trated by Lioy et al. (1988) as these authors sought to define total exposure to benzopyrene (BAP). The study was carried out in Phillipsburg, New Jersey, where there is a metal pipe foundry. The foundry was the point source for BAP emissions and could represent a surrogate for a hazardous-waste site. In this study indoor and outdoor air, food, and water exposure analyses were conducted. Additional multimedia studies of this type will be useful in defining protocols for exposure assessment at hazardous-waste sites.
This section addresses what constitutes appropriate approaches to the measurement of exposure in order to identify and characterize an exposed population and then considers potential problems in the estimation of exposure to the public associated with hazardous-waste sites.
ATSDR health assessments could be important sources of information about the possible routes of human exposure and the types and amounts of hazardous materials present at NPL sites. The conceptual model ATSDR has adopted for conducting its health assessments seeks to emphasize early identification of potential public health problems and interventions that would ameliorate problems at a site. The health assessments have generally not been published in the peer-reviewed literature and are therefore not within the scope of this report. The committee has reviewed the abstracts for the 951 health assessments and evaluated some assessments in detail.
The assessments provide information about the specific toxic chemicals found at NPL sites, the degree of contamination, and potential routes of off-site exposure of the public. There is little information about the degree of off-site contamination. Virtually no information about actual exposure to the public is derived from personal sampling, direct measurement of exposure of individuals, or total exposure assessment modeling. The ATSDR health assessments are in reality hazard assessments with limited information about potential human health effects from off-site migration of chemical wastes. They do not constitute epidemiologic investigations nor were they intended to be used for those purposes. They provide a starting point for epidemiologic investigations, insofar as they contain information about some of the chemicals identified at hazardous-waste sites. Their lack of information on the fate and transport of contaminants and on exposures of persons near the sites makes them of limited use for identification of a potentially exposed population in environmental epidemiologic investigations.