Characteristics and health risk assessment of heavy metals in soil-rice system in the Ganzhou area, Jiangxi Province

Total 954 pairs of rice grain and soil samples were collected to investigate the distribution of heavy metals in the soil-rice system and their human health risk in Ganzhou City.The contents of Cd, Cr, Hg and Pb in rice seeds and root soil and the pH value of root soil were analyzed, and the health risk assessment model derived by USEPA was used to evaluate health risk caused by heavy metals.The results show that exceedance rate of heavy metals in rice decreases with the increase of soil pH; Cd is the most severely contaminated metal; and migration ability of Cd and soil pH value are the main factors that determined whether heavy metals in rice grains exceed the standard.The results of health risk assessment show that the total non-carcinogenic risk index(HI) of heavy metals is less than 1, indicating that there is almost no risk of chronic diseases from ingesting rice.The carcinogenic health risk value is 7.10×10^-3; Cd is the most important carcinogenic risk factor; and Cr and Pb carcinogenic risk is within the acceptable range.According to the human health risk zoning, there are risks in Shangyou, Xingguo and Nankang, which is worth paying more attention.Although heavy metals do not exceed the standard significantly, the relevant authorities should take exceedance of Cd seriously, and should take Cd as the priority in the prevention and control of heavy metal pollution in the soil of Ganzhou City.