安徽北部矿区深层地下水重金属含量特征及水质评价

Study on content characteristics and water quality assessment of heavy metals in deep groundwater from northern Anhui mining areas

测试了安徽北部矿区4个典型煤矿深层地下水中5种重金属元素的含量,水样采自松散、煤系、太灰和奥灰4个含水层。在对各含水层5种重金属质量浓度特征分析的基础上,通过加附注评分法和Nemerow综合污染指数法对矿区主要含水层深层及区域整体开展了地下水重金属污染评价。结果表明:松散和太灰含水层中水样重金属质量浓度从高到低为Ni、Pb、Cu、Cd、Cr,而煤系和奥灰含水层中水样重金属质量浓度从高到低为Ni、Pb、Cu、Cr、Cd;整体地下水中重金属质量浓度从高到低为Ni、Pb、Cu、Cd、Cr;标准差显示煤系水和太灰水可能已受到采煤活动的扰动;松散层和奥灰水质为良好,太灰水质较差,煤系水质极差(F=7.52);整个矿区地下水水质分级为较差,综合污染评价结果为警戒线(NI=1.0),污染水平为尚清洁。

The given paper is aimed at presenting its investigation and analysis of the five kinds of heavy metals in the deep groundwater level from the four respective aquifers, that is, the unconsolidated formation layer, the coal-containing layers, the limestone aquifer of Taiyuan formation and the Ordovician limestone aquifer under monitoring activities in hoping to make an assessment of the pollution status in-situ by taking samples from the four typical coal mines in Anhui-north mining areas. When an analysis of the content characteristics of heavy metals was done with the conventional method and the Nemerow comprehensive pollution index method, we began to make an evaluation of the water quality by using the samples from the different aquifers, including the mixed aqua-strata. Our investigation in- dicates that the content of heavy metals in the groundwater from the unconsolidated formation and limestone aqua-strata accounts for the same descending order, that is, Ni 〉 Pb 〉 Cu 〉 Cd 〉 Cr, whereas the coal-bearing strata and the Ordovician limestone aqua-strata also take the same order, that is, Ni 〉 Pb 〉 Cu 〉 Cr 〉 Cd. Therefore, it can be inferred that the order of heavy metal content rates can be represented by the order of Ni 〉 Pb 〉 Cu 〉 Cd 〉 Cr in the whole area under investigation. Furthermore, the standard deviation implies that the change of the groundwater quality may also result from the mining activities. The entire pollution assessment by the conventional method proves that the most serious pollution rate to the water of the coalbearing series stands in F = 7.52. And the pollution situation with the other areas can be said relatively better in an order from the unconsolidated formation and Ordovician limestone aquifer, which are better than the limestone aquifer in Taiyuan formation. Taking the whole study area as an investigation object, it can be said that the pollution of its deep groundwater from all the aquifers is not so encouraging, with the whole deep groundwater of study area exactly being put on the warning level （NI = 1.0） when assessed by the comprehensive pollution evaluation. Thus, though its water quality can be said just OK on the whole for the time being, the given investigation helps to make clear the content characteristic features at the focus of the water quality assessment of heavy metal content rates in deep groundwater from the mining areas, which can provide a reference for the exploitation, utilization and protection of the water resources from the groundwater in the aforementioned mining areas.