Bioremediation of Cd-contaminated soil by earthworms (Eisenia fetida): Enhancement with EDTA and bean dregs
Bioremediation of Cd-contaminated soil by earthworms (Eisenia fetida): Enhancement with EDTA and bean dregs
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蚯蚓（Eisenia fetida）生物修复镉污染土壤：EDTA 和豆渣强化
DOI：
10.1016/j.envpol.2020.115191
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发表时间：
2020
影响因子：
8.9
通讯作者：
Zhang Zengqiang
中科院分区：
文献类型：
--
作者：
Liu Xiangyu;Xiao Ran;Li Ronghua;Amjad Ali;Zhang Zengqiang
由于镉污染土壤对生物体的毒性，镉污染土壤的修复已成为一个全球性的问题。本研究以赤子菜（Escherenia fetida）单独或与EDTA或豆渣复配处理土壤，研究其对土壤中Cd的去除效果。在35天的土壤培养实验中，测定了土壤中总镉和有效镉、土壤理化和生物学（土壤酶）性质、蚯蚓体内镉积累及其对镉的抗氧化反应。结果表明，蚯蚓对土壤中Cd具有一定的修复作用，EDTA和豆渣均能加速蚯蚓对Cd的修复。随着镉从土壤中迁移，镉在土壤中的含量随着暴露时间的延长而稳步增加，T2（单独镉）、T3（EDTA增强）和T4（豆渣增强）在第35天分别为8.11、12.80和9.26 mg kg−1。T3和T4处理土壤Cd含量分别比T2（28.95%）降低了36.53%和30.8%。水/DTPA提取态Cd的浓度也降低了，表明镉的迁移率低修正后。最后，经过wermi修复后，土壤变得更加肥沃和活跃。土壤pH、EC、NO3−-N、速效P和速效K含量增加，而土壤SOM、DOC和NH 4 +-N含量降低。土壤酶活性（包括酸性磷酸酶活性、β-葡萄糖苷酶活性和脲酶活性）均高于蚯蚓处理。微生物群落的操作分类单位（OTU）增加了100-150个单位，且chao 1和Shannon指数较高，说明微生物群落在微生物修复后得到了增强，尤其是EDTA和豆渣处理。因此，蚯蚓单独或与EDTA、豆渣联合应用修复Cd污染土壤是可行的。
The remediation of cadmium (Cd) contaminated soil has become a global problem due to its toxicity to living organisms. In this study, earthworm (Eisenia fetida) alone or combined with EDTA or bean dregs were used for Cd removal from soils. The total and available Cd in soils, soil physicochemical and biological (soil enzyme) properties, Cd accumulation in the earthworm and its antioxidant responses towards Cd, were determined during the 35 days of soil incubation experiment. Our results showed that earthworms were capable of removing Cd from soils, and the remediation process was accelerated by both EDTA and bean dregs. By translocation of Cd from soils, the content of Cd in earthworm steadily increased with the exposure time to 8.11, 12.80, and 9.26 mg kg−1 on day 35 for T2 (earthworm alone), T3 (EDTA enhancement), and T4 (bean dregs enhancement), respectively. Consequently, a great reduction in the Cd contents in soils was achieved in T3 (36.53%) and T4 (30.8%) compared with T2 (28.95%). The concentrations of water/DTPA extractable Cd were also reduced, indicating the low Cd mobility after amendment. Finally, the soil became more fertile and active after wermi-remediation. The soil pH, EC, NO3−-N, available P, and K contents increased, while soil SOM, DOC, and NH4+-N contents were decreased. There were higher soil enzyme activities (including acid phosphatase activity, β-glucosidase activity, and urease activity) among treatments with earthworms. Additionally, the operational taxonomic units (OTUs) increased by 100–150 units, and the higher chao1 and Shannon indexes indicated the enhanced microbial community after wermi-remediation, especially among treatment with EDTA and bean dregs. Therefore, we concluded that earthworms, alone or combined with EDTA and bean dregs, are feasible for the remediation of Cd-contaminated soil.