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GLIN==> Framework for toxic equivalents for ecological risk



This will be of interest to those dealing with Great Lakes
ecological risk and the chlorinated dioxin/furan problem.

[Federal Register: July 30, 2003 (Volume 68, Number 146)]
[Notices]
[Page 44784-44785]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30jy03-57]

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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 <A HREF="" href="" eudora="autourl">http://cfpub.
epa.gov/ncea/raf/recordisplay.cfm?deid=55669</A>. 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 <A HREF="" href="" eudora="autourl">http://www.epa.gov/edocket</A> (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: <A HREF="">
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 <A HREF="" href="" eudora="autourl">http://www.epa.gov/edocket</A> 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]
BILLING CODE 6560-50-P


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