| 水分管理协同含铁碱性材料对污染土壤-水稻中Cd和As迁转的影响与阻控机制 |
| 摘要点击 244 全文点击 8 投稿时间：2025-05-19 修订日期：2025-08-04 |
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| 中文关键词 石灰石 铁粉 镉（Cd） 砷（As） 水稻土 稳定化 |
| 英文关键词 limestone zero-valent iron cadmium （Cd） arsenic （As） paddy soil stabilization |
| DOI 10.13227/j.hjkx.202505175 |
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| 中文摘要 |
| 目前全国土壤镉（Cd）和砷（As）复合污染已成现实，如何实现Cd和As同步阻控是土壤安全利用的瓶颈. 采用水分管理（淹水/干湿交替）协同零价铁（ZVI）和石灰石（LS）的组配措施修复Cd-As污染水稻土，研究其对土壤Cd和As的阻控机制以及Cd和As在土壤-水稻系统的迁转归趋可为污染土壤的再利用奠定理论基础. 其中，ZVI的施用量分别为土壤质量的1%（ZVI1）和4%（ZVI4），LS与ZVI组配的施用量为0.3%（ZVI1+LS和ZVI4+LS）. 结果表明淹水较干湿交替显著提高土壤pH，增幅为0.24~0.85. 淹水协同ZVI4+LS处理对土壤Cd的钝化效果最佳，土壤可交换态Cd（T-EC-Cd）和残渣态Cd（T-RES-Cd）分别减少了12.33%和2.94%，而易还原铁锰结合态Cd（T-FE-Cd）、有机结合态Cd（T-OM-Cd）和晶质氧化铁结合态Cd（T-FEC-Cd）分别增加了12.06%、1.94%和1.27%. 结合土壤胶体Cd形态变化以及钝化剂对Cd吸附的试验结果表明，淹水协同ZVI可促使非晶质氧化铁结合态Cd形成；LS促使CdCO3和Cd（OH）2沉淀的生成. 干湿交替协同ZVI4能更有效降低土壤As生物有效性，主要是由于铁氧化物与土壤As生成更多的Fe2As4O9和FeHAsO4等Fe-As共沉淀物质. 钝化剂对水稻品质的变化与土壤Cd和As活性的变化趋势基本一致. 干湿交替协同ZVI4+LS处理可显著降低水稻根部对Cd和As的富集及其向籽粒的转运能力，水稻籽粒ω（Cd）和ω（As）分别降至0.13 mg·kg-1和0.19 mg·kg-1，均低于国家安全标准（GB 2762-2022），实现土壤-水稻中Cd和As的同步阻控. 籽粒Cd的主要积累途径由根吸收为主转为根吸收（27.47%）和秸秆中Cd再分配（72.53%），As的主要积累途径以秸秆再分配为主. |
| 英文摘要 |
| Arable land polluted by cadmium （Cd） and arsenic （As） is a widespread problem. We applied zero-valent iron （ZVI） and ZVI mixed with limestone （ZVI + LS） as soil amendments， combined with two types of water management strategies， including flooding （F） and alternate wetting and drying （AWD）， to study their immobile ability to prevent Cd and As simultaneously in paddy soil and rice systems. This study lays a theoretical foundation for the reuse of contaminated soils. The dosages of ZVI were set at 1%（ZVI1） and 4%（ZVI4） of the soil mass， while the dosage of LS was 0.3% when mixed with ZVI （ZVI1 + LS and ZVI4 + LS）. The results showed that F management， compared to AWD management， raised soil pH by 0.24-0.85. The immobile effect of F management combined with ZVI4 + LS was the most effective treatment. Specifically， the available fraction （T-EC-Cd） and residual fraction Cd （T-RES-Cd） in the soil decreased by 12.33% and 2.94%， respectively. In contrast， the readily reducible iron and manganese fraction Cd （T-FE-Cd）， organic fraction Cd （T-OM-Cd）， and crystalline iron oxide fraction Cd （T-FEC-Cd） increased by 12.06%， 1.94%， and 1.27%， respectively. The application of ZVI could promote the formation of the amorphous iron oxide fraction of Cd， while LS facilitated the precipitation of CdCO3 and Cd（OH）2 through the speciation changes of Cd in soil colloids and the adsorption mechanisms by amendment. However， the immobile effect of ZVI4 under AWD management was the most effective treatment for As， mainly due to the formation of more Fe-As co-precipitates， such as Fe2As4O9 and FeHAsO4. The changes in rice quality and physiological and biochemical indexes influenced by the amendments were consistent with the trends in soil Cd and As bioavailability. AWD management combined with the ZVI4 + LS treatment significantly reduced the accumulation of Cd and As in rice roots and their translocation to the grains， which were both less than the national safety standards （GB 2762-2022）. The primary pathway for Cd accumulation in the grains changed from root uptake to a combination of root uptake （27.47%） and Cd remobilization from the straw （72.53%）， while As accumulation remained predominantly through straw remobilization. |
