## -- Wednesday July 8, 1987



# Part 

# II



# Enwironmental Protection Agency

40 

### CFR Parts 141 and 142
National Primary Drinking Water Regulations-Synthetic Organic Chemicals; Monitoring for 

### Unregulated Contaminants; Final Rule

### 25690 

### Federal Register 

## I Vol. 52, 

### No. 130 

## 1Wednesday, July 8, 

### 1987 

### ] Rules and Regulations

ENVIRONMENTALPROTECTION AGENCY

40 CFR Parts 141and 142

[WH-FRL-3213-81

National Primary Drinking Water Regulations; Synthetic Organic Chemicals; Monitoringfor Unregulated Contaminants

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final Rule.

SUMMARY:In this notice, EPA is promulgating National Primary Drinking Water Regulations (NPDWRs)for certain volatile synthetic organic

. chemicals (VOCs). Specifically,this notice promulgates maximum contaminant levels (MCLs) for: Trichloroethylene, carbon tetrachloride, 1.1,l-trichloroethane. vinyl chloride, 12­ dichloroethane, benzene, 1,ldichloroethylene, and paradichlorobenzene. The NPDWRs also include monitoring,reporting and public notification requirements for these eight VOCs. EPA is also publishing the maximum contaminant level goal (MCLG)for para-dichlorobenzene. This notice specifies the best available technology (BAT)upon which the MCLs

are based and BAT for the purpose of issuing variances. In this notice, the Agency is alsopromulgatingprocedures by which systems may obtain variances and exemptions from these NPDWRs. In addition to the 

### NPDWRs for the eight VOCs, the Agency is also promulgating monitoring requirements for 51 other synthetic organic chemicals which are not regulated by NPDWRs.

EPA proposed NPDWRs, including MCLs, for the eight VOCS listed above

on November 13.1985 (50

### FR 46902). New data 

### on the toxicology of paradichlorobenzene became available after the November 13 notice which changed its health effects classification. EPA proposed to amend the MCLG and reproposed the MCL for this contaminant 

### on April 17,1987 (52FR 12876). based on this new information.

EFFECTIVE DATES This regulation is effectiveJanuary 9,1989, except for 

### 0

### g 141.24(g), 141.35, and 141.40.The information collection requirements in
40 CFR 141.24(g), 141.35, and 141.40 are effectiveJanuary 1,1988, if the information collection request is clear by the Office of Management and Budget (OMB) and an OMB clearance number is assigned prior to that date. If not, the requirements will be effective when OMB clears the request and a notice is published. In accordance with 40 CFR23.7. this regulation shall be considered 

### final agency action 

### for the
purposes ofjudicial review at 1f10 pm eastern daylight savings time 

### on July

### 22
1987.

ADDRESSES: Public comments on the proposal, major supporting documents. and a copy of the index to the public docket for this rulemaking are available for review during normal business hours
at the EPA, Room 2904 (rear) in the Public Information Reference 

### Unit 401 

### M Street, SW., Washington, DC 20460. A complete copy of the public docket is available

### for inspection at EPA 

### m Washington, DC by appointment by contacting 

### Ms.Colleen Campbell 202/ 382-3027.

FOR FURTHER INFORMATION CONTACT: Joseph A. Cotruvo,Ph.D., 

### Director. Criteria and Standards Division. Office of Drinking Water (WH-550), US. Environmental Protection Agency. 4M 

### M Street, 

### SW., Washington, 

### DC 20460,202/ 382-7575, or one of the EPA Regional Office contacts listed in "Supplementry Information". Information may 

### also be obtained from the EPA DrinkingWater Hotline. The toll-free number is 800/426­
4791 and the Washington, DC number is
382-5533.
SUPPLEMEWARY INFORMATION:

EPA Regional Offices I. 

### JFK Federal Bldg., Room 2203,Boston, MA 02203,Phone: (617)565-3610, Jerome Healey 

### II. 26 Federal Plaza, Room 824,New

York, NY 10278,Phone: (n2)Z64-1800, Walter Andrews In. 841 Chestnut Street, Philadelphia, PA

19107,Phone: (215)597-9873,

### Jon Capacasa 

### IV. 345 Courtland Street, Atlanta, GA

30365,Phone: (404)347-2913,William Patton 

### V. 230 

### S.Dearborn Street, Chicago, 

### IL

60604, Phone: (312)353-2650, Joseph Harrison 

### VI. 1445 Ross Avenue, Dallas, 

### TX 75202,

Phone: (214)655-7155, Thomas Love 

### VII. 726 Minnesota Ave., Kansas City,

KS 66101,Phone: (913)236-2815, Gerald 

### R. Foree VIII. One Denver Place, 999 18th Street,

Suite 300,Denver, CO 80202-2413, Phone: (303)293-1424,Marc Alston 

### E. 215 Fremont Street, San Francisco, CA 94105,Phone: (415)974-0763, William Thurston 

### X. 1200Sixth Avenue, Seattle, WA

98101,Phone: (206)4424092,Richard Thiel

Abbreviations Used in This Notice

BAT Best Available Technology BTGA: Best Technology Generally

Available 

### CWS: Community Water System 

# i

EMSL: EPA Environmental Monitod

and Support Laboratory (Cincinne GAC: Granular Activated Carbon 5 

### LOQ:Limit of Quantitation MCL Maximum Contaminant 

### Level

(expressed as rng/l)* MCLG Maximum Contaminant 

### hvi

Goal h4DL Method Detection Limit mgd: Million Gallons per Day NIPDWR: National Interim Primary

Drinking Water Regulation NPDWR: National Primary Drinking

Water Regulation NTNCWS: Non-transient Non-


### ,

communityWater System pdcb: para-Dichlorobenzene WE:Point-of-Entry Technologies POU. Point-of-Use Technologies PQL Practical Quantitation Level PTA: Packed Tower Aeration PWS: Public Water System PWSS: Public Water System Supem RMCL RecommendedMaximum

Contaminant Level SDWA: Safe Drinking Water Act, 

### or

"Act." asamended in 1986 THMs: Trihalomethanes URW.Unreasonable Risk to Health VOC: Volatile Synthetic Organic

Chemical

'1.0~ micrograms (ug) = 1 milligram (

Table of Contents
I. Summary ofToday's Actions 11. Background

A. StatutoryAuthority B. RegulatoryBackground C. Public Comments on the Proposal III. Explanation of Today's Actions

A. Non-transientNon-communitv Watt

System B. MCLG for Dara-dichlorobenzene C. MCLSfor VOCS

1. Treatment Technologies 2. costs 3. Other Factors 4. Summaryof MCL Determinations D. Other TreatmentTechnologies E Analytical Methods and Compliancc

Monitoring Requirements
1. Analytical methods 2 Compliance Monitoring Requireme] F. Laboratory Approval G.Variances and Exemptions

1. Variances 2. Exemptions 3. Central Treatment vs. POU/Bottled Water H. Public Notification 1. Reporting Requirements J. Total Volatile Synthetic Organic

Chemicals (TVOC) K. Monitoring for Unregulated

Contaminants IV.Effective Dates V. Impact Analyses VI. References and PublicDocket3 $ 

### $-. Federal Register 

### f Vol. 

## * vstem Monito% Cincinnati :arbon

for ,ntLevel tMe

iant Level Requirements
lit P 4-Analyses within the Acceotancc!

1Y Primary 

## hornDrinking Water Using Pack2

n rower Aeration or GranularActivated Drinking

on1

e maryof Today's Action logies Kcability jgies Level ,e requirements of this notice apply



### n Icommunitywater systems (CWS) ion-transient non-community water

1Supervisio !ms(NTNCWS). In-transient non-community water mum !fernsare those which regularly serve ksame 25 or more persons at least 6 r Act, or 

### th pthsper year. 5 

### idMCLG:

x oHealth
; a-dichIorobenzene-o.W5 mg/l :anic 

### ;I MCLs:
1enzene-0.005mg/l illigram [ql' rarbon tetrachloride4.m mg/l ,2-dichloroethane-0.005 mn/l

oposal Jns nity Water Section 1412

### ofthe SD WA

izene acked tower aeration (PTA)or @nular activated carbon (GAC)for all

dated VOCs, except vinyl chloride. '�A for vinyl chloride. tQther effective removal technologies :ies kat treat all of the drinking water in a rnpliance 

# 1. mpliance.


### PTunderSection 1415 (Variances):

me technologies are BAT as those bder Section 1412.

/Bottled

De basic monitoring requirements
anic 

### @ as follows: Quarterly samples for each ground nd surface water source. Fomposite samples of up to five !Wces are allowed.

t I

Determination of compliance is established asfollows: Both ground and surfacewater systemsmust calculate a running average of the concentration of each VOC, over one year, taking at least

one sample per quarter, for each source.

All samples must be used. For ground waters, the State as primacy agent may reduce the sampling frequency ifregulated VOCs are not detected in the first sample. The minimum possible monitoring requirement for compliance is one sample per source.

Repeat monitoring varies from quarterly to once per five years. States determine repeat monitoring requirements based on: (1)Whether or not VOCs have been detected in the initial sampling, and (2) the vulnerability of the system to contamination (determined by the State). AnalyticalMethods.

1.EPA Method 502.1-Volatile Halogenated Organic Compounds in Water by F'urge and Trap Gas Chromatography.

2. EPA Method 502.2-Volatile Organic Compounds in Water by Purge and Trap Gas Chromatography with Photoionization and Electrolytic Conductors in Series.

3. EPA Method 503.1-Volatile Aromatic and Unsaturated Organic Compounds in Waterby Purge and Trap Gas Chromatography.

4. EPA Method 504-12- Dibromoethane and 1,2-Dibromo-3­ chloropropane in Waterby Microextraction and Gas Chromatography.

5. EPA Method 524.1-Volatile Organic Compounds in Water by Purge and Trap Gas Chromatography/Mass Spectrometry.

6.EPA Method 524.2-Volatile Organic Compoundsin Water by Purge and Trap Capillary Column Gas Chromatography/Mass Spectrometry. Labomtory Certification Criteria Vinyl Chloride:
k 40 percent at any concentration All others:
It 20 percent 

## > 0.010 mg/l i- 40 percent 

### 5 0.010 mg/l Point-of EntryDevices [POEj,Point-ofUseDevices {POUj, andBottled Water

POE may be used to achieve compliance with MCk,however, POE is
not BAT. 17 

## / Rules and Regulations 

### 25691

POU and bottled water cannot be used to achieve compliance with the MCLs, however, either may, at State discretion, be a condition of granting a variance or exemption.

VariancesandExemptions

Prior to issuing a variance or exemption, the Statehas the authority to require the public water system to implement additionalinterim control

measures if an unreasonable risk to health exists: among other mitigation techniques, Statesmay require installation of point-of-use devices or distribution of bottled wafer to each
customer as measures to reduce the health risk before granting a variance or exemption.
Monitoring for Unregulated Conturninants

One sample per source is required
every five years.

Systems sample according to the procedures and schedules established for VOC compIiance monitoring.

Monitoring for the 50 unregulated contaminants is as specified below:

List 1: monitoring required for all systems (34contaminants).

List 2: monitoring required for vulnerable systems (2 contaminants).

List 3: monitoring required at State discretion f15contaminants).

Repeat monitoring frequency: Every five years.

EPA will specify a new list before repeat monitoring is required (within five years).

11. Background

A. StatutoryAuthority

Section 1412of the Safe Drinking Water Act. as amended in 1986 ("SDWA' or "the Act"), requires EPA to publish Maximum Contaminant Level Goals (MCLGs) and promulgate National Primary Drinking Water Regulations (NPDWRs) for contaminants in drinking water which may cause any adverse effect on the health ofpersons and which are 

### known

or anticipated to occur in public water systems. Under Section 1401. the 

### NPDWRs are to include Maximum Contaminant Levels (MCLs) and "criteria and procedures to assure a supply of drinking water which dependably complies" with such MCh. Under Section 1412(b)(7)(A), if it is not economically or technically feasible to ascertain the ievel of a contaminant in drinking water. EPA may require 

### the use of a treatment technique instead of an MCL1.MCLs. MCLGs, and BAT
EPA is to establish MCLGs at the level at which no known 

### or anticipated adverse effects on the health of persons

occur and which allow an adequate margin of safety. MCLGs are nonenforceable health goals. EPA published MCLGs. previously called RecommendedMaximum Contaminant Levels (RMCLs). for trichloroethylene, carbon tetrachloride, 1.1,1­ trichloroethane. vinyl chloride, 12­ dichloroethane,benzene, 1,ldichloroethylene,and paradichlorobenzene 

### on November 13,1985. The Agency reproposed the MCLG for pDCB 

### on April 17,1987(52 

### F’R 12876), based 

### on new health assessment data.

MCLs are enforceable standards which the Act directs EPA to set as close to the MCLGs as feasible. “Feasible”means feasible with the use of the best technology, treatment techniques, 

### or other means which the Administrator finds available (taking
cost into consideration) after examination for efficacy under field conditions and not solely under laboratory conditions.

### Also, the SDWA requires the Agency to identify the best available technology (BAT) which is feasible for meeting the MCLfor each contaminant.

### NPDWRs are to be amended whenever changes

~ technology 

### or other means permit greater protection of the health of

. persons, and the regulations are to be reviewed no less frequently than every three years.

2. Variances and Exemptions

Section 1415authorizes the State (the
term “State” is used in this Preamble to

mean the State agency with primary enforcementresponsibility for the public
water supply system program, 

### or “primacy,” 

### or EPA if the State does not have primacy] to issue variances from NPDWRs. The State may issue a variance if it determines that a system cannot comply with an MCLdespite application of the best available

. technology (BAT). Under Section 1415, EPA must propose and promulgate its findingof the best technology, treatment techniques, or other means available for each contaminant (BAT), for purposes of Section 1415variances. at the same time that it proposes and promulgates a maximum contaminant level for each such contaminant. EPA’s finding of best technology, treatment techniques, or other means available for purposes of issuing variances may vary among systems, depending upon the number of persons served by the system or for other physical conditions related to engineering feasibility and costs of complying with MCLs, asconsidered appropriate by EPA. The State may not issue a variance where an unreasonable risk to health exists. When a State grants a variance, it must at the same time prescribe a schedule for (1) compliance with the NPDWR and (2) implementation of such additional controlmeasures as the State may require.

Under section 1416(a),the State may exempt a public water system from any MCL 

### or treatment technique requirementif it finds that (1)due to compellingfactors (whichmay include economicfactors), the system is unable

. to comply, (2) the system was in operation on the effective date of the MCL or treatment technique, or, for a

newer system, that no reasonable alternative source of drinking water is available to that system, and (3)the exemptionwill not result in an unreasonable risk to health. Under section 1416(b),at the same time it grants an exemption,the State is to prescribe a compliance schedule and a schedule for implementation of any required interim control measures. For exemptionsfrom a NPDWR promulgated after enactment of the SDWA amendments, such as the 

### NPDWRs for the VOCs promulgated in this notice, the compliance date must be no later than 12months after the date of issuance of the exemption. However, the State may extend the final compliance date for a period not to exceed three years after the date of issuance of the exemption if the public water system establishes that it is taking all reasonable steps to meet the standard once: (11the system cannot meet the standard without capital improvements which cannot be completedwithin the period of such

. exemptions: (2) in the case of a system which needs financial assistance for the
necessary improvements,the system has entered into an agreement to obtain such financial assistance; or (3)the system has entered into an enforceable agreementto become part of a regional public water system. For systems that

serve 500 or fewer service connections and which need financial assistance to

come into compliance, the State may
renew the exemptionfor additional twoyear periods if the system is taking all practicable steps to meet the requirements in the previous sentence.

3. Primacy.

Today’s regulation is one of many which EPA will promulgate during the
next few years, as required by the 1986 Amendments. 

### To retain primary enforcement responsibility (‘primacy”) for the public water system supervision program, States must revise their Water System Supervisio

program, including the changes contained in any new regulations. the effective date onward.

### 52, 

### No. 130 

## / Wednesday, July 8. 

### 1987 

## / Rules and Regulations

tion EPA plans to specify, as revisions to 40 CFR Part 142,

nts containedin this

,must comply with Federal requirements. Failure by a State with primacy to establish its own requirementsdoes not exempt a system from the Federalrequirements and systems which violate a Federal requirement contained 

### in this regulation will be subject to Federal enforcement. Public water systems located in States with primacy should,however,reporf analytical results and all other infomation required by this regulation
to the State even if the State has not yet adopted the requirementsof the regulation. It will be the responsibility 

### of the State, in such cases. to forward information to EPA.

4. Monitoring, QualityControl, and Records

Under section 1401(1)(D) 

### of the Act, NPDWRs are to contain “criteria and procedures to assure a supplyof drinking water which dependably complies with such maximum contaminantlevels; including quality control and testing procedures to insure compliance with such levels



# . . 

# . .”

### In addition, Section 1445 states that, “every
person who is a supplier of water.


# . . shall establish and maintain such records,make such reports, conduct such monitoring and provide such information as the Administratormay reasonably require by regulation to assist him in establishing regulations,



# . . .in evaluating the health risks of unregulated contaminants 

### or in advising the public of such risks.” Section 1445 also requires EPA to promulgate regulations requiring every public water system to conduct a monitoringprogram for unregulatedcontaminants.

5. Non-transient Non-community Water Systems

Public water systems are definedin the Act at section 1401[l)(D)(4) asthose systems which providepiped water for human consumption and have at least 15 connections

### or regulady serve at least 25 people. 

### The category “public water system”is composed 

### of community and non-community water systems. The community water system is one which

serves at least 15connectionsused by year-roundresidents 

### or regularly serves at least 25 year-roundresidents (40 

### CFR 1412).Non-community systems, by definition, are all other water systems. Non-community systems include transient systems leg.. campgrounds, gas stations) and non-transient systems (e.g., schooL, workplaces,hospitals which have their ownwater supply and

serve the samepopulation Over six months of a year), asexplained in more detail later. 6. PublicNotification
Section 1414(c)of the Act requires the

owner 

### or operator of a public water system which fails to comply with an applicabie maximum contaminantlevel

or treatment technique requirement, testing procedure. 

### or section 1445(a) monitoring requirement to give notice to the persons served by the water system. Owners and operators of public water systems for which variances 

### or exemptionsare in effect, 

### or which fail to comply with the requirement of any scheduleimposed pursuant to a variance 

### or exemption, must also give notice. Section 1445(a)(5)also requires public water systems to notify the
persons served by the water system and the Administratorof EPA of the availability of the results of monitoring 

### for unregulated contaminants.

B.RegulatoryBackground



### On June 12,1984 (49FFt 243301,EPA proposedMCLGs for the eight VOCs covered in today’s notice: Benzene, 

### carbontetrachloride, 1,2dichloroethane.

­ trichloroethylene, kldichloruethylene, l,l,l-trichloroethane, paradichlorobenzene, and vinyl chloride. 

### On November 13,1985,EPA publishedthe final MCLGs and proposedMCLs for these eight VOCs I50

### FR 46880 and 50 FR 46902). Detailed discussions of the history 

### of the regulation of 

### VOCs in drinking water together with information on occurrencein drinking
water and any adverse effects of human
exposurewere presented in these notices. This background is summarized below. EPAproposed to amend the MCLG for para-dichlorabenzene(p

### DCB) and reproposedthe MCL for p DCB on April 17,1987 (52FR 12876).

1. MCLGs, MCLs, and Monitoring

In the November 13,1985, notice for substances

### considered to be 

### knownor probable 

### human carcinogens, EPA set the MCLGs at

### zem. For substances it did
not consider

### known 

### or probable human carcinogens, EPA set the MCLGs based
upon chronic toxicity data. Table 1 summarizes the final MUS 

### for these VOCs. The 

### ChemicalManufacturers Association, the HalogenatedSolvents Industry 

### Alliance,and the Natural Resources Defense Council each filed petitions for review

### of one or more of theseMCLGs. These petitions are pending before the 

### US. Court of Appeals for the District of Columbia Circuit

The establishmentofan MCLG at

zem does not imply that actual harm would necessarily 

### occurto humans at a level somewhat above zero. but rather that zero is an aspirational goal, whichincludes a margin of safety, within the day but throughout much of the year, comments received and the

context of the Safe Drinking Water Act. and often for many years. responses are presented in the

. MCLs, even though set at levels above At the same time that EPA proposed document "Summary of Corne aspirational MCLGs,based otl the MCLs, it also proposed minimum EPA responses on the Proposed feasibility considerations, are also compliance monitoringrequirements considered safe levels that are consistingof one initial round of protective of public health. monitoring to determine the extent of

EPAproposed the 

### MCLs for the eight contamination and certain follow-up VOCs based upon an evaluation of (1) monitoringrequirements if the initial the availability and performance of round of monitoring indicated VOC

treatment technologies [BestTechnology contamination.The November 1985 GenerallyAvailable (BTGA),under notice also proposed monitoring Sections 1412 and 1415,was identified requirements for 51 additional

asFTA or GAC], (2)the availability, unregulated contaminants [all VOCs) performance, and cost of analytical under Section 1445.These requirements methods, and (3)an assessment of the were very similarto the compliance

costs of application of various monitoringrequirements proposed for technologies to remove VOCs from the eight MCLs. The major difference drinking water to various. was that for the unregulated
concentrations. Table 1 summarizes the contaminants only one round of
final MCLGs and the proposed and final monitoring was proposed (the
MCLs that EPA is promulgating in this compliancemonitoringrequirements
rule. called for repeat samplingranging in frequency from quarterly to every 5 TABLE FI FINAL MCLGS AND PFiOPoSED AND years, depending on the priormonitoring MCLS FOR THE v%S results and a determination of a FINAL system's vulnerability to

cwnpwnd Final contamination).

2. Reporting and PublicNotice

Benzeoe

....... 

### .....-.

~ zero EPA also proposed reporting and Vinyl chloride Zero carbon tetrecMonde zero public notice requirements for VOCs in

1.2-D~loroethane



### ......."


### ......... Zero the November 1985 notice. The proposed A.Non-Transient Non-Community Trichloroethylene

### ......-"-..".... Zero requirements were identical to those pDichlwobemene'

### ......."........ 0.075 1.1-Dichlwoelhylene .W7 currently in place under the National 

### Water Systems

1.1.1-TricNwoelhsne.....



### ......... .20 Interim Primary Drinking Water In the November 1985 notice,

'~eproposed on Apll17.1987. at zero and 0.005. Regulations (now simply "National proposed to redefine the term Primary Drinking Water Regulations"). As described above, the Agency No change in the public notice proposed to amend the MCLG and requirements was proposed at that time. reproposed the MCL at 52FR 12876 

### For unregulated contaminants, the (April 17,1987)for para-dichlorobenzene proposed regulations would have (whichis the common name for 1,4- required the PWS to notify its dichlorobenzene). These proposals were consumers of the availability of the based upon results of a new National analytical results of the unregulated Toxicology 

### (NTP) study. Based on a contaminant monitoring and to submit a preliminary assessment of the total representative copy of each public weight of evidence of the toxicological notice to the State. 

### In addition, the studies, EPA proposed to reclassify p- results of the monitoring were to be dcb as a Group B2 substance under the submitted to the State. Agency's Guidelinesfor Carcinogen 

### In response to the SDWA Risk Assessment at 51 

### FR 33992 amendments 

### of 1986,which revised the (September 24,1986).This notice on p- public notificationrequirements in dcb also indicated that EPA was Section 1414(c),EPA recently proposed consideringclassification of pdcbin changes to public notification Group C instead 

### of B2. The Agency requirements in 52 FR 10972 (April 6, asked for public comment on the 1987). That proposal includes specific appropriate classification based on the explanations of the potential health weight of evidence. risks of exposure to the eight VOCs in

In the November 1985notice, EPA today's final rule. Those explanations proposed to require non-transient non- were proposed to be required in each communitywater systems to meet the public notice for failure to comply with

same requirements as community water any MCL. that the resource burden to the systems by broadening the definition of 

### C.Public Commentson the Proposal "community water systems." This category of public water systems EPA requested comments on all includes such systems as schools and aspects 

### of the November 13,1985,

. factories where the same consumers proposal and the April 17.1987,
may be exposed not only for part of the reproposal. A detailed summary of the

### No. 130 

## / Wednesday, July 8. 1987 

## / Rules and Regulations 

### 25695

FR 33992, September24,1986, for a full discussionon 

### WAS Guidelinesfor Carcinogenic Risk Assessment.) On November 13,1985,the Agency promulgated an RMCL for p-dcb asa Group 

### D substance, based on chronic toxicity data 

### from the studies available
atthat time.

After that notice was published, the Agency received the results of 

### a longterm study on p-dcb conductedby the NationalToxicology FVogram (NTP) (Ref. 6). The

### NTP studywas a chronic bioassay which used F344 rats and B6C3Fl mice. Tumors were found in both species of animals atincidences which were statistically significant. Therefore on April 17,1987EPA reproposed the 

### MCLG for p-dcb. The JPAproposed the MCLG consideringa classification of 

### BZ for p-dcb but acknowledged the controversy surrounding this classification and presented an alternative Group C classification.Public comments were solicited on whether p-dcb shouldbe classified as a B2 

### or C substance.The conclusions of these comments received

on this proposal differed even though they were using the same criteria in the guidelines; eight commenters would place p-dcb in group 

### C, two in Group 

### B2. The Agency recognizes that aswith
most chemicals, the evaluation of the carcinogenicity potential of p-dcb in humans is a difficult and somewhat controversial activity, in light of divergent interpretations made by the scientific community. Because it is
necessary for the Agency to make a judgment based on a reasonable weighing 

### of the evidencefrom the data
at hand, at this time pdcb is being classified in category C (possiblehuman carcinogen).

At issue in the controversyof the classification is whether there exists "sufficient" evidenceof carcinogenicity (Le., B2 classification)

### or whether there is only "limited" evidence of carcinogenicity (Le. Group C).

A Group B2 substance is definedby the following factors:

An increased incidence

### of malignant
tumors 

### or combined benign and malignant tumors in:

(a)Multiple species 

### or strains, (b) In multiple experiments (e.g.. with differentdose levels and routes of exposure)

### or

(c)To an unusual degree in a single experimentwith regards to a high incidence,unusual site 

### or type of tumor,



### or early age at onset.

A Group C is defined by the following factors: Having limited animalevidence of carcinogenicity in the absence 

### of human data in which:

(a) The studies involve a single animal species, strain 

### or experiment and do not meet criteria for sufficient evidence.

(b)The experimentsare restricted by inadequate dosage levels, inadequate duration of exposure, 

### or inadequate reporting, 

### or

(c)The studies show an increase in the incidence of benign 

### tumors only.

As pointed out in these Guidelines, this classificationis not meant to be appliedrigidly 

### or mechanically, but a balancedjudgment of the totality of the available evidenceneeds to be considered. 

### This weight of the evidence approach can increase the number of reasonable interpretations to the same data base.

DecisionProcess

Evaluating the increasedmale rat kidneytumors and liver tumors in male and female mice of the NTP 1986 bioassay,p-dcb might 

### be tentatively classified in Group B2 probable human carcinogen. However, when reviewing the total weight of evidenceat this juncture, pdcb could also be classified in Group C possible human carcinogen. Factorsrelevant to determining weight of evidenceinclude: 1) evidenceof carcinogenicity, 2) structurelactivity relationships, 3) genotoxicity test findings, and 4) results of appropriate pharmacokinetic and toxicological observations.

Because the carcinogenicity bioassays (discussedunderEvidence 

### of Carcinogenicity) do not provide unequivocal evidenceof carcinogenic potential for humans, 

### it is necessary to consider all factors 

### in determining the weight of evidence for p-dcb carcinogenicity.

(I)Evidence

### for Curcinogenicity. Evidence for the carcinogenicity of p-dcb is primarily limited to the NTP study of F344 rats add B6C3Fl mice. In this study, 

### rats and mice were exposed
to two doses of pdcbin 

### corn oil administeredvia gavage. The

### NTP concluded that there was clear evidence of carcinogenicityboth for male rats as shownby an increasedincidenceof renal tubular cell adenocarcinomasand for mice of both sexes as shownby increased incidencesof hepatocellular carcinomasand hepatocellular adenomas. No evidence

### of carcinogenicity was seen in femalerats.

The issue-ininterpreting the guidelines is to determine the relevance of both the male rat kidney and mouse liver tumors to human carcinogenesis.Inductionof male rat kidney tumors by several nongenotoxoc organic chemicalshas been linked to the presence of hyaline droplets composed of alpha-&-globulin, a protein which has not been detected in female rats, mice or humans. There is evidencefor the formationof hyaline droplets in male rats given pdcb orally. It has been asserted by several investigators and commenters, and supportedby substantial data, that alpha-2u-globulin is essential 

### for hyaline droplets in the male rat kidney. Presenceof hyaline droplets seen only in the male rat kidney, which was the target organ in the

### NTP bioassay. and lack of hyaline droplets in the femalerat kidney, which

was not a target organ, supports the hypothesisthat hyaline droplets formation may have limited significance for human exposure to p-dcb. The mechanism of carcinogenesisis not absolutely certain but the involvement of alpha-Zu-globulinis a probable and sound scientificexplanation that has been developedfrom a large body of mechanisticandpharmacokinetic studies on this chemical.

The significant increase in mortality indicatedthat the 

### MTD was exceeded for the high dose malerats.

Diminished toxicological significance might be ascribed to mouse liver 

### tumors, which are inducedby a number of chlorinated hydrocarbons. As with
tumors of the male rat kidney, theories have been proposed which argue that the mouse liver response is not relevant
to humans. Explanationsare still tentative and the possible relevanceto human carcinogenicity 

### is a current topic of debate.

Other bioassays have been performed which although having some shortcomings conh the negative results in the low dose

## NTP bioassay results. Alderly Part Wistar rats were exposed to multiple doses of p-dcb via inhalation for 76 weeks,followed by an additional 36 weeks of observation (Riley et al., 1980; described in Ref. 8). No increases in tumor incidence

### or type

were observed.Comparisonsof this study with the 

### NTP bioassay are made difficult because of the differences in the
route and duration of exposure. However, if 0.1 liter/minute was assumed asthe breathingrate for 500 gram rats exposed to p-dcb for five hours/day, five dayslweek for seventysix weeks, the estimated daily oral dose would be 178 mg/kg. This estimated dose is slightly higher than the low dose of 150mg/kg in male rats, which did not produce a significant increase in kidney tumors, asreported 

### from the 

### NTP study. While the shorter duration 

### of exposure may be responsible for diminished tumorigenicresponse, the variety of toxic effects (increase in liver, kidney, heart and lung weights, increase in urinaryprotein and coproporphyrin output) in the high dose group (500 ppm) indicate that the 

### MTD was approached.

Subchronicstudies have demonstrated evidence of liver and kidneytoxicity and a variety of other toxic effectsfrom pdcb exposureto animals either via gavage

### or inhalation (Hollingsworth, 1958,1958; described in Ref. 8).No evidence of carcinogenicity

was found, but the short duration of these studies (&monthduration) precludes detecting carcinogenic effects unless the latency would be unusually short and the compound were a potent carcinogen.



### No evidence of carcinogenicity in humans has been reported, which 

### is not unusual. Therefore, inadequate data are available to assess the weight of evidencefor carcinogenicity 

### from epidemiological/casestudies in humans.

Thus, consideringthe totality of evidence, the available bioassay data

are equivocal as

### a basis for extrapolating to humans and the epidemiological data are inadequate.

### In thejudgment of the Agency, a Group C classification 

### for p-dcb would be more appropriate than a B2 classification based upon the information currently available.

(2)StructumActivity. Compounds with similar chemicalstructures have been tested in long-term carcinogenicity bioassays, but no clear evidenceof carcinogenicity has been reported. Such structure-activity information can 

### be useful when evaluatingclosely related chemicals.

Two compounds with similar
structures to p-dcb [orthodichlorobenzene (o-dcb) and monochlorobenzene (mcb))have been tested in NTP bioassays. As with p-dcb, the compounds were administeredin

corn oil via gavage to F344 rats and B6C3K mice. Under test conditions, 

### odcb was not carcinogenic at doses of 60 and 120

### mg/kg administeredfor 103 weeks.

### For mcb, anincrease of neoplastic nodules of questionable statistical significance was found for high-dose male rats (120 mg/kg). 

### Both odcb and mcb have been classified as Group I): inadequate evidencefor carcinogenicity.

Metabolitesof p-DCB (2.5­ dichlorophenol and its hydroquinone) have not been tested for carcinogenicity. 2,4-Dichlorophenol was administeredin drinking water in a two-year bioassay in
rats 

### (Exon and Koller, 1985; described in Ref. 8)and found to produce n in tumors, but was cocarcin administered

### with e

positive findings. but they do from the overall weight of evi carcinogenicity in this case.

(3) Genotoxicity Tests. p-&b determinednot to be genotoxic variety 

### of short-termgenotoxici bioassays. Therefore, it is less 

## riq
that it could be carcinogenic 

### by a 

## 4 genotoxic mechanism. GenotoxidG often associated mechanistically carcinogenicity. Some non-genotd substances are carcinogenic by unknown mechanisms. 

# 1

p-Dcb is not mutagenic when ted SaImonelia typhimurium 

### or in the 

### J 

### WP2 system.Increased frequency back mutationwas observed on 

### th 

# 1

methionine requiring forms in the

## 6 Aspeqih nidulans,however 

### this? finding is not considered

### signifid

p-Dcb was not found to induce 

# 4

forward mutationsin mouse 

### lymph cells, sister chromatidexchangeie: Chinese hamster ovary 

### cells or 

### 4 unscheduledDNA synthesis in hum lymphocytes. Negative results wed obtained in cytogenicity studies Wn bone marrow cells and a dominant: lethal study in CD-1 mice followi$ exposureto p-dcb. 1

8 (4)Pharmacokineticand i ToxicologicaalObservations. ‘ Commentem also raised questions the relevance of the results of the bioassay to 

### exposure of humans to$ 

### DCB via 

### drinkwater. 

### Issuesinclude toxicological significance of the 

### ma administration(gavage vs. drinking water) and the vehicle used [corn 

## 4 drinking water). 

### n

With respect to both mode of administrationand vehicle, no data available specifically on pdcb, but bioassays on other chlorinated hydrocarbonshave shown that the pharmacokineticsof absorption/ distribution differ between compoa administeredin corn oil via gavage compared to drinking water administration. The issue that the c’ oil vehicle itself may affect hepatic metabolic capabilities and influenct susceptibility of the mouse to hepat
tumors has been a subject of controversy. 

### No. data are available specifically on p-dcb.

### - 

## / Rules 

### and Regulations 25697

Section 1412(b)(5) 

### of the Act defines "feasible" to mean "feasible with the

use of the best technology, treatment techniquesand other means which the Administratorfinds, after examination for efficacyunder field conditions and
not solely under laboratory conditions,

are available (taking cost into consideration)," Le., "BAT."

This provision represents a change from the provision prior to 1986,which required EPA tojudge feasibility on the basis of "best technologiesgenerally available" (I'BTGA"). The 1986 amendmentschanged BTGA to BAT and added section 1412(b](5), which reference dose (0.1mglkg/ specifies that the technology selected as x body weight day)(7og] BAT must be tested for efficacy under



### - = 3.75 %/I field conditions, not just under DWEL = daily water consumption Wday

drinking water equivalent level x relative source contribution

additional uncertainty factor



# - = 0.075 mg/l (75 pg/l)

the referencedose is calculated as:

no observable effect level
uncertaintyfactor Had p-dcb been assignedto Group ~2, the 95%upper-limit carcinogenic potency factor for humans,ql*, would be the basis for the quantitation. A "what if' calculation forp-dcb, using the ' draft ql* value is 2x10'2 (mg/kg/day)-l by the multistage model and male mouse liver tumor data indicated an upper-limit individual lifetime cancer risk 

### of 4x10-5 for a 70 

### kg human 

### L/water a day 

### for a lifetime

### (assumed

### to be 

## 7o years) exposureto drinkingwater containing 75pg/L.



### C.MCtSfor VOCs



### In this rule, EPA is promulgating MCLs for the eight VOCs asfollows:

I

### _.._." ...-"

._



### ....... Benzene.-...-

--.--I-.. 

### _.".. 0.005 vw

# -

......-..

I.-....- 0.002

I 

### .-- ...............-. .. Ch-bLlntetreCMoride



### ...

............ 0.005 12-DicMoroemsna

....

............ 

### ............ 0.005 TricMwoethylene

### .-..--



### ................................ 0.005
ene.-.--



### ............................. 

# ??a

0.007



### ......



### ".""....

.................

~ 

### .......... 0.075

1.1.1 -TricMaoemane



### .........................

~ . 

### ...._........ 0 2 I 

# -

As noted earlier, section 1412@)(4) of the Act requires EPA to set MCLs as close to the MCLGs asis feasible. laboratory conditions. The legislative history explains that CongreG removed the term "generally" to assure that MCLs "reflect the 

### full extent of current technology capability." 

### [S.Rep. No. 56, 99th 

## COW^ 1st sesS.1 at 6 (198511. Read together with the legislative history, EPAhas conchded that the term "best available technology" is a broader standard than "best technology generally available" and that this
standard allows EPA to 

### select a technologythat 

### is 

### not necessarily in widespread use, aslong as it has been field tested beyond the laboratory. In addition, EPA believes this change in the statutory requirement means that the technology selected need not necessarily have been field tested for each specific contaminant. Rather, EPA may project operating conditions for a specific contaminant using a field tested technology from laboratory or pilot systems data.

.

Based on the statutory directive for setting 

### MCLs, EPA derives the 

### MCLs from an assessment of a range of pertinent factors, including the availability and performance of BAT, the costs of these technologies for different size water systems, and the number ofwater systemsthat would have to install technologies. EPA also evaluates the availability of analytical methods and the reliability of analytical results aswell as the resulting health

### 256% Federal Register 

## / Vol. 52, 

### No. 130 Wednesday, July 8, 

### 1987 

## 1 Rules and Regulations

risks of various contaminant concentration reduction levels attainable by BAT. 

### For drinkingwater contaminants, the target reference risk
range for carcinogens is

## lo-‘ to and most regulatory actions in 

### a variety of EPA programs have generally fallen in this range using conservative models which are not likely tu underestimate the risk. Of course,MCLs could be set outside the range depending upon the feasibility of achieving a specific level.

1.Treatment Technologies

As explained in the November 1985 proposal, EPA examined a number of
treatment processes for their potential 

### to reduce the level of VOCs in driwater. These technologies are discussed in the document ‘Technologies and Costs 

### For The Removal of Volatile OrganicChemicalsFrom Potable Water Supplies.” (Reg. 2). (A draft 

### of this document was available at the time of the proposal. The final document 

### is available from the National Technical Information Service at the address listed in SectionVI of this notice.)



### in reviewing the different technologies available, EPA looked at the 

### following factors:Removal efficiency, degree of compatibility with the other water treatment processes, service life, and the ability to achieve compliancefor all the
water in a publicwater system.

Based 

### on these criteria, in the November 1985notice, EPA proposed granular activated carbon (GAC)and packed tower aeration (PTA)as “best” technologies forremoving VOCs from 

### drinking water. As described in that notice (50F’R 46914). these technologies have the followingcharacteristics: good removal efficiencies (90to 99 percent): compatibility with other types of water treatment processes: reasonable service life: and ability to achieve compliance for all the water in a public water system. In addition, these two technologies are commercially available and have been used successfully to

remove

### VOCs in ground water from both influents and effluents in many locations across the United States.

In the 1986 amendments to the Safe

, 

### Drinking Water Act, Congress specified in section 1412(b)[5)of the Act that: granular activated carbon is feasible for the control of synthetic organic chemicals, and
any technology. treatment technique, or other

means found to be the best available for the control of synthetic organic chemicals must be at least as effective in controlling synthetic organic chemicals as granular activated carbon.

For all the 

### VOCs except vinyl chloride, EPA has-identified GAC as technology that is effectivefor removing VOCs. PTA is equally effective. Therefore,these two technologies are “best” for these seven

### VOCs. PTA is

more effective 

### than GAC for vinyl chloride, asnoted below.

Vinyl chloridediffers from the other VOCs because it is a gas under typical temperature and pressure conditions. Therefore,vinyl chloride is most easily removed by PTA treatment. Because vinyl chlorideis a gas and a 

### known human carcinogen, no laboratory isotherms have been developed by EPA



### or reported in the literature. However,

one investigatorreported sporadic removal of vinyl chloride from ground
water in Florida using GAC 

### (Symons, 1978).This investigator also noted that vinyl chloride was the only one of a number 

### of related, low molecular weight VOCs to show such an erratic pattern. A

more recent, unpublished study 

### of ground water in Wisconsin @PA, 1987) showed less erratic removals at a higher empty bed contact time and lower raw water concentrations. It is difficult 

### to interpret either of these studies. Therefore, because PTA has been demonstrated to be extremely effective and GACmay, under some circumstances, exhibit poor 

### or erratic removal, EPA is not specifying GAC as “best” for the removal 

### of vinyl chloride. ITA, however, is “best” 

### for removal of this contaminant.



### Also, it shouldbe noted that the data used to determine removal efficiencies

were based 

### on performance for ground
water. EPA expects that GAC, applied
to surface water, would achieve lower performance efficienciesbecause of the higher levels of organic carbon found in surface water which cause more rapid depletion of the capacity 

### of the GAC (groundwaters typically have very low levels of background organic carbon) (SeeReference 2).



### In addition to GAC 

### or FTA, there are other technologies which may remove VOCs from drinking water, e.g., resins, powdered activated carbon. However, EPA, has concluded that these technologies are inferior to GAC and IJTA for various reasons, e.g., the technology is not commercially available 

### or the removals are lower and/or less consistent. For a further discussion 

### of other technologies EPA considered, and why they are not designated as “best,” see 

### WAS technology and cost document (Reference2).

2. costs



### As noted above, EPA is to set the MCL as close to the MCLG as (Reference 2).

treatment cost estimates are

.

“feasible,”which is defined as “feasible with the use of the best technology.



## . 

# . which the Administrator finds



## . 

# . is available (takingcosts into

### Federal Register 

### Val.

VOCs, see the November 1985 notice (50 

### FR 46911, November 13,3985).

For contaminantswith MCLGs set at

.anon-Zero level (substances in

'concentration in principle.cannot be achieved.

### In the MCLsettingprocess, therefore, EPA evaluates the feasibility of achieving levels asclose to zero as feasible. Based on the costs and the .availability/performance of treatment describedabove, EPA has concluded that 

### GAC and PTA are 

### BAT [exceptthat 

### -GAC is not BAT for vinyl chloride. since it is not the "best" technology).

To determine,whatlevel was feasible

as

### BAT,EPA examinedthe total 'compliance costs atvarious levels of ,dontamination(as well asthe individual compliance costs summarized above). 

### For all the contaminantswith MCLGs at

to install treatment at a total trichloroethylene, carbon tetrachloride. 1.2-dichloroethane. and benzene at a005 mgll.



### For vinyl chloride, EPA

### has set the MCL at 0.002

### mg/l.

### This lowerlevel reflects the treatment capability of PTA that would be used to remove vinyl chloride, and it is not expected to result in any increased cost over an 

### MU of 0.005 

### mg/L EPAbelieves that very few, if any, public water systems will need 

### to install treatment solely to control vinyl chloride. Because systems with vinyl chloride present at any level virtually always have one or more 

### of the other 

### VOCs covered by 

### this rule present at levels higher than the promulgated 

### MU for these 

### VOCs. these systemswill be treating their water to comply with the 

### MCLs applicable to those other 

### VOCs and the same treatment (FTA) will also

remove the vinyl chloride to 0.002 

### mg/l.



### PA estimates the total compliance
costs to meet the eight MCLs at $300 million (total present value costs) and $22.5 million (total annual costs) (See Ref. 3, "Economic Impact Analysis of Proposed Regulations"]. EPA estimates the annual cost per family to be $41 per year 

### fora small system, $12 per year for

a medium system, and $3 per year for a large system.

3. OtherFactors

The other factors EPA examined supportits

### MCL determinations. They

are explainedbelow.

AnalyticalMethods. The Agency also examinedthe analytical methods available for the measurementof volatile organicchemicalsin drinking
water and summarizedits findings in the November 1985 notice. Based on this review, the Agency has determinedthat analytical methods currently exist which can reliably measure

### VOCs in drinkingwater. In addition, EPA has concluded that the cost of sample analysis at intervals necessary to assure detection of 

### MCL violation is economically feasible for all public
water systems. Costs are estimated to be approximately$150 to $Zooper sample analysis. Further discussion of available analytical methodsis included in the section on compliance monitoring. The MDL is the minimum concentration of a substance that canbe measured and reported with 99 percent confidence that the true value is greater than zero. These MDLs are the result of
measurementsmade by a few of the
most experiencedlaboratories under non-routine 

### and controlled ideal research-type conditions.



### MDh and

### PQLs. The MDLis used by individual laboratories to determinethe laboratory-specificminimum detection capabilities. EPAhas gathered 

## I Rules and Remlations 256%

information indicating that laboratories in general are able 

### to achieve MDLs 

### of 0.m mgll 

### or lower with the available 

### VOC methods (Ref. 1). Specifically, under single-laboratory,ideal conditions. the method detection limits 

### (MDLs) of the eight 

### VOCs have been determinedto range 

### from 0.0002 to OD5 mg/l.

In the November 1985 proposal, FPA definedthe "practical quantitation level" 

### (PQL) asthe lowest level that can be reliably achievedwithin specified limits of precision and accuracy during routine laboratory operatingconditions. PQLB thus represent a level considered
to be achievable

### on a routine basis.The basis 

### for setting PQLs is.(l) quantitation, (2)precision and accuracy, (3) normal operations of a laboratory, and (4) the fundamentalneed (in the compliance monitoring program) to have a sufficient number of laboratories available to conduct the analyses.

The PQL is analogousto the limit 

### of quantitation (LOQ) 

### as definedby the American Chemical Society. Both the LOQ and the PQL define the concentrationof an analyte above which 

### is the region of quantitation and below which is the region 

### of less certain quantitation. The difference isthat where the PQL 

### is an inter-laboratory concept whiIe the LOQ is specific to an individual laboratory. The Agency developed the PQL concept to define a measurement concentrationthat is time and laboratory independentfor regulatory purposes. The 

### LOQ and MDk although useful to individual laboratories, do not provide a uniform
measurement concentrationthat could 

### be used 

### to set standards.

PQLs 

### for the 

### VOCs were determined based on the MDL and surrogate test data. In the past, EPA

### has estimated the PQL at five to ten times the MDL and, in the November 1985notice, EPA suggested setting PQLs at this general
range. In the notice �PA used the results of inter-laboratory studies to confirm this estimate. The PQLs based on these laboratory data are considered a "twostepremoved" surrogate for actual laboratory performance, first because they are estimatedfrom another
measurement (the MDL) and second, because they are derived 

### From laboratoryperformance under ideal circumstances. Therefore, they do not actually represent the results of normal laboratory procedures,but are a model of what normal proceduresmight achieve. Specifically:
(1)Laboratoriesreceive performance evaluation samplesin which a limited number of concentrationsare analyzed

### 25700 

### Federal Register 

## / Vol. 52, 

### No. 130 

## / Wednesday, July 8, 1987 

## / Rules and Regulations 

# -

%.. -3

and the samples do not have matrix interferences asmight actual samples:
(2)PQLs are based on EPA and State laboratory data which are consideredto be representative of thebest laboratories, but not all laboratories: and

(3) Samples are analyzed under controlled ideal testing conditions which
may not be representative of routine practice.



### For these reasons, the PQL represents

a relatively stringent target for routine performance. EPA expects that the PQLs in this rule will push laboratories to perform at a higher level than they would otherwise. In the range between the MDL and the PQL, quantitation of contaminantscan still be achieved, but
not necessarily with the same precision and accuracypossible atthe 

### PQL. As
measurements approach the MDL, there is much less confidence in quantitation. Thus, PQLs set a target performance level forlaboratories using a specified
set of precision and accuracy limitations. In this manner,PQLs provide consistencyin implementing a regulatoryprogram, in a practical way, where both quality control and quality

assuranee is critical.

Most,commenters agreed with the PQL concept; however, several stated that the PQLs shouldbe verified further through additional multi-laboratory studies. For instance, several
commenters were critical of the PQL for vinyl chloride, stating that the level should be based on multi-laboratory data as opposed to simply being set at a value of five times the 

### MDL. EPA agrees that the PQLs shouldbe further verified

as explainedin Reference 1,the Agency collected additional multi-laboratory data including data on vinyl chloride, and used these data to set the final PQLs.

One commenter felt that PQLs should be replaced with the LOQ concept as described above. EPA does not agree that the PQL should be set based upon the LOQ because the LOQ is dependent

on the precision attainable by a specific laboratory, which can vary from day to day aswell as among laboratories. Thus, the LOQ is not designed to assess the performanceof a large number of good laboratories: instead, it is laboratory-specific and therefore is not suitable for setting criteria for national standards.

Some commenters stated that the PQLs were set at too high a level and suggested 0.001 mg/l, while others believed that the PQLs were too �ow. A 

### PQL range from 0.02 to 0.04 mg/l for benzene was suggested by one commenter. EPA disagrees with the comments that the 

### PQLs were set at the wrong level; the levels were selected based on multilaboratory data which confiied the general rule of five to ten times the 

### MDL. Setting the PQLs athigher or lower levels would not be consistent with the data. EPA recognizes that many laboratories have reported data at levels less than the 

### PQL;however, the Agency does not considerthe data sufficient
upon which to base national standards consideringthe other data available. Again, PQLs providefor consistencyin data quality from a diverse group of laboratories across the country, and provideroutine performance goals that
many laboratories must strive to achieve.

As explained in Reference 1. the PQLs

are 0.005 mg/l for all the VOCs except vinyl chloride. EPA generallybased the PQLs upon a laboratory performance criterion of k20 percent 

### or 40percent, dependingon the concentration, for each individual VOC except for vinyl chloride which was 

## +apercent. This provides a relatively stringent performance target for laboratories but

one that has been demonstrated to be achievableby three-quarters of the "best" @PA and State)laboratories under evaluation conditions. It is expected that the remaining laboratories will need to upgrade their performance in order to meet this criterion. 

### For vinyl chloride, the PQL is 0.002mg/l (rounded from 0.0015 mg/l for the reasons discussed in Reference 1). The PQL of 0.002mgll recognizes that on the one hand the precision/ accuracy associated with measuring vinyl chloride is expected to be less than for the other VOCs; but that, on the other hand, vinyl chloride is a 

### knownhuman carcinogen of high potency and the risk posed by each unit of exposure could be higher than for the other VOCs. Because of this latter factor, EPA believes it is appropriate to accept slightly less precise data in order to seek to obtain

more stringent levels of control. Technical assistance to laboratories that wish to be certified to analyze vinyl chloride is available for EPA-EMSL in Cincinnati.

For each VOC, the PQL is equal to or less than the MCL. Therefore, laboratories will be able to reliably determinewhether systems are in compliance with the MCLs.

Health 

### Risks. PA examined the theoretical maximum health risks expected at various contaminantlevels.

. These health risks include non-cancer risks, aswell ascancer risks. The upperlimit unit 

### risk estimates from the animal 'data are derived from a linearized multistaged nonthreshold extrapolation model that is currently programed

## ai

GLOBAL 83. Justificationforits use is: presented in EPAs Guidelines for Carcinogenic 

### RISK Assessment.

### Wh&

## ,;
recognizing that alterna live statistical' modeling approaches exist (e.g., one& Weibull, log-probit and logit models,



### . and maximum likelihood estimates),

## a
range of risks describedby using any these modeling approacheshas little .; biological significance unless data caq be used to support the selection of one. model over another. 

### In the interest of:; consistencyof approach and of providing anupper bound estimate for the potential cancer risk, the Agency 

## :-, recommends the use of the linearized,.l multistage model. 

### EPA considersthis 

# :, model and resulting risk estimates to b

anupper-limit value in the sense that the true risk is unlikely 

### to be higher ani
may be lower. An established procedw does not yet exist for making "most likely" 

### or "test" estimates of risk wi& the range of uncertainty derived by 

### the
upper and lower limit values.

, . , 11

Table 2 presents samplerisk

. .$ estimates calculated at the 95 percent-: confidence limit using the multi-stage ; model for the five VOCs which are

I 

### . considered

### known or probablehuman: carcinogens. EPAs Carcinogen -,! Assessment Group (CAG) cakculated 

## I;
these numbersbased on the assumptior .oftwo liters 

### of water ingested dailypy

a lifetime of 70 years for a person



### .. weighing 70kilograms (kg). The Agenc] calculates these risk estimates so that I they are not likely to underestimatethe actual risks, and are conservatively 

## :.: used to evaluate "worse case" scenaric for the purpose of regulatory-impact analysis. ..:I

TABLE 2-AN EXAMPLE OF UPPER BOUND LIF

TIME CANCER RISK (10'6) ESTIMATES F( VOCS CATEGORIZED AS KNOWNOR PRO,?
BE HUMAN CARCINOGENS

'Risk &Is are best represented by one mnt &7 because ol lhe imprecise natured the I@ rodel eXaspP Ions.

"Ca~lation 

## ""8 pr- ncldyes.lf Preww nodules wenot actwed into the nsk assessmenr I estimaledriskallO~l;sO.OZmgll

. . . . . I :.'I

As mentioned above,

### for contaminantsin drinking watkr, the target reference risk range for carcinogens is 10 -I to 10 -.and the, 

### .,: MCLs EPA is promU1gati.q 

### in this no@

' generally fall 

### in this'range. EPA ' considers these to be safelevels and52, 

### No. 130 

## 1 Wednesday, 

### July 8, 1987

considersthe MCLs determined

ssary contaminationand to

ate that treats all of the water and through indoor air transport (e.g.. from showers 

### or dermal contact). 

### In addition, these devices 

### are generally not affordable by large metropolitanwater systems,which is one of the criteria for setting

### BAT.

In the November 1985 notice, the Agency discussedits proposal to not allowPWSs to use bottled water 

### for compliance 

### or to meet conditions of variances and exemptions. Public
commentspointed out that bottled water may, in a few cases, be the only available "treatment technique" for the the smallest systems. The Agency restated in its April 1987 notice that bottled water was not an acceptable

means of meeting the 

### M U requirements



### on a permanentbasis since it does not provide the same level of protection as central treatment (i.e., persons may choose not to drink bottled water) and bottled water might allow significant
exposureto water which does not meet the drinking water standard during showering and other applications. However, in that notice, EPA proposed that bottled water be allowed

as an interim measure to prevent an unreasonablerisk to health during the time between detection of 

### an Ma violation and achievement

### of compliance; it is emphasizedthat provision of bottled water during this interim period does not bring the PWS into compliance with the MCL; bottled
water does, however, provide an acceptable source of water to drink during the interim period. In a 

### future notice, EPA will further assess the advisability of allowing some NTNCWS and very small systems to use bottled water to meet the MCL requirements.

The majority of commenters agreed that POU/POE devices and bottled
water should not be consideredBAT, and that the NPDWR shouldnot allow their use for compliance with MCLs, due
to difficulties in controllinginstallation, maintenance,operation, repair, and potentisl human exposurevia untreated taps. However, other commenters stated that POU/POE devices and bottled
water should be consideredBAT 

### or allowed for compliance, as these technologies were often more costeffective for some small systems than central treatment.

In this final rule, 

### POE and POU devices are not designatedasBAT because: (1) 

### It is significantly more difficult to monitor the reliability of 

# .~ treatmentperformance and to control the operation

### of POE and POU devices in a manner comparableto central treatment; (2) these devices are generally not affordable by large metropolitan water systems; and (3)in 

## 1 Rules and Regulations 

### 257tU

the case of 

### POU devices. not all water is treated. 

### In addition, under 

### this rule, POU and bottled water are not considered acceptable means of compliance with MCLs. These devices do not treat all the
water in the home and could result in health 

### risks due to exposureto untreated water. Consequently, POU devices and bottled water are only considered acceptable for use asinterim

measures, e.g., as a condition of obtaining a variance or exemption, to avoidunreasonable risks to health before full compliance be be achieved. Under 

### this rule, however, POE devices

are acceptable means of compliance, because WE providesdrinking water that meets the standards throughout the home. 

### These devicesmay be costeffective for small systems or nontransient non-community water systems (forwhich these deviceswouM often be essentially the same ascentral treatment), although operational problems may be greater than for central treatmentin a community system.

The SDWArequires EPA to establish
necessary oonditions for use of
treatment that will assureprotection 

### of public health. Specifically,section 14Ol(I) 

### of theAct states that primary drinking water regulations are to contain "criteria and proceduresto

assure a supply of 

### drinking water which dependably complies with



# . 

# . . maximum contaminantlevels, including quality control and testing procedures to insure compliance with such levels and to insureproper operation and maintenanceof the system." Accordingly, 

### this rule imposes the following conditions on those systemsthat use POE for compliance:

(1) Centml Control. Thepublic water systemwill be responsible for operating and maintaining allparts of the
treatment system (i.e., the treatment device). Centralownershipis not necessary, as long as the public water systemmaintains control of the operation

### of the device. Centralcontrol is appropriate and necessary to ensure that the treatmentdeviceis kept in working order.

(2) EffectiveMonitoring.As monitoring the quality of a PWS drinking water is a central part of ensuring compliance with any NPDWR, the public water system must develop a plan and obtain State approvalfor a monitoring plan before it installs the POE devices. Because POE devices present a fundamentally different situation than central treatment, a unique monitoring plaq must be developed. This monitoring plan must

ensure that the POE devicesprovide

# I 25702 

### Federal Register 

## / Vol. 52, 

### No. 130 

## I Wednesday, July 8, 1987 

## / Rules and Regulations

health protection equivalent to centra1
water treatment. Equivalent means that the water would meet all Primary and SecondaryDrinking Water Standards and would 

### be of acceptable quality similar to water distributed by a well operated central treatment plant. In addition to the VOCs. monitoring must include physical measurementsand observations, such as total flow treated and the mechanicalconditionof the
treatment equipment.

(3) AppIication

### of Effkctive Techeology There are 

### no generally accepted standards for the design and construction of POE devices, and there

are a variety of POE designs available, Therefore, the Statemust require adequatecertification 

### of performance, field testing, and, if not includedin the certificationprocess, a rigorous engineering design review of each type of device. Certification can be done by the State 

### or by a third party acceptable
to the State. (4)

Maintenanceofthe MicrobiologicalSafety of the Water. The design and application of 

### POE devicesmust,considerthe tendency for increases in bacterial concentrationsin
water treated with activated carbon and

some other technologies. It may be
necessary to use frequent backwashing, post-contactor disinfection, and monitoring 

### to ensure that the microbiological safety of the water is
not compromised.EPA considers this condition necessary because disinfection typically is not provided after point-of-entry treatment asis normal is used in a central treatment plant. (5) Protection ofAN Consumers.Every building connected to a public water system must have a POE device installed, maintained, and adequately monitored If the buildingis sold, the rights and responsibilities of the utility
customer must be transferred to the new

owner with the title.

E.Analytical Methods and Compliance MonitoringRequirements \

1. Analytical Methods

In the November 1985notice, the Agency proposed the use of three analytical methods that it considered economically and technologically feasible for monitoring compliance with the VOC MCLs. These methodswere: (1)EPA Method 502.1, “Volatile HalogenatedOrganic Compounds in Water by Purge and Trap Ga$ Chromatography

## .“

(2)EPA Method 503.1, “Volatile Aromatic and Unsaturated Organic Compounds in Water by Purge and Trap Gas Chromatography.” (3)EPA Method 524.1, “Volatile Organic Compounds in Water by Puqe and Trap Gas ChromatographylMass Spectrometry.”

Capillaw Column Techniques. Same
commenters recommended the use of capillary column techniques for VOC analyses. The Agency evaluated capillary column methodology and agreed that they are available. Some
commenters alsorecommended the use of detectors in series to analyze purgeable halocarbons and aromatics simultaneously. The Agency agrees and has developed Method 502.2, which provides for the use of detectors in series, and proposed capillary column analytical methods at 52 FR 12879 (April 17,1987). This final rule includes the capillary column methods as approved analytical methods:

(I]Method 524.2, “Volatile Organic Compounds in Water by Purge and Trap Capillary Column Gas Chromatography/ Mass Spectrometry.”



## 4) Method 502.2, “Volatile Organic Compounds in Water by Purge and Trap Gas Chromatography with Photoionization and Electrolytic Conductors in Series.”

Disapproval of the 6wSeries Methods. In addition, on May 27,1986 (52FR 19076),EPA requested comment

on whether to approvethe 600 series methods (i.e., EPAs analytical methods for detectingvolatile synthetic organic compounds in wastewater, Methods 601. 602,and 624in 40 CFR Part 136) for compliance monitoring since a number of comments to the November 1985 notice suggested they be approved as well.

EPA has evaluated the comments and determinedthat the 600 series methods

are technically very similar to the 500 series methods (e.g., the analytes covered, and the analytical columns, detectors, and chromatographic conditions are the same). However,FPA has determinedthat the methods are not interchangeablefor variousreasons. First, their analytical objectives are different. The 500 series methods emphasizedetectability at low levels while the 600 series methods do not focus 

### on measurements near the MCLs (the samplevolume is 5 ml in Method 624 versus 25 ml in Method 524.1). Second, the specific quality control requirementsthat must be met for the
500 series and the 600 series methods

are different. The performance criteria specified in the 500 series methods are

more stringent than those in the 600 series methods. For example,the 500 series methods include a requirement that laboratories analyze quality control standards within 60 and 140percent of the expected value, while the methods are not designedto maximize

. detectability at low levels and do not have as stringent performancecriteria,

, as do the 500 series methods.

1983 (48

### FR 45502), and further discuss in the November 13,1985, VOCEMCL :- proposal (50FR 46902). Tier 

### II

. contaminants are thosewhich 

### are of

. sufficient concern to.warrantnationa1 regulation (i.e.,.MCLs Dr treatment

.... technique requirements) but which..

occur with limited frequency, therefore: justifying flexible national minimum 1 .’ -monitoring requirementsto be applied by the State. :.:. ,. . , 

### :

- .

.. .

# s

he

600

!?

ze t ia,

ants

3. blic ing ?ncy ier

issed 

### :L

f .a1

Ore.

1 ed

e

(50 )rthe

S

”­

. .

ter

3e

ry -face
nts

ine mple

:rfor

ems; to

s for

vere
3W

### 1, Id be

:r

nduc

;ed

the 

### Federal Register 

## 1 Vol. 512,

### No. 130 

## I Wednesday, 

### July 8, 1987

samplingfor systems with wells that only operate a few months a year. Other
commenters recommended that the vulnerability assessment be included as part of the sanitary survey which is conducted every three years under the



### . current TWDWR 

### .forcolifwp, rather than annually. Gommenters supported the provisions for “grandfathering” previous data in lieu of new data for the initial round of monitoring.

In this final regulation, EPA has retained the majority of the monitoring requirements described in the preferred option (Option 2). In the final regulation, EPA is requiring that all community
water systems and NTNCWs conduct an initial 

### round of monitoringto determine the extent of contamination of water supplies. All size systems must monitor

as the occurrence data collectedby EPA indicate that systems of all sizes have detected 

### VOCs atrelatively high concentrations, sometimes without apparent sources of contamination.In general, the likelihood of contamination increases with population, since areas of large commercial 

### or industrial activity

are often located in large population
centers. The Ground Water Supply Survey of 1982 (Ref. 7) found that 16 percent of the smaller systems (<10,0oo people) and 28percent of the larger systems (>lO,OOO people)had detectable VOCs



# .EPA believes that phasing in the monitoringrequirements by system size is reasonable because of the greater vulnerability of the large systems and because these systems can

more easily handle the monitoring costs associated with this regulation. In addition, phasing in the requirements

over a four-yearperiod will allow the analytical laboratories to developthe capability to handle the additional samples. This is consistent with previous regulatoryactions implementing the Safe Drinking Water Act (eg., trihalomethanes).

EPA has modified the sampling locations for surface water systems such that samples can be taken after
treatment from entry points to the distribution system taps that are representative of each source.

EPA investigated the feasibility of compositing samples for 

### VOC analyses in an effort to reduce the monitoring
costs. Samplecompositing could then be used as a screening test to determine whether samples from multiple sampling sites may be contaminated by VOCs. EPA investigated compositesof 5 different samples since a concentration in the original sample above the PQL (and the MCL for some VOCs) should still be detectable but not quantifiable in

a composite sample resulting from such dilution, for example, if one of the five 

### } Rules and Regulations 

### 25703

samples were contaminated at 0.005 mg/

### 1and the other four were zero. Reanalysis of each sample would be required if 

### VOCs were detected in the composite sample. The experiments conducted by EPA were done to determine whether sample-compositing would 

### work for the VOCs (i.e., whether VOC losses could be kept to a minimum), and 

### to determine the technique most appropriate to minimize VOC losses.

The experiments conducted involved the preparation of composite samples for GC and GC/MS analyses.The procedures investigated for each type of analysis were different because of the differencein sample size (5mlsample purged for GC analyses: 25-ml sample for GC-MS analyses). The compositing technique that worked best 

### for GC analyses involved the addition of five 5­ ml samples to a 2Sml glass syringe and, after mixing, drawing out a 5-ml aliquot for analysis. The mixing should be done with the sample cooled at 4”C to minimize VOC losses. Data collected for five replicate samples demonstrated excellent recovery for all compounds (9.5-100 percent) with good precision, generally 33 percent relative standard deviation. The recommended compositingtechniquefor GC/MS analyses involves the injection of 5 ml of each sample directly into the purge

- device. For most components, recoveries

were greater than 85 percent with good precision, generally between 3-5 percent relative standard deviation (Reference 1).

Based on this information, procedures for compositing samples are included in the regulations. Several points 

### are briefly addressed below. Samples are to be collected from each source and shipped to the laboratory where they will be composited.Compositingis not done in the field. Public water systems and States that collect samples must be

aware that there are some potential problems that should be kept in mind when they composite samples.It is desirable that sampling schedules be arranged in a manner that provides for collection of all samples to be composited the same day. Sample preparation and analysis must take place within the maximum holding time of 14 days. The samples collected are shipped to the laboratory where the analyst will prepare a composite sample from a series of discrete samples. This additional sample preparation step provides more opportunityfor the introduction of recordkeepingerrors so additional care must be taken. EPA recommends that all samples be collected in duplicate to provide an

### 25704 

### Federal Register 

### I Vol. 52. 

### No. 130 

### 1 Wednesdav. Tulv 8. 1987

additional sample in case VOCs are (2)The repeat compliance monitoring detected in the composite sample.This requirementsfor those systemsthat the would avoid the need to resample at State determinesare vulnerablebut in each sample siteto determinewhich which no VOCswere found in the initial site(s) may be contaminated.If VOCs sample,are based upon system size [see

are detected in the composite sample, Table 4). the original samples cannot be (3) 

### For systemsfinding two-carbon reanalyzed because of head space VOCs, vinyl chloride analysis is problems created when the 

### first aliquot required. If vinyl chloride is not detected

was taken. Reanalysismust be in the initial sampleStatescan reduce conductedfor each of the duplicate monitoring frequencies to once every samples,provided the maximum storage three years for vinyl chloride. time 

### of 14dayshas not been exceeded. AS 

### for comments recommending that Resampling must be doneimmediately EPA reduce samplingfor systemswith where one 

### or more VOCs are detected if wells that only operate a fewmonths a
no duplicates are available. year, the Agency believes that any such

The greatest limitation of compositing reduction 

### is appropriate. Under 

### this final samplesfrom different sourcesis that rule monitoring is required

### for all wells, the analytical results will not actually including backup wells, only when they provide a measurement 

### of what is 

### in the are being used. 

### For example,

### four water if the composite sampleturns out quarterly sampleswould not be required to be negative. It is possible that some for wells that are only used for say two VOCs may 

### be present at trace levels monthsper year; however, a sample and 

### will not be detected in a composite each quarter that the wells operate sample. Therefore, sample-compositing would be needed. is not thepreferred approachbut one The Agency agrees with the that can be used when monitoring costs recommendation that the State make a add a significant economic burden,with vulnerabilityassessment once every recognition of its limitations. three yearsrather than every year as

Confirmation samplesofpositive proposed. 

### In addition, EPAbelieves that results can be required by the State: the State shouldmake a vulnerability results of confirmation samplesmust be assessment (~500 connections)every included in the quarterly average along five years only. These changes are with the initial sample. States,however, reasonable because itis unlikely that have discretion to delete obvious significant undetected changes would analytical 

### errors in the initial or occurin the vulnerability 

### of a system confirmation samples. 

### in addition, sufficient to result 

### in sufficient VOC Stateshave discretion to require contaminationwithin 

### a one- to two-year additional monitoring samples: results 

### of time period. Thefinal rule reflects these all samplesmust be included in each changes. respective quarterly average (exceptas 

### EPA alsoproposedthe following noted above for obvious errors). method for determiningcompliance:

EPAmodified some of the monitoring (1) All quarterly compliance samples requirements it proposed in the would be collected un the same day and November 1985noticeto address the analyzed according toprocedures

concern of many commenters regarding promulgated in-this rule. monitoring costs. These changes are (21 Compliance with the 

### MCL would summarizedBelow and further be computed by 

### running arithmetical discussed in the Methods and average of the past four quarterly Monitoring document (Ref. 1). samples.

(1)The number of samplesrequired (3) Compliance would be determined for groundand surface water systems for each sampling location; if water at has been reduced from the number that location was above the MCL, the proposed. The rule allows composite entire systemwould be deemedout 

### of samples of multiple sampling sites [up 

### to compliance and public notice would be five samples),resulting in lower costs. sent to all customers servedby the Whenmonitoringcosts would create an systemunless there was no inter-mixing unacceptable financial burden,States of sourcewaters in distribution. that conduct the monitoring themselves EPAreceived a number of comments

can composite samplesfrom different on the proposedmethod of determining systems. This may be particularly compliance. Many commenters beneficial formonitoring non-transient supported the methods, while other non-community water systems. 

### As commenters believed that only that proposed, under the final rule, if VOCs portion of the system exceeding the

are detected in a composite sample, MCL shouldbe consideredout of follow-up analysis is required for each compliance and that public notification

source (see discussion of composite shouldbe limited to the affected samples). consumers. EPAbelieves that it is often 

## 1 Rules and Regulations

not possible to determinethe specific

have a clearly definable distribution systemfrom a source 

### wifhno interconnections to any other source. TO accommodatethese different situations, EPA is .promulgating

### the requirements

. . for determining compliance and public notification asproposed, except that the State may determinethat only one segment, 

### is., the affected part of a public water system,is out -of compliance and :hit publicnotification
to that one segment

provision. Sincethe 1986Amendments
to the 

### SDWA allow use of data for unregulated contaminantsback to January 1,9983,'EPAfeels it appropriat
to allow States discretion to alsouse

classified.as "vulnerable" and the 

### fin

sample)if the compositesreflect7 

## / Rules and Regulations 2m5

tetrachloroethylene, cis-1,zdichloroethylene, 

### or trans-l,Zdichloroethylene). (6)All systemsto which the

(7) Theserequirementsare

. . summarized in the table below: . , 

### I? Labomtory Approval



### EPA’s existing rules in 40 CFR 141.28 require that analyses for compliance monitoring purposesbe conducted only by State-approvedlaboratories. Laboratorieswishing to obtain approval for conducting

### VOC analyses must successfullyanalyze performance evaluation sampleswithin the limits established by EPA and meet other requirements. The acceptance limits for laboratory approval are derived from the performance evaluation study data, Le., the Water Supply Study series.

EPA requested comment on the use of

a “plus 

### or minus percent of true value” approach for settingperformance criteria 

### (Le., acceptancelimits).Most
commenters supported the use of a “plus



### or minus percent” approach to derive acceptancelimits over generatingthem from study statistics based upon 95 percent confidence limits. Some
commenters believed, however, that the specific acceptancelimits proposed

were too strict and there would be an insufficient number of laboratories available that could meet such standards. EPA disagrees with this
comment because the most recent water supplyperformance evaluationstudy showed that about 85 percent of all data submittedto FPA and Statelaboratories and about 70 percent of the other participating laboratories were within the proposed acceptance limits. These results compare favorablywith other regulated contaminantswhere, even after years ofexperience, only 80-85 percent of all the data submittedare within the acceptancelimits for each study. 

### A specific example is the trihalomethanes,where about 85 percent of the data submittedby EPA and State laboratories and about 75 percent of the data submittedby other participating laboratories are within the established limits. The actual percentage varies somewhatfrom study to study.

The acceptancelimits were proposed
to be +40 percent of the true value for concentrationsless than 0.010 mg/l, and 220 percent of the true value for concentrations of 0.010 mg/l or above 

### for all ofthe 

### VOCs except vinyl chloride. More recently, data from Water Supply Study No. 17,at 51 FR
19077 (May 27,1986)indicate that most of the better laboratories tested can successfully analyze performance evaluationwithin the proposed acceptancelimits. EPA considered lowering the acceptance limits for the

seven

### VOCs to 220 percent (excluding vinyl chloride). However, very few laboratories would be able to perform within these limits for all seven of the TABU 3.-&HEDULE OF REPEAT MON.ITORING REOUIREMENTS

the discretion to: system is out of compliance, public notification of the system’s customersis

# a

4

.:

## 'I 25708 

### Federal 

# Register Vel.

'-



### VOCs. Only 

### three outnf&ghtm~

. I laboratories wereable to aralyze

### six
out 

### of seven

### VOCB withii ihese 

### limits 

### in Water Supply Study %Y.Therefore. in the ha1 de.

### the acce-ptancelevels are S Opercent 

### of-the true value 

### �or concentrations 

### of o.010mgll 

### or 

### above,

, and S percent of $he

### We value 

### �or concentrations

### below ~.oiO 

### mg/l for

seven VOCs Itrichloroethylene, carbon tetrachloride, 21.1-trichloroethane. 1,~­ dicbroethane, benzene. 

### tidichloroefhylene, 

### andp dichlorobenzene).



### For vinyl chloride,

### the&al acceptancebits arebased initially 

### on rt40percent 

### of the hue value at

### all levels. 

### This is3ecause the available data support acceptance 

### limits of A40 percent 

### and 

### donot support acceptance limits-of

## +apercent

### .�or&is compound. EPA may modify fhe laboratory performance requirements

### for

### all 

### VOCs

asnew informationbecomes available.

Even the bestJaboratories may not

### be able toanalpeall

### he VOCswithin the acceptancelimits 100percent of 

### the time. Random errors are likely40 

### occur in any.large 

### data generation activity. 

### P A has evaluated data fromrecent performanceevaiuation studies to determinehow many analHes EPAand State laboratories were able to analyze within the acceptance limits. The number ofanalyteswithin the acceptance limits varies from laboratory
to 1aboratory.XPA evaluated data 

### from Water Supply Study #l7 

### forEPA and State laboratories that analyzed

### for all eight VOCs. The data indicate that 35
out 

### of 18 laboratories 

### (or 83percent of the laboratories] were able to analyze at least 8 out of 7

### VOCs (excluding vinyl chloride)af concentrations 

### of 0.004 mg/l



### or abovewithin-the acceptance hits, while only 7 

### of these laboratories 

### (or 39 percent

### of the laboratories) were able to analyze all7 

### VOCs. For very low levels [<O.W 

### mg/l) greater failure rates would result. 

### Whenthe highest concentration

### of pdichlorobenzene (0.776mg/l)was not considered, 15

I laboratories were still able to analyze at least 6out of 7 VOCs within the acceptance limits, while the number of laboratories that were ableto analyze all 7 VOCs increased to 12 

### (or87percent 

### of the laboratories]. 

### For vinyl chloride only 8out of 18 laboratories (or44 percent of the laboratories) were able to analyze all three levels within the f40 percent acceptance limits. When the lowest concentration (O.Ool5 

### =/I) was not considered, the number of laboratories within the acceptance limits increased to 13out of 18 [or72 percent of the laboratories). 

### NO. 31981 

# = = E

S3FJAdso 

### evaluated.pretiminaxydata 

### fromWatexSttpplyStudy i#;20

### to determinewhether 

### thisshady 

### supports the results from the WaterSuppiyStudy a7. Xkvosamples

### were affered 

### in@ studyto

### hse-laboratories wishing20 obtiiinconditiondappmvd 

### for'voCa One 

### sample oontainedfie 

### @hfVocS 

### for WMchMCLs

### are Miletin

### this notice. 

### The second 

### sample.contirined4 of the 8VOCs-plusstherSectiun1445 unregulatedVOCs.Excluding

### lvinyl chloride, there were a total of 1%
responses 

### forthe 7VOCs 

### from&e first sample and9 

### from the 

### .second sample). 

### The teeults aresummarized 

### in Table 4 fora

### total dsrlEPA and State

11 outd 11,­ 10 artd 11,. 9 art of 11 

### ..---..........

I 

### ..---­ 8 art ol 11 82 <a out of 11 

### ..-- 18

Taking 

### the data from the first sample for the seven

### VOCs, 36 out of 44 laboratories 

### {or 82percentof the laboratories) were able to analyze at least 6 out of 7

### VOCs within the acceptance limits, while only 22 out of 44 

### (or 50 percent of the laboratories]

were able toanalyze all seven YOCs. Theseresults are similar to the 

### results obtained in Water Supply Study#17 

### �or the 7 VOCs.

Twenty-nine out of the 

### 44 laboratories 

### (or 66 percent of the laboratories) were able to analyze vinyl chloride within the +40 percent 

### limits. These results are similar to the results obtained in Water Supply Study #17 when 

### the lowest concentration (0.0015 

### w/1) was not considered.

Based on the results obtained in Water Supply Study#17 [which are supportedby preliminary results from Water Supply Study#20), EPA concluded that it is reasonable to expect that laboratories meet the acceptance limits in 

### 0 141.24(g)[11)for at least 6 out of 7 of 

### the VOCs to receive conditional approval. Therefore, the Agency will provide conditional approval of VOC analysis to laboratories that meet the following requirements:

(I) Use approved analytical methods

as specified in 

### 80 141.24(g)(10)and 141,40(g);

(2) Are approved for T�-IMs analysis: and laboratories.

.-

.

1..

Variances

treatment techniques,-or

### other means which EPA finds are available (taking
cost into consideration); 

### .in

### this notice

referred 

### to collectively as.BAT. Furthermore;before a Statemay g variance, it must find thatthevari will not 

### result in 

### anunreasonable health, Thelevel representing unreasonable risk to health 

### for each

proposal addwssingthe next 40 contaminantsrequired to

### be regulated under the SDWA.byJune1988.The proposalis scheduledfor the Fall of 1987. 

### In general, &e unreasonable 

### risk
to health level would reflect acute and subchronic.toxicityfor shorter-term
exposuresand high carcinogenicrisks (ascalculated 

### using the linearized mul stage model in accordance with the Agency's risk assessment guidelines] long-term exposures.

. .

Under Section 1413(a)(4).States that choose to issue variancesmust..do SOremoval of para-dichlorobenzeneby $200per year to remove li2­

.. . -

CAssuming99 percent removal from 0.5 mg/l to 0.005 mgl11

1 PTA- GAC

Benze'ne



## ....................................... 

## "....-. 56,O00 1,ooO 180 13,000 5,500 153 l,l,l-TCA 

## ...........................................-... 50,OOO

. 700

. 156 13,000 3,500 110 p-BCB



## ....................................... 

## ......-

......: 63,OW 1,300

. 204 13,000 1,700 72

to 75,000 person (12 mgd) category. Thus, aeration treatment offera significanteconomies of scale, e.g., with Both pilot- and full-scale data that packed tower aeration respect to 1,2-&&loroethane removal, and granular activated =*On 

### are asplant size increases by a factor of

ese three (0.1313 mgd to 0.037mgd), the cost capab1e Of 90-99percent Or Seater
decreases 

### by a factor of two (202 to removals of the VOCs [exceptthat GAC gallons).,Inaddition, costs is 

### not 

### as effectiveas pTA for sol$/l,OOO chloride).

### In light of this removal

or dichlorobenzene, carbon usage rates are vary the BAT standard for small based on projection of pilot column systems. data. Neither adequate adsorption Requin?dExaminationand



### r isotherms nor coIumn data were Installation 

### ofAlternate Treatment available to project carbon usage rates Technologies.Under section 1415 of the Act, a State may grant variances from a25708 

### Federal Register 

### J Vol. 52, 

### No. 130 

### Wednesda

NPDWR if certain conditionsare met. that the State considers necessary. These conditions,described more fully These provisions 

### are aimed atbringing below, include: (1)

### An inability to meet the systeminto Compliance with the the MCLs despite the installation of the MCL as soon aspracticable. The best available technology; (21 a finding following pointsneed tobe taken into that the variance will not result in an consideration:

- unreasonable risk; (3) imposition of a (1)The schedule

### of compliance which complianceschedule; (4) implementation accompaniesa variance mayrequire of such additiond controlmeasures as that the systemexamine other treatment the Statemay require: and (5)public notice of the proposed variance and opportunity for a hearing.

To receivea variance, 

### a 

### PWS would be requiredto install BAT fmt even if the BAT was not anticipated to achieve the MCL; the objective would be to reduce the level of contaminants as much ascould beachieved by those technologies. The only exceptionto this requirement is that 

### if a system were to demonstratethat the best available technology only achieved de

### minimis reductionof the contaminant(s) of
concern, the systemwould not have to install that technology.’However, asa condition 

### of receiving a variance without installing MT,&e Statecould require comprehensive engineering studies of other technologies and if any

were technically feasible, it could require me

### of those technologies to

### be installed.

EPAhas identified three additional
treatmentmethods that thestatemay require the PWS to investigate 

### and, if feasible, to install as a conditionof obtaining a variance. These 

### are: (I) Removal using other aeration techniques, such asmultiple tray aeration, spray aeration, cascade aeration, diffused aeration, 

### or mechnical aeration; (2) removal using powdered activated carbon adsorption; and (3) use of an alternative source of water.

EPA discourages systemsfromusing

an alternativesource of water which has noVOC contaminationbut may be contaminatedwith other substances. Specifically, EPA discouragessystems which find lowlevels 

### of VOCs in &eir ground water source, which is otherwise of good quality, from switchingto a surfacewater source where the risk from disinfectionby-products(e.g., trihalomethanes]might be greater than from the 

### VOCs. In such 

### a case, where alternative sources pose

### a greater risk than the VOCcontaminated supply. 

### the
water supplier shouldhat the original
water.

Subsections 1415(a)(l](A)(i) and (ii) of the SDWA require the State .to prescribe

a schedule

### for compliance atthe same time that it issues a variance. The schedulemust include: (1)Incrementsof
progress toward compliance: and (2) an implementation plan 

### of such control

measures and application of other
treatment techniques

### or technologies methods (ea., various aeration technologies, powdered activated carbon, 

### or alternate sources of water) to determinetheir availabiiity, ieasibility,
costs. and effectiveness.

12) Such an examinationmay include engineering studies and pilot projects, for potentially applicable technologies,
to determinewhat reductionin VOC levels could be achievedby the
treatment method.EPA will Drovide guidanceon examining tech;lologies for compliance schedules.

(3) Systems

### or the State always.have the option ofproposing studies of other methods.

14) The State can decide whether 

### any 

### of the possible teatment methodswould achievereductionsin 

### VOC levels justifying use of that particular method.


### In such cases, the Statemay require, as part of the complianceschedule, installation and use of 

### such methods by the system.

Useof POLIDevices and3ottled 

### Water.As described above, under section 1415(a](l)(A)(ii).the State is to prescribe a schedulefor implementation of any additional control measures it may require. The Statemay require the

use 

### of 

### POU devices, bottled water, 

### or other mitigating measures as

### an “additional controlmeasure” 

### during the period of a variance, asa conditionof receiving the variance,

### if an unreasonable

### risk to health exists.



### Inprescribing the use

### of

### POU devices, the State would be required to impose the same conditions 

### as outlined 

### in sectionllI.A.1 

### �orapproval of 

### POE devices. 

### If a PWS distributes bottled
water as a control measure. the PWS
must ensure that the following conditionsare satisfied:

(l)(a”J The bottled water 

### is subject to a monitoring program thatprovides adequate assurances that the water meets all MCLs.The public water systemmust monitor the bottled water for

### VOCs the first quarter thatit supplies water to the public. and annuallythereafter. Results of the monitoring program shall beprovided to the State annually, 

### or

(b) The public water system must receive a certificationfrom the bottled
water company that (i) the bottled water suppliedhas been taken from an “approved source” as definedin 21 CFR 129.3(a): [ii) the bottled water company minimum standards for protection of publichealth.

2.Exemptions

### Federal Register 

## / Vol. 52, 

### No. 130 

## / Wednesday, July 8, 1987 

## / Rules and Regulations 2570

~~ ~~ ~~~~

a substantial number of instances,

PublicNotification persons served by it of (1)myviolation of any MCL, treatment technique requirement, 

### or testing provision prescribedby an NPDWR; (2)failure to comply with any monitoringrequirement under section 1445(a)of the Act; (3) existence of a variance 

### or exemption: and (4) failure to comply with the requirementsof a scheduleprescribed pursuant to a variance or exemption. The 1986amendmentsrequire that, within 15 months of enactment,EPA amend its current public notification regulations 

### to provide for different types and frequencies 

### of notice based on the differences between violations which

are intermittent 

### or infrequent and violations which are continuous

### or frequent, taking into accountthe seriousness of any potential adverse health effects which may be involved.

EPA proposedregulationsto revise the public notification requirementson April 6,1987 (52 FR 10972).The regulations proposed that public notices for 

### MCL and treatment technique violations [“Tier 1violations”) contain mandatoryhealth effects language specifying concisely and in nontechnical terms what adversehealth effects may occur as a result 

### of the violation. States and water utilities would remain free to add additional information to each notice, as deemed appropriate for specific situations. The April 1987notice proposed specific health effects language for the eight VOCs which are subject to today’s ruiemaking. The April 1987notice also proposed that a 

### CWS with Tier 1 violations must notify the public

### by newspaper,mail delivery of notice and
press release (for acuteviolations) is required. The proposal states that public
water systems which 

### fail to comply with any monitoring or testing requirements, which are granted variances or exemptions, 

### or which fail to comply with the requirementsof a variance or exemption schedule,would be required
to give newspaper notice, with additional notice at State discretion. The PWS is allowedto post notice under certain conditions for Tier 1 and Tier 2 violations. The Agency expects to promulgate final public 

### notification regulations in September1987.

I.ReportingRequirements

The current regulations, 40 

### CFR 141.31, require public water systems to report monitoring data to Stateswithin specified time periods. EPA did not propose any changes in these requirementsfor the 

### VOCs.No comments were received on this issue. Thus, EPA will require the same reporting requirementsfor the 

### VOCs as required under the current regulations for 

### other contaminants.

The reporting requirementsfor result of the monitoring for unregulated contaminantsIdescribed below) apply
to both the community water systems 

### (CWS) and the NTNCWS.Each CWSo NTNCWS must submit the results of 

### th~ monitoring within thirty days of receipt from the certified laboratory. These results are to be submittedto the State. In addition, the State or public water system must submit the following information to EPA for every sample: (1 Results of all the analytical methods, including negatives: (2) name and address of the system that suppliedthe sample: (3)contaminantsfor which the analyses were perform& (4) analytical method(s) used (5) date 

### of sample; and (6) date of analysis.



### J. Total VolatileSynthetic 

### Organic Chemicals (rvocl

In the June 12, 

### IW, proposal for MCLGs for the VOCs, EPA requested public comments on setting an

### MCLG and 

### MCL for total volatile organic chemicals toprovide additional protection from simultaneousexposure to multiple 

### VOCs. following analysis oi public comments and available scientific information, EPA determined that an

### MCLG and

### MCL would not be appropriate atthis time. This conclusior

was discussed in theNowember 1985 notice.



### K.

### Monitorin..for 

### Unregulated Contaminants

Section 1445(a)[l)of the Act requires 

### EPA to promulgate regulations 

### by December 19.1987, which require public
water systemsto conducta monitoring
program for unregulated contaminants. Each systemmust monitor at least once every five years for unregulated contaminantsunless �?PArequires more frequentmonitoring. This data will assist EPA in determining whether regulations for these contaminants are necessary, and if so, what levels might be appropriate.

EPA proposed monitoring requirements for 51 unregulated contaminantsin the November 1985 notice. The Agency also requested
comment ona method developedfor thc analysis of 1.2-dibromoethane 

### (EDB) and 12-dibrorno-3-chloropropane (DBCP)at low levels. These two compounds are includedamong the substances that PWSs must monitor under Section 1445, as discussedbelow. This method is entitled “Method 504­ 1.2-Dibromoethane (EDB) and 12- Dibromo-3-chloropropane in Water by Microextraction and GasChromatography." EPA received no comments on Method 504. The Agency believes that this method is adequate to determine concentrations of EDB and DBCP. Therefore, this method is included in this rule as the monitoring method for these 

### two contaminants. Several commenters pointed out that analysis of 10to 15 other compounds on the list of 51was more difficult than analysis of the other compounds, resulting in higher costs. In addition, they observed that the likelihood of these substancesbeing present is much less than for other VOCs. EPA agrees with these comments and thus is promulgating monitoring regulations which separate the unregulated contaminants into three lists 

### as follows:

List 1:Monitoring required for all CWS and NTNCWSs. Compounds can be readily analyzed.

List 2: Monitoring required only for systems vulnerable to contamination by these compounds. Compoundshave limited localized occurrence potential and require some specialized handling.

List 3: The State decides which systems would have to analyze for these Contaminants, which includes compounds that donot elute within reasonable retention time using packed column methods 

### or are difficult to analyze because of high volatility 

### or instability, and are much less likely 

### to be present in drinking water.

EPA is deleting the monitoring requirements for pentachloroethane and bis(z-chloroisopropy1) ether from the list of unregulated contaminants in the final rule. Pentachloroethane has been deleted because it is unstable in water. Bis(2-choroisopropyl) ether has been deleted because it doesnot purge well, and there are very few occurrences in drinking water. Therefore, both of these

are low priority compounds for regulation. EPA is adding tetrachloroethylene to List 1because the rulemaking for this contaminant is now included with the contaminants scheduled for regulation in June 1988

. and the resulting monitoring data will be useful (see the November 13,1985. notice for discussion of the tetrachloroethylene regulation). 

### In addition, 1,3-dichloropropene has been added to List 1because it has been detected inground waters and is measured by these analytical methods. Data gathered under this Section 1445 regulation can be used for compliance purposes when EPA promulgates regulations for tetrachloroethylene and
any other of these VOCs forwhich EPA is developing MCLs.

Table 6 presents the three lists of compounds. Table &Unregulated Contaminants

- . List I:MonitoringRequiredforAll Systems
Bromobenzene Bromodichlorome thane Bromoform Bromomethane Chlorobenzene Chlorodibromomethane Chloroethane Chloroform Chloromethane o-Chlorotoluene p-Chlorotoluene Dibromomethane m-Dichlorobenzene o-Dichlorobenzene trans-1,2-Dichloroethylene cis-l,%Dichloroe thylene Dichloromethane 1,l-Dichloroethane 1,l-Dichloropropene 1,2-Dichloropropane 1.3-Dichloropropane 1,3-Dichloropropene 2,2-Dichloropropane Ethylbenzene Styrene 1,1,2-Trichloroethane 1,1,1,2-Tetrachloroethane 1,1,2,2-Tetrachloroe thane Tetrachloroethylene 1,2,3-Trichloropropane Toluene p-Xylene o-Xylene m-Xylene

List 2: Required for VulnerableSystems Ethylene dibromide (EDB) 1.2-Dibromo-3-Chlloropropane (DBCP)

List 3: MonitoringRequired

### as 

### the State's Discretion
Bromochloromethane n-Butylbenzene Dichlorodifluoromethane Fluorotrichloromethane Hexachlorobutadiene Isopropylbenzene p-Isopropyltoluene Naphthalene n-Propylbenzene sec-Butylbenzene tert-Butylbenzene 1,2,3-Trichlorobenzene 1,2,4-Trichlorobenzene 1,2.4-Trime thylbenzene 1.3.5-Trimethylbenzene

The compounds in List 1canbe analyzed easily with the analytical methods in this final rule [Methods 502.1, 503.1, and 524.1). As previously discussed, the Agency has also developed capillary column methods [Methods 502.2 and 524.2) that are also available for the monitoring of these compounds. Monitoring for the concentrations usually increase disinfection by 

### the consecutive

TheNovember 1985proposal include repeat.monitoring 

### for unregulated VOCs [unless imposed by. the State); 

### In this finalple,however, * EPA is requiring repeat monitoring for: unregulated contaminants every five years, 

### as specified in the-SDWA Amendments of 1986,.However,EPh

new list in five years. However, States

are encouraged to require follow-up

I



### ,

### 52, 

### No. 130 

## 1 Wednesday, July 8, 1987 ’ 

### / Rules and Rendations 25711

monitoring for unregulated contaminants. The cornpositing procedure is described in the section 

### on Compliance Monitoring.



### IV. Effective Dates

These regulations have aneffective date ofjanuary 1,XX@:the laboratory performance requirements and monitoring for compliance requirements 

### (5 141.24(g)) and the unregulated monitoring and reporting requirements 

### (8 141.35 and 141.40) [Priorto the adoption ofthe compliance monitoring requirements by the State, the authority for compliance monitoring is section 1445 of the Act]. All otherprovisions promulgated in this final rulemaking (concerning MCLs, variance, and exemptions, provisions of reporting and recordkeeping) are effective Jenuary 9, 1989,asprovided in section 1412(b)(10).

V. Impact 

### Analyses

The economic impact analysis supporting 

### this finalrule is contained in “EconomichpactAnalysis of Proposed Regulations to Control Volatile Synthetic Organic Chemicals in &inking Water,” October 1985. as amended (Ref. 3). The report presents estimatesof the benefits endcosts 

### of regulatory alternatives. Also included 

### are analyses required by the Regulatory Flexibility Act and the Paperwork Reduction Act. The purpose of the assessment was to determine overall economic impacts o� the regulations. 

### The addendum to the
assessment responds to comments made during the public commentperiod. There has been no significant 

### changein the initial assessment, which showed that approximately 1300 mmmunity water supplies would 

### be expected to exceed the final standardswithout additional controls, If nearly all these systemstook actions to comply with the regulations, the total present value cost 

### of compliance to the nation would be about $zsOmillion. 

### On an annualized basis, the cost of compliance woutd be $21 million per year. Extending the 

### VOC regulations to non-community nontransient water systems will require approximately 400 additional systems io
treat their water, at a capital cost of $XI million and approximately $1.5 million
per year.

“be cost impacts on community water systems and consumera affected by volatile organic contamination vary depending upon tbe size of the 

### PWS. Very small systems which serve from 25 to 500people could be expected to increase their waterrates by approximately 54 cents per 1000 gallons of water. As a result of economies of

, scale, large community systems serving

more than 50,oOO people could be expected to increase their 

### rates only about 5 cents per 1OOOgallons.These increases would only affect systems with contaminant levels above the standards.

Under Executive Order 1m. EPA
mustjudge whether a regulation is “major’’ and, therefore, subjectto the requirements of a Repfatory Impact Analysis. This action does not constitute

a ”major” regulatory action because it will not have a major financial or adverse impact onthe country.This regulation has been reviewed by the OfficeofManagement and Budget as required 

### by Executive Order 122% and their comments are availablein the public docket.

The costs of compliance monitoring and monitoring for the unregulated contaminants arepresented in Table 7 (see Ref. 3). As noted above, composites ofup to five sources are allowed and the
costs shown in Table 7 a6sume that systems composite a number of their

sources. in addition, certain States conduct monitoring for small systems. Cornpositing of different system sources by Statesis allowed in the regulations: savings are estimated to be $500,~ per year for the initial compliance monitoring, $zOO,oOO per year

### for the initial unregulated monitoring, and $400.~ per year for the repeat compliance monitoring.



### TABLE 

### 7.-Cosrs ($ 

### MUION/YEAR)

FOR 

### MON~TORJNG FOR COMPLIANCE
WITH 

### MCLS FOR 

# vocs AND FOR 

### UNREGULATED 

### VOCs

initial Round:

VOGsubject to MCLS



## .............. ”

## ...-. $7.5 Unregulated COnta~tS.~ 

## .........-.. $1.7 Repeat Monitoring:

VOCs subject to MCLs



# _..........-........ $19.2 Urnegofated contaminants


## ........_......

1The cost for repeat monitocing of umegu­ lated contaminants will vary because the Agency will specify a new list of contaminants to be monitored in keyears. Consequent1

, contaminants other than those specified 

# L

this notice may be listed at that time.

The Regulatory Flexibility Act requires EPA to explicitly consider the effect of regulations 

### on small entities. If there is a significant effect 

### on 

### a substantial number of small systems, the Agency must seek means to minimize the effects. With respect 

### to the requirements of the Regulatory Flexiblity Act, 5 

### U.S.C. 802et seg., today’s action will not have a significant effect on a substantialnumber 

### ofsmall entities. Using the Small Business I

### 2- 

### Federal Register 

## / Vol. 52, 

### No. 130 

## / Wednesday, 

### July 8, 1987 

## / Rules 

### and Regulations

Administration’s deffinitions,a “small”
water utility is one that serves fewer than 5O.OOO people. There are about 78,500such systems. Of these, fewer than 1700 are likely to have contamination levels greater than the 

### Ma.Therefore, 

### this rule will affect about that 2 percent of the “small” systems, which does not constitute a substantial number of small systems. However, it is possible that today’s action will have a substantial impactan


### a few small systems if regulated VOCs

are found at levels higher than the MCLTherefore, the Agency has attempted to provide alternatives to the requirements whenever possible. Specifically, EPA allows compositing of samples. Small systems may choose to composite their samples and to share the analytical
costs. Also, the Agency has allowed bottled water and point-of-use devices

asconditions of receiving a variance 

### or exemption,even though decentralized
treatment is less than the Agency’s longrange goal of centralized treatment (due
to untreated taps and possible inhalation effects),to accommodatethe needs of the smaller systems with limited resources. The Agency also has given states the discretion to reduce monitoring frequency in accordance with a system’sfindings of no VOCs and its vulnerability status. Consequently, small systems which do not have VOC contamination in their water supply and

are not located in a vufnerable areamay have to monitor only infrequently. 

### In addition, very small systems are not required to sample for unregulated contaminant6 they are only required to provide a sample 

### or make the opportunity for samplingavailable to the State.

The informationcollection requirements in this rule have been submitted for approval to the Ofice of Management and Budget (OW)under the Paperwork Reducation Act, 44 U.S.C. 3501

### et seq. The informationcollection requirements are not effectiveuntil OMB approves them and a technical amendment to that effect is published in the Federal Register.



### VI. References and PublicDocket

The followingreferences are referred
to in this notice and are included in the Public Docket together with other correspondence and information.The Public Docket is available for viewing by appointment in Washington,D.C. by calling the telephone number at the beginning of this notice. All public
commentsreceived on the proposal are included in the Docket. (1)

### * U.S. EnvironmentalProtection Agency, Criteria and Standards Division,Analytical Methods/ Monitoring the VOCs in Drinking Water. June, 1987.

(2) * U.S. Environmental Protection Agency, Criteria and Standards Division.Techologies and Costs for the Removal of Volatile OrganicChemicals fromPotable Water Supplies. May, 1985.

(3)*U.S. EnvironmentalProtection Agency, 

### Office of ProgramDevelopment and Evaluation,Economicimpact Analysis of Proposed Regulations toControl Volatile Synthetic Organic Chemicalsin Drinking Water. October, 1985,as amended 1987.

(4) 

### U.S. EnvironmentalProtection Agency, Criteria and Standards Division, Summary of Commentsand EPA Responses on-the

### ProposedMCLs for the 

### VOCs,ReproposedMCLG for para-Dichlorobenzene,and “Requirements for Unregulated Contaminants.” (June 1987)

(5) Peters, 

### W., and Clark, 

### S.Memo: Risks Associated With 

### Air Emissions from Aeration of Drinking Water. 

### To Robert G. Kellam. ProgramAnalysis and Technology Section and Arthur 

### H. Perler, Science and TechnologyBranch, Criteria and Standards Division, Office 

### of Drinking Water. Nov. 13,1985. (6)* National ToxicologyProgram. Toxicology and Carcinogenesis Studies of 1,4-Dichlorobenzenein F344 Rats and B6C3K Mice (Gavage Studies],final report, 1987 (Technical Report Series No. 319).

(7j 

### U.S.EnvironmentalProtection Agency Ground Water Supply Survey January 1983. (8) U.S. EnvironmentalProtection Agency, Criteria and Standards Division. Criteria Document for orthoDichlorobenzene, metaDichlorobenzene, and parapDichlorobenzene. (June 1987)

The starred

### (‘1 documentsare avaUable for

a fee from the National Technical Information Service,U.S. Department of Commerce. 5285 Port Royal Road, Springfield, VA 22161.The toll-free number is 703/487-4650. These documents are also available for review at the Drinking WaterSupply Branch Office in 

### WAS Regional Offices.


### List of 

### Subjects 

### in 40 

### CFR Parts 141 and
142

Chemicals,Reporting and recordkeeping requirements,Water supply, Administrative practice and procedure.

Dated June19,1987.
Lee M.Thomas, Administmtor,Environmental Protection Agency.

Therefore, 40 CFR Parts 141 and 142

are amended as follows:

PART 141-CANlENDEDl

1. In Part 141: a. The adlhority citation for Part 141 continues to read asfollows:

Authority: 42 U.S.C. -1. SOOg-3,3OOj+ 300g-8.and300j-8.

­

b. 

### In 

### 0 141.2, the existing paragraph designations are removed, the existing paragraphs are arranged in alphabetim order, ahd the followingnew definition areadded:



### ­

s141.2. Definitions.

* e t * *

“Best available technology” 

### or “BAT

means thebest 

### technology, treatment techniques, 

### or other means which the Admidstrator 

### finds, after examination for efficacyunder field conditions and
not solely under laboratory conditions,

are available (taking cost into consideration). 

### For the purposes 

### of setting MCLs for synthetic organic chemicals,anyBAT must be at least as effective asgranular activated carbon.

* * t * t

.

“Non-transient non-community watei system 

### or “NTNCWS means 

### a public
water system that 

### is not 

### a community
water system and that regularly serves at least 25 of the same persons over 6

, months per year.

c t * * *

“Point-of-entrytreatment device” is 6 treatment device applied to the drinkiq
water entering 

### a house 

### or building for the purpose of reducing contaminants i~ the 

### drinking water distributed throughout the house 

### orbuilding.

“Pointsf-use treatment device” is a

. treatment device applied to #i single tap



## - used for the purpose of reducing contaminants in drinkingwater at that

one tap.

C t t t

.

c. A new paragraph [g] is added to 

### 8 14124 to read as foilows:

0 141.24 Organic chemicals other than totaltrihalomethaner,sampling and

, .. ‘ -. analyticalrequirements 

### *
t ,t

. ”‘,’ - ’ -

. . (g] Analysis ,ofthe +itaii;inints: 

### iis? 

### in 

### 0 141.61(a) 

### for purposes of.

. . 

## “i. . determiningcompliance with the maxhyqcontaminant bveis shallbe



### . conducted as followS:

.

(1) Ground-water systems’shall ..’. 

### ; sample atpoints 

### of entry to the.

. .:’ distribution system representative of

.. each well. Sampling must be conducted

.~ at the same location or 

### a more 

### :. i representative location each quaher. ’; Ground-water systems must sample .j every three months for each entry poib
to the.distribution,system except as !:2 provided in .paragraph (g](8)(i) of this .: section.