Source identification of soil Cu, Zn, Pb, and Cd from anthropogenic activities by decision tree analysis in fuyang county, China

An investigation on the arable layer of agricultural land in Fuyang County, China was conducted for the total content of Cu, Zn, Pb, and Cd and analyzed in order to identify the main origin of these metals using the CART decision tree analysis method. By analysis of 102 surface soil samples, high concentrations accompanied with long range of variation suggested anthropogenic sources for Cu, Zn, Pb, and Cd. Further results of CART decision tree analysis showed that: (i) anthropogenic activities including industrial emission, vehicle-related activities, domestic emission and agricultural activities were the main sources for soil Cu, Zn, Pb. and Cd accumulation in the study area; and (ii) Soil organic matter and pH levels influenced the spatial distribution of soil heavy metals. By quantitatively comparing the importance of the independent parameters, we found that industrial emission was the most important source for soil Cu, Zn, Pb, and Cd content. Further correlation analysis confirmed the results by CART and proved CART an efficient method to identify heavy metal sources.