Physicochemical properties, metal availability and bacterial community structure in heavy metal-polluted soil remediated by montmorillonite-based amendments
Physicochemical properties, metal availability and bacterial community structure in heavy metal-polluted soil remediated by montmorillonite-based amendments
复制标题
蒙脱土改良剂修复重金属污染土壤的理化性质、金属有效性和细菌群落结构
DOI：
10.1016/j.chemosphere.2020.128010
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Wang Hou
中科院分区：
文献类型：
--
作者：
Qin Chencheng;Yuan Xingzhong;Xiong Ting;Tan Yong Zen;Wang Hou
粘土材料是重金属污染土壤修复技术中常用的材料。在本研究中，提出用镁(氢氧化镁/氧化镁)-蒙脱石固定污染土壤中的重金属，并通过毒性特征淋洗程序(TCLP)和社区参考顺序提取程序(BCR)来评价修复效果。镁蒙脱石的加入使土壤中重金属(铜、铅、锌、镉)的TCLP萃取率降低，促进了土壤中重金属从酸溶态向残渣态的转化。同时，MM还提高了土壤的pH值和水溶性有机碳(WSOC)。结果表明，镁蒙脱石对重金属的固定化主要是通过静电吸引、沉淀和与水溶性有机碳的络合作用来实现的。有趣的是，经镁蒙脱土(MM)处理的土壤中细菌群落多样性降低。纯镁蒙脱石的存在提高了变形杆菌、放线菌和细菌的相对丰度，但降低了类杆菌和酸性细菌的相对丰度。我们的结果表明，在蒙脱石改良剂中加入生物炭可以通过减弱土壤中粘粒和WSOC含量与土壤细菌之间的负相关性来减轻对土壤微生物的损害。
Clay materials are commonly used in remediation techniques for heavy metal contaminated soil. In this study, a magnesium (Mg(OH)2/MgO)-montmorillonite was proposed to be utilized for heavy metals immobilization in contaminated soil, with the remediation efficiency evaluated through the toxicity characteristic leaching procedure (TCLP) and the community bureau of reference sequential extraction procedure (BCR). The addition of magnesium-montmorillonite resulted in lower TCLP extractability for the heavy metals (Cu, Pb, Zn and Cd) in soil as it promoted their conversion from acid soluble fraction to residual fraction. Meanwhile, MM raised the soil pH and water-soluble organic carbon (WSOC). It was demonstrated that the immobilization of heavy metal in the presence of magnesium-montmorillonite was primarily induced by electrostatic attraction, precipitation and chelation with water-soluble organic carbon. Interestingly, a decreased bacterial community diversity was observed in soil treated by magnesium-montmorillonite (MM). The presence of pure magnesium-montmorillonite promoted the relative abundance ofProteobacteria,ActinobacteriaandFirmicutesbut reduced that ofBacteroidesandAcidobacteria. Our results suggest that integrating the biochar into montmorillonite-based amendments can alleviate the damage to soil microorganisms by weakening the negative correlation between the two factors (content clay and WSOC in soil) and soil bacteria.