31682 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 131

[FRL–6587–9]

RIN 2040–AC44

Water Quality Standards;

Establishment of Numeric Criteria for

Priority Toxic Pollutants for the State

of California

AGENCY: Environmental Protection

Agency.

ACTION: Final rule.

SUMMARY: This final rule promulgates:

numeric aquatic life criteria for 23

priority toxic pollutants; numeric

human health criteria for 57 priority

toxic pollutants; and a compliance

schedule provision which authorizes

the State to issue schedules of

compliance for new or revised National

Pollutant Discharge Elimination System

permit limits based on the federal

criteria when certain conditions are met.

EPA is promulgating this rule based

on the Administrator’s determination

that numeric criteria are necessary in

the State of California to protect human

health and the environment. The Clean

Water Act requires States to adopt

numeric water quality criteria for

priority toxic pollutants for which EPA

has issued criteria guidance, the

presence or discharge of which could

reasonably be expected to interfere with

maintaining designated uses.

EPA is promulgating 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. Thus, the

State of California has been without

numeric water quality criteria for many

priority toxic pollutants as required by

the Clean Water Act, necessitating this

action by EPA. These Federal criteria

are legally applicable in the State of

California for inland surface waters,

enclosed bays and estuaries for all

purposes and programs under the Clean

Water Act.

EFFECTIVE DATE: This rule shall be

effective May 18, 2000.

ADDRESSES: The administrative record

for today’s final rule is available for

public inspection at the U.S.

Environmental Protection Agency,

Region 9, Water Division, 75 Hawthorne

Street, San Francisco, California 94105,

between the hours of 8:00 a.m. and 4:30

p.m. For access to the administrative

record, call Diane E. Fleck, P.E., Esq. at

415 744–1984 for an appointment. A

reasonable fee will be charged for

photocopies.

FOR FURTHER INFORMATION CONTACT:

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

Woods, U.S. Environmental Protection

Agency, Region 9, Water Division, 75

Hawthorne Street, San Francisco,

California 94105, 415–744–1984 or 415–

744–1997, respectively.

SUPPLEMENTARY INFORMATION: This

preamble is organized according to the

following outline:

A. Potentially Affected Entities

B. Introduction and Overview

1. Introduction

2. Overview

C. Statutory and Regulatory Background

D. California Water Quality Standards

Actions

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 Criteria for

Priority Toxic Pollutants

a. State-Adopted Site-Specific Criteria Under

EPA Review

b. State-Adopted Site-Specific Criteria With

EPA Approval

E. Rationale and Approach For Developing

the Final Rule

1. Legal Basis

2. Approach for Developing this Rule

F. Derivation of Criteria

1. Section 304(a) Criteria Guidance Process

2. Aquatic Life Criteria

a. Freshwater Acute Selenium Criterion

b. Dissolved Metals Criteria

c. Application of Metals Criteria

d. Saltwater Copper Criteria

e. Chronic Averaging Period

f. 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. Excluded Section 304(a) Human Health

Criteria

f. Cancer Risk Level

G. Description of Final Rule

1. Scope

2. EPA Criteria for Priority Toxic Pollutants

3. Implementation

4. Wet Weather Flows

5. Schedules of Compliance

6. Changes from Proposed Rule

H. Economic Analysis

1. Costs

2. Benefits

I. Executive Order 12866, Regulatory

Planning and Review

J. Unfunded Mandates Reform Act of 1995

K. Regulatory Flexibility Act

L. Paperwork Reduction Act

M. Endangered Species Act

N. Congressional Review Act

O. Executive Order 13084, Consultation and

Coordination With Indian Tribal

Governments

P. National Technology Transfer and

Advancement Act

Q. Executive Order 13132 on Federalism

R. Executive Order 13045 on Protection of

Children From Environmental Health

Risks and Safety Risks

A. 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 affected by this

rulemaking since water quality criteria

are used by the State in developing

National Pollutant Discharge

Elimination System (NPDES) permit

limits. Categories and entities that

ultimately may be affected include:

Category Examples of potentially affected entities

Industry ............................................................... Industries discharging pollutants to surface waters in California or to publicly-owned treatment

works.

Municipalities ...................................................... Publicly-owned treatment works discharging pollutants to surface waters in California

This table is not intended to be

exhaustive, but rather provides a guide

for readers regarding entities likely to be

affected by this action. This table lists

the types of entities that EPA is now

aware could potentially be affected by

this action. Other types of entities not

listed in the table could also be affected.

To determine whether your facility

might be affected by this action, you

should carefully examine the

applicability criteria in § 131.38(c). If

you have questions regarding the

applicability of this action to a

particular entity, consult the persons

listed in the preceding FOR FURTHER

INFORMATION CONTACT section.

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31683

B. Introduction and Overview

1. Introduction

This section introduces the topics

which are addressed in the preamble

and provides a brief overview of EPA’s

basis and rationale for promulgating

Federal criteria for the State of

California. Section C 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 D 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 E provides the rationale and

approach for developing this final rule,

including a discussion of EPA’s legal

basis for this final rule. Section F

describes the development of the

criteria included in this rule. Section G

summarizes the provisions of the final

rule and discusses implementation

issues. Sections H, I, J, K , L, M, N, O,

P, and Q briefly address the

requirements of Executive Order 12866,

the Unfunded Mandates Reform Act of

1995, the Regulatory Flexibility Act, the

Paperwork Reduction Act, the

Endangered Species Act, the

Congressional Review Act, Executive

Order 13084, Consultation and

Coordination with Indian Tribal

Governments, the National Technology

Transfer and Advancement Act, and

Executive Order 13132, Federalism,

respectively.

The proposal for this rulemaking was

published in the Federal Register on

August 5, 1997. Changes from the

proposal are generally addressed in the

body of this preamble and specifically

addressed in the response to comments

document included in the

administrative record for this

rulemaking. EPA responded to all

comments on the proposed rule,

including comments received after the

September 26, 1997, deadline. Although

EPA is under no legal obligation to

respond to late comments, EPA made a

policy decision to respond to all

comments.

Since detailed information concerning

many of the topics in this preamble was

published previously in the Federal

Register in preambles for this and other

rulemakings, references are frequently

made to those preambles. Those

rulemakings include: Water Quality

Standards; Establishment of Numeric

Criteria for Priority Toxic Pollutants for

the State of California; Proposed Rule,

62 FR 42159, August 5, 1997 (referred

to as the ‘‘proposed CTR’’); 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

proposed CTR and its preamble, and the

NTR, as amended, and its preambles are

contained in the administrative record

for this rulemaking.

EPA is making this final rule effective

upon publication. Under the

Administrative Procedure Act, 5 U.S.C.

553(d)(3), agencies must generally

publish a rule no more than 30 days

prior to the effective date of the rule

except as otherwise provided for by the

Agency for good cause. The purpose of

the 30-day waiting period is to give

affected parties a reasonable time to

adjust their behavior before the final

rule takes effect. See Omnipoint Corp. v.

F.C.C., 78 F.3d 620, 630–631 (D.C. Cir.

1996); Riverbend Farms, Inc. v.

Madigan, 958 F.2d 1479, 1485 (9th Cir.

1992).

In this instance, EPA finds good cause

to make the final rule effective upon

publication. In order to find good cause,

an Agency needs to find that the 30-day

period would be: (1) Impracticable, (2)

unnecessary, or (3) contrary to the

public interest. Here EPA is relying on

the second reason to support its finding

of good cause. EPA also notes that the

State has requested EPA to make the

rule immediately effective.

EPA finds that in this instance,

waiting 30 days to make the rule

effective is unnecessary. As explained

in further detail elsewhere in this

preamble, this rule is not self

implementing; rather it establishes

ambient conditions that the State of

California will implement in future

permit proceedings. These permit

proceedings will, by regulation, take

longer than 30 days to complete. This

means that although the rule is

immediately effective, no discharger’s

conduct would be altered under the rule

in less than 30 days, and therefore the

30-day period is unnecessary.

2. Overview

This final rule establishes ambient

water quality criteria for priority toxic

pollutants in the State of California. The

criteria in this final rule will

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 D), for the State of

California. Since EPA had approved

these criteria, it was not necessary to

include them in the 1992 NTR for these

criteria. However, the EPA-approved

criteria were subsequently invalidated

in State litigation. Thus, this final rule

contains criteria to fill the gap created

by the State litigation.

This final 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

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

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 final 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 determine

whether further action to protect water

quality in Indian Country is necessary.

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 (WQBELs) in

31684 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

National Pollutant Discharge

Elimination System (NPDES) permits

and wasteload allocations for total

maximum daily loads (TMDLs) 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 decided

to exercise her CWA authorities to move

forward the toxic control program,

consistent with the CWA and with the

State of California’s water quality

standards program.

Today’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 numeric water quality criteria

for toxic pollutants. This section was

added to the CWA by Congress in 1987.

Prior to today, the State of California

had been the only State in the Nation for

which CWA section 303(c)(2)(B) had

remained 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. The

Administrator determined that this rule

was 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, and EPA approves,

criteria consistent with statutory

requirements, as envisioned by Congress

in the CWA, EPA intends to stay this

rule. If within the applicable time frame

for judicial review, the States’ standards

are challenged, EPA will withdraw this

rule after such judicial review is

complete and the State standards are

sustained.

C. Statutory and Regulatory

Background

The preamble to the August 5, 1997,

proposed rule provided a general

discussion of EPA’s statutory and

regulatory authority to promulgate water

quality criteria for the State of

California. See 62 FR 42160–42163. EPA

is including that discussion in the

record for the final rule. Commenters

questioned EPA’s authority to

promulgate certain aspects of the

proposal. EPA is responding to those

comments in the appropriate sections of

this preamble, and in the response to

comments document included in the

administrative record for this

rulemaking. Where appropriate, EPA’s

responses expand upon the discussion

of statutory and regulatory authority

found in the proposal.

D. California Water Quality Standards

Actions

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

Resources 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 Waters Plan

(ISWP), the Enclosed Bays and Estuaries

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 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

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31685

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 objective

for the San Francisco Bay and Delta,

because there was clear evidence that

the objective 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 parts per billion (ppb) (four day

average) and 20 ppb (1 hour average),

the freshwater criteria. EPA reaffirmed

its disapproval of Californias’ sitespecific selenium objective 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), certain disapproved

aspects of California’s water quality

standards were 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, 22229, 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 a subsequent section of this

preamble.

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 final rule. However,

for clarity in reading a comprehensive

rule for the State of California, these

criteria are incorporated into 40 CFR

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

40 CFR 131.38(b)(1) and 40 CFR

131.38(d)(3) clarify which criteria (and

for which specific water bodies) were

promulgated by the NTR, as amended,

and are therefore excluded from this

final 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-methyl-4,6-dinitrophenol

2,4-dinitrophenol

benzidine

bis(2-chloroethyl)ether

bis(2-ethylhexyl)phthalate

3,3-dichlorobenzidine

diethyl phthalate

dimethyl phthalate

di-n-butyl phthalate

2,4-dinitrotoluene

1,2-diphenylhydrazine

hexachlorobutadiene

hexachlorocyclopentadiene

hexachloroethane

isophorone

nitrobenzene

n-nitrosodimethylamine

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

31686 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

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 action

criteria for priority toxic pollutants,

which are not covered by the NTR, as

amended, or by the State through EPAapproved site-specific criteria, for

waters of the United States in the State

of California.

4. State-Adopted, Site-Specific Criteria

for Priority Toxic Pollutants

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.

a. State-Adopted Site-Specific Criteria

Under EPA Review

The State of California has recently

reviewed and updated all of its RWQCB

Basin Plans. All of the 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 has not yet concluded

consultation under the Endangered

Species Act with the U.S. Department of

Interior, Fish and Wildlife Service, and

the U.S. Department of Commerce,

National Marine Fisheries Service, on

EPA’s tentative approval/disapproval

actions on the RWQCB Basin Plans. In

this situation, the more stringent of the

two criteria (the State-adopted sitespecific criteria in the RWQCB Basin

Plans, or the Federal criteria in this final

rule), would be used for water quality

programs including the calculation of

water quality-based effluent criteria in

National Pollutant Discharge

Elimination System (NPDES) permits.

b. State-Adopted Site-Specific Criteria

With EPA Approval

In several cases, the EPA Regional

Administrator has already reviewed and

approved State-adopted site-specific

criteria within the State of California.

Several of these cases are discussed in

this section. All of the EPA approval

letters referenced in today’s preamble

are contained in the administrative

record for today’s rule.

Sacramento River: EPA has approved

site-specific acute criteria for copper,

cadmium and zinc in the Sacramento

River, upstream of Hamilton City, in the

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 final 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 final 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 statewide criteria

promulgated in today’s final rule.

San Joaquin River: The selenium

criteria in this rule are not applicable to

portions of the San Joaquin River, in the

Central Valley Region, because selenium

criteria have been either previously

approved by EPA or previously

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 final

rule does not affect this Federallyapproved, State-adopted site-specific

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 this final 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 final 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 final rule, a chronic criterion

for selenium for the Grassland Water

District, San Luis National Wildlife

Refuge and Los Banos State Wildlife

Refuge, and thus, it is not included in

this final rule.

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31687

San Francisco Regional Board Basin

Plan of 1986: EPA approved several

priority toxic pollutant objectives (CWA

criteria) that were contained in the1986

San Francisco Regional Board Basin

Plan, as amended by SWRCB Resolution

Numbers 87–49, 87–82 and 87–92, by

letters dated September 2, 1987 and

December 24, 1987. This Basin Plan, the

SWRCB Resolutions, and the EPA

approval letters are contained in the

administrative record for this

rulemaking. It is not necessary to

include these criteria for priority toxic

pollutants that are contained in the San

Francisco Regional Board’s 1986 Basin

Plan as amended, and approved by EPA.

Priority pollutants in this situation are

footnoted in the matrix at 131.38(b)(1)

with footnote ‘‘b.’’ Where gaps exist in

the State adoption and EPA approval of

priority toxic pollutant objectives, the

criteria in today’s rule apply.

EPA is assigning ‘‘human health,

water and organism consumption’’

criteria to waters with the States’

municipal or ‘‘MUN’’ beneficial use

designation in the Basin Plan. Also,

some pollutants regulated through the

Basin Plan have different averaging

periods, e.g., one hour as compared with

the rule’s ‘‘short-term.’’ However, where

classes of chemicals, such as

polynuclear aromatic hydrocarbons, or

PAHs, and phenols, are regulated

through the Basin Plan, but not specific

chemicals within the category, specific

chemicals within the category are

regulated by today’s rule.

E. Rationale and Approach for

Developing the Final Rule

This section explains EPA’s legal

basis for today’s final rule, and

discusses EPA’s general approach for

developing the specific requirements for

the State of California.

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

today’s final rule.

As discussed 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. 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 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.

EPA does not believe that it is

necessary to support the criteria in

today’s rule on a pollutant-specific,

water body-by-water-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. Moreover, because these

criteria are ambient criteria that define

attainment of the designated uses, their

application to all water bodies will

result in additional controls on

dischargers only where necessary to

protect the designated uses.

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

States to conduct triennial reviews of

their water quality standards and submit

the results of those reviews to EPA 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 section

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

Administrator making a generic finding

of inaction by the State without the

need to develop pollutant specific data

for individual stream segments. Finally,

the reference in section 303(c)(2)(B) to

section 304(a) criteria suggests that

section 304(a) criteria serve as default

criteria; that once EPA has issued them,

States were to adopt numeric criteria for

those pollutants based on the 304(a)

criteria, unless they had other

scientifically defensible criteria. EPA

also notes that this rule follows the

approach EPA took nationally in

promulgating the NTR for States that

failed to comply with CWA section

303(c)(2)(B). 57 FR 60848, December 22,

1992. EPA incorporates the discussion

in the NTR preamble as part of this

rulemaking record.

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 final rule would not impose

any undue or inappropriate burden on

the State of California or its dischargers.

It merely puts in place numeric criteria

31688 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

for toxic pollutants that are already used

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 and subsequently withdraw

them.

2. Approach for Developing This Rule

In summary, EPA developed the

criteria promulgated in today’s final rule

as follows. Where EPA promulgated

criteria for California in the NTR, EPA

has not acted to amend the criteria in

the NTR. Where criteria for California

were not included in the NTR, EPA

used section 304(a) National criteria

guidance documents as a starting point

for the criteria promulgated in this rule.

EPA then determined whether new

information since the development of

the national criteria guidance

documents warranted any changes. New

information came primarily 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 (see also 63 FR

68354). 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 sections. This revised

information was used to develop the

water quality criteria promulgated here

for the State of California.

F. 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 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.)

EPA received many comments related

to the issue of what criteria should

apply in the CTR if the CWA section

304(a) criteria guidance is undergoing

re-evaluation, or if new data are

developed that may affect a

recommended criterion. As science is

always evolving, EPA is faced with the

challenge of promulgating criteria that

reflect the best science and sound

science. EPA addressed this challenge

in some detail in its Federal Register

notice that contained the Agency’s

current section 304(a) criteria guidance

(63 FR 68335, December 10, 1998).

There, EPA articulated its policy,

reiterated here, that the existing criteria

guidance represent the Agency’s best

assessment until such time as EPA’s reevaluation of a criteria guidance value

for a particular chemical is complete.

The reason for this is that both EPA’s

human health criteria guidance and

aquatic life criteria guidance are

developed taking into account

numerous variables. For example, for

human health criteria guidance, EPA

evaluates many diverse toxicity studies,

whose results feed into a reference dose

or cancer potency estimate that, along

with a number of exposure factors and

determination of risk level, results in a

guidance criterion. For aquatic life, EPA

evaluates many diverse aquatic toxicity

studies to determine chronic and acute

toxicity taking into account how other

factors (such as pH, temperature or

hardness) affect toxicity. EPA also, to

the extent possible, addresses

bioaccumulation or bioconcentration.

EPA then uses this toxicity information

along with exposure information to

determine the guidance criterion.

Importantly, EPA subjects such

evaluation to peer review and/or public

comment.

For these reasons, EPA generally does

not make a change to the 304(a) criteria

guidance based on a partial picture of

the evolving science. This makes sense,

because to address one piece of new

data without looking at all relevant data

is less efficient and results in regulatory

impacts that may go back and forth,

when in the end, the criteria guidance

value does not change that much.

Certain new changes, however, do

warrant change in criteria guidance,

such as a change in a value in EPA’s

Integrated Risk Information System

(IRIS) because it represents the Agency

consensus about human health impacts.

These changes are sufficiently examined

across the Agency such that EPA

believes they can be incorporated into

EPA’s water quality criteria guidance.

EPA has followed this approach in the

CTR. Included in the administrative

record for today’s rule is a document

entitled ‘‘Status of Clean Water Act

Section 304(a) Criteria’’ which further

explains EPA’s policy on managing

change to criteria guidance.

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

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31689

the uses of, both fresh and salt 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

in the water and their uses.’’ (45 FR

79341.) EPA’s guidelines are designed to

derive criteria that protect aquatic

communities. 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

averages, rather than one number, in

order that the criterion more accurately

reflect toxicological and practical

realities. The combination of a criterion

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

continuous concentration (CCC), a fourday average concentration limit, are

designed to provide protection of

aquatic life and its uses from acute and

chronic toxicity to animals and plants,

without being as restrictive as a onenumber criterion would have to be

(1985 Guidelines, pages 4 & 5). The

terms CMC and CCC are the formal

names for the two (acute and chronic)

values of a criterion for a pollutant;

however, this document will also use

the informal synonyms acute criterion

and chronic criterion.

The two-number criteria are intended

to identify average pollutant

concentrations which will produce

water quality generally suited to

maintenance of aquatic life and

designated 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 may be insufficient unless the

time period is short, because excursions

higher than the average may kill or

cause substantial damage in short

periods.

A minimum data set of eight specified

families is recommended 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. EPA’s application of its guidelines

to develop the criteria matrix in this

rule is judged by the Agency to be

appropriate for all waters of the United

States (U.S.), and to all ecosystems

(1985 Guidelines, page 4) including

those waters of the U.S. and ecosystems

in the State of California.

Fresh water and salt water (including

both estuarine and marine waters) have

different chemical compositions, and

freshwater and saltwater species often

do not inhabit the same water. To

provide additional accuracy, criteria are

developed for fresh water and for salt

water.

For this rule, 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 ten pollutants: arsenic,

cadmium, chromium (VI), copper,

dieldrin, endrin, lindane (gamma BHC),

nickel, pentachlorophenol, and zinc.

The updates used as the basis for this

rule 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 ten pollutants were derived.

The polychlorinated biphenyls (PCB)

criteria in the criteria matrix for this

rule differs from that in the NTR, as

amended; for this rule, the criteria are

expressed as the sum of seven aroclors,

while for the NTR, as amended, the

criteria are expressed for each of seven

aroclors. The aquatic life criteria for

PCBs in the CTR are based on the

criteria contained in the 1980 criteria

guidance document for PCBs which is

included in the administrative record

for this rule. This criteria document

explains the derivation of aquatic life

criteria based on total PCBs. For more

information see the Response to

Comments document for this rule.

Today’s chronic aquatic life criteria for

PCBs are based on a final residue value

(FRV). In EPA’s guidelines for deriving

aquatic life criteria, an FRV-based

criterion is intended to prevent

concentrations of pollutants in

commercially or recreationally

important aquatic species from affecting

the marketability of those species or

affecting the wildlife that consume

aquatic life.

The proposed CTR included an

updated freshwater and saltwater

aquatic life criteria for mercury. In

today’s final rule, EPA has reserved the

mercury criteria for freshwater and

saltwater aquatic life, but is

promulgating human health criteria for

mercury for all surface waters in

California. In some instances, the

human health mercury criteria included

in today’s final rule may not protect

some aquatic species or threatened or

endangered species. In such instances,

more stringent mercury limits may be

determined and implemented through

use of the State’s narrative criterion. The

reasons for reserving the mercury

aquatic life numbers are explained in

further detail in Section L, Endangered

Species Act.

a. Freshwater Acute Selenium Criterion

EPA proposed a different freshwater

acute aquatic life criterion for selenium

for this rule than was promulgated in

the NTR, as amended. EPA’s proposed

action was consistent with EPA’s

proposed selenium criterion maximum

concentration for the Water Quality

Guidance for the Great Lakes System (61

FR 58444, November 14, 1996). This

proposal took 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 which

indicated that various forms of selenium

are additive. Additivity increases the

toxicity of mixtures of different forms of

the pollutant. The proposed 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.

The preamble to the August 5, 1997,

proposed rule provided a lengthy

discussion of this proposed criterion for

the State of California. See 62 FR

42160–42208. EPA incorporates that

discussion here as part of this

rulemaking record. In 1996, a similar

discussion was included in the

proposed rule for the Great Lakes

System. Commenters questioned several

aspects of the Great Lakes proposal. EPA

is continuing to respond to those

comments, and to follow up with

additional literature review and toxicity

testing. In addition, the U.S. FWS and

U.S. NMFS (collectively, the Services)

are concerned that EPA’s proposed

criterion may not be sufficiently

protective of certain threatened and

endangered species in California.

Because the Services believe there is a

lack of data to show for certain that the

proposed criterion would not affect

threatened and endangered species, the

Services prefer that EPA further

investigate the protectiveness of the

31690 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

criterion before finalizing the proposed

criterion. Therefore, EPA is not

promulgating a final acute freshwater

selenium criterion at this time.

b. 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,

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 aquatic life

metals criteria. The principal issue was

the correlation between metals that are

measured and metals that are

bioavailable and toxic to aquatic life. It

is now the Agency’s policy that the use

of dissolved metal to set and measure

compliance with aquatic life 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.

Since EPA’s previous aquatic life

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.

EPA included a set of recommended

freshwater conversion factors with its

Metals Policy (see Office of Water Policy

and Technical Guidance on

Interpretation and Implementation of

Aquatic Life Metals Criteria, Martha G.

Prothro, Acting Assistant Administrator

for Water, October 1, 1993). 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. They are also

contained in today’s rule at 40 CFR

131.38(b)(2).

The preamble to the August 5, 1997,

proposed rule provided a more detailed

discussion of EPA’s metals policy

concerning the aquatic life water quality

criteria for the State of California. See 62

FR 42160–42208. EPA incorporates that

discussion here as part of this

rulemaking record. Many commenters

strongly supported the Agency’s policy

on dissolved metals aquatic life criteria.

A few commenters expressed an

opinion that the metals policy may not

provide criteria that are adequately

protective of aquatic or other species.

Responses to those comments are

contained in a memo to the CTR record

entitled ‘‘Discussion of the Use of

Dissolved Metals in the CTR’’ (February

1, 2000, Jeanette Wiltse) and EPA’s

response to comments document which

are both contained in the administrative

record for the final rule.

Calculation of Aquatic Life Dissolved

Metals Criteria: Metals criteria values

for aquatic life in today’s 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 metals criteria

value is calculated separately for each

hardness using the table at 40 CFR

131.38(b)(2). (The hardness-dependent

freshwater values presented in the

matrix at 40 CFR 131.38(b)(1) have been

calculated using a hardness of 100 mg/

l as CaCO3 for illustrative purposes

only.) The hardness-dependent criteria

are then multiplied by the appropriate

conversion factors in the table at 40 CFR

131.38(b)(2). Saltwater and freshwater

metals criteria that are not hardnessdependent are calculated by taking the

total recoverable criteria values (from

EPA’s national section 304(a) criteria

guidance, as updated and described in

section F.2.a.) before rounding, and

multiplying them by the appropriate

conversion factors. The final dissolved

metals criteria values, as they appear in

the matrix at 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 these differences result in changes

in the partitioning between dissolved

and absorbed forms of the metal. This

means that if effluent limits were

expressed in the dissolved form,

additional particulate metal could

dissolve in the receiving water causing

the criteria to be exceeded. 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 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 water

quality standards based on 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.

c. 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

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31691

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. A copy of the

Handbook is contained in the

administrative record for today’s rule. 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 as

part of a water quality criteria in

California as opposed to the application

on a discharger-by-discharger basis

through individual NPDES permits.

This approach is technically sound and

an efficient use of resources. However,

discharger specific WERs for individual

NPDES permit limits are possible and

potentially efficient where the NPDES

discharger is the only point source

discharger to a specific water body.

The rule requires a default WER value

of 1.0 which will be assumed, if no sitespecific WER is determined. To use a

WER other than the default of 1.0, the

rule requires that the WER must be

determined as set forth in EPA’s WER

guidance or 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 rule

for California, does not completely

eliminate the utility of the WER. This is

particularly true for copper, a metal that

forms reduced-toxicity 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

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.

d. Saltwater Copper Criteria

The saltwater copper criteria for

aquatic life in today’s rule are 4.8 μg/l

(CMC) and 3.1 μg/l (CCC) in the

dissolved form. These criteria reflect

new data including data collected from

studies for the New York/New Jersey

Harbor and the San Francisco Bay

indicating a need to revise the former

copper 304(a) criteria guidance

document to reflect a change in the

saltwater CMC and CCC aquatic life

values. These data also reflect a

comprehensive literature search

resulting in 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 contains 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 today’s rule.

e. 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 criteria continuous

concentration, or 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 promulgating 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. The State may apply

to EPA for approval of an alternative

averaging period. To do so, the State

must submit to EPA the basis for such

alternative averaging period.

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

31692 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

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 (60 FR 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. 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.

EPA added language to the final rule

which will enable the State to adopt

alternative averaging periods and

frequencies and associated design flows

where appropriate. The State may apply

to EPA for approval of alternative

averaging periods and frequencies and

related design flows; the State must

submit the bases for any changes. Before

approving any change, EPA will publish

for public comment, a notice proposing

the changes.

f. 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 milligrams per liter (mg/l)

as calcium carbonate (CaCO3).

Section 131.38(b)(2) of the final 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

micrograms per liter (μg/l), respectively.

Thus, the specific value in the table in

the regulatory text is for illustrative

purposes only. Most of the data used to

develop these hardness equations for

deriving aquatic life 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 an even

more protective 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 promulgating today’s

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

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31693

toxicological 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 noncarcinogens.

If there are no data on how a chemical

agent causes cancer, EPA’s existing

human health guidelines assume that

carcinogenicity is a ‘‘non-threshold

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.

With existing criteria, 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.

Note: Recent changes in the Agency’s

cancer guidelines addressing these

assumptions are described in the Draft Water

Quality Criteria Methodology: Human

Health, 63 FR 43756, August 14, 1998.

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 doseresponse 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

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 either a No ObservedAdverse Effect Level (NOAEL), Lowest

Observed Adverse Effect Level (LOAEL),

or other benchmark 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. 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. Regarding

issues concerning criteria development

and differences in dose per kilogram of

body weight, RfDs are always derived

based on the most sensitive health effect

endpoint. Therefore, when that basis is

due to a chronic or lifetime health

effect, the exposure parameters assume

the exposed individual to be the average

adult, as indicated above.

In the absence of this final rule, there

may be particular risks to children. EPA

believes that children are protected by

the human health criteria contained in

this final rule. Children are protected

against other less sensitive adverse

health endpoints due to the

conservative way that the RfDs are

derived. An RfD is a public health

protective endpoint. It is an amount of

a chemical that can be consumed on a

daily basis for a lifetime without

expecting an adverse effect. RfDs are

based on sensitive health endpoints and

31694 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

are calculated to be protective for

sensitive human sub-populations

including children. If the basis of the

RfD was due to an acute or shorter-term

developmental effect, EPA uses

exposure parameters other than those

indicated above. Specifically, EPA uses

parameters most representative of the

population of concern (e.g., the health

criteria for nitrates based on infant

exposure parameters). For carcinogens,

the risk assessments are upper bound

one in a million (10¥6) lifetime risk

numbers. The risk to children is not

likely to exceed these upper bounds

estimates and may be zero at low doses.

The exposure assumptions for drinking

water and fish protect children because

they are conservative for infants and

children. EPA assumes 2 liters of

untreated surface water and 6.5 grams of

freshwater and estuarine fish are

consumed each day. EPA believes the

adult fish consumption assumption is

conservative for children because

children generally consume marine fish

not freshwater and estuarine.

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 uses 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 rule,

the IRIS values as of October 1996 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 rule is

contained in the administrative record.

For the human health criteria

included in today’s 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 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 1980 criteria

guidance document recommendations,

and those in this rule, but this rule

presents EPA’s most current CWA

section 304(a) criteria recommendation.

The basis (q1* or RfD) and BCF for each

pollutant criterion in today’s rule is

contained in the rule’s Administrative

Record Matrix which is included in the

administrative record for the 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 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-trans-dichloroethylene

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

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 promulgates

criteria for these nine pollutants:

copper

1, 2-dichloropropane

1,2-trans-dichloroethylene

2,4-dimethylphenol

acenaphthene

2-chloronaphthalene

N-nitrosodi-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 rule contains the specific RfDs,

q1*s, and BCFs used in calculating

these criteria.

Proposed Changes to the Human

Health Criteria Methodology: EPA

recently proposed revisions to the 1980

ambient water quality criteria derivation

guidelines (the Human Health

Guidelines). See Draft Water Quality

Criteria Methodology: Human Health,

63 FR 43756, August 14, 1998; see also

Draft Water Quality Criteria

Methodology: Human Health, U.S. EPA

Office of Water, EPA 822–Z–98–001.

The EPA revisions consist of five

documents: Draft Water Quality Criteria

Methodology: Human Health, EPA 822–

Z–98–001; Ambient Water Quality

Criteria Derivation Methodology Human

Health, Technical Support Document,

Final Draft, EPA–822–B–98–005; and

three Ambient Water Quality Criteria for

the Protection of Human Health,

Drafts—one each for Acrylonitrile, 1,3-

Dichloropropene (1,3-DCP), and

Hexachlorobutadiene (HCBD),

respectively, EPA–822–R–98–006, –005,

and –004. All five documents are

contained in the administrative record

for today’s rule.

The proposed methodology revisions

reflect significant scientific advances

that have occurred during the past

nineteen years in such key areas as

cancer and noncancer risk assessments,

exposure assessments and

bioaccumulation. For specific details on

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31695

these proposed changes and others,

please refer to the Federal Register

notice or the EPA document.

It should be noted that some of the

proposed changes may result in

significant numeric changes in the

ambient water quality criteria. However,

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 criteria methodology. The

existing criteria are still viewed as

scientifically acceptable by EPA. The

intention of the proposed 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

many years worth of development and

peer review, it is reasonable to assume

that revisiting all existing criteria, and

incorporating peer review into such

review, could require comparable

amounts of time and resources. Given

these circumstances, EPA proposed a

process for revisiting these criteria as

part of the overall revisions to the

methodology for deriving human health

criteria. This process is discussed in the

Implementation Section of the Notice of

Draft Revisions to the Methodology for

Deriving Ambient Water Quality Criteria

for the Protection of Human Health (see

63 FR 43771–43776, August 14, 1998).

The State of California in its Ocean

Plan, adopted in 1990 and approved by

EPA in 1991, established numeric 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 report prepared by the

State’s Pesticide and Environmental

Toxicology Section of the Office of

Environmental Health Hazard

Assessment of the California

Environmental Protection Agency. The

report, entitled, Chemicals in Fish

Report No. 1: Consumption of Fish and

Shellfish in California and the United

States, was published in final draft form

in July of 1997, and released to the

public on September 16, 1997. The

report is currently undergoing final

evaluation, and is expected to published

in final form in the near future. This

final draft report is contained in the

administrative record for today’s rule.

Although EPA has not used this fish

consumption value here because this

information has not yet been finalized,

the State may use 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 promulgating

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.

For National Pollutant Discharge

Elimination System (NPDES) purposes,

EPA supports the regulation of other

dioxin and dioxin-like compounds

through the use of toxicity equivalencies

or TEQs in NPDES permits (see

discussion below). For California

waters, if the discharge of dioxin or

dioxin-like compounds has reasonable

potential to cause or contribute to a

violation of a narrative criterion,

numeric water quality-based effluent

limits for dioxin or dioxin-like

compounds should be included in

NPDES permits and should be

expressed using a TEQ scheme.

EPA has been evaluating the health

threat posed by dioxin nearly

continuously for over two decades.

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 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 Assistant Administrator

for Water to Regional Water

Management Division 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 the Assistant

Administrator for Water to Regional

Water Management Division Directors,

dated January 5, 1990 (AR VA–66).

These documents are available in the

administrative record for today’s 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 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.

Thereafter, the Agency proceeded to

regulate dioxin in a number of

environmental programs, including

standards under the Safe Drinking

Water Act and the CWA.

The Administrator’s promulgation of

the dioxin human health criteria in the

1992 NTR affirmed the Agency’s

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 FR 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 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

31696 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

revised reassessment will go to the SAB

in the near future. With today’s rule, the

Agency 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 promulgates

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.

In 1994, the World Health

Organization (WHO) revised the TEF

scheme for dioxins and furans to

include toxicity from dioxin-like

compounds (Ahlborg et al., 1994).

However, no changes were made to the

TEFs for dioxins and furans. In 1998,

the WHO re-evaluated and revised the

previously established TEFs for dioxins

(Ds), furans (Fs) and dioxin-like

compounds (Vanden Bers, 1998). The

nomenclature for this TEF scheme is

TEQDFP–WHO98, where TEQ

represents the 2,3,7,8-TCDD Toxic

Equivalence of the mixture, and the

subscript DFP indicates that dioxins

(Ds) furans (Fs) and dioxin-like

compounds (P) are included in the TEF

scheme. The subscript 98 following

WHO displays the year changes were

made to the TEF scheme.

EPA intends to use the 1998 WHO

TEF scheme in the near future. At this

point however, EPA will support the

use of either the 1989 interim

procedures or the 1998 WHO TEF

scheme but encourages the use of the

1998 WHO TEF scheme in State

programs. EPA expects California to use

a TEF scheme in implementing the

2,3,7,8-TCDD water quality criteria

contained in today’s rule. The TEQ and

TEF approach provide a methodology

for setting NPDES water quality-based

permit limits that are protective of

human health for dioxin and dioxin-like

compounds.

Several commenters requested EPA to

promulgate criteria for other forms of

dioxin, in addition to 2,3,7,8-TCDD.

EPA’s draft reassessment for dioxin

examines toxicity based on the TEQ

concept and I–TEFs/89. When EPA

completes the dioxin reassessment, the

Agency intends to adopt revised 304(a)

water quality criteria guidance based on

the reassessment for dioxin. If

necessary, EPA will then act to amend

the NTR and CTR to reflect the revised

304(a) water quality criteria guidance.

b. Arsenic Criteria

EPA is not promulgating human

health criteria for arsenic in today’s

rule. EPA recognizes that it promulgated

human health water quality criteria for

arsenic for a number of States in 1992,

in the NTR, based on EPA’s 1980

section 304(a) criteria guidance for

arsenic established, in part, from IRIS

values current at that time. However, a

number of issues and uncertainties

existed at the time of the CTR proposal

concerning the health effects of arsenic.

These issues and uncertainties were

summarized in ‘‘Issues Related to

Health Risk of Arsenic’’ which is

contained in the administrative record

for today’s rule. During the period of

this rulemaking action, EPA

commissioned a study of arsenic health

effects by the National Research Council

(NRC) arm of the National Academy of

Sciences. EPA received the NRC report

in March of 1999. EPA scientists

reviewed the report, which

recommended that EPA lower the Safe

Drinking Water Act arsenic maximum

contaminant level (MCL) as soon as

possible (The arsenic MCL is currently

50 μg/l.) The bladder cancer analysis in

the NRC report will provide part of the

basis for the risk assessment of a

proposed revised arsenic MCL in the

near future. After promulgating a

revised MCL for drinking water, the

Agency plans to revise the CWA 304(a)

human health criteria for arsenic in

order to harmonize the two standards.

Today’s rule defers promulgating

arsenic criteria based on the Agency’s

previous risk assessment of skin cancer.

In the meantime, 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.

Permitting authorities may, among other

considerations, consider that value

when evaluating and interpreting

narrative water quality criteria.

c. Mercury Criteria

The human health criteria

promulgated 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 Guidance

(‘‘Guidance’’) incorporating

Bioaccumulation Factors (BAFs), but

rejected this approach for reasons

outlined below. The equation used here

to derive an ambient water quality

criterion for mercury from exposure to

organisms and water is:

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 x 10-4 mg/kg/day. The RfD

used a benchmark dose as an estimate

of a No Observed Adverse Effect Level

(NOAEL). The benchmark dose was

calculated by applying a Weibel model

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31697

for extra risk to all neurological effects

observed in 81 Iraqi children exposed in

utero as reported in Marsh, et. al. (1987).

Maternal hair mercury was the measure

of exposure. Extra risk refers to an

adjustment for background incidence of

a given health effect. Specifically, the

extra risk is the added incidence of

observing an effect above the

background rate relative to the

proportion of the population of interest

that is not expected to exhibit such as

effect. The resulting estimate was the

lower 95% statistical bound on the 10%

extra risk; this was 11 ppm mercury in

maternal hair. This dose in hair was

converted to an equivalent ingested

amount by applying a model based on

data from human studies; the resulting

benchmark dose was 1 x 10-3 mg/kg

body weight /day. The RfD was

calculated by dividing the benchmark

dose by a composite uncertainty factor

of 10. The uncertainty factor was used

to account for variability in the human

population, in particular the wide

variation in biological half-life of

methylmercury and the variation that is

observed in the ration of hair mercury

to mercury in the blood. In addition the

uncertainty factor accounts for lack of a

two-generation reproductive study and

the lack of data on long term effects of

childhood mercury exposures. The RfD

thus calculated is 1 x 10-4 mg/kg body

weight/day or 0.1 μg/kg/day. 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 bioconcentration factor or 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:

Weighted Average Practical BCF = (FC PBCF)

(FC)

× = + +

+ + = = ∑

∑

( . )( ) ( . )( ) ( . )( )

...

.

. . 0 00172 5500 0 00478 3765 0 0122 90000 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 promulgated 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 Guidance (‘‘Guidance’’). The

Guidance incorporated bioaccumulation

factors (BAFs) in the derivation of

criteria to protect human health because

it is believed that BAFs are a better

predictor than BCFs of the

concentration of a chemical within fish

tissue since BAFs include 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 Great Lakes Guidance

establishes a hierarchy of four methods

for deriving BAFs for non-polar organic

chemicals: (1) Field-measured BAFs; (2)

predicted BAFs derived using a fieldmeasured biota-sediment 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 Great

Lakes Guidance 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; therefore, today’s final rule does

not use the GLI BAF in establishing

human health criteria for mercury in

California. The magnitude of the BAF

for mercury in a given system depends

on how much of the total mercury is

present in the methylated form.

Methylation rates vary widely from one

water body to another for reasons that

are not fully understood. Lacking the

data, it is difficult to determine if the

BAF used in the GLI represents the true

potential for mercury to bioaccumulate

in California surface waters. The true,

average BAF for California could be

higher or lower. For more information

see EPA’s Response to Comments

document in the administrative record

for this rule (specifically comments

CTR–002–007(b) and CTR–016–007).

EPA is developing a national BAF for

mercury as part of revisions to its 304(a)

criteria for human health; however, the

BAF methodology that will be used is

currently under evaluation as part of

EPA’s revisions to its National Human

Health Methodology (see section F.3

above). EPA applied a similar

methodology in its Mercury Study

Report to Congress (MSRC) to derive a

BAF for methylmercury. The MSRC is

available through NTIS (EPA–452/R–

97–003). Although a BAF was derived

in the MSRC, EPA does not intend to

use this BAF for National application.

EPA is engaged in a separate effort to

incorporate additional mercury

bioaccumulation data that was not

considered in the MSRC, and to assess

uncertainties with using a National BAF

approach for mercury. Once the

proposed revised human health

methodology, including the BAF

component, is finalized, EPA will revise

its 304(a) criteria for mercury to reflect

changes in the underlying methodology,

recommendations contained in the

MSRC, and recommendations in a

National Academy of Science report on

human health assessment of

methylmercury. When EPA changes its

304(a) criteria recommendation for

mercury, States and Tribes will be

expected to review their water quality

standards for mercury and make any

revisions necessary to ensure their

standards are scientifically defensible.

New information may become

available regarding the bioaccumulation

31698 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

of mercury in certain water bodies in

California. EPA supports the use of this

information to develop site-specific

criteria for mercury. Further, if a

California water body is impaired due to

mercury fish tissue or sediment

contamination, loadings of mercury

could contribute to or exacerbate the

impairment. Therefore, one option

regulatory authorities should consider is

to include water quality-based effluent

limits (WQBELs) in permits based on

mass for discharges to the impaired

water body. Such WQBELs must be

derived from and comply with

applicable State water quality standards

(including both numeric and narrative

criteria) and assure that the discharge

does not cause or contribute to a

violation of water quality standards.

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/kgday 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 mixtures

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 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 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 three-fold over those using

central tendency. Upper bounds are

useful for estimating risks or setting

exposure-related 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. EPA

updated the human health criteria for

PCBs in the National Toxics Rule on

September 27, 1999. For today’s 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 = × ×

× ×

( , 1 000 g/mg)

q1* [WC + (FC BCF)]

μ

Where:

RF = Risk Factor = 1 x 10¥6

BW = Body Weight = 70 kg

q1* = Cancer slope factor = 2 per mg/

kg-day

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 = × ×

× ×

( , 1 000 g/mg)

q1* FC BCF

μ

Where:

RF = Risk Factor = 1 x 10¥6

BW = Body Weight = 70 kg

q1* = Cancer slope factor = 2 per mg/

kg-day

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 total PCBs. 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 today’s rule).

e. Excluded Section 304(a) Human

Health Criteria

As is the case in the NTR, as

amended, today’s rule does not

promulgate 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 those 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.

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31699

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.

As part of the proposed rule, EPA

requested and received comment on the

adoption of a 10 ¥5 risk level for

carcinogenic pollutants. The effect of a

10¥5 risk level would have been to

increase (i.e., make less stringent)

carcinogenic pollutant criteria values

(noted in the matrix by footnote c) that

are not already promulgated in the NTR,

by one order of magnitude. For example,

the 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 have been

0.13 μg/l. EPA received several

comments that indicated a preference

for a higher (10¥4 and 10¥5) risk level

for effluent dependent waters or other

types of special circumstances.

In today’s rule, EPA is promulgating

criteria that protect the general

population at an incremental cancer risk

level of one in a million (10¥6) for all

priority toxic pollutants regulated as

carcinogens, consistent with the criteria

promulgated in the NTR for the State of

California. 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, contained a

risk level of 10¥6 for most carcinogens.

The State has historically protected at a

10¥6 risk level for carcinogenic

pollutants.

EPA, in its recent human health

methodology revisions, proposed

acceptable lifetime cancer risk for the

general population in the range of 10¥5

to 10¥6. EPA also proposed that States

and Tribes ensure the most highly

exposed populations do not exceed a

10¥4 risk level. However, EPA’s draft

methodology revisions also stated that it

will derive 304(a) criteria at a 10¥6 risk

level, which the Agency believes

reflects the appropriate risk for the

general population and which applies a

risk management policy which ensures

protection for all exposed population

groups. (Draft Water Quality Criteria

Methodology: Human Health, EPA 822–

Z–98–001, August 1998, Appendix II,

page 72).

Subpopulations within a State may

exist, such as recreational and

subsistence anglers, who as a result of

greater exposure to a contaminant are at

greater risk than the standard 70

kilogram person eating 6.5 grams per

day of fish and shellfish and drinking

2.0 liters per day of drinking water with

pollutant levels meeting the water

quality criteria. EPA acknowledges that

at any given risk level for the general

population, those segments of the

population that are more highly exposed

face a higher relative risk. For example,

if fish are contaminated at a level

permitted by criteria derived on the

basis of a risk level of 10¥6, individuals

consuming up to 10 times the assumed

fish consumption rate would still be

protected at a 10¥5 risk level. Similarly,

individuals consuming 100 times the

general population rate would be

protected at a 10¥4 risk level. EPA,

therefore, believes that derivation of

criteria at the 10¥6 risk level is a

reasonable risk management decision

protective of designated uses under the

CWA. While outside the scope of this

rule, EPA notes that States and Tribes,

however, have the discretion to adopt

water quality criteria that result in a

higher risk level (e.g., 10¥5). EPA

expects to approve such criteria if the

State or Tribe has identified the most

highly exposed subpopulation within

the State or Tribe, demonstrates the

chosen risk level is adequately

protective of the most highly exposed

subpopulation, and has completed all

necessary public participation.

This demonstration has not happened

in California. Further, the information

that is available on highly exposed

subpopulations in California supports

the need to protect the general

population at the 10¥6 level. California

has cited the Santa Monica Bay Seafood

Consumption Study as providing the

best available data set for estimating

consumption of sport fish and shellfish

in California for both marine or

freshwater sources (Chemicals in Fish

Report No. 1: Consumption of Fish and

Shellfish in California and the United

States, Final Draft Report, July 1997).

Consumption rates of sport fish and

shellfish of 21g/day, 50 g/day, 107 g/

day, and 161 g/day for the median,

mean, 90th, and 95th percentile rates,

respectively, were determined from this

study. Additional consumption of

commercial species in the range of

approximately 8 to 42 g/day would

further increase these values. Clearly the

consumption rates for the most highly

exposed subpopulation within the State

exceeds 10 times the 6.5 g/day rates

used in the CTR. Therefore, use of a risk

level of 10¥5 for the general population

would not be sufficient to protect the

most highly exposed population in

California at a 10¥4 risk level. On the

other hand, even the most highly

exposed subpopulations cited in the

California study do not have

consumption rates approaching 100

times the 6.5 g/day rates used in the

CTR. The use of the 10¥6 risk level to

protect average level consumers does

not subject these subpopulations to risk

levels as high as 10¥4.

EPA believes its decision to establish

a 10¥6 risk level for the CTR is also

consistent with EPA’s policy in the NTR

to select the risk level that reflect the

policies or preferences of CWA

programs in the affected States.

California adopted standards for priority

toxic pollutants for its ocean waters in

1990 using a 10¥6 risk level to protect

human health (California Ocean Plan,

1990). In April 1991, and again in

November 1992, California adopted

standards for its inland surface waters

and enclosed bays and estuaries in its

Inland Surface Waters Plan (ISWP) and

its Enclosed Bays and Estuaries Plan

(EBEP) using a 10¥6 risk level. To be

consistent with the State’s water quality

standards, EPA used a 10¥6 risk level

for California in the NTR at 57 FR

60867. The State has continued using a

10¥6 risk level to protect human health

for its standards that were not

withdrawn with the ISWP and EBEP.

The most recent expression of risk level

preference is contained in the Draft

Functional Equivalent Document,

Amendment of the Water Quality

Control Plan for Ocean Waters of

California, October 1998, where the

State recommended maintaining a

consistent risk level of 10¥6 for the

human health standards that it was

proposing to revise.

EPA received several comments

requesting a 10¥5 risk level based on the

risk level chosen for the Great Lakes

Water Quality Guidance (the Guidance).

There are several differences between

the guidelines for the derivation of

human health criteria contained in the

Guidance and the California Toxics Rule

(CTR) that make a 10¥5 risk factor

appropriate for the Guidance, but not for

the CTR. These differences result in

criteria developed using the 10¥5 risk

factor in the Guidance being at least as

stringent as criteria derived under the

CTR using a 10¥6 risk factor. The

relevant aspects of the Guidance

include:

• Use of fish consumption rates that

are considerably higher than fish

consumption rates for the CTR.

• Use of bioaccumulation factors

rather than bioconcentration factors in

31700 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

estimating exposure, considerably

increasing the dose of carcinogens to

sensitive subgroups.

• Consideration of additivity of

effects of mixtures for both carcinogenic

and noncarcinogenic pollutants.

This combination of factors increase

the calculated carcinogenic risk

substantially under the Guidance (the

combination would generally be more

than one order of magnitude), making a

lower overall risk factor acceptable. The

Guidance risk factor provides, in fact,

criteria with at least the same level of

protection against carcinogens as

criteria derived with a higher risk factor

using the CTR. A lower risk factor for

the CTR would not be appropriate

absent concomitant changes in the

derivation procedures that provide

equivalent risk protection.

G. Description of Final Rule

1. Scope

Paragraph (a) in 40 CFR 131.38,

entitled ‘‘Scope,’’ states that this rule is

a promulgation of criteria for priority

toxic pollutants in the State of

California for inland surface waters,

enclosed bays, and estuaries. Paragraph

(a) in 40 CFR 131.38 also states that this

rule contains an authorizing compliance

schedule provision.

2. EPA Criteria for Priority Toxic

Pollutants

EPA’s criteria for California are

presented in tabular form at 40 CFR

131.38. For ease of presentation, the

table that appears combines water

quality criteria promulgated in the NTR,

as amended, that are outside the scope

of this rulemaking, with the criteria that

are within the scope of today’s rule.

This is intended to help readers

determine applicable water quality

criteria for the State of California. The

table contains footnotes for clarification.

Paragraph (b) in 40 CFR 131.38

presents a matrix of the applicable EPA

aquatic life and/or human health criteria

for priority toxic pollutants in

California. 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

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

40 CFR 131.38(b) contains human

health criteria in Column D for 92

priority toxic pollutants which are

divided into Column 1: criteria 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 Column 2: criteria for aquatic

organism consumption only. 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 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

promulgating 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 rule at 40 CFR 131.38(b).

Another reason is that EPA is

promulgating 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 23 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.

The final rule at 40 CFR 131.38(c)

establishes the applicability of the

criteria to the State of California. 40 CFR

131.38(d) is described later in Section F,

of this preamble. EPA has included in

this rule provisions necessary to

implement numeric criteria in a way

that maintains the level of protection

intended. These provisions are included

in 40 CFR 131.38(c) of today’s 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 analyses 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

adequacy of the criteria for priority toxic

pollutants.) EPA recommended either of

two methods for calculating acceptable

low flows, the traditional hydrologic

method developed by the U.S.

Geological Survey or 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 quality-based 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. EPA believes it is

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31701

important to specify design flows in

today’s rule so that, in the absence of

state design flows, the criteria

promulgated 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.

The low flows specified in the rule

explicitly contain duration and

frequency of occurrence which

represent certain probabilities of

occurrence. Likewise, the criteria for

priority toxic pollutants are defined

with duration and frequency

components. Dynamic modeling

techniques explicitly predict the effects

of variability in receiving water, effluent

flow, and pollution variation. Dynamic

modeling techniques, as described in

the TSD, allow for calculating wasteload

allocations that meet the criteria for

priority toxic pollutants without using a

single, worst-case concentration based

on a critical condition. Either dynamic

modeling or steady state modeling can

be used to implement the criteria

promulgated today. For simplicity, only

steady state conditions are discussed

here. Clearly, if the criteria were

implemented using design flows that are

too high, the resulting toxic controls

would not be adequate, because the

resulting ambient concentrations would

exceed EPA’s criteria.

In the case of aquatic life, assuming

exceedences occur more frequently than

once in three 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:

Type of criteria Design flow

Acute Aquatic Life

(CMC).

1 Q 10 or 1 B 3

Chronic Aquatic Life

(CCC).

7 Q 10 or 4 B 3

Human Health ........... 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 exceedences for 4

consecutive days once every 3 years.

It is determined by EPA’s

computerized method (DFLOW

model);

EPA is requiring that the harmonic

mean flow be applied with human

health criteria. 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.)

All waters (including lakes, estuaries,

and marine waters), whether or not

suitable for such hydrologic

calculations, are subject to the criteria

promulgated today. Such criteria will

need to be attained at the end of the

discharge pipe, unless the State

authorizes a mixing zone. Where the

State plans 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

promulgated 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 based on the actual

criteria necessary to protect aquatic life

and human health become measurable.

The Agency does not believe it is

appropriate to promulgate criteria that

are not sufficiently protective. EPA

discusses this issue further in its

Response to Comment Document for

today’s final rule.

EPA does believe, however, that the

use of analytical detection limits are

appropriate for assessing compliance

with National Pollutant Discharge

Elimination System (NPDES) permit

limits. This view of the role of detection

limits was first articulated in guidance

for translating dioxin criteria into

NPDES permit limits. 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 presented a

model for addressing toxic pollutants

which have criteria less than current

detection limits. EPA, in more recent

guidance, recommends the use of the

‘‘minimum level’’ or ML for reporting

sample results to assess compliance

with WQBELs (TSD page 111). The ML,

also called the ‘‘quantification level,’’ is

the level at which the entire analytical

system gives recognizable mass spectra

and acceptable calibration points, i.e.,

the point at which the method can

reliably quantify the amount of

pollutant in the sample. States can use

their own procedures to average and

otherwise account for monitoring data,

e.g., quantifying results below the ML.

These results can then be used to assess

compliance with WQBELs. (See 40 CFR

part 132, Appendix F, Procedure 8.B.)

This approach is applicable to priority

toxic pollutants with criteria less than

current detection limits. EPA’s guidance

explains that standard analytical

methods may be used for purposes of

assessing 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 assessments. Because

of the function of water quality criteria,

EPA has not considered the sensitivity

of analytical methods in deriving the

criteria promulgated today.

EPA has promulgated 40 CFR

131.38(c)(3) to determine when

freshwater or saltwater aquatic life

criteria apply. This provision

incorporates a time parameter to better

define the critical condition. The

structure of the paragraph is to establish

31702 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

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.

Paragraph (d) in 40 CFR 131.38 lists

the designated water and use

classifications for which the 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.

Exceedences 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, today’s

rule requires that the acute criterion for

a pollutant be exceeded no more than

once in three years on the average. EPA

is also requiring that the chronic

criterion for a pollutant be exceeded no

more than once in three years on the

average. EPA acknowledges that States

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 where EPA is

promulgating criteria.

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 an average recurrence

frequency of once in ten years), and

applies the CCC at the 7Q10 design flow

(i.e., the lowest average seven

consecutive day flow with a recurrence

frequency of once 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.

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. EPA has not

yet completed this work. Until this work

is complete, EPA believes that where

EPA promulgates criteria, 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).

Since the publication of the proposed

CTR, the State of California adopted

procedures which detail how water

quality criteria will be implemented

through NPDES permits, waste

discharge requirements, and other

regulatory approaches. These

procedures entitled, Policy for

Implementation of Toxics Standards for

Inland Surface Waters, Enclosed Bays,

and Estuaries of California were

adopted on March 2, 2000. Once these

procedures are submitted for review

under CWA section 303(c), EPA will

review them as they relate to water

quality standards, and approve or

disapprove them.

Several commenters understood the

language in the preamble to the

proposed rule regarding implementation

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31703

to mean that site-specific criteria,

variances, and other actions would be

prohibited or severely limited by the

CTR. Site-specific criteria, variances and

other actions modifying criteria are

neither prohibited nor limited by the

CTR. The State, if it so chooses, still can

make these changes to its water quality

standards, subject to EPA approval.

However, with this Federal rule in

effect, the State cannot implement any

modifications that are less stringent

than the CTR without an amendment to

the CTR to reflect these modifications.

EPA will make every effort to

expeditiously accommodate Federal

rulemaking of appropriate modifications

to California’s water quality standards.

In the preamble to the proposed CTR,

and here today, EPA is emphasizing that

these efforts to amend the CTR on a

case-by-case basis will generally

increase the time before a modification

can be implemented.

4. Wet Weather Flows

EPA has for a longtime maintained

that CWA section 301(b)(1)(C) applies to

NPDES permits for discharges from

municipal separate storm sewer

systems. Recently, the U.S. Court of

Appeals for the Ninth Circuit upheld

NPDES permits issued by EPA for five

Arizona municipal separate storm sewer

systems and addressed this issue

specifically. Defenders of Wildlife, et al.

v. Browner, No. 98–71080 (9th Cir.,

October 1999). The Court held that the

CWA does not require ‘‘strict

compliance’’ with State water quality

standards for municipal storm sewer

permits under section 301(b)(1)(C), but

that at the same time, the CWA does

give EPA discretion to incorporate

appropriate water quality-based effluent

limitations under another provision,

CWA section 402(p)(3)(B)(iii).

The Court based its decision on the

structure of section 402(p)(3), which

contains distinct language for discharges

of industrial storm water and municipal

storm water. In section 402(p)(3)(A),

Congress requires that ‘‘dischargers

associated with industrial activity shall

meet all applicable provisions of

[section 402] and section [301].’’ 33

U.S.C. section 1342(p)(3)(A). The Court

noted, therefore, that by incorporation,

industrial storm water discharges need

to achieve ‘‘any more stringent

limitation, including those necessary to

meet water quality standards * * *’’

The Court explained that industrial

storm water discharges ‘‘must comply

strictly with State water quality

standards’’ but that Congress chose not

to include a similar provision for

municipal storm sewer discharges,

including instead a requirement for

controls to reduce pollutants to the

maximum extent practicable or MEP

standard in section 402(p)(3)(B).

Reading the two related sections

together, the Court concluded that

section 402(p)(3)(B)(iii) does not require

‘‘strict compliance’’ by municipal storm

sewer discharges according to section

301(b)(1)(C). At the same time, however,

the Court found that the language in

CWA section 402(p)(3)(B)(iii) which

states that permits for discharges from

municipal storm sewers shall require

‘‘such other provisions as the

Administrator of the state determines

appropriate for the control of such

pollutants’’ provides EPA with

discretion to incorporate provisions

lending to ultimate compliance with

water quality standards.

EPA believes that compliance with

water quality standards through the use

of Best Management Practices (BMPs) is

appropriate. EPA articulated its position

on the use of BMPs in storm water

permits in the policy memorandum

entitled, ‘‘Interim Permitting Approach

for Water Quality-Based Effluent

Limitations In Storm Water Permits’’

which was signed by the Assistant

Administrator for Water, Robert

Perciasepe on August 1, 1996 (61 FR

43761, August 9, 1996). A copy of this

memorandum is contained in the

administrative record for today’s rule.

The policy affirms the use of BMPs as

a means to attain water quality

standards in municipal storm water

permits, and embraces BMPs as an

interim permitting approach.

The interim permitting approach uses

BMPs in first-round storm water

permits, and expanded or better-tailored

BMPs in subsequent permits, where

necessary, to provide for the attainment

of water quality standards. In cases

where adequate information exists to

develop more specific conditions or

limitations to meet water quality

standards, these conditions or

limitations are to be incorporated into

storm water permits, as necessary and

appropriate.

This interim permitting approach,

however, only applies to EPA. EPA

encourages the State to adopt a similar

policy for municipal storm water

permits. This interim permitting

approach provides time, where

necessary, to more fully assess the range

of issues and possible options for the

control of storm water discharges for the

protection of water quality. More

information on this issue is included in

the response to comment document in

response to specific storm water issues

raised by commenters.

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

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. An authorizing

compliance schedule provision is

included in today’s rule because of the

potential for existing dischargers to have

new or more stringent effluent

limitations for which immediate

compliance would not be possible or

practicable.

New and Existing Dischargers: The

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 commences after

the effective date of this regulation.’’

These definitions are modeled 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 are reissued

or modified to contain new or more

stringent limitations based upon certain

water quality requirements, the permit

could allow up to five years, or up to the

length of a permit, 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

31704 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

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.

Today’s 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:

Today’s 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

an extended schedule is warranted.

EPA’s regulations at 122.47 require

compliance with standards as soon as

possible. This means that permit

authorities should not allow compliance

schedules where the permittee fails to

demonstrate their necessity. This

provision should not 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. See the preamble

to the proposed rule.

Under this rule, 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 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 to contain more

stringent limits based on the water

quality criteria in today’s rule. Such

compliance schedules, however, cannot

be extended to any indefinite point of

time in the future because the

compliance schedule provision in this

rule will sunset on May 18, 2005. The

sunset applies to the authorizing

provision in today’s rule (40 CFR

131.38(e)), not to individual schedules

of compliance included in specific

NPDES permits. 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. This

would occur where the permit authority

includes the single maximum five-year

compliance schedule in a permit that is

reissued just before the compliance

schedule provision sunsets (having been

previously issued without WQBELS

using the rule’s criteria on the eve of the

effective date of this rule). Instead, the

effect of the sunset provision is to limit

the longest time period for compliance

to ten years after 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

contained in the permit 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.

EPA would prefer that the State adopt

an authorizing compliance schedule

provision but recognizes that the State

may not be able to complete this action

for some time after promulgation of the

CTR. Thus, EPA has chosen to

promulgate the rule with a sunset

provision which states that the

authorizing compliance schedule

provision will cease or sunset on May

18, 2005. However, if the State Board

adopts, and EPA approves, a statewide

authorizing compliance schedule

provision significantly prior to May 18,

2005, EPA will act to stay the

authorizing compliance schedule

provision in today’s rule. Additionally,

if a Regional Board adopts, and the State

Board adopts and EPA approves, a

Regional Board authorizing compliance

schedule provision, EPA will act to stay

today’s provision for the appropriate or

corresponding geographic region in

California. At that time, the State

Board’s or Regional Board’s authorizing

compliance schedule provision will

govern the ability of the State regulatory

entity to allow a discharger to include

a compliance schedule in a discharger’s

NPDES permit.

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 effort to

readopt statewide water quality control

plans, or in adopting individual basinwide 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, two RWQCBs have

adopted an authorizing compliance

schedule provision as an amendment to

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31705

their respective Basin Plans during the

Boards’ last triennial review process.

The Basin Plans have been adopted by

the State and have come to EPA for

approval. Thus, the Basin Plans’

provisions are effective for the

respective Basins. If and when EPA

approves of either Regional Basin Plan,

EPA will expeditiously act to amend the

CTR, staying its compliance schedule

provision, for the appropriate

geographic region.

6. Changes From Proposed Rule

A few changes were made in the final

rule from the proposal both as a result

of the Agency’s consideration of issues

raised in public comments and

Endangered Species Act consultation

with the U.S. Fish and Wildlife Service

(FWS) and U.S. National Marine

Fisheries Service (NMFS). The

important changes include: reserving

the mercury aquatic life criteria;

reserving the selenium freshwater acute

aquatic life criterion; reserving the

chloroform human health criteria; and

adding a sunset provision to the

authorizing compliance schedule

provision. EPA also clarified that the

CTR will not replace priority toxic

pollutant criteria which were adopted

by the San Francisco Regional Water

Quality Control Board in its 1986 Basin

Plan, adopted by the State Board, and

approved by EPA; specifying the

harmonic mean for human health

criteria for non-carcinogens and adding

a provision which explicitly allows the

State to adopt and implement an

alternative averaging period, frequency,

and design flow for a criterion after

opportunity for public comment.

The first two changes, the reservation

of mercury criteria and selenium

criterion, are discussed in more detail

below in Section L., The Endangered

Species Act (ESA). The selenium

criterion is also discussed in more detail

above in Section E., Derivation of

Criteria, in subsection 2.b., Freshwater

Acute Selenium Criterion. EPA has also

decided to reserve a decision on

numeric criteria for chloroform and

therefore not promulgate chloroform

criteria in the final rule. As part of a

large-scale regulation promulgated in

December l998 under the Safe Drinking

Water Act, EPA published a healthbased goal for chloroform (the

maximum contaminant level goal or

MCLG) of zero, see 63 FR 69390, Dec.

16, 1998. EPA provided new data and

analyses concerning chloroform for

public review and comment, including

a different, mode of action approach for

estimating the cancer risk, 63 FR 15674,

March 31, 1998, but did not reach a

conclusion on how to use that new

information in establishing the final

MCLG, pending further review by the

Science Advisory Board. EPA has now

concluded that any further actions on

water quality criteria should take into

account the new data and analysis as

reviewed by the SAB. This decision is

consistent with a recent federal court

decision vacating the MCLG for

chloroform (Chlorine Chemistry Council

v. EPA, No. 98–1627 (DC Cir., Mar.

31,2000)). EPA intends to reassess the

human health 304(a) criteria

recommendation for chloroform. For

these reasons, EPA has decided to

reserve a decision on numeric criteria

for chloroform in the CTR and not

promulgate water quality criteria as

proposed. Permitting authorities in

California should continue to rely on

existing narrative criteria to establish

effluent limitations as necessary for

chloroform.

The sunset provision for the

authorizing compliance schedule

provision has been added to ease the

transition from a Federal provision to

the State’s provision that was adopted

in March 2000 as part of its’ new

statewide implementation plan. The

sunset provision is discussed in more

detail in Section G.5 of today’s

preamble. The CTR matrix at 40 CFR

131.38(b)(1) makes it explicit that the

rule does not supplant priority toxic

pollutant criteria which were adopted

by the San Francisco Regional Water

Quality Control Board in its 1986 Basin

Plan, adopted by the State Board, and

approved by EPA. This change is

discussed more fully in Section D.4. of

today’s preamble. EPA modified the

design flow for implementing human

health criteria for non-carcinogens from

a 30Q5 to a harmonic mean. Human

health criteria for non-carcinogens are

based on an RfD, which is an acceptable

daily exposure over a lifetime. EPA

matched the criteria for protection over

a human lifetime with the longest

stream flow averaging period, i.e., the

harmonic mean. Lastly, the CTR now

contains language which is intended to

make it easier for the State to adopt and

implement an alternative averaging

period, frequency and related design

flow, for situations where the default

parameters are inappropriate. This

language is found at 40 CFR

131.38(c)(2)(iv).

H. Economic Analysis

This final rule establishes ambient

water quality criteria which, by

themselves, do not directly impose

economic impacts (see section K). These

criteria combined with the Stateadopted designated uses for inland

surface waters, enclosed bays and

estuaries, and implementation policies,

will establish water quality standards.

Until the State implements these water

quality standards, there will be no effect

of this rule on any entity. The State will

implement these criteria by ensuring

that NPDES permits result in discharges

that will meet these criteria. In so doing,

the State will have considerable

discretion.

EPA has analyzed the indirect

potential costs and benefits of this rule.

In order to estimate the indirect costs

and benefits of the rule, an appropriate

baseline must be established. The

baseline is the starting point for

measuring incremental costs and

benefits of a regulation. The baseline is

established by assessing what would

occur in the absence of the regulation.

At present, State Basin Plans contain a

narrative water quality criterion stating

that all waters shall be maintained free

of toxic substances in concentrations

that produce detrimental physiological

responses in human, plant, animal, or

aquatic life. EPA’s regulation at 40 CFR

122.44(d)(1)(vi) requires that where a

discharge causes or has the reasonable

potential to cause an excursion above a

narrative criterion within a State water

quality standard, the permitting

authority must establish effluent limits

but may determine limits using a

number of options. These options

include establishing ‘‘effluent limits on

a case-by-case basis, using EPA’s water

quality criteria published under section

304(a) of the CWA, supplemented where

necessary by other relevant

information’’ (40 CFR

122.44(d)(1)(vi)(B)). Thus, to the extent

that the State is implementing its

narrative criteria by applying the CWA

section 304(a) criteria, this rule does not

impose any incremental costs because

the criteria in this rule are identical to

the CWA section 304(a) criteria.

Alternatively, to the extent that the State

is implementing its narrative criteria on

a ‘‘case-by-case basis’’ using ‘‘other

relevant information’’ in its permits this

rule may impose incremental indirect

costs because the criteria in these

permits may not be based on CWA

304(a) criteria. Both of these approaches

to establishing effluent limits are in full

compliance with the CWA.

Because a specific basis for effluent

limits in all existing permits in

California is not known, it is not

possible to determine a precise estimate

of the indirect costs of this rule. The

incremental costs of the rule may be as

low as zero, or as high as $61 million.

The high estimate of costs is based on

the possibility that most of the effluent

limits now in effect are not based on

304(a) criteria. EPA evaluated these

31706 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

indirect costs using two different

approaches. The first approach uses

existing discharge data and makes

assumptions about future State NPDES

permit limits. Actual discharge levels

are usually lower than the level set by

current NPDES permit limits. This

approach, representing the low-end

scenario, also assumes that some of the

discretionary mechanisms that would

enhance flexibility (e.g., site specific

criteria, mixing zones) would be granted

by the State. The second approach uses

a sample of existing permit limits and

assumes that dischargers are actually

discharging at the levels contained in

their permits and makes assumptions

about limits statewide that would be

required under the rule. This approach,

representing the high-end scenario, also

assumes that none of the discretionary

mechanisms that would enhance

flexibility (e.g., site specific criteria,

mixing zones) would be granted by the

State. These two approaches recognize

that 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. To account for the uncertainty

of EPA’s implementation 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 potentially

affected by State implementation of

water quality standards in the NPDES

permit program. The costs and benefits

sections that follow summarize the

methodology and results of the analysis.

1. Costs

EPA assessed the potential

compliance costs that facilities may

incur to meet permit limits based on the

criteria in today’s rule. The analysis

focused on direct compliance costs such

as capital costs and operation and

maintenance costs (O&M) for end-ofpipe 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. In the EA for the

proposed CTR, 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 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.

In the EA for today’s final rule, EPA

primarily used the same sample as the

EA for the proposed rule with some

modifications. EPA increased the

number of minor POTWs and minor

industrial facilities in the sample. EPA

randomly selected four new minor

POTW facilities and five new minor

industrial facilities to add to the sample.

The number of sample facilities selected

in each area under the jurisdiction of a

Regional Water Quality Control Board

was roughly proportional to the

universe of facilities in each area.

For those facilities that were projected

to exceed permit limits based on the

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 ‘‘highend’’ cost scenario—to account for a

range of regulatory flexibility available

to the State when implementing permit

limits based on the water quality

criteria. The assumptions for baseline

loadings also vary over the two

scenarios. The low-end 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.

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 criteria are

estimated to be between $33.5 million

and $61 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. In addition, both the

high-end and low-end cost estimates in

the EA may be slightly overstated since

potential costs incurred to reduce

chloroform discharges were included in

these estimates. EPA made a decision to

reserve the chloroform human health

criteria after the EA was completed.

Under the low-end cost scenario,

major industrial facilities and POTWs

would incur about 27 percent of the

potential costs, indirect dischargers

would incur about 70 percent of the

potential costs, while minor dischargers

would incur about 3 percent. Of the

major direct dischargers, POTWs would

incur the largest share of projected costs

(87 percent). However, distributed

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31707

among 128 major POTWs in the State,

the average cost per plant would be

$61,000 per year. Chemical and

petroleum industries would incur the

highest cost of the industrial categories

(5.6 percent of the annual costs, with an

annual average of $25,200 per plant).

About 57 percent of the low-end costs

would be associated with pollution

prevention activities, while nearly 38

percent would be associated with

pursuing alternative methods of

compliance under the regulations.

Under the high-end cost scenario,

major industrial facilities and POTWs

would incur about 94 percent of the

potential costs, indirect dischargers

would incur about 17 percent of the

potential costs, while minor dischargers

would incur about 5 percent. Among the

major, direct dischargers, two categories

would incur the majority of potential

costs—major POTWs (82 percent),

Chemical/Petroleum Products (9

percent). The average annual per plant

cost for different industry categories

would ranges from zero to $324,000.

The two highest average cost categories

would be major POTWs ($324,000 per

year) and Chemical/Petroleum Products

($221,264 per year). The shift in

proportion of potential costs between

direct and indirect dischargers is due to

the assumption that more direct

dischargers would use end-of-pipe

treatment under the high-end scenario.

Thus, a smaller proportion of indirect

dischargers would be impacted under

the high-end scenario, since some

municipalities are projected to add endof-pipe treatment which would reduce

the need for controls from indirect

discharges. Over 91 percent of the

annual costs are for waste minimization

and treatment optimization costs. Waste

minimization would represent nearly

84% of the total annual costs. Capital

and operation and maintenance costs

would make up less than 9 percent of

annual costs.

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

projected annual costs of implementing

permit limits based on water quality

standards using today’s 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 criteria would be responsible

for the reduction of about 1.1 million to

2.7 million toxic pound-equivalents per

year, or 15 to 50 percent of the toxicweighted baseline loadings for the highand low-end scenarios, respectively.

The cost-effectiveness of the scenarios

would range from $22 (high-end

scenario) to $31 (low-end scenario) per

pound-equivalent.

2. 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 criteria. To

the extent feasible, empirical estimates

of the potential magnitude of the

benefits were developed and then

compared to the estimated costs of

implementing water quality standards

based on today’s 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

apply 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 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

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 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 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 criteria.

Total monetized annual benefits were

estimated in the range of $6.9 to $74.7

million. By category, annual benefits

would be $1.3 to $4.6 million for

avoided cancer risk, $2.2 to $15.2

million for recreational angling, and

$3.4 to $54.9 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 pre- or post-rule

31708 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

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

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. In

addition, benefit estimates in the EA

may be slightly overstated since

potential benefits from reductions in

chloroform discharges were included in

these estimates. EPA made a decision to

reserve the chloroform human health

criteria after the EA was completed.

EPA received a number of comments

which requested the Agency use the

cost-benefit analysis in the EA as a

factor in setting water quality criteria.

EPA does not use the EA as a basis in

determining protective water quality

criteria. EPA’s current regulations at 40

CFR 131.11 state that the criteria must

be based on sound scientific rationale

and must protect the designated use.

From the outset of the water quality

standards program, EPA has explained

that while economic factors may be

considered in designating uses, they

may not be used to justify criteria that

are not protective of those uses. 44 FR

25223–226, April 30, 1979. See e.g.

Mississippi Commission on Natural

Resources v. Costle, 625 F. 2d 1269,

1277 (5th Cir. 1980). EPA reiterated this

interpretation of the CWA and its

implementing regulations in discussing

section 304(a) recommended criteria

guidance stating that ‘‘they are based

solely on data and scientific judgments

on the relationship between pollutant

concentrations and environmental and

human health effects and do not reflect

consideration of economic impacts or

the technological feasibility of meeting

the chemical concentrations in ambient

water.’’ 63 FR 36742 and 36762, July 7,

1998.

I. Executive Order 12866, Regulatory

Planning and Review

Under Executive Order 12866 (58 FR

51735, 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

12866 and is therefore not subject to

OMB review.

J. Unfunded Mandates Reform Act of

1995

Title II of the Unfunded Mandates

Reform Act of 1995 (UMRA), Public

Law 104–4, establishes requirements for

Federal agencies to assess the effects of

their regulatory actions on State, local,

and tribal governments and the private

sector. Under section 202 of the UMRA,

EPA generally must prepare a written

statement, including a cost-benefit

analysis, for proposed and final rules

with ‘‘Federal mandates’’ that may

result in expenditures to State, local,

and tribal governments, in the aggregate,

or to the private sector, of $100 million

or more in any one year. Before

promulgating any regulation for which a

written statement is needed, section 205

of the UMRA generally requires EPA to

identify and consider a reasonable

number of regulatory alternatives and

adopt the least costly, most costeffective or least burdensome alternative

that achieves the objectives of the rule.

The provisions of section 205 do not

apply when they are inconsistent with

applicable law. Moreover, section 205

allows an Agency to adopt an

alternative other than the least costly,

most cost-effective or least burdensome

alternative if the Administrator

publishes with the final rule an

explanation why that alternative was

not adopted. Before EPA establishes any

regulatory requirements that may

significantly or uniquely affect small

governments, including tribal

governments, it must have developed

under section 203 of the UMRA a small

government Agency plan. The plan

must provide for 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 EPA informing, educating, and

advising small governments on

compliance with the regulatory

requirements.

Today’s rule contains no Federal

mandates (under the regulatory

provisions of Title II of the Unfunded

Mandates Reform Act (UMRA)) for

State, local, or tribal governments or the

private sector. Today’s rule imposes no

enforceable duty on any State, local or

Tribal governments or the private sector;

rather, the CTR promulgates ambient

water quality criteria which, when

combined with State-adopted uses, will

create water quality standards for those

water bodies with adopted uses. The

State will then use these resulting water

quality standards in implementing its

existing water quality control programs.

Thus, today’s rule is not subject to the

requirements of sections 202 and 205 of

the UMRA.

EPA has determined that this rule

contains no regulatory requirements that

might significantly or uniquely affect

small governments. This rule establishes

ambient water quality criteria which, by

themselves do not directly impact any

entity. The State will implement these

criteria by ensuring that NPDES permits

result in discharges that will meet these

criteria. In so doing, the State will have

considerable discretion. Until the State

implements these water quality

standards, there will be no effect of this

rule on any entity. Thus, today’s rule is

not subject to the requirements of

section 203 of UMRA.

K. Regulatory Flexibility Act

The Regulatory Flexibility Act

generally requires Federal agencies to

prepare a regulatory flexibility analysis

of any rule subject to notice and

comment rulemaking requirements

under the Administrative Procedure Act

or any other statute unless the Agency

certifies that the rule will not have a

significant economic impact of a

substantial number of small entities.

Small entities include small businesses,

small organizations, and small

governmental jurisdictions. For

purposes of assessing the impacts of

today’s rule on small entities, small

entity is defined as: (1) A small business

according to RFA default definitions for

small businesses (based on SBA size

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31709

standards); (2) a small governmental

jurisdiction that is a government of a

city, county, town, school district or

special district with a population of less

than 50,000; and (3) a small

organization that is any not-for-profit

enterprise which is independently

owned and operated and is not

dominant in its field.

After considering the economic

impacts of today’s final rule on small

entities, I certify that this action will not

have a significant economic impact on

a substantial number of small entities.

This final rule will not impose any

requirements on small entities.

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 NPDES

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, in turn, implements through the

NPDES permit process. The State has

considerable discretion in deciding how

to meet the water quality standards and

in developing discharge limits as

needed to meet the standards. In

circumstances where there is more than

one discharger to a water body that is

subject to water quality standards or

criteria, a State also has discretion in

deciding on the appropriate limits for

the different dischargers. While the

State’s implementation of federallypromulgated water quality criteria or

standards may result indirectly in new

or revised discharge limits for 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 include limits as

necessary to meet the water quality

standards established by the criteria in

today’s 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.

The RFA requires analysis of the

economic impact of a rule only on the

small entities subject to the rule’s

requirements. Courts have consistently

held that the RFA imposes no obligation

on an Agency to prepare a small entity

analysis of the effect of a rule on entities

not regulated by the rule. Motor &

Equip. Mrfrs. Ass’n v. Nichols, 142 F.3d

449, 467 & n.18 (D.C. Cir. 1998)(quoting

United States Distribution Companies v.

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

1996); see also American Trucking

Association, Inc. v. EPA, 175 F.3d 1027

(D.C. Cir. 1999). This final rule will

have a direct effect only on the State of

California which is not a small entity

under the RFA. Thus, individual

dischargers, including small entities, are

not directly subject to the requirements

of the rule. Moreover, because of

California’s discretion in implementing

these standards, EPA cannot assess the

extent to which the promulgation of this

rule may subsequently affect any

dischargers, including small entities.

Consequently, certification under

section 605(b) is appropriate. State of

Michigan, et al. v. U.S. Environmental

Protection Agency, No. 98–1497 (D.C.

Cir. Mar. 3, 2000), slip op. at 41–42.

L. Paperwork Reduction Act

This action requires no new or

additional information collection,

reporting, or record keeping subject to

the Paperwork Reduction Act, 44 U.S.C.

3501 et seq.

M. Endangered Species Act

Pursuant to section 7(a) of the

Endangered Species Act (ESA), EPA has

consulted with the U.S. Fish and

Wildlife Service and the U.S. National

Marine Fisheries Service (collectively,

the Services) concerning EPA’s

rulemaking action for the State of

California. EPA initiated informal

consultation in early 1994, and

completed formal consultation in April

2000. As a result of the consultation,

EPA modified some of the provisions in

the final rule.

As part of the consultation process,

EPA submitted to the Services a

Biological Evaluation for their review in

October of 1997. This evaluation found

that the proposed CTR was not likely to

jeopardize the continued existence of

any Federally listed species or result in

the destruction or adverse modification

of designated critical habitat. In April of

1998, the Services sent EPA a draft

Biological Opinion which tentatively

found that EPA’s proposed rule would

jeopardize the continued existence of

several Federally listed species and

result in the destruction or have adverse

effect on designated critical habitat.

After lengthy discussions with the

Services, EPA agreed to several changes

in the final rule and the Services in turn

issued a final Biological Opinion

finding that EPA’s action would not

likely jeopardize the continued

existence of any Federally listed species

or result in the destruction or adverse

modification of designated critical

habitat. EPA’s Biological Evaluation and

the Services’ final Biological Opinion

are contained in the administrative

record for today’s rule.

In order to ensure the continued

protection of Federally listed threatened

and endangered species and to protect

their critical habitat, EPA agreed to

reserve the aquatic life criteria for

mercury and the acute freshwater

aquatic life criterion for selenium. The

Services believe that EPA’s proposed

criteria are not sufficiently protective of

Federally listed species and should not

be promulgated. EPA agreed that it

would reevaluate these criteria in light

of the Services concerns before

promulgating them for the State of

California. Other commitments made by

EPA are described in a letter to the

Services dated December 16, 1999; this

letter is contained in the administrative

record for today’s rule.

N. Congressional Review Act

The Congressional Review Act, 5

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

Business Regulatory Enforcement

Fairness Act of 1996, generally provides

that before a rule may take effect, the

Agency promulgating the rule must

submit a rule report, which includes a

copy of the rule, to each House of the

Congress and to the Comptroller General

of the United States. EPA will submit a

report containing this rule and other

required information to the U.S. Senate,

the U.S. House of Representatives, and

the Comptroller General of the United

States prior to publication of the rule in

the Federal Register. A major rule

cannot take effect until 60 days after it

is published in the Federal Register.

This rule is not a major rule as defined

31710 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

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

effective May 18, 2000.

O. Executive Order 13084, Consultation

and Coordination With Indian Tribal

Governments

Under Executive Order 13084, EPA

may not issue a regulation that is not

required by statute, that significantly or

uniquely affects the communities of

Indian tribal governments, and that

imposes substantial direct compliance

costs on those communities, unless the

Federal government provides the funds

necessary to pay the direct compliance

costs incurred by the tribal

governments, or EPA consults with

those governments. If EPA complies by

consulting, Executive Order 13084

requires EPA to provide to the Office of

Management and Budget, in a separately

identified section of the preamble to the

rule, a description of the extent of EPA’s

prior consultation with representatives

of affected tribal governments, a

summary of the nature of their concerns,

and a statement supporting the need to

issue the regulation. In addition,

Executive Order 13084 requires EPA to

develop an effective process permitting

elected officials and other

representatives of Indian tribal

governments ‘‘to provide meaningful

and timely input in the development of

regulatory policies on matters that

significantly or uniquely affect their

communities.’’

Today’s rule does not significantly or

uniquely affect the communities of

Indian tribal governments nor does it

impose substantial direct compliance

cots on them. Today’s rule will only

address priority toxic pollutant water

quality criteria for the State of California

and does not apply to waters in Indian

country. Accordingly, the requirements

of section 3(b) of Executive Order 13084

do not apply to this rule.

P. National Technology Transfer and

Advancement Act

Section 12(d) of the National

Technology Transfer and Advancement

Act of 1995 (‘‘NTTAA’’), Public Law No.

104–113, section 12(d) (15 U.S.C. 272

note) directs EPA to use voluntary

consensus standards in its regulatory

activities unless to do so would be

inconsistent with applicable law or

otherwise impractical. Voluntary

consensus standards are technical

standards (e.g., materials specifications,

test methods, sampling procedures, and

business practices) that are developed or

adopted by voluntary consensus

standards bodies. The NTTAA directs

EPA to provide Congress, through OMB,

explanations when the Agency decides

not to use available and applicable

voluntary consensus standards.

This final rule does not involve

technical standards. Therefore, EPA did

not consider the use of any voluntary

consensus standards.

Q. Executive Order 13132 on

Federalism

Executive Order 13132, entitled

‘‘Federalism’’ (64 FR 43255, August 10,

1999), requires EPA to develop an

accountable process to ensure

‘‘meaningful and timely input by State

and local officials in the development of

regulatory policies that have federalism

implications.’’ ‘‘Policies that have

federalism implications’’ is defined in

the Executive Order to include

regulations that have ‘‘substantial direct

effects on the States, on the relationship

between the national government and

the States, or on the distribution of

power and responsibilities among the

various levels of government.’’

Under section 6 of Executive Order

13132, EPA may not issue a regulation

that has federalism implications, that

imposes substantial direct compliance

costs, and that is not required by statute,

unless the Federal government provides

the funds necessary to pay the direct

compliance costs incurred by State and

local governments, or EPA consults with

State and local officials early in the

process of developing the proposed

regulation. EPA also may not issue a

regulation that has federalism

implications and that preempts State

law, unless the Agency consults with

State and local officials early in the

process of developing the proposed

regulation.

This final rule does not have

federalism implications. It will not have

substantial direct effects on the States,

on the relationship between the national

government and the States, or on the

distribution of power and

responsibilities among the various

levels of government, as specified in

Executive Order 13132. The rule does

not affect the nature of the relationship

between EPA and States generally, for

the rule only applies to water bodies in

California. Further, the rule will not

substantially affect the relationship of

EPA and the State of California, or the

distribution of power or responsibilities

between EPA and the State. The rule

does not alter the State’s authority to

issue NPDES permits or the State’s

considerable discretion in implementing

these criteria. The rule simply

implements Clean Water Act section

303(c)(2)(B) requiring numeric ambient

water quality criteria for which EPA has

issued section 304(a) recommended

criteria in a manner that is consistent

with previous regulatory guidance that

the Agency has issued to implement

CWA section 303(c)(2)(B). Further, this

rule does not preclude the State from

adopting water quality standards that

meet the requirements of the CWA.

Thus, the requirements of section 6 of

the Executive Order do not apply to this

rule.

Although section 6 of Executive Order

13132 does not apply to this rule, EPA

did consult with State and local

government representatives in

developing this rule. EPA and the State

reached an agreement that to best utilize

its respective resources, EPA would

promulgate water quality criteria and

the State would concurrently work on a

plan to implement the criteria. Since the

proposal of this rule, EPA has kept State

officials fully informed of changes to the

proposal. EPA has continued to invite

comment from the State on these

changes. EPA believes that the final CTR

incorporates comments from State

officials and staff.

R. Executive Order 13045 on Protection

of Children From Environmental Health

Risks and Safety Risks

Executive Order 13045: ‘‘Protection of

Children from Environmental Health

Risks and Safety Risks’’ (62 FR 19885,

April 23, 1997) applies to any rule that:

(1) Is determined to be ‘‘economically

significant’’ as defined under Executive

Order 12866, and (2) concerns an

environmental health or safety risk that

EPA has reason to believe may have a

disproportionate effect on children. If

the regulatory action meets both criteria,

the Agency must evaluate the

environmental health or safety effects of

the planned rule on children, and

explain why the planned regulation is

preferable to other potentially effective

and reasonably feasible alternatives

considered by the Agency.

While this final rule is not subject to

the Executive Order because it is not

economically significant as defined in

Executive Order 12866, we nonetheless

have reason to believe that the

environmental health or safety risk

addressed by this action may have a

disproportionate effect on children. As

a matter of EPA policy, we therefore

have assessed the environmental health

or safety effects of ambient water quality

criteria on children. The results of this

assessment are contained in section F.3.,

Human Health Criteria.

List of Subjects in 40 CFR Part 131

Environmental protection, Indians—

lands, Intergovernmental relations,

Reporting and recordkeeping

requirements, Water pollution control.

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31711

Dated: April 27, 2000.

Carol Browner,

Administrator.

For the reasons set out in the

preamble, part 131 of chapter I of title

40 of the Code of Federal Regulations is

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 promulgates

criteria for priority toxic pollutants in

the State of 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 as

described in the following table:

BILLING CODE 6560–50–P

31712 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31713

31714 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31715

BILLING CODE 6560–50–C

31716 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

Footnotes to Table in Parargraph (b)(1):

a. Criteria 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. Criteria apply to California waters except

for those waters subject to objectives in

Tables III–2A and III–2B of the San Francisco

Regional Water Quality Control Board’s

(SFRWQCB) 1986 Basin Plan, that were

adopted by the SFRWQCB and the State

Water Resources Control Board, approved by

EPA, and which continue to apply.

c. Criteria are based on carcinogenicity of

10 (-6) risk.

d. Criteria Maximum Concentration (CMC)

equals the highest concentration of a

pollutant to which aquatic life can be

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. 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. 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)¥4.869). CCC =

exp(1.005(pH)¥5.134).

g. This criterion is based on 304(a) aquatic

life criterion issued in 1980, and was issued

in one of the following documents: Aldrin/

Dieldrin (EPA 440/5–80–019), Chlordane

(EPA 440/5–80–027), DDT (EPA 440/5–80–

038), Endosulfan (EPA 440/5–80–046),

Endrin (EPA 440/5–80–047), Heptachlor

(440/5–80–052), Hexachlorocyclohexane

(EPA 440/5–80–054), Silver (EPA 440/5–80–

071). The Minimum Data Requirements and

derivation procedures were different in the

1980 Guidelines than in the 1985 Guidelines.

For example, a ‘‘CMC’’ derived using the

1980 Guidelines was derived to be used as

an instantaneous maximum. If assessment is

to be done using an averaging period, the

values given should be divided by 2 to obtain

a value that is more comparable to a CMC

derived using the 1985 Guidelines.

h. These totals simply sum the criteria in

each column. For aquatic life, there are 23

priority toxic pollutants with some type of

freshwater or saltwater, acute or chronic

criteria. For human health, there are 92

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 the 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 x WER; CCC =

column B2 or C2 value x WER.

j. No criterion 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. The CWA 304(a) criterion for asbestos is

the MCL.

l. [Reserved]

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 in § 131.36(b)(1) and (2).

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’’), at § 131.36. 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. This

section does not apply instead of the NTR for

this criterion.

p. A criterion of 20 ug/l was promulgated

for specific waters in California in the NTR

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. This

section does not apply instead of the NTR for

this criterion. The State of California adopted

and EPA approved a site specific criterion for

the San Joaquin River, mouth of Merced to

Vernalis; therefore, this section does not

apply to these waters.

q. This criterion is expressed in the total

recoverable form. This criterion was

promulgated for specific waters in California

in the NTR 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. This

criterion does not apply instead of the NTR

for these waters. This criterion applies to

additional waters of the United States in the

State of California pursuant to 40 CFR

131.38(c). 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. 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 Sacramento-San Joaquin Delta. This

section does not apply instead of the NTR for

these criteria.

s. These criteria were promulgated for

specific waters in California in the NTR. 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. This section does

not apply instead of the NTR for these

criteria.

t. These criteria were promulgated for

specific waters in California in the NTR. 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. This section does not apply

instead of the NTR 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

the sum of this set of seven aroclors.

v. This criterion applies to total PCBs, e.g.,

the sum of all congener or isomer or homolog

or aroclor 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.

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 criteria do not

apply to these waters.

General Notes to Table in Paragraph (b)(1)

1. The table in this paragraph (b)(1) lists all

of EPA’s priority toxic pollutants whether or

not criteria guidance are available. Blank

spaces indicate the absence of national

section 304(a) criteria guidance. Because of

variations in chemical nomenclature systems,

this listing of toxic pollutants does not

duplicate the listing in Appendix A to 40

CFR Part 423–126 Priority Pollutants. 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: zinc, 3-

methyl-4-chlorophenol.

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31717

3. Freshwater and saltwater aquatic life

criteria apply as specified in paragraph (c)(3)

of this section.

(2) Factors for Calculating Metals

Criteria. Final CMC and CCC values

should be rounded to two significant

figures.

(i) CMC = WER × (Acute Conversion

Factor) × (exp{mA[1n

(hardness)]+bA})

(ii) CCC = WER × (Acute Conversion

Factor) × (exp{mC[1n

(hardness)]+bC})

(iii) Table 1 to paragraph (b)(2) of this

section:

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 to Table 1: The term ‘‘exp’’ represents the base e exponential function.

(iv) Table 2 to paragraph (b)(2) of this section:

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 b 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 b 0.791 0.951 0.951

Mercury .................................................................................................. ............................ .......................... .......................... ..........................

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

Selenium ................................................................................................ ............................ (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 to Table 2 of Paragraph (b)(2):

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 in freshwater 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 equations in table 3 to paragraph (b)(2) of this section. c Bioaccumulative compound and inappropriate to adjust to percent dissolved.

d EPA has not published an aquatic life criterion value.

Note to Table 2 of Paragraph (b)(2): 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 Water

Resource Center, USEPA, Mailcode RC4100,

M Street SW, Washington, DC, 20460 and the

note to § 131.36(b)(1).

(v) Table 3 to paragraph (b)(2) of this

section:

Acute Chronic

Cadmium .............................. CF=1.136672—[(ln {hardness}) (0.041838)] .................. CF = 1.101672—[(ln {hardness})(0.041838)]

Lead ..................................... CF=1.46203—[(ln {hardness})(0.145712)] ..................... CF = 1.46203—[(ln {hardness})(0.145712)]

(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 to the table in

paragraph (b)(1) 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 flows in Table 4 to paragraph

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

rivers.

(iii) Table 4 to paragraph (c)(2) of this

section:

31718 Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations

Criteria Design flow

Aquatic Life Acute

Criteria (CMC).

1 Q 10 or 1 B 3

Aquatic Life Chronic

Criteria (CCC).

7 Q 10 or 4 B 3

Human Health Criteria.Harmonic Mean Flow

Note to Table 4 of Paragraph (c)(2): 1. 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

not to be exceeded more than once every

three years on the average.

2. 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.

3. 1 Q 10 is the lowest one day flow with

an average recurrence frequency of once in

10 years determined hydrologically.

4. 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).

5. 7 Q 10 is the lowest average 7

consecutive day low flow with an average

recurrence frequency of once in 10 years

determined hydrologically.

6. 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).

(iv) 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) of this section

apply at all flows.

(v) If the CMC short-term averaging

period, the CCC four-day averaging

period, or once in three-year frequency

is inappropriate for a criterion or the

site to which a criterion applies, the

State may apply to EPA for approval of

an alternative averaging period,

frequency, and related design flow. The

State must submit to EPA the bases for

any alternative averaging period,

frequency, and related design flow.

Before approving any change, EPA will

publish for public comment, a

document proposing the change.

(3) The freshwater and saltwater

aquatic life criteria in the matrix in

paragraph (b)(1) 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 to the table

in paragraph (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. Before

approving any change, EPA will publish

for public comment a document

proposing the change.

(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 design flows

and mixing zones.

(iii) The criteria for metals

(compounds #1—#13 in the table in

paragraph (b)(1) 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

to the table 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’’) 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 identified in the

Basin Plans. More particularly, these

criteria apply to waters identified in the

Basin Plan chapters designating

beneficial uses for waters within the

region. 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 criteria from the table in

paragraph (b)(1) of this section apply to

the water and use classifications defined

in paragraph (d)(1) of this section as

follows:

Federal Register / Vol. 65, No. 97 / Thursday, May 18, 2000 / Rules and Regulations 31719

Water and use classification Applicable criteria

(i) 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.

(A) Columns B1 and B2—all pollutants

(B) Columns C1 and C2—all pollutants

(C) Column D1—all pollutants

(ii) 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.

(A) Columns B1 and B2—all pollutants

(B) Columns C1 and C2—all pollutants

(C) Column D2—all pollutants

(3) Nothing in this section is intended

to apply instead of specific criteria,

including specific criteria for the San

Francisco Bay estuary, promulgated for

California in the National Toxics Rule at

§ 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

May 18, 2000 to a new discharger

contains a WQBEL based on water

quality criteria set forth in paragraph (b)

of this 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

commences after May 18, 2000.

(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

paragraph (b) of 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) The provisions in this paragraph

(e), Schedules of compliance, shall

expire on May 18, 2005.

[FR Doc. 00–11106 Filed 5–17–00; 8:45 am]

BILLING CODE 6560–50–P