Application of Soil Contact Rates to Dermal Pathway Exposure Assessment. J. Kissel and J. Shirai, University of Washington, Dept. of Environmental Health, Seattle, WA; and T. Garlock, Shannon and Wilson, Inc., Seattle, WA
Traditional regulatory protocols for estimation of exposures to soil contaminants via dermal contact utilize soil loadings expressed as mass per area per event and avoid explicit treatment of time dependent absorption kinetics. An alternative approach, based on field measurements of soil loadings on multiple body parts and telephone survey responses regarding activity patterns, clothing choices, and bathing habits, has been developed. This approach utilizes soil contact rate (SCR) estimates expressed in g hr/mo. For an adult residential scenario, current best estimates are on the order of 10-20 g hr/mo. (At the time of abstract submission, estimates for children were in preparation.) Expression of soil exposure in terms of a SCR provides an opportunity for explicit consideration of time dependent absorption. This is most easily accomplished if absorption can be assumed to be linear with time and if all local loadings are assumed to be monolayer or less. Limitations on these assumptions will be discussed.
Supported by USEPA and USDOE under agreements CR824065-01-0 and DE-FC01-95EW55084, respectively.
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