Transformation of 17α-ethinylestradiol by simultaneous photo-enzymatic process in Humic water. (July 2017)

• Record Type: Journal Article
• Authors: Yang, Yun; Li, Jianhua; Lu, Kun; Shi, Huanhuan; Gao, Shixiang
• Is Part Of: Chemosphere. Volume 178(2017)
• Page Start: 432
• Page End: 438
• Publication Date: 2017-07
• Subjects: Estrogens -- Combined transformation -- Sunlight -- Natural organic matter -- Horseradish peroxidase; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.03.077
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The fate of estrogens in surface water is mainly dependent on two processes, i.e. photodegradation and biotransformation. Each of the separate process is invariably of interest, but research on the combination of the two processes has rarely been explored. In the present work, the transformation of 17α-ethinylestradiol (EE2) by simultaneous photochemical and enzymatic process in water was systematically investigated. The combined transformation rate of EE2 (0.057 h −1 ) in the presence of natural organic matter (NOM) and horseradish peroxidase (HRP) under simulated sunlight irradiation was markedly faster than that in the presence of NOM only (0.032 h −1 ). Similar pattern was also observed in real water matrix sampled from Taihu Lake. Further study revealed that the photodegradation and enzymatic transformation of EE2 were dramatically affected by NOM concentrations ranging from 0 to 20 mgC L −1 . NOM was found to invariably accelerate the photodegradation of EE2 with increasing concentration. On the contrary, the transformation rate of EE2 mediated by HRP was decreased along with the increase of NOM concentration. The reason may be that HRP was prone to be inactivated in solution with high NOM concentration. The transformation experiment of EE2 at ambient level under sunlight confirmed the significant contribution of HRP to the degradation of EE2 in the presence of NOM. The results indicated that oxidation mediated by HRP was an essential fate of EE2 and other congener contaminants in aquatic environment. Graphical abstract: Highlights: HRP-mediated degradation was an essential fate of EE2 in simulated surface water. Half-life of EE2 decreased from 21.7 h with NOM to 12.2 h with NOM and HRP. Photolysis rate was invariably accelerated with increasing NOM concentration. Enzymatic transformation was inversely related to NOM concentration. HRP markedly enhanced the transformation of EE2 in real matrix.