Military-Specific Exposure Factors Study

Abstract

Abstract : The Environmental Protection Agency's (EPA's) recently revised (August 1997) Exposure Factors Handbook (EFH) provides many factors needed in the assessment of human health risk that were derived from general population studies or studies involving relatively small groups that may not be representative of military populations. This short term study assessed the differences between exposure factors presented in the EPA's EFH and those based upon military specific data. Military factors data sets that were identified, evaluated, and selected for sensitivity analysis using Crystal Ball software included: drinking water consumption, activity specific inhalation rates, body weights, body surface areas, and on base residence times of military populations. In comparison of risk for a hypothetical dermal exposure of benzene, the risk was nominally reduced from 3.3E-7 (EFH factors) to 1.0E-7 (military factors). This was due to the shorter military exposure duration. In contrast, the ground water ingestion risk was increased from 7.2E-5 (EFH factors) to 1.2E-4 (military factors). This was due to the increased military drinking water consumption in comparison to the U.S. population. The inhalation route risk was marginally reduced from 7.04E-4 (EFH factors) to 2.8E-4 (military factors) due to the decreased exposure duration. The study also identified additional military specific data involving food consumption, site specific housing data, and population mobility that were either not acquired or not analyzed because of the time constraints of the study. Further investigation would be necessary to locate other military studies that could provide dermal contact data, incidental soil ingestion data, and activity pattern data (e.g., time spent outdoors, time spent showering, time spent swimming, time spent gardening).