Recommended Distributions for Exposure Factors Frequently Used in Health Risk Assessment |
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Authors: | Brent Finley Deborah Proctor Paul Scott Natalie Harrington Dennis Paustenbach Paul Price |
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Affiliation: | ChemRisk–a division of McLaren/Hart Environmental Engineering.;1135 Atlantic Avenue, Alameda, California 94501.;The Courtland East Building, 29225 Chagrin Boulevard, Cleveland, Ohio 44122.;Stroudwater Crossing, 1685 Congress Street, Portland, Maine 04102. |
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Abstract: | Although there has been nearly complete agreement in the scientific community that Monte Carlo techniques represent a significant improvement in the exposure assessment process, virtually all state and federal risk assessments still rely on the traditional point estimate approach. One of the rate-determining steps to a timely implementation of Monte Carlo techniques to regulatory decision making is the development of "standard" data distributions that are considered applicable to any setting. For many exposure variables, there is no need to wait any longer to adopt Monte Carlo techniques into regulatory policy since there is a wealth of data from which a robust distribution can be developed and ample evidence to indicate that the variable is not significantly influenced by site-specific conditions. In this paper, we propose several distributions that can be considered standard and customary for most settings. Age-specific distributions for soil ingestion rates, inhalation rates, body weights, skin surface area, tapwater and fish consumption, residential occupancy and occupational tenure, and soil-on-skin adherence were developed. For each distribution offered in this paper, we discuss the adequacy of the database, derivation of the distribution, and applicability of the distribution to various settings and conditions. |
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Keywords: | Probability distributions exposure factors risk assessment Monte Carlo analysis |
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