State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
Chemosphere. 2017 Jul;178:432-438. doi: 10.1016/j.chemosphere.2017.03.077. Epub 2017 Mar 23.
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) 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). 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. 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.
雌激素在地表水中的命运主要取决于两个过程，即光降解和生物转化。这两个过程中的每一个过程都具有重要意义，但对这两个过程的组合的研究却很少被探索。在本工作中，系统地研究了天然有机物（NOM）和辣根过氧化物酶（HRP）存在下，同时光化学和酶促过程对 17α-乙炔基雌二醇（EE2）的转化。在模拟阳光照射下，NOM 和 HRP 存在时 EE2 的组合转化速率（0.057 h）明显快于仅 NOM 存在时（0.032 h）。在太湖水实际水样中也观察到了类似的模式。进一步的研究表明，NOM 浓度在 0 到 20 mgC L 范围内对 EE2 的光降解和酶转化有显著影响。NOM 被发现始终能加速 EE2 的光降解，随着浓度的增加而增加。相反，HRP 介导的 EE2 转化速率随着 NOM 浓度的增加而降低。原因可能是 HRP 在高 NOM 浓度的溶液中容易失活。在阳光直射下的环境水平下对 EE2 的转化实验证实了 HRP 在 NOM 存在下对 EE2 降解的重要贡献。结果表明，HRP 介导的氧化是 EE2 和其他同类污染物在水生态环境中的重要归宿。
