federal register

Wednesday

December 16, 1998

Part IV

Environmental

Protection Agency

40 CFR Parts 9, 141, and 142

National Primary Drinking Water

Regulations: Disinfectants and

Disinfection Byproducts; Final Rule
69390 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 9, 141, and 142

[WH–FRL–6199–8]

RIN 2040–AB82

National Primary Drinking Water

Regulations: Disinfectants and

Disinfection Byproducts

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: In this document, EPA is

finalizing maximum residual

disinfectant level goals (MRDLGs) for

chlorine, chloramines, and chlorine

dioxide; maximum contaminant level

goals (MCLGs) for four trihalomethanes

(chloroform, bromodichloromethane,

dibromochloromethane, and

bromoform), two haloacetic acids

(dichloroacetic acid and trichloroacetic

acid), bromate, and chlorite; and

National Primary Drinking Water

Regulations (NPDWRs) for three

disinfectants (chlorine, chloramines,

and chlorine dioxide), two groups of

organic disinfection byproducts (total

trihalomethanes (TTHMs)—a sum of the

four listed above, and haloacetic acids

(HAA5)—a sum of the two listed above

plus monochloroacetic acid and monoand dibromoacetic acids), and two

inorganic disinfection byproducts

(chlorite and bromate). The NPDWRs

consist of maximum residual

disinfectant levels (MRDLs) or

maximum contaminant levels (MCLs) or

treatment techniques for these

disinfectants and their byproducts. The

NPDWRs also include monitoring,

reporting, and public notification

requirements for these compounds. This

document includes the best available

technologies (BATs) upon which the

MRDLs and MCLs are based. The set of

regulations promulgated today is also

know as the Stage 1 Disinfection

Byproducts Rule (DBPR). EPA believes

the implementation of the Stage 1 DBPR

will reduce the levels of disinfectants

and disinfection byproducts in drinking

water supplies. The Agency believes the

rule will provide public health

protection for an additional 20 million

households that were not previously

covered by drinking water rules for

disinfection byproducts. In addition, the

rule will for the first time provide

public health protection from exposure

to haloacetic acids, chlorite (a major

chlorine dioxide byproduct) and

bromate (a major ozone byproduct).

The Stage 1 DBPR applies to public

water systems that are community water

systems (CWSs) and nontransient

noncommunity water systems

(NTNCWs) that treat their water with a

chemical disinfectant for either primary

or residual treatment. In addition,

certain requirements for chlorine

dioxide apply to transient

noncommunity water systems

(TNCWSs).

EFFECTIVE DATE: This regulation is

effective February 16, 1999. Compliance

dates for specific components of the rule

are discussed in the Supplementary

Information Section. The incorporation

by reference of certain publications

listed in today’s rule is approved by the

Director of the Federal Register as of

February 16, 1999.

ADDRESSES: Public comments, the

comment/response document,

applicable Federal Register documents,

other major supporting documents, and

a copy of the index to the public docket

for this rulemaking are available for

review at EPA’s Drinking Water Docket:

401 M Street, SW., Washington, DC

20460 from 9 a.m. to 4 p.m., Eastern

Standard Time, Monday through Friday,

excluding legal holidays. For access to

docket materials, please call 202/260–

3027 to schedule an appointment and

obtain the room number.

FOR FURTHER INFORMATION CONTACT: For

general information contact, the Safe

Drinking Water Hotline, Telephone

(800) 426–4791. The Safe Drinking

Water Hotline is open Monday through

Friday, excluding Federal holidays,

from 9:00 am to 5:30 pm Eastern Time.

For technical inquiries, contact Tom

Grubbs, Office of Ground Water and

Drinking Water (MC 4607), U.S.

Environmental Protection Agency, 401

M Street SW, Washington, DC 20460;

telephone (202) 260–7270. For Regional

contacts see SUPPLEMENTARY

INFORMATION.

SUPPLEMENTARY INFORMATION: This

regulation is effective 60 days after

publication of Federal Register

document for purposes of the

Administrative Procedures Act and the

Congressional Review Act. Compliance

dates for specific components of the rule

are discussed below. Solely for judicial

review purposes, this final rule is

promulgated as of 1 p.m. Eastern Time

December 30, 1998, as provided in 40

CFR 23.7.

Regulated entities. Entities regulated

by the Stage 1 DBPR are community and

nontransient noncommunity water

systems that add a disinfectant during

any part of the treatment process

including a residual disinfectant. In

addition, certain provisions apply to

transient noncommunity systems that

use chlorine dioxide. Regulated

categories and entities include:

Category Examples of regulated entities

Industry ................... Community and nontransient noncommunity water systems that treat their water with a chemical disinfectant for either primary of residual treatment. In addition, certain requirements for chlorine dioxide apply to transient noncommunity water

systems.

State, Local, Tribal,

or Federal Governments.

Same as above.

This table is not intended to be

exhaustive, but rather provides a guide

for readers regarding entities likely to be

regulated by this action. This table lists

the types of entities that EPA is now

aware could potentially be regulated by

this action. Other types of entities not

listed in this table could also be

regulated. To determine whether your

facility is regulated by this action, you

should carefully examine the

applicability criteria in § 141.130 of this

rule. If you have questions regarding the

applicability of this action to a

particular entity, contact one of the

persons listed in the preceding FOR

FURTHER INFORMATION CONTACT section

or the Regional contacts below.

Regional Contacts

I. Kevin Reilly, Water Supply Section,

JFK Federal Bldg., Room 203, Boston,

MA 02203, (617) 565–3616

II. Michael Lowy, Water Supply Section,

290 Broadway 24th Floor, New York,

NY 10007–1866, (212) 637–3830

III. Jason Gambatese, Drinking Water

Section (3WM41), 1650 Arch Street,

Philadelphia, PA 19103–2029, (215)

814–5759
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69391

IV. David Parker, Water Supply Section,

345 Courtland Street, Atlanta, GA

30365, (404) 562–9460

V. Miguel Del Toral, Water Supply

Section, 77 W. Jackson Blvd., Chicago,

IL 60604, (312) 886–5253

VI. Blake L. Atkins, Drinking Water

Section, 1445 Ross Avenue, Dallas,

TX 75202, (214) 665–2297

VII. Ralph Flournoy, Drinking Water/

Ground Water Management Branch,

726 Minnesota Ave., Kansas City, KS

66101, (913) 551–7374

VIII. Bob Clement, Public Water Supply

Section (8P2–W–MS), 999 18th Street,

Suite 500, Denver, CO 80202–2466,

(303) 312–6653

IX. Bruce Macler, Water Supply Section,

75 Hawthorne Street, San Francisco,

CA 94105, (415) 744–1884

X. Wendy Marshall, Drinking Water

Unit, 1200 Sixth Avenue (OW–136),

Seattle, WA 98101, (206) 553–1890

Abbreviations Used in This Document

AWWA: American Water Works

Association

AWWSCo: American Water Works

Service Company

BAT: Best available technology

BDCM: Bromodichloromethane

CDC: Centers for Disease Control and

Prevention

C.I.: Confidence Intervals

CMA: Chemicals Manufacturers

Association

CPE: Comprehensive performance

evaluation

CWS: Community water system

DBCM: Dibromochloromethane

DBP: Disinfection byproducts

D/DBP: Disinfectants and disinfection

byproducts

DBPR: Disinfection Byproducts Rule

DBPRAM: Disinfection byproducts

regulatory analysis model

DCA: Dichloroacetic acid

DOC: Dissolved organic carbon

DWSRF: Drinking Water State Revolving

Fund

EC: Enhanced coagulation

EJ: Environmental justice

EPA: United States Environmental

Protection Agency

ESWTR: Enhanced Surface Water

Treatment Rule

FACA: Federal Advisory Committee Act

GAC10: Granular activated carbon with

ten minute empty bed contact time

and 180 day reactivation frequency

GAC20: Granular activated carbon with

twenty minute empty bed contact

time and 180 day reactivation

frequency

GDP: Gross Domestic Product

GWR: Groundwater rule

HAA5: Haloacetic acids

(five)(chloroacetic acid, dichloroacetic

acid, trichloroacetic acid, bromoacetic

acid, and dibromoacetic acid)

HAN: Haloacetonitriles

ICR: Information collection rule (issued

under section 1412(b) of the SDWA)

ILSI: International Life Sciences

Institute

IESTWR: Interim Enhanced Surface

Water Treatment Rule

LOAEL: Lowest Observed Adverse

Effect Level

LT1ESTWR: Long-Term 1Enhanced

Surface Water Treatment Rule

MCL: Maximum contaminant level

MCLG: Maximum contaminant level

goal

M–DBP: Microbial and Disinfectants/

Disinfection Byproducts

mg/L: Milligrams per liter

MRDL: Maximum residual disinfectant

level

MRDLG: Maximum residual disinfectant

level goal

NDWAC: National Drinking Water

Advisory Council

NIST: National Institute of Science and

Technology

NOAEL: No Observed Adverse Effect

Level

NODA: Notice of Data Availability

NOM: Natural organic matter

NPDWR: National Primary Drinking

Water Regulation

NTNCWS: Nontransient noncommunity

water system

NTP: National Toxicology Program

NTTAA: National Technology Transfer

and Advancement Act

NTU: Nephelometric turbidity unit

OMB: Office of Management and Budget

PAR: Population attributable risk

PBMS: Performance based measurement

system

PE: Performance evaluation

PODR: Point of diminishing return

PQL: Practical quantitation limit

PWS: Public water system

QC: Quality control

Reg. Neg.: Regulatory Negotiation

RFA: Regulatory Flexibility Act

RfD: Reference dose

RIA: Regulatory impact analysis

RSC: Relative source contribution

SAB: Science Advisory Board

SBREFA: Small Business Regulatory

Enforcement Fairness Act

SDWIS: Safe Drinking Water

Information System

SUVA: Specific ultraviolet absorbance

SDWA: Safe Drinking Water Act, or the

‘‘Act,’’ as amended 1996

SWTR: Surface Water Treatment Rule

TC: Total coliforms

TCA: Trichloroacetic acid

TCR: Total Coliform Rule

TOC: Total organic carbon

TOX: Total organic halides

TTHM: Total trihalomethanes

(chloroform, bromdichloromethane,

dibromochloromethane, and

bromoform)

TNCWS: Transient noncommunity

water systems

TWG: Technical work group

UMRA: Unfunded mandates reform act

URTH: Unreasonable risk to health

WIDB: Water Industry Data Base

Table of Contents

I. Background

A. Statutory Requirements and Legal

Authority

B. Regulatory History

1. Existing Regulations

2. Public Health Concerns To Be

Addressed

3. Regulatory Negotiation Process

4. Federal Advisory Committee Process

5. 1997 and 1998 Notices of Data

Availability (NODA)

II. Summary of Final Stage 1 Disinfection

Byproduct Rule

A. Applicability

B. MRDLGs and MRDLs for Disinfectants

C. MCLGs and MCLs for TTHMs, HAA5,

Chlorite, and Bromate

D. Treatment Technique for Disinfection

Byproducts Precursors

E. BAT for Disinfectants, TTHMs, HAA5,

Chlorite, and Bromate

F. Compliance Monitoring Requirements

G. Analytical Methods

H. Laboratory Certification Criteria

I. Variances and Exemptions

J. State Recordkeeping, Primacy, Reporting

Requirements

K. System Reporting Requirements

L. Guidance Manuals

M. Regulation Review

III. Explanation of Final Rule

A. MCLGs/MRDLGs

1. MCLG for Chloroform

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

2. MCLG for Bromodichloromethane

(BDCM)

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

3. MCLG for Dibromochloromethane

(DBCM)

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

4. MCLG for Bromoform

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

5. MCLG for Dichloroacetic Acid (DCA)

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

6. MCLG for Trichloroacetic Acid (TCA)

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

7. MCLG for Chlorite and MRDLG for

Chlorine Dioxide

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

8. MCLG for Bromate

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments
69392 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

9. MCLG for Chloral Hydrate

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

10. MRDLG for Chlorine

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

11. MRDLG for Chloramine

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

B. Epidemiology

1. Cancer Epidemiology

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

2. Reproductive and Developmental

Epidemiology

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

C. MCLs and BAT for TTHM, HAA5,

Chlorite, and Bromate; MRDLs and BAT

for Chlorine, Chloramines, and Chlorine

Dioxide

1. MCLs for TTHMs and HAA5

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

2. MCL for Bromate

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

3. MCL for Chlorite

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

4. MRDL for Chlorine

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

5. MRDL for Chloramines

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

6. MRDL for Chlorine Dioxide

a. Today’s Rule

b. Background Analysis

c. Summary of Comments

D. Treatment Technique Requirement

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

E. Predisinfection Disinfection Credit

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

F. Requirements for Systems to Use

Qualified Operators

G. Analytical Methods

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

4. Performance Based Measurement

Systems

H. Monitoring Requirements

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

I. Compliance Schedules

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

J. Public Notice Requirements

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

K. System Reporting and Record Keeping

Requirements

1. Today’s Rule

2. Summary of Comments

L. State Recordkeeping, Primacy, and

Reporting Requirements

1. State Recordkeeping Requirements

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

2. Special Primacy Requirements

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

3. State Reporting Requirements

a. Today’s Rule

b. Background and Analysis

c. Summary of Comments

M. Variances and Exemptions

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

N. Laboratory Certification and Approval

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

IV. Economic Analysis

A. Today’s Rule

B. Background

1. Overview of RIA for the Proposed Rule

2. Factors Affecting Changes to the 1994

RIA

a. Changes in Rule Criteria

b. New Information Affecting DBP

Occurrence and Compliance Forecast

c. New Epidemiology Information

C. Cost Analysis

1. Revised Compliance Forecast

2. System Level Unit Costs

3. National Costs

D. Benefits Analysis

1. Exposure Assessment

2. Baseline Risk Assessment Based on

TTHM Toxicological Data

3. Baseline Analysis Based on

Epidemiology Data

4. Exposure Reduction Analysis

5. Monetization of Health Endpoints

E. Net Benefits Analysis

F. Summary of Comments

V. Other Requirements

A. Regulatory Flexibility Analysis

1. Today’s Rule

2. Background and Analysis

3. Summary of Comments

B. Paperwork Reduction Act

C. Unfunded Mandates Reform Act

1. Summary of UMRA Requirements

2. Written Statement for Rules with Federal

Mandates of $100 million or More

a. Authorizing Legislation

b. Cost Benefit Analysis

c. Estimates of Future Compliance Costs

and Disproportionate Budgetary Effects

d. Macro-economic Effects

e. Summary of State, Local, and Tribal

Government and TheirConcerns

f. Regulatory Alternative Considered

3. Impacts on Small Governments

D. National Technology Transfer and

Advancement Act

E. Executive Order 12866: Regulatory

Planning and Review

F. Executive Order 12898: Environmental

Justice

G. Executive Order 13045: Protection of

Children from Environmental Health

Risks and Safety Risks

H. Consultation with the Science Advisory

Board, National Drinking Water

Advisory Council, and the Secretary of

Health and Human Services

I. Executive Order 12875: Enhancing the

Intergovernmental Partnership

J. Executive Order 13084: Consultation and

Coordination with Indian Tribal

Governments

K. Submission to Congress and the General

Accounting Office

L. Likely Effect of Compliance with the

Stage 1 DBPR on the Technical,

Financial, and Managerial Capacity of

Public Water Systems

VI. References

I. Background

A. Statutory Requirements and Legal

Authority

The Safe Drinking Water Act (SDWA

or the Act), as amended in 1986,

requires USEPA to publish a ‘‘maximum

contaminant level goal’’ (MCLG) for

each contaminant which, in the

judgement of the USEPA Administrator,

‘‘may have any adverse effect on the

health of persons and which is known

or anticipated to occur in public water

systems’’ (Section 1412(b)(3)(A)).

MCLGs are to be set at a level at which

‘‘no known or anticipated adverse effect

on the health of persons occur and

which allows an adequate margin of

safety’’ (Section 1412(b)(4)).

The Act was amended in August

1996. As a result of these Amendments,

several of these provisions were

renumbered and augmented with

additional language. Other sections

were added establishing new drinking

water requirements. These

modifications are outlined below.

The Act also requires that at the same

time USEPA publishes an MCLG, which

is a non-enforceable health goal, it also

must publish a National Primary

Drinking Water Regulation (NPDWR)

that specifies either a maximum

contaminant level (MCL) or treatment

technique (Sections 1401(1) and

1412(a)(3)). USEPA is authorized to

promulgate a NPDWR ‘‘that requires the

use of a treatment technique in lieu of

establishing a MCL,’’ if the Agency finds

that ‘‘it is not economically or

technologically feasible to ascertain the

level of the contaminant’’.

As amended, EPA’s general authority

to set a maximum contaminant level

goal (MCLG) and National Primary

Drinking Water Regulation (NPDWR)

applies to contaminants that may ‘‘have

an adverse effect on the health of

persons,’’ that are ‘‘known to occur or

there is a substantial likelihood that the

contaminant will occur in public water
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69393

systems with a frequency and at levels

of public health concern,’’ and for

which ‘‘in the sole judgement of the

Administrator, regulation of such

contaminant presents a meaningful

opportunity for health risk reduction for

persons served by public water

systems’’ (SDWA Section 1412(b)(1)(A)).

The amendments, also require EPA,

when proposing a NPDWR that includes

an MCL or treatment technique, to

publish and seek public comment on an

analysis of health risk reduction and

cost impacts. In addition, EPA is

required to take into consideration the

effects of contaminants upon sensitive

subpopulations (i.e. infants, children,

pregnant women, the elderly, and

individuals with a history of serious

illness), and other relevant factors.

(Section 1412 (b)(3)(C)).

The amendments established a

number of regulatory deadlines,

including schedules for a Stage 1

Disinfection Byproduct Rule (DBPR), an

Interim Enhanced Surface Water

Treatment Rule (IESWTR), a Long-Term

Final Enhanced Surface Water

Treatment Rule (LTESWTR) affecting

Public Water Systems (PWSs) that serve

under 10,000 people, and a Stage 2

DBPR (Section 1412(b)(2)(C)). The Act

as amended also requires EPA to

promulgate regulations to address filter

backwash (Section 1412(b)(14)). Finally,

the Act requires EPA to promulgate

regulations specifying criteria for

requiring disinfection ‘‘as necessary’’ for

ground water systems (Section 1412

(b)(8)).

Finally, as part of the 1996 SDWA

Amendments, recordkeeping

requirements were modified to apply to

‘‘every person who is subject to a

requirement of this title or who is a

grantee’’ (Section 1445 (a)(1)(A)). Such

persons are required to ‘‘establish and

maintain such records, make such

reports, conduct such monitoring, and

provide such information as the

Administrator may reasonably require

by regulation * * * ’’.

B. Regulatory History

1. Existing Regulations

Surface Water Treatment Rule. Under

the Surface Water Treatment Rule

(SWTR) (54 FR 27486, June 29, 1989)

(EPA,1989a), EPA set maximum

contaminant level goals of zero for

Giardia lamblia, viruses, and Legionella;

and promulgated NPDWR for all PWSs

using surface water sources or ground

water sources under the direct influence

of surface water. The SWTR includes

treatment technique requirements for

filtered and unfiltered systems that are

intended to protect against the adverse

health effects of exposure to Giardia

lamblia, viruses, and Legionella, as well

as many other pathogenic organisms.

Briefly, those requirements include: (1)

requirements for a maintenance of a

disinfectant residual in the distribution

system; (2) removal and/or inactivation

of 3 logs (99.9%) for Giardia and 4 logs

(99.99%) for viruses; (3) combined filter

effluent performance of 5 nephelometric

turbidity unit (NTU) as a maximum and

0.5 NTU at 95th percentile monthly,

based on 4-hour monitoring for

treatment plants using conventional

treatment or direct filtration (with

separate standards for other filtration

technologies); and (4) watershed

protection and other requirements for

unfiltered systems.

Total Coliform Rule. The Total

Coliform Rule (TCR) (54 FR 27544; June

29, 1989) applies to all public water

systems (EPA, 1989b). This regulation

sets compliance with the MCL for total

coliforms (TC) as follows. For systems

that collect 40 or more samples per

month, no more than 5.0% of the

samples may be TC-positive; for those

that collect fewer than 40 samples, no

more than one sample may be TCpositive. In addition, if two consecutive

samples in the system are TC-positive,

and one is also fecal coliform or E. colipositive, then this is defined as an acute

violation of the MCL. If a system

exceeds the MCL, it must notify the

public using mandatory language

developed by the EPA. The required

monitoring frequency for a system

depends on the number of people

served and, ranges from 480 samples per

month for the largest systems to once

annually for certain of the smallest

systems. All systems must have a

written plan identifying where samples

are to be collected.

If a system has a TC-positive sample,

it must test that sample for the presence

of fecal coliforms or E. coli. The system

must also collect a set of repeat samples,

and analyze for TC (and fecal coliform

or E. coli) within 24 hours of the first

TC-positive sample.

The TCR also requires an on-site

inspection every 5 years (10 years for

non-community systems using only

protected and disinfected ground water)

for each system that collects fewer than

five samples per month. This on-site

inspection (referred to as a sanitary

survey) must be performed by the State

or by an agent approved by the State.

Total Trihalomethane Rule. In

November 1979 (44 FR 68624) (EPA,

1979) EPA set an interim MCL for total

trihalomethanes (TTHM) of 0.10

milligrams per liter (mg/L) as an annual

average. Compliance is defined on the

basis of a running annual average of

quarterly averages of all samples. The

value for each sample is the sum of the

measured concentrations of chloroform,

bromodichloromethane (BDCM),

dibromochloromethane (DBCM) and

bromoform.

The interim TTHM standard only

applies to community water systems

using surface water and/or ground water

serving at least 10,000 people that add

a disinfectant to the drinking water

during any part of the treatment process.

At their discretion, States may extend

coverage to smaller PWSs; however,

most States have not exercised this

option.

Information Collection Rule. The

Information Collection Rule (ICR) is a

monitoring and data reporting rule that

was promulgated on May 14, 1996 (61

FR 24354) (EPA, 1996a). The purpose of

the ICR is to collect occurrence and

treatment information to help evaluate

the need for possible changes to the

current SWTR and existing microbial

treatment practices, and to help evaluate

the need for future regulation for

disinfectants and disinfection

byproducts (D/DBPs). The ICR will

provide EPA with additional

information on the national occurrence

in drinking water of (1) chemical

byproducts that form when disinfectants

used for microbial control react with

naturally occurring compounds already

present in source water and (2) diseasecausing microorganisms, including

Cryptosporidium, Giardia, and viruses.

The ICR will also provide engineering

data on how PWSs currently control for

such contaminants. This information is

being collected because the 1992

Regulatory Negotiating Committee

(henceforth referred to as the Reg. Neg.

Committee) on microbial pathogens and

disinfectants and DBPs concluded that

additional information was needed to

assess the potential health problem

created by the presence of DBPs and

pathogens in drinking water and to

assess the extent and severity of risk in

order to make sound regulatory and

public health decisions. The ICR will

also provide information to support

regulatory impact analyses for various

regulatory options, and to help develop

monitoring strategies for cost-effectively

implementing regulations.

The ICR pertains to large public water

systems serving populations at least

100,000; a more limited set of ICR

requirements pertain to ground water

systems serving between 50,000 and

100,000 people. About 300 PWSs

operating 500 treatment plants are

involved with the extensive ICR data

collection. Under the ICR, these PWSs

monitor for water quality factors

affecting DBP formation and DBPs
69394 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

within the treatment plant and in the

distribution system monthly for 18

months. In addition, PWSs must

provide operating data and a description

of their treatment plan design and

surface water systems must monitor for

bacteria, viruses, and protozoa. Finally,

a subset of PWSs must perform

treatment studies, using either granular

activated carbon (GAC) or membrane

processes, to evaluate DBP precursor

removal and control of DBPs.

Monitoring for treatment study

applicability began in September 1996.

The remaining occurrence monitoring

began in July 1997.

One initial intent of the ICR was to

collect pathogen occurrence data and

other information for use in developing

the IESWTR and to estimate national

costs for various treatment options.

However, because of delays in

promulgating the ICR and technical

difficulties associated with laboratory

approval and review of facility sampling

plans, ICR monitoring did not begin

until July 1, 1997, which was later than

originally anticipated. As a result of this

delay and the new statutory deadlines

for promulgating the Stage 1 DBPR and

IESWTR in November of 1998 (resulting

from the 1996 SDWA amendments), ICR

data were not available in time to

support these rules. In place of the ICR

data, the Agency worked with

stakeholders to identify other sources of

data developed since 1994 that could be

used to support the development of the

Stage 1 DBPR and IESWTR. EPA will

continue to work with stakeholders in

analyzing and using the comprehensive

ICR data and research for developing

future Enhanced Surface Water

Treatment requirements and the Stage 2

DBPR.

2. Public Health Concerns to be

Addressed

EPA’s main mission is the protection

of human health and the environment.

When carrying out this mission, EPA

must often make regulatory decisions

with less than complete information and

with uncertainties in the available

information. EPA believes it is

appropriate and prudent to err on the

side of public health protection when

there are indications that exposure to a

contaminant may present risks to public

health, rather than take no action until

risks are unequivocally proven.

In regard to the Stage 1 DBPR, EPA

recognizes that the assessment of public

health risks from disinfection of

drinking water currently relies on

inherently difficult and preliminary

empirical analysis. On one hand,

epidemiologic studies of the

populations in various geographic areas

are hampered by difficulties of study

design, scope, and sensitivity. On the

other hand, uncertainty is involved in

the interpretation of results using high

dose animal toxicological studies of a

few of the numerous byproducts that

occur in disinfected drinking water to

estimate the risk to humans from

chronic exposure to low doses of these

and other byproducts. Such studies of

individual DBPs is insufficient to

characterize risks from exposure to the

entire mixture of DBPs in disinfected

drinking water. While recognizing these

uncertainties, EPA continues to believe

that the Stage 1 DBPR is necessary for

the protection of public health from

exposure to potentially harmful DBPs.

A fundamental component in

assessing the risk for a contaminant is

the number of people that may be

exposed to the parameter of concern. In

this case, there is a very large

population potentially exposed to DBPs

through drinking water in the U.S. Over

200 million people are served by PWSs

that apply a disinfectant (e.g., chlorine)

to water in order to provide protection

against microbial contaminants. While

these disinfectants are effective in

controlling many microorganisms, they

react with natural organic and inorganic

matter in the water to form DBPs, some

of which may pose health risks. One of

the most complex questions facing

water supply professionals is how to

minimize the risks from DBPs and still

maintain adequate control over

microbial contaminants. Because of the

large number of people exposed to

DBPs, there is a substantial concern for

any risks associated with DBPs that may

impact public health.

Since the discovery of chlorination

byproducts in drinking water in 1974,

numerous toxicological studies have

been conducted. Results from these

studies have shown several DBPs (e.g.,

bromodichloromethane, bromoform,

chloroform, dichloroacetic acid, and

bromate) to be carcinogenic in

laboratory animals . Some DBPs (e.g.,

chlorite, BDCM, and certain haloacetic

acids) have also been shown to cause

adverse reproductive or developmental

effects in laboratory animals. Although

many of these studies have been

conducted at high doses, EPA believes

the studies provide evidence that DBPs

present a potential public health risk

that needs to be addressed.

In the area of epidemiology, a number

of epidemiology studies have been

conducted to investigate the

relationship between exposure to

chlorinated surface water and cancer.

While EPA cannot conclude there is a

causal link between exposure to

chlorinated surface water and cancer,

these studies have suggested an

association, albeit small, between

bladder, rectal, and colon cancer and

exposure to chlorinated surface water.

While there are fewer published

epidemiology studies that have been

conducted to evaluate the possible

relationship between exposure to

chlorinated surface water and

reproductive and developmental effects,

a recent study has suggested an

association between early term

miscarriage and exposure to drinking

water with elevated trihalomethane

levels. In addition to this study, another

new study reported a small increased

risk of neural tube defects associated

with consumption of drinking water

containing high levels of TTHMs.

However, no significant associations

were observed with individual THMs,

HAAs, and haloacetonitriles (HANs)

and adverse outcomes in this study. As

with cancer, EPA cannot conclude at

this time there is a causal link between

exposure to DBPs and reproductive and

developmental effects.

While EPA recognizes there are data

deficiencies in the information on the

health effects from the DBPs and the

levels at which they occur, the Agency

believes the weight-of-evidence

presented by the available

epidemiological studies on chlorinated

drinking water and toxicological studies

on individual DBPs support a potential

hazard concern and warrant regulatory

action at this time to reduce DBP levels

in drinking water. Recognizing the

deficiencies in the existing data, EPA

believes the incremental two-stage

approach for regulating DBPs, agreed

upon by the regulatory negotiation

process, is prudent and necessary to

protect public health and meet the

requirements of the SDWA.

In conclusion, because of the large

number of people exposed to DBPs and

the different potential health risks (e.g.,

cancer and adverse reproductive and

developmental effects) that may result

from exposure to DBPs, EPA believes

the Stage 1 DBPR is needed to further

prevent potential health effects from

DBPs, beyond that controlled for by the

1979 total trihalomethane rule. Both the

Reg. Neg. Committee for the 1994

proposed rule and the Microbial and

Disinfectants/Disinfection Byproducts

Advisory Committee (henceforth cited

as the M-DBP Advisory Committee)

formed in March 1997 under the Federal

Advisory Committee Act (FACA),

agreed with the need for the Stage 1

DBPR to reduce potential risks from

DBPs in the near term, while

acknowledging additional information

is still needed for the Stage 2 DBPR

(especially on health effects),
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69395

3. Regulatory Negotiation Process

In 1992 EPA initiated a negotiated

rulemaking to address public health

concerns associated with disinfectants,

DBPs, and microbial pathogens. The

negotiators included representatives of

State and local health and regulatory

agencies, public water systems, elected

officials, consumer groups and

environmental groups. The Reg. Neg.

Committee met from November 1992

through June 1993.

Early in the process, the negotiators

agreed that large amounts of information

necessary to understand how to

optimize the use of disinfectants to

concurrently minimize microbial and

DBP risk on a plant-specific basis were

unavailable. Nevertheless, the Reg. Neg.

Committee agreed that EPA propose a

Stage 1 DBPR to extend coverage to all

community and nontransient

noncommunity water systems that use

disinfectants, reduce the current TTHM

MCL, regulate additional DBPs, set

limits for the use of disinfectants, and

reduce the level of organic precursor

compounds in the source water that

may react with disinfectants to form

DBPs.

EPA’s most significant concern in

developing regulations for disinfectants

and DBPs was the need to ensure that

adequate treatment be maintained for

controlling risks from microbial

pathogens. One of the major goals

addressed by the Reg. Neg. Committee

was to develop an approach that would

reduce the level of exposure from

disinfectants and DBPs without

undermining the control of microbial

pathogens. The intention was to ensure

that drinking water is microbiologically

safe at the limits set for disinfectants

and DBPs and that these chemicals do

not pose an unacceptable health risk at

these limits. Thus, the Reg. Neg.

Committee also considered a range of

microbial issues and agreed that EPA

should also propose a companion

microbial rule (IESWTR).

Following months of intensive

discussions and technical analysis, the

Reg. Neg. Committee recommended the

development of three sets of rules: a

two-staged approach for the DBPs

(proposal: 59 FR 38668, July 29, 1994)

(EPA, 1994a), an ‘‘interim’’ ESWTR

(proposal: 59 FR 38832, July 29, 1994)

(EPA, 1994b), and an information

collection rule (proposal: 59 FR 6332,

February 10, 1994) (EPA, 1994c)

(promulgation: 61FR24354, May 14,

1996) (EPA, 1996a). The approach used

in developing these proposals

considered the constraints of

simultaneously treating water to control

for both microbial contaminants and D/

DBPs.

The Reg. Neg. Committee agreed that

the schedules for IESWTR and

LTESWTR should be ‘‘linked’’ to the

schedule for the Stage 1 DBPR to assure

simultaneous compliance and a

balanced risk-risk based

implementation. The Reg. Neg.

Committee agreed that additional

information on health risk, occurrence,

treatment technologies, and analytical

methods needed to be developed in

order to better understand the risk-risk

tradeoff, and how to accomplish an

overall reduction in health risks to both

pathogens and D/DBPs.

Finally the Reg. Neg. Committee

agreed that to develop a reasonable set

of rules and to understand more fully

the limitations of the current SWTR,

additional field data were critical. Thus,

a key component of the regulation

negotiation agreement was the

promulgation of the ICR previously

described.

4. Federal Advisory Committee Process

In May 1996, the Agency initiated a

series of public informational meetings

to provide an update on the status of the

1994 proposal and to review new data

related to microbial and DBP regulations

that had been developed since July

1994. In August 1996, Congress enacted

the 1996 SDWA Amendments which

contained a number of new

requirements, as discussed above, as

well as specifying deadlines for final

promulgation of the IESWTR and Stage

1 DBPR. To meet these deadlines and to

maximize stakeholder participation, the

Agency established the M–DBP

Advisory Committee under FACA in

March 1997, to collect, share, and

analyze new information and data, as

well as to build consensus on the

regulatory implications of this new

information. The Committee consisted

of 17 members representing EPA, State

and local public health and regulatory

agencies, local elected officials, drinking

water suppliers, chemical and

equipment manufacturers, and public

interest groups.

The M–DBP Advisory Committee met

five times in March through July 1997

to discuss issues related to the IESWTR

and Stage 1 DBPR. Technical support

for these discussions was provided by a

Technical Work Group (TWG)

established by the Committee at its first

meeting in March 1997. The

Committee’s activities resulted in the

collection, development, evaluation,

and presentation of substantial new data

and information related to key elements

of both proposed rules. The Committee

reached agreement on a number of

major issues that were discussed in

Notices of Data Availability (NODA) for

the IESWTR (62 FR 59486, November 3,

1997) (EPA, 1997a) and the Stage 1

DBPR (62 FR 59388, November 3, 1997)

(EPA, 1997b). The major

recommendations addressed by the

Committee and in the NODAs were to:

(1) Maintain the proposed MCLs for

TTHM, HAA5, and bromate; (2) modify

the enhanced coagulation requirements

as part of DBP control; (3) include a

microbial benchmarking/profiling to

provide a methodology and process by

which a PWS and the State, working

together, assure that there will be no

significant reduction in microbial

protection as the result of modifying

disinfection practices in order to meet

MCLs for TTHM and HAA5; (4)

continue credit for compliance with

applicable disinfection requirements for

disinfection applied at any point prior

to the first customer, consistent with the

existing SWTR; (5) modify the turbidity

performance requirements and add

requirements for individual filters; (6)

establish an MCLG for Cryptosporidium;

(7) add requirements for removal of

Cryptosporidium; (8) provide for

mandatory sanitary surveys; and (9)

make a commitment to additional

analysis of the role of Cryptosporidium

inactivation as part of a multiple barrier

concept in the context of a subsequent

Federal Register microbial proposal. The

new data and analysis supporting the

technical areas of agreement were

summarized and explained at length in

EPA’s 1997 NODAs (EPA, 1997a and

EPA, 1997b).

5. 1997 and 1998 Notices of Data

Availability

In November 1997 EPA published a

NODA (USEPA, 1997b) that

summarized the 1994 proposal;

described new data and information that

the Agency has obtained and analyses

that have been developed since the

proposal; provided information

concerning the July 1997

recommendations of the M–DBP

Advisory Committee on key issues

related to the proposal (described

above); and requested comment on these

recommendations, as well as on other

regulatory implications that flow from

the new data and information. The

Agency solicited additional data and

information that were relevant to the

issues discussed in the DBP NODA. EPA

also requested that any information the

Agency should consider as part of the

final rule development process

regarding data or views submitted to the

Agency since the close of the comment

period on the 1994 proposal, be

formally resubmitted during the 90-day
69396 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

comment period unless already in the

underlying record in the docket for the

NODA.

In March 1998, EPA issued a second

DBP NODA (EPA, 1998a) that

summarized new health effects

information received and analyzed since

the November 1997 NODA and

requested comments on several issues

related to the simultaneous compliance

with the Stage 1 DBPR and the Lead and

Copper Rule. The 1998 NODA indicated

EPA was considering increasing the

MCLG for chloroform from zero to 0.3

mg/L and the proposed MCLG for

chlorite from 0.08 mg/L to 0.8 mg/L.

EPA also requested comment on

increasing the Maximum Residual

Disinfection Level Goal (MRDLG) for

chlorine dioxide from 0.3 mg/L to 0.8

mg/L. Today’s final rule was developed

based on the outcome of the 1992 Reg.

Neg., the 1994 proposed rule, the 1997

FACA process, and both the 1997 and

1998 DBP NODAs, as well as a wide

range of technical comments from

stakeholders and members of the public.

A summary of today’s rule follows.

II. Summary of Final Stage 1

Disinfection Byproduct Rule

A. Applicability

The final Stage 1 DBPR applies to

community water systems (CWSs) and

nontransient noncommunity water

systems (NTNCWs) that treat their water

with a chemical disinfectant for either

primary or residual treatment. In

addition, certain requirements for

chlorine dioxide apply to transient

noncommunity water systems

(TNCWSs).

B. MRDLGs and MRDLs for Disinfectants

EPA is finalizing the following

MRDLGs and maximum residual

disinfectant levels (MRDLs) for chlorine,

chloramines, and chlorine dioxide in

Table II–1.

TABLE II–1.—MRDLGS AND MRDLS FOR DISINFECTANTS

Disinfectant residual MRDLG (mg/L) MRDL (mg/L)

Chlorine ..................................................................................................................................................... 4 (as Cl2) 4.0 (as Cl2)

Chloramine ................................................................................................................................................ 4 (as Cl2) 4.0 (as Cl2)

Chlorine Dioxide ........................................................................................................................................ 0.8 (as ClO2) 0.8 (as ClO2)

C. MCLGs and MCLs for TTHMs, HAA5,

Chlorite, and Bromate

EPA is finalizing the MCLGs and

MCLs in Table II–2.

TABLE II–2.—MCLGS AND MCLS FOR DISINFECTION BYPRODUCTS

Disinfection byproducts MCLG (mg/L) MCL (mg/L)

Total trihalomethanes (TTHM) 1 ................................................................................................................................... N/A 0.080

—Chloroform ......................................................................................................................................................... 0 ......................

—Bromodichloromethane ..................................................................................................................................... 0 ......................

—Dibromochloromethane ..................................................................................................................................... 0.06 ......................

—Bromoform ......................................................................................................................................................... 0 ......................

Haloacetic acids (five) (HAA5) 2 ................................................................................................................................... N/A 0.060

—Dichloroacetic acid ............................................................................................................................................ 0 ......................

—Trichloroacetic acid ........................................................................................................................................... 0.3 ......................

Chlorite ......................................................................................................................................................................... 0.8 1.0

Bromate ........................................................................................................................................................................ 0 0.010

N/A—Not applicable because there are no individual MCLGs for TTHMs or HAAs.

1Total trihalomethanes is the sum of the concentrations of chloroform, bromodichloromethane, dibromochloromethane, and bromoform.

2 Haloacetic acids (five) is the sum of the concentrations of mono-, di-, and trichloroacetic acids and mono- and dibromoacetic acids.

D. Treatment Technique for Disinfection

Byproduct Precursors

Water systems that use surface water

or ground water under the direct

influence of surface water and use

conventional filtration treatment are

required to remove specified

percentages of organic materials

(measured as total organic carbon) that

may react with disinfectants to form

DBPs as indicated in Table II–3.

Removal will be achieved through a

treatment technique (enhanced

coagulation or enhanced softening)

unless a system meets alternative

criteria discussed in Section III.D.

TABLE II–3.—REQUIRED REMOVAL OF TOTAL ORGANIC CARBON BY ENHANCED COAGULATION AND ENHANCED SOFTENING

FOR SUBPART H SYSTEMS USING CONVENTIONAL TREATMENT a,b,c

Source Water TOC (mg/L)

Source Water Alkalinity (mg/L as

CaCO3) (percent)

0–60 >60–120 >120

>2.0–4.0 ................................................................................................................................................... 35.0 25.0 15.0

>4.0–8.0 ................................................................................................................................................... 45.0 35.0 25.0
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69397

TABLE II–3.—REQUIRED REMOVAL OF TOTAL ORGANIC CARBON BY ENHANCED COAGULATION AND ENHANCED SOFTENING

FOR SUBPART H SYSTEMS USING CONVENTIONAL TREATMENT a,b,c—Continued

Source Water TOC (mg/L)

Source Water Alkalinity (mg/L as

CaCO3) (percent)

0–60 >60–120 >120

>8.0 .......................................................................................................................................................... 50.0 40.0 30.0

aSystems meeting at least one of the conditions in Section 141.135(a)(2) (i)–(vi) of the rule are not required to operate the removals in this

table. bSoftening systems meeting one of the two alternative compliance criteria in Section 141.135(a)(3) of the rule are not required to meet the removals in this table. cSystems practicing softening must meet the TOC removal requirements in the last column to the right.

E. BAT for Disinfectants, TTHMs,

HAA5, Chlorite, and Bromate

Under the SDWA, EPA must specify

the BAT for each MCL (or MRDL) that

is set. PWS that are unable to achieve an

MCL or MRDL may be granted a

variance if they use the BAT and meet

other requirements (see section III.M for

a discussion of variances and

exemptions). Table II.4 includes the

BATs for each of the MCLs or MRDLs

that EPA is promulgating in today’s

Stage 1 DBPR.

TABLE II–4.—BAT FOR DISINFECTANTS AND DISINFECTION BYPRODUCTS

Disinfectant/DBP Best available technology

Disinfectants

Chlorine residual .................. Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to

reduce disinfectant levels.

Chloramine residual ............. Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to

reduce disinfectant levels.

Chlorine dioxide residual ...... Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to

reduce disinfectant levels.

Disinfection Byproducts

Total trihalomethanes ........... Enhanced coagulation or enhanced softening or GAC10*, with chlorine as the primary and residual disinfectant.

Total haloacetic acids ........... Enhanced coagulation or enhanced softening or GAC10*, with chlorine as the primary and residual disinfectant.

Chlorite ................................. Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to

reduce disinfectant levels.

Bromate ................................ Control of ozone treatment process to reduce production of bromate.

* GAC10 means granular activated carbon with an empty bed contact time of 10 minutes and reactivation frequency for GAC of no more than

six months.

F. Compliance Monitoring Requirements

Compliance monitoring requirements

are explained in Section III.H of today’s

rule. EPA has developed routine and

reduced compliance monitoring

schemes for disinfectants and DBPs to

be protective from different types of

health concerns, including acute and

long-term effects.

G. Analytical Methods

EPA has approved five methods for

measurement of free chlorine, four

methods for combined chlorine, and six

for total chlorine. EPA has also

approved two methods for the

measurement of chlorine dioxide

residuals; three methods for the

measurement of HAA5; three methods

for the measurement of TTHMs; three

methods for the measurement of TOC/

Dissolved Organic Carbon (DOC); two

methods for the monthly measurement

of chlorite and one method for the daily

monitoring of chlorite; two methods for

bromide; one method for the

measurement of bromate; and one

method for the measurement of UV254.

Finally, EPA approved all methods

allowed in § 141.89(a) for measuring

alkalinity. These issues are discussed in

more detail in section III.G.

H. Laboratory Certification Criteria

Consistent with other drinking water

regulations, determinations of

compliance with the MCLs may only be

conducted by certified laboratories. EPA

is requiring that analyses can be

conducted by a party acceptable to EPA

or the State in those situations where

the parameter can adequately be

measured by someone other than a

certified laboratory and for which there

is a good reason to allow analysis at

other locations (e.g., for samples which

normally deteriorate before reaching a

certified laboratory, especially when

taken at remote locations). For a

detailed discussion of the lab

certification requirements, see section

III.N.

I. Variances and Exemptions

Variances and exemptions will be

permitted in accordance with existing

statutory and regulatory authority. For a

detailed discussion see section III.M.

J. State Recordkeeping, Primacy, and

Reporting Requirements

The Stage 1 DBPR requires States to

adopt several regulatory requirements,

including public notification

requirements, MCLs for DBPs, MRDLs

for disinfectants, and the requirements

in Subpart L. In addition, States are

required to adopt several special

primacy requirements for the Stage 1

DPBR. States are also required to keep

specific records in accordance with

existing regulations and additional

records specific to the Stage 1 DBPR.

Finally, the rule does not require any
69398 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

State additional reporting requirements

beyond those required under existing

regulations. These requirements are

discussed in more detail in Section III.L.

K. System Reporting Requirements

System are required to report

monitoring data to the State as

discussed in Section III.K.

L. Guidance Manuals

EPA is developing guidance for both

systems and States for the

implementation of the Stage 1 DBPR

and the IESWTR. The guidance manuals

include: Guidance Manual for Enhanced

Coagulation and Precipitative Softening;

Disinfection Benchmark Guidance

Manual; Turbidity Guidance Manual;

Alternative Disinfectants and Oxidants

Guidance Manual; M/DBP Simultaneous

Compliance Manual; Sanitary Survey

Guidance Manual; Unfiltered Systems

Guidance Manual; and Uncovered

Finished Water Reservoirs. Guidance

manuals will be available after the

publication of the Stage 1 DBPR.

M. Regulation Review

Under the provisions of the SDWA

(Section 1412(b)(9)), the Agency is

required to review NPDWRs at least

once every six years. As mentioned

previously, today’s final rule revises,

updates, and supersedes the regulations

for total trihalomethanes, initially

published in 1979. Since that time,

there have been significant changes in

technology, treatment techniques, and

other regulatory controls that provide

for greater protection of human health.

As such, for today’s rule, EPA has

analyzed innovations and changes in

technology and treatment techniques

that have occurred since promulgation

of the interim TTHM regulations. That

analysis, contained primarily in the cost

and technology document supporting

this rule, supports the changes in the

Stage 1 DBPR from the 1979 TTHM rule.

EPA believes that the innovations and

changes in technology and treatment

techniques that result in changes to the

1979 TTHM regulations are feasible

within the meaning of SDWA Section

1412(b).

III. Explanation of Final Rule

A. MCLGs/MRDLGs

MCLGs are set at levels at which no

known or anticipated adverse health

effects occur, allowing for an adequate

margin of safety. Establishment of an

MCLG for each specific contaminant is

based on the available evidence of

carcinogenicity or noncancer adverse

health effects from drinking water

exposure using EPA’s guidelines for risk

assessment (see the proposed rule at 59

FR 38677 for a detailed discussion of

the process for establishing MCLGs).

The final Stage 1 DBPR contains

MCLGs for: four THMs (chloroform,

bromodichloromethane,

dibromochloromethane, and

bromoform); two haloacetic acids

(dichloroacetic acid and trichloroacetic

acid); bromate; and chlorite (see table

II–2 for final MCLG levels). These

MCLGs are the same as those proposed

in 1994 with the exception of chlorite,

which increased from 0.08 mg/L to 0.8

mg/L. The MCLG for chloral hydrate has

been dropped since EPA has concluded

that it will be controlled by the MCLs

for TTHM and HAA5 and the enhanced

coagulation treatment technique.

The final Stage 1 DBPR contains

MRDLGs for chlorine, chloramines and

chlorine dioxide (see table II–1 for final

MRDLG levels). The MRDLGs are as the

same as those proposed in 1994, with

the exception of chlorine dioxide,

which increased from 0.3 mg/L to 0.8

mg/L.

The MRDLG concept was introduced

in the proposed rule for disinfectants to

reflect the fact that these substances

have beneficial disinfection properties.

As with MCLGs, MRDLGs are

established at the level at which no

known or anticipated adverse effects on

the health of persons occur and which

allows an adequate margin of safety.

MRDLGs are nonenforceable health

goals based only on health effects and

exposure information and do not reflect

the benefit of the addition of the

chemical for control for waterborne

microbial contaminants. By using the

term ‘‘residual disinfectant’’ in lieu of

‘‘contaminant’’, EPA intends to avoid

situations in which treatment plant

operators are reluctant to apply

disinfectant dosages above the MRDLG

during short periods of time to control

for microbial risk.

EPA received numerous comments on

the use of the term MRDLG. The

majority of commenters agreed that the

term MRDLG was appropriate to use in

place of MCLG for disinfectants. Other

commenters agreed, but felt that the

language should more strongly reflect

that disinfectants are necessary and that

short-term exposure to elevated levels of

the disinfectants is not a health concern.

Some commenters suggested that

MRDLGs be extended to ozone,

potassium permanganate and iodine.

In response, EPA agrees with the

majority of commenters that the use of

the term MRDLG is appropriate and

therefore the final rule retains this term.

EPA believes the language on the

importance of disinfectants is adequate

in the rule and thus has not changed

this language. EPA does not agree that

the potential health effects from shortterm exposure to elevated levels of

disinfectants can be dismissed. Ozone

does not require an MRDLG because it

reacts so completely that it does not

occur in water delivered to consumers.

Finally, EPA believes the use of the

MRDLGs for other disinfectants or

oxidants would not be appropriate since

MRDLGs are developed for regulated

compounds controlled by MRDLs or

treatment techniques and EPA does not

allow these compounds to be used to

demonstrate compliance with

disinfection requirements.

The information EPA relied on to

establish the MCLGs and MRDLGs was

described in the 1994 proposal (EPA,

1994a), the 1997 DBP NODA (EPA,

1997b), and the 1998 NODA (EPA,

1998a). Criteria and assessment

documents to support the MCLGs and

MRDLGs are included in the docket

(EPA, 1993a; EPA, 1994 d–h; EPA,

1997c; EPA, 1998 b–f; and EPA, 1998p).

A summary of the occurrence and

exposure information for this rule are

detailed in ‘‘Occurrence Assessment for

Disinfectants and Disinfection

Byproducts in Public Drinking Water

Supplies’ (EPA, 1998u). The discussion

of the data used to establish the MCLGs

and MRDLGs and a summary of the

major public comments for these

chemicals are included below. A more

detailed discussion is included below

for chloroform, DCA, chlorite, chloride

dioxide, and bromate than the other

disinfectants and DBPs. This is the case

because significant new data has

become available since the 1994

proposal for these four DBPs and one

disinfectant.

1. MCLG for Chloroform

a. Today’s Rule. After careful

consideration of all public comments,

EPA has concluded at this time to

promulgate an MCLG for chloroform of

zero as proposed. This conclusion

reflects an interim risk-management

decision on the part of the Agency. The

Agency recognizes the strength of the

science in support of a non-linear

approach for estimating carcinogenicity

of chloroform. EPA received public

comments that questioned the

underlying basis and approach used to

reach the science judgment that the

mode of chloroform’s carcinogenic

action supports a nonlinear approach.

Equally important are the policy and

regulatory issues raised by stakeholders

that touch on this issue. EPA believes

that it is essential to pursue a further

dialogue with stakeholders on the issues

raised in the public comments before

applying the substantial new data and

science on the mode of carcinogenic
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69399

action discussed in the 1998 NODA to

the important decision of moving to a

non-linear cancer extrapolation

approach for drinking water

contaminants under the SDWA.

Moreover, EPA will complete additional

deliberations with the Agency’s Science

Advisory Board (SAB) (open to

stakeholder presentations to the SAB)

on the analytical approach used to

evaluate and reach conclusions on mode

of action data, and the science basis for

the mode of carcinogenic action for

chloroform.

In evaluating how to proceed in the

development of an MCLG for

chloroform, the Agency believes two

additional factors must be taken into

consideration. First, as part of the 1996

SDWA amendments, Congress

mandated that the Stage 1 DBPR rule be

promulgated by November 1998. EPA

has concluded that it would be

impossible to complete the additional

deliberations noted above in time to

meet this statutory deadline. Second, as

explained below, the Agency has also

completed analysis indicating that

regardless of whether the MCLG is

based on a low-dose linear or non-linear

extrapolation approach, the MCL

enforceable standard for TTHMs of 0.08

mg/L will not be affected. In light of

these issues, EPA believes it is

appropriate and consistent with the

public health goals of the SDWA to

establish a zero MCLG for chloroform

based on a linear default extrapolation

approach until the Agency is able to

complete additional deliberations with

the Agency’s SAB on the analytical

approach used to evaluate and reach

conclusions on mode of action data and

the science basis for the mode of

carcinogenic action for chloroform, and

complete the process of further public

dialogue on the important question of

moving to a non-linear cancer

extrapolation approach. EPA also notes

that its approach is consistent with

legislative history of the SDWA (see 56

FR 3533—EPA, 1991) and the 1996

SDWA Amendments.

b. Background and Analysis. As part

of its 1994 Stage 1 DBP proposal (EPA,

1994a), EPA requested comment on a

zero MCLG for chloroform. This was

consistent with information provided to

the 1992 Reg. Neg. Committee and was

based on data from a drinking water

study by Jorgensen et al. (1985)

indicating an increase of kidney tumors

in male rats in a dose-related manner.

However, at the time of the proposal

there was insufficient data to determine

the mode of carcinogenic action for

chloroform. Therefore, EPA based its

1994 proposal on a risk management

decision that a presumptive or low-dose

linear default (i.e, MCLG of zero) was

appropriate until more research became

available and there was an adequate

opportunity to work with stakeholders

and the scientific community to

evaluate and assess the technical as well

as policy and regulatory implications of

such new information. The 1994

proposal also reflected the Agency’s

1986 Guidelines for Carcinogen Risk

Assessment (EPA, 1986) which

recommended reliance on the default

assumption of low-dose linearity in the

absence of substantial information on

the mechanism of carcinogenicity.

Since the 1994 proposal, over 30

toxicological studies have been

published on chloroform. These studies

were discussed in the November 1997

Stage 1 DBP NODA (EPA, 1997b). In

addition, EPA published a second DBP

NODA in March 1998 (EPA, 1998a)

which discussed recommendations and

findings from a 1997 International Life

Sciences Institute project (ILSI, 1997),

co-sponsored by EPA, on the cancer

assessment for chloroform. The ILSI

project included the analysis and

conclusions from an expert panel which

was convened and charged with

reviewing the available database

relevant to the carcinogenicity of

chloroform, and considering how end

points related to mode of action can be

applied in hazard and dose-response

assessment by using guidance provided

by the EPA’s 1996 Proposed Guidelines

for Carcinogen Assessment (EPA,

1996b). The panel was made up of 10

internationally recognized scientists

from academia, industry, government,

and the private sector. Based on a

consideration of the ILSI panel findings

and an assessment of new data on

chloroform since 1994, EPA requested

comment in the 1998 NODA on the

Agency’s science conclusion that

chloroform is a likely human carcinogen

and that available scientific analysis

supports a non-linear mode of action for

estimating the carcinogenic risk

associated with lifetime exposure from

ingesting drinking water.

As part of the 1998 NODA, EPA also

requested comment on a revised

chloroform MCLG of 0.30 mg/L. The

revised MCLG was premised on the

substantial new science noted above

that supports a non-linear mode of

action. In calculating the specific

MCLG, EPA relied upon data relating to

hepatoxicity in dogs (EPA, 1994a). This

hepatoxicity endpoint was deemed

appropriate given that hepatic injury is

the primary effect following chloroform

exposure; and that an MCLG based on

protection against liver toxicity should

be protective against carcinogenicity

given that the putative mode of action

understanding for chloroform involves

cytotoxicity as a key event preceding

tumor development. The MCLG of 0.3

mg/L was calculated using a relative

source contribution (RSC) of 80 percent.

The RSC of 80 percent was based on the

assumption that most exposure to

chloroform is likely to come from

ingestion of drinking water. The 80

percent assumption for the RSC was

consistent with the calculations used to

derive the MCLGs for D/DBPs in the

1994 proposal. Based on information

received during the public comment

period for the 1998 NODA, EPA is

considering revising its estimate of the

RSC for chloroform as discussed below.

Since the 1998 NODA, EPA has

reevaluated elements of the analysis

underlying a revised MCLG of 0.30 mg/

L. Considering recent information not

fully analyzed as part of the 1998

NODA, the Agency is considering

revising the assumption of an 80% RSC

from ingestion of drinking water in view

of data which indicates that exposure to

chloroform via inhalation and dermal

exposure may potentially contribute a

substantial percentage of the overall

exposure to chloroform depending on

the activity patterns of individuals.

Also, EPA is in the process of

developing a policy for incorporating

inhalation and dermal exposure into the

derivation of the RSC. Furthermore,

there is considerable uncertainty

regarding the potential exposure to

chloroform via the dietary route and

there is information which indicates

individuals who are frequent swimmers

may receive a large amount of

chloroform during swimming. There are

additional uncertainties regarding other

possible highly exposed subpopulations, e.g., from use of

humidifiers, hot-tubs, and outdoor

misters. In conclusion, because there

may be a potential for exposure to

chloroform from other routes of

exposure than ingestion of drinking

water, EPA is considering using the 20

percent default floor to ensure adequate

public health protection. The 20 percent

has been used historically for drinking

water contaminants other than D/DBPs

when there is uncertainty in the

available exposure data. The use of the

20 percent RSC for chloroform would

produce a MCLG of 0.07 mg/L:
69400 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

MCLG for chloroform = 0.01 mg/kg/d 70 kg 0.2

2L/d mg

× × = 0 07 . /L

In addition to its reassessment of

technical assumptions underlying the

revised MCLG, the Agency has also

reviewed and carefully considered in

detail a number of significant comments

on the 1998 NODA. These comments

reflect both substantial scientific

support as well as significant concerns

with a possible MCLG of 0.30 mg/L. As

outlined in more detail below, a number

of nationally recognized scientific

experts strongly affirmed the data and

technical rationale for relying upon a

non-linear mode of action for

chloroform. Other commenters,

however, highlighted several scientific

issues they felt were not adequately

considered. These commenters also

emphasized their concern that the

policy, regulatory, and enforcement

implications related to a revised MCLG

were not raised by EPA in either the

1992 or the 1997 regulatory negotiation

processes leading up to today’s final

rule. Thus, these commenters felt that a

number of stakeholders who

recommended support for components

of the Stage 1 DBPR rule did so under

one set of conditions and assumptions

that the Agency subsequently changed

without providing a sufficient

opportunity for further debate and

discussion.

EPA believes that an adequate

opportunity for notice and comment

was provided as a result of the 1997 and

1998 DBP NODAs on the underlying

scientific data and technical issue of

moving to a non-linear extrapolation

approach based on an understanding of

the mode of carcinogenic action for

chloroform and recalculating the

chloroform MCLG to a nonzero number.

However, the Agency recognizes that

reliance on a non-linear mode of action

under the SDWA does represent a

significant and precedential, albeit

sound, application of new science to the

policy development and risk

management decision making process of

establishing appropriately protective

MCLGs. The Agency also recognizes

that although, as discussed below, a

revised MCLG for chloroform would not

affect the TTHM MCL under today’s

rule, the precedential decision to utilize

a non-linear cancer extrapolation

approach clearly has important

implications for the development of

future MCLGs where there is also

adequate scientific research and data to

support such a non-linear analysis.

In reviewing the range of scientific,

policy, and regulatory analyses and

strongly held views associated with

development of the chloroform MCLG,

EPA notes that the one question not

fundamentally at issue is the

establishment of the 0.080 mg/L TTHM

MCL. The majority of commenters who

addressed the proposed TTHM MCL

continue to support it. This is

particularly important to EPA in light of

congressional action with regard to the

M–DBP process in the 1996 SDWA

Amendments. In enacting the

Amendments and particularly in

expressing congressional intent in the

conference Report, Congress was careful

to emphasize ‘‘that the new provisions

of this conference agreement not

conflict with the parties’ agreement nor

disrupt the implementation of the

regulatory actions,’’ (such as the current

agreement on an TTHM MCL of 0.080

mg/L). Both of these important elements

of the Congressional intent were

reflected in the statutory text. Section

1412(b)(2)(C) requires EPA to maintain

the M–DBP rule staggered promulgation

strategy agreed to by the negotiated

rulemaking; and Section 1412(b)(6)(C)

exempted the future M–DBP rules from

the new cost-benefit standard-setting

provision (1412(b)(6)(A)) but not from

the new risk-risk provision (1412(b)(5)),

because the latter was a part of the

negotiated rulemaking agreement but

the former was not.

The Agency, itself, also believes that

the underlying logic, data, and rationale

supporting establishment of a TTHM of

0.080 mg/L MCL is compelling, and this

is a critical factor in the Agency’s

chloroform MCLG decision under

today’s rule. Under either a low-dose

linear or non-linear extrapolation to

derive the MCLG, the final TTHM MCL

remains unaffected.

After thorough review of the data and

comments, EPA believes the nonlinear

cancer extrapolation approach is the

most appropriate means to establish an

MCLG for chloroform based on

carcinogenic risk. However, in light of

its own reconsideration of the

appropriate RSC for chloroform under

such an approach, considering the range

of policy, regulatory, and enforcement

issues raised as part of the public

comment period, recognizing the

importance of deliberations with SAB

before proceeding further and, yet,

recognizing that this cannot be

accomplished within the constraints of

meeting the statutory deadline for Stage

1 DBPR rule of November 1998, EPA has

determined that on balance the more

appropriate and prudent risk

management decision at this time is to

establish an MCLG for chloroform at the

proposed presumptive default level of

zero. As part of this decision, the

Agency will complete additional

deliberations with the Agency’s SAB on

the analytical approach used to evaluate

and reach conclusions on mode of

action data, and the science basis for the

mode of carcinogenic action for

chloroform. The SAB’s review will be

factored into the Agency’s Stage 2 DBP

rulemaking process. EPA will also

include consideration of the regulatory,

policy, and precedential issues

involving chloroform in the Agency’s

Round 2 M–BP stakeholder process.

EPA wishes to make clear that its

interim decision in today’s rule to set an

MCLG of zero pending SAB review and

further stakeholder involvement is not

intended to prejudge the question of

what the appropriate MCLG should be

for purposes of regulatory decisions

under the Stage 2 DBPR. EPA may

decide to retain the zero MCLG for that

rule, or to revise it, depending on the

outcome of the SAB review, as well as

any new scientific evidence that may

become available. In regard to the

appropriate RSC factor, in case a nonlinear approach should ultimately be

adopted, the Agency requests that

stakeholders provide any data they man

have bearing on this determination.

The fundamental objective of the

SDWA is to establish protective public

health goals (MCLGs) together with

enforceable standards (MCLs or

treatment techniques) to move the water

treatment systems as close to the public

health goal as is technologically and

economically feasible. In the case of the

chloroform and TTHMs, this objective is

met with whichever extrapolation

approach (low dose linear versus

nonlinear) is relied upon.

c. Summary of Comments. EPA

received numerous comments on both

the 1994 proposed rule regarding the

MCLG of zero for chloroform and the

MCLG of 0.3 mg/L contained in the

1998 NODA. Some commenters were

supportive of the MCLG of zero, while

others were supportive of the 0.3 mg/L

MCLG. The major reason raised by

commenters for establishing a nonzero

MCLG (e.g., 0.3 mg/L) was that there

was convincing scientific evidence to

conclude that a nonlinear margin of

exposure approach for evaluating the

carcinogenic risk from chloroform is

warranted. Commenters who were
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69401

against establishing a nonzero MCLG for

chloroform presented policy and

scientific concerns. Scientific concerns

raised by commenters opposed to the

nonzero MCLG included their

perceptions that: there is insufficient

scientific evidence of a threshold for

chloroform; the threshold assumption is

also invalid because chloroform cooccurs with other mutagenic

carcinogens; EPA ignored human data

in establishing the MCLG for

chloroform; the linkage between

cytotoxicity and regenerative

proliferation and kidney tumors is not

supported by the data; and the evidence

for genotoxicity is mixed and it would

be difficult if not impossible to

conclude that the evidence demonstrate

chloroform has no direct effect on DNA.

As detailed at greater length in the

docket, EPA does not agree with these

comments as a technical matter. The

Agency does agree with the commenters

view that further discussion of these

issues with both the SAB and as part of

additional public dialogue is

appropriate.

The policy issues raised by

commenters included their belief that: a

zero MCLG is required to comply with

provisions of the SDWA; EPA is

required to use the 1986 Cancer

Guidelines (EPA, 1986) until the 1996

Cancer Guidelines (EPA, 1996b) are

formally finalized, and under the 1986

guidelines the MCLG for chloroform

must be set at zero; EPA did not provide

sufficient opportunity for the members

of the FACA, established to assist in the

development of the Stage 1 DBP rule, to

properly consider the potential

implications of a nonzero MCLG; and

setting a MCLG for chloroform (0.3 mg/

L) above the MCL for the TTHMs (0.08

mg/L) is illogical.

In response, EPA believes that the

underlying science for using a nonlinear

extrapolation approach to evaluate the

carcinogenic risk from chloroform is

well founded. As explained above,

because of the issues raised during the

public comment period, EPA believes

additional review and dialogue with

stakeholders is needed prior to

departing from a long-held EPA policy

of establishing zero MCLGs for known

or probable carcinogens. EPA will also

complete additional deliberations with

the Agency’s SAB on the analytical

approach used to evaluate and reach

conclusions on mode of action data, and

the science basis for the mode of

carcinogenic action for chloroform.

In response to the policy issues raised

by commenters, EPA, historically, has

established MCLGs of zero for known or

probable human carcinogens based on

the principle that any exposure to

carcinogens might represent some finite

level of risk and therefore an MCLG

above zero did not meet the statutory

requirement that the goal be set where

no known anticipated adverse effects

occur, allowing for an adequate margin

of safety (56 FR 3533; EPA, 1991).

However, if there is scientific evidence

that indicates there is a ‘‘safe threshold’’

then a non-zero MCLG could be

established with an adequate margin of

safety (56 FR 3533; EPA, 1991)). Even

though EPA, as an interim matter, is

establishing an MCLG of zero for

chloroform in today’s rule, it believes it

has the authority to establish nonzero

MCLGs for carcinogens if the scientific

evidence supports this finding.

In response to commenter’s concerns

with EPA using the proposed 1996

Guidelines for Carcinogen Risk

Assessment (EPA, 1996b) instead of the

Agency’s 1986 guidelines, EPA believes

it is important to point out that the 1986

guidelines provide for departures from

default assumptions such as low dose

linear assessment. For example, the

1986 EPA guidelines reflect the position

of the OSTP (1985; Principle 26) ‘‘No

single mathematical procedure is

recognized as the most appropriate for

low-dose extrapolation in

carcinogenesis. When relevant

biological evidence on mechanisms of

action exists (e.g, pharmacokinetics,

target organ dose), the models or

procedure employed should be

consistent with the evidence.’’ The 1986

guideline goes on to further state ‘‘The

Agency will review each assessment as

to the evidence on carcinogenesis

mechanisms and other biological or

statistical evidence that indicates the

suitability of a particular extrapolation

model.’’ The EPA’s 1996 Proposed

Guidelines for Carcinogen Risk

Assessment allow EPA to use other

default approaches to estimate cancer

risk than the historic, linearized

multistage default when there is an

understanding of an agent’s mode of

carcinogenic action. EPA believes that

reliance on the 1986 guidance allows

EPA to reach the same conclusion on

the carcinogenic risk from chloroform as

if the 1996 guidelines were used. The

use of the best available science is a core

EPA principle and is statutorily

mandated by the SDWA amendments of

1996. The 1996 Proposed Guidelines for

Carcinogen Risk Assessment reflect new

science and are consistent with the

existing 1986 Guidelines for Carcinogen

Risk Assessment. EPA considered the

1996 proposed guidelines in assessing

the health effects data for chloroform

and the other contaminants discussed in

the 1998 March NODA.

EPA agrees with commenters that

additional review by the FACA of the

regulatory implications of a nonlinear

approach is appropriate for policy

reasons, and will initiate these

discussions in the context of the Stage

2 DBPR FACA deliberations. In light of

the November 1998 statutory deadline

to promulgate the Stage 1 DBP rule and

the steps necessary to complete a final

rule, EPA has concluded that there is

not enough time to meet with the SAB

and FACA, provide ample opportunity

for debate, resolve differing points of

views, and complete additional analysis

to meet stakeholders policy concerns in

the context of the Stage 1 DBP rule. EPA

notes, however, that regardless of the

MCLG for chloroform, the MCL for the

THMs remains at 0.08 mg/L. Since the

MCL is the enforceable standard that

water systems will be required to meet,

a nonlinear or low dose linear

extrapolation to derive the MCLG will

not have a direct impact on the

compliance obligations of public water

systems or on the levels of chloroform

allowed in public water systems,

although it may be relevant to

development of enforceable regulatory

limits established under future rules.

2. MCLG for Bromodichloromethane

(BDCM)

a. Today’s Rule. The final MCLG for

BDCM is zero. The zero MCLG is based

on the classification of BDCM as a

probable human carcinogen. The MCLG

was determined in a weight-of-evidence

evaluation which considered all

relevant health data including

carcinogenicity and reproductive and

developmental toxicity animal data.

EPA believes the data are insufficient at

this time to determine the mode of

carcinogenic action for BDCM, and

therefore a low dose linear extrapolation

approach is used to estimate lifetime

cancer risk as a default.

b. Background and Analysis. In the

1994 Stage 1 DBPR proposal, the MCLG

of zero for BDCM was based on large

intestine and kidney tumor data from a

National Toxicology Program (NTP)

chronic animal study (NTP, 1987). Since

the proposal, several new studies have

been published on BDCM metabolism

(EPA, 1997c). In addition, several new

genotoxicity studies and short-term

toxicity studies including reproductive

evaluations were found for BDCM (EPA,

1997c). These new studies contribute to

the weight-of-evidence conclusions

reached in the 1994 proposal. Based on

this evidence, the final MCLG for BDCM

is zero based on sufficient evidence of

carcinogenicity in animals.

c. Summary of Comments. Several

commenters disagreed with the use of a
69402 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

corn oil gavage animal cancer study to

determine the MCLG for BDCM. Some

commenters agreed with the EPA

decision to use large intestine and

kidney tumor data from the corn oil

gavage study, but not liver tumor data

in the quantitative estimation of

carcinogenic risk. One commenter

agreed that a low-dose linear

extrapolation approach to dose-response

assessment was appropriate at this time

and consistent with EPA policy.

However, this commenter suggested that

EPA undertake chronic studies that

include a drinking water study of BDCM

and toxicokinetics. One commenter

disagreed with the EPA conclusion that

the evidence on the mutagenicity of

BDCM is adequate.

In response, EPA agrees with

commenters that a drinking water study

is preferable to a corn oil gavage study

to assess risk from DBPs in drinking

water. However, the NTP corn oil

gavage study is the best data available

on BDCM for a quantitative risk

estimation at this time. BDCM is

currently being tested for toxicokinetics

and cancer in a chronic BDCM drinking

water rodent study by the NTP. When

these data are available, EPA will

reassess the cancer risk of BDCM. EPA

believes that the animal data currently

available on BDCM are consistent with

EPA cancer guidelines on classifying

BDCM as a probable human carcinogen

given the evidence on mutagenicity and

given there was an increased incidence

of tumors at several sites in the animals.

Additionally, tumors were found in

both sexes of two rodent species.

Finally, there have been several new

studies on the genotoxicity of BDCM

that have supported a mutagenic

potential for BDCM (EPA, 1997c)

3. MCLG for Dibromochloromethane

(DBCM)

a. Today’s Rule. The final MCLG for

DBCM is 0.06 mg/L. This MCLG is

based on a weight of evidence

evaluation of the cancer and noncancer

data which resulted in the classification

of DBCM as a possible human

carcinogen.

b. Background and Analysis. In the

1994 proposal, the MCLG of 0.06 mg/L

for DBCM was based on observed liver

toxicity from a subchronic study and

possible carcinogenicity (NTP, 1985).

EPA is not aware of any new

information that would change its

evaluation of DBCM since the proposal.

The final MCLG is therefore 0.06 mg/L.

c. Summary of Comments. Several

commenters disagreed with the

additional safety factor of 10 to account

for possible carcinogenicity that was

used in the MCLG calculation. One

commenter agreed with EPA’s decision

to base the MCLG on noncarcinogenic

endpoints. Several commenters

disagreed with the use of a corn oil

gavage study to determine the MCLG for

DBCM.

In response, because the evidence of

carcinogenicity was limited on DBCM

(i.e., increased tumor response in only

one of the two species tested), EPA

classified DBCM as a possible human

carcinogen. The additional factor of 10

to account for possible carcinogenicity

follows EPA’s science policy for

establishing MCLGs (EPA, 1994a). EPA

used liver effects from the NTP

subchronic corn oil gavage study as the

basis for the Reference Dose (RfD). EPA

agrees with the comment that this is an

appropriate basis for deriving the RfD

for DBCM. EPA agrees with commenters

that a drinking water study is preferable

to a corn oil gavage study to assess risk

from DBPs in drinking water. However,

the NTP corn oil gavage study is the best

data available on DBCM for derivation

of the MCLG at this time. EPA does not

plan to conduct additional chronic

studies for DBCM but is conducting

additional toxicokinetics and short term

drinking water studies on DBCM to

better understand the potential risk

associated with exposure through

drinking water.

4. MCLG for Bromoform

a. Today’s Rule. The final MCLG for

bromoform is zero. The zero MCLG is

based on a weight-of-evidence

classification that bromoform is a

probable human carcinogen based on a

consideration of all relevant health data

including cancer and noncancer effects.

EPA believes the data are insufficient at

this time to determine the mode of

carcinogenic action for bromoform, and

therefore a low dose linear extrapolation

approach is used to estimate lifetime

cancer risk as a default.

b. Background and Analysis. The

proposed MCLG for bromoform was

zero. This MCLG was based on an NTP

chronic animal carcinogenicity study

(NTP, 1989). Since the proposal, new

studies on the genotoxicity of

bromoform were found. However, these

new studies do not support changing

the proposed MCLG of zero for

bromoform. The final MCLG for

bromoform is therefore zero.

c. Summary of Comments. Several

commenters agreed with EPA’s

classification for bromoform as a

probable carcinogen. Other commenters

disagreed with this classification stating

that there was insufficient evidence

available because tumors were found in

only one species and the increased

number of tumors was small. These

commenters generally felt that EPA

should use an RfD approach in

quantifying the risk for bromoform.

Some commenters encouraged EPA to

conduct more experiments on

bromoform toxicity. Some commenters

were concerned with the use of a corn

oil gavage study to determine

carcinogenic risk.

In response, although the increase in

tumors was small, the increase was

considered significant because large

intestine tumors in both male and

female rats are rare and thus provides

sufficient evidence to classify

bromoform as a probable human

carcinogen. EPA does not plan on

conducting additional chronic testing

for bromoform at this time, but is

conducting toxicokinetic studies and

shorter term drinking water studies to

better understand the potential risk

associated with exposure to bromoform

in drinking water. EPA agrees with

commenters that drinking water studies

are preferable to a corn oil gavage study

to assess risk from DBPs in drinking

water. However, the NTP corn oil

gavage study is the best data available

on bromoform for derivation of the

MCLG.

5. MCLG for Dichloroacetic Acid (DCA)

a. Today’s Rule. The final MCLG for

DCA is zero. EPA has developed a

weight-of-evidence characterization for

DCA in which it evaluated all relevant

health data (both cancer and noncancer

effects). The MCLG of zero is based on

sufficient evidence of carcinogenicity in

animals which indicates that DCA is a

probable human carcinogen (likely

under proposed cancer guidelines). EPA

believes the data are insufficient at this

time to determine the mode of

carcinogenic action for DCA and that

the data is insufficient to quantify the

potential cancer risk from DCA.

b. Background and Analysis. EPA

proposed an MCLG of zero for DCA.

This was based on classifying DCA as a

probable human carcinogen in

accordance with the 1986 EPA

Guidelines for Carcinogen Risk

Assessment (EPA, 1986). The DCA

categorization was based primarily on

findings of liver tumors in rats and

mice, which was regarded as

‘‘sufficient’’ evidence in animals. No

lifetime risk calculation was conducted

at the time of the proposal because there

was insufficient data to quantify the risk

(EPA, 1994a).

As pointed out in the 1997 and 1998

DBP NODAs, several toxicological

studies have been identified for DCA

since the 1994 proposal (EPA, 1997c). In

addition, EPA co-sponsored an ILSI

project in which an expert panel was
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69403

convened to explore the application of

the EPA’s 1996 Proposed Guidelines for

Carcinogen Risk Assessment (EPA,

1996b) to the available data on the

potential carcinogenicity of chloroform

and DCA. The panel considered data on

DCA which included chronic rodent

bioassay data and information on

mutagenicity, tissue toxicity,

toxicokinetics, and other mode of action

information. The panel concluded that

the potential human carcinogenicity of

DCA ‘‘cannot be determined’’ primarily

because of the lack of adequate rodent

bioassay data (ILSI, 1997).

EPA prepared a new hazard

characterization regarding the potential

carcinogenicity of DCA in humans

(EPA, 1998b). One objective of this

report was to develop a weight-ofevidence characterization using the

principles of the EPA’s 1996 Proposed

Guidelines for Carcinogen Risk

Assessment (EPA, 1996b) which are

consistent with the 1986 Guidelines.

Another objective of the report was to

consider new data since the 1994

proposal and to address the issues

raised by the 1997 ILSI panel report.

EPA agreed with the ILSI panel report

that the mode of action through which

DCA induces liver tumors in both rats

and mice cannot be reasonably

determined at this time. EPA disagrees

with the ILSI panel that the potential

human carcinogenicity cannot be

determined. Based on the

hepatocarcinogenic effects of DCA in

both rats and mice in multiple studies,

as well as other date, for example,

showing that DCA alters cell replication

and gene expression, EPA concludes

that DCA should be considered as a

‘‘likely’’ (probable) cancer hazard to

humans (EPA, 1998b). Therefore, as in

the 1994 proposed rule, EPA believes

that the MCLG for DCA should remain

zero to assure public health protection.

c. Summary of Comments. Some

commenters agreed with the zero MCLG

for DCA based on positive carcinogenic

findings in two animal species. Several

commenters stated that a zero MCLG

was inappropriate due to evidence

which indicates a nongenotoxic mode of

action for DCA. The comment was

raised that the animal evidence was

insufficient to consider DCA a likely

(probable) human carcinogen, and that

DCA should be considered at most

suggestive of carcinogenicity.

In response, EPA concludes that DCA

should be considered as a probable

(likely under the 1996 proposed

guidelines) cancer hazard to humans

(EPA, 1998b) based on the

hepatocarcinogenic effects of DCA in

both rats and mice in multiple studies,

and mode of action related effects (e.g.,

mutational spectra in oncogenes,

elevated serum glucocorticoid levels,

alterations in cell replication and

death). EPA considers the mode of

action through which DCA induces liver

tumors in both rats and mice to be

unclear, and thus the likelihood of

human hazard associated with low

levels of DCA usually encountered in

the environment or in drinking water is

not sufficiently understood. EPA

acknowledges that a mutagenic

mechanism (i.e., direct DNA reactivity)

may not be an important influence on

the carcinogenic process at low doses.

EPA believes that the lack of

mutagenicity is not a sufficient basis to

depart from a low dose linear default

extrapolation approach for the cancer

assessment. There must be other

convincing evidence to explain how the

tumors are caused by the chemical. The

commenters have not presented such

evidence. Although DCA tumor effects

are associated with high doses used in

the rodent bioassays, there is

uncertainty regarding whether the mode

of tumorgenesis is solely through

mechanisms that are operative only at

high doses. Therefore, as in the 1994

proposed rule, EPA believes that the

MCLG for DCA should remain as zero to

assure public health protection. NTP is

implementing a new two year rodent

bioassay that will include full

histopathology at lower doses than

those previously studied. Additionally,

studies on the mode of carcinogenic

action are being done by various

investigators including the EPA health

research laboratory.

6. MCLG for Trichloroacetic Acid (TCA)

a. Today’s Rule. The final MCLG for

TCA is 0.3 mg/L, as was proposed in

1994. This MCLG is based on

developmental toxicity and limited

evidence of carcinogenicity in animals.

b. Background and Analysis. The

1994 proposed rule included a MCLG of

0.3 mg/L for TCA based on

developmental toxicity and possible

carcinogenicity based on limited

evidence in animal studies (i.e.,

hepatocarcinogenicity in mice). Since

the proposal, a 2-year carcinogenicity

study on TCA (DeAngelo et al., 1997)

found that TCA was not carcinogenic in

male rats. As was discussed in the 1997

DBP NODA (EPA, 1997b), there have

also been several recent studies

examining the mode of carcinogenic

action for TCA. These new studies

suggest that TCA does not operate via

mutagenic mechanisms. For a more in

depth discussion of this new data refer

to the 1997 DBP NODA (EPA, 1997b)

and related support documents (EPA,

1997c). This new information does not

alter the original assessment of the

health effects of TCA based on

developmental toxicity and limited

evidence of carcinogenicity. Therefore,

the MCLG will remain 0.3 mg/L.

c. Summary of Comments. Several

commenters agreed with the

classification of TCA as a possible

human carcinogen. One commenter felt

that toxicity data on TCA indicated a

threshold. Some commenters disagreed

with the study selected for estimating

the RfD (Smith et al. 1989). Some

commenters stated the uncertainty

factors used to establish the RfD were

too high.

In response, EPA acknowledges that a

DNA reactive mutagenic mechanism

may not be involved in TCA’s mode of

carcinogenicity. Because an RfD was

used in lieu of a quantitative cancer

assessment for establishing the MCLG,

however, there was no need to evaluate

the mode of carcinogenic action for TCA

at this time. EPA believes that the Smith

et al. (1989) study is appropriate to use

in quantifying risk from TCA since

developmental toxicity was the most

critical effect. EPA believes that an

uncertainty factor of 3,000 is

appropriate to account for inter and

intraspecies differences (100), a lowest

observed adverse effects level (LOAEL)

(10), and lack of a two-generation

reproductive study (3) (EPA, 1994a).

These uncertainty factors are consistent

with current Agency science policy on

using uncertainty factors (EPA, 1994a).

7. MCLG for Chlorite and MRDLG for

Chlorine Dioxide

a. Today’s Rule. The final MCLG for

chlorite is 0.8 mg/L and the final

MRDLG for chlorine dioxide is 0.8 mg/

L. The MCLG for chlorite was increased

from the proposed value of 0.08 mg/L to

0.8 mg/L based on a weight-of-evidence

evaluation of all health data on chlorite

including a recent two-generation

reproductive rat study sponsored by the

Chemical Manufactures Association

(CMA, 1996). The MRDLG for chlorine

dioxide was increased from the

proposed value of 0.3 mg/L to 0.8 mg/

L based on a weight-of-evidence

evaluation using all the health data on

chlorine dioxide including the

information on chlorite from the CMA

study. EPA believes that data on chlorite

are relevant to assessing the risks of

chlorine dioxide because chlorine

dioxide is rapidly reduced to chlorite.

Therefore, the findings from the CMA

study and previously described studies

in the 1994 proposal were used to assess

the risk for both chlorite and chlorine

dioxide.

b. Background and Analysis. The

1994 proposal included an MCLG of
69404 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

0.08 mg/L for chlorite. The proposed

MCLG was based on an RfD of 3 mg/kg/

d estimated from a lowest-observedadverse-effect-level (LOAEL) for

neurodevelopmental effects identified

in a rat study by Mobley et al. (1990).

This determination was based on a

weight of evidence evaluation of all the

available data at that time (EPA, 1994d).

An uncertainty factor of 1000 was used

to account for inter-and intra-species

differences in response to toxicity (a

factor of 100) and to account for use of

a LOAEL (a factor of 10).

The 1994 proposal included an

MRDLG of 0.3 mg/L for chlorine

dioxide. The proposed MRDLG was

based on a RfD of 3 mg/kg/d estimated

from a no-observed-adverse-effect-level

(NOAEL) for developmental

neurotoxicity identified from a rat study

(Orme et al., 1985; EPA, 1994d). This

determination was based on a weight of

evidence evaluation of all available

health data at that time (EPA, 1994a).

An uncertainty factor of 300 was

applied that was composed of a factor

of 100 to account for inter-and intraspecies differences in response to

toxicity and a factor of 3 for lack of a

two-generation reproductive study

necessary to evaluate potential toxicity

associated with lifetime exposure. To

fill this important data gap, the CMA

sponsored a two-generation

reproductive study in rats (CMA, 1996).

As described in more detail in the

1998 NODA (EPA, 1998a), EPA

reviewed the CMA study and completed

an external peer review of the study

(EPA, 1997d). In addition, EPA

reassessed the noncancer health risk for

chlorite and chlorine dioxide

considering the new CMA study (EPA,

1998d). This reassessment was also peer

reviewed (EPA, 1998d). Based on this

reassessment, EPA requested comment

in the 1998 NODA (EPA, 1998a) on

changing the proposed MCLG for

chlorite from 0.08 mg/L to 0.8 mg/L

based on the NOAEL identified from the

new CMA study which reinforced the

concern for neurodevelopmental effects

associated with short-term exposures.

EPA determined that the NOAEL for

chlorite should be 35 ppm (3 mg/kg/d

chlorite ion, rounded) based on a

weight-of-evidence approach. The data

considered to support the NOAEL are

summarized in EPA (1998d) and

included the CMA study as well as

previous reports on developmental

neurotoxicity and other adverse health

effects (EPA, 1998d). EPA continues to

believe, as stated in the 1998 NODA

(EPA, 1998a), that the RfD for chlorite

should be 0.03 mg/kg/d (NOAEL of 3

mg/kg/d with an uncertainty factor of

100) and that a MCLG of 0.8 mg/L is

appropriate. EPA has concluded that the

RfD for chlorine dioxide should be 0.03

mg/L (NOAEL of 3 mg/kg/d with an

uncertainty factor of 100) and that a

MRDLG of 0.8 mg/L is appropriate.

c. Summary of Comments. EPA

received numerous comments on the

1994 proposal (EPA, 1994a) and 1998

NODA (EPA, 1998a). The major

comment from the 1994 proposal was

that reliance on the Mobley et al. (1990)

study for the MCLG for chlorite and the

Orme et al. (1985) study for chlorine

dioxide were inappropriate and that the

results from the CMA study must be

evaluated before any conclusions on the

MCLG for chlorite or chlorine dioxide

could be drawn. In relation to the 1998

NODA, several commenters supported

changing the MCLG for chlorite and

MRDLG for chlorine dioxide while

others were concerned that the science

did not warrant a change in these

values. The major comments submitted

against raising the MCLG and MRDLG

focused on several issues. First, one

commenter argued that the 1000-fold

uncertainty factor used for chlorite in

the proposal should remain in place

because the CMA study used to reduce

the uncertainty factor was flawed.

Second, several commenters indicated

that the LOAEL should be set at the

lowest dose level (35 ppm) because

certain effects at the lowest dose tested

may have been missed. Finally, some

commenters argued that an additional

safety factor should be included to

protect children and drinking water

consumption relative to the body weight

of children should be used instead of

the default assumption of 2 L per day

and 70 kg adult body weight.

EPA agrees with commenters on the

1994 proposal that the results from the

CMA should be factored into any final

decision on the MCLG for chlorite and

chlorine dioxide. As explained in more

detail in the 1998 DBP NODA (EPA,

1998a), EPA considered the findings

from the CMA study along with other

available data to reach its conclusions

regarding the MCLG and MRDLG for

chlorite and chlorine dioxide.

EPA disagrees with the commenter

who suggested that the 1000-fold

uncertainty factor for chlorite should

remain because the CMA study was

flawed. The study design for the

neurodevelopmental component of the

CMA study was in accordance with

EPA’s testing guidelines at the time the

study was initiated. EPA had previously

reviewed the study protocol for the

CMA neurotoxicity component and had

approved the approach. While EPA

initially had some questions regarding

the design of the neurodevelopmental

component of the study (Moser, 1997),

subsequent information submitted by

the CMA provided clarification on

certain aspects of the study design

(CMA, 1998). EPA agrees that even with

the clarifications that there are some

limitations with the

neurodevelopmental component of the

CMA study. EPA believes that the

neuropathology components of the CMA

study were adequate. The functional

operation battery had some

shortcomings in that forelimb and

hindlimb grip strength and foot splay

were not evaluated. EPA believes the

results from the motor activity

component of the CMA study were

difficult to interpret because of the high

variability in controls. However, in its

evaluation of the MCLG for chlorite and

chlorine dioxide, EPA did not rely

solely on the CMA study, but used a

weight-of-evidence approach that

included consideration of several

studies. Thus, the shortcomings of one

study are offset by the weight from other

studies. EPA believes that the CMA

study contributes to the weight-of theevidence. The studies by Orme et al.

(1985), Mobley et al. (1990), and CMA

(1996) support a NOAEL of 3 mg/kg/d

based on neurodevelopmental effects

(e.g., decreased exploratory, locomotor

behavior, decreased brain weight).

Furthermore, the CMA study was

reviewed by outside scientists as well as

by EPA scientists. EPA’s re-assessment

for chlorite and chlorine dioxide

presented in the 1998 March NODA was

reviewed internally and externally in

accordance with EPA peer-review

policy. The three outside experts who

reviewed the Agency’s assessment

agreed with the NOAEL of 3 mg/kg/day

and the derived RfD.

Finally, EPA disagrees that an

additional safety factor should be

applied to provide additional protection

for children or that drinking water

consumption relative to the body weight

of children should be used in

developing the MCLG. The MCLG and

MRDLG presented for chlorite and

chlorine dioxide are considered to be

protective of susceptible groups,

including children, given that the RfD is

based on a NOAEL derived from

developmental testing, which includes a

two-generation reproductive study. A

two-generation reproductive study

evaluates the effects of chemicals on the

entire developmental and reproductive

life of the organism. Additionally,

current methods for developing RfDs are

designed to be protective for sensitive

populations. In the case of chlorite and

chlorine dioxide a factor of 10 was used

to account for variability between the

average human response and the
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69405

response of more sensitive individuals.

In addition, the important exposure is

that of the pregnant and lactating female

and the nursing pup. The 2 liter per day

water consumption and the 70 kg body

weight assumptions are viewed as

adequately protective of all groups.

Based on a review of all the data and

public comments, EPA believes that the

MCLG for chlorite should be 0.8 mg/L

and the MRDLG for chlorine dioxide

should be 0.8 mg/L. EPA believes the

MCLG and MRDLG are consistent with

the discussions during the regulatory

negotiations which recognized the need

for an acceptable two-generation

reproductive study prior to reducing the

uncertainty factors for chlorite and

chlorine dioxide. EPA believes the CMA

provided an acceptable two-generation

study with which to reduce the

uncertainty factors. In addition, EPA

believes potential health concerns in the

proposal with having a MCLG for

chlorite significantly below the MCL are

no longer relevant because the MCL for

chlorite in today’s rule will remain at

1.0 mg/L while the MCLG has been

revised to 0.8 mg/L. Given the margin of

safety that is factored into the

estimation of the MCLG of 0.8 mg/L,

EPA believes that the MCL of 1.0 mg/

L will be protective of public health of

all groups, including fetuses and

children.

The MCLG for chlorite is based on an

RfD of 0.03 mg/kg/d using a NOAEL of

3 mg/kg/d and an uncertainty factor of

100 to account for inter- and intraspecies differences. The MCLG for

chlorite is calculated to be 0.8 mg/L by

assuming an adult tap water

consumption of 2 L per day for a 70 kg

adult and using a relative source

contribution of 80% (because most

exposure to chlorite is likely to come

from ingestion of drinking water—

EPA,1998u). A more detailed discussion

of this assessment is included in the

public docket for this rule (EPA, 1998d).

MCLG for chlorite = 0.03 mg/kg/d 70 kg 0.8

2L/day mg

MCLG for chlorite = 0.8 mg/L (Rounded)

× × = 0 84 . /L

For chlorine dioxide the MCLG is

based on a NOAEL of 3 mg/kg/d and

applying an uncertainty factor of 100 to

account for inter-and intra-species

differences in response to toxicity, the

revised MRDLG for chlorine dioxide is

calculated to be 0.8 mg/L. This MRDLG

takes into account an adult tap water

consumption of 2 L per day for a 70 kg

adult and applies a relative source

contribution of 80% (because most

exposure to chlorine dioxide is likely to

come from ingestion of drinking water—

EPA, 1998u). A more detailed

discussion of this assessment is

included in the public docket for this

rule (EPA, 1998d).

MRDLG for chlorine dioxide = 0.03 mg/kg/d 70 kg 0.8

2L/day mg

MRDLG for chlorine dioxide = 0.8 mg/L (Rounded)

× × = 0 84 . /L

8. MCLG for Bromate

a. Today’s Rule. The final MCLG for

bromate is zero. The zero MCLG is

based on a weight-of-evidence

evaluation of both the cancer and

noncancer effects which indicates there

is sufficient laboratory animal data to

conclude that bromate is a probable

(likely under the 1996 proposed cancer

guidelines) human carcinogen. EPA

believes the data are insufficient at this

time to determine the mode of

carcinogenic action for bromate, and

therefore a low dose linear extrapolation

approach is used to estimate lifetime

cancer risk as a default.

b. Background and Analysis. The

1994 proposed rule included a MCLG of

zero for bromate based on a

determination that bromate was a

probable human carcinogen. This

determination was based on results from

a two species rodent bioassay by

Kurokawa et al. (1986a and 1986b) that

found kidney tumors in rats. Since the

1994 proposed rule, EPA has completed

and analyzed a new chronic cancer

study in male rats and mice for

potassium bromate (DeAngelo et al.,

1998). EPA reassessed the cancer risk

associated with bromate exposure (EPA,

1998e), had this reassessment peer

reviewed (EPA, 1998e), and presented

its findings in the March 1998 NODA

(EPA, 1998a). The new rodent cancer

study by DeAngelo et al. (1998)

contributes to the weight of the

evidence for the potential human

carcinogenicity of potassium bromate

and confirms the study by Kurokawa et

al. (1986 a,b).

c. Summary of Comments. Several

commenters supported the zero MCLG

for bromate. Others believed the MCLG

of zero was not justified because there

is evidence of a carcinogenic threshold.

This evidence indicates that bromate

causes DNA damage indirectly via lipid

peroxidation, which generates oxygen

radicals which in turn induce DNA

damage. Other commenters argued that

even if there is no carcinogenic

threshold, EPA has overstated the

potency of bromate by using the

linearized multistage model and should

instead use the Gaylor-Kodell model.

In response, EPA disagrees with

commenters who believed that the zero

MCLG was inappropriate. At this time,

under the principles of both the 1986

EPA Guidelines for Carcinogen Risk

Assessment (EPA, 1986) and the draft

1996 EPA Proposed Guidelines for

Carcinogen Risk Assessment (EPA,

1996b) weight-of-evidence approach,

bromate is considered to be a probable

or likely human carcinogen. This weight

of evidence conclusion of potential

human carcinogenicity is based on

sufficient experimental findings that

include the following: tumors at

multiple sites in rats; tumor responses

in both sexes; and evidence for

mutagenicity including point mutations

and chromosomal aberrations in in vitro

genotoxicity assays. Furthermore, EPA

believes there is insufficient evidence at

this time to draw conclusions regarding

the mode of carcinogenic action for

bromate. EPA acknowledges there are

studies available showing that bromate

may generate oxygen radicals which

increase lipid peroxidation and damage

DNA. However, no data are available

that link this proposed mechanism to

tumor induction. Thus, EPA believes

that while there are studies which

provide some evidence to support the

commenters’ claims, these studies are

insufficient at this time to establish
69406 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

lipid peroxidation and free radical

production as key events responsible for

the induction of the multiple tumor

responses seen in the bromate rodent

bioassays (EPA, 1998e). Given the

uncertainty about the mode of

carcinogenic action for bromate, EPA

believes it is appropriate to use the

default assumption of low dose linearity

to estimate the cancer risk and establish

the MCLG of zero for bromate. EPA is

conducting additional studies

investigating the mode of action for

bromate.

EPA also disagrees with commenters

who suggested that the Gaylor-Kodell

model should be used for low-dose

extrapolation of the bromate data. In the

1998 NODA, a low dose linear

extrapolation of the DeAngelo et al.

(1998) data was conducted using a onestage Weibull time-to-tumor model. The

Weibull model was considered to be the

preferred approach to account for the

reduction in animals at risk that may be

due to the decreased survival observed

in the high dose group toward the end

of the study. The estimate of cancer risk

from the DeAngelo et al. (1998) study is

similar with the risk estimate derived

from the Kurokawa et al. (1986a) study

presented in the 1994 proposed rule.

Based on an evaluation of all the data

and after review and consideration of

the public comments, EPA believes the

MCLG for bromate should be zero.

9. MCLG for Chloral Hydrate

a. Today’s Rule. EPA has decided to

not include an MCLG for chloral

hydrate in the Stage 1 DBPR. This

decision is based on an analysis of the

technical comments and on the fact that

chloral hydrate will be controlled by the

MCLs for TTHM and HAAs and by the

treatment technique of enhanced

coagulation.

b. Background and Analysis. The

1994 proposed rule included an MCLG

for chloral hydrate of 0.04 mg/L. This

was based on a 90-day mice study by

Sanders et al. (1982) which reported

liver toxicity. A RfD of 0.0016 mg/kg/d

was used (LOAEL of 16 mg/kg/d with an

uncertainty factor of 10,000). In the

1997 DBP NODA (EPA,1997b) and

supporting documents (EPA, 1997c),

additional studies on chloral hydrate

were discussed, however, these new

studies did not indicate a change in the

MCLG for chloral hydrate.

c. Summary of Comments. The

majority of commenters disagreed with

the MCLG of 0.04 mg/L for chloral

hydrate. Several commenters questioned

the need for an MCLG for chloral

hydrate. These commenters mentioned

its low toxic potential and the fact that

safe concentrations of chloral hydrate

are substantially greater than those

present in drinking water. Commenters

also questioned the need for an MCLG

for chloral hydrate because the MCLs for

THMs and HAAs and the treatment

technique of enhanced coagulation will

adequately control for chloral hydrate

and because there were no monitoring

provisions proposed. Other commenters

argued that the use of a 10,000

uncertainty factor and the selection of

the Sanders et al. (1982) study as a basis

for setting the MCLG were

inappropriate.

In response, EPA agrees with

commenters that an MCLG for chloral

hydrate is not needed. This is based on

the fact that the TTHM and HAA MCLs

and the treatment technique (i.e.,

enhanced coagulation/softening) will

control for chloral hydrate, as well as

other chlorination byproducts. In

addition, chloral hydrate does not serve

as an important indicator for other

chlorination byproducts. The final rule,

therefore, does not contain an MCLG for

chloral hydrate. In light of this decision,

EPA is not responding to comments on

the uncertainty factor used as the basis

for setting the MCLG.

10. MRDLG for Chlorine

a. Today’s Rule. EPA is promulgating

an MRDLG of 4 mg/L for chlorine based

on a NOAEL from a chronic study in

animals.

b. Background and Analysis. EPA

proposed an MRDLG of 4 mg/L for

chlorine. The MRDLG was based on a

two-year rodent drinking water study in

which chlorine was given to rats at

doses ranging from 4 to 14 mg/kg/day

and mice at doses ranging from 8 to 24

mg/kg/day (NTP, 1990). Neither

systemic toxicity, nor effects on body

weight and survival were found. Thus,

the MRDLG was based on a NOAEL of

14 mg/kg/day and application of a 100

fold uncertainty factor to account for

inter- and intra-species differences

(EPA, 1994a). New information on

chlorine has become available since the

1994 proposal and was discussed in the

1997 DBP NODA and is included in the

public docket (EPA, 1997c). This new

information did not contain data that

would change the MRDLG. EPA has

therefore decided to finalize the

proposed MRDLG of 4 mg/L for

chlorine.

c. Summary of Comments. Several

commenters agreed with EPA’s

conclusion that there is no animal

evidence of carcinogenicity for chlorine.

Some commenters also agreed with EPA

that 4 mg/L was the appropriate MCLG.

Several commenters agreed with the

proposed relative source contribution of

80 percent for chlorine. Some

commenters agreed with the uncertainty

factor of 100 while others felt that it was

too high. Some commenters encouraged

EPA to consider children in estimating

risk from chlorine.

In response, EPA believes that an

uncertainty factor of 100 is appropriate

when a NOAEL from a chronic animal

study is the basis for the RfD. Because

current methods for developing RfDs are

designed to be protective for sensitive

subpopulations, the uncertainty factor

of 100 is considered protective of

children. Furthermore, animal studies

indicate that chlorine is not a

developmental toxicant.

11. MRDLG for Chloramine

a. Today’s Rule. EPA is promulgating

an MRDLG of 4 mg/L for chloramines

based on a NOAEL from a chronic

rodent study.

b. Background and Analysis. The

1994 proposed Stage I DBPR included

an MRDLG for chloramines at 4 mg/L

based on a NOAEL of 9.5 mg/kg/d for

lack of toxicity in chronic rodent

drinking water study and on application

of an uncertainty factor of 100 to

account of inter- and intra-species

differences (EPA, 1994h). New

information on chloramines has become

available since the 1994 proposal and

was included in the 1997 DBP NODA

and is included in the public docket

(EPA, 1997c). This new information did

not contain data that would change the

MRDLG. EPA has therefore decided to

finalized the proposed MRDLG of 4 mg/

L for chloramines.

c. Summary of Comments. Several

commenters agreed with the MRDLG of

4 mg/L for chloramine (as chlorine).

Some commenters felt that the MRDLG

was too low due to conservative

uncertainty factors. Many commenters

agreed with EPA’s conclusion that there

is no animal evidence of carcinogenicity

for chloramines. Many commenters

agreed with the RSC of 80% for

chloramine while other believed that

the RSC should be higher.

In response, EPA believes that the

uncertainty factor of 100 in the MRDLG

calculation is appropriate to protect

public health including that of children

and sensitive subpopulations. EPA

believes that the 80 percent is an

appropriate ceiling for the RSC due to

lack of exposure data on other sources

of exposure.

B. Epidemiology

1. Cancer Epidemiology

a. Today’s Rule. EPA has evaluated all

of the cancer epidemiology data and the

corresponding public comments

received on the 1994 proposal (EPA,
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69407

1994a), 1997 NODA (EPA, 1997b), and

1998 NODA (EPA, 1998a). Based on this

evaluation, EPA believes that the cancer

epidemiology data provides important

information that contributes to the

weight-of-evidence evaluation on the

potential health risks from exposure to

chlorinated drinking water. At this time,

however, the cancer epidemiology

studies are insufficient to establish a

causal relationship between exposure to

chlorinated drinking water and cancer;

and are thus considered limited for use

in quantitative risk assessment. EPA’s

weight-of-evidence evaluation of the

potential risk posed by chlorinated

drinking water is further discussed in

section IV of this preamble.

b. Background and Analysis. The

preamble to the 1994 proposed rule

discussed numerous cancer

epidemiology studies that had been

conducted over the past 20 years to

examine the relationship between

exposure to chlorinated water and

cancer (EPA, 1994a). At the time of the

regulatory negotiation, there was

disagreement among the members of the

Reg. Neg. Committee on the conclusions

that could be drawn from these studies.

Some members of the Committee felt

that the cancer epidemiology data, taken

in conjunction with the results from

toxicological studies, provide ample and

sufficient weight-of-evidence to

conclude that exposure to DBPs in

drinking water could result in increased

cancer risk at levels encountered in

some public water supplies. Other

members of the Committee concluded

that the cancer epidemiology studies on

the consumption of chlorinated

drinking water to date were insufficient

to provide definitive information for the

regulation.

In the 1998 DBP NODA (EPA, 1998a),

EPA discussed several new

epidemiology studies that had been

published since the 1994 proposal. EPA

concluded in the 1998 NODA, based on

a review of all the cancer epidemiology

studies (including the more recent

studies), that a causal relationship

between exposure to chlorinated surface

water and cancer has not yet been

demonstrated. However, several studies

have suggested a weak association in

various subgroups. Results from recent

epidemiology studies continue to

support the decision to pursue

regulations to provide additional DBP

control measures as discussed in section

IV.D of this preamble.

c. Summary of Comments. Several

commenters agreed with EPA’s

characterization that there was

insufficient evidence to conclude that

there was a causal relationship between

exposure to chlorinated surface water

and cancer. Other commenters

disagreed with this characterization

stating that they believed the evidence

did indicate there was a strong

association between exposure to

chlorinated water and cancer. Other

commenters stated that EPA had not

clearly articulated the basis for its

conclusions on the issue of causality.

In response, EPA continues to believe

that there is insufficient evidence, based

on the epidemiology data, to conclude

there is a causal association between

exposure to chlorinated waters and

cancer. EPA agrees, however, that the

basis for its conclusion on causality was

not clearly articulated. This judgement

of causality was based on evaluating the

existing cancer epidemiologic database

for the following criteria: strength of

association, consistency of the findings,

specificity of the association, as well as

other information concerning the

temporal sequence and presence of a

dose-response relationship, and

biological plausibility (Federal Focus,

1996; EPA, 1986; EPA 1996b).

EPA applied the criteria stated above

to assess the possible causality of cancer

using the best available cancer

epidemiology studies (Cantor et al.,

1985, McGeehin et al., 1993, King and

Marrett, 1996, Cantor et al., 1998,

Freedman et al., 1997, Hildesheim et al.,

1998, Doyle et al., 1997). These studies

found a weak association for bladder

cancer, although the findings were not

consistent within and among the

studies. The specificity of the

association, temporal association, and

dose response relationship remain

unknown. In addition, the biological

mode of action has not been

determined. Using the criteria for

causality, the present epidemiologic

data do not support a causal

relationship between exposure to

chlorinated drinking water and

development of cancer at this time. This

conclusion does not preclude the

possibility that a causal link may be

established at a later date by future

epidemiology and toxicology studies.

Some commenters argued that the

epidemiological evidence indicated an

increased risk for cancer by exposure to

chlorinated drinking water, while others

argued that the epidemiological

evidence does not support a health

effects concern. As stated above, EPA

believes that, at this time, a causal link

between exposure to chlorinated

drinking water and development of

cancer cannot be determined. However,

EPA believes that the epidemiological

evidence suggests a potential increased

risk for bladder cancer. It is therefore

prudent public health policy to protect

against this potential public health

concern in light of the uncertainties and

given the large population (over 200

million people) potentially exposed.

2. Reproductive and Developmental

Epidemiology

a. Today’s Rule. EPA has evaluated all

of the reproductive and developmental

epidemiology data and the public

comments received on the 1994

proposal, 1997 NODA, and the 1998

NODA. Based on this evaluation, EPA

believes that the reproductive and

developmental epidemiology data

provides important information that

contributes to the weight-of-evidence

evaluation on the potential risks from

exposure to chlorinated drinking water.

However, the reproductive

epidemiology studies are insufficient to

establish a causal relationship between

exposure to chlorinated drinking water

and reproductive and developmental

effects and are limited for use in the

quantification of risk.

b. Background and Analysis. In the

preamble to the 1994 proposed DBPR,

EPA discussed several reproductive

epidemiology studies (EPA, 1994a). At

the time of the proposal, EPA concluded

that there was no compelling evidence

to indicate a reproductive and

developmental hazard due to exposure

to chlorinated water because the

epidemiologic evidence was inadequate

and the toxicological data were limited.

In 1993, an expert panel of scientists

was convened by the International Life

Sciences Institute to review the

available human studies for

developmental and reproductive

outcomes and to provide research

recommendations (EPA/ILSI, 1993). The

expert panel concluded that the

epidemiologic results should be

considered preliminary given that the

research was at a very early stage (EPA/

ILSI, 1993; Reif et al., 1996). The 1997

NODA and the supporting documents

(EPA, 1997c) presented several new

studies (Savitz et al., 1995; Kanitz et al.

1996; and Bove et al., 1996) that had

been published since the 1994 proposed

rule and the 1993 ILSI panel review.

Based on the new studies presented in

the 1997 NODA, EPA stated that the

results were inconclusive with regard to

the association between exposure to

chlorinated waters and adverse

reproductive and developmental effects

(EPA, 1997b).

In the 1998 DBP NODA (EPA, 1998a),

EPA included the recommendations

from an EPA convened expert panel in

July 1997 to evaluate epidemiologic

studies of adverse reproductive or

developmental outcomes that may be

associated with the consumption of

disinfected drinking water published
69408 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

since the 1993 ILSI panel review. A

report was prepared entitled ‘‘EPA

Panel Report and Recommendations for

Conducting Epidemiological Research

on Possible Reproductive and

Developmental Effects of Exposure to

Disinfected Drinking Water’’ (EPA,

1998f). The 1997 expert panel was also

charged to develop an agenda for further

epidemiological research. The 1997

panel concluded that the results of

several studies suggest that an increased

relative risk of certain adverse outcomes

may be associated with the type of water

source, disinfection practice, or THM

levels. The panel emphasized, however,

that most relative risks are moderate or

small and were found in studies with

limitations in design or conduct. The

small magnitude of the relative risk

found may be due to one or more

sources of bias, as well as to residual

confounding (factors not identified and

controlled). Additional research is

needed to assess whether the observed

associations can be confirmed. In

addition, the 1998 DBP NODA included

a summary of a study by Waller et al.

(1998) conducted in California and

another study by Klotz and Pyrch (1998)

conducted in New Jersey. EPA

concluded that while the Waller et al.

(1998) study does not prove that

exposure to THMs in drinking water

causes early term miscarriages, it does

provide important new information that

needs to be explored and that the study

adds to the weight-of-evidence which

suggests that exposure to DBPs may

have an adverse health effect on

humans. EPA indicated that the review

of the Klotz and Pyrch study (1998) had

not been completed in time for the 1998

NODA.

EPA has completed its review of the

Klotz and Pyrch (1998) study and

concluded that the results in the report

provide limited evidence to substantiate

the hypothesis that DBPs in drinking

water cause adverse reproductive or

developmental effects since the bulk of

the findings are inconclusive. There is,

however, a suggestion in the study that

total THMs or some other component of

surface water is associated with a small

increased risk of neural tube defects; no

significant associations, however, were

observed with individual THMs, HAAs

or other composite measures of

exposure.

c. Summary of Comments. Several

commenters agreed with EPA’s

conclusions on the significance of the

reproductive and developmental effects

from the various studies. Others

believed EPA had not accurately

characterized the potential adverse

reproductive and developmental effects

from exposure to DBPs in drinking

water.

In response, EPA continues to believe

that the available epidemiology data

along with the toxicological findings

suggest that exposure to DBPs may have

adverse effects on humans. However,

EPA believes the epidemiology evidence

is insufficient at this time to conclude

that there is a causal association

between exposure to DBPs and adverse

reproductive and developmental effects.

As noted in the 1998 NODA, EPA has

an epidemiology and toxicology

research program that is examining the

relationship between exposure to DBPs

and adverse reproductive and

developmental effects. In addition, EPA

is pursuing appropriate follow-up

studies to see if the observed association

in the Waller et al. (1998) study can be

replicated elsewhere. EPA will also be

working with the California Department

of Health Services to improve estimates

of exposure to DBPs in the existing

Waller et al. study population. EPA will

collaborate with the Centers for Disease

Control and Prevention (CDC) in a series

of studies to evaluate if there is an

association between exposure to DBPs

in drinking water and birth defects. EPA

is also involved in a collaborative

testing program with the NTP under

which several individual DBPs have

been selected for reproductive and

developmental laboratory animal

studies. This information will be used

in developing the Stage 2 DBPR.

C. MCLs and BAT for TTHM, HAA5,

Chlorite, and Bromate; MRDLs and BAT

for Chlorine, Chloramines, and Chlorine

Dioxide

MCLs are enforceable standards

which are established as close to the

MCLG as feasible. Feasible means with

the use of the best technology, treatment

techniques, and other means which the

Administrator finds available (taking

costs into consideration) after

examining for efficacy under field

conditions and not solely under

laboratory conditions.

EPA is promulgating MCLs for two

groups of DBPs and two inorganic

byproducts. EPA is also promulgating

MRDLs for three disinfectants. EPA is

promulgating these MCLs and MRDLs at

the levels proposed in 1994. Systems

will determine compliance with the

MCLs and MRDLs in the same manner

as was proposed in 1994, except for

chlorite. EPA determined that

additional monitoring requirements for

chlorite were necessary based on the

findings from the CMA two-generation

reproductive and developmental study.

Along with introducing the concept of

the MRDLG in the proposed rule, EPA

also introduced the MRDL for the three

disinfectants (chlorine, chloramines,

and chlorine dioxide). The MRDLs are

enforceable standards, analogous to

MCLs, which recognize the benefits of

adding a disinfectant to water on a

continuous basis and to maintain a

residual to control for pathogens in the

distribution system. As with MCLs, EPA

has set the MRDLs as close to the

MRDLGs as feasible. The Agency has

also identified the BAT which is

feasible for meeting the MRDL for each

disinfectant.

EPA received similar comments on

the use of the term MRDL as with

MRDLG. The majority of commenters

agreed with the use of the term MRDL

for the disinfectants and therefore EPA

is using the term MRDL in the final rule.

1. MCLs for TTHMs and HAA5

a. Today’s Rule. In today’s rule, EPA

is promulgating an MCL for TTHMs of

0.080 mg/L. TTHM is the sum of

measured concentrations of chloroform,

bromodichloromethane,

dibromochloromethane, and

bromoform. EPA is also promulgating an

MCL for HAA5 of 0.060 mg/L. HAA5 is

the sum of measured concentrations of

mono-, di-, and trichloroacetic acids,

and mono- and dibromoacetic acids. A

system is in compliance with these

MCLs when the running annual average

of quarterly averages of all samples

taken in the distribution system,

computed quarterly, is less than or

equal to the MCL. If the running annual

average computed for any quarter

exceeds the MCL, the system is out of

compliance. EPA believes that by

meeting MCLs for TTHMs and HAA5,

water suppliers will also control the

formation of other DBPs not currently

regulated that may also adversely affect

human health.

EPA has identified the best available

(BAT) technology for achieving

compliance with the MCLs for both

TTHMs and HAA5 as enhanced

coagulation or treatment with granular

activated carbon with a ten minute

empty bed contact time and 180 day

reactivation frequency (GAC10), with

chlorine as the primary and residual

disinfectant, as was proposed in 1994.

b. Background and Analysis. The

1994 proposal for the Stage 1 DBPR

included MCLs for TTHM and HAA5 at

0.080 and 0.060 mg/L, respectively

(EPA, 1994a). In addition to the

proposed MCLs, subpart H systems—

utilities treating either surface water or

groundwater under the direct influence

of surface water—that use conventional

treatment (i.e., coagulation,

sedimentation, and filtration) or

precipitative softening would be
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69409

required to remove DBP precursors by

enhanced coagulation or enhanced

softening. The removal of TOC would be

used as a performance indicator for DBP

precursor control.

As part of the proposed rule, EPA

estimated that 17% of PWSs would

need to change their treatment process

to alternative disinfectants (ozone or

chlorine dioxide) or advanced precursor

removal (GAC or membranes) in order

to comply with the Stage 1

requirements. This evaluation was

important to assist in determining

whether the proposed MCLs were

achievable and at what cost. This

evaluation required an understanding of

the baseline occurrence for the DBPs

and TOC being considered in the Stage

1 DBPR, an understanding of the

baseline treatment in-place, and an

estimation of what treatment

technologies systems would use to

comply with the Stage 1 DBPR

requirements.

In 1997, at the direction of the M–DBP

Advisory Committee, the TWG reviewed

MCL compliance predictions developed

for the 1994 proposal because of

concern by several Committee members

that modifications to the rule would

result in more PWSs not being able to

meet the new TTHM and HAA5 MCLs

without installation of higher cost

technologies such as ozone or GAC.

Some members were concerned that

allowing disinfection inactivation credit

prior to precursor removal (by enhanced

coagulation or enhanced softening) in

order to prevent significant reductions

in microbial protection would result in

higher DBP formation and force systems

to install alternative disinfectants or

advanced precursor removal to meet the

1994 proposed TTHM and HAA5 MCLs.

As discussed later in today’s document

in Section III.E (Preoxidation CT Credit),

most PWSs can achieve significant

reduction in DBP formation through the

combination of enhanced coagulation

(or enhanced softening) while

maintaining predisinfection. The TWG’s

analysis indicated that there would be a

decrease in the percentage of PWSs that

would need to install higher cost

technologies. This decrease was

attributed to changes in the proposed

IESWTR which altered the constraints

by which systems could comply with

the MCLs. The requirements of the

IESWTR would also prevent significant

reduction in microbial protection as

described in the 1997 NODA (EPA,

1997a) and elsewhere in today’s Federal

Register. EPA has included a discussion

of the prediction of technology choices

in Section IV (Economic Analysis) of

today’s rule and a more detailed

discussion in the RIA for this rule (EPA,

1998g). EPA continues to believe the

proposed MCLs are achievable without

large-scale technology shifts.

c. Summary of Comments. Several

commenters questioned whether the

TTHM MCL of 0.080 mg/L and the

HAA5 MCL of 0.060 mg/L were set at a

level that would preclude the use of

chlorine as an effective disinfectant.

EPA does not believe the MCLs will

preclude the use of chlorine. While

there are currently systems that are

exceeding these MCLs, the Agency has

concluded that most systems will be

able to achieve compliance by relatively

low cost alternatives such as: improved

DBP precursor removal through

enhanced coagulation or enhanced

softening; moving the point of

disinfection to reduce the reaction

between chlorine and DBP precursors;

the use of chloramines for residual

disinfection instead of chlorine; or a

combination of these alternatives.

Many commenters also questioned the

need for a modified TTHM MCL and a

new MCL for HAA5. As discussed in

section I.B.2. of today’s rule, EPA

believes the potential public health risks

do justify a reduction in exposure to

DBPs and hence a modification in the

MCL for TTHMs and a new MCL for

HAA5. Also as discussed in section IV

of this rule, EPA continues to believe

that the potential risks associated with

both TTHM and HAA5 and unregulated

DBPs will be reduced by the

combination of these MCLs and DBP

precursor removal through enhanced

coagulation and enhanced softening.

While most commenters agreed with

EPA’s definition of GAC10 and GAC20

(GAC with a 10 and a 20 minute empty

bed contact time, respectively), several

commenters thought that designating

GAC as BAT meant that they would

have to install GAC at their treatment

plant. EPA is required to designate a

BAT for any MCL that the Agency

promulgates; however, a system may

use any technology it wants to comply

with the MCL. However, a system must

install BAT prior to the State issuing a

variance to one of these MCLs.

Commenters also questioned the use

of group MCLs for TTHM and HAA5,

instead of MCLs for the individual

DBPs, since a group MCL does not take

into account differing health effects and

potencies of individual DBPs. EPA

continues to believe that regulating

TTHMs and HAAs as group MCLs is

appropriate at this time for several

reasons. First, EPA does not have

adequate occurrence data for individual

trihalomethanes and haloacetic acids to

develop national occurrence estimates

which are needed for estimating the

potential costs and benefits of the rule

(although the Agency has an adequate

database of group occurrence). Second,

there is not an adequate understanding

of how water quality parameters (such

as pH, temperature, bromide, and

alkalinity) affect individual THM and

HAA formation. Third, EPA does not

have an adequate understanding of how

treatment technologies control the

formation of individual THMs and

HAAs to enable specifying appropriate

MCLs for individual TTHMs or HAAs at

this time. Finally, there are inadequate

health data to characterize the potential

health risks for several of the HAAs and

to then determine the potential benefits

from reduction in exposures. In

conclusion, EPA continues to believe

the most appropriate approach for

reducing the health risk from all DBPs

is by the combination of TTHM and

HAA5 MCLs and DBP precursor

removal.

Some commenters stated that EPA

may have underestimated HAA

formation, especially in certain areas of

the country. The Agency was aware that

waters in particular regions of the

country would be more difficult to treat

in order to control for HAA5 than for

TTHM. Based on additional data

received since the proposal, EPA

continues to believe that the HAA5 MCL

can be met by most systems through the

same general low-cost strategies as used

for TTHM (e.g., improved DBP

precursor removal, moving the point of

disinfection, use of chloramines for

residual disinfection) rather than higher

cost alternatives (see section IV.C for

cost estimates of technology treatment

choices).

Many commenters also requested that

States be granted sufficient flexibility in

implementing this rule. While the State

must adopt rules that are at least as

stringent as those published in today’s

rule, EPA has given the States and

systems much latitude in monitoring

plans (frequency and location),

allowable disinfectants, and other rule

elements. Much of this flexibility carries

over from the 1979 TTHM Rule (EPA,

1979).

Finally, some commenters stated that

requirements in this rule are

complicated. EPA acknowledges that

this rule is complicated, but that this

complexity is necessary in order to

adequately and economically address

the potential DBP risks. EPA was

required to consider a host of

complicating factors in developing

regulatory requirements: different

disinfectants, different health effects

(acute and chronic), different DBP

formation kinetics, different source

water types and qualities, different

treatment processes, and the need for
69410 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

simultaneous compliance with other

rules such as the Total Coliform Rule,

Lead and Copper Rule, and Interim

Enhanced Surface Water Treatment

Rule. The Agency chose to evaluate all

these factors by developing

requirements that minimized impacts

on various classes of systems while

enabling States to implement the rule.

In addition to the further description of

the requirements in today’s rule, EPA

will publish a State implementation

manual, a small system compliance

manual, and a series of guidance

manuals that will provide additional

information to systems and States in

implementing this rule.

EPA has reviewed all comments and

determined that the requirements

promulgated today are necessary to

control the occurrence of TTHM and

HAA5 and are feasible to achieve. These

requirements take into account the

difficulties in simultaneously

controlling risks from DBPs and

pathogens, while appropriately

addressing implementation and

compliance issues.

2. MCL for Bromate

a. Today’s Rule. In today’s rule, EPA

is promulgating an MCL for bromate of

0.010 mg/L. Bromate is one of the

principal byproducts of ozonation in

bromide-containing source waters. The

proposed MCL for bromate was 0.010

mg/l. A system is in compliance with

the MCL when the running annual

average of monthly samples, computed

quarterly, is less than or equal to the

MCL. If the running annual average

computed for any quarter exceeds the

MCL, the system is out of compliance.

EPA has identified the BAT for

achieving compliance with the MCL for

bromate as control of ozone treatment

process to reduce formation of bromate,

as was proposed in 1994 (EPA, 1994a).

b. Background and Analysis. For

systems using ozone, a separate MCL

was proposed for the primary inorganic

DBP associated with ozone usage:

bromate. Although the theoretical 10¥4

risk level for bromate is 0.005 mg/l, an

MCL of 0.010 mg/L was proposed

because available analytical detection

methods for bromate were reliable only

to the projected practical quantification

limit (PQL) of 0.01 mg/L (EPA, 1994a).

In the preamble to the proposed rule,

EPA requested comment on whether

there were ways to set (or achieve) a

lower MCL (i.e., 0.005 mg/L [5 μg/L])

and whether the PQL for bromate could

be lowered to 5 μg/L in order to allow

compliance determinations for a lower

MCL in Stage 1 of the proposed rule.

The proposed MCL of 0.010 mg/L for

bromate was based on a projected PQL

that would be achieved by improved

methods. The PQL of the revised

method is approximately 0.010 mg/L for

bromate, as discussed in Section III.G

(Analytical Methods). At the time of the

November 1997 NODA, EPA was not

aware of any new information that

would lower the PQL for bromate and

thus allow lowering the MCL. As a

result, EPA concluded that the proposed

bromate MCL was appropriate.

c. Summary of Comments. Several

commenters were concerned that the

bromate MCL may have been set at a

level that would preclude the use of

ozone. During the M–DBP Advisory

Committee discussions, the TWG

evaluated the feasibility of ozone for

certain systems that were predicted to

have problems in complying with the

TTHM and HAA5 MCLs. While ozone

was not feasible for all systems, it was

feasible for many that did not have

elevated source water bromide levels to

react with ozone to form bromate. The

TWG predicted that most of the systems

not able to use ozone would be able to

switch to chlorine dioxide for primary

disinfection.

EPA has reviewed all comments and

determined that the requirements

promulgated today are necessary to

control the occurrence of bromate and

are feasible to achieve. For additional

discussion on the treatment

technologies for controlling bromate

formation and their costs see the Cost

and Technology Document for

Controlling Disinfectants and

Disinfection Byproducts (EPA, 1998k).

These requirements take into account

the difficulties in simultaneously

controlling risks from DBPs and

pathogens, while appropriately

addressing compliance and

implementation issues. In addition, the

Reg. Neg. Committee and the M–DBP

Advisory Committee supported these

conclusions.

3. MCL for Chlorite

a. Today’s Rule. In today’s rule, EPA

is promulgating an MCL for chlorite of

1.0 mg/L. EPA has modified the

monitoring requirements from the

proposed rule for the reasons discussed

in section III.A.7. The issue of

monitoring and MCL compliance

determinations as they relate to the

health effect of concern for chlorite were

discussed in the proposed rule (EPA,

1994a). CWSs and NTNCWSs using

chlorine dioxide for disinfection or

oxidation are required to conduct

sampling for chlorite both daily at the

entrance to the distribution system and

monthly (3 samples on the same day)

within the distribution system.

Additional distribution system

monitoring is required when the

chlorite concentration measured at the

entrance to the distribution system

exceeds a chlorite concentration of 1.0

mg/L. Distribution system monitoring

may be reduced if certain conditions are

met (described in section III.H of this

rule).

b. Background and Analysis. For

systems using chlorine dioxide, EPA

proposed a separate MCL for chlorite

associated with its usage in 1994. The

proposed chlorite MCL of 1.0 mg/L was

supported by the Reg. Neg. Committee

because 1.0 mg/L was the lowest level

considered practicably achievable by

typical systems using chlorine dioxide,

from both treatment and monitoring

perspectives. The MCLG was 0.08 mg/

L, due (in part) to data gaps that

required higher uncertainty factors in

the MCLG determination. The CMA

agreed to fund new health effects

research on chlorine dioxide and

chlorite—with EPA approval of the

experimental design—to resolve these

data gaps. EPA completed its review of

the study and published its findings in

a NODA in March 1998. Those findings

led to a chlorite MCLG of 0.8 mg/L and

support for an MCL of 1.0 mg/L.

c. Summary of Comments. Many

commenters requested that EPA not

modify the MCL for chlorite prior to

receipt and evaluation of the CMA

study, since lowering the MCL could

preclude the use of chlorine dioxide for

drinking water disinfection. EPA has

evaluated the CMA study and

concluded that the MCLG for chlorite

should be 0.8 mg/L. EPA believes the

proposed MCL of 1.0 mg/L, based on a

three sample average to determine

compliance, is appropriate because this

is the lowest level achievable by typical

systems using chlorine dioxide. In

addition, considering the margin of

safety that is factored into the estimate

of the MCLG, EPA believes the MCL

will be protective of public health. Once

the final MCLG was established, EPA

decided that the chlorite MCL should be

finalized at the level proposed which

was as close as economically and

technically feasible to the MCLG, and

modified the proposed requirements for

monitoirng and compliance in response

to the health concerns associated with

chlorite.

EPA has reviewed all comments and

determined that the requirements

promulgated today are necessary to

control the occurrence of chlorite and

are feasible to achieve. These

requirements take into account the

difficulties in simultaneously

controlling risks from DBPs and

pathogens, while appropriately

addressing compliance and
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69411

implementation issues. In addition, the

Reg. Neg. Committee and the M–DBP

Advisory Committee supported these

conclusions.

4. MRDL for Chlorine

a. Today’s Rule. Chlorine is a widely

used and highly effective water

disinfectant. In today’s rule, EPA is

promulgating an MRDL for chlorine of

4.0 mg/L. As a minimum, CWSs and

NTNCWSs must measure the residual

disinfectant level at the same points in

the distribution system and at the same

time as total coliforms, as specified in

§ 141.21. Subpart H systems may use the

results of residual disinfectant

concentration sampling done under the

SWTR (§ 141.74(b)(6) for unfiltered

systems, § 141.74(c)(3) for systems that

filter) in lieu of taking separate samples.

Monitoring for chlorine may not be

reduced.

A system is in compliance with the

MRDL when the running annual average

of monthly averages of all samples,

computed quarterly, is less than or

equal to the MRDL. Notwithstanding the

MRDL, operators may increase residual

chlorine levels in the distribution

system to a level and for a time

necessary to protect public health to

address specific microbiological

contamination problems (e.g., including

distribution line breaks, storm runoff

events, source water contamination, or

cross-connections).

EPA has identified the best means

available for achieving compliance with

the MRDL for chlorine as control of

treatment processes to reduce

disinfectant demand, and control of

disinfection treatment processes to

reduce disinfectant levels.

b. Background and Analysis. The

1994 proposed Stage I DBPR included

an MRDL for chlorine at 4.0 mg/L (EPA,

1994a). The MRDL for chlorine is equal

to the MRDLG for chlorine. EPA

requested comment on a number of

issues relating to the calculation of the

MRDLG for chlorine. New information

on chlorine has become available since

the 1994 proposal and was discussed in

the 1997 NODA (EPA, 1997b). EPA

believes that no new information has

become available to warrant changing

the proposed MRDL. EPA has therefore

decided to promulgate the MRDL of 4.0

mg/L for chlorine.

c. Summary of Comments. Some

commenters expressed concern that the

MRDL for chlorine is too high. These

commenters were concerned that 4 mg/

L levels of chlorine would have a

detrimental effect on piping materials

and would cause taste and odor

problems. One commenter supported

the chlorine MRDL and the methods of

calculating compliance with the MRDL.

This commenter felt that 4.0 mg/L

appropriately allows for disinfection

under varying circumstances. One

commenter requested that EPA increase

the flexibility of utilities to meet the

MRDL for chlorine during periods when

chlorine levels in the distribution

systems may need to be raised to protect

public health.

EPA believes that the MRDL of 4.0

mg/L for chlorine is appropriate to

control for potential health effects

(MRDLG is 4.0 mg/L) from chlorine

while high enough to allow for control

of pathogens under a variety of

conditions. EPA also believes that

compliance based on a running annual

average of monthly averages of all

samples, computed quarterly is

sufficient to allow systems to increase

residual chlorine levels in the

distribution system to a level and for a

time necessary to protect public health

to address specific microbiological

contamination problems and still

maintain compliance. If a system has

taste and odor problems associated with

excess chlorine levels it can lower its

level of chlorine. Since there may not be

any health effects associated with taste

and odor problems, EPA does not have

a statutory requirement to address this

concern.

5. MRDL for Chloramines

a. Today’s Rule. Chloramines are

formed when ammonia is added during

chlorination. In today’s rule, EPA is

promulgating an MRDL for chloramines

of 4.0 mg/L (measured as combined total

chlorine). As a minimum, CWSs and

NTNCWSs must measure the residual

disinfectant level at the same points in

the distribution system and at the same

time as total coliforms, as specified in

§ 141.21. Subpart H systems may use the

results of residual disinfectant

concentration sampling done under the

SWTR (§ 141.74(b)(6) for unfiltered

systems, § 141.74(c)(3) for systems that

filter) in lieu of taking separate samples.

Monitoring for chloramines may not be

reduced.

A PWS is in compliance with the

MRDL when the running annual average

of monthly averages of all samples,

computed quarterly, is less than or

equal to the MRDL. Notwithstanding the

MRDL, operators may increase residual

chloramine levels in the distribution

system to a level and for a time

necessary to protect public health to

address specific microbiological

contamination problems (e.g., including

distribution line breaks, storm runoff

events, source water contamination, or

cross-connections).

EPA has identified the best means

available for achieving compliance with

the MRDL for chloramines as control of

treatment processes to reduce

disinfectant demand, and control of

disinfection treatment processes to

reduce disinfectant levels.

b. Background and Analysis. The

1994 proposed Stage 1 DBPR included

an MRDL for chloramines at 4.0 mg/L

(EPA, 1994a). The MRDL for

chloramines is equal to the MRDLG for

chloramines. EPA requested comment

on a number of issues relating to the

calculation of the MRDLG for

chloramines. New information on

chloramines has become available since

the 1994 proposal and was cited in the

1997 NODA and is included in the

public docket for this rule (EPA, 1997b).

This new information did not contain

data that would warrant changing the

MRDL. EPA has therefore decided to

promulgate the proposed MRDL of 4.0

mg/L for chloramines.

c. Summary of Comments. Some

commenters remarked that systems with

high concentrations of ammonia would

have difficulty meeting the MRDL for

chloramine of 4.0 mg/L and still

maintain adequate microbial protection.

One commenter felt that there should

not be a limit for chloramine residual

due to variations in parameters such as

distribution system configurations and

temperature. One commenter felt that

the MRDL for chloramines was too low

and should not be set at the same level

as the chlorine MRDL since chlorine is

a stronger disinfectant than

chloramines. This commenter felt that

limiting the chloramine residual would

reduce the capability to sustain high

water quality in the distribution system.

One commenter supported the

chloramine MRDL and the methods of

calculating compliance with the MRDL.

This commenter felt that 4.0 mg/L

adequately allows for disinfection under

varying circumstances.

EPA believes that compliance based

on a running annual average of monthly

averages of all samples, computed

quarterly, is sufficient to allow systems

to increase residual chloramine levels in

the distribution system to a level and for

a time necessary to protect public health

to address specific microbiological

contamination problems and still

maintain compliance. The MRDL for

chloramine does not limit disinfectant

dosage but rather disinfectant residual

in the distribution system. EPA

therefore, believes that systems with

high levels of ammonia should be able

to comply with the MRDL. Systems that

have difficulty sustaining high water

quality in the distribution system

should consider modifying their
69412 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

treatment or maintenance procedures to

reduce demand. Although chlorine is a

stronger disinfectant than chloramine,

EPA believes that an MRDL of 4.0 mg/

L is sufficient to provide adequate

microbial protection.

6. MRDL for Chlorine Dioxide

a. Today’s Rule. Chlorine dioxide is

used primarily for the oxidation of taste

and odor-causing organic compounds in

water. It can also be used for the

oxidation of reduced iron and

manganese and color, and as a

disinfectant and algicide. Chlorine

dioxide reacts with impurities in water

very rapidly, and is dissipated quickly.

In today’s rule, EPA is promulgating an

MRDL of 0.8 mg/L for chlorine dioxide.

Unlike chlorine and chloramines, the

MRDL for chlorine dioxide may not be

exceeded for short periods of time to

address specific microbiological

contamination problems because of

potential health concerns with shortterm exposure to chlorine dioxide above

the MCL.

CWSs and noncommunity systems

must monitor for chlorine dioxide only

if chlorine dioxide is used by the system

for disinfection or oxidation. Monitoring

for chlorine dioxide may not be

reduced. If monitoring is required,

systems must take daily samples at the

entrance to the distribution system. If

any daily sample taken at the entrance

to the distribution system exceeds the

MRDL, the system is required to take

three additional samples in the

distribution system on the next day.

Systems using chlorine as a residual

disinfectant and operating booster

chlorination stations after the first

customer must take three samples in the

distribution system: one as close as

possible to the first customer, one in a

location representative of average

residence time, and one as close as

possible to the end of the distribution

system (reflecting maximum residence

time in the distribution system).

Systems using chlorine dioxide or

chloramines as a residual disinfectant or

chlorine as a residual disinfectant and

not operating booster chlorination

stations after the first customer must

take three samples in the distribution

system as close as possible to the first

customer at intervals of not less than six

hours.

If any daily sample taken at the

entrance to the distribution system

exceeds the MRDL and if, on the

following day, any sample taken in the

distribution system also exceeds the

MRDL, the system will be in acute

violation of the MRDL and must take

immediate corrective action to lower the

occurrence of chlorine dioxide below

the MRDL and issue the required acute

public notification. Failure to monitor

in the distribution system on the day

following an exceedance of the chlorine

dioxide MRDL shall also be considered

an acute MRDL violation.

If any two consecutive daily samples

taken at the entrance to the distribution

system exceed the MRDL, but none of

the samples taken in the distribution

system exceed the MRDL, the system

will be in nonacute violation of the

MRDL and must take immediate

corrective action to lower the

occurrence of chlorine dioxide below

the MRDL. Failure to monitor at the

entrance to the distribution system on

the day following an exceedance of the

chlorine dioxide MRDL shall also be

considered a nonacute MRDL violation.

EPA has identified the best means

available for achieving compliance with

the MRDL for chlorine dioxide as

control of treatment processes to reduce

disinfectant demand, and control of

disinfection treatment processes to

reduce disinfectant levels.

b. Background and Analysis. EPA

proposed an MRDL for chlorine dioxide

of 0.8 mg/L in 1994. The MRDL was

determined considering the tradeoffs

between chemical toxicity and the

beneficial use of chlorine dioxide as a

disinfectant. The Reg. Neg. Committee

agreed to this MRDL with the

reservation that it would be revisited, if

necessary, after completion of a twogeneration reproductive study by CMA.

As discussed above for chlorite, a

two-generation reproductive study on

chlorite, which is relevant to health

effects of chlorine dioxide, was

completed by the CMA. EPA completed

its review of this study and published

its findings in a NODA in March 1998

(EPA, 1998a). Based on its assessment of

the CMA study and a reassessment of

the noncancer health risk for chlorite

and chlorine dioxide, EPA concluded

that the MRDLG for chlorine dioxide be

changed from 0.3 mg/L to 0.8 mg/L.

Since this new MRDLG was equal to the

proposed MRDL for chlorine dioxide,

the MRDL will remain 0.8 mg/L.

c. Summary of Comments. A number

of commenters were concerned that the

MRDL for chlorine dioxide not be

lowered below the proposed level of 0.8

mg/L because this would preclude the

use of chlorine dioxide as a water

disinfectant. One commenter supported

the MRDL for chlorine dioxide based on

public health protection, adequate

microbial protection, and technical

feasibility. One commenter agreed that a

running annual average of samples for

compliance determination should not be

allowed for chlorine dioxide. One

commenter was concerned that the

chlorine dioxide MRDL was too high

and that EPA should consider children

and vulnerable populations in

establishing drinking water standards.

EPA has reassessed the health effects

data on chlorine dioxide, including the

new CMA two-generation study and

determined that the MRDL should

remain at 0.8 mg/L as proposed. EPA

believes that this MRDL is set at a

technically feasible level for the

majority of chlorine dioxide plants. This

is the case because EPA considered

children and susceptible populations in

its MRDLG determination (EPA, 1998h).

The MRDL is set as close to this MRDLG

as is technically and economically

feasible.

D. Treatment Technique Requirement

1. Today’s Rule

Today’s rule establishes treatment

technique requirements for removal of

TOC to reduce the formation of DBPs by

means of enhanced coagulation or

enhanced softening. The treatment

technique applies to Subpart H systems

using conventional filtration treatment

regardless of size. Subpart H systems are

systems with conventional treatment

trains that use surface water or ground

water under the influence of surface

water as their source. The treatment

technique requirement has two steps of

application. Step 1 specifies the

percentage of influent TOC a plant must

remove based on the raw water TOC and

alkalinity levels. The matrix in Table

III–1 specifies the removal percentages.

TABLE III–1.—REQUIRED REMOVAL OF TOTAL ORGANIC CARBON BY ENHANCED COAGULATION AND ENHANCED

SOFTENING FOR SUBPART H SYSTEMS USING CONVENTIONAL TREATMENT a,b

Source water TOC (mg/L)

Source water alkalinity (mg/L as CaCO3)

0–60 (percent) >60–120 (percent)

>120c (percent)

>2.0–4.0 ....................................................................................................................................... 35.0 25.0 15.0
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69413

TABLE III–1.—REQUIRED REMOVAL OF TOTAL ORGANIC CARBON BY ENHANCED COAGULATION AND ENHANCED

SOFTENING FOR SUBPART H SYSTEMS USING CONVENTIONAL TREATMENT a,b—Continued

Source water TOC (mg/L)

Source water alkalinity (mg/L as CaCO3)

0–60 (percent) >60–120 (percent)

>120c (percent)

>4.0–8.0 ....................................................................................................................................... 45.0 35.0 25.0

>8.0 .............................................................................................................................................. 50.0 40.0 30.0

aSystems meeting at least one of the conditions in Section 141.135(a)(2) (i)–(vi) of the rule are not required to meet the removals in this table.

bSoftening systems meeting one of the two alternative compliance criteria in Section 141.135(a)(3) of the rule are not required to meet the removals in this table. cSystems practicing softening must meet the TOC removal requirements in the last column to the right.

Step 2 provides alternate performance

criteria when it is technically infeasible

for systems to meet the Step 1 TOC

removal requirements. For systems

practicing enhanced coagulation, Step 2

of the treatment technique requirement

is used to set an alternative TOC

removal requirement (i.e. alternative

percent removal of raw water TOC) for

those systems unable to meet the TOC

removal percentages specified in the

matrix. The alternative TOC removal

percentage is determined by performing

jar tests on at least a quarterly basis for

one year. During the jar tests, alum or

an equivalent dose of ferric coagulant is

added in 10 mg/L increments until the

pH is lowered to the target pH value.

The target pH is the value the sample

must be at or below before the

incremental addition of coagulant can

be discontinued. For the alkalinity

ranges 0–60, >60–120, >120–240, and

>240 mg/L (as CaCO3), the target pH

values are 5.5, 6.3, 7.0, and 7.5,

respectively. Once the Step 2 jar test is

complete, the TOC removal (mg/L) is

then plotted versus coagulant dose (mg/

L). The alternative TOC removal

percentage is set at the point of

diminishing returns (PODR) identified

on the plot.

Today’s rule defines the PODR as the

point on the TOC versus coagulant dose

plot where the slope changes from

greater than 0.3/10 to less than 0.3/10

and remains less than 0.3/10. After

identifying the PODR, the alternative

TOC removal percentage can be set. If

the TOC removal versus coagulant dose

plot does not meet the PODR definition,

the water is considered not amenable to

enhanced coagulation and TOC removal

is not required if the PWS requests, and

is granted, a waiver from the enhanced

coagulation requirements by the State.

Systems are required to meet the

alternative TOC removal requirements

during full-scale operation to maintain

compliance with the treatment

technique. For the technical reasons

outlined in the 1997 DBP NODA (EPA

1997b), EPA has concluded that this

definition of the PODR is a reliable

indicator of the amount of TOC that is

feasible to remove.

Systems practicing enhanced

softening are not required to perform jar

testing under today’s treatment

technique as part of a Step 2 procedure.

Rather, they are required to meet one of

three alternative performance criteria if

they cannot meet the Step 1 TOC

removal requirements. These criteria

are: (1) Produce a finished water with a

SUVA of less than or equal to 2.0 L/mgm; (2) remove a minimum of 10 mg/L

magnesium hardness (as CaCO3); or (3)

lower alkalinity to less then 60 mg/L (as

CaCO3). All three of these alternative

performance criteria are measured

monthly and can be calculated quarterly

as a running annual average to

demonstrate compliance. As discussed

in the 1997 DBP NODA (EPA 1997b)

EPA has not been able, from a technical

and engineering standpoint, to identify

a Step 2 testing procedure at this time

that allows softening systems to set an

alternative TOC removal amount.

Enhanced softening systems unable to

meet the Step 1 TOC removal

requirements or any of the three

alternative performance criteria may

apply to the State for a waiver from the

treatment technique requirements. EPA

believes the three alternative

performance criteria listed above

provide assurance that softening

systems have maximized TOC removal

to the extent feasible.

Today’s rule also provides alternative

compliance criteria—which are separate

and independent of the Step 2 enhanced

coagulation procedure and the

enhanced softening alternative

performance criteria—from the

treatment technique requirements

provided certain conditions are met.

These criteria are:

(1) the system’s source water TOC is

<2.0 mg/L;

(2) the system’s treated water TOC is

<2.0 mg/L;

(3) the system’s source water TOC

<4.0 mg/L, its source water alkalinity is

>60 mg/L (as CaCO3), and the system is

achieving TTHM <40μg/L and HAA5

<30μg/L (or the system has made a clear

and irrevocable financial commitment

to technologies that will meet the TTHM

and HAA level);

(4) the system’s TTHM is <40μg/L,

HAA5 is <30μg/L, and only chlorine is

used for primary disinfection and

maintenance of a distribution system

residual;

(5) the system’s source water SUVA

prior to any treatment is ≤ 2.0 L/mg–m;

and

(6) the system’s treated water SUVA is

≤ 2.0 L/mg–m.

Alternative compliance criteria 1, 2, 5,

and 6 are determined based on monthly

monitoring calculated quarterly as a

running annual average of all

measurements. Alternative compliance

criteria 3 is based on monthly

monitoring for TOC and alkalinity or

quarterly monitoring for TTHMs and

HAA5, calculated quarterly as a running

annual average of all measurements.

Alternative criteria 4 is determined

based on monitoring for TTHMs and

HAA5, calculated quarterly as a running

annual average of all measurements.

SUVA, an indicator of DBP precursor

removal treatability, is defined as the

UV–254 (measured in m¥1) divided by

the DOC concentration (measured as

mg/L).

2. Background and Analysis

The general structure of the 1994

proposed rule and today’s final rule are

similar. The 1994 proposal included an

enhanced coagulation and enhanced

softening treatment technique

requirement for Subpart H systems. The

1994 proposed rule included a TOC

removal matrix for Step 1 TOC removal

requirements and it also provided for a

Step 2 jar test procedure for systems

practicing enhanced coagulation. The

PODR for the Step 2 procedure was

defined as a slope of .3/10 on the TOC

removal versus coagulant dose plot. The

Step 2 procedure included a maximum

pH value, now referred to as the ‘‘target

pH’’ for conducting the jar tests and it

also allowed systems to request a waiver

from the State if the PODR was never
69414 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

attained. The target pH values in the

1994 proposal were the same as those in

today’s final rule. A Step 2 procedure

for enhanced softening systems was not

specified in the proposal.

The proposed rule also provided for a

number of exceptions to the enhanced

coagulation and enhanced softening

requirements, but it did not include use

of SUVA as an alternative compliance

criteria.

A major goal of the TOC removal

treatment technique requirements was

to minimize transactional costs to the

States both in terms of limiting the

number of systems seeking alternative

performance criteria and in providing

relatively simple methodologies for

determining alternative performance

criteria. In the 1997 DBP NODA (EPA

1997b), EPA presented new data and

analysis and the basis for modifying the

proposed criteria to those described in

today’s final rule. The 1997 NODA also

solicited public comment on EPA’s

intended changes to the proposal and

the recommendations of the M–DBP

Advisory Committee to EPA. An

overview of the key points in the 1997

NODA most pertinent to modifying the

treatment technique requirements are

presented below.

Data Supporting Changes in the TOC

Removal Requirements. The proposed

TOC removal percentages, which were

set with the intent that 90% of affected

systems would be able to achieve them,

were developed with limited data. Since

the proposal, several jar studies and

analyses of full-scale plant TOC removal

performance have been performed. They

were analyzed by EPA as part of the M–

DBP Advisory Committee process. This

data will not be thoroughly reviewed

here; instead, the major points salient to

development of the final regulation will

be summarized. See the 1997 DBP

NODA (EPA 1997b) to review EPA’s

detailed analysis of the new data.

As discussed in greater detail in the

1997 DBP NODA, research by Singer et

al. (1995) indicated that a significant

number of waters, especially low-TOC,

high-alkalinity waters in the first row of

the proposed TOC removal matrix,

would probably not be able to meet the

TOC removal percentages and would

therefore need to use the Step 2 protocol

to establish alternative performance

criteria. The Singer et al. (1995) study

raised concern regarding the number of

systems that might need to use the Step

2 procedure to set alternative

performance criteria. A study by

Malcolm Pirnie, Inc. and Colorado

University addressed this issue by

developing a nationally representative

database of 127 source waters and used

this data to develop a model to predict

enhanced coagulation’s ability to

remove TOC from different source

waters (Edwards, 1997; Tseng &

Edwards, 1997; Chowdhury, 1997). The

model was subsequently used to analyze

the level or percentage of TOC removal

that is operationally feasible to achieve

for the boxes in the proposed TOC

removal matrix. Nine predictive

equations for TOC removal were

developed, one for each box of the TOC

removal matrix, to select TOC removal

percentages that could be ‘‘reasonably’’

met by 90 percent of the systems

implementing enhanced coagulation.

The equations indicated that many

systems having source waters within the

low TOC boxes of the matrix (i.e. 2.0–

4.0 mg/L, the first row of the matrix)

would meet the Step 2 slope criterion

before meeting the required TOC

removal percentages. In other words,

less than 90 percent of the systems in

this row could achieve the proposed

TOC removal with reasonable coagulant

doses. The equations indicated that the

TOC removal percentages in the

medium and high TOC boxes (the

bottom two rows of the matrix) could be

met by approximately 90 percent of the

systems in these boxes. The research

team also examined 90th-percentile

SUVA curves, in conjunction with the

nine TOC removal curves, to predict

what TOC removal percentage is

appropriate for each of the nine boxes

of the matrix.

An analysis of full-scale TOC removal

has also been performed since 1994.

Data was obtained from 76 treatment

plants of the American Water Works

Service Company (AWWSCo) system,

plants studied by Randtke et al. (1994),

and plants studied by Singer et al.

(1995). These data represent a one-time

sampling at each plant under current

operating conditions when enhanced

coagulation was not being practiced.

This sampling is different from the

proposed compliance requirements

which would be based on an annual

average of monthly samples. Based on

current treatment at the plants in the

study, 83 percent of the systems treating

moderate-TOC, low-alkalinity water

removed an amount of TOC greater than

that required by the TOC removal

matrix, whereas only 14 percent of the

systems treating water with low TOC

and high alkalinity met the proposed

TOC removal requirements. The results

of the survey, coupled with the

information discussed in the preceding

paragraph, indicate that the proposed

TOC removal percentages in the top row

of the matrix might be too high for 90

percent of plants to avoid the Step 2

procedure, while the removal

percentages in the bottom two rows may

be reasonable and allow 90 percent of

plants to avoid the Step 2 procedure.

Therefore, the TOC removal percentages

in the first row have been lowered 5.0

percentage points to enable 90 percent

of plants to comply without

unreasonable coagulant dosage or

resorting to the Step 2 procedure.

Data Supporting the Use of SUVA as

an Exemption from Treatment

Technique Requirements. At the time of

the proposal, insufficient data on SUVA

was available to define precise criteria

for when enhanced coagulation would

not be effective for removing DBP

precursors. The M–DBP Advisory

Committee examined the role of SUVA

as an indicator of the amount of DBP

precursor material enhanced

coagulation is capable of removing. It

has been well established that

coagulation primarily removes the

humic fraction of the natural organic

matter (NOM) in water (Owen et al.,

1993). Furthermore, Edzwald and Van

Benschoten (1990) have found SUVA to

be a good indicator of a water’s humic

content. The humic fraction of a water’s

organic content significantly affects DBP

formation upon chlorination.

A study by White et al. (1997) showed

that waters with high initial SUVA

values exhibited significant reductions

in SUVA as a result of coagulation,

demonstrating a substantial removal of

the humic (and other UV-absorbing)

components of the organic matter,

whereas waters with low initial SUVA

values exhibited relatively low

reductions in SUVA. For all of the

waters examined, the SUVA tended to

plateau at high alum doses, reflecting

that the residual organic matter was

primarily non-humic and therefore

unamenable to removal by enhanced

coagulation. SUVA’s ability to indicate

the amount of humic matter present,

and enhanced coagulation’s ability to

preferentially remove humic matter,

logically establishes SUVA as an

indicator of enhanced coagulation’s

ability to remove humic substances from

a given water. The M–DBP Advisory

Committee therefore recommended that

a SUVA value ≤ 2.0 L/mg–m be an

exemption from the treatment technique

requirement and that this SUVA value

also be added as a Step 2 procedure.

Effect of Coagulant Dose on TOC

Removal for Enhanced Softening. At the

time of proposal, limited data was

available on the effectiveness of TOC

removal by enhanced coagulation and

enhanced softening and on conditions

that define feasibility. Several studies

examined the relationship between

increased coagulant dose and TOC

removal (Shorney et al., 1996; Clark et
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69415

al. 1994). These studies indicate some

improvement in TOC removal with

small doses of iron salts (5 mg/L ferric

sulfate), but no additional TOC removal

during softening occurred with

increased coagulant addition (up to 25

mg/L dose). Pilot testing by the City of

Austin’s softening plant confirmed the

study’s jar test results by showing that

increasing ferric sulfate doses beyond

the level required for turbidity removal

provided no additional TOC removal.

Multiple jar tests on various waters

performed by Singer et al. (1996)

examined the relationship between use

of lime and soda ash and TOC removal.

Only lime and soda ash (no coagulants)

were used in the tests. The study

showed the removal of 10 mg/L of

magnesium hardness would probably

have less of an impact on plant residual

generation than using a lime soda-ash

process. However, the amount of

residual material generated under both

scenarios could be substantial.

Step 2 Requirements for Softening

Systems. As stated above, the proposed

rule did not include a Step 2 procedure

for softening plants because of a lack of

data. The M-DBP Advisory Committee

examined new data that had been

collected since the proposal to

determine if a Step 2 procedure for

softening plants could be identified.

Data included the current TOC removals

being achieved by softening plants

covered by the ICR (49 plants). The data

were analyzed to find the appropriate

TOC removal levels for softening plants.

The results of plotting the average TOC

percent removals on a percentile basis

indicated that the relative impact of

meeting the TOC removal requirement

in the proposed rule would be greatest

in the low TOC group (>2–4 mg/L).

However, forcing a plant to increase pH

may require it to add soda ash (due to

the decrease in alkalinity caused by

high lime dose necessary to raise the

pH). This would be a significant

treatment change due to the additional

solids generation and because

significant amounts of magnesium

hydroxide may precipitate at the higher

pH. Most softening plants are normally

operated without soda ash addition

because of the high cost of soda ash, the

additional sludge production, the

increased chemical addition to stabilize

the water, and the increased sodium

levels in the finished water (Randtke et

al., 1994 and Shorney et al., 1996). Due

to these difficulties, EPA does not

currently believe that a lime and sodaash softening process would be a viable

Step 2 procedure for softening systems.

The final rule instead specifies two

alternative compliance criteria,

mentioned earlier in this section, as a

Step 2 procedure for softening systems.

3. Summary of Comments

A large number of comments on the

1994 proposal questioned whether the

required TOC removal percentages

could be obtained by 90 percent of

affected systems. In response, since the

time of proposal, a large body of

additional data and analysis has been

developed to help address this question.

The analyses discussed above showed

that the top row of the TOC removal

matrix needed to be lowered by 5.0

percentage points to enable 90 percent

of systems within the row to achieve the

required TOC removal without

unreasonable coagulant doses. Analysis

also showed the TOC removal

percentages contained in the two lower

rows of the TOC removal matrix

accurately reflected the TOC removal 90

percent of these systems could remove.

EPA believes the final TOC removal

matrix, which includes the adjustments

to the top row mentioned above,

accurately reflects the TOC removal that

90 percent of the systems affected by the

rule could practically achieve.

Commenters questioned why systems

that meet the DBP Stage 1 MCLs for

TTHM and HAA5 must still practice

enhanced coagulation. The enhanced

coagulation treatment technique is

designed to remove DBP precursor

material to help reduce the risks posed

by DBPs. Also, EPA believes that

enhanced coagulation would reduce the

number of systems switching to

alternative disinfectants, which was a

goal of the Reg. Neg. Committee. EPA

believes that even if systems are meeting

the MCLs, an additional risk reduction

benefit can be achieved through removal

of DBP precursor material at a relatively

low cost to the system. Therefore,

systems that meet the MCLs must still

practice enhanced coagulation to

decrease the risks posed by DBPs in

general.

The Agency received numerous

comments on the 1994 proposal that

expressed doubt regarding the definition

of the PODR. Specifically, the

commenters stated that the accuracy of

the slope criterion (0.3 mg/L TOC

removed per 10 mg/L coagulant added)

for determining the PODR was not

supported with adequate data. The data

developed since the proposal and the

corresponding analysis demonstrate that

the slope criterion accurately predicts

the PODR. The analyses discussed

above showed that there is a particular

relationship between SUVA and the

slope criterion, namely, that they both

predict the PODR at the same point of

the TOC removal versus coagulant dose

curve. Since SUVA is a very good

predictor of the humic fraction of TOC,

which is the fraction preferentially

removed by enhanced coagulation, and

the PODR predicted by SUVA and the

slope criterion agree, EPA believes the

slope criterion of 0.3 mg/L TOC removal

per 10 mg/L of coagulant addition

accurately predicts the PODR.

The majority of commenters did not

support requiring the use of bench-scale

filtration as part of the Step 2 enhanced

coagulation procedure. The commenters

generally believed that using filtration at

bench scale is of limited value because

the great majority of TOC is removed via

sedimentation, not through filtration.

Additionally, some commentors felt that

attempting to replicate full-scale

filtration at bench scale can contain

inherent inaccuracy. EPA generally

agrees that a Step 2 filtration procedure

should not be required. The Agency

believes that most of the TOC removed

by conventional treatment plants is

removed in the sedimentation basin

rather than in the filters. Therefore,

requiring a bench-scale filtration

procedure as part of Step 2 testing will

not increase the accuracy of the

procedure or its value to the treatment

technique implementation. Accordingly,

today’s final rule does not require the

use of a bench scale filtration procedure

during Step 2 enhanced coagulation

testing. Detailed guidance on

conducting the Step 2 testing will be

provided in the Guidance Manual for

Enhanced Coagulation and Enhanced

Precipatative Softening.

Commenters expressed varied

opinions regarding the frequency of

Step 2 testing. Several commenters

stated that the rule should not set a

minimum testing frequency, but that it

should be left to State discretion based

on source water characteristics. Other

commenters believed a minimum of

quarterly monitoring should be required

with a provision for more frequent

testing to address source water quality

events. EPA believes that Step 2 testing

frequency should be related to seasonal

and other variations in source water

quality as these variations may

influence the amount of TOC removal

the treatment plant can achieve.

Accordingly, EPA recommends that

systems utilizing the Step 2 procedure

for compliance perform Step 2 testing

quarterly for one year after the effective

data of the rule. The system may then

apply to the State to reduce testing to a

minimum of once per year. If the State

does not approve the request for

reduced testing frequency, the system

must continue to test quarterly.
69416 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

E. Predisinfection Disinfection Credit

1. Today’s Rule

Today’s rule does not impose any

constraints on the ability of systems to

practice predisinfection and take

microbial inactivation credit for

predisinfection to meet the disinfection

requirements of the SWTR. Utilities are

free to take disinfection credit for

predisinfection, regardless of the

disinfectant used, for disinfection that

occurs after the last point the source

water is subject to surface water run-off

and prior to the first customer.

2. Background and Analysis

The 1994 proposed Stage 1 DBPR

(EPA,1994a) discouraged the use of

disinfectants prior to precursor

(measured as TOC) removal by not

allowing compliance credit for the

SWTR’s disinfection requirements to be

taken prior to removal of a specified

percentage of TOC. The proposed

IESWTR options were intended to

include microbial treatment

requirements to prevent increases in

microbial risk due to the loss of

predisinfection credit. These options

were to be implemented simultaneously

with the Stage 1 DBPR. The purpose of

not allowing predisinfection credit was

to maximize removal of organic

precursors (measured as TOC) prior to

the addition of a disinfectant, thus

lowering the formation of DBPs.

Many drinking water systems use

preoxidation to control a variety of

water quality problems such as iron and

manganese, sulfides, zebra mussels,

Asiatic clams, and taste and odor. The

1994 proposed rule did not preclude the

continuous addition of oxidants to

control these problems. However, the

proposed regulation, except under a few

specific conditions, did not allow credit

for compliance with disinfection

requirements prior to TOC removal.

Analysis supporting the proposed rule

concluded that many plants would be

able to comply with the Stage 1 MCLs

for THMs and HAA5 of 0.080 mg/L and

0.060 mg/L, respectively, by reductions

in DBP levels as a result of reduced

disinfection practice in the early stages

of treatment. Also, enhanced

coagulation and enhanced softening

were thought to lower the formation of

other unidentified DBPs as well. The

1994 proposal assumed that addition of

disinfectant prior to TOC removal

would initiate DBP formation through

contact of the chlorine with the TOC,

effectively eliminating the value of

enhanced coagulation for DBP

reduction. Finally, the analysis

underlying the 1994 proposed

elimination of the preoxidation credit

assumed that the addition of

disinfectant was essentially ‘‘mutually

exclusive’’ to the goal of reducing DBP

formation by the removal of TOC. As

discussed below, new data developed

since 1994 suggest this may not be the

case.

Reasons for Disinfectant Use. In order

to obtain information on the impact that

disallowing predisinfection would have

on utilities’ disinfection practices, a

survey was sent out to ICR utilities to

obtain information on their current

predisinfection practices. The results of

the survey of 329 surface water

treatment plants indicated that 80

percent (263) of these plants use

predisinfection for one or more reasons.

The survey indicated that the majority

of the plants using predisinfection were

doing so for multiple reasons. However,

the main reason reported for

predisinfection was microbial

inactivation. Algae control, taste and

odor control, and inorganic oxidation,

in that order, were the next most

frequently cited reasons for practicing

predisinfection. Seventy-seven percent

of plants that predisinfected reported

that their current levels of Giardia

lamblia inactivation would be lowered

if predisinfection was discontinued and

no subsequent additional disinfection

was added to compensate for change in

practice. Eighty-one percent of plants

that predisinfected would have to make

major capital investments to make up

for the lost logs of Giardia lamblia

inactivation. For example, to maintain

the same level of microbial protection

currently afforded, construction to

provide for additional contact time or

use of a different disinfectant might be

needed if predisinfection credit was

eliminated.

In addition to the ICR mail survey,

results from EPA’s Comprehensive

Performance Evaluations (CPE) from 307

PWSs (4 to 750 mgd) reported that 71%

of the total number of plants used

predisinfection and 93% of those that

predisinfected used two or three

disinfectant application points during

treatment.

Based on the above information, EPA

believes that predisinfection is used by

a majority of PWSs for microbial

inactivation, as well as other drinking

water treatment objectives. Therefore,

disallowing predisinfection credit could

influence systems to make changes in

treatment to comply with the

disinfection requirements of the SWTR

or to maintain current levels of

microbial inactivation.

Impact of Point of Chlorination on

DBP Formation. The results of a study

by Summers et al. (1997) indicate that

practicing enhanced coagulation, while

simultaneously maintaining

prechlorination, can still result in

decreased DBP formation (especially for

TOX and TTHM). Greater benefits are

realized by moving the point of

chlorination to post-rapid mixing or

further downstream for HAA5 control,

and to mid-flocculation or postsedimentation for TOX and TTHM

control. These data show that the

assumption made in the 1994 proposal,

namely that application of any

disinfectant prior to TOC removal

would critically effect DBP formation,

was not accurate. The data indicate that

simultaneous employment of enhanced

coagulation and predisinfection does

not necessarily mean that DBP

formation cannot be substantially

controlled (see EPA 1997b for detailed

analysis).

Impact on Softening Plants. In order

to obtain additional information on the

current TOC removals being achieved

by softening plants, a survey was sent to

all the ICR softening utilities (49 plants)

requesting that they fill out a single page

of information with yearly average,

maximum and minimum values for

multiple operating parameters for each

softening plant. The survey showed that

in spite of the fact that 78 percent of

softening plants are using free chlorine

for at least a portion of their

disinfection, 90 percent of plants are

currently meeting an 80 μg/L MCL level

for TTHMS. All the softening plants

reported average HAA5 levels below 60

μg/L. Without predisinfection credit,

these plants may have to provide

disinfection contact time after

sedimentation, which could mean

significantly increasing the free chlorine

contact time to make up for a shortened

detention time.

3. Summary of Comments

Most commenters stated that the

proposed elimination of predisinfection

would result in many plants not being

able to maintain existing levels of

disinfection or comply with the SWTR

disinfection requirements without

making significant compensatory

changes in their disinfection practice.

Commenters were concerned that

without predisinfection the level of

microbial risk their customers were

exposed to could significantly increase,

and that eliminating microbial

inactivation credit for predisinfection to

comply with the SWTR might influence

utilities to abandon predisinfection to

more easily comply with the TTHM and

HAA5 MCLs. EPA agrees with this

concern and therefore the final rule has

been modified from the proposal to

allow predisinfection credit.
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69417

F. Requirements for Systems to Use

Qualified Operators

EPA believes that systems that must

make treatment changes to comply with

requirements to reduce the

microbiological risks and risks from

disinfectants and disinfection

byproducts should be operated by

personnel who are qualified to

recognize and react to problems.

Therefore, in today’s rule, the Agency is

requiring that all systems regulated

under this rule be operated by an

individual who meets State specified

qualifications, which may differ based

on size and type of the system. Subpart

H systems already are required to be

operated by qualified operators under

the provisions of the SWTR (40 CFR

141.70(c)). Current qualification or

certification programs developed by the

States should, in many cases, be

adequate to meet this requirement for

Subpart H systems. Also, States must

maintain a register of qualified

operators.

EPA encourages States which do not

already have operator certification

programs in effect to develop such

programs. The Reg. Neg. Committee and

TWG believed that properly trained

personnel are essential to ensure safer

drinking water. States with existing

operator certification programs may

wish to update their programs for

qualifying operators under the SWTR. In

these cases, States may wish to indicate

that their operator certification

programs are being developed in

accordance with EPA’s new guidelines.

G. Analytical Methods

1. Today’s Rule

Chlorine (Free, Combined, and Total).

Today’s rule approves four methods for

measuring free, combined, and total

chlorine to determine compliance with

the chlorine MRDL (using either free or

total chlorine) and chloramines MRDL

(using either combined or total

chlorine): ASTM Method D1253–86

(ASTM, 1996), Standard Methods 4500–

Cl D (APHA, 1995), 4500–Cl F (APHA,

1995), and 4500–Cl G (APHA, 1995).

Additionally, this rule approves two

methods for measuring total chlorine to

determine compliance with the chlorine

MRDL and chloramines MRDL:

Standard Methods 4500–Cl E (APHA,

1995) and 4500–Cl I (APHA, 1995). The

rule also contains an additional method

for measuring free chlorine to determine

compliance with the chlorine MRDL:

Standard Method 4500–Cl H (APHA,

1995).

Chlorine Dioxide. Today’s rule

approves two methods for determining

compliance with the chlorine dioxide

MRDL: Standard Methods 4500–ClO2 D

(APHA, 1995) and 4500–ClO2 E (APHA

1995). EPA did not approve Standard

Method 4500–ClO2 C (APHA, 1995),

which was included in the 1994

proposed rule. The Agency determined,

in concurrence with the majority of

commenters on this issue, that Standard

Method 4500–ClO2 C is outdated and

inaccurate in comparison to chlorine

dioxide methods approved in today’s

rule and is inadequate for compliance

monitoring.

TTHM. Today’s rule approves three

methods for determining compliance

with the TTHM MCL: EPA Methods

502.2 (EPA, 1995), 524.2 (EPA, 1995),

and 551.1 (EPA, 1995).

HAA5. Today’s rule approves three

methods for determining compliance

with the HAA5 MCL: EPA Methods

552.1 (EPA, 1992) and 552.2 (EPA,

1995) and Standard Method 6251B

(APHA, 1995).

Bromate. Today’s rule approves a

method for determining compliance

with the bromate MCL: EPA Method

300.1 (EPA, 1997e). EPA has

demonstrated this method to be capable

of quantifying bromate at the MCL of 10

μg/L under a wide range of solution

conditions. EPA did not approve EPA

Method 300.0 (EPA, 1993b) for bromate

analysis, although this method was

included for analysis of bromate in the

1994 proposed rule. As stated in the

proposed rule, EPA Method 300.0 is not

sensitive enough to measure bromate at

the MCL established in today’s rule.

EPA Method 300.1 was developed

subsequent to the proposed rule in order

to provide a method with adequate

sensitivity to assess bromate

compliance.

Chlorite. Today’s rule approves two

methods for determining compliance

with the chlorite MCL: EPA Methods

300.0 (EPA, 1993b) and 300.1 (EPA,

1997e). As described elsewhere in

today’s rule, chlorite compliance

analyses are made on samples taken in

the distribution system during monthly

monitoring, or during additional

distribution system monitoring as

required. Today’s rule establishes the

following method for daily monitoring

of chlorite: Standard Method 4500-ClO2

E (APHA, 1995), amperometric titration.

As stated elsewhere in today’s rule,

daily monitoring of chlorite is

conducted on samples taken at the

entrance to the distribution system.

Commenters supported the use of

amperometric titration as a feasible

method for daily monitoring of chlorite.

TOC. Today’s Rule approves three

methods for TOC analysis: Standard

Methods 5310 B, 5310 C, and 5310 D,

as published in the Standard Methods

19th Edition Supplement (APHA, 1996).

EPA believes that all of these methods

can achieve the precision and detection

level necessary for compliance

determinations required in today’s rule

when the quality control (QC)

procedures contained in the method

descriptions and this rule are followed.

However, while any of these methods

may be used, EPA advises that a

consistent method be employed for all

measurements in order to reduce the

impact of possible instrument bias.

In accordance with the concerns of

commenters, today’s rule requires

certain QC procedures for TOC analyses

in addition to those contained in the

method descriptions. These additional

QC steps are designed to increase the

integrity of the analysis and have been

found to be effective in data collection

under the ICR. Filtration of samples

prior to TOC analysis is not permitted,

as this could result in removal of

organic carbon. Where turbidity

interferes with TOC analysis, samples

should be homogenized and, if

necessary, diluted with organic-free

reagent water. TOC samples must either

be analyzed or must be acidified to

achieve pH less than 2.0 by minimal

addition of phosphoric or sulfuric acid

as soon as practical after sampling, not

to exceed 24 hours. Samples must be

analyzed within 28 days.

SUVA (Specific Ultraviolet

Absorbance). Today’s rule establishes

SUVA as an alternative criterion for

demonstrating compliance with TOC

removal requirements contained in

today’s rule. SUVA is a calculated

parameter defined as the UV absorption

at 254 nm (UV254) (measured as m¥1)

divided by the DOC concentration

(measured as mg/L). If the UV

absorption is first determined in units of

cm¥1, the SUVA equation is multiplied

by 100 to convert to m¥1, as shown

below:

SUVA = 100 (cm/m) [UV254 (cm¥1)/DOC

(mg/L)]

Two separate analytical methods are

necessary to make this measurement:

UV254 and DOC. Today’s rule approves

three methods for DOC analysis:

Standard Methods 5310 B, 5310 C, and

5310 D, as published in the Standard

Methods 19th Edition Supplement

(APHA, 1996); and approves Standard

Method 5910 B (APHA, 1995) for UV254

analysis.

The final rule contains QC steps for

the SUVA analyses that are required in

addition to those mandated in the

method descriptions. These

requirements were developed in

response to comments solicited by EPA

in the 1997 DBP NODA (EPA, 1997b)

and are as follows:
69418 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

—sample acquisition (DOC and UV254

samples used to determine a SUVA

value must be taken at the same time

and at the same location. SUVA must

be determined on water prior to the

addition of disinfectants/oxidants.)

—sample preservation (DOC samples

must either be analyzed or must be

acidified to achieve pH less than 2.0

by minimal addition of phosphoric or

sulfuric acid as soon as practical after

sampling, not to exceed 48 hours. The

pH of UV254 samples may not be

adjusted.)

—holding times (DOC samples must be

analyzed within 28 days of sampling.

UV254 samples must be analyzed as

soon as practical after sampling, not

to exceed 48 hours.)

—filtration (Prior to analysis, UV254 and

DOC samples must be filtered through

a 0.45 μm pore-diameter filter. DOC

samples must be filtered prior to

acidification.)

—background concentrations in the

filtered blanks (Water passed through

the filter prior to filtration of the

sample must serve as the filtered

blank. This filtered blank must be

analyzed using procedures identical

to those used for analysis of the

samples and must meet the following

criteria: TOC <0.5 mg/L.)

Bromide. Today’s rule approves the

following two methods for monitoring

bromide: EPA Methods 300.0 (EPA,

1993b) and 300.1 (EPA, 1997e).

Alkalinity. Today’s rule approves

three methods for measuring alkalinity:

ASTM Method D1067–92B (ASTM,

1994), Standard Method 2320 B (APHA,

1995), and Method I–1030–85 (USGS,

1989).

pH. Today’s rule requires the use of

methods that have been previously

approved in § 141.23(k) for

measurement of pH.

Approved analytical methods are

summarized in Table III–2.

TABLE III–2.—APPROVED ANALYTICAL METHODS

Analyte EPA method Standard method Other

Chlorine (free, combined, total) ................................................................................... ........................ 4500–Cl D ASTM D1253–8.

........................ 4500–Cl F

........................ 4500–Cl G

(Total) .......................................................................................................................... ........................ 4500–Cl E

........................ 4500–Cl I

(Free) ........................................................................................................................... ........................ 4500–Cl H

Chlorine Dioxide .......................................................................................................... ........................ 4500–ClO2 D

........................ 4500–ClO2 E

TTHM ........................................................................................................................... 502.2

524.2

551.1

HAA5 ........................................................................................................................... 552.1 625l B

552.2

Bromate ....................................................................................................................... 300.1

Chlorite (monthly) ........................................................................................................ 300.0

300.1

(Daily) .......................................................................................................................... ........................ 4500–ClO2 E

TOC/DOC .................................................................................................................... ........................ 5310 B

........................ 5310 C

........................ 5310 D

UV254 ............................................................................................................................ ........................ 5910 B

Bromide ....................................................................................................................... 300.0

300.1

Alkalinity ....................................................................................................................... ........................ 2320 B ASTM D1067–

92B.

USGS I–1030–

85.

pH ................................................................................................................................ 150.1 4500–H+B ASTM D1293–84.

150.2

2. Background and Analysis

Chlorine (Free, Combined, and Total).

In the 1994 proposed rule, EPA

included all Standard Methods for

analysis of free, combined, and total

chlorine that were approved in today’s

rule.

Chlorine Dioxide. The 1994 proposed

rule included the same three methods

for analyzing chlorine dioxide (ClO2)

that are approved under the SWTR and

ICR regulations. Two of these methods,

Standard Methods 4500.ClO2 C (APHA,

1992) and 4500.ClO2 E (APHA, 1992),

are amperometric methods. The third

proposed method was Standard Method

4500.ClO2 D (APHA, 1992), a

colorimetric test using the color

indicator N,N-diethyl-pphenylenediamine (DPD).

TTHM. The 1994 proposed rule

included three methods for the analysis

of TTHMs. They were EPA Methods

502.2, 524.2, and 551. In 1995, EPA

Method 551 was revised to EPA Method

551.1, rev. 1.0 (EPA, 1995), which was

approved for ICR monitoring under 40

CFR 141.142.

EPA Method 551.1 has several

improvements upon EPA Method 551.

The use of sodium sulfate is strongly

recommended over sodium chloride for

the MTBE extraction of DBPs. This

change was in response to a report

indicating elevated recoveries of some

brominated DBPs due to bromide

impurities in the sodium chloride (Xie,

1995). Other changes to EPA Method

551.1 include a buffer addition to

stabilize chloral hydrate, elimination of

the preservative ascorbic acid, and

modification of the extraction procedure

to minimize the loss of volatile analytes.

The revised method requires the use of

surrogate and other quality control

standards to improve the precision and

accuracy of the method.

HAA5. The 1994 proposed rule

included two methods for the analysis

of five haloacetic acids—EPA Method

552.1 (EPA, 1992) and Standard Method

6233B (APHA, 1992). Both methods use

capillary column gas chromatographs

equipped with electron capture
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69419

detectors. The two methods differ in the

sample preparation steps. EPA Method

552.1 uses solid phase extraction disks

followed by an acidic methanol

derivitization. Standard Method 6233B

is a small volume liquid-liquid (micro)

extraction with methyl-t-butyl ether,

followed by a diazomethane

derivitization. Following the proposed

rule, Standard Method 6233B was

revised and renumbered 6251B (APHA,

1995) to include bromochloroacetic

acid, for which a standard was not

commercially available in 1994.

Recognizing these improvements, EPA

approved Standard Method 6251B for

analysis under the ICR (40 CFR Part 141

or EPA, 1996a). Several commenters

requested that the revised and

renumbered method, Standard Method

6251B, also be approved for the analysis

of haloacetic acids under the Stage 1

DBPR.

In 1995 EPA published a third

method for HAAs, EPA Method 552.2

(EPA, 1995), and subsequently approved

it for HAA analysis under the 1996 ICR

(40 CFR Part 141 or EPA, 1996a). EPA

Method 552.2 is an improved method,

combining the micro extraction

procedure of Standard Method 6233B

with the acidic methanol derivitization

procedure of EPA Method 552.1. It is

capable of analyzing nine HAAs.

Bromate. The 1994 proposed rule

required systems that use ozone to

monitor for bromate ion. EPA proposed

EPA Method 300.0 (EPA, 1993b) for the

analysis of bromate and chlorite ions.

However, at the time of the proposal,

EPA was aware that EPA Method 300.0

was not sensitive enough to measure

bromate ion concentration at the

proposed MCL of 10 μg/L. EPA

recognized that modifications to the

method would be necessary to increase

the method sensitivity. Studies at that

time indicated that changes to the

injection volume and the eluent

chemistry would decrease the detection

limit below the MCL. Many commenters

to the 1994 proposal agreed that EPA

Method 300.0 was not sensitive enough

to determine compliance with a MCL of

10 μg/L bromate ion, given that MCLs

are typically set at 5 times the minimum

detection levels (MDLs).

Following the proposal, EPA

improved EPA Method 300.0 and

renumbered it as EPA Method 300.1

(EPA, 1997b). EPA Method 300.1

specifies a new, high capacity ion

chromatography (IC) column that is

used for the analysis of all anions listed

in the method, instead of requiring two

different columns as specified in EPA

Method 300.0. The new column has a

higher ion exchange capacity that

improves chromatographic resolution

and minimizes the potential for

chromatographic interferences from

common anions at concentrations

10,000 times greater than bromate ion.

For example, quantification of 5.0 μg/L

bromate is feasible in a matrix

containing 50 mg/L chloride.

Minimizing the interferences permits

the introduction of a larger sample

volume to yield method detection limits

in the range of 1–2 μg/L.

In the 1997 DBPR NODA (EPA,

1997b), EPA discussed EPA Method

300.1 and projected that by using it

laboratories would be able to quantify

bromate with the accuracy and

precision necessary for compliance

determination with an MCL of 10 μg/L.

Although there would be a limited

number of laboratories that would be

qualified to do such analyses, EPA

determined that there should be

adequate laboratory capacity for

bromate ion compliance monitoring by

the time the rule becomes effective.

Chlorite. The proposed rule required

systems using chlorine dioxide for

disinfection or oxidation to perform

monthly monitoring for chlorite ion in

the distribution system. EPA designated

EPA Method 300.0 (ion

chromatography) for chlorite analysis.

EPA considered other methods using

amperometric and potentiometric

techniques but decided that only the ion

chromatography method (EPA Method

300.0) would produce results with the

accuracy and precision needed for

determining compliance. Subsequent to

the proposed rule, EPA Method 300.0

was improved in order to achieve lower

detection limits for bromate ion and

renumbered as EPA Method 300.1.

TOC. To satisfy requirements of the

Stage 1 DBPR, the 1994 proposed rule

directed that a TOC analytical method

should have a detection limit of at least

0.5 mg/L and a reproducibility of ± 0.1

mg/L over a range of 2 to 5 mg/L TOC.

The proposed rule included two

methods for analyzing TOC: Standard

Methods 5310 C, which is the

persulfate-ultraviolet oxidation method,

and 5310 D, the wet-oxidation method

(APHA, 1992). These methods were

selected because, according to data

published in Standard Methods (APHA

1992), they could achieve the necessary

precision and detection limit. Standard

Method 5310 B, the high-temperature

combustion method, was considered but

not proposed because it was described

in Standard Methods (1992, APHA) as

having a detection limit of 1 mg/L. The

proposal stated that if planned

improvements to the instrumentation

used in Standard Method 5310 B were

successful, the next version would be

considered for promulgation. Revisions

of Standard Methods 5310 B, C, and D

were published in Standard Methods

19th Edition Supplement (APHA, 1996).

The revised version of Standard Method

5310 B recognized the capacity of

certain high temperature instruments to

achieve detection limits below 1 mg/L

using this method.

SUVA (Specific Ultraviolet

Absorbance). SUVA analytical methods

were not addressed in the 1994

proposed rule because SUVA had not

been developed and proposed as a

compliance parameter for TOC removal

requirements at that time. The analytical

methods and associated QC procedures

for DOC and UV254 approved in today’s

rule are those on which the Agency

solicited comment in the 1997 DBPR

NODA (EPA, 1997b).

Bromide. The 1994 proposed rule

included EPA Method 300.0 for analysis

of bromide. EPA believed that the

working range of this method

adequately covered the requirements

proposed for bromide monitoring. As

described above, EPA developed

Method 300.1 for improved bromate

analysis subsequent to the proposed

rule. EPA Method 300.1 can also

effectively measure bromide at the

concentration of 50 μg/L, required in

today’s rule for reduced monitoring of

bromate.

Alkalinity. The proposed rule

included all methods approved by EPA

for measuring alkalinity. These methods

have all been approved in today’s rule.

3. Summary of Comments

Following is a discussion of major

comments on the analytical methods

requirements of the Stage 1 DBPR.

Chlorine. A commenter to the 1994

proposal recommended approval of

ASTM method D1253–86. EPA

determined that this method is

equivalent to Standard Method 4500–Cl

D, and has approved this method in

today’s rule.

Chlorine Dioxide. EPA received

comments on the proposed rule

detailing weaknesses of the methods

selected to calculate ClO2. Commenters

pointed out that other halogenated

species, such as free chlorine,

chloramines, and chlorite, as well as

common metal ions (e.g. copper,

manganese, chromate) will interfere

with these methods. Additionally,

where these methods determine

concentrations by difference, they are

potentially inaccurate and subject to

propagation of errors. Commenters

specifically criticized Standard Method

4500–ClO2 C (APHA 1995),

amperometric method I, which was

characterized as outdated and

inaccurate, and stated that Standard
69420 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

Method 4500–ClO2 E (APHA 1995),

amperometric method II, is a

substantially better method.

Consequently, in the 1997 DBP NODA,

EPA requested comment on removing

Standard Method 4500–ClO2 C from the

list of approved methods for the

analysis of chlorine dioxide for

compliance with the MRDL.

Comments on the 1997 DBPR NODA

favored eliminating Standard Method

4500.ClO2 C as an approved method for

ClO2 compliance analysis. EPA does not

approve this method in today’s rule.

EPA recognizes that the two methods

approved for ClO2 monitoring under

today’s rule are subject to interferences.

However, EPA believes that these

methods can be used effectively to

indicate compliance with the ClO2

MRDL when the quality control

procedures contained in the method

descriptions are followed. Several

commenters also encouraged EPA to

approve a more sensitive and specific

method for ClO2 analysis, and suggested

alternative methods including Acid

Chrome Violet K, Lissamine Green B,

and Chlorophenol Red. While EPA

supports the development of improved

analytical methods for chlorine dioxide,

the Agency believes that at this time the

methods suggested by commenters have

not gone through the necessary

performance validation processes to

warrant their approval for compliance

monitoring.

Bromate. In the 1994 proposed rule,

EPA discussed the fact that the current

version of EPA Method 300.0 was not

sensitive enough to measure bromate

ion concentrations at the proposed MCL

and requested comment on

modifications to EPA Method 300.0 to

improve its sensitivity. In the 1997

NODA, EPA presented EPA Method

300.1 and requested comment on

replacing EPA Method 300.0 with EPA

Method 300.1 for the analysis of

bromate.

Commenters agreed that EPA Method

300.1 is a more sensitive method than

EPA Method 300.0 for low level bromate

analysis and the majority suggested that

EPA Method 300.1 be the approved

method for bromate analysis. One

commenter requested that

interlaboratory round-robin testing be

conducted before EPA Method 300.1 is

accepted for Stage 1 DBPR compliance

monitoring. EPA considers

interlaboratory round-robin testing of

EPA Method 300.1 to be unnecessary

because this method is essentially an

improvement of EPA Method 300.0

which is already approved. EPA Method

300.1 primarily makes use of a superior

analytical column to achieve increased

sensitivity for bromate analysis.

Moreover, the efficacy of EPA Method

300.1 in a wide range of sample

matrices is demonstrated by the

performance validation data contained

in the published method description.

Based on a review of all the public

comments, EPA is approving EPA

Method 300.1 for bromate analysis in

today’s rule.

Chlorite. EPA solicited comment in

the 1997 DBPR NODA on approving

EPA Method 300.1, in addition to EPA

Method 300.0, for compliance analysis

of chlorite. The majority of commenters

on this issue favored approval of both

methods and today’s rule establishes

both for determining compliance with

the chlorite MCL.

In the 1994 proposed rule, EPA

requested comment on changing

monitoring requirements for chlorite to

reflect concern about potential acute

health effects. Several commenters

stated that daily monitoring of chlorite

would be feasible if an amperometric

analytical method could be used.

Commenters suggested that daily

amperometric analyses for chlorite be

conducted on samples taken from the

entrance to the distribution system, and

that weekly or monthly analyses using

ion chromatography still be required as

a check, because ion chromatography is

a more accurate analytical method.

Commenters noted that daily

monitoring for chlorite would provide

improved operational control of plants

and reduce the likelihood of systems

incurring compliance violations.

Today’s rule establishes amperometric

titration (Standard Method 4500–ClO2

E) for daily analyses of chlorite samples

taken at the entrance to the distribution

system, along with monthly (or

quarterly if reduced, or additional as

required), analyses by ion

chromatography (EPA Methods 300.0

and 300.1) of chlorite samples taken

from within the distribution system.

EPA believes that the ion

chromatography method, rather than the

amperometric method, should be used

for making chlorite compliance

determinations in the distribution

system due to its greater accuracy.

However, the amperometric method is

sufficient for the purposes of daily

monitoring at the entrance to the

distribution system, which are to

significantly aid in proper operational

control of a treatment plant and to

indicate when distribution system

testing is appropriate. For this reason,

only the ion chromatographic methods

(EPA Method 300.0 and 300.1), and not

the amperometric titration methods, are

approved in today’s rule for determining

compliance with the chlorite MCL.

A minority of commenters on this

issue suggested that the DPD method

(Standard Method 4500–ClO2 D (APHA

1995)) be approved for daily monitoring

of chlorite ion levels. EPA has

determined that the accuracy and

precision of the DPD method (Standard

Method 4500–ClO2 D) in the

measurement of chlorite are

substantially worse than with Standard

Method 4500–ClO2 E, and are

insufficient for this method to be used

for daily monitoring of chlorite. As a

consequence, EPA has not approved the

DPD method for chlorite monitoring in

today’s rule.

TOC. EPA received several comments

on the 1994 proposal requesting

approval of Standard Method 5310 B for

TOC compliance analysis. Commenters

stated that newer instrumentation could

achieve a detection limit of 0.5 mg/L

TOC using this method. Following the

publication of a revised version of

Method 5310 B in Standard Methods

19th Edition Supplement (APHA 1996)

which recognized the capacity of some

combustion based TOC analyzers to

achieve detection limits below 1 mg/L,

EPA requested comment on approving

Standard Method 5310 B, along with

Standard Methods 5310 C and 5310 D,

for the analysis of TOC in the 1997

DBPR NODA.

The majority of commenters on TOC

analysis urged EPA to approve all three

methods. Commenters were concerned,

though, that because these three

methods employ different processes to

oxidize organic carbon to carbon

dioxide, results from different TOC

analyzers could vary to a degree that is

of regulatory significance. Specifically,

the efficiency of oxidation of large

organic particles or very large organic

molecules such as tannins, lignins, and

humic acids may be lower with

persulfate based instruments (APHA

1996). Although available data

comparing different TOC methods is

limited, one study observed a persulfate

catalytic oxidation technique to

underestimate the TOC concentration

measured by a high temperature

catalytic oxidation technique by 3–6%

on stream water and soil water samples

(Kaplan, 1992). Standard Methods

recommends checking the oxidation

efficiency of the instrument with model

compounds representative of the sample

matrix, because many factors can

influence conversion of organic carbon

to carbon dioxide (APHA 1996).

EPA believes that the potential

regulatory impact of small disparities in

oxidation efficiencies between different

TOC analyzers is minor. Studies using

PE samples indicate that for instruments

calibrated in accordance with the
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69421

procedures specified in Standard

Methods (APHA, 1996), the magnitude

of measurement error due to analytical

discrepancies between instruments will

typically be less than the measurement

uncertainty attributed to a particular

instrument (EPA, 1994c). In addition,

EPA anticipates that most systems will

use a consistent method for TOC

analyses and that this will assist in

minimizing the importance of

instrument bias. This practice was

suggested by several commenters.

Commenters also suggested that EPA

implement a formal certification process

for laboratories measuring TOC. Some

commenters recommended that EPA

require a laboratory approval process for

TOC measurements under the Stage 1

DBPR that is similar to what is required

under the ICR. EPA requires that TOC

analyses be conducted by a party

approved by EPA or the State but not

that TOC measurements be subject to

the same laboratory certification

procedures required for the analysis of

DBPs. However, today’s rule contains

QC requirements for TOC analyses

which are in addition to those in

Standard Methods. These additional QC

procedures pertain to sample

preservation and holding time, and have

been found to be effective for TOC

analyses under the ICR.

SUVA. In the 1997 DBPR NODA, EPA

solicited comment on a range of issues

dealing with the determination of SUVA

including: analytical methods,

sampling, sample preparation, filter

types, pH, interferences to UV, high

turbidity waters, quality control, and

other issues that should be addressed.

The Agency requested comment on

approving Standard Method 5910 B for

measuring UV254 and Standard Methods

5310 B, C, and D, for measuring DOC.

In requesting comment on filtration,

EPA noted that filtration is necessary

prior to both UV254 and DOC analyses in

order to eliminate particulate matter and

separate the operationally defined

dissolved organic matter (based on a

0.45 μm-pore-diameter cut-off).

However, filtration can also corrupt

samples through adsorption of

carbonaceous material onto the filter or

its desorption from it (APHA 1996). In

addition, EPA requested comment on

requiring that UV254 and DOC analyses

be measured from the same sample

filtrate.

The majority of commenters on SUVA

analytical methods recommended that

EPA approve Standard Methods 5310 B,

C, and D, for DOC analysis and Standard

Method 5910 B for UV254 analysis. EPA

has approved these methods in today’s

rule. In addition, commenters stressed

the importance of sample preparation,

especially filtration, in the measurement

of DOC and observed that sufficient

washing of filters prior to filtration of

samples is critical to preventing

contamination of the samples by organic

carbon from the filters. Several

comments on the 1997 DBPR NODA

expressed opposition to a requirement

that UV254 and DOC analyses be made

on the same sample filtrate.

Commenters stated that this is

impractical because UV analyses are

often conducted at the treatment plant

while DOC analyses are typically run

off-site. Commenters also noted that

DOC samples should be acid preserved

whereas pH adjustment of samples for

UV254 analysis is improper.

Today’s rule establishes that samples

for DOC and UV254 analyses must be

filtered through a 0.45 μm-porediameter filter. EPA does not have

specific requirements on the type of

filter that is used, provided it has a 0.45

μm pore-diameter, but will provide

guidance on this issue in the Guidance

Manual for Enhanced Coagulation. This

manual will be available for public

review after promulgation of the Stage 1

DBPR. Today’s rule addresses filter

washing prior to analysis by requiring

that water passed through the filter prior

to filtration of the sample serve as the

filtered blank. The filtered blank must

be analyzed using procedures identical

to those used for analysis of the samples

and must meet the following criteria:

TOC < 0.5 mg/L. These criteria are the

maximum allowable background

concentrations specified for these

analyses under the ICR. In the Guidance

Manual for Enhanced Coagulation, EPA

will furnish instructions on sample

handling and filter washing to assist

systems in achieving acceptable field

reagent blanks.

Filtration of samples for DOC analysis

must be done prior to acid preservation,

as stipulated in today’s rule. This is

necessary because acidification of the

sample to pH < 2 can cause substantial

precipitation of dissolved organic

species. Because biological activity will

rapidly alter the DOC of a sample that

has not been preserved, EPA requires

that DOC samples be acidified to pH <

2.0 within 48 hours of sampling.

Consequently, filtration of DOC samples

must be done within 48 hours in order

to allow acid preservation within this

time period. The pH of UV254 samples

may not be adjusted. Today’s rule places

a maximum holding time from sampling

to analysis of 2 days for UV254 samples

and 28 days for DOC samples. These

holding times are the same as those

approved for ICR data collection.

Because the filtration procedures for

UV254 and DOC samples are largely

identical, EPA anticipates that most

systems will find it economical when

determining SUVA to filter one sample.

The filtrate would then be split into two

portions, one of which would be used

for UV analysis while the other would

be acid preserved and used for DOC

analysis. However, EPA has not

included a requirement that the DOC

and UV254 analyses used in the SUVA

determination be made on the same

sample filtrate. Instead, EPA requires

that DOC and UV254 samples used to

determine a SUVA value must be taken

at the same time and at the same

location.

In the 1997 DBPR NODA, EPA also

observed that because disinfectants/

oxidants (chlorine, ozone, chlorine

dioxide, potassium permanganate)

typically reduce UV254 without

substantially impacting DOC, raw water

SUVA should be determined on water

prior to the application of disinfectants/

oxidants. If disinfectants/oxidants are

applied in raw-water transmission lines

upstream of the plant, then raw water

SUVA should be based on a sample

collected upstream of the point of

disinfectant/oxidant addition. For

determining settled-water SUVA, if the

plant applies disinfectants/oxidants

prior to the settled water sample tap,

then settled-water SUVA should be

determined in jar testing. No

commenters were opposed to these

provisions and today’s rule requires that

samples used for SUVA determinations

be taken from water prior to the

addition of any oxidants/disinfectants.

A few commenters stated that SUVA

should not be subject to rigorous

analytical procedures because the

application of SUVA in this rule is

based on a relationship which is largely

empirical (i.e. correlations between

SUVA and TOC removal by

coagulation). EPA recognizes the

empirical nature of this relationship and

the variance it has displayed in studies.

Regulations, however, must address

specific SUVA values if SUVA is to

serve as an alternative compliance

parameter. For compliance with these

regulations to be meaningful, SUVA

must be determined accurately.

Consequently, today’s rule requires

certain QC procedures in the DOC and

UV254 analyses that are used to calculate

SUVA.

Today’s rule establishes the removal

of 10 mg/L magnesium hardness (as

CaCO3) as an alternative performance

criterion that systems practicing

enhanced softening can use to

demonstrate compliance with the

treatment technique requirement for

TOC removal. However, EPA did not

propose methods for the analysis of
69422 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

magnesium in drinking water and

therefore the final rule does not contain

any approved methods for magnesium.

EPA expects to propose magnesium

analytical methods to be used for

compliance monitoring under the Stage

1 DBPR by the end of 1998.

4. Performance Based Measurement

Systems

On October 6, 1997, EPA published a

Document of the Agency’s intent to

implement a Performance Based

Measurement System (PBMS) in all of

its programs to the extent feasible (EPA,

1997f). The Agency is currently

determining the specifics steps

necessary to implement PBMS in its

programs and preparing an

implementation plan. Final decisions

have not yet been made concerning the

implementation of PBMS in drinking

water programs. However, EPA is

currently evaluating what relevant

performance characteristics should be

specified for monitoring methods used

in the drinking water programs under a

PBMS approach to ensure adequate data

quality. EPA would then specify

performance requirements in its

regulations to ensure that any method

used for determination of a regulated

analyte is at least equivalent to the

performance achieved by other

currently approved methods. EPA

expects to publish its PBMS

implementation strategy for water

programs in the Federal Register by the

end of calendar year 1998.

Once EPA has made its final

determinations regarding

implementation of PBMS in programs

under the Safe Drinking Water Act, EPA

would incorporate specific provisions of

PBMS into its regulations, which may

include specification of the performance

characteristics for measurement of

regulated contaminants in the drinking

water program regulations.

H. Monitoring Requirements

1. Today’s Rule

Today’s rule establishes monitoring

requirements to support implementation

of the enhanced coagulation and

enhanced softening treatment

technique, implementation of new

MCLs for TTHM, HAA5, bromate, and

chlorite, and implementation of MRDLs

for chlorine, chloramines, and chlorine

dioxide. Monitoring for DBPs,

disinfectant residuals, and TOC must be

conducted during normal operating

conditions. Failure to monitor in

accordance with the monitoring plan is

a monitoring violation. Where

compliance is based on a running

annual average of monthly or quarterly

samples or averages and the system’s

failure to monitor makes it impossible to

determine compliance with MCLs or

MRDLs, this failure to monitor will be

treated as a violation.

Tables III–3 and III–4 below

summarize routine and reduced

monitoring requirements of today’s rule.

TABLE III–3.—ROUTINE MONITORING REQUIREMENTS 1

Requirement

(reference) Location for sampling Large surface systems 2

Small surface systems 2Large ground water

systems 3

Small ground water

systems 3

TOC and Alkalinity

(141.132(d)(1)).

Source Water 4 .......... 1sample/month/plant 3 1 sample/month/

plant3.

NA ............................. NA.

Only required for

plants with conventional filtration treatment.

TTHMs and HAA5

(141.132(b)(1)(i)).

25% in dist sys at

max res time, 75%

at dist sys representative locations.

4/plant/quarter ........... 1/plant/quarter5 ......... 1/plant/quarter 6 ......... 1/plant/year 5,6

at maximum residence time.at maximum residence time.at maximum residence time.

if pop.<500, then 1/

plant/yr 8.

during warmest

month.

during warmest

month.

Bromate 7

(141.132(b)(3)(i)).

Dist sys entrance

point.

1/month/trt plant

using O3.

1/month/trt plant

using O3.

1/month/trt plant

using O3.

1/month/trt plant

using O3.

Chlorite8 (daily)

(141.132(b)(2)(i)(A)).

Dist sys entrance

point.

Daily/trt plant using

CIO2.

Daily/trt plant using

CIO2.

Daily/trt/plant using

CIO2.

Chlorite8 (monthly)

141.132(b)(2)(i)(B)).

Dist sys: 1 near first

cust, 1 in dist sys

middle, 1 at max

res time.

3 sample set/month .. 3 sample set/month .. 3 sample set/month .. 3 sample set/month.

Chlorine and

chloramines

(141.132(c)(1)(i)).

Same points as total

coliform in TCR.

Same times as total

coliform in TCR.

Same times as total

coliform in TCR.

Same times as total

coliform in TCR.

Same times as total

coliform in TCR.

Chlorine dioxide8

(141.132(c)(2)(i)).

Dist sys entrance

point.

Daily/trt plant using

CIO2.

Daily/trt plant using

CIO2.

Daily/trt plant using

CIO2.

Daily/trt plant using

CIO.

1Samples must be taken during representative operating conditions. Provisions for reduced monitoring shown elsewhere.

2 Large surface (subpart H) systems serve 10,000 or more persons. Small surface (subpart H) systems serve fewer than 10,000 persons.

3 Large systems using ground water not under the direct influence of surface water serve 10,000 or more persons. Small systems using

ground water not under the direct influence of surface water serve fewer than 10,000 persons. 4Subpart H systems which use conventional filtration treatment (defined in section 141.2) must monitor 1) source water TOC prior to any treatment and 2) treated TOC at the same time; these two samples are called paired samples. Systems must take a source water alkalinity sample at

the same time. 5 If the annual monitoring result exceeds the MCL, the system must increase monitoring frequency to 1/plant/quarter. Compliance determinations will be based on the running annual average of quarterly monitoring results.
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69423

6 Multiple wells drawing water from a single aquifer may, with State approval, be considered one treatment plant for determining the minimum

number of samples. 7Only required for systems using ozone for oxidation or disinfection.

8Only required for systems using chlorine dioxide for oxidation or disinfection. Additional chlorite monitoring required if daily sample exceeds

MCL. Additional chlorine dioxide monitoring requirements apply if any chlorine dioxide sample exceeds the MRDL.

TABLE III–4.—REDUCED MONITORING REQUIREMENTS 1

Requirement

(reference)

Location for reduced

sampling Reduced monitoring frequency and prerequisites 2

TOC and Alkalinity

(141.132(d)(2)).

Paired samples 3 ......... Subpart H systems-reduced to 1 paired sample/plant/quarter if 1) avg TOC < 2.0 mg/l for 2

years or 2) avg TOC < 1.0 mg/l for 1 year.

TTHMs and HAA5s

(141.132(b)(1)(ii)).

In dist sys at point with

max res time.

Monitoring cannot be reduced if subpart H system source water TOC > 4.0 mg/l.

Subpart H systems serving 10,000 or more-reduced to 1/plant/qtr if 1) system has completed

at least 1 yr of routine monitoring and 2) both TTHM and HAA5 running annual averages

are no more than 40 μg/l and 30 μg/l, respectively.

Subpart H systems serving <10,000 and ground water systems 4 serving 10,000 or more-reduced to 1/plant/yr if 1) system has completed at least 1 yr of routine monitoring and 2)

both TTHM and HAA5 running annual averages are no more than 40 μg/l and 30 μg/l, respectively. Samples must be taken during month of warmest water temperature. Subpart H

systems serving <500 may not reduce monitoring to less than 1/plant/yr.

Groundwater systems 6 serving<10,000-reduced to 1/plant/3yr if 1) system has completed at

least 2 yr of routine monitoring and both TTHM and HAA5 running annual averages are no

more than 40 μg/l and 30 μg/l, respectively or 2) system has completed at least 1 yr of

routine monitoring and both TTHM and HAA5 annual samples are no more than 20 μg/l

and 15 μg/l, respectively. Samples must be taken during month of warmest water temperature.

Bromate 5

(141.132(b)(3)(ii)).

Dist sys entrance point 1/qtr/trt plant using O3, if system demonstrates 1) avg raw water bromide <0.05 mg/l (based

on annual avg of monthly samples).

Chlorite 6

(141.132(b)(2)(iii)).

Dist sys: 1 near first

cust, 1 in dist sys

middle, 1 at max res

time.

Systems may reduce routine distribution system monitoring from monthly to quarterly if the

chlorite concentration in all samples taken in the distribution system is below 1.0 mg/L for a

period of one year; 3 samples per quarter.

Chlorine, chlorine dioxide 6, chloramines

(141.132(c)(2)(ii) and

(c)(2)(iii).

NA ............................... Monitoring may not be reduced.

1Samples must be taken during representative operating conditions. Provisions for routine monitoring shown elsewhere.

2 Requirements for cancellation of reduced monitoring are found in the regulation.

3Subpart H systems which use conventional filtration treatment (defined in Section 141.2) must monitor 1) source water TOC prior to any treatment and 2) treated TOC before continuous disinfection (except that systems using ozone followed by biological filtration may sample after biological filtration) at the same time; these two samples are called paired samples. 4 Multiple wells drawing water from a single aquifer may, with State approval, be considered one treatment plant for determining the minimum

number of samples. 5Only required for systems using ozone for oxidation or disinfection.

6Only required for systems using chlorine dioxide for oxidation or disinfection.

The formation rate of DBPs is affected

by type and amount of disinfectant

used, water temperature, pH, amount

and type of precursor material in the

water, and the length of time that water

remains in the treatment and

distribution systems. For this reason,

today’s rule specifies the points in the

distribution system (and, in some cases,

the time) where samples must be taken.

For purposes of this regulation, multiple

wells drawing raw water from a single

aquifer may, with State approval, be

considered one plant for determining

the minimum number of samples.

TTHM and HAA5. Any system may

take samples in excess of the required

frequency. In such cases, at least 25

percent of all samples collected each

quarter must be taken at locations

within the distribution system that

represent the maximum residence time

of the water in the system. The

remaining samples must be taken at

locations representative of at least

average residence time in the

distribution system.

Subpart H Systems Serving 10,000 or

More People. Routine Monitoring: CWSs

and NTNCWSs using surface water (or

ground water under direct influence of

surface water) (Subpart H systems) that

treat their water with a chemical

disinfectant and serve 10,000 or more

people must routinely take four water

samples each quarter for both TTHMs

and HAA5 for each treatment plant in

the system. At least 25 percent of the

samples must be taken at the point of

maximum residence time in the

distribution system. The remaining

samples must be taken at representative

points in the distribution system. This

monitoring frequency is the same as the

frequency required under the current

TTHM rule (§ 141.30).

Reduced Monitoring: To qualify for

reduced monitoring, systems must meet

certain prerequisites (see Figure III–1).

Systems eligible for reduced monitoring

may reduce the monitoring frequency

for TTHMs and HAA5 to one sample per

treatment plant per quarter. Systems on

a reduced monitoring schedule may

remain on that reduced schedule as long

as the average of all samples taken in

the year is no more than 0.060 mg/L for

TTHM and 0.045 mg/L for HAA5.

Systems that do not meet these levels

must revert to routine monitoring in the

quarter immediately following the

quarter in which the system exceeded

0.060 mg/L for TTHM or 0.045 mg/L for

HAA5. Additionally, the State may

return a system to routine monitoring at

the State’s discretion.
69424 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

FIGURE III–1.—ELIGIBILITY FOR REDUCED TTHM AND HAA5 MONITORING: GROUND WATER SYSTEMS SERVING 10,000

OR MORE PEOPLE AND SUBPART H SYSTEMS SERVING 500 OR MORE PEOPLE

Ground water systems serving 10,000 or more people, and Subpart H systems serving 500 or more people, may reduce monitoring of TTHMs

and HAA5 if they meet all of the following conditions:

—The annual average for TTHMs is no more than 0.040 mg/L.

—The annual average for HAA5 is no more than 0.030 mg/L.

—At least one year of routine monitoring has been completed.

—Annual average source water TOC level is no more than 4.0 mg/L prior to treatment (applies to Subpart H systems only).

Compliance Determination: A public

water system (PWS) is in compliance

with the MCL when the running annual

arithmetic average of quarterly averages

of all samples, computed quarterly, is

less than or equal to the MCL. If the

running annual average computed for

any quarter exceeds the MCL, the

system is out of compliance.

Subpart H Systems Serving 500 to

9,999 People. Routine Monitoring:

Systems are required to take one water

sample each quarter for each treatment

plant in the system. Samples must be

taken at the point of maximum

residence time in the distribution

system.

Reduced Monitoring: To qualify for

reduced monitoring, systems must meet

certain prerequisites (see Figure III–1).

Systems eligible for reduced monitoring

may reduce the monitoring frequency

for TTHMs and HAA5 to one sample per

treatment plant per year. Sample must

be taken at a distribution system

location reflecting maximum residence

time and during the month of warmest

water temperature. Systems on a

reduced monitoring schedule may

remain on that reduced schedule as long

as the average of all samples taken in

the year is no more than 0.060 mg/L for

TTHM and 0.045 mg/L for HAA5.

Systems that do not meet these levels

must revert to routine monitoring in the

quarter immediately following the

quarter in which the system exceeded

0.060 mg/L for TTHM or 0.045 mg/L for

HAA5. Additionally, the State may

return a system to routine monitoring at

the State’s discretion.

Compliance Determination: A PWS is

in compliance with the MCL for TTHM

and HAA5 when the annual average of

all samples, taken that year, is less than

or equal to the MCL. If the average for

these samples exceeds the MCL, the

system is out of compliance.

Subpart H Systems Serving Fewer

than 500 People. Routine Monitoring:

Subpart H systems serving fewer than

500 people are required to take one

sample per year for each treatment plant

in the system. The sample must be taken

at the point of maximum residence time

in the distribution system during the

month of warmest water temperature. If

the annual sample exceeds the MCL, the

system must increase monitoring to one

sample per treatment plant per quarter,

taken at the point of maximum

residence time in the distribution

system.

Reduced Monitoring: These systems

may not reduce monitoring. Systems on

increased monitoring may return to

routine monitoring if the annual average

of quarterly samples is no more than

0.060 mg/L for TTHM and 0.045 mg/L

for HAA5.

Compliance Determination: A PWS is

in compliance when the annual sample

(or average of annual samples, if

additional sampling is conducted) is

less than or equal to the MCL. If the

annual sample exceeds the MCL, the

system must increase monitoring to one

sample per treatment plant per quarter.

If the running annual average of the

quarterly samples then exceeds the

MCL, the system is out of compliance.

Ground Water Systems Serving 10,000

or More People. Routine Monitoring:

CWSs and NTNCWSs using only ground

water sources not under the direct

influence of surface water that treat

their water with a chemical disinfectant

and serve 10,000 or more people are

required to take one water sample each

quarter for each treatment plant in the

system. Samples must be taken at points

that represent the maximum residence

time in the distribution system.

Reduced Monitoring: To qualify for

reduced monitoring, systems must meet

certain prerequisites (see Figure III–1).

Systems eligible for reduced monitoring

may reduce the monitoring frequency to

one sample per treatment plant per year.

Sample must be taken at a distribution

system location reflecting maximum

residence time and during the month of

warmest water temperature. Systems on

a reduced monitoring schedule may

remain on that reduced schedule as long

as the average of all samples taken in

the year is no more than 0.060 mg/L for

TTHM and 0.045 mg/L for HAA5.

Systems that do not meet these levels

must revert to routine monitoring in the

quarter immediately following the

quarter in which the system exceeded

0.060 mg/L for TTHM or 0.045 mg/L for

HAA5. Additionally, the State may

return a system to routine monitoring at

the State’s discretion.

Compliance Determination: A PWS is

in compliance with the MCL when the

running arithmetic annual average of

quarterly averages of all samples,

computed quarterly, is less than or

equal to the MCL. If the running annual

average for any quarter exceeds the

MCL, the system is out of compliance.

Ground Water Systems Serving Fewer

than 10,000 People Routine Monitoring:

CWSs and NTNCWSs using only ground

water sources not under the direct

influence of surface water that treat

their water with a chemical disinfectant

and serve fewer than 10,000 people are

required to sample once per year for

each treatment plant in the system. The

sample must be taken at the point of

maximum residence time in the

distribution system during the month of

warmest water temperature. If the

sample (or the average of annual

samples if more than one sample is

taken) exceeds the MCL, the system

must increase monitoring to one sample

per treatment plant per quarter.

Reduced Monitoring: To qualify for

reduced monitoring, systems must meet

certain prerequisites (see Figure III–2).

Systems eligible for reduced monitoring

may reduce the monitoring frequency

for TTHMs and HAA5 to one sample per

three-year monitoring cycle. Sample

must be taken at a distribution system

location reflecting maximum residence

time and during the month of warmest

water temperature. Systems on a

reduced monitoring schedule may

remain on that reduced schedule as long

as the average of all samples taken in

the year is no more than 0.060 mg/L for

TTHM and 0.045 mg/L for HAA5.

Systems that do not meet these levels

must resume routine monitoring.

Systems on increased monitoring may

return to routine monitoring if the

annual average of quarterly samples is

no more than 0.060 mg/L for TTHM and

0.045 mg/L for HAA5.

Compliance Determination: A PWS is

in compliance when the annual sample

(or average of annual samples) is less

than or equal to the MCL.
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69425

FIGURE III–2.—ELIGIBILITY FOR REDUCED TTHM AND HAA5 MONITORING: GROUND WATER SYSTEMS SERVING FEWER

THAN 10,000 PEOPLE

Systems using ground water not under the direct influence of surface water that serve fewer than 10,000 people may reduce monitoring for

TTHMs and HAA5 if they meet either of the following conditions:

1. The average of two consecutive annual samples for TTHMs is no more than 0.040 mg/L, the average of two consecutive annual samples for

HAA5 is no more than 0.030 mg/L, and at least two years of routine monitoring has been completed.

2. The annual sample for TTHMs is no more than 0.020 mg/L, the annual sample for HAA5 is no more than 0.015 mg/L, and at least one year

of routine monitoring has been completed.

Chlorite. Routine Monitoring: CWSs

and NTNCWSs using chlorine dioxide

for disinfection or oxidation are

required to conduct sampling for

chlorite both daily at the entrance to the

distribution system and monthly within

the distribution system. Additional

distribution system monitoring may be

required, and distribution system

monitoring may be reduced if certain

conditions are met. This monitoring is

described below.

Routine Monthly Monitoring—

Systems are required to take a three

sample set each month in the

distribution system. One sample must

be taken at each of the following

locations: (1) as close as possible to the

first customer, (2) in a location

representative of average residence time,

and (3) as close as possible to the end

of the distribution system (reflecting

maximum residence time in the

distribution system). As described

elsewhere in this document, all samples

taken in the distribution system must be

analyzed by ion chromatography

(Methods 300.0 and 300.1).

Routine Daily Monitoring—Systems

must take one sample each day at the

entrance to the distribution system. As

described elsewhere in this document

(section III.G), samples taken at the

distribution system entrance may be

analyzed by amperometric titration

(Method 4500–ClO2 E). If the chlorite

MCL is exceeded at the entrance to the

distribution system, the system is not

out of compliance. However, the system

must carry out addition monitoring as

described in the following paragraph.

Additional Monitoring: On any day

when the chlorite concentration

measured at the entrance to the

distribution system exceeds the chlorite

MCL (1.0 mg/L), the system is required

to take a three sample set in the

distribution system on the following

day, at the locations specified for

routine monthly monitoring. If the

system is required to conduct

distribution system monitoring as a

result of having exceeded the chlorite

MCL at the entrance to the distribution

system, and the average of the three

samples taken in the distribution system

is below 1.0 mg/L, the system will have

satisfied its routine monthly monitoring

requirement for that month. Further

distribution system monitoring will not

be required in that month unless the

chlorite concentration at the entrance to

the distribution system again exceeds

1.0 mg/L.

Reduced Monitoring: Systems may

reduce routine distribution system

monitoring for chlorite from monthly to

quarterly if the chlorite concentration in

all samples taken in the distribution

system is below 1.0 mg/L for a period

of one year and the system has not been

required to conduct any additional

monitoring. Systems that qualify for

reduced monitoring must continue to

conduct daily monitoring at the

entrance to the distribution system. If

the chlorite concentration at the

entrance to the distribution system

exceeds 1.0 mg/L, the system must

resume routine monthly monitoring.

Compliance Determination: A PWS is

out of compliance with the chlorite

MCL when the arithmetic average

concentration of any three sample set

taken in the distribution system is

greater than 1.0 mg/L.

Bromate. Routine Monitoring: CWSs

and NTNCWSs using ozone for

disinfection or oxidation are required to

take at least one sample per month for

each treatment plant in the system using

ozone. The sample must be taken at the

entrance to the distribution system

when the ozonation system is operating

under normal conditions.

Reduced Monitoring: Systems may

reduce monitoring from monthly to

once per quarter if the system

demonstrates that the annual average

raw water bromide concentration is less

than 0.05 mg/L, based upon monthly

measurements for one year.

Compliance Determination: A PWS is

in compliance if the running annual

arithmetic average of samples,

computed quarterly, is less than or

equal to the MCL.

Chlorine. Routine Monitoring: As a

minimum, CWSs and NTNCWSs must

measure the residual disinfectant level

(as either free chlorine or total chlorine)

at the same points in the distribution

system and at the same time as total

coliforms, as specified in § 141.21.

Subpart H systems may use the results

of residual disinfectant concentration

sampling done under the SWTR

(§ 141.74(b)(6)(i) for unfiltered systems,

§ 141.74(c)(3)(i) for systems that filter)

in lieu of taking separate samples.

Reduced Monitoring: Monitoring for

chlorine may not be reduced.

Compliance Determination: A PWS is

in compliance with the MRDL when the

running annual arithmetic average of

monthly averages of all samples,

computed quarterly, is less than or

equal to the MRDL. Notwithstanding the

MRDL, operators may increase residual

chlorine levels in the distribution

system to a level and for a time

necessary to protect public health to

address specific microbiological

contamination problems (e.g., including

distribution line breaks, storm runoff

events, source water contamination, or

cross-connections).

Chloramines. Routine Monitoring: As

a minimum, CWSs and NTNCWSs must

measure the residual disinfectant level

(as either total chlorine or combined

chlorine) at the same points in the

distribution system and at the same time

as total coliforms, as specified in

§ 141.21. Subpart H systems may use the

results of residual disinfectant

concentration sampling done under the

SWTR (§ 141.74(b)(6) for unfiltered

systems, § 141.74(c)(3) for systems that

filter) in lieu of taking separate samples.

Reduced Monitoring: Monitoring for

chloramines may not be reduced.

Compliance Determination: A PWS is

in compliance with the MRDL when the

running annual arithmetic average of

monthly averages of all samples,

computed quarterly, is less than or

equal to the MRDL. Notwithstanding the

MRDL, operators may increase residual

chloramine levels in the distribution

system to a level and for a time

necessary to protect public health to

address specific microbiological

contamination problems (e.g., including

distribution line breaks, storm runoff

events, source water contamination, or

cross-connections).

Chlorine Dioxide Routine Monitoring:

CWSs, NTNCWSs, and TNCWSs must

monitor for chlorine dioxide only if

chlorine dioxide is used by the system

for disinfection or oxidation. If

monitoring is required, systems must

take daily samples at the entrance to the
69426 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

distribution system. If the MRDL (0.8

mg/L) is exceeded, the system must

conduct additional monitoring.

Additional Monitoring: If any daily

sample taken at the entrance to the

distribution system exceeds the MRDL,

the system is required to take three

additional samples in the distribution

system on the next day. Samples must

be taken at the following locations.

Systems using chlorine as a residual

disinfectant and operating booster

chlorination stations after the first

customer—These systems must take

three samples in the distribution

system: one as close as possible to the

first customer, one in a location

representative of average residence time,

and one as close as possible to the end

of the distribution system (reflecting

maximum residence time in the

distribution system).

Systems using chlorine dioxide or

chloramines as a residual disinfectant or

chlorine as a residual disinfectant and

not operating booster chlorination

stations after the first customer—These

systems must take three samples in the

distribution system as close as possible

to the first customer at intervals of not

less than six hours.

Reduced Monitoring: Monitoring for

chlorine dioxide may not be reduced.

Compliance Determination: Acute

violations—If any daily sample taken at

the entrance to the distribution system

exceeds the MRDL and if, on the

following day, one or more of the three

samples taken in the distribution system

exceeds the MRDL, the system will be

in acute violation of the MRDL and

must issue the required acute public

notification. Failure to monitor in the

distribution system on the day following

an exceedance of the chlorine dioxide

MRDL shall also be considered an acute

MRDL violation.

Nonacute violations—If any two

consecutive daily samples taken at the

entrance to the distribution system

exceed the MRDL, but none of the

samples taken in the distribution system

exceed the MRDL, the system will be in

nonacute violation of the MRDL. Failure

to monitor at the entrance to the

distribution system on the day following

an exceedance of the chlorine dioxide

MRDL shall also be considered a

nonacute MRDL violation.

Important Note: Unlike chlorine and

chloramines, the MRDL for chlorine

dioxide may not be exceeded for short

periods of time to address specific

microbiological contamination

problems.

TOC. Routine Monitoring: CWSs and

NTNCWSs which use conventional

filtration treatment must monitor each

treatment plant water source for TOC on

a monthly basis, with samples taken in

both the source water prior to any

treatment and in the treated water no

later than the point of combined filter

effluent turbidity monitoring. At the

same time, systems must monitor for

source water alkalinity.

Reduced Monitoring: Subpart H

systems with an average treated water

TOC of less than 2.0 mg/L for two

consecutive years, or less than 1.0 mg/

L for one year, may reduce monitoring

for both TOC and alkalinity to one

paired sample per plant per quarter.

Compliance Determination:

Compliance criteria for TOC are

dependent upon a variety of factors and

is discussed elsewhere in this rule.

2. Background and Analysis

The monitoring requirements in

today’s rule are the same as those in the

1994 proposed rule, with the exception

of requirements for bromide monitoring

and chlorite.

Bromide Monitoring for Reduced

Bromate Monitoring. The 1994 proposal

included a provision for reduced

bromate monitoring for utilities with

source water bromide concentrations

less than 0.05 mg/L. EPA believes there

is a very small likelihood that systems

using ozone will exceed the bromate

MCL if source water bromide

concentrations are below this level. The

provision did not specify a bromide

monitoring frequency, however. Today’s

rule allows utilities to reduce bromate

monitoring from monthly to once per

quarter if the system demonstrates,

based on representative monthly

samples over the course of a year, that

the average raw water bromide

concentration is less than 0.05 mg/L.

Chlorite Monitoring. The proposed

rule required treatment plants using

chlorine dioxide to monitor for chlorite

ion by taking a three sample set in the

distribution system, once per month,

and to analyze these samples using ion

chromatography. However, the proposal

states that after the Negotiating

Committee had agreed to the above

monitoring scheme for chlorite at its last

meeting in June, 1993, EPA’s Reference

Dose Committee met and determined a

different toxicological endpoint for

chlorite, based on the identification of

neurobehavioral effects. In light of this

finding, EPA asserted that it did not

believe the proposed monthly

monitoring requirement for chlorite was

sufficiently protective of public health.

Following the proposed rule, EPA

acquired additional information on

chlorite toxicity, including the results of

a two-generation study sponsored by the

CMA. This additional information,

discussed elsewhere in this document

(III.A.7), supported EPA’s finding of

neurobehavioral health effects resulting

from chlorite, along with the rationale

for daily monitoring at the entrance to

the distribution system as a trigger for

further compliance monitoring in the

distribution system.

3. Summary of Comments

TOC. Many commenters expressed

confusion regarding the raw and

finished water TOC monitoring scheme

and their relationship to compliance

calculations. Commenters noted,

correctly, that changes in alkalinity and

TOC level can move the utility to a

different box of the TOC removal

matrix, and questioned whether this

would affect requisite monitoring. As in

the proposal, moving to a different box

of the matrix will not affect monitoring

requirements. Utilities are required to

take a minimum of one paired (raw and

finished water) TOC sample per month.

Commenters were also concerned that

the TOC monitoring provisions would

limit their ability to take additional TOC

samples for operational control. This

concern is unfounded; EPA

recommends in the Enhanced

Coagulation and Enhanced Precipitative

Softening Guidance Manual that

utilities take as many TOC samples as

necessary to maintain proper

operational control. EPA also

recommends that TOC compliance

samples, as opposed to operational

samples, be taken on a constant

schedule or be identified one month

prior to the samples being taken. This

will allow utilities to take numerous

operational samples and still provide for

unbiased compliance sampling. Systems

may use their sampling plans for this

purpose.

Chlorite. In the proposal, EPA

solicited comment on changing the

frequency and location of chlorite

monitoring in consideration of potential

acute health effects. Commenters stated

that daily monitoring of chlorite would

be feasible if amperometric titration

were allowed as an analytical method.

Commenters recommended that daily

amperometric analyses for chlorite be

conducted on samples taken from the

entrance to the distribution system, and

that weekly or monthly analyses using

ion chromatography still be required as

a check since ion chromatography is a

more accurate analytical method.

Several comments stated that daily

monitoring for chlorite would improve

operational control of plants and

decrease the probability of a PWS

exceeding the chlorite MCL in the

distribution system. However,

commenters requested that if daily

monitoring for chlorite were to be
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69427

required, a provision for reduced

chlorite monitoring be included as well.

In response to these comments,

today’s rule requires treatment plants

using chlorine dioxide to conduct daily

monitoring for chlorite by taking one

sample at the entrance to the

distribution system. This sample may be

measured using amperometric titration

(Standard Method 4500-ClO 2 E).

Treatment plants are also required to

take a three sample set from the

distribution system once per month, as

was proposed in 1994. In addition,

today’s rule requires that on any day

that the concentration of chlorite

measured at the distribution system

entrance exceeds the MCL, the

treatment plant must take a three

sample set in the distribution system on

the following day. All samples taken in

the distribution system must be

analyzed by ion chromatography

(Method 300.0 or 300.1).

EPA recommends that treatment

plants keep chlorite levels below 1.0

mg/L and believes that if treatment

plants exceed the MCL in finished

water, immediate distribution system

testing is warranted to ensure that

chlorite levels are below 1.0 mg/L. EPA

has not, however, changed the

compliance determination for chlorite

from the 1994 proposed rule.

Compliance is still based on the average

of three sample sets taken in the

distribution system. The results of daily

monitoring do not serve as a compliance

violation; rather, they can only trigger

immediate distribution system

monitoring. Moreover, if the treatment

plant is required to take distribution

system samples by the results of daily

monitoring and the average chlorite

concentration in the three distribution

system samples is below the MCL, then

that sampling will meet the treatment

plant’s requirement for routine monthly

monitoring in the distribution system

for that month. Today’s rule also

includes a provision for reduced

chlorite monitoring. Treatment plants

may reduce routine distribution system

monitoring for chlorite from monthly to

quarterly if the chlorite concentration in

all samples both at the entrance to the

distribution system and within the

distribution system are below 1.0 mg/L

for a period of one year.

In summary, after review of all public

comments and associated data, EPA

believes that these provisions for

chlorite monitoring will be both feasible

for treatment plants and provide a level

of protection to public health

commensurate with the toxic effects

associated with chlorite.

I. Compliance Schedules

1. Today’s Rule

Today’s action establishes revised

compliance deadlines for States to adopt

and for public water systems to

implement the requirements in this

rulemaking. Central to the

determination of these deadlines are the

principles of simultaneous compliance

between the Stage 1 DBPR and the

corresponding rules (Interim Enhanced

Surface Water Treatment Rule, Long

Term Enhanced Surface Water

Treatment Rule, and Ground Water

Rule) to ensure continued microbial

protection, and minimization of riskrisk tradeoffs. These deadlines also

reflect new legislative provisions

enacted as part of 1996 SDWA

amendments. Section 1412 (b)(10) of the

SDWA as amended provides PWSs must

comply with new regulatory

requirements 36 months after

promulgation (unless EPA or a State

determines that an earlier time is

practicable or that additional time up to

two years is necessary for capital

improvements). In addition, Section

1413(a)(1) provides that States have 24

instead of the previous 18 months from

promulgation to adopt new drinking

water standards.

Applying the 1996 SDWA

Amendments to today’s action, this

rulemaking provides that States have

two years from promulgation to adopt

and implement the requirements of this

regulation. Simultaneous compliance

will be achieved as follows.

Subpart H water systems covered by

today’s rule that serve a population of

10,000 or more generally have three

years from promulgation to comply with

all requirements of this rule. In cases

where capital improvements are needed

to comply with the rule, States may

grant such systems up to an additional

two years to comply. These deadlines

were consistent with those for the

IESWTR.

Subpart H systems that serve a

population of less than 10,000 and all

ground water systems will be required

to comply with applicable Stage 1 DBPR

requirements within five years from

promulgation. Since the Long Term

Enhanced Surface Water Treatment Rule

(LT1) requirements that apply to

systems under 10,000 and the Ground

Water Rule are scheduled to be

promulgated two years after today’s rule

or in November 2000, the net result of

this staggered deadline is that these

systems will be required to comply with

both Stage 1 DBPR and LT1/GWR

requirements three years after

promulgation of LT1/GWR at the same

end date of November 2003. For reasons

discussed in more detail below, EPA

believes this is both consistent with the

requirements of section 1412(b)(10) as

well as with legislative history affirming

the Reg. Neg. objectives of simultaneous

compliance and minimization of riskrisk tradeoff.

2. Background and Analysis

The background, factors, and

competing concerns that EPA

considered in developing the

compliance deadlines in today’s rule are

explained in detail in both the Agency’s

IESWTR and Stage 1 DBPR November

1997 NODAs. As explained in those

NODAs, EPA identified four options to

implement the requirements of the 1996

SDWA Amendments. The requirements

outlined above reflect the fourth option

that EPA requested comment upon in

November 1997.

By way of background, the SDWA

1996 Amendments affirmed several key

principles underlying the M–DBP

compliance strategy developed by EPA

and stakeholders as part of the 1992

regulatory negotiation process. First,

under Section 1412(b)(5)(A), Congress

recognized the critical importance of

addressing risk/risk tradeoffs in

establishing drinking water standards

and gave EPA the authority to take such

risks into consideration in setting MCL

or treatment technique requirements.

The technical concerns and policy

objectives underlying M/DBP risk/risk

tradeoffs are referred to in the initial

sections of today’s rule and have

remained a key consideration in EPA’s

development of appropriate compliance

requirements. Second, Congress

explicitly adopted the phased M–DBP

regulatory development schedule

developed by the Negotiating

Committee. Section 1412(b)(2)(C)

requires that the M/DBP standard

setting intervals laid out in EPA’s

proposed ICR rule be maintained even

if promulgation of one of the M–DBPRs

is delayed. As explained in the 1997

NODA, this phased or staggered

regulatory schedule was specifically

designed as a tool to minimize risk/risk

tradeoff. A central component of this

approach was the concept of

‘‘simultaneous compliance’’, which

provides that a PWS must comply with

new microbial and DBP requirements at

the same time to assure that in meeting

a set of new requirements in one area,

a facility does not inadvertently increase

the risk (i.e., the risk ‘‘tradeoff’’) in the

other area.

A complicating factor that EPA took

into account in developing today’s

deadlines is that the SDWA 1996

Amendments changed two statutory

provisions that elements of the 1992
69428 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

Negotiated Rulemaking Agreement were

based upon. The 1994 Stage 1 DBPR and

ICR proposals provided that 18 months

after promulgation large PWS would

comply with the rules and States would

adopt and implement the new

requirements. As noted above, Section

1412(b)(10) of the SDWA as amended

now provides that drinking water rules

shall become effective 36 months after

promulgation (unless the Administrator

determines that an earlier time is

practicable or that additional time for

capital improvements is necessary—up

to two years). In addition, Section

1413(a)(1) now provides that States have

24 instead of the previous 18 months to

adopt new drinking water standards that

have been promulgated by EPA.

Today’s compliance deadline

requirements reflect the principle of

simultaneous compliance and the

concern with risk/risk tradeoffs. Subpart

H systems serving a population of at

least 10,000 will be required to comply

with the key provisions of this rule on

the same schedule as they will be

required to comply with the parallel

requirements of the accompanying

IESWTR that is also included in today’s

Federal Register.

With regard to subpart H systems

serving fewer than 10,000, EPA believes

that providing a five year compliance

period under Stage 1 DBPR is

appropriate and warranted under

section 1412(b)(10), which expressly

allows five years where necessary for

capital improvements. As discussed in

more detail in the 1997 IESWTR NODA,

capital improvements require, of

necessity, preliminary planning and

evaluation. An essential prerequisite of

such planning is a clear understanding

of final compliance requirements that

must be met. In the case of the staggered

M/DBP regulatory schedule established

as part of the 1996 SDWA Amendments,

LT1 microbial requirements for systems

under 10,000 are required to be

promulgated two years after the final

Stage 1 DBPR. As a result, small systems

will not even know what their final

combined compliance obligations are

until promulgation of the LT 1 rule.

Thus, an additional two year period

reflecting the two year Stage 1 DBPR/LT

1 regulatory development interval

established by Congress is required to

allow for the preliminary planning and

design steps which are inherent in any

capital improvement process.

In the case of ground water systems,

the statutory deadline for promulgation

of the GWR is May 2002. However, EPA

intends to promulgate this rule by

November 2000, in order to allow three

years for compliance and still ensure

simultaneous compliance by ground

water systems with the Stage 1 DBPR

and the GWR. As in the case of subpart

H systems serving fewer than 10,000,

system operators will not know until

November 2000 what the final

compliance requirements for both rules

are. EPA thus believes it appropriate to

grant the additional two years for

compliance with the Stage 1 DBPR

allowed by the statute.

EPA has been very successful in

meeting all of the new statutory

deadlines and is on track for the LT1

Rule and GWR. While EPA fully intends

to meet the schedule discussed earlier,

if those rules are delayed the Agency

will evaluate all available options to

protect against unacceptable risk-risk

trade-offs. Part of this effort is the

extensive outreach to systems already

underway to fully inform water supplies

of the likely elements in the upcoming

rules. In addition, EPA would consider

including provisions for streamlined

variance and/or exemption processing

in these rules if they were delayed, in

order to enhance State flexibility in

ensuring that compliance with the Stage

1 DBPR is not required before the

corresponding microbial protection rule.

Under today’s Stage 1 DBPR, EPA has

already provided small subpart H

systems and ground water systems the

two-year extension for capital

improvements since these systems will

not know with certainty until November

2000 if capital improvements will be

needed for simultaneous compliance

with the Stage 1 DBPR and LT1/GWR.

States considering whether to grant a

two-year capital improvement extension

for compliance with the GWR or LT1

will also need to consider the impact of

such extensions on compliance with

today’s rule, given that a similar

extension for capital improvement has

already been provided in the initial

compliance schedule for the Stage 1

DBPR. EPA believes, however, that

these systems will generally not require

extensive capital improvements that

take longer than three years to install to

meet Stage 1 DBPR, GWR, and LT1

requirements, or will require no capital

improvements at all. However if needed,

EPA will work with States and utilities

to address systems that require time

beyond November 2003 to comply. This

strategy may include exemptions.

In addition, EPA will provide

guidance and technical assistance to

States and systems to facilitate timely

compliance with both DBP and

microbial requirements. EPA will

request comment on how best to do this

when the Agency proposes the

LTESWTR and GWR.

3. Summary of Comments

Commenters were in general

agreement that the compliance deadline

strategy contained in the fourth option

of the 1997 NODA did the best job of

complying with the requirements to

1996 SDWA Amendments and meeting

the objectives of the 1993 Reg. Neg.

Agreement that Congress affirmed as

part of the 1996 Amendments.

Nonetheless, a number of commenters

expressed concern about the ability of

large surface water systems that had to

make capital improvements to comply

with all requirements of the Stage 1

DBPR and IESWTR. They pointed out

that capital improvements include more

than just the construction, but also

financing, design, and approval.

EPA believes that the provisions of

Section 1412(b)(10) of the SDWA as

amended allow systems the flexibility

needed to comply. As noted earlier in

this section, States may grant up to an

additional two years compliance time

for an individual system if capital

improvements are necessary. Moreover,

as both of these rules have been under

negotiation since 1992, proposed in

1994 and further clarified in 1997, EPA

believes that most systems have had

substantial time to consider how to

proceed with implementation and to

initiate preliminary planning. Several

commenters also supported delaying the

promulgation of the Stage 1 DBPR for

ground water systems until the GWR is

promulgated, in order to ensure

simultaneous compliance with both

rules. EPA believes that this option

would not be consistent with the regneg agreement, as endorsed by Congress,

because the agreement specifies that the

Stage 1 DBPR will apply to all

community and nontransient

noncommunity water systems.

Moreover, EPA has committed to the

LT1 and GWR promulgation schedule

outlined above precisely to address this

issue.

In conclusion EPA believes that the

compliance deadlines outlined above

for systems covered by this rule are

appropriate and consistent with the

requirements of the 1996 SDWA

amendments. The Agency notes,

however, that some elements of Option

4 outlined in the 1997 NODA apply to

systems that may be covered by future

Long Term Enhanced and Ground Water

rules. EPA intends to follow the

deadline strategy outlined in Option 4

for these future rules. However, as

today’s action only relates to the Stage

1 DBPR, the Agency will defer final

action on deadlines associated with

future rules until those rules,

themselves, are finalized.
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69429

J. Public Notice Requirements

1. Today’s Rule

Today’s action addresses public

notification by promulgating public

notification language for the regulated

compounds in 40 CFR Section 141.32

(e). EPA takes this opportunity to note

that the 1996 amendments to the SDWA

require the Agency to make certain

changes to the public notice regulations.

EPA intends to propose changes to the

public notice requirements in the

Federal Register shortly after

promulgation of the Stage 1 DBPR.

Applicable changes in the public notice

requirements, when they become

effective, will supersede today’s

provisions. In general, the public

notification for the Stage 1 DBPR is not

substantially changed from that

included in the 1994 Proposed Stage 1

DBPR (EPA, 1994a).

2. Background and Analysis

Under Section 1414(c)(1) of the Act,

each owner or operator of a public water

system must give notice to the persons

served by the system of (1) any violation

of any MCL, treatment technique

requirement, or testing provision

prescribed by an NPDWR; (2) failure to

comply with any monitoring

requirement under section 1445(a) of

the Act; (3) existence of a variance or

exemption; (4) failure to comply with

the requirements of a schedule

prescribed pursuant to a variance or

exemption; and (5) notice of the

concentration level of any unregulated

contaminant for which the

Administrator has required public

notice.

EPA promulgated the current

regulations for public notification on

October 28, 1987 (52 FR 41534—EPA,

1987). These regulations specify general

notification requirements, including

frequency, manner, and content of

notices, and require the inclusion of

EPA-specified health effects information

in each public notice. The public

notification requirements divide

violations into two categories (Tier 1

and Tier 2) based on the seriousness of

the violations, with each tier having

different public notification

requirements. Tier 1 violations include

violations of an MCL, treatment

technique, or a variance or exemption

schedule. Tier 1 violations contain

health effects language specified by EPA

which concisely and in non-technical

terms conveys to the public the adverse

health effects that may occur as a result

of the violation. States and water

utilities remain free to add additional

information to each notice, as deemed

appropriate for specific situations. Tier

2 violations include monitoring

violations, failure to comply with an

analytical requirement specified by an

NPDWR, and operating under a variance

or exemption.

Today’s final rule contains specific

health effects language for the

contaminants which are in today’s

rulemaking. EPA believes that the

mandatory health effects language is the

most appropriate way to inform the

affected public of the potential health

implications of violating a particular

EPA standard.

3. Summary of Comments

EPA received comments on the topic

of the public notification language for

TTHM, HAA5, chlorine, chloramines,

chlorine dioxide, and enhanced

coagulation. Some commenters noted

that the language in 141.32(e)(79) is

satisfactory. One commenter requested

that the language for DBPs be modified

to recognize that disinfectants react with

naturally occurring organic and

inorganic matter to form DBPs. Some

commenters did not support the use of

the same public notification language

for both DBP MCL and enhanced

coagulation treatment technique

violations. Several commenters

suggested that the content of the notices

for chlorine, chloramine, and chlorine

dioxide should reflect that disinfection

is an essential step in surface water

treatment. One commenter suggested

that the language for chlorine dioxide

acute effects should be deleted. Other

commenters felt that the notice to

consumers of chlorine dioxide

violations at the treatment facility

which do not result in violations in the

distribution system (nonacute

violations) should not require public

notification.

In response, EPA has modified the

public notification language for DBPs to

indicate that disinfectants react with

naturally occurring organic and

inorganic matter to form DBPs. EPA

believes it is appropriate to use the same

public notification language for the

enhanced coagulation treatment

technique violation as for violations for

the TTHM and HAA5 MCLs, since

enhanced coagulation is meant to limit

exposure to DBPs. EPA believes the

current language in the public

notification language is appropriate to

reflect that disinfection is an essential

step in water treatment. EPA believes

that since the potential health effects

from chlorine dioxide are short-term

that it is appropriate to maintain the

acute effects language to protect the

fetus, infants, and children. In general,

the public notification requirements for

the Stage 1 DBPR will not substantially

change from that included in the 1994

Proposed Stage 1 DBPR (EPA, 1994a).

K. System Reporting and Record

Keeping Requirements

1. Today’s Rule

The Stage 1 DBPR, consistent with the

current system reporting regulations

under 40 CFR 141.31, requires PWSs to

report monitoring data to States within

ten days after the end of the compliance

period. In addition, systems are required

to submit the data required in § 141.134.

These data are required to be submitted

quarterly for any monitoring conducted

quarterly or more frequently, and within

10 days of the end of the monitoring

period for less frequent monitoring.

Systems that are required to do extra

monitoring because of the disinfectant

used have additional reporting

requirements specified. This applies to

systems that use chlorine dioxide (must

report chlorine dioxide and chlorite

results) and ozone (must report bromate

results).

Subpart H systems that use

conventional treatment are required to

report either compliance/

noncompliance with DBP precursor

(TOC) removal requirements or report

which of the enhanced coagulation/

enhanced softening exemptions they are

meeting. There are additional

requirements for systems that cannot

meet the required TOC removals and

must apply for an alternate enhanced

coagulant level. These requirements are

included in § 141.134(b).

Calculation of compliance with the

TOC removal requirements is based on

normalizing the percent removals over

the most recent four quarters, since

compliance is based on that period.

Normalization, which would prescribe

equal weight to the data collected each

month, is necessary since source water

quality changes may change the percent

TOC removal requirements from one

month to another. EPA has developed a

sample reporting and compliance

calculation sheet that will be available

in the enhanced coagulation guidance

manual to assist utilities in making

these calculations.

2. Summary of Comments

There were no significant comments

on the system reporting and

recordkeeping requirements and

therefore EPA is finalizing the

requirements as proposed.

L. State Recordkeeping, Primacy, and

Reporting Requirements

The SDWA provides that States and

eligible Indian Tribes may assume

primary enforcement responsibilities.
69430 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

Fifty-four out of fifty-six State and

territorial jurisdictions have applied for

and received primary enforcement

responsibility (primacy) under the Act.

No Tribes have received primacy. To

obtain primacy for the federal drinking

water regulations, States must adopt

their own regulations which are at least

as stringent as the federal regulations.

This section describes the regulations

and other procedures and policies that

States must adopt to implement the

final Stage 1 DBPR.

To implement the final rule, States are

required to adopt the following

regulatory requirements:

—Section 141.32, Public Notification;

—Section 141.64, MCLs for Disinfection

Byproducts;

—Section 141.65, MRDLs for

Disinfectants;

—Subpart L, Disinfectant Residuals,

Disinfectant Byproducts, and

Disinfection Byproduct Precursors.

In addition to adopting regulations no

less stringent than the federal

regulations, States must adopt certain

requirements related to this regulation

in order to have their program revision

applications approved by EPA. This rule

also requires States to keep specific

records and submit specific reports to

EPA.

On April 28, 1998, EPA amended its

State primacy regulations at 40 CFR

142.12 to incorporate the new process

identified in the 1996 SDWA

amendments for granting primary

enforcement authority to States while

their applications to modify their

primacy programs are under review (63

FR 23362; EPA, 1998i). The new process

grants interim primary enforcement

authority for a new or revised regulation

during the period in which EPA is

making a determination with regard to

primacy for that new or revised

regulation. This interim enforcement

authority begins on the date of the

primacy application submission or the

effective date of the new or revised State

regulation, whichever is later, and ends

when EPA makes a final determination.

However, this interim primacy authority

is only available to a State that has

primacy for every existing national

primary drinking water regulation in

effect when the new regulation is

promulgated.

As a result, States that have primacy

for every existing NPDWR already in

effect may obtain interim primacy for

this rule, beginning on the date that the

State submits its complete and final

primacy application for this rule to EPA,

or the effective date of its revised

regulations, whichever is later. In

addition, a State which wishes to obtain

interim primacy for future NPDWRs

must obtain primacy for this rule.

1. State Recordkeeping Requirements

a. Today’s Rule. The current

regulations in § 142.14 require States

with primacy to keep various records,

including analytical results to determine

compliance with MCLs, MRDLs, and

treatment technique requirements;

system inventories; State approvals;

enforcement actions; and the issuance of

variances and exemptions. The Stage 1

DBPR requires States to keep additional

records of the following, including all

supporting information and an

explanation of the technical basis for

each decision:

(1) Records of determinations made

by the State when the State has allowed

systems additional time to install GAC

or membrane filtration. These records

must include the date by which the

system is required to have completed

installation;

(2) Records of systems that are

required to meet alternative minimum

TOC removal requirements or for whom

the State has determined that the source

water is not amendable to enhanced

coagulation. These records must include

the results of testing to determine

alternative limits and the rationale for

establishing the alternative limits;

(3) Records of subpart H systems

using conventional treatment meeting

any of the enhanced coagulation or

enhanced softening exemption criteria;

(4) Register of qualified operators;

(5) Records of systems with multiple

wells considered to be one treatment

plant for purposes of determining

monitoring frequency;

(6) Records of the sampling plans for

subpart H systems serving more than

3,300 persons must be keep on file at

the State after submission by the system;

(7) A list of laboratories that have

completed performance sample analyses

and achieved the quantitative results for

TOC, TTHMs, HAA5, bromate, and

chlorite; and

(8) A list of all systems required to

monitor for disinfectants and DBPs

under subpart L.

b. Background and Analysis. In

addition to requesting comments on the

requirements (1) through (5), and (7)

and (8) listed above, EPA also requested

comments on whether States should be

required to keep the monitoring plan

submitted by systems serving more than

3,300 people on file at the State after

submission to make it available for

public review.

c. Summary of Comments. There were

several commenters who suggested that

EPA should keep in mind State budget

constraints when requiring specific

additional recordkeeping requirements.

Other commenters stated that they

believed the requirements were

necessary. EPA understands

commenters concerns with requiring

recordkeeping requirements that are

unnecessary, but believes this

information is important to conduct

effective State program oversight,

including the review of State decisions

and their basis. After further review,

EPA has decided to eliminate the

requirement in the proposal that States

must keep records of systems that apply

for alternative TOC performance

criteria. EPA is more concerned with the

systems that are required to meet

alternative TOC performance criteria,

not the systems that have applied for the

alternative performance criteria. In

addition, EPA has added three

recordkeeping requirements, two of

which were originally in the reporting

requirements section and one for which

EPA requested comment.

The first additional requirement will

require States to keep lists of all systems

required to monitor for various

disinfectants and DBPs (#8 above). The

second additional requirement will

require States to maintain a list of

laboratories that have completed

performance sample analyses and

achieved the quantitative results for

TOC, TTHMs, HAA5, bromate, and

chlorite (#6 above). EPA believes both of

these recordkeeping requirements are

necessary to ensure adequate EPA

program oversight. As discussed below,

these two requirements are no longer in

the State reporting requirements as EPA

has decided that the requirements in the

proposal on State reporting

requirements are not needed on a

regular basis, but are needed for

program oversight. The third additional

requirement pertains to the request for

comment in the proposal on

maintaining the monitoring plans

submitted by systems (#6 above).

Several commenters supported this

additional requirement stating that it

was a necessary element for

implementing the final rule. Others

believed it was not necessary to keep

this on file because the public could

request this information from the system

or the State as normal public records.

EPA believes that it is important for

States to review, and keep on file the

systems monitoring plan to ensure that

the PWS is monitoring and calculating

compliance in accordance with the

plan. This will also enable the public to

view the plan. Thus, EPA is adding this

requirement to the final recordkeeping

requirements. In conclusion, based on a

review of all public comments the final
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69431

rule contains eight State recordkeeping

requirements in addition to those

required under current regulations in

§ 142.14.

2. Special Primacy Requirements

a. Today’s Rule. To ensure that a State

program includes all the elements

necessary for an effective and

enforceable program under today’s rule,

a State application for program revision

approval must include a description of

how the State will:

(1) Determine the interim treatment

requirements for systems granted

additional time to install GAC and

membrane filtration under 141.64(b)(2).

(2) Qualify operators of community

and nontransient noncommunity water

systems subject to this regulation under

141.130(c). Qualification requirements

established for operators of systems

subject to 40 CFR Part 141 Subpart H

(Filtration and Disinfection) may be

used in whole or in part to establish

operator qualification requirements for

meeting subpart L requirements if the

State determines that the subpart H

requirements are appropriate and

applicable for meeting subpart L

requirements.

(3) Approve DPD colorimetric tests

kits for free and total chlorine

measurements under 141.131(c)(2).

State approval granted under subpart H

(§ 141.74(a)(2)) for the use of DPD

colorimetric test kits for free chlorine

testing would be considered acceptable

approval for the use of DPD test kits in

measuring free chlorine residuals as

required in subpart L.

(4) Approve parties to conduct

analyses of water quality parameters

under 141.132(a)(2) (pH, alkalinity,

bromide, and residual disinfectant

concentration measurements). The

State’s process for approving parties

performing water quality measurements

for systems subject to subpart H

requirements may be used for approving

parties measuring water quality

parameters for systems subject to

subpart L requirements, if the State

determines the process is appropriate

and applicable.

(5) Define criteria to use in

determining if multiple wells are being

drawn from a single aquifer and

therefore can be considered as a single

source under 141.132(a)(2). Such

criteria will be used in determining the

monitoring frequency for systems using

only ground water not under the direct

influence of surface water.

(6) Approve alternative TOC removal

levels as allowed under 141.135(b).

b. Background and Analysis. As

discussed above, EPA included several

special primacy requirements to ensure

that State programs contain all the

essential elements for an effective

program. Specifically, EPA believes the

special requirements are important to

ensure that the process or approach

used by the State for evaluating whether

the interim treatment in place for

systems granted additional time to

install GAC or membranes or alternative

enhanced coagulation levels will be

protective of public health. The

requirement to have qualified operators

is important because the treatment

technologies used to comply with the

Stage 1 DBPR and the IESWTR

simultaneously are complex and will

require a certain level of expertise. The

requirement to approve parties for

conducting analyses of specific water

quality parameters is important because

each of the parameters required to be

tested is critical to a specific component

of the final rule (e.g., bromide ion is

important because for bromate it is

possible to reduce monitoring from

monthly to once per quarter, if a system

demonstrates that the average raw water

bromide concentration is less than 0.05

mg/L based upon representative

monthly measurements for one year).

Finally, it is important to define the

criteria used to determine if multiple

wells are to be considered a single

source as this could have significant

implications for monitoring.

c. Summary of Comments. There were

no significant comments on the primacy

requirements. The only change from the

proposal was to delete the requirement

that States must have approved parties

to perform temperature evaluations.

This requirement was included in the

proposed rule because of the need to

have accurate measurements as a part of

the process for not allowing

predisinfection credit. Since the final

rule allows credit for compliance with

applicable disinfection requirements

consistent with the SWTR, the

temperature requirement was removed.

3. State Reporting Requirements

a. Today’s Rule. EPA currently

requires in § 142.15 that States report to

EPA information such as violations,

variance and exemption status, and

enforcement actions. The Stage 1 DBPR

does not add any additional reporting

requirements.

b. Background and Analysis. The

preamble to the proposed rule included

six State reporting requirements. These

included:

(1) A list of all systems required to

monitor for various disinfectants and

disinfection byproducts;

(2) A list of all systems for which the

State has granted additional time for

installing GAC or membrane technology

and the basis for the additional time;

(3) A list of laboratories that have

completed performance sample analyses

and achieved the quantitative results for

TOC, TTHMs, HAA5, bromate, and

chlorite;

(4) A list of all systems using multiple

ground water wells which draw from

the same aquifer and are considered a

single source for monitoring purposes;

(5) A list of all Subpart H systems

using conventional treatment which are

not required to operate with enhanced

coagulation, and the reason why

enhanced coagulation is not required for

each system; and

(6) A list of all systems with Stateapproved alternate performance

standards (alternate enhanced

coagulation levels).

c. Summary of Comments. Several

commenters stated that the reporting

requirements were not necessary to

operate an oversight program and that

these reports could be made available

for EPA review during annual audits.

EPA agrees with commenters that the

reports are not necessary to operate an

oversight program, and that if needed

EPA could request this information from

the States. However, EPA does believe

it is important that States maintain this

information in their records. In

conclusion, based on commenters

concerns and for the reasons cited

above, the final rule contains no

additional State reporting requirements

other than those required by 142.15.

M. Variances and Exemptions

1. Today’s Rule

Variances may be granted in

accordance with section 1415(a)(1)(A) of

the SDWA and in accordance with

1415(e) and EPA’s regulations.

Exemptions may be granted in

accordance with section 1416(a) of the

SDWA and EPA’s regulations.

2. Background and Analysis

Variances. The SDWA provides for

two types of variances—general

variances and small system variances.

Under section 1415(a)(1)(A) of the

SDWA, a State which has primary

enforcement responsibility (primacy), or

EPA as the primacy agency, may grant

variances from MCLs to those public

water systems of any size that cannot

comply with the MCLs because of

characteristics of the water sources. The

primacy agency may grant general

variances to a system on condition that

the system install the best available

technology, treatment techniques, or

other means, and provided that

alternative sources of water are not
69432 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

reasonably available to the system. At

the time this type of variance is granted,

the State must prescribe a compliance

schedule and may require the system to

implement additional control measures.

Furthermore, before EPA or the State

may grant a general variance, it must

find that the variance will not result in

an unreasonable risk to health (URTH)

to the public served by the public water

system.

Under section 1413(a)(4), States that

choose to issue general variances must

do so under conditions, and in a

manner, that are no less stringent than

section 1415. Of course, a State may

adopt standards that are more stringent

than the EPA standards. EPA specifies

BATs for general variance purposes.

EPA may identify as BAT different

treatments under section 1415 for

variances other than the BAT under

section 1412 for MCLs. EPA’s section

1415 BAT findings may vary depending

on a number of factors, including the

number of persons served by the public

water system, physical conditions

related to engineering feasibility, and

the costs of compliance with MCLs. In

this final rule, EPA is not specifying

different BAT for variances under

section 1415(a). Section 1415(e)

authorizes the primacy Agency (EPA or

the State) to issue variances to small

public water systems (those serving less

than 10,000 persons) where the system

cannot afford to comply with an MCL

and where the primacy agency

determines that the terms of the

variances ensure adequate protection of

public health (63 FR 1943–57; EPA,

1998j). These variances also may only

be granted where EPA has identified a

variance technology under Section

1412(b)(15) for the contaminant, system

size and source water quality in

question.

Prior to the 1996 SDWA amendments,

EPA was required to set the MCL for a

contaminant as close to the MCLG as is

feasible. Section 1412(b)(4)(D) of the

SDWA states that ‘‘the term ‘‘feasible’’

means with the use of the best

technology, treatment techniques and

other means which the Administrator

finds, after examination for efficacy

under field conditions and not solely

under laboratory conditions, are

available (taking cost into

consideration).’’

The cost assessment for the feasibility

determinations have historically been

based upon impacts to regional and

large metropolitan water systems

serving populations greater than 50,000

people. Since large systems served as

the basis for the feasibility

determinations, the technical and/or

cost considerations associated with

these technologies often were not

applicable to small water systems.

While EPA will continue to use

feasibility for large systems in setting

NPDWRs, the 1996 amendments to the

SDWA specifically require EPA to make

small system technology assessments for

both existing and future regulations.

The 1996 amendments to the SDWA

identifies three categories of small

public water systems that need to be

addressed: (1) those serving a

population between 3301 to 10,000; (2)

those serving a population of 501—

3300; and (3) those serving a population

of 26—500. The SDWA requires EPA to

make determinations of available

compliance technologies and, if needed,

variance technologies for each size

category. A compliance technology is a

technology that is affordable and that

achieves compliance with the MCL and/

or treatment technique. Compliance

technologies can include point-of-entry

or point-of-use treatment units. Variance

technologies are only specified for those

system size/source water quality

combinations for which there are no

listed compliance technologies.

EPA has completed an analysis of the

affordability of DBP control

technologies for each of the three size

categories included above. Based on this

analysis, multiple affordable

compliance technologies were found for

each of the three system sizes (EPA,

1998q and EPA, 1998r) and therefore

variance technologies were not

identified for any of the three size

categories. The analysis was consistent

with the methodology used in the

document ‘‘National-Level Affordability

Criteria Under the 1996 Amendments to

the Safe Drinking Water Act’’ (EPA,

1998s) and the ‘‘Variance Technology

Findings for Contaminants Regulated

Before 1996’’ (EPA, 1998t).

Exemptions. Under section 1416(a),

EPA or a State may exempt a public

water system from any requirements

related to an MCL or treatment

technique of an NPDWR, if it finds that

(1) due to compelling factors (which

may include economic factors such as

qualification of the PWS as serving a

disadvantaged community), the PWS is

unable to comply with the requirement

or implement measure to develop an

alternative source of water supply; (2)

the exemption will not result in an

unreasonable risk to health; and; (3) the

PWS was in operation on the effective

date of the NPWDR, or for a system that

was not in operation by that date, only

if no reasonable alternative source of

drinking water is available to the new

system; and (4) management or

restructuring changes (or both) cannot

reasonably result in compliance with

the Act or improve the quality of

drinking water.

If EPA or the State grants an

exemption to a public water system, it

must at the same time prescribe a

schedule for compliance (including

increments of progress or measures to

develop an alternative source of water

supply) and implementation of

appropriate control measures that the

State requires the system to meet while

the exemption is in effect. Under section

1416(b)(2)(A), the schedule prescribed

shall require compliance as

expeditiously as practicable (to be

determined by the State), but no later

than 3 years after the effective date for

the regulations established pursuant to

section 1412(b)(10). For public water

systems which do not serve more than

a population of 3,300 and which need

financial assistance for the necessary

improvements, EPA or the State may

renew an exemption for one or more

additional two-year periods, but not to

exceed a total of 6 years, if the system

establishes that it is taking all

practicable steps to meet the

requirements above.

A public water system shall not be

granted an exemption unless it can

establish that either: (1) the system

cannot meet the standard without

capital improvements that cannot be

completed prior to the date established

pursuant to section 1412(b)(10); (2) in

the case of a system that needs financial

assistance for the necessary

implementation, the system has entered

into an agreement to obtain financial

assistance pursuant to section 1452 or

any other Federal or state program; or

(3) the system has entered into an

enforceable agreement to become part of

a regional public water system.

3. Summary of Comments on Variance

and Exemptions

In the 1994 proposal, EPA requested

comment on whether exemptions to the

rule should be granted if a system could

demonstrate to the State that due to

unique water quality characteristics it

could not avoid, through the use of

BAT, the possibility of increasing total

health risk to its consumers by

complying with the Stage 1 regulations.

The Agency requested information

under which such a scenario may

unfold. Several commenters supported

granting exemptions provided a system

could demonstrate that installation of

BAT will increase the total health risk.

After additional consideration, EPA

believes it is not appropriate, for several

reasons, to grant exemptions based on a

demonstration that the use of BAT

could increase the total health risk by

complying with the Stage 1 DBPR. First,
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69433

EPA does not believe the analytical

tools and methodologies are currently

available that would allow a

determination of whether the total

health risk from the installation of BAT

would increase. Second, at the time of

proposal there was concern that in

waters with high bromide

concentrations it may be possible to

increase the concentrations of certain

brominated DBPs when using precursor

removal processes even though the

concentrations of the TTHMs and HAA5

may decrease. Also, at the time of

proposal, the health risks associated

with many of the brominated DBPs was

unknown, and it was unclear whether

the benefits of lowering the

concentrations of chlorinated DBPs

outweigh the possible downside risks of

increasing certain brominated DBPs.

Since the proposal, some additional

health effects research has been

completed evaluating the toxicity of

brominated DBPs. However, this

research is still preliminary and no

conclusions can be drawn on the

potential for increased risks from the

brominated DBPs. In addition, it is

unclear to what extent the use of

precursor removal processes will change

the concentrations of certain brominated

DBPs. The ICR data should provide

some additional information that may

be helpful in this area along with

additional ongoing research. This

information will be available for

consideration in the Stage 2 rule

deliberations. Based on the reasons

stated above, EPA does not believe it is

appropriate to allow exemptions to the

rule based on a finding that the

installation of BAT would increase the

total risk from DBPs.

N. Laboratory Certification and

Approval

1. Today’s Rule

EPA recognizes that the effectiveness

of today’s regulations depends on the

ability of laboratories to reliably analyze

the regulated disinfectants and DBPs at

the MRDL or MCL, respectively.

Laboratories must also be able to

measure the trihalomethanes and

haloacetic acids at the reduced

monitoring trigger levels, which are

between 25 and 50 percent of the MCLs

for these compound classes. EPA has

established State primacy requirements

for a drinking water laboratory

certification program for the analysis of

DBPs. States must adopt a laboratory

certification program as part of primacy.

[40 CFR 142.10(b)]. EPA has also

specified laboratory requirements for

analyses of DBP precursors and

disinfectant residuals which must be

conducted by approved parties. [40 CFR

141.89 and 141.74]. EPA’s ‘‘Manual for

the Certification of Laboratories

Analyzing Drinking Water’’, EPA 815–

B–97–001—(EPA, 1997g), specifies the

criteria for implementation of the

drinking water laboratory certification

program.

In today’s rule, EPA is promulgating

MCLs for TTHMs, HAA5, bromate, and

chlorite. Today’s rule requires that only

certified laboratories be allowed to

analyze samples for compliance with

the proposed MCLs. For the

disinfectants and certain other

parameters in today’s rule, which have

MRDLs or monitoring requirements,

EPA is requiring that analyses be

conducted by a party acceptable to the

State.

Performance evaluation (PE) samples,

which are an important tool in the

SDWA laboratory certification program

(laboratories seeking certification) may

be obtained from a PE provider

approved by the National Institute of

Science and Technology (NIST). To

receive and maintain certification, a

laboratory must use a promulgated

method and, at least once per year,

successfully analyze an appropriate PE

sample. In the drinking water PE

studies, NIST-approved providers will

provide samples for bromate, chlorite,

five haloacetic acids, four

trihalomethanes, free chlorine, and

alkalinity. The NIST-approved PE

providers will provide total chlorine

and TOC samples in the wastewater PE

studies and have the potential to

provide these samples for drinking

water studies. Due to the lability of

chlorine dioxide, EPA does not expect

a suitable PE sample can be designed for

chlorine dioxide measurements.

PE Sample Acceptance Limits for

Laboratory Certification. Historically,

EPA has set minimum PE acceptance

limits based on one of two criteria:

statistically derived estimates or fixed

acceptance limits. Statistical estimates

are based on laboratory performance in

the PE study. Fixed acceptance limits

are ranges around the true concentration

of the analyte in the PE sample. Today’s

rule combines the advantages of these

approaches by specifying statisticallyderived acceptance limits around the

study mean, within specified minimum

and maximum fixed criteria.

EPA believes that specifying

statistically-derived PE acceptance

limits with upper and lower bounds on

acceptable performance provides the

flexibility necessary to reflect

improvement in laboratory performance

and analytical technologies. The

acceptance criteria maintain minimum

data quality standards (the upper

bound) without artificially imposing

unnecessarily strict criteria (the lower

bound). Therefore, EPA is establishing

the following acceptance limits for

measurement of bromate, chlorite, each

haloacetic acid, and each

trihalomethane in a PE sample.

EPA is defining acceptable

performance for each chemical

measured in a PE sample from estimates

derived at a 95% confidence interval

from the data generated by a statistically

significant number of laboratories

participating in the PE study. However,

EPA requires that these acceptance

criteria not exceed ±50% nor be less

than ±15% of the study mean. If

insufficient PE study data are available

to derive the estimates required for any

of these compounds, the acceptance

limit for that compound will be set at

±50% of the study true value. The true

value is the concentration of the

chemical that EPA has determined was

in the PE sample.

EPA recognizes that when using

multianalyte methods, the data

generated by laboratories that are

performing well will occasionally

exceed the acceptance limits. Therefore,

to be certified to perform compliance

monitoring using a multianalyte

method, laboratories are required to

generate acceptable data for at least 80%

of the regulated chemicals in the PE

sample that are analyzed with the

method. If fewer than five compounds

are included in the PE sample, data for

each of the analytes in that sample must

meet the minimum acceptance criteria

in order for the laboratory to be

certified.

Approval Criteria for Disinfectants

and Other Parameters. Today’s rule

establishes MRDLs for the three

disinfectants—chlorine, chloramines,

and chlorine dioxide. In addition, EPA

has established monitoring

requirements for TOC, alkalinity, and

bromide; there are no MCLs for these

parameters. In previous rules [40 CFR

141.28, .74, and .89], EPA has required

that measurements of alkalinity,

disinfectant residuals, pH, temperature,

and turbidity be made with an approved

method and conducted by a party

approved (not certified) by the State. In

today’s rule, EPA requires that samples

collected for compliance with today’s

requirements for alkalinity, bromide,

residual disinfectant, and TOC be

conducted with approved methods and

by a party approved by the State.

Other Laboratory Performance

Criteria. For all contaminants and

parameters required to be monitored in

today’s rule, the States may impose

other requirements for a laboratory to be
69434 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

certified or a party to be approved to

conduct compliance analyses.

2. Background and Analysis

The laboratory certification and

approval requirements that today’s rule

establishes are unchanged from those

proposed by EPA in 1994.

3. Summary of Comments

EPA received few comments on

laboratory certification and approval.

Commenters requested clarification of

the use of the ±50% upper bound and

±15% lower bound, along with the use

of statistically derived limits. EPA

believes that statistically derived limits

provide flexibility to allow laboratory

certification standards to reflect

improvement in laboratory performance

and analytical technologies. As

laboratories become more proficient in

conducting these analyses, statistically

derived acceptance limits may drop.

However, to prevent the exclusion of

laboratories capable of producing data

of sufficient quality for compliance

purposes, EPA has established a lower

bound for acceptance limits of ±15%.

EPA is imposing an upper bound on

acceptable performance to establish

minimum data quality standards.

Results outside of this range have

unacceptable accuracy for compliance

determinations. These upper and lower

bounds were not determined

statistically; they are the data quality

objectives the Agency has determined as

acceptable.

IV. Economic Analysis

Under Executive Order 12866,

Regulatory Planning and Review, EPA

must estimate the costs and benefits of

the Stage 1 DBPR in a Regulatory Impact

Analysis (RIA) and submit the analysis

to Office of Management and Budget

(OMB) in conjunction with publishing

the final rule. EPA has prepared an RIA

to comply with the requirements of this

Order. This section provides a summary

of the information from the RIA for the

Stage 1 DBPR (USEPA 1998g).

A. Today’s Rule

EPA has estimated that the total

annualized cost, for implementing the

Stage 1 DBPR is $701 million in 1998

dollars (assuming a 7 percent cost of

capital). This estimate includes

annualized treatment costs to utilities

($593 million), start-up and annualized

monitoring costs to utilities ($91.7

million), and startup and annualized

monitoring costs to states ($17.3

million). Annualized treatment costs to

utilities includes annual operation and

maintenance costs ($362 million) and

annualized capital costs assuming 7

percent cost of capital ($230 million).

The basis for these estimates, and

alternate cost estimates using different

cost of capital assumptions are

described later in this section. While the

benefits of this rule are difficult to

quantify because of the uncertainty

associated with risks from exposure to

DBPs (and the resultant reductions in

risk due to the decreased exposure from

DBPs), EPA believes that there is a

reasonable likelihood that the benefits

will exceed the costs. Various

approaches for assessing the benefits are

considered and described in the benefits

and net benefits sections of this

preamble.

B. Background

1. Overview of RIA for the Proposed

Rule

In the RIA for the 1994 proposed

Stage 1 DBPR (EPA, 1994i) EPA

estimated the national capital and

annualized utility costs (sum of

amortized capital and annual operating

costs, assuming 10% cost of capital) for

all systems at $4.4 billion and $1.04

billion, respectively. The cost and

reduction in DBP exposure estimates of

the 1994 RIA were derived using a

Disinfection Byproduct Regulatory

Analysis Model (DBPRAM). The

DBPRAM consisted of a collection of

analytical models which used Monte

Carlo simulation techniques to produce

national forecasts of compliance and

exposure reductions for different

regulatory scenarios. The TWG,

representing members of the Reg. Neg.

Committee, used the best available

information at the time as inputs to the

DBPRAM, and for making further

adjustments to the model predictions.

The Stage 1 DBPR compliance and

exposure forecasts were affected by

constraints imposed by the 1994

proposed IESWTR option which would

have required systems to provide

enough disinfection, while not allowing

for disinfection credit prior to TOC

removal by enhanced coagulation, to

achieve a 10¥4 annual risk of infection

from Giardia (EPA, 1994a). The

compliance forecast assumed that a

substantial number of systems would

need to install advanced technologies to

meet the Stage 1 DBPR because of

needing to achieve the 10¥4 annual risk

level from Giardia while no longer being

allowed disinfection credit prior to TOC

removal.

Predicted benefits for the proposed

Stage 1 DBPR were derived assuming a

baseline risk ranging from 1 to 10,000

cancer cases per year (based on analysis

of available toxicological and

epidemiological data) and assuming

reductions in the cancer risks were

proportional to reductions in TTHM,

HAA5, or TOC levels (predicted from

compliance forecasts). Negotiators

agreed that the range of possible risks

attributed to chlorinated water should

consider both toxicological data and

epidemiological data, including the

Morris et al. (1992) estimates. No

consensus, however, could be reached

on a single likely risk estimate.

Therefore, the predicted benefits for the

proposal ranged from one to several

thousands cases of cancer being avoided

per year after implementation of the

Stage 1 DBPR. Despite, the uncertainty

in quantifying the benefits from the

Stage 1 DBPR, the Reg. Neg. Committee

recognized that risks from chlorinated

water could be large, and therefore

should be reduced. The Reg. Neg.

Committee also recommended that the

proposed Stage 1 DBPR provided the

best means for reducing risks from DBPs

until better information become

available.

For a more detailed discussion of the

cost and benefit analysis of the 1994

proposed DBPR refer to the preamble of

the proposed rule (EPA, 1994a) and the

RIA for the proposed rule (EPA, 1994i).

2. Factors Affecting Changes to the 1994

RIA

a. Changes in Rule Criteria. Based on

the new data reflecting the feasibility of

enhanced coagulation, as discussed

previously, the enhanced coagulation

requirements were modified by

decreasing the percent TOC removal

requirements by 5 percent for systems

with low TOC level waters (i.e., 2–4 mg/

L TOC). These new percent TOC

removal requirements were used with

new source and finished water TOC

occurrence data to revise the estimates

for the number of systems requiring

enhanced coagulation.

The IESWTR was revised from the

proposal to allow inactivation credit for

disinfection prior to and during stages

of treatment for precursor removal.

Also, the proposed IESWTR was revised

to include disinfection benchmark

criteria, in lieu of requiring treatment to

an acceptable risk level, to prevent

increases in microbial risk while

systems complied with the Stage 1

DBPR. These two rule changes were

considered in revising the forecasts of

compliance and changes in exposure

resulting from the Stage 1 DBPR.

b. New Information Affecting DBP

Occurrence and Compliance Forecasts.

Since the rule was proposed, new

sources of data have become available

that were used to update the 1994 RIA.

The new data includes:
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69435

• Updated costs for different

treatment technologies (e.g.,

membranes) used in the DBP Cost and

Technology Document, (EPA, 1998k);

• 1996 data from the AWWA Water

Industry Data Base on TOC, TTHM and

HAA5 occurrence, and disinfection

practices;

• Plant schematics of treatment

processes for ICR utilities;

• Research data from numerous

sources regarding the efficacy of

enhanced coagulation for precursor

removal and resultant DBP formation

(Krasner, 1997; and EPA, 1997b);

• New research results produced in

jar tests by TWG members documenting

the effect of moving the point of

predisinfection under varying

conditions (Krasner, 1997 and EPA,

1997b).

This new information has been

described in the 1997 DBP NODA (EPA,

1997b). Public comments received in

1997, supported using the above

information in revising the decision tree

analysis. Discussion on the decision tree

changes are in section IV.C of this

preamble.

c. New Epidemiology Information.

Since the proposal, EPA has completed

an reassessment of the Morris et al.

(1992) meta-analysis (Poole, 1997).

Review of the meta-analysis indicated

that the estimate of cancer cases had

limited utility for risk assessment

purposes for methodological reasons

(EPA, 1998l and EPA, 1998m). EPA has

decided not to use the Morris et al.

(1992) meta-analysis to estimate the

potential benefits from the Stage 1

DBPR. EPA has considered new

epidemiology studies conducted since

the time of proposal and completed an

assessment of the potential number of

bladder cancer cases that could be

attributed to exposure from chlorinated

surface waters. Based on this assessment

of epidemiological studies, EPA

estimates that between 1100–9300

bladder cancer cases per year could be

attributed to exposure to chlorinated

surface waters (EPA, 1998c). Due to the

wide uncertainty in these estimates, the

true number of attributable cases could

also be zero. The basis for these bladder

cancer case estimates and potential

reductions in risk resulting from the

Stage 1 DBPR is discussed further in the

benefits and net benefits sections that

follow.

C. Cost Analysis

National cost estimates of compliance

with the Stage 1 DBPR were derived

from estimates of utility treatment costs,

monitoring and reporting costs, and

start-up costs. Utility treatment costs

were derived using compliance forecasts

of technologies to be used and unit costs

for the different technologies.

1. Revised Compliance Forecast

The TWG, supporting the M–DBP

Advisory Committee, used the 1996

AWWA Water Industry Data Base

(WIDB) to reevaluate the compliance

decision tree used in the RIA for the

1994 proposal. The WIDB provided

occurrence data on TOC level in raw

water and finished water, TTHM and

HAA5 levels within distribution

systems, and information on

predisinfection practices.

The above information was used to

predict treatment compliance choices

that plants would likely make under the

Stage 1 DBPR. Table IV–1 illustrates

how the compliance forecast changed

for large systems using surface water

since the time of proposal.

TABLE IV–1.—COMPARISONS OF COMPLIANCE FORECASTS FOR SURFACE WATER SYSTEMS SERVING ≥10,000

POPULATION FROM THE 1994 PROPOSAL AND FINAL RULE

Treatment

1994 1998

# systems % systems # systems % systems

(A) No Further Treatment ............................................................................................. 386 27.7 544 39.0

(B) Chlorine/Chloramines ............................................................................................. 41 2.9 231 16.6

(C) Enhanced Coagulation + Chloramines .................................................................. 136 9.7 265 19.0

(D) Enhanced Coagulation + Chlorine ......................................................................... 600 43.0 265 19.0

(E) Ozone, Chlorine Dioxide, Granular Activated Carbon, Membranes ...................... 232 16.6 90 6.5

Total* ..................................................................................................................... 1,395 100 1,395 100

* May not add to total due to independent rounding.

Notable is that the percentage of systems

predicted to use advanced technologies

(ozone, chlorine dioxide, GAC, or

membrane) dropped from 17 percent to

6.5 percent since proposal, and the

percentage of systems not affected by

the rule increased from 28 percent to 39

percent. This shift in predicted

compliance choices is mainly attributed

to less stringent disinfection

requirements under the IESWTR which

would reduce the formation of DBPs

and reduce the number of systems

requiring treatment to meet the Stage 1

DBPR. It also appears that a substantial

number of systems may have already

made treatment changes to comply with

the 1994 proposed rule.

Table IV–2 illustrates how the

compliance forecast changed for small

systems using surface water since the

time of proposal. As for large systems,

the percentage of systems predicted to

use advanced technologies dropped

substantially, from 17 percent to 6.5

percent. This drop in use of advanced

technology (i.e., ozone/chloramines and

membrane technologies) is attributed to

the change in the IESWTR (as described

above) from the time of proposal.

However, unlike for large systems, the

overall percentage of systems predicted

to require treatment modifications did

not change. A higher percentage of

small systems (70 percent) are predicted

to be affected than large systems (61

percent) because previously smaller

systems did not have to comply with a

TTHM standard.
69436 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

TABLE IV–2.—COMPARISON OF COMPLIANCE DECISION TREE FOR SURFACE WATER SYSTEMS SERVING <10,000

POPULATION FROM THE 1994 PROPOSAL AND FINAL RULE

1994 1998

# systems % systems # systems % systems

No Further Treatment ................................................................................................... 1,549 30 1,549 30

Number of Affected Systems ....................................................................................... 3,615 70 3,615 70

Treatment:

Chlorine/Chloramine .............................................................................................. 155 3.0 826 16.0

Enhanced Coagulation .......................................................................................... 2,169 42.0 1,983 38.4

Enhanced Coagulation/Chloramine ....................................................................... 465 9.0 465 9.0

Ozone/Chloramine ................................................................................................. 258 5.0 184 3.6

Enhanced Coagulation+Ozone, Chloramine ......................................................... 258 5.0 0 0

Membranes ............................................................................................................ 310 6.0 157 3.0

Table IV–3 illustrates the compliance

forecast for ground water systems. This

forecast did not change from the time of

proposal. A smaller percentage of small

ground water systems are anticipated to

need treatment changes (12 percent)

than large ground water systems (15

percent) because the use of disinfectants

is more prevalent in large versus small

ground water systems.

TABLE IV–3.—COMPLIANCE DECISION TREE FOR ALL GROUND WATER SYSTEMS

Systems <10,000 Systems ≥10,000

# systems % systems # systems % systems

No Further Treatment ....................................................................................................... 59,847 88 1,122 85

Percentage of Affected Systems ...................................................................................... 8,324 12 198 15

Treatment:

Chlorine/Chloramine .................................................................................................. 5,403 8 119 9

Ozone/Chloramine ..................................................................................................... 0 0 26 2

Membranes ................................................................................................................ 2,921 4 53 4

2. System Level Unit Costs

Tables IV–4 and IV–5 present the unit cost estimates in 1998 dollars that were utilized for each of the different treatment technologies in each system size category. Unit costs are presented in $ per 1000 gallons which includes

operation and maintenance costs and amortized capital costs (using a 7% discount rate and a 20 year amortization

period). One dollar per thousand gallons equates to approximately $100 per household per year as an average for

communities in the U.S. More detailed information on these unit costs is available from the EPA’s Cost and Technology

Document (EPA, 1998k).

TABLE IV–4.—SURFACE WATER SYSTEMS COSTS FOR DBP CONTROL TECHNOLOGIES ($/KGAL) AT 7% COST OF CAPITAL

Population size category

25–100 100–500 500–1K 1–3.3K 3.3–10K 10–25K 25–50K 50–75K 75–100K 100K–

500K 500K–1M >1M

Chlorine/Chloramine .............. 0.71 0.19 0.06 0.03 0.03 0.02 0.01 0.01 0.01 0.01 0.01 0.01

Enhanced Coagulation (EC) 0.15 0.13 0.12 0.11 0.09 0.08 0.07 0.07 0.07 0,07 0.06 0.06

EC/Chloramine ...................... 0.87 0.32 0.18 0.14 0.12 0.09 0.08 0.08 0.08 0.07 0.07 0.07

Ozone/Chloramine ................. 12.67 3.21 1.05 0.52 0.38 0.23 0.13 0.10 0.08 0.06 0.04 0.04

EC+Ozone, Chloramine ........ 12.82 3.34 1.17 0.63 0.47 0.30 0.20 0.17 0.15 0.13 0.11 0.10

EC+GAC10 ............................ 6.24 2.43 1.21 0.81 0.59 0.46 0.37 0.35 0.29 0.24 0.19 0.16

EC+GAC20 ............................ 14.11 5.87 3.45 2.45 1.87 1.48 1.05 1.00 0.90 0.64 0.48 0.41

Chlorine Dioxide .................... 24.33 5.73 1.65 0.64 0.24 0.11 0.07 0.07 0.06 0.05 0.04 0.04

Membranes ............................ 3.40 3.47 3.39 2.65 1.72 0.96 0.96 0.87 0.87 0.87 0.87 0.87

TABLE IV–5.—GROUND WATER SYSTEMS COSTS FOR DBP CONTROL TECHNOLOGIES ($/KGAL) AT 7% COST OF CAPITAL

Population size category

25–100 100–500 500–1K 1–3.3K 3.3–10K 10–25K 25–50K 50–75K 75–100K 100K–

500K 500K–1M >1M

Chlorine/Chloramine .............. 0.72 0.19 0.06 0.03 0.03 0.02 0.01 0.01 0.01 0.01 0.01 0.01

Ozone/Chloramine ................. 12.67 3.21 1.05 0.52 0.38 0.23 0.13 0.10 0.08 0.06 0.04 0.04

Membranes ............................ 3.41 3.47 3.39 2.65 1.72 0.96 0.96 0.87 0.87 0.87 0.87 0.87

3. National Costs

Table IV–6 provides a detailed summary of national costs in 1998 dollars under the Stage 1 DBPR for different cost of capital assumptions under a 20 year amortization period. A cost of capital rate of 7 percent was used to

calculate the unit costs for the national compliance cost model. This rate represents the standard discount rate preferred

by OMB for benefit-cost analyses of government programs and regulations. The 3 percent and 10 percent rates are

provided as a sensitivity analysis to show different assumptions about the cost of capital that would affect estimated
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69437

costs. The 10 percent rate also provides a link to the 1994 Stage 1 DBPR cost analysis which was based on a 10

percent rate. EPA believes that the cost estimates presented in Table IV–6 are probably within +/¥30 percent. Uncertainty

around the cost estimates pertain to compliance forecast estimates, unit cost estimates for the different technologies

as they may pertain to individual sites, and estimated costs associated with monitoring.

TABLE IV–6.—SUMMARY OF COSTS UNDER THE STAGE 1 DBPR ($000)

Utilities Costs

Surface water systems Ground water systems

All systems

Small Large Total Small Large Total

Summary of Costs at 3 Percent Cost of Capital

Treatment Costs

Total Capital Costs .................................... 242,652 554,564 797,216 997,537 528,539 1,526,076 2,323,292

Annual O&M .............................................. 23,068 201,308 224,376 83,910 54,243 137,153 362,530

Annualized Capital Costs .......................... 16,326 37,161 53,487 67,287 35,618 102,905 156,392

Annual Utility Treatment Costs ................. 39,394 238,469 277,863 151,197 89,861 240,058 518,922

Monitoring and Reporting Cost:

Start-Up Costs ................................... 59 28 87 674 26 700 787

Annual Monitoring .............................. 10,867 14,619 25,486 38,803 26,326 65,129 90,615

State Costs:

Start-Up Costs ................................... .................... .................... .................... .................... .................... .................... 2,919

Annual Monitoring .............................. .................... .................... .................... .................... .................... .................... 13,243

Total Annual Costs at 3 Percent

Cost of Capital ........................ .................... .................... .................... .................... .................... .................... 626,486

Summary of Costs at 7 Percent Cost of Capital

Total Capital Costs .................................... 242,652 554,564 797,216 997,537 528,539 1,526,076 2,323,292

Annual O&M .............................................. 23,068 201,308 224,376 83,910 54,243 137,153 362,530

Annualized Capital Costs .......................... 22,786 62,355 85,141 94,403 50,046 144,499 229,590

Annual Utility Treatment Costs ................. 45,855 263,663 309,518 178,313 104,289 282,602 592,120

Monitoring and Reporting Cost:

Start-Up Costs ................................... 82 39 121 946 36 982 1,103

Annual Monitoring .............................. 10,867 14,619 25,486 38,803 26,326 65,129 90,615

State Costs:

Start-Up Costs ................................... .................... .................... .................... .................... .................... .................... 4,099

Annual Monitoring .............................. .................... .................... .................... .................... .................... .................... 13,243

Total Annual Costs at 7 Percent

Cost of Capital ........................ .................... .................... .................... .................... .................... .................... 701,180

Summary of Costs at 10 Percent Cost of Capital

Total Capital costs .................................... 242,652 554,564 797,216 997,537 528,539 1,526,076 2,323,292

Annual O&M .............................................. 23,068 201,308 224,376 83,910 54,243 137,153 362,530

Annualized Capital Costs .......................... 28,423 74,639 103,062 117,328 62,522 179,850 282,912

Annual Utility Treatment Costs ................. 51,491 275,947 327,438 201,238 116,765 317,003 645,442

Monitoring and Reporting Cost:

Start-Up Costs ................................... 102 48 150 1,177 45 1,222 1,372

Annual Monitoring .............................. 10,867 14,619 25,486 38,803 26,326 65,129 90,615

State Costs:

Start-Up Costs ................................... .................... .................... .................... .................... .................... .................... 5,100

Annual Monitoring .............................. .................... .................... .................... .................... .................... .................... 13,243

Total Annual Costs at 10 Percent

Cost of Capital ........................ .................... .................... .................... .................... .................... .................... 755,772

The total national costs of the final

Stage 1 DBPR are less than estimated in

the RIA for the proposed rule in 1994.

The estimated capital costs of the 1994

proposal in 1998 dollars is $4.97 billion

and the total annual cost (assuming a 10

percent cost of capital as was assumed

in 1994) is $1.3 billion. The drop in

national costs from the 1994 proposal is

mainly attributed to the lowering of the

number of surface water systems

anticipated to need advanced

technologies and lower membrane

technology costs as described above.

D. Benefits Analysis

1. Exposure Assessment

A large portion of the U.S. population

is exposed to DBPs via drinking water.

Over 200 million people in the U.S. are

served by PWSs which apply a

disinfectant (e.g., chlorine) to water in

order to provide protection against

microbial contaminants. Because of the

large number of people potentially

exposed to DBPs, there is a substantial

concern for any health risks which may

be associated with exposure to DBPs.

Several factors are necessary to assess

the exposure to DBPs: the size of the

population potentially at risk; the

method and rate of ingestion; and the

concentration of DBPs in drinking
69438 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

water. Because DBPs are formed in

drinking water by the reaction of

disinfectants with natural organic and

inorganic matter, the population at risk

is identified as the population served by

drinking water systems that disinfect.

The population served by each of four

system categories, taken from recent

Safe Drinking Water Act Information

System data (SDWIS) is estimated in

Table IV–7. Based on recent information

from SDWIS, it was assumed that all

surface water systems disinfect and a

portion of ground water systems

disinfect (95 percent by population

among large systems and 83 percent by

population among small systems).

Approximately 239 million persons are

estimated to be served by water systems

that disinfect and are potentially

exposed to DBPs. This widespread

exposure represents over 88 percent of

the total U.S. population (270 million).

The route of exposure is through

drinking disinfected tap water.

TABLE IV–7.—POPULATION POTENTIALLY EXPOSED TO DBPS

Population

served

% of population receiving disinfected

water

Population

served by systems that disinfect

Large Surface Water: >10,000 persons ....................................................................................... 141,297,000 100 141,297,000

Small Surface Water: <10,000 persons ....................................................................................... 17,232,000 100 17,232,000

Large Ground Water: >10,000 persons ....................................................................................... 56,074,000 95 53,270,300

Small Ground Water: < 10,000 persons ...................................................................................... 32,937,000 83 27,337,710

Total ...................................................................................................................................... ........................ ........................ 239,137,010

In general, little data are available on

the occurrence of DBPs on a national

basis. Although there is sufficient

occurrence data available for THMs in

large water systems to develop a

national occurrence distribution for that

subset of systems, data are limited for

small water systems. Similarly, some

occurrence data for HAA5 are available

for large surface water systems, but not

small surface water and groundwater

systems.

2. Baseline Risk Assessment Based on

TTHM Toxicological Data

EPA performed a quantitative risk

assessment using the dose-response

information on THMs. This assessment,

however, captures only a portion of the

potential risk associated with DBPs in

drinking water. It is not possible, given

existing toxicological and exposure

data, to gauge how much of the total

cancer risk associated with the

consumption of chlorinated drinking

water is posed by TTHMs alone. An

assessment of THMs, however, provides

some estimation of the potential human

risk, albeit limited.

Performing the risk assessment based

on TTHM toxicological data requires

making several assumptions and

extrapolations (from a nonhuman

species to humans, from high doses in

the laboratory study to lower

environmental exposures, and from a

nondrinking water route to the relevant

route of human exposure). Assumptions

are also made about the occurrence of

TTHMs and the individual DBPs. EPA

estimated the pre-Stage 1 DBPR TTHM

concentration levels by calculating a

weighted average (based on populations

receiving disinfected waters) of TTHM

levels among the different system type

categories described in Table IV–7.

TTHM levels among systems serving

greater than 10,000 people were

estimated based on average

concentrations among systems in

AWWA’s WIDB. TTHM levels in

systems serving less than 10,000 people

were estimated through modeling.

Modeling consisted of applying TTHM

predictive equations to estimates of DBP

precursor levels and treatment

conditions. The mean weighted average

baseline TTHM concentrations among

all the system type categories was 44 μg/

L.

Occurrence data from an EPA DBP

field study indicate that chloroform is

the most common THM (in general,

about 70 percent of total THMs), with

bromoform being the least common (1

percent). Bromodichloromethane has an

occurrence of approximately 20 percent

of the total THMs, with

dibromochloromethane comprising the

final 8 percent of the total THMs. In the

absence of more detailed occurrence

data, these proportions are used to

divide the average TTHM concentration

into the concentration for the four

individual compounds.

Two estimates of risk factors were

used to estimate the cancer incidence.

The first set of lifetime unit risk factors

represent the upper 95 percent

confidence limit of the dose-response

function. The second estimate of

lifetime unit risk is the maximum

likelihood estimate used in the 1994

analysis that represents the central

tendency of the dose-response function

(Bull, 1991). The annual unit risk is

calculated by dividing the lifetime risk

by a standard assumption of 70 years

per lifetime. To calculate the annual

incidence of cancer due to consumption

of TTHMs in drinking water, the annual

drinking water unit risk is multiplied by

the number of units, in this case the

concentration of TTHMs in μg/L, broken

out into individual THMs based on the

proportions presented above. Based on

these cancer risk estimates derived from

laboratory animal studies, the annual

95th percentile upper bound number of

cancer cases attributable to TTHMs is

approximately 100. This means that

there is a 95 percent chance that the

annual number of cases are less than or

equal to 100. Using the maximum

likelihood or ‘‘best’’ estimates, the

annual number of cancer cases is about

2.

3. Baseline Analysis Based on

Epidemiology Data

Epidemiological studies can be used

to assess the overall population risk

associated with a particular exposure.

Since the late 1970s, epidemiological

investigations have attempted to assess

whether chlorinated drinking water

contributes to the incidence of bladder,

colon, rectal, and other cancers. Several

studies have reported a weak

association between bladder cancer and

exposure to chlorinated drinking water,

but a causal relationship has not been

confirmed (Freedman, et al., 1997).

Several cancer epidemiological

studies examining the association

between exposure to chlorinated surface

water and cancer were published

subsequent to the 1994 proposed rule

and the 1992 meta-analysis. In general,

these new studies are better designed

than the studies published prior to the

1994 proposal. The new studies include

incidence of disease, interviews with

the study subjects, and better exposure

assessments. More evidence is available
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on bladder cancer for a possible

association to exposure to chlorinated

surface water than other cancer sites.

Because of the limited data available for

other cancer sites such as colon and

rectal cancer, the RIA focuses on

bladder cancer.

Based on the best studies, a range of

potential risks was developed through

the use of the population attributable

risk (PAR) concept. Epidemiologists use

PAR to quantify the fraction of disease

burden in a population (e.g., bladder

cancer) that could be eliminated if the

exposure (e.g., chlorinated drinking

water) was absent. PAR (also referred to

as attributable risk, attributable portion,

or etiologic fraction) provides a

perspective on the potential magnitude

of risks associated with various

exposures under the assumption of

causality. For example, the National

Cancer Institute estimates that there will

be 54,500 new cases of bladder cancer

in 1997. If data from an epidemiological

study analyzing the impact of

consuming chlorinated drinking water

reports a PAR of 1 percent, it can be

estimated that 545 (54,500 × .01)

bladder cancer cases in 1997 may be

attributable to chlorinated drinking

water.

Under the Executive Order #12866

that requires EPA to conduct a RIA, EPA

has chosen to estimate an upper bound

bladder cancer risk range for chlorinated

drinking water using the PAR. EPA

suggested this approach in the 1998

NODA (EPA, 1998a). While EPA

recognizes the limitations of the current

epidemiologic data base for making

these estimates, the Agency considers

the data base reasonable for use in

developing an upper bound estimate of

bladder cancer risk for use in the RIA.

In light of the toxicological evidence,

EPA recognizes that the risks from

chlorinated drinking water may be

considerably lower than those derived

from the currently available

epidemiological studies. EPA selected

studies for inclusion in the quantitative

analysis if they contained the pertinent

data to perform a PAR calculation and

met all three of the following criteria:

1. The study was a population-based,

case-control, or cohort study conducted

to evaluate the relationship between

exposure to chlorinated drinking water

and incidence of cancer cases, based on

personal interviews; (all finally selected

studies were population-based, casecontrol studies)

2. The study was of high quality and

well designed (e.g., adequate sample

size, high response rate, adjusted for

known confounding factors); and,

3. The study had adequate exposure

assessments (e.g., residential histories,

actual THM data).

Using the above criteria, five bladder

cancer studies were selected for

estimating the range of PARs.

• Cantor, et al., 1985;

• McGeehin, et al., 1993;

• King and Marrett, 1996;

• Freedman, et al., 1997; and

• Cantor, et al., 1998.

The PARs from the five bladder

cancer studies ranged from 2 percent to

17 percent. These values were derived

from measured risks (Odds Ratio and

Relative Risk) based on the number of

years exposed to chlorinated surface

water. Because of the uncertainty in

these estimates, it is possible that the

PAR could also be zero. The

uncertainties associated with these PAR

estimates are large due to the common

prevalence of both the disease (bladder

cancer) and exposure (chlorinated

drinking water).

In order to apply these PAR estimates

to the U.S. population to estimate the

number of bladder cancer cases

attributable to DBPs in drinking water,

a number of assumptions must be made.

These include: (1) that the study

populations selected for each of the

cancer epidemiology studies are

reflective of the entire population that

develops bladder cancer; (2) that the

percentage of those cancer cases in the

studies exposed to chlorinated drinking

water are reflective of the bladder

cancer cases in the U.S.; (3) that DBPs

were the only carcinogens in these

chlorinated surface waters; and (4) that

the relationship between DBPs in

chlorinated drinking water exposure

and bladder cancer is causal.

The last of these assumptions is

perhaps the most open to question. As

noted in the March 1998 NODA, the

results of the studies are inconsistent. In

light of these concerns, the Agency

agrees that causality between exposure

to chlorinated water and bladder cancer

has not been established and that the

number of cases attributable to such

exposures could be zero.

Based on the estimate of 54,500 new

bladder cancer cases per year nationally,

as projected by the National Cancer

Institute for 1997, the numbers of

possible bladder cancer cases per year

potentially associated with exposures to

DBPs in chlorinated drinking water

estimated from the five studies range

from 1,100 (0.02 × 54,500) to 9,300 (.17

× 54,500) cases. As noted above, due to

the uncertainty in these estimates, the

number of cases could also be zero. In

making these estimates it is necessary to

assume that these bladder cancer cases

are attributed to DBPs in chlorinated

surface water, even though the studies

examined the relationship between

chlorinated surface water and bladder

cancer. This derived range is not

accompanied by confidence intervals

(C.Is), but the C.Is. are likely to be very

wide. EPA believes that the mean risk

estimates from each of the five studies

provides a reasonable estimate of the

potential range of risk suggested by the

different epidemiological studies. Table

IV–8 contains a summary of the risk

estimates from the 1994 draft RIA and

the estimates derived from the more

recent analysis.

A related analysis based on odds

ratios was conducted to derive a range

of plausible estimates for cancer

epidemiologic studies (EPA, 1998n).

This analysis was also based on bladder

cancer studies (the five studies cited

above in addition to Doyle et al. 1997).

For the purpose of this exercise, the

annual U.S. expected number of 47,000

bladder cancers cited by Morris et

al.(1992) was used to calculate estimates

of the cancers prevented. The number of

cancers attributable to DBP exposure

was estimated not to exceed 2,200–

9,900 per year and could include zero.

As would be expected from related

analysis performed in the same data,

this range is similar to the 1,100–9300

PAR range. EPA has used the 1100–9300

PAR range for the RIA.

TABLE IV–8.—NUMBER OF CANCER CASES ATTRIBUTABLE TO DBPS: COMPARISON OF ESTIMATES IN 1994 AND 1998

1994 estimates 1998 estimates

Number of New Bladder Cancer Cases/Year ..................................... Approx. 50,000 ................... 54,500.

Number of Estimated Deaths Due to Bladder Cancer/Year ............... Did not state ....................... 12,500.

Attributable to DBPs in Drinking Water

Data Source ........................................................................................ >15 studies ......................... 5 studies that meet specific criteria.

Causality .............................................................................................. No ....................................... No.

Percent Attributable to DBPs .............................................................. Did not state ....................... 2% to 17%.
69440 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

TABLE IV–8.—NUMBER OF CANCER CASES ATTRIBUTABLE TO DBPS: COMPARISON OF ESTIMATES IN 1994 AND 1998—

Continued

1994 estimates 1998 estimates

Number of Cancer Cases Attributable to DBPs:

Estimated Using Toxicological Data ............................................ Less than 1* ....................... Zero to 100.**

Estimated Using Epidemiological Data ........................................ Over 10,000*** ................... Zero to 9,300.****

*Based on maximum likelihood estimates of risk from THMs.

**Based on IRIS 95th percent C.I. estimates of risk from THMs.

***Indicates rectal and bladder cancer cases.

****Indicates only bladder cancer cases.

The current benefits analysis is

structured in roughly the same manner

as that presented in the 1994 RIA. The

baseline cancer risks could lie anywhere

from zero to 100 cases per year based on

toxicological data; and zero to 9,300

cases per year based on epidemiological

data. Consequently, the task is to assess

the economic benefit of the final Stage

1 DBPR in the face of this broad range

of possible risk.

4. Exposure Reduction Analysis

EPA predicted exposure reductions

due to the current Stage 1 DBPR relative

to the present baseline. EPA used the

concentration of TTHMs as a marker to

measure the exposure to the range of

DBPs because data are available on the

baseline occurrence and formation of

TTHMs. There are limited data on the

total mix of byproducts in drinking

water. Therefore, the reduction in

TTHMs is assumed to reflect the

reduction in exposure to all DBPs. To

determine the change in exposure, it is

necessary to estimate the pre-Stage 1

baseline average TTHM concentration

and the post Stage 1 average TTHM

concentration. The difference in the preand post-Stage 1 TTHM concentrations

reflect the potential reduction in

TTHMs and thus in DBPs.

As described previously, the

estimated pre-Stage 1 TTHM weighted

average concentration is 44 μg/L for all

system sizes and types of systems. The

post Stage 1 TTHM concentrations for

each system category were estimated

based on the technology compliance

forecasts previously discussed and

estimated reductions in TTHM levels

depending upon technology. The postStage 1 TTHM weighted average

concentration is estimated at 33 μg/L.

This represents a 24 percent reduction

in TTHM levels resulting from the Stage

1 DBPR. Further details of the above

analysis is described in the RIA for the

Stage 1 DBPR (USEPA, 1998g).

5. Monetization of Health Endpoints

The range of potential benefits from

the Stage 1 DBPR can be estimated by

applying the monetary values for fatal

and nonfatal bladder cancer cases with

the estimate of the number of bladder

cancer cases reduced by the rule. The

following assumptions are used to

estimate the range of potential benefits:

• An estimate of the number of

bladder cancer cases attributable to

DPBs in drinking water ranging from 0

to 9,300 annually.

• A 24 percent reduction in exposure

to TTHMs due to the Stage 1 DBPR (75

percent CI of 19 to 30 percent) will

result in an equivalent reduction in

bladder cancer cases

• A value per statistical life saved for

fatal bladder cancers represented by a

distribution with a mean of $5.6 million

• A willingness to pay to avoid a

nonfatal case of bladder cancer

represented by a distribution with a

mean of $587,500

Using the low end of the risk range of

0 bladder cancer cases attributable to

DBPs results in a benefits estimate of $0.

To calculate the high end of the range,

the 9,300 estimate of attributable cases

is multiplied by the percent reduction

in exposure to derive the number of

bladder cancer cases reduced (9,300 ×

.24 = 2,232 bladder cancer cases

reduced). This assumes a linear

relationship between reduction in

TTHMs concentrations and reduction in

cancer risk (e.g., 24 percent reduction in

TTHMs concentration is associated with

a 24 percent reduction in cancer risk).

Assuming 23 percent of the bladder

cancer cases end in fatality and 77

percent are nonfatal, the number of fatal

bladder cancer cases reduced is 513

(2,232 × .23) and the number of nonfatal

bladder cancer cases is 1,719 (2,232 ×

.77). Based on the valuation

distributions described above, the

estimate of benefits at the mean

associated with reducing these bladder

cancer cases is approximately $4 billion.

It should be noted that these estimates

do not include potential benefits from

reducing other health effects (e.g, colon/

rectal cancer and reproductive

endpoints) that cannot be quantified at

this time. As a result, EPA believes that

the potential benefits discussed in

today’s rule may be a substantial

underestimate of potential benefits that

will be realized as a consequence of

today’s action. While the low end of the

range cannot extend below $0, it is

possible that the high end of the range

could extend beyond $4 billion if the

other reductions in risk could be

quantified and monetized. No discount

factor has been applied to these

valuations, although there is likely to be

a time lag between compliance with the

rule and the realization of benefits.

Given this wide range of potential

benefits and the uncertainty involved in

estimating the risk attributable to DBPs,

EPA undertook five different

approaches to assessing the net benefits

of the Stage 1 DBPR. These approaches

are described in the net benefits section

and should be considered both

individually and in the aggregate.

E. Net Benefits Analysis

The potential economic benefits of the

Stage 1 DBPR derive from the increased

level of public health protection and

associated decreased level of risk. The

quantification of the benefits resulting

from DBP control is complicated by the

uncertainty in the understanding of the

health risks. Epidemiological studies,

referred to previously, suggest an

association between bladder cancer and

exposure to chlorinated surface water;

however, these risks are uncertain. The

lowest estimate in the selected

epidemiological studies of the number

of new bladder cancer cases per year

attributable to chlorinated surface water

is 1,100 cases, while the highest is 9,300

cases. EPA recognizes that while these

risks may be real, they also could be

zero. Assessment of risks based only on

toxicological data for THMs, indicate a

much lower risk (2 cancer cases per year

at the most likely estimate, to about 100

cases per year using the 95 percent

confidence level upper bound), but

THMs represent only a few of the many

DBPs in drinking water.

EPA explored several alternative

approaches for assessing the benefits of

the Stage 1 DBPR: Overlap of Benefit

and Cost Estimates; Minimizing Total

Social Losses; Breakeven Analysis;
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Household Costs; and Decision-Analytic

Model. A summary of the analysis of

each approach is presented below. More

detailed descriptions are described in

the RIA (USEPA, 1998g).

Overlap of Benefit and Cost Estimates.

One method to characterize net benefits

is to compare the relative ranges of

benefits and costs. Conceptually, an

overlap analysis tests whether there is

enough of an overlap between the range

of benefits and the range of costs for

there to be a reasonable likelihood that

benefits will exceed costs. In a

theoretical case where the high end of

the range of benefits estimates does not

overlap the low end of the range of cost

estimates, a rule would be difficult to

justify based on traditional benefit-cost

rationale.

For the Stage 1 DBPR, the overlap

analysis (Figures IV–1a and IV–1b)

show that there is substantial overlap in

the estimates of benefits and costs. The

range of quantified benefits extends

from zero to over $4 billion. The zero

end of the range of estimated benefits

represents the possibility that there is

essentially no health benefit from

reducing exposure to DBPs. The other

end of the range assumes there are 9,300

bladder cancer cases per year

attributable to DBPs and there is a 24

percent annual reduction in exposure

with the promulgation of the rule,

resulting in avoidance of 2,232 cases.

Assuming that number of avoided cases,

approximately 513 would have been

fatalities and would result in a cost

savings of approximately $3 billion

(each avoided fatality results in a cost

savings of $5.6 million). Additionally,

1,719 non-fatal cases avoided would

result in a cost savings of approximately

$1 billion (each avoided non-fatal case

results in a cost savings of $0.6 million).

The sum of the cost savings is

approximately $4 billion. The high end

of the benefits range could potentially

be higher if other health damages are

avoided. The range of cost estimates is

significantly smaller, ranging from $500

million to $900 million annually.

Although these cost estimates have

uncertainty, the degree of uncertainty is

of little consequence to the decisions

being made given the scale of the

uncertainty for the benefits.

Figure IV–1b, on the other hand,

indicates that while the quantified

benefits could exceed the costs, there is

the possibility that there could be

negative net benefits if there were no

health benefits.

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Figure IV–1a Overlap of Estimated

Benefits and Costs of the Stage 1 DBPR

Figure IV–1b Overlap of the Ranges of

the Estimated Benefits and Costs of the

Stage 1 DBPR

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Minimizing Total Social Losses

Analysis. Minimizing Total Social

Losses analysis, sometimes called

‘‘minimizing regrets’’ analysis, is a

decision-aiding tool that is suited for

use in situations where it is impossible

to pin down the exact nature and extent

of a risk. The basic premise of

Minimizing Total Social Losses analysis

is to estimate total social costs for policy

alternatives over a range of plausible

risk scenarios. The actual, or ‘‘true’’ risk

is unknowable, so instead this analysis

asks what range and level of risks could

be true, and then evaluates the total

costs to society if particular risk levels

within that range turned out to be the

‘‘true’’ value. Total social costs include

both the cost to implement the policy

option, plus costs related to residual

(i.e., remaining) health damages at each

risk level after implementation of the

policy option.

Under this analysis the ‘‘total social

costs’’ (water treatment costs plus costs

of health damages still remaining after

treatment) are calculated for three

regulatory alternatives (No Action, Stage

1, and Strong Intervention—otherwise

known as the proposed Stage 2

requirements of the 1994 proposal)

across a range of risk scenarios (< 1; 100;

1,000; 2,500; 5,000; 7,500; and 10,000

attributable bladder cancer cases

annually). Total social costs for each

regulatory alternative for different risk

assumptions are presented in Table IV–

9. The results indicate that the Stage 1

DBPR has the least social cost among

the three alternatives analyzed across

the range of risks from 2,500 through

7,500 attributable bladder cancer cases

annually.

Total ‘‘social loss’’ for each risk

scenario are also indicated in Table IV–

9. The ‘‘social loss’’ is the cost to society

of making a wrong choice among the

regulatory alternatives. It is computed as

the difference between the total social

cost (water treatment cost plus

remaining health damages) of an

alternative at a given risk scenario and

the total social cost of the best

alternative (least total social cost

alternative for that risk scenario). The

regulatory alternatives across the

different risk levels can also be

compared to see which alternative

minimizes the maximum potential loss.

The best alternative, by this ‘‘mini-max’’

criteria, would be the one in which the

upper bound of potential losses is

smallest.

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Under the Stage 1 DBPR alternative,

the worst loss that could happen would

occur if the lowest end of the risk range

is true. This would result in total social

losses of $0.7 billion per year. It is

concluded that the maximum potential

loss of the Stage 1 alternative is smaller

than that of No Action ($4.1 billion) by

a factor of 6 and smaller than that of

Strong Intervention ($2.9 billion) by a

factor of 4. Thus, the Stage 1 DBPR is

the best of the 3 alternatives at

minimizing the maximum social loss.

The 1994 Reg. Neg. and 1997 M–DBP

Advisory Committees implicitly applied

this type of ‘‘minimizing maximum

loss’’ framework when developing and

evaluating the DBP regulatory options.

In the face of large uncertainty regarding

risk from DBPs, they decided that a

moderate response, relying on the more

cost-effective of the available treatment

methods was appropriate as an interim

step until more information on risk

becomes available.

Break Even Analysis. Breakeven

analysis represents another approach to

assessing the benefits of the Stage 1

DBPR given the scientific uncertainties.

Breakeven is a standard benchmark of

cost effectiveness and economic

efficiency, and is essentially the point

where the benefits of the Stage 1 DBPR

are equal to the costs. Normally, the

benefits and costs of an option are

calculated separately and then

compared to assess whether and by

what amount benefits exceed costs. In

the case of the Stage 1 DBPR,

independently estimating benefits is

difficult, if not impossible, because of

the 10,000-fold uncertainty surrounding

the risk. Instead, the breakeven analysis

works backwards from those variables

that are less uncertain. In this case,

implementation costs for the rule and

the monetary value associated with the

health endpoints are used to calculate

what baseline risk and risk reduction

estimates are needed in order for the

benefits, as measured in avoided health

damages associated with bladder cancer,

to equal the costs.

Two important concepts for this

analysis are the cost of illness measure

and the willingness-to-pay measure. The

cost of illness measure includes medical

costs and lost wages associated with

being unable to work as a result of

illness. In comparison, willingness-topay measures how much one would pay

to reduce the risk of having all the

discomfort and costs associated with

nonfatal cancer if such an option

existed. The main difference between

these two methods is that willingnessto-pay incorporates pain and suffering,

as well as changes in behavior into the

valuation, while cost of illness does not.

EPA has estimated the cost of a nonfatal case of bladder cancer at $121,000

using the cost of illness method, and at

$587,500 using the willingness-to-pay

approach.

Assuming an annual cost of $701

million and assumptions about the

monetary value of preventing both fatal

and nonfatal bladder cancer cases, the

Stage 1 DBPR would need to reduce 438

bladder cancer cases per year using the

willingness-to-pay measure for nonfatal

cancers or 574 cases per year using the

cost of illness measure. If exposure is

reduced by 24 percent, the baseline

number of bladder cancer cases

attributable to DBPs in chlorinated

drinking water required to break even

would need to range from 1,820 to 2,390

new cases annually. Although these

values are well above the range

indicated by existing toxicological data

for THMs alone, they fall within the

attributable risk range suggested by the

epidemiological studies.

Household Cost Analysis. A fourth

approach for assessing the net benefits

of the Stage 1 DBPR is to calculate the

costs per household for the rule.

Household costs provide a common

sense test of benefit/cost relationships

and are another useful benchmark for

comparing the willingness-to-pay to

reduce the possible risk posed by DBPs

in drinking water. It is essentially a

household level breakeven analysis. It

works backwards from the cost to ask

whether the implied amount of benefits

(willingness-to-pay) needed to cover

costs is a plausible amount.

About 115 million households are

located in service areas of systems

affected by the Stage 1 DBPR. Of these

households, 71 million (62 percent) are

served by large surface water systems.

Approximately 4.2 million (4 percent)

are served by small surface water

systems. Large ground water systems

served 24 million households (21

percent) and small ground water

systems serve 15.7 million households

(14 percent).

All of the households served by

systems affected by the Stage 1 DBPR

will incur some additional costs (e.g.,

monitoring costs), even if the system

does not have to change treatment to

comply with the proposed rule. The

costs calculated below include both

monitoring and treatment costs.

The cumulative distribution of

household costs for all systems and by

each system type is displayed in Figures

IV–2a, IV–2b, IV–2c. The distributions

show that the large percentage of

households will incur small additional

costs, with a small portion of systems

facing higher costs. At the highest end

of the distribution, approximately 1,400

households served by surface water

systems in the 25–100 size range

switching to membrane technology will

face an average annual cost increase of

$400 per year ($33 per month).

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The households have been sorted into

three cost categories for the ease of

comparison (Table IV–10). The first

category includes households with a

cost increase of less than $12 per year,

less than $1 per month. The second

category contains households with costs

greater than $12 per year, but less than

$120 per year ($10 per month). The

third category includes households with

cost increases greater than $120 per year

to $400 per year ($33 per month).

Across all system categories (see

Figure IV–2a), 95 percent of the

households (110.1 million) fall within

the first category and will incur less

than $1 per month additional costs due

to the Stage 1 DBPR. An additional 4

percent (4.4 million) are in the second

category at between $1 and $10 per

month cost increase and 1 percent (1.0

million) are in the highest category

($10–$33.40 per month).

For households served by large

surface water systems (Figure IV–2b), 98

percent will incur less than $1 per

month, 2 percent will incur between $1

and $10 per month, and 0.03 percent

will incur greater than $10 per month.

The highest cost ($125 annually, $10.40

monthly) is faced by households served

by systems in the 10,000 to 25,000 size

range implementing membrane

technology.

For households served by small

surface water systems (Figure IV–2c), 71

percent will incur less than $1 per

month, 28 percent will incur between

$1 and $10 per month, and 1 percent

will incur greater than $10 per month.

The highest cost ($400 annually, $33

monthly) is faced by households served

by systems in the 25–100 size range

implementing membrane technology.

For households served by large

ground water systems (Figure IV–2b), 95

percent will incur less than $1 per

month, 4 percent will incur between $1

and $10 per month, and 1 percent will

incur greater than $10 per month. The

highest cost ($125 annually, $10.40

monthly) is faced by households served

by systems in the 10,000 to 25,000 size

range implementing membrane

technology.

For households served by small

ground water systems (Figure IV–2c), 91

percent will incur less than $1 per

month, 5 percent will incur between $1

and $10 per month, and 4 percent will

incur greater than $10 per month. The

highest cost ($357 annually, $29.75

monthly) is faced by households served

by systems in the 25–100 size range

implementing membrane technology.

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In the small proportion of systems

where household costs are shown to be

much greater—up to several hundreds

of dollars per year—these results are

driven by the assumption that

membrane technologies will be the

selected treatment, as noted above.

Additionally, two points must be made:

(1) a number of these systems may find

less expensive means of compliance

(e.g., selection of alternative source

water, purchased water, or

consolidation with other systems); and

(2) if these systems do install

membranes, they may receive additional

water quality and/or compliance

benefits beyond those associated with

DBPs. For example, because membranes

are so effective, systems that install

membranes are likely to incur lower

compliance costs for future

rulemakings.

Given the uncertain nature of the risks

associated with DBPs, household costs

provide a common sense estimate of

willingness-to-pay to reduce the risks:

Would the average household (95

percent of households) be willing to pay

less than $1 per month ($12 per year) to

reduce the potential risks posed by

DBPs?

Willingness to pay studies are not

available to directly answer this

question. Taking the $1 per month

figure as a measure of implied public

health benefit at the household level, it

is useful to ask what benefits can be

identified that could balance a $1 per

month expenditure. First, it is entirely

possible that there is much more than a

dollar-a-month’s worth of tangible

health benefit based on reduced risk of

bladder cancer alone. Second, the broad

exposure to DBPs and the possible

health effects involved offer the

possibility that there are significant

additional health benefits of a tangible

nature. However, the agency recognizes

that in the small percentage of situations

where the costs per household is

between $120 to $400 per year, this may

indeed be a difficult financial burden to

meet (e.g., may exceed household

willingness-to-pay).

Finally, the preventive weighing and

balancing of public health protection

also provides a margin of safety—a

hedge against uncertainties. Recent

survey research conducted in the

drinking water field provides

compelling empirical evidence that the

number one priority of water system

customers is the safety of their water.

Although definitive economic research

has not been performed to investigate

the extent of household willingness-topay for such a margin of safety, there is

strong evidence from conventional

customer survey research implying a

demand for this benefit.

Decision Analytical model. The RIA

also discusses a fifth type of analysis in

which probability functions are used to

model the uncertainty surrounding

three variables (rule cost, exposure

reduction, and attributable bladder

cancer risk) in order to derive a

probability distribution function for

annual net benefit of the Stage I rule.

Because there is little actual data on

these probability functions, this

approach should be considered

illustrative only. It is not discussed

further here, but is discussed in Chapter

6 of the RIA for the Stage 1 DBPR (EPA,

1998g).

While any one of the above analytical

approaches by itself may not make a

definitive case for the benefit-cost

effectiveness for the Stage 1 DBPR,

taken collectively EPA believes they

indicate that the Stage 1 DBPR benefits

to society will exceed the costs. The

monetized benefits in the five

alternatives represent only a portion of

total potential benefits. Benefits

associated with other cancer sites (rectal

and colon) and other health endpoints

(such as developmental and

reproductive effects) could not be

quantified at this time, and while they

could be nil, they also could be quite

large. Based on a careful weighing of the

projected costs against the potential

quantified and non-quantified benefits,

EPA has determined that the benefits of

the rule justify its costs.

F. Summary of Comments

Many commenters expressed concern

about the wide range of benefits given

the high national cost of the rule. EPA

has revised the benefits analysis; and

while the associated uncertainties

remain large, EPA believes the benefits

of the Stage 1 DBPR justify its costs.

Other commenters expressed concern

with using the data from Morris et al.

(1992) for quantifying benefits. They

believed that the studies used in the

meta-analysis were different in design

and thus not appropriate to use in metaanalysis. In addition the commenters

believed that potential confounding

factors or bias may not have been

adequately controlled in the selected

studies. Others believed there was

utility in using the meta-analysis to

provide a perspective on the potential

cancer risks. Several commenters were

supportive of the Poole (1997)

evaluation of the Morris et al. (1992)

meta-analysis stating that they

concurred that the Morris analysis

should not be used for estimating

benefits for the Stage 1 DBPR. Other

commenters suggested a better use of

the resources used to complete the

Poole report would have been to

complete a new meta-analysis using the

more recent studies that have come out

since the Morris et al. (1992) metaanalysis and that the Poole evaluation

did not advance the science in this area.

Several commenters were critical of the

PAR analysis (described in EPA, 1998a)

used to characterize the potential

baseline bladder cancer cases per year

that could be attributable to exposure to

chlorinated drinking water. They

present several arguments including:

questioning whether such an analysis is

warranted given the inconsistencies in

the studies used to complete the

analysis; stating that the use of the term

upper bound of any suggested risk of

cancer is inappropriate because this

does not include the potential risks from

other cancer sites such as colon and

rectal; using the assumption of causality

is not warranted given the

inconsistencies in the studies used to

complete the PAR analysis; and the PAR

analysis should include a lower bound

estimate of zero.

EPA agrees that the use of the Morris

et al. (1992) meta-analysis for estimating

benefits is not appropriate for the

reasons cited by commenters (e.g.,

studies of different designs and

discussed in more detail in the 1998

DBP NODA). EPA is currently

considering whether a new metaanalysis that uses the most recent

epidemiology studies would be useful

for the Stage 2 rulemaking. The Poole

(1997) report considered a meta analysis

of the available data. Poole used several

techniques to evaluate the data and

included several new studies that were

available at the time of his analysis.

Poole concluded that the cancer

epidemiology data considered in his

evaluation should not be combined into

a single summary estimated and that the

data had limited utility for risk

assessment purposes. More recent

studies by Cantor et al. (1998), Doyle et

al. (1997) and Freedman et al. (1997)

were not available at the time of his

evaluation.

EPA understands commenters

concerns with the PAR analysis,

especially concerns with assuming

‘‘causality’’ in the PAR evaluation when

it is stated in other sections of the

preamble that EPA does not believe

causality has been established. Even

though causality has not been

established, EPA is required to estimate

the potential impacts of major

regulations such as the DBP Stage 1

rule. The Agency believes it is

appropriate to conduct the PAR analysis

as described in the 1998 DBP NODA

(EPA, 1998a), to provide estimates of the
69452 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

potential risk that may need to be

reduced. EPA agrees that the use of the

term ‘‘upper bound of any suggested

risk’’ is not appropriate because there

are other potential risks that have not

been quantified that may contribute to

the overall risk estimates. In addition,

EPA agrees that the estimates of the

potential cancer cases should include

zero as this is a possibility given the

uncertainties in the data. EPA agrees

that several assumptions are made in

the analysis regarding the national

extrapolation of the results and that

there is insufficient information at this

time to validate these assumptions.

However, given the need to develop

national estimates of risk, EPA believes

it is appropriate to make these

assumptions in order to provide a

perspective on the potential risks from

exposure to chlorinated surface waters.

Commenters expressed concerns with

the high costs associated with systems

that must adopt alternative advanced

technologies, especially for small

systems. Since the 1994 proposal, the

projected national costs for the Stage 1

DBPR have dropped significantly (as

discussed above). This is mainly due to

the revised compliance forecast and

lower membrane technology costs. In

the revised compliance forecast, fewer

systems using surface water will need

advanced technologies to comply. This

shift to lesser use of advanced

technologies to comply with the Stage 1

DBPR also pertains to small systems

(those serving less than 10,000 people).

Commenters expressed concern for

the high costs associated with the Stage

2 DBPR and whether EPA would obtain

enough information to adequately

understand the risks that might be

avoided to justify such a rule. EPA

agrees that additional health effects

information is needed before

reproposing the Stage 2 DBPR and will

address this issue in the next round of

FACA deliberations. Based on new data

generated through research, EPA will

reevaluate the Stage 2 regulations and

re-propose, as appropriate.

V. Other Requirements

A. Regulatory Flexibility Act

1. Today’s Rule

Under the Regulatory Flexibility Act,

5 U.S.C. 601 et seq. (RFA), as amended

by the Small Business Regulatory

Enforcement Fairness Act, EPA

generally is required to conduct a

regulatory flexibility analysis describing

the impact of the regulatory action on

small entities as part of rulemaking.

However, under section 605(b) of the

RFA, if EPA certifies that the rule will

not have a significant economic impact

on a substantial number of small

entities, EPA is not required to prepare

a regulatory flexibility analysis.

Throughout the 1992–93 negotiated

rulemaking process for the Stage 1

DBPR and IESWTR and in the July 1994

proposals for these rules, a small PWS

was defined as a system serving fewer

than 10,000 persons. This definition

reflects the fact that the original 1979

standard for total trihalomethanes

applied only to systems serving at least

10,000 people. The definition thus

recognizes that baseline conditions from

which systems serving fewer than

10,000 people will approach

disinfection byproduct control and

simultaneous control of microbial

pathogens is different than that for

systems serving 10,000 or more persons.

EPA again discussed this approach to

the definition of a small system for these

rules in the 1998 DBP NODA (EPA,

1998a). EPA is continuing to define

‘‘small system’’ for purposes of this rule

and the IESWTR as a system which

serves fewer than 10,000 people.

The Agency has since proposed and

taken comment on its intent to define

‘‘small entity’’ as a public water system

that serves 10,000 or fewer persons for

purposes of its regulatory flexibility

assessments under the RFA for all future

drinking water regulations. (See

Consumer Confidence Reports Rule, 63

FR 7620, Feb. 13, 1998.) In that

proposal, the Agency discussed the

basis for its decision to use this

definition and to use a single definition

of small public water system whether

the system was a ‘‘small business’’,

‘‘small nonprofit organization’’, or

‘‘small governmental jurisdiction.’’ EPA

also consulted with the Small Business

Administration on the use of this

definition as it relates to small

businesses. Subsequently, the Agency

has used this definition in developing

its regulations under the Safe Drinking

Water Act. This approach is virtually

identical to the approach used in the

Stage 1 DBPR and IESWTR. Since, EPA

is not able to certify that the final Stage

1 DBPR will not have a significant

economic impact on a substantial

number of small entities, EPA has

completed a final RFA and will publish

a small entity compliance guidance to

help small entities comply with this

regulation.

2. Background and Analysis

The Regulatory Flexibility Act

requires EPA to address the following

when completing a final RFA: (1) state

succinctly the objectives of, and legal

basis for, the final rule; (2) summarize

public comments on the initial RFA, the

Agency’s assessment of those

comments, and any changes to the rule

in response to the comments; (3)

describe, and where feasible, estimate

the number of small entities to which

the final rule will apply; (4) describe the

projected reporting, record keeping, and

other compliance requirements of the

rule, including an estimate of the classes

of small entities that will be subject to

the requirements and the type of

professional skills necessary for

preparation of reports or records; and (5)

describe the steps the Agency has taken

to minimize the impact on small

entities, including a statement of the

reasons for selecting the chosen option

and for rejecting other options which

would alter the impact on small entities.

EPA has considered and addressed all

the above requirements in the

Regulatory Impact Analysis (RIA) for the

Stage 1 DBPR (EPA 1998g). The

following is a summary of the RFA.

The first requirement is discussed in

section I of today’s rule. The second,

third and fifth requirements are

summarized below. The fourth

requirement is discussed in V.B

(Paperwork Reduction Act) and the

Information Collection Requirement.

Number of Small Entities Affected.

EPA estimates that 69,491 groundwater

systems will be affected by the Stage 1

DBPR, with 68,171 (98%) of these

systems serving less than 10,000

persons. Of the 68,171 small systems

affected, EPA estimates that 8,323 (12%)

will have to modify treatment to comply

with the Stage 1 DBPR. Of these, 5,403

systems (8%) will use chloramines to

comply and 2,921 systems (4.3%) will

use membranes to comply. Use of these

technologies by small groundwater

systems will result in total capital costs

of $998 million and an annualized

treatment cost of $180 million.

EPA estimates that 6,560 surface

water systems will be affected by the

Stage 1 DBPR, with 5,165 (79%) of these

systems serving less than 10,000

persons. It is estimated that 3,616 (70%)

of these small systems will have to

modify treatment to comply with the

Stage 1 DBPR and 3,459 (67%) of these

systems will use a combination of

enhanced coagulation, chloramines, and

ozone, while another 157 systems (3%)

will use membranes. Use of these

technologies by small surface water

systems will result in total capital costs

of $243 million and an annualized

treatment cost of $46 million.

EPA has included several provisions

which will reduce the economic burden

of compliance for these small systems.

These requirements, discussed in

greater detail in the RIA (EPA, 1998g),

include:
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69453

—Less routine monitoring. Small

systems are required to monitor less

frequently for such contaminants as

TTHMs and HAA5. Also, ground

water systems (the large majority of

small systems) are required to monitor

less frequently than Subpart H

systems (surface water systems and

groundwater under the direct

influence of surface water) of the

same size.

—Extended compliance dates. Systems

that use only ground water not under

the direct influence of surface water

serving fewer than 10,000 people have

60 months from promulgation of this

rule to comply. This is in contrast to

large Subpart H systems which have

36 months to comply. These extended

compliance dates will allow smaller

systems to learn from the experience

of larger systems on how to most cost

effectively comply with the Stage 1

DBPR. In addition, larger systems will

generate a significant amount of

treatment and cost data from the ICR

and in their efforts to achieve

compliance with the Stage 1

requirements. EPA intends to

summarize this information and make

it available through guidance manuals

(i.e., the Small Entities Guidance

Manual). EPA believes this

information will assist smaller

systems in achieving compliance with

the Stage 1 DBPR.

3. Summary of Comments

Several commenters expressed

concern with the significant economic

burden that the Stage 1 DBPR would

place on small systems. Other

commenters suggested more flexibility

be given for small systems and that a

longer compliance period for small

systems should be included in the final

Stage 1 DBPR. Several commenters

suggested small systems should not be

included in the final Stage 1 DBPR

because the costs for implementing the

rule would exceed the potential benefits

for these systems.

EPA understands commenters’

concerns with the potential significant

economic burden on small systems.

Because of this potential significant

impact, EPA has provided several

requirements which will reduce the

burden on these systems. These

requirements which are discussed above

and also in greater detail in the RIA

(EPA, 1998g) include: (1) less routine

monitoring; and (2) extended

compliance dates. EPA also believes

small systems can reduce their

economic burden by; (1) consolidation

with larger systems; (2) using money

from the State revolving fund loans; and

(3) using variances and exemptions

when needed. EPA considered an

option in the development of the final

rule for large systems to have MCLs of

80 ug/L for TTHMs and 60 ug/L for

HAAs and for small systems to have a

simple TTHM standard of 100 ug/L.

This option was rejected because

allowing small systems to comply with

a different MCL level would not

adequately protect the health of the

population served by these systems.

EPA did not consider excluding small

systems from the Stage 1 DBPR, because

these systems do not currently have any

standards for DBPs and the Agency

believed there was a public health

concern that needed to be addressed.

For a more detailed description of the

alternatives considered in the

development of the final rule see the

final RIA (EPA, 1998g) or the final

Unfunded Mandates Reform Act

Analysis for the Stage 1 DBPR (EPA,

1998o).

B. Paperwork Reduction Act

The Office of Management and Budget

(OMB) has approved the information

collection requirements contained in

this rule under the provisions of the

Paperwork Reduction Act, 44 U.S.C.

3501 et seq. and has assigned OMB

control number 2040–0204.

The information collected as a result

of this rule will allow the States and the

EPA to evaluate PWS compliance with

the rule. For the first three years after

promulgation of the Stage 1 DBPR, the

major information requirements pertain

to preparation for monitoring activities,

and for compliance tracking. Responses

to the request for information are

mandatory (Part 141). The information

collected is not confidential.

EPA is required to estimate the

burden on PWS for complying with the

final rule. Burden means the total time,

effort, or financial resources expended

by persons to generate, maintain, retain,

or disclose or provide information to or

for a Federal agency. This includes the

time needed to review instructions;

develop, acquire, install, and utilize

technology and systems for the purposes

of collecting, validating, and verifying

information, processing and

maintaining information, and disclosing

and providing information; adjust the

existing ways to comply with any

previously applicable instructions and

requirements; train personnel to be able

to respond to a collection of

information; search data sources;

complete and review the collection of

information; and transmit or otherwise

disclose the information.

EPA estimates that the annual burden

on PWS and States for reporting and

recordkeeping will be 314,471 hours.

This is based on an estimate that there

will be 4,631 respondents on average

per year who will need to provide about

9,449 responses and that the average

response will take 33 hours. The annual

labor cost is estimated to be about $12

million. In the first 3 years after

promulgation of the rule, only labor

costs are incurred. The costs are

incurred for the following activities:

reading and understanding the rule;

planning; and training.

An Agency may not conduct or

sponsor, and a person is not required to

respond to a collection of information

unless it displays a currently valid OMB

control number. The OMB control

numbers for EPA’s regulations are listed

in 40 CFR Part 9 and 48 CFR Chapter

15. EPA is amending the table in 40 CFR

Part 9 of currently approved ICR control

numbers issued by OMB for various

regulations to list the information

requirements contained in this final

rule. This ICR was previously subject to

public notice and comment prior to

OMB approval. As a result, EPA finds

that there is ‘‘good cause’’ under section

553 (b)(B) of the Administrative

Procedures Act (5 U.S.C. 553 (b) (B)) to

amend this table without prior notice

and comment. Due to the technical

nature of the table, further notice and

comment would be unnecessary.

C. Unfunded Mandates Reform Act

1. Summary of UMRA Requirements

Title II of the Unfunded Mandates

Reform Act of 1995 (UMRA), Public

Law 104–4, establishes requirements for

Federal agencies to assess the effects of

their regulatory actions on State, local,

and tribal governments and the private

sector. Under UMRA section 202, EPA

generally must prepare a written

statement, including a cost-benefit

analysis, for proposed and final rules

with ‘‘Federal mandates’’ that may

result in expenditures to State, local,

and tribal governments, in the aggregate,

or to the private sector, of $100 million

or more in any one year. Before

promulgating an EPA rule, for which a

written statement is needed, section 205

of the UMRA generally requires EPA to

identify and consider a reasonable

number of regulatory alternatives and

adopt the least costly, most costeffective or least burdensome alternative

that achieves the objectives of the rule.

The provisions of section 205 do not

apply when they are inconsistent with

applicable law. Moreover, section 205

allows EPA to adopt an alternative other

than the least costly, most cost effective

or least burdensome alternative if the

Administrator publishes with the final
69454 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

rule an explanation on why that

alternative was not adopted.

Before EPA establishes any regulatory

requirements that may significantly or

uniquely affect small governments,

including tribal governments, it must

have developed, under section 203 of

the UMRA, a small government agency

plan. The plan must provide for

notification to potentially affected small

governments, enabling officials of

affected small governments to have

meaningful and timely input in the

development of EPA regulatory

proposals with significant Federal

intergovernmental mandates; and

informing, educating, and advising

small governments on compliance with

the regulatory requirements.

2. Written Statement for Rules With

Federal Mandates of $100 Million or

More

EPA has determined that this rule

contains a Federal mandate that may

result in expenditures of $100 million or

more for State, local, and tribal

governments, in the aggregate, and the

private sector in any one year.

Accordingly, EPA has prepared, under

section 202 of the UMRA, a written

statement addressing the following

areas: (1) authorizing legislation; (2)

cost-benefit analysis including an

analysis of the extent to which the costs

to State, local and Tribal governments

will be paid for by the federal

government; (3) estimates of future

compliance costs and disproportionate

budgetary effects; (4) macro-economic

effects; and (5) a summary of EPA’s

consultation with State, local, and

Tribal governments, and a summary of

their concerns, and a summary of EPA’s

evaluation of their concerns. A more

detailed description of this analysis is

presented in EPA’s Unfunded Mandates

Reform Act Analysis for the Stage 1 DBP

Rule (EPA, 1998o) which is included in

the docket for this rule.

a. Authorizing Legislation. Today’s

rule is promulgated pursuant to Section

1412(b)(2) of the 1996 amendments to

the SDWA; paragraph C of this section

establishes a statutory deadline of

November 1998 to promulgate this rule.

This rule supersedes the TTHM Rule

(EPA, 1979). In addition, the Stage 1

DBP rule is closely integrated with the

IESWTR, which also has a statutory

deadline of November 1998.

b. Cost Benefit Analysis. Section IV

discusses the cost and benefits

associated with the Stage 1 DBP rule.

Also, the EPA’s Regulatory Impact

Analysis of the Stage 1 Disinfectants/

Disinfection Byproducts Rule (EPA,

1998g) contains a detailed cost benefit

analysis. Today’s rule is expected to

have a total annualized cost of

approximately $701 million using a 7

percent cost of capital. The analysis

includes both qualitative and monetized

benefits for improvements to health and

safety. Because of scientific uncertainty

regarding the exposure assessment and

the risk assessment for DBPs, the

Agency has used five analytical

approaches to assess the benefits of the

Stage 1 DBP. These analyses were based

on the quantification of bladder cancer

health damages avoided. However, this

rule may also reduce colon and rectal

cancers, as well as decrease adverse

reproductive and developmental effects.

This would further increase the benefits

of this rule.

Various Federal programs exist to

provide financial assistance to State,

local, and Tribal governments in

complying with this rule. The Federal

government provides funding to States

that have primary enforcement

responsibility for their drinking water

programs through the Public Water

Systems Supervision Grants program.

Additional funding is available from

other programs administered either by

EPA or other Federal agencies. These

include the Drinking Water State

Revolving Fund (DWSRF) and Housing

and Urban Development’s Community

Development Block Grant Program. For

example, SDWA authorizes the

Administrator of the EPA to award

capitalization grants to States, which in

turn can provide low cost loans and

other types of assistance to eligible

public water systems. The DWSRF

assists public water systems with

financing the costs of infrastructure

needed to achieve or maintain

compliance with SDWA requirements.

Each State will have considerable

flexibility to determine the design of its

program and to direct funding toward

its most pressing compliance and public

health protection needs. States may

also, on a matching basis, use up to ten

percent of their DWSRF allotments for

each fiscal year to assist in running the

State drinking water program.

c. Estimates of Future Compliance

Costs and Disproportionate Budgetary

Effects. To meet the UMRA requirement

in section 202, EPA analyzed future

compliance costs and possible

disproportionate budgetary effects. The

Agency believes that the cost estimates,

indicated above and discussed in more

detail in Section IV of this rule,

accurately characterize future

compliance costs of the rule.

In regard to the disproportionate

impacts, EPA considered available data

sources in analyzing the

disproportionate impacts upon

geographic or social segments of the

nation or industry. This analysis was

difficult because impacts will most

likely depend on a system’s source

water characteristics and this data is not

available for all systems. However, it

should be noted that the rule uniformly

protects the health of all drinking water

system users regardless of the size or

type of system. Further analysis

revealed that no geographic or social

segment patterns were likely for this

rule. One observation is that the

historical pattern of development in this

country led most large cities to be

developed near rivers and other bodies

of water useful for power,

transportation, and drinking water. To

the extent that this rule affects surface

water, it in most ways reflects the

distribution of population and

geography of the nation. No rationale for

disproportionate impacts by geography

or social segment was identified. This

analysis, therefore, developed three

other measures: reviewing the impacts

on small systems versus large systems;

reviewing the costs to public versus

private water systems; and reviewing

the household costs of the final rule.

First, the national impacts on small

systems (those serving fewer than

10,000 people) versus large systems

(those serving 10,000 people or more) is

indicated in Table V–1. The higher cost

to the small ground water systems is

mostly attributable to the large number

of these types of systems (i.e. there are

68,171 small ground water systems,

1,320 large ground water systems, 5,165

small surface water systems, and 1,395

large surface water surface water

systems).

TABLE V–1.—ANNUAL COST OF COMPLIANCE FOR SMALL AND LARGE SYSTEMS ($000)*

Small systems

(population

< 10,000)

Large systems

(population

≥ 10,000)

Surface Water Systems (All) .................................................................................................................................... $56,804 $278,321
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69455

TABLE V–1.—ANNUAL COST OF COMPLIANCE FOR SMALL AND LARGE SYSTEMS ($000)*—Continued

Small systems

(population

< 10,000)

Large systems

(population

≥ 10,000)

Ground Water System (All) ...................................................................................................................................... 218,062 130,651

Total .................................................................................................................................................................. 274,866 408,972

* Costs calculated at a 7 percent cost of capital and include one time start-up costs.

The second measure of

disproportionate impact evaluated is the

relative total costs to public versus

private water systems, by size. EPA

believes the implementation of the rule

affects both public and private water

systems equally, with the variance in

total cost by system size merely a

function of the number of affected

systems.

The third measure, household costs,

can also be used to gauge the impact of

a regulation and to determine whether

there are disproportionately high

impacts in particular segments of the

population. A detailed analysis of

household cost impacts by system size

and system type are presented in

Section IV.E. In summary, for large

surface water systems EPA estimates

that 98 percent of households will incur

costs of less than $1 per month while

0.3 percent of households will incur

costs greater than $10 per month. For

large groundwater systems, EPA

estimates that 95 percent of households

will incur costs of less than $1 per

month while 1.0 percent of households

will incur costs greater than $10 per

month. For small surface water systems

EPA estimates the 71 percent of

households will incur costs of less than

$1 per month while 1 percent of

households will incur costs of greater

than $10 per month. For small

groundwater systems EPA estimates that

91 percent of households will incur

costs of less than $1 per month while 4

percent of households will incur costs

of greater than $10 per month.

The household analysis tends to

overestimate the costs per household

because of the structure and

assumptions of the methodology. For

example, the highest per-household cost

would be incurred in a system using

membrane technology. These systems,

conversely, might seek less costly

alternatives such as point-of-use

devices, selection of alternative water

sources, or connecting into a larger

regional water system. The overall effect

is that costs are higher in smaller

systems, and a higher percentage of

those systems are publicly owned.

Smaller systems, however, represent a

larger portion of systems that are not in

compliance with existing regulations.

EPA believes that smaller systems

incurring the highest household costs

may also incur the highest reduction in

risk. This is because smaller systems

have not had to previously comply with

a TTHMs standard of 100 ug/L. In the

RIA, EPA estimates that on average,

small systems will achieve about twice

as much reduction in risk as achieved

by larger systems (EPA,1998g).

Based on the analysis above, EPA

does not believe there will be

disproportionate impacts on small

systems, public versus private systems,

or generally by household. A more

detailed description of this analysis is

presented in the EPA’s Unfunded

Mandates Reform Act Analysis for the

Stage 1 DBP Rule (EPA,1998o).

d. Macro-economic Effects. As

required under UMRA Section 202, EPA

is required to estimate the potential

macro-economic effects of the

regulation. Macro-economic effects tend

to be measurable in nationwide

econometric models only if the

economic impact of the regulation

reaches 0.25 percent to 0.5 percent of

Gross Domestic Product (GDP). In 1997,

real GDP was $7,188 billion so a rule

would have to cost at least $18 billion

to have a measurable effect. A regulation

with a smaller aggregate effect is

unlikely to have any measurable impact

unless it is highly focused on a

particular geographic region or

economic sector. The macro-economic

effects on the national economy from

the Stage 1 DBPR should be negligible

based on the fact that the total annual

costs are about $701 million per year (at

a 7 percent cost of capital) and the costs

are not expected to be highly focused on

a particular geographic region or sector.

e. Summary of EPA’s Consultation

with State, Local, and Tribal

Governments and Their Concerns.

Under UMRA section 202, EPA is to

provide a summary of its consultation

with elected representatives (or their

designated authorized employees) of

affected State, local and Tribal

governments in this rulemaking.

Although this rule was proposed before

UMRA became a statutory requirement,

EPA initiated consultations with

governmental entities and the private

sector affected by this rule through

various means. This included

participation on a Regulatory

Negotiation Committee chartered under

the Federal Advisory Committee Act

(FACA) in 1992–93 that included

stakeholders representing State and

local governments, public health

organizations, public water systems,

elected officials, consumer groups, and

environmental groups.

After the amendments to SDWA in

1996, the Agency initiated a second

FACA process, similarly involving a

broad range of stakeholders, and held

meetings during 1997 to address the

expedited deadline for promulgation of

the Stage 1 DBPR in November 1998.

EPA established the M–DBP Advisory

Committee to collect, share, and analyze

new data reviewed since the earlier Reg.

Neg. process and also to build a

consensus on the regulatory

implications of this new information.

The M–DBP Advisory Committee

established a technical working group to

assist them with the many scientific

issues surrounding this rule. The

Committee included representatives

from organizations such as the National

League of Cities, the National

Association of City and County Health

Officials, the Association of

Metropolitan Water Agencies, the

Association of State Drinking Water

Administrators, and the National

Association of Water Companies. In

addition, the Agency invited the Native

American Water Association to

participate in the FACA process to

develop this rule. Although they

eventually decided not to take part, the

Association continued to be informed of

meetings and developments through a

stakeholders mailing list.

Stakeholders who participated in the

FACA processes, as well as all other

interested members of the public, were

invited to comment on the proposed

rule and NODAs. Also, as part of the

Agency’s Communication Strategy, EPA

sent copies of the proposed rule and

NODAs to many stakeholders, including

six tribal associations.

In addition, the Agency notified

governmental entities and the private
69456 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

sector of opportunities to provide input

on this Stage 1 DBPR in the Federal

Register on July 29, 1994 (59 FR

38668—EPA, 1994A), November 3, 1997

(62 FR 59485—EPA, 1997b), and on

March 31, 1998 (63 FR 15974—EPA,

1998a). Additionally, EPA extended the

comment period for the March 31, 1998

NODA and announced a public meeting

to address new information. EPA

received approximately 213 written

comments on the July 29, 1994 notice,

approximately 57 written comments on

the November 3, 1997 notice, and

approximately 41 written comments on

the March 31, 1998 notice. Of the 213

comments received concerning the 1994

proposed rule, 11% were from States

and 41% were from local governments.

Also, one comment on the 1994

proposal was from a tribal group that

represented 43 tribes. Of the 57

comments received concerning the 1997

Notice of Data Availability, 18% were

from States and 37% were from local

governments. Of the 41 comments

received on the 1998 Notice of Data

Availability prior to the close of the

comment period, 5% were from States

and 15% were from local governments.

The public docket for this rulemaking

contains all comments received by the

Agency and provides details about the

nature of State, local, and tribal

government’s concerns. State and local

governments raised several concerns

including: the need for the Stage 1

DBPR; the high costs of the rule in

relation to the uncertain benefits; the

belief that not allowing predisinfection

credit would increase the microbial risk;

and the need for flexibility in

implementing the Stage 1 DPBR and

IESWTR to insure the rules are

implemented simultaneously. The one

tribal comment noted that compliance

would come at a cost of diverting funds

away from other important drinking

water needs such as maintaining

drinking water infrastructure.

EPA understands the State, local, and

tribal governments concerns with the

costs of the rule and the need to provide

additional public health protection for

the expenditure. The Agency believes

the final Stage 1 DPBR will provide

public health benefits to individuals by

reducing their exposures to DBPs, while

not requiring excessive capital

expenditures. As discussed above, the

majority of households will incur

additional costs of less than $1 per

month. As discussed in section III.E, the

final rule maintains the existing

predisinfection credit. Finally, in the

1997 DBP NODA (EPA, 1997b), EPA

requested comment on four alternative

schedules for complying with the Stage

1 DBPR. Most State and local

commenters preferred the option which

provides the maximum flexibility

allowed under the SDWA for systems to

comply with the Stage 1 DBPR, and this

is the option EPA selected for the final

rule.

f. Regulatory Alternatives Considered.

As required under Section 205 of the

UMRA, EPA considered several

regulatory alternatives developed by the

Reg Neg Committee and M–DBP

Advisory Committee and suggested by

stakeholders.

The Reg Neg Committee considered

several options including a proposed

TTHMs MCL of 80 μg/L and HAA5 MCL

of 60 μg/L for large systems (and a

simple standard of 100 μg/l for small

systems). Another option called for the

use of precursor removal technology to

reduce the level of total organic carbon

with alternative levels ranging from 4.0

to 0.5. Other options evaluated included

a 80 μg/L for TTHMs, 60 μg/L for HAA5,

and 4.0 for TOC. Finally, an option was

evaluated of a 80 μg/L for TTHMs, 60

μg/L for HAA5, and 5.0 for TOC. The

final consensus included a combination

of MCLs which would be equal for all

system size categories and a target TOC

level. Allowing small systems to comply

with a different MCL levels was rejected

because the rule would not adequately

protect the health of the population

served by these systems. A more

detailed description of these alternatives

is discussed in the document Unfunded

Mandates Reform Act Analysis for the

Stage 1 DBPR Rule which can be found

in the docket (EPA, 1998o).

Other regulatory alternatives were

considered by the M–DBP Advisory

Committee and these alternatives had

the overall effect of reducing the cost of

the final rule. For example, the M–DBP

Advisory Committee recommended

maintaining the predisinfection credit

after reviewing data which suggested

that many systems could probably meet

the proposed MCLs for DBPs while

maintaining current disinfection

practices. This decision was important

because systems would have had to

incur large capital costs to remain in

compliance with disinfection

requirements if predisinfection credits

were disallowed. Thus by allowing

predisinfection, the overall cost of the

rule was lowered.

Also, the Committee recommended

exempting systems for the enhanced

coagulation requirements based on their

raw water quality. For example, systems

with raw-water TOC of less than or

equal to 2.0 mg/L and raw-water SUVA

of less than or equal to 2.0 L/mg-m

would be exempt from the enhanced

coagulation requirements. This

exclusion was intended to promote costeffective enhanced coagulation (i.e.,

obtaining efficiencies of TOC removal

without excessive sludge production

and associated costs).

In conclusion, EPA believes that the

alternative selected for the Stage 1 DBPR

is the most cost-effective option that

achieves the objectives of the rule. For

a complete discussion of this issue see

EPA’s Regulatory Impact Analysis of the

Stage 1 Disinfectants/Disinfection

Byproducts Rule (EPA,1998g).

3. Impacts on Small Governments

The 1994 Stage 1 DBPR proposal was

done without the benefit of the UMRA

requirements. However, in preparation

for the final rule, EPA conducted

analysis on small government impacts

and included small government officials

or their designated representatives in

the rule making process. The FACA

processes gave a variety of stakeholders,

including small governments, the

opportunity for timely and meaningful

participation in the regulatory

development process. Representatives of

small government organizations were on

both the Reg. Neg. Committee and the

M–DBP Advisory Committee and their

representatives attended public

stakeholder meetings. Groups such as

the National Association of City and

County Health Officials and the

National League of Cities participated in

the rulemaking process. Through such

participation and exchange, EPA

notified potentially affected small

governments of requirements under

consideration and provided officials of

affected small governments with an

opportunity to have meaningful and

timely input into the development of

regulatory proposals.

In addition, EPA will educate, inform,

and advise small systems including

those run by small government about

DBPR requirements. One of the most

important components of this process is

the Small Entity Compliance Guide, as

required by the Small Business

Regulatory Enforcement Fairness Act of

1996. This plain-English guide will

explain what actions a small entity must

take to comply with the rule. Also, the

Agency is developing fact sheets that

concisely describe various aspects and

requirements of the DBPR.

D. National Technology Transfer and

Advancement Act

Under section 12(d) of the National

Technology Transfer and Advancement

Act (NTTAA), the Agency is required to

use voluntary consensus standards in its

regulatory activities unless to do so

would be inconsistent with applicable

law or otherwise impractical. Voluntary

consensus standards are technical
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69457

standards (e.g., materials specifications,

test methods, sampling procedures,

business practices, etc.) that are

developed or adopted by voluntary

consensus standards bodies. Where

available and potentially applicable

voluntary consensus standards are not

used by EPA, the Act requires the

Agency to provide Congress, through

OMB, an explanation of the reasons for

not using such standards.

EPA’s process for selecting the

analytical test methods is consistent

with section 12(d) of the NTTAA. EPA

performed literature searches to identify

analytical methods from industry,

academia, voluntary consensus

standards bodies, and other parties that

could be used to measure disinfectants,

DBPs, and other parameters. In addition,

EPA’s selection of the methods

benefited from the recommendations of

an Advisory Committee established

under the FACA Act to assist the

Agency with the Stage 1 DBPR. The

Committee made available additional

technical experts who were well-versed

in both existing analytical methods and

new developments in the field.

The results of these efforts form the

basis for the analytical methods in

today’s rule which includes: eight

methods for measuring different DBPs,

of which five are EPA methods and

three are voluntary consensus

standards; nine methods for measuring

disinfectants, all of which are voluntary

consensus standards; three voluntary

consensus methods for measuring TOC;

two EPA methods for measuring

bromide; one voluntary consensus

method for measuring UV254, and both

governmental and voluntary consensus

methods for measuring alkalinity.

Where applicable voluntary consensus

standards were not approved, this was

due to their inability to meet the data

quality objectives (e.g. accuracy,

sensitivity, quality control procedures)

necessary for demonstration of

compliance with the relevant

requirement.

In the 1997 NODA, EPA requested

comment on voluntary consensus

standards that had not been addressed

and which should be considered for

addition to the list of approved

analytical methods in the final rule. No

additional consensus methods were

suggested by commenters.

E. Executive Order 12866: Regulatory

Planning and Review

Under Executive Order 12866, (58 FR

41344—EPA, 1993c) the Agency must

determine whether the regulatory action

is ‘‘significant’’ and therefore subject to

OMB review and the requirements of

the Executive Order. The Order defines

‘‘significant regulatory action’’ as one

that is likely to result in a rule that may:

1. Have an annual effect on the

economy of $100 million or more or

adversely affect in a material way the

economy, a sector of the economy,

productivity, competition, jobs, the

environment, public health or safety, or

State, local, or tribal governments or

communities;

2. Create a serious inconsistency or

otherwise interfere with an action taken

or planned by another agency;

3. Materially alter the budgetary

impact of entitlement, grants, user fees,

or loan programs or the rights and

obligations of recipients thereof; or

4. Raise novel legal or policy issues

arising out of legal mandates, the

President’s priorities, or the principles

set forth in the Executive Order.

Pursuant to the terms of Executive

Order 12866, it has been determined

that this rule is a ‘‘significant regulatory

action’’ because it will have an annual

effect on the economy of $100 million

or more. As such, this action was

submitted to OMB for review. Changes

made in response to OMB suggestions or

recommendations are documented in

the public record.

F. Executive Order 12898:

Environmental Justice

Executive Order 12898 establishes a

Federal policy for incorporating

environmental justice into Federal

agency missions by directing agencies to

identify and address disproportionately

high and adverse human health or

environmental effects of its programs,

policies, and activities on minority and

low-income populations. The Agency

has considered environmental justice

related issues concerning the potential

impacts of this action and has consulted

with minority and low-income

stakeholders.

Two aspects of today’s rule comply

with the Environmental Justice

Executive Order which requires the

Agency to consider environmental

justice issues in the rulemaking and to

consult with Environmental Justice (EJ)

stakeholders. They can be classified as

follows: (1) the overall nature of the

rule, and (2) the convening of a

stakeholder meeting specifically to

address environmental justice issues.

The Stage 1 DBPR applies to community

water systems and nontransient

noncommunity water systems that treat

their water with a chemical disinfectant

for either primary or residual treatment.

Consequently, the health protection

benefits this rule provides are equal

across all income and minority groups

within these communities.

Finally, as part of EPA’s

responsibilities to comply with E.O.

12898, the Agency held a stakeholder

meeting on March 12, 1998 to address

various components of pending

drinking water regulations; and how

they may impact sensitive subpopulations, minority populations, and

low-income populations. Topics

discussed included treatment

techniques, costs and benefits, data

quality, health effects, and the

regulatory process. Participants

included national, state, tribal,

municipal, and individual stakeholders.

EPA conducted the meetings by video

conference call between eleven cities.

This meeting was a continuation of

stakeholder meetings that started in

1995 to obtain input on the Agency’s

Drinking Water Programs. The major

objectives for the March 12, 1998

meeting were:

• Solicit ideas from EJ stakeholders

on known issues concerning current

drinking water regulatory efforts;

• Identify key issues of concern to EJ

stakeholders; and

• Receive suggestions from EJ

stakeholders concerning ways to

increase representation of EJ

communities in OGWDW regulatory

efforts.

In addition, EPA developed a plainEnglish guide specifically for this

meeting to assist stakeholders in

understanding the multiple and

sometimes complex issues surrounding

drinking water regulation.

Overall, EPA believes this rule will

equally protect the health of all minority

and low-income populations served by

systems regulated under this rule from

exposure to DBPs.

G. Executive Order 13045: Protection of

Children From Environmental Health

Risks and Safety Risks

Executive Order 13045 applies to any

rule initiated after April 21, 1997, or

proposed after April 21, 1998, that (1) is

determined to be ‘‘economically

significant’’ as defined under E.O. 12866

and (2) concerns an environmental

health or safety risk that EPA has reason

to believe may have a disproportionate

effect on children. If the regulatory

action meets both criteria, the Agency

must evaluate the environmental health

or safety effects of the planned rule on

children, and explain why the planned

regulation is preferable to other

potentially effective and reasonably

feasible alternatives considered by the

Agency.

The final Stage 1 DBPR is not subject

to the Executive Order because EPA

published a notice of proposed

rulemaking before April 21, 1998.
69458 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

However, EPA’s policy since November

1, 1995, is to consistently and explicitly

consider risks to infants and children in

all risk assessments generated during its

decision making process including the

setting of standards to protect public

health and the environment.

EPA’s Office of Water has historically

considered risks to sensitive

populations (including fetuses, infants,

and children) in establishing drinking

water assessments, advisories or other

guidance, and standards (EPA, 1989c

and EPA, 1991). The disinfection of

public drinking water supplies to

prevent waterborne disease is the most

successful public health program in U.S.

history. However, numerous chemical

byproducts (DBPs) result from the

reaction of chlorine and other

disinfectants with naturally occurring

organic and inorganic material in source

water, and these may have potential

health risks. Thus, maximizing health

protection for sensitive subpopulations

requires balancing risks to achieve the

recognized benefits of controlling

waterborne pathogens while minimizing

risk of potential DBP toxicity. Human

experience shows that waterborne

disease from pathogens in drinking

water is a major concern for children

and other subgroups (elderly, immune

compromised, pregnant women)

because of their greater vulnerabilities

(Gerba et al., 1996). Based on animal

studies, there is also a concern for

potential risks posed by DBPs to

children and pregnant women (EPA,

1994a; EPA, 1998a).

In developing this regulation, risks to

sensitive subpopulations (including

fetuses and children) were taken into

account in the assessments of

disinfectants and disinfection

byproducts. A description of the data

available for evaluating risks to children

and the conclusions drawn can be found

in the public docket for this rulemaking

(EPA, 1998h). In addition, the Agency

has evaluated alternative regulatory

options and selected the option that will

provide the greatest benefits for all

people including children. See the

regulatory impact analysis for a

complete discussion of the different

options considered. It should also be

noted that the IESTWR, which

accompanies this final rule, provides

better controls of pathogens and

achieves the goal of increasing the

protection of children.

H. Consultations With the Science

Advisory Board, National Drinking

Water Advisory Council, and the

Secretary of Health and Human Services

In accordance with section 1412 (d)

and (e) of the Act, the Agency submitted

the proposed Stage 1 DBP rule to the

Science Advisory Board, National

Drinking Water Advisory Council

(NDWAC), and the Secretary of Health

and Human Services for their review.

EPA has evaluated comments received

from these organizations and considered

them in developing the final Stage 1

DBP rule.

I. Executive Order 12875: Enhancing the

Intergovernmental Partnership

Under Executive Order 12875, EPA

may not issue a regulation that is not

required by statute and that creates a

mandate upon a State, local or tribal

government, unless the Federal

government provides the funds

necessary to pay the direct compliance

costs incurred by those governments, or

EPA consults with those governments. If

EPA complies by consulting, Executive

Order 12875 requires EPA to provide to

the Office of Management and Budget a

description of the extent of EPA’s prior

consultation with representatives of

affected State, local and tribal

governments, the nature of their

concerns, copies of any written

communications from the governments,

and a statement supporting the need to

issue the regulation. In addition,

Executive Order 12875 requires EPA to

develop an effective process permitting

elected officials and other

representatives of State, local and tribal

governments ‘‘to provide meaningful

and timely input in the development of

regulatory proposals containing

significant unfunded mandates.’’

EPA has concluded that this rule will

create a mandate on State, local, and

tribal governments and that the Federal

government will not provide all of the

funds necessary to pay the direct costs

incurred by the State, local, and tribal

governments in complying with the

mandate. In developing this rule, EPA

consulted with State and local

governments to enable them to provide

meaningful and timely input in the

development of this rule. EPA also

invited the Native American Water

Association to participate in the FACA

process to develop this rule, but they

decided not to take part in the

deliberations.

As described in Section V.C.2.e, EPA

held extensive meetings with a variety

of State and local representatives, who

provided meaningful and timely input

in the development of the proposed

rule. State and local representatives

were also part of the FACA committees

involved in the development of this

rule. Summaries of the meetings have

been included in the public docket for

this rulemaking. See section V.C.2.e for

summaries of the extent of EPA’s

consultation with State, local, and tribal

governments; the nature of the

government concerns; and EPA’s

position supporting the need to issue

this rule.

J. Executive Order 13084: Consultation

and Coordination With Indian Tribal

Governments

Under Executive Order 13084, EPA

may not issue a regulation that is not

required by statute, that significantly or

uniquely affects the communities of

Indian tribal governments, and that

imposes substantial direct compliance

costs on those communities, unless the

Federal government provides the funds

necessary to pay the direct compliance

costs incurred by the tribal

governments, or EPA consults with

those governments. If EPA complies by

consulting, Executive Order 13084

requires EPA to provide to the Office of

Management and Budget, in a separately

identified section of the preamble to the

rule, a description of the extent of EPA’s

prior consultation with representatives

of affected tribal governments, a

summary of the nature of their concerns,

and a statement supporting the need to

issue the regulation. In addition,

Executive Order 13084 requires EPA to

develop an effective process permitting

elected officials and other

representatives of Indian tribal

governments ‘‘to provide meaningful

and timely input in the development of

regulatory policies on matters that

significantly or uniquely affect their

communities.’’

EPA has concluded that this rule will

significantly affect communities of

Indian tribal governments. It will also

impose substantial direct compliance

costs on such communities, and the

Federal government will not provide all

the funds necessary to pay the direct

costs incurred by the tribal governments

in complying with the rule. In

developing this rule, EPA consulted

with representatives of tribal

governments pursuant to both Executive

Order 12875 and Executive Order

13084. EPA’s consultation, the nature of

the governments’ concerns, and EPA’s

position supporting the need for this

rule are discussed above in the

preamble section that addresses

compliance with Executive Order

12875. Specifically in developing this

rule, the Agency invited the Native

American Water Association to

participate in the FACA process to

develop this rule. Although they

eventually decided not to take part, the

Association continued to be informed of

meetings and developments through a

stakeholders mailing list. As described

in Section V.C.2.e of the discussion on
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69459

UMRA, EPA held extensive meetings

that provided the opportunity for

meaningful and timely input in the

development of the proposed rule.

Summaries of the meetings have been

included in the public docket for this

rulemaking.

K. Submission to Congress and the

General Accounting Office

The Congressional Review Act, 5

U.S.C. 801 et seq., as added by the Small

Business Regulatory Enforcement

Fairness Act of 1996, generally provides

that before a rule may take effect, the

agency promulgating the rule must

submit a rule report, which includes a

copy of the rule, to each House of the

Congress and to the Comptroller General

of the United States. EPA will submit a

report containing this rule and other

required information to the U.S. Senate,

the U.S. House of Representatives, and

the Comptroller General of the United

States prior to publication of the rule in

the Federal Register. A major rule

cannot take effect until 60 days after it

is published in the Federal Register.

This rule is a ‘‘major rule’’ as defined by

5 U.S.C. 804(2). This rule will be

effective February 16, 1999.

L. Likely Effect of Compliance With the

Stage 1 DBPR on the Technical,

Financial, and Managerial Capacity of

Public Water Systems

Section 1420(d)(3) of the SDWA as

amended requires that, in promulgating

a NPDWR, the Administrator shall

include an analysis of the likely effect

of compliance with the regulation on

the technical, financial, and managerial

capacity of public water systems. The

following analysis has been performed

to fulfill this statutory obligation.

Overall water system capacity is

defined in EPA guidance (EPA 816–R–

98–006) as the ability to plan for,

achieve, and maintain compliance with

applicable drinking water standards.

Capacity has three components:

technical, managerial, and financial.

Technical capacity is the physical and

operational ability of a water system to

meet SDWA requirements. Technical

capacity refers to the physical

infrastructure of the water system,

including the adequacy of source water

and the adequacy of treatment, storage,

and distribution infrastructure. It also

refers to the ability of system personnel

to adequately operate and maintain the

system and to otherwise implement

requisite technical knowledge. A water

system’s technical capacity can be

determined by examining key issues

and questions, including:

• Source water adequacy. Does the

system have a reliable source of

drinking water? Is the source of

generally good quality and adequately

protected?

• Infrastructure adequacy. Can the

system provide water that meets SDWA

standards? What is the condition of its

infrastructure, including well(s) or

source water intakes, treatment, storage,

and distribution? What is the

infrastructure’s life expectancy? Does

the system have a capital improvement

plan?

• Technical knowledge and

implementation. Is the system’s operator

certified? Does the operator have

sufficient technical knowledge of

applicable standards? Can the operator

effectively implement this technical

knowledge? Does the operator

understand the system’s technical and

operational characteristics? Does the

system have an effective operation and

maintenance program?

Managerial capacity is the ability of a

water system to conduct its affairs in a

manner enabling the system to achieve

and maintain compliance with SDWA

requirements. Managerial capacity refers

to the system’s institutional and

administrative capabilities.

Managerial capacity can be assessed

through key issues and questions,

including:

• Ownership accountability. Are the

system owner(s) clearly identified? Can

they be held accountable for the system?

• Staffing and organization. Are the

system operator(s) and manager(s)

clearly identified? Is the system

properly organized and staffed? Do

personnel understand the management

aspects of regulatory requirements and

system operations? Do they have

adequate expertise to manage water

system operations? Do personnel have

the necessary licenses and

certifications?

• Effective external linkages. Does the

system interact well with customers,

regulators, and other entities? Is the

system aware of available external

resources, such as technical and

financial assistance?

Financial capacity is a water system’s

ability to acquire and manage sufficient

financial resources to allow the system

to achieve and maintain compliance

with SDWA requirements.

Financial capacity can be assessed

through key issues and questions,

including:

• Revenue sufficiency. Do revenues

cover costs? Are water rates and charges

adequate to cover the cost of water?

• Credit worthiness. Is the system

financially healthy? Does it have access

to capital through public or private

sources?

• Fiscal management and controls.

Are adequate books and records

maintained? Are appropriate budgeting,

accounting, and financial planning

methods used? Does the system manage

its revenues effectively?

There are 76,051 systems affected by

this rule. Of these, 12,998 will have to

modify their treatment process and

undertake disinfectant and DBP

monitoring and reporting. Some of this

smaller group may also be required to

do DBP precursor monitoring and

reporting. The other 63,063 systems will

need to do disinfectant and DBP

monitoring and reporting, but will not

need to modify their treatment process.

Some of this larger group may also be

required to do DBP precursor

monitoring and reporting.

Systems not modifying treatment are

not generally expected to require

significantly increased technical,

financial, or managerial capacity to

comply with these new requirements.

Certainly some individual facilities may

have weaknesses in one or more of these

areas but overall, systems should have

or be able to obtain the capacity needed

for these activities.

Systems needing to modify treatment

will employ one or more of a variety of

steps. The steps expected to be

employed by 50% or more of subpart H

systems and by eight percent or more of

ground water systems covered by the

rule include a combination of low cost

alternatives, including switching to

chloramines for residual disinfection,

moving the point of disinfectant

application, and improving precursor

removal. EPA estimates that less than

seven percent of systems in any category

will resort to higher cost alternatives,

such as switching to ozone or

chloramines for primary disinfection or

using GAC or membranes for precursor

removal. These higher cost alternatives

may also provide other treatment

benefits, so the cost may be somewhat

offset by eliminating the need for

technologies to remove other

contaminants. Some of these systems

may choose nontreatment alternatives

such as consolidation with another

system or changing to a higher quality

water source.

Furthermore, there are a number of

actions that are expected to be taken

disproportionately by smaller sized

systems (that is to say, a greater

percentage of smaller sized systems will

undertake than will larger sized

systems). These steps include increased

plant staffing and additional staff

training to understand process control

strategy. Small systems will be required

to do this since larger systems have

already undertaken these changes to
69460 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

some extent for compliance with the

1979 TTHM rule.

For many systems serving less than

10,000 persons which need to make

treatment modifications, an

enhancement of technical, financial,

and managerial capacity may likely be

needed. As the preceding paragraph

makes clear, these systems will be

making structural improvements and

enhancing laboratory and staff capacity.

Larger sized systems have typically

already made these improvements as

part of normal operations. Meeting the

requirements of the Stage 1 DBPR will

require operating at a higher level of

sophistication and in a better state of

repair than some plants serving less

than 10,000 people have considered

acceptable in the past.

Certainly there will be exceptions in

systems serving both below 10,000

persons and above. Some larger plants

will doubtless find their technical,

managerial, and financial capacity taxed

by the new requirements. Likewise,

some plants serving less than 10,000

persons will already have more than

adequate technical, financial, and

managerial capacity to meet these

requirements. However, in general, the

systems serving less than 10,000

persons needing to make treatment

modifications will be the ones most

needing to enhance their capacity.

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Compliance. AWWA, 89:5:64.

115. Xie, Yuefeng. 1995. Effects of Sodium

Chloride on DBP Analytical Results,

Extended Abstract, Division of

Environmental Chemistry, American

Chemical Society Annual Conference,

Chicago, IL, Aug. 21–26, 1995.

List of Subjects

40 CFR Part 9

Environmental protection, Reporting

and recordkeeping requirements.

40 CFR Parts 141 and 142

Analytical methods, Drinking water,

Environmental protection, Incorporation

by reference, Intergovernmental

relations, Public utilities, Reporting and

recordkeeping requirements, Utilities,

Water supply.

Dated: November 30, 1998.

Carol M. Browner,

Administrator.

For the reasons set out in the

preamble, title 40, chapter I of the Code

of Federal Regulations is amended as

follows:

PART 9—[AMENDED]

1. The authority citation for part 9

continues to read as follows:

Authority: 7 U.S.C. 135 et seq., 136–136y;

15 U.S.C. 2001, 2003, 2005, 2006, 2601–2671;

21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33

U.S.C. 1251 et seq., 1311, 1313d, 1314, 1318,

1321, 1326, 1330, 1342, 1344, 1345 (d) and

(e), 1361; E.O. 11735, 38 FR 21243, 3 CFR,

1971–1975 Comp. p. 973; 42 U.S.C. 241,

242b, 243, 246, 300f, 300g, 300g–1, 300g–2,

300g–3, 300g–4, 300g–5, 300g–6, 300j–1,

300j–2, 300j–3, 300j–4, 300j–9, 1857 et seq.,

6901–6992k, 7401–7671q, 7542, 9601–9657,

11023, 11048.

2. In § 9.1 the table is amended by

adding under the indicated heading: the

new entries in numerical order to read

as follows:

§ 9.1 OMB approvals under the Paperwork

Reduction Act.

* * * * *

40 CFR citation OMB control No.

* * * * *

National Primary Drinking

Water Regulations

* * * * *

141.130–141.132 ...................... 2040–0204

141.134–141.135 ...................... 2040–0204

* * * * *

PART 141—NATIONAL PRIMARY

DRINKING WATER REGULATIONS

3. The authority citation for part 141

continues to read as follows:

Authority: 42 U.S.C. 300f, 300g–1, 300g–2,

300g–3, 300g–4, 300g–5, 300g–6, 300j–4,

300j–9, and 300j–11.

4. Section 141.2 is amended by

adding the following definitions in

alphabetical order to read as follows:

§ 141.2 Definitions.

* * * * *

Enhanced coagulation means the

addition of sufficient coagulant for

improved removal of disinfection

byproduct precursors by conventional

filtration treatment.

* * * * *

Enhanced softening means the

improved removal of disinfection

byproduct precursors by precipitative

softening.

* * * * *

GAC10 means granular activated

carbon filter beds with an empty-bed

contact time of 10 minutes based on

average daily flow and a carbon

reactivation frequency of every 180

days.

* * * * *

Haloacetic acids (five) (HAA5) mean

the sum of the concentrations in

milligrams per liter of the haloacetic

acid compounds (monochloroacetic

acid, dichloroacetic acid, trichloroacetic

acid, monobromoacetic acid, and

dibromoacetic acid), rounded to two

significant figures after addition.

* * * * *

Maximum residual disinfectant level

(MRDL) means a level of a disinfectant

added for water treatment that may not

be exceeded at the consumer’s tap

without an unacceptable possibility of

adverse health effects. For chlorine and

chloramines, a PWS is in compliance

with the MRDL when the running

annual average of monthly averages of

samples taken in the distribution

system, computed quarterly, is less than

or equal to the MRDL. For chlorine

dioxide, a PWS is in compliance with

the MRDL when daily samples are taken

at the entrance to the distribution

system and no two consecutive daily

samples exceed the MRDL. MRDLs are

enforceable in the same manner as

maximum contaminant levels under

Section 1412 of the Safe Drinking Water

Act. There is convincing evidence that

addition of a disinfectant is necessary

for control of waterborne microbial

contaminants. Notwithstanding the

MRDLs listed in § 141.65, operators may

increase residual disinfectant levels of

chlorine or chloramines (but not

chlorine dioxide) in the distribution

system to a level and for a time

necessary to protect public health to

address specific microbiological

contamination problems caused by

circumstances such as distribution line

breaks, storm runoff events, source

water contamination, or crossconnections.

* * * * *

Maximum residual disinfectant level

goal (MRDLG) means the maximum

level of a disinfectant added for water

treatment at which no known or

anticipated adverse effect on the health

of persons would occur, and which

allows an adequate margin of safety.

MRDLGs are nonenforceable health

goals and do not reflect the benefit of

the addition of the chemical for control

of waterborne microbial contaminants.

* * * * *

Subpart H systems means public

water systems using surface water or

ground water under the direct influence

of surface water as a source that are

subject to the requirements of subpart H

of this part.

* * * * *

SUVA means Specific Ultraviolet

Absorption at 254 nanometers (nm), an

indicator of the humic content of water.

It is a calculated parameter obtained by

dividing a sample’s ultraviolet

absorption at a wavelength of 254 nm

(UV 254) (in m =1) by its concentration of

dissolved organic carbon (DOC) (in mg/

L).

* * * * *

Total Organic Carbon (TOC) means

total organic carbon in mg/L measured

using heat, oxygen, ultraviolet

irradiation, chemical oxidants, or

combinations of these oxidants that

convert organic carbon to carbon

dioxide, rounded to two significant

figures.

* * * * *

5. Section 141.12 is revised to read as

follows:

§ 141.12 Maximum contaminant levels for

total trihalomethanes.

The maximum contaminant level of

0.10 mg/L for total trihalomethanes (the

sum of the concentrations of

bromodichloromethane,

dibromochloromethane,

tribromomethane (bromoform), and

trichloromethane (chloroform)) applies

to subpart H community water systems

which serve a population of 10,000

people or more until December 16,

2001. This level applies to community

water systems that use only ground

water not under the direct influence of

surface water and serve a population of

10,000 people or more until December
69464 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

16, 2003. Compliance with the

maximum contaminant level for total

trihalomethanes is calculated pursuant

to § 141.30. After December 16, 2003,

this section is no longer applicable.

6. Section 141.30 is amended by

revising the the first sentences in

paragraphs (d) and (f) and adding

paragraph (h) to read as follows:

§ 141.30 Total trihalomethanes sampling,

analytical and other requirements.

* * * * *

(d) Compliance with § 141.12 shall be

determined based on a running annual

average of quarterly samples collected

by the system as prescribed in

paragraph (b)(1) or (2) of this

section. * * *

* * * * *

(f) Before a community water system

makes any significant modifications to

its existing treatment process for the

purposes of achieving compliance with

§ 141.12, such system must submit and

obtain State approval of a detailed plan

setting forth its proposed modification

and those safeguards that it will

implement to ensure that the

bacteriological quality of the drinking

water served by such system will not be

adversely affected by such

modification. * * *

* * * * *

(h) The requirements in paragraphs (a)

through (g) of this section apply to

subpart H community water systems

which serve a population of 10,000 or

more until December 16, 2001. The

requirements in paragraphs (a) through

(g) of this section apply to community

water systems which use only ground

water not under the direct influence of

surface water that add a disinfectant

(oxidant) in any part of the treatment

process and serve a population of

10,000 or more until December 16, 2003.

After December 16, 2003, this section is

no longer applicable.

7. Section 141.32 is amended by

revising the heading in paragraph (a)

introductory text, the first sentence of

paragraph (a)(1)(iii) introductory text,

and the first sentence of paragraph (c),

and adding paragraphs (a)(1)(iii)(E) and

(e) (76) through (81), to read as follows:

§ 141.32 Public notification.

* * * * *

(a) Maximum contaminant levels

(MCLs), maximum residual disinfectant

levels (MRDLs). * * *

(1) * * *

(iii) For violations of the MCLs of

contaminants or MRDLs of disinfectants

that may pose an acute risk to human

health, by furnishing a copy of the

notice to the radio and television

stations serving the area served by the

public water system as soon as possible

but in no case later than 72 hours after

the violation. ***

* * * * *

(E) Violation of the MRDL for chlorine

dioxide as defined in § 141.65 and

determined according to § 141.133(c)(2).

* * * * *

(c) * * * The owner or operator of a

community water system must give a

copy of the most recent public notice for

any outstanding violation of any

maximum contaminant level, or any

maximum residual disinfectant level, or

any treatment technique requirement, or

any variance or exemption schedule to

all new billing units or new hookups

prior to or at the time service begins.

* * * * *

(e) * * *

(76) Chlorine. The United States

Environmental Protection Agency (EPA)

sets drinking water standards and has

determined that chlorine is a health

concern at certain levels of exposure.

Chlorine is added to drinking water as

a disinfectant to kill bacteria and other

disease-causing microorganisms and is

also added to provide continuous

disinfection throughout the distribution

system. Disinfection is required for

surface water systems. However, at high

doses for extended periods of time,

chlorine has been shown to affect blood

and the liver in laboratory animals. EPA

has set a drinking water standard for

chlorine to protect against the risk of

these adverse effects. Drinking water

which meets this EPA standard is

associated with little to none of this risk

and should be considered safe with

respect to chlorine.

(77) Chloramines. The United States

Environmental Protection Agency (EPA)

sets drinking water standards and has

determined that chloramines are a

health concern at certain levels of

exposure. Chloramines are added to

drinking water as a disinfectant to kill

bacteria and other disease-causing

microorganisms and are also added to

provide continuous disinfection

throughout the distribution system.

Disinfection is required for surface

water systems. However, at high doses

for extended periods of time,

chloramines have been shown to affect

blood and the liver in laboratory

animals. EPA has set a drinking water

standard for chloramines to protect

against the risk of these adverse effects.

Drinking water which meets this EPA

standard is associated with little to none

of this risk and should be considered

safe with respect to chloramines.

(78) Chlorine dioxide. The United

States Environmental Protection Agency

(EPA) sets drinking water standards and

has determined that chlorine dioxide is

a health concern at certain levels of

exposure. Chlorine dioxide is used in

water treatment to kill bacteria and

other disease-causing microorganisms

and can be used to control tastes and

odors. Disinfection is required for

surface water systems. However, at high

doses, chlorine dioxide-treated drinking

water has been shown to affect blood in

laboratory animals. Also, high levels of

chlorine dioxide given to laboratory

animals in drinking water have been

shown to cause neurological effects on

the developing nervous system. These

neurodevelopmental effects may occur

as a result of a short-term excessive

chlorine dioxide exposure. To protect

against such potentially harmful

exposures, EPA requires chlorine

dioxide monitoring at the treatment

plant, where disinfection occurs, and at

representative points in the distribution

system serving water users. EPA has set

a drinking water standard for chlorine

dioxide to protect against the risk of

these adverse effects.

Note: In addition to the language in this

introductory text of paragraph (e)(78),

systems must include either the language in

paragraph (e)(78)(i) or (e)(78)(ii) of this

section. Systems with a violation at the

treatment plant, but not in the distribution

system, are required to use the language in

paragraph (e)(78)(i) of this section and treat

the violation as a nonacute violation.

Systems with a violation in the distribution

system are required to use the language in

paragraph (e)(78)(ii) of this section and treat

the violation as an acute violation.

(i) The chlorine dioxide violations

reported today are the result of

exceedances at the treatment facility

only, and do not include violations

within the distribution system serving

users of this water supply. Continued

compliance with chlorine dioxide levels

within the distribution system

minimizes the potential risk of these

violations to present consumers.

(ii) The chlorine dioxide violations

reported today include exceedances of

the EPA standard within the

distribution system serving water users.

Violations of the chlorine dioxide

standard within the distribution system

may harm human health based on shortterm exposures. Certain groups,

including pregnant women, infants, and

young children, may be especially

susceptible to adverse effects of

excessive exposure to chlorine dioxidetreated water. The purpose of this notice

is to advise that such persons should

consider reducing their risk of adverse

effects from these chlorine dioxide

violations by seeking alternate sources

of water for human consumption until

such exceedances are rectified. Local
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69465

and State health authorities are the best

sources for information concerning

alternate drinking water.

(79) Disinfection byproducts and

treatment technique for DBPs. The

United States Environmental Protection

Agency (EPA) sets drinking water

standards and requires the disinfection

of drinking water. However, when used

in the treatment of drinking water,

disinfectants react with naturallyoccurring organic and inorganic matter

present in water to form chemicals

called disinfection byproducts (DBPs).

EPA has determined that a number of

DBPs are a health concern at certain

levels of exposure. Certain DBPs,

including some trihalomethanes (THMs)

and some haloacetic acids (HAAs), have

been shown to cause cancer in

laboratory animals. Other DBPs have

been shown to affect the liver and the

nervous system, and cause reproductive

or developmental effects in laboratory

animals. Exposure to certain DBPs may

produce similar effects in people. EPA

has set standards to limit exposure to

THMs, HAAs, and other DBPs.

(80) Bromate. The United States

Environmental Protection Agency (EPA)

sets drinking water standards and has

determined that bromate is a health

concern at certain levels of exposure.

Bromate is formed as a byproduct of

ozone disinfection of drinking water.

Ozone reacts with naturally occurring

bromide in the water to form bromate.

Bromate has been shown to produce

cancer in rats. EPA has set a drinking

water standard to limit exposure to

bromate.

(81) Chlorite. The United States

Environmental Protection Agency (EPA)

sets drinking water standards and has

determined that chlorite is a health

concern at certain levels of exposure.

Chlorite is formed from the breakdown

of chlorine dioxide, a drinking water

disinfectant. Chlorite in drinking water

has been shown to affect blood and the

developing nervous system. EPA has set

a drinking water standard for chlorite to

protect against these effects. Drinking

water which meets this standard is

associated with little to none of these

risks and should be considered safe

with respect to chlorite.

* * * * *

8. Subpart F is amended by revising

the subpart heading and adding

§§ 141.53 and 141.54 to read as follows:

Subpart F—Maximum Contaminant

Level Goals and Maximum Residual

Disinfectant Level Goals

* * * * *

§ 141.53—Maximum contaminant level goals

for disinfection byproducts.

MCLGs for the following disinfection

byproducts are as indicated:

Disinfection byproduct MCLG

(mg/L)

Chloroform ...................................... Zero

Bromodichloromethane ................... Zero

Bromoform ...................................... Zero

Bromate .......................................... Zero

Dichloroacetic acid .......................... Zero

Trichloroacetic acid ......................... 0.3

Chlorite ............................................ 0.8

Dibromochloromethane ................... 0.06

§ 141.54 Maximum residual disinfectant

level goals for disinfectants.

MRDLGs for disinfectants are as

follows:

Disinfectant residual MRDLG(mg/L)

Chlorine ............................... 4 (as Cl 2).

Chloramines ......................... 4 (as Cl 2).

Chlorine dioxide ................... 0.8 (as ClO2)

9. Subpart G is amended by revising

the subpart heading and adding

§§ 141.64 and 141.65 to read as follows:

Subpart G—National Revised Primary

Drinking Water Regulations: Maximum

Contaminant Levels and Maximum

Residual Disinfectant Levels

* * * * *

§ 141.64 Maximum contaminant levels for

disinfection byproducts.

(a) The maximum contaminant levels

(MCLs) for disinfection byproducts are

as follows:

Disinfection byproduct MCL

(mg/L)

Total trihalomethanes (TTHM) ........ 0.080

Haloacetic acids (five) (HAA5) ....... 0.060

Bromate .......................................... 0.010

Chlorite ............................................ 1.0

(b) Compliance dates. (1) CWSs and

NTNCWSs. Subpart H systems serving

10,000 or more persons must comply

with this section beginning December

16, 2001. Subpart H systems serving

fewer than 10,000 persons and systems

using only ground water not under the

direct influence of surface water must

comply with this section beginning

December 16, 2003.

(2) A system that is installing GAC or

membrane technology to comply with

this section may apply to the State for

an extension of up to 24 months past the

dates in paragraphs (b)(1) of this section,

but not beyond December 16, 2003. In

granting the extension, States must set

a schedule for compliance and may

specify any interim measures that the

system must take. Failure to meet the

schedule or interim treatment

requirements constitutes a violation of a

National Primary Drinking Water

Regulation.

(c) The Administrator, pursuant to

Section 1412 of the Act, hereby

identifies the following as the best

technology, treatment techniques, or

other means available for achieving

compliance with the maximum

contaminant levels for disinfection

byproducts identified in paragraph (a) of

this section:

Disinfection byproduct

Best available technology

TTHM ... Enhanced coagulation or enhanced softening or GAC10,

with chlorine as the primary and

residual disinfectant

HAA5 .... Enhanced coagulation or enhanced softening or GAC10,

with chlorine as the primary and

residual disinfectant.

Bromate Control of ozone treatment process to reduce production of bromate.

Chlorite Control of treatment processes to

reduce disinfectant demand and

control of disinfection treatment

processes to reduce disinfectant

levels.

§ 141.65 Maximum residual disinfectant

levels.

(a) Maximum residual disinfectant

levels (MRDLs) are as follows:

Disinfectant residual MRDL (mg/L)

Chlorine ............................... 4.0 (as Cl2).

Chloramines ......................... 4.0 (as Cl2).

Chlorine dioxide ................... 0.8 (as ClO2).

(b) Compliance dates.

(1) CWSs and NTNCWSs. Subpart H

systems serving 10,000 or more persons

must comply with this section

beginning December 16, 2001. Subpart

H systems serving fewer than 10,000

persons and systems using only ground

water not under the direct influence of

surface water must comply with this

subpart beginning December 16, 2003.

(2) Transient NCWSs. Subpart H

systems serving 10,000 or more persons

and using chlorine dioxide as a

disinfectant or oxidant must comply

with the chlorine dioxide MRDL

beginning December 16, 2001. Subpart

H systems serving fewer than 10,000

persons and using chlorine dioxide as a

disinfectant or oxidant and systems

using only ground water not under the

direct influence of surface water and

using chlorine dioxide as a disinfectant

or oxidant must comply with the
69466 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

chlorine dioxide MRDL beginning

December 16, 2003.

(c) The Administrator, pursuant to

Section 1412 of the Act, hereby

identifies the following as the best

technology, treatment techniques, or

other means available for achieving

compliance with the maximum residual

disinfectant levels identified in

paragraph (a) of this section: control of

treatment processes to reduce

disinfectant demand and control of

disinfection treatment processes to

reduce disinfectant levels.

10. A new subpart L is added to read

as follows:

Subpart L—Disinfectant Residuals,

Disinfection Byproducts, and

Disinfection Byproduct Precursors

Sec.

141.130 General requirements.

141.131 Analytical requirements.

141.132 Monitoring requirements.

141.133 Compliance requirements.

141.134 Reporting and recordkeeping

requirements.

141.135 Treatment technique for control of

disinfection byproduct (DBP) precursors.

§ 141.130 General requirements.

(a) The requirements of this subpart L

constitute national primary drinking

water regulations.

(1) The regulations in this subpart

establish criteria under which

community water systems (CWSs) and

nontransient, noncommunity water

systems (NTNCWSs) which add a

chemical disinfectant to the water in

any part of the drinking water treatment

process must modify their practices to

meet MCLs and MRDLs in §§ 141.64 and

141.65, respectively, and must meet the

treatment technique requirements for

disinfection byproduct precursors in

§ 141.135.

(2) The regulations in this subpart

establish criteria under which transient

NCWSs that use chlorine dioxide as a

disinfectant or oxidant must modify

their practices to meet the MRDL for

chlorine dioxide in § 141.65.

(3) EPA has established MCLs for

TTHM and HAA5 and treatment

technique requirements for disinfection

byproduct precursors to limit the levels

of known and unknown disinfection

byproducts which may have adverse

health effects. These disinfection

byproducts may include chloroform;

bromodichloromethane;

dibromochloromethane; bromoform;

dichloroacetic acid; and trichloroacetic

acid.

(b) Compliance dates. (1) CWSs and

NTNCWSs. Unless otherwise noted,

systems must comply with the

requirements of this subpart as follows.

Subpart H systems serving 10,000 or

more persons must comply with this

subpart beginning December 16, 2001.

Subpart H systems serving fewer than

10,000 persons and systems using only

ground water not under the direct

influence of surface water must comply

with this subpart beginning December

16, 2003.

(2) Transient NCWSs. Subpart H

systems serving 10,000 or more persons

and using chlorine dioxide as a

disinfectant or oxidant must comply

with any requirements for chlorine

dioxide and chlorite in this subpart

beginning December 16, 2001. Subpart

H systems serving fewer than 10,000

persons and using chlorine dioxide as a

disinfectant or oxidant and systems

using only ground water not under the

direct influence of surface water and

using chlorine dioxide as a disinfectant

or oxidant must comply with any

requirements for chlorine dioxide and

chlorite in this subpart beginning

December 16, 2003.

(c) Each CWS and NTNCWS regulated

under paragraph (a) of this section must

be operated by qualified personnel who

meet the requirements specified by the

State and are included in a State register

of qualified operators.

(d) Control of disinfectant residuals.

Notwithstanding the MRDLs in § 141.65,

systems may increase residual

disinfectant levels in the distribution

system of chlorine or chloramines (but

not chlorine dioxide) to a level and for

a time necessary to protect public

health, to address specific

microbiological contamination problems

caused by circumstances such as, but

not limited to, distribution line breaks,

storm run-off events, source water

contamination events, or crossconnection events.

§ 141.131 Analytical requirements.

(a) General. (1) Systems must use only

the analytical method(s) specified in

this section, or otherwise approved by

EPA for monitoring under this subpart,

to demonstrate compliance with the

requirements of this subpart. These

methods are effective for compliance

monitoring February 16, 1999.

(2) The following documents are

incorporated by reference. The Director

of the Federal Register approves this

incorporation by reference in

accordance with 5 U.S.C. 552(a) and 1

CFR part 51. Copies may be inspected

at EPA’s Drinking Water Docket, 401 M

Street, SW, Washington, DC 20460, or at

the Office of the Federal Register, 800

North Capitol Street, NW, Suite 700,

Washington DC. EPA Method 552.1 is in

Methods for the Determination of

Organic Compounds in Drinking WaterSupplement II, USEPA, August 1992,

EPA/600/R–92/129 (available through

National Information Technical Service

(NTIS), PB92–207703). EPA Methods

502.2, 524.2, 551.1, and 552.2 are in

Methods for the Determination of

Organic Compounds in Drinking WaterSupplement III, USEPA, August 1995,

EPA/600/R–95/131. (available through

NTIS, PB95–261616). EPA Method

300.0 is in Methods for the

Determination of Inorganic Substances

in Environmental Samples, USEPA,

August 1993, EPA/600/R–93/100.

(available through NTIS, PB94–121811).

EPA Method 300.1 is titled USEPA

Method 300.1, Determination of

Inorganic Anions in Drinking Water by

Ion Chromatography, Revision 1.0,

USEPA, 1997, EPA/600/R–98/118

(available through NTIS, PB98-169196);

also available from: Chemical Exposure

Research Branch, Microbiological &

Chemical Exposure Assessment

Research Division, National Exposure

Research Laboratory, U.S.

Environmental Protection Agency,

Cincinnati, OH 45268, Fax Number:

513–569–7757, Phone number: 513–

569–7586. Standard Methods 4500-Cl D,

4500-Cl E, 4500-Cl F, 4500-Cl G, 4500-

Cl H, 4500-Cl I, 4500-ClO2 D, 4500-ClO2

E, 6251 B, and 5910 B shall be followed

in accordance with Standard Methods

for the Examination of Water and

Wastewater, 19th Edition, American

Public Health Association, 1995; copies

may be obtained from the American

Public Health Association, 1015

Fifteenth Street, NW, Washington, DC

20005. Standard Methods 5310 B, 5310

C, and 5310 D shall be followed in

accordance with the Supplement to the

19th Edition of Standard Methods for

the Examination of Water and

Wastewater, American Public Health

Association, 1996; copies may be

obtained from the American Public

Health Association, 1015 Fifteenth

Street, NW, Washington, DC 20005.

ASTM Method D 1253–86 shall be

followed in accordance with the Annual

Book of ASTM Standards, Volume

11.01, American Society for Testing and

Materials, 1996 edition; copies may be

obtained from the American Society for

Testing and Materials, 100 Barr Harbor

Drive, West Conshohoken, PA 19428.

(b) Disinfection byproducts. (1)

Systems must measure disinfection

byproducts by the methods (as modified

by the footnotes) listed in the following

table:
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69467

APPROVED METHODS FOR DISINFECTION BYPRODUCT COMPLIANCE MONITORING

Methodology 2 EPA method Standard method

Byproduct measured 1

TTHM HAA5 Chlorite 4 Bromate

P&T/GC/ElCD & PID ......................................... 3502.2 X

P&T/GC/MS ...................................................... 524.2 X

LLE/GC/ECD ..................................................... 551.1 X

LLE/GC/ECD ..................................................... 6251 B X

SPE/GC/ECD .................................................... 552.1 X

LLE/GC/ECD ..................................................... 552.2 X

Amperometric Titration ...................................... 4500-ClO2 E X

IC ....................................................................... 300.0 X

IC ....................................................................... 300.1 X X

1X indicates method is approved for measuring specified disinfection byproduct.

2P&T = purge and trap; GC = gas chromatography; ElCD = electrolytic conductivity detector; PID = photoionization detector; MS= mass spectrometer; LLE= liquid/liquid extraction; ECD = electron capture detector; SPE= solid phase extractor; IC = ion chromatography. 3 If TTHMs are the only analytes being measured in the sample, then a PID is not required.

4Amperometric titration may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as prescribed in

§ 141.132(b)(2)(i)(A). Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the distribution system, as prescribed in § 141.132(b)(2)(i)(B) and (b)(2)(ii).

(2) Analysis under this section for

disinfection byproducts must be

conducted by laboratories that have

received certification by EPA or the

State. To receive certification to conduct

analyses for the contaminants in

§ 141.64(a), the laboratory must carry

out annual analyses of performance

evaluation (PE) samples approved by

EPA or the State. In these analyses of PE

samples, the laboratory must achieve

quantitative results within the

acceptance limit on a minimum of 80%

of the analytes included in each PE

sample. The acceptance limit is defined

as the 95% confidence interval

calculated around the mean of the PE

study data between a maximum and

minimum acceptance limit of +/¥50%

and +/¥15% of the study mean.

(c) Disinfectant residuals. (1) Systems

must measure residual disinfectant

concentrations for free chlorine,

combined chlorine (chloramines), and

chlorine dioxide by the methods listed

in the following table:

APPROVED METHODS FOR DISINFECTANT RESIDUAL COMPLIANCE MONITORING

Methodology Standard

method ASTM method

Residual Measured 1

Free

chlorine

Combined

chlorine

Total

chlorine

Chlorine

dioxide

Amperometric Titration ........................................ 4500-Cl D D 1253–86 X X X

Low Level Amperometric Titration ...................... 4500-Cl E X

DPD Ferrous Titrimetric ...................................... 4500-Cl F X X X

DPD Colorimetric ................................................ 4500-Cl G X X X

Syringaldazin e (FACTS) .................................... 4500-Cl H X

Iodometric Electrode ........................................... 4500-Cl I X

DPD ..................................................................... 4500-ClO2 D X

Amperometric Method II ..................................... 4500-ClO2 E X

1X indicates method is approved for measuring specified disinfectant residual.

(2) If approved by the State, systems

may also measure residual disinfectant

concentrations for chlorine,

chloramines, and chlorine dioxide by

using DPD colorimetric test kits.

(3) A party approved by EPA or the

State must measure residual disinfectant

concentration.

(d) Additional analytical methods.

Systems required to analyze parameters

not included in paragraphs (b) and (c)

of this section must use the following

methods. A party approved by EPA or

the State must measure these

parameters.

(1) Alkalinity. All methods allowed in

§ 141.89(a) for measuring alkalinity.

(2) Bromide. EPA Method 300.0 or

EPA Method 300.1.

(3) Total Organic Carbon (TOC).

Standard Method 5310 B (HighTemperature Combustion Method) or

Standard Method 5310 C (PersulfateUltraviolet or Heated-Persulfate

Oxidation Method) or Standard Method

5310 D (Wet-Oxidation Method). TOC

samples may not be filtered prior to

analysis. TOC samples must either be

analyzed or must be acidified to achieve

pH less than 2.0 by minimal addition of

phosphoric or sulfuric acid as soon as

practical after sampling, not to exceed

24 hours. Acidified TOC samples must

be analyzed within 28 days.

(4) Specific Ultraviolet Absorbance

(SUVA). SUVA is equal to the UV

absorption at 254nm (UV254) (measured

in m-1 divided by the dissolved organic

carbon (DOC) concentration (measured

as mg/L). In order to determine SUVA,

it is necessary to separately measure

UV254 and DOC. When determining

SUVA, systems must use the methods

stipulated in paragraph (d)(4)(i) of this

section to measure DOC and the method

stipulated in paragraph (d)(4)(ii) of this

section to measure UV254. SUVA must

be determined on water prior to the

addition of disinfectants/oxidants by the

system. DOC and UV254 samples used to

determine a SUVA value must be taken

at the same time and at the same

location.

(i) Dissolved Organic Carbon (DOC).

Standard Method 5310 B (HighTemperature Combustion Method) or

Standard Method 5310 C (PersulfateUltraviolet or Heated-Persulfate

Oxidation Method) or Standard Method
69468 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

5310 D (Wet-Oxidation Method). Prior

to analysis, DOC samples must be

filtered through a 0.45 μm pore-diameter

filter. Water passed through the filter

prior to filtration of the sample must

serve as the filtered blank. This filtered

blank must be analyzed using

procedures identical to those used for

analysis of the samples and must meet

the following criteria: DOC < 0.5 mg/L.

DOC samples must be filtered through

the 0.45 μm pore-diameter filter prior to

acidification. DOC samples must either

be analyzed or must be acidified to

achieve pH less than 2.0 by minimal

addition of phosphoric or sulfuric acid

as soon as practical after sampling, not

to exceed 48 hours. Acidified DOC

samples must be analyzed within 28

days.

(ii) Ultraviolet Absorption at 254 nm

(UV254). Method 5910 B (Ultraviolet

Absorption Method). UV absorption

must be measured at 253.7 nm (may be

rounded off to 254 nm). Prior to

analysis, UV254 samples must be filtered

through a 0.45 μm pore-diameter filter.

The pH of UV254 samples may not be

adjusted. Samples must be analyzed as

soon as practical after sampling, not to

exceed 48 hours.

(5) pH. All methods allowed in

§ 141.23(k)(1) for measuring pH.

§ 141.132 Monitoring requirements.

(a) General requirements. (1) Systems

must take all samples during normal

operating conditions.

(2) Systems may consider multiple

wells drawing water from a single

aquifer as one treatment plant for

determining the minimum number of

TTHM and HAA5 samples required,

with State approval in accordance with

criteria developed under § 142.16(f)(5)

of this chapter.

(3) Failure to monitor in accordance

with the monitoring plan required

under paragraph (f) of this section is a

monitoring violation.

(4) Failure to monitor will be treated

as a violation for the entire period

covered by the annual average where

compliance is based on a running

annual average of monthly or quarterly

samples or averages and the system’s

failure to monitor makes it impossible to

determine compliance with MCLs or

MRDLs.

(5) Systems may use only data

collected under the provisions of this

subpart or subpart M of this part to

qualify for reduced monitoring.

(b) Monitoring requirements for

disinfection byproducts. (1) TTHMs and

HAA5. (i) Routine monitoring. Systems

must monitor at the frequency indicated

in the following table:

ROUTINE MONITORING FREQUENCY FOR TTHM AND HAA5

Type of system Minimum monitoring frequency Sample location in the distribution system

Subpart H system serving at least

10,000 persons.

Four water samples per quarter

per treatment plant.

At least 25 percent of all samples collected each quarter at locations

representing maximum residence time. Remaining samples taken at

locations representative of at least average residence time in the

distribution system and representing the entire distribution system,

taking into account number of persons served, different sources of

water, and different treatment methods.1

Subpart H system serving from

500 to 9,999 persons.

One water sample per quarter per

treatment plant.

Locations representing maximum residence time.1

Subpart H system serving fewer

than 500 persons.

One sample per year per treatment plant during month of

warmest water temperature.

Locations representing maximum residence time.1 If the sample (or

average of annual samples, if more than one sample is taken) exceeds MCL, system must increase monitoring to one sample per

treatment plant per quarter, taken at a point reflecting the maximum

residence time in the distribution system, until system meets reduced monitoring criteria in paragraph (c) of this section.

System using only ground water

not under direct influence of surface water using chemical disinfectant and serving at least

10,000 persons.

One water sample per quarter per

treatment plant 2.

Locations representing maximum residence time.1

System using only ground water

not under direct influence of surface water using chemical disinfectant and serving fewer than

10,000 persons.

One sample per year per treatment plant 2 during month of

warmest water temperature.

Locations representing maximum residence time.1 If the sample (or

average of annual samples, if more than one sample is taken) exceeds MCL, system must increase monitoring to one sample per

treatment plant per quarter, taken at a point reflecting the maximum

residence time in the distribution system, until system meets criteria

in paragraph (c) of this section for reduced monitoring.

1 If a system elects to sample more frequently than the minimum required, at least 25 percent of all samples collected each quarter (including

those taken in excess of the required frequency) must be taken at locations that represent the maximum residence time of the water in the distribution system. The remaining samples must be taken at locations representative of at least average residence time in the distribution system. 2 Multiple wells drawing water from a single aquifer may be considered one treatment plant for determining the minimum number of samples

required, with State approval in accordance with criteria developed under § 142.16(f)(5) of this chapter.

(ii) Systems may reduce monitoring,

except as otherwise provided, in

accordance with the following table:
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69469

Reduced Monitoring Frequency for TTHM and HAA5

If you are a . . .

You may reduce monitoring if you

have monitored at least one year

and your . . .

To this level

Subpart H system serving at least

10,000 persons which has a

source water annual average

TOC level, before any treatment,

≤4.0 mg/L.

TTHM annual average ≤0.040 mg/

L and HAA5 annual average

≤0.030 mg/L.

One sample per treatment plant per quarter at distribution system location reflecting maximum residence time.

Subpart H system serving from

500 to 9,999 persons which has

a source water annual average

TOC level, before any treatment,

≤4.0 mg/L.

TTHM annual average ≤0.040 mg/

L and HAA5 annual average

≤0.030 mg/L.

One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest

water temperature. NOTE: Any Subpart H system serving fewer

than 500 persons may not reduce its monitoring to less than one

sample per treatment plant per year.

System using only ground water

not under direct influence of surface water using chemical disinfectant and serving at least

10,000 persons.

TTHM annual average ≤0.040 mg/

L and HAA5 annual average

≤0.030 mg/L.

One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest

water temperature

System using only ground water

not under direct influence of surface water using chemical disinfectant and serving fewer than

10,000 persons.

TTHM annual average ≤0.040 mg/

L and HAA5 annual average

≤0.030 mg/L for two consecutive

years OR TTHM annual average

≤0.020 mg/L and HAA5 annual

average ≤0.015 mg/L for one

year.

One sample per treatment plant per three year monitoring cycle at

distribution system location reflecting maximum residence time during month of warmest water temperature, with the three-year cycle

beginning on January 1 following quarter in which system qualifies

for reduced monitoring.

(iii) Systems on a reduced monitoring

schedule may remain on that reduced

schedule as long as the average of all

samples taken in the year (for systems

which must monitor quarterly) or the

result of the sample (for systems which

must monitor no more frequently than

annually) is no more than 0.060 mg/L

and 0.045 mg/L for TTHMs and HAA5,

respectively. Systems that do not meet

these levels must resume monitoring at

the frequency identified in paragraph

(b)(1)(i) of this section in the quarter

immediately following the quarter in

which the system exceeds 0.060 mg/L

and 0.045 mg/L for TTHMs and HAA5,

respectively.

(iv) The State may return a system to

routine monitoring at the State’s

discretion.

(2) Chlorite. Community and

nontransient noncommunity water

systems using chlorine dioxide, for

disinfection or oxidation, must conduct

monitoring for chlorite.

(i) Routine monitoring. (A) Daily

monitoring. Systems must take daily

samples at the entrance to the

distribution system. For any daily

sample that exceeds the chlorite MCL,

the system must take additional samples

in the distribution system the following

day at the locations required by

paragraph (b)(2)(ii) of this section, in

addition to the sample required at the

entrance to the distribution system.

(B) Monthly monitoring. Systems must

take a three-sample set each month in

the distribution system. The system

must take one sample at each of the

following locations: near the first

customer, at a location representative of

average residence time, and at a location

reflecting maximum residence time in

the distribution system. Any additional

routine sampling must be conducted in

the same manner (as three-sample sets,

at the specified locations). The system

may use the results of additional

monitoring conducted under paragraph

(b)(2)(ii) of this section to meet the

requirement for monitoring in this

paragraph.

(ii) Additional monitoring. On each

day following a routine sample

monitoring result that exceeds the

chlorite MCL at the entrance to the

distribution system, the system is

required to take three chlorite

distribution system samples at the

following locations: as close to the first

customer as possible, in a location

representative of average residence time,

and as close to the end of the

distribution system as possible

(reflecting maximum residence time in

the distribution system).

(iii) Reduced monitoring. (A) Chlorite

monitoring at the entrance to the

distribution system required by

paragraph (b)(2)(i)(A) of this section

may not be reduced.

(B) Chlorite monitoring in the

distribution system required by

paragraph (b)(2)(i)(B) of this section may

be reduced to one three-sample set per

quarter after one year of monitoring

where no individual chlorite sample

taken in the distribution system under

paragraph (b)(2)(i)(B) of this section has

exceeded the chlorite MCL and the

system has not been required to conduct

monitoring under paragraph (b)(2)(ii) of

this section. The system may remain on

the reduced monitoring schedule until

either any of the three individual

chlorite samples taken quarterly in the

distribution system under paragraph

(b)(2)(i)(B) of this section exceeds the

chlorite MCL or the system is required

to conduct monitoring under paragraph

(b)(2)(ii) of this section, at which time

the system must revert to routine

monitoring.

(3) Bromate. (i) Routine monitoring.

Community and nontransient

noncommunity systems using ozone, for

disinfection or oxidation, must take one

sample per month for each treatment

plant in the system using ozone.

Systems must take samples monthly at

the entrance to the distribution system

while the ozonation system is operating

under normal conditions.

(ii) Reduced monitoring. Systems

required to analyze for bromate may

reduce monitoring from monthly to

once per quarter, if the system

demonstrates that the average source

water bromide concentration is less than

0.05 mg/L based upon representative

monthly bromide measurements for one

year. The system may remain on

reduced bromate monitoring until the

running annual average source water

bromide concentration, computed

quarterly, is equal to or greater than 0.05

mg/L based upon representative

monthly measurements. If the running

annual average source water bromide

concentration is ≥0.05 mg/L, the system

must resume routine monitoring
69470 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

required by paragraph (b)(3)(i) of this

section.

(c) Monitoring requirements for

disinfectant residuals. (1) Chlorine and

chloramines. (i) Routine monitoring.

Systems must measure the residual

disinfectant level at the same points in

the distribution system and at the same

time as total coliforms are sampled, as

specified in § 141.21. Subpart H systems

may use the results of residual

disinfectant concentration sampling

conducted under § 141.74(b)(6)(i) for

unfiltered systems or § 141.74(c)(3)(i) for

systems which filter, in lieu of taking

separate samples.

(ii) Reduced monitoring. Monitoring

may not be reduced.

(2) Chlorine dioxide. (i) Routine

monitoring. Community, nontransient

noncommunity, and transient

noncommunity water systems that use

chlorine dioxide for disinfection or

oxidation must take daily samples at the

entrance to the distribution system. For

any daily sample that exceeds the

MRDL, the system must take samples in

the distribution system the following

day at the locations required by

paragraph (c)(2)(ii) of this section, in

addition to the sample required at the

entrance to the distribution system.

(ii) Additional monitoring. On each

day following a routine sample

monitoring result that exceeds the

MRDL, the system is required to take

three chlorine dioxide distribution

system samples. If chlorine dioxide or

chloramines are used to maintain a

disinfectant residual in the distribution

system, or if chlorine is used to

maintain a disinfectant residual in the

distribution system and there are no

disinfection addition points after the

entrance to the distribution system (i.e.,

no booster chlorination), the system

must take three samples as close to the

first customer as possible, at intervals of

at least six hours. If chlorine is used to

maintain a disinfectant residual in the

distribution system and there are one or

more disinfection addition points after

the entrance to the distribution system

(i.e., booster chlorination), the system

must take one sample at each of the

following locations: as close to the first

customer as possible, in a location

representative of average residence time,

and as close to the end of the

distribution system as possible

(reflecting maximum residence time in

the distribution system).

(iii) Reduced monitoring. Chlorine

dioxide monitoring may not be reduced.

(d) Monitoring requirements for

disinfection byproduct precursors

(DBPP). (1) Routine monitoring. Subpart

H systems which use conventional

filtration treatment (as defined in

§ 141.2) must monitor each treatment

plant for TOC no later than the point of

combined filter effluent turbidity

monitoring and representative of the

treated water. All systems required to

monitor under this paragraph (d)(1)

must also monitor for TOC in the source

water prior to any treatment at the same

time as monitoring for TOC in the

treated water. These samples (source

water and treated water) are referred to

as paired samples. At the same time as

the source water sample is taken, all

systems must monitor for alkalinity in

the source water prior to any treatment.

Systems must take one paired sample

and one source water alkalinity sample

per month per plant at a time

representative of normal operating

conditions and influent water quality.

(2) Reduced monitoring. Subpart H

systems with an average treated water

TOC of less than 2.0 mg/L for two

consecutive years, or less than 1.0 mg/

L for one year, may reduce monitoring

for both TOC and alkalinity to one

paired sample and one source water

alkalinity sample per plant per quarter.

The system must revert to routine

monitoring in the month following the

quarter when the annual average treated

water TOC ≥2.0 mg/L.

(e) Bromide. Systems required to

analyze for bromate may reduce bromate

monitoring from monthly to once per

quarter, if the system demonstrates that

the average source water bromide

concentration is less than 0.05 mg/L

based upon representative monthly

measurements for one year. The system

must continue bromide monitoring to

remain on reduced bromate monitoring.

(f) Monitoring plans. Each system

required to monitor under this subpart

must develop and implement a

monitoring plan. The system must

maintain the plan and make it available

for inspection by the State and the

general public no later than 30 days

following the applicable compliance

dates in § 141.130(b). All Subpart H

systems serving more than 3300 people

must submit a copy of the monitoring

plan to the State no later than the date

of the first report required under

§ 141.134. The State may also require

the plan to be submitted by any other

system. After review, the State may

require changes in any plan elements.

The plan must include at least the

following elements.

(1) Specific locations and schedules

for collecting samples for any

parameters included in this subpart.

(2) How the system will calculate

compliance with MCLs, MRDLs, and

treatment techniques.

(3) If approved for monitoring as a

consecutive system, or if providing

water to a consecutive system, under the

provisions of § 141.29, the sampling

plan must reflect the entire distribution

system.

§ 141.133 Compliance requirements.

(a) General requirements. (1) Where

compliance is based on a running

annual average of monthly or quarterly

samples or averages and the system’s

failure to monitor for TTHM, HAA5, or

bromate, this failure to monitor will be

treated as a monitoring violation for the

entire period covered by the annual

average. Where compliance is based on

a running annual average of monthly or

quarterly samples or averages and the

system’s failure to monitor makes it

impossible to determine compliance

with MRDLs for chlorine and

chloramines, this failure to monitor will

be treated as a monitoring violation for

the entire period covered by the annual

average.

(2) All samples taken and analyzed

under the provisions of this subpart

must be included in determining

compliance, even if that number is

greater than the minimum required.

(3) If, during the first year of

monitoring under § 141.132, any

individual quarter’s average will cause

the running annual average of that

system to exceed the MCL, the system

is out of compliance at the end of that

quarter.

(b) Disinfection byproducts. (1)

TTHMs and HAA5. (i) For systems

monitoring quarterly, compliance with

MCLs in § 141.64 must be based on a

running annual arithmetic average,

computed quarterly, of quarterly

arithmetic averages of all samples

collected by the system as prescribed by

§ 141.132(b)(1). If the running annual

arithmetic average of quarterly averages

covering any consecutive four-quarter

period exceeds the MCL, the system is

in violation of the MCL and must notify

the public pursuant to § 141.32, in

addition to reporting to the State

pursuant to § 141.134. If a PWS fails to

complete four consecutive quarters’

monitoring, compliance with the MCL

for the last four-quarter compliance

period must be based on an average of

the available data.

(ii) For systems monitoring less

frequently than quarterly, compliance

must be based on an average of samples

taken that year under the provisions of

§ 141.132(b)(1). If the average of these

samples exceeds the MCL, the system

must increase monitoring to once per

quarter per treatment plant.

(iii) Systems on a reduced monitoring

schedule whose annual average exceeds

the MCL will revert to routine

monitoring immediately. These systems
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69471

will not be considered in violation of

the MCL until they have completed one

year of routine monitoring.

(2). Bromate. Compliance must be

based on a running annual arithmetic

average, computed quarterly, of monthly

samples (or, for months in which the

system takes more than one sample, the

average of all samples taken during the

month) collected by the system as

prescribed by § 141.132(b)(3). If the

average of samples covering any

consecutive four-quarter period exceeds

the MCL, the system is in violation of

the MCL and must notify the public

pursuant to § 141.32, in addition to

reporting to the State pursuant to

§ 141.134. If a PWS fails to complete 12

consecutive months’ monitoring,

compliance with the MCL for the last

four-quarter compliance period must be

based on an average of the available

data.

(3) Chlorite. Compliance must be

based on an arithmetic average of each

three sample set taken in the

distribution system as prescribed by

§ 141.132(b)(2)(i)(B) and

§ 141.132(b)(2)(ii). If the arithmetic

average of any three sample set exceeds

the MCL, the system is in violation of

the MCL and must notify the public

pursuant to § 141.32, in addition to

reporting to the State pursuant to

§ 141.134.

(c) Disinfectant residuals. (1) Chlorine

and chloramines. (i) Compliance must

be based on a running annual arithmetic

average, computed quarterly, of monthly

averages of all samples collected by the

system under § 141.132(c)(1). If the

average of quarterly averages covering

any consecutive four-quarter period

exceeds the MRDL, the system is in

violation of the MRDL and must notify

the public pursuant to § 141.32, in

addition to reporting to the State

pursuant to § 141.134.

(ii) In cases where systems switch

between the use of chlorine and

chloramines for residual disinfection

during the year, compliance must be

determined by including together all

monitoring results of both chlorine and

chloramines in calculating compliance.

Reports submitted pursuant to § 141.134

must clearly indicate which residual

disinfectant was analyzed for each

sample.

(2) Chlorine dioxide. (i) Acute

violations. Compliance must be based

on consecutive daily samples collected

by the system under § 141.132(c)(2). If

any daily sample taken at the entrance

to the distribution system exceeds the

MRDL, and on the following day one (or

more) of the three samples taken in the

distribution system exceed the MRDL,

the system is in violation of the MRDL

and must take immediate corrective

action to lower the level of chlorine

dioxide below the MRDL and must

notify the public pursuant to the

procedures for acute health risks in

§ 141.32(a)(1)(iii)(E). Failure to take

samples in the distribution system the

day following an exceedance of the

chlorine dioxide MRDL at the entrance

to the distribution system will also be

considered an MRDL violation and the

system must notify the public of the

violation in accordance with the

provisions for acute violations under

§ 141.32(a)(1)(iii)(E).

(ii) Nonacute violations. Compliance

must be based on consecutive daily

samples collected by the system under

§ 141.132(c)(2). If any two consecutive

daily samples taken at the entrance to

the distribution system exceed the

MRDL and all distribution system

samples taken are below the MRDL, the

system is in violation of the MRDL and

must take corrective action to lower the

level of chlorine dioxide below the

MRDL at the point of sampling and will

notify the public pursuant to the

procedures for nonacute health risks in

§ 141.32(e)(78). Failure to monitor at the

entrance to the distribution system the

day following an exceedance of the

chlorine dioxide MRDL at the entrance

to the distribution system is also an

MRDL violation and the system must

notify the public of the violation in

accordance with the provisions for

nonacute violations under

§ 141.32(e)(78).

(d) Disinfection byproduct precursors

(DBPP). Compliance must be

determined as specified by § 141.135(b).

Systems may begin monitoring to

determine whether Step 1 TOC

removals can be met 12 months prior to

the compliance date for the system. This

monitoring is not required and failure to

monitor during this period is not a

violation. However, any system that

does not monitor during this period,

and then determines in the first 12

months after the compliance date that it

is not able to meet the Step 1

requirements in § 141.135(b)(2) and

must therefore apply for alternate

minimum TOC removal (Step 2)

requirements, is not eligible for

retroactive approval of alternate

minimum TOC removal (Step 2)

requirements as allowed pursuant to

§ 141.135(b)(3) and is in violation.

Systems may apply for alternate

minimum TOC removal (Step 2)

requirements any time after the

compliance date.

§ 141.134 Reporting and recordkeeping

requirements.

(a) Systems required to sample

quarterly or more frequently must report

to the State within 10 days after the end

of each quarter in which samples were

collected, notwithstanding the

provisions of § 141.31. Systems required

to sample less frequently than quarterly

must report to the State within 10 days

after the end of each monitoring period

in which samples were collected.

(b) Disinfection byproducts. Systems

must report the information specified in

the following table:

If you are a... You must report...1

System monitoring for TTHM and HAA5 under the requirements of

§§ 141.132(b) on a quarterly or more frequent basis.

(1) The number of samples taken during the last quarter.

(2) The location, date, and result of each sample taken during the last

quarter.

(3) The arithmetic average of all samples taken in the last quarter.

(4) The annual arithmetic average of the quarterly arithmetic averages

of this section for the last four quarters.

(5) Whether the MCL was exceeded.

System monitoring for TTHMs and HAA5 under the requirements of

§§ 141.132(b) less frequently than quarterly (but at least annually).

(1) The number of samples taken during the last year.

(2) The location, date, and result of each sample taken during the last

quarter.

(3) The arithmetic average of all samples taken over the last year.

(4) Whether the MCL was exceeded.

System monitoring for TTHMs and HAA5 under the requirements of

§ 141.132(b) less frequently than annually.

(1) The location, date, and result of the last sample taken.

(2) Whether the MCL was exceeded.
69472 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

If you are a... You must report...1

System monitoring for chlorite under the requirements of § 141.132(b) .. (1) The number of samples taken each month for the last 3 months.

(2) The location, date, and result of each sample taken during the last

quarter.

(3) For each month in the reporting period, the arithmetic average of all

samples taken in the month.

(4) Whether the MCL was exceeded, and in which month it was exceeded.

System monitoring for bromate under the requirements of § 141.132(b) (1) The number of samples taken during the last quarter.

(2) The location, date, and result of each sample taken during the last

quarter.

(3) The arithmetic average of the monthly arithmetic averages of all

samples taken in the last year.

(4) Whether the MCL was exceeded.

(c) Disinfectants. Systems must report

the information specified in the

following table:

If you are a... You must report...1

System monitoring for chlorine or chloramines under the requirements

of § 141.132(c).

(1) The number of samples taken during each month of the last quarter.

(2) The monthly arithmetic average of all samples taken in each month

for the last 12 months.

(3) The arithmetic average of all monthly averages for the last 12

months.

(4) Whether the MRDL was exceeded.

System monitoring for chlorine dioxide under the requirements of

§ 141.132(c).

(1) The dates, results, and locations of samples taken during the last

quarter.

(2) Whether the MRDL was exceeded.

(3) Whether the MRDL was exceeded in any two consecutive daily

samples and whether the resulting violation was acute or nonacute.

1The State may choose to perform calculations and determine whether the MRDL was exceeded, in lieu of having the system report that information.

(d) Disinfection byproduct precursors

and enhanced coagulation or enhanced

softening. Systems must report the

information specified in the following

table:

If you are a . . . You must report . . .1

System monitoring monthly or quarterly for TOC under the requirements of § 141.132(d) and required to meet the enhanced coagulation or enhanced softening requirements in § 141.135(b)(2) or (3).(1) The number of paired (source water and treated water, prior to continuous disinfection) samples taken during the last quarter.

(2) The location, date, and result of each paired sample and associated alkalinity taken during the last quarter.

(3) For each month in the reporting period that paired samples were

taken, the arithmetic average of the percent reduction of TOC for

each paired sample and the required TOC percent removal.

(4) Calculations for determining compliance with the TOC percent removal requirements, as provided in § 141.135(c)(1).

(5) Whether the system is in compliance with the enhanced coagulation or enhanced softening percent removal requirements in

§ 141.135(b) for the last four quarters.

System monitoring monthly or quarterly for TOC under the requirements of § 141.132(d) and meeting one or more of the alternative

compliance criteria in § 141.135(a)(2) or (3).

(1) The alternative compliance criterion that the system is using.

(2) The number of paired samples taken during the last quarter.

(3) The location, date, and result of each paired sample and associated alkalinity taken during the last quarter.

(4) The running annual arithmetic average based on monthly averages

(or quarterly samples) of source water TOC for systems meeting a

criterion in §§ 141.135(a)(2)(i) or (iii) or of treated water TOC for systems meeting the criterion in § 141.135(a)(2)(ii).
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69473

If you are a . . . You must report . . .1

(5) The running annual arithmetic average based on monthly averages

(or quarterly samples) of source water SUVA for systems meeting

the criterion in § 141.135(a)(2)(v) or of treated water SUVA for systems meeting the criterion in § 141.135(a)(2)(vi).

(6) The running annual average of source water alkalinity for systems

meeting the criterion in § 141.135(a)(2)(iii) and of treated water alkalinity for systems meeting the criterion in § 141.135(a)(3)(i).

(7) The running annual average for both TTHM and HAA5 for systems

meeting the criterion in § 141.135(a)(2)(iii) or (iv).

(8) The running annual average of the amount of magnesium hardness

removal (as CaCO3, in mg/L) for systems meeting the criterion in

§ 141.135(a)(3)(ii).

(9) Whether the system is in compliance with the particular alternative

compliance criterion in § 141.135(a)(2) or (3).

1The State may choose to perform calculations and determine whether the treatment technique was met, in lieu of having the system report

that information.

§ 141.135 Treatment technique for control

of disinfection byproduct (DBP) precursors.

(a) Applicability. (1) Subpart H

systems using conventional filtration

treatment (as defined in § 141.2 ) must

operate with enhanced coagulation or

enhanced softening to achieve the TOC

percent removal levels specified in

paragraph (b) of this section unless the

system meets at least one of the

alternative compliance criteria listed in

paragraph (a)(2) or (a)(3) of this section.

(2) Alternative compliance criteria for

enhanced coagulation and enhanced

softening systems. Subpart H systems

using conventional filtration treatment

may use the alternative compliance

criteria in paragraphs (a)(2)(i) through

(vi) of this section to comply with this

section in lieu of complying with

paragraph (b) of this section. Systems

must still comply with monitoring

requirements in § 141.132(d).

(i) The system’s source water TOC

level, measured according to

§ 141.131(d)(3), is less than 2.0 mg/L,

calculated quarterly as a running annual

average.

(ii) The system’s treated water TOC

level, measured according to

§ 141.131(d)(3), is less than 2.0 mg/L,

calculated quarterly as a running annual

average.

(iii) The system’s source water TOC

level, measured as required by

§ 141.131(d)(3), is less than 4.0 mg/L,

calculated quarterly as a running annual

average; the source water alkalinity,

measured according to § 141.131(d)(1),

is greater than 60 mg/L (as CaCO3),

calculated quarterly as a running annual

average; and either the TTHM and

HAA5 running annual averages are no

greater than 0.040 mg/L and 0.030 mg/

L, respectively; or prior to the effective

date for compliance in § 141.130(b), the

system has made a clear and irrevocable

financial commitment not later than the

effective date for compliance in

§ 141.130(b) to use of technologies that

will limit the levels of TTHMs and

HAA5 to no more than 0.040 mg/L and

0.030 mg/L, respectively. Systems must

submit evidence of a clear and

irrevocable financial commitment, in

addition to a schedule containing

milestones and periodic progress reports

for installation and operation of

appropriate technologies, to the State for

approval not later than the effective date

for compliance in § 141.130(b). These

technologies must be installed and

operating not later than June 16, 2005.

Failure to install and operate these

technologies by the date in the approved

schedule will constitute a violation of

National Primary Drinking Water

Regulations.

(iv) The TTHM and HAA5 running

annual averages are no greater than

0.040 mg/L and 0.030 mg/L,

respectively, and the system uses only

chlorine for primary disinfection and

maintenance of a residual in the

distribution system.

(v) The system’s source water SUVA,

prior to any treatment and measured

monthly according to § 141.131(d)(4), is

less than or equal to 2.0 L/mg-m,

calculated quarterly as a running annual

average.

(vi) The system’s finished water

SUVA, measured monthly according to

§ 141.131(d)(4), is less than or equal to

2.0 L/mg-m, calculated quarterly as a

running annual average.

(3) Additional alternative compliance

criteria for softening systems. Systems

practicing enhanced softening that

cannot achieve the TOC removals

required by paragraph (b)(2) of this

section may use the alternative

compliance criteria in paragraphs

(a)(3)(i) and (ii) of this section in lieu of

complying with paragraph (b) of this

section. Systems must still comply with

monitoring requirements in

§ 141.132(d).

(i) Softening that results in lowering

the treated water alkalinity to less than

60 mg/L (as CaCO3), measured monthly

according to § 141.131(d)(1) and

calculated quarterly as a running annual

average.

(ii) Softening that results in removing

at least 10 mg/L of magnesium hardness

(as CaCO3), measured monthly and

calculated quarterly as an annual

running average.

(b) Enhanced coagulation and

enhanced softening performance

requirements. (1) Systems must achieve

the percent reduction of TOC specified

in paragraph (b)(2) of this section

between the source water and the

combined filter effluent, unless the State

approves a system’s request for alternate

minimum TOC removal (Step 2)

requirements under paragraph (b)(3) of

this section.

(2) Required Step 1 TOC reductions,

indicated in the following table, are

based upon specified source water

parameters measured in accordance

with § 141.131(d). Systems practicing

softening are required to meet the Step

1 TOC reductions in the far-right

column (Source water alkalinity >120

mg/L) for the specified source water

TOC:
69474 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

STEP 1 REQUIRED REMOVAL OF TOC BY ENHANCED COAGULATION AND ENHANCED SOFTENING FOR SUBPART H

SYSTEMS USING CONVENTIONAL TREATMENT 1, 2

Source-water TOC, mg/L

Source-water alkalinity, mg/L as CaCO3

0–60 (percent) ≤60–120 (percent)

>120 3 (percent)

>2.0–4.0 ....................................................................................................................................... 35.0 25.0 15.0

>4.0–8.0 ....................................................................................................................................... 45.0 35.0 25.0

>8.0 .............................................................................................................................................. 50.0 40.0 30.0

1Systems meeting at least one of the conditions in paragraph (a)(2)(i)–(vi) of this section are not required to operate with enhanced coagulation. 2Softening systems meeting one of the alternative compliance criteria in paragraph (a)(3) of this section are not required to operate with enhanced softening. 3Systems practicing softening must meet the TOC removal requirements in this column.

(3) Subpart H conventional treatment

systems that cannot achieve the Step 1

TOC removals required by paragraph

(b)(2) of this section due to water quality

parameters or operational constraints

must apply to the State, within three

months of failure to achieve the TOC

removals required by paragraph (b)(2) of

this section, for approval of alternative

minimum TOC (Step 2) removal

requirements submitted by the system.

If the State approves the alternative

minimum TOC removal (Step 2)

requirements, the State may make those

requirements retroactive for the

purposes of determining compliance.

Until the State approves the alternate

minimum TOC removal (Step 2)

requirements, the system must meet the

Step 1 TOC removals contained in

paragraph (b)(2) of this section.

(4) Alternate minimum TOC removal

(Step 2) requirements. Applications

made to the State by enhanced

coagulation systems for approval of

alternative minimum TOC removal

(Step 2) requirements under paragraph

(b)(3) of this section must include, as a

minimum, results of bench- or pilotscale testing conducted under paragraph

(b)(4)(i) of this section and used to

determine the alternate enhanced

coagulation level.

(i) Alternate enhanced coagulation

level is defined as coagulation at a

coagulant dose and pH as determined by

the method described in paragraphs

(b)(4)(i) through (v) of this section such

that an incremental addition of 10 mg/

L of alum (as aluminum) (or equivalent

amount of ferric salt) results in a TOC

removal of ≤ 0.3 mg/L. The percent

removal of TOC at this point on the

‘‘TOC removal versus coagulant dose’’

curve is then defined as the minimum

TOC removal required for the system.

Once approved by the State, this

minimum requirement supersedes the

minimum TOC removal required by the

table in paragraph (b)(2) of this section.

This requirement will be effective until

such time as the State approves a new

value based on the results of a new

bench- and pilot-scale test. Failure to

achieve State-set alternative minimum

TOC removal levels is a violation of

National Primary Drinking Water

Regulations.

(ii) Bench- or pilot-scale testing of

enhanced coagulation must be

conducted by using representative water

samples and adding 10 mg/L increments

of alum (as aluminum) (or equivalent

amounts of ferric salt) until the pH is

reduced to a level less than or equal to

the enhanced coagulation Step 2 target

pH shown in the following table:

ENHANCED COAGULATION STEP 2

TARGET PH

Alkalinity (mg/L as CaCO3) Target pH

0–60 .......................................... 5.5

>60–120 .................................... 6.3

>120–240 .................................. 7.0

>240 .......................................... 7.5

(iii) For waters with alkalinities of

less than 60 mg/L for which addition of

small amounts of alum or equivalent

addition of iron coagulant drives the pH

below 5.5 before significant TOC

removal occurs, the system must add

necessary chemicals to maintain the pH

between 5.3 and 5.7 in samples until the

TOC removal of 0.3 mg/L per 10 mg/L

alum added (as aluminum) (or

equivalant addition of iron coagulant) is

reached.

(iv) The system may operate at any

coagulant dose or pH necessary

(consistent with other NPDWRs) to

achieve the minimum TOC percent

removal approved under paragraph

(b)(3) of this section.

(v) If the TOC removal is consistently

less than 0.3 mg/L of TOC per 10 mg/

L of incremental alum dose (as

aluminum) at all dosages of alum (or

equivalant addition of iron coagulant),

the water is deemed to contain TOC not

amenable to enhanced coagulation. The

system may then apply to the State for

a waiver of enhanced coagulation

requirements.

(c) Compliance calculations. (1)

Subpart H systems other than those

identified in paragraph (a)(2) or (a)(3) of

this section must comply with

requirements contained in paragraph

(b)(2) of this section. Systems must

calculate compliance quarterly,

beginning after the system has collected

12 months of data, by determining an

annual average using the following

method:

(i) Determine actual monthly TOC

percent removal, equal to:

(1—(treated water TOC/source water

TOC)) × 100

(ii) Determine the required monthly

TOC percent removal (from either the

table in paragraph (b)(2) of this section

or from paragraph (b)(3) of this section).

(iii) Divide the value in paragraph

(c)(1)(i) of this section by the value in

paragraph (c)(1)(ii) of this section.

(iv) Add together the results of

paragraph (c)(1)(iii) of this section for

the last 12 months and divide by 12.

(v) If the value calculated in

paragraph (c)(1)(iv) of this section is less

than 1.00, the system is not in

compliance with the TOC percent

removal requirements.

(2) Systems may use the provisions in

paragraphs (c)(2)(i) through (v) of this

section in lieu of the calculations in

paragraph (c)(1)(i) through (v) of this

section to determine compliance with

TOC percent removal requirements.

(i) In any month that the system’s

treated or source water TOC level,

measured according to § 141.131(d)(3),

is less than 2.0 mg/L, the system may

assign a monthly value of 1.0 (in lieu of

the value calculated in paragraph

(c)(1)(iii) of this section) when

calculating compliance under the

provisions of paragraph (c)(1) of this

section.

(ii) In any month that a system

practicing softening removes at least 10

mg/L of magnesium hardness (as

CaCO3), the system may assign a
Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations 69475

monthly value of 1.0 (in lieu of the

value calculated in paragraph (c)(1)(iii)

of this section) when calculating

compliance under the provisions of

paragraph (c)(1) of this section.

(iii) In any month that the system’s

source water SUVA, prior to any

treatment and measured according to

§ 141.131(d)(4), is ≤2.0 L/mg-m, the

system may assign a monthly value of

1.0 (in lieu of the value calculated in

paragraph (c)(1)(iii) of this section)

when calculating compliance under the

provisions of paragraph (c)(1) of this

section.

(iv) In any month that the system’s

finished water SUVA, measured

according to § 141.131(d)(4), is ≤2.0 L/

mg-m, the system may assign a monthly

value of 1.0 (in lieu of the value

calculated in paragraph (c)(1)(iii) of this

section) when calculating compliance

under the provisions of paragraph (c)(1)

of this section.

(v) In any month that a system

practicing enhanced softening lowers

alkalinity below 60 mg/L (as CaCO3), the

system may assign a monthly value of

1.0 (in lieu of the value calculated in

paragraph (c)(1)(iii) of this section)

when calculating compliance under the

provisions of paragraph (c)(1) of this

section.

(3) Subpart H systems using

conventional treatment may also

comply with the requirements of this

section by meeting the criteria in

paragraph (a)(2) or (3) of this section.

(d) Treatment technique requirements

for DBP precursors. The Administrator

identifies the following as treatment

techniques to control the level of

disinfection byproduct precursors in

drinking water treatment and

distribution systems: For Subpart H

systems using conventional treatment,

enhanced coagulation or enhanced

softening.

11. Section 141.154 is amended by

adding paragraph (e) to read as follows:

§ 141.154 Required additional health

information.

* * * * *

(e) Community water systems that

detect TTHM above 0.080 mg/l, but

below the MCL in § 141.12, as an annual

average, monitored and calculated

under the provisions of § 141.30, must

include health effects language

prescribed by paragraph (73) of

appendix C to subpart O.

PART 142—NATIONAL PRIMARY

DRINKING WATER REGULATIONS

IMPLEMENTATION

12. The authority citation for part 142

continues to read as follows:

Authority: 42 U.S.C. 300f, 300g-1, 300g-2

300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j9, and 300j-11.

13. Section 142.14 is amended by

adding new paragraphs (d)(12), (d)(13),

(d)(14), (d)(15), and (d)(16) to read as

follows.

§ 142.14 Records kept by States.

* * * * *

(d) * * *

(12) Records of the currently

applicable or most recent State

determinations, including all supporting

information and an explanation of the

technical basis for each decision, made

under the following provisions of 40

CFR part 141, subpart L for the control

of disinfectants and disinfection

byproducts. These records must also

include interim measures toward

installation.

(i) States must keep records of

systems that are installing GAC or

membrane technology in accordance

with § 141.64(b)(2) of this chapter.

These records must include the date by

which the system is required to have

completed installation.

(ii) States must keep records of

systems that are required, by the State,

to meet alternative minimum TOC

removal requirements or for whom the

State has determined that the source

water is not amenable to enhanced

coagulation in accordance with

§ 141.135(b)(3) and (4) of this chapter,

respectively. These records must

include the alternative limits and

rationale for establishing the alternative

limits.

(iii) States must keep records of

subpart H systems using conventional

treatment meeting any of the alternative

compliance criteria in § 141.135(a)(2) or

(3) of this chapter.

(iv) States must keep a register of

qualified operators that have met the

State requirements developed under

§ 142.16(f)(2).

(13) Records of systems with multiple

wells considered to be one treatment

plant in accordance with § 141.132(a)(2)

of this chapter and § 142.16(f)(5).

(14) Monitoring plans for subpart H

systems serving more than 3,300

persons in accordance with § 141.132(f)

of this chapter.

(15) List of laboratories approved for

analyses in accordance with

§ 141.131(b) of this chapter.

(16) List of systems required to

monitor for disinfectants and

disinfection byproducts in accordance

with part 141, subpart L of this chapter.

The list must indicate what

disinfectants and DBPs, other than

chlorine, TTHM, and HAA5, if any, are

measured.

* * * * *

14. Section 142.16 is amended by

adding paragraph (h) to read as follows.

§ 142.16 Special primacy requirements.

* * * * *

(h) Requirements for States to adopt

40 CFR part 141, subpart L. In addition

to the general primacy requirements

elsewhere in this part, including the

requirement that State regulations be at

least as stringent as federal

requirements, an application for

approval of a State program revision

that adopts 40 CFR part 141, subpart L,

must contain a description of how the

State will accomplish the following

program requirements:

(1) Section 141.64(b)(2) of this chapter

(interim treatment requirements).

Determine any interim treatment

requirements for those systems electing

to install GAC or membrane filtration

and granted additional time to comply

with § 141.64 of this chapter.

(2) Section 141.130(c) of this chapter

(qualification of operators). Qualify

operators of public water systems

subject to 40 CFR part 141, subpart L.

Qualification requirements established

for operators of systems subject to 40

CFR part 141, subpart H—Filtration and

Disinfection may be used in whole or in

part to establish operator qualification

requirements for meeting 40 CFR part

141, subpart L requirements if the State

determines that the 40 CFR part 141,

subpart H requirements are appropriate

and applicable for meeting subpart L

requirements.

(3) Section 141.131(c)(2) of this

chapter (DPD colorimetric test kits).

Approve DPD colorimetric test kits for

free and total chlorine measurements.

State approval granted under

§ 141.74(a)(2) of this chapter for the use

of DPD colorimetric test kits for free

chlorine testing is acceptable for the use

of DPD test kits in measuring free

chlorine residuals as required in 40 CFR

part 141, subpart L.

(4) Sections 141.131(c)(3) and (d) of

this chapter (State approval of parties to

conduct analyses). Approve parties to

conduct pH, bromide, alkalinity, and

residual disinfectant concentration

measurements. The State’s process for

approving parties performing water

quality measurements for systems

subject to 40 CFR part 141, subpart H

requirements in paragraph (b)(2)(i)(D) of

this section may be used for approving

parties measuring water quality

parameters for systems subject to

subpart L requirements, if the State

determines the process is appropriate

and applicable.
69476 Federal Register / Vol. 63, No. 241 /Wednesday, December 16, 1998 /Rules and Regulations

(5) Section 141.132(a)(2) of this

chapter (multiple wells as a single

source). Define the criteria to use to

determine if multiple wells are being

drawn from a single aquifer and

therefore be considered a single source

for compliance with monitoring

requirements.

(6) Approve alternate minimum TOC

removal (Step 2) requirements, as

allowed under the provisions of

§ 141.135(b) of this chapter.

[FR Doc. 98–32887 Filed 12–15–98; 8:45 am]

BILLING CODE 6560–50–U