滇中高山丘陵区土壤重金属来源及影响因素——以武定县为例

Sources and Influencing Factors of Soil Heavy Metals in the High Mountain and Hilly Area of Central Yunnan:Taking Wuding County as an Example

以武定县为例,探明土壤重金属的来源及影响因素,以期为高山丘陵区土壤重金属污染防治提供理论依据。笔者分析了武定县重金属含量和空间分布特征,运用多元统计分析方法,结合地质特征综合分析土壤重金属来源和影响因素。结果表明,表层土壤重金属的空间分布特征与深层土壤具一致性。除Cd、Pb、Zn外,表层与深层土壤重金属含量无显著差异。受区内断裂带控制,重金属主要富集在铁铜、铅锌多金属成矿带上。在垂向分布上,Cd受人为因素影响较大,Cr、Ni受自身理化性质的控制,As、Cu、Hg、Pb、Zn可能由地质背景控制。8种重金属均来源于成土母质,Cd、Pb、Zn受矿产开采的影响较大,Cr、Ni主要来源于成土母质,As、Cd、Cu、Hg、Pb、Zn来源于多金属成矿带高背景值成土母质与矿产开采的共同影响。不同土壤类型和土地利用类型中重金属含量不同,土壤重金属含量也与有机碳、铁锰氧化物、粘土矿物、养分元素、pH具有较显著的相关关系。

Taking Wuding County as an example,the source and influencing factors of heavy metals in soil were explored to provide a theoretical basis for the prevention and control of soil heavy metal pollution in the mountain and hilly area.This paper studied the content and the spatial distribution characteristics of heavy metals in Wuding County of Yunnan Province,used multivariate statistical analysis methods combined with geological characteristics to comprehensively analyze the sources and influencing factors of soil heavy metals.The research results show that:the spatial distribution characteristics of heavy metals in the surface soil are consistent with those in the deep layers.Except Cd,Pb and Zn,there was no significant difference in the content of heavy metals in the surface and deep layers.Controlled by the fault zone in the region,heavy metals are mainly concentrated in the iron-copper and lead-zinc polymetallic metallogenic belts.In the vertical distribution,Cd is greatly affected by human factors,Cr and Ni are controlled by their own physical and chemical properties.As,Cu,Hg,Pb,and Zn may be controlled by geological background.8 kinds of heavy metals are all derived from soil parent material,Cd,Pb and Zn are greatly affected by mining,Cr and Ni are derived from soil-forming parent materials.As,Cd,Cu,Hg,Pb and Zn are derived from the combined effects of high background value soil-forming parent material and mineral mining in the polymetallic metallogenic belt.The contents of heavy metals in different soil types and land use types are different.Soil heavy metal content also has a significant correlation with organic carbon,iron and manganese oxides,clay minerals,nutrient elements,and pH.