Federal Institute of Hydrology, Department of Aquatic Chemistry, 56068, Koblenz, Germany.
Federal Institute of Hydrology, Department of Aquatic Chemistry, 56068, Koblenz, Germany.
Water Res. 2021 Jan 1;188:116515. doi: 10.1016/j.watres.2020.116515. Epub 2020 Oct 13.
Previous studies have shown the high ecotoxicological potential of progestogens (PGs) on the reproductive system of aquatic organisms. Yet the ubiquitous presence of several PGs in wastewater treatment plant (WWTP) effluents indicates an incomplete removal during treatment. To investigate the fate and behavior of PGs during biological wastewater treatment, nine commonly used PGs were incubated in aerobic lab-scale degradation experiments with activated sludge taken from a municipal WWTP. The degradation kinetics revealed a fast removal after 48 h for most of the compounds. Cyproterone acetate and dienogest were the most recalcitrant of the analyzed steroids with half-lives of 8.65 h and 4.55 h, respectively. Thus, only moderate removals of these PGs can be predicted in full-scale WWTPs. Moreover, numerous transformation products (TPs) were detected via high-resolution mass spectrometry. Hydrogenation or dehydrogenation of ring A and non-selective hydroxylations of 17α-hydroxyprogesterone derivatives (medroxyprogesterone acetate, chlormadinone acetate, cyproterone acetate) as well as for 19-nortestosterone derivatives (dienogest, norethisterone acetate, etonogestrel) were observed as major transformation reactions. Seven of the identified TPs were confirmed by reference standards. The biodegradation of cyproterone acetate revealed an almost quantitative transformation to 3α‑hydroxy cyproterone acetate which is reported to be genotoxic. In a comparative evaluation of the TPs formed and the steroid structure, it was observed that molecular structure played a role in the inhibition of several transformation reactions, explaining the increased recalcitrance of these compounds. In addition, aromatization of the steroid ring A was identified for the 19-nortestosterone derivatives leading to the formation of estrogen-like TPs. For instance, the degradation of norethisterone acetate led to the formation of 17α-ethinylestradiol, a well-known and very potent synthetic estrogen. The evidence of the conversion of progestogenic to estrogenic compounds and the formation of potentially hazardous TPs indicates the need of a more comprehensive environmental risk assessment for synthetic steroids. Two of the newly identified TPs (3α-hydroxy cyproterone acetate and ∆9,11-dehydro-17α-cyanomethyl estradiol) were detected in WWTP effluents for the first time.
先前的研究表明,孕激素(PGs)对水生生物的生殖系统具有很高的生态毒性。然而,由于污水处理厂(WWTP)废水中普遍存在多种 PGs,这表明在处理过程中没有完全去除。为了研究 PGs 在生物废水处理过程中的归宿和行为,将 9 种常用的 PGs 与取自城市 WWTP 的活性污泥一起在好氧实验室规模降解实验中进行孵育。降解动力学表明,大多数化合物在 48 小时后迅速去除。醋酸环丙孕酮和地诺孕素是分析类固醇中最难降解的,半衰期分别为 8.65 小时和 4.55 小时。因此,在全规模 WWTP 中只能预测这些 PGs 的适度去除。此外,还通过高分辨率质谱检测到许多转化产物(TPs)。通过对 A 环的加氢或脱氢以及对 17α-羟孕酮衍生物(醋酸甲羟孕酮、醋酸氯地孕酮、醋酸环丙孕酮)和 19-去甲睾酮衍生物(地诺孕素、醋酸炔诺酮、依托孕烯)的非选择性羟基化反应观察到主要的转化反应。通过参考标准,确认了其中 7 个鉴定的 TPs。醋酸环丙孕酮的生物降解几乎完全转化为 3α-羟基环丙孕酮,据报道该物质具有遗传毒性。在对形成的 TPs 和类固醇结构进行比较评估时,观察到分子结构在抑制几种转化反应中起作用,这解释了这些化合物抗降解性增加的原因。此外,还发现 19-去甲睾酮衍生物的类固醇 A 环芳构化导致形成类似雌激素的 TPs。例如,醋酸炔诺酮的降解导致形成 17α-乙炔基雌二醇,这是一种众所周知的、非常有效的合成雌激素。孕激素向雌激素化合物转化以及形成潜在有害 TPs 的证据表明,需要对合成类固醇进行更全面的环境风险评估。首次在 WWTP 废水中检测到两种新鉴定的 TPs(3α-羟基环丙孕酮和 ∆9,11-去氢-17α-氰甲基雌二醇)。