Xu Haiyin, Zhao Peiling, Ran Qiyang, Li Wenjuan, Wang Ping, Luo Yuanling, Huang Chao, Yang Xiong, Yin Jingxuan, Zhang Ruiqi
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China; Hunan Hengkai Environmental Protection Science & Technology Investment Co. Ltd, Changsha 410205, China.
Sci Total Environ. 2021 Jun 10;772:145029. doi: 10.1016/j.scitotenv.2021.145029. Epub 2021 Feb 3.
Enhanced electrokinetic remediation (EKR) allows the rapid remediation of heavy metal-contaminated clay, but the impacts of this process on soil micro-ecology have rarely been evaluated. In this study, nitric acid, acetic acid, and EDTA were applied for enhancement of EKR and the effects on Cd removal, soil enzyme activity, and soil bacterial communities (SBCs) were determined. Nitric acid and acetic acid allowed 93.2% and 91.8% Cd removal, respectively, and EDTA treatment resulted in 40.4% removal due to the formation of negatively charged EDTA-Cd complexes, resulting in opposing directions of Cd electromigration and electroosmosis flow and slow electromigration rate caused by low voltage drop. Activities of soil beta-glucosidase, acid phosphatase, and urease, were all reduced by enhanced EKR treatment, especially nitric acid treatment, by 46.2%, 58.8% and 57.7%, respectively. The SBCs were analyzed by high-throughput sequencing and revealed significantly increased diversity for acetic acid treatment, no effect for EDTA treatment, and reduced diversity for nitric acid treatment. Compared with nitric acid and EDTA, acetic acid treatment enhanced EKR for higher Cd removal and improved biodiversity.
强化电动修复（EKR）能够快速修复重金属污染的黏土，但该过程对土壤微生态的影响鲜有评估。本研究中，应用硝酸、乙酸和乙二胺四乙酸（EDTA）强化EKR，并测定其对镉去除、土壤酶活性和土壤细菌群落（SBCs）的影响。硝酸和乙酸处理分别实现了93.2%和91.8%的镉去除率，而EDTA处理因形成带负电荷的EDTA-镉络合物，导致镉电迁移和电渗流方向相反，且低电压降造成电迁移速率缓慢，使得镉去除率为40.4%。强化EKR处理，尤其是硝酸处理，使土壤β-葡萄糖苷酶、酸性磷酸酶和脲酶的活性均降低，降幅分别为46.2%、58.8%和57.7%。通过高通量测序分析SBCs，结果显示乙酸处理的多样性显著增加，EDTA处理无影响，硝酸处理的多样性降低。与硝酸和EDTA相比，乙酸处理强化EKR可实现更高的镉去除率并改善生物多样性。
