鉻電鍍勞工含六價鉻之可吸入性氣膠暴露與生物偵測

Inhalable Cr+6-Bearing Aerosol Exposure and Biological Monitoring of Chromium-Electroplating Workers

本研究主要目的為藉個人可吸入性氣膠採樣與生物偵測，以評估六價鉻電鍍業作業勞工之暴露情形。另本研究亦嘗試藉由個人暴露濃度與生物偵測結果間之比較，以建立與健康有關之含鉻氣膠之容許暴露濃度標準。本研究採樣對象為本省南部6 家電鍍廠中67 位勞工。研究中係以IOM 個人可吸入性氣膠採樣器與呼吸性氣膠旋風分離器以評估勞工之個人暴露情形。在生物偵測方面，本研究則收集勞工每週工作結束前之尿液進行分析。研究結果發現勞工個人可吸入性含鉻氣膠之暴露（Cinh），低於現今之TLV-TWA 值（即50 μg/m3）。唯若與瑞典之PELTWA（即20 μg/m3）標準相比較，則有4 名超過標準；另就生物偵測之尿中鉻濃度（Curine）而言，計有6 樣本測值高於BEI 值（即30 μg/g·creatinine）。線性迴歸分析結果發現：Curine＝1.84Cinh－0.14（R2＝0.77），顯示勞工個人暴露對生物偵測值具有良好之預測能力。本研究亦同時發現勞工之Cinh 與呼吸性含鉻氣膠暴露（Cresp）之關係為：Cinh＝1.28Cresp（R2＝0.94），因此可推知所採樣之電鍍廠可能存在相似的氣膠粒徑分布。在假設尿中鉻濃度與BEI 值均同為30 μg/g·creatinine之情形下，可知相對應之可吸入性鉻容許暴露濃度之推估值為16 μg/m3，而呼吸性鉻容許暴露濃度則為13 μg/m3。雖然本研究所獲致可吸入性鉻容許濃度較TLV-TWA 低，但與現今瑞典之PEL-TWA 則十分接近。

The purpose of this study is to assess the Cr+6 exposures of workers in the electroplating industry by using both personal inhalable aerosol sampling and biological monitoring techniques. In addition, comparisons are made between personal exposure concentrations and biological monitoring results in order to develop a new health-related exposure limit for Cr+6-bearing aerosols. 67 workers from 6 electroplating plants located in southern Taiwan were included in this study. Both IOM personal inhalable aerosol sampler and respirable cyclone sampler were used to evaluate workers’ exposures. For conducting biological monitoring, the spot urine of each worker was collected at the end of the last shift of the workweek. The results show all personal inhalable exposures are well below the current TLV-TWA value of 50 μg/m3, but four personal exposure levels are found higher than the PELTWA value of 20 μg/m3 as set in Sweden. For biological monitoring results, six workers are found with urinary Cr concentration higher than current Biological Exposure Index (BEI) value (30 μg/g·creatinine). The linear regression results show Curine=1.84Cinh+0.14 (R2=0.77), which indicates that biological monitoring results can be effectively predicted by using personal exposures. This study also shows that Cinh=1.28Cresp (R2=0.94), which indicates particle size distributions occurred at all selected electroplating plants might be similar. On the condition that Curine is equivalent to the BEI value of 30 μg/g·creatinine, the corresponding permissible exposure limits for inhalable and respirable Cr+6 are found to be 16 μg/m3 and 13μg/m3 respectively. Although the resulting permissible exposure limit for inhalable Cr+6 is significantly lower than the current value of TLV-TWA (50 μg/m3), it is close to the value of PEL-TWA (20 μg/m3) currently promulgated by Sweden.