Wang Xiaoou, Li Jiayin, Wang Meiyan, Zhang Changping, Xue Ming, Xie Haijiao
Key Laboratory of Clean Energy Utilization and Pollutant Control in Tianjin, School of Energy and Environmental Engineering, Hebei University of Technology, China.
Key Laboratory of Clean Energy Utilization and Pollutant Control in Tianjin, School of Energy and Environmental Engineering, Hebei University of Technology, China.
Environ Pollut. 2024 Mar 1;344:123310. doi: 10.1016/j.envpol.2024.123310. Epub 2024 Jan 6.
Disinfection by-products (DBPs) formed from chlorination of antibiotics have greater toxicity than their parent compounds. Herein, this study investigated the biotransformation process of sulfadiazine Cl-DBPs in constructed wetlands (CWs). Results showed that, S atom on sulfonyl group, and N atoms on primary and secondary amine groups were the most reactive sites of sulfadiazine molecule. S1-N4 and S1-C8 of sulfadiazine are the most vulnerable bonds to cleave, followed by C14-N4 and C11-N5 bonds. In the chlorination process, sulfadiazine went through C-N bond cleavage, N-reductive alkylation, halogenation, and desulfonation to produce two aromatic Cl-DBPs. In the biodegradation process in CWs, sulfadiazine Cl-DBPs went through processes mainly including dechlorination, S-N bond cleavage, aniline-NH oxidation, desulfonation, phenol-OH oxidation, benzene ring cleavage, C-N bond cleavage, and β-oxidation of fatty acids under the action of a variety of oxidoreductases and hydrolases, during which a total of ten biodegradation products was identified. Moreover, sulfadiazine affected the biodegradation rather than the adsorption process in CWs. The two aromatic sulfadiazine Cl-DBPs had much higher bioaccumulation potentials than their parent sulfadiazine, but for the ten biodegradation products of sulfadiazine Cl-DBPs in CWs, 70% and almost 100% of them had lower bioaccumulation potentials than sulfadiazine and their parent sulfadiazine Cl-DBPs, respectively. The CWs were effective in reducing the environmental risk of sulfadiazine Cl-DBPs.
抗生素氯化形成的消毒副产物（DBPs）比其母体化合物具有更高的毒性。在此，本研究调查了磺胺嘧啶氯代消毒副产物在人工湿地（CWs）中的生物转化过程。结果表明，磺酰基上的S原子以及伯胺基和仲胺基上的N原子是磺胺嘧啶分子最具反应活性的位点。磺胺嘧啶的S1-N4和S1-C8是最易断裂的键，其次是C14-N4和C11-N5键。在氯化过程中，磺胺嘧啶经历C-N键断裂、N-还原烷基化、卤化和脱磺化反应，生成两种芳香族氯代消毒副产物。在人工湿地的生物降解过程中，磺胺嘧啶氯代消毒副产物在多种氧化还原酶和水解酶的作用下，主要经历脱氯、S-N键断裂、苯胺-NH氧化、脱磺化、酚-OH氧化、苯环裂解、C-N键断裂和脂肪酸β-氧化等过程，在此期间共鉴定出十种生物降解产物。此外，磺胺嘧啶影响人工湿地中的生物降解过程而非吸附过程。两种芳香族磺胺嘧啶氯代消毒副产物的生物累积潜力远高于其母体磺胺嘧啶，但对于人工湿地中磺胺嘧啶氯代消毒副产物的十种生物降解产物，其中70%和几乎100%的生物累积潜力分别低于磺胺嘧啶及其母体磺胺嘧啶氯代消毒副产物。人工湿地对于降低磺胺嘧啶氯代消毒副产物的环境风险具有显著效果。
