BIOLOGICAL MONITORING OF ORGANOPHOSPHORUS PESTICIDE EXPOSURE AMONG CHILDREN OF AGRICULTURAL-WORKERS IN CENTRAL WASHINGTON-STATE

Children up to 6 years of age who lived with pesticide applicators wer e monitored for increased risk of pesticide exposure. 48 pesticide app licator and 14 reference families sere recruited from an agricultural region of Washington State in June 1995. A total of 160 spot urine sam ples were collected from 88 children, including repeated measures 3-7 days apart. Samples were assayed by gas chromatography flame photometr ic detector for dimethylphosphate metabolites. Dimethylthiophosphate ( DMTP) was the dominant metabolite. DMTP levels were significantly high er in applicator children than in reference children (p = 0.015), with median concentrations of 0.021 and 0.005 mu g/ml, respectively; maxim um concentrations were 0.44 and 0.10 mu g/ml, respectively. Percentage s of detectable samples were 47% for applicator children and 27% for r eference children. A marginally significant trend of increasing concen trations observed with decreasing age among applicator children (p = 0 .060), and younger children within these families had significantly hi gher for concentrations when compared to their older siblings (p = 0.0 40). Applicator children living less than 200 feet from an orchard wer e associated with higher frequency of detectable DMTP levels than nonp roximal applicator children (p = 0.036). These results indicate that a pplicator children experienced higher organophosphorus pesticide expos ures than did reference children in the same community and that proxim ity to spraying is an important contributor to such exposures. Trends related ro age suggest that child activity is an important variable fo r exposure, it is unlikely that any of the observed exposures posed a hazard of acute intoxication. This study points to the need for a more detailed understanding of pesticide exposure pathways for children of agricultural workers.