Excerpt
The Safe Drinking Water Act of 1974 (PL93-523) required the Administrator of the Environmental Protection Agency to arrange for a study that would serve as a scientific basis for revising the primary drinking-water regulations that were promulgated under the Act. The Study was conducted by the Safe Drinking Water Committee of the National Research Council. A thorough study of the scientific literature was undertaken in order to assess the implications for human health of the constituents of drinking water in the United States. Assessment of the health benefits and the economic or technological feasibility of achieving a given level of contaminant control was outside the scope of the study, although the beneficial effects of some constituents of drinking water were considered. The risk to man of contaminants ingested in drinking water was evaluated on the basis of both epidemiological studies and studies of toxicity in laboratory animals. The theoretical and experimental bases for extrapolating estimations of risk to low levels of dose were reviewed, and some principles to guide the conduct of this and future studies were defined. Five classes of contaminants were examined: Microorganisms, Particulate Matter, Inorganic Solutes, Organic Solutes, and Radionuclides.