贵阳市西郊水厂所供管网末梢水重金属污染物季节性特征及潜在健康风险评价

The Seasonal Characteristics and Potential Health Risk Assessment on Heavy Metal Pollution in Terminal Tap Water from Guiyang Western Suburbs Water Plant

以贵阳市西郊水厂2014年3月和7月所供管网末梢水中10种重金属污染物检测数据为基础,进行了季节性特征分析,并采用美国环保局（USEPA）推荐的健康风险评价模型进行了潜在健康风险评价。结果表明,贵阳市西郊水厂所供管网末梢水中10种重金属的浓度均符合国家饮用水卫生标准;重金属污染物的浓度随季节呈现出不同的特征,汞、锌、硒、钼和钡5种重金属的平均浓度呈现枯水期高于丰水期的特征,而铅、铜、锰和镍4种重金属正好相反,砷浓度的季节性特征不显著;成年人的年平均致癌风险显著大于儿童,但两者年平均非致癌风险接近;儿童和成年人2类人群经口暴露途径的健康风险值均大于皮肤暴露,其中致癌风险分别在2.49×10-6-9.16×10-6和3.26×10-8-9.59×10-8之间,非致癌风险在2.29×10-8-3.20×10-8和1.85×10-10-4.14×10-10之间,且致癌风险均大于非致癌风险。贵阳市西郊水厂所供管网末梢水中10种重金属污染物致癌风险和非致癌风险均未超过最大可接受水平,未对该供水区居民的健康造成威胁。

The seasonal characteristics of the 10 heavy metals were studied in terminal tap water from Guiyang Western Suburbs Water Plant, based on the data of water quality collected on March and July, 2014. The potential risk to human health was assessed by the model which is recommended by the U.S. Environmental Protection Agency （USEPA）. The results showed that the concentration of 10 heavy metals satisfies the national sanitary standard for drinking water. The concentration of heavy metal pollutants demonstrated different characteristics with various seasons. The average concentration of Hg, Zn, Se, Mo and Ba in dry season was higher than wet season, and Pb, Cu, Mn and Ni showed higher average concentration in wet season. No obvious concentration change was observed for As. The average carcinogenic risk for adults were obviously greater than for minors, but the non-carcinogenic and minors via dietary intake were higher than the risk was almost the same. The health risk for both adults way via dermal intake, and the carcinogenic risk was greater than the non-carcinogenic risk. The indexes of risk were 2A9 ×10-6 -9.16 × 10-6 to 3.26 × 10-8 ×9.59 × 10-8, and 2.29 × 10.8 - 3.20 × 104 to 1.85 × 10-10 - 4.14 × 10-10, respectively. In conclusion, the carcinogenic risk and the non-carcinogenic risk of 10 heavy metals in terminal tap water, supplied by Guiyang Western Suburbs Water Plant, were lower than the maximum allowance levels, which would not cause health hazard to human beings in the supply area.