Human health risk assessment of endosulfan. Part IV: Occupational reentry and public non-dietary exposure and risk

The California Department of Pesticide Regulation (CDPR) and the United States Environmental Protection Agency (USEPA) released revised draft risk assessments for the pesticidal active ingredient, endosulfan, just 2 months apart, in November 2007 and January 2008. The exposure estimates, critical to risk assessment, were calculated by each agency using dissimilar approaches in certain aspects. The scenarios for which exposures and risks were estimated also varied somewhat between the two agencies, although there were substantial overlaps that allowed specific comparisons of exposure and risk estimates. Reasons underlying major differences in estimates of exposure for field workers working in treated crops (reentry exposure) are discussed in this paper. Differences in dislodgeable foliar residue levels calculated by CDPR and USEPA, reflecting endosulfan residues encountered by field workers entering treated orchards and fields, contributed the most to discrepancies in reentry exposure estimates between the two agencies. Additionally, because of differences in legal mandates CDPR estimated exposures for members of the public exposed to endosulfan in ambient air and when swimming, whereas USEPA did not. Exposures calculated for bystanders adjacent to a pesticide application suggest a potential health concern, but estimated swimmer exposures did not.