拉萨河流域重金属污染及健康风险评价

在分析拉萨河水体重金属污染现状以及水质理化参数的基础上,对重金属含量进行Pearson相关性分析,并运用水环境健康风险评价模型对其进行了健康风险的初步评价.结果表明Cd、Pb、Cu、Mn、Ni和Zn未超过我国生活饮用水卫生标准（GB 5749—2006）的限值,As和Fe严重超标.8种重金属含量与pH值间均不存在显著相关性,其中Zn、Ni与Pb污染存在一定的同源性,而Ni与Cd来源不同,As、Mn、Fe、Cu之间污染具有多源性.污染物通过皮肤接触途径所造成的危害要远小于饮水途径,致癌物风险比非致癌物高2—8个数量级.其中As对总风险贡献率为99.60%,成为主要的风险污染物.拉萨河水体中污染物引起的总健康风险高于EPA推荐的标准值,具有显著的风险,应引起环境监测和环境管理部门的关注.

Pollution analysis and health risk assessment of heavy metals in Lhasa River

Partial correlation was analyzed based on the concentrations of heavy metals and water quality parameters of Lhasa River.Health risks associated with heavy metals in drinking water were assessed primarily by health risk assessment models.The results evaluated using the limit values of drinking water health standards in China(GB 5749—2006) showed that Cd,Pb,Cu,Mn,Ni and Zn did not exceed the limit,while As and Fe were severely over the limit.Correlation analyses demonstrated that there were stronger associations among Zn,Ni and Pb,and their good correlation suggested common sources.Ni and Cd were from different sources,and As,Mn,Fe and Cu had multiple pollution sources.The correlation between concentrations of the eight heavy metals and pH was not significant.Compared with ingestion exposure route,the harm caused by contaminants exposure through dermal contact route was far less.And carcinogenic risks by carcinogens were 2—8 orders of magnitude higher than non-carcinogens.As was the main risk pollutant,since its contribution to total risk was 99.60%.It is suggested that Lhasa River should be of concern by the environmental monitoring and management departments,since its total health risk was severely over the reference value recommended by USEPA.