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Joseph NK, Koshy VJ, Aravind UK, Aravindakumar CT. Photo-transformation of ofloxacin in natural aquatic conditions: Impact of Indirect photolysis on the product profile and transformation mechanism. CHEMOSPHERE 2024:142484. [PMID: 38830465 DOI: 10.1016/j.chemosphere.2024.142484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/26/2024] [Accepted: 05/28/2024] [Indexed: 06/05/2024]
Abstract
The natural phototransformation of organic pollutants in the environment depends on several water constituents, including inorganic ions, humic substances, and pH. However, the literature information concerning the influence of various water components on the amount of phototransformation and their impact on the development of various transformation products (TPs) is minimal. This study investigated the phototransformation of ofloxacin (OFL), a fluoroquinolone antibiotic, in the presence of various water components such as cations (K+, Na+, Ca2+, NH4+, Mg2+), anions (NO3-, SO42-, HCO3-, CO32-, PO43-), pH, and humic substances when exposed to natural sunlight. The study reveals that neutral pH levels (0.39374 min⁻1) enhance the phototransformation of OFL in aquatic environments. Carbonate, among anions, shows the highest rate constant (2.89966 min⁻1), significantly influencing OFL phototransformation, while all anions exhibit a notable impact. In aquatic environments, indirect phototransformation of OFL, driven by increased reactive oxygen species, expedites light-induced reactions, potentially enhancing OFL phototransformation. A clear difference was visible in the type of transformation products (TPs) formed during direct and indirect photolysis. The impact of indirect photolysis in the product profile was evaluated by examining the unique properties of transformation products (TPs) in direct and indirect photolysis. The primary transformation products were generated by oxidation and cleavage processes directed towards the ofloxacin piperazinyl, oxazine, and carboxyl groups. The toxicity assessment of TPs derived from OFL revealed that among the 26 identified TPs, TP3 (demethylated product), TP7 and TP8 (decarboxylated products), and TP15 (piperazine ring cleaved product) could potentially have some toxicological effects. These findings suggest that the phototransformation of OFL in the presence of various water components is necessary when assessing this antibiotic's environmental fate.
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Affiliation(s)
- Nisha K Joseph
- Inter-University Instrumentation Centre (IUIC), Mahatma Gandhi University (MGU), Kottayam 686560, Kerala, India
| | - Valsamma J Koshy
- Inter-University Instrumentation Centre (IUIC), Mahatma Gandhi University (MGU), Kottayam 686560, Kerala, India
| | - Usha K Aravind
- School of Environmental Studies, Cochin University of Science & Technology (CUSAT), Kochi 682022, Kerala, India
| | - Charuvila T Aravindakumar
- Inter-University Instrumentation Centre (IUIC), Mahatma Gandhi University (MGU), Kottayam 686560, Kerala, India; School of Environmental Sciences, Mahatma Gandhi University (MGU), Kottayam 686560, Kerala, India.
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Ke Y, Jiang J, Mao X, Qu B, Li X, Zhao H, Wang J, Li Z. Photochemical reaction of glucocorticoids in aqueous solution: Influencing factors and photolysis products. CHEMOSPHERE 2023; 331:138799. [PMID: 37119927 DOI: 10.1016/j.chemosphere.2023.138799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/09/2023]
Abstract
Glucocorticoids (GCs), as endocrine disruptors, have attracted widespread attention due to their impacts on organisms' growth, development, and reproduction. In the current study, the photodegradation of budesonide (BD) and clobetasol propionate (CP), as targeted GCs, was investigated including the effects of initial concentrations and typical environmental factors (Cl-, NO2-, Fe3+, and fulvic acid (FA)). The results showed that the degradation rate constants (k) were 0.0060 and 0.0039 min-1 for BD and CP at concentration of 50 μg·L-1, and increased with the initial concentrations. Under the addition of Cl-, NO2-, and Fe3+ to the GCs/water system, the photodegradation rate was decreased with increasing Cl-, NO2-, and Fe3+ concentrations, which were in contrast to the addition of FA. Electron resonance spectroscopy (EPR) analysis and the radical quenching experiments verified that GCs could transition to the triplet excited states of GCs (3GCs*) for direct photolysis under irradiation to undergo, while NO2-, Fe3+, and FA could generate ·OH to induce indirect photolysis. According to HPLC-Q-TOF MS analysis, the structures of the three photodegradation products of BD and CP were elucidated, respectively, and the phototransformation pathways were inferred based on the product structures. These findings help to grasp the fate of synthetic GCs in the environment and contribute to the understanding of their ecological risks.
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Affiliation(s)
- Yifan Ke
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Jingqiu Jiang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, No.12 South Zhongguancun Ave., Haidian District, Beijing, 100081, China
| | - Xiqin Mao
- Dalian Institute for Drug Control, Dalian Food and Drug Administration, Dalian, 116024, China
| | - Baocheng Qu
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116024, China
| | - Xintong Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Hongxia Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
| | - Jingyao Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Zhansheng Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
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