Notice of Peer-Review Teleconference for the External Peer Review Draft of Recommended Toxicity Equivalency Factors (TEFs) for Human Health Risk Assessments of Dioxin and Dioxin-Like Compounds

Summary:

EPA is announcing that Versar, Inc., an EPA contractor for external scientific peer review, plans to convene an independent panel of experts and organize and conduct an external peer review meeting to review the draft document titled, “Recommended Toxicity Equivalency Factors (TEFs) for Human Health Risk Assessments of Dioxin and Dioxin-Like Compounds.” The peer review meeting is planned to take place by teleconference on October 22, 2009. On September 2, 2009, EPA announced a 30-day public comment period for the draft document (74 FR 45437). The draft document was prepared by the Agency's Risk Assessment Forum.

The public comment period and the external peer review are separate processes that provide opportunities for all interested parties to comment on the document. In addition to considering public comments that were submitted to the EPA docket by the closing date of October 2, 2009, in accordance with the September 2, 2009 announcement of a public comment period, the public can provide comments for the external peer reviewers' consideration through the public teleconference on October 22, 2009.

EPA is releasing this draft document solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. This document has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency policy or determination.

The public will be given an opportunity to observe and provide oral comments at this teleconference by registering with the point of contact below (see How Can I Request to Participate in this Meeting?). The draft document is available through the EPA docket at http://www.regulations.gov under Docket ID No. EPA-HQ-ORD-2009-0605. Additionally, the draft document and the charge questions for EPA's external peer review are available via the Internet on the Risk Assessment Forum's home page at http://www.epa.gov/raf/hhtefguidance.

In preparing a final report, EPA will consider the peer review report of the recommendations from the external peer review teleconference and any public comments that EPA receives in accordance with the September 2, 2009 notice (74 FR 45437) and at the public teleconference.

Dates:

The peer review teleconference will be held on October 22, 2009, from 1 p.m. to approximately 3:30 p.m. Registration for this teleconference is required (see How Can I Request to Participate in this Meeting?). Time will be provided for public observers who wish to make comments on the document. Members of the public will be allowed to make brief (no longer than 5 minutes) oral statements during the meeting's public comment period.

Addresses:

The draft “Recommended Toxicity Equivalency Factors (TEFs) for Human Health Risk Assessments of Dioxin and Dioxin-Like Compounds” is available primarily via the Internet on the Risk Assessment Forum's home page at http://www.epa.gov/raf/hhtefguidance. A limited number of paper copies are available from the Risk Assessment Forum. If you are requesting a paper copy, please provide your name, mailing address, and the document title, “Recommended Toxicity Equivalency Factors (TEFs) for Human Health Risk Assessments of Dioxin and Dioxin-Like Compounds,” to Seema Schappelle via the contact information below.

How Can I Request To Participate in This Meeting?

Members of the public may call into the teleconference as observers, and there will be a limited time for comments from the public. In order to participate, you should contact Ms. Kathy Coon of Versar, Inc. by e-mail at kscoon@versar.com(subject line: Dioxin TEF Peer Review Teleconference) or byphone at 703-750-3000 extension 545 to register. You will be asked for your name, affiliation, city and state, and contact information. When registering, please also indicate whether you would like to make a comment during the observer comment portion of the call. Time for public comments is limited, and reservations will be accepted on a first-come, first-served basis. Registered members of the public will be allowed to make brief (no longer than 5 minutes) oral statements during the meeting's public comment period. The call-in number for the meeting will be: Telephone: 1-877-558-5229; Pass Code: 7037503000#.

For technical information, please contact: Seema Schappelle, Risk Assessment Forum, Mail Code 8105R, Environmental Protection Agency, 1200 Pennsylvania Avenue, NW., Washington, DC 20460; telephone number: (202) 564-3372; fax number: (202) 564-2070, E-mail:schappelle.seema@epa.gov.

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 that typically 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 Risk Assessment Forum (RAF) identified a need to examine the 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 Equivalency Factors (TEFs) for Human Health Risk Assessments of Dioxin and Dioxin-Like Compounds,” to assist EPA scientists in using this 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. 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://cfpub.epa.gov/ncea/CFM/nceaQFind.cfm?keyword=Dioxin.

The draft document under review describes EPA's updated approach for evaluating the human health risks from exposures to environmental media containing dioxin-like compounds. It recommends the use of consensus TEF values for 2,3,7,8-tetrachlorodibenzo-p-dioxin and dioxin-like compounds, which were published in 2005 by the World Health Organization, and adopted by EPA in 2008 for ecological risk assessments.

The draft document was developed by the EPA's Risk Assessment Forum with extensive input from scientists throughout the Agency. The draft document summarizes the toxicity equivalence methodology, provides background information and assumptions on how the methodology has evolved, and provides health risk assessors with a recommended approach for application. It will 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.

Dated: October 9, 2009. Kevin Teichman,

Acting EPA Science Advisor.

References

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