Integrated Exposure and Dose Modeling and Analysis System. 1. Formulation and Testing of Microenvironmental and Pharmacokinetic Components

The conceptual and theoretical framework for a modular integrated Exposure and Dose Modeling and Analysis System (EDMAS) has been formulated, and its stepwise implementation and testing is currently in progress. This system aims to provide state-of-the-art tools for performing integrated assessments of exposure and dose for individuals and populations. The integration of modeling components with each other as well as with available environmental, exposure, and toxicological databases is being ac complished with the use of computational tools that include interactive simulation environments, Geographical Informa tion Systems, and various data retrieval, management, statistical analysis, and visualization methods. This paper overviews the structure and modular nature of this integrated modeling system and focuses specifically on two of its components: (a) a hierarchy of physiologically based pharmacokinetic models (PBPKM), representing various levels of detail and sophistication, and (b) a family of microenvironmental models, that incorporate complex physical and chemical transformations. The deterministic implementation of these components is also presented here in two test applications: (i) a case study of benzene exposure indoors resulting from the volatilization of contaminated tap water and (ii) a case study of photochemical pollution infiltration indoors, in an office building environ ment.