Spatial variation, health risk assessment and transfer model of heavy metals in a soil-rice system at a typical production field of Southeastern China

Abstract The spatial variation and transfer characteristics of heavy metals (HMs) in the soil-rice system is important for revealing HM pollution in rice production areas and guaranteeing the safety of rice products. In this research, 95 pairs of topsoil (0-20cm) and their corresponding rice samples from a production area of southeastern China were collected. The pollution status, spatial variation characteristics, and HMs transfer models were studied. The main conclusions indicated that the mean values of total cadmium (Cd), copper (Cu), lead (Pb), Zinc (Zn) and nickel (Ni) concentrations were 0.21, 28.65, 27.02, 38.50, 98.75 mg kg-1, respectively. The Cd had the maximum potential ecological risk to the system, but the overall potential risk in this production area was low. The maximum concentration of rice Cd was three times greater than the threshold value, indicating that Cd could accumulate in the human body and pose a health risk by consuming parts of rice samples by residents. The children had a higher exposure risk to HMs than the adult, especially for Cd and Cu. The spatial distributions of HMs in rice were similar to that in soils, reflecting that the concentration of HMs in soil affected the accumulation of HMs in rice. The spatial distribution patterns of HM enrichment index (EI) revealed that the transfer abilities of Ni, Zn, and Cd were strong in the west. Principal component analysis showed that soil physicochemical properties had significant effects on the HMs transfer.