酸性矿山排水影响的水库沉积物微量元素地球化学特征

为了解酸性矿山排水（AMD）影响下水库沉积物中微量元素的质量分数水平及其分布特征，对常年受酸性废水影响的贵州兴仁猫石头水库沉积物中26种微量元素的质量分数、相关性及控制因素进行了分析。结果表明：猫石头水库沉积物柱中Sr、Ba、Zr、V、Cr和As质量分数平均值超过了100 μg/g，其中As质量分数最高，平均值超过800 μg/g；Be、Ta、Co、Ag、Cd、Sn和Se质量分数的平均值都在5 μg/g以下；其他元素质量分数平均值则在10~60 μg/g之间。相较未受AMD影响的水系沉积物，研究区水库沉积物具有明显的As和Sb富集特征。水库沉积物中Li、Be、Rb、Sr、Cs、Ba、Sc、Y、Zr、Hf、Nb、Ta、Th之间存在显著正相关关系，而As与这些元素之间存在显著负相关关系。元素相关分析、因子分析及微量元素图解表明，Li、Be、Rb、Sr、Cs、Ba、Sc、Y、Zr、Hf、Nb、Ta、Th、Cr、Sb等元素受控于流域岩石化学风化和土壤物理侵蚀，这也是控制研究区元素分布最重要的因素，而Cu、Cd等重金属元素则与AMD对地层中元素的溶蚀析出和有机质等细颗粒物的吸附有关。另外，研究区重金属元素中，Cd、Cu、Pb、Cr、Zn的生态风险轻微，而As和Sb则具有很强的潜在生态风险。

Trace Elements Geochemical Characteristics of Reservoir Sediments Affected by Acid Mine Drainage

In order to understand the content and distribution characteristics of trace elements in reservoir sediments under the influence of acid mine drainage(AMD),the concentration and distribution of twenty-six trace elements were analyzed in the sediment cores from Maoshitou Reservoir and its inflow tributaries in Guizhou Province, Southwest China. The results show that the mean contents of Sr, Ba, Zr, V, Cr and As in the sediment cores are higher than 100 μg/g, and the content of As is the highest, the average content exceeds 800 μg/g; while the mean values of Be, Ta, Co, Ag are lower than 5 μg/g, the values of other elements lie in the range of 10 and 60 μg/g. Compared with the stream sediments without affected by AMD, the reservoir sediments in the study area are obviously rich in As and Sb. There are obvious positive correlations between Li, Be, Rb, Sr, Cs, Ba, Sc, Y, Zr, Hf, Nb, Ta,and Th in reservoir sediments, and their distribution is basically similar, while there is a significant negative correlation between As and these elements. Element correlation analysis, factor analysis,and trace element diagrams show that Li, Be, Rb, Sr, Cs, Ba, Sc, Y, Zr, Hf, Nb, Ta, Th, Cr,and Sb etc. are controlled by chemical weathering and physical erosion of watershed rock, which is the most important factor controlling the distribution of elements in the study area; while heavy metals (such as Cu and Cd etc.) are related to the dissolution of elements in the formation of AMD and the adsorption of fine particles such as organic matter. In addition, the ecological risks of Cd, Cu, Pb, Cr, and Zn are low, while the ecological risks of As and Sb are high.