2014年杭州市主城区饮用水中消毒副产物的分布及其健康风险
Distribution and Health Risk of Disinfection By-Products in Drinking Water in Hangzhou Main Urban Zone, 2014
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摘要:
目的 了解杭州市主城区饮用水中消毒副产物的种类、分布水平，并对其健康风险进行评价。
方法 根据生活饮用水标准检验方法（GB/T 5750-2006）的要求，于2014年丰水期（5月、8月）、枯水期（1月、11月）对杭州市主城区内5家市政水厂的出厂水和相应的5个末梢水点进行水样采集，共采集水样40份；并对水样中13种消毒副产物的质量浓度水平及与消毒副产物产生相关的理化指标进行检测。参照美国环保局的致癌风险模型，评价消毒副产物通过饮水途径对杭州市人群所引起的健康风险。
结果 杭州市主城区饮用水中主要检测到的消毒副产物为三卤甲烷类物质（三氯甲烷、二溴一氯甲烷、二氯一溴甲烷），其在出厂水和末梢水中的检出质量浓度分别为0.7～51.7、2.1～27.9 μg/L。消毒副产物浓度在不同季节分布无差异（均
P >0.05），与水温、pH值、游离余氯水平无关，但与出厂水中氨氮的浓度相关性较强（相关系数范围0.448～0.643）。出厂水和末梢水中消毒副产物引起的致癌风险为3.00×10-6～6.25×10-5和4.17×10-6～3.69×10-5；非致癌健康风险为3.45×10-3～6.72×10-2和4.39×10-3～3.38×10-2。致癌风险均来自三卤甲烷类物质，其中又以二溴一氯甲烷、二氯一溴甲烷为主；而5种消毒副产物对非致癌健康风险的贡献率相当。结论 三卤甲烷为2014年杭州市主城区饮用水中主要的消毒副产物。消毒副产物所引起的潜在致癌风险、非致癌健康风险均在美国环保局标准的限值内。
Abstract:Objective To understand the kinds and distribution levels of disinfection by-products (DBPs) and their potential health hazards in drinking water in Hangzhou main urban zone.
Methods According to the
Drinking Water Standard Inspection Method (GB/T 5750-2006), in wet season (May and August) and dry season (January and November) of 2014, the concentrations of 13 DBPs and relevant physical and chemical indices were determined in 40 water samples from five centralized water supply systems and five households (finished water and tap water) in Hangzhou main urban zone. The health risks of DBPs via drinking water were assessed based on the cancer risk assessment model recommended by U.S. Environmental Protection Agency (EPA).Results Trihalomethanes (THMs)i.e. trichloromethane (TCM), chlorodibromomethane (BDCM), and dichlorobromomethane (DBCM) were the principal DBPs in drinking water in Hangzhou main urban zone, and the concentrations in finished water and tap water were 0.7-51.7 μg/L and 2.1-27.9 μg/L respectively. The concentrations showed no seasonal variation (all
Ps >0.05) and were not associated with water temperature, pH, and residual chlorine levels, but a strong correlation with the concentration of ammonia nitrogen in finished water was found (correlation coefficient, 0.448-0.643). In addition, the values of carcinogenic risk for DBPs in finished water and in tap water were 3.00×10-6-6.25×10-5 and 4.17×10-6-3.69×10-5 respectively; the values of non-carcinogenic risk were 3.45×10-3-6.72×10-2 and 4.39×10-3-3.38×10-2 respectively. Carcinogenic risks were all contributed by THMs, and BDCM and DBCM were the main contributors; but for non-carcinogenic risks, the five kinds of DBPs had almost equivalent contributions.Conclusion THMs are the principal DBPs detected in the drinking water in Hangzhou main urban zone in 2014. Both the potential carcinogenic and non-carcinogenic health risks induced by DBPs through drinking water are within the limits recommended by U.S. EPA.
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