摘要
在复杂冰/水环境体系中,抗生素与共存污染物之间的作用机制及抗生素的光敏化机理值得深入探究.本文对比研究了冰中与水中典型抗生素(诺氟沙星NORF、磺胺氯哒嗪SCP和土霉素OTC)对共存污染物甲砜霉素(TAP)的光敏化降解机理以及光转化过程中的毒性演变机制.发现3种抗生素在冰/水中均具有类似于溶解性有机质的光化学活性,可以引发TAP的间接光解,且每种抗生素光敏剂在冰中的敏化作用均大于水中.基于活性物种(RS)淬灭实验与探针实验,水中光敏剂光致生成的羟基自由基(·OH)、单线态氧(^(1)O_(2))和三重激发态(^(3)P^(*))等3种RS对TAP敏化降解的贡献均大于冰中.冰/水中光敏剂生成的RS稳态浓度为^(1)O_(2)>·OH>^(3)P^(*),这与RS的寿命有关.采用高效液相色谱-串联质谱(HPLC-MS/MS)鉴定了9种产物,发现TAP在冰/水中具有相同的转化途径,主要涉及光致脱氯、光氧化以及甲砜基脱除等反应.毒性实验表明,冰/水中TAP对Vibrio fischeri表现为光修饰毒性;ECOSAR软件证实多数产物的毒性高于母体化合物.本研究揭示了冰/水中典型抗生素光敏化降解共存污染物的机理,有助于更好地理解寒冷地区共存污染物的光化学归趋与风险.
In complex ice/water environments,antibiotics coexist with other pollutants,and the related mechanisms deserve further exploration for their interaction and photo-sensitized degradation.This study demonstrated an in-depth comparative study on the photodegradation mechanisms of the pollutant(thiamphenicol,TAP)sensitized by typical antibiotics(norfloxacin(NORF),sulfachloropyridazine(SCP),and oxytetracycline(OTC))in ice and in water,as well as explored the toxicity changes and mechanisms of the reaction solutions during the photo-transformation process.The three antibiotics all exhibited photochemical activity analogous to dissolved organic matter in ice and in water,which induced the indirect photodegradation of TAP.The sensitization effect of each antibiotic photosensitizer in ice was greater than that in water.Based on the reactive-species(RS)quenching experiments and probe experiments,it was indicated that the contribution of the three RS(hydroxyl radical·OH,singlet oxygen ^(1)O_(2),and excited triplet state ^(3)P^(*))was higher in water than in ice.The steady state concentrations of RS generated by the photosensitizers in ice and in water were as follows:^(1)O_(2)>·OH>^(3)P^(*),which could be related to the lifetime of RS.Furthermore,nine products were identified using HPLC-MS/MS,and it was found that TAP presented the same photo-transformation pathways in ice and in water,mainly involving photo-dechlorination,photo-oxidation and demethylsulfonyl.In addition,toxicity tests showed that TAP in ice/water exhibited photo-modified toxicity towards Vibrio fischeri.The ECOSAR software confirmed that the toxicity of most products was higher than that of the parent compound.This study reveals the mechanism of photodegradation of the pollutant sensitized by typical antibiotics in ice and in water,which contributes to a better understanding of the photochemical fate and risk of these coexisting pollutants in cold regions.
作者
王思源
葛林科
陆隽鹤
张蓬
张静
朱超
Siyuan Wang;Linke Ge;Junhe Lu;Peng Zhang;Jing Zhang;Chao Zhu(School of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China;College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China)
出处
《中国科学:化学》
北大核心
2025年第7期2132-2141,共10页
SCIENTIA SINICA Chimica
基金
国家自然科学基金(编号:21976045,22076112)
陕西省重点研发计划(编号:2024SF-YBXM-567)
中国国家留学基金(编号:202308610123)资助项目。
关键词
冰环境光化学
水环境光化学
抗生素
甲砜霉素
活性物种
光敏化降解
ice photochemistry
aqueous photochemistry
antibiotics
thiamphenicol
reactive species
photo-sensitized degradation
