以全面性暴露評估策略進行職業暴露管理問題之探討

Exploration of Issues Relevant to Occupational Exposure Management with Application of Comprehensive Exposure Assessment Strategy

謝憲順(Hsien-Shun Hsieh)

指導教授 ： 吳俊德

長榮大學/健康科學學院/職業安全與衛生研究所/碩士(2009年)

https://doi.org/10.6833/CJCU.2009.00005

摘要

國內事業單位依法令規定持續執行有害物質作業環境採樣測定，針對測定獲取的暴露資料，是否執行暴露評估並修正其採樣策略，以建立作業勞工有害物質暴露實態(exposure profile)值得探討。本研究以一個曾參與推動全面性暴露評估策略的事業單位，審視過去的作業環境測定計畫及暴露測定數據，評估下列項目：(1)事業單位是否落實執行該述策略; (2)執行數據處理與統計分析; (3)比較不同年代的環測數據所建構的相似暴露群組(similar exposure groups, SEGs)的暴露實態; (4)事業單位是否依暴露評估結果修正及調整SEGs，建構符合實況的作業勞工暴露實態。結果顯示：事業單位安全衛生人員對於環境測定資料，僅限於與職業暴露限值做比較，仍未有效地用於執行暴露評估目的。該單位勞工從事電焊作業所遭受的金屬燻煙暴露，作業環境測定計畫僅實施總粉塵與鐵測定，而本研究收集的金屬燻煙暴露測定發現：可吸入性粉塵中鐵、鉻、鎳和鉛四種金屬暴露，大多高於1/2 ACGIH TLVs，顯見電焊作業中重金屬暴露重要性甚於厭惡性粉塵；而比較不同勞工可吸入性鐵測定數據中，其暴露差異範圍可達2.8~11.4倍，且該廠有機溶劑作業勞工二甲苯8小時時量平均暴露值為56.28 ppm已高於NIOSH與ACGIH限值的1/2，而高暴露群組均與作業項目、地點與通風設施是否固定有顯著相關。另製程潛在的化學暴露危害，即使針對訂有容許濃度的物質，亦因危害資訊蒐集不夠詳確、規劃及執行環測人員專業素養不足、管理不當等因素，即使執行環測多年後，仍有許多暴露危害尚待評估確認。而原策略中作業勞工劃分9個SEG，經評估後至少可再細分至25個SEG(含4個可調整循環檢測群組)，但在該作業環境測定計畫中SEG的分組卻未曾修改，顯示事業單位執行全面性暴露評估策略的精神未能真正落實。依法令規定，環測資料需保存3年、健檢資料與相關紀錄需留存10年，已不符合建構勞工暴露實態的要求。如何以電腦檔案管理作業環境測定數據，有效地分析整理統計這些數據，讓它們發揮該有的效益，應該正視。過去所推動的全面性暴露評估策略在事業單位如何持續改善，是作業環境測定制度上應加以強調的課題。

關鍵字

作業環境測定、相似暴露群組、暴露評估、暴露管理

並列摘要

Enterprises perform workplace environmental monitoring to toxic agents as required by law. However, it is not clear whether the exposure data obtained from the environmental monitoring are used to conduct an exposure assessment for workers, to correct the strategy of exposure sampling, as well as to establish exposure profiles of workers. In this study the workplace environmental monitoring plan and measurement data of an enterprise which participated in the project of comprehensive exposure assessment proposed by government was examined and evaluated for the following items: (1) to examine whether the enterprise complied with the monitoring plan; (2) to conduct exposure data analysis and statistical analyses; (3) to compare the exposure profile of similar exposure groups (SEGs) constructed from the monitoring data in different years; (4) to confirm whether the enterprise used the results of exposure assessment for correcting and adjusting SEGs and constructed the representative exposure profiles of the current SEGs. The results of this study showed that the personnel of occupational safety and health of the enterprise only used the exposure monitoring data for the comparison with the occupational exposure limit of each exposure agent. They did not utilize the exposure data for the purpose of exposure assessment. The workers in the welding processes of the enterprise were exposed to metal fume. However, the exposure measurements of total dust and iron were considered in the environment monitoring plan of the enterprise. The new exposure measurements of metal fume collected in this study showed that the exposure to iron, chromium, nickel and lead of inhalable dust was higher than one-half of its ACGIH TLV, respectively. This indicated that the importance of metal exposure for the welding workers was higher than that of nuisance dust exposure. The range of iron exposure in inhalable dust for the workers in different SEGs varied between 2.8 and 11.4 times. The 8-hour time-weighted exposure concentration of toluene for the solvent handling workers was 56.28 ppm which exceeded one-half of the occupational exposure limits of NIOSH and ACGIH. The SEGs with high exposure were significantly related to the immobility of work tasks and locations and the installation of ventilation system. Because of the lack of hazard information, the knowledge of designing and conducting environmental monitoring, as well as inappropraite exposure management, etc., the potential exposure to chemicals from the processes were still needed to have more evaluations on the magnitude of hazards. In the original strategy of environmental monitoring the workers were classified into 9 SEGs, but the SEGs has not been changed for many years. In this study it was found that at least 25 SEGs including 4 SEGs for periodic exposure monitoring were required to characterize the workers’ exposures. This illustrated that the essence of the comprehensive exposure assessment strategy was not really implemented in the enterprise. According to relevant regulations, the data of environmental monitoring and the results of personnel health surveillance are needed to keep for 3 and 10 years, respectively. However, these regulations didn’t meet the requirement of constructing exposure profiles of workers’ exposures. It should be emphasized that how to use a computer and database program manages exposure data and performs statistical analyses. The system of environmental monitoring based on comprehensive exposure assessment strategy should focus on the issue of continuous improvements on exposure characterization for the workers in an enterprise.

並列關鍵字

exposure assessment strategy, similar exposure group, work environment monitoring

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