環氧乙烷是一普通被各醫院所採用的消毒氣體，具有很強的烷基化能力且被認為是人體可能的致癌物。為暸解氣體消毒工作人員環氧乙烷曝露情形，本研究採立意取樣，選取北部4所醫院，以檢知管法檢測工作環境中環氧乙烷的瞬問曝露濃度，另外，長時間平均曝露濃度之監測則以美國職業安全衛生署OSHA-50之採樣方法採樣，以HP-5890氣相層析議分析。對曝露於此可能致癌物的氣體消毒工作人員，姊妹染色體交換（SCE）頻率是一極敏感的生物監測方法。醫院氣消工作場所的工作人員均納入為曝露組（41人）；另外，從各醫院選出49位在性別、年齡及抽煙習慣均與曝露組分佈相似的行政或資訊單位人員為比較組，比較兩組人員周邊淋巴球之SCE頻率。研究結果發現：氣消過程中，在移鍋時的環氧乙烷曝露濃度最高，有兩種消毒鍋機型其瞬間曝露濃度高達到50~60 ppm及大於100 ppm，而其他機型或工作項目之瞬間曝露濃度均小1 ppm。以個人採樣方法監測發現負責操作移鍋工作者，其15分鐘短時間暴露濃度（STEL），或4小時時平均暴露量（TWA）均高於其他工作人員，且隨醫院使用消毒鍋機型而有所差異。以環境採樣方法監測發現環氧乙烷因消毒鍋種類，有無獨立消毒房及通風設備是否良好尚有所差異。曝露組的SCE頻率與比較組（7.5 v.s. 7.7 SCEs/cell）並無差異。但抽煙者顯著高於不抽煙者（8.8 v.s. 7.6 SCEs/cell）。以迴歸模式，校正可能干擾因素亦得到相同結果。而以個人之工作月數及負責移鍋次數等曝露資料來探討曝露對SCE的效應，亦無發現劑量一效應關係。以高姊妹染色體交換頻率細胞方法對曝露但與比較組進行比較，兩組仍無差異。但以此方法比較抽煙者與非抽煙者，則發現兩者有顯著統計上的差異。

Ethylene Oxide (EtO) is widely used in hospitals for sterilization of heat-sensitive devices. EtO is an alkylating agent and binds irreversibly to DNA as an adduct. Sister chromatid exchange (SCE) has been found to be a very sensitive bio-monitoring method for alkylating agent exposure. Four hospitals in northern Taiwan were selected for study. The instantaneous EtO concentration, IS-minute sterilization, short-term and 4-hour time-weighted average (TWA) exposure levels were measured. The EtO concentration varied with the type of sterilizers and work practice. During sterilizers are opened for unloading, the instantaneous EtO concentration is as high as greater than is as high as 100 ppm and greater than 50-60 ppm. The instantaneous EtO concentrations were less than 1 ppm for all other work practices. The IS-minute short-term exposure levels (STEL) in two hospitals which used Castle 3240 sterilizers were high (24.7 ppm and 29.6 ppm) for unloading workers. The 4hr TWA was also higher than 1 ppm. However, the exposure levels in one hospital which used a Castle 3371 sterilizer manufactured after 1984 were much lower (15 minute STEL 0.5-1.0 ppm, 4-hr TWA ＜ 0.5 ppm). Excluding two with a history of cancer, 41 sanitary workers working in the sterilizing units of these four hospitals had blood samples taken for SCE analysis and were compared with a sex and smoking-statusmatched reference group comprised of 49 volunteers from administrative or computer units in the same hospital. The SCE frequency in the exposed group (7.5 SCEs/cell) was not different from that in the reference group (7.7 SCEs/cell). However, smokers had a higher SCE frequency than non-smokers (8.5 v.s. 7.6 SCEs/cell). The frequency of SCE was not different between hospitals and was not correlated with the duration of employment and the frequency of unloading. The percentage of high SCE frequency cells (HFC) was also not different between the exposed and reference groups, but HFCs were higher in smokers than in non-smokers.

環氧乙烷 ； 曝露濃度 ； 姊妹染色體交換

ethylene oxide, EtO concentration, sister chromatid exchange