Preliminarily pollution assessment and source analysis of heavy metals in agricultural soil from Xinjie Village, China

Abstract

To explore the overall pollution level of heavy metals in agricultural soil and identify its main pollution sources, the selected eight heavy metals (As, Hg, Cr, Cu, Ni, Pb, Fe, and Cd) in 6 sampling sites of Xinjie Village from Qingjiang River Basin were detected. Nemerow index, Geo-accumulation index and Potential ecological risk index were used to evaluate the soil environmental quality. Results showed that the concentrations of Cd in all 6 sampling sites were relatively higher than the risk screening values for soil contamination of agricultural land. The overall heavy metal pollution level based on Nemerow index was slight. Specifically, the pollution level of Cd was moderate, while other metals were basically at clean level. Results of Geo-accumulation index showed Hg (moderately contaminated to heavily) and Cd (uncontaminated to moderately contaminated) were potential primary pollutants. The comprehensive potential ecological risk based on Potential ecological risk index was moderate, with the potential ecological risk of Cd (considerable) and Hg (moderate) higher than that of other metals. Therefore, the agricultural soil pollution in Xinjie Village was a combined pollution and mainly composed of Cd and Hg. Source analysis showed anthropogenic activities such as industrial and agricultural production were the main contributors to the accumulation of heavy metals in agricultural soil. Cd pollution mainly came from agricultural production (fertilization) and industrial emissions; the pollution source of Hg were mostly industrial emissions and the resulting atmospheric subsidence. Finally, the targeted countermeasures were developed for heavy metal pollution of agricultural soil based on the different pollution source characteristics.