Interdisciplinary Toxicology Program, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, USA.
Interdisciplinary Toxicology Program, Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, USA.
J Hazard Mater. 2018 Oct 5;359:241-247. doi: 10.1016/j.jhazmat.2018.07.048. Epub 2018 Jul 11.
Perfluorooctanoic acid (PFOA) can induce undesirable effects to humans and animals and has thus attracted much attention from the public and scientific communities in recent years. Extensive studies have been devoted to exploring PFOA degradation in aqueous phase, while information for that in soil is rather limited. Understanding the transformation of PFOA in soil is important in developing strategies to assess and manage its environmental fate. In this study, we have demonstrated that PFOA can be effectively degraded by enzyme catalyzed oxidative humification reactions (ECOHRs) with a natural organic material, soybean meal, as the mediator. In the presence of soybean meal and laccase, PFOA was degraded 24% in water after 36 days, 40% in soil slurry after 140 days. The water extract of soybean meal contained high concentrations of natural organic mediators and multivalent metal ions, both of which were essential to PFOA degradation by ECOHRs. The ECOHR degradation products of PFOA in soil were identified to be partially fluorinated organic compounds, and the molecular features of the products suggest that the degradation mechanism involves free radical chain reaction processes, which was initiated by direct free radical attacks on the CC bonds in perfluoroalkyl acids.
全氟辛酸（PFOA）可对人类和动物产生不良影响，近年来引起了公众和科学界的广泛关注。人们已经投入了大量的研究来探索 PFOA 在水相中的降解，而有关其在土壤中降解的信息则相当有限。了解 PFOA 在土壤中的转化对于制定评估和管理其环境归宿的策略非常重要。在本研究中，我们已经证明，全氟辛酸可以通过酶催化的氧化腐殖化反应（ECOHRs）有效地降解，而大豆粉作为介体可以促进这一反应。在大豆粉和漆酶存在的情况下，PFOA 在水中经过 36 天降解了 24%，在土壤悬液中经过 140 天降解了 40%。大豆粉的水提取物中含有高浓度的天然有机介体和多价金属离子，这两者都是 ECOHRs 降解 PFOA 所必需的。在土壤中，ECOHR 降解 PFOA 的产物被鉴定为部分氟化的有机化合物，产物的分子特征表明，降解机制涉及自由基链式反应过程，该过程由直接自由基对全氟烷基酸中的 CC 键的攻击引发。
