Study To Test the Feasibility of Using the Macroactivity Approach To Assess Dermal Exposure. E. A. Hubal, L. S. Sheldon, G. Akland, D. Whitaker, and J. Raymer; US EPA National Exposure Research Laboratory, and Research Triangle Institute
In the macroactivity approach, dermal exposure is estimated using empirically-derived transfer coefficients to aggregate mass transfer associated with a series of contacts with a contaminated medium. The macroactivity approach affords the possibility of developing screening level exposure assessments more quickly and with fewer resources than the microactivity approach (in which exposure is explicitly modeled as a series of discrete transfers). However, the macroactivity approach was developed to assess occupational exposure in agricultural settings where workers are exposed to a relatively homogeneous environment. The macroactivity approach will only be useful in residential settings if exposure can be adequately quantified by lumping children’s activities into a few macroactivities. To assess the feasibility of the macroactivity approach for assessing children’s exposure to pesticides, a screening study was conducted with young children in a daycare center after a known pesticide application. Four or five children from each of two age groups were monitored for short periods while involved in selected macroactivities. The children were clothed in full-body dosimeters and transferable residues were sampled in the areas where the children spent time. Videotaping was conducted to verify the children’s activity levels and location. Dermal loading and transferable residue measurements were used to calculate transfer coefficients. The results demonstrate the variability of dermal loading (and associated transfer coefficients) for children of a given age group performing varying macroactivities. These data will be used to evaluate the default assumptions currently used in USEPA’s Office of Pesticide Programs to assess children’s residential exposure to pesticides.
This work has been funded wholly or in part by the United States Environmental Protection Agency under contract no. 68-D-99-012 to Research Triangle Institute. It has been subjected to Agency review and approved for publication.
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