The drinking water resource watershed of Wuling Mountain area and Qianjiang districts was studied from 2010 to 2014 through monthly water quality monitoring.In total,120 groups of valid data were obtained.The health risk assessments of 13 indicators (e.g.,Cd,As and Hg) were evaluated by the US EPA recommended health risk assessment model for water quality index.The results showed that the water quality of Xiaonan Hai and Dongtang Reservoir of Qianjiang district met the surface water environment quality standard Ⅲ (GB 3838-2002) from 2010 to 2014.The total carcinogenicity risk to adults of two drinking waters varied between 0.87 × 10-7 and 1.19 × 10-7,while the risk to children was 2.86 × 10-7 to 3.91 × 10-7.Both values were two magnitudes lower than the highest risk level accepted by the US EPA and ICRP (1 × 10-4 and 5 × 10-5).The rank of health risk was carcinogen ＞ non-carcinogen.The calculated health risk factors contribution rate indicated that more attention should be paid to control of hexavalent chromium for health risk,which was caused by drinking water exposure.The health risks to children of the two drinking water sources of Qianjiang district were more severe than to adults.Therefore,children were more vulnerable to chemical hazards.Uncertainty analysis indicated that the health risks of the evaluation results were credible;however,the level of health risks will be affected by changes in the pollutants concentration,unit weight average daily water consumption of human body and exposure time.%选择武陵山区域黔江区的2个城市集中式饮用水源地为研究对象,通过2010-2014年每月进行水质监测,获取120组有效数据,运用US EPA推荐的健康风险评价模型对13项水质指标(如Cd、As、Hg等)进行健康风险评估.结果表明:20102014年,黔江区小南海、洞塘水库监测指标均满足GB 3838-2002《地表水环境质量标准》Ⅲ标准,水质状况良好.2个饮用水源地的成人总致癌风险均在0.87×101～1.19×10-7 a-1之间,儿童总致癌风险均在2.86 ×1O-7～3.91 × 10-7a-1之间,成人和儿童的水质总健康风险均值低于US EPA和ICRP(1×10-4和5×10-5 a-1)的最大可接受风险水平2个数量级以上.健康风险排序为致癌物＞非致癌物.计算健康风险指标贡献率表明,通过饮水暴露途径引起健康风险应优先控制Cr6.黔江区2个城市饮用水源地对儿童产生的人体健康总风险值大于成人,因此儿童更易受到化学物质引起的健康危害.不确定分析结果表明,该研究健康风险评价结果具有可信性,但污染物浓度、人体单位体质量、日均饮水量以及暴露时间的变动将会影响健康风险水平的高低.
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