[Federal Register Volume 68, Number 146 (Wednesday, July 30, 2003)]
[Notices]
[Pages 44784-44785]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-19351]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-7537-7]


Framework for Application of the Toxicity Equivalence Methodology 
for Polychlorinated Dioxins, Furans, and Biphenyls in Ecological Risk 
Assessment (External Review Draft); Notice of Availability

AGENCY: Environmental Protection Agency.

ACTION: Notice of availability and opportunity for public comment.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing a 
60-day public comment period for the draft document titled Framework 
for Application of the Toxicity Equivalence Methodology for 
Polychlorinated Dioxins, Furans, and Biphenyls in Ecological Risk 
Assessment. The document is intended to describe a methodology for 
assessing ecological risks associated with complex mixtures of dioxins, 
furans, and dioxin-like PCBs in the environment. EPA will consider the 
public comments in revising the document.

DATES: Comments must be received by September 29, 2003.

ADDRESSES: The draft is available via the Internet at http://cfpub.epa.gov/ncea/raf/recordisplay.cfm?deid=55669. Comments may be 
submitted electronically, by mail, or in person, as described in the 
instructions under Supplementary Information. Comments may be viewed at 
EPA Dockets at http://www.epa.gov/edocket (under Docket ID No. ORD-
2003-0002).

FOR FURTHER INFORMATION CONTACT: Marilyn Brower, U.S. EPA, ORD National 
Center for Environmental Assessment, Risk Assessment Forum Staff 
(8601D), 1200 Pennsylvania Ave. NW., Washington, DC 20460; telephone: 
202-564-3363; fax: 202-565-0062; e-mail: [email protected].

SUPPLEMENTARY INFORMATION: 

I. Submission of Comments

    You may submit comments electronically, by mail, or through hand 
delivery/courier. To ensure proper receipt by EPA, identify the 
appropriate docket identification number (ORD-2003-0002) in the subject 
line on the first page of your comment. Please note that all comments 
received in response to this notice will be placed in a public record. 
For that reason, comments should not contain personal information (such 
as medical data or home address), Confidential Business Information, or 
information protected by copyright.

A. Electronically to EPA Dockets

    Your use of EPA's electronic public docket (EPA Dockets) to submit 
comments is EPA's preferred method for receiving comments. Go directly 
to EPA Dockets at http://www.epa.gov/edocket and follow the online 
instructions for submitting comments. Once in the system, select 
``search,'' and then key in Docket ID No. ORD-2003-0002. The system is 
an ``anonymous access'' system, which means EPA will not know your 
identity, e-mail address, or other contact information unless you 
provide it. EPA recommends that you include your name and contact 
information in the body of your comment to ensure that you can be 
identified as the submitter of the comment and to allow EPA to contact 
you in case EPA cannot read your comment due to technical difficulties 
or needs further information on the substance of your comment.

B. By Mail

    Comments may be sent to: Office of Environmental Information 
Docket, Environmental Protection Agency, Mailcode: 28220T, 1200 
Pennsylvania Ave. NW, Washington, DC 20460, Attention Docket ID No. 
ORD-2003-0002.

C. By Hand Delivery or Courier

    Deliver your comments to: Office of Environmental Information 
Docket, EPA West, Room B102, 1301 Constitution Ave. NW, Washington, DC, 
Attention Docket ID No. ORD-2003-0002. Such deliveries are only 
accepted during the Docket's normal hours of operation from 8:30 a.m. 
to 4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the docket is 202-566-1752.

II. Background

    Polychlorinated dioxins (PCDDs), furans (PCDFs), and biphenyls 
(PCBs) commonly occur as complex mixtures in the environment. For more 
than a decade, EPA and other organizations have estimated the combined 
risks that such mixtures pose to human health using a method known as 
the toxicity equivalence methodology. The methodology is based on 
findings that certain PCDDs, PCDFs, and PCBs share a common mechanism 
of action for their effects but differ in potency. The methodology uses 
potency factors (such as Toxicity Equivalence Factors, or TEFs) 
assigned to each chemical in the mixture as a way of integrating the 
risks from the entire mixture. Application in ecological risk 
assessments has proceeded more slowly than in human health risk 
assessment, in part because of the variety of species from different 
taxonomic classes (e.g., fish, birds, and mammals) to be considered.
    As both data and experience with the methodology have accumulated, 
however, experts have concluded that the toxicity equivalence 
methodology can strengthen assessments of ecological risks. At a World 
Health Organization consultation in 1997, international consensus TEFs 
for PCDDs, PCDFs, and PCBs were reviewed and the toxicity equivalence 
methodology expanded to include class-specific TEFs for mammals, birds 
and fish. In 1998, EPA and the U.S. Department of Interior sponsored a 
workshop that recommended the development of further guidance on 
application of the toxicity equivalence methodology. This draft 
framework has been developed in direct response to that workshop 
recommendation by a technical panel under EPA's Risk Assessment Forum.
    Organized in accordance with EPA's Guidelines for Ecological Risk 
Assessment (63 FR 26846), this framework is intended to assist EPA 
scientists in using the methodology, as well as to inform EPA decision 
makers, other agencies, and the public about this methodology. It 
provides ecological risk assessors with an understanding of the 
uncertainties associated with the application of the methodology in 
general and with situation-specific decisions made in applying the

[[Page 44785]]

methodology within their risk assessments. The draft framework also 
discusses several potential advantages of the toxicity equivalence 
methodology compared with alternative methods for estimating risks from 
mixtures of dioxin-like chemicals.
    The document is undergoing peer review concurrent with the public 
comment period described in this notice. This framework is not a 
regulation nor is it intended to substitute for federal regulations. It 
does not establish any substantive ``rules'' under the Administrative 
Procedure Act or any other law and will have no binding effect on EPA 
or any regulated entity.

    Dated: July 23, 2003.
Peter W. Preuss,
Director, National Center for Environmental Assessment.
[FR Doc. 03-19351 Filed 7-29-03; 8:45 am]
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