CHEMICAL SPECIATION AND RISK ASSESSMENT OF TRACE ELEMENTS IN THE SOIL OF THE AGRICULTURAL AREA IN HUAINAN, CHINA

In this study, 30 soil samples were collected from the agricultural area of Huainan of Anhui Province, China. The concentrations of six toxic trace elements were determined, the distribution characteristics and chemical speciation were analyzed, the pollution status and potential ecological risk of trace elements were comprehensively evaluated by single factor index, geo-accumulation Index (I-geo), the potential ecological risk index and RAC code method. Results showed that the average concentrations of Ni, Cu, Zn, Pb, Cr and Cd in soil were 20.19 +/- 8.20, 18.17 +/- 4.67, 37.61 +/- 10.85, 10.76 +/- 3.73, 40.61 +/- 15.06, 0.14 +/- 0.05 mg/kg, respectively. With increasing soil depth, the concentration of Cr increases while Cd and Pb decrease. It is speculated that Cd and Pb were affected by anthropogenic activities. All the trace elements mainly associate with the residual fraction indicating lower mobility and Cd exists in a relative higher carbonate bound form suggesting it pose a great mobility and bioavailability. The single factor index and the geo-accumulation index (I-geo) indicate that pollution caused by Cd to a certain degree of pollution, while pollution caused by other elements belong to the level of uncontaminated. The results of the potential ecological risk index and RAC also shows that Cd has an extremely strong potential ecological risk. Attention should be paid to the pollution caused by Cd. This study provides a theoretical basis for the prevention and control of soil pollution and for agricultural products safety in the study area.