Comparison of Four Amendments for Arsenic and Cadmium Combined Contaminated Soil

Arsenic (As) and cadmium (Cd) are common soil pollutants whose opposing geochemical behaviors must be taken into account in the development of cost-effective, environmentally friendly remediation strategies. In this study, a pot experiment with lettuce and a field experiment with wheat were performed to examine the impacts of zeolite, biochar, MnO₂, zero-valent iron (ZVI) individually and in binary combinations thereof on As-Cd pollution. The results of the pot experiment showed that biochar, MnO₂ and ZVI had good passivation effects on As and Cd when provided individually, but the effects of a combination of 0.2% ZVI/0.5% biochar or 0.2% MnO₂/0.5% ZVI were even better. These amendments were further investigated in a field experiment, which confirmed the positive effect of 0.2% MnO₂/0.5% ZVI. Therefore, ZVI/biochar and MnO₂/ZVI mixtures may offer effective solutions to the remediation of farmland soil contaminated with both As and Cd.