[Federal Register Volume 62, Number 247 (Wednesday, December 24, 1997)]
[Notices]
[Pages 67361-67362]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-33736]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-5941-2]


Technical Workshop on the Potential for Application of 2,3,7,8-
TCDD Toxicity Equivalency Factors to Aquatic Life and Wildlife

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of meeting.

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SUMMARY: EPA is announcing a workshop to evaluate the application of 
toxicity equivalency factors (TEFs) for 2,3,7,8-TCDD to the assessment 
of risks from polychlorinated dioxins, furans, and biphenyls to 
terrestrial and aquatic wildlife. The workshop will be open to members 
of the public as observers. The application of TEFs, which are based on 
different experimental systems and varying amounts of empirical data, 
will be studied in the context of representative case studies.

DATES: The workshop will begin on Tuesday, January 20, 1998, at 3 p.m. 
and end on Thursday, January 22, 1998, at 5 p.m. Members of the public 
may attend as observers.

ADDRESSES: The meeting will be held at the Chicago Hilton and Towers, 
720 S. Michigan Ave., Chicago, IL 60605, Telephone (312) 922-4400.

FOR FURTHER INFORMATION CONTACT: For technical inquiries, contact 
Cynthia Nolt, U.S. EPA Office of Science Policy (8104R), 401 M Street 
SW, Washington, DC 20460, Telephone (202) 564-6763. Eastern Research 
Group, Inc., an EPA contractor, is convening this workshop. To attend 
the workshop as an observer, contact Eastern Research Group, Inc., 
Telephone (781) 674-7374.

SUPPLEMENTARY INFORMATION: The purpose of the workshop is to explore 
the application of additivity models for polychlorinated dioxins, 
furans, and biphenyls in problem formulations and effects 
characterizations of ecological risk assessments for aquatic life and 
avian and mammalian wildlife. In two previous workshops, convened by 
the World Health Organization in August 1996 and June 1997, scientific 
experts reached consensus on a scheme for prioritizing data sets and 
TEFs for aquatic life and wildlife. This third workshop will examine 
the use of a TEF approach in effects characterization in prospective 
risk assessments, as well as in retrospective risk assessments, where 
it may be applied as a diagnostic tool to assess relative risk.
    The workshop will consist of three panels that are to address 
uncertainties, such as lack of knowledge and variability, associated 
with WHO consensus TEFs (and the data sets for aquatic, avian, and 
mammalian wildlife from which the TEFs were determined), in the context 
of two risk assessment case studies. The prospective case study 
involves a risk assessment for a hypothetical point source requiring a 
water quality permit with standards that will protect aquatic life and 
wildlife at the individual and population levels of biological 
organization. The retrospective case study focuses on a hypothetical 
freshwater ecosystem in which scientists have observed reproductive 
effects and have measured exposures in both biota and sediments. The 
panels will relate the exposure levels to a concentration of concern 
and a threshold for remediation.
    To focus the workshop, the deliberations will address only 
compounds whose mode of action is elicited through the arylhydrocarbon 
receptor (AhR). The workshop will not address either chemicals with 
different modes of action or nonchemical stressors. In addition, the 
workshop deliberations will be restricted to the direct effects of AhR 
agonists, and will

[[Page 67362]]

not involve evaluations of indirect effects.
    Each panel will be composed of experts from the public and private 
sector. They will use the two case studies to evaluate how the nature 
and extent of uncertainties associated with the TEF approach and with 
associated data sets can have varying implications in different types 
of risk assessments. The results of the workshop will be compiled and 
summarized by Eastern Research Group in a workshop report. The 
availability of this workshop report will be announced in a future 
Federal Register document.

    Dated: December 19, 1997.
William H. Farland,
Director, National Center for Environmental Assessment.
[FR Doc. 97-33736 Filed 12-23-97; 8:45 am]
BILLING CODE 6560-50-P