| Use of Biomarkers to Indicate Exposure of Children to Organophosphate Pesticides: Implications for a Longitudinal Study of Children's Environmental Health Denise Wessels,1 Dana B. Barr,2 and Pauline Mendola3
1School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana, USA; 2Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA; 3National Health and Environmental Effects Research Laboratory, Human Studies Division, U.S. Environmental Protection Agency, Chapel Hill, North Carolina, USA Abstract
Because of their history of widespread use in the United States and unknown long-term health effects, organophosphate pesticides (OPs) are being considered as a chemical class of interest in planning for the National Children's Study, a longitudinal study of children's environmental health. The availability and appropriate use of biomarkers to determine absorbed doses of environmental chemicals such as OPs are critical issues. Biomarkers of OP exposure are typically measured in blood and urine ; however, postpartum meconium has been shown to be a promising matrix for assessing cumulative in utero exposure to the fetus, and studies are currently in progress to determine the utility of using saliva and amniotic fluid as matrices. In this article, we discuss the advantages and disadvantages of the currently available OP exposure monitoring methods (cholinesterase inhibition in blood, pesticides in blood, metabolites in urine and alternative matrices) ; study design issues for a large, long-term study of children's environmental health ; and current research and future research needs. Because OPs are rapidly metabolized and excreted, the utility of one-time spot measurements of OP biomarkers is questionable unless background exposure levels are relatively stable over time or a specific time frame of interest for the study is identified and samples are collected accordingly. Biomarkers of OP exposure can be a valuable tool in epidemiology of children's environmental health, as long as they are applied and interpreted appropriately. Key words: biomarkers, blood, children, exposure, meconium, organophosphate, pesticides, study design, urine. Environ Health Perspect 111:1939-1946 (2003) . doi:10.1289/ehp.6179 available via http://dx.doi.org/ [Online 10 September 2003]
Address correspondence to P. Mendola, 104 Mason Farm Rd., Chapel Hill, NC 27599-7315 USA. Telephone: (919) 966-6953. Fax: (919) 966-7584. E-mail: mendola.pauline@epa.gov This study was supported by the U.S. EPA National Network for Environmental Management Studies student fellowship program (U.S. EPA/Fellowship 91614101-0) . We gratefully acknowledge the contributions of S. McMaster and J. Quackenboss, who reviewed an earlier version of the manuscript. This article has been funded in part by the U.S. Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Approval does not signify that that the contents reflect the views of the Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. The authors declare they have no competing financial interests. Received 30 December 2002 ; accepted 11 September 2003.
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