聊城市城区河湖水中Hg、As浓度分布特征及健康风险评价

为了解聊城市城区河湖水中Hg、As浓度分布,于2010年12月19日采集、分析了20个表层水样中Hg、As浓度,并采用美国环境保护署推荐的健康风险评价模型对其进行了初步评价.结果表明:城区河湖水中Hg、As的质量浓度分别为0.016～0.366、0.494～23.438 μg/L,各主要河湖水中Hg的平均浓度大小为周公河＞东昌湖＞小运河＞徒骇河；As的平均浓度大小为周公河＞徒骇河＞小运河＞东昌湖；东昌湖Hg浓度超过《地表水环境质量标准》(GB 3838-2002)的Ⅲ类水标准值,超标率为71.4％.各主要河湖水中Hg、As浓度的空间分布差异显著,Hg主要来源于大气沉降和沿岸生活污水的排放,As主要来源于工业废水,两者均受到上游来水的影响.As通过饮水途径产生的健康风险值在10-6～10-4 a-1,是Hg的103～106倍,高于部分机构推荐的最大可接受风险水平(1.0×10-6 a-1).建议有关部门应加强对聊城市城区河湖水中Hg、As的监测和环境风险管理.

Distribution characteristics and health risk assessment of Hg and As in the lake and rivers of Liaocheng urban area

20 surface water samples were collected in December 19,2010 to investigate the concentrations and distribution of mercury(Hg) and arsenic(As) in the lake and rivers of Liaocheng urban area.The USEPA recommended health risk assessment model was applied to primarily assess the health risk caused by Hg and As.The results showed that the concentration of Hg and As in urban lake and river were 0.016-0.366 and 0.494-23.438 μg/L respectively.The average concentration of Hg followed the order of Zhougong River>Dongchang Lake>Xiaoyun River>Tuhai River,the order for As was Zhougong River>Tuhai River>Xiaoyun River> Dongchang Lake.The Hg concentrations in Dongchang Lake exceeded the Ⅲ standard of surface water environmental quality(GB 3838-2002) with the unqualified rate of 71.4%.The spatial distribution characteristics of Hg and As presented great difference,generally,these pollutants might mainly come from atmospheric deposition,domestic and industry sewage and upper stream rivers.The risk levels of As were 10-6-10-4 a-1,which was 103-106 times of Hg.The risk values of As were higher than the maximum allowance levels(1.0×10-6 a-1).So,the suggestions were proposed to strengthen the monitoring and environmental risk management of Hg and As in the lake and rivers of urban area.