As a result, existing data on exposures and health effects are inadequate not only for decisions on the management of hazardous-waste sites, but for epidemiologic investigations of the health impact of the sites as well.
Some states have mounted systematic discovery programs, have comprehensive inventories, and routinely undertake off-site sampling to identify potential human exposures. The California State Department of Health, in reviewing the 93 sites on the state's Superfund list in 1984, found that 19 of the sites were also on the federal NPL. Yet 46 of the sites showed evidence of waste release into groundwater, and in 34 of these cases the groundwater was known to be used for drinking. Extensive or systematic sampling existed for only 22 of the sites, despite the evidence of potential human exposure. In all 19 of the California sites with known contamination of groundwater, moreover, more than 10,000 persons were potentially exposed (Layefsky et al., 1988). Their experiences could serve as a model for the development of an effective discovery and initial assessment program. Such a program might rapidly establish public confidence that the “worst ” sites are aggressively sought and dealt with, and that Superfund resources are effectively applied to remove the most serious risks. Data collected by such a national program would also provide a comprehensive data base containing preliminary (and later, more refined) information on the substances known to be present at hazardous-waste sites, on the media contaminated, on the routes of exposure, and on the human populations potentially at risk.
Even without the establishment of a site discovery program, the development and validation of an adequate initial assessment methodology for hazardous-waste sites is an urgent recommendation of this committee. Epidemiology is not merely a passive science, cataloguing exposures and effects. It is an active tool for identifying potentially hazardous exposures and directing interventions to prevent further exposures. Because the evaluation of human exposures and health effects associated with hazardous-waste sites is not integrated into early site evaluation and interim remediation decisions, the real contributions of public health and epidemiology are lost.
This is of grave concern, because some hazardous wastes do constitute a significant public health hazard to specific populations at specific sites, as discussed in Chapter 4, Chapter 5, and Chapter 6. As ATSDR has documented, and other reports confirm, human exposure to hazardous-chemical releases are common at some of these sites. The health of the public has remained in jeopardy at many sites long after the risks could have—and should have—been identified (Hazardous Waste Treatment Council, 1990).