现行四氯乙烯职业卫生标准的环境影响评价

Environmental impact assessment on present occupational health standard of tetrachloroethylene

目的 对干洗剂四氯乙烯(TCE)的致癌性作出定性定量的评价,以预测干洗店从业人员的终生患癌危险度,并为研制合理的四氯乙烯卫生标准提供依据。方法 采用健康危险度评价的方法对四氯乙烯进行综合评价:①利用WHO权威文件中的动物实验资料及人类流行病学资料进行危害鉴定;②用致癌强度系数反映四氯乙烯致癌性的剂量反应关系;③在兰州市随机抽取24家干洗店,现场采样,用气相色谱法测定四氯乙烯的室内空气浓度,计算时间加权平均浓度(TWA),以估算个体暴露量;④结合以上三点,对干洗店从业人员的患癌超额危险度、超额病例数等作综合评定,并计算出可接受的室内空气浓度。结果 四氯乙烯是B2级致癌物,即可能人类致癌物,单位危险度为5.8×10-7μg/m3。干洗店内四氯乙烯的TWA为(46.45±5.08)mg/m3(标准状态),个体患癌超额危险度为2.69×10-2,年超额病例数为400,车间空气中可接受的TWA为36 mg/m3。结论现有标准是在四氯乙烯的一般毒性基础上建立的。对四氯乙烯污染状况进行调查后认为,其污染状况不容忽视,有必要在综合评价致癌性的基础上制定新的卫生标准,36 mg/m3是可行且有实用意义的。

Objective The carcinogenicity of tetrachloroethylene(TCE), a dry-cleaning solvent, was explored quantitatively and qualitatively in order to assess extra risk on dry-cleaning workers exposed to TCE and develop a much valid health standard. Methods The methods of health risk assessment were applied. Hazard assessment was carried out with experimental animal data and human epi-demiological data from WHO. Does-response relationship was reflected by carcinogen potency index(CPI). TCE time-weighed average (TWA) concentration of sample air, from 24 dry-cleaning shops taken randomly in Lanzhou, were measured with gas chromatography to estimate exposure levels, analyze risk characterization and calculate acceptable indoor TWA concentration of TCE. Results TCE TWA concentration in dry-cleaning shops was measured to be(46.45±5.08)mg/m3 under standard condition. TCE carcinogen potency index, estimated extra risk and annual extra number of case were 5.8×10-7μg/m3,2.69×10-2 and 400 respectively. The acceptable TWA concentration of TCE in workshop air was suggested to be 36 mg/m3 . Conclusion TCE is a probably carainogen to human. The pollution in dry-cleaning shops should not be ignored and the health standard should be reviewed. For the reason of environmental protection, an effective and safe substitute for TCE is urgently needed.