Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
Ecotoxicol Environ Saf. 2019 Apr 30;171:313-320. doi: 10.1016/j.ecoenv.2018.12.081. Epub 2019 Jan 3.
Photolysis and microbial activity are relatively obvious in shallow, eutrophic waters with low dissolved oxygen content. Ubiquitous humic acid (HA) can act as electron acceptor and be reduced by bacterial under such conditions, and the reduced form of humic acid (RHA) plays an important role in the photolysis contaminants. In this study, anaerobic 17α-ethinylestradiol (EE2) photodegradation was performed along with biodegradation by Shewanella putrefaciens mediated by HA. The mechanism of such coupled photolysis and biodegradation of EE2 was thus elucidated. The removal rate in such coupled degradation in the presence of 10 mgC L of HA at pH 8.0 was greater than that of either photolysis or biodegradation alone. HA which had been reduced in a double-chamber microbial fuel cell showed better promotion to EE2 photodegradation than fresh HA. Reactive species scavenging experiments indicated that hydroxyl radical and excited triplet states of HA were primary contributors to EE2 photodegradation in anaerobic conditions. More of them were produced from RHA than from pristine HA. Besides, the degraded EE2 solutions inhibited the proliferation of MCF-7 human cancer Cells. These findings improve our understanding of the environmental transformation of EE2 in the shallow, anoxic waters.
在溶解氧含量低的浅水富营养化水域中，光解和微生物活性相对明显。在这种条件下，普遍存在的腐殖酸（HA）可以作为电子受体，并被细菌还原，而腐殖酸的还原形式（RHA）在光解污染物中起着重要作用。在本研究中，通过 Shewanella putrefaciens 介导的 HA 进行厌氧 17α-乙炔基雌二醇（EE2）光降解和生物降解。从而阐明了 EE2 这种偶联光解和生物降解的机制。在 pH 值为 8.0 时，在 10mgC/L 的 HA 存在下的偶联降解中，去除率大于单独光解或生物降解。在双室微生物燃料电池中还原的 HA 对 EE2 光降解的促进作用优于新鲜 HA。活性物质清除实验表明，在厌氧条件下，羟基自由基和 HA 的激发三重态是 EE2 光降解的主要贡献者。它们主要是从 RHA 中产生的，而不是从原始 HA 中产生的。此外，降解后的 EE2 溶液抑制了 MCF-7 人癌细胞的增殖。这些发现提高了我们对浅水缺氧水域中 EE2 的环境转化的理解。
