Six-Year Review, Chemical Contaminants, Health Effects Technical Support Document

摘要

The Environmental Protection Agency (EPA) has developed a 'Protocol for the Review of Existing National Primary Drinking Water Regulations' (USEPA, 2003a) based on recommendations of the National Drinking Water Advisory Council (NDWAC, 2000), through consultations with stakeholders representing a wide variety of interest groups, and internal Agency deliberations. The Protocol outlines the approach to be used to review and identify national primary drinking water regulations (NPDWRs) that warrant revision to maintain, or provide for greater, public health protection. The key elements of the review process are health effects, analytical and treatment technology, other regulatory revisions (e.g., monitoring and reporting requirements), occurrence and exposure analysis and, as appropriate, economic considerations. The purpose of the health effects component of the review process is to identify, within the limitations of the Agencys available resources, new health risk assessments that indicate possible change to the maximum contaminant level goal (MCLG) and, perhaps, to the maximum contaminant level (MCL). A total of 68 regulated chemical contaminants are being considered during this first Six- Year Review cycle. These are inorganic and organic contaminants regulated prior to the Safe Drinking Water Act (SDWA) 1996 Amendments, except arsenic, radionuclides, disinfectant residuals, and disinfection by-products, which are being or have already been reviewed in separate actions.