西江流域柳江水体重金属污染状况及健康风险评价

The Assessment of the Heavy Metal Pollution and Health Risks in the Liujiang River, Xijiang Region

关键词:  柳江  重金属  内梅罗指数  健康风险评价

Key words:  Liujiang River  heavy metals  Nemero index  health risks appraisal

摘要:

[目的]以广西柳江水体为研究对象,对柳江地表水体中Cu、Zn、Pb、Cd、As、Ni、Sb和Tl 8种重金属污染物含量进行分析测定,以阐明柳江水体重金属污染物的分布特征和风险水平。[方法]运用内梅罗综合指数法、健康风险评价模型对柳江水质等级和水体中重金属引起的健康风险水平进行评价。[结果]各采样点的重金属含量均符合地表水Ⅱ类水质标准,除点位S2为污染、点位S3为中污染外,柳江其余7个采样点水质均属重金属未污染状态,水质清洁。柳江所分析重金属的健康风险排序为As > Zn > Cd > Cu > Pb。所有采样点的健康风险值均低于国际辐射防护委员会推荐的最大可接受风险水平5.0×10^-5a^-1。[结论]柳州市内的冶炼及化工等外排废水,可能是导致柳江水体重金属含量升高的原因。As是柳江水环境产生健康风险的主要污染物质,应该作为柳江水环境风险管理的重点对象。

Abstract:

[Objective] The purpose of this research was to investigate the quality of the Liujiang River in Guangxi.Concentrations of heavy metals of Cu、Zn、Pb、Cd、As、Ni、Sb、Tl in the Longjiang River were analyzed to illustrate the distribution characteristics and risk levels of heavy metal pollutants in this area.[Methods] The Nemero comprehensive index method and the health risk assessment model were used to evaluate the grade of Liujiang River water quality and the health risk level caused by heavy metals in the water.[Results] The results demonstrated that the concentrations of heavy metals in each sampling point was in line with the surface water quality standard Ⅱ.Except that sampling site S2 was pollution and S3 was medium pollution, the water quality of the remaining 7 samples in Liujiang River was not polluted by heavy metals, and the water quality was clean.The health risk values of heavy metals As and Zn were higher than Cd, Pb, and Cu in the Liujiang River.The health risk values at all sampling points were below the maximum acceptable risk level (5.0×10^-5a^-1) recommended by the International Commission on Radiological Protection.[Conclusion] The smelting and chemical discharged waste water in Liuzhou city may be the cause of the increase of heavy metals in Liujiang water.Arsenic (As) is the main pollutant that causes health risks in Liujiang water environment, which should be the key target of Liujiang water environmental risk management.