Aquatic photo-transformation and enhanced photoinduced toxicity of ionizable tetracycline antibiotics  

作　　者：Linke Ge Jinshuai Zheng Crispin Halsall Chang-Er Chen Xuanyan Li Shengkai Cao Peng Zhang 

机构地区：[1]School of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China [2]Lancaster Environment Centre,Lancaster University,Lancaster LA14YQ,UK [3]Environmental Research Institute/School of Environment,South China Normal University,Guangzhou 510006,China

出　　处：《Frontiers of Environmental Science & Engineering》2024年第11期111-120,共10页环境科学与工程前沿（英文）

基　　金：supported by the Key Research and Development Program of Shaanxi Province(No.2024SF-YBXM-567);the National Natural Science Foundation of China(Nos.21976045 and 22076112);the China Scholarship Council(CSC)Scholarship(No.202308610123);the Shaanxi Key Laboratory of Environmental Monitoring and Forewarning of Trace Pollutants(No.SHJKFJJ202318).

摘　　要：Most antibiotics contain ionizable groups that undergo acid-base dissociation giving rise to diverse dissociated forms in aquatic systems depending on the pH of the system.In sunlit surface waters,photochemical transformation plays a crucial role in determining the fate of antibiotics.This study presents a comprehensive examination of the photo-transformation degradation kinetics,pathways and photoinduced toxicity of three widely detected tetracyclines(TCs):tetracycline(TC),oxytetracycline(OTC),and chlortetracycline(CTC).Under simulated sunlight(λ>290 nm),their apparent photolysis followed pseudo-first-order kinetics,with rate constants significantly increasing from H_(2)TCs^(0)to TCs^(2–).Through competition kinetic experiments and matrix calculations,it was found that the anions HTCs–or TCs^(2–)(pH~8–10)were more reactive toward hydroxyl radicals(•OH),while TCs^(2–)(pH~10)reacted the fastest with singlet oxygen(^(1)O_(2)).Considering the dissociated species,the total environmental photo-transformation half-lives of TCs were determined,revealing a strong dependence on the water pH and seasonal variation in sunlight.Generally,apparent photolysis was the dominant photochemical process,followed by^(1)O_(2)and•OH oxidation.Different transformation pathways for the three reactions were determined based on the key photoproducts identified using HPLC-MS/MS.Toxicity tests and ECOSAR software calculations confirmed that the intermediates produced by the•OH and 1O_(2)photo-oxidation processes were more toxic than the parent compounds.These findings significantly enhance our understanding of the complex photochemical fate and associated risks of TCs in aqueous environments.

关 键 词：TETRACYCLINES DISSOCIATION Photodegradation kinetics Reactive oxygen species Transformation products RISKS 

分 类 号：X52[环境科学与工程—环境工程]