| Biologic Monitoring to Characterize Organophosphorus Pesticide Exposure among Children and Workers: An Analysis of Recent Studies in Washington State Richard A. Fenske,1 Chensheng Lu,2 Cynthia L. Curl,3 Jeffry H. Shirai,1 and John C. Kissel1 1Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, University of Washington, Seattle, Washington, USA; 2Department of Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA; 3Integral Consulting Inc., Boulder, Colorado, USA Abstract
We examined findings from five organophosphorus pesticide biomonitoring studies conducted in Washington State between 1994 and 1999. We compared urinary dimethylthiophosphate (DMTP) concentrations for all study groups and composite dimethyl alkylphosphate (DMAP) concentrations for selected groups. Children of pesticide applicators had substantially higher metabolite levels than did Seattle children and farmworker children (median DMTP, 25 µg/L ; p < 0.0001) . Metabolite levels of children living in agricultural communities were elevated during periods of crop spraying. Median DMTP concentrations for Seattle children and farmworker children did not differ significantly (6.1 and 5.8 µg/L DMTP, respectively ; p = 0.73) ; however, the DMAP concentrations were higher for Seattle children than for farmworker children (117 and 87 nmol/L DMAP, respectively ; p = 0.007) . DMTP concentrations of U.S. children 6-11 years of age (1999-2000 National Health and Nutrition Examination Survey population) were higher than those of Seattle children and farmworker children at the 75th, 90th, and 95th percentiles. DMTP concentrations for workers actively engaged in apple thinning were 50 times higher than DMTP concentrations for farmworkers sampled outside of peak exposure periods. We conclude that workers who have direct contact with pesticides should continue to be the focus of public health interventions and that elevated child exposures in agricultural communities may occur during active crop-spraying periods and from living with a pesticide applicator. Timing of sample collection is critical for the proper interpretation of pesticide biomarkers excreted relatively soon after exposure. We surmise that differences in dietary exposure can explain the similar exposures observed among farmworker children, children living in the Seattle metropolitan area, and children sampled nationally. Key words: agricultural communities, agricultural workers, biologic monitoring, children, dialkylphosphates, organophosphorus pesticides, pesticide exposure. Environ Health Perspect 113:1651-1657 (2005) . doi:10.1289/ehp.8022 available via http://dx.doi.org/ [Online 6 July 2005]
Address correspondence to R.A. Fenske, University of Washington, Box 357234, Health Sciences Building, F-233, 1959 N.E. Pacific St., Seattle, WA 98195-7234 USA. Telephone: (206) 543-0916. Fax: (206) 616-2687. E-mail: rfenske@u.washington.edu Contributors to the studies discussed include J. Camp, G. Coronado, I. Islas, C. Loewenherz, G. Kedan, D. Knutson, D. Koch, T. Moate, N. Simcox, and B. Thompson. This work was supported by the U.S. Environmental Protection Agency (EPA) STAR program (R819186) , the National Institute for Occupational Safety and Health Agricultural Centers program (U07/CCU012926) , and the EPA/National Institute of Environmental Health Sciences Child Health Center program (R826886/PO1ES09601) . Contents are the responsibility of the authors and do not necessarily represent the official view of these agencies. The authors declare they have no competing financial interests. Received 16 February 2005 ; accepted 6 July 2005.
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