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Dietary Exposure to Pyrethroids in the U.S. Population
Rogelio Tornero-Velez1, Jianping Xue2, Edward Scollon3, James Starr2, Peter Egeghy2, Dana Barr4, Mike DeVito3 and Curtis Dary1
1 - National Exposure Research Laboratory, U.S. Environmental Protection Agency EPA, Las Vegas, NV;
2 - National Exposure Research Laboratory, U.S. Environmental Protection Agency EPA, Research Triangle Park, NC,
3 - National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC,
4 - National Center for Environmental Health, U.S. Centers for Disease Control and Prevention, Atlanta, GA.
Pyrethroids are a group of synthetic insecticides similar in structure to the pyrethrins, natural extracts of Chrysanthemum cinerariaefolium. In both insects and mammals pyrethroids target the nervous system, acting directly on voltage-gated sodium channels to modulate nerve firing. Because of their potency, pyrethroids are widely used in agriculture, commercial facilities, and in residential homes to control insect pests. As a consequence, pyrethroid residues present in foods or on treated surfaces may serve as sources of human exposure. However, the importance of individual routes of exposure (e.g., dietary, non-dietary ingestion, and dermal) remain unclear.
We examined the contribution of pyrethroid residues in food as a potential driver of exposure. The levels of urinary metabolites of pyrethroids reported through the 2001-2002 U.S. National Health and Nutrition Examination Survey (NHANES) were used as a general estimate of population exposure to pyrethroids.
Dietary exposure to these pyrethroids was estimated using U.S. Department of Agriculture's Continuing Survey of Food Intakes by Individual (CSFII) and Pesticide Data Program (PDP). A pharmacokinetic model of permethrin was used to account for absorption and excretion of urinary DCCA. Comparison of the predicted metabolites levels with values reported in NHANES suggests that dietary permethrin is a minor source of urinary DCCA.
Disclaimer: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.