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Lu Y, Chow MK, Sun J, Tao D, Jin Q, Ren Y, Wang WX, He Y. Identification of Transformation Products of Organic UV Filters by Photooxidation and Their Differential Estrogenicity Assessment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17110-17122. [PMID: 37851929 DOI: 10.1021/acs.est.3c05015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Organic ultraviolet filters (OUVFs) are extensively released into aquatic environments, where they undergo complex phototransformation. However, there is little knowledge regarding their transformation products (TPs) and associated endocrine disruption potentials. In the present study, we characterized the chemical and toxicological profiles of TPs for two common OUVFs, oxybenzone (BP3) and ethylhexyl methoxycinnamate (EHMC), by photooxidation under environmentally relevant conditions. It is hypothesized that TPs of the tested OUVFs will show varied estrogenicity at different reaction times. High-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) identified 17 TPs of 7 m/z for BP-3 and 13 TPs of 8 m/z for EHMC at confidence levels ≤2. Five novel TPs of 2 m/z were reported for the first time with structure-diagnostic MS/MS spectra. Estrogenicity assessment using the MCF-7-luc cell line showed discrepant estrogenic activities exhibited by OUVF-TPs over time. Specifically, BP3-TPs exhibited significantly greater estrogenicity than the parent at several reaction times, whereas EHMC-TPs displayed fluctuating estrogenicity with a declining trend. Correlation analysis coupled with molecular docking simulations further suggested several TPs of BP3 as potential endocrine disruptive compounds. These findings underscore the necessity of considering mixtures during chemical testing and risk assessment and highlight the potentially greater risks associated with post-transformation cocktails.
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Affiliation(s)
- Yichun Lu
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Man Kwan Chow
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Jiaji Sun
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Danyang Tao
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Qianqian Jin
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yuan Ren
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Yuhe He
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong SAR, China
- Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
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Massano M, Salomone A, Gerace E, Alladio E, Vincenti M, Minella M. Wastewater surveillance of 105 pharmaceutical drugs and metabolites by means of ultra-high-performance liquid-chromatography-tandem high resolution mass spectrometry. J Chromatogr A 2023; 1693:463896. [PMID: 36868084 DOI: 10.1016/j.chroma.2023.463896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/27/2023]
Abstract
Water pollution from pharmaceutical drugs is becoming an environmental issue of increasing concern, making water quality monitoring a crucial priority to safeguard public health. In particular, the presence of antidepressants, benzodiazepines, antiepileptics, and antipsychotics require specific attention as they are known to be harmful to aquatic biota. In this study, a multi-class comprehensive method for the detection of 105 pharmaceutical residues in small (30 mL) water samples was developed according to fit-for-purpose criteria and then applied to provide wide screening of samples obtained from four Wastewater Treatment Plants (WWTPs) in northern Italy. The filtered samples (0.22 µm filters) were extracted by SPE, and then eluted. 5 µL of the concentrated samples were analyzed by a UHPLC-QTOF-HRMS method validated for screening purposes. Adequate sensitivity was recorded for all target analytes, with limits of detection below 5 ng/L for 76 out of 105 analytes. A total of 23 out of the 105 targeted pharmaceutical drugs was detected in all samples. Several further compounds were detected over wide concentration intervals, ranging from ng/L to µg/L. In addition, the retrospective analysis of full-scan QTOF-HRMS data was exploited to carry out an untargeted screening of some drugs' metabolites. As a proof of concept, it was investigated the presence of the carbamazepine metabolites, which is among the most frequently detected contaminants of emerging concern in wastewater. Thanks to this approach, 10,11-dihydro-10-hydroxycarbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine and carbamazepine-10,11-epoxide were identified, the latter requiring particular attention, since it exhibits antiepileptic properties similar to carbamazepine and potential neurotoxic effects in living organism.
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Affiliation(s)
- Marta Massano
- Department of Chemistry, University of Turin, Italy; Centro Regionale Antidoping, Orbassano, TO, Italy.
| | - Alberto Salomone
- Department of Chemistry, University of Turin, Italy; Centro Regionale Antidoping, Orbassano, TO, Italy
| | | | - Eugenio Alladio
- Department of Chemistry, University of Turin, Italy; Centro Regionale Antidoping, Orbassano, TO, Italy
| | - Marco Vincenti
- Department of Chemistry, University of Turin, Italy; Centro Regionale Antidoping, Orbassano, TO, Italy
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3
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Guo Z, Kodikara D, Albi LS, Hatano Y, Chen G, Yoshimura C, Wang J. Photodegradation of organic micropollutants in aquatic environment: Importance, factors and processes. WATER RESEARCH 2023; 231:118236. [PMID: 36682233 DOI: 10.1016/j.watres.2022.118236] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 06/17/2023]
Abstract
Photochemical reactions widely occur in the aquatic environment and play fundamental roles in aquatic ecosystems. In particular, solar-induced photodegradation is efficient for many organic micropollutants (OMPs), especially those that cannot undergo hydrolysis or biodegradation, and thus can mitigate chemical pollution. Recent reports indicate that photodegradation may play a more important role than biodegradation in many OMP transformations in the aquatic environment. Photodegradation can be influenced by the water matrix such as pH, inorganic ions, and dissolved organic matter (DOM). The effect of the water matrix such as DOM on photodegradation is complex, and new insights concerning the disparate effects of DOM have recently been reported. In addition, the photodegradation process is also influenced by physical factors such as latitude, water depth, and temporal variations in sunlight as these factors determine the light conditions. However, it remains challenging to gain an overview of the importance of photodegradation in the aquatic environment because the reactions involved are diverse and complex. Therefore, this review provides a concise summary of the importance of photodegradation and the major processes related to the photodegradation of OMPs, with particular attention given to recent progress on the major reactions of DOM. In addition, major knowledge gaps in this field of environmental photochemistry are highlighted.
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Affiliation(s)
- Zhongyu Guo
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Dilini Kodikara
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Luthfia Shofi Albi
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Yuta Hatano
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Guo Chen
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
| | - Chihiro Yoshimura
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan.
| | - Jieqiong Wang
- Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan 523808, China
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Luo N, Gao Y, Wang M, Niu X, Li G, An T. A new bi-radical species formed during the photochemical degradation of synthetic musk tonalide in water: Study of in-situ laser flash photolysis and validation of synthesized standard sample. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 859:160311. [PMID: 36403842 DOI: 10.1016/j.scitotenv.2022.160311] [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: 09/26/2022] [Revised: 11/15/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
The ubiquitous presence of synthetic musks is causing serious concern due to the species produced from their transformation and environmental impacts. In this study, tonalide was selected as a representative synthetic musk to evaluate the transformation mechanism and pathway in water under ultraviolet (UV) irradiation. The results showed that tonalide could undergo rapid photochemical degradation through a new pivotal bi-radical, which acts as the initial active species. The bi-radicals with a typical absorption peak at 340 nm was observed by in-situ laser flash photolysis technology, and the absolute decay rate constant was obtained as 3.61 ± 0.01 × 109 M-1 s-1 with the life-time of 83.3 ns. The photochemical degradation by-products of tonalide were also identified by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry, and the precise structures of key by-products have been validated by our preparative synthesized standard samples confirmed by nuclear magnetic resonance. Thus, the mechanism of tonalide photochemical degradation, continuous photoenolization of the bi-radicals and followed cycloaddition reaction with O2, was proposed as the predominant pathway. The main degradation by-product, photoenol which has a higher bioconcentration than that of tonalide, was found to form from the bi-radicals photoenolization. This study is the first work to propose a new bi-radical as the photoenol precursors during photochemical degradation of tonalide in water.
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Affiliation(s)
- Na Luo
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Yanpeng Gao
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Mei Wang
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaolin Niu
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Guiying Li
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Taicheng An
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
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5
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Lin J, Zhang K, Jiang L, Hou J, Yu X, Feng M, Ye C. Removal of chloramphenicol antibiotics in natural and engineered water systems: Review of reaction mechanisms and product toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:158059. [PMID: 35985581 DOI: 10.1016/j.scitotenv.2022.158059] [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: 06/18/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Chloramphenicol antibiotics are widely applied in human and veterinary medicine. They experience natural attenuation and/or chemical degradation during oxidative water treatment. However, the environmental risks posed by the transformation products of such organic contaminants remain largely unknown from the literature. As such, this review aims to summarize and analyze the elimination efficiency, reaction mechanisms, and resulting product risks of three typical chloramphenicol antibiotics (chloramphenicol, thiamphenicol, and florfenicol) from these transformation processes. The obtained results suggest that limited attenuation of these micropollutants is observed during hydrolysis, biodegradation, and photolysis. Comparatively, prominent abatement of these compounds is accomplished using advanced oxidation processes; however, efficient mineralization is still difficult given the formation of recalcitrant products. The in silico prediction on the multi-endpoint toxicity and biodegradability of different products is systematically performed. Most of the transformation products are estimated with acute and chronic aquatic toxicity, genotoxicity, and developmental toxicity. Furthermore, the overall reaction mechanisms of these contaminants induced by multiple oxidizing species are revealed. Overall, this review unveils the non-overlooked and serious secondary risks and biodegradability recalcitrance of the degradation products of chloramphenicol antibiotics using a combined experimental and theoretical method. Strategic improvements of current treatment technologies are strongly recommended for complete water decontamination.
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Affiliation(s)
- Jiang Lin
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Kaiting Zhang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Linke Jiang
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Jifei Hou
- School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
| | - Xin Yu
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China
| | - Mingbao Feng
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China.
| | - Chengsong Ye
- Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment & Ecology, Xiamen University, Xiamen 361102, China.
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6
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Li Y, Qin H, Wang L, Lu J, Chovelon JM, Zhou Q, Ji Y. Aquatic photolysis of 2,4-dichloro-6-nitrophenol-the toxic nitrated byproduct of 2,4-dichlorophenol. CHEMOSPHERE 2022; 291:132986. [PMID: 34801574 DOI: 10.1016/j.chemosphere.2021.132986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/16/2021] [Accepted: 11/17/2021] [Indexed: 06/13/2023]
Abstract
2,4-Dichloro-6-nitrophenol (DCNP) is a toxic nitrated byproduct of 2,4-dichlorophenol (2,4-DCP) commonly found in agriculturally impacted waters (e.g., paddy waters). DCNP has both genotoxicity and developmental toxicity and can cause endocrine disrupting effects on aquatic species. Herein, we investigated the photolysis of DCNP under UV254 irradiation in aqueous solutions. Results show that the anionic form of DCNP (DCNP-) is more photoreactive than the neutral form (DCNP0) due to its higher molar absorption coefficient and quantum yield. The presence of Suwannee River natural organic matter (SRNOM) inhibits the direct photolysis of DCNP through light screening. A series of photoproducts were identified by solid phase extraction (SPE) and high resolution-mass spectrometry (HR-MS) analysis. The photolysis of DCNP generates several photoproducts, including photoreduction, photonucleophilic substitution, photoionization, and dimerization intermediates. The primary photochemical mechanisms include photoionization from the singlet state and heterolytic C-Cl bond splitting in the triplet state. This contribution may shed some light on the photochemical transformation and fate of DCNP in UV-based engineering systems or natural sunlit surface waters.
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Affiliation(s)
- Yunong Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hao Qin
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lixiao Wang
- 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
| | - Quansuo Zhou
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Yuefei Ji
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
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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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8
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Zhang S, Ye C, Li J, Yu X, Feng M. Treatment-driven removal efficiency, product formation, and toxicity evolution of antineoplastic agents: Current status and implications for water safety assessment. WATER RESEARCH 2021; 206:117729. [PMID: 34624659 DOI: 10.1016/j.watres.2021.117729] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/26/2021] [Accepted: 09/26/2021] [Indexed: 06/13/2023]
Abstract
Antineoplastic compounds, designed for chemotherapeutic anticancer therapy, have become emerging contaminants of global concern over the past decade due to their ubiquitous occurrence, environmental persistence, and multiple adverse effects on aquatic ecosystems. Increasing efforts have been devoted to developing efficient strategies for remediating water containing these micropollutants. In this study, the physicochemical properties, natural attenuation, and chemical reactivity with aqueous oxidizing species of five antineoplastic drugs with the highest environmental prevalence (i.e., tamoxifen, cyclophosphamide, ifosfamide, 5-fluorouracil, and methotrexate) were summarized. The removal performance, transformation products (TPs) of varying structures, overall reaction pathways, and toxicity evolution during different treatments were evaluated and discussed. Additionally, the biodegradability and multi-endpoint toxicity of each TP were predicted using in silico QSAR software. Depending on their distinct inherent structures, the reactivity of the antineoplastics with oxidizing species varied, with hydroxyl radicals exhibiting unparalleled merits in rapid oxidation. Complete elimination of these contaminants was observed during oxidative treatments, but with inadequate mineralization. Notably, the increase in toxicity within multiple processes was determined based on both experimental bioassays and theoretical predictions. This may be attributed to the adverse effects induced by the large number of identified and unknown TPs individually and in combination. Together with the environmental persistence and low biodegradability of most TPs, these results necessitate the application of efficient post-treatments in conjunction with a more thorough water safety evaluation (e.g., using high-throughput screening) of the mixtures of treated water and wastewater.
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Affiliation(s)
- Shengqi Zhang
- College of the Environment & Ecology, Xiamen University, Xiamen, PR China
| | - Chengsong Ye
- College of the Environment & Ecology, Xiamen University, Xiamen, PR China
| | - Jianguo Li
- College of the Environment & Ecology, Xiamen University, Xiamen, PR China
| | - Xin Yu
- College of the Environment & Ecology, Xiamen University, Xiamen, PR China
| | - Mingbao Feng
- College of the Environment & Ecology, Xiamen University, Xiamen, PR China.
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9
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Yuan C, Tebes-Stevens C, Weber EJ. Prioritizing Direct Photolysis Products Predicted by the Chemical Transformation Simulator: Relative Reasoning and Absolute Ranking. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5950-5958. [PMID: 33881833 PMCID: PMC8269956 DOI: 10.1021/acs.est.0c08745] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The United States Environmental Protection Agency's Chemical Transformation Simulator (CTS) platform implemented the first freely available reaction library to predict direct photolysis products of organic contaminants in aquatic systems. However, the initial version of the reaction library did not differentiate the formation likelihood of each predicted product, and therefore, the number of predicted products that are not observed tended to exponentially increase with the prediction generation. To alleviate this problem, we first employed relative reasoning algorithms to remove unlikely products. We then ranked different reaction schemes according to their transformation kinetics and removed slowly forming products. Applying the two strategies improved the precision (the percentage of correctly predicted products over all predicted products) by 34% and 53% for the internal evaluation set and the external evaluation set, respectively, when products from three generations were considered. This improved library also revealed new research directions to improve predictions of the dominant phototransformation products.
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Affiliation(s)
- Chenyi Yuan
- Oak Ridge Institute for Science and Education (ORISE), hosted at United States Environmental Protection Agency, Athens, Georgia 30605, United States
| | - Caroline Tebes-Stevens
- Center for Environmental Measurement and Modeling, United States Environmental Protection Agency, Athens, Georgia 30605, United States
| | - Eric J. Weber
- Center for Environmental Measurement and Modeling, United States Environmental Protection Agency, Athens, Georgia 30605, United States
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10
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Wang X, Pu L, Liu C, Gao J, Gu C. Enhanced and selective phototransformation of chlorophene on aluminum hydroxide-humic complexes. WATER RESEARCH 2021; 193:116904. [PMID: 33582491 DOI: 10.1016/j.watres.2021.116904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/30/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Mineral-humic complexes, known as mineral-associated organic matter (MAOM), are ubiquitous in natural waters. However, the interaction between organic pollutants and MAOM remains elusive, which may affect their degradation process. In this study, photochemical transformation of chlorophene (CP) in the presence of MAOM, prepared by coating aluminum hydroxide with humic acid (HA-HAO), was investigated. Our results showed that the degradation of CP was significantly enhanced in the presence of HA-HAO, and the degradation rate constant was ~5 times as that with HA only. It was because the adsorption of CP to HA-HAO particles was greatly enhanced, and concentration of reactive oxygen species (ROS) was increased on HA-HAO surfaces, which further promoted the reactions between CP and ROS. The quenching experiments combined with EPR technology confirmed that superoxide anion (O2·-) was the primary reactive radical on CP photodegradation. More importantly, the degradation of CP with HA-HAO followed a hydroxylation process, rather than the oligomerization reaction with HA only. Spectroscopic analysis provided direct evidence for the formation of hydrogen bonding between CP phenolic hydroxyl group and surface oxygen of HAO, which would suppress the reactivity of phenolic hydroxyl group, consequently the ortho- and meta-positions of CP became more facile for the hydroxylation reaction. This study shows the importance of MAOM in altering the photochemical behavior and transformation pathway of organic contaminants.
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Affiliation(s)
- Xinghao Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Lirong Pu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Cun Liu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Juan Gao
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China.
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Lei Y, Lei X, Westerhoff P, Zhang X, Yang X. Reactivity of Chlorine Radicals (Cl • and Cl 2•-) with Dissolved Organic Matter and the Formation of Chlorinated Byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:689-699. [PMID: 33346661 DOI: 10.1021/acs.est.0c05596] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Chlorine radicals, including Cl• and Cl2•-, can be produced in sunlight waters (rivers, oceans, and lakes) or water treatment processes (e.g., electrochemical and advanced oxidation processes). Dissolved organic matter (DOM) is a major reactant with, or a scavenger of, Cl• and Cl2•- in water, but limited quantitative information exists regarding the influence of DOM structure on its reactivity with Cl• and Cl2•-. This study aimed at quantifying the reaction rates and the formation of chlorinated organic byproducts produced from Cl• and Cl2•- reactions with DOM. Laser flash photolysis experiments were conducted to quantify the second-order reaction rate constants of 19 DOM isolates with Cl• (kDOM-Cl•) and Cl2•- (kDOM-Cl2•-), and compare those with the hydroxyl radical rate constants (kDOM-•OH). The values for kDOM-Cl• ((3.71 ± 0.34) × 108 to (1.52 ± 1.56) × 109 MC-1 s-1) were orders of magnitude greater than the kDOM-Cl2•- values ((4.60 ± 0.90) × 106 to (3.57 ± 0.53) × 107 MC-1 s-1). kDOM-Cl• negatively correlated with the weight-averaged molecular weight (MW) due to the diffusion-controlled reactions. DOM with high aromaticity and total antioxidant capacity tended to react faster with Cl2•-. During the same experiments, we also monitored the formation of chlorinated byproducts through the evolution of total organic chlorine (TOCl) as a function of chlorine radical oxidant exposure (CT value). Maximum TOCl occurred at a CT of 4-8 × 10-12 M·s for Cl• and 1.1-2.2 × 10-10 M·s for Cl2•-. These results signify the importance of DOM in scavenging chlorine radicals and the potential risks of producing chlorinated byproducts of unknown toxicity.
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Affiliation(s)
- Yu Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Paul Westerhoff
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona 85287-3005, United States
| | - Xinran Zhang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
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