柳江流域饮用水源地重金属污染与健康风险评价

为说明柳江流域饮用水源地的重金属元素含量特征及饮用水水质对人体健康的潜在危害，于2016年1~12月对柳江干流及主要支流的水体进行常规水质指标和Cd、As、Cr、Hg、Zn、Cu、Pb、Fe、Mn等金属元素进行分析检测，并采用美国EPA推荐使用的健康风险评价模型对饮用水源地的健康风险进行评价.结果表明，Cd、As、Cr、Zn、Cu、Pb、Fe、Mn含量未超过我国地表水环境质量标准（GB 3838-2002）的限值，Hg含量存在超标.对重金属含量进行Pearson相关性分析，其中Cd、Pb、As与Fe可能具有相似的来源，Cu、Cr、Hg、Zn之间污染具有多源性，9种重金属含量与pH值间均不存在显著相关性.柳江流域饮用水源地致癌重金属元素健康风险成人和儿童分别为4.52E-04 a^-1和5.91E-04 a^-1，非致癌健康风险成人和儿童分别为8.96E-09 a^-1和1.14E-08 a^-1.致癌重金属Cr、As、Cd通过饮水途径所造成的人均年健康风险分别表现为Cr > As > Cd，风险值范围为3.58E-06~1.21E-04 a^-1，Cr和As的风险值大于ICRP所推荐的风险水平5.0×10^-5 a^-1.该研究区内重金属元素非致癌健康风险值范围为3.53E-12~2.87E-09 a^-1，均在EPA推荐的可接受水平内，初步认为不会对人体健康产生明显危害.流域主要健康风险来源于致癌物.Cr和As是柳江流域水环境产生健康风险的主要污染物，应当优先列为柳江流域水环境风险管理的主要对象.

Heavy Metal Pollution of the Drinking Water Sources in the Liujiang River Basin, and Related Health Risk Assessments

The characteristics of heavy metal pollution in drinking water in the Liujiang river basin and its potential hazards on human health were investigated. In this study, the regular water-quality indices and the contents of metal elements Cd, As, Cr, Hg, Zn, Cu, Pb, Fe, and Mn in the Liujiang river and its main tributaries were detected from January to December of 2016. The health risks of drinking contaminated water were evaluated by the health risk assessment model recommended by the US EPA. The results showed that the concentrations of all of the aforementioned metal elements, except Hg, did not exceed the limits recommended by China''s surface water environmental quality standard (GB 3838-2002). Pearson correlation analysis of the concentrations of metal elements indicated that Cd, Pb, As, and Fe may have similar sources, and Cu, Cr, Hg, and Zn may have source of diversity, while there was no significant correlation between the concentrations of metal elements and the pH value. The carcinogenic health risks posed by heavy metal elements in the Liujiang river basin in adults and children were 4.52E-04 a^-1 and 5.91E-04 a^-1, respectively, while the non-carcinogenic health risks were 8.96E-09 a^-1 and 1.14E-08 a^-1, respectively. The heavy metal elements in drinking water, on the basis of their average carcinogenic health risks, were ranked as Cr > As > Cd, and the risk levels ranged from 3.58E-06 to 1.21E-04 a^-1; the risk values of Cr and As were higher than the maximum allowance levels recommended by ICRP (5.0×10^-5 a^-1). Simultaneously, the risk levels of the average non-carcinogenic health risks ranged from 3.53E-12 to 2.87E-09 a^-1, and the range was lower than the maximum allowance levels recommended by EPA. Carcinogens, especially Cr and As, are the main causes of health risks in the aquatic environment of the Liujiang river basin, and should be prioritized as the main objects of aquatic environmental risk management in the Liujiang river basin.