Monday
July 1, 1991
Part XII
Environmental
Protection Agency
40 CFR Parts 141, 142, and 143
National Primary Drinking Water
Regulations; Final Rule
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30266
•t f, ,T/1 *"*',.*'-*'• ' • ' j i • 5 ' 1 '
Federal Register / Vol. S&'NO. 126 '/ Monday, 'july l.'l99J'/ Rules and''Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 141,142 and 143
BIN 2040-AA5S
[FRL-3960-1]
Drinking Water, National Primary
Drinking Water Regulations;
Monitoring for Volatile Organic
Chemicals; MCLGs and MCLs for
Atdlcarfo, Aldlcarb Suifoxlde, Aldicarb
Sulfone, Pentachlorophenol, and
Barium
AGENCY: Environmental Protection
Agency (EPA).
ACTION: Final rule.
SUMMARY: In this notice. EPA is revising
monitoring requirements for eight
volatile organic contaminants (VOCs)
originally promulgated July 8,1987. This
change synchronizes requirements for
these eight VOCs with monitoring
requirements for VOCs promulgated on
January 30^1991 (56 FR 3526). EPA is
also promulgating the MCLGs and MCLs
for aldicarb, aldicarb sulfoxide, aldicarb
sulfone, pentachlorophenol, and barium.
This Notice also corrects errors and
clarifies certain issues in the final rule
promulgating 33 National Primary
Drinking Water Regulations
promulgated January 30,1991 (56 FR'
3526).
EFFECTIVE DATE: The amendments to
§ 141.6, paragraph (c) of the table in
i 141.12, and § 141.62(b)(l) are effective
July 1.1991. The amendments to
§§ 141.11(b), 141.23,141.24.142.57.
143.4(b}(12) and (b)(13), are effective
July 30.1992. The revisions to
§ 141.32(e)(16}, (25) through (27) and (46);
S 141.50(a)(15). (b)(4). (b)(5) and (b)(6);
1141.51(b)(3); 1141.61(c)(2). (c)3, (c)(4)
and (c)(16); § 141.62(b)(3) are effective
January 1,1993.
The barium information collection
requirements of § 141.23 are effective
January 1,1993, if the information
Collection Request is cleared by the
Office of Management and Budget
(OMB). If not, EPA will publish a
document delaying the effective date of
the barium information collection
requirements. Otherwise, the
requirements will be effective when
OMB clears the request at which time a
document will be published in the
Federal Register establishing the
effective date.
In accordance with 40 CFR 23.7, this
regulation shall be considered final
Agency action for the purposes of
judicial review at 1'p.m.. Eastern time on
July 15.1991.
ADDRESSES: A copy of the public
comments received, EPA responses, and
all other supporting documents
(including references included in this
notice) are available for review at the
U.S. Environmental Protection Agency
(EPA), Drinking Water Docket, '401M
Street, SW., Washington, DC 20460. For
access to the docket materials, call 202-
382-3027 between 9 a.m. and 3:30 p.m.
Any document referenced by an MRID
number is available by contacting Susan
Laurence, Freedom of Information
Office, Office of Pesticide Programs, at
703-557-4454.
Copies of health criteria, analytical
methods, and regulatory impact analysis
documents are available for a fee from
the National Technical Information
Service (NTIS), U.S. Department of
Commerce, 5285 Port Royal Road,
Springfield, Virginia 22161. The toll-free
number is 800-336-4700. local: 703-487-
4G50.
FOR FURTHER INFORMATION, CONTACT:
Al Havinga, Standards Division, Office
of Ground Water and Drinking Water
(WH-550). U.S. Environmental
Protection Agency, 401M Street. SW.,
Washington. DC 20460, 202/382-5555.
General information may also be
obtained from the EPA Drinking Water
Hotline. The toll-free number is 800/426r-
4791, Alaska and local: 202/382-5533.
SUPPLEMENTARY INFORMATION:
Table of Contents
L Statutory Authority
0. Regulatory Background
III. Explanation of Today's Action
A. VOC Monitoring Requirements
1. Standardized Monitoring Framework
2. Sampling Points
3. Initial and Repeat Base Monitoring
Requirements
4. Increased Monitoring
5. Vulnerability Assessments and Waivers
B. Aldicarb, Aldicarb Sulfoxide. and
Aldicarb Sulfone
1. Aldicarb, Aldicarb Sulfoxide. and
Aldicarb Sulfone MCLGs
2. Aldicarb. Aldicarb Sulfoxide. and
Aldicarb Sulfone MCLs
C Pentachlorophenol
1. Pentachlorophenal MCLG
2. Pentachlorophenol MCL
D. Barium
1. Barium MCLG
2. Barium MCL
E. 1415 Variance Option
F. Analytical Methods
G. Corrections to the January 30,1991
Notice
IV. Economic Analysis
A. Regulatory Impact
B. Regulatory Flexibility Analysis
, C. Paper Work Reduction Act
I. Statutory Authority
The Safe Drinking Water Act ,
("SOWA" or "the Act"), as amended in
1986 (Pub. L. 99-339,100 Stat. 642),
requires EPA to publish "maximum
contaminant level goals" (MCLGs) for
contaminants which, in the judgment of
the 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 [allow] an adequate
margin of safety" (see section
.
At the same time EPA publishes an ,
MCLG. which is a non-enforceable
health goal, it must also promulgate a
National'Primary Drinking Water
Regulation (NPDWR) which includes
either (1) a maximum contaminant level
(MCL), or (2) a required treatment
technique (section 1401(1), 1412(a)(3),
and 1412(b)(7)(A)). A treatment -r
technique may be set only if it is not
"economically or technologically
feasible" to ascertain the level of a
contaminant (sections 1401(1) and •-
1412(b)(7)(A)). An MCL must be set as
dose to the MCLG as feasible (section
1412{b)(4)). Under the Act,- "feasible"
means "feasible with the use of the best
technology, treatment techniques and
other means which the Administrator
finds are available, after examination
for efficacy under field conditions and
not solely under laboratory conditions
(taking cost into consideration)" (section
1412(b)(5)). NPDWRs also include
monitoring, analytical and quality
assurance requirements, specifically,
"criteria and procedures to assure a
supply of drinking water which
dependably complies with such
maximum contaminant levels *
(section 140l(l)(D)). Section 1445 of
SOW A also authorizes EPA to
promulgate monitoring requirements.
fl. Regulatory Background
On July 8, 1987 EPA promulgated
NPDWRs for eight volatile organic
contaminants (VOC rule. 52 FR 25690).
On May 22. 1989 EPA proposed VOC
monitoring requirements for 10 •
contaminants and MCLGs and MCLs for
38 contaminants including aldicarb,
aldicarb sulfoxide, aldicarb sulfone,
pentachlorophenol, and barium. The
MCLGs and MCLs for these five
chemicals were reproposed on January
30, 1991 (58 FR 3600) at different levels
due to information which was received
and/or analyzed by the Agency ',
subsequent to the May 22. 1989
proposal.
The monitoring requirements outlined
in today's rule for the most part mirror
(with several exceptions, as noted t
1 below) the VOC requirements publisher.
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Federal Register / yo!. S6..No. tap'/. Mo«d«y..|tdy
Rules abd Regulation 30267
i January 30.1991 for the 10 VOCa in
the Phase II rule. EPA stated in the
reproposal that changes to the proposal
incorporated in the final rule would
apply to monitoring requirements for
both the 10 VOCs promulgated January
30,1991 and the 8 VOCs included in
today's rule. This ensures the monitoring
requirements for the IB VQCs (the 8
Phase I VOCs and the 10 Phase II VOCs)
remain identical Consequently, the
changes published today will also apply
to the monitoring requirements for the 10
Phase D VOCs published January 30,
1991.
in Explanation of Today's Action
A. VOC Monitoring Requirements
1. Standardized Monitoring Framework
In response to comments received on
the May 22,1939 Phase U proposed rule.
EPA developed a standardized
monitoring framework to address the
issues of complexity, coordination
between various regulations, and
synchonization of monitoring schedules.
EPA stated that this framework would
serve as a guide for future source-
related monitoring requirements
adopted by&he Agency.
Comments submitted to EPA during
the comment period revealed support for
the standardized monitoring framework.
Within this standardized framework
each State must designate
approximately one-third of the systems
to conduct initial monitoring during each
year of the initial compliance period (Le.
one third in 1993, one-third in 1994 and
one third in 1995). This arrangement is
intended to level the anticipated
workload.
Most commenters believed that the
framework does achieve the goals of
. synchronization of monitoring
schedules. Most comments recived by
the Agency addressed specific issues
related to changes in the VOC
monitoring requirements and how the
1987 VOC requirements will be
coordinated with the Phase II
requirements promulgated January 30,
1991.
The monitoring requirements outlined
in .today'* rule for the most part mirror
(with several exceptions as discussed
. below) the VOC requirements
promulgated in January 1991 for 10
VOCs. EPA stated in the proposal for
today's rule that if comments and
information received during the
comment period result in changes to this
proposal, EPA will promulgate a final
rule which will also apply to monitoring
requirements, for the 10 VOCs
promulgated on January 30. This ensures
that the monitoring requirements for the
18 VOCs (the 8 Phase I and 10 Phase II
VOCs) remain WeaticaL Consequently.
the changes promulgated today will also
apply to the monitoring requirements for
the 10 VOC* published January 30.1991.
2. Sampling Points
In the proposal EPA staled that the
Agency had received information
suggesting that petroleum and
hazardous material spills and leaks
have contributed to drinking water
contamination in systems using plastic
pipe, EPA stated that it is concerned
about this issue because this
contamination typically occurs after the
designated sampling point and
consequently would not be defected. As
a result EPA proposed in $141.24 (f) (1)
and (2) that "if conditions warrant the
State may designate additional sampling
points within the distribution system or
at the consumer's tap, which more
accurately determines consumer
exposure."
Most comments received on the
proposed change to the sampling points
opposed the concept. Objections raised
by commenters addressed three major
issues: (1) Whether the SDWA granted
EPA the legal authority to require
sampling at the consumer's tap; (2)
permeation of plastic pipe typically
occurs in service tines and thus is
generally within the consumer's control;
and (3) the Agency failed to specif}' best
available technology to address this
problem. While not agreeing with these
comments, the Agency has decided to
give further consideration to options
addressing the issue of VOC permeation
• of plastic pipe. Accordingly, EPA has
dropped this proposed monitoring
provision in the final rule. As noted
above, because the Agency intends that
the VOC monitoring requirements are
identical, this decision to withdraw the
changes in the sampling points will also
apply to the final rule published January
30.1991. The Agency intends to address
this issue in a subsequent rulemaking
seeking additional information and
solutions to the permeation issue.
3. Initial and Repeat Base Monitoring
Requirements
In the VOC regulations promulgated
in July 1987. distinctions in base (or
minimum) requirements were made
between ground and surface water
systems, system* which have more than
or less than 500 service connections, and
vulnerable/non-vulnerable systems. In
streamlining the requirements. EPA
proposed that all systems (regardless of
system size) take four quarterly samples
each compliance period. After the initial
round of four quarterly samples, all
systems which do not detect VOCs in
the initial round of quarterly sampling
would monitor annually beginning in the
next calendar year after quarterly,
sampling is completed. Ground water
systems which conducted at least three
years of annual and/or quarterly
sampling; and did not detect any VOCs
would bit allowed to reduce the :
sampling frequency to a single sample
every thiee yearsV EPA also proposed
that systems could grandfather sampling
results from the Section 1445 monitoring
for unregulated contaminants for the
initial compliance period even if only
one sample rather than 4 quarterly
samples were analyzed in the initial
compliance period.
EPA received several comments ,"
disagreeing with the requirement that
systems (lake four quarterly samples
during the initial compliance period.
These commenters cited the regulatory
impact oil small systems and non-
transient ! water systems. In addition, one
comment^r suggested that "cse" should
be considered in determining the initial
sampling frequency. Another commenter
stated that increasing the sampling
frequency to annual (rather than every 3
years) was a major policy shift and
would have an adverse impact on small
systems.!
EPA continues to believe that 4
quarterly samples are necessary to ,
establish a baseline of analytical results
for any V[OCs which occur with
sufficient frequency. However, we note -
that because .all systems must have
completed their initial round of
monitoring by January 1992 under
existing requirements in 1141.24{g)
(monitoring for 8 regulated
contaminants) and § 141.40 (monitoring
for unregulated VOC contaminants), the
initial mo|nitoring requirements (i.e., 4
quarterly samples) will only apply to
new systems or those systems which
have a new source. Most systems will
be able to begin annual monitoring in
January 1993 if the initial sampling
results are grandfathered. We feel that-
•initial sampling frequency based upon
"use" is riot practical or protective of
public health because available
occurrence data indicate that VOCs are
found in virtually all geographic areas in
the United States.
4. Increased Monitoring
In the 1987 VOC rule, systems which
detect VC)Cs (defined as any analytical
result greater than 0.0005 mg/1) were
required to monitor quarterly. Several
comment 3rs believed that this
regulator/ minimum detection limit was
too low and should alternately be 50% or
80%ofthi2MCL.
EPA ncjtes that the 0.0005 mg/1
requirement has been in effect since the
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30203 Federal Register / Vol. 56. No. 126 / Monday* July.1. 1991, / Rufes and Regulations
1907 VOC rule. This requirement serves
to give early Indication that
contamination has occurred before a
violation occurs. EPA acknowledges
that false positives might rarely occur
(i.e., less than one percent of the time]
with a detection limit of 0.0005 mg/1.
However, we note that requirements in
§ 141.24 (f)(13) also allow the State to
require confirmation samples for
positive or negative results. In addition.
the State baa the option to delete results
of obvious sampling errors. EPA
believes that States have sufficient
discretion to address the issue of false
positives through these provisions.
Another commenter argues that
waivers will be difficult to obtain
because of unreasonably low detection
Htsits. EPA regulations do not allow
systems which have detected VOCs to
receive waivers because even detecting
contamination is evidence that the
system is vulnerable. This
contamination should be further
examined by additional monitoring.
Several commenters objected to the
provision which allows States to reduce
the sampling frequency of systems
which detect contamination. One
commenler believed that this
determination should not be made for
ground water systems until four quarters
of monitoring have elapsed. EPA
believes that the proposed requirement
that the State determine the system is
"reliably and dependably" below the
MCL is protective of health. The two
quarter requirement is sufficient as a
minimum standard but we note that
there may be situations where
additional monitoring (beyond the two
quarter/four quarter minimum) will ba
* necessary to establish a baseline. In
these cases, if the State does not make
the "reliably and dependably"
determination, systems will be required
to continue to monitor quarterly.
5. Vulnerability Assessments and .
Waivers
Most commenters agreed with the
concept of vulnerability assessments
and waivers particularly the provision
for a separate vulnerability decision by
consideration of use and susceptibility.
Several commentero noted that the shift
of responsibility from States to water
systems to conduct vulnerability
assessments could result in waivers
being unavailable for small systems.
Several commenters stated that
additional guidance was necessary to
ensufe systems know how to conduct
vulnerability assessments.
As stated in the proposal EPA shifted
the responsibility to conduct
vulnerability assessments from States to
water systems because we believe that
these assessments are part of the :
systems' monitoring responsibilities. In
addition, previous comments indicated
that State resource constraints
precluded the conduct of vulnerability
assessments. Consequently, EPA shifted
the responsibility to conduct
vulnerability assessments to water
systems. EPA agrees with the
commenters that additional guidance on
how to conduct vulnerability
assessments is needed and is currently
developing such guidance. This guidance
will be completed and made available to
water systems and States prior to the
compliance period which begins January
1.1993.
Our goals ere to efficiently utilize
State and PVVS resources and to be
consistent with Phase n monitoring
requirements. EPA believes that today's
rule furthers these goals.
B. Aldicarb, Aldicarb Sulfoxide and
Aldicarb Sulfone
1. Aldicarb, Aldicarb Sulfoxide and
Aldicarb Sulfone MCLGs
On January 30,1991 EPA reproposed
MCLGs for aldicarb, aldicarb sulfoxide,
and aldicarb sulfone at 0.001,0.001, and
0.002 mg/kg/day. The MCLG for each of
the three chemicals was based on a
revised RfD adopted in August 1990 that
reflected non-cancer endpoints of
toxicity, cholinesterase inhibition
(ChEI)" and. for the parent compound
(aldicarb), clinical signs in animals (soft
mucoid stool and diarrhea) and humans
(nausea, vomiting and diarrhea in some
sensitive individuals were noted in
epidemiological data). Cancer
classification is Group D (inadequate
human evidence of carcino'genicity).
Public Comments
EPA has previously addressed the
public comments received in response to
the proposals of November 13,1985 and
May 22,1989 in the Federal Register
notice of January 30,1991 (56 FR 3600).
Four commentera responded to the
January 19S1 proposal. One commenter
argued that EPA's RID of 0.0002 mg/kg/
aldicarb MCLG it legally and
scientifically uniupportable. In support
of this position, the commenter cited the
May 23,1990 recommendation of the
joint study group of the Agency's
Science Advisory Board and Scientific
Advisory Panel (SAB/SAP) that ChEI is
' not an adverse effect and therefore
should not be the basis of EPA
regulation for aldicarb. One commenter
advised that the Agency establish the
MCLG and MCL for aldicarb and the
sulfoxide metabolite based on the
Haines (1971) human study. This
commenter suggested using the NOAEL
for clinical signs in this study, 0.05 mg/
kg. and a 10-fold uncertainty factor (UF)
to establish the MCLG. For aldicarb
sulfone, this commenter indicated that,
the lowest dose tested in the one-year
dog feeding study (Hazleton Labs, 1987),
0.11 mg/kg/day, is the NOAEL and
should be used with a 10-fold UF to
establish the MCLG for aldicarb sulfone.
Two additional commenters agreed
with the position expressed by the first
commenter relative to the SAB/SAP
recommendation on ChEI as only a
marker of exposure, and that the Agency
should not lower the RfD for aldicarb.
However, one of these two commenters
noted that the MCLG should be based .
on child exposure.
A fourth commenter indicated that the
reproposed MCLGs for aldicarb,
aldicarb sulfoxide, and aldicarb sullone,
based on the revised RfD of 0.0002 mg/
kg/day, may not provide a sufficient
margin of safety against acute toxic
symptoms in the general population at
levels as low as 0.0011 mg/kg/day.
The first commenter also noted that
establishing an MCLG based on ChEI is
inconsistent with the Agenby regulation
for fluoride and silver.
Response to Public Comments
Aldicarb and aldicarb suifoxide. The
Agency reproposed an MCLG of 0.001
mg/1 for aldicarb and aldicarb sdfoxide
based on a revised RfD of 0.0002 mg/kg/
day (July, 1990), as described in the
January 30,1991 Notice (56 FR 3604).
This RfD was based on clinical effects
and cholineslerase inhibition (ChEI) in
animals and humans following exposure
jo aldicarb. The Agency sought public
comment on considering both clinical
signs and ChEI in setting the RfD and, in
turn, the MCLG.
Many of the studies considered in the
risk assessment for both aldicarb and
aldicarb sulfoxide reported ChEI in
.exposed humans or animals.
Consideration of blood ChEI as an
adverse effect has been and remains
controversial among the scientific
community. ChE may be significantly
inhibited in the blood without apparent
signs of impaired functiont histologjcal
damage or other clinical effects in
exposed individuals. There are
instances, though, where low levels ot
ChEI are observed along with clinical
manifestations. A more detailed
discussion of the levels of ChEI for the
studies considered in the risk ..
assessment of aldicarb and its sdfe»*
is given in the January 30.1991 Notice. •
The Agency agrees with the public
comments in that blood ChEI can be
considered as a biomarker of exposure-
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However, to be protective of public
health, the Agency considers that ChEI
can not be totally discounted in the risk
assessment for aldicarb, aldicarb
sulfoxide, and aldicarb sulfone. The
Agency is currently evaluating the
correlation between ChEI and clinical
signs of toxicity. If the conclusions of
this evaluation alter the basis presented
for the MCLG in this notice, then the
Agency will initiate a process for
determining whether the MCLG should
be revised. Thus, after consideration of
public comments, the Agency has
decided to base the final MCLG for
aldicarb, aldicarb sulfoxide. and
aldicarb sulfone, on clinical signs. ETA
will continue to examine the relevance
of using ChEI in establishing an MCLG.
Over a period of time this effort is
expected to resolve the questions
related to the significance of ChEI.
Because the controversy has not yet
been fully resolved, EPA developed an
alternative approach for setting the
MCLG.; using clinical signs.
Since both the Agency-verified RfD
and the alternative derivation of the
MCLG result in an MCLG value of 0.001
mg/1, the Agency is promulgating the
MCLG at this level. An MCLG of 0.001
mg /I will be sufficiently pro tective of
public health. ,
The final MCLG of 0.001 mg/1 is based
on signs of clinical toxicity in dogs and
humans exposed to aldicarb. The
quantitative assessment stems from a
no-effect level for clinical effects of 0.02
mg/kg/day as determined in a 1-year
dog study (Hazelton Labs. Inc., 1988). At
higher doses, effects such as diarrhea
and soft stools were observed. The
Agency has determined that these sighs
are representative of clinical signs of
toxicity. In keeping with general Agency
practice (56 FR 3532). an uncertainty
factor of 100 was used to account for a
no-effect level from an animal study that
considers intra- and interspecies
differences in response to toxicity. The
resulting value, 0.0002 mg/kg/day, is
numerically the same as the RfD which
considers both clinical effects and ChEI.
This was adjusted by the assumption of
a 70 kg adult drinking an average of 2
liters water per day and a relative
source contribution of 20% to yield an
MCLG of 0.001 mg/1.
The no-effect level of 0.02 mg/kg/day
and resulting MCLG of 0.001 mg/1 is
supported qualitatively by a controlled
human study (Haines, 1971) and takes
into consideration the observation
reported in the Goldman study (1990). In
the Haines study, no significant clinical
effects were observed in four healthy
males given doses of 0.025 or 0.05 mg/
kg/day. A higher dose of 0.1 mg/kg/day
resulted ir neurological effects. The no-
f'Vrh. 56|fcNb.
'Reslutoiong
effect level of 0.05 mg/kg/day was not
used as the sole basis for the MCLG
because of the limited scope of the study
such that a sensitive population may not
have been studiedi and the narrow
range between the no-effect level and
the effect level. Moreover. Goldman et
al. reported clinical effects at estimated
doses lower than those reported by
Haines. •
Goldman el al. reported clinical
effects in humans (including women and
children) following three separate
incidents involving aldicarb/aldicarb
sulfoxide in California. Exposure to
aldicarb sulfoxide from the
contaminated watermelons and
cucumbers were estimated to range from
0.002 to 0.08 mg/kg body weight. A low
effect level for clinical effects was
estimated at 0.002 mg/kg. This study is
not used as the sole basis for the MCLG.
however, since the authors noted that
the dosage calculations were uncertain
and because of the wide range of human
sensitivity demonstrated by these
individuals. The authors relied on self-
reports of food consumption, estimates
of weight consumed and estimates of
body weight
Although each of the studies has
•limitations, as described above, the
Agency-has determined that the dog and
human studies taken together support
the calculation of an MCLG of 0.001
mg/1.
1 In summary, the Agency is
promulgating an MCLG of 6.001 mg/1 for
aldicarb and aldicarb sulfoxide based
on a weight of evidence of clinical signs
of toxicity observed in humans and
animals.
Aldicarb sulfone. -
The Agency reproposed an MCLG of
O.OC2 mg/L for aldicarb sulfone in the
January 30,1991 notice. This level was
based on a no-observed-adverse-effect
level for ChEI in blood of 0.1 mg/kg/day
and an uncertainty factor of 300.
Information on clinical .effects in the
study was not reported
Aldicarb sulfone is considered less
toxic than the parent based on a 25-fold
difference in acute toxicity; the LDM for
the sulfone is 25 mg/kg/day compared
to the LEbo for aldicarb of 1 mg/kg/day.
No data are available to determine
clinical effects or chronic toxicity
associated with exposure to aldicarb
sulfone. As stated above, the Agency is
currently evaluating the correlation
between ChEI and clinical signs of
toxicity. Thus, the Agency will not use
the MCLG of 0.002 mg/L proposed for
the sulfone in the reproposal. Rather, to
be protective of public health, the
Agency is promulgating the MCLG of
0.001 mg/L established for aldicarb and
aldicarb sulfoxide, based on clinical
signs of| toxicity as a surrogate for the
sulfone.] If the conclusions of the Agency
evaluation of ChEI alter the basis for the
MCLG, then the Agency will initiate a
process fo'r determining whether the
MCLG for aldicarb sulfone should be
revised.! • ' -
In surrimary. the Agency is
promulgating an MCLG of 0.001 mg/1 for
aldicarb sulfone.
2. Aldicarb, Aldicarb Sulfoxide. and
Aldicarb Sulfone MCLs
The proposed MCLs for aldicarb,
aldicarb sulfoxide, and aldicarb sulfone
were based upon an analysis of several
factors including: (1) The effectiveness
of the best available technology (BAT—
granular activated carbon) in removing
aldicarb, aldicarb sulfoxide, and
aldicarb sulsfone to levels at or below
the proposed MCLs of 0.003 mg/1; (2) the
feasibility (including costs) of applying
BAT for large systems. EPA estimated
that the cost to remove aldicarb,
aldicarb sulfoxide and aldicarb sulfone
using GAG to be $10-14 per household
and thus feasible; and (3) the
performance of analytical methods as
reflected in the practical quantification
level (PQL) for each contaminant. In the
proposed notice EPA stated that data
from Water Supply Studies showed that
the PQIls for aldicarb, aldicarb -
.sulfoxide, and aldicarfa sulfone could be
set at 0.003 mg/1 by broadening the
acceptance limits to ±55%.
The pivotal comments concerned '
establishing the PQL for aldicarb,
aldicarb sulfoxide, and aldicarb sulfone.
One coinmenter noted that Water
Supply Studies *22-25 which were used
to calculate the PQL did not "bracket"
the proposed levels. This commenter
noted that the lo\vest levels in Water
Supply Studies #22-25 were 0.00947 mg/
1 for aldicarb, 0.00867 mg/1 for aldicarb
suifoxide, and 0.00033 mg/1 for aldicarb
sulfone,! Several commenters objected to
EPA's adjustment of PQL acceptance
limits to achieve lower MCLs. These
commenters noted that the usual Agency
practice; is to use ± 20% or ± 40% of the
true value. These commenters objected
to the Agency's broadening the
acceptance limits to ± 55% arguing
instead that EPA should use a single
fixed acceptance limit.
After considering the comments, EPA
decided to revisit the rationale on which
the PQI-s were based. As a result, the
Agency concluded that the elements of
the rationale that involved extrapolating
data were inappropriate for this
compound:
EPA set the proposed PQLs of 0.003
rrg/1 by extrapolating from the lowest
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•30270
Fedefcat Register /; Vol 58,.No, 12S /"Monday. Jdy l./199t /.fades and.Regulations
levels fa Water Sapply Studies £22-25
to the point at which. 75. perceof of the
participating laboratories, woaM be aWe.
lo «aaijfze withstk 4-55. percent ef, (he
true value. EPA-ueedlhis.extrapolation
technique-became the Water Supply
Studies £22-25 study designs did not
Include the levels of concern, i-e.,
MCLGs of 0.001 and 6,002- mg# proposed
lo the January 1991 Notice (5S FR 3606).
The existing Water Supply Studies
were, designed to provide data for
assessment of laboratory performance
at levels of concern which were higher
(I.e., M€LGs.of oeOffrag/l proposed in
November 1583 650.FR 469861 and °-01
nndO.04 mg/1 proposed in-May 1989 (54
lH 22Q8QJ): 1m thfc ea«ev the le»eb
evaluated ta the. Water Supply Studies
were above the: lexicological levels of
concern (.O001 mg/3J foe aWicarb,
n'dicarb- suMbxide and aldicarb sutfone
c,s proposed in January. 1331. F«c this
reason we dtcised to uae an-ahemate
procedure for setting the PQLfor
fildicarb.. which seta the PQL at five
times the in terkboeatory method
detection timjt (IMDL), was first
discussed inaettingtiie MCLfor vinyl
chloride (52.FR 25690; July 1987), This
procedure tensed tcrsel th« PQL when
there is not water supply study data at
the level of concern or wheft the usual
proceedure would resttU is a- PQL which
poses a greater than 1O-4 cancer risk.
The aldicarbvaldicarb suifoxide and
aldicarb solfone PQLs were determined
using the range of 5 to 10 times the
DvlDL. The PQLs of OOQ3.8.004 and 0.002
mg/1 for aldtcatb. aldicarb suifoxide and
aldicarb sulfone. respectively. artbased
on the lower factor of 5 times-the
respective IMDL»{Jjj^ 0.0005.0-.0008 and
0.0003 mg/1). EPA has previously stated
(i.e., EDB (SB FR 3528))! that the use of 5
times the IMDL-instead e£ 10 times the
MDL to set the PQL may be appropriate
when- other considerations suggest the
PQL shouldTje lower(i.e., where there is
a lack of performance evaluation data at
the level of concern for * particular
contaminant). In the case of aldicarb
and its metabolites, the Agency ha*
decided to base thePQLoa-5 times the
IMDL because (a} it is feasible and (b).it
is closer to the MCLG" than the. 10
multiplier. •
The validation study for Method 5314.
(the approved method for Ae aldicarbs)
provides evidence that • PQL of. 3.0 nig/1
is achievable-foraldtearb. The desiga
for this study IB e«raparable-to-that «f
the-Water Supply Studies. (Le~ unknown
concentrations, reagent grade water-
collaborative). The level of 0.003 rag/I
(3,24 ug/1, was analyzed for aldicarb. in
the study and resulted in good-precision
and accuracy with a mean recovery of
3.24 jig/1 and a standard1 derratioa of
0.33 fig/LResalts of analysea Sot
aldicarb salfoxide and aWkarb-sttBbne
also had good precision and accuracy
but the. levels analyzed? were-at levels of
6.40 and 644 jtg/1,-respectively, H'A
believes that these method waJidatfon
results give additional support for the
PQLs.
EPA recognizes that, at the PQLfevefe
chosen, slightly less precision, and!
accuracy will occur. However. EPA
believes that it is appropriate tb accept
less precision in orderta obtain more
stringent levels of controL Because of
the lack of performance evaluation
studies at the MCL& me acceptance
limits for aldicarb, aldicarb- snHoxide
and aldicarb sulfone witt be based on
two standard deviations nsiag-Water
Supply Study statistics. EPA will-
reevaluate this when it acquires the
appropriate data at levels below or at
the PQLs, from-ongoing-Water Supply
Study data to assess "fixed true value"
acceptance limits, EPA also believes
that the precision and accuracy at these
levels will improve after msss uae of the
relatively new methodology.
EPA has examined the health risks of
setting the KiCLs above the MCLGs of
0.001 mg/1. Children are the most
sensitive population for these
compounds. However, a child likely
would not consume a whole Eter at one
time. More typically children consume
water throughout the day and this would
mitigate against adverse effects at the
MCLs and below. The adverse effects of
aldicarb are thought to be reversible v
within 4 to 6 hours at higher levels of
exposure. Therefore, EPA believes that
the MCLs of 0.003 mg/1 for aldicarb,
0.004 mg/1 for aldicarb suifoxide and
0.002 mg/1 for aldicarb sulfone are
protective for children. Until the
analytical chemistry and laboratory
performance improve, EPA believes the
MCLs for aldicarb. aldicarb suifoxide.
and aldicarb sulfone are set at the
lowest level feasible. Consequently, for
the reasons cited above the MCL for
aldicarb, aldicarb suifoxide andafdlcarb
sulfone are established at 0.003 mg/L
0.004 mg/1 and 0.002. mg/L respectively.
C Peatachloropheno]
1. Pentachlorophenol BJCLG
On January 30.1991. EPA proposed an
MCLG of zero, based on * drinking.
water contaminant classification of
Category I for pentachloropheaofc GPGPJ-
This proposal was boxed on the
classification of PCP as a Class B2
carcinogen under EPA's cancer
classification system (i.e.. probable-
human carcinogen). EPA. in reaching the
B2 classification, determined that there
is sufficient evidence of carckiogeaicity
for pentachlorophenol from- animal
studies.This decision was. supported by
me Science Advisory Board in April
1990. Two grades of pealachterophenoi
(purified commerdal and technical
grades) both induced multiple tamer
types- at different dose levels in male
and- female mice.
Summary of Comments
Three organizations submitted
comments oa the Agency's; carcinogen
classification for PCP. All three
commenters believe that the
carcinogenic evidence from' animal
studies is limited-These commenters
argued that PCP should be elassined in
Glass C (with- an MCLG of 02. mg/I)^
based on a National Toxicology Program
bioassay which, detected a response in-
only one species of B6C3F1 mice. These
commenters cited other negative roden*
studies. One commenter calculated the
cancer risk and claimed that EPA
overestimated the cancerrisk by a
factor of 10.
EPA's Response to the Comments
After careful review of the comments,
EPA reaffirmed that pentacHorophenbl
should be classified as B2 carcinogen
(probable human carcinogen). The
studies cited by the commenters were
previously considered by the Agency
and no new information was provided
by me commenter.
EPA's B2 classification is based on
inadequate human data and sufficient
evidence of carcinogenicity in animals:
statistically significant increases 5i the
incidences of multiple biologically
significant tumor types (hepatocellular
adenomas and carcinomas, adrenal
medulla pheochromocytomas and
malignant pheochromocytomas, and/or
hemangiosarcomas and hemangiomas)
in one or both sexes of B6C3F1 mice
using two different preparations of
penitachlorophenoL la addition, a nigh
incidence of two uncommon tumors
(hemangiomas/hemangiosarcomas and
adrenal medulla pheochromocytomas]
was observed with both preparations.
This classification is supported by
mutagenicity data, which provide some
indication that PCP has clastage&ic
potential. .
Several studies in rodents tited by
commenters- were unable to demonstrate
the carcinogenicity of PCP. However.
these studies were all judged by EPA to
be limited and not useful for drawing
conclusions concerning the
carcinogenicity of PCP. The study
reported by Innes et al (1969) used only
one dose with an insufficient number of
animals. The study by Catilina (198T)
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'Federal; Register ,'/ Vol. 58.'No'. 12& / Monday. July I.'l99l /'Rules' jand'Regulations
used an inappropriate route of '
administration with only one dose, and
there was excessive mortality. The
study by Schwetz et al. (1978) used an
inadequate number of animals, and it is
not clear whether the maximum
tolerated dose (MTD) had been met
Finally, the dose level, frequency and
duration of exposure were limited in the
study by Boutwell and Bosch (1959).
In quantifying the cancer risk. EPA
used pooled tumor incidence of
hemangiosarcoma/hemangioma,
pheochromocytomas and liver neoplasm ,
in the female mice to obtain a slope
factor of 0.12 per (mg/kg) /day. This
slope factor results in a unit risk of 3 X
10~* per fjig/1). This means an adult.
person who drinks 2 liters of
contaminated water per day for life (70
years), is expected to have an upper
bound cancer risk of 3 in a million at a
concentration of 1 fig/ 1 water. Thus, at
the proposed MCL of 1 fig/1, the upper
bound risk of cancer is within the 10"4 to
10~* range. The statement in the January
30 Federal Register (page 3508) that "A
cancer unit risk estimate of 4.76 E-08
cases/person (MS/1) /yr" should be
deleted."?
EPA Conclusion
EPA reaffirms the Class B2
classification for pehtachloropheno} and
places pentachlorophenol in drinking
water contaminant Category I.
Consequently, the MCLG is set at zero.
2. Pentachlorophenol MCL
The proposed MCL for
pentachlorophenol was based upon an
analysis of several factors including: (1)
The effectiveness of the best available
technology, granular activated carbon,
in reducing influent concentrations to
the proposed MCL of 0.001 mg/1 or less:
(2) the feasibility (including costs) of
applying BAT for large systems at
approximately S10 per household per
yean (3) the performance of available
analytical methods as reflected in the
PQL Data from Water Supply Studies
£22-25 indicated that the PQL could be
established at 0.001 mg/1 with an
acceptance limit of * 50%; and (4)
coparison of the individual lifetime.
carcinogenic risk of 3 X 10~* for the
MCL to EPA's target risk range of 10~* to
10" *. EPA requested comment on
whether the MCL should be established
: at a level below the 10~'risk level.
EPA received numerous comments on
the PQL. Commenters noted (1) that EPA
failed to identify the procedures it used
to derive the PQL: (2) that EPA
underestimated the analytical
variability at the MCL; and (3) that the
proposed MCL will yield unacceptably
large laboratory performance v
variability. Several organizations
commented on the question of whether
the PQL should be established at a level
below the 10/—6/;risk rangei-These
commenters stated (hat health risk
should not be part of the PQL
determination. Several commenters
noted that EPA has yet to establish a
. consistent approach to establishing
PQLs. These commenters stated that the
PQL should be determined
independently and not set to achieve an
MCL that is within EPA's acceptable
risk range. Several commenters stated
that they do not favor development of
MCLs below the 10/—8/ risk range. One
commenter argued that EPA should
establish the MCL at the 10/ -6/ risk
range (i.e., 0.0003 mg/1).
The procedures EPA used to establish
the PQL for pentachlorophenol are
similar to those used in the PQL
assessments for prior regulated
contaminants, i.e., the eight VOCs on
July 8,1987 (52 FR 25690) and 33
pesticides, VOCs and lOCs on January
30,1991 (56 FR 3526). The procedures
EPA uses to establish PQLa are
described in the July 8,1987 Notice on
pp. 25699-25700. EPA believes that its
establishment of the pentachlorophenol
PQL is consistent with its policy as
articulated in those prior Notices.
As stated in the January 1991
proposed rule, EPA in May 1989
estimated the PQL to be 0.001 mg/1,
which was based on 10 times the IMDL
because of the lack of Water Supply
Study data. EPA has previously used
this estimation technique for several
contaminants. This level is typically a
higher level than the MDL and
represents a practical and routinely
achievable level with reasonable
certainty that the reported value is
reliable. EPA subsequently received and
analyzed Water Supply Study data to
determine the proposed PQL with
accompanying acceptance limits.
Based on our reanalysis of the Water
Supply Study data, the Agency
concluded that the data did not support
the proposed PQL of 0.0001 mg/1. This
was evident by the erratic laboratory
performance for concentrations that
were less than 0.0001 mg/1.
Consequently, a revised PQL was
assessed using the procedures described
above. The pentachlorophenol PQL is
based upon the results of EPA and State
laboratory data from Water Supply
Studies #22-25. EPA calculated the -50
percent acceptance limits (i.e., true
value of the sample ±50 percent) based
upon these Water Supply Study
statistics. The "plus or minus percent of
the true value" acceptance limits were
derived taking into consideration the
expected precision and accuracy. This
range closeiy approximates the 95
percent confidence limit estimated from
the regression equation determined from
' the Wajter Supply Study data. EPA
believes a PQL is achievable if the ,
Water Supply Studies show that more
than 75j percent of the laboratories are
within the target range. In the case cf
pentaclilorophenol, the PQL was set at a
concentration where,at least 75 percent
of the EPA and State laboratories were
within the specified acceptance range. A
plot of the percent of laboratories
passing (within the ^50 percent
acceptance range) versus true .
concentration of the samples
demonstrated that the PQL should be set
at 0.00:1 mg/1. EPA subsequently
included data from Water Supply
Studied £2(5 and #27 in its analysis.
These ilata confirm that concentrations
equal to or greater than the PQL of 0.001
mg/1 with an acceptance limit oT ±50
percent provides a performance target
for laboratories that is achievable by 75
percent of (the EPA and State
laboratories.
'Several commenters noted that a -SO
percenlt acceptance limit will result in
unacceptable analytical variability
among laboratories. These commenters
argued that EPA must establish a lower
fixed acceptance range (i.e., ±20% or ±
40%). Though EPA agrees with these
conunijnters that a single fixed
acceptance limit is desirable, EPA has
not established these limits because (1)
many of the methods are relatively new
and require sophisticated equipment
and highly trained analysts which still
resultii in variable laboratory
performance and (2) the analysis of
Waterj Supply Study data demonstrates
that laborsto'ry performance can in fact
vary for some of the contaminants. As
labors tones gain experience with the
instrumentation and methodology, EPA
- anticipate:; improvements in laboratory
performance. EPA is continually
evaluating ongoing Water Supply Study
data a!s it becomes available. These
evaluations help determine whether the
accep tance limits for reg-Jated
contaminants should be amended as -
laboratory performance improves.
As indicated previously, several
commenters stated that they do not
favor establishing MCLs below 10/—6/
risk. This view is consistent with the
Agency's policy of setting drinking
water standards within the 10/—4/ to
10/— IS/ lifetime risk range. In response
to the commenter who supported setting
the MCL for PCP at 0.0003 mg/1 (i.e.. 10/
—6/ lifetime risk), we note this
regulatory level is not feasible at this
time liecause it is less than the PQL of
0.001 nsjt/L
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36272 Federal Register / Vol. 56. No. 126 / Monday. Jufr 1. 1991 / Rales and Regulations
D. Bariunt
l.BsrimnMCLG *
In May. 1989-EPA proposed aa MCLG
of 5 mg/l based upon the Wones et al.
(1087) human clinical study which failed
to delect adverse effects at 10.0 mg/l.
EPA applied tn uncertainty factor of 2
to derive an MCLG of 5 mg/1.
Subsequent to the May, 1989 proposal
the Agency adopted aa RfD of 0.07 ing-/
kg/day which was based on the Wones
1990 study (an update of the Wones 1987
study). This RfD was adjusted for the
use of 1.5 liters per day in the study by
using a NOAEL of 7.5 Eg/1 rather than
the proposed 10,0. mg/L In addition, the
uncertainty factor changed from 2 to 3.
. The MCLG was. calculated as follows:
(0.07 mg/fcg/d«yK?0 kg)
2 mere/day
Z« mg/l
«vHch wa* rounded to 2 mg/l. EPA did
not factor the relative source
contribution into this calculation since
the basis for the RfD is a human study in
which contributioiift from food and air
were taken into account
EPA received four comments from the
public concerning- the, proposed. 2 mg/l
barium MCLG; afi were opposed. One
comraenter argued that EPA was
unreasonably conservative when it used
an uncertainty factor (UF) of 3 in the
calculations that were used to determine
the proposed 2 mg/l barium MCLG. This
comment recommended an MCLG of 10'
mg/l baaed on the use of an UF of 1.
Other comments recommended a higher
MCLG, based on the use of an UF of 2.
Two commenters. argued mat EPA
should not have mathematically
rounded down hi the calculations that
were used to arrive at the proposed 2
mg/L MCLG. Rather, this commentsr
recommended that EPA mathematically
round up to yield an MCtG of 3 mg/L
One commenter argued that EPA should
set separate standards for insoluble
(e.g., barium suifate) and soluble barium
compounds («.&, barium chloride)
because the toxicity of mess two
species la different
EPA realizes that there are valid
arguments for an UFless than 3. Prior to
the 2 mg/l proposal In January 1991, EPA
considered an UFof 2. EPA believes that
the UF «houM reflect the uncertainty in
the data base—the greater the
uncertainty in the data base, the greater
the UF that should be used to detemine
the MCLG. That is, the greater .the
uncertainty about the human toxicity of
a chemical, the more cautious the
Agency should be in determining the UF.
In EPA's judgment, the uncertainty in •
the relerant barium data base is sach aa
to require an UFof 3.Thus, EPA
disagrees with those who tecornmemd an
UF less than 3, .
EPA policy is fa use the "rounded"
RfD value in its calculation of the
MCLG. In this case, the MCLG
calculation noted previously based on
the Agency RfD of 0.07 mg/kg/day
yields an MCLG of 2.45 mg/l. This value
is then rounded to a single significant
figure of 2 mg/L
We agree that an aqueous suspension
of relatively insoluble barium suifate is-
much less toxic than a- nohition- of
relatively soluble barium chloride.
However, we do not believe that this
fact is relevant to the MCLG
determination. All' available evidence
indicates that at the same dissolved
level in drinking water (Le.,. mg/l
dissolved barium), one barium salt
should present the same toxicity as .the
other. Once dissolved in water,, the
barium ions produced by barium sulfafe
or barium chloride are indistinguishable
and thus so is the resulting- taxicity.
Thus EPA disagrees with the
recommendation that separate
standards should be set for soluble, and
insoluble barium compounds.
For the reasons stated above, EPA
continues to place barfam to Category
III and promulgates an MCLG of Z mg/l.
2. Barium MCL
The current barium MCL of 1 mg/l
was promulgated in 1975 (40 FR 50570}.
EPA notes the proposed MCL would
raise the level from 1 mg/l to 2 mg/l.
EPA continues to believe me current
standard is feasible and consequently
believes the revised standard of 2 mg/l
is likewise feasible. Consequently, the
MCL for barima is promulgated: as
proposed at 2 mg/L
E. 1415 Variance Option ,
In the proposal EPA stated that there
may be some water supplies that serve
more than 1^00 people (500 service
connections) but fewer than. 3,300 people
(1.000 service connectJoms) that face
high compliance costs. Consequently.
EPA proposed an option to allow
variances to those systems not eligible
for additional exemptions beyond the
initial three-year exemption (Le^
systems serving more than 1400 people
but fewer than 3.300 people): EPA is not
finalizing that proposal today but
instead may repropose thi* option in- the
future.
F. Analytical Methods
In the January 30,1991 notice, EPA
cited an improvement to EPA Method
525 evaluated by the EPA
Environmental Monitoring and Support
Laboratory (56 FR 3550). The improved
method uses C-18 LSE discs as well as
the C-18 LSE cartridges. In addition.
EPA noted in the January 30 notice that
several commenters complained about
the use of diazomethane as the
esterifying agent in Method 515.1 for 2,4-
D, 2.4JJ-TP, and pentachlorophenol.
While EPA laboratories have used this
reagent safely for years, EPA agreed
that this is a matter of concern. In the
January 'notice, EPA recommended that
in the interim those laboratories that do
not wish to use diazomethane can use
the derivation procedure in the packed
column methods currently cited in 40
CFR 141.24{f) fpr2,4-D and 2,4.5-TP.
Pentachlorophenol can be analyzed by
Method 525.
EPA has received several comments
which questioned whether the
procedures cited above (i.e.. the disq.
cartridge for Method 525 and the
derivation procedure for Method 515.1)
are approved as EPA methods. EPA is
removing this ambiguity by citing
revised methods dated May, 1991 which
allow the use of these procedures.
G. Corrections to the January 30,1931
Notice •
This notice also corrects errors
contained in the January 30,1991 Notice
(56 FR 3S26) and adds clarifications to
the regulatory language. These
corrections and clarifications are
described below.
In s\141.12(c) the maximum •
contaminant level for total
trihalo'methanes is changed from 0.1 mg/
1 to 0.10 mg/l.
In i 141^3{a)(4)(i) EPA has added
language to clarify that a system which
composites samples can use the original
sample. It is not necessary for the
system to retake the sample when
contaminants are detected
In 5 141.23(i)(l) EPA added the word
"method" in the last sentence to clarify
which detection level applies for
calculation of samples below zero.
In { 141.23fk)(l) the date in footnote 4
for "Methods for Determination of
Inorganic Substances in Water Fluvial
Sediments" is changed from 1985 to
1989. Also in (kXl), Method 27O3 is
deleted from the approved list of
methods. EPA discussed deleting this
method on page 3548 of the January 30,.
1991 notice.
In S 141.23(k)(2) Method 20Q.7a,
Inductively Coupled Plasma, was an
approved method and is added.
The table in §. 141.23(k)(4)' which lists
holding times for mercury is changed to
read 28 days for plastic and glass. This
is consistent with Table 17 on page 3549
of the January 30,1991 Notice.
• S1
§
tl'
s'-
A-G
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Federal Register /Vol. 56. No. 126 / Monday. July 1. 1991 / Rules Bind Regulations 30273
In § 141.23(k)(5)(ii), the second nitrate
in the table with an acceptance limit of
±15 percent >0.4 mg/1 is changed to
nitrite ±15 percent >0.4 mg/1.
Revisions to $ 141.23 Inorganic •
Chemical Sampling and Analytical
Requirements inadvertently eliminated
inorganic sampling and analytical
requirements for the 9 inorganics .listed
in § 141.11. EPA is reinserting the
previous inorganic monitoring and '
, analytical requirements by adding
paragraphs (1) through (q) to § 141.23
(previously 1141.23 (a) through (e)). This
correction has the effect of retaining the
previous inorganic requirements for
cadmium, chromium, mercury, nitrate.
and selenium until July 30.1992; for
barium until January 1.1993: and beyond
July 30,1992 for arsenic.
Any alternate test procedures
previously approved under § 141.27 for
both inorganic and organic
contaminants continue to be effective
until July 30.1992 and January 1.1993.
for barium.
In 5141.24{e), Method 505 can also be
used to analyze For endrin and is added
to the list of acceptable methods.
In 5141.2*{h){8) the sentence "After a
maximum of four quarterly samples
show the system is in compliance * * *"
is changed to read "After a minimum of
four quarterly samples show the system
is in compliance * * *" (emphasis
added). The reference to paragraph
(h)(12) is changed to (h)(ll).
In § l41.24(h){12Kiv) toxaphene is
added to the list of contaminants which
can be analyzed using EPA Method 508.
In § 141.24{h)(13)(ij the reference to
paragraph (h)(13) is changed to
paragraph (h)(12).
The laboratory certification
requirements for the pesticides were not
included in the final rule. In
§ 14L24(h){19) EPA is including
laboratory certification requirements.
The performance requirements were
discussed and listed on pages 3550 to
3552 of the January 30,1991 Notice.
In § 141.62(b) the MCL for fluoride is
changed from 4 mg/1 to 4.0 mg/1.
In § 141.57(b) the reference to
§ 141.52(h) should be changed to
§141.62(b).
In the footnotes to § 143.4 (12) and (13}
the updated versions of the methods
should have been cited. In footnote 4.
EPA Method 20O7. version 3.1. April ,
1990 is changed to version 3.Z August.
1990: In footnote 5, EPA Method 200.6.
version 4.1. March 1990, is changed to
version 4.3, August 1990; in footaote 6. ,
EPA Method 200.9, version 1.0. April
1990, is changed to version 1.1. August
1990.
In § 143.4(12) a later version of the
method is cited. EPA changes Method I-
305J-84 to Method 1-3051-85.
In § 143.4(13) a later.version of the
method is cited. EPA changes Method I-
3720-84 to 1-3720-85.
IV. Economic Analysis
Executive Order 12291 requires EPA
and other regulatory agencies to perform
a regulatory impact analysis (RIA) for
all "major" regulations, which are
defined as'those regulations which
impose an annual cost to the economy
of $100 million or more, or meet other
criteria. The Agency has determined
that the proposed rule is a minor rule for
purposes of the Executive Order. This '
regulation has been reviewed by the
Office of Management and Budget as
required by the Executive Order and
any comments they make will be
available in the public docket
In accordance with the Executive
Order, the Agency previously conducted
an assessment of the benefits and costs
of regulatory alternatives as part of the
Phase II rule which was promulgated in
the January 30.1991 Federal Register.
This assessment in the Phase II rule , '
determined the impacts of this
regulation as part of the Phase II rule
and consequently these impacts are not
separately reconsidered in this notice.
A. Regulatory Impact
EPA's analysis conducted under the
proposed rule for 38 contaminants (54
FR 22062, May 22.1989) indicates that
approximately 37fi systems would
violate the aldicarb MCL of 0.003 mg/1
based on the uncertainty in the data
base. EPA does not believe MCLs of
0.004 mg/1 for aldicarb sulfoxide and
0.002 mg/1 for aldicarb sulfone will
change this estimate. An additional 825 .
systems would violate the MCL for
pentachlorophenol.
One commenter provided information
disputing EPA's estimate of the 378
systems which would violate the MCLs
for aldicarb. aldicarb sulfoxide and
TABLE 1.—REGUIATO«Y IMPACT
a!dicarb[sulfone. This commenter noted
the relative lack,of occurrence data to
estimate!regulatory impact. This .
commenter assumed 1% of the systems
(654 systems) would exceed the MCL for
aldicarb [which is almost double the EPA
estimate! EPA acknowledges the
uncertainty in determining the
regu!atoi[y impact and stated in the ,
Proposed Notice that ±50% of its
estimate of 378 system's (189 to 587)
systems may violate the MCL Though it
is conceivable that 854 systems may
violate the aldicarb MCL. EPA points
out that (he recently completed National
Pesticide Survey did not detect aldicarb
in any well fit levels exceeding 0.00071
mg/1. I . ' . ; " - ' •
Several coKimenters stated that EPA
.should consider the impact of these
regulatory requirements on the
collateral effects which trickle down
through cither regulatory programs such
as Superfund, the Clean Air Act (CAAJ.
stream water quality standards under
the Clean Water Act and requirements
under the Resource Conservation and
Recovery Act (RCRA). While EPA
acknowledges that these secondary
impacts may occur, the purpose of
today's action is solely to establish
drinking water standards that public .
water systems must comply with.
Consequently, EPA does not consider
the cost of secondary impacts which .
may occiir under the CAA. Superfund. or
RCRA. One ccmmenter also noted that
these secondary impacts also affect the
water supply industry by increasing the
waste and disposal costs of treatment.
EPA is aware of this issue and did
include the cost of disposal in the
Regulatory Impact Analysis
accompanying the January 30,1991 final
rule. !
As staled earlier, EPA did not
reconsider the costs for the proposed ,
VOC monitoring requirements because
those costs were considered in the final
Phase II iiile promulgated on January 30,
1991. The' cos ts of today's VOC
monitoring requirements have virtually
no impact on the total cost of VOC
monitoring primarily because a single
analytical method can analyze a range
of contaminants. Sampling for ell VOC
contaminants can be conducted at the
same time.
Coman-dunt
Aldicarb (including sulfcxide and su!'one)_ ' .
Penzachlofophenoi... . ...
Systems in
violation
"
378
625
Annual 1 Typical HH l treatment coct/system/year
cost
(Smittion/yi} 1
- $6.7 j
•19 i
.STOlH'
600
600
Medium'
39
39
targe «'-
10-14
10
-------
302/"4 ' Federal Register '/' Vol) 56, No. 126 / Monday, July 1. 1991 / Rules and Regulations
TABLE 1.—REGULATORY IMPACT—Continued
Contaminant
Birtufn « «..«. « .».«.««—« - - -
Systems in
violation
P.
Annual
treatment
cost
(Smillion/yr)
0
Typical HH ' treatment cost/system/year
Small'
» $230-460
Medium*
« $54-1 60
Urge4
•$26-110
i HH«houMtold,
* Sroill tfUwn serving 25-100 people. ' •
• Medrum system Monng 10,000-25.000 people. For Barium medium system serves 3,300-10,000 people.
4 Urge tytiwns s«rviog more man 1,000.000 people.
* Cost dependent upon BAT chosen.
We estimate that approximately
280,000 people will experience reduced
exposure to aldicarb, aldicarb sulfoxide
and aldicarb sulfone. Approximately
960,000 people will have reduced
exposure to pentachlorophenol.
B. Regulatory Flexibility Analysis
The Regulatory Flexibility Act
requires EPA to consider the effect of
regulations on small entities. 5 U.S.C,
602 etseq. If there is a significant effect
on a substantial number of small
systems, the Agency must prepare a
Regulatory flexibility Analysis which
describes significant alternatives which
would minimize the impact on small
entities. An analysis of the impact on
small systems due to the MCL for
aldicarb is included in the RIA which
supported the final Phase II rule
promulgated January 30,1991. The
Administrator has determined that the
proposed rule, if promulgated, will not
have a significant effect on a substantial
number of small entities.
C, Paperwork Reduction Act
The information collection
requirements in this 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 as part of the information
collection requirements supporting the
final Phase II rule on January 30,1991.
The information collection requirements
are, not effective until OMB approves
them and a technical amendment to that
effect is published in the Federal
Register.
List of Subjects in 40 CFR Parts 141,142,
and 143
Chemicals, Reporting and
recordkeeping requirements. Water
supply, Administrative practice and
procedure.
Dated: June 17,1991.
William K. Rellly,
Administrator, Environmental Protection
Agency.
For the reasons set forth in the
preamble, title 40 of the Code of Federal
Regulations is 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 and ,,
300J-9.
2. In § 141.6, paragraph (a) is revised
and paragraph (g) is added to read as
follows:
§ 141.6 Effective dates.
(a) Except as provided in paragraphs
(b) through (g) of this section, the
regulations set forth in this part shall
take effect on June 24,1977.
* • * * * . *
(g] The regulations contained in
Section 141.6, paragraph (c) of the table
in 141.12, and 141.62(b)(l) are effective
July 1,1991. The regulations contained in
§ § 141 .ll(b), 141.23,141.24.142.57(b).
143.4(b)(12) and (b)(13), are effective
July 30.1992. The regulations contained
in the revisions to §'§ 141.32(e](16). (25)
through (27) and (46); 141.50(a)(15),
(b)(4). (b)(5) and (b)(6); I4l.51(b)(3):
141.61(c)(2). (c)(3), (c)(4) and (c)(16);
141.62(b)(3) are effective January 1,1993.
3. Section 141.11 is amended by
revising the introductory text of
paragraph (b) to read as follows:
§ 141.11 Maximum contaminant levels for
Inorganic chemicals.
*****
(b) The Maximum contaminant levels
for cadmium, chromium, mercury,
nitrate and selenium shall remain
effective until July 30,1992: the
maximum contaminant level for lead
shall remain effective until December 7,
1992; the maximum contaminant level
for barium shall remain effective until
January 1,1993.
•*•*.*
4. In 5 141.12. paragraph (c) in the
table is revised to read as follows:
!
§ 141.12 Maximum contaminant levers for
organic chemicals.
(c) Total trihalomethanes (the sum of the
concentrations of bromodichlorometh-
ane, dibromochloromethano, tribromo-
methane (bromoform) and trichloro-
methane (chloroform)) .__U_
Level
milli-
grams
per liter
0.10
5. Section 141.23 which was published
January 30, 1991 (56 FR 3526) and which
will become effective July 30, 1992, is
amended by revising paragraphs (a)(4)(i)
(excluding the table) and (i)(l); revising
the .table in (k)(l); revising paragraph
(k)(2); revising the table in (k)(4);
revising the table in (k)(5)(ii); and
adding paragraphs (1). (m), (n), (o). (p).
and (q) to read as follows: ~
J 141.23 Inorganic chemical sampling and
analytical requirements.
* «'*'*,«
(a)**'
(4)***
(i) If the concentration in the
composite sample is greater than or . , :
equal to the detection limit of any
inorganic chemical, then a follow-up
sample must be analyzed within 14 days
from each sampling point included in the
composite. These samples must be
analyzed for the contaminants which
were detected in the composite sample.
Detection limits for each analytical
method are the following:
(!) For systems which are conducting
monitoring at a frequency greater than .
annual, compliance with the maximum
contaminant levels for asbestos, barium,
cadmium, chromium, flouride, mercury,
and selenium is determined by a running
annual average at each .sampling point.
If the average at any sampling point is
greater than the MCL, then the system, is
out of compliance. If any one sample
would cause the annual average to be
exceeded, then the system is out of
compliance immediately. Any sample
below the method detection limit shall
-------
-"•!•''' ' ' ' '
• Federal Register / Vol. 56.. Nq. 126 / Monday, jujy 1, J1991 /-Rules an^ $egulatioo8 30275
roe calculated at zero for the'purpose of
determining the annual average.
• * •• * *
(k) Inorganic analysis:
INORGANIC CONTAMINANTS ANALYTICAL METHODS
Contaminant
Methodology'
EPA'
Reference (.Method NoJ
ASTM »
SM»
Other
Asbestos.
Barium —
Cadmium.
Transmission Electron Microscopy
Atomic absorption: furnace technique
Atomic absorption; direct aspiration
(nductwefy-coupted plasma...
Chromium-
Mercury —
Nitrate
Atomic absorption: furnace-technique-
loductivetyicoupled piasma...
Atomic absorption; furnace technique __
Inductively-coupled plasma _.
Manual cold vapor technique
Automated cold vapor technique —
Manual cadmium reduction—.
Automated hydrazine reduction
Automated cadmium reduction
Ion selective electrode .._
Nitrite __
Ion Chromatography..^—...........
SpectrophotomeJric-.-
Selenium.
Automated cadmium reduction
Manuel cadmium reduction ..
ton Chromatography
Atomic absorption: gaseous hydride
Atomic absorption: furnace technique-
EPA»
208.2
208.1
200.7"
213.2
200.7A'
218.2
200.7 «••
245.1
245.2
3533
353.1
353.2
300.0
354.1
353.2
353.3
300.0
270.2
03223-86!
O3867-90
C3867-90!
D3867-90'
03867-90!
03659-68
3Q4
303C
304
304^
303F
418C
416F
418F
418C
304*
WeWWG/
5880 >
B-1011 '».
B-1011 I0
1 Methods of Chemical Analysis of Water and Wastes." EPA environmental Monitomg and Support Laboratory. Cincinnati. OH 45268 (EPA-600/4-79-020),
March 1983. Available from ORO Publications, CERI. EPA. Cincinnati. OH 45268. .
1 Annual Book of ASTM Standards. Vet 11.01 American Society for Testing and Materials. 1916 Race Street Philadelphial PA T9103.
» "Standard Methods for the Examination of Water and Wastewater," 16th edition. American Public Health Association. American Water Works Association, Water
Podution Control Federation, 1985. !
4 "Methods for Determination of Inorganic Substances in Water and Fluvial Sediments." Techniques of Water-Resourctts Investigations of Hie U.S. Geological
Survey Books, Chapter A1,1989. Open-fiie Report 85-495. Available from Open-Re Services Section, Western Distribution Etranch. U.S. Geological Survey. MS 306
Box 24525. Denver Federal Center. Denver. CO 80225. i
* -Orion Guide to Water and Wastewater Analysis." Form WeWWG/5880. p. 5.1935. Orion Research. Inc.. Cambridge. MA. -
« 200.7A "mducbvely-Coupted Plasma Atomic Emission Analysis of Drinking Water." Appendix to Method 200.7. March, 1567. U.S. EPA, Environmental Monitoring
and Support Laboratory, Cincinnati. OH 45268. i
1 The addition of 1 mL of 30% H-O, to each 100 ml of standards and samples a required before analysis.
• Prior to dilution of the Se calibration standard, add 2 mL of 30% HJD. for each 100 mL of standard.
•"Analytical Method for Detenwiation of Asbestos Fibers in Water." EPA-600/4-83-043. September 1983. U.S. EPX Eninronmental Research Laboratory.
Athens. GA 30613. i
10 "Waters Test Method for the Determination of Nitrite/Nitrate in Water Using Single Column Ion Chromatography, Method B-1011, MiJIipore Corporation, Waters
Chromatography Division, 34 Mapte Street. Milford. MA 01757. •
' 'For approved analytical procedures tor metals, the technique applicable to total, metals must be used. i
(2) Analyses for arsenic shall be
.conducted using the following methods:
Method l 206.2. Atomic Absorption
. Furnace Technique; or Method ' 206.3.
or Method « D2972-88B, or Method *
307A. or Method » 1-1062-65, Atomic
Absorption—Gaseous Hydride: or
Method »206.4. or Method 4 D-2S72-
88A, or Method * 307B,
SpectrophoJometric, Silver Diethyl-
dithiocarbiaraate: or Method 200.7A.
Inductively Coupled Plasma
Technique *.
* -Mtlboda of Chemical Analyst! of Water and
Wiitn." EPA Environmental Monitoring and
Bupoort Labontoiy. Cincinnati, Ohio 4S28B (EPA-
•00/4-79-020). March 1979. Available Crom ORD
Pubuution*, CQU. EPA, Cindnntti. Ohio 4SZB8. For
•pprarvd analytical procedure* for metals, the
Wehatqnt applicable to total metal* must be uaed.
* "Suuxiird Methods for the Examination of
Wkttr and Wattewater." MKh Edition. American
Public Health AuocUtioo, American Water Work*
Association. Water Pollution Control Federation.
1985.
* Technique* of W«ter-Re»ourc*» Investigation of
the United State* Geological Survey. Chapter A-t
"Methods for Detetmianlion of Inorganic
Subitance* in Water and Pluvial Sediment*." Book
S. 1970. Stock #014-001-03177-8. Available from
Superintendent of Documents. US. Government
Printing Office. Wiishington. DC 20402.
* Annual G'ook of ASTM Standards, part 31
Water! Amencan fiociety for Tetting and Material*.
1916 Race Stlwet. fhiladelphia. Pennsylvania 19103.
* Appendix to Method 20O7. March 1987. VS.
EPA. Environmental Monitoring System*
Laboratory. (Cincinnati. OH 4S268.
ContBmnant
ft It tltTt '
KmOtm 1
Kmtjnmpiit
Pknriite « ..,.., ,.. .
Mo^jryl ,.
Nitrate:
Chlorinated
Non-chlorinated ._ .
Nitnte
PrMorvativfl
Ccc< 4*C
Co" HOi lopM <$ :.., „.,..„„, , ,, ,..,
CM HO, la pM <5
Con HO, to pH <2
Nona .
Con HO, to pH <-2 ,
Cool. 4'C
Con H-SO. to pH <2
Cool 4'C
Contfiner *
Por G
Po»Q '
PorG .
PorG
PorG
p or G L
P or G . _
p or G
P or G ' . .i
Time*
6 months.
6 months.
1 month.
26 days.
28 days.
14 days.
1 48 hoars.
-------
Federal Register •/ 'Vol. 56; No. 126 / Monday.' Jdly' 1."-1991- /''Rules 'and!Regulations
Contaminant
Preservative
ConHNOjtopH <2.
Cbrrtainef *
P or G ...
6 months.
thouid bo added to sample. • • -
1 P«D>asbc. hard or soft G«g!ass. hard or soft. _ - .
* In aM cases samples »hQuW be analyzed as soon after collection as possible.
({)«••
(ii) • • •
Contaminant
FkKxxJo ...,,..-.-— ....
Mercury ~~ ....
Mrtfil*..
Acceptance limit
2 standard deviations
based on study
statistics
±15% at £0.15 mg/l
±20% at £ 0.002 mg/l
±15% at £0.01 mg/l
±10% all to 'Tmg/l
±30% at aO.OKS mg/l
±10% at &o * .--.jj/l
±15% at £C * rr.g/1
±20% at £0:01 mg/l
(I) Analyses for the purpose of
determining compliance with § 141.11
shall be conducted using the
requirements specified in paragraphs (1)
through (a) of this section.
(1) Analyses for all community water
aystems utilizing surface water sources
shall be completed by June 24,1078.
These analyses shall be repealed at .
yearly intervals.
(2) Analyses for all community water
systems utilizing only ground water
sources shall be completed by June 24,
1979. These analyses shall be repeated
at three-year intervals.
(3) For non-community water systems,
whether supplied by surface or ground
sources, analyses for nitrate shall be
c completed by December 24,1980. These
analyses shall be repeated at intervals
determined by the State.
(4) The State has the authority to
determine compliance or Initiate
enforcement action based upon
analytical results and other information
compiled by their sanctioned
representatives and agencies.
(m) If the result of an analysis made
under paragraph (1} of this section
indicates that the level of any
contaminant listed in 5141.11 exceeds
the maximum contaminant level, the
supplier of the water shall report to the
Slate within 7 days and initiate three
additional analyses at the same
sampling point within one month.
(n) When the average of four analyses
made pursuant to paragraph (m) of this
section, rounded to the same number of
significant figures as the maximum
contaminant level for the substance in
question, exceeds the maximum
contaminant level, the supplier of water
shall notify the State pursuant to
§ 141.31 and give notice to the public
pursuant to § 141.32. Monitoring after
public notification shall be at a
frequency designated by the State and
shall continue until the maximum
contaminant level has not been
exceeded in two successive samples or
until a monitoring schedule as a !
condition to a variance, exemption or
enforcement action shall become
effective.
(o) The provisions of paragraphs (m)
and (n) of this section notwithstanding,
compliance with the maximum
contaminant level for nitrate shall be
determined on the basis of the mean of
two analyses. When a level exceeding
the maximum contaminant level for
nitrate is found, a second analysis shall
be initiated within 24 hours, and if the
mean of the two analyses exceeds the
maximum contaminant level, the
supplier of water shall report his
findings to the State pursuant to § 141.31
and shall notify the public pursuant to
S 141.32.
(p) For the initial analyses required by
paragraph (1) (1), (2) or (3) of this
section, data for surface waters
acquired within one year prior to the
effective date and data for ground
waters acquired within 3 years prior to
the effective date of this part may be
substituted at the discretion of the State.
(q} Analyses conducted to determine
compliance with § 141.11 shall be made
in accordance with the following
methods, or their equivalent as
determined by the Administrator.
(1) Arsenic-Method l 206i Atomic
Absorption Furnace Technique; or
Method > 206.3. or Method * D2972-88B
or Method * 307A, or Method 31-1062-
85, Atomic Absorption—Gaseous
Hydride; or Method » 208.4, or Method "•
D-2972-88A, or Method * 307B,
Spectrophotometric, Silver
Diethyldithiocarbamate: or Method 8
200.7, Inductively Coupled Plasma
Technique.
(2) Barium-Method ' 208.1 or Method 2
308, Atomic Absorption—Direct
Aspiration; or Method > 208.2, Atomic
Absorption Furnace Technique; or
Method • 200.7, Inductively Coupled ,
Plasma Technique.
(3) Cadmium-Method l 213.1 or
Method'* D 3557-78A or B, or Method 2
310A, Atomic Absorption—Direct
Aspiration; or Method l 213.2 Atomic
Absorption Furnace Technique; or
Method • 200.7, Inductively Coupledd
Plasma Technique. -
(4) Chromium-Method l 218.1 or
Method * D1687-77D, or Method 2 312A,
Atomic Absorption—Direct Aspiration;
or Chromium-Method : 218.2 Atomic
Absorption Furnace Technique; or
Method • 200.7, Inductively Couple
Plasma Technique.
(5) Mercury-Method ' 245.1, or
Method * D-3223-69, or Method * 320A,
Manual Cold Vapor Technique; or '
Method » 245.2, Automated Cold Vapor
Technique.
(6) Nitrate-Method » 352.1, or
Method4 D-992-71. or Methodl 353.3,
or Method * D-3867-79B, or Method *
418-C, Spectrometric, Cadmium
Reduction; Method » 353.1, Automated
Hydrazine Reduction; or Method '353.2,
or Method * D-3867-79A, or Method a
418F, Automated Cadmium Reduction.
»"Method* of Chemical Analysis of Water and
Wastes." EPA Environmental Monitoring and
Support Laboratory. Cincinnati. Ohio 45268 (EPA-
600/4-79-020). March 1963. Available from ORD
Publication*. CER1. EPA. Cincinnati. Ohio 45288. For
approved analytical procedural for metals, the
technique applicable to total metals must be used.
s "Standard Methods for the Examination of
Water and Wasiewater." 18th Edition. American
Public Health Association. American Water Work*
Association, Water Pollution Control Federation.
19S5.
• Technique* of Water-Resources Investigation of
the United States Geological Survey, Chapter A-l. -
"Method* for Determination of Inorganic
Substance* in Water and Fluvial Sediments." Book ,
5. 1879. Stock #024-001-03177-8. Available from
Superintendent of Documents. U.S. Government
Printing Office, Washington. DC 20402.
* Annual Book of ASTM Standards, part 31
Water. American Society for testing arid Materials.
1078 Race Street. Philadelphia. Pennsylvania 19103.
• "Inductively Coupled Plasma-Atomic Emission
Spectrometric Method for Trace Element Analysis . "
of Water and Watte*— Method 200.7" with
Appendix to Method 200.7 entitled, "Inductively^
Coupled Plasma-Atomic Emission Analysis of
Drinking Water." March 1967. Available from EPA's
Environmental Monitoring and Support Laboratory.
Cincinnati. Ohio 45268.
-------
Register./, Vpl, 56,- No.' l£6i/'Monday,' July I>'a99t /.Rules•.j»ndof the initial determination, then
the waiver is invalidated and the system
is required to sample annually as
specified in paragraph (5) of this section.
(10]: Each community and non-
transient isurface water system which •
does mot detect a contaminant listed in
S 14I.|61(a) (1) through (18) may apply to
the Stiate for a waiver from the
requirements of (f}(5)I of this section
after completing the initial monitoring.
Systems meeting this criteria must be
determined by the State to be non-
vulne!rable based on a vulnerability
assessment during each compliance
period. Each system receiving a waiver
shall Isample at the frequency specified
by thb State (if any).
(11) If a contaminant listed in
§ 141.61(£i) (2) through (18) is detected at
a level exceeding 0.0005 mg/1 in any
samrjle. then:
-------
Federal Register / Vol. 5.6.. No. 126 / Monday^ July 1^.1931 / Rules and .Regulations
(1) The system mnst monitor quarterly
at each campling point which resulted in
a detection.
(if) The State may decrease the
quarterly monitoring requirement
specified in paragraph (f)(HJW of &**
section provided it has determined thai
the system is reliably and consistently
below the maximum contaminant level.
In no case shall the State make this
determination tmless a gronndwater
system takes • minimum of two
quarterly samples and a surface water
system takes a minimum of four
quarterly samples.
(iii) If the State determines that the
system is reliably and consistently
below the MCL. the State may allow the
system to monitor annually. Systems
which monitor annually must monitor
during the quarterfs) which previously
yielded the highest analytical result
(iv) Systems which have three
consecutive annual camples with no
detection of a contaminant may apply to
the State for a waiver as specified in
paragraph (fWT) of this section.
(v) Groundwater systems which have
detected one or more of the following
two-carbofi organic compounds:
trichloroemylene. tetrachloroethylene,
1.2-dichloroethane, 1,1,1-trichloroethane,
cis-l,2-dichloroethylene, trans-1.2-
dichloroethylene, or 1,1-
dichloroethylene shall monitor quarterly
for vinyl chloride. A vinyl chloride
sample shall be taken at each sampling
point at which one or more of the two-
carbon organic compounds was
detected. If the results of the first
analysis do not detect vinyl chloride, the
State may reduce the quarterly
monitoring frequency of vinyl chloride
monitoring to one sample during each
. compliance period. Surface water
systems are required to monitor for
vinyl chloride as specified by the State.
(12) Systems which violate the
requirements of § 141.61(a) (1) through
(18), as determined by paragraph (f](15)
of this section, must monitor quarterly.
After a minimum of four consecutive
quarterly samples which show the
system is in compliance as specified in
paragraph (f)(15) of this section the
system and the State determines that
the system is reliably and consistently
below the maximum contaminant level
the system may monitor at the
frequency and time specified in
paragraph (f){ll}{ii>] of this section.
(13) The State may require a
confirmation sample for positive or
negative results. If a confirmation
sample is required by the State, the
result must be averaged with the first
sampling result and the average is used
for the compliance determination as
specified by paragraph (f)(15)-States
have discretion to delete results of
obvious sampling errors from this
calculation.
(14) The State may reduce the total
number of samples a system mnst
analyze by allowing the ose of
compositing. Composite samples from a
maximum of five sampling points are
allowed. Compositing of samples must
be done in the laboratory and analyzed
within 14 days of sample collection.
(i) If the concentration in the
composite sample is ^ 0.0005 mg/I for
any contaminant listed in i 141.61(a),
then a follow-up sample must be taken
and analyzed within 14 days from each
sampling point included in the
composite.
(ii) If duplicates of the original sample
taken from each sampling point used in
the composite are available, die system
may use these instead of resampling. ,
The duplicate must be analyzed and the
results reported to die State within 14
days of collection.
(iii) Compositing may only be
permitted by die State at sampling
points within a single system, unless die
population served by die system is
^ 3,300 persons. In systems serving
^ 3,300 persons, die State may permit
compositing among different systems
provided die 5-sample limit is
maintained.
(iv) Compositing samples prior to GC
analysis. -
(A) Add 5 ml or equal larger amounts
of each sample (up to 5 samples are
allowed) to a 25 ml glass syringe.
Special precautions must be made to
maintain zero headspace in die syringe.
(6) The samples must be cooled at 4*C
during mis step to minimize
volatilization losses.
(C) Mix well and draw out a 5-ml
aliquot for analysis.
(D) Follow sample introduction,
purging, and desorption steps described
in the method.
(E) If less than five samples are used
for compositing, a proportionately small
syringe may be used.
(v) Compositing samples prior to GC/
MS analysis.
(A) Inject 5-ml or equal larger
amounts of each aqueous sample (up to
5 samples are allowed) into a 2S-ml
purging device using the sample
introduction technique described in die
method.
(B) The .total volume of die sample in
die purging c-ww* must be 25 mi.
(C) Purge i*'.'ri 4«iorb a»described in
die method
(15) Compliance with § 141.61{a} (1}
through (18) shall be determined based
on die analytical results obtained at
each sampling point.
(i) For systems which are coixhictirig
monitoring at a frequency greater than
annual, compliance is determined by a
running annual average of all samples
taken at each sampling point. If die
annual average of any sampling pomt is
greater dian die MCL. daen d*e system is
out of compliance. If the initial sample
or a subsequent sample would canse the
annual average to be exceeded, die» the
system is out of compliance
immediately.
(ii) If monitoring is conducted
annually, or less frequently, die eyslem
is out of compliance if die level of a
contaminant at any sampling point ia
greater dian dse MCL. If a confirmation
sample is required by die State, die
determination of compliance will be .
based on the average of two samples.
(iii} If a public water system has a
distribution system separable from odier
parts of die distribution system With no
interconnections, die State msy allow
die system to give public notice to only
that area served by that portion of die
system which is out of compliance.
" (18) Analysis for die contaminants
listed in 5 141.61(a) (1) through (18) stall
be conducted using die following EPA
methods or their equivalent as approved
by EPA. These methods are contained in
Methods for die Determination of
Organic Compounds m Drinking Water,.
ORD Publications, CERI, EPA/600/4-88/^
039, December 1988. These documents
are available from die National
Technical Information Service (NTIS),
U.S. Department of Commerce, 5285 Port
Royal Road. Springfield, Virginia 22161.
The toll-free number is 8CO-336-4700.
(i) Method 502.1, Volatile
Halogenated Organic Chemicals in
Water by Purge and Trap Gas
Chromatography."
(ii) Mediod 502.2, "Volatile Organic
Compounds in Water by Purge and Trap
Capillary Column Gas Chromatography
with Photoionization and Electrolytic
Conductivity Detectors in Series."
(iii) Method 503.1, "Volatile Aromatic
and Unsaturated Organic Compounds in
Water by Purge and Trap Gas
Chromatography."
(iv) Method 524.1. "Measurement of
Purgeable Organic Compounds in Water
by Purged Column Gas
Chromatography /Mass Spectrometry."
(v) Mediod 524.2, "Measurement of
Purgeable Organic Compounds in Water
by Capillary Column Gas
Chromatography /Mass Spectrometry.*'
(17) Analysis under diis section shall
only be conducted by laboratories thatt
are certified by EPA or die State
according to die following conditions:
(i) To receive certification to conduct
analyses for the contaminants in
-------
Tedera! Register'/ Vol. 56,' No. 128 /Monday, July l'.;'lSr9'l '/' Rules!; ana ReguliUoks . : S0279
§ 141.61fa)(2) throiigh (18) the
laboratory must:
(A) Analyze Performance Evaluation
samples which include these substances
provided by EPA Environmental
Monitoring and Support Laboratory or
equivalent samples provided by the .
State.
(B) Achieve the quantitative ' .
acceptance limits under paragraphs
(0(17{i) (C) and (D) of this section for at
least 80 percent of the regulated organic
chemicals listed in § 141.61(a) (2)
through (18).
(C) Achieve quantitative results on
the analyses performed under paragraph
{f)(17)(i)( A) ofJhis section that are
within ±20 percent of the actual amount
«jf the substances in the Performance
Evaluation sample when the actual
amount is greater than or equal to 0.010
mg/1. .
(D) Achieve quantitative results on
the analyses, performed under paragraph
(f)(17)(i)(A} of this section that are
within ±40 percent of the actual amount
of the substances in the Performance
Evaluation sample when the actual
amount is less than 0.010 mg/1.
(E) Achieve a method detection limit
of 0.0005 mg/1, according to the
procedures in appendix B of part 136.
(ii) To receive certification for vinyl
chloride, the laboratory must:
(A) Analyze Performance Evaluation
samples provided by EPA
Environmental Monitoring and Support
Laboratory or equivalent samples
provided by the State.
{B} Achieve quantitative results on the
analyses performed under paragraph
(f)(17)(ii)(A) of this section that are
within ±40 percent of the actual amount
of vinyl chloride,in the Performance
, Evaluation sample.
(C) Achieve a method detection limit
of 0.0005 mg/1, according to the
procedures in appendix B of part 136.
(D) Obtain certification for the
contaminants listed in § 141.61 (a) (2)
through (18). ,'-•'•
(18) States mey allow the use of
monitoring data collected after January
1,1988, required under section 1445 of
the Act for purposes of initial monitoring
compliance. If the data are generally
consistent with the other requirements
in this section, the State may use these
data (i.e., a single sample rather than
four quarterly samples) to satisfy the
initial monitoring requirement of
paragraph (f)(4) of this section. Systems
which use grandfathered samples and
did not detect any contaminant listed in
§ 141.61(a) (1) through (18) shall begin
monitoring annually in accordance with
paragraph (f){5) of this section beginning
January 1.1993. "
(19) States may, increase required
monitoring where necessary to detect
variations within the system.
(20) Each approved laboratory must
determine the method detection limit
(MDL), as defined in appendix B to part
136, at which it is capable of detecting
VOCs. The acceptable MDL is 0.0005
mg/1. This concentration is the detection
concentration for purposes of this ,
section.
(21) Each public water system shall
monitor at the time designated by the
State within each compliance period.
(g) For systems in operation before
January 1,1993, for purposes of initial
monitoring/analysis of the contaminants
listed in § 141.61(a) (1) through (8) for
purposes of determining compliance
with the maximum contaminant levels
shall be conducted as follows:
* •' * * *. • •
(8) Until January 1.1993, the State
may reduce the monitoring frequency in
paragraphs (g)(l) and (g)(2) of this
section, as explained in this paragraph.
« *'*'*'« • • •
(h) * * *
(8) Systems which violate the
requirements of 1141.61(c) as
determined by paragraph (h){ll) of this
section must monitor quarterly. After a
minimum of four quarterly samples
show the system is in compliance and
the State determines the system is
reliably and consistently below the
MCL, as specified in paragraph (h)(ll) of
this section, the system shall monitor at
the frequency specified in paragraph
(h)(7)(iii) of this section.
**;***
• ' (12)
(iv) Method 508, "Determination of
Chlorinated Pesticides in Water by Gas
Chromatography with an Electron
Capture Detector." Method 508 can be
used to measure chlordane, heptachlor,
heptachlor epoxide. lindane,
methpxychlor and toxaphene. Method
508 can be used as & screen for PCBs.
* '*••*.•
(vi) Method 515.1, Revision 5.0,
"Determination of Chlorinated Acids in
Water by Gas Chromatography with an
Electron Capture Detector'* as revised
May 1991. Method 515.1 can be used to
measure 2,4-D, 2.4.5-TP (Silvex) and
pentachlorophenol.
(vii) Method 525.1. Revision 3.0
"Determination of Organic Compounds
in Drinking Water .by Liquid-Solid
Extraction and Capillary Column Gas
Chromatography/Mass Spectrometry"
as revised May 1991. Method 525.1 can
be used to measure alachlor, atrazine,
chlordane. heptachlor, heptachlor
epoxide. lindane, methoxychlor. and
pentachlorophenol.
(13) * * * .
(i) Eiach system which monitors for
PCBs shall analyze each sample using
eitheri Method 505 or Method 508 (see
paragraph (h){12) of this section).
* >» * • * * -
(19); Anaylsis under this section shall
only lie conducted by laboratories that
have received certification by EPA or
the State and have met the following
conditions:
• (i) To receive certification to conduct
analyses for the contaminants in
1141.61(cl the laboratory must:
(A)'Analyze Performance Evaluation
samples which.include those substances
provided by EPA Environmental - >
Monilioring and Support Laboratory of
equivalent samples provided by the
State,'
(B) Achieve quantitative results on the
analyses that are within the following
acceptance limits:
(Contaminant
: !
i
DSCP ' ' _ ...
EDS -i. _
Alacnlcir -.—
Atrazine .._
Cafbof 'jran ..„ _..«..«.......
Qilo
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30280
Federal Register / Vol. 58. No. 126 / Monday, July 1. 1991 / Rules and Regulations
(o high levels during (heir lifetimes. In
humans, EPA believes that effects from
barium on blood pressure should not
occur below 2 parts per million (ppm) in
drinking water. EPA has set the drinking
water standard for barium at 2 parts per
million (ppm] to protect against the risk
of these adverse health effects. Drinking
water that meets the EPA standard is
associated with little to none of this risk
and is considered safe with respect to
barium.
• • • • »
(25) Aldicarb. The United States
Environmental Protection Agency (EPA)
sett drinking water standards and has
determined that aldicarb is a health
concern at certain levels of exposure.
Aldicarb U a widely used pesticide.
Under certain soil and climatic
condition* (e^, candy soil and high
rainfall), aldicarb may leach into ground
water after normal agricultural
applications to crops such as potatoes or
peanuts or may enter drinking water
supplies as a result of surface runoff.
This chemical has been shown to
damage the nervous system in
laboratory animals such as rats and
dogs exposed to high levels. EPA has set
the drinking water standard for aldicarb
at 0.003 parts per million (ppm] to
protect against the risk of adverse
health effects. Drinking water that meets
the EPA standard is associated with
little (o none of this risk and is
considered safe with respect to aldicarb.
(26) Aldicarb auffaxide. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that aldicarb sulfoxide
is a health concern at certain levels of
exposure. Aldicarb is a widely used
pesticide. Aldicarb sulfoxide in ground
water !s primarily a breakdown product
cf aldicarb. Under certain soil and
climatic conditions (e.g., sandy soil and
high rainfall), aldicarb sulfoxide may
leach into ground water after normal
agricultural applications to crops sach
as potatoes or peanuts or may enter
drinking water supplies as a result of
surface runoff. This chemical has been
shown to damage the nervous system in
laboratory animals such as rats and
dogs exposed to high levels. EPA has set
the drinking water standard for aldicarb
sulfoxide at 0.004 pans per million (ppm)
to protect against the risk of adverse
health effects. Drinking water that meets
the EPA standard is associated with
little to none of this risk and is
considered safe with respect to aldicarb
sulfoxide.
(27) Aldicarb sulforc. The United
Slates Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that aldicarb sulfone is
a health concern at certain levelaof
exposure. Aldicarb is a widely used
pesticide. Aldicarb sulfone is formed
from the breakdown of ekiicarb and is
considered for registration as a pesticide
under the name aldoxycarb. Under
certain soil and climatic conditions {e.g.,
sandy soil and high rainfall), aldicarfa
sulfone may leach into ground water •
after normal agricultural applications to
crops.such as potatoes or peanuts or
may enter drinking water supplies as a
result of surface runoff. This chemical
has been shown to damage the nervous
system in laboratory animals such as
rats and dogs exposed to high levels.
EPA has set the drinking water standard
for aldicarb sulfone at 0.002 parts per
million (ppm) to protect against the risk
of adverse health effects. Drinking water
that meets the EPA standard is
associated with little to none of this risk
and is considered safe with respect to
aldicarb sulfone,
* * * * *
(46) Pentachhrophenol. The United
States Environmental Protection Agency
(EPA) sets drinking water standards and
has determined that pentachtarophenol
is a health concern at certain levels of
exposure. This organic chemical is wed
as a wood preservative, herbicide,'
disinfectant, and defoliant. It generally
gets into drinking water by ronoff into
surface water or leaching into ground
water. This chemical has been shown to
produce adverse reproductive effects
and to damage the liver and kfsr,eys of
laboratory animals such as rats exposed
to high levels during their lifetimes. ,
Some humans who were exposed to
relatively large amounts of this chemical
also suffered damage to the liver snd
kidneys. This chemical has been shown
to cause cancer in laboratory animals
such as rats and mice when the animals
are exposed to high levels over their
lifetimes. Chemicals that cause cancer in
laboratory animals also may increase
the risk of cancer in humans who are
exposed over long periods of time. EPA
has set the drinking water standard for
pentachlorophenol at 0.001 parts per
million (ppm) to protect against the risk
of cancer or other adverse health
effects. Drinking water that meets the
EPA standard is associated with little to
none of this risk and is considered safe
with respect to pentachlorophenol.
8. Section 141.50 is amended by
adding paragraphs (a)(15), (b)(4). (b)(5).
and (b)(6) to read as follows:
5 141.50 Maximum contaminant level
goals for organic chemicals.
(a) • * •
(15) Pentachlorophenol
(b) • • - •
Contaminant
(4) Aldicarb..
(5) Aldicartj sulfajode
(6) AWtearb sulfone
0-OOt
0.001
0.001
9. Section 141.51 is amended by
adding paragraph (b)(3) as follows:
§ 141.51 Mtxfmum contaminant tevet
goals for Inorganic contaminants.
* * * « ., o
(b) •' * •
' Contaminant
MCU3
.(3) Barium-
10- Section 141.61 is amended by
adding to the table paragraphs (c)(2),
(c)(3). (c)(4), and (c)(16) to read as
follows:
{ 141.61 Maximum contaminant levels for
organic contaminants.
CAS No.
Contaminant
MO.
(2) 116-06-3....
O) 1646-87-3-
(4) 1646-87-4-
•
(16) 87-e6-5.__
Aldicarb.
Aldicartj suKoride —
Akkcarta suHoneJ—
* «
Pantachlorophenol..
0.003
O.004
0.003
•
0X21'
11. In § 141.62, paragraph (bKl) is
revised and (b}(3) is added to read as
follows:
5141.62 Uaximuni contaminant levels tor
inorganic contaminants.
*, • ' • * * . '
(b)* • ''
Conurainant
(1) Huortto—
•
(3) Barium..
4.0
2
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Federal Register / Vol. 56. No. 126 / Monday. July. 1." 1991 / Rules and Regulations ,. 3C2S1
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
12. The authority citation for part 142
continues to read as follows:
Authority. 42 U.S.C. 300g. 300g-l. 300g-2,
300g-3. 300g-4. 300g-S, 300g-«. 300J-4 and
SOOj-9.
13. In 5 142.57. which was published
January 30,1991 (56 FR 3526) and will
become effective July 30,1992.
paragraph (b) is revised to read as
follows:
514257 Bottled Water, Polnt-of-Use.
•' • • •, « ••
(b) Public water systems using bottled
water as a condition of obtaining an
exemption from the requirements of
55141.61 (a) and (c) and { 141.62(b)
must meet the requirements in -
5l42.62(g).
PART 143—NATIONAL SECONDARY
DRINKING WATER REGULATIONS
14. The authority citation for part 143
continues to read as follows:
Autk*tty:42U.S.C.300g-l(c),300j-t«fld
300J-8.
15, In 5 143.4, which was published
January 30,1991 (56 FR 3526) and which
will become effective Jury 30,1992,
paragraphs (b) (12) and (13) are revised
to read as follows:
§ 143.4 Monitoring. ,
.
(12) Aluminum--Method » 202.1
Atomic Absorption Technique-Direct
Aspiration; or Method * 306A; or
Method * I-305i-^5, or Method » 202.2
Atomic Absorption-Graphite Furnace
Technique; or Method * 304; or Method *
* "Methods of Chemical Analysii of Water and
Waste*." EPA. Environmental Monitoring and
System* Laboratory, Cincinnati OH 45268. EPA
600/4-79-020. March, 1983. Available from ORD
Publication. CERL EPA, Cincinnati. OH 45266.
« "Standard Method* for the Examination of
Water and Wastewater," 16th Ed. American Public
•Health As*ocUtioa.> American Waterwork*
Association. Water Pollution Control Federation.
1985.
» "Method* for the Determination of Inorganic
Subitancet in "Water and Fluvial Sediments,"
Technique* of Water-Re*ource* Investigation* of
(he United State* Geological Survey Book*. Chapter
Al. 19S5. Available from Open File Services
Section. Western Distribution Branch. U.S.
Geological Survey, Denver "Federal Center, Denver,
CO 80255.
* "Determination of Metals and Trace Elements
by Inductively Coupled Plasma-Atonic Emission
Specsrometry," Method 20CL7, version ii August.
1990, EPA Environmental Monitoring and Systems
Laboratory. Cincinnati. OH 45286.
2O0.7 Inductively-Coupled Plasma
Technique: or Method s 200.8
Inductively Coupled Plasma-Mass
Spectrometry or Method e 200.9 Platform
Technique; or Method 7 3120B
Inductively-Coupled Plasma Technique.
(13] Silver—Method ! 272.1 Atomic
Absorption Technique-Direct
Aspiration; or Method 2 324A; or
Method 3 1-3720-85; or Method ' 272.2
Atomic Absorption-Graphite Furnace
Technique; or Method * 304; or Method *
,200.7 jlnductively-Coupled Plasma- .
Technique; or Method 5 200.8
Inducti%-e!y-Coupled Plasma-Mass
Speclrometry; or Method 6 200.9
Piatf<)rm Technique; or Method 7 3120B
Inducitively-Coupled Plasma-Technique.
[FR D>bc. 91-15564
BIUJM<> COOC f 580-50-M
• "Determination of and Trace Element* in Wa*cr
and Wastes by Inductively Coupled Ptosma-Wma
Spectrometry." Method 200J5. version 4A August.
1990. E1PA. Environmental Monitoring and Systems
Uboratory, Cincinnati, OH 45268. Available from
ORD Publication. CERI. EPA. Cincinnati. OH 45268.
• "Determination of Metals and Trace Elements
bj- Stabilized Temperature Graphite Furnace
Atomic Absorption Spectrometry," Method 200A j
version 1.1. August 1990, EPA. Environmental
Monitoring and System* Laboratory, Cindnrurti. OH
45208.1 '"•- *
'"Standard Method* for the Examination of
Water and Wa»tewater." 16th ed, America*.Public
Health A»sociation. American Waterworit*
Association. Water Pollution Control Federation,
1905.
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