99-32181. Summary of the U.S. EPA Workshop on the Relationship Between Exposure Duration and Toxicity

[Federal Register Volume 64, Number 238 (Monday, December 13, 1999)]
[Notices]
[Page 69530]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-32181]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6507-3]


Summary of the U.S. EPA Workshop on the Relationship Between 
Exposure Duration and Toxicity

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability of a final report.

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SUMMARY: The notice announces the availability of a final report, 
Summary of the U.S. EPA Workshop on the Relationship Between Exposure 
Duration and Toxicity (EPA/600/R-99/081, September 1999). This report 
was prepared by Eastern Research Group, Inc. (ERG), for the U.S. 
Environmental Protection Agency's (EPA) National Center for 
Environmental Assessment (NCEA), within the Office of Research and 
Development (ORD). Current risk assessment procedures are typically 
based on overall daily exposure levels and tend to emphasize effects 
resulting from continuous exposure over a lifetime. Scientists now 
realize that exposures are more likely to be experienced as bursts or 
spikes, or intermittent exposures of varying levels. EPA's Risk 
Assessment forum is beginning to examine how dose-duration 
relationships are or can be incorporated into the risk assessment 
process for less-than-lifetime exposures. As part of this effort, the 
Forum and the Harvard School of Public Health, held a workshop on 
August 5-6, 1998, to discuss the current understanding of dose-duration 
relationships, the approaches that can be used in their modeling, the 
inclusion of these relationships in risk assessment, and future 
directions in this area. The workshop provided a forum for open 
discussion and identifying areas of consensus, as well as areas of 
difference.

ADDRESSES: A limited number of paper copies will be available from the 
EPA's National Service Center for Environmental Publications (NSCEP), 
P.O. Box 42419, Cincinnati, OH 45242; telephone: [phone] or 513-
489-8190; facsimile: 513-489-8695 on or about December 17, 1999. Please 
provide your name and mailing address and the title and EPA number of 
the requested publication. The document is not available in electronic 
form.

FOR FURTHER INFORMATION CONTACT: Dr. Gary Kimmel, National Center for 
Environmental Assessment-Washington Office (8623D), U.S. Environmental 
Protection Agency, Washington, DC 20460; telephone: [phone]; 
facsimile: 202-565-0078; email:[e-mail].

    Dated: December 3, 1999.
William H. Farland,
Director, National Center for Environmental Assessment.
[FR Doc. 99-32181 Filed 12-10-99; 8:45 am]
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