佛山市某城区饮用水重金属健康危害风险初步评估

目的监测佛山市某城区饮用水中重金属含量并评价其健康风险。方法在佛山市某城区选择3间水厂作为监测对象，在选择水厂的供水范围内选定5～6个监测点，分枯水期（2010年4月）、丰水期（2010年11月）各1次采集水样，检测砷、锑、镉、铬（六价）、铍、铅、汞、硒、镍、铊、铝、铁、锰、铜、锌共15种重金属元素含量，按《生活饮用水卫生标准》GB5749--2006进行评价，并采用美国环境保护署健康风险评价模型分别评价其致癌风险与非致癌风险。结果全年共监测11份饮用水水样，11份水样中除铍未检出外，其余14种金属元素均有检出，含量年均值在1．42×10^-5-8．00×10^-2mg／L之间，均符合国家生活饮用水卫生标准；铬（六价）、砷、镉3种金属元素风险值分别为3．50×10^-5a^-1、1．14×10^-5a^-1、1．59×10^-5a^-1，总致癌风险为4．66×10^-5a^-1；除铍、铁外，其余13种金属污染物经饮水途径暴露所致年均非致癌风险值在3．97×10^-12a^-1～9，26×10^-8a^-1，非致癌风险总和为1．41×10^-7a^-1，各金属年均风险指数除铝、锌分别为6．76、2．82外，其余均〈1。结论佛山市某城区饮用水中重金属含量符合生活饮用水卫生标准要求，部分重金属年均致癌风险值接近国际辐射防护委员会推荐最大可接受水平，存在一定健康风险，而被测的重金属年均非致癌风险相对较小，提示重金属风险管理应以致癌风险为主。

Health risk assessment of heavy metals in drinking water in a certain district of Foshan City

Objective To monitor the levels of heavy metals in drinking water in a certain district of Foshan and evaluate the health risks. Methods Five or six urban drinking water monitoring points were selected from three waterworks in a district in Foshan. Drinking water samples were collected from above points in April and November 2010, respectively, to test the contents of heavy metals including arsenic, antimony, cadmium, chromium （VI）, beryllium, lead, mercury, selenium, nickel, thallium, aluminum, iron, manganese, copper, and zinc. The contents were evaluated according to the Standard for Drinking Water Quality （ GB 5749 -2006） and calculated for cancer risk and hazard index according to health risk assessment models recommended by the United States Environmental Protection Agency （US EPA ）. Re- suits In all 11 water samples, 14 heavy metals except beryllium were detected out, but their contents were from 1.42×10^-5 to 8.00×10^-2mg/L, lower than the value of Standard for Drinking Water Quality （ GB 5749 - 2006 ）. Total and particular carcinogenic risk of chromium （ VI）, arsenic, and cadmium were 4.66×10^-5a^-1, 3.50×10^-5a^-1、1.14×10^-5a^-1、1.59×10^-5a^-1, respectively. In 13 heavy metals except beryllium and iron, total noncarcinogenie risk was 1.41 ×10^-7 a i and particular non- carcinogenic risks were from 3.97 ×10^-12 a^-1 to 9.26 ×10^-5. The hazard indices （HI） of aluminum and zinc were 6.76 and 2.82, respectively, while the HI of other heavy metals were lower than 1. Conclusion The contents of heavy metals in drinking water in a certain district in Foshan met the Standard for Drinking Water Quality, but there has been a certain health risk due to the annual average integrated carcinogen-ic risk of particular heavy metals approaching to the nmximum acceptable level recommended by the Inter- national Commission on Radiological Protection （ICRP）. Compared with carcinogenic risk, the annual av- erage noncarcinogenic risk of detected heavy metals was lower too. It indicated that carcinogenic risk should be consider as priority in risk management of heavy metals.