典型矿区深层地下水重金属含量特征及健康风险评价——以皖北矿区为例

Health Risk Assessment of Heavy Metals in Deep Groundwater from Different Aquifers of a Typical Coal Mining Area:A Case Study of a Coal Mining Area in Northern Anhui Province

以皖北矿区为例,分析测试了不同含水层（松散、煤系、太灰、奥灰）中的6种重金属元素（Cd、Cr、Cu、Zn、Pb、Ni）,对其含量特征及健康风险评价进行了研究。结果表明,6种重金属在不同含水层含量大小次序各不一样,从整体来看,研究区地下水中所测重金属含量依次为Ni〉Zn〉Pb〉Cu〉Cd〉Cr,与太灰水一致;整体地下水中Cr、Cu和Zn均未超过（GB/T14848—93）中Ⅲ类水质标准,Cd、Pb和Ni有部分水样超过标准限值。化学致癌物Cd和Cr在各含水层所致健康危害风险值数量级在10-6-10^-4 a^-1,Cr健康风险值在各含水层中均大于Cd,Cr在煤系含水层危害风险值（1.29×10^-4 a^-1）已超过美国环境保护局（USEPA）最大可接受风险（1×10^-4 a^-1）,为研究区首要的环境健康风险管理控制指标。化学非致癌物Cu、Zn、Pb、Ni四种重金属健康危害风险值较小,数量级在10^-11-10^-8a^-1,Pb和Ni健康危害风险值相对较高,也应引起重视。各含水层总的健康风险值大小次序为：煤系〉太灰〉奥灰〉松散,前三者已超过国际辐射防护委员会（ICRP）推荐的（5×10^-5 a^-1）最大可接受风险,其中煤系含水层总的健康风险值为1.46×10^-4 a^-1,已超过USEPA（1×10^-4 a^-1）推荐的最大可接受风险。对矿区深层地下水开展重金属含量分析和健康风险评价,可为地下水水资源的开采利用和保护提供参考。

Six heavy metals（Cd,Cr,Cu,Zn,Pb and Ni）in deep groundwater from four aquifers（unconsolidated formation,coal-bearing series,limestone water in Taiyuan Formation and Ordovician limestone water） were monitored in a coal mining area of northern Anhui Province,and their content characteristics and health risk assessment were analyzed. The research result shows that the content orders of heavy metals from the four aquifers were different from each other. In the whole study area,the order of heavy metals content is the same as that of the groundwater samples from limestone water in Taiyuan Formation aquifer,with the order being Ni〉Zn〉Pb〉Cu〉Cd〉Cr. A comparison with China＇s quality standard for groundwater（GB/T14848—93 Ⅲ）shows that the concentrations of Cr,Cu and Zn are below GB/T14848—93 Ⅲ,while the concentrations of Cd,Pb and Ni in some groundwater samples exceed the standard values. The health risk of chemical carcinogens is around 10-6-10-4 a-1,and the value of Cr is higher than that of Cd in the four aquifers. The highest mean health risk（1.29×10^-4 a^-1） of Cr was observed in the aquifer of coal-bearing series,which has exceeded the maximum allowance levels recommended by USEPA（1×10^-4 a^-1）,and it is the primary control target for environmental health risk management; the health risks of chemical non-carcinogens of four heavy metals（Cu,Zn,Pb,Ni）are around 10^-11-10^-8 a^-1,and their health risk values remain within the acceptable range. The health risks of Pb and Ni are much higher,and should be taken seriously. The total health risks of four aquifers were found in order of coal-bearing serieslimestone water in Taiyuan FormationOrdovician limestone waterunconsolidated formation; the first three have exceeded the maximum allowance levels recommended by ICRP（5×10^-5 a^-1）,and the highest total health risk（1.46×10^-4 a^-1） was observed in the coal-bearing series aquifer,which has exceeded the maximum allowance levels recommended by USEPA（1×10^-4 a^-1）. The study of content characteristics and health risk assessment of heavy metals in deep groundwater from coal mining areas can provide references for exploitation,utilization and protection of groundwater resources.