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3B2sa” Federal Register / Vol. 56, No. 126 / Monday, July 1, 1991 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 141,142 and 143 

RIM 2040-AA55 

IFRL-3960-1 I 

Drinking Water; National Primary

Drinking Water Regulations; 

Monitoring for Volatile Organic

Chemicals; MCLGs and MCLs for 

Aldicarb, Aldicarb Sulfoxide, Aldicarb 

Sulfone, Pentachlorophenol, and 

Barium 

AGENCY: EnvironmentalProtection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY:In this notice, EPA is revising

monitoring requirements for eight

volatile organic contaminants (VOCs)

originally promulgatedJuly 8,1987. This 

change synchronizesrequirements for 

these eight VOCs with monitoring

raquirements 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

promulgatedJanuary 30,1991 (56 EX 

3526). 

EFFECTIVE DATE: The amendments to 

Q 141.6, paragraph (c) of the table in 

fi 141.12. and Q 141.62(b)(l)are effective 

July 1,1991. The amendments to 

fi 0 141.11(b),141.23,141.24,142.57, 

143.4(b)(12)and (b)(13),are effective 

July 30,1992. The revisions to 

Q 141.32[e)f16),(25) through (27) and (46);

fi 141.50(a1(15),(b)(4),(bI(5)and (bl(6); fi 141.51(b)!3); Q 141.61(~)(2), (c)3, (c)(4)

and (cI(26); 8 141.62(b)(3)are effective 

January 1,1993. 

The barium information collection 

requirements of 0 141.23 are effective 

January 1,1993, if the information 

CollectionRequest 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 1p.m., Eastern time on 

July 15,1991. 

ADDRESSES: A copy of the public 

comments received, EPA responses, and 

all other supportingdocuments 

(including references included in this 

notice) are available for review at the 

U.S.Envirenmental ProtectionAgency

(EPA), Drinking Water Docket, 401 M 

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 8RO-336-470, local: 703-487­

4650. 

FOR FURTHER INFORMATION, CONTACT: 

A1 Havinga, Standards Division, Office 

of Ground Water and Drinking Water 

(WH-550), US.Environmental 

Protection Agency, 401 M Street, SW., 

Washington, DC 20460,202/382-5555.

General informationmay also be 

obtained from the EPA Drinking Water 

Hotline. The toll-free number is 800/426­

4791, Alaska and local: 202/382-5533. 

SUPPLEMENTARY1WFORMATION: 

Table of Contents 

I. Statutory Authority

11. Regulatory Background 

111. Explanation of Today’s Action 

A. VOC MonitoringRequirements 

1.StandardizedMonitoringFramework 

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. PentachlorophenolMCL 

D. Barium 

1. Barium MCLG 

2. Barium MCL 

E.1415 Variance Option

F. Analytical Methods 

G. Corrections to the January30,1991 

Notice 

IV. Economic Analysis

A. RegulatoryImpact

B. Regulatory Flexibility Analysis

C. Paper Work Reduction Act 

1. Statutory Authority 

The Safe Drinking Water Act 

(“SDWA’or “the Act”), as amended in 

1986 (Pub. L. 99439,100 Stat. @2), 

Rules and Regulatidns 

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 

1412(b)(4)).

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 maxim- contaminant level 

(MCL),or (2) a required treatment 

technique (section 1401(1),1412[a)(3),

and 1412(b)(7)(A)).A treatment 

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 

close 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 1401(1)(D]).Section 1445of 

SDWA also authorizes EPA to 

promulgatemonitoring requirements. 

11. Regulatory Background 

On July 8,1987EPA 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 

chemicalswere reproposed on January

30,1991 (56 FR. 3600) at different levels 

due to informationwhich was received 

and/or analyzed by the Agency

subsequent to the May 22,1969 

proposal. 

The monitoring requirements outlined 

in today’s rule for the most part mirror 

(with several exceptions, as noted 

below) the VOC requirements published 

3 
3 
1987 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 

(Le., less than one percent of the time]

with a detection limit of 0.0005 mg/l.

However, we note that requirements in 

8 141.24 (fl(13) also allow the State to 

require confirmation samples for 

positive or negative results. In addition, 

the State has 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 

limits. 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 

commenter 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 

MCE 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 be 

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 sus9ptibility.

Several commenters noted aat 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 assessqents from States to 

water systems because we believe that 

these assessments arepart 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 mode available to 

water systems and States prior to the 

compliance period which begins January 

1,1993.

Ourgoals are to efficientlyutilize 

State and PWS resources and to be 

consistent with Phase I1 monitoring

requirements. EPA believes that today’s

rule furthers these goals. 

B. Aldicarb, Aldicarb Sulfoxide and 

Aldicarb Sulfone 

1.Aldiicarb, Aldicarb Sulfoxide and 

Aldicarb Sulfone MCLGs 

On January 30,1991 EPA reproposed

MCLGs for aldicarb, aldicarb sulfoxide, 

and aldicarb sulfone at O.o01,G.o01, and 

0.002 mg/kg/day. The MCLG for each of 

the three chemicals was based an 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 carcinogenicity). 

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 commenters responded to the 

January 1991 proposal. One commenter 

argued that EPA’s Rfe) of 0.0002 mg/kg/

day used in developing the proposed

aldicarb MCLG is legally and 

scientifically unsupportable. 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 

cormnenter suggested wing the NOAEL 

for clinical signs in this study, 0.05 mg/

kg, and a 10-foold uncertainty factor 

to establish the MCLG. For aldicarb 

sulfone, this commenter indic<atedthat 

the lowest dose tested in the one-year

dog feeding study (Hazleton Labs, 1987). 

0.11mg/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 sulfone, 

based on the revised RfD of O.OOO2 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 commgnter also noted that 

establishing an MCLG based on ChEI is 

inconsistent with the Agency regulation

for fluoride and silver. 

Response to PuSlic Comments 

Aldicarb and aldicarb sulfoxide.The 

Agency reproposed an MCLG of 0.001 

mg/l for ddicarb and aldicarb sulfoxide 

based on a revised RD 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 cholinesterase inhibition (ChEI) in 

animals and humans following exposure 

to 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 sulfoxidereported 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 function, histological

damage or other clinical effects in 

exposed individuals. Thefe are 

instances, though, where low levels of 

ChJ3 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 sulfoxide 

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. 

Y 
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 currentiy evaluating the 

correlation between ChEI and clinical 

signs of toxicity. Ifthe conclusions of 

this evaluation alter the basis presented

for t!ne 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. EPip

will continue to examine the relevance 

of using C&I in establishing an MCLG. 

Over a period of time this effort is 

expected to resolve the questions

related to the significance of ChEjl.

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 RfLl 

and the alternative derivation of the 

'MCLG result in an MCLG value of 0.001 

mg/l, the Agency is promulgating the 

MCLG at this level. An MCLG of 0.001 

mgll will be sufficiently protective of 

public health. 

"he final MCLG of 0.001mg/l 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. lac., 1988).At 

higher doses, effects such as diarrhea 

and soft stools were observed. The 

Agency has determined that these signs 

are representative of clinical signs of 

toxicity, In keeping with general Agency

practice (56FR 35321, an uncertainty

factor of 100was 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 rnglkglday, is 

numerically the same as the Rfb) 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/l.

The no-effect level of 0.02 mglkglday

and resulting MCLG of 0.001 mg/l is 

supported qualitatively by a controlled 

human study (Haines, 19711and takes 

into consideration the observation 

reported in the Goldman study (1990). In 

the Haines study, no significant clinical 

effectswere observed in four healthy

males given doses of 0.025 or 0.05 mgl

kglday. A higher dose of 0.1 mglkglday

resulted ilt neurological effects. The noeffect level of 0.05 mgfkglday 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 studied, 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 reporkd by

Haines. 

Goldman el al. reported clinical 

ef'fects in humans (including women and 

children) following three separate

incidents involving aldicarblaldicarb 

sul�oxidein California. Exposure to 

aldicarb sulfoxide from the 

contaminated watermelons and 

cucumbers were estimated to range from 

0.002 to 0.08 mglkg body weight. A OW 

effect level for clinical effects was 

estimated at 0.082 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 selfreports 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 &e dog and 

human studies taken together support

the calculation of an MCEG of 0.001 

ng/ 1. 

In summary, the Agency is 

promulgating an MCLG of 0.001mgll for 

aldicarb and aldicarb sulfoxide based 

on a weight of evidence of clinical signs

of toxicity observed in humans and 

animals. 

Aldicurb sulfone. 

The Agency reproposed an MCLG of 

0,002 mg/L for aldicarb sulfone in the 

January 30,1991notice. This level was 

based on a no-observed-adverse-effect 

level for ChEI in blood of 0.1mg/kg/day

snd 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 LD~ofor 

the sulfone is 25 mglkglday compared 

to the LDSOfor aldicarb of 1mg/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 

0.001mg/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, than the Agency will initiate a 

process for determining whether the 

MCLG for aldicarb sulfone should be 

revised. 

In summary, the Agency is 

promulgating an MCLG of 0.001mgll for 

aldicarb sulfone. 

2. Aldicarb, Afdicarb Sulfoxide, and 

Aldicarb Sulfone MCLs 

The proposed MCLs for aldicarb, 

aldicarb sulfoxide, and aldicarb sulfone were based upon an analysis of several 

factors including: (I]The effectiveness 

of the best available technology [BATgranular activated carbon) in removing

aldicarb, ddicarb sulfoxide, and 

aldicarb sulfone to levels at or below 

the proposed MCLs of 0.003 mg/k (2) the 

feasibility [including costs) of applying

BAT for large systems. EPA estimated 

that he cost io remove aldicarb, 

al2icarb sulfoxide and aldicarb sulfone 

using GAC to be $10-14 per household 

and thus feasible; and (31 the 

performance of analytical methods as 

reflected iri the practical quantification

level (PQL] fer each contaminant. In the 

proposed notice EPA stated that data 

from Water Saipply Studies showed that 

the PQLs for aldicarb, aPdicarPJ 

sulfoxide. and aldicarb sul�onecould be 

set at 0.803 ng/l by broadening the 

acceptance limits to A%%. 

The pivotal comments concerned 

establishing the PQL for aldicarb, 

aldicarb sulfexide, and aldicarb sulfone. 

One conmenier noted that Water 

Suppay Studies *22-25 which were used 

to calculate the PQL did not "bracket" 

the proposed levels. This comrnenter 

noted that the lowest levels in Water 

Supply Studies *22-25 were 0.00947 mg/

B for aldicarb, 0.00867 mg/l for aldicarb 

sulfoxide, and 0.00833mg/i for aldicarb 

sulfone. Several commenters objected to

mil's adjustment of PQL acceptance

limits to achieve lower MCLs. These 

commenters noted that the usual Agency

practice is to use % 20% or ri: 40% of the 

true value. These comrnenters objected 

to the Agency's broadenh3 the 

acceptance limits to +. 55% arguing

instead that EPA should use a single

Fixed acceptance limit. 

After considering the comments, EPA 

Jecided to revisit the rationale on which 

the PQLs were based. As a result, the 

Agency concluded that the elements of 

the rationale that involved extrapolating

data were inappropriate for this 

compound.

EPA sei the proposed PQLs of 0.003 

,ng/l by extrapolating from the lowest 
IeveIs in Watm&pplg Wes#22-%, 

to tbe point &t Wh�B2% pemenl!dthe 

p&cipakhg foborakwieswdd be able 

to analyze wi&n; +55 persen8 of ths 

true vakbe. EPA USaQ tYs atmplation 

twm k.�wamse �hewater%p& 

St& #&a5 &W�y desigmdid not 

inelude the hvek ofconcern i.e, 

MCLGs of O.m%ad OW qjl preposed

in the bnwwy Nuhe f%FR 36~).

The existing Wster Supprsf SWies 

were designedto provide data for 

assessment of laboratory pfomance 

at levels of CORG- whick were higher

(Le., MCLGs oEO M mgli pmpsed in 

NoverabeP I%& @Q FR 4fi986)and &ol 

and Q.W rngb ppsed hMay 1989(54 

FR ZZW]), En thisease, the levels 

F valuated in theWater Supply Studies 

1Jere above &e tox.ied@ml levels of 

('omern &MKE E&) br aldiiarb, 

a !dicarb s&oxide mdddiearb rmlfoRe 

3spropcrsed in janmrjt 399%.For this 

reason we dedded k~ use an alternate 

procedure for setting &e PQL for 

:.Idicarb, which sets the PQL at five 

times the intedabmtory methad 

detection limit om,was first 

discussed in setting the MCL for vinyl

ChlQikhf52 25690, J&1987). W S 

proeedure is used ta setthe PQL when 

there is not water supply study data at 

the level of concern OH when the usual 

praceedure would res& in a PQLwhich 

poses a greater tharr 1&4 cancer risk. 

The ahficarb, aldkarb suhxide and 

aldicarb m&ne PQLs were determined 

using the range of 5 to 10times the 

IMDL. The PQb of O.W,0.004 and 0.002 

mg/l for aldicarb, aldicarbsulfwide and 

aldicarb sulfone, respectively, ape based 

on the lewer factor af 5 times&e 

respeztive IM3X.s ti.e.,0.W. 0- and 

0.OOO3 q&.EPA has previously stated 

(Le., EDB (56 FR 352611that thause of 5 

times the WDi. instead of 1Qtimesthe 

MDL to set the PQL may. be appropriate

when ather emsiderations suggest the 

PQL should be lower [Le., where there is 

a lack of performance evaluationdata at 

the level of concern for a particular

contaminant]. In the mse sfat$icarb 

and its metabolites, the Age~~y has 

decided to base the PQL ~15 times the 

IMDL because (a)it isfeasibleand @I)it 

is closer to the MCLG &.Ranthe io 

multiplier,,

The validatb study fopMethod 5a.z 

[the approved methad for the ai&oarbs]

provides evidence that a PQLof 3.Q -11 

is achievable f0r aldimrbi The design1

for this study is cornpamble Pa thatof 

tke Water Sapply Studies &e.,wnknown 

concentcations, magent pde water, 

colraborativet. Tha lewd of 0.W mg/k 

(3.24 pg/1, was analyzed for aldioarb in 

the study and dted in gwd preoisisn

2nd acowacy with a mean lUtc0vex-y OE 

3.26 pgfl and a standad deviatim a� 

0.33 pgP. Results danaly8esfix 

aldicarb sulfoxide and Ctfdia~hdine 

aIm had good precision an& acewaw 

but thftlevels analyzed were at letrefsof 

6.40and 8.44 pg/L respectively. EPA 

believes that these method vafidation 

resultsgive additional support�0~he 

PQLs. 

EPA recognizes that, at the PQL levels 

chosen, s32ghdp less precisionan$ 

accuracy will occnr. Huwwe~,EPA 

believes that it is appropriate to aecept

less precision in order to &ah mwe 

stringent levels of con&& B-se of 

the lack of performance eva1b-n 

studies at the MCLG, the acceptance

limits for aldicarb, aldicarlr sdfmide 

and aldicarb sulf~newiu he based on 

two standard deviations usingWater 

Supply Study statistics. EFA wili 

reevaluate this when it acquires the 

appmpriate data at levels below or at 

the PQLs, frem ongoing Water Supply

Study data to assess "fixed tme.vaIue" 

acceptance limits. EPA afso believes 

&at the precision and accuracy at these 

levels will improve after more use of the 

relatively new methodoIogy.

EPA has examined the health Fisk9 of 

setting �he MCLs above the MCLGs of 

0.001mg/l. Childrenare Bemost 

sensitlve population for these 

compounds. Howeversa child likely

would not consume a whole liter at one 

time. More typically children consume 

water throughout the day and this would 

mjtigate against adverse ef- at the 

hfCLs and below. The adverse effects of 

aldicarb are thought to be reversible 

within 4 to 6hours at higher levels of 

exposure. Therefore, EPA believes that 

the MCLs of 0+003mg/l for aldicarb, 

0.004mg/l for aldicarb sulfoxide and 

0.002 mgJl for aldicarb sulfone are 

protective for chitdren. Until t�ie 

analytical chemistry and laboratory

performance innprove, EPA believes the 

hfCLs for aldicarb, aldicarb sukfaxide, 

and aldicarb sulfone are set at the 

lowest level feasible. Consequently. for 

the reasons cited above the MU fm 

aldicarb, aldicarb sulfoxide and a1dkarb 

sulfone are established atO.aF)3m& 

0.004mg/t and 0.002 w/I,resgectiveIy. 

C.Pentachlomphmoi 

1.PentachtoropophenolMCLG 

On lanu;try 3Di199r.EPA pr0prtsed.m

MCLG of zem based on e drinlting 

water contaminantdasclificatiand 

Category I for pentacMomp8ed (PCBf.

Thisprepasa1 was based on &e 

cladcaticrn of PCPas a Class ES: 

carckegenunder EPA'w~ncm 

classification system (Le., probahta

human careinagenJ,WA, inrea&hg the 

Bzclasaificatien. determinedthat there 

6 

is sufficieut evirhce of car&agenicitr

for pentaehbraphemlfnom animal: 

stdies. This deeisionw3s qortedby

the ScienceAdwisoryi�har&im&ziL 

1990.TWBgcades of peSge&omphtmtA

(purified mmdd and technical 

grades) bo& inducedmultipk? tumm 

typm atdifferentdose leveb in malie 

and femalemi-. 

Summary of Comments 

Three cwgaaizahns submitted 

comments on the Asncy's ciarcinogen

classification for PCP. Alf three 

commentersbelieve that the 

carcinogenic evidence fromanimal 

studies is limited. These conrme&ers 

argued that FCPshould be CIassiSied in 

ClassC (with an MCLG of 02mg/IJ:

based on a National Toxicology bgmm

bioassay which detected a responseim 

only one species of B6�3F1mice. These 

commenterscited other negativerodent 

studies. One comnter calcdeted the 

cancer risk and claimed that EPA 

overestimated tHe came? risk by a 

factor of 10. 

EPAs Response to &e Comments 

After careful review of the CWUneRtS, 

EPA rea�firmed that pentachhapheno1

should be classified as E2carcinogen

(probablehuman caxinogen]. The 

studies cited by the commenterswere 

previously considered by the Agency

and no new infomation was-provided

by the commenter. 

EPA's �32classification is based on 

inadequate human data and snffacient 

evidence of carcinogenicity in&malls: 

statisticaZIy signiEcant increases in &e 

incidencesof multipre blohgicdy

significant tumor types @epatocelIular

adenomas and carcinomas, adrenal 

medulla pheochromocytQmasand' 

malignant pheochramocytomas, and/or

hemangiosarcomasand hemangiomas).

in one or both sexes of B6C3Fl mice 

using two diffkrent preparations Qf 

pentachlorophenol. Inadditian, a high

incidence crf two uncom0n +.mors 

[kemangiomaslhemangi~~comasand 

adrenal medulla pheachrtlmocytomsl 

was-observed with bath preparationsB

This classificationis supported by

mutagenicity data, whieh pmvide some 

indication that PCP has ciastagelpie

potential, 

Sever& studies in rodents cited by

cclrnmenters were unable fe dernonshte 

the caPeinoge&ity of PCP. Howaver, 

these studies wem all judged hy EPA tb. 

be limited and not usefirlfordrawing 

CO~C~US~OFIS concerning the 

carcinogenicity dPCP. "he sbdy

repocted by hea etiel. f3%?] used or& 

onede withan insuffjcientnmbm d 

animals, The study by Catiilina @m) 
’Federal Register Vo4. Si, No. 126 1 Monday, July 1,1991 / Rules and Regulatsons sizsa __ 

used an inappropriate route of 

administration with only one dose, and 

there was excessive mortality. The 

study by Schwstz et al. (1978) used an 

inadequate nimber 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 Bontwell and Boach I1959).

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 [mglkg) /day. This 

slope factor results ina unit risk of 3 x

lop6per [pg/lf. 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 pg/ 1 water. Thus, at 

the proposed MCL of 1 pg/l, the upper

bound risk of cancer is within the to 

HPrange. The statement in the January 

30 Federal Register [page 3808) that “A 

cancer unit risk estimate of 4.76 EX8 

caseslperson (pg/1] jyr’”should be 

deleted. 

EPA Conclusion 

EPA reaffirms the Class B2 

classificationfor pentachlorophenoland 

places pentachlorophenol in drinking 

water contaminant Category I. 

Consequently, the MCLG is set at zero, 

2. PentachlorophenolMCL 

The proposed MCL for 

pentachlorophenolwas based upon an 

analysis of several factors including: (1)

The effectivenessof the best available 

technology,granular activated carbon, 

in reducing influent concentrations to 

the proposed MCL of O.@X mg/l or less: 

[2) the feasibility{includingcosts) of 

applying BAT for large systems at 

approximately $10 per household per 

year; (33the 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/l with an 

acceptance lit of = 50%;and (4)

caparison of the individual lifetime 

carcinogenic risk of 3 x W-ofor the 

MCL to EPA’s target risk range of 10-4 to 

EPA requested comment an 

whether the MCL should be established 

at a level below the risk Ileuel. 

EPA received numerous comments on 

the PQL. Commenters noted (1)that EPA 

failed to identify the procedures it used 

to derive fhe.PQk(2) that EPA 

underestimated the analytical

variability at the MCL: and [a) that the 

propwed MCL will yjeld unacceptably

large laboratory performance 

variability. Several organizations

commented on the question of whether 

the PQL should be established at a level 

below the 10/ -6/ risk range. These 

cornmenters stated that 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/ -61 risk range. One 

commenter argued that EPA should 

establish the MCL at the 101-6l risk 

range (Le., 0.0003 mg/l).

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 ZOCs on January 

30,1991 (56 FR 35261. The procedures

EPA uses to establish PQLs 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/t

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/l. This 

was evident by the erratic laboratory

performance for concentrations that 

were less than O.o001mg/1.

Consequently, a revised PQL was 

assessed using the procedures described 

above. ThepentachlorophenolPQL is 

based upon the results of EPA and State 

laboratory data from Water Supply

Studies#22.25. EPA calculated the ‘50 

percent acceptance limits (Le., true 

value of fiesample *50 percent) based 

upon these Water Supply Study

statistics. The “plus or minus percent .of 

the true valwe” acceptance limits were 

derived taking into consideration the 

expected precision and accuracy. This 

range closely approximates the 95 

percent confidence limit estimated from 

the regression equation determined from 

the Water Supply Study data. EPA 

believes a PQL is achievable if the 

Water Supply Studies show that more 

than 75 percent of the lgboratories are 

within the target range. In the case of 

pentachlorophenol,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 0.001 mg/l. EPA subsequently

included data from Water Supply

Studies e26 and #27 in its analysis.

These data confirm that concentrations 

equal to or greater than the PQL of 0,001 

mg/l with an acceptance limit of +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 ‘58 

percent 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 

comrnenters 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 

results in variable labaratory

performance and (2) the analysis of 

Water Supply Study data demonstrates 

that laboratory performance can-in fact 

vary for some of the contaminants. As 

laboratories gain experience with the 

instrumentation and methodology, EPA 

anticipates improvements in laboratory

performance. EPA is continually

evaluatingongoing Water Supply Study

data as it b-comes available. These 

evaluations help determine whether the 

acceptance limits for regulated

contaminants should be amended as 

laboratory performance improves. 

As indicated previously, several 

commenters stated that they do not 

favor establishing MCLs below l0/-6/

Pisk This view is consistent with the 

Agency’s policy of set#in;g drinkhg 

water standards within the 10/-41 to

la/ -6/ lifetime risk range. In response 

to the commenter who supported setting

the MCL for PCP at O.OOO3 mg/l [i.e., 10/

-a/ lifetimerisk), we note this 

regulatoly level Is not feasible at this 

time because it is less than the PQL of

n.ooi mg/l. 

3 
D.Bariunr 
Federal Re@ster 1 Vcrl. 56, No. 126 J Monday, July 1, I991 J Rules and fegulakions 3M73 -

In 8 141.23[k][5)(ii], the second nitrate 

in the table with an acceptance Emif of 

percent, 20.4 mgli is changed to 

nitrite kl5percent 2 6.4 mg/l.

Revisions to 0 141.23Inorganic

Chemical Sampling and Ana1ytim.l

Requirements inadvertently eliminated 

inorganic sampling ad analyticaj

requirements �or the 9 inorganics listed 

in 8 142.11. EPA is reinserting the 

previous inorganic monitoring and 

analytical requirements by adding

paragraphs (1) through (9) to 8 14'1.23 

(previously 8 181.23 (a) through [e)).This 

cometion has the effect of retaining the 

previous inorganic requirements for 

cadmium, chromium, mercury, nitrate, 

and selenium lentil July 30,1992; for 

barium until Jamary 1,1993; and beyond

July 3Q,l992for arseak. 

Any alternate test procedures

previously approved *mder3 241.27 for 

both inorganic and organic

contaminants continue to be efhtive 

until July 30,1992 and January 1.1993, 

for barium 

in 0 141.%(e], Method 505 can also be 

used to analyze �orendrin and is added 

to the Est of ameptable methods. 

In 3 P41.Z4(h)(B)?.he sentence "after a 

muximum dffow qcarterly samples

show the system is in compliance * * *" 

is changed to read "After a minimum -of 

fom qtlartedy samples &ow the system

is in compliance * li *" (emphasis

added). Thereference to paragraph 

(h](12) is changed to QW%l).

In 5 141.24{h){11E)(iv)toxaphene is 

added to the list of'contaminants which 

can be analyzed using EPA Method 508. 

In 8 141.24(h)(lS)[i)the reference to 

paragraph @]{I31 is changed to 

paragraph ihfllit), The labratory certification 

sequireme& for the pesticides were not 

ificluded in&e final de.In 

0 14224{h)[19] EPA is inchding

laboratory certificationrequirements.

The perfurmawe requirements we 

discushied tisted on paa- 3550 to 

3552 of &e January %I, KWl Notice. 

In 0 141.62[b) the hrIct fer fluorde is 

changed from 4 mgll to 4.0 mg/l.

In 8 141.57(b)the reference to 

0 141.5qh) should be changed to 

8 241.62&].

In the footnotes to 9 143.4 ll2) and (13)

the updated versions of the methods 

~h~uid have been cited. In footnote p, 

cMltand.lsrpr 

EPA Method 200.7,version 3.1,April 

1990 is changed to version 3.2, August

In footnote 5,EPA Method 200.8, 

version 4.1, March 1990, is changed to 

version 4.3, August 1990;in footnote 6, 

!&PAMethod 200.9, version 1.0,April

1990,is changed to version 1.1, August 

199Q.

In 8 143.4112)a later version of the 

method isdted. EPA changes Method I305i-84 to Method I-305i-85. 

In 8 143.4(13)a later version of the 

method is cited. EPA changes Method I372l3-84 tQ E3720-85. 

IV. bdc Ady&s 

Executive Order 12291 requires EPA 

and other regulatory agencies to perform 

a regu1atory impact analysis (RIA] �or 

all ''major'' regulations, which are 

defined as those regulationswhich 

impose an annual cost to the economy of$loo million ormore, or meet other 

criteria. The Agency has determined 

that the proposed rule is a minor rule �OF 

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 wmments they make will be 

available in the publjc docket. 

In accordance with the Executive 

Order, the Agency previously conducted 

an assesslll(?llt of the benefits andcasts 

of regulatory alternatives as part of the 

Phase IIrule which was promulgated in 

the January 30,2991 Fedad Register.

This assessment in the Phase IIrule 

determined the impacts of this 

regulation as part ofthe Phase I1 rule 

and consequently these impacts are uot 

separately reconsidered in thisa~tice. 

A. Regziktmy �mpact 

EPA's analysis conducted under the 

proposed mie �or38 contaminants 154 

FR 22062, May Z2,19�@ indicates that 

approximately378 systems would 

violate the aidicarb MCt, raf 0ioo9 mg/i

based on the uncertainty in &e data 

base. EPA does not believe MCLs of 

0.004 mg/l for aldicarb sulfoxide and 

0.002mg/l for aldicarb sulfone will 

change this -timate. An additional 8z 

systemswould vMab M a fo? 

pentachforophend.

One corplmentm.@vidd%&ornatian 

disputhgEFWs estimate of the 378 

systems whkh mukd violate the MCb 

for aiditarb,a4dkarb sulfoxide and 

TA5LE 1.--REGUMTORY $MfACT 

-

aldicarb sulfone. This cornenter noted 

the relative lack of o~currencedata to 

estimate regulatory impact. This 

commenier assumed 1%of the systems 

(654systems) would exceed the MGL for 

aldicarb which is almost double the EPA 

estimate. EPA acknowledges the 

uncertainty in determining the 

regulatory impact and stated in the 

ProposedNotimthat %if&% of its 

estimate of 378systems(I@ to 567) 

systems may violate the MCL. Though it 

is conceivable that 654 systems may

violate the aidicarb 1Ww,-EpA points 

out that ihe regently compleied National 

Pesticide%mey did not detect ddicarb 

in any -well at beis exceeding-~.WO?l 

Wll. 

Several cornmienters stated that EPA 

should consider the impact uf these 

regwiatosy requirements on the 

collateral effects which trickle down 

through other regulatory programs such 

as Superfund, the Clean Air Act fCaA], 

stream water quality standards under 

the Clean Water Act and requirements

under the Resource Conservation and 

Recovery Act IRy=RA3. Wile EPA 

acknowledges that these secondary

impacts may occurathe purpose of 

today's action is solely to establish 

drinkingwater standards that public 

water systems mustcomply with. 

Conseguenily, EPA does not consider 

the cost ofsecondary impacts wMch 

may occur under the CAA, Super�und, or 

RCM. One cornmenfer alsosoted that 

these secondary impacts also affect the 

water supply industry by increasing the 

waste and disposal mts oftreatment. 

EPA is aware of this issuea d di$ 

include &e cost ofdagosa3.inthe 

Regulatory Impact hlysis

accompanying.&e Jmaary3i&1991�hi 

rule. 

As stated~mlier,EPA did not 

racon&& .themsts far the pnyposed

VOG inanizoriagq&ernients because 

thosecostsl#erewwinhEm3 

Phase -I�d egrPwnrlkgafed an&wmry 30, 

1991. Tibe rostsa�bday!aVOC 

monitor@ reqakemmts have virtually 

no impact on the total cost of VOC 

mwitoring primarily bemuse a single

analytical method can analyze a m 

of contaminants. Sampling for all VOC 

contaminantscanbe rondndet &e 

sametine. 

Annual Typical tf@net'+wSystemsin . treatment 3 4 cost 'UiotatiOa : (smiwion,yr) 'Small% ^Mediums ' ~p.4 ., 

i' 

Aldi~&,&~k~~~~lb~id~~ &&n!+.;-- ......................-....-.........-.._............_..-...A 37%i W) ae. +*a. 

PentilcMM.ophenol...................................................................................................... 625 $1 0 3s I ..19 
36274 Federal Register / Vol. 56, No. 126 / Monday, fuly 1, 1991 / Rules and Regulations 

TABLE1.--REGULATORY lMPAGT-COntinUed 

Annual Typical HH 1 treatment cost/system/year 

Contaminant Systems in treatment 

violation cost ($mi,lioniyr) Small Medium Large 

Barium...................................................................................................................................................... 0 0 '$230460 '$54-160 '$26-110 

I HH=houwhold. 

Small system serving 25-100 people.

Medium system serving 10,000-25,000 people. For Barium medium system serves 3,300-10.000 people. * Large systems serving more than 1,000,400 people.

Cost dependent upon BAT chosen. 

We estimate that approximately

280,000people will experience reduced 

exposure to aldicarb, aldicarb sulfoxide 

and aldicarb sulfone. Approximately 

960,000 people will have reduced 

exposure to pentachlorophenol. 

E. Regulatory Flexibility Analysis 

The Regulatory Flexibility Act 

requires EPA to consider the effect of 

regulations on small entities. 5 U.S.C. 

602 et seg. 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 XI 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 supportingthe 

final Phase I1 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 Pw-ts141,342, 

and 143 

Chemicals, Reporting and 

recordkeepingrequirements,Water 

supply, Administrativepractice and 

procedure. 

Dated June 17,1991. 

William K.Xeilly, 

Administrator,Environmental Protection 

Agency. 

For the reasons set forth in the 

preamble, title 40of the Code of Federal 

Regulations is amended as follows: 

PART 141-NATIONAL PRIMARY 

DRINKING WATER REGULATIQNS 

1.The authority citation for part 141 

continues to read as follows: 

Authority: 42 U.S.C.3Wf, 300g-1,3oOg-Z, 

300g-3,300g-4,300g-5,300g-6,30Oj-d and 

300j-9. 

2. In 4 141.6, paragraph (a) is revised 

and paragraph (8)is added to read as 

follows: 

8 141.6 Effective dates. 

(a) Except as provided in paragraphs 

(b) through (8) of this section, the 

regulations set forth in this part shall 

take effect on June.24,3977. * * * * * 

(8) The regulations contained in 

Section 141.8,paragraph (c) of the table 

in 14.12, and 141.62@)(1)are effective 

July 1,1991. The regulations contained in 

04 141.11(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 88 141.32(e)(16),(25)

through (27) and (46); 141.50(a)(15), 

(b)(4),(bI(5) and (bl(6);141.51(b)(3);

141.61(~)(2),(c1[3), (c)(4)and (c)(l6);

141.62@)(3)are effective January 1,1993. 

3. Section 141.11is amended by

revising the introductory text of 

paragraph (b) to read as follows: 

0 141.11 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 8 141.12, paragraph (c) in the 

table is revised to read as follows: 

0 141.12 Maximumcontaminantlevels for 

organic chemicals. 

* * * * . 

milligrams ! per liter 

(c) Total hihalomethanes (the sum of the 

concentrations of bromodichloromethme, dibrornochlorornethane, tribromomethane (bromoform) and trichloromethane (chloroform))................................. 

* * * * * 

5. Section 141.23 which was published

January 30,1991. (56 FR 3528) 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)(z);revising the table in (k)(4);

revising the table in (k)(5)(ii);and 

adding paragraphs (11, (m),In], (01, [PI,

and (9) to read as follows: 

0 141.23 Inorganic chemical sampling and 

analytieal 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 mmt be analyzed within 14 day;s

from each samplingpoint included in the 

composite. These samples must be 

analyzed for the contaminants which 

were detected in the composite sample.

Detectionlimits for each analytical

method are the following: * * * * * 

(i) * * * 

(1)For systems which are conducting

monitoring at a frequencygreater than 

annual, compliancewith 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 

oompliance immediately. Any sample

below the method detection limit shall 

0.10 
Reference{Method No.) 

Contaminant Methodology �PA 

ASTMP SMa 

i ufos.--.._.-.._.. I Bansmission Etecmnmoscopy~........_...._I__.-._. 

........... 

Chromium............................. 

. ....... 

1on chramatography...................................................................................... 300.0 

Nitrite......._..._..._-....-.-.s$em@mmttiC" ...................................... .l..-l--..l....--....--: 354.1 

Autmm6d-ieduction._....-.._._.._._l_l..__.I.I._._.... 359.2 D3867-SO ~ 418F 

Manual cadmirrrnreduction................................................................... D3867-90 418C 

: lon chromatography.................................................... ..- .......... Selenium ............................ :Atomic aboorption:gaseous hydride ._.__....l...l....-_..__I__._.....-

Atoniic absorpaion; fwme te&iaique............_.l-....l.....Y-ll-.-..........-. D3859-m ' 304' 

Metho& oi Chemical Analysis of Water and Wastes," �PA M iWitoring and Support laboratory. Cincinnati OH 45268fEW4-%33~4-79432@,

March 1983. Available from OFKl Wcations, CEFN. EPA. Cinckwati,OH 452fXL * Annual Rmk of ASWstandardg, Vd 11.01 Arnmban Society for Testing and Materials, 1916 Race Street, Phl@eiphia, P;P 19103. 

"Standard MethodsfDr the Emminationof Water andWastewater: Wth edition. Amemin Pub!ic Health Assoctahon. Amencan Water Wwks AssociatiDq Dlprrrer

PoMition Control Fsderatiwr,1985. 

QWertmd§.(nrc?eter~ of Inorganic Subtances in Water and Fluvial t+diienF." Techniiues of Water-Resources Investigations of the US. Geological Survey Books. ChapW Al. 1989 Opeo-Ae Repwt 85-495. Wailable Wm OpeMile Smces section, Western LWriWbon Brench,US.Geoloeicaf Survey, MS 306 

Box 24525. Denver Federal cent;v,Denver, CO 80225. 

"OrjonChide tC W%terand Was?6water Analysis"Form WeWwG/5880 p. 5 1985. Orion Research, Inc.. Cambridge, Mk 

2Q0.7A ''~n~~Coy!d PLaSrnaAtornic E-ission Analysis of &g Wker," Appendm to Method 200.7, March, 1987, US. EPA, EnvironmentalMonitodng and Support Laboratory, Cinmnati, DH 45p68. The additicht of 1 mL af 30% KO, to each $00mL of standards and samples CreqUkedMore analysis. Prior to dilution of the Se caiibratiq standard,add 2 mL of 9%HIG for each 100 mL of standard. * ''Adytical +.Whod Iw Determination of Asbestos Fibers in Water," EPA-600/4-83-043, september 1983, US EPA,Ein6ronmental Research Labwtw? 

Ath�?ns.GA 30813. ' 10"Waters13+f++hdforthe ionof NWe/FBltratein Water Using SingleColumn ton Chromatography. Method B-1011,Fjrmipore Corporafiorl, Watws 

ChrQmatography Owson, 34 Maple SzkI, MA 01757. 

fw app.cwed anatvticelpIocedurestor melab,the technique applicable to total metats mast be used. 

Public HeaZth Asaociatiow kmeri~anWater Works 

Asnociation.Water hWuiution Confro1 Federation 

1985. 

Techniquw cdWater-Resources hvevestipatianof 

the United StatesGeological Survey, Chapter A-2 

"Methodsfor Determiantionofhorganic 

Subdart- in WaterilndFiuvialSediments,"Beuk 

5,1979. Stock #014Mll-03177-9. Available from 

dithiocarbamate;or Method 2oo.TA 

Inductively Coupled Plasma 

Technique 5. 

* e * * * 

[M41 * * 

Superintendeatwf Docllmtnzs, US.Gove-n? 

printing Office,Wa&ngh3&3,DC204G2 

Annual EO& ofAWMStandards, part31 

Water, American SocietyhrTeshgand&&id& 

1918RaceStEeetPhiiadeiphia, Peansylwatpia39l@3. 

Appendix toMe&od 200-7,Mad 1987,US. 

EPA, Environmental MoaitoringSystems 

Laboratory, CincirmatbOH~%%ZI; 

1 

Prerenrative T,me

Apbestss

-............................................. I...,.......... 0301, 4°C I.......^................................. '-......-..-.----..I....­

cadmium '...-..-.-...-.-..-.--..-.....-.. ....- CWI HOs Ec pH <2 ................................. 

Chromium *..-.....-.---.--................................ ... Don WOS to pH <2................................. rConHOJ to pH <2 .................................. Fluorii(e .......--...-................ -..-..-............-...:#one ............................. .......................... kw .................................................... .W-tlcxto pW <2 .................................. Myhate: 

CMOrit't@d .- .............................................. Cwf. 4% ............................................. Non-chlorinated........................................... Con HpSOI to pH <2 .............................. Nitrite.................................................................... Cool, 4°C ................................................... 

t container * 

P UG ...............i..................................... : 

P DTG .................................................. Per G ................................................ P OT G ................................................ ,pw G ........................................... Por G ............................................. 

..P or G ...................................................... 28 days. 

P or G ....................................................... i 14 days. 

P or G ........................................................ 48 hours. 
Contaminant I Preservative I Contahr I Time' 

Selenium 1 ............................................................ Con HW to pH e2 ............................... P or G ........................................................ 6 months. 

(5)* * ' 

[i) * * 

(ii) * * 

Contaminant 1 Acceptance limit 

Asbestos............................. 2 standard deviations 

based on study

statistics 

Barium ................................. 3~15%at 20.15 mg/l

Cadmium............................. t20% at 20.002 mg/l

Chromium ........................... *15% at 2 0.01 mgil

Fluoride............................... *IO% at 1 to 10 mg/l

Mercxy;.............................. t30% at zO.0005 mg/l

Nitrate ................................. *IO% at 20.4 mg/l

Nitrite................................... t15% at 20.4 mg/i

Selenium ............................. f209b at 20.01 mgll 

question, exceeds the maxfmsm 

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, exempticln 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 Ievel 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 pursuaxit to 3 141.31 

and shall notify the public pursuant to 

f 141.32. 

(p) For the initial analyses required by 

paragraph (1) (I],(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 3years prior to 

the effective date of this part may be 

substituted at the discretion of the State. 

(q)Analyses conducted to determine 

compliance with 5 141.11 shall be made 

in accordance with the following

methods, or their equivalent as 

determined by the Administrator. 

(1)Arsenic-Method 206.2,Atomic 

Absorption Furnace Technique; or 

Method 1 206.3,or Method D2972-88B 

1 "Methods of Chemical Analysis of Wa!er and 

Wastes," EPA EnvironmentalMonitoring and 

Support Ihboratory. Cincinnati,Ohio 45288 [EPA61N!&W20), March 1983. Available from ORD 

Publications.CHU. EPf\, Cincinnati,Ohio 45268,For 

approved analytical procedures for metals, the 

technique applicable to total metals must be used. 

2 "Standard Methods for the Examination of 

Water and Wastewater." 16thEdition. American 

Public Health Association, American Water Works 

Association, Water Pollution Control Federation, 

1985. 

or Method 2 307A.or Method 3 I-1062­

85,Atomic Absorption-Gaseous

Hydride: or Method 1 206.4,or Method 

P-2972-88A, or Method 307B, 

Spectrophotometric,Silver 

Diethyldithiocarbamate; or Method 

200.7,Inductively Coupled Plasma 

Technique. 

(2)Barium-Method 208.1 or Method 

308,Atomic Absorption-Direct

Aspiration; or Method 208.2,Atomic 

Absorption Furnace Technique; or 

Method 8 200.7.Inductively Coupied

Plasma Technique. 

(3)Cadmium-Method 213.1 or 

Method D3557-78A or B, or Method 

310A,Atomic Absorption-Direct

Aspiration; or Method 213.2Atomic 

Absorption Furnace Technique; or 

Method 8 200.7,Inductively Coupledd

Plasma Technique. 

(4)Chromium-Method 218.1or 

Method 4 D 1687-77D3,or Method 31&, 

Atomic Absorption-Direct Aspiration; 

or Chromium-Method 1 218.2 Atomic 

Absorption Furnace Technique; or 

Method 8 200.7,Inductively Couple

Plasma Technique. 

(5)Mercury-Method 1 245.1,or 

Method 4I)-322389,or Method 320A, 

Manual Cold Vapor Technique; or 

Method 1 245.2,Automated Cold Vapor

Technique. 

(6) Nitrate-Method 352.1,or 

Method 4 D-992-71, or Method 353.3, 

or Method P-3867-79B, or Method 

4186,Spectrometric, Cadmium 

Reduction;Method 1 353.1,Automated 

Hydrazine Reduction; or Method 353.2, 

or Method 4 D-3867-79A, or Method 

41&F,Automated Cadmium Reduction. 

a Techniques of Water-ResourcesInvestigation of 

the United States Geological Survey, Chapter A-1, 

"Methods for Determinationof Inorganic

Rdbstances in Water and Fluvial Sediments," Book 

5,1979, Stock #02pOo1-03177-9. Available from 

Superintendent of Documents, U.S. Government 

Printing OEice, Washington, DC 20402. 

4 Annual Book of ASTM Standards. part 31 

Water, American Society for Testing and Materials. 

1976Race Street, Philadelphia. Pennsylvania 19103. 

'[Resewed& 

8 "Inductively Coupled Plasma-Atomic Emission 

SpectrometricMethod for Trace Element Analysis

of Water and Wastes-Method 200.7" with 

Appendix to Method 200.7entitled, "Inductively

Coupled Plasma-Atomic Emission Analysis of 

Drinking Water." March 1987. Available fromWA's 

EnvironmentalMonitoring and Support Laboratory.

Cincinnati,Ohio 45268. 
(7)Selenium-Method 270.2, Atomic 

Absorption Furnace Technique: or 

Method 1 270.3; or Method 1-1667-85, 

or Method 4 D-3859-79, or Method 

303F, Hydride Generation-Atomic 

Absorption Spectrophotometry. 

(8) Lead-Method 239.1 or Method 

D3559-78A or B, or Method 301-A I1 or 

III, pp. 148-152, Atomic AbsorptionDirect Aspiration; or Method 239.2, 

Atomic Absorption Furnace Technique; 

or Method * 200.7, Inductively Coupled

Plasma Technique. 

6. In 5 141.24, which was published

january 30,1991 (56 FR 3526) and which 

will become effective July 30,1992. 

paragraphs (e) and (fl are revised 

paragraphs (h)(8),(h)(12)(iv), (vi), (r-Ti).

and (h)(l3][i)are revised; and paragraph

(h)[39) is added to read as set forth 

below. In addition, paragraph (g), which 

was not affected by the Jan. 30,1991 

amendment, is amended by revising

paragraph (g) introductory text and 

adding [g)(8)to become effective July 30, 

1992. 

8 14’1.24 Organic chemicals other than 

total trihalomethanes,sampling and 

analyticall requirements. e * * * * 

(e) Analysis made to determine 

compliance with the maximum 

contaminant level for endrin in 

5 141.12(a) shall be made in accordance 

with EPA Methods 505, “Analysis of 

Organohalide Pestcides and Commercial 

Polychlorinated Biphenyl Products 

[Aroclors)in Water by Microextraction 

and Gas Chromatography” and 508. 

“Determination of Chlorinated 

Pesticides in Water by Gas 

Chromatography With an Electron 

Capture Detector.” The Methods are 

contained in “Methods for the 

Determination of Organic Compounds in 

Drinking Water,” ORD Publications, 

CEEU, EPA/600/&88/039, December 

1988. These methods are available from 

the National Technical Information 

Service (NTIS), U.S.Department of 

Commerce,5285 Port Royal Road, 

Springfield,VA 22161. The toll-free 

number is 1-800-336-4700. 

(9 Beginning on January 1.1993, 

analysis of the contaminants listed in 

5 141.6l(a)(1)through (18) for the 

purpose of determining compliance with 

the maximum contaminant level shall be 

conducted as follows: 

(1) Groundwater systems shall take a 

minimum of one sample at every entry

point to the distribution system which is 

representative of each well after 

treatment [hereafter called a sampling

point). Each sample must be taken at the 

same sampling point unless conditions 

make another sampling point more 

representative of each source, treatment 

plant, or within the distribution system.

(21 Surface water systems (or

combined surface/ground) shal1 take a 

minimum of one sample at points in the 

distribution system that are 

representative of each source or at each 

entry point to the distribution system

after treatment (hereafter called a 

sampling point). Each sample must be 

taken at the same sampling point unless 

conditions make another sampling point 

more representative of each source, 

treatment plant, or within the 

distribution system.

(3) If the system draws water from 

more than one source and the sources 

are combined before distribution,the 

system must sample at an entry point to 

the distribution system during periods of 

normal operating conditions (i.e., when 

water representative of all sources is 

being used). 

(4) Each community and non-transient 

non-community water system shall take 

four consecutive quarterly samples for 

each contaminant listed in 5 141.61(a) 

(2) through (18)during each compliance

period, beginning in the compliance

period starting January 1,1993. 

(5) If the initial monitoring for 

contaminants listed in 5 141.61(a) (1)

through (8)and the monitoring for the 

contaminants listed in 5 141.61fa)(9) 

through (18)as allowed in paragraph

(fl(l8) has been completed by December 

31,1992, and the system did not detect 

any contaminant listed in 5 141.61(a) (1)

through (la), then each ground and 

surface water system shalI take one 

sample annually beginning January 1. 

1993. 

(6) After a minimum of three years of 

annual sampling, the State may allow 

groundwater systems with no previous

detection ofany contaiminant listed in 

$141.61(a)to take one sample during

ea& compliance period.

(73 Each community and non-transient 

groundwater system which does not 

detect a contaminant listed in 

8 141.61(a) (1) through (18) may apply to 

the State for a waiver from the 

requirements of paragraphs (f)(5) and 

(fl(6)of this section after completing the 

initial monitoring. (For the purposes of 

this section, detection is defined as 

20.0005 mg/l.) A waiver shall be 

effective for no more than six years (two

compliance periods). 

(8) A State ma grant a waiver after 

evaluating the foTlowing factor(s):

(i) Knowledge of previous use 

[includingtransport, storage, or 

disposal) of the contaminant within the 

watershed or zqne of influence of the 

system. If a determination by the State 

reveals no previous use of the 

contaminant within the watershed or 

I3 

zone of influence, a waiver may be 

granted. 

(ii) If previous use of the Contaminant 

is unknown or it has been used 

previously, then the following factors 

shall be used to determine whether a 

waiver is granted. 

(A) Previous analytical results. 

(B) The proximity of the system to a 

potential point or non-point source of 

contamination.Point sources include 

spills and leaks of chemicals at or near a 

water treatment facility or at 

manufacturing, distribution,or storage

facilities,or from hazardous and 

municipal waste landfills and other 

waste handling or treatment facilities. 

[C) The environmental persistence

and transport of the contaminants. 

(D]The number of persons sewed by

the public water system and the 

proximity of a smaller system to a larger 

system. 

(E] How well the water source is 

protected against contamination. such 

as whether it is a surface or 

groundwater system. Groundwater 

systems must consider factors such as 

depth of the well, the type of soil, and 

wellhead protection. Surface water 

systems must consider watershed 

protection. 

(9) As a condition of the waiver a 

groundwater system must take one 

sample at each sampling point during 

the time the waiver is effective (Le., one 

sample during two compliance periods 

or six years) and update its vulnerability 

assessment considering the factors 

listed in paragraph (fl(8) of this section. 

Based on this vdnerability assessment 

the State must reconfirm that the system

is non-vulnerable. If the State does not 

make this reconfirmation within three 

years of the initial determination,then 

the waiver is invalidated and the system

is required to sample annually as 

specified in paragraph (51 of this section, 

(10) Each community and nontransient surface water system which 

does not detect a contaminant listed in 

8 141.61[a) (1) through (18)may apply to 

the State for a waiver from the 

requirements of (f)(5]of this section 

after completing the initial monitoring.

Systemsmeeting this criteria must be 

determined by the State to be nonvulnerable based on a vulnerability 

assessment during each compliance

period. Each system receiving a waiver 

shall sample at the frequency specified

by the State lif any). 

(11)If a contaminant listed in 

8 141.61(a](2) through (18) is detected at 

a level exceeding 0.0005 mg/l in any

sample, then: 
Y 
f 

Federal Register / Vot 66, No. 126 1 Monday, July 1, 1991 [ Rules and Regulations 

8 141.C1[aj@) through [IS]the 

laboratory must: 

[A) Analyze Performance Evaluation 

samples which include these substances 

provided by EPA Environmental 

Monitoring and SupportLaboratory or 

equivalent samples provided by the 

State. 

(B) Achieve the quantitative 

acceptance limits under paragraphs 

i[f)(l7(i)[C] and [D)of this section for at 

least 80 percent of the regulated organic

chemicals listed in 0 141.61[a] (4

through (181. 

[C] Achieve quantitative results on 

the analyses performed under paragraph

(flfl7)(i)(A]of this section that are 

within A20 percent of the actual amount 

of the substances in the Performance 

Evaluaiion sample when the actual 

amount is greater than or equal to 0.010 

mgll.

(D) Achieve quantitative results on 

the analyses performed under paragraph

(fj(l7)(i)(A)of this section that are 

within t40percent of the actual amount 

of the substances in the Performance 

Evaluation sample when the actual 

amount is less than 0.010 mg/l.

(E) Achieve a method detection limit 

of 0.0006 rngll, accordingto the 

procedures in appendix B oE part 138. 

[ii).To receive certification �orvinyl

chloride, the laboratory must: 

(A) Analyze Performance Evaliiation 

samples provided by EPA 

EnvironmentalMonitoring and Support

Laboratory or equivalent samples

provided by the State. 

[B) Achieve quantitative results on the 

analyses performed under paragraph

(f)(l7)[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 mgll, according to the 

procedures in appendix B of part 136. 

(D) Obtain certification for the 

contaminants listed in 0 141.61(a) (2)

through (18). 

(18)States may allow the use of 

monitoring data collected after January

1,1988, required under section 1445of 

the Act for purposes of initial monitoring

compliance. If the data ®enerally

consistent with the other requirements

in this section, the State may use these 

data (Le., a single sample rather than 

four quarterly samples) to satisfy the i initial monitoring requirement of 

paragraph (f)(4)of this section. Systems

which use grandfathered samples and 

did not detect any contaminant listed in 

0 141.61Ia) (1)through (181 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.

(201Each apprpved laboratory m~3t 

determine the method detection limit 

(WDL), as defined in appendix B to part

136, at which it is capable of detecting

VOCs. The acceptable MDL is 0.0005 

nag,& 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 complianceperiod.

[g) For systems in operation before 

January 1,1993, for purposes ob initial 

monitoring, analysis of the contaminants 

listed in 0 1;21.61(a](1)through (8)for 

purposes of determiningcompliance

with the maximum contaminant levels 

shall be conducted as follows: * * * * * 

(8) Until January 1,1993, the State 

may reduce the monitoring frequency in 

paragraphs (glil] and (g)[Z) of this 

section, as explained in this paragraph. * * * * * 

(h] * * * 

[8] Systems which violate the 

requirements of 8 141.61(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][i’J[Mii) of this section, * e * * * 

(121* ­ [iv) Method 508,“Determinationof 

Chlorinated Pesticides in Water by Gas 

Chromatographywith an Electron 

Capture Detector.” Method 508 can be 

used to measwe chlordane, heptachlor.

heptachlor epoxide, lindane, 

methoxychlorand toxaphene. Method 

508 can be used as a screen for PCBs. * * * * * 

(vi) Method 515.1, Revision 5.0, 

“Determinationof Chlorinated Acids in 

Water by Gas Chromatographywith an 

Electron Capture Detector” as revised 

May 1991. Method 515.1 can be used to 

measure 2,4-D, 2A5-W (Silvex) and 

pentachlorophenol.

(vii] Method 525.1, Revision 3.0 

‘’Determinationof 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. 

E5 

Contaminant Acceptance limits 

(percent) 

DECP.................................. It 40. 

EDB...................................... f40. 

Alachlor ............................... f45. 

Atrazine ............................... f 45. 

Cmbfuran.......................... f45. 

Chlordane............................ f45. 

Heptachlor................. ~ ........ f45. 

Heptachlor Epoxide........... f 45. 

Lindane................................ If 45. 

Methoxyctdor...................... -+ 45. 

PCBS (as

Decachlorobiphenyl). 0-200. 

Toxaphene......................... f45. 

Aldicarb ............................... 2 standard d8uiationh. 

Aldicarb sulfoxide............... 2 standard Uevialitml 

Aldjcarb sulfone.................. 2 standard deviations. 

Pentachbrophenol............. 50. 

2,4-0 .................................... * 50. 

2.4-TP.................................. -C 50. 

(ii) [Reserved] 

7. IA 8 141.32. paragraphs (e)ll6), (25)

through (27), and (46) are added to reed 

as follows: 

141.33 Public notification, * * * * * 

(e] * 

(16) Burium. The United States 

Environmental.Protection Agency (BPAJ 

sets drinking water standards @adhas 

determined that barium is a health 

iconcern at certain levels of exposureb

rhis inorganicchemical occurs nafutklly

in some aquifers that serve as sources of 

ground water. It is also used h oil and 

gas drilling muds, automotive paints,

bricks, tiles and jet fuels. It generally 

gets into drinkingwater after didsdving

from naturally occurringminetala in the 

ground. This chemicalmay danigge the 

heart and cardiovascular system, and is 

associated with high blood pressure in 

laboratory animals such as rats exposed 
to high levels duriq their lifetimes. In 

humam, W A h h &et e�f& hm 

barium on bkd pmsswze:should R& 

occur kl~wa prs peami&m[pp]in 

drinking water. W Ahasset the drinking 

water standard forbarium at 2 parts per

million kppm] to p~tectagainst the risk 

of these adverse health effects, Drinking 

water that meets the EPA standard is 

assaciated with little t~acme of thinrisk 

and is considered safe with respect ta 

barium, * *

** e 

(25)Al&&. The ExRieed Stah 

h\nfFQrrmf?Ilkd hd&hA@?aCy@PA) 

seta d&king waba stmdards a d has 

determined that al&cmh b a hedth 

concern at mtah levels Q� expure*

Aldicd k a wic$elyas& pstici$e:

Under certain soil and climatic 

conditions (e.&+mdy mil and.hi& 

raidall), aldimb may Lsb into~FQW~ 

water after normal agrkdtmrzlb

applications to crops such as potatoes or 

peanuts or may enter drinking water 

supplies as a result of surfam remoff. 

nis chmimlh&S kenshm trr 

damage the nervous system in 

laboratory animal SAa8 rats and 

dogs exposed to high levels. EPA has set 

the drinking wztter standard for al&& 

at 0.003 parts per million fspml ta 

protect against &e risk af adverse 

health effects. Drinking w&er that meets 

the EPA standad isassociated with 

little to none of this risk and is 

considered safewith respect tu aMmb. 

(26) Aldiccarb t~uI$oxide.TheUrnit& 

States Kvircmmentak Pratectian Agency 

(EPAJsets &inking water staa&mb ad 

has determined that aldicadii&&de 

is B health conm&at mtak levels of 

exposure. Aldicarb is a widely used 

pesticide. AIdicarb suIfoxEde in ground 

water is primarily a breekdwwn pdact

of aildicarb..Under certab mil at& 

ckimaticeonditiam [@.e.. sandy so& and 

high rainfall], aldicarb sulfoxidgmar 

leach into gsomd water after noma1 

agricultural appEimHms tacmps web 

as potatoes or peanuts or may enter 

drinking water supplies as a pedr d 

surface wff. This &emid has heen 

Shorn aQ thTIZL@ WCEBS Qmh 

lahat- hala sa& as rats and 

dogs exgored te~high h& EPA h a E& 

the &inkkg water standardjar a&& 

SpllliO~ateat Wm4 pa* per xdhiorr [p] 

tap~&& against the&Jc ofadverse 

health effeds.h);IinkjSllg,mtm hlBnEetS 

the EPA stmd;llb istwmcha 116th 

little tamme dahisrisk &is 

l33msidd safe with mg-*&&c& 

sulf&& 

(n)iL&J&yrb~-atERitecil 

StatesEnvmmme;ntalprOWs~

(EPA)s&Bs drimhg water tatadda aad 

has Clarter- tibt alakmb mHmeis 

Contaminant WLa 

w 

laSection 

adding to the 

fc)(3),(c][4Jvand (c)@@to maad as 

fahs: 

0 141.M brimw c-kuekorganic contmhan& * * * * * 

* 

CAS hloi cwi+amicaarb (Z 

* c t * I 

(2)1?&OW?.............. Aldlcerb......-.........-... 0.0110 

(3)1-74 ........... sylloxicl$-- @$md

t* wIt?M%?-4--..".* ..-- am 6 * 6 I . (16) 87-86-5 .............. PentaMnmphd.-. Qool 

(1) Fluoride.................................................. 4.0 

* c * ­ (3) WiiJRt..................................................... 2 

t . t 0 * 

**** * 
Federal Register / Vol. 56, No. 126 / Monday, July 1, 1991 / Rules and Regulations 90281 

PART 142-NATIONAL PRIMARY 

DRINKING WATER REGULATION§ 

IMPLEMENTATION 

12.The authority citation for part 142 

continues to read as follows: 

Authority: 42 U.S.C.3*, 3OOg-l.3OOg-2, 

300g-3,300g-4,300g-5,300g-e. 3mj4 and 

300j-9. 

13.In 0 142.57,which was published

January 30,1991(56FR 3526)and will 

become effective July 30,199~, 

paragraph (b) is revised to read as 

foIlows: 

0 142.57 BottledWater, Point-of-Use. e * * * * 

(b) Public water systems using bottled 

water as a condition of obtaining an 

exemption from the requirements of 

88 141.61 (a] and (c) and 0 141.62’(b] 

must meet the requirements in 

8 112.62(g).

* * * * * 

PART 143-NATIONAL SECONDARY 

DRINKING WATER REGULATtONS 

14,The authority citation for part M3 

continues to read as follows: 

Authoriw42 U.S.C.3oog-1(e),3ooj-4 and 

3ooi-9. 

15.In 0 f43.4,which was publ-i-shed

January 3 a1991(58 FR 3526)and which 

will become eE&ve Xuly 30,1992 

paragraphs [b] (121and (13)are revised 

to read as follows: 

$143.4 Monitoring.

* * * * * 

(h) * * * 

(12)Aluminum-Method 202.1 

Atomic Absorption Technique-Direct 

Aspiration: or Method 2 3064 or 

Method 9 I-305i-85,or Method 1 202.2 

Atomic Absorption-Graphite Furnace 

Technique; or Method 304;or Method 4 

“Methodsof ChemicalAnalysis of Water end 

Wastes.” EPA, Envimnmental Monitoring and 

Systems Laboratory, Cincinnati, OH 45268, EPA 

600/4-79420, March. 1983.Available fmm ORD 

Publication,CERI,EPA, Cincinnati, OH 45268 

2 ”Standard Methods for the Examination of 

Waler and Wastewater.” 16thEd., AmericanPublic 

Health Association. American Waterworks 

Association, Water Pollution Control Federation, 

1985. 

“Methods for the Determination ufhrganic 

Substances in Water and Fluviai Sediments,” 

Techniques of Water-Resources Investigations of 

the United States Geological Survey Books,Chapter 

Al. 1985.Available !?om Opee File Services 

Section,Western Distribution Branch, U.S 

Geological Survey, Denver Federal Center, Denver, 

co80255. 

*%?terminationof Metals andTrace Elements 

.byEnductivelyCoupled Piasma-AtomicEaission 

Spectrometry,”Method 200.7, version3.2.Awst 

1990,EF’A hvironmental MonitoringendSystems 

Labopatory, CincinRati. OH 

200.7 Inductively-Coupled Plasma 

Technique: or Method 200.8 

Inductively Coupled Plasma-Mass 

Spectrometry or Method 200.9Platform 

Technique: or Method 3120B 

Inductively-Coupled Plasma Technique. 

(131Silver-Method 272.1 Atomic 

Absorption Technique-Direct

Aspiration; or Method 2 324A;or 

Method 9 1-3720-85;or Method 2722 

Atomic Absorption-Graphite Furnace 

Technique: or Method 304;or Method 

200.7Inductively-Coupled PlasmaTechnique; or Method 6 200.8 

Inductively-Coupled Plasma-Mass 

Spectrometry; or Method 200.9 

Platform Technique: or Method 312OB 

Inductively-Coupled Plasma-Technique. 

[FR Doc. 91-15564 Filed 6-28-91;8&5 arnl 

BILLtNO CODE 6580-504 

6 “Determinationof and Trace Elements in Water 

ant! Wastes by InductivelyCouple13Plesma-dJlrrSs 

Spectrometry.”Method 200.8, version4.3, &qp&, 

1990,EPA. EnvironmentalModioringaad Sgetenrii 

Laboratory, Cincinnati,OH 4526&&&&iie fpanr 

ORD Publication, CERI, EPA. Cincinn&.WR&Z@3. 

6 “Determinationof Metals and Trace Elements 

by Stabilized Temperature Graphite &mace 

Atomic Absorption Spectrometry,” Me&a&do0.3, 

version 1.1, August, 1990.@A, Envirenmentd 

Monitoring and Systems Laboratory+Cincima%i.OH 

45268. 

7 “Standard Methods for the ExaRllnatien ol 

Water and Wastewater,” 16th e&, Anxerican %krk 

Health Association, American W e d 

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