Abstract:

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.

Key words: mountain and hilly area, Wuding, soil heavy metals, source, influencing factors