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EPA TCDD notice

  [Federal Register: December 24, 1997 (Volume 62, Number 247)]
  [Page 67361-67362]
  >From the Federal Register Online via GPO Access [wais.access.gpo.gov]
  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.
  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]
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