[Cd Enrichment Characteristics and Bioavailability of Soil-crops in the Migration Type Geological High Background Area of Poyang Lake, Jiangxi Province].

Abstract

To study the accumulation characteristics and bioavailability of Cd in the soil-crop system in the migration type geologically high background area, 140 groups of crops and soil samples were collected from the Jiulong area on the south bank of Poyang Lake. The results showed that the range of ω（Cd） of root soil was 0.03-0.65 mg·kg^-1, with an average of 0.16 mg·kg^-1, which exceeded the background value of soil in Jiangxi Province, reflecting the characteristics of high geological background of migration type. The over-standard rate of Cd in root soil was 6.43%, which was slightly polluted. Sesame had the strongest enrichment ability of Cd （404%）, followed by that of peanut （146%）. The enrichment ability of rice, Camellia oleifera, and Euryale seed was medium, while that of corn was weak. The root soil ω（active Cd） was 76.8 μg·kg^-1, and the bioavailability was 48.9%, among which rice was the highest with 98.6 μg·kg^-1 and 59.9%, respectively. Principal component analysis （PCA） showed that root soil Cd was mainly caused by the transport and accumulation of industrial and mineral pollutants in the upstream, reflecting the characteristics of the high geological background of the transport type. Correlation showed that the active and bioavailable Cd of root soil were mainly controlled by genetic sources, indicating that the activity of exogenously imported Cd was higher, and the ecological risk was higher.