Industrial by-products (ferrous sulfate minerals and stone powder) can serve as amendments to remediate Cd-As paddy soil, alleviating Cd-As accumulation in rice

Our previous research has shown that industrial by-products such as ferrous sulfate mineral and stone powder as amendments can remediate Cadmium (Cd) and arsenic (As) soil. However, their role in the soil-rice system is unknown. Therefore, this article explored the effects of the combined use of industrial by-products and commercial conditioners on the accumulation of Cd-As in weakly alkaline and acidic soil-rice systems. Potted experiments shown that SL (stone powder+ferrous sulfate mineral) and SLW (stone powder+ferrous sulfate mineral+Weidikang conditioner) could reduce the availability of Cd-As in soil by adjusting soil pH and CEC, increase iron film content on the root surface, strengthening the “barrier” for fixing Cd-As. Brown rice Cd was lower than the national food safety standard of 0.20 mg kg⁻¹ (GB2762–2022). 1 % SLW could reduce brown rice As from 1.24 mg kg⁻¹ to 0.83 mg kg⁻¹. The results of field experiments confirmed the conclusion of pot experiments. SL and SLW not only reduced the accumulation of Cd-As in rice but also significantly increased rice yield by 16.58 % and 11.68 %, respectively. Compared to the two types of conditioning agents sold in the market, the material costs have been reduced by 79.1 % -86.5 % and 12.4 % -43.3 %, respectively. In summary, this study demonstrates that ferrous sulfate minerals and stone powder could efficiently remediate Cd-As pollution in paddy soil under different acid-base conditions, providing an application example for the resource utilization of industrial by-products for the remediation of Cd-As pollution in paddy soil.