Study on the Remediation Effect of Different Conditioners on Soil Cadmium and Arsenic Compound Pollution

The problem of Cd and As compound pollution in farmland soil is becoming increasingly serious, and the remediation of heavy metal-polluted arable land is an urgent agricultural and environmental protection problem that needs to be solved today. The experiment was carried out by selecting two pieces of farmland contaminated by Cd, As composite pollution, and using a variety of different soil conditioners to remediate their soil pollution. The results show that the remediation effect of soil conditioners for As was unsatisfactory, and the effective state As content in the soil increased after soil conditioners were treated. The soil commodity conditioner (SC1) and soil commodity conditioning special fertilizer (SC2) treatments significantly increased the content of Cd in the soil residue state, which was 203% and 160% higher than that of the control (CK), whereas the SC1 and LM treatments reduced the content of As in the soil residue state, which was 31% and 54% lower, respectively. In addition, the LM treatment significantly reduced the Cd content in rice grains by 39% to 66%. However, for the cumulative effect of As, SC1, humic acid (HA), biomass charcoal (BC) and MP treatments all led to an increase in As content in rice kernels compared to CK. This study demonstrated the limitations of traditional conditioners in the remediation of Cd and As composite contaminated soils, which could not effectively reduce the effectiveness and cumulative effects of the two heavy metals at the same time. Therefore, when developing new soil remediation technologies in the future, more attention needs to be paid to the design and optimization for the characteristics of composite contaminated soils.