Soil arsenic concentration in paddy fields and its transfer to rice (Oryza sativa L.) grain in Pearl River Delta

The rice (Oryza sativa L.) root, straw, grain and corresponding surface soils (0-15cm) were collected in paddy fields of Pearl River Delta area, the arsenic concentrations in soils and different parts of rice plant were analyzed, and the correlations between soil arsenic and basic soil properties, arsenic transfer in soil –rice system were studied in this paper. The results indicated that soil arsenic concentrations ranged from 1.83 to 18.14 mg·kg-1, soil arsenic negatively correlated with soil organic matter, sand content, positively correlated with soil silt content. The arsenic concentrations in rice grain ranged from 0.21 to 0.43 mg·kg-1, met the requirement of the national food hygiene standards (0.7 mg·kg-1). The distribution of arsenic in different parts of rice plant was root straw husk rice grain. Arsenic concentrations in rice grain had significantly positive correlation with rice straw, whereas significantly negative correlation with Si/As molar ratio, P/As molar ratio, which suggested decreasing As accumulation, and increasing Si and P accumulation in rice straw can decrease As concentration in rice grain.