School of Geography and Planning, Sun Yat-sen University, Guangzhou, 510275, China.
School of Environmental Science and Engineering, Guangdong Provincial Key Lab for Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510006, China.
Environ Pollut. 2021 Jun 15;279:116862. doi: 10.1016/j.envpol.2021.116862. Epub 2021 Mar 12.
Liming is a safe and effective remediation practice for Cd contaminated acid paddy soil. The fate of Cd can also be strongly influenced by redox chemistry of sulfur. But it is unclear if, to what extent and how the combination of liming and sulfur mediation could further control Cd uptake by paddy rice. A rice cultivation pot experiment was conducted to evaluate the impact of different sulfur forms (S and SO in KSO) on the solubility, uptake and accumulation of Cd in the soil-paddy rice system and how liming and reducing organic carbon mediate the process. Results showed that under neutral soil circumstances achieved by liming, co-application of KSO and glucose significantly reduced brown rice Cd by 33%, compared to liming alone. They made it more readily for Cd to be precipitated into CdS/CdS or co-precipitate with newly formed FeS/FeS/iron oxides. The higher pH balancing capability of KSO as well as liming kept the newly formed sulfide or iron containing minerals negatively charged to be more prone to adsorb Cd, that kept the porewater Cd the lowest among all the treatments. Individual KSO showed significant promoting effect on soil Cd solubility due to SO chelation effect. Furthermore, KSO had much weaker inhibiting effect on Cd translocation from root to grain, it showed no significant attenuating effect on brown rice Cd. S containing treatments displayed weaker or no attenuating effect on brown rice Cd due to its strong soil acidification effect. On the basis of liming, organic carbon induced sulfur (KSO) mediation showed great application potential for safe production on large areas of acid paddy soil contaminated by Cd.
石灰处理是一种安全有效的修复 Cd 污染酸性稻田的方法。Cd 的命运也可以受到硫的氧化还原化学的强烈影响。但是，尚不清楚石灰和硫调解的结合将如何以及在多大程度上进一步控制水稻对 Cd 的吸收。进行了一项水稻栽培盆试验，以评估不同硫形式（KSO 中的 S 和 SO）对土壤-水稻系统中 Cd 溶解度、吸收和积累的影响，以及石灰和减少有机碳如何调节这一过程。结果表明，在石灰实现的中性土壤条件下，与单独使用石灰相比，KSO 与葡萄糖的共同施用使糙米 Cd 减少了 33%。它们使 Cd 更容易沉淀为 CdS/CdS 或与新形成的 FeS/FeS/铁氧化物共沉淀。KSO 具有更高的 pH 平衡能力以及石灰作用，使新形成的硫化物或含铁矿物带负电荷，更易于吸附 Cd，使所有处理中孔水 Cd 最低。由于 SO 螯合作用，单独的 KSO 对土壤 Cd 溶解度有显著的促进作用。此外，KSO 对 Cd 从根部向籽粒的迁移有较弱的抑制作用，对糙米 Cd 没有显著的减弱作用。由于其强烈的土壤酸化作用，含 S 的处理对糙米 Cd 显示出较弱或没有减弱作用。在石灰处理的基础上，有机碳诱导的硫（KSO）调解对大面积受 Cd 污染的酸性稻田的安全生产具有很大的应用潜力。
