42160 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 131

[WH–FRL–5866–9]

RIN 2040–AC44

Water Quality Standards;

Establishment of Numeric Criteria for

Priority Toxic Pollutants for the State

of California

AGENCY: Environmental Protection

Agency.

ACTION: Proposed rule.

SUMMARY: This rule proposes for the

State of California, numeric water

quality criteria for priority toxic

pollutants necessary to fulfill the

requirements of section 303(c)(2)(B) of

the Clean Water Act (CWA) in the State

of California. This rule also proposes an

authorizing compliance schedule

provision.

EPA is proposing this rule based on

the Administrator’s determination that

criteria are necessary in the State of

California to meet the requirements of

CWA section 303(c)(2)(B). This section

of the CWA requires states to adopt

numeric water quality criteria for

priority toxic pollutants for which EPA

has issued CWA section 304(a) criteria

guidance and whose presence or

discharge could reasonably be expected

to interfere with designated uses.

Priority toxic pollutants are identified in

40 CFR 131.36.

EPA is proposing this rule to fill a gap

in California water quality standards

that was created in 1994 when a State

Court overturned the State’s water

quality control plans which contained

water quality criteria for priority toxic

pollutants for which EPA had issued

CWA section 304(a) criteria guidance.

Thus, the State of California is currently

without numeric water quality criteria

for many priority toxic pollutants as

required by the CWA, necessitating this

action by EPA.

When these proposed federal criteria

take effect, they will create legally

applicable water quality standards in

the State of California for inland surface

waters, enclosed bays and estuaries for

all purposes and programs under the

CWA.

DATES: All written comments received

on or before September 26, 1997 will be

considered in the preparation of the

final rule. A public hearing will be held

on September 17, 1997, in San

Francisco, California, and on September

18, 1997, in Los Angeles, California.

Both oral and written comments will be

accepted at the hearings.

ADDRESSES: Written comments should

be addressed to Diane E. Frankel, P.E.,

Esq., California Toxics Rule Project

Manager, U.S. Environmental Protection

Agency, Region 9 (WTR–5), Water

Management Division, 75 Hawthorne

Street, San Francisco, California 94105.

Written comments are encouraged on

paper or computer disk by mail. Faxed

comments will not be accepted. For

comments on paper, an original and two

copies must be submitted. For

computerized comments, Wordperfect

or ASCII format must be used.

Comments previously submitted for

other Federal Register notices which are

relevant to this notice must be

resubmitted in their entirety to be

considered for this proposed action.

A public hearing will be held at

USEPA Region 9, 75 Hawthorne Street,

San Francisco, California, 94105, from

1–5 p.m. on September 17, 1997. A

public hearing will also be held at the

Los Angeles Department of Water and

Power, 111 North Hope Street, Los

Angeles, California, 90012, from 1–5

p.m. on September 18, 1997.

The public may inspect the

administrative record for this

rulemaking, including documentation

supporting the aquatic life and human

health criteria, at the U.S.

Environmental Protection Agency,

Region 9, Water Management Division,

75 Hawthorne Street, San Francisco

94105 (telephone: 415–744–2125) on

weekdays during the Agency’s normal

business hours of 8:00 a.m. to 4:30 p.m.

A reasonable fee will be charged for

photocopies.

FOR FURTHER INFORMATION CONTACT:

Diane E. Frankel, P.E., Esq. or Philip

Woods, U.S. Environmental Protection

Agency, Region 9 (WTR–5), Water

Management Division, 75 Hawthorne

Street, San Francisco, California 94105,

415–744–2004 or 415–744–1997,

respectively.

SUPPLEMENTARY INFORMATION: This

preamble is organized according to the

following outline:

A. Introduction and Overview

1. Introduction

2. Overview

B. Statutory and Regulatory Background

C. State of California Actions and

Compliance Regarding Section

303(c)(2)(B) of the Clean Water Act

(CWA)

1. California Regional Water Quality

Control Board Basin Plans, and the

Inland Surface Waters Plan (ISWP) and

the Enclosed Bays and Estuaries Plan

(EBEP) of April 1991

2. EPA’s Review of California Water

Quality Standards for Priority Toxic

Pollutants in the ISWP and EBEP, and

the National Toxics Rule

3. Status of Implementation of CWA

Section 303(c)(2)(B)

4. State-Adopted Site-Specific Priority

Toxic Pollutant Criteria

D. Rationale and Approach For Developing

the Proposed Rule

1. Legal Basis

2. Approach for Developing the Proposed

Rule

E. Derivation of Criteria

1. Section 304(a) Criteria Guidance Process

2. Aquatic Life Criteria

a. Freshwater Criteria

b. Freshwater Acute Selenium Criterion

c. Dissolved Metals Criteria

d. Application of Metals Criteria

e. Saltwater Copper Criteria

f. Chronic Averaging Period

g. Hardness

3. Human Health Criteria

a. 2,3,7,8–TCDD (Dioxin) Criteria

b. Arsenic Criteria

c. Mercury Criteria

d. Polychlorinated Biphenyls (PCBs)

Criteria

e. Section 304(a) Human Health Criteria

Excluded

f. Cancer Risk Level

F. Description of the Proposed Rule

1. Scope

2. EPA Criteria for Priority Toxic Pollutants

3. Implementation

4. Wet Weather Flows

5. Schedules of Compliance

G. Executive Order (E.O.) 12866, Regulatory

Planning and Review

1. Baselines

2. Costs

3. Benefits

H. Executive Order (E.O.) 12875, Enhancing

the Intergovernmental Partnership

I. The Unfunded Mandates Reform Act of

1995

J. The Regulatory Flexibility Act

K. The Paperwork Reduction Act

L. The Endangered Species Act

Potentially Affected Entities: Citizens

concerned with water quality in

California may be interested in this

rulemaking. Entities discharging

pollutants to waters of the United States

in California could be indirectly affected

by this rulemaking since water quality

criteria are used to create water quality

standards which in turn are used in

developing National Pollutant Discharge

Elimination System (NPDES) permit

limits. Categories and entities which

may ultimately be indirectly affected

include:

Category

Examples of potentially

indirectly affected entities

Industry ................. Industries discharging

pollutants to surface

waters in California.

Municipalities ........ Publicly-owned treatment works discharging pollutants to surface waters in California.
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42161

This table is not intended to be

exhaustive, but rather provides a guide

for readers regarding NPDES regulated

entities likely to be indirectly affected

by this action. This table lists the types

of entities that EPA is now aware could

potentially be indirectly affected by this

action. If you have questions regarding

this section consult the person listed in

the preceding FOR FURTHER INFORMATION

CONTACT section.

A. Introduction and Overview

1. Introduction

This section of the preamble

introduces the topics which are

addressed below and provides a brief

overview of EPA’s basis and rationale

for proposing federal criteria for the

State of California. Section B briefly

describes the evolution of the efforts to

control toxic pollutants; these efforts

include the changes enacted in the 1987

CWA Amendments which are the basis

for this rule. Section C summarizes

California’s efforts since 1987 to

implement the requirements of CWA

section 303(c)(2)(B) and describes EPA’s

procedure and actions for determining

whether California has fully

implemented CWA section 303(c)(2)(B).

Section D provides the rationale and

approach for developing the proposed

rule, including a discussion of EPA’s

legal basis for this proposal. Section E

describes the development of the

criteria included in this rule. Section F

summarizes the provisions of the

proposed rule and discusses

implementation issues. Sections G, H, I,

J, K, and L briefly address the

requirements of Executive Orders 12866

and 12875, the Unfunded Mandates

Reform Act of 1995, the Regulatory

Flexibility Act, the Paperwork

Reduction Act, and the Endangered

Species Act, respectively.

Since detailed information concerning

many of the topics in this preamble was

published previously in the Federal

Register in preambles for other

rulemakings, references are frequently

made to those preambles. Those

rulemakings include: Water Quality

Standards; Establishment of Numeric

Criteria for Priority Toxic Pollutants, 57

FR 60848, December 22, 1992 (referred

to as the National Toxics Rule or NTR);

and the NTR as amended by

Administrative Stay of Federal Water

Quality Criteria for Metals and Interim

Final Rule, Water Quality Standards;

Establishment of Numeric Criteria for

Priority Toxic Pollutants; States’

Compliance—Revision of Metals

Criteria, 60 FR 22228, May 4, 1995

(referred to as the National Toxics Rule

[NTR], as amended). The NTR, as

amended, is codified at 40 CFR 131.36.

A copy of the NTR, as amended, and its

preambles are contained in the

administrative record for this

rulemaking.

2. Overview

This proposed rule would establish

ambient water quality criteria for

priority toxic pollutants in the State of

California. The criteria in this proposal

would supplement the water quality

criteria promulgated for California in

the NTR, as amended. In 1991, EPA

approved a number of water quality

criteria (discussed in section C, below),

for the State of California. Since EPA

had approved these criteria, it was not

necessary to include them in the NTR.

However, the EPA-approved criteria

were subsequently invalidated in State

litigation. Thus, this proposal contains

criteria to fill the gap created by the

State litigation.

This proposed rule does not change or

supersede any criteria previously

promulgated for the State of California

in the NTR, as amended. Criteria which

EPA promulgated for California in the

NTR, as amended, are footnoted in the

proposed table at 131.38(b)(1), so that

when this proposed rule is promulgated,

readers may see the criteria promulgated

in the NTR, as amended, for California

and the criteria promulgated through

this rulemaking for California in the

same table.

This proposed rule is not intended to

apply to waters within Indian Country.

EPA recognizes that there are possibly

waters located wholly or partly in

Indian Country that are included in the

State’s basin plans. EPA will work with

the State and Tribes to identify any such

waters and to seek comment from those

entities on whether EPA should include

those waters in the final rulemaking or

take other actions to protect water

quality in Indian Country. EPA also

solicits comment from the public on this

approach.

This rule is important for several

environmental, programmatic and legal

reasons. Control of toxic pollutants in

surface waters is necessary to achieve

the CWA’s goals and objectives. Many of

California’s monitored river miles, lake

acres, and estuarine waters have

elevated levels of toxic pollutants.

Recent studies on California water

bodies indicate that elevated levels of

toxic pollutants exist in fish tissue

which result in fishing advisories or

bans. These toxic pollutants can be

attributed to, among other sources,

industrial and municipal discharges.

Water quality standards for toxic

pollutants are important to State and

EPA efforts to address water quality

problems. Clearly established water

quality goals enhance the effectiveness

of many of the State’s and EPA’s water

programs including permitting, coastal

water quality improvement, fish tissue

quality protection, nonpoint source

controls, drinking water quality

protection, and ecological protection.

Numeric criteria for toxic pollutants

allow the State and EPA to evaluate the

adequacy of existing and potential

control measures to protect aquatic

ecosystems and human health. Numeric

criteria also provide a more precise

basis for deriving water quality-based

effluent limitations in National

Pollutant Discharge Elimination System

(NPDES) permits to control toxic

pollutant discharges. Congress

recognized these issues when it enacted

section 303(c)(2)(B) to the CWA.

While California recognizes the need

for applicable water quality standards

for toxic pollutants, its adoption efforts

have been stymied by a variety of

factors. The Administrator has

determined that it must exercise its

CWA authorities to move forward the

toxic control program, consistent with

the CWA and with the State of

California’s water quality standards

program.

EPA’s action will also help restore

equity among the states. The CWA is

designed to ensure all waters are

sufficiently clean to protect public

health and/or the environment. The

CWA allows some flexibility and

differences among states in their

adopted and approved water quality

standards, but it should be implemented

in a manner that ensures a level playing

field among states. Although California

has made important progress toward

satisfying CWA requirements, it has not

satisfied CWA section 303(c)(2)(B) by

adopting water quality standards for

toxic pollutants. This section was added

to the CWA by Congress in 1987. The

State of California is the only state in

the Nation for which CWA section

303(c)(2)(B) remains substantially

unimplemented after EPA’s

promulgation of the NTR in December

of 1992. Section 303(c)(4) of the CWA

authorizes the EPA Administrator to

promulgate standards where necessary

to meet the requirements of the Act.

EPA has determined that this rule is a

necessary and important component for

the implementation of CWA section

303(c)(2)(B) in California.

EPA acknowledges that the State of

California is working to satisfy CWA

section 303(c)(2)(B). When the State

formally adopts criteria consistent with

its statutory requirements, as envisioned

by Congress in the CWA, EPA will act

to stay its rule. When any judicial
42162 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

review of such State standards is

complete and sustains the State

standards, EPA will act to withdraw its

rule.

B. Statutory and Regulatory

Background

Section 303(c) of the 1972 Federal

Water Pollution Control Act

Amendments (FWPCA) established the

statutory basis for the current water

quality standards program. Although the

major innovation of the 1972 FWPCA

was technology-based controls,

Congress maintained the concept of

water quality standards both as a

mechanism to establish goals for the

Nation’s waters and as a regulatory

requirement when standardized

technology controls for point source

discharges and/or nonpoint source

controls were inadequate.

Another major innovation in the 1972

FWPCA was the establishment of the

National Pollutant Discharge

Elimination System (NPDES) which

requires point source dischargers to

obtain a permit before legally

discharging to waters of the United

States. In addition to the permit limits

established on the basis of technology

(e.g. effluent limitations guidelines), the

Act requires permits to include more

stringent limits as necessary to meet

instream water quality standards. See

CWA section 301(b)(1)(C).

Water quality standards are

comprised of designated uses, criteria to

meet those uses, and an antidegradation

policy. Water quality standards serve

two main functions: they allow for

assessment of water quality in a water

body and they provide a basis for

determining what effluent discharge

limitations may be allowed in order to

protect the designated uses of the water

body.

In its initial efforts to control toxic

pollutants, the FWPCA, pursuant to

section 307, required EPA to designate

a list of toxic pollutants and to establish

toxic pollutant effluent standards based

on a formal rulemaking record. Such

rulemaking required formal hearings.

EPA struggled with this unwieldy

process and ultimately promulgated

effluent standards for six toxic

pollutants, pollutant families or

mixtures. See 40 CFR Part 129. Congress

amended section 307 in the 1977 CWA

Amendments by endorsing the Agency’s

alternative procedure of regulating toxic

pollutants by use of technology-based

effluent limitations guidelines for toxic

pollutants, by amending the procedure

for establishing toxic pollutant effluent

standards to provide for more flexibility

in the hearing process for establishing a

record, and by directing the Agency to

include sixty-five specific pollutants or

classes of pollutants on the toxic

pollutant list. EPA published the

required list on January 31, 1978 (43 FR

4109). This toxic pollutant list was the

basis on which EPA focused its efforts

on criteria development for toxic

pollutants.

EPA selected key chemicals of

concern within the sixty-five families of

pollutants and identified a more specific

list of 129 priority toxic pollutants. Two

volatile chemicals and one water

unstable chemical were removed from

the list (see 46 FR 2266, January 8, 1981;

46 FR 10723, February 4, 1981), so that

at present, there are 126 priority toxic

pollutants. This list appears in 40 CFR

131.36.

Another critical section of the 1972

FWPCA was section 304(a). CWA

section 304(a)(1) provides, in part, that

EPA develop and publish criteria

guidance for water quality reflecting the

latest scientific knowledge on the kind

and extent of all identifiable effects on

health and welfare including, but not

limited to, plankton, fish, shellfish,

wildlife, plant life, shorelines, beaches,

esthetics, and recreation which may be

expected from the presence of

pollutants, and on the effects of

pollutants on biological community

diversity, productivity, etc.

In order to avoid confusion, it must be

recognized that the CWA uses the term

‘‘criteria’’ in two separate ways. In CWA

section 303(c), which is discussed

above, the term is part of the definition

of a water quality standard. That is, a

water quality standard is comprised of

designated uses and the criteria

necessary to protect those uses. The

term ‘‘criteria’’ refers to the ambient

component of the water quality standard

contained in state or federal law.

However, CWA section 304(a)(1) directs

EPA to publish water quality ‘‘criteria’’

guidance which encompass scientific

assessments of the health and ecological

effects of various pollutants listed

pursuant to CWA section 307(a)(1) and

which are used to support development

of ambient criteria as part of water

quality standards. CWA section 304(a)

criteria guidance are intended as

guidance only and have no binding

effect. States may consider these criteria

guidance in adopting regulatory criteria.

To implement CWA section 304(a)(1),

EPA initially produced a series of

scientific water quality criteria guidance

documents. EPA’s most recently

published criteria documents are

summarized in one document entitled,

Quality Criteria for Water 1986 (1986

‘‘Gold Book’’). EPA has updated many

of the criteria since publication of the

1986 Gold Book. EPA’s criteria guidance

(both the earlier documents and updates

including those in the Agency’s

Integrated Risk Information System

[IRIS]), provide a comprehensive

toxicological evaluation of each

chemical and the individual criteria

recommendations, as updated, are the

official guidance. For toxic pollutants,

the recommendations tabulate the

relevant acute and chronic toxicity

information for aquatic life and derive

the criteria maximum concentrations

(acute criteria) and criteria continuous

concentrations (chronic criteria) which

the Agency recommends to protect

aquatic life resources. For human health

criteria, the recommendations provide

the appropriate reference doses, and if

appropriate, the carcinogenic slope

factors, and derives recommended

criteria. The details of this process are

discussed in a later part of this

preamble.

Criteria documents, along with any

more recent scientific data and

information, may be used to interpret a

state’s narrative criterion pursuant to 40

CFR 122.44(d)(1)(vi), and serve to

establish State and EPA permit

discharge limits pursuant to CWA

section 301(b)(1)(C) which requires

NPDES permits to contain limitations

required to implement any applicable

water quality standard established in

the CWA.

In support of the November, 1983

water quality standards rulemaking,

EPA issued program guidance entitled,

Water Quality Standards Handbook

(December 1983) simultaneously with

the publication of the final rule. The

forward to that guidance noted EPA’s

two-fold water quality based approach

to controlling toxic pollutants: chemical

specific numeric criteria and biological

testing in whole effluent or ambient

waters to comply with narrative ‘‘no

toxics in toxic amounts’’ standards.

More detailed programmatic guidance

on the application of biological testing

was provided in the Technical Support

Document for Water Quality-Based

Toxics Control (TSD) (EPA 440/4–85–

032, September 1985). This document

provided the needed information to

convert chemical specific and

biologically based criteria into water

quality standards for ambient receiving

waters and permit limits for discharges

to those waters. The TSD focused on the

use of toxicity testing of effluent (whole

effluent testing or WET methods) to

develop effluent limitations within

discharge permits. Such effluent limits

were designed to implement the ‘‘free

from toxicity’’ narrative standards in

state water quality standards. The TSD

also focused on water quality standards.

Procedures and policy were presented
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42163

for appropriate design flows for EPA’s

section 304(a) acute and chronic

criteria. In 1991, EPA revised and

expanded the TSD. (Technical Support

Document for Water Quality-Based

Toxics Control (TSD), (EPA 505/2–90–

001, March 1991).) A notice of

availability was published in the

Federal Register on April 4, 1991 (56 FR

13827). All references in this preamble

are to the revised TSD.

In 1987, Congress enacted stringent

new water quality standard provisions

in the Water Quality Act amendments.

The 1987 Amendments to the CWA

(P.L. 100–4) added section 303(c)(2)(B)

which provides:

Whenever a State reviews water quality

standards pursuant to paragraph (1) of this

subsection, or revises or adopts new

standards pursuant to this paragraph, such

State shall adopt criteria for all toxic

pollutants listed pursuant to section 307(a)(1)

of this Act for which criteria have been

published under section 304(a), the discharge

or presence of which in the affected waters

could reasonably be expected to interfere

with those designated uses adopted by the

State, as necessary to support such

designated uses. Such criteria shall be

specific numerical criteria for such toxic

pollutants. Where such numerical criteria are

not available, whenever a State reviews water

quality standards pursuant to paragraph (1),

or revises or adopts new standards pursuant

to this paragraph, such State shall adopt

criteria based on biological monitoring or

assessment methods consistent with

information published pursuant to section

304(a)(8). Nothing in this section shall be

construed to limit or delay the use of effluent

limitations or other permit conditions based

on or involving biological monitoring or

assessment methods or previously adopted

numerical criteria.

The addition of this new requirement

to the existing water quality standards

review and revision process of CWA

section 303(c) did not change the

existing procedural or timing

provisions. CWA section 303(c)(1) still

required that states review their water

quality standards at least once each

three year period and transmit the

results to EPA for review. EPA’s

oversight and promulgation authorities

and statutory schedules in CWA section

303(c)(4) were likewise unchanged.

Rather, the provision required the states

to place heavy emphasis on adopting

numeric chemical-specific criteria for

toxic pollutants (rather than narrative

approaches) during the next triennial

review. Congress was frustrated that

states were not using the numerous

CWA section 304(a) criteria guidance

that EPA had and was continuing to

develop, to assist states in controlling

the discharge of priority toxic

pollutants. Accordingly, Congress

explicitly mandated that states adopt

numeric criteria for toxic pollutants

where the discharge or presence of such

pollutants could reasonably be expected

to interfere with such designated uses.

In response to this requirement, EPA

strengthened its efforts to assist state

adoption of water quality standards for

priority toxic pollutants. This included

developing and issuing guidance for

states on acceptable implementation

procedures for several new sections of

the CWA, including sections

303(c)(2)(B) and 304(l). EPA, in devising

guidance for CWA section 303(c)(2)(B),

attempted to provide states the

maximum flexibility that complied with

the express statutory language but also

with the overriding Congressional

objective: Prompt adoption and

implementation of numeric toxic

pollutant criteria where necessary to

protect designated uses. EPA believed

that flexibility was important so that

each state could satisfy CWA section

303(c)(2)(B) and to the extent possible,

accommodate its existing water quality

standards regulatory approach. EPA’s

program guidance was issued in final

form on December 12, 1988 and the

availability of the guidance was

published in a Federal Register notice

on January 5, 1989 (54 FR 346).

EPA’s section 303(c)(2)(B) program

guidance identified several options that

could be used by a state to meet the

requirement that the state adopt toxic

pollutant criteria ‘‘* * *the discharge

or presence of which in the affected

waters could reasonably be expected to

interfere with those designated uses

adopted by the State, as necessary to

support such designated uses.’’ These

options are fully discussed in the

guidance and in the preamble to the

National Toxics Rule (NTR) at 57 FR

60853. One option is for a state to adopt

statewide numeric criteria for all section

307(a) toxic pollutants for which EPA

has developed section 304(a) criteria

guidance, regardless of whether the

pollutants are known to be present. This

option is the most comprehensive

approach to satisfy the statutory

requirement, and ensures

comprehensive coverage of the priority

toxic pollutants with scientifically

defensible criteria. This option would

not impose more effluent limits on

dischargers than any other option,

because permit limits would only be

based on the regulation of the particular

toxic pollutants in their discharge and

not on the total listing in the water

quality standards. Actual permit limits

should be the same under any option.

EPA’s December 1988 guidance also

stated that all state standards triennial

reviews initiated after passage of the

amended CWA must include a

consideration of numeric toxic criteria.

Beyond the increased Congressional

and public concern about the relative

importance of toxic pollutant controls,

there was increased evidence of toxic

pollution problems in our Nation’s

waters. In response, in 1992, EPA

promulgated the NTR pursuant to CWA

section 303(c)(4)(B) and 40 CFR

131.22(b) to rectify program deficiencies

in 14 states, including the State of

California. The State of California was

included for specific pollutants and for

specific water bodies which

corresponded with EPA’s disapproval in

November 1991 of a portion of each of

two statewide plans. EPA did not

promulgate criteria for those portions of

the statewide plans which it approved.

Today’s action proposes to add

priority toxic pollutant criteria

applicable to inland surface waters,

enclosed bays and estuaries within the

State of California.

C. State of California Actions and

Compliance Regarding Section

303(c)(2)(B) of the Clean Water Act

(CWA)

1. California Regional Water Quality

Control Board Basin Plans, and the

Inland Surface Waters Plan (ISWP) and

the Enclosed Bays and Estuaries Plan

(EBEP) of April 1991

The State of California regulates water

quality through its State Water Resource

Control Board (SWRCB) and through

nine Regional Water Quality Control

Boards (RWQCBs). Each of the nine

RWQCBs represents a different

geographic area; area boundaries are

generally along watershed boundaries.

Each RWQCB maintains a Basin Plan

which contains the designated uses of

the water bodies within its respective

geographic area within California. These

designated uses (or ‘‘beneficial uses’’

under State law) together with legallyadopted criteria (or ‘‘objectives’’ under

State law), comprise water quality

standards for the water bodies within

each of the Basin areas. Each of the nine

RWQCBs undergoes a triennial Basin

Planning review process, in compliance

with CWA section 303. The SWRCB

provides assistance to the RWQCBs.

Most of the Basin Plans contain

conventional pollutant objectives such

as dissolved oxygen. None of the Basin

Plans contains a comprehensive list of

priority toxic pollutant criteria to satisfy

CWA section 303(c)(2)(B). The nine

RWQCBs and the SWRCB had intended

that the priority toxic pollutant criteria

contained in the three SWRCB statewide

plans, the Inland Surface Water Plan

(ISWP), the Enclosed Bay and Estuary
42164 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

Plan (EBEP), and the Ocean Plan, apply

to all Basins and satisfy CWA section

303(c)(2)(B).

On April 11, 1991, the SWRCB

adopted two statewide water quality

control plans, the ISWP and the EBEP.

These statewide plans contained

narrative and numeric water quality

criteria for toxic pollutants, in part to

satisfy CWA section 303(c)(2)(B). The

water quality criteria contained in the

SWRCB statewide plans, together with

the designated uses in each of the Basin

Plans, created a set of water quality

standards for waters within for the State

of California.

Specifically, the two plans established

water quality criteria or objectives for all

fresh waters, bays and estuaries in the

State. The plans contained water quality

criteria for some priority toxic

pollutants, provisions relating to whole

effluent toxicity, implementation

procedures for point and nonpoint

sources, and authorizing compliance

schedule provisions. The plans also

included special provisions affecting

waters dominated by reclaimed water

(labeled as Category (a) waters), and

waters dominated by agricultural

drainage and constructed agricultural

drains (labeled as Category (b) and (c)

waters, respectively).

2. EPA’s Review of California Water

Quality Standards for Priority Toxic

Pollutants in the ISWP and EBEP, and

the National Toxics Rule

The EPA Administrator has delegated

the responsibility and authority for

review and approval or disapproval of

all new or revised state water quality

standards to the EPA Regional

Administrators (see 40 CFR 131.21).

Thus, state actions under CWA section

303(c)(2)(B) are submitted to the

appropriate EPA Regional Administrator

for review and approval.

In mid-April 1991, the SWRCB

submitted to EPA for review and

approval the two statewide water

quality control plans—the ISWP and the

EBEP. On November 6, 1991, EPA

Region 9 formally concluded its review

of the SWRCB’s plans. EPA approved

the narrative water quality criterion and

the toxicity criterion in each of the

plans. EPA also approved the numeric

water quality criteria contained in both

plans, finding them to be consistent

with the requirements of section

303(c)(2)(B) of the CWA and with EPA’s

national criteria guidance published

pursuant to section 304(a) of the CWA.

EPA noted the lack of criteria for

some pollutants, and found that,

because of the omissions, the plans did

not fully satisfy CWA section

303(c)(2)(B). The plans did not contain

criteria for all listed pollutants for

which EPA had published national

criteria guidance. The ISWP contained

human health criteria for only 65

pollutants, and the EBEP contained

human health criteria for only 61

pollutants for which EPA had issued

section 304(a) guidance criteria. Both

the ISWP and EBEP contained aquatic

life criteria for all pollutants except

cyanide and chromium III (freshwater

only) for which EPA has CWA section

304(a) criteria guidance. The SWRCB’s

administrative record stated that all

priority pollutants with EPA criteria

guidance were likely to be present in

California waters. However, the

SWRCB’s record contained insufficient

information to support a finding that the

excluded pollutants were not reasonably

expected to interfere with designated

uses of the waters of the State.

Although EPA approved the statewide

selenium objective in the ISWP and

EBEP, EPA disapproved the criteria for

the San Francisco Bay and Delta,

because there was clear evidence that

the criteria would not protect the

designated fish and wildlife uses (the

California Department of Health

Services had issued waterfowl

consumption advisories due to selenium

concentrations, and scientific studies

had documented selenium toxicity to

fish and wildlife). EPA restated its

commitment to object to National

Pollutant Discharge Elimination System

(NPDES) permits issued for San

Francisco Bay that contained effluent

limits based on an objective greater than

5 ppb (four day average) and 20 ppb (1

hour average), the freshwater criteria.

EPA reaffirmed its disapproval of sitespecific selenium criteria for portions of

the San Joaquin River, Salt Slough, and

Mud Slough. EPA also disapproved of

the categorical deferrals and

exemptions. These disapprovals

included the disapproval of the State’s

deferral of water quality objectives to

effluent dominated streams (Category a)

and to streams dominated by

agricultural drainage (Category b), and

the disapproval of the exemption of

water quality objectives to constructed

agricultural drains (Category c). EPA

found the definitions of the categories

imprecise and overly broad which could

have led to an incorrect interpretation.

Since EPA had disapproved portions

of each of the California statewide plans

which were necessary to satisfy CWA

section 303(c)(2)(B), California was

included in EPA’s promulgation of the

National Toxics Rule (NTR) (40 CFR

131.36, 57 FR 60848). EPA promulgated

specific criteria for certain water bodies

in California.

The NTR was amended, effective

April 14, 1995, to stay certain metals

criteria which had been promulgated as

total recoverable; effective April 15,

1995, EPA promulgated interim final

metals criteria as dissolved

concentrations for those metals which

had been stayed (Administrative Stay of

Federal Water Quality Criteria for

Metals and Interim Final Rule, Water

Quality Standards; Establishment of

Numeric Criteria for Priority Toxic

Pollutants; States’ Compliance—

Revision of Metals Criteria; 60 FR

22228, May 4, 1995 [the NTR, as

amended]). The stay was in response to

a lawsuit against EPA challenging,

among other issues, metals criteria

expressed as total recoverable

concentrations. A partial Settlement

Agreement required EPA to stay specific

metals criteria in the NTR. EPA then

promulgated certain metals criteria in

the dissolved form through the use of

conversion factors. These factors are

listed in the NTR, as amended. A

scientific discussion of these criteria is

found in the next section.

Since certain criteria have already

been promulgated for specific water

bodies in the State of California in the

NTR, as amended, they are not within

the scope of today’s proposed rule.

However, for clarity in reading a

comprehensive rule for the State of

California, these criteria are

incorporated in proposed 40 CFR

131.38(d)(2). Footnotes to the Table in

proposed 40 CFR 131.38(b)(1) and

proposed 40 CFR 131.38(d)(3) clarify

which criteria (and for which specific

water bodies) have been promulgated by

the NTR, as amended, and are therefore

excluded from this proposed rule. The

appropriate (freshwater or saltwater)

aquatic life criteria which were

promulgated in the NTR, as amended,

for all inland surface waters and

enclosed bays and estuaries include:

chromium III and cyanide. The

appropriate (water and organism or

organism only) human health criteria

which were promulgated in the NTR, as

amended, for all inland surface waters

and enclosed bays and estuaries

include: antimony; thallium; asbestos;

acrolein; acrylonitrile; carbon

tetrachloride; chlorobenzene; 1,2-

dichloroethane; 1,1-dichloroethylene;

1,3-dichloropropylene; ethylbenzene;

1,1,2,2-tetrachloroethane;

tetrachloroethylene; 1,1,2-

trichloroethane; trichloroethylene; vinyl

chloride; 2,4-dichlorophenol; 2-methyl4,6-dinitrophenol; 2,4-dinitrophenol;

benzidine; bis(2-chloroethyl)ether;

bis(2-ethylhexyl)phthalate; 3,3-

dichlorobenzidine; diethyl phthalate;
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42165

dimethyl phthalate; di-n-butyl

phthalate; 2,4-dinitrotoluene; 1,2-

diphenylhydrazine;

hexachlorobutadiene;

hexachlorocyclopentadiene;

hexachloroethane; isophorone;

nitrobenzene; n-nitrosodimethylamine;

and n-nitrosodiphenylamine. Other

pollutant criteria were promulgated in

the NTR, as amended, for specific water

bodies, but not all inland surface waters

and enclosed bays and estuaries.

3. Status of Implementation of CWA

Section 303(c)(2)(B)

Shortly after the SWRCB adopted the

ISWP and EBEP, several dischargers

filed suit against the State alleging that

it had not adopted the two plans in

compliance with State law. The

plaintiffs in a consolidated case

included: the County of Sacramento,

Sacramento County Water Agency;

Sacramento Regional County Sanitation

District; the City of Sacramento; the City

of Sunnyvale; the City of San Jose; the

City of Stockton; and Simpson Paper

Company.

The dischargers alleged that the State

had not adopted the ISWP and EBEP in

compliance with the California

Administrative Procedures Act (Gov

Code. Section 11340, et seq.), the

California Environmental Quality Act

(Pub. Re Code, Section 21000, et seq.),

and the Porter-Cologne Act (Wat. Code,

Section 13200, et seq.). The allegation

that the State did not sufficiently

consider economics when adopting

water quality objectives, as allegedly

required by Section 13241 of the Porter

Cologne Act, was an important issue in

the litigation.

In October of 1993, the Superior Court

of California, County of Sacramento,

issued a tentative decision in favor of

the dischargers. In March of 1994, the

Court issued a substantively similar

final decision in favor of the

dischargers. Final judgments from the

Court in July of 1994 ordered the

SWRCB to rescind the ISWP and EBEP.

On September 22, 1994, the SWRCB

formally rescinded the two statewide

water quality control plans. The State is

currently in the process of readopting

water quality control plans for inland

surface waters, enclosed bays and

estuaries.

CWA section 303(c)(2)(B) was fully

implemented in the State of California

from December of 1992, when the NTR

was promulgated, until September of

1994, when the SWRCB was required to

rescind the ISWP and EBEP. The

provisions for California in EPA’s NTR

together with the approved portions of

California’s ISWP and EBEP

implemented the requirements of CWA

section 303(c)(2)(B). However, since

September of 1994, when the SWRCB

rescinded the ISWP and EBEP, the

requirements of section 303(c)(2)(B)

have not been fully implemented in

California.

The scope of today’s rule is to reestablish criteria for the remaining

priority toxic pollutants to meet the

requirements of section 303(c)(2)(B) of

the CWA. Pursuant to section 303(c)(4),

the Administrator has determined that it

is necessary to include in today’s

proposed action criteria for priority

toxic pollutants, which are not covered

by the NTR, as amended, or by the State

through site-specific criteria, for waters

of the United States in the State of

California.

4. State-Adopted Site-Specific Priority

Toxic Pollutant Criteria

The State has the discretion to

develop site-specific criteria when

appropriate e.g., when statewide criteria

appear over- or under-protective of

designated uses. Periodically, the State

through its RWQCBs will adopt sitespecific criteria for priority toxic

pollutants within respective Basin

Plans. These criteria are intended to be

effective throughout the Basin or

throughout a designated water body.

Under California law, these criteria

must be publicly reviewed and

approved by the RWQCB, the SWRCB,

and the State’s Office of Administrative

Law (OAL). Once this adoption process

is complete, the criteria become State

law.

These criteria must be submitted to

the EPA Regional Administrator for

review and approval under CWA

section 303. These criteria are usually

submitted to EPA as part of a RWQCB

Basin Plan Amendment, after the

Amendment has been adopted under

the State’s process and has become State

law.

State-Adopted Site-Specific Criteria

Under EPA Review: Basin Plan Updates:

The State of California has recently

reviewed and updated all of its RWQCB

Basin Plans. All of these Basin Plans

have completed the State review and

adoption process and have been

submitted to EPA for review and

approval. Some of the Basin Plans

contain site-specific criteria. In these

cases, the State-adopted site-specific

criteria are used for water quality

programs.

EPA Region 9 intends to make a

determination on all State-adopted, sitespecific criteria that are currently under

EPA review. If, after this proposal, but

before promulgation of this final rule,

EPA approves any State-adopted sitespecific criteria, the EPA Administrator

may make a finding in the final rule that

it will be unnecessary to promulgate

criteria for those site-specific pollutants

and associated water bodies. If EPA

disapproves any State-adopted sitespecific criteria, today’s proposed

statewide criteria would apply for those

pollutants and associated water bodies.

However, if EPA promulgates

statewide federal criteria as proposed in

this rule, prior to a decision on any

State-adopted site-specific criteria, the

more stringent of the two criteria would

be used for water quality programs. Both

federal and State water quality programs

must be satisfied, and application of the

more stringent of the two criteria would

satisfy both.

Santa Ana River: EPA is currently

reviewing State-adopted site-specific

criteria for copper, cadmium and lead

for portions of the Santa Ana River.

These criteria are contained in the Santa

Ana Region Basin Plan Amendments

(RWQCB for the Santa Ana Region).

EPA intends to complete its review and

make a final determination on these

site-specific criteria prior to the

promulgation of this rule.

If EPA approves the State-adopted

site-specific criteria, the EPA

Administrator can make a finding in the

final rule that it will be unnecessary to

promulgate federal criteria for those

site-specific pollutants and associated

water bodies. If EPA disapproves the

State-adopted site-specific criteria,

today’s proposed statewide criteria,

when promulgated final, would apply

for those pollutants and water bodies.

State-Adopted Site-Specific Criteria

with EPA Approval: In several cases, the

EPA Regional Administrator has

reviewed and approved of State-adopted

site-specific criteria within the State of

California. Three of these cases are

discussed below separately.

Unfortunately, EPA does not have a

complete listing of all of the site-specific

criteria that may remain in place as

State law after the State court decision

vacated the ISWP and the EBEP.

Consequently, EPA is proposing these

criteria for all waters, except for those

discussed below in the preamble and

cited in the regulatory text. If the State

or another member of the public, as

confirmed by the State, indicates in

comments that there is a site-specific,

State criterion that was approved by

EPA and continues to be an appropriate

value, EPA would amend the regulatory

text of the final rule such that the

otherwise applicable criteria would not

apply in that instance.

Sacramento River: EPA has approved

site-specific criteria for copper,

cadmium and zinc in the Sacramento

River, upstream of Hamilton City, in the
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Central Valley Region (RWQCB for the

Central Valley Region) of the State of

California. EPA approved these sitespecific criteria by letter dated August 7,

1985. Specifically, EPA approved for the

Sacramento River (and tributaries)

above Hamilton City, a copper criterion

of 5.6 μg/l (maximum), a zinc criterion

of 16 μg/l (maximum) and a cadmium

criterion of 0.22 μg/l (maximum), all in

the dissolved form using a hardness of

40 mg/l as CaCO3. (These criteria were

actually adopted by the State and

approved by EPA as equations which

vary with hardness.) These ‘‘maximum’’

criteria correspond to acute criteria in

today’s proposed rule. Therefore, federal

acute criteria for copper, cadmium, and

zinc for the Sacramento River (and

tributaries) above Hamilton City are not

necessary to protect the designated uses

and are not included in the proposed

rule. However, the EPA Administrator is

making a finding that it is necessary to

include chronic criteria for copper,

cadmium and zinc for the Sacramento

River (and tributaries) above Hamilton

City, as part of the proposed statewide

criteria in today’s proposed rule.

San Joaquin River: Site-specific

selenium criteria in portions of the San

Joaquin River, in the Central Valley

Region, are not included in this

proposed rule because they either have

been previously approved by EPA or

promulgated by EPA as part of the NTR.

EPA approved and disapproved Stateadopted site-specific selenium criteria

in portions of the San Joaquin River, in

the Central Valley Region of the State of

California (RWQCB for the Central

Valley Region). EPA’s determination on

these site-specific criteria is contained

in a letter dated April 13, 1990.

Specifically, EPA approved for the

San Joaquin River, mouth of Merced

River to Vernalis, an aquatic life

selenium criterion of 12 μg/l (maximum

with the understanding that the

instantaneous maximum concentration

may not exceed the objective more than

once every three years). Today’s

proposed rule does not affect this

federally-approved, State-adopted sitespecific acute criterion, and it remains

in effect for the San Joaquin River,

mouth of Merced River to Vernalis.

Therefore, an acute criterion for

selenium in the San Joaquin River,

mouth of Merced River to Vernalis is

not necessary to protect the designated

use and thus is not included in the

proposed rule.

By letter dated April 13, 1990, EPA

also approved for the San Joaquin River,

mouth of Merced River to Vernalis, a

State-adopted site-specific aquatic life

selenium criterion of 5 μg/l (monthly

mean); however, EPA disapproved a

State-adopted site-specific selenium

criterion of 8 μg/l (monthly mean—

critical year only) for these waters.

Subsequently, EPA promulgated a

chronic selenium criterion of 5 μg/l (4

day average) for waters of the San

Joaquin River from the mouth of the

Merced River to Vernalis in the NTR.

This chronic criterion applies to all

water quality programs concerning the

San Joaquin River, mouth of Merced

River to Vernalis. Today’s proposed rule

does not affect the federallypromulgated chronic selenium criterion

of 5 μg/l (4 day average) set forth in the

NTR. This previously federallypromulgated criterion remains in effect

for the San Joaquin River, mouth of

Merced River to Vernalis.

Grassland Water District, San Luis

National Wildlife Refuge, and Los Banos

State Wildlife Refuge: EPA approved for

the Grassland Water District, San Luis

National Wildlife Refuge, and Los Banos

State Wildlife Refuge, a State-adopted

site-specific aquatic life selenium

criterion of 2 μg/l (monthly mean) by

letter dated April 13, 1990. This

federally-approved, State-adopted sitespecific chronic criterion remains in

effect for the Grassland Water District,

San Luis National Wildlife Refuge and

Los Banos State Wildlife Refuge.

Therefore it is not necessary to include

in today’s proposed rule, a chronic

criterion for selenium for the Grassland

Water District, San Luis National

Wildlife Refuge and Los Banos State

Wildlife Refuge.

D. Rationale and Approach for

Developing the Proposed Rule

This section explains EPA’s legal

basis for today’s proposed rule, and

discusses EPA’s general approach for

developing the specific requirements for

the State of California.

In addition to Congressional directive,

there are a number of environmental

and programmatic reasons why

establishing water quality standards for

toxic pollutants in California is

important. Control of toxic pollutants in

surface waters is critical to the success

of a number of CWA programs and

objectives, including permitting, fish

tissue quality protection, coastal water

quality improvement, sediment

contamination control, certain nonpoint

source controls, pollution prevention

planning, and ecological protection.

1. Legal Basis

CWA section 303(c) specifies that

adoption of water quality standards is

primarily the responsibility of the states.

However, CWA section 303(c) also

describes a role for the federal

government to oversee state actions to

ensure compliance with CWA

requirements. If EPA’s review of the

states’ standards finds flaws or

omissions, then the CWA authorizes

EPA to correct the deficiencies (see

CWA section 303(c)(4)). This water

quality standards promulgation

authority has been used by EPA to issue

final rules on several separate occasions,

including the NTR, as amended, which

promulgated criteria similar to those

included here for a number of states.

These actions have addressed both

insufficiently protective state criteria

and/or designated uses and failure to

adopt needed criteria. Thus, today’s

action is not unique.

The CWA in section 303(c)(4)

provides two bases for promulgation of

federal water quality standards. The first

basis, in paragraph (A), applies when a

state submits new or revised standards

that EPA determines are not consistent

with the applicable requirements of the

CWA. If, after EPA’s disapproval, the

state does not amend its rules so as to

be consistent with the CWA, EPA is to

promptly propose appropriate federal

water quality standards for that state.

The second basis for an EPA action is

in paragraph (B), which provides that

EPA shall promptly initiate

promulgation ‘‘* * * in any case where

the Administrator determines that a

revised or new standard is necessary to

meet the requirements of this Act.’’ EPA

is using section 303(c)(4)(B) as the legal

basis for this proposed rule.

As stated in the preamble to the NTR,

the Administrator’s determination

under CWA section 303(c)(4) that

criteria are necessary to meet the

requirements of the Act could be

supported in several ways. EPA does

not believe that it is necessary to

support the criteria proposed today on

a pollutant-specific, water body-bywater-body basis. For EPA to undertake

an effort to conduct research and studies

of each stream segment or water body

across the State of California to

demonstrate that for each toxic

pollutant for which EPA has issued

CWA section 304(a) criteria guidance

there is a ‘‘discharge or presence’’ of

that pollutant which could reasonably

‘‘be expected to interfere with’’ the

designated use would impose an

enormous administrative burden and

would be contrary to the statutory

directive for swift action manifested by

the 1987 addition of section 303(c)(2)(B)

to the CWA.

Consistent with EPA’s approach in

the NTR, EPA interprets section

303(c)(2)(B) of the CWA to allow EPA to

act where the State has not succeeded

in establishing numeric water quality

standards for toxic pollutants. This
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42167

inaction can be the basis for the

Administrator’s determination under

section 303(c)(4) that new or revised

criteria are necessary to ensure

designated uses are protected. Here, this

determination is buttressed by the

evidence in the record for the rule of the

discharge or presence of priority toxic

pollutants in the State’s waters for

which the State does not have numeric

water quality criteria.

EPA’s interpretation of section

303(c)(2)(B) is supported by the

language of the provision, the statutory

framework and purpose of section 303,

and the legislative history. In adding

section 303(c)(2)(B) to the CWA,

Congress understood the existing

requirements in section 303(c)(1) for

triennial water quality standards review

and submissions and in section

303(c)(4)(B) for promulgation. CWA

section 303(c) includes numerous

deadlines and section 303(c)(4) directs

the Administrator to act ‘‘promptly’’

where the Administrator determines

that a revised or new standard is

necessary to meet the requirements of

the Act. Congress, by linking section

303(c)(2)(B) to the section 303(c)(1)

three-year review period, gave States a

last chance to correct this deficiency on

their own. The legislative history of the

provision demonstrates that chief

Senate sponsors, including Senators

Stafford, Chaffee and others wanted the

provision to eliminate State and EPA

delays and force quick action. Thus, to

interpret CWA section 303(c)(2)(B) and

(c)(4) to require such a cumbersome

pollutant specific effort on each stream

segment would essentially render

section 303(c)(2)(B) meaningless. The

provision and its legislative background

indicate that the Administrator’s

determination to invoke her section

303(c)(4)(B) authority can be met by a

generic finding of inaction by the State

without the need to develop pollutant

specific data for individual stream

segments.

This determination is supported by

information in the rulemaking record

showing the discharge or presence of

priority toxic pollutants throughout the

State. While this data is not necessarily

complete, it constitutes a strong record

supporting the need for numeric criteria

for priority toxic pollutants with section

304(a) criteria guidance where the State

does not have numeric criteria.

Today’s proposed rule would not

impose any undue or inappropriate

burden on the State of California or its

dischargers. It merely puts in place

numeric criteria for toxic pollutants that

are already utilized in other states in

implementing CWA programs. Under

this rulemaking, the State of California

retains the ability to adopt alternative

water quality criteria simply by

completing its criteria adoption process.

Upon EPA approval of those criteria,

EPA will initiate action to stay the

federally-promulgated criteria.

2. Approach for Developing the

Proposed Rule

In summary, EPA developed the

criteria proposed in today’s rule as

follows. Where EPA promulgated

criteria for California in the NTR, as

amended, EPA has not acted to amend

the criteria in the NTR, as amended.

Where criteria for California were not

included in the NTR, as amended, EPA

used section 304(a) national criteria

guidance documents as a basis for the

criteria proposed in this rule. EPA then

determined whether new information

since the development of the national

criteria guidance documents warranted

any changes. New information came

from two sources. For human health

criteria, new or revised risk reference

doses and cancer potency factors on

EPA’s Integrated Risk Information

System (IRIS) as of October 1996 form

the basis for criteria values different

from the national criteria guidance

documents. For aquatic life criteria,

updated data sets resulting in revised

criteria maximum concentrations

(CMCs) and criteria continuous

concentrations (CCCs) formed the basis

for differences from the national criteria

guidance documents. Both of these

types of changes are discussed in more

detail in the following section. This

revised information was used to develop

the water quality criteria proposed here

for the State of California.

E. Derivation of Criteria

1. Section 304(a) Criteria Guidance

Process

Under CWA section 304(a), EPA has

developed methodologies and specific

criteria guidance to protect aquatic life

and human health. These methodologies

are intended to provide protection for

all surface waters on a national basis.

The methodologies have been subject to

public review, as have the individual

criteria guidance documents.

Additionally, the methodologies have

been reviewed and approved by EPA’s

Science Advisory Board (SAB) of

external experts.

EPA has included in the record of this

rule the aquatic life methodology as

described in ‘‘Appendix B—Guidelines

for Deriving Water Quality Criteria for

the Protection of Aquatic Life and Its

Uses’’ to the ‘‘Water Quality Criteria

Documents; Availability’’ (45 FR 79341,

November 28, 1980) as amended by the

‘‘Summary of Revisions to Guidelines

for Deriving Numerical National Water

Quality Criteria for the Protection of

Aquatic Organisms and Their Uses’’ (50

FR 30792, July 29, 1985). (Note:

Throughout the remainder of this

preamble, this reference is described as

the 1985 Guidelines. Any page number

references are to the actual guidance

document, not the notice of availability

in the Federal Register. A copy of the

1985 Guidelines is available through the

National Technical Information Service

(PB85–227049), is in the administrative

record for this rule, and is abstracted in

Appendix A of Quality Criteria for

Water, 1986.) EPA has also included in

the administrative record of this rule the

human health methodology as described

in ‘‘Appendix C—Guidelines and

Methodology Used in the Preparation of

Health Effects Assessment Chapters of

the Consent Decree Water Criteria

Documents’’ (45 FR 79347, November

28, 1980). (Note: Throughout the

remainder of this preamble, this

reference is described as the Human

Health Guidelines or the 1980

Guidelines.) EPA also recommends that

the following be reviewed: ‘‘Appendix

D—Response to Comments on

Guidelines for Deriving Water Quality

Criteria for the Protection of Aquatic

Life and Its Uses,’’ (45 FR 79357,

November 28, 1980); ‘‘Appendix E—

Responses to Public Comments on the

Human Health Effects Methodology for

Deriving Ambient Water Quality

Criteria’’ (45 FR 79368, November 28,

1980); and ‘‘Appendix B—Response to

Comments on Guidelines for Deriving

Numerical National Water Quality

Criteria for the Protection of Aquatic

Organisms and Their Uses’’ (50 FR

30793, July 29, 1985). EPA placed into

the administrative record for this

rulemaking the most current individual

criteria guidance for the priority toxic

pollutants included in today’s rule.

(Note: All references to appendices are

to the associated Federal Register

publication.)

2. Aquatic Life Criteria

Aquatic life criteria may be expressed

in numeric or narrative form. EPA’s

1985 Guidelines describe an objective,

internally consistent and appropriate

way of deriving chemical-specific,

numeric water quality criteria for the

protection of the presence of, as well as

the uses of, both fresh and marine water

aquatic organisms.

An aquatic life criterion derived using

EPA’s CWA section 304(a) method

‘‘might be thought of as an estimate of

the highest concentration of a substance

in water which does not present a

significant risk to the aquatic organisms
42168 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

in the water and their uses.’’ (45 FR

79341.) The term ‘‘their uses’’ refers to

consumption by humans and wildlife

(1985 Guidelines, page 48). EPA’s

guidelines are designed to derive

criteria that protect aquatic

communities by protecting most of the

species and their uses most of the time,

but not necessarily all of the species all

of the time (1985 Guidelines, page 1).

EPA’s 1985 Guidelines attempt to

provide a reasonable and adequate

amount of protection with only a small

possibility of substantial overprotection

or underprotection. As discussed in

detail below, there are several

individual factors which may make the

criteria somewhat overprotective or

underprotective. The approach EPA is

using is believed to be as well balanced

as possible, given the state of the

science.

Numerical aquatic life criteria derived

using EPA’s 1985 Guidelines are

expressed as short-term and long-term

numbers, rather than one number, in

order that the criteria more accurately

reflect toxicological and practical

realities. The combination of a criteria

maximum concentration (CMC), a shortterm concentration acute limit, and a

criteria continuous concentration (CCC),

a four-day average concentration

chronic limit, provide protection of

aquatic life and its uses from acute and

chronic toxicity to animals and plants,

and from bioconcentration by aquatic

organisms, without being as restrictive

as a one-number criterion would have to

be. (1985 Guidelines, pages 4, 5.) The

terms CMC and CCC are the

scientifically correct names for the two

(acute and chronic) values of a criterion

for a pollutant; however, this document

will also refer to acute criterion and

chronic criterion to which they are more

commonly referred.

The two-number criteria are intended

to identify average pollutant

concentrations which will produce

water quality generally suited to

maintenance of aquatic life and their

uses while restricting the duration of

excursions over the average so that total

exposures will not cause unacceptable

adverse effects. Merely specifying an

average value over a time period is

insufficient unless the time period is

short, because excursions higher than

the average can kill or cause substantial

damage in short periods.

A minimum data set of eight specified

families is required for criteria

development (details are given in the

1985 Guidelines, page 22). The eight

specific families are intended to be

representative of a wide spectrum of

aquatic life. For this reason it is not

necessary that the specific organisms

tested be actually present in the water

body. States may develop site-specific

criteria using native species, provided

that the broad spectrum represented by

the eight families is maintained. All

aquatic organisms and their common

uses are meant to be considered, but not

necessarily protected, if relevant data

are available.

EPA’s application of guidelines to

develop the criteria matrix in the

proposed rule is judged by the Agency

to be applicable to all waters of the

United States, and to all ecosystems

(1985 Guidelines, page 4). There are

waters and ecosystems where sitespecific criteria could be developed, as

discussed below, but the State should

identify those waters and develop the

appropriate site-specific criteria.

Fresh water and salt water (including

both estuarine and marine waters) have

different chemical compositions, and

freshwater and saltwater species rarely

inhabit the same water simultaneously.

To provide additional accuracy, criteria

are developed for fresh water and for

salt water.

Limitations of the analyses which

may make the criteria underprotective

include the fact that data for all species

are not available and therefore not

considered; the analysis also applies to

criteria on an individual basis with no

consideration of additive or synergistic

effects, and the analysis does not

consider impacts on wildlife, due

principally to a lack of data. Chemical

toxicity is often related to certain

receiving water characteristics (pH,

hardness, etc.) of a water body.

Adoption of some criteria without

consideration of these parameters could

result in the criteria being

overprotective.

a. Freshwater Criteria

For this proposal, EPA updated

freshwater aquatic life criteria contained

in CWA section 304(a) criteria guidance

first published in the early 1980’s and

later modified in the NTR, as amended,

for the following eleven pollutants:

arsenic, cadmium, chromium (VI),

copper, mercury, dieldrin, endrin,

lindane (gamma BHC), nickel,

pentachlorophenol, and zinc. These

updates are explained in a technical

support document entitled, 1995

Updates: Water Quality Criteria

Documents for the Protection of Aquatic

Life in Ambient Water, (U.S. EPA–820–

B–96–001, September 1996), available

in the administrative record to this

rulemaking; this document presents the

derivation of each of the final CMCs and

CCCs and the toxicity studies from

which the updated freshwater criteria

for the eleven pollutants were derived.

The presentation of polychlorinated

biphenyls (PCB) criteria in the criteria

matrix for this proposal differs from that

in the NTR, as amended; for this

proposal, the criteria are expressed as a

total of all aroclors, while for the NTR,

as amended, the criteria are expressed

for each aroclor. The mercury criteria

also differ in this proposal due to the

Agency’s movement away from aquatic

life criteria based on the Final Residue

Value (FRV) procedure of the 1985

Guidance. Differences between the

eleven CMCs and CCCs as contained in

CWA section 304(a) criteria guidance

documents and the CMCs and CCCs in

this proposed rule can be attributed to

one or more of the following reasons.

First, EPA derived and published

CWA section 304(a) criteria guidance

documents between 1980 and 1987.

Some of the aquatic life criteria in this

proposed rule were calculated using

data published subsequent to the

issuance of individual 304(a) criteria

guidance documents or using other new

information. The pollutants for which

this applies are: arsenic, cadmium,

chromium (VI), copper, mercury,

dieldrin, endrin, lindane, nickel,

pentachlorophenol, and zinc. The use of

an updated database resulted in less

restrictive acute and/or chronic criteria

for cadmium and zinc as compared to

the published criteria guidance

documents. EPA believes that the

differences between the proposed

updated criteria and the national

published criteria guidance documents

are insignificant. However, EPA believes

that it is appropriate to propose criteria

in this rule based on the most recent

data. The following table shows the

differences between the proposed

criteria for this rule and the 304(a)

criteria guidance which were

promulgated in the NTR, as amended.

All values are in micrograms per liter or

μg/l:

Compound

Proposed freshwater NTR freshwater

CMC CCC CMC CCC

Arsenic ...................................................................................................................... 1,2 340 1,2 150 1,3 360 1,3 190
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42169

Compound

Proposed freshwater NTR freshwater

CMC CCC CMC CCC

Cadmium .................................................................................................................. 1,2,4 4.3 1,2,4 2.2 1,5 3.7 1,5 1.0

Chromium (VI) .......................................................................................................... 1,2 16 1,2 11 1,3 15 1,3 10

Copper ...................................................................................................................... 1,2,4 13 1,2,4 9.0 1,5 17 1,5 11

Nickel ........................................................................................................................ 1,2,4 470 1,2,4 52 1,5 1400 1,5 160

Zinc ........................................................................................................................... 1,2,4 120 1,2,4 120 1,5 110 1,5 100

Pentachloro-phenol ................................................................................................... 2,6 19 2,6 15 6 20 6 13

Lindane (gamma-BHC) ............................................................................................. 2 0.95 ...................... 7 2 0.08

Dieldrin ...................................................................................................................... 2 0.24 2 0.056 7 2.5 0.0019

Endrin ....................................................................................................................... 2 0.086 2 0.036 7 0.18 0.0023

Mercury ..................................................................................................................... 1,2,3 1.4 1,2,3 0.77 1,3 2.1 0.012

PCBs ......................................................................................................................... ...................... 8,9 0.014 ...................... 8,10 0.014

Mercury ..................................................................................................................... 1,3 1.8 1,3 0.94 1,3 1.8 0.025

PCBs ......................................................................................................................... ...................... 8,9 0.03 ...................... 8,10 0.03

1These freshwater and saltwater criteria for metals are expressed in terms of the dissolved fraction of the metal in the water column, not the

total recoverable fraction. Criterion values were calculated by using EPA’s CWA 304(a) criteria guidance values (described in the total recoverable fraction) and then applying conversion factors as in the NTR, as amended, (60 FR 22228, May 4, 1995 and 40 CFR part 131). 2This criterion has been recalculated pursuant to 1995 Updates: Water Quality Criteria Documents for the Protection of Aquatic Life in Ambient

Water (EPA–820–B–96–001, September 1996). See also the Great Lakes Water Quality Initiative (40 CFR Parts 9, 122, 123, 131, and 132; Final

Water Quality Guidance for the Great Lakes System, Final Rule; 60 FR 15366, March 23, 1995) and Great Lakes Water Quality Initiative Criteria

Documents for the Protection of Aquatic Life in Ambient Water (EPA–820–B–95–004, March 1995). 3 Criteria for these metals are expressed as a function of the water-effect ratio (WER) as defined in 40 CFR 131.36(c).

4These freshwater aquatic life criteria for metals are expressed as a function of total hardness (mg/l as CaCO3 ) in the water body. The equations are provided in the proposed rule at 40 CFR 131.38(b)(2). Values displayed above and in the proposed rule matrix correspond to a total

hardness of 100 mg/l as CaCO3. 5Freshwater aquatic life criteria for these metals are expressed as a function of total hardness (mg/l as CaCO3), and as a function of the pollutant’s water-effect ratio, WER, as defined in 40 CFR 131.36(c). The equations are provided in the NTR, as amended, and values above and in

the rule matrix correspond to a total hardness of 100 mg/l as CaCO3 and a water-effect ratio of 1.0. 6These freshwater aquatic life criteria for pentachlorophenol are expressed as a function of pH, and are calculated as follows: (Values displayed above in the matrix correspond to a pH of 7.8.) CMC=exp(1.005 (pH)–4.830). CCC=exp(1.005(pH)–5.290). 7These aquatic life criteria for these pollutants were issued in 1980 utilizing the 1980 Guidelines for criteria development. The acute values

shown are final acute values (FAV) which by the 1980 Guidelines are instantaneous values. 8The CAS numbers for the PCB compounds are 53469219, 11097691, 11104282, 11141165, 12672296, 11096825, and 12674112, respectively. 9This proposed criterion is the sum of all aroclors.

10This criterion was listed for each aroclor in the matrix at 40 CFR 131.36(b)(1).

Secondly, some of the 304(a) criteria

guidance documents were derived using

a methodology which preceded EPA’s

current methodology, the 1985

Guidelines (pages 16 and 17).

In this proposed rule, where sufficient

data existed to use the 1985 Guidelines,

EPA recalculated the criteria. The

chemicals for which this applies are:

dieldrin, endrin, and lindane (gamma

BHC) (chronic criterion only). The NTR,

as amended, however, did not update

the 1980 criteria using the 1985

Guidelines.

Third, EPA has deleted some of the

data used in deriving three criteria:

specifically, the 1984 criterion for

copper and the 1980 criteria for dieldrin

and endrin, because under EPA’s 1985

Guidelines, the toxicity testing

procedure was unacceptable.

Fourth, in several of the 304(a) criteria

guidance documents, the range of

Species Mean Acute Values (SMAVs) or

Species Mean Chronic Values (SMCVs)

was greater than a factor of five for some

genera. Because of this wide range, EPA

set the Genus Mean Acute Values

(GMAVs) or Genus Mean Chronic

Values (GMCVs) for those genera equal

to the lowest SMAV or SMCV for that

genus in order to provide adequate

protection to all tested species in the

genus. The pollutants for which this

applies are cadmium, copper and

dieldrin.

In addition to the reasons cited earlier

concerning differences between NTR, as

amended, criteria and proposed CMCs

for this rulemaking, several of the

proposed CCCs are affected by a

preference of using freshwater AcuteChronic Ratios (ACRs). In some of the

304(a) criteria guidance documents,

EPA had used saltwater ACRs in the

calculation of freshwater Final Chronic

Values (FCVs) when available. In

updating criteria, EPA generally did not

use saltwater ACRs when there were a

sufficient number of acceptable

freshwater ACRs to calculate a Final

Acute-Chronic Ratio (FACR) because

freshwater data is preferable for

freshwater criteria. When there was an

insufficient number of freshwater ACRs

to calculate a FACR, EPA used saltwater

ACRs with any acceptable freshwater

ACRs. The pollutants for which this

applies are: dieldrin, endrin and nickel.

Removal of saltwater ACRs from the

data sets had a minor effect on the

resultant criteria.

Today’s rule utilizes the Final

Residue Value (FRV) procedure of the

1985 Guidelines for PCBs. The 1985

national methodology in the 1985

Guidelines indicates that the FRV is

intended to prevent concentrations of

pollutants in commercial or recreational

aquatic species from affecting the

marketability of those species or

affecting wildlife that consume aquatic

life. While in today’s rule the FRV is

used to calculate the chronic values for

PCBs, EPA believes it may not be as

protective as criteria derived from the

Final Chronic Value (FCV). However,

the use of the FRV in deriving the

chronic values for PCBs represents

EPA’s best available scientific approach.

The NTR, as amended, criteria for

dieldrin, endrin, and mercury were

based on FRVs calculated from FDA

action levels. EPA now believes that the

human health criteria proposed

elsewhere in this notice will provide an

appropriate level of protection to

humans consuming freshwater fish and

shellfish, but that use of the FDA action

levels to protect aquatic life (fish and

propagation of fish) is inappropriate. In

this rule, EPA updated the chronic

values for dieldrin, endrin and mercury

based on Final Chronic Values (FCVs)

calculated by dividing a Final Acute

Value (FAV) by the Final Acute-Chronic

Ratio (FACR).

The derivation of each of these

criteria, and the toxicity studies upon
42170 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

which they are based, are discussed in

a technical support document entitled,

1995 Updates: Water Quality Criteria

Documents for the Protection of Aquatic

Life in Ambient Water (EPA–820–B–96–

001, September 1996). This document is

available in the administrative record

for this rulemaking.

b. Freshwater Acute Selenium Criterion

EPA is proposing a different

freshwater acute aquatic life criterion

for selenium in this proposed rule than

was promulgated in the NTR, as

amended. EPA’s proposal here is

consistent with EPA’s recent (proposed)

selenium criterion maximum

concentration for the Water Quality

Guidance for the Great Lakes System (61

FR 58444, November 14, 1996). This

proposal takes into account data

showing that selenium’s two most

prevalent oxidation states, selenite and

selenate, present differing potentials for

aquatic toxicity, as well as new data

indicating that various forms of

selenium are additive. Additivity

increases the toxicity of mixtures of

different forms of the pollutant. The

new approach produces a different

selenium acute criterion concentration,

or CMC, depending upon the relative

proportions of selenite, selenate, and

other forms of selenium that are present.

While these revisions may produce

either a less or a more stringent acute

criterion for selenium, depending on

which form of the pollutant is

predominant in a water body, the

proposed freshwater acute criterion will

protect aquatic life in fresh waters of the

State of California.

Derivation of the Current Freshwater

Criterion for Selenium: When EPA

published a recommended freshwater

aquatic life criterion for selenium in

1987, it considered both field data on

chronic toxicity from Belews Lake in

North Carolina and laboratory data

showing chronic effects. A comparison

of the data indicated that selenium was

more toxic to aquatic life in the field

than in standard laboratory toxicity

tests. Consequently, to ensure that the

criterion would protect aquatic life, EPA

derived a chronic criterion, or a CCC, of

5 μg/l for total recoverable selenium

from the field data. Because the Belews

Lake study did not distinguish between

selenite, selenate, and any other form of

selenium, and because some forms of

selenium can convert to other forms

over time (U.S. EPA, 1987), EPA

established a single CCC for selenium

rather than a separate CCC for selenite

and/or selenate.

EPA reasoned that acute effects would

also be more severe in the field than in

the laboratory. EPA, however, was not

able to find any field studies assessing

acute effects. Consequently, EPA backcalculated the CMC from the fieldderived CCC for total selenium, arriving

at a value of 19.98 μg/l, which it

rounded to 20 μg/l. When EPA proposed

and promulgated selenium criteria for

the NTR, as amended, it used the same

field-data approach and calculated a

CMC of 20 μg/l and a CCC of 5 μg/l for

all forms of selenium.

EPA noted that, had it concluded that

laboratory data could serve as a basis for

the selenium criteria, there were

sufficient laboratory studies on acute

effects to establish separate CMCs for

both selenate and selenite. EPA

calculated that a CMC for selenite

(selenium IV) based on laboratory data

might have been 185.9 μg/l, while a

CMC for selenate (selenium VI) might

have been 12.82 μg/l. As explained

above, however, EPA chose to base the

CMC on field data that did not

differentiate between selenite and

selenate.

EPA is proposing a different approach

to that used in the NTR, amended, for

the fresh waters of California covered by

this proposed rule. EPA is proposing a

new CMC for total selenium based on

more recent studies which indicate that

the toxicities of various forms of

selenium are additive. EPA is proposing

an equation that will allow calculation

of a CMC for selenium based on the

relative proportions of selenite, selenate

and other selenium forms present in a

specific water body. The toxicities for

selenite and selenate used in this

equation are based on the laboratory

studies cited in the 1987 and 1995

selenium criteria documents, and are

identical to the values calculated in

those documents.

EPA continues to believe that the field

data support a CCC of 5 μg/l for

selenium. The chronic criterion

addresses longer-term exposures to

selenium under field conditions,

including exposure through the food

chain. EPA has no field data that can

support different chronic criteria for

different forms of selenium.

Furthermore, EPA believes that current

studies show that the various forms of

selenium ‘‘interconvert’’ to other forms

over these longer time frames, so that

the relative proportions of the different

forms change during the exposure

period. A form that exhibits low toxicity

at one point during the exposure period

may convert to a different, more toxic

form at a different point.

Selenium Chemistry: Selenium takes

several forms in ambient waters which

can significantly alter its toxicity to

aquatic life, as shown below. Inorganic

selenium has two oxidation states (i.e.,

selenium IV, or selenite, and selenium

VI, or selenate), which can exist

simultaneously in aerobic surface water

at pH 6.5 to 9.0. Chemical conversion

from one oxidation state to another

often proceeds at such a slow rate in

aerobic surface water that

thermodynamic considerations do not

determine the relative concentrations of

the oxidation states. Although selenate

(selenium VI) is thermodynamically

favored in oxygenated alkaline water,

substantial concentrations of both

organoselenium (selenium minus II) and

selenite (selenium IV) are not

uncommon (Burton et al. 1980; Cutter

and Bruland 1984; Measures and Burton

1978; North Carolina Department of

Natural Resources and Community

Development 1986; Robberecht and Van

Gricken 1982; Takayanagi and Cossa

1985; Takayanagi and Wong 1984a,b:

Uchida et al. 1980).

Various forms of organic selenium

also occur in water (Besser et al. 1994;

Cutter 1991). Toxicity data for some

organic selenium forms are available

and are compared below to toxicity data

for selenite and selenate:
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42171

Compound Zebrafish a

(mg/l)

C. riparius b, c, d

(mg/l)

Daphnia

magnae e

(mg/l)

Selenate .................................................................................................................................................. 18. 16.2 10.5 2.84

Seleno-DL-cystine .................................................................................................................................. 12 .............................. 2.01

Selenite ................................................................................................................................................... 1. 7.95 14.6 0.55

Seleno-DL-methionine ............................................................................................................................ 0.1 .............................. 0.31

Seleno-L-methionine ............................................................................................................................... ................ 5.78 6.88 ..............

a 10-day LC50 (Niimi and LaHam 1976). d 48-hr LC50 (Maier et al. 1993). b 48-hr LC50 (Ingersoll et al. 1990). e 48-hr LC50 (Maier et al. 1993). c River Water.

Cutter (1991) described methods for

measuring total recoverable and

dissolved selenate, selenite,

organoselenium, and selenium in water,

and other information concerning the

measurement of selenium in water has

been published by Besser et al. (1994),

McKeown and Marinas (1986), Pitts et

al. (1994), and Takayanagi and Cosa

(1985).

EPA believes that recent studies

demonstrate the acute toxicities of

selenate, selenite, and one form of

organoselenium are additive; that is,

these forms are more toxic together then

they are separately (Hamilton and Buhl

1990; Maier et al. 1993). The studies

demonstrated additivity by comparing

the toxicities of mixtures to the

toxicities of the separate toxicants.

Thus, EPA believes that it would be

appropriate to establish separate CMCs

for selenate and selenite only in

situations in which either selenate or

selenite is the only form of selenium in

the water column. When more than one

form occurs in the water, additivity

should be taken into account so that the

CMC for selenium is a function of the

toxicities and concentrations of the

forms. EPA is proposing an equation

that can be used to derive an

appropriate criterion for total selenium

based on the relative concentrations of

selenite, selenate, and all other forms of

selenium found in a particular water

body.

Toxicity of Three Categories of

Selenium: Selenium (IV). EPA is

proposing to rely on the laboratory data

contained in the 1987 and 1995 criteria

documents to establish an acute toxicity

of 185.9 μg/l for selenite.

Selenium (VI). EPA is proposing to

rely on the laboratory data contained in

the 1987 and 1995 criteria documents to

establish an acute toxicity of 12.83

μg/l for selenate.

Other Forms of Selenium. EPA has

not found and believes that sufficient

toxicity data do not exist to allow

derivation of CMCs for other selenium

compounds. Nevertheless, as indicated

in the previous table, the acute toxicity

of such other forms of selenium appears

to be significant with toxicity increasing

by as much as 180 times depending on

the form of selenium and the test

organism. Toxicity tests conducted on

the other forms of selenium indicate

that they can be more toxic than

selenate and selenite. Consequently, in

order not to ignore the toxicity of these

other forms of selenium, EPA is

proposing to assume that half of the

measured or derived concentration of

‘‘other’’ selenium forms is as toxic as

selenate and half is as toxic as selenite.

EPA believes this default assumption is

more reasonable than assuming either

that the entire quantity of ‘‘other’’ forms

is as toxic as either selenate or selenite,

or that it is not toxic. Such assumptions

would be more likely to over-predict or

under-predict the toxicity of this ‘‘other

forms’’ category. EPA is also reluctant to

compute any type of ‘‘average’’ from the

toxicity data on ‘‘other forms’’ presented

in the table above. These data are quite

sparse. Moreover, they reflect only

organic selenium forms, and the

toxicities of other inorganic forms and

compounds may be quite different.

Equation: Additive toxicity means

that the concentrations of the different

forms should be added together after

adjusting for the relative toxicity of

each. For a single toxicant the goal is for

the concentration, c, to be less than or

equal to the criterion, CMC; that is, the

ratio c/CMC ≤ 1. For additive toxicants

the goal is for the sum of such ratios to

be less than or equal to 1. Thus, for two

forms of selenium with additive acute

toxicities, the concentration of each

form should be controlled such that:

C

CMC

C

CMC

1

1

2

2

+ ≤ 1

where c1 is the concentration of

selenite and other selenium assumed to

have the toxicity of selenite, c2 is the

concentration and selenate and other

selenium assumed to have the toxicity

of selenate; and CMC1 and CMC2 are the

CMCs for selenite and selenate

respectively. A Criterion Maximum

Concentration, CMCSe, for the combined

additive forms of selenium can then be

calculated from the following equation,

which is derived from the previous one:

CMC f

CMC

f

CMC

Se =

+

1

1

1

2

2

where f1 and f2 are the fractions of total

selenium that are treated as selenite

and selenate respectively (that is,

f1=c1/cSe and cSe=c1+c2), and

f1+f2=1.

The above equations, when coupled

with the assumption that half of the

other selenium (including

organoselenium) has the toxicity of

selenite and half has the toxicity of

selenate, behave as follows. If the

concentrations of selenite and other

selenium are zero (c1=0) then the

Criterion Maximum Concentration

(CMCSe) would be calculated to be 12.82

μg/l, the CMC of selenate. On the other

hand, if the concentrations of selenate

and other selenium are zero, then

CMCSe would be calculated to be 185.9

μg/l, the CMC of selenite. In

determining compliance with this

criterion, EPA expects that monitoring

to determine speciation will be

necessary.

EPA is requesting comment on the

data and approach for deriving the

proposed CMC for selenium applicable

to California in this rulemaking.

Specifically, EPA is requesting comment

on the scientific basis for establishing

the additivity of the toxicities of the

various forms of selenium (selenate,

selenite, and other selenium

compounds). EPA also requests

comments on the procedure used to

account for the additivity of the various

forms of selenium in the criterion

derivation algorithm. If persons have

filed comments on the November 1996

notice, cited above, that they wish to

submit for this rulemaking, they should

submit them as described above.

c. Dissolved Metals Criteria

In December of 1992, in the NTR, EPA

promulgated water quality criteria for

several states that had failed to meet the

requirements of CWA section

303(c)(2)(B). Included among the water

quality criteria promulgated were

numeric criteria for the protection of

aquatic life for 11 metals: arsenic,
42172 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

cadmium, chromium (III), chromium

(VI), copper, lead, mercury, nickel,

selenium, silver and zinc. Criteria for

two metals applied to the State of

California: chromium III and selenium.

The Agency received extensive public

comment during the development of the

NTR regarding the most appropriate

approach for expressing the metals

criteria. The principal issue was the

correlation between metals that are

measured and metals that are

bioavailable and toxic to aquatic life.

At the time of the NTR promulgation,

Agency policy was to express metals

criteria, as recommended in the section

304(a) criteria guidance documents, as

total recoverable metal measurements.

Agency guidance prior to the NTR

promulgation indicated that metals

criteria may be expressed either as total

recoverable metal or dissolved metal.

See Interim Guidance on Interpretation

and Implementation of Aquatic Life

Criteria for Metals, U.S. EPA, May 1992

(notice of availability published at 57

FR 4041, June 5, 1992). Since the NTR

covered a substantial number of water

bodies of varying water quality, EPA

selected what it considered a simple,

conservative approach to implement the

metals criteria, namely, the total

recoverable method.

EPA continued to work with the states

and other interested parties on the issue

of metals bioavailability and toxicity.

EPA held a workshop of invited experts

on the issue and as a result of the

consultations, the Agency issued a

policy memorandum on October 1,

1993, entitled, Office of Water Policy

and Technical Guidance on

Interpretation and Implementation of

Aquatic Life Metals Criteria (the Metals

Policy). The Metals Policy states:

It is now the policy of the Office of Water

that the use of dissolved metal to set and

measure compliance with water quality

standards is the recommended approach,

because dissolved metal more closely

approximates the bioavailable fraction of the

metal in the water column than does total

recoverable metal.

It further states:

Until the scientific uncertainties are better

resolved, a range of different risk

management decisions can be justified. EPA

recommends that State water quality

standards be based on dissolved metal. EPA

will also approve a State risk management

decision to adopt standards based on total

recoverable metal, if those standards are

otherwise approvable as a matter of law.

The adoption of the Metals Policy did

not change EPA’s position that the

existing total recoverable criteria

published under section 304(a) of the

CWA were scientifically defensible.

EPA believed, and continues to believe,

that when a state develops and adopts

its standards, the state, in making its

risk management decision, may want to

consider sediment, food chain effects,

and other fate-related issues and decide

to adopt total recoverable or dissolved

metals criteria.

In 1993, a number of parties brought

lawsuits challenging the NTR metals

criteria. See American Forest and Paper

Ass’n, Inc. et al. v. U.S. EPA

(Consolidated Case No. 93–0694 (RMU),

D.D.C.). The plaintiffs in those lawsuits

wanted the permitting authorities in the

NTR states to use criteria based on

dissolved metal rather than total

recoverable metal. After careful

consideration, EPA concluded that it

was in the public interest to revise the

metals criteria promulgated in the NTR

to reflect the Office of Water’s new

metals policy. On February 15, 1995,

EPA and the plaintiffs filed a partial

settlement agreement with the Court.

Pursuant to the terms of the agreement,

EPA agreed to issue an administrative

stay of the numeric aquatic life water

quality criteria (expressed as total

recoverable metal) for: arsenic;

cadmium, chromium (III); chromium

(VI); copper; lead, mercury (acute only),

nickel, selenium (saltwater only), silver,

and zinc. The stay was effective April

14, 1995 (60 FR 22228, May 4, 1995),

and was only intended to be in effect

until EPA took action to amend the NTR

by promulgating new metals criteria

based on dissolved metal. EPA

published an interim final amendment

to the NTR effective April 15, 1995; this

amendment promulgated new metals

criteria for the metals listed in the stay

(60 FR 22229, May 4, 1995).

The numeric criteria in the NTR, as

amended, reflect the Office of Water’s

current policy with respect to metals.

The 1995 NTR amendment promulgated

dissolved metals criteria as substitutes

for the total recoverable metals criteria

subject to the EPA’s administrative stay.

The NTR promulgated freshwater

chromium (III) criteria and freshwater

selenium criteria for the State of

California. However, since the

amendments did not change the

freshwater selenium criteria, only

California’s chromium (III) criteria were

changed to the dissolved form through

the NTR, as amended.

Since EPA’s previous criteria

guidance had been expressed as total

recoverable metal, to express the criteria

as dissolved, conversion factors were

developed to account for the possible

presence of particulate metal in the

laboratory toxicity tests used to develop

the total recoverable criteria. Initially,

EPA included a set of recommended

freshwater conversion factors with the

Metals Policy. Based on additional

laboratory evaluations that simulated

the original toxicity tests, EPA refined

the procedures used to develop

freshwater conversion factors for aquatic

life criteria. These new conversion

factors were made available for public

review and comment in the

amendments to the NTR on May 4,

1995, at 60 FR 22229.

EPA also conducted saltwater

laboratory simulation tests for the

development of conversion factors for

saltwater metals criteria. The saltwater

tests results were first available in the

amendments to the NTR on May 4,

1995. The conversion factors in this

proposed rule and other technical

reports are the same as those referenced

in the May 4, 1995 amendments to the

NTR and supersede the conversion

factors in Attachment 2 of the Metals

Policy.

Freshwater Criteria Conversion

Factors: The freshwater conversion

factors contained in today’s proposed

rule are contained in the Derivation of

Conversion Factors for the Calculation

of Dissolved Freshwater Aquatic Life

Criteria for Metals, U.S. EPA, 1995,

available in the administrative record

for this rulemaking. This study did not

include laboratory simulation tests for

mercury or silver; therefore, the

freshwater conversion factors for

mercury and silver used today are from

the Metals Policy, also in the record for

this rule. These conversion factors are

presented in 40 CFR 131.38(b)(2) of

today’s proposed rule.

The conversion factors for most

freshwater metals were established as

constant values. For cadmium and lead

however, EPA found that water

hardness mediated the conversion factor

and should be taken into account when

converting total recoverable cadmium

and lead criteria to dissolved. 40 CFR

131.38(b)(2) of today’s proposed rule

presents the hardness-dependent

conversion factors for cadmium and

lead.

Saltwater Criteria Conversion Factors:

Acute saltwater conversion factors were

first promulgated in the amendments to

the NTR, and are again being proposed

in this rule. The data and the acute

criteria conversion factors for salt water

are contained in the Derivation of

Conversion Factors for the Calculation

of Dissolved Saltwater Aquatic Life

Criteria for Metals, U.S. EPA, 1995. This

summary report and its supporting data

are available in the administrative

record. Saltwater chronic conversion

factors have not been developed

separately and therefore are not

available in today’s proposed rule.

Based on close similarities between the
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42173

freshwater acute and chronic conversion

factors, EPA believes that, if calculated,

the chronic saltwater conversion factors

would be nearly the same as the acute

saltwater factors. In the absence of these

chronic conversion factors, the saltwater

acute conversion factors would apply.

Salt water simulation tests were not

completed for mercury or silver,

therefore, the conversion factors from

the Metals Policy continue to apply. The

saltwater conversion factors are

presented in 40 CFR 131.38(b)(2) of

today’s proposed rule.

Calculation of Dissolved Metals

Criteria: Metals criteria values in today’s

proposed rule in the matrix at

131.38(b)(1) are shown as dissolved

metal. These criteria have been

calculated in one of two ways. For

freshwater metals criteria that are

hardness-dependent, the dissolved

metal criteria value is calculated

separately for each hardness using the

table at proposed 40 CFR 131.38(b)(2).

The hardness-dependent freshwater

values presented in the matrix at

proposed 40 CFR 131.38(b)(1) have been

calculated using a hardness of 100 mg/

l as CaCO3 for illustrative purposes

only. Saltwater and freshwater metals

criteria that are not hardness-dependent

are calculated by taking the total

recoverable criteria values (from EPA’s

national section 304(a) criteria guidance

documents, as updated as described in

section a. above) before rounding, and

multiplying them by the appropriate

conversion factors. The final dissolved

metals criteria values, as they appear in

the matrix at proposed 40 CFR

131.38(b)(1), are rounded to two

significant figures.

Translators for Dissolved to Total

Recoverable Metals Limits: EPA’s

National Pollutant Discharge

Elimination System (NPDES)

regulations require that limits for metals

in permits be stated as total recoverable

in most cases (see 40 CFR 122.45(c))

except when an effluent guideline

specifies the limitation in another form

of the metal, the approved analytical

methods measure only dissolved metal,

or the permit writer expresses a metal’s

limit in another form (e.g., dissolved,

specific valence, or total) when required

to carry out provisions of the CWA. This

is because the chemical conditions in

ambient waters frequently differ

substantially from those in the effluent

and there is no assurance that effluent

particulate metals would not dissolve

after discharge. The NPDES permit

regulations do not require that water

quality standards be expressed as total

recoverable; rather, the regulations

require permit writers to develop permit

limits that are expressed in terms of

metals concentrations and loadings that

are measured using the total recoverable

method. Expressing criteria as dissolved

metal requires translation between

different metal forms in the calculation

of the permit limit so that a total

recoverable permit limit can be

established that will achieve water

quality standards. Thus, it is important

that permitting authorities and other

authorities have the ability to translate

between dissolved metal in ambient

waters and total recoverable metal in

effluent.

EPA has completed guidance on the

use of translators to convert from

dissolved metals criteria to total

recoverable permit limits. The

document, The Metals Translator:

Guidance for Calculating a Total

Recoverable Permit Limit From a

Dissolved Criterion (EPA 823–B–96–

007, June 1996), is included in the

administrative record for today’s

proposed rule. This technical guidance

examines how to develop a metals

translator which is defined as the

fraction of total recoverable metal in the

downstream water that is dissolved, i.e.,

the dissolved metal concentration

divided by the total recoverable metal

concentration. A translator may take one

of three forms: (1) It may be assumed to

be equivalent to the criteria guidance

conversion factors; (2) it may be

developed directly as the ratio of

dissolved to total recoverable metal; and

(3) it may be developed through the use

of a partition coefficient that is

functionally related to the number of

metal binding sites on the adsorbent in

the water column (e.g., concentrations

of total suspended solids or TSS). This

guidance document discusses these

three forms of translators, as well as

field study designs, data generation and

analysis, and site-specific study plans to

generate site-specific translators.

California Regional Water Quality

Control Boards may use any of these

methods in developing water qualitybased permit limits to meet dissolved

metals criteria. EPA encourages the

State to adopt a statewide policy on the

use of translators so that the most

appropriate method or methods are used

consistently within California.

d. Application of Metals Criteria

In selecting an approach for

implementing the metals criteria, the

principal issue is the correlation

between metals that are measured and

metals that are biologically available

and toxic. In order to assure that the

metals criteria are appropriate for the

chemical conditions under which they

are applied, EPA is providing for the

adjustment of the criteria through

application of the ‘‘water-effect ratio’’

procedure. EPA notes that performing

the testing to use a site-specific watereffect ratio is optional on the part of the

State.

In the NTR, as amended, EPA

identified the water-effect ratio (WER)

procedure as a method for optional sitespecific criteria development for certain

metals. The WER approach compares

bioavailability and toxicity of a specific

pollutant in receiving waters and in

laboratory waters. A WER is an

appropriate measure of the toxicity of a

material obtained in a site water divided

by the same measure of the toxicity of

the same material obtained

simultaneously in a laboratory dilution

water.

On February 22, 1994, EPA issued

Interim Guidance on the Determination

and Use of the Water-Effect Ratios for

Metals (EPA 823–B–94–001) now

incorporated into the updated Second

Edition of the Water Quality Standards

Handbook, Appendix L. In accordance

with the WER guidance and where

application of the WER is deemed

appropriate, EPA strongly encourages

the application of the WER on a

watershed or water body basis in

California as opposed to application on

a discharger-by-discharger basis. This

approach is technically sound, an

efficient use of resources, and allowable

for NPDES permitting authorities.

The rule proposes that a default WER

value of 1.0 will be assumed, if no sitespecific WER will be determined. To

use a WER other than the default of 1.0,

the rule proposes that the WER must be

determined as set forth in EPA’s WER

guidance or determined by another

scientifically defensible method that has

been adopted by the State as part of its

water quality standards program and

approved by EPA.

The WER is a more comprehensive

mechanism for addressing

bioavailability issues than simply

expressing the criteria in terms of

dissolved metal. Consequently,

expressing the criteria in terms of

dissolved metal, as done in today’s

proposed rule for California, does not

completely eliminate the utility of the

WER. This is particularly true for

copper, a metal that forms reducedtoxicity complexes with dissolved

organic matter.

The Interim Guidance on

Determination and Use of Water-Effect

Ratios for Metals explains the

relationship between WERs for

dissolved criteria and WERs for total

recoverable criteria. Dissolved

measurements are to be used in the sitespecific toxicity testing underlying the

WERs for dissolved criteria. Because
42174 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

WERs for dissolved criteria generally are

little affected by elevated particulate

concentrations, EPA expects those

WERs to be somewhat less than WERs

for total recoverable criteria in such

situations. Nevertheless, after the sitespecific ratio of dissolved to total metal

has been taken into account, EPA

expects a permit limit derived using a

WER for a dissolved criterion to be

similar to the permit limit that would be

derived from the WER for the

corresponding total recoverable

criterion.

e. Saltwater Copper Criteria

The saltwater copper criteria for

aquatic life in today’s proposed rule are

4.8 μg/l (CMC) and 3.1 μg/l (CCC) in the

dissolved form. New data including data

collected from studies for the New

York/New Jersey Harbor and the San

Francisco Bay indicated a need to revise

the copper criteria document to reflect

a change in the saltwater CMC and CCC

aquatic life values. EPA conducted a

comprehensive literature search and

added toxicity test data for seven new

species to the database for the saltwater

copper criteria. EPA believes these new

data have national implications and the

national criteria guidance now contain a

CMC of 4.8 μg/l dissolved and a CCC of

3.1 μg/l dissolved. In the amendments to

the NTR, EPA noticed the availability of

data to support these changes to the

NTR, and solicited comments. The data

can be found in the draft document

entitled, Ambient Water Quality

Criteria—Copper, Addendum 1995. This

document is available from the Office of

Water Resource Center and is available

for review in the administrative record

for this proposed rule. EPA is now

requesting comments on these revised

criteria as applied to the State of

California. Commenters who wish to

refer to their comments on the Notice of

Availability must resubmit a copy of

their previous comments.

f. Chronic Averaging Period

In establishing water quality criteria,

EPA generally recommends an

‘‘averaging period’’ which reflects the

duration of exposure required to elicit

effects in individual organisms (TSD,

Appendix D–2.) The CCC is intended to

be the highest concentration that could

be maintained indefinitely in a water

body without causing an unacceptable

effect on the aquatic community or its

uses. (TSD, Appendix D–1). As aquatic

organisms do not generally experience

steady exposure, but rather fluctuating

exposures to pollutants, and because

aquatic organisms can generally tolerate

higher concentrations of pollutants over

a shorter periods of time, EPA expects

that the concentration of a pollutant can

exceed the CCC without causing an

unacceptable effect if (a) the magnitude

and duration of exceedences are

appropriately limited and (b) there are

compensating periods of time during

which the concentration is below the

CCC. This is done by specifying a

duration of an ‘‘averaging period’’ over

which the average concentration should

not exceed the CCC more often than

specified by the frequency (TSD,

Appendix D–1).

EPA is proposing a 4-day averaging

period for chronic criteria, which means

that measured or predicted ambient

pollutant concentrations should be

averaged over a 4-day period to

determine attainment of chronic criteria.

EPA acknowledges that the State may

develop and adopt an averaging period

that differs from EPA’s

recommendation, so long as it is

scientifically supportable.

The most important consideration for

setting an appropriate averaging period

is the length of time that sensitive

organisms can tolerate exposure to a

pollutant at levels exceeding a criterion

without showing adverse effects on

survival, growth, or reproduction. EPA

believes that the chronic averaging

period must be shorter than the duration

of the chronic tests on which the CCC

is based, since, in some cases, effects are

elicited before exposure of the entire

duration. Most of the toxicity tests used

to establish the chronic criteria are

conducted using steady exposure to

toxicants for a least 28 days. (TSD, page

35). Some chronic tests, however, are

much shorter than this (TSD, Appendix

D–2). EPA selected the 4-day averaging

period based on the shortest duration in

which chronic test effects are sometimes

observed for certain species and

toxicants. In addition, EPA believes that

the results of some chronic tests are due

to an acute effect on a sensitive life stage

that occurs some time during the test,

rather than being caused by long-term

stress or long-term accumulation of the

test material in the organisms.

Additional discussion of the rationale

for the 4-day averaging period is

contained in Appendix D of the TSD.

Balancing all of the above factors and

data, EPA believes that the 4-day

averaging period falls within the

scientifically reasonable range of values

for choice of the averaging period, and

is an appropriate length of time of

pollutant exposure to ensure protection

of sensitive organisms.

EPA established a 4-day averaging

period in the NTR. In settlement of

litigation on the NTR, EPA stated that it

was ‘‘in the midst of conducting,

sponsoring, or planning research related

to the basis for and application of’’

water quality criteria and mentioned the

issue of averaging period. See Partial

Settlement Agreement in American

Forest and Paper Ass’n, Inc. et al. v.

U.S. EPA (Consolidated Case No. 93–

0694 (RMU), D.D.C.). EPA is reevaluating issues raised about averaging

periods and will, if appropriate, revise

the 1985 Guidelines.

EPA received public comment

relevant to the averaging period during

the comment period for the 1995

Amendments to the NTR (40 CFR

22228, May 4, 1995), although these

public comments did not address the

chronic averaging period separately

from the allowable excursion frequency

and the design flow. These commenters

argued that a once-in-3-year excursion

frequency for 4-day average

concentrations, or a 7Q10 design flow,

was unnecessarily restrictive. For

chronic criteria, they noted that EPA has

approved the use of a 30Q3 design flow

in Colorado, a 30Q5 design flow in

Maryland, and a 1 percent exceedance

frequency in Pennsylvania. Comments

recommended that EPA use the 30Q5

design flow for chronic criteria.

While EPA is undertaking analysis of

the chronic design conditions as part of

the revisions to the 1985 Guidelines,

EPA has not yet completed this work.

Until this work is complete, for the

reasons set forth in the TSD, EPA

continues to believe that the 4-day

chronic averaging period represents a

reasonable, defensible value for this

parameter.

g. Hardness

Freshwater aquatic life criteria for

certain metals are expressed as a

function of hardness because hardness

and/or water quality characteristics that

are usually correlated with hardness can

reduce or increase the toxicities of some

metals. Hardness is used as a surrogate

for a number of water quality

characteristics which affect the toxicity

of metals in a variety of ways. Increasing

hardness has the effect of decreasing the

toxicity of metals. Water quality criteria

to protect aquatic life may be calculated

at different concentrations of hardnesses

measured in mg/l as CaCO3.

Section 131.38(b)(2) of the proposed

rule presents the hardness-dependent

equations for freshwater metals criteria.

For example, using the equation for

zinc, the total recoverable CMCs at a

hardness of 10, 50, 100 or 200 mg/l as

CaCO3 are 17, 67, 120 and 220 μg/l,

respectively. Thus, the specific value in

the table in the proposed regulatory text

is for illustrative purposes only. Most of

the data used to develop these hardness

equations for deriving aquatic life
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42175

criteria for metals were in the range of

25 mg/l to 400 mg/l as CaCO3, and the

formulas are therefore most accurate in

this range. The majority of surface

waters nationwide and in California

have a hardness of less than 400 mg/l

as CaCO3.

In the past, EPA generally

recommended that 25 mg/l as CaCO3 be

used as a default hardness value in

deriving freshwater aquatic life criteria

for metals when the ambient (or actual)

hardness value is below 25 mg/l as

CaCO3. However, use of the approach

results in criteria that may not be fully

protective. Therefore, for waters with a

hardness of less than 25 mg/l as CaCO3,

criteria should be calculated using the

actual ambient hardness of the surface

water.

In the past, EPA generally

recommended that if the hardness was

over 400 mg/l, two options were

available: (1) Calculate the criterion

using a default WER of 1.0 and using a

hardness of 400 mg/l in the hardness

equation; or (2) calculate the criterion

using a WER and the actual ambient

hardness of the surface water in the

equation. Use of the second option is

expected to result in the level of

protection intended in the 1985

Guidelines whereas use of the first

option is thought to result in a lower

aquatic life criterion. At high hardness

there is an indication that hardness and

related inorganic water quality

characteristics do not have as much of

an effect on toxicity of metals as they do

at lower hardnesses. Related water

quality characteristics do not correlate

as well at higher hardnesses as they do

at lower hardnesses. Therefore, if

hardness is over 400 mg/l as CaCO3, a

hardness of 400 mg/l as CaCO3 should

be used with a default WER of 1.0;

alternatively, the WER and actual

hardness of the surface water may be

used.

EPA requested comments in the NTR

amendments on the use of actual

ambient hardness for calculating criteria

when the hardness is below 25 mg/l as

CaCO3, and when hardness is greater

than 400 mg/l as CaCO3. Most of the

comments received were in favor of

using the actual hardness with the use

of the water-effect ratio (1.0 unless

otherwise specified by the permitting

authority) when the hardness is greater

than 400 mg/l as CaCO3. A few

commenters did not want the watereffect ratio to be mandatory in

calculating hardness, and other

commenters had concerns about being

responsible for deriving an appropriate

water-effect ratio. Overall, the

commenters were in favor of using the

actual hardness when calculating

hardness-dependent freshwater metals

criteria for hardness between 0–400 mg/

l as CaCO3. EPA took those comments

into account in proposing today’s

proposed rule.

A hardness equation is most accurate

when the relationships between

hardness and the other important

inorganic constituents, notably

alkalinity and pH, are nearly identical

in all of the dilution waters used in the

toxicity tests and in the surface waters

to which the equation is to be applied.

If an effluent raises hardness but not

alkalinity and/or pH, using the hardness

of the downstream water might provide

a lower level of protection than

intended by the 1985 guidelines. If it

appears that an effluent causes hardness

to be inconsistent with alkalinity and/or

pH, the intended level of protection will

usually be maintained or exceeded if

either (1) data are available to

demonstrate that alkalinity and/or pH

do not affect the toxicity of the metal,

or (2) the hardness used in the hardness

equation is the hardness of upstream

water that does not contain the effluent.

The level of protection intended by the

1985 guidelines can also be provided by

using the WER procedure.

In some cases, capping hardness at

400 mg/l might result in a level of

protection that is higher than that

intended by the 1985 guidelines, but

any such increase in the level of

protection can be overcome by use of

the WER procedure.

For metals whose criteria are

expressed as hardness equations, use of

the WER procedure will generally be

intended to account for effects of such

water quality characteristics as total

organic carbon on the toxicities of

metals. The WER procedure is equally

useful for accounting for any deviation

from a hardness equation in a site water.

3. Human Health Criteria

EPA’s CWA section 304(a) human

health criteria guidance provides

criteria recommendations to minimize

adverse human effects due to substances

in ambient water. EPA’s CWA section

304(a) criteria guidance for human

health are based on two types of

biological endpoints: (1) Carcinogenicity

and (2) systemic toxicity (i.e., all other

adverse effects other than cancer). Thus,

there are two procedures for assessing

these health effects: one for carcinogens

and one for non-carcinogens.

EPA’s human health guidelines

assume that carcinogenicity is a ‘‘nonthreshold phenomenon,’’ that is, there

are no ‘‘safe’’ or ‘‘no-effect levels’’

because even extremely small doses are

assumed to cause a finite increase in the

incidence of the effect (i.e., cancer).

Therefore, EPA’s water quality criteria

guidance for carcinogens are presented

as pollutant concentrations

corresponding to increases in the risk of

developing cancer. See Human Health

Guidelines at 45 FR 79347.

For pollutants that do not manifest

any apparent carcinogenic effect in

animal studies (i.e., systemic toxicants),

EPA assumes that the pollutant has a

threshold below which no effect will be

observed. This assumption is based on

the premise that a physiological

mechanism exists within living

organisms to avoid or overcome the

adverse effect of the pollutant below the

threshold concentration.

The human health risks of a substance

cannot be determined with any degree

of confidence unless dose-response

relationships are quantified. Therefore,

a dose-response assessment is required

before a criterion can be calculated. The

dose-response assessment determines

the quantitative relationships between

the amount of exposure to a substance

and the onset of toxic injury or disease.

Data for determining dose-response

relationships are typically derived from

animal studies, or less frequently, from

epidemiological studies in exposed

populations.

The dose-response information

needed for carcinogens is an estimate of

the carcinogenic potency of the

compound. Carcinogenic potency is

defined here as a general term for a

chemical’s human cancer-causing

potential. This term is often used

loosely to refer to the more specific

carcinogenic or cancer slope factor

which is defined as an estimate of

carcinogenic potency derived from

animal studies or epidemiological data

of human exposure. It is based on

extrapolation from test exposures of

high doses over relatively short periods

of time to more realistic low doses over

a lifetime exposure period by use of

linear extrapolation models. The cancer

slope factor, q1*, is EPA’s estimate of

carcinogenic potency and is intended to

be a conservative upper bound estimate

(e.g. 95% upper bound confidence

limit).

For non-carcinogens, EPA uses the

reference dose (RfD) as the dose

response parameter in calculating the

criteria. For non-carcinogens, oral RfD

assessments (hereinafter simply ‘‘RfDs’’)

are developed based on pollutant

concentrations that cause threshold

effects. The RfD is an estimate (with

uncertainty spanning perhaps an order

of magnitude) of a daily exposure to the

human population (including sensitive

subgroups) that is likely to be without

appreciable risk of deleterious effects

during a lifetime. See Human Health
42176 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

Guidelines. The RfD was formerly

referred to as an ‘‘Acceptable Daily

Intake’’ or ADI. The RfD is useful as a

reference point for gauging the potential

effect of other doses. Doses that are less

than the RfD are not likely to be

associated with any health risks, and are

therefore less likely to be of regulatory

concern. As the frequency of exposures

exceeding the RfD increases and as the

size of the excess increases, the

probability increases that adverse effect

may be observed in a human

population. Nonetheless, a clear

conclusion cannot be categorically

drawn that all doses below the RfD are

‘‘acceptable’’ and that all doses in

excess of the RfD are ‘‘unacceptable.’’ In

extrapolating non-carcinogen animal

test data to humans to derive an RfD,

EPA divides a no-observed-effect dose

observed in animal studies by an

‘‘uncertainty factor’’ which is based on

professional judgment of toxicologists

and typically ranges from 10 to 10,000.

For CWA section 304(a) human health

criteria development, EPA typically

considers only exposures to a pollutant

that occur through the ingestion of

water and contaminated fish and

shellfish. Thus, the criteria are based on

an assessment of risks related to the

surface water exposure route only where

designated uses are drinking water and

fish and shellfish consumption.

The assumed exposure pathways in

calculating the criteria are the

consumption of 2 liters per day of water

at the criteria concentration and the

consumption of 6.5 grams per day of

fish and shellfish contaminated at a

level equal to the criteria concentration

but multiplied by a ‘‘bioconcentration

factor.’’ The use of fish and shellfish

consumption as an exposure factor

requires the quantification of pollutant

residues in the edible portions of the

ingested species.

Bioconcentration factors (BCFs) are

used to relate pollutant residues in

aquatic organisms to the pollutant

concentration in ambient waters. BCFs

are quantified by various procedures

depending on the lipid solubility of the

pollutant. For lipid soluble pollutants,

the average BCF is calculated from the

weighted average percent lipids in the

edible portions of fish and shellfish,

which is about 3%; or it is calculated

from theoretical considerations using

the octanol/water partition coefficient.

For non-lipid soluble compounds, the

BCF is determined empirically. The

assumed water consumption is taken

from the National Academy of Sciences

publication Drinking Water and Health

(1977). (Referenced in the Human

Health Guidelines.) This value is

appropriate as it includes a margin of

safety so that the general population is

protected. See also EPA’s discussion of

the 2.0 liters/day assumption at 61 FR

65183 (Dec. 11, 1996). The 6.5 grams per

day contaminated fish and shellfish

consumption value was equivalent to

the average per-capita consumption rate

of all (contaminated and noncontaminated) freshwater and estuarine

fish and shellfish for the U.S.

population. See Human Health

Guidelines.

EPA assumes in calculating water

quality criteria that the exposed

individual is an average adult with body

weight of 70 kilograms. The issue of

concern is dose per kilogram of body

weight. EPA assumes 6.5 grams per day

of contaminated fish and shellfish

consumption and 2.0 liters per day of

contaminated drinking water

consumption for a 70 kilogram person

in calculating the criteria. Persons of

smaller body weight are expected to

ingest less contaminated fish and

shellfish and water, so the dose per

kilogram of body weight is generally

expected to be roughly comparable.

There may be subpopulations within

a state, such as subsistence anglers who

as a result of greater exposure to a

contaminant, are at greater risk than the

hypothetical 70 kilogram person eating

6.5 grams per day of maximally

contaminated fish and shellfish and

drinking 2.0 liters per day of maximally

contaminated drinking water. For

example, individuals that ingest ten

times more of a carcinogenic pollutant

than is assumed in derivation of the

criteria at a 10¥6 risk level will be

protected to a 10¥5 level, which EPA

has historically considered to be

adequately protective. There may,

nevertheless, be circumstances where

site-specific numeric criteria that are

more stringent than the statewide

criteria are necessary to adequately

protect highly exposed subpopulations.

Although EPA intends to focus on

promulgation of appropriate statewide

criteria that will reduce risks to all

exposed individuals, including highly

exposed subpopulations, site-specific

criteria may be developed subsequently

by the State where warranted to provide

necessary additional protection. See

Human Health Guidelines, Issue 8.

EPA has a process to develop a

scientific consensus on oral reference

dose assessments and carcinogenicity

assessments (hereinafter simply cancer

slope factors or slope factors or q1*s).

Through this process, EPA develops a

consensus of Agency opinion which is

then used throughout EPA in risk

management decision-making. EPA

maintains an electronic data base which

contains the official Agency consensus

for oral RfD assessments and

carcinogenicity assessments which is

known as the Integrated Risk

Information System (IRIS). It is available

for use by the public on the National

Institutes of Health’s National Library of

Medicine’s TOXNET system, and

through diskettes from the National

Technical Information Service (NTIS).

(NTIS access number is PB 90–591330.)

Section 304(a)(1) of the CWA requires

EPA to periodically revise its criteria

guidance to reflect the latest scientific

knowledge: ‘‘(A) on the kind and extent

of all identifiable effects on health and

welfare * * * ; (B) on the concentration

and dispersal of pollutants, or their

byproducts, through biological,

physical, and chemical processes; and

(C) on the effects of pollutants on the

biological community diversity,

productivity, and stability, including

information on the factors affecting

eutrophication rates of organic and

inorganic sedimentation for varying

types of receiving waters.’’ In

developing up-to-date water quality

criteria for the protection of human

health, EPA consistently relies upon the

most recent IRIS values (RfDs and q1*s)

as the toxicological basis in the criterion

calculation. IRIS reflects EPA’s most

current consensus on the toxicological

assessment for a chemical. In

developing the criteria in today’s

proposed rule, the most recent IRIS

values were used together with

currently accepted exposure parameters

for bioconcentration, fish and shellfish

and water consumption, and body

weight. The IRIS cover sheet for each

pollutant criteria included in today’s

proposed rule is contained in the

administrative record.

For the human health criteria

included in today’s proposed rule, EPA

used the Human Health Guidelines on

which criteria recommendations from

the appropriate CWA section 304(a)

criteria guidance document were based.

(These documents are also placed in the

administrative record for today’s

proposed rule.) Where EPA has changed

any parameters in IRIS used in criteria

derivation since issuance of the criteria

guidance document, EPA recalculated

the criteria recommendation with the

latest IRIS information. Thus, there are

differences between the original criteria

guidance document recommendations,

and those in this proposed rule, but this

proposed rule presents EPA’s most

current CWA section 304(a) criteria

recommendation. The basis (q1* or RfD/

ADI) and BCF for each pollutant

criterion in today’s proposed rule is

contained in the rule’s Administrative

Record Matrix which is included in the

administrative record for the proposed
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42177

rule. In addition, all recalculated human

health numbers are denoted by an ‘‘a’’

in the criteria matrix in 40 CFR

131.38(b)(1) of the proposed rule. The

pollutants for which a revised human

health criterion has been calculated

since the December 1992 NTR include:

mercury; dichlorobromomethane; 1,2-

dichloropropane; 1,2-transdichloroethylene; 2,4-dimethylphenol;

acenaphthene; benzo(a)anthracene;

benzo(a)pyrene; benzo(b)flouranthene;

benzo(k)flouranthene; 2-

chloronaphthalene; chrysene;

dibenzo(a,h)anthracene; indeno(1,2,3-

cd)pyrene; N-nitrosodi-n-propylamine;

alpha-endosulfan; beta-endosulfan;

endosulfan sulfate; 2-chlorophenol;

butylbenzyl phthalate; and

polychlorinated biphenyls.

In November of 1991, the proposed

NTR presented criteria for several

pollutants in parentheses. These were

pollutants for which, in 1980,

insufficient information existed to

develop human health water quality

criteria, but for which, in 1991,

sufficient information existed. Since

these criteria did not undergo the public

review and comment in a manner

similar to the other water quality criteria

presented in the NTR (for which

sufficient information was available in

1980 to develop a criterion, as presented

in the 1980 criteria guidance

documents), they were not proposed for

adoption into the water quality criteria,

but were presented to serve as notice for

inclusion in future state triennial

reviews. Today’s rule proposes criteria

for these nine pollutants: copper; 1, 2-

dichloropropane; 1,2-transdichloroethylene; 2,4-dimethylphenol;

acenaphthene; 2-chloronaphthalene; Nnitrosodi-n-propylamine; 2-

chlorophenol; butylbenzene phthalate.

All the criteria are based on IRIS

values—either an RfD or q1*—which

were listed on IRIS as of November

1991, the date of the proposed NTR.

These values have not changed since the

final NTR was published in December of

1992. The rule’s Administrative Record

Matrix in the administrative record of

today’s proposed rule contains the

specific RfDs, q1*s, and BCFs used in

calculating these criteria.

Potential Changes to the Human

Health Criteria Methodology: EPA

expects to propose in the near future

several changes to the 1980 ambient

water quality criteria derivation

guidelines (the Human Health

Guidelines). The methodology revisions

anticipated reflect significant scientific

advances that have occurred during the

past several years in such key areas as

cancer and noncancer risk assessments,

exposure assessments and

bioaccumulation. Some anticipated

areas of major change, which are being

considered in this process include:

1. The new Proposed Guidelines on

Carcinogen Risk Assessment emphasize

the consideration of mode of action and

route of exposure. A weight of evidence

narrative will be used instead of the

traditional alphanumeric classification

(e.g., A, B, C, D, E carcinogens). For dose

response assessments, two steps will be

involved: determining the range of

observation (observed effect) and the

range of extrapolation. To characterize

the cancer potency, a biologically-based

chemical-specific model will be used. In

many cases, however, sufficient data

may not exist to apply a biological based

model. In these cases, linear and

nonlinear defaults will be used. A linear

default will be used for those chemicals

which indicate they are DNA reactive or

when other evidence supports linearity.

In addition, if a chemical is not DNA

reactive but insufficient data exist to

characterize a nonlinear mode of action,

linearity will be assumed and a linear

default will be recommended. The

nonlinear default (margin of exposure

approach) will be used for those

chemicals which are not DNA reactive

and for those for which sufficient data

to characterize a nonlinear mode of

action exist.

2. For noncarcinogens, the concept of

an expressing an RfD as a range rather

than a single value will be presented for

comment. In developing water quality

criteria, EPA will provide a default RfD

which, in most cases, will be the

midpoint of the range, commonly

referred to as the point estimate.

Alternative approaches, such as the

benchmark dose and categorical

regression analysis may be employed in

developing an RfD and analyzing the

risk above the RfD point estimate.

3. Default fish and shellfish

consumption values are presented for

the general population, for sportfishers,

and for subsistence fishers, replacing

the single value of 6.5 grams/day used

in the 1980 guidance. States may use a

fish and shellfish intake level derived

from local data on fish and shellfish

consumption in place of the default

values provided. However, the fish and

shellfish intake level chosen must be

protective of highly exposed individuals

in the population.

4. All criteria should be derived using

a bioaccumulation factor (BAF); none

should be derived using a

bioconcentration factor (BCF), which

was used in the 1980 guidance.

5. As an alternative to expressing

ambient water quality criteria as a water

concentration, criteria may also be

expressed in terms of fish tissue

concentration. For some substances,

particularly those that are expected to

exhibit substantial bioaccumulation, the

ambient water quality criteria derived

may have extremely low values,

possibly below the practical limits for

detecting and quantifying the substance

in the water column. It may be more

practical and meaningful in these cases

to focus on the concentration of those

substances in fish tissue, since fish

ingestion would be the predominant

source of exposure for these substances

that bioaccumulate.

6. When deriving ambient water

quality criteria for noncarcinogens and

nonlinear carcinogens, a factor (referred

to as the relative source contribution)

should be included to account for other

non-water exposure sources so that the

entire RfD will not be not allocated to

drinking water and fish consumption

alone.

For more details on these changes and

others, please refer to the upcoming

Federal Register notice.

It should be noted that the changes

outlined above may result in significant

numeric changes in the ambient water

quality criteria. For example, for those

chemicals which are bioaccumulative in

nature (e.g., with bioconcentration

factors (BCFs) of 300 or more),

bioaccumulation factors may be

developed which are 1–3 orders of

magnitude greater than the BCFs

developed in 1980. This would result in

a criterion which is 1–3 orders of

magnitude more stringent, if all other

parameters (such as RfDs and q1 *s)

remain roughly unchanged.

EPA will continue to rely on existing

criteria as the basis for regulatory and

non-regulatory decisions, until EPA

revises and reissues a 304(a) criteria

guidance using the revised final human

health criterion methodology. The

existing criteria are still viewed as

scientifically acceptable by EPA. The

intention of the methodology revisions

is to present the latest scientific

advancements in the areas of risk and

exposure assessment in order to

incrementally improve the already

sound toxicological and exposure bases

for these criteria. As EPA’s current

human health criteria are the product of

several years worth of development, it is

reasonable to assume that revisiting all

existing criteria could require

comparable amounts of time and

resources. Given these circumstances,

EPA is proposing a process for revisiting

these criteria as part of the overall

revisions to the methodology for

deriving human health criteria that is

expected to be published in the Federal

Register in 1997.
42178 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

The State of California in its Ocean

Plan, adopted in 1990 and approved by

EPA in 1991, established numerical

water quality criteria using an average

fish and shellfish consumption rate of

23 grams per day. This value is based

on an earlier California Department of

Health Services estimate. The State is

currently in the process of readopting its

water quality control plans for inland

surface waters, enclosed bays, and

estuaries. The State intends to consider

information on fish and shellfish

consumption rates evaluated and

summarized in a recent report prepared

by the State’s Office of Environmental

Health Hazard Assessment. The report,

which is undergoing final evaluation, is

expected to be made public in 1997.

EPA supports the State’s use of any

appropriate higher state-specific fish

and shellfish consumption rates in its

readoption of criteria in its statewide

plans.

a. 2,3,7,8–TCDD (Dioxin) Criteria

In today’s action, EPA is proposing

human health water quality criteria for

2,3,7,8-tetrachlorodibenzo-p-dioxin

(‘‘dioxin’’) at the same levels as

promulgated in the NTR, as amended.

These criteria are derived from EPA’s

1984 CWA section 304(a) criteria

guidance document for dioxin.

EPA has been evaluating the health

threat posed by dioxin nearly

continuously for well over a decade.

Following issuance of the 1984 criteria

guidance document, evaluating the

health effects of dioxin and

recommending human health criteria for

dioxin, EPA prepared draft

reassessments reviewing new scientific

information relating to dioxin in 1985

and 1988. EPA’s Science Advisory

Board (SAB), reviewing the 1988 draft

reassessment, concluded that while the

risk assessment approach used in 1984

criteria guidance document had

inadequacies, a better alternative was

unavailable (see SAB’s Dioxin Panel

Review of Documents from the Office or

Research and Development relating to

the Risk and Exposure Assessment of

2,3,7,8–TCDD (EPA—SAB–EC–90–003,

November 28, 1989) included in the

administrative record for today’s

proposed rule). Between 1988 and 1990,

EPA issued numerous reports and

guidances relating to the control of

dioxin discharges from pulp and paper

mills. See e.g., EPA Memorandum,

‘‘Strategy for the Regulation of

Discharges of PHDDs & PHDFs from

Pulp and Paper Mills to the Waters of

the United States,’’ from Asst.

Administrator for Water to Regional

Water Mgmt Div. Directors and NPDES

State Directors, dated May 21, 1990 (AR

NL–16); EPA Memorandum, ‘‘State

Policies, Water Quality Standards, and

Permit Limitations Related to 2,3,7,8–

TCDD in Surface Water,’’ from Assistant

Administrators to Water Management

Div. Directors, dated January 5, 1990

(AR VA–66). These documents are

available in the administrative record

for today’s proposed rule.

In 1991, EPA’s Administrator

announced another scientific

reassessment of the risks of exposure to

dioxin (see Memorandum from

Administrator William K. Reilly to Erich

W. Bretthauer, Assistant Administrator

for Research and Development and E.

Donald Elliott, General Counsel, entitled

Dioxin: Follow-Up to Briefing on

Scientific Developments, April 8, 1991,

included in the administrative record

for today’s proposed rule). At that time,

the Administrator made clear that while

the reassessment was underway, EPA

would continue to regulate dioxin in

accordance with existing Agency policy

and existing risk methodologies.

Thereafter, the Agency proceeded to

regulate dioxin in a number of

environmental programs, including

standards under the Safe Drinking

Water Act and the Clean Water Act.

The Administrator’s promulgation of

the dioxin human health criteria in the

1992 NTR affirmed his decision that the

ongoing reassessment should not defer

or delay regulating this potent

contaminant, and further, that the risk

assessment in the 1984 criteria guidance

document for dioxin continued to be

scientifically defensible. Until the

reassessment process was completed,

the Agency could not ‘‘say with any

certainty what the degree or directions

of any changes in the risk estimates

might be’’ (57 F. R. at 60863–64).

The basis for the dioxin criteria as

well as the decision to include the

dioxin criteria in the 1992 NTR pending

the results of the reassessment were

challenged. See American Forest and

Paper Ass’n, Inc. et al. v. U.S. EPA

(Consolidated Case No. 93–0694 (RMU)

D.D.C.). By order dated September 4,

1996, the Court upheld EPA’s decision.

EPA’s brief and the Court’s decision are

included in the administrative record

for today’s proposed rule.

EPA has undertaken significant effort

toward completion of the dioxin

reassessment. On September 13, 1994,

EPA released for public review and

comment a draft reassessment of

toxicity and exposure to dioxin. See

Health Assessment Document for

2,3,7,8-Tetrachlorobenzo-p-Dioxin

(TCDD) and Related Compounds, U.S.

EPA, 1994. EPA is currently addressing

comments made by the public and the

SAB and anticipates that the final

revised reassessment will go to the SAB

in the near future. With today’s

proposal, the Administrator reaffirms

that, notwithstanding the on-going risk

reassessment, EPA intends to continue

to regulate dioxin to avoid further harm

to public health, and the basis for the

dioxin criteria, both in terms of the

cancer potency and the exposure

estimates, remains scientifically

defensible. The fact that EPA is

reassessing the risk of dioxin, virtually

a continuous process to evaluate new

scientific information, does not mean

that the current risk assessment is

‘‘wrong’’. It continues to be EPA’s

position that until the risk assessment

for dioxin is revised, EPA supports and

will continue to use the existing risk

assessment for the regulation of dioxin

in the environment. Accordingly, EPA

today proposes dioxin criteria based on

the 1984 criteria guidance document for

dioxin and promulgated in the NTR in

1992.

Toxicity Equivalency: The State of

California, in its 1991 water quality

control plans, adopted human health

criteria for dioxin and dioxin-like

compounds based on the concept of

toxicity equivalency (TEQ) using

toxicity equivalency factors (TEFs). EPA

Region 9 reviewed and approved the

State’s use of the TEQ concept and TEFs

in setting the State’s human health

water quality criteria for dioxin and

dioxin-like compounds.

In 1987, EPA formally embraced the

TEQ concept as an interim procedure to

estimate the risks associated with

exposures to 210 chlorinated dibenzo-pdioxin and chlorinated dibenzofuran

(CDD/CDF) congeners, including

2,3,7,8–TCDD. This procedure uses a set

of derived TEFs to convert the

concentration of any CDD/CDF congener

into an equivalent concentration of

2,3,7,8–TCDD. In 1989, EPA updated its

TEFs based on an examination of

relevant scientific evidence and a

recognition of the value of international

consistency. This updated information

can be found in EPA’s 1989 Update to

the Interim Procedures for Estimating

Risks Associated with Exposures to

Mixtures of Chlorinated Dibenzo-pdioxins and -dibenzofurans (CDDs and

CDFs) (EPA /625/3–89/016, March

1989). EPA had been active in an

international effort aimed at adopting a

common set of TEFs (International

TEFs/89 or I–TEFs/89), to facilitate

information exchange on environmental

contamination of CDD/CDF. This

document reflects EPA’s support of an

internationally consistent set of TEFs,

the I–TEFs/89.

EPA uses I–TEFs/89 in many of its

regulatory programs, and encourages
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42179

their use in state programs. EPA

supports and encourages the State of

California’s use of EPA’s 1989 Interim

Procedures in implementing the 2,3,7,8–

TCDD water quality criteria contained

in today’s proposed rule. The concept of

TEQ and the use of the I–TEFs/89, as

outlined in EPA’s 1989 Interim

Procedures, provide valuable guidance

in using the 2,3,7,8–TCDD water quality

criteria in setting National Pollutant

Discharge Elimination System (NPDES)

water quality-based permit limits that

are protective of human health for

dioxin and dioxin-like compounds.

b. Arsenic Criteria

EPA is not proposing human health

criteria for arsenic in today’s proposed

rule. EPA recognizes that EPA

promulgated human health water

quality criteria for arsenic for a number

of states in 1992 based on EPA’s 1980

section 304(a) criteria guidance for

arsenic as updated in IRIS. However, a

number of issues and uncertainties have

arisen concerning the health effects of

arsenic. These issues and uncertainties

(summarized in ‘‘Issues Related to

Health Risk of Arsenic’’ contained in the

administrative record for today’s

proposed rule) include arsenic exposure

evaluations, metabolism and

detoxification processes, analytical

methods, and effects at low doses. EPA

has determined that these issues and

uncertainties are sufficiently significant

to necessitate a careful evaluation of the

risks of arsenic exposure before the

Agency promulgates water quality

criteria for arsenic in additional states.

Today’s decision is consistent with the

recent decision by the Assistant

Administrator for Water (Memorandum

from R. Perciasepe to Assistant and

Regional Administrators dated February

6, 1995, also included in the

administrative record) deferring the

revision of the drinking water standard

of 0.05 mg/l for arsenic pending, among

other things, the review of the risk

assessment for arsenic. This review is

currently underway.

Given these circumstances, EPA has

made a risk management decision not to

propose human health criteria for

arsenic. Permitting authorities in

California should rely on existing

narrative water quality criteria to

establish effluent limitations as

necessary for arsenic. California has

previously expressed its science and

policy position by establishing a

criterion level of 5 μg/l for arsenic; EPA

recommends that permitting authorities

refer to that value in evaluating and

interpreting the narrative water quality

criteria.

c. Mercury Criteria

The criteria proposed here use the

latest RfD in EPA’s Integrated Risk

Information System (IRIS) and the

weighted average practical

bioconcentration factor (PBCF) from the

1980 section 304(a) criteria guidance

document for mercury. EPA considered

the approach used in the Great Lakes

Water Quality Initiative (GLI)

incorporating Bioaccumulation Factors

(BAFs), but rejected this approach for

reasons stated below. The equation used

here to derive an ambient water quality

criterion for mercury from exposure to

organisms and water is the following:

For organism and water consumption:

HHC

RfD BW

WC FC PBCF

= ×

+ × ( )

Where:

RfD = Reference Dose

BW = Body Weight

WC = Water Consumption

FC = Total Fish and Shellfish

Consumption per Day

PBCF = Practical Bioconcentration

Factor (weighted average)

For mercury, the most current RfD

from IRIS is 1×10¥4 mg/kg/day. The RfD

is derived from a benchmark dose

analysis using a parts per million (ppm)

maternal hair concentration as the

exposure surrogate and the combination

of all neurological effects in infants as

the response variable from the Marsh et.

al (1987) study. A Weibel model for

extra risk was used. The resulting

estimated dose at 10% extra risk was 11

ppm of maternal hair, or about 1×10¥3

mg/kg/day. An uncertainty factor of 10

was included to arrive at an RfD of

1×10¥4 mg/kg/day. This factor is

composed of a half-log of 10 for withinhuman variability and a half log of 10

for database insufficiency, notably the

lack of a two generation reproductive

study.

The body weight used in the equation

for the mercury criteria, as discussed in

the Human Health Guidelines, is a mean

adult human body weight of 70 kg. The

drinking water consumption rate, as

discussed in the Human Health

Guidelines, is 2.0 liters per day.

The fish and shellfish consumption

for mercury takes into account both

average fish and shellfish consumption

and average intake from each body of

water. The value for the fish and

shellfish consumption is based on the

average total intake of fish and shellfish

from fresh water, estuarine coastal and

open oceans (18.7 g/day). The average

individual fish and shellfish

consumption from freshwater bodies is

1.72 g/day (0.00172 kg), from estuarinecoastal waters is 4.78 g/day (0.00478

kg), and from open oceans is 12.2 g/day

(0.0122 kg). Species of fish and shellfish

used in the calculation are those from

which information was available on

human consumption on average

mercury concentration in edible tissue.

See Ambient Water Quality Criteria for

Mercury (EPA 440/5–80–058).

The BCF is defined as the ratio of

chemical concentration in the organism

to that in surrounding water.

Bioconcentration occurs through uptake

and retention of a substance from water

only, through gill membranes or other

external body surfaces. In the context of

setting exposure criteria it is generally

understood that the terms ‘‘BCF’’ and

‘‘steady-state BCF’’ are synonymous. A

steady-state condition occurs when the

organism is exposed for a sufficient

length of time that the ratio does not

change substantially.

The BCFs that were used herein are

the ‘‘Practical Bioconcentration Factors

(PBCFs)’’ that were derived in 1980:

5500 for fresh water, 3765 for estuarine

coastal waters, and 9000 for open

oceans. See pages C–100–1 of Ambient

Water Quality Criteria for Mercury (EPA

440/5–80–058) for a complete

discussion on the PBCF. Because of the

way they were derived, these PBCFs

take into account uptake from food as

well as uptake from water. A weighted

average PBCF was calculated to take

into account the average consumption

from the three waters using the

following equation:
42180 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

Weighted Average Practical BCF =

Σ

Σ

FC PBCF

FC

( ) ×

( )

= ( )( ) + ( )( ) + ( )( )

+ +

= =

0 00172 5500 0 00478 3765 0 0122 9000

0 00172 0 00478 0 0122

137 3

0 0187

7342 6

. . .

. . .

.

. .

Given the large value for the weighted

average PBCF, the contribution of

drinking water to total daily intake is

negligible so that assumptions

concerning the chemical form of

mercury in drinking water become less

important. The human health mercury

criteria proposed for this rule are based

on the latest RfD as listed in IRIS and

a weighted PBCF from the 1980 304(a)

criteria guidance document for mercury.

On March 23, 1995 (60 FR 15366),

EPA promulgated the Great Lakes Water

Quality Initiative (GLI). The GLI

incorporated bioaccumulation factors

(BAFs) in the derivation of criteria to

protect human health because it is

believed BAFs are a better predictor

than BCFs of the concentration of a

chemical within fish tissue as it

includes consideration of the uptake of

contaminants from all routes of

exposure. A bioaccumulation factor is

defined as the ratio (in L/kg) of a

substance’s concentration in tissue to

the concentration in the ambient water,

in situations where both the organism

and its food are exposed and the ratio

does not change substantially over time.

The final GLI establishes a hierarchy of

four methods for deriving BAFs for nonpolar organic chemicals: (1) Fieldmeasured BAFs; (2) predicted BAF

derived using a field-measured biotasediment accumulation factor; (3)

predicted BAFs derived by multiplying

a laboratory-measured BCF by a food

chain multiplier; and 4) predicted BAFs

derived by multiplying a BCF calculated

from the log Kow by a food-chain

multiplier. The final GLI developed

BAFs for trophic levels three and four

fish of the Great Lakes Basin.

Respectively, the BAFs for mercury for

trophic level 3 and 4 fish were: 27,900

and 140,000.

The BAF promulgated in the GLI was

developed specifically for the Great

Lakes System. It is uncertain whether

the BAFs of 27,900 and 140,000 are

appropriate for use in California at this

time, and thus, this proposal does not

use the BAF in setting the human health

criteria for mercury. To a considerable

degree the magnitude of the BAF for

mercury in a given system depends on

how much of the total mercury in that

system is present in the methylated

form. Methylation rates very widely

from one aquatic system to another for

reasons that are not fully understood.

Lacking the data, it is difficult to

determine if the BAF used in the GLI

represent the potential for mercury

bioaccumulation in surface waters in

California. It should be noted, however,

that there is no scientific reason to

believe that a true average BAF in

California, were it known, would be

lower than that developed for the Great

Lakes basin; that is, the true average for

California could be higher or lower than

the BAF developed for the GLI.

EPA is developing a national BAF for

mercury. The mercury BAF is part of the

Mercury Study Report to Congress: SAB

Review Draft (The Draft Report to

Congress) . The Draft Report to Congress

is currently available through NTIS

(EPA–452/R–96–001a–h) . The next step

is for the SAB to review the Draft Report

to Congress. After the SAB reviews the

Draft Report and the Agency makes

changes based on their comments, the

Report to Congress will be released with

a final national BAF for mercury. Once

the Report to Congress has been

publicly reviewed, and finalized, the

Agency will consider the science and

could make changes to the section

304(a) criteria guidance for mercury to

reflect the recommendation of the

Report to Congress. If the section 304(a)

criteria guidance for mercury changes,

states will be expected to review their

water quality standards for mercury and

determine if their standards are

protective.

d. Polychlorinated Biphenyls (PCBs)

Criteria

The NTR, as amended, calculated

human health criteria for PCBs using a

cancer potency factor of 7.7 per (mg/kg)/

day from the Agency’s IRIS. This cancer

potency factor was derived from the

Norback and Weltman (1985) study

which looked at rats that were fed

Aroclor 1260. The study used the

linearized multistage model with a

default cross-species scaling factor

(body weight ratio to the 2/3 power).

Although it is known that PCB

congeners vary greatly as to their

potency in producing biological effects,

for purposes of its carcinogenicity

assessment, EPA considered Aroclor

1260 to be representative of all PCB

mixtures. The Agency did not pool data

from all available congener studies or

generate a geometric mean from these

studies, since the Norback and Weltman

study was judged by EPA as acceptable,

and not of marginal quality, in design or

conduct as compared with other studies.

Thereafter, the Institute for Evaluating

Health Risks (IEHR, 1991) reviewed the

pathological slides from the Norback

and Weltman study, and concluded that

some of the malignant liver tumors

should have been interpreted as

nonmalignant lesions, and that the

cancer potency factor should be 5.1 per

(mg/kg)/day as compared with EPA’s 7.7

per (mg/kg)/day.

The Agency’s recent peer-reviewed

reassessment of the cancer potency of

PCBs published in a final report, PCBs:

Cancer Dose-Response Assessment and

Applications to Environmental Mixtures

(EPA/600/P–96/001F), adopts a different

approach that distinguishes among PCB

mixtures by using information on

environmental processes. (The report is

included in the administrative record of

today’s proposed rule.) The report

considers all cancer studies (which used

commercial mixtures only) to develop a

range of cancer potency factors, then

uses information on environmental

processes to provide guidance on

choosing an appropriate potency factor

for representative classes of

environmental mixtures and different

pathways. The reassessment provides

that, depending on the specific

application, either central estimates or

upper bounds can be appropriate.

Central estimates describe a typical

individual’s risk, while upper bounds

provide assurance (i.e., 95% confidence)

that this risk is not likely to be

underestimated if the underlying model

is correct. Central estimates are used for

comparing or ranking environmental

hazards, while upper bounds provide

information about the precision of the

comparison or ranking. In the

reassessment, the use of the upper

bound values were found to increase

cancer potency estimates by two or
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42181

three-fold over those using central

tendency. Upper bounds are useful for

estimating risks or setting exposurerelated standards to protect public

health, and are used by EPA in

quantitative cancer risk assessment.

Thus, the cancer potency of PCB

mixtures is determined using a tiered

approach based on environmental

exposure routes with upper-bound

potency factors (using a body weight

ratio to the 3/4 power) ranging from 0.07

(lowest risk and persistence) to 2 (high

risk and persistence) per (mg/kg)/day for

average lifetime exposures to PCBs. It is

noteworthy that bioaccumulated PCBs

appear to be more toxic than

commercial PCBs and appear to be more

persistent in the body. For exposure

through the food chain, risks can be

higher than other exposures.

EPA issued the final reassessment

report on September 27, 1996 and

updated IRIS to include the

reassessment on October 1, 1996. For

this proposed rule, EPA derived the

human health criteria for PCBs using a

cancer potency factor of 2 per (mg/kg)/

day, an upper bound potency factor

reflecting high risk and persistence.

This decision is based on recent

multimedia studies indicating that the

major pathway of exposure to persistent

toxic substances such as PCBs is via

dietary exposure (i.e., contaminated fish

and shellfish consumption).

Following is the calculation of the

human health criterion (HHC) for

organism and water consumption:

HHC RF BW g mg

q WC FC BCF

= × × ( )

× + × [ ] ( )

1 000

1

, /

*

μ

Where:

RF=Risk Factor=1 × 10 (¥6)

BW=Body Weight=70 kg

q1*=Cancer slope factor=2 kg-day/mg

WC=Water Consumption=2 l/day

FC=Fish and Shellfish

Consumption=0.0065 kg/day

BCF=Bioconcentration Factor=31,200

the HHC (μg/l)=0.00017 μg/l (rounded to

two significant digits).

Following is the calculation of the

human health criterion for organism

only consumption:

HHC RF BW g mg

q FC BCF = × × ( )

× ×

1 000

1

, /

*

μ

Where:

RF=Risk Factor=1 × 10 (¥6)

BW=Body Weight=70 kg

q1*=Cancer slope factor=2 kg-day/mg

FC=Total Fish and Shellfish

Consumption per Day=0.0065 kg/

day

BCF=Bioconcentration Factor=31,200

the HHC (μg/l)=0.00017 μg/l (rounded to

two significant digits).

The criteria are both equal to 0.00017

μg/l and apply to the total PCBs or

congener or isomer analyses (PCBs

exposures should not be characterized

in terms of aroclors). See PCBs: Cancer

Dose Response Assessment and

Application to Environmental Mixtures

(EPA/600/9–96–001F). For a discussion

of the body weight, water consumption,

and fish and shellfish consumption

factors, see the Human Health

Guidelines. For a discussion of the BCF,

see the 304(a) criteria guidance

document for PCBs (included in the

administrative record for this proposed

rulemaking).

e. Section 304(a) Human Health Criteria

Excluded

As is the case in the NTR, as

amended, today’s proposed rule does

not propose criteria for certain priority

pollutants for which CWA section

304(a) criteria guidance exists because

those criteria were not based on toxicity

to humans or aquatic organisms. The

basis for these particular criteria is

organoleptic effects (e.g., taste and odor)

which would make water and edible

aquatic life unpalatable but not toxic.

Because the basis for this rule is to

protect the public health and aquatic

life from toxicity consistent with the

language and intent in CWA section

303(c)(2)(B), EPA is promulgating

criteria only for those priority toxic

pollutants whose criteria

recommendations are based on toxicity.

The CWA section 304(a) human health

criteria based on organoleptic effects for

zinc and 3-methyl-4-chlorophenol are

excluded for this reason. See the 1992

NTR discussion at 57 FR 60864.

f. Cancer Risk Level

EPA’s CWA section 304(a) criteria

guidance documents for priority toxic

pollutants that are based on

carcinogenicity present concentrations

for upper bound risk levels of 1 excess

cancer case per 100,000 people (10¥5),

per 1,000,000 people (10¥6), and per

10,000,000 people (10¥7). However, the

criteria documents do not recommend a

particular risk level as EPA policy.

In today’s proposed rule, EPA is

proposing criteria that protect at an

incremental cancer risk level of one in

a million (10¥6) for all priority toxic

pollutants regulated as carcinogens,

consistent with those criteria

promulgated in the NTR, as amended,

for the State of California. The State had

requested EPA to use a 10¥6 risk level

for carcinogenic pollutants in the NTR.

In addition, standards adopted by the

State contained in the Enclosed Bays

and Estuaries Plan (EBEP), and the

Inland Surface Waters Plan (ISWP),

partially approved by EPA on November

6, 1991, and the Ocean Plan approved

by EPA on June 28, 1990, contain a risk

level of 10¥6 for most carcinogens.

Thus, the State has historically

protected at a 10¥6 risk level for

carcinogenic pollutants. For today’s

proposed rule, the State has indicated a

preference for EPA to propose criteria

for carcinogenic pollutants at a 10¥6

risk level, but to also discuss and

request comment on a 10¥5 risk level.

Therefore, EPA is explicitly requesting

comment on the adoption of a 10¥5 risk

level for carcinogenic pollutants

proposed in this rule for the State of

California. The effect of a 10¥5 risk level

will be to increase carcinogenic

pollutant criteria values (noted in

today’s proposed matrix by footnote c)

which are not already promulgated in

the NTR, as amended, by one order of

magnitude. For example, the proposed

organism-only criterion for gamma BHC

(pollutant number 105 in the matrix) is

0.013 μg/l; the criterion based on a 10¥5

risk level would be 0.13 μg/l.

The State, in its readoption of its

statewide plans for inland surface

waters and enclosed bays and estuaries

may consider other risk levels for

carcinogenic pollutants. EPA
42182 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

recommends that states consider

minimum risk levels in the range of

10¥4 to 10¥6 for carcinogenic priority

toxic pollutants to protect public health

and welfare. See Human Health

Guidelines.

F. Description of the Proposed Rule

1. Scope

Subpart (a), entitled ‘‘Scope’’, states

that this rule is a proposed

promulgation of criteria for priority

toxic pollutants in the State of

California for inland surface waters,

enclosed bays, and estuaries. Subpart (a)

also states that this rule contains an

authorizing compliance schedule

provision.

2. EPA Criteria for Priority Toxic

Pollutants

EPA’s proposed criteria for California

are presented in tabular form that will

appear at 40 CFR 131.38. For ease of

presentation, the table that appears in

this proposed rule combines water

quality criteria promulgated in the NTR,

as amended, that are outside the scope

of this rulemaking, with the proposed

criteria that are within the scope of

today’s proposed rule. This is intended

to help readers determine applicable

water quality criteria for the State of

California. The table contains several

footnotes for clarification; however,

when EPA promulgates the final rule,

the source of the criteria, either the

NTR, as amended, or this rulemaking,

may no longer be included as footnotes

to the table.

As proposed, subpart (b) presents a

matrix of the applicable EPA aquatic life

and/or human health criteria for priority

toxic pollutants. Section 303(c)(2)(B) of

the CWA addresses only pollutants

listed as ‘‘toxic’’ pursuant to section

307(a) of the CWA for which EPA has

developed section 304(a) criteria

guidance. As discussed earlier in this

preamble, the section 307(a) list of

toxics contains 65 compounds and

families of compounds, which

potentially include thousands of

specific compounds. Of these, the

Agency identified a list of 126 ‘‘priority

toxic pollutants’’ to implement the CWA

(see 40 CFR 131.36(b)). Reference in this

proposed rule to priority toxic

pollutants, toxic pollutants, or toxics

refers to the 126 priority toxic

pollutants.

EPA has not developed both aquatic

life and human health CWA section

304(a) criterion guidance for all of the

priority toxic pollutants. The matrix in

paragraph (b) contains human health

criteria in Column D for 100 priority

toxic pollutants which are divided into

criteria (Column 1) for water

consumption (i.e., 2.0 liters per day) and

aquatic organism consumption (i.e., 6.5

grams per day of aquatic organisms),

and into criteria (Column 2) for aquatic

organism only consumption. The term

aquatic organism includes fish and

shellfish such as shrimp, clams, oysters

and mussels. One reason the total

number of priority toxic pollutants with

criteria proposed today differs from the

total number of priority toxic pollutants

contained in earlier published CWA

section 304(a) criteria guidance is

because EPA has developed and is

proposing chromium criteria for two

valence states with respect to aquatic

life criteria. Thus, although chromium is

a single priority toxic pollutant, there

are two criteria for chromium for

aquatic life protection. See pollutant 5

in today’s proposed 40 CFR 131.38(b).

Another reason is that EPA is proposing

human health criteria for nine priority

pollutants for which health-based

national criteria have been calculated

based on information obtained from

EPA’s IRIS database (EPA provided

notice of these nine criteria in the NTR

for inclusion in future State triennial

reviews. See 57 FR 60848, 60890).

The matrix contains aquatic life

criteria for 30 priority pollutants. These

are divided into freshwater criteria

(Column B) and saltwater criteria

(Column C). These columns are further

divided into acute and chronic criteria.

The aquatic life criteria are considered

by EPA to be protective when applied

under the conditions described in the

section 304(a) criteria documents and in

the TSD. For example, water body uses

should be protected if the criteria are

not exceeded, on average, once every

three year period. It should be noted

that the criteria maximum

concentrations (the acute criteria) are

short-term concentrations and that the

criteria continuous concentrations (the

chronic criteria) are four-day averages. It

should also be noted that for certain

metals, the actual criteria are equations

which are included as footnotes to the

matrix. The toxicity of these metals is

water hardness dependent and may be

adjusted. The values shown in the table

are illustrative only, based on a

hardness expressed as calcium

carbonate of 100 mg/l. Finally, the

criterion for pentachlorophenol is pH

dependent. The equation is the actual

criterion and is included as a footnote.

The value shown in the matrix is for a

pH of 7.8.

Several of the freshwater aquatic life

criteria are incorporated into the matrix

in the format used in the 1980 criteria

methodology which uses a final acute

value instead of a continuous maximum

concentration. This distinction is noted

in footnote g of the table.

Proposed 40 CFR 131.38(c) would

establish the applicability of the criteria

to the State of California. Proposed 40

CFR 131.38(d) is described in Section F

of this preamble.

EPA’s purpose today is to propose the

numeric toxics criteria necessary for

California to meet the requirements of

the CWA. In order for such criteria to

achieve their intended purpose, the

implementation scheme must be such

that the final results protect aquatic life

and public health. In Section E of this

preamble, a discussion focuses on the

factors in EPA’s assessment of criteria

for carcinogens. For example, fish and

shellfish consumption rates,

bioaccumulation factors, and cancer

potency slopes are discussed. When any

one of these factors is changed, the

others must also be evaluated so that, on

balance, resulting criteria are adequately

protective.

Once an appropriate numeric

criterion is selected for either aquatic

life or human health protection, this

facilitates the calculation of water

quality-based effluent limits and/or total

maximum daily loads (TMDLs) for that

chemical. EPA has included in this rule

appropriate implementation factors

necessary to maintain the level of

protection intended. These factors are

included in subsection (c) of the

proposed rule.

For example, in order to do steady

state waste load allocation analyses,

most states have low flow values for

streams and rivers which establish flow

rates for various purposes. These low

flow values become design flows for

sizing treatment plants and developing

water quality-based effluent limits and/

or TMDLs. Historically, these design

flows were selected for the purposes of

waste load allocation analyses which

focused on instream dissolved oxygen

concentrations and protection of aquatic

life. With the publication of the 1985

TSD, EPA introduced hydrologically

and biologically based analyses for the

protection of aquatic life and human

health. (These concepts have been

expanded subsequently in EPA’s

Technical Guidance Manual for

Performing Wasteload Allocations, Book

6, Design Conditions, U.S. EPA, 1986 .

These new developments are included

in Appendix D of the revised TSD. The

discussion here is greatly simplified and

is provided to support EPA’s decision to

promulgate design flows for instream

flows and thereby maintain the

intended stringency of the criteria for

priority toxic pollutants.) EPA

recommended either of two methods for

calculating acceptable low flows, the
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42183

traditional hydrologic method

developed by the U.S. Geological

Survey and a biological based method

developed by EPA. Other methods for

evaluating the instream flow record may

be available; use of these methods may

result in TMDLs and/or water qualitybased effluent limitations which

adequately protect human health and/or

aquatic life. The results of either of

these two methods, or an equally

protective alternative method, may be

used.

The State of California may adopt

specific design flows for streams and

rivers to protect designated uses against

the effects of toxics. Generally, in other

states, these have followed the guidance

in the TSD. However, EPA believes it is

essential to state that the criteria will

apply at specified design flows for

steady state analyses in today’s rule so

that, where California has not yet

adopted any such design flows, the

criteria proposed today would be

implemented appropriately. The TSD

also recommends the use of three

dynamic models to perform wasteload

allocations. Dynamic wasteload models

do not generally use specific steady

state design flows but accomplish the

same effect by factoring in the

probability of occurrence of stream

flows based on the historical flow

record. For simplicity, only steady state

conditions will be discussed here.

Clearly, if the criteria were implemented

using design flows that are too high, the

resulting toxics controls would not be

fully effective, because the resulting

ambient concentrations would exceed

EPA’s criteria.

In the case of aquatic life, assuming

exceedences occur more frequently than

once in 3 years on the average,

exceedences would result in diminished

vitality of stream ecosystems

characterized by the loss of desired

species. Numeric water quality criteria

should apply at all flows that are equal

to or greater than flows specified below.

The low flow values are:

Aquatic Life

acute criteria (CMC) 1 Q 10 or 1 B

3

chronic criteria (CCC) 7 Q 10 or 4 B

3

Human Health

non-carcinogens 30 Q 5

carcinogens harmonic mean flow

Where:

1 Q 10 is the lowest one day flow with

an average recurrence frequency of

once in 10 years determined

hydrologically;

1 B 3 is biologically based and indicates

an allowable exceedence of once

every 3 years. It is determined by

EPA’s computerized method

(DFLOW model);

7 Q 10 is the lowest average 7

consecutive day low flow with an

average recurrence frequency of

once in 10 years determined

hydrologically;

4 B 3 is biologically based and indicates

an allowable exceedence for 4

consecutive days once every 3

years. It is determined by EPA’s

computerized method (DFLOW

model);

30 Q 5 is the lowest average 30

consecutive day low flow with an

average recurrence frequency of

once in 5 years determined

hydrologically; and the harmonic

mean flow is a long term mean flow

value calculated by dividing the

number of daily flows analyzed by

the sum of the reciprocals of those

daily flows.

EPA is proposing that the harmonic

mean flow be applied with human

health criteria for carcinogens. The

harmonic mean is a standard calculated

statistical value. EPA’s model for human

health effects assumes that such effects

occur because of a long-term exposure

to low concentration of a toxic

pollutant, for example, two liters of

water per day for seventy years. To

estimate the concentrations of the toxic

pollutant in those two liters per day by

withdrawal from streams with a high

daily variation in flow, EPA believes the

harmonic mean flow is the correct

statistic to use in computing such

design flows rather than other averaging

techniques. (For a description of

harmonic means see ‘‘Design Stream

Flows Based on Harmonic Means,’’

Lewis A. Rossman, Jr. of Hydraulics

Engineering, Vol. 116, No. 7, July, 1990.)

Hydrologic assessment methods other

than the hydrologically-based and

biologically-based methods may prove

effective in applying water quality

criteria in specific receiving water

settings.

All waters, whether or not suitable for

such hydrologic calculations but

included in this rule (including lakes,

estuaries, and marine waters), would be

required to attain the criteria proposed

today. Such attainment would be

required to occur at the end of the

discharge pipe, unless the State

authorizes mixing zones. EPA has

approved mixing zone provisions in

Regional Water Quality Control Board

Basin Plans. Where the State intends to

authorize a mixing zone, the criteria

would apply at the locations allowed by

the mixing zone. For example, the

chronic criteria (CCC) would apply at

the defined boundary of the chronic

mixing zone. Discussion of and

guidance on these factors are included

in the revised TSD in Chapter 4.

EPA is aware that the criteria

proposed today for some of the priority

toxic pollutants are at concentrations

less than EPA’s current analytical

detection limits. Analytical detection

limits have never been an acceptable

basis for setting water quality criteria

since they are not related to actual

environmental impacts. The

environmental impact of a pollutant is

based on a scientific determination, not

a measuring technique which is subject

to change. Setting the criteria at levels

that reflect adequate protection tends to

be a forcing mechanism to improve

analytical detection methods. See 1985

Guidelines, page 21. As the methods

improve, limits closer to the actual

criteria necessary to protect aquatic life

and human health became measurable.

The Agency does not believe it is

appropriate to propose or promulgate

criteria that are not sufficiently

protective.

EPA does believe, however, that the

use of analytical detection limits are

appropriate for determining compliance

with National Pollutant Discharge

Elimination System (NPDES) permit

limits. This view of the role of detection

limits was articulated in guidance for

translating dioxin criteria into NPDES

permit limits, which is the principal

method used for water quality standards

enforcement. See ‘‘Strategy for the

Regulation of Discharges of PHDDs and

PHDFs from Pulp and Paper Mills to

Waters of the U.S.’’ Memorandum from

the Assistant Administrator for Water to

the Regional Water Management

Division Directors, May 21, 1990. This

guidance presents a model for

addressing toxic pollutants which have

criteria less than current detection

limits. This guidance is equally

applicable to other priority toxic

pollutants with criteria less than current

detection limits. The guidance explains

that standard analytical methods may be

used for purposes of determining

compliance with permit limits, but not

for purposes of establishing water

quality criteria or permit limits. Under

the CWA, analytical methods are

appropriately used in connection with

NPDES permit limit compliance

determinations. Because of the function

of water quality criteria, EPA has not

considered the sensitivity of analytical

methods in deriving the criteria

proposed today.

EPA has proposed 40 CFR

131.38(c)(3) to determine when

freshwater or saltwater aquatic life

criteria apply. This provision

incorporates a time parameter to better
42184 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

define the critical condition. The

structure of the paragraph is to establish

applicable rules and to allow for sitespecific exceptions where the rules are

not consistent with actual field

conditions. Because a distinct

separation generally does not exist

between freshwater and saltwater

aquatic communities, EPA is

establishing the following: (1) The

freshwater criteria apply at salinities of

1 part per thousand and below at

locations where this occurs 95% or

more of the time; (2) saltwater criteria

apply at salinities of 10 parts per

thousand and above at locations where

this occurs 95% more of the time; and

(3) at salinities between 1 and 10 parts

per thousand the more stringent of the

two apply unless EPA approves the

application of the freshwater or

saltwater criteria based on an

appropriate biological assessment. The

percentiles included here were selected

to minimize the chance of overlap, that

is, one site meeting both criteria.

Determination of these percentiles can

be done by any reasonable means such

as interpolation between points with

measured data or by the application of

calibrated and verified mathematical

models (or hydraulic models). It is not

EPA’s intent to require actual data

collection at particular locations.

In the brackish water transition zones

of estuaries with varying salinities, there

generally will be a mix of freshwater

and saltwater species. Generally,

therefore, it is reasonable for the more

stringent of the freshwater or saltwater

criteria to apply. In evaluating

appropriate data supporting the

alternative set of criteria, EPA will focus

on the species composition as its

preferred method. This assignment of

criteria for fresh, brackish and salt

waters was developed in consultation

with EPA’s research laboratories at

Duluth, Minnesota and Narragansett,

Rhode Island. The Agency believes such

an approach is consistent with field

experience.

Subsection (d) lists the designated

water and use classifications for which

the proposed criteria apply. The criteria

are applied to the beneficial use

designations adopted by the State of

California; EPA has not promulgated

any new use classifications in this rule.

Exceedence Frequency: In a water

quality criterion for aquatic life, EPA

recommends an allowable frequency for

excursions of the criteria. See 1985

Guidelines, pages 11–13. This allowable

frequency provides an appropriate

period of time during which the aquatic

community can recover from the effect

of an excursion and then function

normally for a period of time before the

next excursion. An excursion is defined

as an occurrence of when the average

concentration over the duration of the

averaging period is above the CCC or the

CMC. As ecological communities are

naturally subjected to a series of

stresses, the allowable frequency of

pollutant stress may be set at a value

that does not significantly increase the

frequency or severity of all stresses

combined. See also TSD, Appendix D.

In addition, providing an allowable

frequency for exceeding the criterion

recognizes that it is not generally

possible to assure that criteria are never

exceeded. (TSD, page 36.)

Based on the available data, EPA is

proposing that the acute criterion for a

pollutant be exceeded no more than

once in three years on the average. EPA

is also proposing that the chronic

criterion for a pollutant be exceeded no

more than once in three years on the

average. EPA acknowledges that the

State may develop allowable

frequencies that differ from these

allowable frequencies, so long as they

are scientifically supportable, but

believes that these allowable

frequencies are protective of the

designated uses.

The use of aquatic life criteria for

developing water quality-based effluent

limits in permits requires the permitting

official to use an appropriate wasteload

allocation model. (TSD, Appendix D–6.)

As discussed above, there are generally

two methods for determining design

flows, the hydrologically-based method

and the biologically-based method.

The biologically-based method

directly uses the averaging periods and

frequencies specified in the aquatic life

criteria for determining design flows.

(TSD, Appendix. D–8.) Because the

biologically-based method calculates the

design flow directly from the duration

and allowable frequency, it most

accurately provides the allowed number

of excursions. The hydrologically based

method applies the CMC at a design

flow equal to or equivalent to the 1Q10

design flow (i.e., the lowest one-day

flow with a recurrence frequency of one

year in ten years), and applies the CCC

at the 7Q10 design flow (i.e., the lowest

seven day flow with a recurrence

frequency of one year in ten years).

EPA established a three year

allowable frequency in the NTR. In

settlement of the litigation on the NTR,

EPA stated that it was in the midst of

conducting, sponsoring, or planning

research aimed at addressing scientific

issues related to the basis for and

application of water quality criteria and

mentioned the issue of allowable

frequency. See Partial Settlement

Agreement in American Forest and

Paper Ass’n, Inc. et al. v. U.S. EPA

(Consolidated Case No. 93–0694 (RMU)

D.D.C. To that end, EPA is reevaluating

issues raised about allowable frequency

as part of its work in revising the 1985

Guidelines.

In addition, EPA received public

comment on the allowable frequency

incorporated into the amendments to

the NTR. These comments argued that a

once every three years on the average

excursion frequency for 4-day average

concentrations, or a 7Q10 design flow

for chronic criteria, was unnecessarily

restrictive. For chronic criteria,

commenters noted that EPA has

approved use of a 30Q3 design in

Colorado, a 30Q5 design flow in

Maryland, and a 1 percent exceedance

frequency in Pennsylvania. Comments

recommended that EPA use the 30Q5

design flow for chronic criteria.

EPA recognizes that additional data

concerning (a) the probable frequency of

lethal events for an assemblage of taxa

covering a range of sensitivities to

pollutants, (b) the probable frequency of

sublethal effects for such taxa, (c) the

differing effects of lethal and sublethal

events in reducing populations of such

taxa, and (d) the time needed to replace

organisms lost as a result of toxicity,

may lead to further refinement of the

allowable frequency value. Due to lack

of available resources, EPA has not yet

completed this work. Until this work is

complete, EPA believes that the three

year allowable frequency represents a

value in the reasonable range for this

parameter.

3. Implementation

Once the applicable designated uses

and water quality criteria for a water

body are determined, under the

National Pollutant Discharge

Elimination System (NPDES) program,

discharges to the water body must be

characterized and the permitting

authority must determine the need for

permit limits. If a discharge causes, has

the reasonable potential to cause, or

contributes to an excursion of a numeric

or narrative water quality criteria, the

permitting authority must develop

permit limits as necessary to meet water

quality standards. These permit limits

are water quality-based effluent

limitations or WQBELs. The terms

‘‘cause,’’ ‘‘reasonable potential to

cause,’’ and ‘‘contribute to’’ are the

terms in the NPDES regulations for

conditions under which water qualitybased permit limits are required. See 40

CFR 122.44(d)(1).

Total Maximum Daily Loads (TMDLs):

If a water quality problem is identified,

a wasteload allocation (WLA) based on

an existing total maximum daily load
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42185

(TMDL) may be established. A TMDL is

the sum of the individual WLAs for

point sources and load allocations (LA)

for nonpoint sources of pollution and

natural background sources, tributaries,

or adjacent segments. WLAs represent

that portion of a TMDL that is allocated

to existing and future point sources so

that surface water quality is protected at

all flow conditions.

The TMDL process uses water quality

analyses to predict water quality

conditions and pollutant

concentrations. Point source and

nonpoint source allocations are

established so that predicted receiving

water concentrations do not exceed

water quality standards. TMDLs and

WLAs/LAs should be established at

levels necessary to attain and maintain

the applicable narrative and numerical

water quality standards, with seasonal

variations and a margin of safety that

takes into account any lack of

knowledge concerning the relationship

between point and nonpoint source

loadings and water quality.

The CWA under section 303(d),

requires the establishment of TMDLs for

stream segments listed as ‘‘water quality

limited’’ pursuant to section 303(d). In

such segments, water quality does not

meet applicable water quality standards

and/or is not expected to meet

applicable water quality standards. A

TMDL includes a determination of the

amount of a pollutant, or property of a

pollutant, from point, nonpoint, and

natural background sources, including a

margin of safety, that may be discharged

to a water-quality limited water body.

During California’s recent set of Task

Force meetings concerning the

readoption of statewide water quality

control plans, the Permitting Task Force

made several recommendations

concerning the TMDL process. Since the

TMDL process can be significantly labor

and data intensive, a recommendation

was made to create collaborative efforts

to establish TMDLs on water quality

limited water bodies. This collaborative

effort by dischargers, the State, EPA,

and other stakeholders, could distribute

work and associated costs between the

interested parties, as well as shorten the

overall time necessary to complete the

analyses. Another recommendation was

to allow innovative alternatives to

traditional ‘‘pounds per day’’ TMDLs.

EPA supports these Task Force

recommendations for the State of

California.

Within the TMDL framework, EPA

encourages innovative approaches such

as effluent trading as a method to attain

and/or maintain water quality

standards. Effluent trading allows

sources that can control pollutants

beyond compliance with current

requirements to sell or trade credits for

its excess reduction to another source

unable to control its own pollutants as

effectively or as efficiently. The goal of

an effluent trading program is to achieve

similar or improved environmental

results in a more cost-effective manner

than under current regulatory

structures. EPA’s most current policy on

effluent trading is summarized in the

‘‘Policy Statement for Effluent Trading

in Watersheds’’ which was issued in

January of 1996 and which reiterates

President Clinton’s commitment to

effluent trading as expressed in the

March 16, 1995 report on ‘‘Reinventing

Environmental Regulation.’’ The Policy

states that ‘‘EPA will work cooperatively

with key stakeholders to find sensible,

innovative ways to meet water quality

standards quicker and at less cost than

traditional approaches alone.’’ The

policy outlines several different types of

trades that may take place. These trades

include but are not limited to the

following: (1) Intra-plant trading

between outfalls within one facility; (2)

pretreatment trading between indirect

industrial point sources that discharge

to a POTW; (3) point to point source

trading, point to nonpoint source

trading, and nonpoint to nonpoint

source trading.

Interim Permit Limits: The State’s

Permitting Task Force also discussed at

length the issue of interim numeric

permit limits when a TMDL/WLA/LA or

other special study is underway but not

completed. The Task Force made

several recommendations regarding how

to determine these interim limits. The

Task Force recommended that interim

numeric limits be calculated based on

past performance and future

uncertainty. Past performance and

future uncertainty can be considered as

factors in determining interim permit

limits; however, permitting authorities

may consider other factors, particularly

factors concerning the water quality of

the receiving water body and the overall

goal to attain the water quality standard.

The Task Force also recommended that

a specific method be followed in

determining interim limits and ‘‘trigger’’

concentrations above which corrective

action would be necessary. EPA

supports innovative ideas such as these,

however, the State as the permitting

authority has broad discretion in

determining how interim permit limits

should be ascertained in different

situations. EPA supports the State’s

consideration of stakeholder Task Force

recommendations to help deal with

these controversial and complex issues.

Mixing Zones: Another important

issue discussed during the State’s Task

Force meetings was the issue of mixing

zones. A mixing zone is a limited area

or volume of water where initial

dilution of a discharge takes place and

where water quality standards can be

exceeded. Mixing zones have been

applied in the water quality standards

program since its inception. The present

water quality standards regulation

allows states to adopt acute and chronic

mixing zones as a matter of state

discretion, so long as the state’s mixing

zone protects the designated uses.

A mixing zone should be established

to ensure that the zone will not impair

the integrity of the water body as a

whole, the zone will not cause lethality

to passing organisms, and, considering

likely pathways of exposure, that there

are no significant human health risks.

For application of two-number aquatic

life criteria, as proposed in this rule,

there may be up to two types of mixing

zones. In the zone immediately

surrounding the outfall, neither the

acute nor the chronic criterion is met.

The acute criterion is met at the edge of

this zone. In the next mixing zone, the

acute, but not the chronic, criterion is

met. The chronic criterion is met at the

edge of the second mixing zone.

However, since both aquatic life and

human health criteria are proposed in

today’s rule, the State may establish

independent mixing zone policies for

each. For any particular pollutant from

any particular discharge, the magnitude,

frequency, duration and mixing zone

associated with each of the type of

criteria may determine which one most

limits the allowable discharge.

Several California Regional Water

Quality Control Boards have adopted

mixing zone provisions in their

respective Basin Plans. These mixing

zone provisions can be applied to

discharges to water bodies to which

water quality standards based on the

criteria contained in this proposed rule

will apply when these criteria are

promulgated final.

Variances: Another important

procedure to assist the State in

effectively implementing water quality

standards in the NPDES program is the

water quality standard variance

procedure. The State may adopt a

statewide policy (or Regional Boards

may adopt Basin-wide policies) to allow

for water quality standard variances to

individual dischargers. The variance

policy would allow the State or

Regional Board to grant a variance to an

individual permittee from a water

quality standard which is the basis of a

water quality-based effluent limitation

in a permit. The variance would allow

the permittee time to achieve reasonable

progress towards attaining a specific
42186 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

water quality-based effluent limitation,

without violating CWA section 402(a)(1)

which requires that NPDES permittees

meet all applicable water quality

standards.

A permittee applying for a variance

may not be a new or recommencing

discharger. The water quality standard

variance applies only to the permittee

requesting the variance and only to the

pollutant or pollutants specified in the

variance. A variance does not effect the

corresponding water quality standard

for the water body receiving the

discharge. Variances are designed to

preserve the underlying water quality

standard over the long term, while

providing flexibility to individual

dischargers in complying with permit

limits based on the standards. When a

variance is granted, the discharger is

assured compliance during the term of

a variance, as long as all variance

conditions are met.

A State-adopted variance policy will

be approved by the EPA if it is

consistent with the substantive

requirements set out at 40 CFR Part 131

for removing a designated use.

Specifically, the State’s policy must

require the inclusion of a demonstration

that a water quality standard is

unattainable, based on one or more of

the following grounds:

1. Naturally occurring pollutant

concentrations prevent the attainment of

the water quality standard;

2. Natural, ephemeral, intermittent or

low flow conditions or water levels

prevent the attainment of the water

quality standard, unless these

conditions may be compensated for by

the discharge of sufficient volume of

effluent to enable the standard to be met

without violating State water

conservation requirements;

3. Human-caused conditions or

sources of pollution prevent the

attainment of the water quality standard

and cannot be remedied, or would cause

more environmental damage to correct

than to leave in place;

4. Dams, diversions or other types of

hydrologic modifications preclude the

attainment of a water quality standard,

and it is not feasible to restore the water

body to its original condition or to

operate such modification in a way that

would result in the attainment of the

standard;

5. Physical conditions related to the

natural features of the water body, such

as the lack of a proper substrate cover,

flow, depth, pools, riffles, and the like,

unrelated to chemical water quality,

preclude attainment of the water quality

standard; or

6. Controls more stringent than those

required by CWA sections 301(b) and

306 would result in substantial and

widespread economic and social

impact.

EPA will approve a State policy

providing for variances if the policy

includes the following provisions:

1. The State will include each

individual variance as part of its water

quality standard or water quality plan;

2. The variance will include

documentation that treatment more

advanced than that required by CWA

section 301(b) and 306 has been

carefully considered, and that

alternative effluent control strategies

have been evaluated;

3. The underlying, more stringent

criterion will be maintained and will be

binding on all other dischargers;

4. The discharger who will be given

a variance for one particular constituent

will be required to meet the applicable

criteria for other constituents;

5. The variance will be granted for a

specific period of time and must be

rejustified upon expiration, but at least

every three years;

6. Reasonable progress will be made

towards meeting the underlying

standards;

7. The variance will not likely

jeopardize the continued existence of

any threatened or endangered species

listed under Section 4 of the

Endangered Species Act or result in the

destruction or adverse modification of

such species’ critical habitat; and

8. The variance will be subjected to

public notice, comment, and hearing.

See CWA section 303(c)(1) and 40 CFR

131.20. The public notice should

contain a clear description of the impact

of the variance upon achieving the

water quality standard in the water

body.

Once a variance has been approved by

the State, it must be submitted to EPA

for approval. If this proposed rule is still

in effect, as with the State adoption of

site-specific criteria, EPA would have to

undertake rulemaking to make the

necessary changes to this rule. Further

guidance on variance policies is

provided in EPA’s 1994 Water Quality

Standards Handbook, Chapters 2 and 5

(EPA 823–B–94–005a, August 1994).

EPA, however, cautions California

and the public that promulgation of this

federal rule removes most of the

flexibility available to the State for

modifying its standards on a dischargerspecific or stream-specific basis. For

example, variances and site-specific

criteria development are actions

sometimes adopted by states. These are

optional policies under terms of the

federal water quality standards

regulation. Except for the water-effect

ratio procedure for certain metals, EPA

has not incorporated either optional

policy, in general, in this proposed

rulemaking, that is, EPA has not

generally authorized State modifications

of federal water quality standards. Each

of these types of modifications will, in

general, require federal rulemaking on a

case-by-case basis to change the federal

rule. Because of the time consuming

nature of reviewing such requests,

limited federal resources, and the need

for the Agency to move into other

priority program areas in establishing

environmental controls, EPA alerts

California and the public that a prompt

Agency response is unlikely. The best

course of action, if such provisions are

desired, is for the State to adopt its own

standards and take advantage, if it so

chooses, of the flexibility offered by

these optional provisions.

4. Wet Weather Flows

Questions have already arisen

concerning the applicability of these

proposed criteria to discharges from wet

weather point sources. A wet weather

point source means any discernible

confined and discrete conveyance from

which pollutants are, or may be,

discharged as the result of a wet weather

event. For purposes of this discussion,

discharges from wet weather point

sources shall include only: discharges of

storm water from a municipal separate

storm sewer as defined at 40 CFR

122.26(b)(8); storm water discharge

associated with industrial activity as

defined at 40 CFR 122.26(b)(14);

discharges of storm water and sanitary

wastewaters (domestic, commercial, and

industrial) from a combined sewer

overflow; or any storm water discharge

for which a permit is required under

section 402(p) of the CWA. A storm

water discharge associated with

industrial activity which is mixed with

process wastewater is not considered a

wet weather point source.

National Pollutant Discharge

Elimination System (NPDES) permits for

wet weather point source discharges

must include limits necessary to

implement applicable water quality

standards, through application of water

quality-based effluent limitations or

WQBELs. Section 301(b)(1)(C) of the

CWA, 33 U.S.C. 1311(b)(1)(C); see also

Memorandum of E. Donald Elliot,

Assistant Administrator and General

Counsel, to Nancy J. Marvel, Region 9,

dated January 9, 1991. When this

rulemaking is complete, these criteria

will be used to determine water quality

standards in California and will

therefore be the basis of WQBELs in

NPDES permits for wet weather point

sources. However, EPA recognizes that

it is commonly infeasible to express
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42187

WQBELs as numeric limits for wet

weather discharges and that in such

cases best management practices

(‘‘BMPs’’) may serve as WQBELs. See,

e.g., NRDC v. Costle, 568 F. 2d 1369,

1380 (D.C. Cir. 1977) (‘‘when numeric

effluent limitations are infeasible, EPA

may issue permits with conditions

designed to reduce the level of effluent

discharges to acceptable levels.’’); NRDC

v. U.S. EPA, 822 F. 2d 104, 122 (D.C.

Cir. 1987) (‘‘* * * Congress has seen fit

to empower EPA to prescribe as wide a

range of permit conditions as the agency

deems appropriate in order to assure

compliance with applicable effluent

limits.’’). It is therefore anticipated that

WQBELs, including those necessary to

meet the criteria set forth in this

proposed rule, will be expressed as

BMPs in wet weather discharges’

NPDES permits, when the permitting

authority determines that it is infeasible

to express WQBELS as numeric limits.

5. Schedules of Compliance

A compliance schedule refers to an

enforceable sequence of interim

requirements in a permit leading to

ultimate compliance with water qualitybased effluent limitations or WQBELs in

accordance with the CWA. The

proposed authorizing compliance

schedule provision authorizes, but does

not require, the permit issuing authority

in the State of California to include such

compliance schedules in permits under

appropriate circumstances. The State of

California is authorized to administer

the National Pollutant Discharge

Elimination System (NPDES) program

and may exercise its discretion when

deciding if a compliance schedule is

justified because of the technical or

financial (or other) infeasibility of

immediate compliance.

This authorizing compliance schedule

provision is included in the proposed

rule because of the potential for existing

dischargers to have new or more

stringent effluent limitations, under the

final rule, for which immediate

compliance would not be possible or

practicable.

New and Existing Dischargers: The

proposed provision allows compliance

schedules only for an ‘‘existing

discharger’’ which is defined as any

discharger which is not a ‘‘new

California discharger.’’ A ‘‘new

California discharger’’ includes ‘‘any

building, structure, facility, or

installation from which there is, or may

be, a ‘discharge of pollutants’, the

construction of which commenced after

the effective date of this regulation.’’

These definitions are modelled after the

existing 40 CFR 122.2 definitions for

parallel terms, but with a cut-off date

modified to reflect this rule. Only ‘‘new

California dischargers’’ are required to

comply immediately upon

commencement of discharge with

effluent limitations derived from the

criteria in this rule.

For ‘‘existing dischargers’’ whose

permits were reissued or modified to

contain new or more stringent

limitations based upon certain water

quality requirements, the permit could

allow up to five years to comply with

such limitations. The provision applies

to new or more stringent effluent

limitations based on the criteria in this

EPA rule.

EPA has included ‘‘increasing

dischargers’’ within the category of

‘‘existing dischargers’’ since ‘‘increasing

dischargers’’ are existing facilities with

a change—an increase—in their

discharge. Such facilities may include

those with seasonal variations.

‘‘Increasing dischargers’’ will already

have treatment systems in place for their

current discharge, thus, they have less

opportunity than a new discharger does

to design and build a new treatment

system which will meet new water

quality-based requirements for their

changed discharge. Allowing existing

facilities with an increasing discharge a

compliance schedule will avoid placing

the discharger at a competitive

disadvantage vis-a-vis other existing

dischargers who are eligible for

compliance schedules.

The proposed rule does not prohibit

the use of a short-term ‘‘shake down

period’’ for new California dischargers

as is provided for new sources or new

dischargers in 40 CFR 122.29(d)(4).

These regulations require that the owner

or operator of (1) a new source; (2) a

new discharger (as defined in 40 CFR

122.2) which commenced discharge

after August 13, 1979; or (3) a

recommencing discharger shall install

and implement all pollution control

equipment to meet the conditions of the

permit before discharging. The facility

must also meet all permit conditions in

the shortest feasible time (not to exceed

90 days). This shake-down period is not

a compliance schedule. This approach

may be used to address violations which

may occur during a new facility’s startup, especially where permit limits are

water quality-based and biological

treatment is involved.

The burden of proof to show the

necessity of a compliance schedule is on

the discharger, and the discharger must

request approval from the permit

issuing authority for a schedule of

compliance. The discharger should

submit a description of the minimum

required actions or evaluations that

must be undertaken in order to comply

with the new or more restrictive

discharge limits. Dates of completion for

the required actions or evaluations

should be included, and the proposed

schedule should reflect the shortest

practicable time to complete all

minimum required actions.

Duration of Compliance Schedules:

EPA believes that compliance schedules

of three years or less will be sufficient

to allow facilities to make the changes

necessary to meet new or more

restrictive discharge requirements in

most cases. Such compliance periods

are consistent with analogous

provisions of the CWA including

sections 301(b)(2) and 304(l). For

example, section 301(b)(2)(C)—(F) of the

Act provides that various technologybased effluent limitations shall be

complied with as expeditiously as

possible but no later than three years

after effluent limitations are

promulgated. Similarly, section 304(l)

provides that sources shall comply with

individual control strategies (waterquality based requirements) within

three years.

However, the Agency also recognizes

the concerns of dischargers regarding

the amount of time and resources in

some cases that may be needed for

implementing certain new or complex

state-of-the-art treatment technologies

and other pollution prevention

programs. The Agency recognizes that

evaluation, design and implementation

of facility-wide comprehensive

pollution prevention control strategies

involving product substitution, process

line changes, new piping, revised waste

handling, etc. may require more than

three years at large facilities. In

addition, EPA is aware that the

technical and administrative process of

modifying and implementing revised

requirements for numerous industrial

users at publicly owned treatment

works, as well as planning, budgeting,

and undertaking significant new

construction to change treatment

processes at a municipal treatment

works, may require more than three

years.

Therefore, the proposed rule provides

that compliance schedules may provide

for up to five years to meet new or more

stringent effluent limitations in those

limited circumstances where the

permittee can demonstrate to the permit

authority that such an extended

schedule is warranted. EPA emphasizes

its belief that in most situations less

than three years will be required; EPA

believes that permit authorities should

consider shorter compliance schedules

wherever possible or alternatively, not

allow compliance schedules where

unnecessary. This provision should not
42188 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

be considered a default compliance

schedule duration for existing facilities.

In instances where dischargers wish

to conduct toxicological studies, analyze

results, and adopt and implement new

or revised water quality-based effluent

limitations, EPA believes that five years

is sufficient time within which to

complete this process.

Under this proposal, where a

schedule of compliance exceeds one

year, interim requirements are to be

specified and interim progress reports

are to be submitted at least annually to

the permit issuing authority, in at least

one-year time intervals.

The proposed rule allows all

compliance schedules to extend up to a

maximum duration of five years, which

is the maximum term of any NPDES

permit. See 40 CFR 122.46. The

discharger’s opportunity to obtain a

compliance schedule occurs when the

existing permit for that discharge is

issued, reissued or modified, whichever

is sooner. Such compliance schedules,

however, cannot be extended to any

indefinite point of time in the future

because no final compliance date for

WQBELs based upon this rule shall be

more than ten years from the effective

date of the rule. Thus, delays in

reissuing expired permits (including

those which continue in effect under

applicable NPDES regulations) cannot

indefinitely extend the period of time

during which a compliance schedule is

in effect. Ten years allows for inclusion

of the single maximum five-year

compliance schedule in a permit which

is reissued five years after the effective

date of this rule (having been previously

issued without WQBELS using today’s

proposed criteria on the eve of the

effective date of this rule).

EPA recognizes that where a permit is

modified during the permit term, and

the permittee needs the full five years to

comply, the five-year schedule may

extend beyond the term of the modified

permit. In such cases, the rule allows for

the modified permit to contain a

compliance schedule with an interim

limit by the end of the permit term.

When the permit is reissued, the permit

authority may extend the compliance

schedule in the next permit, provided

that, taking into account the amount of

time allowed under the previous permit,

the entire compliance schedule shall not

exceed five years. Final permit limits

and compliance dates will be included

in the record for the permit. Final

compliance dates must occur within

five years from the date of permit

issuance, reissuance, or modification,

unless additional or less time is

provided for by law.

Antibacksliding: EPA wishes to

address the potential concern over

antibacksliding where revised permit

limits based on new information are the

result of the completion of additional

studies. The Agency’s interpretation of

the CWA is that the antibacksliding

requirements of section 402(o) of the

CWA do not apply to revisions to

effluent limitations made before the

scheduled date of compliance for those

limitations.

State Compliance Schedule

Provisions: EPA supports the State in

adopting a statewide provision

independent of or as part of the current

effort to readopt statewide water quality

control plans, or in adopting individual

basin-wide compliance schedule

provisions through its nine Regional

Water Quality Control Boards

(RWQCBs). The State and RWQCBs

have broad discretion to adopt a

provision, including discretion on

reasonable lengths of time for final

compliance with WQBELs. EPA

recognizes that practical time frames

within which to set interim goals may

be necessary to achieve meaningful,

long-term improvements in water

quality in California.

At this time, at least one RWQCB has

adopted an authorizing compliance

schedule provision as an amendment to

its Basin Plan during its last triennial

review process. If EPA includes an

authorizing compliance schedule

provision in the final rule, any

appropriately adopted Basin Plan

amendment concerning a compliance

schedule provision would also be

effective for the Basin.

G. Executive Order (E.O.) 12866,

Regulatory Planning and Review

Under Executive Order 12866, [58 FR

51,735 (October 4, 1993)] the Agency

must determine whether the regulatory

action is ‘‘significant’’ and therefore

subject to Office of Management and

Budget (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 entitlements, 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.

It has been determined that this rule

is not a ‘‘significant regulatory action’’

under the terms of Executive Order

(E.O.) 12866 and is therefore not subject

to OMB review. The proposed rule

establishes ambient water quality

criteria which, by themselves, do not

directly impose economic impacts.

When these criteria are combined with

the State-adopted designated uses for

inland surface waters, enclosed bays

and estuaries, water quality standards

will be created. EPA acknowledges that

there may be a cost to some dischargers

for complying with new water quality

standards after those standards are

translated into specific National

Pollutant Discharge Elimination System

(NPDES) permit limits by the State.

Consistent with the intent of E.O. 12866,

EPA prepared an Economic Analysis

(EA). Since the State has significant

flexibility and discretion in how it

chooses to implement standards within

the NPDES permit program, the EA by

necessity includes many assumptions

about how the State will implement the

water quality standards. These

assumptions are based on a combination

of EPA guidance and current permit

conditions for the facilities examined in

this analysis. (This is appropriate

because if the State does not adopt

statewide implementation provisions,

the rule-based water quality standards

would be implemented using existing

State basin plan provisions, and EPA

regulations and guidance.) A more

precise measure of costs and benefits

may not be known until the State adopts

its implementation provisions. To

account for the uncertainty of these

assumptions, this analysis estimates a

wide range of costs and benefits. By

completing the EA, EPA intends to

inform the public about how entities

might be affected by implementation of

rule-based water quality standards in

the NPDES permit program.

1. Baselines

In order to estimate the costs and

benefits, an appropriate baseline must

be established. The baseline is the

starting point for measuring incremental

costs and benefits of a proposed

regulation. The baseline is established

by assessing what would occur in the

absence of the proposed regulation. EPA

estimated the incremental costs and

benefits of potential State

implementation of water quality

standards based on the criteria
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42189

contained in today’s proposed rule

using two different models which used

different baselines.

The first model used a baseline that

results in no incremental impacts. This

baseline assumes that, in the absence of

this rule, the State would, pursuant to

the NPDES regulations, 40 CFR

122.44(d)(iv), rely on the Regional Board

narrative standards to establish numeric

water quality-based effluent limits in

permits. These limits could be based on

the latest EPA 304(a) criteria—the same

information upon which today’s

proposed criteria are based, or

supplemented where necessary by other

relevant information. Under this

scenario, no impacts would be

attributed permit limits based on

implementation of water quality

standards using the criteria contained in

today’s proposed rule, since the analysis

presumes that the State, in the absence

of this rule, would implement effluent

limits that are as stringent as those that

would be implemented using water

quality standards based on today’s

proposed criteria.

The baseline used in the second

model assumes that in the absence of

the rule, current permit requirements

and current effluent concentrations

would continue into the future. This

model generally uses a baseline of

current permit limits to develop a high

scenario cost estimate and a baseline of

current effluent concentrations to

develop a low scenario cost estimate.

Using this second model, EPA estimated

a range of potential costs that would

result from State implementation of this

rule’s water quality criteria in NPDES

permits. The costs and benefits sections

that follow summarize the methodology

and results of the analysis using this

baseline.

2. Costs

Under the second model, EPA

assessed the estimated compliance costs

that facilities may incur to meet permit

limits based on the criteria in today’s

proposed rule. The analysis focused on

direct compliance costs such as capital

costs and operation and maintenance

costs (O&M) for end-of-pipe pollution

control, indirect source controls,

pollution prevention, monitoring, and

costs of pursuing alternative methods of

compliance.

The population of facilities with

NPDES permits that discharge into

California’s enclosed bays, estuaries and

inland surface waters includes 184

major dischargers and 1,057 minor

dischargers. Of the 184 major facilities,

128 are publicly owned treatment works

(POTWs) and 56 are industrial facilities.

Approximately 2,144 indirect

dischargers designated as significant

industrial users discharge wastewater to

those POTWs. For the direct

dischargers, EPA used a three-phased

process to select a sample of facilities to

represent California dischargers

potentially affected by the State’s

implementation of permit limits based

on the criteria contained in this rule.

The first phase consisted of choosing

three case study areas for which data

was thought to exist. The three case

studies with a total of 5 facilities

included: the South San Francisco Bay

(the San Jose/Santa Clara Water

Pollution Control Plant and Sunnyvale

Water Pollution Control Plant); the

Sacramento River (the Sacramento

Regional Wastewater Treatment Plant);

and the Santa Ana River (the City of

Riverside Water Quality Control Plant

and the City of Colton Municipal

Wastewater Treatment Facility). The

second phase consisted of selecting five

additional major industrial dischargers

to complement the case-study POTWs.

The third and last selection phase

involved selecting 10 additional

facilities to improve the basis for

extrapolating the costs of the selected

sample facilities to the entire population

of potentially affected dischargers. The

additional 10 facilities were selected

such that the group examined: (1) Was

divided between major POTWs and

major industrial discharger categories in

proportion to the numbers of facilities

in the State; (2) gave greater

proportionate representation to major

facilities than minor facilities based on

a presumption that the majority of

compliance costs would be incurred by

major facilities; (3) gave a proportionate

representation to each of four principal

conventional treatment processes

typically used by facilities in specified

industries in California; and (4) was

representative of the proportionate

facilities located within the different

California Regional Water Quality

Control Boards. Within these

constraints, facilities were selected at

random to complete the sample.

For those facilities that were projected

to exceed permit limits based on the

proposed criteria, EPA estimated the

incremental costs of compliance. Using

a decision matrix or flow chart, costs

were developed for two different

scenarios—a ‘‘low-end’’ cost scenario

and a ‘‘high-end’’ cost scenario—to

account for a range of regulatory

flexibility available to the State when

implementing permit limits based on

the proposed water quality criteria. The

assumptions for baseline loadings also

vary over the two scenarios. The lowend scenario generally assumed that

facilities were discharging at the

maximum effluent concentrations taken

from actual monitoring data, while the

high-end scenario generally assumed

that facilities were discharging at their

current effluent limits. The decision

matrix specified assumptions used for

selection of control options, such as

optimization of existing treatment

processes and operations, in-plant

pollutant minimization and prevention,

and end-of-pipe treatment.

Under this second baseline, where

California is not presumed to implement

narrative criteria pursuant to 40 CFR

122.44(d) in all permits, the annualized

potential costs that direct and indirect

dischargers may incur as a result of

State implementation of permit limits

based on water quality standards using

today’s proposed criteria are estimated

to be between $15 million and $87

million. EPA believes that the costs

incurred as a result of State

implementation of these permit limits

will approach the low-end of the cost

range. Costs are unlikely to reach the

high-end of the range because State

authorities are likely to choose

implementation options that provide

some degree of flexibility or relief to

point source dischargers. Furthermore,

cost estimates for both scenarios, but

especially for the high-end scenario,

may be overstated because the analysis

tended to use conservative assumptions

in calculating these permit limits and in

establishing baseline loadings. The

baseline loadings for the high-end were

based on current effluent limits rather

than actual pollutant discharge data.

Most facilities discharge pollutants in

concentrations well below current

effluent limits.

Under the low-end cost scenario,

major industrial facilities and POTWs

incur about 65 percent of the potential

costs, and indirect dischargers incur

about 35 percent of the potential costs.

Among the direct dischargers, two

categories incur the majority of potential

costs: POTWs (67 percent), and

Chemical/Petroleum Products (18

percent). The two highest average cost

categories are Metals and Transportation

Equipment ($57,000 per year) and

POTWs ($27,000 per year). About 20

percent of the low-end costs are

associated with pollution prevention

activities, while 70 percent are

associated with pursuing alternative

methods of compliance under the

regulations.

Under the high-end cost scenario,

major industrial facilities and POTWs

incur about 96 percent of the potential

costs, and indirect dischargers incur

about 4 percent of the potential costs.

Among the direct dischargers, three

categories incur the majority of potential
42190 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

costs—POTWs (70 percent), Chemical/

Petroleum Products (18 percent), and

Metals and Transportation Equipment (8

percent). The average annual per plant

cost for different industry categories

ranges from zero to $816,000. The two

highest average cost categories under

the second baseline are Metals and

Transportation Equipment ($816,000

per year) and Chemical/Petroleum

Products ($678,000 per year). The shift

in proportion of potential costs between

direct and indirect dischargers is due to

the assumption that more direct

dischargers will use end-of-pipe

treatment under the high-end scenario.

Thus, a smaller proportion of indirect

dischargers (10 percent) are impacted

under the high-end scenario, since

municipalities would add end-of-pipe

treatment which would reduce the need

for controls from indirect discharges.

About 90 percent of the costs are for

capital and operating costs for

wastewater treatment while about 10

percent of the high-end costs are

associated with pollution prevention

activities.

Cost-Effectiveness: Cost-effectiveness

is estimated in terms of the cost of

reducing the loadings of toxic pollutants

from point sources. The costeffectiveness is derived by dividing the

annual costs of implementing permit

limits based on water quality standards

using today’s proposed criteria by the

toxicity-weighted pounds (poundequivalents) of pollutants removed.

Pound-equivalents are calculated by

multiplying pounds of each pollutant

removed by the toxic weight (based on

the toxicity of copper) for that pollutant.

Based on this analysis, State

implementation of permit limits based

on today’s proposed criteria would be

responsible for the reduction of about

630,000 to 7 million toxic poundequivalents per year, or 18 to 30 percent

of the toxic-weighted baseline for the

low- and high-end scenarios,

respectively. The cost-effectiveness of

the scenarios ranges from $8 to $12 per

pound-equivalent.

3. Benefits

The benefits analysis is intended to

provide insight into both the types and

potential magnitude of the economic

benefits expected as a result of

implementation of water quality

standards based on today’s proposed

criteria. To the extent feasible, empirical

estimates of the potential magnitude of

the benefits are developed and then

compared to the estimated costs of

implementing water quality standards

based on today’s proposed criteria.

To perform a benefits analysis, the

types or categories of benefits that apply

need to be defined. EPA relied on a set

of benefits categories that typically

applies to changes in the water resource

environment. Benefits were categorized

as either use benefits or passive

(nonuse) benefits depending on whether

or not they involve some source of

direct use of, or contact with, the

resource. The most prominent use

benefit categories are those related to

recreational fishing, boating, and

swimming. Another use benefit category

of significance is human health risk

reduction. Human health risk

reductions can be realized through

actions that reduce human exposure to

contaminants such as exposure through

the consumption of fish containing

elevated levels of pollutants. Passive use

benefits are those improvements in

environmental quality that are valued

by individuals apart from any use of the

resource in question.

Benefits estimates were derived in

this study using an approach in which

benefits of discrete large-scale changes

in water quality beyond present day

conditions were estimated wherever

feasible. A share of those benefits was

then apportioned to implementation of

water quality standards based on today’s

proposed criteria. The apportionment

estimate was based on a three-stage

process:

First, EPA assessed current total

loadings from all sources that are

contributing to the toxics-related water

quality problems observed in the State.

This defines the overall magnitude of

loadings. Second, the share of total

loadings that are attributable to sources

that would be controlled through

implementation of water quality

standards based on today’s proposed

criteria was estimated. Since this

analysis was designed to focus only on

those controls imposed on point

sources, this stage of the process

entailed estimating the portion of total

loadings originating from point sources.

Third, the percentage reduction in

loadings expected due to

implementation of today’s proposed

criteria was estimated and then

multiplied by the share of point source

loadings to calculate the portion of

benefits that could be attributed to

implementation of water quality

standards based on today’s proposed

criteria.

Total monetized annual benefits were

estimated in the range of $1.5 to $51.7

million. By category, annual benefits

were $0.0 to $5.3 million for avoided

cancer risk, $0.6 to $10.1 million for

recreational angling, and $0.9 to $36.3

million for passive use benefits.

There are numerous categories of

potential or likely benefits that have

been omitted from the quantified and

monetized benefit estimates. In terms of

potential magnitudes of benefit, the

following are likely to be significant

contributors to the underestimation of

the monetized values presented above:

• Improvements in water-related (instream and near stream) recreation apart

from fishing. The omission of potential

motorized and nonmotorized boating,

swimming, picnicking, and related instream and stream-side recreational

activities from the benefits estimates

could contribute to an appreciable

underestimation of total benefits. Such

recreational activities have been shown

in empirical research to be highly

valued, and even modest changes in

participation and or user values could

lead to sizable benefits statewide. Some

of these activities can be closely

associated with water quality attributes

(notably, swimming). Other recreational

activities may be less directly related to

the water quality improvements, but

might nonetheless increase due to their

association with fishing, swimming, or

other activities in which the

participants might engage.

• Improvements in consumptive and

nonconsumptive land-based recreation,

such as hunting and wildlife

observation. Improvements in aquatic

habitats may lead (via food chain and

related ecologic benefit mechanisms) to

healthier, larger, and more diverse

populations of avian and terrestrial

species, such as waterfowl, eagles, and

otters. Improvements in the populations

for these species could manifest as

improved hunting and wildlife viewing

opportunities, which might in turn

increase participation and user day

values for such activities. Although the

scope of the benefits analysis has not

allowed a quantitative assessment of

these values at either baseline or postrule conditions, it is conceivable that

these benefits could be appreciable.

• Improvements in human health

resulting from reduction of non-cancer

risk. EPA estimated that implementation

of water quality standards based on the

proposed criteria would result in a

reduction of mercury concentrations in

fish tissue and, thus, a reduction in the

hazard from consumption of mercury

contaminated fish. However, EPA was

unable to monetize benefits due to

reduced non-cancer health effects.

• Human health benefits for saltwater

anglers outside of San Francisco Bay

were not estimated. The number of

saltwater anglers outside of San

Francisco Bay is estimated to be 673,000

(based on Huppert, 1989, and U.S. FWS,

1993). The omission of other saltwater

anglers may cause human health

benefits to be underestimated.
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H. Executive Order 12875, Enhancing

the Intergovernmental Partnership

In compliance with Executive Order

(E.O.) 12875 (58 FR 58093, October 28,

1993), EPA has involved the State and

local governments in the development

of this rule. In addition to the significant

participation by State and local

governments, several specific activities

have been carried out. These include:

(1) In early August 1995, EPA

published and distributed to

approximately 4,000 recipients, a fourpage newsletter to notify California

stakeholders that EPA would be

proposing criteria for priority toxic

pollutants, and to invite interested

parties to a public meeting in late

August 1995. The extensive distribution

list came from the State’s interested

stakeholder list developed for its

readoption of water quality control

plans.

(2) On August 24, 1995, EPA held two

public meetings (one on the morning

and one in the afternoon) to discuss the

EPA’ s promulgation with stakeholders

and to answer any specific concerns.

EPA announced that it would meet with

any stakeholder group independently to

discuss their group’s concerns.

(3) Since approximately December of

1993, EPA has been holding public

Focus Group Meetings with the

discharger community and the State to

inform them of EPA’s progress on the

rulemaking and to learn about the

State’s progress on the readoption of its

statewide water quality control plans.

Over the last three and one-half years,

EPA has held over 12 meetings.

(4) In October of 1995, EPA and the

State met with several leaders of the

California’s environmental community

to discuss EPA’s process and progress

on its promulgation project and the

State’s process and progress on its

readoption of statewide water quality

control plans.

(5) In December of 1994 and in March

of 1996, EPA participated in the State’s

public meetings for its readoption of

statewide plans. At each meeting, EPA

gave a short update on its progress of

promulgating toxic criteria and then

answered specific questions from

interested parties.

(6) From April to October of 1995,

EPA participated extensively in all eight

of the State’s Stakeholder Task Force

groups which met monthly to discuss

the State’s readoption of statewide water

quality control plans. When

appropriate, EPA discussed its

promulgation project and answered

stakeholder questions concerning it.

EPA plans to continue this extensive

outreach to its stakeholder groups.

Contact the person listed under the FOR

FURTHER INFORMATION CONTACT section at

the beginning of this preamble for more

information.

I. The Unfunded Mandates Reform Act

of 1995

Title II of the Unfunded Mandates

Reform Act of 1995 (UMRA), establishes

requirements for federal agencies to

assess the effects of their regulatory

actions on State, local, and tribal

governments and the private sector.

Under section 202 of the UMRA, a

federal agency generally must prepare a

written statement, including a costbenefit analysis, for proposed and final

rules with a ‘‘federal mandate’’ 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 any regulation for which a

written statement is needed, section 205

of the UMRA generally requires the

agency to identify and consider a

reasonable number of regulatory

alternatives and adopt the least costly,

most cost-effective 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 an agency

to adopt an alternative other than the

least costly, most cost-effective or least

burdensome alternative if the agency’s

Administrator publishes with the final

rule an explanation why that alternative

was not adopted. Before a federal

agency 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 notifying

potentially affected small governments,

enabling officials of the affected small

governments to have meaningful and

timely input in the development of

regulatory proposals with significant

federal intergovernmental mandates,

and for informing, educating, and

advising small governments on

compliance with the regulatory

requirements. While EPA does not

believe the rule would significantly or

uniquely affect small governments, EPA

has nevertheless made outreach efforts

to small governments as is outlined in

its small government agency plan.

EPA has determined that this rule

does not contain a federal mandate that

may result in expenditures by State,

local, and tribal governments, in the

aggregate, or by the private sector, of

$100 million or more in any one year.

The proposed rule imposes no direct

enforceable duties on the State or any

local government or on the private

sector; rather, this rule proposes

ambient water quality criteria which,

when combined with State-adopted

designated uses, will create water

quality standards for those water bodies

with adopted uses. The State may use

these resulting water quality standards

in implementing its existing water

quality control programs. Today’s

proposed rule does not directly regulate

or affect any entity and, therefore, is not

subject to the requirements of sections

202 and 205 of the UMRA.

As discussed above, EPA has

examined the range of possible indirect

impacts from State implementation of

the rule in the National Pollutant

Discharge Elimination System (NPDES)

permit program. As discussed above in

Section G, the State has significant

flexibility in establishing and

implementing NPDES permit limits. As

a result, the analysis makes many

assumptions concerning how the State

will implement the water quality

standards in the NPDES permit

program. These assumptions are

discussed in the analysis. The actual

effect on any group of stakeholders is

greatly dependent on the State’s

implementation.

J. The Regulatory Flexibility Act

Under the Regulatory Flexibility Act

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

agencies generally are required to

conduct an initial regulatory flexibility

analysis (IRFA) describing the impact of

the regulatory action on small entities as

part of a proposed rulemaking.

However, under section 605(b) of the

RFA, if the Administrator for the agency

certifies that the proposed rule will not

have a significant economic impact on

a substantial number of small entities,

the agency is not required to prepare an

IRFA. The Administrator is today

certifying, pursuant to section 605(b) of

the RFA, that this proposed rule will not

have a significant impact on a

substantial number of small entities.

Therefore, the Agency did not prepare

an initial regulatory flexibility analysis.

The RFA requires analysis of the

impacts of a rule on the small entities

subject to the rules’ requirements. See

United States Distribution Companies v.

FERC, 88 F.3d 1105, 1170 (D.C. Cir.

1996). Today’s rule establishes no

requirements applicable to small

entities, and so is not susceptible to

regulatory flexibility analysis as

prescribed by the RFA. (‘‘[N]o

[regulatory flexibility] analysis is

necessary when an agency determines

that the rule will not have a significant

economic impact on a substantial
42192 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

number of small entities that are subject

to the requirements of the rule,’’ United

Distribution at 1170, quoting Mid-Tex

Elec. Co-op v. FERC, 773 F.2d 327, 342

(D.C. Cir. 1985) (emphasis added by

United Distribution court).) The Agency

is thus certifying that today’s rule will

not have a significant economic impact

on a substantial number of small

entities, within the meaning of the RFA.

Under the CWA water quality

standards program, states must adopt

water quality standards for their waters

that must be submitted to EPA for

approval; if the Agency disapproves a

state standard and the state does not

adopt appropriate revisions to address

EPA’s disapproval, EPA must

promulgate standards consistent with

the statutory requirements. EPA has

authority to promulgate criteria or

standards in any case where the

Administrator determines that a revised

or new standard is necessary to meet the

requirements of the Act. These state

standards (or EPA-promulgated

standards) are implemented through

various water quality control programs

including the National Pollutant

Discharge Elimination System (NPDES)

program that limits discharges to

navigable waters except in compliance

with an EPA permit or permit issued

under an approved state program. The

CWA requires that all NPDES permits

must include any limits on discharges

that are necessary to meet state water

quality standards.

Thus, under the CWA, EPA’s

promulgation of water quality criteria or

standards establishes standards that the

state implements through the NPDES

permit process. The state has discretion

in deciding how to meet the water

quality standards and in developing

discharge limits as needed to meet the

standards. While the state’s

implementation of federallypromulgated water quality criteria or

standards may result in new or revised

discharge limits being placed on small

entities, the criteria or standards

themselves do not apply to any

discharger, including small entities.

Today’s rule, as explained above, does

not itself establish any requirements

that are applicable to small entities. As

a result of EPA’s action here, the State

of California will need to ensure that

permits it issues comply with the water

quality standards established by the

criteria in today’s proposed rule. In so

doing, the State will have a number of

discretionary choices associated with

permit writing. While California’s

implementation of today’s rule may

ultimately result in some new or revised

permit conditions for some dischargers,

including small entities, EPA’s action

today does not impose any of these as

yet unknown requirements on small

entities.

Although the statute does not require

EPA to prepare an IRFA when it

proposes water quality criteria which

will establish water quality standards

for California, EPA has undertaken an

analysis equivalent to an IRFA. This

analysis focuses on State and local

implementation procedures related to

the NPDES permit program. This

analysis is included in a document

entitled, Implementation Analysis of

Ambient Water Quality Criteria for

Priority Toxic Pollutants in California

which is part of the administrative

record for this rulemaking. This

document looks at the many

implementation procedures of the

NPDES permit program that the State

implements to control pollutants from

point source discharges. The procedures

discussed in the document include:

methods to calculate water qualitybased effluent limits; mixing zones; sitespecific translators for metals criteria;

compliance schedules; effluent trading;

water-effect ratios; variances; designated

use reclassification; and site-specific

criteria. Each of these implementation

procedures can have an effect on how

water quality standards, based on the

criteria in today’s proposed rule, will

impact NPDES permit holders. Many of

these procedures will lessen impacts on

regulated entities.

The document also looks at

implementation procedures used in the

pretreatment program to control

pollutant discharges from indirect

dischargers. Indirect dischargers include

retail, commercial, and small industrial

facilities that discharge to publicly

owned treatment works (POTWs). Local

entities have significant flexibility to

implement their pretreatment programs.

These procedures include: methods to

calculate local limits (allocation of

pollutants); methods of pollution

prevention for various specific sources;

pretreatment pollutant trading; methods

of low cost pollutant reductions;

technical assistance to move toward or

achieve zero-discharge; cost accounting

to drive down levels of discharges; and

a few of the regulatory relief options

discussed in the direct discharger

section, e.g., compliance schedules.

The discussion illustrates the

significant amount of flexibility

available to the State and local agencies

when implementing the NPDES permit

program and pretreatment program and

emphasizes that appropriate use of the

available implementation tools can

greatly affect the impact to many direct

and indirect dischargers.

K. The Paperwork Reduction Act

This action requires no new or

additional information collection

subject to the Paperwork Reduction Act,

44 U.S.C. 3501 et seq., and therefore no

information collection request will be

submitted to the Office of Management

and Budget for review.

L. The Endangered Species Act

Pursuant to section 7(a) of the

Endangered Species Act (ESA), EPA is

consulting with the U.S. Fish and

Wildlife Service (FWS) and the U.S.

National Marine Fisheries Service

(NMFS) concerning EPA’s rulemaking

action for the State of California. EPA

has initiated informal consultation, and

will complete informal and formal, if

necessary, consultation before final

action on the final rule. As a result of

this consultation, EPA may modify

some provisions of this proposed rule.

As part of the ESA process, EPA will

submit to FWS and NMFS a Biological

Evaluation for their review. When

submitted, this document will become

part of the administrative record for this

rulemaking. If EPA initiates formal

consultation, the FWS and NMFS would

issue a Biological Opinion which may

include Reasonable and Prudent

Alternatives (RPAs). EPA will then

make decisions regarding

implementation of any RPAs. EPA, FWS

and NMFS will continue to work closely

together on this ESA consultation

process.

List of Subjects In 40 CFR Part 131

Environmental protection, Indianlands, Water pollution control, Water

quality standard, Toxic pollutant.

Dated: July 25, 1997.

Carol Browner,

Administrator.

For the reasons set out in the

preamble, part 131 of title 40 of the

Code of Federal Regulations is proposed

to be amended as follows:

PART 131—WATER QUALITY

STANDARDS

1. The authority citation for part 131

continues to read as follows:

Authority: 33 U.S.C. 1251 et seq.

Subpart D—[Amended]

2. Section 131.38 is added to subpart

D to read as follows:

§ 131.38 Establishment of Numeric Criteria

for Priority Toxic Pollutants for the State of

California.

(a) Scope. This section is a general

promulgation of criteria for priority

toxic pollutants in the State of
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42193

California for inland surface waters and

enclosed bays and estuaries. This

section also contains a compliance

schedule provision.

(b)(1) Criteria for Priority Toxic

Pollutants in the State of California.

BILLING CODE 6560–50–P
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BILLING CODE 6560–50–C

Footnotes:

a. These criteria have been revised to

reflect the Agency q1* or RfD, as contained

in the Integrated Risk Information System

(IRIS) as of October 1, 1996. The fish tissue

bioconcentration factor (BCF) from the 1980

documents was retained in each case.

b. This letter is not used as a footnote.

c. These criteria are based on

carcinogenicity of 10 (¥6) risk.

d. The Criteria Maximum Concentration

(CMC) equals the highest concentration of a

pollutant to which aquatic life can be
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42205

exposed for a short period of time without

deleterious effects. Criteria Continuous

Concentration (CCC) equals the highest

concentration of a pollutant to which aquatic

life can be exposed for an extended period

of time (4 days) without deleterious effects.

ug/l equals micrograms per liter.

e. These freshwater aquatic life criteria for

metals are expressed as a function of total

hardness (mg/l) in the water body. The

equations are provided in matrix at

paragraph (b)(2) of this section. Values

displayed above in the matrix correspond to

a total hardness of 100 mg/l.

f. These freshwater aquatic life criteria for

pentachlorophenol are expressed as a

function of pH, and are calculated as follows:

Values displayed above in the matrix

correspond to a pH of 7.8.

CMC=exp(1.005(pH)—4.830).

CCC=exp(1.005(pH)—5.290).

g. These aquatic life criteria for these

compounds were issued in 1980 utilizing the

1980 Guidelines for criteria development.

The acute values shown are final acute

values (FAV) which by the 1980 Guidelines

are instantaneous values as contrasted with

a CMC which is a short-term average.

h. These totals simply sum the criteria in

each column. For aquatic life, there are 30

priority toxic pollutants with some type of

freshwater or saltwater, acute or chronic

criteria. For human health, there are 100

priority toxic pollutants with either ‘‘water +

organism’’ or ‘‘organism only’’ criteria. Note

that these totals count chromium as one

pollutant even though EPA has developed

criteria based on two valence states. In the

matrix, EPA has assigned numbers 5a and 5b

to the criteria for chromium to reflect the fact

that this list of 126 priority pollutants

includes only a single listing for chromium.

i. Criteria for these metals are expressed as

a function of the water-effect ratio, WER, as

defined in paragraph (c) of this section.

CMC=column B1 or C1 value×WER;

CCC=column B2 or C2 value×WER.

j. No criteria for protection of human

health from consumption of aquatic

organisms (excluding water) was presented

in the 1980 criteria document or in the 1986

Quality Criteria for Water. Nevertheless,

sufficient information was presented in the

1980 document to allow a calculation of a

criterion, even though the results of such a

calculation were not shown in the document.

k. This criterion for asbestos is the MCL (40

CFR 131.36).

l. This letter is not used as a footnote.

m. These freshwater and saltwater criteria

for metals are expressed in terms of the

dissolved fraction of the metal in the water

column. Criterion values were calculated by

using EPA’s Clean Water Act 304(a) guidance

values (described in the total recoverable

fraction) and then applying the conversion

factors.

n. EPA is not promulgating human health

criteria for these contaminants. However,

permit authorities should address these

contaminants in NPDES permit actions using

the State’s existing narrative criteria for

toxics.

o. These criteria were promulgated for

specific waters in California in the National

Toxics Rule (‘‘NTR’’), codified at 40 CFR

131.36, December 22, 1992, as amended by

May 4, 1995. The specific waters to which

the NTR criteria apply include: Waters of the

State defined as bays or estuaries and waters

of the State defined as inland, i.e., all surface

waters of the State not ocean waters. These

waters specifically include the San Francisco

Bay upstream to and including Suisun Bay

and the Sacramento-San Joaquin Delta.

Note: This section does not supersede

§ 131.36 (the NTR, as amended), for this

criterion.

p. The CMC = 1/[(f1/CMC1) + (f2/CMC2)]

where f1 and f2 are the fractions of total

selenium that are treated as selenite and

selenate respectively, and f1 + f2 = 1. CMC1

and CMC2 are the CMCs for selenite and

selenate, respectively, or 185.9 ug/l and 12.83

ug/l, respectively. This criterion is in the

total recoverable form. A criterion of 20

ug/l was promulgated for specific waters in

California in the NTR, as amended, and was

promulgated in the total recoverable form.

The specific waters to which the NTR

criterion applies include: Waters of the San

Francisco Bay upstream to and including

Suisun Bay and the Sacramento-San Joaquin

Delta; and waters of Salt Slough, Mud Slough

(north) and the San Joaquin River, Sack Dam

to the mouth of the Merced River.

Note: This rule does not supersede § 131.36

(the NTR, as amended), for this criterion. The

criterion in this section applies to additional

waters of the United States in the State of

California by this rulemaking.

Note also: The State of California adopted

and EPA approved a site specific criterion for

the San Joaquin River, mouth of Merced to

Vernalis; therefore, this criterion does not

apply to these waters.

q. This criterion is in the total recoverable

form. This criterion was promulgated for

specific waters in California in the NTR, as

amended, and was promulgated in the total

recoverable form. The specific waters to

which the NTR criterion applies include:

Waters of the San Francisco Bay upstream to

and including Suisun Bay and the

Sacramento-San Joaquin Delta; and waters of

Salt Slough, Mud Slough (north) and the San

Joaquin River, Sack Dam to Vernalis.

Note: This section does not supersede

§ 131.36 (the NTR, as amended), for this

criterion. This criterion applies to additional

waters of the United States in the State of

California by this rulemaking.

Note also: The State of California adopted

and EPA approved a site-specific criterion for

the Grassland Water District, San Luis

National Wildlife Refuge, and the Los Banos

State Wildlife Refuge; therefore, this criterion

does not apply to these waters.

r. These criteria were promulgated for

specific waters in California in the NTR, as

amended. The specific waters to which the

NTR criteria apply include: Waters of the

State defined as bays or estuaries including

the San Francisco Bay upstream to and

including Suisun Bay and the SacramentoSan Joaquin Delta.

Note: This section does not supersede

§ 131.36 (the NTR, as amended), for these

criteria.

s. These criteria were promulgated for

specific waters in California in the NTR, as

amended. The specific waters to which the

NTR criteria apply include: Waters of the

Sacramento-San Joaquin Delta and waters of

the State defined as inland (i.e., all surface

waters of the State not bays or estuaries or

ocean) that include a MUN use designation.

Note: This section does not supersede

§ 131.36 (the NTR, as amended), for these

criteria.

t. These criteria were promulgated for

specific waters in California in the NTR, as

amended. The specific waters to which the

NTR criteria apply include: Waters of the

State defined as bays and estuaries including

San Francisco Bay upstream to and including

Suisun Bay and the Sacramento-San Joaquin

Delta; and waters of the State defined as

inland (i.e., all surface waters of the State not

bays or estuaries or ocean) without a MUN

use designation.

Note: This section does not supersede

§ 131.36 (the NTR, as amended), for these

criteria.

u. PCBs are a class of chemicals which

include aroclors 1242, 1254, 1221, 1232,

1248, 1260, and 1016, CAS numbers

53469219, 11097691, 11104282, 11141165,

12672296, 11096825, and 12674112,

respectively. The aquatic life criteria apply to

this set of PCBs.

v. This criterion applies to total PCBs or

congener or isomer analyses.

w. This criterion has been recalculated

pursuant to the 1995 Updates: Water Quality

Criteria Documents for the Protection of

Aquatic Life in Ambient Water, Office of

Water, EPA–820–B–96–001, September 1996.

See also Great Lakes Water Quality Initiative

Criteria Documents for the Protection of

Aquatic Life in Ambient Water, Office of

Water, EPA–80–B–95–004, March 1995,

available from the Water Resource Center,

USEPA, 401 M St. SW., mail code RC 4100,

Washington, DC 20460.

x. The State of California has adopted and

EPA has approved site specific criteria for the

Sacramento River (and tributaries) above

Hamilton City; therefore, these proposed

criteria do not apply to these waters.

General Notes

1. This chart lists all of EPA’s priority toxic

pollutants whether or not criteria guidance

are available. Blank spaces indicate the

absence of criteria guidance. Because of

variations in chemical nomenclature systems,

this listing of toxic pollutants does not

duplicate the listing in Appendix A of 40

CFR Part 423. EPA has added the Chemical

Abstracts Service (CAS) registry numbers,

which provide a unique identification for

each chemical.

2. The following chemicals have

organoleptic-based criteria recommendations

that are not included on this chart (for

reasons which are discussed in the

preamble): zinc, 3-methyl-4-chlorophenol.

3. For purposes of this section, freshwater

criteria and saltwater criteria apply as

specified in paragraph (c)(3) of this section.

(2) Factors for Calculating Metals

Criteria:

CMC = WER × (Acute Conversion

Factor) ×

(exp{mA[ln(hardness)]+bA})
42206 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

CCC = WER × (Chronic Conversion

Factor) ×

(exp{mC[ln(hardness)]+bC})

Final CMC and CCC values should be

rounded to two significant figures.

TABLE 1 TO PARAGRAPH (b)(2)

Metal

Conversion

factor (CF) for

freshwater

acute criteria

CF for

freshwater

chronic

criteria

CF for

saltwater

acute

criteria

CF (a) for

saltwater

chronic

criteria

Antimony ............................................................................................... (d) (d) (d) (d)

Arsenic .................................................................................................. 1.000 1.000 1.000 1.000

Beryllium ............................................................................................... (d) (d) (d) (d)

Cadmium (b) ......................................................................................... 0.944 0.909 0.994 0.994

Chromium (III) ....................................................................................... 0.316 0.860 (d) (d)

Chromium (VI) ...................................................................................... 0.982 0.962 0.993 0.993

Copper .................................................................................................. 0.960 0.960 0.83 0.83

Lead (b) ................................................................................................ 0.791 0.791 0.951 0.951

Mercury ................................................................................................. 0.85 0.85 0.85 0.85

Nickel .................................................................................................... 0.998 0.997 0.990 0.990

Selenium ............................................................................................... (c) (c) 0.998 0.998

Silver ..................................................................................................... 0.85 (d) 0.85 (d)

Thallium ................................................................................................ (d) (d) (d) (d)

Zinc ....................................................................................................... 0.978 0.986 0.946 0.946

Footnotes:

(a) Conversion Factors for chronic marine

criteria are not currently available.

Conversion Factors for acute marine criteria

have been used for both acute and chronic

marine criteria.

(b) Conversion Factors for these pollutants

are hardness dependent. CFs are based on a

hardness of 100 mg/l as calcium carbonate

(CaCO3). Other hardness can be used; CFs

should be recalculated using the following

equations:

Cadmium: Acute: CF = 1.136672—[(ln

{hardness})(0.041838)]

Chronic: CF = 1.101672—[(ln

{hardness})(0.041838)]

Lead: Acute and Chronic: CF = 1.46203—[(ln

{hardness})(0.145712)]

(c) Bioaccumulative compound and

inappropriate to adjust to percent dissolved.

(d) EPA has not published an aquatic life

criterion value.

Note: The term ‘‘Conversion Factor’’

represents the recommended conversion

factor for converting a metal criterion

expressed as the total recoverable fraction in

the water column to a criterion expressed as

the dissolved fraction in the water column.

See ‘‘Office of Water Policy and Technical

Guidance on Interpretation and

Implementation of Aquatic Life Metals

Criteria’’, October 1, 1993, by Martha G.

Prothro, Acting Assistant Administrator for

Water, available from the Water Resource

Center, USEPA, 401 M St. SW., mail code RC

4100, Washington, DC 20460; and

§ 131.36(b)(1).

TABLE 2 TO PARAGRAPH (b)(2)

Metal mA bA mC bC

Cadmium .................................................................................................................. 1.128 ¥3.6867 0.7852 ¥2.715

Copper ...................................................................................................................... 0.9422 ¥1.700 0.8545 ¥1.702

Chromium (III) ........................................................................................................... 0.8190 3.688 0.8190 1.561

Lead .......................................................................................................................... 1.273 ¥1.460 1.273 ¥4.705

Nickel ........................................................................................................................ 0.8460 2.255 0.8460 0.0584

Silver ......................................................................................................................... 1.72 ¥6.52 ...................... ......................

Zinc ........................................................................................................................... 0.8473 0.884 0.8473 0.884

Note: The term ‘‘exp’’ represents the base

e exponential function.

(c) Applicability. (1) The criteria in

paragraph (b) of this section apply to the

State’s designated uses cited in

paragraph (d) of this section and apply

concurrently with any criteria adopted

by the State, except when State

regulations contain criteria which are

more stringent for a particular parameter

and use, or except as provided in

footnotes p, q, and x in paragraph (b) of

this section.

(2) The criteria established in this

section are subject to the State’s general

rules of applicability in the same way

and to the same extent as are other

Federally-adopted and State-adopted

numeric toxics criteria when applied to

the same use classifications including

mixing zones, and low flow values

below which numeric standards can be

exceeded in flowing fresh waters.

(i) For all waters with mixing zone

regulations or implementation

procedures, the criteria apply at the

appropriate locations within or at the

boundary of the mixing zones;

otherwise the criteria apply throughout

the water body including at the point of

discharge into the water body.

(ii) The State shall not use a low flow

value below which numeric standards

can be exceeded that is less stringent

than the following for water suitable for

the establishment of low flow return

frequencies (i.e., streams and rivers):

Aquatic Life

Acute Criteria (CMC): 1 Q 10 or 1 B 3

Chronic Criteria (CCC): 7 Q 10 or 4 B 3

Human Health

Non-carcinogens: 30 Q 5

Carcinogens: Harmonic Mean

Flow

Where:

CMC (Criteria Maximum Concentration) is

the water quality criteria to protect against

acute effects in aquatic life and is the highest

instream concentration of a priority toxic

pollutant consisting of a short-term average
Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules 42207

not to be exceeded more than once every

three years on the average;

CCC (Continuous Criteria Concentration) is

the water quality criteria to protect against

chronic effects in aquatic life and is the

highest in stream concentration of a priority

toxic pollutant consisting of a 4-day average

not to be exceeded more than once every

three years on the average;

1 Q 10 is the lowest one day flow with an

average recurrence frequency of once in 10

years determined hydrologically;

1 B 3 is biologically based and indicates an

allowable exceedence of once every 3 years.

It is determined by EPA’s computerized

method (DFLOW model);

7 Q 10 is the lowest average 7 consecutive

day low flow with an average recurrence

frequency of once in 10 years determined

hydrologically;

4 B 3 is biologically based and indicates an

allowable exceedence for 4 consecutive days

once every 3 years. It is determined by EPA’s

computerized method (DFLOW model);

30 Q 5 is the lowest average 30 consecutive

day flow with an average recurrence

frequency of once in 5 years determined

hydrologically; and the harmonic mean flow

is a long term mean flow value calculated by

dividing the number of daily flows analyzed

by the sum of the reciprocals of those daily

flows.

(iii) If the State does not have such a

low flow value below which numeric

standards do not apply, then the criteria

included in paragraph (d) or this section

herein apply at all flows.

(3) The aquatic life criteria in the

matrix in paragraph (b) of this section

apply as follows:

(i) For waters in which the salinity is

equal to or less than 1 part per thousand

95% or more of the time, the applicable

criteria are the freshwater criteria in

Column B;

(ii) For waters in which the salinity is

equal to or greater than 10 parts per

thousand 95% or more of the time, the

applicable criteria are the saltwater

criteria in Column C except for

selenium in the San Francisco Bay

estuary where the applicable criteria are

the freshwater criteria in Column B

(refer to footnotes p and q in section

(b)(1) of this section); and

(iii) For waters in which the salinity

is between 1 and 10 parts per thousand

as defined in paragraphs (c)(3)(i) and (ii)

of this section, the applicable criteria

are the more stringent of the freshwater

or saltwater criteria. However, the

Regional Administrator may approve

the use of the alternative freshwater or

saltwater criteria if scientifically

defensible information and data

demonstrate that on a site-specific basis

the biology of the water body is

dominated by freshwater aquatic life

and that freshwater criteria are more

appropriate; or conversely, the biology

of the water body is dominated by

saltwater aquatic life and that saltwater

criteria are more appropriate.

(4) Application of metals criteria. (i)

For purposes of calculating freshwater

aquatic life criteria for metals from the

equations in paragraph (b)(2) of this

section, for waters with a hardness of

400 mg/l or less as calcium carbonate,

the actual ambient hardness of the

surface water shall be used in those

equations. For waters with a hardness of

over 400 mg/l as calcium carbonate, a

hardness of 400 mg/l as calcium

carbonate shall be used with a default

Water-Effect Ratio (WER) of 1, or the

actual hardness of the ambient surface

water shall be used with a WER. The

same provisions apply for calculating

the metals criteria for the comparisons

provided for in paragraph (c)(3)(iii) of

this section.

(ii) The hardness values used shall be

consistent with the design discharge

conditions established in paragraph

(c)(2) of this section for flows and

mixing zones.

(iii) The criteria for metals

(compounds #1–#13 in paragraph (b) of

this section) are expressed as dissolved

except where otherwise noted. For

purposes of calculating aquatic life

criteria for metals from the equations in

footnote i in the criteria matrix in

paragraph (b)(1) of this section and the

equations in paragraph (b)(2) of this

section, the water effect ratio is

generally computed as a specific

pollutant’s acute or chronic toxicity

value measured in water from the site

covered by the standard, divided by the

respective acute or chronic toxicity

value in laboratory dilution water. To

use a water effect ratio other than the

default of 1, the WER must be

determined as set forth in Interim

Guidance on Determination and Use of

Water Effect Ratios, U.S. EPA Office of

Water, EPA–823–B–94–001, February

1994, or alternatively, other

scientifically defensible methods

adopted by the State as part of its water

quality standards program and approved

by EPA. For calculation of criteria using

site-specific values for both the

hardness and the water effect ratio, the

hardness used in the equations in

paragraph (b)(2) of this section must be

determined as required in paragraph

(c)(4)(ii) of this section. Water hardness

must be calculated from the measured

calcium and magnesium ions present,

and the ratio of calcium to magnesium

should be approximately the same in

standard laboratory toxicity testing

water as in the site water.

(d)(1) Except as specified in paragraph

(d)(3) of this section, all waters assigned

any aquatic life or human health use

classifications in the Water Quality

Control Plans for the various Basins of

the State (‘‘Basin Plans’’), as amended,

adopted by the California State Water

Resources Control Board (‘‘SWRCB’’),

except for ocean waters covered by the

Water Quality Control Plan for Ocean

Waters of California (‘‘Ocean Plan’’)

adopted by the SWRCB with resolution

Number 90–27 on March 22, 1990, are

subject to the criteria in paragraph (d)(2)

of this section, without exception. These

criteria apply to waters contained in the

Basin Plans. More particularly, these

criteria apply to waters in the Basin

Plan chapters specifying water quality

objectives (the State equivalent of

federal water quality criteria) for the

toxic pollutants identified in paragraph

(d)(2) of this section. Although the State

has adopted several use designations for

each of these waters, for purposes of this

action, the specific standards to be

applied in paragraph (d)(2) of this

section are based on the presence in all

waters of some aquatic life designation

and the presence or absence of the MUN

use designation (municipal and

domestic supply). (See Basin Plans for

more detailed use definitions.)

(2) The following criteria from the

matrix in paragraph (b)(1) of this section

apply to the water and use

classifications defined in paragraph

(d)(1) of the section and identified

below:

Water and use classification Applicable Criteria

All inland waters of the United States or enclosed bays and estuaries

that are waters of the United States that include a MUN use designation.

These waters are assigned the criteria in:

Columns B1 and B2—all pollutants

Columns C1 and C2—all pollutants

Column D1—all pollutants

All inland waters of the United States or enclosed bays and estuaries

that are waters of the United States that do not include a MUN use

designation.

These waters are assigned the criteria in:

Columns B1 and B2—all pollutants

Columns C1 and C2—all pollutants

Column D2—all pollutants
42208 Federal Register / Vol. 62, No. 150 / Tuesday, August 5, 1997 / Proposed Rules

(3) Nothing in this section is intended

to supersede specific criteria, including

specific criteria for the San Francisco

Bay estuary, promulgated for California

in § 131.36.

(4) The human health criteria shall be

applied at the State-adopted 10 (¥6)

risk level.

(5) Nothing in this section applies to

waters located in Indian Country.

(e) Schedules of Compliance: (1) It is

presumed that new and existing point

source dischargers will promptly

comply with any new or more

restrictive water quality-based effluent

limitations (‘‘WQBELs’’) based on the

water quality criteria set forth in this

section.

(2) When a permit issued on or after

the effective date of this regulation to a

new discharger contains a WQBEL

based on water quality criteria set forth

in the section, the permittee shall

comply with such WQBEL upon the

commencement of the discharge. A new

discharger is defined as any building,

structure, facility, or installation from

which there is or may be a ‘‘discharge

of pollutants’’ (as defined in 40 CFR

122.2) to the State of California’s inland

surface waters or enclosed bays and

estuaries, the construction of which

commenced after the effective date of

this regulation.

(3) Where an existing discharger

reasonably believes that it will be

infeasible to promptly comply with a

new or more restrictive WQBEL based

on the water quality criteria set forth in

this section, the discharger may request

approval from the permit issuing

authority for a schedule of compliance.

(4) A compliance schedule shall

require compliance with WQBELs based

on water quality criteria set forth in this

section as soon as possible, taking into

account the dischargers technical ability

to achieve compliance with such

WQBEL.

(5) If the schedule of compliance

exceeds one year from the date of permit

issuance, reissuance or modification,

the schedule shall set forth interim

requirements and dates for their

achievement. The dates of completion

between each requirement may not

exceed one year. If the time necessary

for completion of any requirement is

more than one year and is not readily

divisible into stages for completion, the

permit shall require, at a minimum,

specified dates for annual submission of

progress reports on the status of interim

requirements.

(6) In no event shall the permit

issuing authority approve a schedule of

compliance for a point source discharge

which exceeds five years from the date

of permit issuance, reissuance, or

modification, whichever is sooner.

Where shorter schedules of compliance

are prescribed or schedules of

compliance are prohibited by law, those

provisions shall govern.

(7) If a schedule of compliance

exceeds the term of a permit, interim

permit limits effective during the permit

shall be included in the permit and

addressed in the permit’s fact sheet or

statement of basis. The administrative

record for the permit shall reflect final

permit limits and final compliance

dates. Final compliance dates for final

permit limits, which do not occur

during the term of the permit, must

occur within five years from the date of

issuance, reissuance or modification of

the permit which initiates the

compliance schedule. Where shorter

schedules of compliance are prescribed

or schedules of compliance are

prohibited by law, those provisions

shall govern.

(8) No compliance schedule

established in accordance with

paragraphs (e)(3) through (7) of this

section shall allow more than ten years

from the effective date of this rule to

achieve compliance with any WQBEL

based on the criteria set forth in this

section.

[FR Doc. 97–20173 Filed 8–4–97; 8:45 am]

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