Geochemical characteristics and health risk assessment of heavy metal Cd in soil-rice system inWestern Jiangxi Province

This paper is the result of land quality geochemical survey engineering. Objective Metal elements mainly enter the human body through the food chain, thus affecting health. Research on the geochemical characterization of heavy metal elements in the soil-rice system is significant for the scientific management of arable land, the guarantee of food security and the implementation of the strategy of a healthy China.Methods A total of 129 sets of rice seeds and root soil samples were systematically collected, analyzed by chemical analysis to obtain geochemical data such as As, Cd, Hg, Pb, Cr, pH, and soil Cd morphology, thus using the human health risk model to assess the health risk in the study area. Results (1) The average soil Cd content in the study area was 0.49 mg/kg, which was significantly higher than the background value of Jiangxi surface soil.There were 80 soil samples Cd content higher than the risk screening value, accounting for 62%.There were 57 rice seeds with excessive Cd content, the rate of exceeding the standard was 44%.(2) The results of the pollution evaluation of soil Cd and safety evaluation of rice seeds Cd in the study area were poorly correlated.Soil pH was the major influencing factor, with soil alkalinity increasing, soil Cd content increased by 2.3 times, but rice seeds Cd content decreased by 4.5 times.(3) The three fugitive forms of water-soluble, exchangeable and residual Cd in the soil had a significant effect on the Cd content of rice seeds, and the bio-efficacy of Cd was enhanced in a strongly acidic soil environment.(4) Children in the study area have greater health risks than adults, with non-carcinogenic and carcinogenic risk factors dominated by the heavy metal Cd.Conclusions The correlation between soil Cd and rice seeds Cd content in the study area is relatively poor, and there are some limitations of misjudgment and omission according to the current norms; the health risk evaluation results revealed that there is a human health risk caused by rice Cd intake in the study area.