湘江流域水体重金属污染及健康风险评价

Heavy Metal Pollution and Health Risk Assessment in Xiangjiang River Basin

为研究湘江流域水体重金属污染水平及对人体健康的危害,选取2000—2016年全流域26个监测站点,分析了Hg、Zn、Cu、As、Cr^(6+)、Pb、Cd共7种重金属时空分布特征,利用综合污染指数评价法分析重金属的污染水平,并采用美国环保局推荐的健康风险评价模型对健康风险作了初步评价。结果表明:时间上,基于综合污染指数法及MK趋势分析可知流域水质状况良好且逐年改善;空间上,流域水质上游较中下游好,重金属高浓度值主要分布在中下游。健康风险评价结果表明:流域致癌重金属平均个人健康风险值表现为As>Cr^(6+)>Cd,非致癌物重金属平均个人健康风险值表现为Pb>Cu>Zn>Hg,流域主要受致癌物风险影响。As、Cr^(6+)是产生水体健康风险的主要来源且儿童受到的健康风险远高于成人。

To study the level of heavy metal pollution in the Xiangjiang River Basin and its harm to human health,this paper selected the data from 26 monitoring stations in the whole basin from 2000 to 2016 and analyzed the temporal and spatial distribution characteristics of 7 heavy metals including Hg,Zn,Cu,As,Cr^(6+),Pb,and Cd.The pollution levels of these heavy metals were analyzed by the comprehensive pollution index evaluation method,and the health risk was preliminarily evaluated using the health risk evaluation model recommended by the US Environmental Protection Agency.Temporally,depending on the results of the comprehensive pollution index method and Mann-Kendall(MK)trend analysis,the water quality of the basin is in good condition and is improving year by year.Spatially,water quality in the upper reaches of the basin is better than that in the middle and lower reaches,and the high concentrations of heavy metals are mainly distributed in the middle and lower reaches.The health risk assessment results show that the average personal health risks of carcinogenic heavy metals in the basin are in the order of As>Cr^(6+)>Cd,and the order of Pb>Cu>Zn>Hg is summed up for those of non-carcinogenic heavy metals.The basin is mainly affected by the risks of carcinogens.As and Cr^(6+)are the main sources of water health risks,and the health risks to children are much higher than to adults.