State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, China.
Environ Pollut. 2019 Mar;246:782-789. doi: 10.1016/j.envpol.2018.12.098. Epub 2019 Jan 2.
Natural dissolved organic matter (DOM) produced in algal blooms and overgrowths of macrophyte changes the elimination and ecotoxicity of estrogens in freshwater lakes. The complexation of 17α-ethinylestradiol (EE2) and various DOMs, including the water- and sediment-derived DOMs from the algal-dominant zone in Lake Taihu (TW and TS, respectively) and the macrophyte-dominant zone in Poyang Lake (PW and PS, respectively), and the humic acid (HA), was investigated along with the subsequent effects on EE2 biodegradation. Dialysis equilibrium experiments showed that binding to DOM significantly decreased the freely soluble concentrations of EE2. The binding capacity of the five DOMs followed the order of PW < TW < PS ≈ TS < HA. A negative correlation was found between the organic-carbon-normalized sorption coefficient (logK) and the absorption ratio (E/E) of DOM, indicating that the large sized, aromatic molecules were involved in the complexation. The reduced freely soluble concentrations of EE2 did not inhibit its biodegradation by an EE2-degrading strain, Rhodobacter blasticus. Conversely, the autochthonous-dominated water-derived DOMs stimulated a more extensive biodegradation of EE2 than the sediment-derived DOMs, and the existence of HA resulted in the smallest increase in EE2 biodegradation. The promoting effect was associated with the increased concentration, activity, and transforming rate of R. blasticus by the bioavailable components in DOM. The present study suggests that the significant impact of natural DOM should be fully considered when assessing the fate and ecological risks of estrogens in eutrophic waters.
藻类大量繁殖和水生植物过度生长所产生的天然溶解性有机物（DOM）会改变淡水湖中雌激素的消除和生态毒性。研究了 17α-乙炔基雌二醇（EE2）与各种 DOM 的络合作用，包括来自太湖藻优势区的水和沉积物 DOM（分别为 TW 和 TS）和鄱阳湖草优势区的 DOM（分别为 PW 和 PS），以及腐殖酸（HA），并考察了它们对 EE2 生物降解的后续影响。透析平衡实验表明，DOM 的结合显著降低了 EE2 的自由溶解浓度。五种 DOM 的结合能力顺序为 PW< TW< PS≈ TS< HA。DOM 的有机碳归一化吸附系数（logK）与吸收比（E/E）之间呈负相关，表明较大尺寸、芳香族分子参与了络合作用。EE2 的自由溶解浓度降低并没有抑制 EE2 降解菌 Rhodobacter blasticus 对 EE2 的生物降解。相反，源自天然的水相 DOM 比源自沉积物的 DOM 更能促进 EE2 的广泛生物降解，而 HA 的存在则导致 EE2 生物降解的增加最小。促进作用与 DOM 中生物可利用成分对 Rhodobacter blasticus 的浓度、活性和转化速率的增加有关。本研究表明，在评估富营养化水中雌激素的命运和生态风险时，应充分考虑天然 DOM 的显著影响。
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