镉砷复合污染水稻土原位钝化修复技术研究进展

随着工农业的发展，稻田土壤正面临严重的重金属污染问题，水稻作为南亚和东南亚的主要粮食作物，稻米安全问题显得尤为突出。镉和砷两者在生物地球化学循环上有明显差异，因此镉和砷复合污染水稻土的修复一直是一个棘手的问题。综述了镉砷复合污染水稻土原位钝化技术的研究现状，将钝化技术梳理为氧化还原型、微生物转化累积型、材料型和耦合钝化技术四类。氧化还原型钝化技术重点指出稻田水分调控驱动的氧化还原电位Eh和pH变化、不同元素的生物地球化学循环、有机质等对镉和砷的迁移转化机制；微生物转化累积型钝化技术重点阐明功能微生物对砷和镉的吸收、转化、区室化、菌表吸附等作用机制；材料型钝化技术重点分析现有钝化材料的分类及其与镉和砷的固定化机制；耦合型钝化技术重点总结上述三种技术综合体系下，镉和砷的协同钝化应用。同时对未来镉砷复合污染水稻土的原位钝化修复提出展望，进一步探讨了镉砷在稻田土壤生物地球化学循环过程涉及的新型机制研究方向、修复钝化技术的创新延展趋势；期望在稳产、增产的基础上，寻求一种深度融合现代农业生产模式、保障稻田安全利用的土壤钝化改良技术体系或模式。

Research Progress on In-situ Passivation Remediation Technology of Cadmium and Arsenic Compound Contaminated Paddy Soil

Paddy soil is suffering from serious heavy metal pollution due to rapid industrial and agricultural development. As the main food crop in South Asia and Southeast Asia, rice safety issues are particularly prominent due to increasing heavy metal pollution. The remediation of cadmium and arsenic-contaminated paddy soil has always been a complex issue because of the differences in their biogeochemical cycle. Our study reviews the research progress on in-situ passivation technology for paddy soil contaminated by cadmium and arsenic. We group the passivation technology into four types: redox type, microbial transformation and accumulation type, material immobilization type, and coupled passivation technology. Redox type passivation technology focuses on the migration and transformation mechanisms of Cd and As driven by Eh, pH changes, biogeochemical cycles of different elements, and organic matter under the influence of water regulation in paddy fields; microbial transformation and accumulation type passivation technology focuses on clarifying the mechanism of functional microorganisms on the absorption, transformation, compartmentalization and bacterial surface adsorption of arsenic and cadmium; material immobilization type passivation technology focuses on the classification of existing passivation materials and their immobilization mechanisms with cadmium and arsenic; coupled passivation technology focuses on summarizing the application analysis of synergistic passivation of cadmium and arsenic under the comprehensive system of the above three technologies. Also, we propose the forecast on the in-situ passivation restoration of paddy soils contaminated by cadmium and arsenic. Besides, the research direction of new mechanisms involved in the biogeochemical cycle of cadmium and arsenic in paddy soil, the innovation and extension trend of remediation technology are further discussed. We hope that a soil passivation improvement technology model will be created in future, which integrates modern agricultural production models with a guarantee of food production and security.