[Federal Register Volume 76, Number 4 (Thursday, January 6, 2011)]
[Notices]
[Page 787]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-20]


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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-ORD-2009-0605; FRL-9248-4]


Notice of Availability of the Recommended Toxicity Equivalence 
Factors (TEFs) for Human Health Risk Assessments of 2,3,7,8-
Tetrachlorodibenzo-p-dioxin and Dioxin-Like Compounds

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of document availability.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing 
the availability of the final ``Recommended Toxicity Equivalence 
Factors (TEFs) for Human Health Risk Assessments of 2,3,7,8-
Tetrachlorodibenzo-p-dioxin and Dioxin-Like Compounds'' (EPA/100/R-10/
005). The purpose of this document is to assist EPA scientists in using 
the toxicity equivalence methodology to assess health risks from 
dioxins and dioxin-like compounds, as well as inform EPA decision 
makers, other agencies, and the public about this methodology. This 
guidance document summarizes the toxicity equivalence methodology, 
provides background information and assumptions on how the methodology 
has evolved, and recommends an approach for health risk assessors to 
use to apply the methodology. EPA's Risk Assessment Forum (RAF) oversaw 
the development of this document. Input was obtained from scientists 
throughout the Agency, from interested members of the public, and from 
external experts from a range of scientific disciplines via a 
contractor-led peer review.

ADDRESSES: The final document is available electronically through the 
EPA Office of the Science Advisor's Web site at: http://www.epa.gov/osa/raf/hhtefguidance/. A limited number of paper copies will be 
available from EPA's National Service Center for Environmental 
Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 45242; telephone 
number: 1-800-490-9198 or 513-489-8190; facsimile number: 301-604-3408; 
e-mail: lmit.com">NSCEP@bps-lmit.com. Please provide your name, mailing address, 
and title of the requested publication.

FOR FURTHER INFORMATION CONTACT: Julie Fitzpatrick, Risk Assessment 
Forum Staff, Mail Code 8105R, Environmental Protection Agency, 1200 
Pennsylvania Avenue, NW., Washington, DC 20460; telephone number: (202) 
564-4212; facsimile number: (202) 564-2070; e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: Dioxin and dioxin-like compounds (DLCs), 
including polychlorinated dibenzo-dioxins (PCDDs), polychlorinated 
dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs), are 
structurally and toxicologically related halogenated dicyclic aromatic 
hydrocarbons. Dioxins and DLCs are released into the environment from 
several industrial sources, including chemical manufacturing, 
combustion, and metal processing. There is global contamination of air, 
soil and water with trace levels of these compounds. Typically, dioxins 
and DLCs occur in the environment as chemical mixtures. Dioxins and 
DLCs do not readily degrade; therefore, levels persist in the 
environment, build up in the food chain, and accumulate in the tissues 
of animals. Human exposures to these compounds occur primarily through 
eating contaminated foods. The health effects from exposures to dioxins 
and DLCs have been documented extensively in toxicological and 
epidemiological studies.
    Risk assessments have relied on the dioxin toxicity equivalence 
factors (TEFs) approach. Various stakeholders, inside and outside the 
Agency, have called for a more comprehensive characterization of risks. 
Therefore, EPA's RAF identified a need to examine the current 
recommended approach for application of the toxicity equivalence 
methodology in human health risk assessments. An RAF Technical Panel 
developed the draft guidance document, ``Recommended Toxicity 
Equivalence Factors (TEFs) for Human Health Risk Assessments of 
2,3,7,8-Tetrachlorodibenzo-p-dioxin and Dioxin-Like Compounds,'' to 
assist EPA scientists in using this methodology to assess health risks 
from dioxins and dioxin-like compounds, and inform EPA decision makers, 
other agencies, and the public about this methodology.
    An external expert peer review was conducted by both letter and an 
open, public teleconference in October 2009. The peer review panel was 
provided with the public comments received in the official public 
docket for this activity under docket ID number EPA-HQ-ORD-2009-0605. 
The peer review panel also had the opportunity to hear public comments 
provided during the peer review teleconference. In preparing the final 
document, EPA considered the public comments submitted to EPA's docket 
during the public comment period and during the public teleconference, 
and the recommendations from the external peer reviewers provided in 
the peer review report and during the public teleconference.
    EPA is currently addressing several issues related to dioxins and 
dioxin-like chemicals in the environment. More information on these 
activities is located at: http://www.epa.gov/dioxin/scienceplan/.

    Dated: December 22, 2010.
Paul T. Anastas,
EPA Science Advisor.
[FR Doc. 2011-20 Filed 1-5-11; 8:45 am]
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