The Relationship between Heavy Metal Contents of Soils and Rice in Coastal Areas, Fujian Province, including Influencing Factors

Lead content of soil in coastal areas of Fujian Province is higher than that of soil in other areas and in the background level of China, and is therefore of significant influence on food safety and the ecological environment. Based on Pb and Cd contents of 58 suites of soil and rice samples, the characteristic of content and its influencing factors are discussed. Results show that the concentrations and BCF values of heavy metals decrease rapidly from root to stem leaf to rice, and concentrations of toxic elements like arsenic and lead decrease more obviously than those of plant nutrients such as copper and zinc, indicating that rice root has a barrier effect for toxic element uptake. Lead content of rice is positively correlated with that of soil, indicating the soil is the main source of lead in rice. Lead content of rice is negatively correlated with organic carbon contents and pH of soil. This indicates that the abundance of organic carbon and neutral-alkaline soil conditions may reduce bioavailability of lead in soils. The bio-concentration factor of cadmium has a good correlation with physicochemical conditions of soil. Abundance of organic carbon, Al₂O₃, Fe₂O₃, CaO, MgO and S can hinder the uptake of cadmium by rice and reduce its eco-risk. This research provides the foundation for restoring paddy fields polluted by heavy metals and contributes in predicting the impact of heavy metal pollution of soil on the safety of rice.