Exposure assessment and biological monitoring of organophosphate pesticides among pesticides factory employees

• Main Authors: Jer-Pei Fang, 方澤沛
• Other Authors: Ho-Yuan Chang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/27067628250607620547

碩士 === 國立成功大學 === 環境醫學研究所 === 89 === Organophosphorous pesticides (OP) are one of most common agrochemicals used in agricultural activities. Through the blockage of acetyl cholinesterase, exposure to organophosphates can cause neurological perturbation. There are two main highly occupationally exposed groups: farmers and pesticide manufacturing workers. This study was aimed to develop the relationship between occupational exposure to OP and its corresponding biological monitoring among pesticide workers. The occupational exposure to OP included two routes of exposure: inhalation and skin. The time-series urinary alkylphosphate concentrations, prepared by SAX extraction technique and analyzed by GC/FPD, were used as biomarkers for biological monitoring. By integrating physiological based pharmacokinetic (PBPK) modeling, this study was able to estimate the contribution of various exposure routes, the concentration profiles in various organs in the human body. The study subjects were 21 workers, who were occupationally exposed to malathion, phorate, and ethion, selected from three pesticide manufacturing factories located in Northern and Middle Taiwan. Skin exposure was assessed in addition to the exposure through respiration. Urinary alkylphosphate levels in twenty-four hour complete urine were used as biomarkers. An eight-compartment PBPK model was applied to explore the simultaneous exposure to respiratory and dermal chloropyrifos at the level of 0.2 mg/m3 (TVL) for eight hours. Twenty-four hour urinary DEPT, the corresponding metabolite of chloropyrifos, were observed. Based on each parameter distribution obtained from the literature, the distribution of time-series concentrations of urinary DETP for a-thousand population was explored by the Monte Carlo technique. We found the exposure via the skin, especially, that via the hand, is dominant among all routes of the exposure to OP. Time-independent analysis revealed that the highest correlation between the exposure and biomarker occurs at the time when urine samples collected immediately after the exposure terminated. According to the 95 % of the projected value from 1000 repeated simulation results based on PBPK modeling integrated to the Monte Carlo technique, the appropriate BEI value for chloropyrifos exposure should be 2.236 nmole/mmole_cre, and the most recommended timing for urine collection be immediately after the end of workshift.