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MEASUREMENT OF CHILDREN'S EXPOSURE TO PESTICIDES: ANALYSIS OF URINARY METABOLITE LEVELS IN A PROBABILITY-BASED SAMPLE
Citation:
Adgate, J. L., D. Barr, C. A. Clayton, L. E. Eberly, N. G. Freeman, P. J. Lioy, L. Needham, E. D. Pellizzari, J J. Quackenboss, A. Roy, AND K. G. Sexton. MEASUREMENT OF CHILDREN'S EXPOSURE TO PESTICIDES: ANALYSIS OF URINARY METABOLITE LEVELS IN A PROBABILITY-BASED SAMPLE. ENVIRONMENTAL HEALTH PERSPECTIVES 109(6):583-590, (2001).
Impact/Purpose:
The objectives for the current task are to 1) evaluate the utility of screening survey design and questionnaires for identifying households/individuals with higher exposures; and 2) compare estimates of dietary exposure derived from food consumption and residue databases with direct measurements of dietary exposure obtained in this study. (Results of the environmental, exposure, and biological measurements will be reported in collaboration with the other investigators.)
Description:
The Minnesota Children's Pesticide Exposure Study is a probability-based sample of 102 children 3-13 years old who were monitored for commonly used pesticides. During the summer of 1997, first-morning-void urine samples (1-3 per child) were obtained for 88% of study children and analyzed for metabolites of insecticides and herbicides: carbamates and related compounds (1-NAP), atrazine (AM),malathion (MDA), and chlorpyrifos and related compounds (TCPy). TCPy was present in 93% of the samples, whereas 1-NAP, MDA, and AM were detected in 45%, 37%, and 2% of samples, respectively. Measured intrachild means ranged from 1.4 ug/L for MDA to 9.2 ug/L for TCPy, and there was considerable intrachild variability. For children providing three urine samples, geometric mean TCPy levels were greater than the detection limit in 98% of the samples, and nearly half the children had geometric mean 1-NAP and MDA levels greater than the detection limit. Interchild variability was significantly greater than intrachild variability for 1-NAP (p = 0.0037) and TCPy (p < 0.0001). The four metabolites measured were not correlated within urine samples, and children's metabolite levels did not vary systematically by sex, age, race, household income, or putative household pesticide use. On a log scale, mean TCPy levels were significantly higher in urban than in nonurban children (7.2 vs. 4.7 ug/L; p = 0.036). Weighted population mean concentrations were 3.9 [standard error (SE) = 0.7; 95% confidence interval (CI), 2.5, 5.3] ug/L for 1-NAP, 1.7 (SE = 0.3; 95% CI, 1.1, 2.3) ug/L for MDA, and 9.6 (SE = 0.9; 95% CI, 7.8, 11) ug/L for TCPy. The weighted population results estimate the overall mean and variability of metabolite levels for more than 84,000 children in the census tracts sampled. Levels of 1-NAP were lower than reported adult reference range concentrations, whereas TCPy concentrations were substantially higher. Concentrations of MDA were detected more frequently and found at higher levels in children than in a recent nonprobability-based sample of adults. Overall, Minnesota children's TCPy and MDA levels were higher than in recent population-based studies of adults in the United States, but the relative magnitude of intraindividual variability was similar for adults and children.
(This article has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for publication.)