title: Chlorpyrifos exposure in farmers and urban adults: Metabolic characteristic, exposure estimation, and potential effect of oxidative damage.
abstract: Chlorpyrifos is a widely used organophosphorus pesticide that efficiently protects crops against pests. However, recent studies suggest that severe exposure to chlorpyrifos may present adverse health effects in human. To analyze the exposure level and metabolic characteristics of chlorpyrifos pesticide in urban adults and farmers with/without occupation pesticide contact, the occurrence of urinary chlorpyrifos and methyl chlorpyrifos (CP-me), as well as their metabolite, 3,5,6-trichloro-2-pyridinol (TCPy), was determined in farmers of an agricultural village in China, and in urban adults of a nearby town. The geometric mean (GM) concentrations of TCPy, which is the major marker of chlorpyrifos exposure, were 4.29 and 7.57μg/g-creatinine in urban adults and farmers before pesticide application, respectively. Chlorpyrifos spraying significantly increased the concentrations of urinary TCPy. In the first day after spraying, a GM concentration of 43.7μg/g-creatinine was detected in the urine specimens from farmers, which decreased to 38.1 and 22.8μg/g-creatinine in the second and third day after chlorpyrifos spraying. The ratio of TCPy and its parent compounds, i.e. chlorpyrifos and CP-me, was positively associated with the sum concentration of urinary chlorpyrifos, CP-me, and TCPy, suggesting the increasing metabolic efficiency of chlorpyrifos to TCPy at higher chlorpyrifos exposure levels. To estimate the farmers' occupational exposure to chlorpyrifos pesticide, a new model based on the fitted first-order elimination kinetics of TCPy was established. Occupational chlorpyrifos exposure in a farmer was estimated to be 3.70μg/kg-bw/day (GM), which is an exposure level that is higher than the recommended guideline levels. Significant increase of urinary 8-hydroxydeoxyguanosine (8-OHdG) was observed on the first day after chlorpyrifos spraying, which indicates a potential oxidative damage in farmers. However, urinary 8-OHdG returned to its baseline level within two days.
authors.affiliation: Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China. Electronic address: wang2007@nankai.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Tianjin Centers for Disease Control and Prevention, Tianjin 300171, China.
authors.forename: Yinghong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300071, China.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Sun
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine; D002681:China; D004390:Chlorpyrifos / Q000031:analogs & derivatives* / Q000633:toxicity* / Q000652:urine; D002947:Cities; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity* / Q000652:urine; D000067565:Farmers; D005260:Female; D006801:Humans; D007306:Insecticides / Q000633:toxicity* / Q000652:urine; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D018384:Oxidative Stress / Q000187:drug effects*; D011728:Pyridones / Q000633:toxicity / Q000652:urine; D012737:Sex Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D004785:Environmental Pollutants; D007306:Insecticides; D011728:Pyridones; C012587:3,5,6-trichloro-2-pyridinol; D004390:Chlorpyrifos; C007031:chlorpyrifos-methyl
keywords: 8-Hydroxydeoxyguanosine (8-OHdG); Biomonitoring; Chlorpyrifos; Exposure estimation; Metabolic characteristic