Toward safe rice production in As-Cd co-contaminated paddy soils: Biogeochemical mechanisms and remediation strategies

The safe production of rice is linked to a range of critical needs such as regional food supplies, people's livelihoods, and human health. Arsenic (As) and cadmium (Cd) are two highly toxic elements, and As-Cd co-contamination in paddy soils is prevalent, posing significant food safety challenges. The biogeochemical contrasts of As and Cd complicate the management of their co-contamination in paddy soils. This review synthesized advances in understanding the distinct behaviors of As and Cd in rice paddies, along with synergistic strategies for reducing As and Cd bioavailability in the soil-rice system. The strategies included the use of synthetic soil amendments, optimizing water, fertilizer and cropping management practices, developing low As/Cd-accumulating rice cultivars through genome editing and mutation breeding, and combined measures. Finally, future research perspectives were provided to maintain sustainable rice production in As-Cd co-contaminated paddy soils. This review offers a comprehensive overview of both foundational insights into the behavior of As and Cd in paddy systems and practical applications for mitigating their co-contamination, ensuring safe rice production.