ABSTRACT
Human and other biotic components of the environment are typically exposed to hazardous materials by a wide range of potential pathways. Exposures may occur via multiple routes and media. Risk assessments based on such exposure scenarios are conducted on different levels, depending on the goals of the assessment efforts available, associated level of refinement of the risk assessment tools, and data availability. Several methods have been developed that include screening, prioritization, protection, or prediction of the human health risk as a result of exposure to hazardous chemicals. The data requirement for each of these methods varies significantly. Most often, the criteria for the application of a method or a tool will be dictated by data availability as illustrated in this paper through two multiroute, multimedia case studies, namely, incinerator emissions and lead risk assessment.
Approaches currently available for the characterization of such exposures are limited by their ability to integrate multiroute scenarios. Lead is a unique toxicant for which there is a lack of empirical evidence for a physiological threshold. Since there exists a robust data base on this chemical, a predictive model has been developed that integrates its exposure and pharmacokinetics. This model is flexible and illustrates a useful approach for integrated site-and situation-specific risk assessment using empirical data and/or default assumptions for a wide range of physiological and exposure parameters.
