42554 Federal Register / Vol. 62, No. 152 / Thursday, August 7, 1997 / Notices

Methodology ends at page D–6, which is

a placeholder for a table which was

never developed in final form for

inclusion in Appendix D. EPA is

assembling some of the information that

was intended for inclusion in that table

and will make it available in the docket

by August 7, 1997.

Additionally, EPA is developing

materials to assist reviewers in

identifying the underlying sources of

data used as the basis for scoring

chemicals, beyond the explanations

already provided in Appendices B and

C of the draft Waste Minimization

Prioritization Tool (Beta Test Version

1.0): User’s Guide and System

Documentation (EPA530–R–97–019).

EPA intends to place these additional

materials in the docket by August 7,

1997. EPA determined that it needed to

extend the comment period by a total of

60 days to allow commenters to review

these additional materials and to

provide an adequate opportunity for

public participation in the review of this

waste minimization prioritization

software and accompanying documents.

Dated: July 31, 1997.

Matthew Hale,

Acting Director, Office of Solid Waste.

[FR Doc. 97–20822 Filed 8–6–97; 8:45 am]

BILLING CODE 6560–50–P

ENVIRONMENTAL PROTECTION

AGENCY

[OW–FRL–5872–5]

Water Quality Criteria; Ambient Water

Quality Criteria

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of Ambient Water

Quality Criteria Document for

Tributyltin (TBT) and Request for

Comments.

SUMMARY: The Environmental Protection

Agency (EPA) announces the

availability for public comment of an

ambient water quality criteria document

for tributyltin (TBT). This document

contains ambient water quality criteria

for the protection of aquatic organisms

and their uses. These criteria are

guidance to States and others, and in

themselves have no binding legal effect.

When published in final form, these

criteria may form the basis for

enforceable State water quality

standards. These TBT criteria are

published pursuant to Section 304(a)(1)

of the Clean Water Act.

DATES: Written comments should be

submitted to the person listed directly

below by October 6, 1997.

ADDRESSES: This notice contains a

summary of the criteria document for

tributyltin (TBT). Copies of the

complete document may be obtained

from: U.S. Environmental Protection

Agency , National Center for

Environmental Publications and

Information, 11029 Kenwood Road,

Cincinnati, Ohio 45242, phone (513)

489–8190 fax (513) 489–8695.

FOR FUTHER INFORMATION CONTACT:

Comments should be sent to: Dr. Frank

Gostomski, Health and Ecological

Criteria Division (4304), Office of

Science and Technology, Office of

Water, U.S. Environmental Protection

Agency, 401 M Street SW, Washington,

DC 20460.

SUPPLEMENTARY INFORMATION:

Background

Section 304 (a) (1) of the Clean Water

Act [33 U.S.C. 1314 (a) (1)] requires EPA

to publish and periodically update

ambient water quality criteria. These

criteria are to reflect the latest scientific

knowledge on the identifiable effects of

pollutants on public health and welfare,

aquatic life and recreation. When

published in final form, EPA water

quality criteria may form the basis for

enforceable State water quality

standards.

Criteria Document

EPA previously issued an ambient

water quality criteria document for TBT

for public comment on June 1, 1989 [54

FR 23529]. EPA also issued a notice of

availability of additional toxicity data

for TBT on October 25, 1989 [54 FR

43482]. Today’s ambient water quality

criteria document for TBT was

developed by EPA after consideration of

public comment on the 1989 draft

criteria and an updated literature search

that EPA conducted in January, 1997.

EPA intends to issue a final TBT

ambient water quality criteria document

after consideration of public comment.

Dated: August 1, 1997.

Robert Perciasepe,

Assistant Administrator for Water.

Appendix A—Summary of Ambient Water

Quality Criteria for TBT

Freshwater Aquatic Life

The procedures described in the

‘‘Guidelines for Deriving Numerical National

Water Quality Criteria for the Protection of

Aquatic Organisms and Their Uses’’ indicate

that, except possibly where a locally

important species is very sensitive,

freshwater aquatic life and their uses should

not be affected unacceptably if the four-day

average concentration of tributyltin does not

exceed 0.063 μg/L more than once every

three years on the average and if the one-hour

average concentration does not exceed 0.46

μg/L more than once every three years on the

average.

Saltwater Aquatic Life

The procedures described in the

‘‘Guidelines for Deriving Numerical National

Water Quality Criteria for the Protection of

Aquatic Organisms and Their Uses’’ indicate

that, except where a locally important

species is very sensitive, saltwater organisms

and their uses should not be affected

unacceptably if the four-day average

concentration of tributyltin does not exceed

0.010 μg/L more than once every three years

on the average and if the one-hour average

concentration does not exceed 0.37 μg/L

more than once every three years on the

average.

Implementation

As discussed in the Water Quality

Standards Regulation (40 CFR Part 131; 48

FR 51400), a water quality criterion for

aquatic life has regulatory effect only after it

has been adopted in State water quality

standards. Such a criterion for a pollutant is

to be set at a level protective of a particular

designated use. With the approval of EPA,

States designate one or more uses for each

body of water or segment thereof and adopt

criteria that are protective of the use[s]. In

each standard, a State may adopt the national

recommended criterion, if one exists, or if

adequately justified, a site-specific criterion.

Site-specific criteria may include not only

site-specific criterion concentrations, but also

site-specific, and possibly pollutant-specific,

durations of averaging periods and

frequencies of allowed excursions. The

averaging periods of ‘‘one hour’’ and ‘‘four

days’’ were selected by EPA on the basis of

data concerning how rapidly some aquatic

species react to increases in the

concentrations of some pollutants.

It is EPA’s best scientific judgment that

aquatic ecosystems should not be exposed to

contaminants in excess of the criterion more

often than once every three years. However,

various species and ecosystems react and

recover at greatly differing rates. Therefore, if

adequate justification is provided, sitespecific and/or pollutant-specific

concentrations, durations, and frequencies

may be higher or lower than those given in

national water quality criteria for aquatic life.

Use of criteria, which have been adopted in

state water quality standards, for developing

water quality-based permit limits and for

designing waste treatment facilities requires

selection of an appropriate wasteload

allocation model. Although dynamic models

are preferred for the application of these

criteria, limited data or other considerations

might require the use of a steady-state model.

Guidance on mixing zones and the design of

monitoring programs is also available

through EPA.

[FR Doc. 97–20975 Filed 8–6–97; 8:45 am]

BILLING CODE 6560–50–P