SONG Jiangju1, LU Wangbiao1, ZHANG Zhen1, JIANG Ke1,2, ZHANG Qi1,2, ZENG Guangneng1,2,3, HUANG Chengling1,2, YANG Cheng1,2, ZHANG Lin3,4, LUO Weijun3,4, WANG Shijie3,4
(1.School of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang, 550025, China;
2.Guizhou Provincial Engineering Geological Disaster Prevention and Control Engineering Research Center of Guizhou Minzu University, Guiyang, 550025,China;
3.Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, Puding, Guizhou 562100,China;
4.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China)
Abstract：In order to understand the Cd pollution characteristics of paddy soil and rice, the paddy soil and corresponding rice samples were collected from some main rice producing areas in Guizhou Province. Soil pH and Cd content of all samples were tested. The results showed that the soil pH in the study area was 4.81～7.56, with an average of 6.45. The content of Cd in soil is 0.372～3.220 mg/kg with the average of 0.883 mg/kg. The rate of point exceeding the standard (risk screening value) is 96.43%, and the Cd content of soil in karst area is higher than that in non karst area. the Cd content in rice is 0.001～0.439 mg/kg, with an average of 0.039 mg/kg, and the proportion of samples exceeding the safety limit of rice is 3.65%. Further analysis shows that soil Cd in the study area is not only from the contribution of soil forming parent material (parent rock), but also affected by anthropogenic emissions. At the grain filling maturity stage, due to poor water conditions in paddy fields, the high frequency of soil oxidation environment or the long duration of oxidation environment may be one of the main reasons for the excessive Cd of rice. Therefore, in the process of rice planting, artificially ensuring sufficient water supply in paddy field during grain filling maturity is an effective way to reduce the content of Cd in rice and avoid exceeding the standard of Cd in rice.
Key words：cadmium；rice；soil；pollution characteristics；Eh
EARTH AND ENVIRONMENT Vol.51, No.1, Tot No.351, 2023, Page 67
