卡房尾矿库土壤重金属化合物对微团聚体稳定性的影响

Effects of soil heavy metal compounds on the micro-aggregate stability in Kafang tailing pond

为了探究云南省卡房尾矿库土壤微团聚体结构稳定性的影响因素,合理反映尾矿库土壤整体稳定性情况,以卡房尾矿库土壤微团聚体和重金属化合物(As2O3、Co3O4、Cr2O3、CuO、NiO、ZnO)为研究对象,分析了微团聚体结构稳定性与重金属化合物含量之间的关系。结果表明,尾矿库土层深度0~2、2~5、5~8、8~15 m的平均重量直径(MWD)和几何平均直径(GMD)均值分别为0.086 mm和0.048 mm、0.083 mm和0.052 mm、0.031 mm和0.019 mm、0.048 mm和0.029 mm,土层深度0~5 m的微团聚体结构稳定性最强。不同土壤深度6种重金属化合物含量变异系数为0.106~0.743,均呈现中等变异,且所测得的样本中75%数据的拱高基台比大于0.75,具有较强程度的空间自相关。6种重金属化合物在尾矿库土壤中呈现2种不同的分布规律:随土层深度的增加,As2O3与NiO的含量逐渐降低;在0~8 m深度内CuO、ZnO、Co3O4与Cr2O3的含量均匀分布或者逐层下降,在8~15 m深度内各重金属化合物含量上升。对卡房尾矿库土壤微团聚体结构稳定性产生影响的重金属化合物为CuO和ZnO,在0~8 m深度内CuO对微团聚体稳定性的贡献水平为ZnO的2倍,在8~15 m深度内两者贡献水平相同。综上,土壤中CuO和ZnO的含量会对微团聚体结构稳定性造成影响,其中CuO对土壤微团聚体结构稳定性的贡献水平最高。

In order to explore the factors affecting the structural stability of soil micro-aggregates in the Kafang tailing pond in Yunnan Province,and reasonably reflect the overall stability of the soil in the tailing pond,the relationship between the structural stability of the micro-aggregates and the content of heavy metal compounds was analyzed by taking the soil micro-aggregates and heavy metal compounds(As2O3,Co3O4,Cr2O3,CuO,NiO,and ZnO)in the Kafang tailing pond as the test object.The results showed that the mean values of mean weight diameter(MWD)and geometric(GMD)in the layers of 0~2 m,2~5 m,5~8 m,and 8~15 m in the tailing pond were 0.086 mm and 0.048 mm,0.083 mm and 0.052 mm,0.031 mm and 0.019 mm,0.048 mm and 0.029 mm,respectively.The micro-aggregates structure within the depth of 0~5 m was the most stable one.The variation coefficients of the contents of six heavy metal compounds in soil at different depths were 0.106~0.743,showing moderate variation,and 75%of the measured samples had[C/(C0+C)]values greater than 0.75,showing a strong spatial autocorrelation.The six heavy metal compounds showed two different distribution patterns in tailing pond soil,with increasing soil depth,the content of As2O3 and NiO decreased gradually.The contents of CuO,ZnO,Co3O4,and Cr2O3 were uniformly distributed or decreased from layer to layer in the depth of 0~8 m,while the contents of each heavy metal compound increased at the depth of 8~15 m.The CuO and ZnO were the heavy metal compounds that affected the structural stability of soil micro-aggregates in the Kafang tailing pond.The contribution level of CuO to the stability of the micro-aggregates was twice that of ZnO at the depth of 0~8 m,and both contribution levels were the same within a depth of 8~15 m.In summary,the contents of CuO and ZnO in soil affected the structural stability of micro-aggregates,of which CuO had the most contribution to the structural stability of micro-aggregates.