Variability in Occupational Exposures and Implications on Exposure Assessment and Biological Monitoring Outcomes

[[abstract]]以往進行職業暴露評估的方式，主要以個人採樣的方式進行，評估勞工在工作時暴露於危害物質之日時量平均濃度 (Time-Weighted Average Concentration, TWA)，用來代表 勞工在工作期間承受危害物質之平均暴露濃度，但此評估方式並不足以描述暴露濃度的 變異性，且當暴露物質可能因短期高濃度暴露而造成危害時，此種暴露評估資料可能無 法及時反映潛在危害的問題所在。本計畫以二甲基甲醯胺的職業暴露評估為例，探討勞 工在工作期間，承受二甲基甲醯胺的暴露特性及其變化情形，探討造成暴露濃度差異的 原因，不同暴露狀況對生物偵測結果之影響性。 本年度觀察某人造皮工廠員工 20 人，共收集七天 131 個樣本。其中空氣採樣濃度顯 示有相當比例超出法定暴露濃度上限，生物偵測結果也反映暴露濃度偏高的情形。夏季 測量的結果明顯高於冬季，應與氣溫造成揮發程度不同有關。本年度研究結果顯示相同 工作職稱之員工暴露濃度差異仍大，是否因工作項目或工作習慣影響所致，仍需進一步 探討。[[abstract]]Occupational exposure assessment often relies on limited personal monitoring data that, although sufficient for determining attainment of regulatory standards, do not necessarily reflect exposure characteristics, e.g., variability of exposure concentration and exposure patterns. This study investigated how different exposure characteristics might affect the biological monitoring outcomes. Twenty synthetic leather factory workers were recruited in this study to measure work-related exposure to N,N-dimethylformamide (DMF). In addition, urine samples were collected before and at the end of the workshift. In all, samples were taken during seven work days in August 2003 and February 2004, totaling 131 samples. Personal air samples collected with passive samplers revealed exposure levels substantially higher than the regulatory limit of 10 ppm, and people with high exposure levels also showed substantially higher urinary biomarker levels at the end of the work shift. Substantial variation was seen among workers with the same job descripter, suggesting that work department may not be an adequate indicator or exposure levels. Finally, only a weak correlation was found between biomarker and the TWA levels. Further assessment on the exposure variability during the work shift may help better descrobe the occupational exposure.[[note]]NSC92-2320-B327-00