1
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Liao M, Li Y, Chen X, Ding S, Su S, Sun W, Gan Z. Photodegradation of anthelmintic drugs under natural sunlight and simulated irradiation: kinetics, mechanisms, transformation products, and toxicity. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:8828-8841. [PMID: 38182950 DOI: 10.1007/s11356-023-31778-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/26/2023] [Indexed: 01/07/2024]
Abstract
Albendazole (ALB) and bithionol (BIT) are two anthelmintic drugs (ADs) with high consumption from benzimidazole group and diphenylsulfide group, respectively. However, information on the transformation of the two anthelmintics under environmental condition is scare. Therefore, in the present study, we investigated the natural attenuation of the two ADs in the aquatic environment, including biodegradation, hydrolysis, and direct and indirect photodegradation. The direct photodegradation occupied a vast portion among other degradation pathways of the two ADs in natural water, with near-surface summer half-lives of 0.272-0.387 h and 0.110-0.520 h for ALB and BIT, respectively. Suspended particles in water were found to facilitate the photodegradation of the two ADs. Study on the indirect photodegradation demonstrated the positive roles of singlet oxygen (1O2) and excited triplet dissolved organic matter (3DOM*) in the photolysis of the two ADs, whereas the hydroxyl radical (•OH) affected little on the overall photodegradation procedures of ALB due to the scavenging effect of HCO3-. Dual effects of DO, DOM, HCO3-, NO3-, and NO2- on the photodegradation of ALB and BIT were perceived. Transformation intermediates (TIs) of the two ADs during photodegradation were analyzed by UHPLC-QTOF-MS. Six TIs of ALB were identified, including a broad-spectrum fungicide carbendazim and another common AD ricobendazole. Two TIs of BIT yielded from dechlorination were also detected. Probable transformation mechanism and predicted aquatic ecotoxicity based on the identified TIs were unveiled.
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Affiliation(s)
- Mengxi Liao
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Yiwen Li
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, China
| | - Xi Chen
- SCIEX, Analytical Instrument Trading Co., Shanghai, 200335, China
| | - Sanglan Ding
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Shijun Su
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Weiyi Sun
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Zhiwei Gan
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
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2
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Zhang S, Xie Y, Manoli K, Ji Y, Yu X, Feng M. Degradation of methotrexate by unactivated and solar-activated peroxymonosulfate in water: Moiety-specific reaction kinetics and transformation product-associated risks. WATER RESEARCH 2023; 246:120741. [PMID: 37864882 DOI: 10.1016/j.watres.2023.120741] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/08/2023] [Accepted: 10/12/2023] [Indexed: 10/23/2023]
Abstract
Anticancer drugs have raised worldwide concern owing to their ubiquitous occurrence and ecological risks, necessitating the development of efficient removal strategies in water and wastewater treatment. Although peroxymonosulfate (PMS) is known to be a promising chemical in water decontamination, limited information is available regarding the removal efficiency of anticancer drugs by PMS and solar/PMS systems. This study first reports the moiety-specific reaction kinetics and mechanisms of methotrexate (MTX), an anticancer drug with widespread attention, by PMS (unactivated) and solar-activated PMS in water. It was found that MTX abatement by the direct PMS oxidation followed second-order kinetics, and the pH-dependent rate constants increased from 0.4 M-1 s-1 (pH 5.0) to 1.3 M-1 s-1 (pH 8.0), with a slight decrease to 1.1 M-1 s-1 at pH 9.0. The presence of chloride and bromide exerted no obvious influence on the removal of MTX by PMS. Furthermore, the chemical reactivity of MTX and its seven substructures with different reactive species was evaluated, and the degradation contributions of the reactive species involved were quantitatively analyzed in the solar/PMS system. The product analysis suggested similar reaction pathways of MTX by PMS and solar/PMS systems. The persistence, bioaccumulation, and toxicity of the transformation products were investigated, indicating treatment-driven risks. Notably, MTX can be removed efficiently from both municipal and hospital wastewater effluents by the solar/PMS system, suggesting its great potential in wastewater treatment applications. Overall, this study systematically evaluated the elimination of MTX by the unactivated PMS and solar/PMS treatment processes in water. The obtained findings may have implications for the mechanistic understanding and development of PMS-based processes for the degradation of such micropollutants in wastewater.
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Affiliation(s)
- Shengqi Zhang
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Yuwei Xie
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | | | - Yuefei Ji
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xin Yu
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Mingbao Feng
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China.
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3
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Yang C, Zhang S, Li X, Zhang X, Zhao Q, Li Y, Li H. Impacts of properties of dissolved organic matters on indirect photodegradation of genistein. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 867:161448. [PMID: 36623661 DOI: 10.1016/j.scitotenv.2023.161448] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/03/2023] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Excited triplet states of dissolved organic matters (3DOM*) are one of the most important photochemically-produced reactive intermediates leading to transformation of organic contaminants. However, relationships of photodegradation kinetics of different dissociation states of phenolic organic contaminants with chemical components or properties of 3DOM* are largely unknown. In this study, roles of 3DOM* in photodegradation of polyhydroxy phenolic genistein (Gs) at pH 5, 8 and 12 were investigated taking five kinds of DOM from different sources as examples. Relationships between photodegradation kinetics constants and DOM properties were built. Results showed that the contributions of direct 3DOM*-induced reactions to the total indirect photodegradation of Gs and second-order reaction rate constants (kDOM,Gs) of Gs with 3DOM* increased with pH increases. This was mainly attributed to decreases in vertical ionization energy of Gs at higher pH, endowing Gs with stronger electron donating capacities. kDOM,Gs was found to positively correlate with the specific ultraviolet absorbance at 254 nm, reflecting aromaticity of DOM, and negatively correlate with the absorbance ratio at 254 and 365 nm and contents of dissociated acidic functional groups of DOM, representing molecular weights of DOM, antioxidants and the repulsive forces between 3DOM* and Gs. This study provided a new insight into relationship between DOM properties and indirect photodegradation kinetics of phenolic contaminants in aquatic environments.
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Affiliation(s)
- Chen Yang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China; School of Resources and Civil Engineering, Northeastern University, Shenyang 110004, China
| | - Siyu Zhang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; Beijing Key Laboratory for Emerging Organic Contaminants Control, Tsinghua University, Beijing 100084, China.
| | - Xuehua Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xuejiao Zhang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Qing Zhao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yinghua Li
- School of Resources and Civil Engineering, Northeastern University, Shenyang 110004, China
| | - Haibo Li
- School of Resources and Civil Engineering, Northeastern University, Shenyang 110004, China
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4
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Schroer HW, Londono E, Li X, Lehmler HJ, Arnold W, Just CL. Photolysis of 3-Nitro-1,2,4-triazol-5-one: Mechanisms and Products. ACS ES&T WATER 2023; 3:783-792. [PMID: 36936519 PMCID: PMC10012174 DOI: 10.1021/acsestwater.2c00567] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Insensitive munitions formulations that include 3-nitro-1,2,4-triazol-5-one (NTO) are replacing traditional explosive compounds. While these new formulations have superior safety characteristics, the compounds have greater environmental mobility, raising concern over potential contamination and cleanup of training and manufacturing facilities. Here, we examine the mechanisms and products of NTO photolysis in simulated sunlight to further inform NTO degradation in sunlit surface waters. We demonstrate that NTO produces singlet oxygen and that dissolved oxygen increases the NTO photolysis rate in deionized water. The rate of NTO photolysis is independent of concentration and decreases slightly in the presence of Suwannee River Natural Organic Matter. The apparent quantum yield of NTO generally decreases as pH increases, ranging from 2.0 × 10-5 at pH 12 to 1.3 × 10-3 at pH 2. Bimolecular reaction rate constants for NTO with singlet oxygen and hydroxyl radical were measured to be (1.95 ± 0.15) × 106 and (3.28 ± 0.23) × 1010 M-1 s-1, respectively. Major photolysis reaction products were ammonium, nitrite, and nitrate, with nitrite produced in nearly stoichiometric yield upon the reaction of NTO with singlet oxygen. Environmental half-lives are predicted to span from 1.1 to 5.7 days. Taken together, these data enhance our understanding of NTO photolysis under environmentally relevant conditions.
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Affiliation(s)
- Hunter W. Schroer
- Civil
& Environmental Engineering, The University
of Iowa, Iowa City, Iowa52242, United States
| | - Esteban Londono
- Civil
& Environmental Engineering, The University
of Iowa, Iowa City, Iowa52242, United States
| | - Xueshu Li
- Occupational
& Environmental Health, The University
of Iowa, Iowa City, Iowa52246, United States
| | - Hans-Joachim Lehmler
- Occupational
& Environmental Health, The University
of Iowa, Iowa City, Iowa52246, United States
| | - William Arnold
- Department
of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Dr. SE, Minneapolis, Minnesota55455, United States
| | - Craig L. Just
- Civil
& Environmental Engineering, The University
of Iowa, Iowa City, Iowa52242, United States
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5
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Song N, Wu D, Xu H, Jiang H. Integrated evaluation of the reactive oxygen species (ROS) production characteristics in one large lake under alternating flood and drought conditions. WATER RESEARCH 2022; 225:119136. [PMID: 36155006 DOI: 10.1016/j.watres.2022.119136] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/16/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
Reactive oxygen species (ROS) are omnipresent in natural aquatic environments, and play an important role in biogeochemical cycles. One of the dominant sources of ROS in surface waters was thought to be from dissolved organic matter (DOM) interacting with photochemical process. The properties of DOM were different between the flood and drought periods in lakes; yet, information on how these variations influence ROS photoproduction is unknown. Through a three-year study, the photochemical properties of DOM and the resultant ROS photoproduction between the flood and drought period were determined in the largest freshwater lake in China (Lake Poyang). Results found that quantum yield coefficients of excited triplets (3CDOM*), apparent quantum yields of singlet oxygen (1O2) and hydroxyl radicals (•OH) were holistically higher in the flood period than those in the drought period. The optical properties of DOM showed that DOM in the flood period featured an allochthonous input, accompanied by higher molecular size (E2/E3), aromatic content (SUVA254), humification degree (HIX), while DOM in the drought period was mainly internal input. Fourier transform ion cyclotron resonance mass spectrometry (FI-ICR MS) further revealed that some refractory components, such as lignin-like and carboxyl-rich alicyclic molecules (CRAM) presented higher abundance in the flood period, and played the positive impacts on ROS production. Orthogonal partial least squares (OPLS) were used to build novel multivariate predictive models for indicating the spatio-temporal ROS production. Also, the relatively higher steady-state concentrations of 3CDOM* and 1O2 in the flood period could significantly diminish the half-lives of acetochlor. Considering the photochemical activity of DOM varied considerably at different periods, this study provided a new method to predict ROS production and contributed to a new insight into stage-specific emerging contaminants removing in natural aquatic environments.
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Affiliation(s)
- Na Song
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Dinggui Wu
- Organic Geochemistry Unit, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Huacheng Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
| | - Helong Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
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6
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Wang L, Zheng Y, Zhou Y, Lu J, Chovelon JM, Ji Y. Aquatic photolysis of ketoprofen generates products with photosensitizing activity and toxicity. WATER RESEARCH 2022; 210:117982. [PMID: 34954366 DOI: 10.1016/j.watres.2021.117982] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Ketoprofen (KTF) is a nonsteroidal anti-inflammatory drug frequently detected in natural and engineering waters. Because KTF is particularly photolabile (half-life ∼4 min), knowledge of the fate and ecological risks of KTF photoproducts in the aquatic environment is especially essential. Herein, we systematically investigated the photophysics, photochemistry, and photosensitization of KTF photoproducts in aqueous solution under 365 nm irradiation (UV365). Results show that KTF photolyzed rapidly and formed 3-ethyl-α-hydroxylbenzophenone (EtOH-BP), 3-ethyl-α-hydroperoxylbenzophenone (EtOOH-BP), 3-acetylbenzophenone (AcBP), and 3-ethylbenzophenone (EtBP), as identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-resolution mass spectrometry (HRMS). The presence of O2 significantly affected the evolution of photoproducts during KTF photolysis. The photophysical properties of EtBP and AcBP were characterized by spectroscopic approaches. In particular, transient absorption spectra obtained by nanosecond laser flash photolysis (LFP) indicated that EtBP and AcBP were excited to triplet states with lifetimes of 28 and 2.4 µs, respectively. EtBP underwent further photodegradation, giving rise to EtOH-BP, EtOOH-BP, and AcBP upon UV365 irradiation. The reaction is proposed to proceed through an excimer precursor (3[EtBP···EtBP]*) followed by intramolecular H-abstraction. In contrast, AcBP was relatively photostable, particularly under aerated condition. Both EtBP and AcBP have strong photosensitizing activity, as evidenced by the triplet probe 4-(N,N-dimethylamino)benzonitrile (DMABN). ECOSAR program suggested that the photoproducts are more ecotoxic and bioaccumulative than the parent KTF. Results of this study underscore the need to scrutinize the formation and fate of KTF photoproducts in sunlit surface waters.
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Affiliation(s)
- Lixiao Wang
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yajie Zheng
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiran Zhou
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Junhe Lu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jean-Marc Chovelon
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, F-69626, Villeurbanne, France
| | - Yuefei Ji
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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7
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Le Roux DM, Powers LC, Blough NV. Photoproduction Rates of One-Electron Reductants by Chromophoric Dissolved Organic Matter via Fluorescence Spectroscopy: Comparison with Superoxide and Hydrogen Peroxide Rates. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:12095-12105. [PMID: 34383497 DOI: 10.1021/acs.est.1c04043] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
One-electron reductants (OER) photoproduced by chromophoric dissolved organic matter (CDOM) have been shown to be likely precursors for the formation of superoxide and subsequently hydrogen peroxide. An improved method that employs a nitroxide radical probe (3AP) has been developed and utilized to determine the photoproduction rates of OER from a diverse set of CDOM samples. 3AP reacts with OER to produce the hydroxylamine, which is then derivatized with fluorescamine and quantified spectrofluorometrically. Although less sensitive than traditional methods for measuring RO2•-, measuring RH provides a simpler and faster method of estimating RO2•- and is amenable to continuous measurement via flow injection analysis. Production rates of OER (RH), superoxide (RO2•-), and hydrogen peroxide (RH2O2) have a similar wavelength dependence, indicating a common origin. If all the OER react with molecular oxygen to produce superoxide, then the simplest mechanism predicts that RH/RH2O2 and RO2•-/RH2O2 should be equal to 2. However, our measurements reveal RH/RH2O2 values as high as 16 (5.7-16), consistent with prior results, and RO2•-/RH2O2 values as high as 8 (5.4-8.2). These results indicate that a substantial fraction of superoxide (65-88%) is not undergoing dismutation. A reasonable oxidative sink for superoxide is reaction with photoproduced phenoxy radicals within CDOM.
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Affiliation(s)
- Danielle M Le Roux
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Leanne C Powers
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, Solomons, Maryland 20688, United States
| | - Neil V Blough
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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8
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Palma D, Sleiman M, Voldoire O, Beauger A, Parlanti E, Richard C. Study of the dissolved organic matter (DOM) of the Auzon cut-off meander (Allier River, France) by spectral and photoreactivity approaches. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:26385-26394. [PMID: 32363461 PMCID: PMC7332482 DOI: 10.1007/s11356-020-09005-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/22/2020] [Indexed: 05/05/2023]
Abstract
Wetlands are recognized for the importance of their hydrological function and biodiversity, and there is now a consensus to protect and restore them as well as to complete the knowledge on their functioning. Here, we studied the dissolved organic matter (DOM) of a wetland composed of the Auzon cut-off meander, the Allier River, the alluvial fluvial flow, and watershed aquifer. Water was sampled at different locations, in spring, summer, and autumn. For each sample, DOM was characterized for its chemical and optical properties and its photooxidant capacity through its ability to generate DOM triplet excited states (3DOM*) and singlet oxygen upon simulated solar light exposure. UV-visible and fluorescence indices revealed that DOM was mainly microbial-derived whatever the sampling sites with spatial and temporal variations in terms of aromaticity (5.5-22%), specific UV absorbance at 254 nm (0.28-2.82 L m-1mgC-1), ratio of the absorbance at 254 and 365 nm (4.6-10.8), fluorescence index (1.35-166), and biological index (0.812-2.25). All the samples generated 3DOM* and singlet oxygen, rates of formation of which showed parallel variations. Using principal component analysis (PCA), we found positive correlations between the sensitizing properties of DOM samples and parameters associated to the abundance of low molecular weight and low absorbing chromophores. Moreover, the parameter variation across the wetland reinforced the hydrological movements observed in a previous study, suggesting that these parameters could be used as water connection tracers.
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Affiliation(s)
- Davide Palma
- Université Clermo Auvergne, CNRS, SIGMA-Clermont ICCF, 63000, Clermont-Ferrand, France
| | - Mohamad Sleiman
- Université Clermo Auvergne, CNRS, SIGMA-Clermont ICCF, 63000, Clermont-Ferrand, France
| | - Olivier Voldoire
- Université Clermont Auvergne, CNRS, GEOLAB, 63000, Clermont-Ferrand, France
| | - Aude Beauger
- Université Clermont Auvergne, CNRS, GEOLAB, 63000, Clermont-Ferrand, France
| | - Edith Parlanti
- Université Bordeaux, CNRS, UMR EPOC, 33405, Talence, France
| | - Claire Richard
- Université Clermo Auvergne, CNRS, SIGMA-Clermont ICCF, 63000, Clermont-Ferrand, France.
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9
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Wang J, Wang K, Guo Y, Niu J. Photochemical degradation of nebivolol in different natural organic matter solutions under simulated sunlight irradiation: Kinetics, mechanism and degradation pathway. WATER RESEARCH 2020; 173:115524. [PMID: 32006808 DOI: 10.1016/j.watres.2020.115524] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/17/2020] [Accepted: 01/18/2020] [Indexed: 06/10/2023]
Abstract
Nebivolol (NEB) is widely used for the treatment of hypertension and chronic heart failure and has become an ubiquitous emerging organic pollutant. It has been shown to undergo direct photolysis, but the role of DOM in its degradation kinetics and mechanism is not well understood. In this study, we studied the photochemical behavior of NEB in the presence of seawater DOM (SW-DOM) and freshwater DOM (SRNOM) under simulated sunlight irradiation. SW-DOM had a promotion effect on NEB photodegradation, whereas SRNOM retarded its photolytic transformation. After eliminating the influence of light screening, we found that the indirect photodegradation rate of NEB in the presence of SRNOM was lower than that in the presence of SW-DOM. Results show that the indirect photodegradation pathway occurred by reaction with triplet-excited DOM (3DOM*). The second-order rate constants for 3SW-DOM* and 3SRNOM* reaction with NEB are 3.7 × 109 M-1 s-1 and 3.7 × 108 M-1 s-1, respectively. The electron donating capacity of SRNOM is higher than that of SW-DOM, indicating that SRNOM may contain more activated phenolic moieties. SRNOM may thus have higher antioxidant activity, leading a higher inhibitory effect on NEB photodegradation. A total of six degradation products were identified in the absence and presence of DOM by HPLC-ESI-MS/MS. The substitution of F by OH-groups and further oxidation a OH-group in the lateral chain to a ketone, and cleavage of N-C bond by the attack of 3DOM* are here proposed as the main degradation pathways.
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Affiliation(s)
- Jieqiong Wang
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR China
| | - Kai Wang
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR China
| | - Yuchen Guo
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR China
| | - Junfeng Niu
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, 523808, PR China.
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10
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Wang J, Chen J, Qiao X, Zhang YN, Uddin M, Guo Z. Disparate effects of DOM extracted from coastal seawaters and freshwaters on photodegradation of 2,4-Dihydroxybenzophenone. WATER RESEARCH 2019; 151:280-287. [PMID: 30616040 DOI: 10.1016/j.watres.2018.12.045] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/04/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
Dissolved organic matter (DOM) plays an important role in degradation of organic pollutants by photochemically-produced reactive intermediates (RIs), such as excited triplet-states of DOM (3DOM*), singlet oxygen (1O2) and hydroxyl radical (·OH). However, it is not clear whether DOM extracted from coastal seawaters (CS-DOM) and DOM derived from freshwaters (FW-DOM) exhibit similar effects on photodegradation of organic micropollutants. Herein, 2,4-dihydroxybenzophenone (BP-1) was adopted as a model compound to probe the effects of different DOM on photodegradation kinetics of organic micropollutants. Results show that the CS-DOM promotes the photodegradation of BP-1 mainly via the pathway involving 3DOM*; while 3DOM*, 1O2 and ·OH are responsible for BP-1 photodegradation in the presence of the FW-DOM. Compared with the FW-DOM, the CS-DOM undergoes more photobleaching, and contains less aromatic C=C and C=O functional groups. Although 3DOM* formation quantum yields for the CS-DOM are relatively higher than those for the FW-DOM, the CS-DOM has lower rates of light absorption, leading to lower steady-state RI concentrations for the CS-DOM. BP-1 photodegradation in the presence of the CS-DOM is faster than in the presence of the FW-DOM, due to higher second-order reaction rate constants between BP-1 and CS-3DOM* and fewer antioxidants contained in the CS-DOM.
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Affiliation(s)
- Jieqiong Wang
- 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.
| | - Xianliang Qiao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Ya-Nan Zhang
- School of Environment, Northeast Normal University, Changchun, Jilin, 130024, China
| | - Misbah Uddin
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Zhongyu Guo
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
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11
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Picardo M, Filatova D, Nuñez O, Farré M. Recent advances in the detection of natural toxins in freshwater environments. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2018.12.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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12
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Huang X, Zhao J, Xu Q, Li X, Wang D, Yang Q, Liu Y, Tao Z. Enhanced volatile fatty acids production from waste activated sludge anaerobic fermentation by adding tofu residue. BIORESOURCE TECHNOLOGY 2019; 274:430-438. [PMID: 30553083 DOI: 10.1016/j.biortech.2018.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/04/2018] [Accepted: 12/06/2018] [Indexed: 06/09/2023]
Abstract
In this study, an economical and eco-friendly strategy (i.e., adding tofu residue (TR) into waste activated sludge (WAS)) to enhance volatile fatty acid (VFA) production was reported. Experimental results indicated that the maximal VFA yield at T/W ratio (TR/WAS, the ratio of the volatile suspended solids (VSS)) of 0.64 on 5 d was 240.8 mg COD/g VSS, which was 10.2 and 1.1-fold of that in sole WAS and sole TR, respectively. The feasible fermentation time was shortened by 2 days, as compared with sole WAS or sole TR. Mechanism investigation showed that the addition of TR promoted solubilization, hydrolysis, and acidogenesis processes. The synergistic effect of microorganisms contained in TR and WAS may be responsible for the enhancement of lignocellulose hydrolysis and VFA generation. Appropriate amounts of mineral elements in TR benefited solubilization, the soluble iron and calcium in TR could contribute to the phosphorus removal in fermentation liquor.
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Affiliation(s)
- Xiaoding Huang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Jianwei Zhao
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China; School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Qiuxiang Xu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Xiaoming Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Qi Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Yang Liu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Ziletao Tao
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
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13
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Liu W, Jin L, Chen K, Li Y, Dahlgren RA, Ma M, Wang X. Inhibitory effects of natural organic matter on methyltriclosan photolysis kinetics. RSC Adv 2018; 8:21265-21271. [PMID: 35539952 PMCID: PMC9080868 DOI: 10.1039/c8ra03512a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/05/2018] [Indexed: 12/12/2022] Open
Abstract
This study evaluated the effects and related mechanisms of natural organic matter (NOM) on the photolysis of methyltriclosan (MTCS), a metabolite of triclosan. Addition of two representative NOM isolates, Pony Lake fulvic acid (PLFA-microbial origin) and Suwannee River fulvic acid (SRFA-terrestrial origin), significantly inhibited the direct photolytic rate of MTCS by ∼70%. The MTCS photolytic rate in the presence of PLFA was greater than for SRFA. NOM not only suppressed photolysis by light-shielding, but also produced ROS to oxidatively degrade MTCS and/or triplet NOM (3NOM*) to sensitize degradation. The dual effects of light-screening and photo-sensitization led to an overall decrease in photolysis of MTCS with a positive concentration-dependence. Upon addition of NOM, EPR documented the occurrence of 1O2 and ˙OH in the photolytic process, and the bimolecular k value for the reaction of 1O2 with MTCS was 1.86 × 106 M−1 s−1. ROS-quenching experiments indicated that the contribution of ˙OH (19.1–29.5%) to indirect photolysis of MTCS was lower than for 1O2 (38.3–58.7%). Experiments with D2O further demonstrated that 1O2 participated in MTCS photodegradation. Moreover, the addition of sorbic acid and O2 gas to the reaction confirmed the participation of 3NOM* as a key reactant in the photochemical transformation of MTCS. This is the first comprehensive analysis of NOM effects on the indirect photolysis of MTCS, which provides new insights for understanding the environmental fate of MTCS in natural environments. We demonstrate that PLFA and SRFA inhibit the MTCS photolysis by synergistic effects of light-shielding and photo-sensitization.![]()
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Affiliation(s)
- Wei Liu
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
| | - Lide Jin
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
| | - Kai Chen
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
| | - Yanyan Li
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
| | - Randy A. Dahlgren
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
| | - Meiping Ma
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
| | - Xuedong Wang
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province
- Southern Zhejiang Water Research Institute
- Wenzhou Medical University
- Wenzhou 325035
- People's Republic of China
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14
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Arnold WA, Oueis Y, O'Connor M, Rinaman JE, Taggart MG, McCarthy RE, Foster KA, Latch DE. QSARs for phenols and phenolates: oxidation potential as a predictor of reaction rate constants with photochemically produced oxidants. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:324-338. [PMID: 27942650 DOI: 10.1039/c6em00580b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Quantitative structure-activity relationships (QSARs) for prediction of the reaction rate constants of phenols and phenolates with three photochemically produced oxidants, singlet oxygen, carbonate radical, and triplet excited state sensitizers/organic matter, are developed. The predictive variable is the one-electron oxidation potential (E1), which is calculated for each species using density functional theory. The reaction rate constants are obtained from the literature, and for singlet oxygen, are augmented with new experimental data. Calculated E1 values have a mean unsigned error compared to literature values of 0.04-0.06 V. For singlet oxygen, a single linear QSAR that includes both phenols and phenolates is developed that predicts experimental rate constants, on average, to within a factor of three. Predictions for only 6 out of 87 compounds are off by more than a factor of 10. A more limited data set for carbonate radical reactions with phenols and phenolates also gives a single linear QSAR with prediction of rate constant being accurate to within a factor of three. The data for the reactions of phenols with triplet state sensitizers demonstrate that two sensitizers, 2-acetonaphthone and methylene blue, most closely predict the reactivity trend of triplet excited state organic matter with phenols. Using sensitizers with stronger reduction potentials could lead to overestimation of rate constants and thus underestimation of phenolic pollutant persistence.
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Affiliation(s)
- William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
| | - Yan Oueis
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
| | - Meghan O'Connor
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
| | - Johanna E Rinaman
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Miranda G Taggart
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Rachel E McCarthy
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Kimberley A Foster
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Douglas E Latch
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
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15
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Rosario-Ortiz FL, Canonica S. Probe Compounds to Assess the Photochemical Activity of Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12532-12547. [PMID: 27736067 DOI: 10.1021/acs.est.6b02776] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The photochemical properties of dissolved organic matter (DOM) have been of interest to scientists and engineers since the 1970s. Upon light absorption, chromophoric DOM (CDOM) can sensitize the formation of different short-lived reactive intermediates (RIs), including hydroxyl radical (•OH), singlet oxygen (1O2) and superoxide radical anion (O2•-). In addition, a fraction of the excited singlet states in CDOM decays into excited triplet states (3CDOM*), which are also important photochemical transients in environmental systems. These RIs have a significant impact on different processes in sunlit waters, including degradation of organic contaminants and the inactivation of pathogens. Due to their transient nature and low steady-state concentrations, the use of common analytical techniques for the direct measurement of these species is impractical. Therefore, specific probe compounds (PCs) are used. PCs include furfuryl alcohol for 1O2, and terephthalic acid for •OH. In this publication, we present a critical review of the use of PCs for the assessment of the formation of photochemically generated RIs. We first introduce the concept of a PC, including the kinetic treatment and necessary assumptions needed to conduct a specific measurement. Afterward, we present short overviews of the most studied RIs and review relevant issues regarding the use of specific PCs for their measurement. We finalize by offering recommendations regarding the use of PCs in environmental photochemistry.
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Affiliation(s)
- Fernando L Rosario-Ortiz
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133 CH-8600, Dübendorf, Switzerland
- Department of Civil, Environmental and Architectural Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133 CH-8600, Dübendorf, Switzerland
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16
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McNeill K, Canonica S. Triplet state dissolved organic matter in aquatic photochemistry: reaction mechanisms, substrate scope, and photophysical properties. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:1381-1399. [PMID: 27722628 DOI: 10.1039/c6em00408c] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Excited triplet states of chromophoric dissolved organic matter (3CDOM*) play a major role among the reactive intermediates produced upon absorption of sunlight by surface waters. After more than two decades of research on the aquatic photochemistry of 3CDOM*, the need for improving the knowledge about the photophysical and photochemical properties of these elusive reactive species remains considerable. This critical review examines the efforts to date to characterize 3CDOM*. Information on 3CDOM* relies mainly on the use of probe compounds because of the difficulties associated with directly observing 3CDOM* using transient spectroscopic methods. Singlet molecular oxygen (1O2), which is a product of the reaction between 3CDOM* and dissolved oxygen, is probably the simplest indicator that can be used to estimate steady-state concentrations of 3CDOM*. There are two major modes of reaction of 3CDOM* with substrates, namely triplet energy transfer or oxidation (via electron transfer, proton-coupled electron transfer or related mechanisms). Organic molecules, including several environmental contaminants, that are susceptible to degradation by these two different reaction modes are reviewed. It is proposed that through the use of appropriate sets of probe compounds and model photosensitizers an improved estimation of the distribution of triplet energies and one-electron reduction potentials of 3CDOM* can be achieved.
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Affiliation(s)
- Kristopher McNeill
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland.
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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17
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Leresche F, von Gunten U, Canonica S. Probing the Photosensitizing and Inhibitory Effects of Dissolved Organic Matter by Using N,N-dimethyl-4-cyanoaniline (DMABN). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10997-11007. [PMID: 27617886 DOI: 10.1021/acs.est.6b02868] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dissolved organic matter (DOM) can act as a photosensitizer and an inhibitor in the phototransformation of several nitrogen-containing organic contaminants in surface waters. The present study was performed to select a probe molecule that is suitable to measure these antagonistic properties of DOM. Out of nine studied nitrogen-containing aromatic compounds, 4-cyanoaniline, N,N-dimethyl-4-cyanoaniline (DMABN), sotalol (a β-blocker) and sulfadiazine (a sulfonamide antibiotic) exhibited a marked photosensitized transformation that could be substantially inhibited by addition of phenol as a model antioxidant. The photosensitized transformation of DMABN, the selected probe compound, was characterized in detail under UV-A and visible irradiation (λ > 320 nm) to avoid direct phototransformation. Low reactivity of DMABN with singlet oxygen was found (second-order rate constant <2 × 107 M-1 s-1). Typically at least 85% of the reactivity of DMABN could be inhibited by DOM or the model antioxidant phenol. The photosensitized transformation of DMABN mainly proceeded (>72%) through demethylation yielding N-methyl-4-cyanoaniline and formaldehyde as primary products. In solutions of standard DOM extracts and their mixtures the phototransformation rate constant of DMABN was shown to vary nonlinearly with the DOM concentration. Model equations describing the dependence of such rate constants on DOM and model antioxidant concentrations were successfully used to fit experimental data.
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Affiliation(s)
- Frank Leresche
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich , Universitätstrasse 16, CH-8092, Zürich, Switzerland
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
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18
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Wang H, Wang M, Wang H, Gao J, Dahlgren RA, Yu Q, Wang X. Aqueous photochemical degradation of BDE-153 in solutions with natural dissolved organic matter. CHEMOSPHERE 2016; 155:367-374. [PMID: 27135698 DOI: 10.1016/j.chemosphere.2016.04.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/02/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
The compound 2,2',4,4',5,5'-hexabrominated diphenyl ether (BDE-153) is an intermediate photolytic product in the degradation of highly brominated diphenyl ethers to lower brominated forms. Herein, we report the effects of two natural organic matter (NOM) sources, Suwannee River fulvic acid (SRFA) and Pony Lake fulvic acid (PLFA), on BDE-153 photolysis in water. The rate constant (k) and half-life of BDE-153 was 2.26 × 10(-2) min(-1) and 30.72 min under UV-Vis irradiation (direct photolysis at λ > 290 nm). The k value for BDE-153 decreased markedly in the presence of NOM with a larger decrease in the presence of PLFA than SRFA. Electron spin resonance (ESR) demonstrated generation of free radicals in the photolytic process that mainly involved (1)O2 and OH. The biomolecular k values for reaction of (1)O2 and OH with BDE-153 were 3.65 × 10(6) and 7.70 × 10(8) M(-1) s(-1), respectively. The contribution of OH (28.7-31.0%) to the indirect photolysis of BDE-153 was higher than for (1)O2 (12.9-14.9%). The photolytic rate of BDE-153 in oxygen-rich (aerated) solution was much slower than in oxygen-poor (nitrogen-sparged) conditions, demonstrating that (3)NOM* is a more effective reagent for degradation of BDE-153 than (1)O2. Addition of sorbic acid (a (3)NOM* quencher) significantly reduced the photolytic rate of BDE-153 confirming the important role of (3)NOM* in indirect photolysis. In the presence of NOM, BDE-153 indirect photolysis was facilitated mainly by reaction with (3)NOM* and OH. To the best of our knowledge, this is the first comprehensive investigation of indirect photolysis of BDE-153 in water containing NOM.
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Affiliation(s)
- Huili Wang
- College of Life Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Mei Wang
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province, Wenzhou Medical University, Wenzhou 325035, China
| | - Hui Wang
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province, Wenzhou Medical University, Wenzhou 325035, China
| | - Jiajia Gao
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province, Wenzhou Medical University, Wenzhou 325035, China
| | - Randy A Dahlgren
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province, Wenzhou Medical University, Wenzhou 325035, China
| | - Qing Yu
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province, Wenzhou Medical University, Wenzhou 325035, China
| | - Xuedong Wang
- Key Laboratory of Watershed Sciences and Health of Zhejiang Province, Wenzhou Medical University, Wenzhou 325035, China.
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19
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An J, Li G, An T, Nie X. Indirect photochemical transformations of acyclovir and penciclovir in aquatic environments increase ecological risk. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:584-592. [PMID: 26356329 DOI: 10.1002/etc.3238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/01/2015] [Accepted: 09/08/2015] [Indexed: 06/05/2023]
Abstract
Acyclovir and penciclovir, 2 antiviral drugs, are increasingly detected in aquatic environments. The present study explores the natural photochemical transformation mechanisms and fate of these drugs, examining direct and indirect photochemical transformation under simulated sunlight irradiation. The 2 antiviral drugs are photostable under certain conditions but significantly degrade in the presence of chromophoric dissolved organic matter (DOM). The degradation rate associated with the drugs' indirect photochemical transformation scaled with chromophoric DOM concentration. Quenchers and sensitizers were used to identify indirect photochemical transformation mechanism. Results suggested that both pharmaceuticals could be transformed by reacting with (1)O2, (•)OH, and excited chromophoric DOM. The (1)O2 played an important role in indirect photochemical transformation. Furthermore, the reaction kinetics between their substructural molecules, guanine, isocytosine, and imidazole, with different reactive oxygen species were evaluated to determine which substrate functionalities were most susceptible to singlet oxygenation. Imidazole was identified as the reaction site for (1)O2, and preliminary (1)O2 oxidation mechanisms were further evaluated based on liquid chromatographic-tandem mass spectrometric results. Finally, aquatic ecotoxicity assessment of phototransformed solutions revealed that the degradation of acyclovir and penciclovir may not ultimately diminish environmental risk because of either formation of more toxic intermediates than parent pharmaceuticals or some synergistic effects existing between the intermediates.
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Affiliation(s)
- Jibin An
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Guiying Li
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Taicheng An
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, People's Republic of China
| | - Xiangping Nie
- Institute of Hydrobiology, Jinan University, Guangzhou, People's Republic of China
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20
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Li Y, Chen J, Qiao X, Zhang H, Zhang YN, Zhou C. Insights into photolytic mechanism of sulfapyridine induced by triplet-excited dissolved organic matter. CHEMOSPHERE 2016; 147:305-310. [PMID: 26766369 DOI: 10.1016/j.chemosphere.2015.12.115] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/23/2015] [Accepted: 12/27/2015] [Indexed: 06/05/2023]
Abstract
The ubiquity of sulfonamide antibiotics (SAs) in natural waters urges insights into their fate for ecological risk assessment in the aqueous euphotic zone. In this study, we investigated the effect of dissolved organic matter (DOM) on the photolysis of SAs with sulfapyridine as a reprentative. Results show that excited triplet state DOM ((3)DOM(∗)) is largely responsible for the photodegradation of sulfapyridine. The reaction of (3)DOM(∗) with a substructure model compound of SAs confirmed that sulfapyridine has one reaction site (aniline-N). Density functional theory (DFT) calculation was performed, which indicates that the anionic sulfapyridine has higher (3)DOM(∗) reactivity than that of the neutral form, which was also confirmed by steady state photolytic experiments. In the reaction, electrons of the aniline-N transfer to the carbonyl oxygen atom of (3)DOM(∗) moiety, followed by proton transfer, and leading to the formation of sulfapyridine radicals. The photolytic mechansim of sulfapyridine initiated by (3)DOM(∗) is helpful in understanding the photochemical fate and assessing the ecological risks of SAs in the aquatic environment.
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Affiliation(s)
- Yingjie Li
- 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.
| | - Xianliang Qiao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Heming Zhang
- College of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Ya-nan Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Chengzhi Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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21
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Latch DE. The Role of Singlet Oxygen in Surface Water Photochemistry. SURFACE WATER PHOTOCHEMISTRY 2015. [DOI: 10.1039/9781782622154-00139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Singlet oxygen, (1O2, 1Δg), is a selective oxidant produced in sunlit surface waters. It is an electrophile produced from the quenching of excited state triplet natural organic matter (3NOM) by dissolved oxygen and it reacts with electron-rich alkenes, sulfides, and phenols. The concentration of 1O2 is high near the NOM molecules that sensitize its production and significantly decreases moving away from the NOM source. This chapter discusses the formation, quenching, reactivity, and detection of 1O2 and includes examples of surface water contaminants that react with 1O2.
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Affiliation(s)
- Douglas E. Latch
- Department of Chemistry, Seattle University 901 12th Avenue Seattle WA 98122 USA
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22
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Kelly MM, Rearick DC, Overgaard CG, Schoenfuss HL, Arnold WA. Sorption of isoflavones to river sediment and model sorbents and outcomes for larval fish exposed to contaminated sediment. JOURNAL OF HAZARDOUS MATERIALS 2015; 282:26-33. [PMID: 24792866 DOI: 10.1016/j.jhazmat.2014.03.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 02/26/2014] [Accepted: 03/26/2014] [Indexed: 06/03/2023]
Abstract
Isoflavones are compounds whose presence in the aquatic environment is increasingly recognized and may be of concern due to their potential to act as endocrine disruptors. Sorption to particles may be a relevant removal mechanism for isoflavones. This work investigated the influence of pH, ionic strength, and sediment composition on sorption of genistein and daidzein, two key isoflavones, using sorption isotherms and edges. The effect of sorbed isoflavones on the survival, growth, and predator avoidance performance of larval fathead minnows (Pimephales promelas) was assessed. Sorption to goethite and kaolinite was pH-dependent, with a maximum near pH 7 for both compounds. Sorption to montmorillonite was ionic-strength dependent but largely pH-independent. Overall, sorption to sediments is likely to sequester less than 5% of isoflavones in a discharge. No statistically significant effects were observed for larvae exposed to sorbed isoflavones, suggesting that sorption to sediments reduces exposure to isoflavones.
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Affiliation(s)
- Megan M Kelly
- Water Resources Science Graduate Program, University of Minnesota, 1985 Buford Ave., Saint Paul, MN 55108, United States
| | - Daniel C Rearick
- Aquatic Toxicology Laboratory, Saint Cloud State University, 720 4th Ave. South, Saint Cloud, MN 56301, United States
| | - Camilla G Overgaard
- Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway
| | - Heiko L Schoenfuss
- Aquatic Toxicology Laboratory, Saint Cloud State University, 720 4th Ave. South, Saint Cloud, MN 56301, United States
| | - William A Arnold
- Water Resources Science Graduate Program, University of Minnesota, 1985 Buford Ave., Saint Paul, MN 55108, United States; Department of Civil Engineering, University of Minnesota, 500 Pillsbury Dr. SE, Minneapolis, MN 55455, United States.
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23
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Huvaere K, Skibsted LH. Flavonoids protecting food and beverages against light. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2015; 95:20-35. [PMID: 24961228 DOI: 10.1002/jsfa.6796] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 06/16/2014] [Indexed: 06/03/2023]
Abstract
Flavonoids, which are ubiquitously present in the plant kingdom, preserve food and beverages at the parts per million level with minor perturbation of sensory impressions. Additionally, they are safe and possibly contribute positive health effects. Flavonoids should be further exploited for the protection of food and beverages against light-induced quality deterioration through: (1) direct absorption of photons as inner filters protecting sensitive food components; (2) deactivation of (triplet-)excited states of sensitisers like chlorophyll and riboflavin; (3) quenching of singlet oxygen from type II photosensitisation; and (iv) scavenging of radicals formed as reaction intermediates in type I photosensitisation. For absorption of light, combinations of flavonoids, as found in natural co-pigmentation, facilitate dissipation of photon energy to heat thus averting photodegradation. For protection against singlet oxygen and triplet sensitisers, chemical quenching gradually decreases efficiency hence the pathway to physical quenching should be optimised through product formulation. The feasibility of these protection strategies is further supported by kinetic data that are becoming available, allowing for calculation of threshold levels of flavonoids to prevent beer and dairy products from going off. On the other hand, increasing understanding of the interplay between light and matrix physicochemistry, for example the effect of aprotic microenvironments on phototautomerisation of compounds like quercetin, opens up for engineering better light-to-heat converting channels in processed food to eventually prevent quality loss.
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Affiliation(s)
- Kevin Huvaere
- Department of Food Science, Faculty of Sciences, University of Copenhagen, Rolighedsvej 30, DK-1958, Denmark
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Fabbri D, Minella M, Maurino V, Minero C, Vione D. Photochemical transformation of phenylurea herbicides in surface waters: a model assessment of persistence, and implications for the possible generation of hazardous intermediates. CHEMOSPHERE 2015; 119:601-607. [PMID: 25128892 DOI: 10.1016/j.chemosphere.2014.07.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/08/2014] [Accepted: 07/13/2014] [Indexed: 06/03/2023]
Abstract
This work models the phototransformation kinetics in surface waters of five phenylurea herbicides (diuron, fenuron, isoproturon, metoxuron and chlortoluron), for which important photochemical parameters are available in the literature (direct photolysis quantum yields and reaction rate constants with ·OH, CO3(-·) and the triplet states of chromophoric dissolved organic matter, (3)CDOM*). Model calculations suggest that isoproturon and metoxuron would be the least photochemically persistent and diuron the most persistent compound. Reactions with ·OH and (3)CDOM* would be the main phototransformation pathways for all compounds in the majority of environmental conditions. Reaction with CO3(-) could be important in waters with low dissolved organic carbon (DOC), while direct photolysis would be negligible for fenuron, quite important for chlortoluron, and somewhat significant for the other compounds. The direct photolysis of metoxuron and diuron is known to increase toxicity, and such a photoreaction pathway would be enhanced at intermediate DOC values (1-4 mg C L(1)). The reaction between phenylureas and ·OH is known to produce toxic intermediates, differently from (3)CDOM*. Therefore, the shift of reactivity from ·OH to (3)CDOM* with increasing DOC could reduce the environmental impact of photochemical transformation.
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Affiliation(s)
- Debora Fabbri
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Marco Minella
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Valter Maurino
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Claudio Minero
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Davide Vione
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1); Università degli Studi di Torino, Centro Interdipartimentale NatRisk, Via Leonardo da Vinci 44, 10095 Grugliasco, TO, Italy(2).
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Gan Z, Sun H, Wang R, Hu H, Zhang P, Ren X. Transformation of acesulfame in water under natural sunlight: joint effect of photolysis and biodegradation. WATER RESEARCH 2014; 64:113-122. [PMID: 25046375 DOI: 10.1016/j.watres.2014.07.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/30/2014] [Accepted: 07/01/2014] [Indexed: 06/03/2023]
Abstract
The transformation of acesulfame in water under environmentally relevant conditions, including direct and indirect photolysis, biodegradation, and hydrolysis, was systematically evaluated. Under natural sunlight, both direct and indirect photolysis of acesulfame were negligible in sterilized systems at neutral or alkaline pH, whereas direct photolysis occurred at pH of 4 with a rate constant of 0.0355 d(-1) in deionized water. No significant reduction in acesulfame contents was found in the dark controls or in the incubation experiments, indicating acesulfame was resistant to hydrolysis and biodegradation. In unsterilized systems, photolysis was substantially enhanced, implying that there was a joint effect of photolysis and biodegradation or that the sterilization process had the secondary effect of inactivating some photosensitizers. The near-surface summer half-life of acesulfame in the water from the Haihe River was 9 d. Specific experiments revealed the involvement of (1)O2/(3)DOM* in acesulfame photolysis, whereas OH exhibited only a slight contribution in the presence of DOM or bicarbonate. As indicated by the total organic carbon data, no significant mineralization occurred in both sterilized and unsterilized systems after acesulfame was irradiated under simulated sunlight for 7 d, suggesting the generation of persistent intermediates. Finally, major degradation intermediates were analyzed, and the degradation pathways of acesulfame under environmentally relevant conditions were proposed for the first time.
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Affiliation(s)
- Zhiwei Gan
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Hongwen Sun
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
| | - Ruonan Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Hongwei Hu
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Pengfei Zhang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xinhao Ren
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
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Zhao Q, Cheng X, Wu J, Yu X. Sulfur-free exfoliated graphite with large exfoliated volume: Preparation, characterization and its adsorption performance. J IND ENG CHEM 2014. [DOI: 10.1016/j.jiec.2014.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Vione D, Minella M, Maurino V, Minero C. Indirect photochemistry in sunlit surface waters: photoinduced production of reactive transient species. Chemistry 2014; 20:10590-606. [PMID: 24888627 DOI: 10.1002/chem.201400413] [Citation(s) in RCA: 261] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 11/09/2022]
Abstract
This paper gives an overview of the main reactive transient species that are produced in surface waters by sunlight illumination of photoactive molecules (photosensitizers), such as nitrate, nitrite, and chromophoric dissolved organic matter (CDOM). The main transients (˙OH, CO3(-˙) , (1)O2, and CDOM triplet states) are involved in the indirect phototransformation of a very wide range of persistent organic pollutants in surface waters.
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Affiliation(s)
- Davide Vione
- Department of Chemistry, University of Torino, Via Pietro Giuria 5, 10125 Torino (Italy), Fax: (+39) 011-6705242; NatRisk Inter-Department Centre, University of Torino, Via Leonardo Da Vinci 44, 10095 Grugliasco (TO) (Italy).
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Wenk J, Eustis SN, McNeill K, Canonica S. Quenching of excited triplet states by dissolved natural organic matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:12802-10. [PMID: 24083647 DOI: 10.1021/es402668h] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Excited triplet states of aromatic ketones and quinones are used as proxies to assess the reactivity of excited triplet states of the dissolved organic matter ((3)DOM*) in natural waters. (3)DOM* are crucial transients in environmental photochemistry responsible for contaminant transformation, production of reactive oxygen species, and potentially photobleaching of DOM. In recent photochemical studies aimed at clarifying the role of DOM as an inhibitor of triplet-induced oxidations of organic contaminants, aromatic ketones have been used in the presence of DOM, and the question of a possible interaction between their excited triplet states and DOM has emerged. To clarify this issue, time-resolved laser spectroscopy was applied to measure the excited triplet state quenching of four different model triplet photosensitizers induced by a suite of DOM from various aquatic and terrestrial sources. While no quenching for the anionic triplet sensitizers 4-carboxybenzophenone (CBBP) and 9,10-anthraquinone-2,6-disulfonic acid (2,6-AQDS) was detected, second-order quenching rate constants with DOM for the triplets of 2-acetonaphthone (2AN) and 3-methoxyacetophenone (3MAP) in the range of 1.30-3.85 × 10(7) L mol(C)(-1) s(-1) were determined. On the basis of the average molecular weight of DOM molecules, the quenching for these uncharged excited triplet molecules is nearly diffusion-controlled, but significant quenching (>10%) in aerated water is not expected to occur below DOM concentrations of 22-72 mg(C) L(-1).
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Affiliation(s)
- Jannis Wenk
- Eawag, Swiss Federal Institute of Aquatic Science and Technology CH-8600, Dübendorf, Switzerland
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Whidbey CM, Daumit KE, Nguyen TH, Ashworth DD, Davis JCC, Latch DE. Photochemical induced changes of in vitro estrogenic activity of steroid hormones. WATER RESEARCH 2012; 46:5287-5296. [PMID: 22877877 DOI: 10.1016/j.watres.2012.07.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 06/27/2012] [Accepted: 07/10/2012] [Indexed: 06/01/2023]
Abstract
Steroid estrogens are endocrine disrupting contaminants frequently detected in natural waters. Because these estrogens can elicit significant biological responses in aquatic organisms, it is important to study their rates and pathways of degradation in natural waters and to identify whether the transformation products retain biological activity. Photochemical kinetics experiments were conducted under simulated solar light for the hormones 17β-estradiol (E2), 17α-ethinylestradiol (EE2), estrone (E1), equilin (EQ), and equilenin (EQN) under direct and indirect photolysis conditions. All of these hormones were susceptible to direct photodegradation, with half-lives ranging from 40 min for E1 to about 8 h for E2 and EE2. Indirect photolysis experiments with added Suwannee River fulvic acid (SRFA) lead to faster degradation rates for E2, EE2, and EQ. Added SRFA caused slower photodegradation rates for E1 and EQN, indicating that it acts primarily as an inner filter for these analytes. The well-established yeast estrogen screen (YES) was used to measure the estrogenicity of the analytes and their photoproducts. Results of YES assay experiments show that only the direct photolysis of E1 gave estrogenic products. Lumiestrone, the major E1 direct photolysis product, was isolated and characterized. It formed in 53% yield and exhibited moderate estrogenic activity. When photolysed in the presence of perinaphthenone, a potent synthetic sensitizer, E1 degraded via an indirect photolysis pathway and did not produce lumiestrone or any other active products. These results suggest that under typical natural water conditions photochemical reactions of E2, EE2, EQ, and EQN are expected to produce inactive products while E1 will give the estrogenic product lumiestrone in moderate yield.
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Affiliation(s)
- Christopher M Whidbey
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA
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Guerard JJ, Chin YP. Photodegradation of ormetoprim in aquaculture and stream-derived dissolved organic matter. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:9801-9806. [PMID: 22950359 DOI: 10.1021/jf302564d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ormetoprim (OMP) is an antibiotic approved for use in the United States to prevent the spread of disease in freshwater aquaculture. It has been shown in the previous literature to be photochemically stable to direct photolysis, but the role of photosensitization processes in the presence of dissolved organic matter (DOM) on the rate of degradation is not well understood. The present results show that water and DOM (specifically the fulvic acid fraction) isolated from a eutrophic aquaculture catfish pond and a nearby stream (Deer Creek) at the Mississippi State University Delta Research and Extension Center facility in Stoneville, MS, significantly increased the phototransformation of OMP relative to direct photolysis. Similar results were reported for reference fulvic acids obtained from the International Humic Substances Society. Results from a combination of scavenging experiments and experiments conducted under anoxic conditions indicate the indirect photodegradation pathway occurs by hydroxyl radical, singlet oxygen attack, and reaction with triplet excited-state DOM.
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Affiliation(s)
- Jennifer J Guerard
- School of Earth Sciences, 125 South Oval Mall, The Ohio State University , Columbus, Ohio 43210, USA
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