Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China.
Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China.
J Hazard Mater. 2022 Aug 15;436:129190. doi: 10.1016/j.jhazmat.2022.129190. Epub 2022 May 21.
Polychlorinated biphenyls (PCBs) as typical halogenated persistent organic pollutants are widely distributed in natural environments, and can be enriched and magnified in organisms via food webs. It is consequently urgent and necessary to develop techniques to completely remove these persistent organohalides. In this study, we developed a process (Bio-RD-PAOP) by integrating microbial reductive dechlorination (Bio-RD) with subsequent persulfate activation and oxidation process (PAOP) for effective remediation of PCBs. Results showed the synergistic combination of advantages of Bio-RD and PAOP in dechlorination of higher-chlorinated PCBs and of PAOP in degradation/mineralization of lower-chlorinated PCBs, respectively. For the PAOP, both experimental evidences and theoretical calculations suggested that degradation rate and efficiency decreased with the increased PCB chlorine numbers. Relative to the Bio-RD and PAOP, Bio-RD-PAOP had significantly higher PCB removal efficiencies, of which values were PCB congener-specific. For example, removal efficiency of Bio-RD-PAOP in removing PCB88 is 2.50 and 1.86 times of that of Bio-RD and PAOP, respectively. In contrast, the efficiency is 1.66 and 3.35 times of Bio-RD and PAOP, respectively, for PCB180 removal. The PAOP-derived oxidizing species (mainly sulfate free radical) significantly decreased microbial abundance, particularly of the organohalide-respiring Dehalococcoides. Notably, co-existence of other microorganisms alleviated the inhibitive effect of oxidizing species on the Dehalococcoides, possibly due to formation of microbial flocs or biofilm. This study provided a promising strategy for extensive remediation of organohalide-contaminated sites, as well as new insight into impact of PAOP-derived oxidizing species on the organohalide-respiring community.
多氯联苯（PCBs）作为典型的卤代持久性有机污染物，广泛分布于自然环境中，并可通过食物网在生物体内富集和放大。因此，开发完全去除这些持久性有机卤化物的技术是当务之急。本研究通过整合微生物还原脱氯（Bio-RD）与后续过硫酸盐活化和氧化过程（PAOP），开发了一种处理 PCBs 的工艺（Bio-RD-PAOP）。结果表明，Bio-RD 和 PAOP 的协同组合分别具有脱除高氯代 PCBs 的优势，以及 PAOP 降解/矿化低氯代 PCBs 的优势。对于 PAOP，实验证据和理论计算均表明，降解速率和效率随 PCB 氯原子数的增加而降低。相对于 Bio-RD 和 PAOP，Bio-RD-PAOP 对 PCBs 的去除效率显著提高，且具有特定的同系物特异性。例如，Bio-RD-PAOP 去除 PCB88 的去除效率分别是 Bio-RD 和 PAOP 的 2.50 倍和 1.86 倍。相比之下，Bio-RD-PAOP 去除 PCB180 的效率分别是 Bio-RD 和 PAOP 的 1.66 倍和 3.35 倍。PAOP 衍生的氧化物种（主要是硫酸根自由基）显著降低了微生物的丰度，特别是有机卤化物呼吸脱氯菌（Dehalococcoides）的丰度。值得注意的是，其他微生物的共存缓解了氧化物种对 Dehalococcoides 的抑制作用，这可能是由于形成了微生物絮体或生物膜。本研究为广泛修复有机卤化物污染场地提供了一种有前景的策略，并为 PAOP 衍生的氧化物种对有机卤化物呼吸群落的影响提供了新的见解。
