Trace Elements Geochemical Characteristics of Reservoir Sediments Affected by Acid Mine Drainage
Journal of Jilin University(Earth Science Edition)
2020, 50 (4):
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.
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