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Review of National Primary Drinking Water Regulations: Health-Based Selection Criteria for Chemical Contaminants(This Issue Paper Is for Stakeholder Discussion and May Not Reflect Official EPA Policy) EPA has developed a preliminiary screening mechanism for identifying regulated chemicals that should be considered based on health effects. The resultant health-based approach for the selection of regulated chemicals that need to be reviewed is outlined below. ISSUES/ACTIVITIES Within EPA, the Office of Research and Development (ORD) through its Integrated Risk Information System (IRIS) and the Office of Pesticide Programs (OPP) have conducted, or are in the process of conducting, comprehensive new assessments of the toxicity of a number of chemicals for which EPA has set NPDWRs. Assessments by OPP and IRIS undergo internal and external peer reviews by health scientists. Where possible, an oral Reference Dose (RfD) is derived and carcinogenicity assessment from oral exposure conducted. Our selection criteria build on the availability of these peer reviewed assessments. The following criteria are proposed to identify chemical contaminants potentially requiring review:
Health-based considerations are only one part of the selection process. A final list of NPDWRs requiring further review and possible revision is to be developed based on additional considerations such as occurrence data and improvements in analytical techniques. Once the final list of NPDWRs requiring further review is available, i.e., as the full screening process is applied under the 6-year review, an up-to-date evaluation of the health effects information for the selected chemicals will be conducted by EPA. Such evaluations may include collecting any new information on reproductive and developmental effects, as well as any effect of these chemicals on sensitive sub-populations such as infants, children, pregnant women, the elderly, and the seriously ill. QUESTIONS
Please address written comments on the discussion questions to Marc Parrotta or Judy Lebowich, both at U.S. EPA, Office of Ground Water and Drinking Water, 401 M Street SW (MC 4607), Washington, DC 20460.
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