Ecological in-situ passivation and morphological transformation of Cd in paddy fields in mining areas using biochar
A paddy soil Cd pollution remediation test was conducted to analyze the effects of in-situ passivation of biochar on ecological remediation of cadmium(Cd)-contaminated paddy soil in mining areas.Three treatments of sepiolite,biochar,and blank control were performed.The gradient diffusion film technique was used to study the bioavailability of Cd in rice rhizosphere soil and determine its effects on the bioavailability of Cd in rice rhizosphere soil and the transformation of soil Cd form.The results showed that:biochar input affected the Cd morphological ratio of rice rhizosphere soil in Cd-contaminated paddy fields.Biochar changed the form of Cd in paddy soil and significantly increased the proportion of residual Cd content in the soil by 27.84%,which was conducive to changes in other forms of Cd to a more stable residual state.Biochar changed the Cd bioavailability of rice rhizosphere soil in the Cd-contaminated paddy fields.Compared with that in the blank control,biochar reduced Cd bioavailability in rhizosphere soil by 40.90%and Cd content in the soil by 9.53%.Cd bioavailability in soil treated with sepiolite was reduced by 83.90%when compared with that in soil treated with biochar.The effective Cd content in soil treated with sepiolite was reduced by 7.73%compared to that in soil treated with biochar.Biochar improved the soil quality of Cd-polluted paddy fields in mining areas.Biochar improved rice soil quality.Compared with that in the blank control,the organic matter of the soil treated with biochar increased by 6.75%,the cation exchange capacity of the soil increased by 8.44%,and the pH value of the soil increased by 7.44%.Compared with that in the sepiolite control,soil organic matter after biochar treatment increased by 2.95%,cation exchange capacity increased by 9.22%,and soil pH value decreased by 13.33%.In-situ passivation of biochar could effectively reduce Cd bioavailability in Cd-contaminated paddy soil and improve the ecological restoration level.
Cd-polluted rice fieldin situ passivationCd morphological transformationbiocharmining area
万方数据
维普
