeficient
persons. New Eng J Med 308(21): 1252-
1257.
D'Antonio RG, RE Winn, JP Taylor, et al.
(1985). A waterborne outbreak of
cryptosporidiosis in normal hosts. Ann.
Intern. Med. 103:886-888.
De Mol P, S Mukashema, J Bogaerts, W
Hemelhof and J-P Butzler (1984).
Cryptosporidium related to measles
diarrhoea in Rwanda. Lancet 2(8393): 42-
43.
EPA. Environmental Protection Agency
(1983). Assessment of Microbiology and
Turbidity Standards for Drinking Water.
EPA 570-9-83-O01. Washington, DC.
EPA. Environmental Protection Agency
(1989a). Regulatory Impact Analysis:
Benefits and Costs of Final Surface Water
Treatment Rule, prepared by Wade Miller
Associates, Inc., February 17,1989,
Washington, DC.
EPA. Environmental Protection Agency
(1989b). Cross-connection Control Manual.
EPA 570/9-89-007. Washington, DC.
EPA. Environmental Protection Agency
(1991a). Guidance Manual for Compliance
With the Filtration and Disinfection
Requirements for Public Water Systems
Using Surface Water Sources. Washington,
DC
EPA. Environmental Protection Agency
(1991b). Manual of Small Public Water
Supply Systems. EPA 570/9-91-003.
Washington, DC.
EPA. Environmental Protection Agency
(1991c). Manual of Individual and Non-
Public Water Supply Systems. EPA 570/9-
91-004. Washington, DC
EPA. Environmental Protection Agency
(1992). Consensus method for determining
groundwaters under the direct influence of
surface water using microscopic particulate
analysis (MPA). EPA 910/9-92-029.
EPA. Environmental Protection Agency
(1993). Drinking Water Criteria Document
for Cryptosporidium (Draft). Office of
Science and Technology (Office of Water),
EPA, Washington, DC.
EPA. Environmental Protection Agency
(1994). Regulatory Impact Analysis of
Proposed Interim Enhanced Surface Water
Treatment Rule (Draft). Office of Ground
Water and Drinking Water.
Ernest J, B Blagbum, D Lindsay and W
Current (1986). Infection dynamics of
Cryptosporidium parvum (Apicomplexa:
Cryptosporidiidae) in neonatal mice (Mus
musculus). J Parasitology 72(5):796-798.
Fayer R, and BLP Ungar (1986).
Cryptosporidium spp. and
cryptosporidiosis. Microbiol. Rev. 50:458-
483.
Gerba, C, and J. Rose. (1990). Viruses in
source and drinking water. Chap.18, pp
380-396. In: G. McFeters (ed), Drinking
Water Microbiology. Springer-Verlag, New
York.
Glass RI, JF Lew, RE Gangarosa, CW LeBaron
and M-S Ho (1991). Estimates of morbidity
and mortality rates for diarrheal diseases in
American children. J Pediatrics 118: 27-33.
Grubbs WD, Macler B. Regli S. (1992).
Modelling Giardia occurrence and risk.
EPA-811-B-92-005. Office of Water
Resource Center. Washington D.C.
Haas CN, JB Rose, C Gerba, S Regli (1993).
Risk assessment of virus in drinking water.
Risk Analysis 13: 545-552.
Harrington, W.A., Krupnick, A.J., and
Spofford, W.O.Jr.. The Benefits of
Preventing an Outbreak of Giardiasis Due
to Drinking Water Contamination.
Resources for the Future, 1616P Street,
NW., Washington, DC. September, 1985.
Hayes EB, TD Matte, TR O'Brien, TW
McKinley, GS Logsdon, JB Rose, BLP
Ungar, DM Word, PF Pinsky, ML
Cummings, MA Wilson, EG Long, ES
Hurwitz and DD Juranek (1989). Large
community outbreak of cryptosporidiosis
due to contamination of a filtered public
water supply. New Eng J Med 320:1372-
1376.
Herwaldt BL, GF Craun, SL Stokes and DD
Juranek (1991). Waterborne disease
outbreaks, 1989-1990. In: CDC
Surveillance Summaries, Morbidity and
Mortality Weekly Report: 40(SS-3): 1-21.
Hurst C (1991). Presence of enteric viruses
in freshwater and their removal by
conventional drinking water treatment
process. Bull World Health Org. 69 (1):
113-119.
Keswick, BH, et al (1985). Inactivation of
Norwalk virus in drinking water by
chlorine. Appl. Environ. Microbiol. 50:
261-264.
Korich DG, JR Mead, MS Madore, NA
Sinclair and CR Sterling (1990). Effects of
ozone, chlorine dioxide and
monochloramine on Cryptosporidium
parvum oocyst viability. Appl Environ
Microbiol 56:1423-1428.
Korich D, M Yozwiak, M Marshall, M
Arrowood, N Sinclair, and C Sterling
(1992). Cryptosporidium viability:
assessment and correlation with
infectivity. Water Quality Technology
Conference Proceedings, 1991,1:65-74.
American Water Works Assoc, Denver.
LeChevallier MW, DN Norton and RG Lee
(1991a). Occurrence of Giardia and
Cryptosporidium spp. in surface water
supplies. Appl Environ Microbiol 57:
2610-2616.
LeChevallier MW, DN Norton and RG Lee
(1991b). Giardia and Cryptosporidium spp.
in filtered drinking water supplies. Appl
Environ Microbiol 57:2617-2621.
Levine WC and GF Craun (1990). Waterborne
disease outbreaks, 1986-1988. In: CDC
Surveillance Summaries, Morbidity and
Mortality Weekly Report 39(SS-1): 1-13.
Lew JF, RI Glass, RE Gangarosa, IP Cohen, C
Bern and CL Moe (1991). Diarrheal deaths
in the United States, 1979 through 1987. A
special problem for the elderly. J Am Med
Assoc 265: 3280-3284.
Lopez et al. (1980). Waterborne giardiasis: a
communitywide outbreak of disease and a
high rate of asymptomatic infection. Am J
Epid 112:495-507.
Macler BA and S Regli (1993). Use of
microbial risk assessment in setting US
drinking water standards. Int J Food
Microbiol 18: 245-256.
Miller RA, MA Bronsdon and WR Morton
(1990). Experimental cryptosporidiosis in a
primate model. J Infect Dis 161: 312-315.
Moore AC, BL Herwaldt, GF Craun, RL
Calderon, AK Highsmith, and DD Juranek
(1993). Surveillance for waterborne disease
outbreaks—United States, 1991-1992.
Morbidity and Mortality Weekly Report:
42(SS-5): 1-22.
Payment, 1981. Isolation of viruses from
drinking water at the Point-Viau water
treatment plant. Can. J. Microbiol. 27:417.
Payment P, M Trudel, et al., (1985).
Elimination of viruses and indicator
bacteria at each step of treatment during
preparation of drinking water at seven
water treatment plants. Appl. Environ.
Microbiol. 49:1418-1428.
Payment P, L Richardson, J Siemiatychi, R
Dewar, M Edwardes and E Franco (1991).
A randomized trial to evaluate the risk of
gastrointestinal disease due to
consumption of drinking water meeting
current microbiological standards. Am J
Publ Health 81: 703-708.
Regli S, JB Rose, CN Haas and CP Gerba
(1991). Modeling the risk from Giardia and
viruses in drinking water. J Am Water
Works Assoc 83 (11): 76-84.
Regli S, JE Cromwell, X Zhang, AB
Gelderloos, WD Grubbs, F Letkiewicz and
BA Macler (1993). Framework for decision
making: EPA perspective. In: (GF Craun,
ed.) Safety of water disinfection: Balancing
chemical and microbial risk, pp 487-538.
International Life Sciences Institute Press,
Washington, DC.
Rendtorff RC (1954). The experimental
transmission of human intestinal
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protozoan parasites. II. Giardia lamblia
cysts given in capsules. Am J Hyg 59: 209-
220.
Rose JB, CN Haas and S Regli (1991). Risk
assessment and control of waterborne
giardiasis. Am J Publ Health 81: 709-713.
Smith HV, RWA Girdwood, WJ Patterson, et
al. (1988). Waterborne outbreak of
cryptosporidiosis. Lancet 2:1484.
Sobsey MD, F Takashi, and RM Hall (1991).
Inactivation of cell-associated and
dispersed Hepatitis A virus in water. J Am
Water Works Assoc 83 (11): 64-67.
Williams, F (1985). Membrane-associated
viral complexes observed in stools and cell
culture. Appl. Environ. Microbiol. 50:523-
526.
Wittenberg DF, MM Miller and J van den
Ende (1989). Spiramycin is not effective in
treating Cryptosporidium diarrhea in
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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-l, 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:
§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 § 141.52, the Table is amended
by adding a new entry, in numerical
order, to read as follows:
§ 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:
§ 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:
§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
§ 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:
§ 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 § 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 die 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)(l) to read as
follows:
§ 141.70 General requirements.
(a) * * *
(l)(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
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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
§ 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:
§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:
§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:
§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-l, 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:
§ 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)(l). 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)
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Federal Register / Vol. 59, No. 145 / Friday, July 29, 1994 / Proposed Rules
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 ofGiardia
(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-SO-P
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