title: Comparison of organophosphorus pesticide metabolite levels in single and multiple daily urine samples collected from preschool children in Washington State.
abstract: A total organophosphorus pesticide exposure study was conducted in Washington State in 1998 in a sample population of 13 children aged 2.5-5.5 years. The children were roughly split between rural and suburban populations and had been previously identified as having potentially elevated organophosphorus pesticide exposures. One component of the study was urine collection and analysis. Urine samples were collected from each subject up to four times in 24 h in two different seasons. Samples were collected at specific time points: before bed, first morning void, after lunch, and before dinner. Urine samples were analyzed initially for the six nonspecific dialkylphosphate (DAP) metabolites and subsequently for eight specific metabolites including malathion dicarboxylic acid (MDA), 3,5,6-trichloro-2-pyridinol (TCPy), and paranitrophenol (PNP). Relatively large percentages of the urine samples contained quantifiable amounts of two of the nonspecific DAP metabolites (DMTP-97%; DETP-67%), and three of the specific metabolites (MDA (71%), TCPy (79%), and PNP (96%)). A percent deviation analysis was employed to determine which of the spot sample time points was the best predictor of the estimated volume-weighted daily average. Of the four spot samples collected, first morning void samples were consistently found to be the best predictors of weighted-average daily metabolite concentration. This finding also held when the data were creatinine-adjusted. The results of this analysis suggest that if spot sampling is to be conducted as part of a biological monitoring study, first morning void samples should be preferentially collected.
authors.affiliation: Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, University of Washington, Seattle, Washington 98195, USA. jkissel@u.washington.edu
authors.forename: John C
authors.initials: JC
authors.lastname: Kissel
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Curl
authors.forename: Golan
authors.initials: G
authors.lastname: Kedan
authors.forename: Chensheng
authors.initials: C
authors.lastname: Lu
authors.forename: William
authors.initials: W
authors.lastname: Griffith
authors.forename: Dana B
authors.initials: DB
authors.lastname: Barr
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Richard A
authors.initials: RA
authors.lastname: Fenske
mesh_terms: D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D009943:Organophosphorus Compounds / Q000378:metabolism* / Q000652:urine*; D010575:Pesticides / Q000378:metabolism* / Q000652:urine*; D015203:Reproducibility of Results; D012424:Rural Population; D013997:Time Factors; D016482:Urinalysis; D014861:Washington
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides