基于umu遗传毒性效应的饮用水致癌风险评价的尝试

Carcinogen Risk Assessment of Drinking Water Based on Genotoxic Activities Using SOS/umu Test

化学物质暴露是导致癌症发生的重要诱因,通过饮用水暴露导致的人类致癌风险在饮用水处理技术中日益引起重视.由于水中化学物质种类繁多、组成复杂,准确地检测每个致癌物质的浓度和毒性非常困难.为了控制饮用水的安全,根据DNA损伤诱导SOS反应而表达umuC基因这一基本原理建立的SOS/umu测试法,已经广泛应用于饮用水遗传毒性的检测.论文建立了基于umu遗传毒性效应的饮用水致癌风险评价方法,并对北方某水厂饮用水的遗传毒性进行了umu测试,计算了该地区饮用水的致癌风险,提出了可能的饮用水遗传毒性基准值.结果表明,该水厂常规工艺出水的致癌风险均值为1.55×10-6,存在一定的安全隐患;而深度处理工艺能有效地削减出水致癌风险均值至5.3×10-7,达到目前先进国家水质管理的要求,保障了饮用水的安全.样品中4-硝基喹啉-1-氧化物(4-NQO)的等当量浓度(TEQ4-NQO)0.0948μg·L-1可作为饮用水遗传毒性基准值。

Exposure to chemicals is an important inducing factor of cancer. The carcinogen risk on human induced by exposure to drinking water has caused great concern among scientists and policy decision makers in developing drinking water treatment technologies. However, it is difficult to actually determine the concentration and toxicity of all carcinogenic chemicals due to limitation of instrumental analytical method. To guarantee the security of drinking water, a SOS/umu test, which is based on alterations in the induction of SOS response as a consequence of DNA damage, has been established and widely used for detecting genotoxicity of drinking water. In this paper, a method for carcinogen risk assessment of drinking water based on genotoxic activities using SOS/umu test was developed, and then it was applied to assess the carcinogen risk of drinking water from a waterworks in Noah China. We also proposed a safe benchmark of genotoxicity for drinking water corresponding to 10-6 carcinogen risk. The average carcinogen risk of drinking water treated by a conventional treatment process was 1.55×10^-6, while it could be controlled to 5.3×10^-7 by advanced treatment processes, indicating that the advanced treatment processes can successfully guarantee the safety of drinking water. We proposed adopting 0.0948μg·L^-1 toxicity equivalent quantity of 4-nitroquinoline-1-oxide （4-NQO） as a safe benchmark of genotoxicity for drinking water.