| Abstract: | In 1980 the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) was passed to instigate the cleanup of uncontrolled hazardous waste sites. CERCLA necessitated the development of a set of criteria for estimating the severity of the contamination at these sites, the potential impact on human health and the environment, and establishing appropriate cleanup levels for the contaminated media. The risk assessment (RA) format was developed to meet these challenges. Though RAs vary dramatically in their scope, emphasis, and regulatory application, there are two primary objectives common to all RAs: (1) to evaluate potential risks to human health and the environment posed by the release of hazardous substances and (2) to evaluate and establish safe cleanup levels based primarily on the number and type of potential receptors, the toxicity and mobility of the contaminants, and the types of exposure pathways present. Achieving these objectives may be a relatively simple task or an extremely complex and difficult one depending on the type of material released and our understanding of its behavior in the environment, the site conditions, and the governing regulations. This article presents an approach for establishing acceptable cleanup levels for subsurface soils and illustrates the application of this approach to three different regulated sites. |
