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Ledezma-Espinoza A, Challis JK, Roa-Gutierrez F, Sánchez-Kopper A, Castellón E, Wong CS. Photolysis of the nonsteroidal anti-inflammatory drug sulindac: elucidation of kinetic behaviour and photodegradation pathways in water. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1405-1417. [PMID: 34553727 DOI: 10.1039/d1em00167a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Non-steroidal anti-inflammatory drugs are recognized widely as emerging contaminants. Sulindac has received additional attention as a prodrug in cancer treatment and because of its detection in drinking water and wastewaters. Nevertheless, there is limited knowledge about its kinetic behaviour and fate in the aquatic environment. In this work, the direct photolysis of sulindac, in which photochemical reactions were monitored and phototransformation products identified, was investigated under prolonged periods using UV-A and UV-B radiation and pH conditions (2 and 7) to evaluate the effect of the protonation state and the efficiency of the photolytic process. A novel kinetic mechanism has been proposed in which sulindac exhibits a consecutive reaction pathway, with pseudo-first order kinetics for rapid and reversible Z to E isomerization. Once photoequilibrium was reached, second-order degradation of the isomers in the presence of the new photodegradation products was observed. Photochemical transformation was faster under UV-B irradiation and lower pH, which suggests greater persistence of sulindac at more relevant environmental conditions of UV-A and pH 7. Two novel and major byproducts were identified, corresponding to the oxidative cleavage of the alkene exo to the indene system. The degradation pathway is mainly photoinduced, enhanced by acidic conditions and presumes the double bond as the most reactive site for the parent compound. This research demonstrates an approach for determining kinetics of compounds under challenging conditions, including, absorption from multiple electronic transitions, photoinduced products with unknown extinction coefficients, concentration dependence, photoinduced sensitizing intermediates, and speciation effects. Our work greatly improves our understanding of the degradation process of sulindac and will contribute to exposure assessments and treatment methodologies for this compound in impacted waters.
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Affiliation(s)
- Aura Ledezma-Espinoza
- Centro de Investigación y de Servicios Químicos y Microbiológicos (CEQIATEC), School of Chemistry, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica.
| | - Jonathan K Challis
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada
| | - Floria Roa-Gutierrez
- Centro de Investigación y de Servicios Químicos y Microbiológicos (CEQIATEC), School of Chemistry, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica.
| | - Andrés Sánchez-Kopper
- Centro de Investigación y de Servicios Químicos y Microbiológicos (CEQIATEC), School of Chemistry, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica.
| | - Erick Castellón
- School of Chemistry, Materials Science and Engineering Research Center (CICIMA), Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - Charles S Wong
- Centro de Investigación y de Servicios Químicos y Microbiológicos (CEQIATEC), School of Chemistry, Instituto Tecnológico de Costa Rica, Cartago 159-7050, Costa Rica.
- Southern California Coastal Water Research Project Authority, Costa Mesa, CA 92626, USA
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Zhao J, Zhou Y, Li C, Xie Q, Chen J, Chen G, Peijnenburg WJGM, Zhang YN, Qu J. Development of a quantitative structure-activity relationship model for mechanistic interpretation and quantum yield prediction of singlet oxygen generation from dissolved organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 712:136450. [PMID: 31931195 DOI: 10.1016/j.scitotenv.2019.136450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/29/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Singlet oxygen (1O2) is capable of degrading organic contaminants and inducing cell damage and inactivation of viruses. It is mainly generated through the interaction of dissolved oxygen with excited triplet states of dissolved organic matter (DOM) in natural waters. The present study aims at revealing the underlying mechanism of 1O2 generation and providing a potential tool for predicting the quantum yield of 1O2 (Φ1O2) generation from DOM by constructing a quantitative structure-activity relationship (QSAR) model. The determined Φ1O2 values for the selected DOM-analogs range from (0.54 ± 0.23) × 10-2 to (62.03 ± 2.97) × 10-2. A QSAR model was constructed and was proved to have satisfactory goodness-of-fit and robustness. The QSAR model was successfully used to predict the Φ1O2 of Suwannee River fulvic acid. Mechanistic interpretation of the descriptors in the model showed that hydrophobicity, molecular complexity and the presence of carbonyl groups in DOM play crucial roles in the generation of 1O2 from DOM. The presence of other heteroatoms besides O, such as N and S, also affects the generation of 1O2. The results of this study provide valuable insights into the generation of 1O2 from DOM in sunlit natural waters.
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Affiliation(s)
- Jianchen Zhao
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China
| | - Yangjian Zhou
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China
| | - Chao Li
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China
| | - Qing Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Guangchao Chen
- Institute of Environmental Sciences, Leiden University, Leiden, the Netherlands
| | - Willie J G M Peijnenburg
- Institute of Environmental Sciences, Leiden University, Leiden, the Netherlands; National Institute of Public Health and the Environment (RIVM), Center for Safety of Substances and Products, Bilthoven, the Netherlands
| | - Ya-Nan Zhang
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China.
| | - Jiao Qu
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China.
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Zhou Y, Zhao J, Zhang YN, Qu J, Li C, Qin W, Zhao Y, Chen J, Peijnenburg WJGM. Trace amounts of fenofibrate acid sensitize the photodegradation of bezafibrate in effluents: Mechanisms, degradation pathways, and toxicity evaluation. CHEMOSPHERE 2019; 235:900-907. [PMID: 31299703 DOI: 10.1016/j.chemosphere.2019.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Effluent organic matter (EfOM), which is composed of background natural organic matter (NOM), soluble microbial degradation products, and trace amounts of organic pollutants, can play an important role in the photodegradation of emerging pollutants in the effluent. In this study, the impact of organic pollutants, using fenofibrate acid (FNFA) as a representative, on the photodegradation of emerging contaminants, using bezafibrate (BZF) as a representative, in effluents was investigated. It is found that BZF undergo fast degradation in the presence of FNFA although BZF is recalcitrant to degradation under simulated sunlight irradiation. The promotional effect of FNFA is due to the generation of singlet oxygen (1O2) and hydrated electrons (e-aq). Based on the structures of the identified intermediates, 1O2 initiated oxidation and e-aq initiated reduction reactions were the main photodegradation pathways of BZF in the effluents. The toxicity of the main photodegradation intermediates for BZF and FNFA was higher than that of the parent compounds, and the acute toxicity increased during simulated sunlight irradiation. The results demonstrated that trace amounts of organic compounds in EfOM can play an important role in sensitizing the photodegradation of some emerging pollutants in the effluent.
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Affiliation(s)
- Yangjian Zhou
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Jianchen Zhao
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Ya-Nan Zhang
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China.
| | - Jiao Qu
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China.
| | - Chao Li
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Weichao Qin
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Yahui Zhao
- State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun, 130117, China
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Willie J G M Peijnenburg
- Institute of Environmental Sciences, Leiden University, Leiden, the Netherlands; National Institute of Public Health and the Environment (RIVM), Center for Safety of Substances and Products, Bilthoven, the Netherlands
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Zhang YN, Zhou Y, Qu J, Chen J, Zhao J, Lu Y, Li C, Xie Q, Peijnenburg WJGM. Unveiling the important roles of coexisting contaminants on photochemical transformations of pharmaceuticals: Fibrate drugs as a case study. JOURNAL OF HAZARDOUS MATERIALS 2018; 358:216-221. [PMID: 29990809 DOI: 10.1016/j.jhazmat.2018.06.068] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Pharmaceuticals are a group of ubiquitous emerging pollutants, many of which have been shown to undergo efficient photolysis in the environment. Photochemically produced reactive intermediates (PPRIs) sensitized by the pharmaceuticals in sunlit natural waters may induce photodegradation of coexisting compounds. In this study, the roles of coexisting contaminants on the phototransformation of pharmaceuticals were unveiled with the fibrate drugs gemfibrozil (GMF), fenofibrate (FNF), and fenofibric acid (FNFA) as model compounds. GMF undergoes initial concentration dependent photodegradation due to the involvement of singlet oxygen (1O2) initiated self-sensitized photolysis, and undergoes pH dependent photodegradation due to dissociation and hydroxyl radical (OH) generation. The decarboxylated intermediates of GMF and coexisting FNFA significantly accelerated the photodegradation of GMF. The promotional effects of the decarboxylated intermediates are attributed to generation of PPRIs, e.g. 1O2, superoxide (O2-), that subsequently react with GMF. Besides, FNFA can also promote the photodegradation of GMF through the electron transfer reaction from ground state GMF to excited state FNFA, leading to the formation of decarboxylated intermediates. The formed intermediates can subsequently also facilitate GMF photodegradation. The results presented here provided valuable novel insights into the effects of coexisting contaminants on the photodegradation of pharmaceuticals in polluted waters.
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Affiliation(s)
- Ya-Nan Zhang
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Yangjian Zhou
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Jiao Qu
- School of Environment, Northeast Normal University, Changchun 130117, China.
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jianchen Zhao
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Ying Lu
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Chao Li
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Qing Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Willie J G M Peijnenburg
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands; National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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