Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, CZ-142 20, Prague 4, Czech Republic; Institute for Environmental Studies, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague 2, Czech Republic.
Technical University of Liberec, Studentská 2, CZ-461 17, Liberec, Czech Republic.
Chemosphere. 2021 Oct;281:130915. doi: 10.1016/j.chemosphere.2021.130915. Epub 2021 May 17.
Abiotic and biotic remediation of chlorinated ethenes (CEs) in groundwater from a real contaminated site was studied using biochar-based composites containing nanoscale zero-valent iron (nZVI/BC) and natural resident microbes/specific CE degraders supported by a whey addition. The material represented by the biochar matrix decorated by isolated iron nanoparticles or their aggregates, along with the added whey, was capable of a stepwise dechlorination of CEs. The tested materials (nZVI/BC and BC) were able to decrease the original TCE concentration by 99% in 30 days. Nevertheless, regarding the transformation products, it was clear that biotic as well as abiotic transformation mechanisms were involved in the transformation process when nonchlorinated volatiles (i.e., methane, ethane, ethene, and acetylene) were detected after the application of nZVI/BC and nZVI/BC with whey. The whey addition caused a massive increase in bacterial biomass in the groundwater samples (monitored by 16S rRNA sequencing and qPCR) that corresponded with the transformation of trichloro- and dichloro-CEs, and this process was accompanied by the formation of less chlorinated products. Moreover, the biostimulation step also eliminated the adverse effect caused by nZVI/BC (decrease in microbial biomass after nZVI/BC addition). The nZVI/BC material or its aging products, and probably together with vinyl chloride-respiring bacteria, were able to continue the further reductive dechlorination of dichlorinated CEs into nonhalogenated volatiles. Overall, the results of the present study demonstrate the potential, feasibility, and environmental safety of this nanobioremediation approach.
采用纳米零价铁（nZVI）/生物炭复合材料和天然土著微生物/特定氯代乙烷（CE）降解菌，辅以乳清添加，对实际污染场地地下水中的氯代乙烷（CEs）进行了生物和非生物修复研究。由孤立铁纳米颗粒或其聚集体修饰的生物炭基质代表的材料，以及添加的乳清，能够逐步脱氯 CE。在 30 天内，测试材料（nZVI/BC 和 BC）能够将原始 TCE 浓度降低 99%。然而，就转化产物而言，当在应用 nZVI/BC 和 nZVI/BC 与乳清后检测到非氯挥发性物质（即甲烷、乙烷、乙烯和乙炔）时，显然涉及生物和非生物转化机制参与转化过程。乳清的添加导致地下水样本中细菌生物量大量增加（通过 16S rRNA 测序和 qPCR 监测），这与三氯和二氯 CE 的转化相对应，并且这一过程伴随着形成较少氯代产物。此外，生物刺激步骤还消除了 nZVI/BC 引起的不利影响（nZVI/BC 添加后微生物生物量减少）。nZVI/BC 材料或其老化产物，可能与氯乙烯呼吸细菌一起，能够将二氯 CE 进一步还原脱氯成非卤化挥发性物质。总体而言，本研究结果表明了这种纳米生物修复方法的潜力、可行性和环境安全性。
