Tisler Selina, Liang Chuanzhou, Carvalho Pedro N, Bester Kai
Department of Environmental Science, Aarhus University, Frederiksborgvej 399, Roskilde 4000, Denmark.
Department of Environmental Science, Aarhus University, Frederiksborgvej 399, Roskilde 4000, Denmark; WATEC - Centre for Water Technology, Aarhus University, Ny Munkegade 120, Aarhus 8000, Denmark.
Sci Total Environ. 2021 Mar 20;761:143228. doi: 10.1016/j.scitotenv.2020.143228. Epub 2020 Oct 24.
100 ethylene oxide (EO)/propylene oxide (PO) copolymer precursor and metabolites were detected in wastewater effluents. The homopolymers of EO and PO as well as the EO/PO copolymers are widely used as surfactants, e.g., for the production of cosmetics, pharmaceuticals and lubricants. Concomitantly, these compounds are discharged into the wastewater and the environmental fate of the PO homopolymers, also called polypropylene glycols (PPGs), and EO/PO copolymers is mostly unknown. In the present study, we identified hitherto unknown copolymer EO/PO homologous series and their metabolites in wastewater effluent. The identified compounds occur in homologous series and consist of PPGs and EO/PO copolymers, and their carbonylated, carboxylated and dicarboxylated metabolites. MBBR lab incubations of PPGs and EO/PO copolymers showed the successive degradation by cleavage of individual PO and EO groups, with high removal (>90%) in the initial 8 h for most of the copolymers. Carbonylated and carboxylated metabolites were degraded within 40 h. EO/PO copolymers with a higher number of EO and PO units showed a higher removal in MBBR and conventional activated sludge wastewater treatment plants. Polymers with lower molecular weight were initially formed by degradation of the EO/PO polymers. The mono-carboxylated metabolites were also detected in surface waters. Overall, our results provide new knowledge about degradation pathways of PO containing compounds and show the hitherto unnoticed occurrence of EO/PO copolymers and metabolites in the water cycle.
在废水排放物中检测到了100种环氧乙烷（EO）/环氧丙烷（PO）共聚物前体及其代谢产物。EO和PO的均聚物以及EO/PO共聚物被广泛用作表面活性剂，例如用于生产化妆品、药品和润滑剂。与此同时，这些化合物被排放到废水中，而PO均聚物（也称为聚丙二醇，PPGs）和EO/PO共聚物在环境中的归宿大多未知。在本研究中，我们在废水排放物中鉴定出了迄今未知的共聚物EO/PO同系物系列及其代谢产物。所鉴定的化合物以同系物系列形式存在，由PPGs和EO/PO共聚物及其羰基化、羧基化和二羧基化代谢产物组成。对PPGs和EO/PO共聚物进行的MBBR实验室培养显示，通过单个PO和EO基团的裂解实现了连续降解，大多数共聚物在最初8小时内的去除率很高（>90%）。羰基化和羧基化代谢产物在40小时内被降解。含有较多EO和PO单元的EO/PO共聚物在MBBR和传统活性污泥废水处理厂中的去除率更高。较低分子量的聚合物最初是由EO/PO聚合物降解形成的。在地表水中也检测到了单羧基化代谢产物。总体而言，我们的结果提供了关于含PO化合物降解途径的新知识，并揭示了水圈中迄今未被注意到的EO/PO共聚物及其代谢产物的存在情况。
