1
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Freeman D, Nelson RK, Pate K, Reddy CM, Ward CP. Forecasting Photo-Dissolution for Future Oil Spills at Sea: Effects of Oil Properties and Composition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58. [PMID: 39137011 PMCID: PMC11361275 DOI: 10.1021/acs.est.4c05169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 08/16/2024]
Abstract
Photo-dissolution, the photochemical production of water-soluble species from oil, can transfer oil-derived dissolved organic carbon (DOC) from floating surface slicks to the underlying seawater. Photo-dissolution was likely a quantitatively relevant fate process for the Macondo crude oil spilled during the 2010 Deepwater Horizon spill, but the importance of photo-dissolution for other oils is poorly constrained. This study evaluated the photo-dissolution reactivities (apparent quantum yields) and modeled rates for oils with diverse physical properties and chemical compositions, including an ultra low sulfur fuel oil (ULSFO). Photo-dissolution from UV (310 nm) light was strongly positively correlated with the fraction of small, gas-oil range compounds (
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Affiliation(s)
- Danielle
Haas Freeman
- MIT-WHOI
Joint Program in Oceanography/Applied Ocean Science & Engineering, Woods Hole, Massachusetts 02543, United States
- Department
of Marine Chemistry and Geochemistry, Woods
Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Robert K. Nelson
- Department
of Marine Chemistry and Geochemistry, Woods
Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Kali Pate
- Department
of Marine Chemistry and Geochemistry, Woods
Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Christopher M. Reddy
- Department
of Marine Chemistry and Geochemistry, Woods
Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Collin P. Ward
- Department
of Marine Chemistry and Geochemistry, Woods
Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
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2
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Zhou C, Wu B, Zheng X, Chen B, Chu C. Wavelength-dependent direct and indirect photochemical transformations of organic pollutants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:170414. [PMID: 38272084 DOI: 10.1016/j.scitotenv.2024.170414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 01/27/2024]
Abstract
Sunlight-induced photochemical transformations greatly affect the persistence of organic pollutants in natural environment. Whereas sunlight intensity is well-known to affect pollutant phototransformation rates, the reliance of pollutant phototransformation kinetics on sunlight spectrum remains poorly understood, which may greatly vary under different spatial-temporal, water matrix, and climatic conditions. Here, we systematically assessed the wavelength-dependent direct and indirect phototransformations of 12 organic pollutants. Their phototransformation rates dramatically decreased with light wavelength increasing from 375 to 632 nm, with direct photolysis displaying higher wavelength-dependence than indirect photolysis. Remarkably, UV light dominated both direct (90.4-99.5 %) and indirect (64.6-98.7 %) photochemical transformations of all investigated organic pollutants, despite its minor portion in sunlight spectrum (e.g., 6.5 % on March 20 at the equator). Based on wavelength-dependent rate constant spectrum, the predicted phototransformation rate of chloramphenicol (4.5 ± 0.7 × 10-4 s-1) agreed well with the observed rate under outdoor sunlight irradiation (4.3 ± 0.0 × 10-4 s-1), and there is no significant difference between the predicted rate and the observed rate (p-value = 0.132). Moreover, rate constant and quantum yield coefficient (QYC) spectrum could be applied for facilely investigate the influence of spectral changes on the phototransformation of pollutants under varying spatial-temporal (e.g., season, latitude) and climatic conditions (e.g., cloud cover). Our study highlights the wavelength-dependence of both direct and indirect phototransformation of pollutants, and the UV part of natural sunlight plays a decisive role in the phototransformation of pollutants.
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Affiliation(s)
- Chong Zhou
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Binbin Wu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Xiaoshan Zheng
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Chiheng Chu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China.
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3
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Um M, Fan L, Jones OAH, Roddick F. A comparative study of programs to predict direct photolysis rates in wastewater systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168921. [PMID: 38040346 DOI: 10.1016/j.scitotenv.2023.168921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/22/2023] [Accepted: 11/25/2023] [Indexed: 12/03/2023]
Abstract
A wide range of contaminants of emerging concern (CECs) are known to photodegrade in the surface layers of natural waters and wastewater systems. Computer programs such as GCSolar, ABIWAS, APEX, EXAMS and WASP model the direct photolysis rates and half-lives of CECs, usually as a function of the solar irradiance, water molar light extinction, chemical molar light absorption and reaction quantum yield. These programs have been used extensively for studies in natural water systems in the northern hemisphere. However, their applicability to wastewater treatment systems such as waste stabilisation ponds and/or southern hemisphere conditions is not well studied. Here we present a comparative review of the major software used and their potential applicability to predicting direct photolysis rates and half-lives in wastewater. The newer equivalent monochromatic wavelength, approach, which enables the approximation of polychromatic photodegradation via a monochromatic wavelength is also discussed. Current software appears to be less suitable for modelling photodegradation in wastewater systems in the southern hemisphere than the northern hemisphere as their internal databases are based on data from natural waters in the northern hemisphere. This may be because there have been few attempts to model CEC photolysis in wastewater systems, particularly in the southern hemisphere. This indicates that either new software needs to be developed, or these programs need to be updated with data on wastewater matrices and/or the southern hemisphere. We anticipate this review will promote the adaptation of these programs as tools to further the understanding CEC photodegradation in wastewater treatment plants.
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Affiliation(s)
- Michelle Um
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Linhua Fan
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Oliver A H Jones
- School of Science, RMIT University, Bundoora West Campus, 71, Bundoora, Victoria 3083, Australia.
| | - Felicity Roddick
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
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4
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Madhiyan M, Moor KJ. Singlet Oxygen Quantum Yields of Pyrogenic Dissolved Organic Matter from Lab-Prepared and Wildfire Chars. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1265-1273. [PMID: 38157474 DOI: 10.1021/acs.est.3c03976] [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: 01/03/2024]
Abstract
Wildfires or prescribed fires release pyrogenic dissolved organic matter (pyDOM) into the environment, which can photochemically produce singlet oxygen (1O2) in sun-lit surface waters. 1O2 quantum yields (ΦΔ) are well-studied for non-pyrogenic DOM, but little is understood about the 1O2 generation from pyDOM, especially the ΦΔ values from real wildfire samples and their wavelength dependence. In this study, time-resolved 1O2 phosphorescence was used to determine the wavelength-dependent ΦΔ values for pyDOM generated from wildfire char and a series of lab-prepared chars produced by combusting oak and pine wood. Wildfire and most lab-prepared pyDOM generally had similar ΦΔ values (2.1-2.7%) at 365 nm compared to the reference Suwannee River Natural Organic Matter (SRNOM) isolate (2.4%). Interestingly, pyDOM from the highest combustion temperature char was found to possess extremely low ΦΔ values compared to SRNOM and other pyDOM at all excitation wavelengths. In addition, it was revealed that the predicted steady-state concentration of 1O2 from pyDOM was similar to that from SRNOM, indicating that the addition of pyDOM from wood chars may not strongly impact surface water photochemistry.
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Affiliation(s)
- Monika Madhiyan
- Utah Water Research Laboratory, Department of Civil and Environmental Engineering, Utah State University, Logan, Utah 84322, United States
| | - Kyle J Moor
- Utah Water Research Laboratory, Department of Civil and Environmental Engineering, Utah State University, Logan, Utah 84322, United States
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5
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Guo Z, Wang T, Chen G, Wang J, Fujii M, Yoshimura C. Apparent quantum yield for photo-production of singlet oxygen in reservoirs and its relation to the water matrix. WATER RESEARCH 2023; 244:120456. [PMID: 37579568 DOI: 10.1016/j.watres.2023.120456] [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: 06/02/2023] [Revised: 07/21/2023] [Accepted: 08/06/2023] [Indexed: 08/16/2023]
Abstract
Man-made reservoirs are important for human daily lives and offer different functions, however they are contaminated due to anthropogenic activities. Dissolved organic matter (DOM) from each reservoir is unique in composition, which further determines its photo-reactivity. Thus, this study aimed to investigate the photo-reactivity of reservoir DOM in terms of the quantum yield for photo-production of singlet oxygen (Ф1O2). We sampled surface water of 50 reservoirs in Japan and determined their Ф1O2 using simulated sunlight together with bulk water analysis. Their Ф1O2 ranged from 1.46 × 10-2 to 6.21 × 10-2 (mean, 2.55 × 10-2), which was identical to those of lakes and rivers reported in the literature, but lower than those of wetland water and wastewater. High-energy triplet-state of DOM accounted for 59.4% of the 1O2 production in the reservoir water on average. Among the bulk water properties, the spectral slope of wavelength from 350 to 400 nm (S350-400) was statistically detected as the most important predictor for Ф1O2. Furthermore, the multiple linear regression model employed S350-400 and the biological index as predictors with no intercorrelations and reasonable accuracy (r2 = 0.86), while the random forest model showed a better accuracy (r2 = 0.90). Overall, these major findings are beneficial for understanding the photo-reactivity of reservoir waters.
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Affiliation(s)
- Zhongyu Guo
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-Ku, Tokyo, 152-8552, Japan
| | - Tingting Wang
- Graduate School of Science, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, 464-8602, Japan
| | - Guo Chen
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-Ku, Tokyo, 152-8552, Japan
| | - Jieqiong Wang
- College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Manabu Fujii
- 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.
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6
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Freeman DH, Niles SF, Rodgers RP, French-McCay DP, Longnecker K, Reddy CM, Ward CP. Hot and Cold: Photochemical Weathering Mediates Oil Properties and Fate Differently Depending on Seawater Temperature. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11988-11998. [PMID: 37515555 DOI: 10.1021/acs.est.3c02962] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2023]
Abstract
Photochemical weathering transforms petroleum oil and changes its bulk physical properties, as well as its partitioning into seawater. This transformation process is likely to occur in a cold water marine oil spill, but little is known about the behavior of photochemically weathered oil in cold water. We quantified the effect of photochemical weathering on oil properties and partitioning across temperatures. Compared to weathering in the dark, photochemical weathering increases oil viscosity and water-soluble content, decreases oil-seawater interfacial tension, and slightly increases density. Many of these photochemical changes are much larger than changes caused by evaporative weathering. Further, the viscosity and water-soluble content of photochemically weathered oil are more temperature-sensitive compared to evaporatively weathered oil, which changes the importance of key fate processes in warm versus cold environments. Compared to at 30 °C, photochemically weathered oil at 5 °C would have a 16× higher viscosity and a 7× lower water-soluble content, resulting in lower entrainment and dissolution. Collectively, the physical properties and thus fate of photochemically weathered oil in a cold water spill may be substantially different from those in a warm water spill. These differences could affect the choice of oil spill response options in cold, high-light environments.
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Affiliation(s)
- Danielle Haas Freeman
- MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering, Woods Hole, Massachusetts 02543, United States
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Sydney F Niles
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Ryan P Rodgers
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | | | - Krista Longnecker
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Christopher M Reddy
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Collin P Ward
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
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7
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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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8
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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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9
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Partanen S, McNeill K. Global Corrections to Reference Irradiance Spectra for Non-Clear-Sky Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2682-2690. [PMID: 36735549 PMCID: PMC9933536 DOI: 10.1021/acs.est.2c07359] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/06/2023] [Accepted: 01/06/2023] [Indexed: 05/28/2023]
Abstract
Photochemical reactions in surface waters play important roles in element cycling and in the removal of organic contaminants, among other processes. A central environmental variable affecting photochemical processes in surface waters is the incoming solar irradiance, as this initiates these processes. However, clear-sky incident irradiance spectra are often used when evaluating the fate of aquatic contaminants, leading to an overestimation of contaminant decay rates due to photochemical transformation. In this work, incident irradiance satellite data were used to develop global-scale non-clear-sky correction factors for commonly used reference irradiance spectra. Non-clear-sky conditions can decrease incident irradiance by over 90% depending on the geographic location and time of the year, with latitudes above 40°N being most heavily affected by seasons. The impact of non-clear-sky conditions on contaminant half-lives was illustrated in a case study of triclosan in lake Greifensee, which showed a 39% increase in the triclosan half-life over the course of a year under non-clear-sky conditions. A global annual average correction factor of 0.76 was determined as an approximate way to account for non-clear-sky conditions. The correction factors are developed at monthly and seasonal resolutions for every location on the globe between 70°N and 60°S at a 4 km spatial resolution and can be used by researchers, practitioners, and regulators who need improved estimates of incident irradiance.
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10
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Jaramillo-Fierro X, Cuenca MF. Novel Semiconductor Cu(C 3H 3N 3S 3) 3/ZnTiO 3/TiO 2 for the Photoinactivation of E. coli and S. aureus under Solar Light. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:173. [PMID: 36616082 PMCID: PMC9824406 DOI: 10.3390/nano13010173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/23/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The use of semiconductors for bacterial photoinactivation is a promising approach that has attracted great interest in wastewater remediation. The photoinactivator Cu-TTC/ZTO/TO was synthesized by the solvothermal method from the coordination complex Cu(C3H3N3S3)3 (Cu-TTC) and the hybrid semiconductor ZnTiO3/TiO2 (ZTO/TO). In this study, the effect of photocatalyst composition/concentration as well as radiation intensity on the photoinactivation of the gram-negative bacteria Escherichia coli and the gram-positive bacteria Staphylococcus aureus in aqueous solutions was investigated. The results revealed that 25 mg/mL of photoinactivator, in a Cu-TTC:ZTO/TO molar ratio of 1:2 (w/w%) presents a higher rate of bacterial photoinactivation under simulated solar light (λ = 300-800 nm) in comparison to the individual components. The evidence of this study suggests that the presence of the Cu(C3H3N3S3)3 coordination complex in the ZnTiO3/TiO2 hybrid semiconductor would contribute to the generation of reactive oxygen species (ROS) that are essential to initiate the bacterial photoinactivation process. Finally, the results obtained allow us to predict that the Cu-TTC/ZTO/TO photocatalyst could be used for effective bacterial inactivation of E. coli and S. aureus in aqueous systems under simulated solar light.
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Affiliation(s)
- Ximena Jaramillo-Fierro
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Loja 1101608, Ecuador
| | - María Fernanda Cuenca
- Departamento de Producción, Facultad de Ciencias Exactas y Naturales, Universidad Técnica Particular de Loja, San Cayetano Alto, Loja 1101608, Ecuador
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11
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Sutherland KM, Johnston DT, Hemingway JD, Wankel SD, Ward CP. Revised microbial and photochemical triple-oxygen isotope effects improve marine gross oxygen production estimates. PNAS NEXUS 2022; 1:pgac233. [PMID: 36712381 PMCID: PMC9802178 DOI: 10.1093/pnasnexus/pgac233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/08/2022] [Indexed: 11/05/2022]
Abstract
The biogeochemical fluxes that cycle oxygen (O2) play a critical role in regulating Earth's climate and habitability. Triple-oxygen isotope (TOI) compositions of marine dissolved O2 are considered a robust tool for tracing oxygen cycling and quantifying gross photosynthetic O2 production. This method assumes that photosynthesis, microbial respiration, and gas exchange with the atmosphere are the primary influences on dissolved O2 content, and that they have predictable, fixed isotope effects. Despite its widespread use, there are major elements of this approach that remain uncharacterized, including the TOI dynamics of respiration by marine heterotrophic bacteria and abiotic O2 sinks such as the photochemical oxidation of dissolved organic carbon (DOC). Here, we report the TOI fractionation for O2 utilization by two model marine heterotrophs and by abiotic photo-oxidation of representative terrestrial and coastal marine DOC. We demonstrate that TOI slopes associated with these processes span a significant range of the mass-dependent domain (λ = 0.499 to 0.521). A sensitivity analysis reveals that even under moderate productivity and photo-oxidation scenarios, true gross oxygen production may deviate from previous estimates by more than 20% in either direction. By considering a broader suite of oxygen cycle reactions, our findings challenge current gross oxygen production estimates and highlight several paths forward to better understanding the marine oxygen and carbon cycles.
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Affiliation(s)
| | - David T Johnston
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Jordon D Hemingway
- ETH Zürich, Geological Institute, Department of Earth Sciences, Zürich 8092, Switzerland
| | - Scott D Wankel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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12
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Fennell BD, Odorisio A, McKay G. Quantifying Hydrated Electron Transformation Kinetics in UV-Advanced Reduction Processes Using the Re-,UV Method. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10329-10338. [PMID: 35791772 DOI: 10.1021/acs.est.2c02003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ultraviolet advanced reduction processes (UV-ARP) have garnered significant attention recently for the degradation of several hard to treat contaminants, including recalcitrant per- and polyfluoroalkyl substances (PFAS). The rate of contaminant degradation in UV-ARP is directly related to the available hydrated electron concentration ([eaq-]). However, reports of [eaq-] and other parameters typically used to characterize photochemical systems are not widely reported in the UV-ARP literature. Deploying monochloroacetate as a probe compound, we developed a method (Re-,UV) to quantify the time-based hydrated electron concentration ([eaq]t) available for contaminant degradation relative to inputted UV fluence. Measured [eaq]t was then used to understand the impact of eaq- rate of formation and scavenging capacity on the degradation of two contaminants─nitrate and perfluorooctane sulfonate (PFOS)─in four source waters with varying background water quality. The results show that the long-term treatability of PFOS by UV-ARP is not significantly impacted by the initial eaq- scavenging conditions but rather is influenced by the presence of eaq- scavengers like dissolved organic carbon and bicarbonate. Lastly, using [eaq]t, degradation of nitrate and PFOS was modeled in the source waters. We demonstrate that the Re-,UV method provides an effective tool to assess UV-ARP treatment performance in a variety of source waters.
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Affiliation(s)
- Benjamin D Fennell
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
| | - Adam Odorisio
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
| | - Garrett McKay
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
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13
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Fennell B, Mezyk SP, McKay G. Critical Review of UV-Advanced Reduction Processes for the Treatment of Chemical Contaminants in Water. ACS ENVIRONMENTAL AU 2022; 2:178-205. [PMID: 37102145 PMCID: PMC10114900 DOI: 10.1021/acsenvironau.1c00042] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
UV-advanced reduction processes (UV-ARP) are an advanced water treatment technology characterized by the reductive transformation of chemical contaminants. Contaminant abatement in UV-ARP is most often accomplished through reaction with hydrated electrons (eaq -) produced from UV photolysis of chemical sensitizers (e.g., sulfite). In this Review, we evaluate the photochemical kinetics, substrate scope, and optimization of UV-ARP. We find that quantities typically reported in photochemical studies of natural and engineered systems are under-reported in the UV-ARP literature, especially the formation rates, scavenging capacities, and concentrations of key reactive species like eaq -. The absence of these quantities has made it difficult to fully evaluate the impact of operating conditions and the role of water matrix components on the efficiencies of UV-ARP. The UV-ARP substrate scope is weighted heavily toward contaminant classes that are resistant to degradation by advanced oxidation processes, like oxyanions and per- and polyfluoroalkyl substances. Some studies have sought to optimize the UV-ARP treatment of these contaminants; however, a thorough evaluation of the impact of water matrix components like dissolved organic matter on these optimization strategies is needed. Overall, the data compilation, analysis, and research recommendations provided in this Review will assist the UV-ARP research community in future efforts toward optimizing UV-ARP systems, modeling the eaq --based chemical transformation kinetics, and developing new UV-ARP systems.
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Affiliation(s)
- Benjamin
D. Fennell
- Zachry
Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Stephen P. Mezyk
- Department
of Chemistry and Biochemistry, California
State University, Long Beach, Long Beach, California 90840, United States
| | - Garrett McKay
- Zachry
Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77843, United States
- . Phone: 979-458-6540
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14
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[Cu(C3H3N3S3)3] Adsorption onto ZnTiO3/TiO2 for Coordination-Complex Sensitized Photochemical Applications. MATERIALS 2022; 15:ma15093252. [PMID: 35591585 PMCID: PMC9100386 DOI: 10.3390/ma15093252] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023]
Abstract
Currently, the design of highly efficient materials for photochemical applications remains a challenge. In this study, an efficient semiconductor was prepared, based on a coordination complex (Cu-TTC) of Cu(I) and trithiocyanuric acid on ZnTiO3/TiO2 (ZTO/TO). The Cu-TTC/ZTO/TO composite was prepared by the solvothermal method at room temperature. The structural, optical, and electrochemical characteristics, as well as the photocatalytic performance of the composite, were experimentally and computationally studied. The results show that the Cu-TTC/ZTO/TO composite efficiently extended its photoresponse in the visible region of the electromagnetic spectrum. The electrochemistry of the proposed tautomeric architecture (s-Cu-TTC) clearly reveals the presence of metal–ligand charge-transfer (MLCT) and π → π* excitations. The maximum methylene blue (MB) dye photodegradation efficiency of 95% in aqueous solutions was achieved under the illumination of simulated solar light. Finally, computational calculations based on the Density Functional Theory (DFT) method were performed to determine the electronic properties of the s-Cu-TTC tautomeric structure and clarify the adsorption mechanism of this complex on the surface (101) of both ZnTiO3 and TiO2 oxides. The results obtained allow us to suggest that the Cu-TTC complex is an effective charge carrier and that the Cu-TTC/ZTO/TO composite can be used efficiently for photochemical applications.
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15
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Freeman DH, Ward CP. Sunlight-driven dissolution is a major fate of oil at sea. SCIENCE ADVANCES 2022; 8:eabl7605. [PMID: 35171676 PMCID: PMC8849300 DOI: 10.1126/sciadv.abl7605] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/21/2021] [Indexed: 05/20/2023]
Abstract
Oxygenation reactions initiated by sunlight can transform insoluble components of crude oil at sea into water-soluble products, a process called photo-dissolution. First reported a half century ago, photo-dissolution has never been included in spill models because key parameters required for rate modeling were unknown, including the wavelength and photon dose dependence. Here, we experimentally quantified photo-dissolution as a function of wavelength and photon dose, making possible a sensitivity analysis of environmental variables in hypothetical spill scenarios and a mass balance assessment for the 2010 Deepwater Horizon (DwH) spill. The sensitivity analysis revealed that rates were most sensitive to oil slick thickness, season/latitude, and wavelength and less sensitive to photon dose. We estimate that 3 to 17% (best estimate 8%) of DwH surface oil was subject to photo-dissolution, comparable in magnitude to other widely recognized fate processes. Our findings invite a critical reevaluation of surface oil budgets for both DwH and future spills at sea.
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Affiliation(s)
- Danielle Haas Freeman
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Collin P. Ward
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Corresponding author.
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16
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Nevins MG, Apell JN. Emerging investigator series: quantifying the impact of cloud cover on solar irradiance and environmental photodegradation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1884-1892. [PMID: 34753158 DOI: 10.1039/d1em00314c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Environmental photodegradation is dependent on the solar irradiance that reaches the Earth's surface, and photodegradation half-lives of contaminants are typically estimated assuming clear sky (i.e., cloudless) conditions. In this work, the effect of cloud cover on solar irradiance was investigated. Data from the National Renewable Energy Laboratory (NREL), which spanned 3 years of observations (10/2017 to 12/2020), were used to train two machine learning models to predict irradiance based on three inputs - day of year, time of day, and percentage of the sky that was cloudy. Results showed a non-linear relationship between cloud cover and irradiance. Solar irradiance was minimally impacted up to ≈50% cloud cover but decreased by ≈67% at 100% cloud cover. Both random forest and artificial neural network models performed well with relative root mean squared errors of 26-31%, which varied depending on the source of cloud cover data and the spectral region being modeled. Daily irradiance values for a whole year were predicted for varying cloud conditions using the machine learning models; this result was approximated using a quadratic fit of y = 1 - 0.00243x - (4.24 × 10-5)x2 where y is the fraction of clear sky irradiance expected and x is the percentage of cloud cover in the sky. In addition, the model results supported that there was no wavelength dependence for the effect of cloud cover. Therefore, decreases in both direct and indirect photodegradation rates should be proportional to the decrease in irradiance, which has a non-linear dependence on cloud cover.
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Affiliation(s)
- Michelle G Nevins
- Department of Civil and Urban Engineering, New York University Tandon School of Engineering, 6 MetroTech Center, Brooklyn, NY 11201, USA.
| | - Jennifer N Apell
- Department of Civil and Urban Engineering, New York University Tandon School of Engineering, 6 MetroTech Center, Brooklyn, NY 11201, USA.
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17
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Wu B, Liu T, Wang Y, Zhao G, Chen B, Chu C. High Sample Throughput LED Reactor for Facile Characterization of the Quantum Yield Spectrum of Photochemically Produced Reactive Intermediates. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16204-16214. [PMID: 34553927 DOI: 10.1021/acs.est.1c04608] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Photochemically produced reactive intermediates (PPRIs) by natural photosensitizers such as chromophoric dissolved organic matter (CDOM) play numerous key roles in aquatic biogeochemical processes. PPRI productions rely on both the intensity and the spectrum of incident sunlight. While the impacts of sunlight intensity on PPRI productions are well-studied, there remains insufficient understanding of the spectrum-dependence of PPRI productions. Here we designed a high sample throughput reactor equipped with monochromatic LED lights for systematic assessments of wavelength-dependent productions of four important PPRI species, i.e., triplet-state excited CDOM (3CDOM*), singlet oxygen (1O2), hydrogen peroxide (H2O2), and hydroxyl radical (•OH), in CDOM solutions. The quantum yields of PPRIs followed the order: 3CDOM* > 1O2 ≫ H2O2 > •OH. Moreover, PPRI quantum yields decreased with the light wavelength increasing from 375 to 490 nm and sharply decreased to zero above 490 nm, while the shapes of quantum yield spectra differed among PPRI species. Simulations on PPRI productions under varying season, latitude, altitude, and cloud cover conditions show that the sunlight spectrum plays a role as equally important as intensity in determining PPRI productions and PPRI-mediated transformations of aquatic nutrients and micropollutants. Therefore, incorporating the spectrum dependence of PPRI productions will advance our understandings of PPRI-driven biogeochemical processes and pollutant dynamics under varying spatial-temporal and climatic conditions. Regarding this, the high sample throughput LED reactor sheds light on a new approach for the facile characterization of PPRI quantum yield spectrum.
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Affiliation(s)
- Binbin Wu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Tian Liu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Yanling Wang
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Guoqiang Zhao
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Chiheng Chu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
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18
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Drouin G, Droz B, Leresche F, Payraudeau S, Masbou J, Imfeld G. Direct and indirect photodegradation of atrazine and S-metolachlor in agriculturally impacted surface water and associated C and N isotope fractionation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1791-1802. [PMID: 34709265 DOI: 10.1039/d1em00246e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Knowledge of direct and indirect photodegradation of pesticides and associated isotope fractionation can help to assess pesticide degradation in surface waters. Here, we investigated carbon (C) and nitrogen (N) isotope fractionation during direct and indirect photodegradation of the herbicides atrazine and S-metolachlor in synthetic agriculturally impacted surface waters containing nitrates (20 mg L-1) and dissolved organic matter (DOM, 5.4 mgC L-1). Atrazine and S-metolachlor were quickly photodegraded by both direct and indirect processes (half-lives <5 and <7 days, respectively). DOM slowed down photodegradation while nitrates increased degradation rates. The analysis of transformation products showed that oxidation mediated by hydroxyl radicals (HO˙) predominated during indirect photodegradation. UV light (254 nm) led to significant C and N isotope fractionation, yielding isotopic fractionation values εC = 2.7 ± 0.3 and 0.8 ± 0.1‰, and εN = 2.4 ± 0.3 and -2.6 ± 0.7‰ for atrazine and S-metolachlor, respectively. In contrast, photodegradation under simulated sunlight led to negligible C and slight N isotope fractionation, emphasizing the effect of the radiation wavelengths on the isotope fractionation induced by direct photodegradation. Altogether, these results highlight the importance of using simulated sunlight to obtain environmentally-relevant isotopic fractionation values and to distinguish photodegradation and other dissipation pathways in surface waters.
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Affiliation(s)
- Guillaume Drouin
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Boris Droz
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Frank Leresche
- Department of Civil, Environmental, and Architectural Engineering, Environmental Engineering Program, University of Colorado Boulder, Colorado 80309, USA
| | - Sylvain Payraudeau
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Jérémy Masbou
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
| | - Gwenaël Imfeld
- Institut Terre et Environnement de Strasbourg (ITES), Université de Strasbourg, EOST, ENGEES, CNRS, UMR 7063, 5 rue Descartes, Strasbourg F-67084, France.
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19
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Leresche F, Salazar JR, Pfotenhauer DJ, Hannigan MP, Majestic BJ, Rosario-Ortiz FL. Photochemical Aging of Atmospheric Particulate Matter in the Aqueous Phase. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13152-13163. [PMID: 34529399 DOI: 10.1021/acs.est.1c00978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This study focused on the photoaging of atmospheric particulate matter smaller than 2.5 μm (PM2.5) in the aqueous phase. PM2.5 was collected during a winter, a spring, and a summer campaign in urban and rural settings in Colorado and extracted into water. The aqueous extracts were photoirradiated using simulated sunlight, and the production rate (r•OH) and the effects of hydroxyl radicals (•OH) were measured as well as the optical properties as a function of the photoaging of the extracts. r•OH was seen to have a strong seasonality with low mean values for the winter and spring extracts (4.8 and 14 fM s-1 mgC-1 L, respectively) and a higher mean value for the summer extracts (65.4 fM s-1 mgC-1 L). For the winter extracts, •OH was seen to mostly originate from nitrate photolysis while for the summer extracts, a correlation was seen between r•OH and iron concentration. The extent of photobleaching of the extracts was correlated with r•OH, and the correlation also indicated that non-•OH processes took place. Using the •OH measurements and singlet oxygen (1O2) measurements, the half-life of a selection of compounds was modeled in the atmospheric aqueous phase to be between 1.9 and 434 h.
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Affiliation(s)
- Frank Leresche
- Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Joseph R Salazar
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - David J Pfotenhauer
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Michael P Hannigan
- Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Brian J Majestic
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Fernando L Rosario-Ortiz
- Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
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20
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Insights into the Time Evolution of Slowly Photodegrading Contaminants. Molecules 2021; 26:molecules26175223. [PMID: 34500658 PMCID: PMC8434510 DOI: 10.3390/molecules26175223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
Photochemical degradation plays an important role in the attenuation of many recalcitrant pollutants in surface freshwaters. Photoinduced transformation kinetics are strongly affected by environmental conditions, where sunlight irradiance plays the main role, followed by water depth and dissolved organic carbon (DOC). Apart from poorly predictable weather-related issues, fair-weather irradiance has a seasonal trend that results in the fastest photodegradation in June and the slowest in December (at least in temperate areas of the northern hemisphere). Pollutants that have first-order photochemical lifetimes longer than a week take more than one month to achieve 95% photodegradation. Consequently, they may experience quite different irradiance conditions as their photodegradation goes on. The relevant time trend can be approximated as a series of first-order kinetic tracts, each lasting for one month. The trend considerably departs from an overall exponential decay, if degradation takes long enough to encompass seasonally varying irradiance conditions. For instance, sunlight irradiance is higher in July than in April, but increasing irradiance after April and decreasing irradiance after July ensure that pollutants emitted in either month undergo degradation with very similar time trends in the first 3-4 months after emission. If photodegradation takes longer, pollutants emitted in July experience a considerable slowdown in photoreaction kinetics as winter is approached. Therefore, if pollutants are photostable enough that their photochemical time trend evolves over different seasons, degradation acquires some peculiar features than cannot be easily predicted from a mere analysis of lifetimes in the framework of simple first-order kinetics. Such features are here highlighted with a modelling approach, taking the case of carbamazepine as the main example. This contaminant is almost totally biorecalcitrant, and it is also quite resistant to photodegradation.
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21
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Partanen SB, Apell JN, Lin J, McNeill K. Factors affecting the mixed-layer concentrations of singlet oxygen in sunlit lakes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1130-1145. [PMID: 34231605 PMCID: PMC8372756 DOI: 10.1039/d1em00062d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 06/16/2021] [Indexed: 06/01/2023]
Abstract
The steady-state concentration of singlet oxygen within a lake ([1O2]SS) is an important parameter that can affect the environmental half-life of pollutants and environmental fate modelling. However, values of [1O2]SS are often determined for the near-surface of a lake, and these values typically do not represent the average over the epilimnia of lakes. In this work, the environmental and physical factors that have the largest impact on [1O2]SS within lake epilimnia were identified. It was found that the depth of the epilimnion has the largest impact on depth-averaged [1O2]SS, with a factor of 8.8 decrease in [1O2]SS when epilimnion depth increases from 2 m to 20 m. The next most important factors are the wavelength-dependent singlet oxygen quantum yield relationship and the latitude of the lake, causing variations in [1O2]SS by factors of 3.2 and 2.5 respectively, over ranges of representative values. For a set of representative parameters, the depth-averaged value of [1O2]SS within an average epilimnion depth of 9.0 m was found to be 5.8 × 10-16 M and the near-surface value of [1O2]SS was found to be 1.9 × 10-14 M. We recommend a range of 6 × 10-17 to 5 × 10-15 M as being more representative of [1O2]SS values within the epilimnia of lakes globally and potentially more useful for estimating pollutant lifetimes than those calculated using [1O2]SS values that correspond to near-surface, summer midday values. This work advances our understanding of [1O2]SS inter-lake variability in the environment, and provides estimates of [1O2]SS for practitioners and researchers to assess environmental half-lives of pollutants due to reaction with singlet oxygen.
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Affiliation(s)
- Sarah B. Partanen
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich8092 ZurichSwitzerland
| | - Jennifer N. Apell
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich8092 ZurichSwitzerland
- Department of Civil and Urban Engineering, New York University Tandon School of Engineering6 MetroTech CenterBrooklynNY 11201USA
| | - Jianming Lin
- Firmenich IncorporatedP.O. Box 5880PrincetonNew Jersey 08543USA
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich8092 ZurichSwitzerland
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22
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Schmitt M, Wack K, Glaser C, Wei R, Zwiener C. Separation of Photochemical and Non-Photochemical Diurnal In-Stream Attenuation of Micropollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8908-8917. [PMID: 34110816 DOI: 10.1021/acs.est.1c02116] [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: 05/06/2023]
Abstract
For a better process understanding of in-stream attenuation of trace organic contaminants (TrOCs), quantitative comparisons between field studies under different environmental conditions and controlled laboratory experiments are important to separate different processes. However, this is hampered by the challenge to transfer kinetics from the laboratory to different field conditions due to the lack of good quantitative measures to account for different boundary conditions. For phototransformation, in situ light conditions in a river are difficult to determine because light is reduced, for instance, by absorption, scattering on suspended particles, and shading effects. In this study, we present an approach to separate photochemical from non-photochemical diurnal in-stream attenuation based on rate constants relative to diclofenac, as a reference compound, to account for the difference in the in situ light conditions combined with laboratory experiments. 12 out of 45 detected target TrOCs showed a diurnal attenuation at a selected river stretch. A non-photochemical process, potentially biotransformation, was responsible for the diurnal attenuation of bisoprolol, metoprolol, O-desmethylvenlafaxine, tramadol, and venlafaxine. Attenuation of amisulpride, flufenamic acid, hydrochlorothiazide, naproxen, and xipamide can be quantitatively explained by phototransformation, partially for sotalol. Attenuation rate constants of hydrochlorothiazide at different field sites from this study and from published data range over 2 orders of magnitude. Differences can be quantitatively explained by different light exposures but not by water chemical parameters.
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Affiliation(s)
- Markus Schmitt
- Center for Applied Geoscience, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
| | - Katja Wack
- Center for Applied Geoscience, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
| | - Clarissa Glaser
- Center for Applied Geoscience, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
| | - Ran Wei
- Center for Applied Geoscience, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
| | - Christian Zwiener
- Center for Applied Geoscience, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany
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23
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Gruber K, Courteau B, Bokhoree M, McMahon E, Kotz J, Nienow A. Photolysis of the herbicide dicamba in aqueous solutions and on corn ( Zea mays) epicuticular waxes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:786-802. [PMID: 33988203 DOI: 10.1039/d1em00058f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Dicamba, 3,6-dichloro-2-methoxybenzoic acid, has been used in agriculture as an herbicide for over fifty years, and has seen an increase in use in the past decade due to the development of glyphosate resistant weeds and soybeans genetically modified to resist dicamba. Despite the previous use of dicamba, many questions remain regarding its environmental fate, especially the new commercial formulations used on genetically modified crops. Here, the photolysis of dicamba, including the commercial formulation Diablo®, is examined in aqueous solutions of varying water quality and on the surface of corn epicuticular waxes. Dicamba is stable to hydrolysis but degrades under UV light. The photolytic half-life for dicamba photolysis in aqueous solutions at pH 7 irradiated with Rayonet UVB lamps (280-340 nm) was t1/2 = 43.3 min (0.72 hours), in aqueous solutions at pH 7 in a Q-Sun solar simulator (λ > 300 nm) was t1/2 = 13.4 hours, and on epicuticular waxes irradiated in the Q-Sun solar simulator was t1/2 = 105 hours. Experiments with adjuvants, compounds added into the commercial formulations of dicamba, led to increases in rate constants for both aqueous and wax experiments. In addition to kinetic rate constants, photoproducts were tentatively assigned for the aqueous solution experiments. This work deepens the knowledge of the environmental fate of dicamba including the role surfactants play in chemical reactions and in providing new applications of current methods to examine the photolysis of chemicals sorbed to surfaces.
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Affiliation(s)
- Kaitlyn Gruber
- Gustavus Adolphus College, 800 W College Avenue, St Peter, Minnesota 56082, USA.
| | - Brittany Courteau
- Gustavus Adolphus College, 800 W College Avenue, St Peter, Minnesota 56082, USA.
| | - Maheemah Bokhoree
- Gustavus Adolphus College, 800 W College Avenue, St Peter, Minnesota 56082, USA.
| | - Elijah McMahon
- Gustavus Adolphus College, 800 W College Avenue, St Peter, Minnesota 56082, USA.
| | - Jenna Kotz
- Gustavus Adolphus College, 800 W College Avenue, St Peter, Minnesota 56082, USA.
| | - Amanda Nienow
- Gustavus Adolphus College, 800 W College Avenue, St Peter, Minnesota 56082, USA.
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24
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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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25
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Ossola R, Jönsson OM, Moor K, McNeill K. Singlet Oxygen Quantum Yields in Environmental Waters. Chem Rev 2021; 121:4100-4146. [PMID: 33683861 DOI: 10.1021/acs.chemrev.0c00781] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Singlet oxygen (1O2) is a reactive oxygen species produced in sunlit waters via energy transfer from the triplet states of natural sensitizers. There has been an increasing interest in measuring apparent 1O2 quantum yields (ΦΔ) of aquatic and atmospheric organic matter samples, driven in part by the fact that this parameter can be used for environmental fate modeling of organic contaminants and to advance our understanding of dissolved organic matter photophysics. However, the lack of reproducibility across research groups and publications remains a challenge that significantly limits the usability of literature data. In the first part of this review, we critically evaluate the experimental techniques that have been used to determine ΦΔ values of natural organic matter, we identify and quantify sources of errors that potentially explain the large variability in the literature, and we provide general experimental recommendations for future studies. In the second part, we provide a qualitative overview of known ΦΔ trends as a function of organic matter type, isolation and extraction procedures, bulk water chemistry parameters, molecular and spectroscopic organic matter features, chemical treatments, wavelength, season, and location. This review is supplemented with a comprehensive database of ΦΔ values of environmental samples.
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Affiliation(s)
- Rachele Ossola
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Oskar Martin Jönsson
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Kyle Moor
- Utah Water Research Laboratory, Department of Civil and Environmental Engineering, Utah State University, 84322 Logan, Utah, United States
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
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Cai Y, Apell JN, Pflug NC, McNeill K, Bollmann UE. Photochemical fate of medetomidine in coastal and marine environments. WATER RESEARCH 2021; 191:116791. [PMID: 33433334 DOI: 10.1016/j.watres.2020.116791] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
Medetomidine has been authorized in ship hull paints as an antifouling biocide under the biocidal product regulation in Europe since 2016. Its release into marine systems causes concerns over persistence and toxicity. However, the environmental fate of medetomidine has not been fully investigated. In this study, the photodegradation of medetomidine under natural sunlight conditions was investigated using collected coastal and sea waters. In addition, the phototransformation of medetomidine with reactive species (i.e., singlet oxygen, excited triplet state organic matter, and hydroxyl radicals) under UVA light was examined. Photoproducts were isolated by high-performance liquid chromatography (HPLC), identified by a combination of nuclear magnetic resonance (NMR) spectroscopy and time-of-flight mass spectrometry (qTOF), and reaction mechanisms were proposed. The results show that medetomidine is a neutral base (pKa of protonated form = 7.2) that leads to two different protonation states in the aquatic environment. Photodegradation of neutral medetomidine was dominated by reaction with singlet oxygen, while protonated medetomidine was relatively photostable. The contribution of reactive species to the overall photodegradation of neutral medetomidine was calculated to provide an assessment of phototransformation of medetomidine. The half-live of medetomidine was < 1.5 days in natural waters (pHcoastal = 8.3; pHsea = 8.1) under sunlit near-surface conditions, suggesting that it is not persistent in the aquatic environment. Because medetomidine has a relatively short half-life in sunlit aquatic ecosystems, a number of products, such as 2-(2,3-dimethylphenyl)propanamide, can be formed by photochemical reactions of medetomidine, with unknown consequences for marine and coastal waters.
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Affiliation(s)
- Yi Cai
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Jennifer N Apell
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland; Department of Civil and Urban Engineering, New York University Tandon School of Engineering, 6 Metrotech Center, Brooklyn, New York, 11201, USA
| | - Nicholas C Pflug
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland
| | - Kristopher McNeill
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland
| | - Ulla E Bollmann
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark; Geological Survey of Denmark and Greenland (GEUS), ØsterVoldgade 10, 1350 Copenhagen, Denmark.
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Vione D. The modelling of Surface-Water photoreactions made easier: introducing the concept of 'equivalent monochromatic wavelengths'. WATER RESEARCH 2021; 190:116675. [PMID: 33279749 DOI: 10.1016/j.watres.2020.116675] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
The recent development of successful model approaches that predict the photochemical behaviour of surface waters has greatly aided in the understanding of how water environments work and will likely work in the future, from a photochemical point of view. However, the inherent multi-wavelength (polychromatic) nature of environmental photochemistry causes the relevant mathematics to be quite complex, which discourages many scientists to carry out photochemical calculations. To greatly simplify model mathematics, this paper proposes a new approach that is based on a monochromatic approximation to the polychromatic problem, introducing the concept of what is here defined as equivalent monochromatic wavelengths (EMWs). The EMW is the single wavelength that reproduces the behaviour of the polychromatic system, using a monochromatic (Lambert-Beer based) equation. The EMW approach largely simplifies calculations, getting rid of integrals and allowing for much more straightforward and manageable equations to be obtained. In particular, this work shows that: (i) the EMW approach, although approximated, entails a negligible loss in accuracy compared to the exact polychromatic treatment of photochemical reactions; (ii) in the case of direct photolysis, the quantum yield is to be replaced by an apparent photon efficiency that is not bound to be < 1 (quantum yields can actually be > 1 for chain reactions and few other cases, but this is not the point here); (iii) the monochromatic Lambert-Beer equations work in most cases once the EMW is identified, with the present exception of sunlight absorption by chromophoric dissolved organic matter (CDOM). The latter spans a very wide wavelength range (from 300 to at least 600 nm), which makes a single-wavelength treatment more difficult. However, a relatively small modification to the monochromatic Lambert-Beer equation allows for successfully using the EMW approach, in the case of CDOM as well. The near-perfect coincidence between polychromatic and EMW-based predictions of photodegradation kinetics is here shown for the pollutants atrazine, bentazone, carbamazepine, diclofenac, diuron and ibuprofen. Extension to additional compounds requires translation of the traditional, polychromatic language into the EMW one. Hopefully, this contribution will introduce a new paradigm in the mathematical description of photochemical reactions in environmental waters. It could also become a new and simple way to treat multi-wavelength systems in general photochemistry studies, thereby completely changing the way multi-wavelength problems are dealt with.
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Affiliation(s)
- Davide Vione
- Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 5, 10125 Torino, Italy.
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Scholes RC, King JF, Mitch WA, Sedlak DL. Transformation of Trace Organic Contaminants from Reverse Osmosis Concentrate by Open-Water Unit-Process Wetlands with and without Ozone Pretreatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:16176-16185. [PMID: 33269915 DOI: 10.1021/acs.est.0c04406] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Reverse osmosis (RO) treatment of municipal wastewater effluent is becoming more common as water reuse is implemented in water-stressed regions. Where RO concentrate is discharged with limited dilution, concentrations of trace organic contaminants could pose risks to aquatic ecosystems. To provide a low-cost option for removing trace organic compounds from RO concentrate, a pilot-scale treatment system comprising open-water unit-process wetlands with and without ozone pretreatment was studied over a 2-year period. A suite of ecotoxicologically relevant organic contaminants was partially removed via photo- and bio-transformations, including β-adrenergic blockers, antivirals, antibiotics, and pesticides. Biotransformation rates were as fast as or up to approximately 50% faster than model predictions based upon data from open-water wetlands that treated municipal wastewater effluent. Phototransformation rates were comparable to or as much as 60% slower than those predicted by models that accounted for light penetration and scavenging of reactive oxygen species. Several compounds were transformed during ozone pretreatment that were poorly removed in the open-water wetland. The combined treatment system resulted in a decrease in the risk quotients of trace organic contaminants in the RO concentrate, but still dilution may be required to protect sensitive species from urban-use pesticides with low environmental effect concentrations.
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Affiliation(s)
- Rachel C Scholes
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
- NSF Engineering Research Center for Reinventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305, United States
| | - Jacob F King
- NSF Engineering Research Center for Reinventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305, United States
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
| | - William A Mitch
- NSF Engineering Research Center for Reinventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305, United States
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
| | - David L Sedlak
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
- NSF Engineering Research Center for Reinventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305, United States
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Apell JN, Kliegman S, Solá-Gutiérrez C, McNeill K. Linking Triclosan's Structural Features to Its Environmental Fate and Photoproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14432-14441. [PMID: 33156610 DOI: 10.1021/acs.est.0c05121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Triclosan is a high-production volume chemical, which has become widely detected in environmental systems because of its widespread usage. Photodegradation has been identified as a major degradation pathway, but the identified photoproducts are also chemicals of concern. In this study, lower chlorinated derivatives of triclosan were synthesized to investigate the impact the chlorine substituents have on the photodegradation rate and the photoproducts produced. In addition, the photodegradation of two classes of photoproducts-dibenzo-p-dioxins (DDs) and 2,2'-dihydroxylated biphenyls-was also investigated. Degradation of triclosan in near-surface sunlit waters was relatively fast (t1/2 < 5 h). Calculated degradation rates were slower for DDs and faster for dihydroxylated biphenyls in comparison to that for triclosan. In addition, the 2'-Cl substituent was critical for the high quantum yield measured for triclosan and necessary for the photodegradation mechanism that forms DDs and dihydroxylated biphenyls. The 4-Cl substituent was responsible for higher rates of light absorption and the environmentally relevant pKa. Without either of these substituents, the environmental fate of triclosan would be markedly different.
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Affiliation(s)
- Jennifer N Apell
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland
- Department of Civil and Urban Engineering, New York University Tandon School of Engineering, 6 MetroTech Center, Brooklyn, New York 11201, United States
| | - Sarah Kliegman
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland
| | - Claudia Solá-Gutiérrez
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland
| | - Kristopher McNeill
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland
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Song YK, Hong SH, Eo S, Han GM, Shim WJ. Rapid Production of Micro- and Nanoplastics by Fragmentation of Expanded Polystyrene Exposed to Sunlight. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11191-11200. [PMID: 32786551 DOI: 10.1021/acs.est.0c02288] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Expanded polystyrene (EPS) is a common plastic marine debris found in oceans worldwide. The unique "foamed" structure of EPS, which is composed of thin layers, is more vulnerable to fragmentation than bulk plastics. However, the production rate of micro- and nanoplastics by the fragmentation of EPS following sunlight exposure remains largely unknown. Here, we determined the fragmentation rate and weight loss of EPS in an outdoor weathering experiment that ran for 24 months. It took only 1 month for the weight of an EPS box to decline by 5% due to photodegradation, and approximately 6.7 × 107 micro- and nanoparticles/cm2 could be produced at a latitude of 34 °N. These results indicate that macro EPS debris can continually produce a massive number of particles within a relatively short exposure duration. The findings provide useful information to inform policymakers how rapidly to remove "likely fragmented" plastic litter from the environment.
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Affiliation(s)
- Young Kyoung Song
- Korea Institute of Ocean Science and Technology, Geoje-shi 53201, South Korea
| | - Sang Hee Hong
- Korea Institute of Ocean Science and Technology, Geoje-shi 53201, South Korea
- University of Science and Technology, Daejeon 34113, South Korea
| | - Soeun Eo
- Korea Institute of Ocean Science and Technology, Geoje-shi 53201, South Korea
- University of Science and Technology, Daejeon 34113, South Korea
| | - Gi Myung Han
- Korea Institute of Ocean Science and Technology, Geoje-shi 53201, South Korea
| | - Won Joon Shim
- Korea Institute of Ocean Science and Technology, Geoje-shi 53201, South Korea
- University of Science and Technology, Daejeon 34113, South Korea
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Partanen SB, Erickson PR, Latch DE, Moor KJ, McNeill K. Dissolved Organic Matter Singlet Oxygen Quantum Yields: Evaluation Using Time-Resolved Singlet Oxygen Phosphorescence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3316-3324. [PMID: 32064862 DOI: 10.1021/acs.est.9b07246] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Singlet oxygen (1O2) generation quantum yields from chromophoric dissolved organic matter (CDOM) have been reported for many samples over the past 4 decades. Yet even for standardized isolates such as those from the International Humic Substance Society (IHSS), wide-ranging values exist in the literature. In this manuscript, time-resolved 1O2 phosphorescence was used to determine the 1O2 quantum yields (ΦΔ) of a variety of dissolved organic matter (DOM) isolates and natural waters. In general, the 1O2 quantum yield values in this study are in the middle, although below the median of the range of past reported values (e.g., for Suwannee River Natural Organic Matter IHSS isolate: 1.8% vs 0.23-2.89%). Notably, hydrophobic neutral fractions of DOM isolates were found to possess the highest 1O2 quantum yields, an interesting result given that these fractions are not retained in typical humic and fulvic acid isolation procedures that use XAD resins. The excitation wavelength dependence of 1O2 generation from CDOM was also examined, and an approximate linear decrease with longer excitation wavelength was observed. This work advances the understanding of CDOM photoprocesses, especially in relation to wavelength-dependent 1O2 production, which is valuable for assessing real-world environmental behavior.
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Affiliation(s)
- Sarah B Partanen
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Paul R Erickson
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Douglas E Latch
- Department of Chemistry, Seattle University, Seattle, Washington 98122, United States
| | - Kyle J Moor
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
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Apell JN, Pflug NC, McNeill K. Photodegradation of Fludioxonil and Other Pyrroles: The Importance of Indirect Photodegradation for Understanding Environmental Fate and Photoproduct Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11240-11250. [PMID: 31486641 DOI: 10.1021/acs.est.9b03948] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Fludioxonil is a pyrrole-containing pesticide whose registration as a plant protection product is currently under review in the United States and Europe. There are concerns over its potential persistence and toxicity in the aquatic environment; however, the pyrrole moiety represents a potential reaction site for indirect photodegradation. In this study, the direct and indirect photodegradation of fludioxonil, along with pyrrole, 3-cyanopyrrole, and 3-phenylpyrrole, were investigated. Results showed that pyrrole moieties are capable of undergoing direct photoionization and sensitized photooxidation to form radical cation species, which then likely deprotonate and react with dissolved oxygen. Additionally, pyrrole moieties can undergo reactions with singlet oxygen (1O2). Furthermore, the presence of electron-withdrawing or -donating substituents substantially impacted the reaction rate with 1O2 as well as the one-electron oxidation potential of the pyrrole that dictates reactions with triplet states of dissolved organic matter (3CDOM*). For fludioxonil, which can undergo both direct and indirect photodegradation, the reaction rate constant with 1O2 alone resulted in a predicted t1/2 < 2 days in waters under sunlit near-surface conditions, suggesting it will not be persistent in aquatic systems. These results are useful for evaluating the environmental fate of fludioxonil as well as other pyrrole compounds.
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Affiliation(s)
- Jennifer N Apell
- Institute for Biogeochemistry and Pollutant Dynamics , ETH Zurich , Universitaetstrasse 16 , 8092 Zurich , Switzerland
| | - Nicholas C Pflug
- Institute for Biogeochemistry and Pollutant Dynamics , ETH Zurich , Universitaetstrasse 16 , 8092 Zurich , Switzerland
| | - Kristopher McNeill
- Institute for Biogeochemistry and Pollutant Dynamics , ETH Zurich , Universitaetstrasse 16 , 8092 Zurich , Switzerland
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