Characteristics and Correlation Analysis of the Spatial Distribution of Heavy Metals in Arable Soils with Different Soil-Forming Matrices

The problem of the contamination of soils with high background values of heavy metals has attracted increasing attention. In this paper, the contents, spatial distribution characteristics and correlations of five heavy metals in seven types of arable soils with different soil-forming matrices were analyzed by using Kriging spatial interpolation, descriptive statistics and correlation analysis to clarify the spatial distribution of heavy metals in different soil-forming matrices, and to explore the influence of parent rocks on the spatial distribution and concentration of heavy metals. The results showed that the Cd contents of the seven soil-forming parent materials exceeded the background values recorded for soils in Yunnan Province and that metamorphic rocks such as mudstone, argillaceous rock, purple rock, and carbonate rock exceeded the risk screening values. The average Pb, Cu, and As contents were lower than the background values recorded for soils in Yunnan Province and smaller than the risk screening values for agricultural land. Carbonate areas have a large area of contamination, while metamorphic mudstone areas have a relatively small percentage of contamination. The correlations of heavy metals in different soil-forming matrices varies, and the source of each element and its correlation can be further analyzed and verified by means such as the source analysis method. The results of this study are crucial for pollution prevention and the analysis of the source of heavy metal soil contamination.