Soil Heavy Metal Content, Pollution, and Influencing Factors in Typical Farming Area of Sichuan Basin

Abstract

In order to identify heavy metal contents, the pollution characteristics and influencing factors of soil in typical farming areas in the Sichuan basin were analyzed, with Jiangjin District of Chongqing City chosen as the study area. Two hundred and forty-seven topsoil samples were collected and analyzed using the Nemerow index (NPI), geographical information system (GIS), and geodetector method. The results demonstrated that: 1 the arithmetic means of Cd, Cu, and Zn in the topsoil were 1.22, 1.10, and 1.98 times that of the soil background values in western Chongqing, respectively. 2 The high-value areas of the six heavy metals were mainly distributed in the northern, western, and central Jiangjin district, whereas the low-value areas were distributed in the eastern and southern Jiangjin district. 3 The NPI showed that the polluted sample points accounted for 22.1% of the total sample points, indicating that the overall soil pollution was mainly safety and vigilance in general. The high value of NPI was distributed in Dingshan street in the northern Jiangjin district. 4 The explanatory power of stratum on the distribution of heavy metal contents in the topsoil was the strongest, followed by that of the topographic factor. The interaction effect of the stratum and topographic factors on the distribution of heavy metal content in soil was the strongest. The results showed that the stratum and topographic factors were the key factors affecting the distribution of soil heavy metal contents in the study area.