滇西地区土壤重金属来源解析及空间分布

以滇西重金属地质高背景区为研究区,系统采集了4193件表层土壤样品,分析测试了As、Cd、Cr、Cu、Hg、Ni、Pb和Zn 8种重金属元素的含量,综合运用相关分析、主成分分析和单因素方差分析等经典统计方法探讨了土壤重金属来源和土壤重金属含量与成土母质、土地利用方式之间的关系,并利用地统计方法对重金属的空间分布特征进行...

Source identification and spatial distribution of soil heavy metals in Western Yunnan

A total of 4193 samples of surface soils were collected in the high background area of heavy metals in Western Yunnan, and the contents of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were analyzed. The sources of soil heavy metals and the relationship between soil parent materials and land use patterns were discussed by using correlation analysis, principal component analysis (PCA) and one-way analysis of variance (ANOVA). Moreover, the spatial distribution characteristics of soil heavy metals were analyzed by geostatistics. -The average contents of eight heavy metals in study area were higher than the national soil background value, but lower than the pollution risk screening value. The average As, Cd, Cu, Ni, Pb and Zn contents were equivalent to the background value of soils in Yunnan Province, and the average contents of Hg and Cr were 2.35 and 1.60 times greater than the background value, indicating heavy metals have been accumulated in different degrees in surface soils. The Cr, Cu and Ni in surface soils are mainly controlled by parent materials. However, Cd, Zn and Pb are mainly affected by human activities, including mining activities, transportation and coal combustion, and Cd and Zn are affected by parent materials to a certain extent. The As and Hg are predominantly anthropogenic sources, which include mining activities, agricultural activities and coal combustion. The average Cd, Cr, Cu, Hg and Ni concentrations were the highest in the soils derived from sedimentary rocks, and the average As, Cd, Cr, Cu, Hg, Ni and Zn concentrations were the highest in grassland. High-Cu, Ni and Cr concentrations occur in the western and southern part of study area, and are spatially associated with the occurrence of sedimentary rocks and copper, iron and mercury deposits in the area. The areas with high Pb, Cd and Zn contents are largely consistent with the distribution of Pb, Zn and Hg ore deposits in study area. High-As and Hg concentrations in surface soils has a high spatial consistency with the distribution of hydrothermal metal deposits such as lead-zinc deposits and mercury deposits, and also shows a high background characteristic in areas with intensive human activities.