石化廠作業勞工揮發性有機化合物暴露評估

Exposure Assessment of Volatile Organic Compounds for Workers in Petrochemical Factories

朱偉銘(Wei-Ming Chu)

指導教授 ： 吳俊德

長榮大學/健康科學學院/職業安全與衛生學系(所)/碩士(2013年)

https://doi.org/10.6833/CJCU.2013.00205

摘要

本研究針對某石化廠區的六個工廠，依據全面性暴露評估策略建立各工廠作業勞工的相似暴露群組，擬定其作業環境測定實施計畫，並根據計畫針對作業環境空氣中苯、甲苯、二甲苯、乙苯、正己烷、四氫呋喃、乙酸丁酯、丙酮、1,2-二氯乙烷、甲基異丁酮、苯乙烯、丙烯腈和1,3-丁二烯等13種揮發性有機化合物，實施作業勞工個人暴露及作業環境區域採樣測定。勞工個人暴露測定以二支熱脫附不鏽鋼管分別填充吸附劑Tenax TA和Carbopack X，搭配分流管連接採樣幫浦，流量率設定為200 mL/min，以主動式採樣方式，實施全程單一樣本採樣。區域採樣測定以一個不鏽鋼瓶及二支熱脫附不鏽鋼管放置於製程區域定點，採集6小時的空氣樣本。所有熱脫附不鏽鋼管以熱脫附氣相層析儀分析，不鏽鋼瓶以氣相層析質譜儀分析，以估計勞工揮發性有機化合物的8小時時量加權平均暴露濃度和作業環境空氣濃度。本研究一共獲得552個暴露測定樣本，其中個人暴露測定樣本455個、氣體鋼瓶樣本50個及熱脫附管區域採樣樣本47個。結果顯示：每個工廠勞工所有揮發性有機化合物的8小時時量平均暴露測定濃度都遠低於法定的容許暴露濃度，即使以勞工所屬相似暴露群組暴露分佈的95%分位值(考量勞工暴露變異下)超過容許暴露濃度值的機率估計值，也均在可接受的5%暴露風險範圍內，因此勞工對這些揮發性有機化合物暴露符合法令規定。參與本研究的工廠，有些相似暴露群組因為所屬勞工數目較少，雖經過多次測定，但仍有不少群組暴露測定樣本數仍低於15，難以對其暴露變異有穩定的估計。因此各工廠需依照全面暴露評估策略的精神持續追蹤評估，以準確描繪每一個相似暴露群組的暴露實態。本研究測得的勞工暴露測定濃度遠低於現行標準採樣分析方法的偵測極限，為了獲得可靠的暴露測定數據，以執行良好的暴露評估，對於揮發性有機化合物的採樣測定及分析技術應該要提升。

關鍵字

石化廠 ； 揮發性有機化合物 ； 熱脫附 ； 暴露測定 ； 相似暴露群組

並列摘要

In this study six factories of a petrochemical industrial area were recruited for conducting workplace environmental monitoring. A comprehensive exposure assessment strategy was used to design and implement the environmental monitoring. Similar exposure groups (SEGs) were established in the written environmental monitoring plan for each factory. In each factory, both personal and area samples were taken for volatile organic compounds (VOCs) including benzene, toluene, xylene, ethylbenzene, n-hexane, tetrahydrofuran, n-butyl acetate, acetone, 1,2-dichlorethane, methyl isobutyl ketone, styrene, acrylonitrile and 1,3-butadiene. The personal exposure measurements were performed by using two stainless steel thermal desorption tubes packed with Tenax TA and Carbopack X sorbents respectively. The sampling pumps equipped with a dual port manifold were set up at a flow rate 200 mL/min to make active full-period single samples for the workers. The area air samples were taken by using a 6-liter canister and two thermal desorption tubes for 6 hours in an 8-hour workday. The thermal desorption tubes were analyzed by using thermal desorption gas chromatography and the canisters were analyzed by using gas chromatography mass spectrometry to estimate the 8-hour time-weighted average (8-hour TWA) exposure concentrations for the workers and the air concentrations of the work environments. A total of 552 samples including 455 personal exposure measurement samples, 30 canister samples and 47 area samples of thermal desorption tube samples. The results showed that all the 8-hour time-weighted average exposure concentrations of the VOCs were far below the permissible exposure limits. After taking account of exposure variability between workers, the probability of the 95th percentiles of exposure profile of all the SEGs exceeding the the permissible exposure limits was still in the 5% range of acceptable exposure risk. Therefore, the workers exposures to the VOCs were in compliance with regulatory standards. Some SEGs of the factories consisted of few workers. Althogh multiple exposure measurements were taken, these SEGs still had small sample sizes (less than 15) and could not obtian stable estimation of their exposure variability. According to the spirit of comprehensive exposure assessment strategy, continuous follow-up assessments were needed for the factories to accurately characterize the exposure profile of each SEG. The measured concentrations of the workers’ exposure to the VOCs were much lower than the detection limits of the currently recommended sampling and analytical methods by the government. To obtain reliable exposure measurement data and perform a sound exposure assessment, it is required to improve the techniques in the sampling and analytical of VOCs.

並列關鍵字

petrochemical factory ； volatile organic compounds ； thermal desorption ； exposure measurement ； similar exposure group

參考文獻

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