Spatial Heterogeneity Analysis and Source Identification of Heavy Metals in Soil: A Case Study of Chongqing, Southwest China
Background: Heavy metal pollution in urban soil is an important indicator of environmental pollution. Selecting the best interpolation method can accurately reflect the distribution characteristics and pollution characteristics of heavy metals in soil. Source analysis and identification of heavy metals in soil can reveal the important content of heavy metal pollution in soil, which is conducive to the implementation of effective management and protection strategies.Materials and methods: In
... study, the grid sampling at 40 cm depth was conducted in the whole study area using the principle of uniform sampling, and the characteristics of As, Cu and Mn in the soil of the main urban area of Chongqing in southwestern China were investigated. The interpolation accuracy and results of ordinary Kriging method (OK), inverse distance weighting method ( IDW ), local polynomial method ( LPI ) and radial basis function method ( RBF ) for three elements were analyzed and compared, and the main sources of three heavy metals were studied.Results: The results showed that As(5.802 mg·kg − 1), Cu (23.992 mg·kg −1) and Mn(573.316 mg·kg −1) in the soil of the study area were all moderate variations. The prediction smoothing effect of LPI and OK methods on the three metals is strong, which cannot reflect the local point source pollution information. The interpolation results of IDW method and RBF method largely retain the maximum and minimum information of element content. The results of classification and regression analysis confirmed the main sources of heavy metals: population density mainly affected Cu (0.539), slope mainly affected Mn (0.206), and water quality mainly affected As (0.453).Conclusions: The results of this study provide a reference for the formulation of scientific decisions and strategies. Effective soil heavy metal pollution control and management strategies should be developed to ensure the quality of urban soil environment.