Spatial heterogeneity analysis and source identification of heavy metals in soil: a case study of Chongqing, Southwest China

Abstract Background Heavy metal pollution in urban soil is an important indicator of environmental pollution. Selecting the best interpolation method can accurately reflect distribution characteristics heavy metals soil. In addition, source analysis reveal and help manage protect environment. This study used a uniform sampling obtained total 342 points. After acid reduction, concentration As, Cu, Mn each sample was determined by ICP-MS (Agilent VISTA, USA). The accuracy results different spatial methods were compared CATREG model to identify sources Results average 5.802 mg kg ?1 , 23.992 573.316 respectively, lower than background value Chongqing. Compared other Chinese cities countries world, As Cu Chongqing, while only higher. inverse distance weighting (IDW) radial basis function (RBF) largely retained maximum information element concentration. Soil identification found that population density mainly affected (0.539), slope (0.206), water quality (0.453). highest hotspot (99% confidence interval), high (95% (90% interval) adjacent secondary Furthermore, located surrounding areas with > 3000/km 2 1000–3000/km . distributed along direction diffused from center periphery. Conclusions Different are significant for properties. have degree coincidence factors such as population. this research provide reference formulating effective control management strategies Graphical