Foliar Dislodgeable Residue Analysis: A New Scientific Approach to a Regulatory Concern
J. M. Van Emon1, C. L. Gerlach2, A. W. Reed1, B. C. Hardwick1
1U.S. Environmental Protection Agency, National Exposure Research Laboratory, Human Exposure Research Branch, P. 0. Box 93478, Las Vegas, NV 89193-3478
2Lockheed Martin Environmental Services, 980 Kelly Johnson Drive, Las Vegas, NV 89119
Received September 22, 1997
Accepted April 7, 1998
ch1orpyrifos, exposure monitoring, foliar dislodgeable residues, immunoassay
The U. S. Environmental Protection Agency and other federal and state regulators are interested in the presence and bioavailability of pesticide residues that remain on vegetation after application. These compounds can become an issue in human exposure if they become airborne and are inhaled, or if they are dermally absorbed by agricultural ivorkers. In an effort to measure the level and extent of these foliar dislodgeable residues, the EPA's Office of Prevention, Pesticides, and Toxic Substances has developed guidelines for sampling and analysis of leaf sections. The testing methods used meet the requirements of the Federal Insecticide, Fungicide, and Roden-licide Act. The advent of immunochemical methods for the analysis of many pesticides offers new, rapid, and sensitive analytical procedures for residue studies of these leaf extracts. This article describes the use of indirect competitive enzyme-linked immunosorbent assay on representative samples for the analysis of the pesticide chlorpyrifos. Results will be compared with those from the traditional high-performance liquid chromatography method.