Document ID: EPA-HQ-OW-2003-0079-0075
Agency: epa
Document Type: Notice
Title: Aquatic Life Ambient Freshwater Quality Criteria--Copper 2007 Revision
Posted Date: 2007-02-22T05:00Z

[Federal Register: February 22, 2007 (Volume 72, Number 35)]
[Notices]               
[Page 7983-7985]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22fe07-47]                         

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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OW-2003-0079; FRL-OW-8280-2]

 
Aquatic Life Ambient Freshwater Quality Criteria--Copper 2007 
Revision

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Availability.

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SUMMARY: The Environmental Protection Agency (EPA) announces the 
availability of the 2007 revised recommended aquatic life ambient 
freshwater quality criteria for copper. The Clean Water Act (CWA) 
requires

[[Page 7984]]

EPA to develop and publish, and from time to time revise, criteria for 
water accurately reflecting the latest scientific knowledge. These 
criteria provide EPA's recommendations to states and authorized tribes 
as they establish their water quality standards as state or tribal law 
or regulation. An EPA water quality criterion does not substitute for 
requirements of the CWA or EPA regulations, nor is an EPA criteria 
recommendation a regulation. It does not impose legally binding 
requirements on the EPA, states, authorized tribes or the regulated 
community. State and tribal decision makers have discretion to adopt 
approaches that differ from EPA's water quality criteria 
recommendations on a case-by-case basis. Today, the Agency is making a 
revised recommendation about water quality criteria for copper.

ADDRESSES: Copies of the criteria document entitled, Aquatic Life 
Ambient Freshwater Quality Criteria--Copper 2007 Revision (EPA-822-R-
07-001) may be obtained from EPA's Water Resource Center by phone at 
(202) 566-1729, or by e-mail to center.water.resource@epa.gov or by 
conventional mail to: U.S. EPA Water Resource Center, 4101T, 1200 
Pennsylvania Avenue, NW., Washington, DC 20460. You can also download 
the criteria document and the fact sheet from EPA's Web site at http://www.epa.gov/waterscience/criteria/copper/index.htm
.

FOR FURTHER INFORMATION CONTACT: Dr. Luis Cruz, Health and Ecological 
Criteria Division (4304T), U.S. EPA, 1200 Pennsylvania Avenue, NW., 
Washington, DC 20460; (202) 566-1095; cruz.luis@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Interested Entities

    Entities potentially interested in today's notice are those that 
produce, use, or regulate copper. Categories and entities interested in 
today's notice include:

------------------------------------------------------------------------
                                               Examples of interested
                 Category                             entities
------------------------------------------------------------------------
State/Local/Tribal Government.............  States, Tribes and
                                             Municipalities.
Industry..................................  Mining, fabricated metal
                                             products, electric
                                             equipment, leather
                                             products.
------------------------------------------------------------------------

    This table is not exhaustive, but rather provides a guide for 
readers regarding the entities likely to be interested in this notice. 
Other types of entities not listed in the table could also be 
interested.

B. How Can I Get Copies of This Document and Other Related Information?

1. Docket
    EPA established an official public docket for the initial draft 
criteria document and scientific views received under Docket ID No. 
EPA-HQ-OW-2003-0079. The official public docket will also consist of 
the 2007 revised criteria document and scientific views received. 
Although a part of the official docket, the public docket does not 
include Confidential Business Information (CBI) or other information 
whose disclosure is restricted by statute. Publicly available docket 
materials are available either electronically through http://www.regulations.gov
, or in hard copy at the Water Docket in the EPA 

Docket Center, (EPA/DC) EPA West, Room B102, 1301 Constitution Ave., 
NW., Washington, DC. The EPA Docket Center Public Reading Room is open 
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal 
holidays. The telephone number for the Public Reading Room is (202) 
566-1744, and the telephone number for the Water Docket is (202) 566-
2426. To view these documents and materials, please call ahead to 
schedule an appointment. Every user is entitled to copy 266 pages per 
day before incurring a charge. The Docket may charge 15 cents a page 
for each page over the 266-page limit plus an administrative fee of 
$25.00.
2. Electronic Access
    You may access this Federal Register document electronically 
through the EPA's Internet listings under the Federal Register at: 
http://www.epa.gov/fedrgstr/.

II. Background and Today's Notice of Availability

A. What Are EPA Recommended Ambient Water Quality Criteria?

    An EPA recommended ambient water quality criterion is a description 
of the amount of a pollutant or other measurable substance in water 
that, when met, will protect aquatic life and/or human health. Water 
quality criteria are based on the factors specified in section 304(a) 
of the Clean Water Act, including the kind and extent of effects of the 
pollutant on human health and aquatic organisms. Section 304(a) of the 
Clean Water Act (CWA or the Act) requires EPA to develop and publish 
and, from time to time, revise, recommended ambient water quality 
criteria to accurately reflect the latest scientific knowledge. An EPA 
water criterion does not substitute for requirements of the CWA or EPA 
regulations, nor is an EPA criteria recommendation a regulation. It 
does not impose legally binding requirements on EPA, states, authorized 
tribes or the regulated community. State and tribal decision makers 
have discretion to adopt approaches that differ from EPA's water 
quality criteria recommendations on a case-by-case basis.
    Ambient water quality criteria developed under section 304(a) 
provide guidance to states and tribes in adopting water quality 
criteria into their water quality standards under section 303(c) of the 
CWA. Once adopted by a state or tribe, the water quality standards are 
then a basis for developing regulatory controls on the discharge or 
release of pollutants and other alterations of water quality. EPA's 
section 304(a) criteria also provide a scientific basis for EPA to 
develop any necessary federal water quality regulations under section 
303(c) of the CWA.

B. What Is the Relationship Between the Water Quality Criteria and Your 
State or Tribal Water Quality Standards?

    The revised recommended criteria in today's notice are based on the 
factors specified in section 304(a) of the Clean Water Act, including 
the kind and extent of effects of the pollutant on human health and 
aquatic organisms. EPA's recommended criteria are used by the states 
and tribes in developing their regulatory criteria under section 303(c) 
of the CWA. Under the Clean Water Act, regulatory water quality 
criteria must protect the designated use, independent of the economic 
and technical feasibility of meeting the criteria. Economic and 
technical feasibility factors are considered by states and tribes when 
they adopt designated uses into their water quality standards under 
section 303(c) of the Act and when states, tribes, and EPA consider 
variance requests. Moreover, states and tribes may also consider 
alternative scientifically defensible approaches to adopting criteria 
into their water quality standards.
    Section 303(c)(1) of the CWA requires states and authorized tribes 
to review and modify, if appropriate, their water quality standards at 
least once every three years. Water quality standards consist of 
designated uses, water quality criteria to protect those uses, a policy 
for antidegradation, and general policies for application and 
implementation. States and authorized tribes must adopt water quality 
criteria that protect designated uses. Protective criteria, based on a 
sound scientific rationale, contain appropriate factors to protect the 
designated uses. Criteria may be

[[Page 7985]]

either narrative or numeric. States and authorized tribes have four 
options when adopting water quality criteria for parameters for which 
EPA has published section 304(a) criteria. They may: (1) Establish 
numerical values based on recommended CWA section 304(a) criteria; (2) 
Establish numerical values based on CWA section 304(a) criteria 
modified to reflect site-specific conditions; (3) Establish numerical 
values based on other scientifically defensible methods; or (4) 
Establish narrative criteria or criteria based upon biomonitoring 
methods where numerical criteria cannot be determined or to supplement 
numerical criteria. See 40 CFR 131.11(b).
    Pursuant to 40 CFR 131.21, water quality criteria that states and 
authorized tribes adopted and submitted to EPA before May 30, 2000, are 
in effect for CWA purposes. The criteria remain in effect unless and 
until EPA promulgates federal regulations that supersede them or EPA 
approves a revised state criteria. See, e.g., the National Toxics Rule, 
40 CFR 131.36; Water Quality Standards for Idaho, 40 CFR 131.33. New or 
revised water quality criteria that states and authorized tribes 
adopted into law or regulation and submit to EPA on or after May 30, 
2000, are in effect for CWA purposes only after EPA approves them.

C. What Is the History of Today's Revised Criteria?

    EPA notified the public of its intentions to revise the recommended 
aquatic life criteria for copper in the Federal Register on October 29, 
1999 (63 FR 58406). On December 31, 2003 EPA published a Federal 
Register Notice announcing the availability of the document Notice of 
Availability of Draft Aquatic Life Criteria Document for Copper and 
Request for Scientific Views (68 FR 75552). The initial draft criteria 
document contained recommendations for both freshwater and saltwater 
criteria derivations; however, EPA has since determined that the biotic 
ligand model requires further development before it is suitable for use 
to evaluate saltwater data. On March 9, 2004 EPA published a Federal 
Register Notice (69 FR 11012) announcing the reopening of the period to 
submit scientific views in response to requests from the public. 
Comments received were supportive of using the BLM for deriving 
freshwater criteria for copper. Issues related to criteria derivation 
process were answered, as well as corrections in matters of scientific 
relevance related to the applicability of the BLM.

D. What Is Copper?

    Copper is an abundant trace element found in the earth's crust and 
is a naturally occurring element that is generally present in surface 
waters. Copper is a micronutrient at low concentrations and recognized 
as essential to virtually all plants and animals. Historically, 
elevated levels of copper have been linked to adverse effects on 
aquatic organisms and concerns have prompted its inclusion as a 
priority pollutant. Currently, there are 629 rivers and streams listed 
as impaired for copper and 5 for contaminated sediments due to copper.

E. What Is New About the Revised Criteria?

    The aquatic life criteria document titled, ``Aquatic Life Ambient 
Freshwater Quality Criteria--Copper 2007 Revision'' (EPA-822-R-07-001), 
contains revised recommendations for freshwater aquatic life criteria 
for copper. These revised criteria recommendations are based in part on 
new data that have become available since EPA's last comprehensive 
criteria updates for copper, ``Ambient Water Quality Criteria for 
Copper--1984'' (EPA-440/5-84-031). EPA derived the freshwater criteria 
recommendations presented in this draft document based on the 
principles set forth in EPA's 1985 Guidelines for Deriving Numerical 
National Aquatic Life Criteria for Protection of Aquatic Organisms and 
Their Uses. In addition to incorporating new data, the freshwater 
criterion maximum concentration (CMC or ''acute criterion'') also 
relies on a new scientific model, the biotic ligand model (BLM), in the 
criteria derivation procedures. The freshwater criterion continuous 
concentration (CCC or ``chronic criterion'') is based on a BLM derived 
acute value divided by a final acute-chronic ratio. Where used, the 
application of the BLM will replace the need for site-specific 
modifications, such as Water Effect Ratio, to account for site-specific 
chemistry influences on metal toxicity.

F. How Do BLM-Derived Criteria Differ From Hardness-Dependent Criteria?

    The biotic ligand model is a metal bioavailability model based on 
recent information about the chemical behavior and physiological 
effects of metals in aquatic environments. Earlier freshwater aquatic 
life criteria for copper published by the Agency were based on 
empirical relationships of toxicity to water hardness. That is, a 
relationship was established linking the criteria concentrations with 
water hardness. These hardness-dependent criteria, however, represented 
combined effects of different water quality variables (such as pH and 
alkalinity) correlated with hardness. Unlike the empirically derived 
hardness-dependent criteria, the BLM explicitly accounts for individual 
water quality variables and addresses variables that EPA had not 
previously factored into the hardness relationship. Where the previous 
freshwater aquatic life criteria were hardness-dependent, these revised 
criteria are dependent on a number of water quality parameters (e.g., 
calcium, magnesium, dissolved organic carbon) described in the 
document. BLM-based criteria can be more stringent than the current 
hardness-based copper criteria and in certain cases the current 
hardness-based copper criteria may be overly stringent for particular 
water bodies.
    More information on the development and application of the biotic 
ligand model is available in the criteria document as well as in The 
Biotic Ligand Model: Technical Support Document for Its Application to 
the Evaluation of Water Quality Criteria for Copper (EPA 822-R-03-027) 
and Integrated Approach to Assessing the Bioavailability and Toxicity 
of Metals in Surface Waters and Sediments (EPA-822-E-99-001).

G. What Are the New Revised Criteria for Copper?

    The available toxicity data, when evaluated using the procedures 
described in the ``Guidelines for Deriving Numerical National Water 
Quality Criteria for the Protection of Aquatic Organisms and Their 
Uses'' indicate that freshwater aquatic life should be protected if the 
24-hour average and four-day average concentrations do not respectively 
exceed the acute and chronic criteria concentrations calculated by the 
Biotic Ligand Model.
    A return interval of 3 years between exceedances of the criterion 
continues to be EPA's general recommendation. However, the resilience 
of ecosystems and their ability to recover differ greatly. Therefore, 
scientific derivation of alternative frequencies for exceeding criteria 
may be appropriate.

    Dated: February 15, 2007.
Ephraim King,
Director, Office of Science and Technology.
 [FR Doc. E7-3007 Filed 2-21-07; 8:45 am]

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