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Li W, Wang B, Liu N, Shi X, Yang M, Liu CQ. Microbial regulation on refractory dissolved organic matter in inland waters. WATER RESEARCH 2024; 262:122100. [PMID: 39042969 DOI: 10.1016/j.watres.2024.122100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 07/10/2024] [Accepted: 07/13/2024] [Indexed: 07/25/2024]
Abstract
The production of refractory dissolved organic matter (RDOM) is complex and closely related to microbial consortia in aquatic ecosystems; however, it is still unclear how microorganisms regulate the production of RDOM and its molecular composition in inland waters. Therefore, we conducted a large-scale survey of inland waters and analyzed the optical and mass spectrometric characteristics of DOM, the microbial community and functional genes, as well as related environmental parameters, to understand the abovementioned issues. Here, the RDOM production was found mainly regulated by microbial (e.g., phylogeny and community assembly) rather than other environmental factors in inland waters. Biostatistical analyses and carbon isotopic evidence indicated that the successive microbial processing from labile DOM to RDOM (i.e., carboxyl-rich alicyclic molecules, CRAMs) was widely present in inland waters, involving the microbially mediated carbon skeleton turnover and heteroatom conversion. There was a significant empirical relationship between CRAMs and the ratio of Proteobacteria to Actinobacteria, highlighting the intraspecific interaction of bacteria more important than other microbial groups (i.e., archaea, eukaryotes, and fungi) for the RDOM production. This study demonstrated a fundamental role of microbial regulation in RDOM production within the inland waters, thereby facilitating future estimation of carbon sequestration potential in inland aquatic ecosystems.
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Affiliation(s)
- Wanzhu Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Baoli Wang
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China; Tianjin Bohai Rim Coastal Earth Critical Zone National Observation and Research Station, Tianjin, 300072, China.
| | - Na Liu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Xinjie Shi
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Meiling Yang
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Cong-Qiang Liu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China; Tianjin Bohai Rim Coastal Earth Critical Zone National Observation and Research Station, Tianjin, 300072, China
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2
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Wei Z, Li N, Zhang X, Zheng L, Mo S, Korshin G, Li Q, Yan M. Characterizing photochemical production carboxyl content of dissolved organic matters using absorbance spectroscopy combined with FT-ICR MS. CHEMOSPHERE 2023; 344:140352. [PMID: 37806326 DOI: 10.1016/j.chemosphere.2023.140352] [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: 06/16/2023] [Revised: 08/27/2023] [Accepted: 10/02/2023] [Indexed: 10/10/2023]
Abstract
Irradiation can significantly impact the structure, reactivity and environmental behavior of dissolved organic matter (DOM). The extent of these processes remains to be ascertained in more detail but the heterogeneity and site-specificity of DOM, and the lack of methods to characterize DOM at its environmentally-relevant concentrations make it a challenge. In this study, the differences of DOM response to photodegradation in four typical origins (i.e., surface water, sediment and intracellular and extracellular algal DOM) were tracked on the molecular-level using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Changes of the carboxyl and phenolic DOM moieties induced by irradiation were quantified by spectroscopic titrations, and the mechanism of functional groups affecting the changes of specific molecular composition was qualitatively proposed. The results demonstrated that intracellular algal organic matter (I-DOM) was most susceptible to photodegradation (ca. 63% DOM loss), then came extracellular algal organic matter (E-DOM) and surface water DOM (W-DOM) (ca. 15% DOM loss). Sediment DOM (S-DOM) was most resistant to irradiation, with a very small level of its mineralization. Lipids, lignin-like compounds and tannin-like compounds in I-DOM and E-DOM were relatively photo-labile. The photodegradation of lipids was related to the decarboxylation of carboxyl functional groups, while the photodegradation of tannin-like compounds was related to the rupture of phenolic functional groups. In comparison, the molecular composition of W-DOM and S-DOM was less affected by irradiation, which was also reflected in the fact that the carboxyl and phenolic functional groups were highly photo-resistant. This study showed that the photoactivity of DOM in surface water was closely related to the abundance of algae, so controlling the excessive reproduction of algae may have a positive effect on stability of quality and quantity of organic matter in surface water.
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Affiliation(s)
- Zizhuo Wei
- College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, Liaoning, China; Qinhuangdao key Laboratory of Water-saving Pollution Control and Ecological Restoration, College of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004, Hebei, China
| | - Na Li
- College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, Liaoning, China; Qinhuangdao key Laboratory of Water-saving Pollution Control and Ecological Restoration, College of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004, Hebei, China
| | - Xinyi Zhang
- College of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102208, China
| | - Lei Zheng
- College of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102208, China
| | - Shansheng Mo
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Gregory Korshin
- Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195-2700, United States
| | - Qingwei Li
- College of Resources and Civil Engineering, Northeastern University, Shenyang, 110819, Liaoning, China; Qinhuangdao key Laboratory of Water-saving Pollution Control and Ecological Restoration, College of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao, 066004, Hebei, China
| | - Mingquan Yan
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China.
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An Y, Ma XY, Chen W, Li W, Yang S, Chen R, Wang XC. The impact of inorganic ions on the solar photolysis of chlorinated dissolved organic matter from different sources: Spectral characteristics, disinfection byproducts, and biotoxicities. JOURNAL OF HAZARDOUS MATERIALS 2023; 451:131135. [PMID: 36889069 DOI: 10.1016/j.jhazmat.2023.131135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/02/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Dissolved organic matter (DOM) from wastewater treatment plant (WWTP) effluent is chlorinated and then discharged into natural waters, where it is subject to solar irradiation. However, the impacts of inorganic ions in natural waters on the photochemical transformations of the chlorinated DOM (DOM-Cl) have not been studied comprehensively. In this study, variations in the spectral characteristics, disinfection byproducts (DBPs), and biotoxicities of DOM-Cl under solar irradiation at different pH values and in the presence of NO3- and HCO3- were revealed. Three sources of DOM, including DOM from a WWTP effluent, natural organic matter from the Suwannee River, and DOM from plant leaf leachate, were investigated. Solar irradiation resulted in the oxidation of the highly reactive aromatic structures and then reduced the amounts of chromophoric and fluorescent DOM, especially under alkaline conditions. Moreover, alkaline conditions significantly promoted the detected DBPs degradation and the biotoxicities attenuation, while NO3- and HCO3- generally impeded them (or did not work). Dehalogenation of the unknown halogenated DBPs and photolysis of the nonhalogenated organics were the main mechanisms for the DOM-Cl biotoxicity reductions. Hence, improving the ecological safety of WWTP effluents could be achieved through solar irradiation by removing the DBPs formed.
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Affiliation(s)
- Yali An
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Xiaoyan Y Ma
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
| | - Wenfeng Chen
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Wei Li
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Siyan Yang
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Rong Chen
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Xiaochang C Wang
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
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4
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Slavik I, Kostrowski D, Uhl W. Effect of solar radiation on natural organic matter composition in surface waters and resulting impacts on drinking water treatment. ENVIRONMENTAL TECHNOLOGY 2023; 44:1549-1565. [PMID: 34839798 DOI: 10.1080/09593330.2021.2007289] [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] [Received: 09/18/2021] [Accepted: 11/07/2021] [Indexed: 06/13/2023]
Abstract
Solar radiation experiments showed a shift in the composition of natural organic matter (NOM). Due to irradiation, the concentration of high molecular weight (HMW) molecules decreased, and that of the low molecular weight (LMW) fraction increased. Microbiological analyses showed that biodegradation was neglectable. To assess the consequences for water treatment processes, coagulation jar tests were performed by comparing the removal effectivity for NOM fractions from irradiated and unirradiated raw water. The degree of dissolved organic carbon (DOC) removal by coagulation was lower for irradiated waters. As primarily HMW organic compounds are removed by coagulation, the decrease in coagulation performance is attributed to the increase in the LMW concentration due to photochemical reactions induced by solar radiation. Flocs were about 15% larger for irradiated water. Possibilities to adapt water treatment to respond to changes in DOC composition and concentration are outlined. Ozonation-biofiltration is judged as the most promising treatment process to cope with climate change-related challenges in drinking water treatment.
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Affiliation(s)
- I Slavik
- Hydro-Ingenieure GmbH, Düsseldorf, Germany
- Hochschule Magdeburg-Stendal, FB Wasser, Umwelt, Bau und Sicherheit Magdeburg, Germany
- Water Supply Engineering, Technische Universität Dresden, Dresden, Germany
| | - D Kostrowski
- Water Supply Engineering, Technische Universität Dresden, Dresden, Germany
| | - W Uhl
- Water Supply Engineering, Technische Universität Dresden, Dresden, Germany
- Aquateam COWI AS, Oslo, Norway
- Department of Civil and Environmental Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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5
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Pittaway P, Scobie M, Schmidt E. Evaporative loss and environmental impact of covers on water storages: A review. JOURNAL OF ENVIRONMENTAL QUALITY 2023; 52:241-257. [PMID: 36715076 DOI: 10.1002/jeq2.20454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Commercial products to reduce evaporation from water storages have been developed since the 1960s. Categorised as suspended and floating continuous covers, floating modular covers, and monomolecular (monolayer) and multimolecular chemical films, product adoption by agricultural water managers is low. The role of evaporation reduction in improving water use efficiency is well established, but information on the suitability of product categories for farm water storages is lacking. We reviewed the environmental and operational performance of commercial evaporation reduction products using published and supplier information on design, mode of action, installation, operation, maintenance, the evaporation reduction achieved, and the impact on water quality, to analyze the suitability of the five product classes for water storages ranging in size from ≤2 to 100 ha. Span loading, cable tensioning and anchorage limit continuous covers to storages ≤2 ha. The cover fabric must reduce light transmittance by 80%, to reduce evaporation by 71%. Ballasting, tethering, and removal during dry times limit the use of continuous floating covers to storages ≤2 ha, managed close to full capacity. Floating modules must cover 88% of the surface to reduce evaporation by 70%, limiting their use to storages of ≤5 ha. Monolayer application is more flexible, but smart product selection and automated application strategies are required to improve performance. The number of application sites required to achieve full surface coverage limits monolayer use to storages ≤100 ha. Higher rates of application and poor self-spreading may limit multimolecular films to storages ≤10 ha.
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Affiliation(s)
- Pamela Pittaway
- Centre for Agricultural Engineering, University of Southern Queensland, Toowoomba, Australia
| | - Michael Scobie
- Centre for Agricultural Engineering, University of Southern Queensland, Toowoomba, Australia
| | - Erik Schmidt
- Centre for Agricultural Engineering, University of Southern Queensland, Toowoomba, Australia
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6
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Ossola R, Gruseck R, Houska J, Manfrin A, Vallieres M, McNeill K. Photochemical Production of Carbon Monoxide from Dissolved Organic Matter: Role of Lignin Methoxyarene Functional Groups. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13449-13460. [PMID: 36054115 PMCID: PMC9494748 DOI: 10.1021/acs.est.2c03762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/18/2022] [Accepted: 08/18/2022] [Indexed: 05/25/2023]
Abstract
Carbon monoxide (CO) is the second most abundant identified product of dissolved organic matter (DOM) photodegradation after CO2, but its formation mechanism remains unknown. Previous work showed that aqueous photodegradation of methoxy-substituted aromatics (ArOCH3) produces CO considerably more efficiently than aromatic carbonyls. Following on this precedent, we propose that the methoxy aromatic groups of lignin act as the C source for the photochemical formation of CO from terrestrial DOM via a two-step pathway: formal hydrolytic demethylation to methanol and methanol oxidation to CO. To test the reasonableness of this mechanism, we investigated the photochemistry of eight lignin model compounds. We first observed that initial CO production rates are positively correlated with initial substrate degradation rates only for models containing at least one ArOCH3 group, regardless of other structural features. We then confirmed that all ArOCH3-containing substrates undergo formal hydrolytic demethylation by detecting methanol and the corresponding phenolic transformation products. Finally, we showed that hydroxyl radicals, likely oxidants to initiate methanol oxidation to CO, form during irradiation of all models. This work proposes an explicit mechanism linking ubiquitous, abundant, and easily quantifiable DOM functionalities to CO photoproduction. Our results further hint that methanol may be an abundant (yet overlooked) DOM photoproduct and a likely precursor of formaldehyde, formic acid, and CO2 and that lignin photodegradation may represent a source of hydroxyl radicals.
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Affiliation(s)
- Rachele Ossola
- Department
of Environmental Systems Science, ETH Zurich, Zurich 8092, Switzerland
| | - Richard Gruseck
- Department
of Environmental Systems Science, ETH Zurich, Zurich 8092, Switzerland
| | - Joanna Houska
- Eawag
Swiss Federal Institute of Aquatic Science and Technology, Dübendorf 8600, Switzerland
- School
of Architecture, Civil, and Environmental Engineering, École Polytechnique Fédérale
de Lausanne, Lausanne 1015, Switzerland
| | - Alessandro Manfrin
- Department
of Environmental Systems Science, ETH Zurich, Zurich 8092, Switzerland
| | - Morgan Vallieres
- Department
of Environmental Systems Science, ETH Zurich, Zurich 8092, Switzerland
| | - Kristopher McNeill
- Department
of Environmental Systems Science, ETH Zurich, Zurich 8092, Switzerland
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Saleh R, Andiane Hidayat S, Taufik A, Yin S. Removal of multiple pollutants from water using noble Ag/Au/magnetite/graphene/H2O2 system under light and ultrasound irradiation. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.103881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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8
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Linnik PN, Zhezherya VA, Linnik RP. Potential Transformations of Dissolved Organic Substances and Their Complexes with Metals in Surface Waters under Solar Radiation. RUSS J GEN CHEM+ 2022. [DOI: 10.1134/s1070363221130223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Wasswa J, Driscoll CT, Zeng T. Contrasting Impacts of Photochemical and Microbial Processing on the Photoreactivity of Dissolved Organic Matter in an Adirondack Lake Watershed. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1688-1701. [PMID: 35041388 PMCID: PMC8812123 DOI: 10.1021/acs.est.1c06047] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Photochemical and microbial processing are the prevailing mechanisms that shape the composition and reactivity of dissolved organic matter (DOM); however, prior research has not comparatively evaluated the impacts of these processes on the photoproduction of reactive intermediates (RIs) from freshly sourced terrestrial DOM. We performed controlled irradiation and incubation experiments with leaf and soil samples collected from an acid-impacted lake watershed in the Adirondack Mountain region of New York to examine the effects of DOM processing on the apparent quantum yields of RIs (Φapp,RI), including excited triplet states of DOM (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH). Photodegradation led to net reductions in Φapp,1O2, Φapp,3DOM*, and Φapp,•OH, whereas (photo-)biodegradation resulted in increases in Φapp,1O2 and Φapp,3DOM*. Photodegradation and (photo-)biodegradation also shifted the energy distribution of 3DOM* in different directions. Multivariate statistical analyses revealed the potential relevance of photo-biodegradation in driving changes in Φapp,1O2 and Φapp,3DOM* and prioritized five bulk DOM optical and redox properties that best explained the variations in Φapp,1O2 and Φapp,3DOM* along the watershed terrestrial-aquatic continuum. Our findings highlight the contrasting impacts of photochemical and microbial processes on the photoreactivity of freshly sourced terrestrial DOM and invite further studies to develop a more holistic understanding of their implications for aquatic photochemistry.
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Zhang Z, Zhao W, Hu W, Deng J, Ren L, Wu L, Chen S, Meng J, Pavuluri CM, Sun Y, Wang Z, Kawamura K, Fu P. Molecular characterization and spatial distribution of dicarboxylic acids and related compounds in fresh snow in China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 291:118114. [PMID: 34536649 DOI: 10.1016/j.envpol.2021.118114] [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: 06/15/2021] [Revised: 08/29/2021] [Accepted: 09/03/2021] [Indexed: 06/13/2023]
Abstract
Low molecular weight organic compounds are ubiquitous in the atmosphere. However, knowledge on their concentrations and molecular distribution in fresh snow remains limited. Here, twelve fresh snow samples collected at eight sites in China were investigated for dicarboxylic acids and related compounds (DCRCs) including oxocarboxylic acids and α-dicarbonyls. Dissolved organic carbon (DOC) concentrations in the snow samples ranged from 0.99 to 14.6 mg C L-1. Concentrations of total dicarboxylic acids were from 225 to 1970 μg L-1 (av. 650 μg L-1), while oxoacids (28.3-173, av. 68.1 μg L-1) and dicarbonyls (12.6-69.2, av. 31.3 μg L-1) were less abundant, accounting for 4.6-8.5% (6.2%), 0.45-1.4% (0.73%), and 0.12-0.88% (0.46%) of DOC, respectively. Molecular patterns of dicarboxylic acids are characterized by a predominance of oxalic acid (C2) (95.0-1030, av. 310 μg L-1), followed by phthalic (Ph) (9.69-244, av. 69.9 μg L-1) or succinic (C4) (23.8-163, av. 63.7 μg L-1) acid. Higher concentrations of Ph in snow from Beijing and Tianjin than other urban and rural regions suggest significant emissions from vehicular exhausts and other fossil fuel combustion sources in megacities. C2 constituted 40-54% of total diacids, corresponding to 1.5-2.6% of snow DOC. The total measured DCRCs represent 5.5-10% of snow DOC, which suggests that there are large amounts of unknown organics requiring further investigations. The spatial distributions of diacids exhibited higher loadings in megacities than rural and island sites. Molecular distributions of diacids indicated that the photochemical modification was restrained under the weak solar radiation during the snow events, while anthropogenic primary sources had a more significant influence in megacities than rural areas and islands.
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Affiliation(s)
- Zhimin Zhang
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Wanyu Zhao
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Wei Hu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Junjun Deng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Lujie Ren
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Libin Wu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Shuang Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Jingjing Meng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China; School of Geography and the Environment, Liaocheng University, Liaocheng, 252000, China
| | - Chandra Mouli Pavuluri
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Zifa Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Kimitaka Kawamura
- Chubu Institute for Advanced Studies, Chubu University, Kasugai, 487-8501, Japan
| | - Pingqing Fu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China.
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11
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Palma D, Khaled A, Sleiman M, Voyard G, Richard C. Effect of UVC pre-irradiation on the Suwannee river Natural Organic Matter (SRNOM) photooxidant properties. WATER RESEARCH 2021; 202:117395. [PMID: 34273776 DOI: 10.1016/j.watres.2021.117395] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
The present study aimed to investigate the changes in the chemical composition, and in the optical and photooxidant properties of Suwannee River Natural Organic Matter (SRNOM) induced by UVC (254 nm) treatment. The extent of the photodegradation was first assessed by UV-visible/fluorescence spectroscopies and organic carbon analysis. An in-depth investigation of the chemical changes was also conducted using liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry after derivatizations. A series of mono, di and tricarbonyls and mono and dicarboxylic acids in C1C6 were identified in samples irradiated from 1 to 4 h. After 3 h of irradiation, carbonyls accounted for 46% of the organic carbon remaining in solution whereas carboxylic acids represented about 2%. Then, we investigated the modifications of the photooxidant properties of SRNOM induced by these chemical changes. At 254 nm, UVC pre-irradiated SRNOM photodegraded glyphosate 29 times faster than original SRNOM and the reaction was fully inhibited by 2-propanol (5 × 10-3 M). This enhanced photooxidant properties at 254 nm toward glyphosate was therefore reasonably due to •OH radicals formation, as confirmed by additional ESR measurements. A mechanism involving a chain reaction was proposed based on independent experiments conducted on carbonyl compounds, particularly pyruvic acid and acetone. The findings of this study show that UVC pre-treatment of NOM can enhance the removal of water pollutants and suggests a possible integration of a NOM pre-activation step in engineered water treatment sytems.
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Affiliation(s)
- Davide Palma
- Université Clermont Auvergne, CNRS, SIGMA-Clermont, ICCF, F-63000 Clermont-Ferrand, France
| | - Amina Khaled
- Université Clermont Auvergne, CNRS, SIGMA-Clermont, ICCF, F-63000 Clermont-Ferrand, France
| | - Mohamad Sleiman
- Université Clermont Auvergne, CNRS, SIGMA-Clermont, ICCF, F-63000 Clermont-Ferrand, France
| | - Guillaume Voyard
- Université Clermont Auvergne, CNRS, SIGMA-Clermont, ICCF, F-63000 Clermont-Ferrand, France
| | - Claire Richard
- Université Clermont Auvergne, CNRS, SIGMA-Clermont, ICCF, F-63000 Clermont-Ferrand, France.
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12
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Xiao K, Abbt-Braun G, Horn H. Changes in the characteristics of dissolved organic matter during sludge treatment: A critical review. WATER RESEARCH 2020; 187:116441. [PMID: 33022515 DOI: 10.1016/j.watres.2020.116441] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/16/2020] [Accepted: 09/19/2020] [Indexed: 06/11/2023]
Abstract
Dissolved organic matter (DOM) of sludge is a heterogeneous mixture of high to low molecular weight organic substances which is including proteinaceous compounds, carbohydrates, humic substances, lipids, lignins, organic acids, organic micropollutants and other biological derived substances generated during wastewater treatment. This paper reviews definition, composition, quantification, and transformation of DOM during different sludge treatments, and the complex interplay of DOM with microbial communities. In anaerobic digestion, anaerobic digestion-refractory organic matter, particularly compounds showing polycyclic steroid-like, alkane and aromatic structures can be generated after pretreatment. During dewatering, the DOM fraction of low molecular weight proteins (< 20,000 Dalton) is the key parameter deteriorating sludge dewaterability. During composting, decomposition and polymerization of DOM occur, followed by the formation of humic substances. During landfill treatment, the composition of DOM, particularly humic substances, are related with leachate quality. Finally, suggestions are proposed for a better understanding of the transformation and degradation of DOM during sludge treatment. Future work in sludge studies needs the establishment and implementation of definitions for sample handling and the standardization of DOM methods for analysis, including sample preparation and fractionation, and data integration. A more detailed knowledge of DOM in sludge facilitates the operation and optimization of sludge treatment technologies.
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Affiliation(s)
- Keke Xiao
- School of Environmental Science & Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, Hubei 430074, China; Engler-Bunte-Institut, Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany; DVGW Research Laboratories, Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany
| | - Gudrun Abbt-Braun
- Engler-Bunte-Institut, Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany
| | - Harald Horn
- Engler-Bunte-Institut, Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany; DVGW Research Laboratories, Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany.
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13
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Wasswa J, Driscoll CT, Zeng T. Photochemical Characterization of Surface Waters from Lakes in the Adirondack Region of New York. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10654-10667. [PMID: 32786602 DOI: 10.1021/acs.est.0c02811] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The Adirondack Mountain region of New York, a historical hotspot for atmospheric sulfur and nitrogen deposition, features abundant lakes that are experiencing browning associated with recovery from acidification. Yet, much remains unknown about the photoreactivity of Adirondack lake waters. We quantified the apparent quantum yields (Φapp,RI) of photochemically produced reactive intermediates (RIs), such as excited triplet states of dissolved organic matter (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH), for surface waters collected from 16 representative Adirondack lakes. Φapp,3DOM* and Φapp,1O2 for native Adirondack lake waters fell within ranges reported for whole waters and DOM isolates from various sources, while Φapp,•OH were substantially lower than those measured for other aquatic samples. Orthogonal partial least squares and multiple linear regression analyses identified the spectral slope coefficient from 290 to 400 nm (S290-400) as the most effective predictor of Φapp,RI among measured water chemistry parameters and bulk DOM properties. Φapp,RI also exhibited divergent responses to controlled pH adjustment and aluminum or iron addition simulating hypothetical scenarios relevant to past and future water chemistry conditions of Adirondack lakes. This study highlights the need for continued research on changes in photoreactivity of acid-impacted aquatic ecosystems in response to browning and subsequent impacts on photochemical processes.
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Affiliation(s)
- Joseph Wasswa
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| | - Teng Zeng
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
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Liang H, Lyu LN, Sun C, Ding H, Wurgaft E, Yang GP. Low-molecular-weight organic acids as important factors impacting seawater acidification: A case study in the Jiaozhou Bay, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 727:138458. [PMID: 32339827 DOI: 10.1016/j.scitotenv.2020.138458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/31/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Low-molecular-weight organic acids (LMWOAs) are ubiquitous water-soluble organic compounds with mass production worldwide, but their influence on coastal marine environments is still lack of consideration. In this study, we select a typical nearshore bay - the Jiaozhou Bay, which is surrounded by Qingdao - a city with modern manufacture, agriculture, aquaculture and service industry, as study area, to investigate the effect of LMWOAs on the nearshore marine environment, and their impact on seawater acidification in coastal areas. During Sep. 2016 to Aug. 2017, we identified three different LMWOAs - acetic acid (AA), formic acid (FA) and lactic acid (LA), with average concentrations of 46.7, 13.9 and 1.4 μmol·L-1 in the seawater of the bay, respectively. Due to the establishment of the Jiaozhou Bay Bridge, the seawater exchange capacity was weakened and thereby the concentration and stocks of AA and FA increased. As weak acids in seawater, the influence of LMWOAs on the seawater acidification of the Jiaozhou Bay was investigated. LMWOAs had significant impact on seawater pH and every 10 μmol·L-1 LMWOA caused an average of 0.02 pH unit decrease. From 2010 to 2017, pH value in the seawater of the bay decreased by about 0.103 and LMWOAs contributed about 83% of its decrease. Besides, two models were established to estimate the influence of LMWOAs on the seawater pH by applying the data set of dissolved inorganic carbon (DIC), total alkalinity (TA) and LMWOAs. The results showed that LMWOAs could enhance acidification of coastal seawater. Considering the importance of LMWOAs in seawater, it is necessary to evaluate their future changes in coastal marine environments. This study initiated a way to identify the source of LMWOAs in seawater and to evaluate their contribution to seawater acidification, and also provided a series of dataset for future study on LMWOAs in coastal environment.
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Affiliation(s)
- Haorui Liang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Li-Na Lyu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Chengjun Sun
- Marine Ecology Center, First Institute of Oceanography, Ministry of Natural Resource, Qingdao 266061, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Haibing Ding
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory of Marine Science and Technology, Qingdao 266023, China; Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, Qingdao 266100, China.
| | - Eyal Wurgaft
- Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole 02543, USA
| | - Gui-Peng Yang
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory of Marine Science and Technology, Qingdao 266023, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China; Qingdao Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, Qingdao 266100, China.
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15
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Hong J, Liu L, Tan W, Qiu G. Arsenic release from arsenopyrite oxidative dissolution in the presence of citrate under UV irradiation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 726:138429. [PMID: 32305755 DOI: 10.1016/j.scitotenv.2020.138429] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Arsenopyrite oxidative dissolution is one of the most important sources of arsenic (As) pollution in the soils and waters around sulfide mining areas. Sunlight and low-molecular-weight organic acids in the environment affect the redox behavior of sulfide minerals. In this work, the As release from arsenopyrite was studied in the presence of citrate under UV irradiation, and the effects of dissolved oxygen and citrate concentrations and pH on As release rate were also investigated. The results indicated that As release from the oxidative dissolution of arsenopyrite is affected by the complexation between citrate and dissolved iron ions. Under dark conditions in air atmosphere, dissolved oxygen, Fe(III)-citrate and the active intermediate product O2- facilitated the release of As at pH 7.0, and the As release rate increased first and then decreased with increasing pH from 5.0 to 9.0. Under UV irradiation in air atmosphere at pH 7.0, the reactive oxygen species (ROS) including O2- and OH generated by Fe(III)-citrate through the photo-Fenton reaction accelerated the As release and oxidation. However, Fe(III)-citrate photolysis led to the rapid flocculation and precipitation of dissolved iron ions, inhibiting the further oxidation of arsenopyrite. With increasing pH from 5.0 to 9.0, the As release rate gradually decreased under UV irradiation. Increases in the concentrations of citrate and dissolved oxygen promoted the formation of Fe(III)-citrate and ROS in the reaction system under both UV irradiation and dark conditions. The present work expands our understanding of the geochemical behavior of As in near-neutral pH environment.
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Affiliation(s)
- Jun Hong
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China
| | - Lihu Liu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China
| | - Wenfeng Tan
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China
| | - Guohong Qiu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China.
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16
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Lee JH, Park MH, Song HJ, Kim PJ. Unexpected high reduction of methane emission via short-term aerobic pre-digestion of green manured soils before flooding in rice paddy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 711:134641. [PMID: 31822416 DOI: 10.1016/j.scitotenv.2019.134641] [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: 07/31/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
Soil organic matter (SOM) is used as an important indicator of soil quality and a countermeasure to mitigate global warming. To increase SOM stock, cover cropping and its biomass incorporation as green manure are strongly recommended in mono-rice paddy soils. However, green manure application significantly increased greenhouse gas emission, in particular, methane (CH4) during rice cultivation, and then its simultaneous positive and negative outcome has become a serious issue. We hypothesized that the short-term aerobic pre-digestion of green manured soil under dry soil condition before flooding might degrade labile organic C into carbon dioxide (CO2) and then reduce CH4 production during the flooded rice cultivation period. In order to evaluate the feasibility of the short-term aerobic pre-digestion of green manured soil on reducing CH4 emission in rice paddy, cover crop biomass was incorporated in the inner dry soil at different time intervals from 0 to 30 days before flooding, and then CH4 and CO2 emission rates were monitored. Over 10 days of aerobic pre-digestion significantly decreased CH4 flux by 88-98% over the control (flooded soil without aerobic pre-digestion) during the two month's incubation test. Similar results were observed during the field test, in which only at 10 days' aerobic pre-digestion under dry soil condition, total CH4 flux decreased by approximately 60% over the control. This reduction effect was slightly increased when aerobic pre-digestion period was extended. In contrast, rice productivities were not significantly different from 0 to 30 days of aerobic pre-digestion. As a result, more than 10 days of aerobic pre-digestion of green manured soil before flooding decreased CH4 flux intensity (kg CH4 kg-1 grain) by 60% over the control. In conclusion, the short-term aerobic pre-digestion of green manured soil before flooding can be a good soil management strategy to mitigate CH4 emission without productivity decrease in rice field.
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Affiliation(s)
- Jin Ho Lee
- Division of Applied Life Science (BK 21+ Program), Gyeongsang National University, Jinju 52828, South Korea
| | - Mun Hyeong Park
- Division of Applied Life Science (BK 21+ Program), Gyeongsang National University, Jinju 52828, South Korea
| | - Hyeon Ji Song
- Division of Applied Life Science (BK 21+ Program), Gyeongsang National University, Jinju 52828, South Korea
| | - Pil Joo Kim
- Division of Applied Life Science (BK 21+ Program), Gyeongsang National University, Jinju 52828, South Korea; Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju 52828, South Korea.
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17
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Zhang H, Lu T, Shang Z, Li Y, He J, Liu S, Li D, Zhou Y, Qi Z. Transport of Cd 2+ through saturated porous media: Insight into the effects of low-molecular-weight organic acids. WATER RESEARCH 2020; 168:115182. [PMID: 31634706 DOI: 10.1016/j.watres.2019.115182] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 10/01/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Low-molecular-weight organic acids (LMWOAs) are ubiquitous in the aquatic environment and consequently may affect the heavy metal transport in aquifer systems. In this study, the influences of LMWOAs on the transport of Cd2+ under different pH conditions in saturated porous media were evaluated. For this, three LMWOAs such as acetic acid, tartaric acid, and citric acid were employed. A two-site nonequilibrium transport model was applied to simulate the transport data. Under acidic conditions (pH 5.0), the results indicated that LMWOAs inhibited the transport of Cd2+ even at the low concentrations of organic acids (i.e., 0.05 and 0.1 mM). The inhibition effects might be attributed to the complexation role of the sand surface-bound organic acids and also electrostatic interaction. Meanwhile, the inhibition effects of LMWOAs on Cd2+ transport in the following order of citric acid > tartaric acid > acetic acid, which was also in agreement with the decreasing complex stability constants between Cd2+ and LMWOAs. This order may be dependent on their molecular structures (i.e., amount and type of functional groups) and complexing strength. Interestingly, when the LMWOA concentrations 0.5 mM, tartaric acid and citric acid still inhibited Cd2+ transport, while acetic acid slightly enhanced the Cd2+ mobility due to its weaker complexing strength. However, under neutral conditions (pH 7.0), LMWOAs generally enhanced the transport of Cd2+. The transport-enhancement of LMWOAs was ascribed to the formation of stable aqueous non-adsorbing Cd-organic acid complexes. In addition, citric acid could obviously inhibit the transport of Cd2+ under competitive transport conditions (i.e., with competing cations), which is mainly due to different complex affinities of citric acid to Pb2+ and Cd2+. These findings demonstrate that LMWOAs may inhibit or facilitate Cd2+ transport under different environmental conditions. Thus, environmental assessment concerning the transport of heavy metals should consider the roles of organic acids.
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Affiliation(s)
- Haojing Zhang
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China
| | - Taotao Lu
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, 300350, China; Department of Hydrology, University of Bayreuth, Bayreuth, D-95440, Germany
| | - Zhongbo Shang
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China
| | - Yanxiang Li
- The Testing Center of Shandong Bureau of China Metallurgical Geology Bureau, Jinan, 250014, China
| | - Jianying He
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China
| | - Shanhu Liu
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China
| | - Deliang Li
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China
| | - Yanmei Zhou
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China
| | - Zhichong Qi
- Henan Joint International Research Laboratory of Environmental Pollution Control Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China; Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, 300350, China.
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18
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Yan S, Liu Y, Lian L, Li R, Ma J, Zhou H, Song W. Photochemical formation of carbonate radical and its reaction with dissolved organic matters. WATER RESEARCH 2019; 161:288-296. [PMID: 31202115 DOI: 10.1016/j.watres.2019.06.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/28/2019] [Accepted: 06/01/2019] [Indexed: 05/27/2023]
Abstract
The carbonate radical (CO3•-) is a strong oxidative radical that is generated via the reactions of HCO3-/CO32- with hydroxyl radical (HO•) or triplet states of dissolved organic matter (3DOM∗) in sunlit surface water. The bimolecular reaction rate constants of CO3•- with various DOM isolates ( [Formula: see text] ) were calculated as 15-239 (mg of C/L)-1 s-1 and were correlate to the bulk DOM properties, such as the content of phenolic moieties, the specific UV absorbance (SUVA), the E2/E3 value, and the fluorescence index (FI). The spectroscopic E2/E3 values was found to strongly correlated (R2 = 0.93) with [Formula: see text] , and an empirical equation was established. Our results also demonstrate that CO3•- is involved in the photobleaching of dissolved organic matter (DOM) and in particular reacts with electron-donor moieties, leading to faster decay rates at long wavelengths of UV-vis absorption. Furthermore, a model was developed to calculate the steady-state concentrations of CO3•- during DOM photobleaching. These results allow us to estimate the reactivity of DOM with CO3•- and to evaluate the role of CO3•- in sunlit surface water. It will also allow a better assessment of the concentration and utilization of CO3•- during the application of advanced oxidation processes.
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Affiliation(s)
- Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China
| | - Yingjie Liu
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Lushi Lian
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Rui Li
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Jianzhong Ma
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Huaxi Zhou
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
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Primary Colonizing Betaproteobacteriales Play a Key Role in the Growth of Legionella pneumophila in Biofilms on Surfaces Exposed to Drinking Water Treated by Slow Sand Filtration. Appl Environ Microbiol 2018; 84:AEM.01732-18. [PMID: 30291115 DOI: 10.1128/aem.01732-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/28/2018] [Indexed: 02/05/2023] Open
Abstract
Slow sand filtration with extensive pretreatment reduces the microbial growth potential of drinking water to a minimum level at four surface water supplies in The Netherlands. The potential of these slow sand filtrates (SSFs) to promote microbial growth in warm tap water installations was assessed by measuring biofilm formation and growth of Legionella bacteria on glass and chlorinated polyvinylchloride (CPVC) surfaces exposed to SSFs at 37 ± 2°C in a model system for up to six months. The steady-state biofilm concentration ranged from 230 to 3,980 pg ATP cm-2 on glass and 1.4 (±0.3)-times-higher levels on CPVC. These concentrations correlated significantly with the assimilable organic carbon (AOC) concentrations of the warm water (8 to 24 µg acetate-C equivalents [ac-C eq] liter-1), which were raised about 2 times by mixing cold and heated (70°C) SSFs. All biofilms supported growth of Legionella pneumophila with maximum concentrations ranging from 6 × 102 to 1.5 × 105 CFU cm-2 Biofilms after ≤50 days of exposure were predominated by Betaproteobacteriales, mainly Piscinibacter, Caldimonas, Methyloversatilis, and an uncultured Rhodocyclaceae bacterium. These rapidly growing primary colonizers most likely served as prey for the host amoebae of L. pneumophila Alphaproteobacteria, mostly Xanthobacteraceae, e.g., Bradyrhizobium, Pseudorhodoplanes, and other amoeba-resistant bacteria, accounted for 37.5% of the clones retrieved. A conceptual model based on a quadratic relationship between the L. pneumophila colony count and the biofilm concentration under steady-state conditions is used to explain the variations in the Legionella CFU pg-1 ATP ratios in the biofilms.IMPORTANCE Proliferation of L. pneumophila in premise plumbing poses a public health threat. Extended water treatment using physicochemical and biofiltration processes, including slow sand filtration, at four surface water supplies in The Netherlands reduces the microbial growth potential of the treated water to a minimum level, and the distributed drinking water complies with high quality standards. However, heating of the water in warm tap water installations increases the concentration of easily assimilable organic compounds, thereby promoting biofilm formation and growth of L. pneumophila Prevention of biofilm formation in plumbing systems by maintenance of a disinfectant residual during distribution and/or further natural organic matter (NOM) removal is not feasible in the supplies studied. Temperature management in combination with optimized hydraulics and material selection are therefore essential to prevent growth of L. pneumophila in premise plumbing systems. Still, reducing the concentration of biodegradable compounds in drinking water by appropriate water treatment is important for limiting the Legionella growth potential.
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Chen N, Fang G, Liu G, Zhou D, Gao J, Gu C. The effects of Fe-bearing smectite clays on OH formation and diethyl phthalate degradation with polyphenols and H 2O 2. JOURNAL OF HAZARDOUS MATERIALS 2018; 357:483-490. [PMID: 29936346 DOI: 10.1016/j.jhazmat.2018.06.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/19/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
The natural formation of hydroxyl radicals (OH) is important for the attenuation of organic contaminants. In this study, seven model polyphenols were selected to react with four types of smectite clays with varied Fe contents in the presence of H2O2. Diethyl phthalate (DEP) was selected as a model organic contaminant due to its wide distribution in environment. The results show the appearance of Fe-bearing smectite clays can significantly promote ·OH formation with polyphenols and H2O2 under anoxic conditions; clay particle size, the content and location of lattice Fe in smectite clays greatly affect OH formation. Hydrogen bond between phenolic group and smectite surfaces, and cation assisted hydrogen bond between carboxylic group and clay surfaces are important types of complexation. Electrons can be transferred from coordinated polyphenols to structural Fe(III) atoms in tetrahedral layers or at broken edges to form structural Fe(II) and/or semiquinone radicals, both of which can induce H2O2 decomposition to OH. DEP can be degraded by OH attack, and the main products are proposed as phthalic acid, monomethyl phthalate, hydroxyl-diethyl phthalates. Our findings suggest that Fe(III)-bearing smectite clay can be reduced by polyphenol and produce OH in anoxic environments, which can induce organic contaminants transformation.
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Affiliation(s)
- Ning Chen
- Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science, CAS, Nanjing, Jiangsu Province, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guodong Fang
- Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science, CAS, Nanjing, Jiangsu Province, 210008, China
| | - Guangxia Liu
- Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science, CAS, Nanjing, Jiangsu Province, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongmei Zhou
- Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science, CAS, Nanjing, Jiangsu Province, 210008, China
| | - Juan Gao
- Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science, CAS, Nanjing, Jiangsu Province, 210008, China.
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse School of the Environment, Nanjing University, Nanjing, Jiangsu Province, 210023, China.
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Zhou Z, Zhou M, Yang X, Niu J, Meng F. Sunlight irradiation triggers changes in the fouling potentials of natural dissolved organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 627:227-234. [PMID: 29426145 DOI: 10.1016/j.scitotenv.2018.01.222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 01/22/2018] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
Sunlight-initiated photodegradation has a great impact on the composition and properties of natural dissolved organic matter (DOM) in aquatic environments, which potentially changes the behavior and roles of DOM in water treatment facilities. Here, we explored the effect of sunlight irradiation on membrane fouling behavior of two natural DOM (i.e., Aldrich humic acid (AHA) and Suwannee River DOM (SRNOM)), particularly in the presence of calcium ion (Ca(II)). Results showed that a long-term exposure (3 months) to sunlight during the summer led to decreases in the chromophores and molecular size of both DOM. The characterization by UV-vis spectral parameter DSlope350-400 (the slope of the log-transformed absorbance spectra in the range of 350-400 nm) indicated that sunlight-exposed DOM had a weaker Ca(II)-binding ability than unirradiated DOM, which could be attributable to the photochemically induced loss of carboxyl and phenolic groups. Additionally, AHA was found to be more susceptible to sunlight irradiation and Ca(II) addition than SRNOM, likely due to its higher aromaticity. Crucially, dead-end ultrafiltration tests showed that sunlight exposure of both AHA and SRNOM can reduce their fouling potential in the absence of Ca(II) and the presence of low Ca(II) (0.4 mM). In contrast, the addition of higher Ca(II) concentrations (2 and 3.6 mM) led to an increase in their fouling propensities. Overall, sunlight exposure can greatly alter the fouling behavior of natural DOM. This study provides a nexus between the naturally occurring transformation of DOM and its behavior (i.e., membrane fouling) in water treatment facilities.
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Affiliation(s)
- Zhongbo Zhou
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Minghao Zhou
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Xiaofang Yang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Junfeng Niu
- School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, PR China
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China.
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22
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Lv J, Li D, Luo L, Wu T, Zhang S. Molecular transformation of natural and anthropogenic dissolved organic matter under photo-irradiation in the presence of nano TiO 2. WATER RESEARCH 2017; 125:201-208. [PMID: 28863342 DOI: 10.1016/j.watres.2017.08.051] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/23/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
Photochemical transformation of dissolved organic matter (DOM) plays a very important role in the cycling of organic carbon in aquatic systems. Increasing release of photoactive nanoparticles such as titanium dioxide nanoparticles (nano TiO2) into surface water may impact this process. The present study employed Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to examine the molecular transformation of natural DOM (peat DOM, DOMp) and anthropogenic DOM (sludge-derived DOM, DOMs) under photo-irradiation as affected by nano TiO2. Differences in molecular components between DOMp and DOMs were observed. DOMs contained more heteroatom formulas (76%) with low aromaticity and low carbon oxidation state than did DOMp (22%). The presence of nano TiO2 resulted in significant decreases in both DOM content and molecular diversity under photo-irradiation. Consistent alterations were observed between DOMp and DOMs such that high molecular weight compounds, high aromaticity and/or heteroatom S-containing compounds were more easily photodegraded in the presence of nano TiO2; whereas the average carbon oxidation state decreased in DOMp but increased in DOMs, likely due to the significant differences in O abundance, especially in the contents of carboxyl moieties, between DOMp and DOMs. The findings of the present study suggest that the release of nano TiO2 into aquatic environment will accelerate the consumption of dissolved organic carbon and the attenuation of molecular diversity for both DOM in waters.
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Affiliation(s)
- Jitao Lv
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Dan Li
- School of Environmental Science and Engineering, Hebei University of Science and Technology, Hebei, 050018, China
| | - Lei Luo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tong Wu
- School of Environmental Science and Engineering, Hebei University of Science and Technology, Hebei, 050018, China
| | - Shuzhen Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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23
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Dutta Majumdar R, Bliumkin L, Lane D, Soong R, Simpson M, Simpson AJ. Analysis of DOM phototransformation using a looped NMR system integrated with a sunlight simulator. WATER RESEARCH 2017; 120:64-76. [PMID: 28478296 DOI: 10.1016/j.watres.2017.04.067] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/26/2017] [Accepted: 04/28/2017] [Indexed: 06/07/2023]
Abstract
Photochemical transformation plays an important role in functionalizing and degrading dissolved organic matter (DOM), producing one of the most complex mixtures known. In this study, using a flow-based design, nuclear magnetic resonance (NMR) spectroscopy is directly interfaced with a sunlight simulator enabling the study of DOM photodegradation in situ with high temporal resolution over 5 days. Samples from Suwannee River (Florida), Nordic Reservoir (Norway), and Pony Lake (Antarctic) are studied. Phototransformation of DOM is dominated by the degradation of aromatics and unsaturated structures (many arising from lignin) into carboxylated and hydroxylated products. To assess longer term changes, the samples were continuously irradiated for 17.5 days, followed by the identification a wide range of compounds and assessment of their fate using off-line 2D-NMR. This study demonstrates the applicability of the looped system to follow degradation in a non-targeted fashion (the mixture as a whole) and target analysis (tracing specific metabolites), which holds great potential to study the fate and transformation of contaminants and nutrients in the presence of DOM. It also demonstrates that components that remain unresolved in 1D NMR can be identified using 2D methods.
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Affiliation(s)
- Rudraksha Dutta Majumdar
- Environmental NMR Centre, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - Liora Bliumkin
- Environmental NMR Centre, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - Daniel Lane
- Environmental NMR Centre, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - Ronald Soong
- Environmental NMR Centre, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - Myrna Simpson
- Environmental NMR Centre, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - André J Simpson
- Environmental NMR Centre, Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada.
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24
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Song G, Li Y, Hu S, Li G, Zhao R, Sun X, Xie H. Photobleaching of chromophoric dissolved organic matter (CDOM) in the Yangtze River estuary: kinetics and effects of temperature, pH, and salinity. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:861-873. [PMID: 28548140 DOI: 10.1039/c6em00682e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The kinetics and temperature-, pH- and salinity-dependences of photobleaching of chromophoric dissolved organic matter (CDOM) in the Yangtze River estuary (YRE) were evaluated using laboratory solar-simulated irradiation and compared to those of Suwannee River humic substances (SRHSs). Nearly all CDOM in water at the head of the estuary (headwater herein) was photobleachable in both summer and winter, while significant fractions of CDOM (13-29%) were resistant to photobleaching in saltier waters. The photobleaching rate constant in the headwater was 25% higher in summer than that in winter. The absorbed photon-based photobleaching efficiency (PE) increased with temperature following the linear Arrhenius equation. For a 20 °C increase in temperature, PE increased by ∼45% in the headwater and by 70-81% in the saltier waters. PE for YRE samples exhibited minima at pH from 6 to 7 and increased with both lower and higher pH values, contrasting the consistent increase in PE with pH shown by SRHSs. No consistent effect of salinity on PE was observed for both SRHSs and YRE samples. Photobleaching increased the spectral slope coefficient between 275 nm and 295 nm in summer, consistent with the behavior of SRHSs, but decreased it in winter, implying a difference in the molecular composition of chromophores between the two seasons. Temperature, salinity, and pH modified the photoalteration of the spectral shape but their effects varied spatially and seasonally. This study demonstrates that CDOM quality, temperature, and pH should be incorporated into models involving quantification of photobleaching.
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Affiliation(s)
- Guisheng Song
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, Tianjin 300457, China
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25
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Kim MK, Won AY, Zoh KD. Effects of molecular size fraction of DOM on photodegradation of aqueous methylmercury. CHEMOSPHERE 2017; 174:739-746. [PMID: 28214421 DOI: 10.1016/j.chemosphere.2017.02.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/26/2017] [Accepted: 02/05/2017] [Indexed: 06/06/2023]
Abstract
This study investigated the photodegradation kinetics of MeHg in the presence of various size fractions of dissolved organic matter (DOM) with MW < 3.5 kDa, 3.5 < MW < 10 kDa, and MW > 10 kDa. The DOM fraction with MW < 3.5 kDa was most effective in MeHg photodegradation. Increasing UV intensity resulted in the increase of photodegradation rate of the MeHg in all size of DOM fractions. Higher rates of MeHg degradation was observed at higher pH. For the portion of MW < 3.5 kDa, the photodegradation rate of MeHg increased with increasing DOM concentration, indicating that radicals such as singlet oxygen (1O2) radicals can be effectively produced by DOM. At higher portion of MW > 3.5 kDa, the inhibition of MeHg degradation was observed due to the effect of DOM photo-attenuation. Our result indicates that radical mediated reaction is the main mechanism of photodegradation of MeHg especially in the presence of MW < 3.5 kDa. Our results imply that the smaller molecular weight fraction (MW < 3.5 kDa) of DOM mainly increased the photodegradation rate of MeHg.
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Affiliation(s)
- Moon-Kyung Kim
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, South Korea; Institute of Health & Environment, Seoul National University, Seoul 08826, South Korea
| | - A-Young Won
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, South Korea
| | - Kyung-Duk Zoh
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul 08826, South Korea; Institute of Health & Environment, Seoul National University, Seoul 08826, South Korea.
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26
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Qin J, Li Y, Li S, Li H, Lin C. Potential effects of rainwater-borne H 2O 2 on competitive degradation of herbicides and in the presence of humic acid. CHEMOSPHERE 2017; 170:146-152. [PMID: 27987462 DOI: 10.1016/j.chemosphere.2016.12.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/28/2016] [Accepted: 12/04/2016] [Indexed: 06/06/2023]
Abstract
In a previous piece of work, we reported some preliminary experimental results showing that hydrogen peroxide at a concentration range frequently encountered in rainwater could lead to degradation of three common herbicides (diuron, butachlor and glyphosate). However, the work was limited to the observation on the effects of Fenton process on the individual herbicides. In field conditions, different types of herbicides along with other organic molecules may occur concurrently. It is unclear how different herbicides and various organic molecules compete for the available hydroxyl radical. In this study, further laboratory experiments were conducted to observe the changes in the herbicides in the scenarios where multiple herbicides or humic acid are present. The results show that humic acid impeded hydroxyl radical-driven degradation of the diuron and butachlor. However, humic acid had no significant effects on reducing glyphosate removal rate. Glyphosate could compete strongly with the humic acid for the available hydroxyl radical in the reaction systems. The reactivity of glyphosate with hydroxyl radical was much higher than those of diuron and butachlor due possibly to its relatively simpler chemical structure, as compared to either diuron or butachlor, which are aromatic compounds that have higher chemical stability. Butachlor degradation was much weaker in the combined diuron and butachlor system than in the combined glyphosate and butachlor system. In the glyphosate-butachlor system, the opposite was observed. The findings have moved another step forward to understanding the potential role of rainwater-borne H2O2 in degrading herbicides in open water environments.
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Affiliation(s)
- Junhao Qin
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China; School of Environment and Life Science, University of Salford, Greater Manchester, M5 4WT, United Kingdom
| | - Yongjun Li
- Zhongshan Quality Supervision and Inspection Institute of Agricultural Products, Zhongshan, China
| | - Shengan Li
- Zhongshan Quality Supervision and Inspection Institute of Agricultural Products, Zhongshan, China
| | - Huashou Li
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China
| | - Chuxia Lin
- School of Environment and Life Science, University of Salford, Greater Manchester, M5 4WT, United Kingdom.
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27
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van der Kooij D, Bakker GL, Italiaander R, Veenendaal HR, Wullings BA. Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant. Appl Environ Microbiol 2017; 83:e02737-16. [PMID: 28062459 PMCID: PMC5311405 DOI: 10.1128/aem.02737-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 12/13/2016] [Indexed: 02/07/2023] Open
Abstract
Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm-2) exposed to treated aerobic groundwater (0.3 mg C liter-1; 1 μg assimilable organic carbon [AOC] liter-1) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm-2) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm-2 in the biofilms on glass (1,055 ± 225 pg ATP cm-2) and CPVC (2,755 ± 460 pg ATP cm-2) exposed to treated anaerobic groundwater (7.9 mg C liter-1; 10 μg AOC liter-1). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis This amoeba was rarely detected at biofilm concentrations of <100 pg ATP cm-2 A threshold concentration of approximately 50 pg ATP cm-2 (TCC = 1 × 106 to 2 × 106 cells cm-2) was derived for growth of L. pneumophila in biofilms.IMPORTANCELegionella pneumophila is the etiologic agent in more than 10,000 cases of Legionnaires' disease that are reported annually worldwide and in most of the drinking water-associated disease outbreaks reported in the United States. The organism proliferates in biofilms on surfaces exposed to warm water in engineered freshwater installations. An investigation with a test system supplied with different types of warm drinking water without disinfectant under controlled hydraulic conditions showed that treated aerobic groundwater (0.3 mg liter-1 of organic carbon) induced a low biofilm concentration that supported no or very limited growth of L. pneumophila Elevated biofilm concentrations and L. pneumophila colony counts were observed on surfaces exposed to two types of extensively treated groundwater, containing 1.8 and 7.9 mg C liter-1 and complying with the microbial water quality criteria during distribution. Control measures in warm tap water installations are therefore essential for preventing growth of L. pneumophila.
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Affiliation(s)
| | | | | | | | - Bart A Wullings
- KWR Watercycle Research Institute, Nieuwegein, the Netherlands
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28
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Doane TA. A survey of photogeochemistry. GEOCHEMICAL TRANSACTIONS 2017; 18:1. [PMID: 28246525 PMCID: PMC5307419 DOI: 10.1186/s12932-017-0039-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/28/2017] [Indexed: 05/08/2023]
Abstract
The participation of sunlight in the natural chemistry of the earth is presented as a unique field of study, from historical observations to prospects for future inquiry. A compilation of known reactions shows the extent of light-driven interactions between naturally occurring components of land, air, and water, and provides the backdrop for an outline of the mechanisms of these phenomena. Catalyzed reactions, uncatalyzed reactions, direct processes, and indirect processes all operate in natural photochemical transformations, many of which are analogous to well-known biological reactions. By overlaying photochemistry and surface geochemistry, complementary approaches can be adopted to identify natural photochemical reactions and discern their significance in the environment.
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Affiliation(s)
- Timothy A. Doane
- Department of Land, Air and Water Resources, University of California, Davis, Davis, CA 95616-5270 USA
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29
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Romonosky DE, Li Y, Shiraiwa M, Laskin A, Laskin J, Nizkorodov SA. Aqueous Photochemistry of Secondary Organic Aerosol of α-Pinene and α-Humulene Oxidized with Ozone, Hydroxyl Radical, and Nitrate Radical. J Phys Chem A 2017; 121:1298-1309. [DOI: 10.1021/acs.jpca.6b10900] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Dian E. Romonosky
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Ying Li
- National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan
| | - Manabu Shiraiwa
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | | | | | - Sergey A. Nizkorodov
- Department
of Chemistry, University of California, Irvine, California 92697, United States
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30
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Bliumkin L, Dutta Majumdar R, Soong R, Adamo A, Abbatt JPD, Zhao R, Reiner E, Simpson AJ. Development of an in Situ NMR Photoreactor To Study Environmental Photochemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5506-5516. [PMID: 27172272 DOI: 10.1021/acs.est.6b00361] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Photochemistry is a key environmental process directly linked to the fate, source, and toxicity of pollutants in the environment. This study explores two approaches for integrating light sources with nuclear magnetic resonance (NMR) spectroscopy: sample irradiation using a "sunlight simulator" outside the magnet versus direct irradiation of the sample inside the magnet. To assess their applicability, the in situ NMR photoreactors were applied to a series of environmental systems: an atmospheric pollutant (p-nitrophenol), crude oil extracts, and groundwater. The study successfully illustrates that environmentally relevant aqueous photochemical processes can be monitored in situ and in real time using NMR spectroscopy. A range of intermediates and degradation products were identified and matched to the literature. Preliminary measurements of half-lives were also obtained from kinetic curves. The sunlight simulator was shown to be the most suitable model to explore environmental photolytic processes in situ. Other light sources with more intense UV output hold potential for evaluating UV as a remediation alternative in areas such as wastewater treatment plants or oil spills. Finally, the ability to analyze the photolytic fate of trace chemicals at natural abundance in groundwater, using a cryogenic probe, demonstrates the viability of NMR spectroscopy as a powerful and complementary technique for environmental applications in general.
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Affiliation(s)
- Liora Bliumkin
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
| | | | | | | | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
| | - Ran Zhao
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
| | - Eric Reiner
- Ontario Ministry of the Environment , Toronto, Ontario M9P 3 V6, Canada
| | - André J Simpson
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada
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31
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Ng TW, Huang G, Wong PK. Investigation of drinking water bacterial community through high-throughput sequencing. J Environ Sci (China) 2015; 37:154-156. [PMID: 26574098 DOI: 10.1016/j.jes.2015.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Tsz Wai Ng
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, SAR, China
| | - Guocheng Huang
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, SAR, China
| | - Po Keung Wong
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, SAR, China.
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32
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Worms IAM, Adenmatten D, Miéville P, Traber J, Slaveykova VI. Photo-transformation of pedogenic humic acid and consequences for Cd(II), Cu(II) and Pb(II) speciation and bioavailability to green microalga. CHEMOSPHERE 2015; 138:908-915. [PMID: 25563161 DOI: 10.1016/j.chemosphere.2014.10.093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 10/01/2014] [Accepted: 10/21/2014] [Indexed: 06/04/2023]
Abstract
Humic substances (HS) play key role in toxic metal binding and protecting aquatic microorganisms from metal-induced stress. Any environmental changes that could alter HS concentration and reactivity can be expected to modify metal complexation and thus affect metal speciation and bioavailability to microalgae. The present study explores the influence of increased solar irradiance on the chemical structures and molecular weight of Elliott soil humic acid (EHA) and the associated consequences for Cd(II), Cu(II) and Pb(II) complexation and intracellular metal content in microalga. The results demonstrate that high radiance doses induce an oxidation of EHA with a formation of low molecular weight acids, an increase of -OH and -COOH group abundance, and a drop in EHA hydrodynamic size and molecular weight. The photo-induced structural changes are accompanied with a release of metal from M-EHA complexes and narrowing their size distribution, which in turn results in an increase of the intracellular Cd, Cu and Pb contents in microalga Chlamydomonas reinhardtii in agreement with the measured free metal ions concentrations.
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Affiliation(s)
- Isabelle A M Worms
- Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 10, route de Suisse, CH-1290 Versoix, Switzerland.
| | - David Adenmatten
- Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 10, route de Suisse, CH-1290 Versoix, Switzerland
| | - Pascal Miéville
- Institute of Chemical Sciences and Engineering, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, Station 6, Switzerland
| | - Jacqueline Traber
- Process Engineering, Eawag, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland
| | - Vera I Slaveykova
- Environmental Biogeochemistry and Ecotoxicology, Institute F.-A. Forel, Earth and Environmental Sciences, Faculty of Sciences, University of Geneva, 10, route de Suisse, CH-1290 Versoix, Switzerland.
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33
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Sandron S, Rojas A, Wilson R, Davies NW, Haddad PR, Shellie RA, Nesterenko PN, Kelleher BP, Paull B. Chromatographic methods for the isolation, separation and characterisation of dissolved organic matter. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2015; 17:1531-1567. [PMID: 26290053 DOI: 10.1039/c5em00223k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This review presents an overview of the separation techniques applied to the complex challenge of dissolved organic matter characterisation. The review discusses methods for isolation of dissolved organic matter from natural waters, and the range of separation techniques used to further fractionate this complex material. The review covers both liquid and gas chromatographic techniques, in their various modes, and electrophoretic based approaches. For each, the challenges that the separation and fractionation of such an immensely complex sample poses is critically reviewed.
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Affiliation(s)
- Sara Sandron
- Australian Centre for Research on Separation Sciences (ACROSS), University of Tasmania, Private Bag 75, Hobart, Tasmania, Australia 7001.
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34
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Pittaway P, Herzig M, Stuckey N, Larsen K. Biodegradation of artificial monolayers applied to water storages to reduce evaporative loss. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2015; 72:1334-1340. [PMID: 26465303 DOI: 10.2166/wst.2015.348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Repeat applications of an artificial monolayer to the interfacial boundary layer of large agricultural water storages during periods of high evaporative demand remains the most commercially feasible water conservation strategy. However, the interfacial boundary layer (or microlayer) is ecologically distinct from subsurface water, and repeat monolayer applications may adversely affect microlayer processes. In this study, the natural cleansing mechanisms operating within the microlayer were investigated to compare the biodegradability of two fatty alcohol (C16OH and C18OH) and one glycol ether (C18E1) monolayer compound. The C16OH and C18OH compounds were more susceptible to microbial degradation, but the C18E1 compound was most susceptible to indirect photodegradation. On clean water the surface pressure and evaporation reduction achieved with a compressed C18E1 monolayer was superior to the C18OH monolayer, but on brown water the surface pressure dropped rapidly. These results suggest artificial monolayers are readily degraded by the synergy between photo and microbial degradation. The residence time of C18OH and C18E1 monolayers on clear water is sufficient for cost-effective water conservation. However, the susceptibility of C18E1 to photodegradation indicates the application of this monolayer to brown water may not be cost-effective.
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Affiliation(s)
- P Pittaway
- National Centre for Engineering in Agriculture, University of Southern Queensland, West St, Toowoomba, 4350 Australia E-mail:
| | - M Herzig
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, 4072 Australia
| | - N Stuckey
- National Centre for Engineering in Agriculture, University of Southern Queensland, West St, Toowoomba, 4350 Australia E-mail:
| | - K Larsen
- Faculty of Sciences, University of Southern Queensland, Toowoomba, 4350 Australia
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35
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De Laurentiis E, Minella M, Maurino V, Minero C, Vione D. Effects of climate change on surface-water photochemistry: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:11770-80. [PMID: 24310903 DOI: 10.1007/s11356-013-2343-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/04/2013] [Indexed: 05/23/2023]
Abstract
Information concerning the link between surface-water photochemistry and climate is presently very scarce as only a few studies have been dedicated to the subject. On the basis of the limited knowledge that is currently available, the present inferences can be made as follows: (1) Warming can cause enhanced leaching of ionic solutes from the catchments to surface waters, including cations and more biologically labile anions such as sulphate. Preferential sulphate biodegradation followed by removal as organic sulphides in sediment could increase alkalinity, favouring the generation of the carbonate radical, CO3 (·-). However, this phenomenon would be easily offset by fluctuations of the dissolved organic carbon (DOC), which is strongly anticorrelated with CO3 (·-). Therefore, obtaining insight into DOC evolution is a key issue in understanding the link between photochemistry and climate. (2) Climate change could exacerbate water scarcity in the dry season in some regions. Fluctuations in the water column could deeply alter photochemistry that is usually favoured in shallower waters. However, the way water is lost would strongly affect the prevailing photoinduced processes. Water outflow without important changes in solute concentration would mostly favour reactions induced by the hydroxyl and carbonate radicals (·OH and CO3 (·-)). In contrast, evaporative concentration would enhance reactions mediated by singlet oxygen ((1)O2) and by the triplet states of chromophoric dissolved organic matter ((3)CDOM*). (3) In a warmer climate, the summer stratification period of lakes would last longer, thereby enhancing photochemical reactions in the epilimnion but at the same time keeping the hypolimnion water in the dark for longer periods.
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Affiliation(s)
- Elisa De Laurentiis
- Department of Chemistry, University of Torino, Via P. Giuria 5, 10125, Turin, Italy,
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36
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Langlois MC, Weavers LK, Chin YP. Contaminant-mediated photobleaching of wetland chromophoric dissolved organic matter. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2098-2107. [PMID: 24828085 DOI: 10.1039/c4em00138a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Photolytic transformation of organic contaminants in wetlands can be mediated by chromophoric dissolved organic matter (CDOM), which in turn can lose its reactivity from photobleaching. We collected water from a small agricultural wetland (Ohio), Kawai Nui Marsh (Hawaii), the Everglades (Florida), and Okefenokee Swamp (Georgia) to assess the effect of photobleaching on the photofate of two herbicides, acetochlor and isoproturon. Analyte-spiked water samples were irradiated using a solar simulator and monitored for changes in CDOM light absorbance and dissolved oxygen. Photobleaching did not significantly impact the indirect photolysis rates of either herbicide over 24 hours of irradiation. Surprisingly, the opposite effect was observed with isoproturon, which accelerated DOM photobleaching. This phenomenon was more pronounced in higher-CDOM waters, and we believe that the redox pathway between triplet-state CDOM and isoproturon may be responsible for our observations. By contrast, acetochlor indirect photolysis was dependent on reaction with the hydroxyl radical and did not accelerate photobleaching of wetland water as much as isoproturon. Finally, herbicide indirect photolysis rate constants did not correlate strongly to any one chemical or optical property of the sampled waters.
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Affiliation(s)
- Maureen C Langlois
- Environmental Science Graduate Program, The Ohio State University, Columbus, OH 43210, USA
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Calza P, Vione D, Minero C. The role of humic and fulvic acids in the phototransformation of phenolic compounds in seawater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 493:411-418. [PMID: 24954562 DOI: 10.1016/j.scitotenv.2014.05.145] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 06/03/2023]
Abstract
Humic substances (HS) are known to act as photosensitizers toward the transformation of pollutants in the surface layer of natural waters. This study focused on the role played by HS toward the transformation of xenobiotics in seawater, with the purpose of assessing the prevailing degradation routes. Phenol was chosen as model xenobiotic and its transformation was investigated under simulated sunlight in the presence of terrestrial or marine humic and fulvic acids, in pure water at pH8, artificial seawater (ASW) or natural seawater (NSW). The following parameters were determined: (1) the phenol degradation rate; (2) the variation in HS concentration with irradiation time; (3) the production of transformation products; (4) the influence of iron species on the transformation process. Faster transformation of phenol was observed with humic acids (HA) compared to fulvic acids (SRFA), and transformation induced by both HA and SRFA was faster in ASW than that in pure water. These observations can be explained by assuming an interplay between different competing and sometimes opposite processes, including the competition between chloride, bromide and dissolved oxygen for reaction with HS triplet states. The analysis of intermediates formed in the different matrices under study showed the formation of several hydroxylated (hydroquinone, 1,4-benzoquinone, resorcinol) and condensed compounds (2,2'-bisphenol, 4,4'-bisphenol, 4-phenoxyphenol). Although 1,4-benzoquinone was the main transformation product, formation of condensed molecules was significant with both HA and SRFA. Experiments on natural seawater spiked with HS confirmed the favored formation of condensed products, suggesting a key role of humic matter in dimerization reactions occurring in saline water.
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Affiliation(s)
- P Calza
- Dipartimento di Chimica, Università di Torino, via P. Giuria 5, 10125 Torino, Italy.
| | - D Vione
- Dipartimento di Chimica, Università di Torino, via P. Giuria 5, 10125 Torino, Italy
| | - C Minero
- Dipartimento di Chimica, Università di Torino, via P. Giuria 5, 10125 Torino, Italy
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Ng TW, Chow AT, Wong PK. Dual roles of dissolved organic matter in photo-irradiated Fe(III)-contained waters. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2014.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Xiao M, Wu F. A review of environmental characteristics and effects of low-molecular weight organic acids in the surface ecosystem. J Environ Sci (China) 2014; 26:935-954. [PMID: 25079624 DOI: 10.1016/s1001-0742(13)60570-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 03/07/2014] [Accepted: 03/20/2014] [Indexed: 06/03/2023]
Abstract
Low molecular weight organic acids (LMWOAs) are prevalent on the earth's surface. They are vital intermediate products during metabolic pathways of organic matter and participate in the tricarboxylic acid cycle during life activities. Photochemical reactions are pivotal for LMWOAs' origination and play a large role in determining their diversity and their ultimate fate. Within the long time that organic matter is preserved in sediments, it can be decomposed and converted to release organic and inorganic pollutants as well as C, N, and P nutrients, which are of potential ecological risk in causing secondary pollution to lake water. The sediment pool is a comprehensive and complex compartment closely associated with overlying water by various biochemical processes, during which LMWOAs play critical roles to transport and transform elements. This article elucidates geochemical behaviors of LMWOAs in the surface environment in details, taking natural water, soil, and aerosol as examples, focusing on reviewing research developments on sources and characteristics, migration and mineralization of LMWOAs and relevant environmental effects. Simultaneously, this review article depicts the categories and contents of LMWOAs or their contribution to DOC in environmental media, and evaluates their importance during organic matter early diagenesis. Through concluding and discussing the conversion mechanisms and influencing factors, the next research orientations on LMWOAs in lake ecosystems are determined, mainly concerning relationships with hydrochemical parameters and microorganisms, and interactions with pollutants. This will enrich the knowledge on organic matter degradation and related environmental effects, and help reconstruct a theoretical framework for organic compound succession and influencing factors, providing basic data for lake eutrophication and ecological risk assessment, conducive to better control over water pollution and proper management of water quality.
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Affiliation(s)
- Min Xiao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
| | - Fengchang Wu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
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Timko SA, Romera-Castillo C, Jaffé R, Cooper WJ. Photo-reactivity of natural dissolved organic matter from fresh to marine waters in the Florida Everglades, USA. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:866-78. [PMID: 24549208 DOI: 10.1039/c3em00591g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Natural dissolved organic matter (DOM) is the major absorber of sunlight in most natural waters and a critical component of carbon cycling in aquatic systems. The combined effect of light absorbance properties and related photo-production of reactive species are essential in determining the reactivity of DOM. Optical properties and in particular excitation-emission matrix fluorescence spectroscopy combined with parallel factor analysis (EEM-PARAFAC) have been used increasingly to track sources and fate of DOM. Here we describe studies conducted in water from two estuarine systems in the Florida Everglades, with a salinity gradient of 2 to 37 and dissolved organic carbon concentrations from 19.3 to 5.74 mg C L(-1), aimed at assessing how the quantity and quality of DOM is coupled to the formation rates and steady-state concentrations of reactive species including singlet oxygen, hydroxyl radical, and the triplet excited state of DOM. These species were related to optical properties and PARAFAC components of the DOM. The formation rate and steady-state concentration of the carbonate radical was calculated in all samples. The data suggests that formation rates, particularly for singlet oxygen and hydroxyl radicals, are strongly coupled to the abundance of terrestrial humic-like substances. A decrease in singlet oxygen, hydroxyl radical, and carbonate radical formation rates and steady-state concentration along the estuarine salinity gradient was observed as the relative concentration of terrestrial humic-like DOM decreased due to mixing with microbial humic-like and protein-like DOM components, while the formation rate of triplet excited-state DOM did not change. Fluorescent DOM was also found to be more tightly coupled to reactive species generation than chromophoric DOM.
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Affiliation(s)
- Stephen A Timko
- Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA.
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Chow AT, Díaz FJ, Wong KH, O'Geen AT, Dahlgren RA, Wong PK. Photochemical and bacterial transformations of disinfection by-product precursors in water. JOURNAL OF ENVIRONMENTAL QUALITY 2013; 42:1589-1595. [PMID: 24216437 DOI: 10.2134/jeq2013.01.0022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In situ grab sampling from source waters and water extraction from source materials are common methods for determining disinfection by-product (DBP) formation potential (FP) of water samples or reactivity of dissolved organic matter (DOM) in forming DBPs during chlorination. However, DOM, as the main DBP precursor, collected using these techniques may not represent the DOM reacting with disinfectants due to biogeochemical alterations during water conveyance to drinking water treatment facilities. In this study, we exposed leachates from fresh litter and associated decomposed duff to natural sunlight or K-12 for 14 d and evaluated the changes, if any, on the propensity to form trihalomethane (THM), haloacetonitrile (HAN), and chloral hydrate (CHD) during chlorination. Sunlight treatment did not significantly change dissolved organic carbon (DOC) concentration but caused a 24 to 43% decrease in the specific ultraviolet absorbance (SUVA) at 254 nm, indicating that UV-active chromophores were transformed or degraded. There were significant increases ( < 0.05) in specific HAN formation potential (HAN-FP) and specific CHD formation potential (CHD-FP) (i.e., HAN and CHD formation potentials per unit carbon), but no change in specific THM formation potential (THM-FP) after sunlight exposure. In contrast, bacterial treatment did not show any significant effect on SUVA, specific chlorine demand, or any specific DBP-FPs, although bacterial colony counts suggested DOM in leachates was utilized for bacterial growth. Results of this study confirmed that the reactivity of DOM in forming DBPs could be different after biogeochemical processes compared with its source materials. For this study, photochemical reactions had a greater effect on DBP-FPs than did microbial degradation.
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Wang X, Pang H, Zhao S, Shao W, Yan B, Li X, Li S, Chen J, Du W. Ferric Phosphate Hydroxide Microcrystals for Highly Efficient Visible-Light-Driven Photocatalysts. Chemphyschem 2013; 14:2518-24. [DOI: 10.1002/cphc.201300331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Indexed: 11/10/2022]
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Xiao M, Wu F, Wang L, Li X, Huang R. Investigation of low-molecular weight organic acids and their spatiotemporal variation characteristics in Hongfeng Lake, China. J Environ Sci (China) 2013; 25:237-245. [PMID: 23596941 DOI: 10.1016/s1001-0742(12)60042-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The identities and concentrations of low-molecular-weight organic acids (LMWOAs) were determined by ion chromatography throughout a 20-m water column in Hongfeng Lake, China. The spatiotemporal variations of LMWOAs and their contributions to dissolved organic matter (DOM) in a research period of 24 hr were also investigated. The results demonstrated that five LMWOAs (lactic, acetic, pyruvic, sorbic, oxalic acid) were detected, and their total concentration and proportion in DOC were 6.55 micromol/L and 7.47%. Their average levels were 2.50, 0.65, 2.35, 0.96 and 0.09 micromol/L, respectively. LMWOAs were higher during daytime (10:00-18:00 on Jun 13, 2008) than nighttime (21:00-6:00 the next morning), in particular 4.99 micromol/L high in the epilimnion (< or = 1 m water depth), reflecting the fact that direct import from terrigenous sources and photochemical production from humic materials were dominant during LMWOAs' origin and accumulation. The same factors caused LMWOAs to be 0.63 micromol/L in the epilimnion higher than in the hypolimnion. The rapid decrease of total organic acid (TOA) up until 18:00 mainly resulted from bio-uptake and mineralization in the hypolimnion (>1 m water depth). Pyruvic acid increased with time in the epilimnion and decreased in the hypolimnion, largely related to the two contrary processes of continuous degradation and synthesis of macromolecular organic matter during life materials' cycle mediated by organisms. Simultaneously, plankton behavior and thermal stratification played a pivotal role in LMWOAs' behavior in the water column, causing decreasing and increasing profiles. The distribution of LMWOAs represents an interesting resource for biogeochemical research of DOM in aquatic ecosystems.
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Affiliation(s)
- Min Xiao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
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Stuckey NG, Larsen K. Field Determinations of Pentachlorophenol in Water Using UV/Vis Spectroscopy. Aust J Chem 2013. [DOI: 10.1071/ch12286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pentachlorophenol (PCP) is an organochloride pesticide banned in many countries due to its broad-spectrum toxicity. Current methods for monitoring PCP in environmental water require expensive laboratory equipment, limiting field monitoring. Two field methods for screening the concentration of PCP in environmental water are described herein. The first involves filtering the sample and calculating the indicative concentration from the absorbance at 320 nm. Alternatively, the sample can be acidified with concentrated hydrochloric acid to produce a fine suspension. This cloudy solution can be matched to a photo card for field estimation of concentration, or calculated more accurately from the absorbance at 450 nm. The useable ranges for these methods are 2 ppb to 100 ppm for the un-acidified method and 4 ppm to 1000 ppm for the acidified method. Results indicate that aquatic humic substances and natural turbidity present in environmental water do not compromise the results.
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Loiselle S, Vione D, Minero C, Maurino V, Tognazzi A, Dattilo AM, Rossi C, Bracchini L. Chemical and optical phototransformation of dissolved organic matter. WATER RESEARCH 2012; 46:3197-3207. [PMID: 22503589 DOI: 10.1016/j.watres.2012.02.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 02/24/2012] [Accepted: 02/29/2012] [Indexed: 05/31/2023]
Abstract
Dissolved organic matter represents the main reservoir of organic carbon in most aquatic ecosystems. In the present study, we determined the optical changes and the quantum yields of transient species formation for chromophoric dissolved organic matter (CDOM) samples undergoing photodegradation. The results show that the triplet states (3)CDOM* are potentially key players in CDOM photodegradation and that such transformations are strongly influenced by small differences in CDOM sources and sinks. In contrast, ·OH radicals are very unlikely to play a key role in phototransformation. These results represent an important first step in combining optical and transient species analyses to understand photodegradation processes of dissolved organic matter.
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Affiliation(s)
- Steven Loiselle
- Dipartamento Farmaco Chimico Tecnologico, Università degli Studi di Siena, Siena, Italy.
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He F, Zheng W, Liang L, Gu B. Mercury photolytic transformation affected by low-molecular-weight natural organics in water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 416:429-435. [PMID: 22225824 DOI: 10.1016/j.scitotenv.2011.11.081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/23/2011] [Accepted: 11/29/2011] [Indexed: 05/31/2023]
Abstract
Mechanisms by which dissolved organic matter (DOM) mediates the photochemical reduction of Hg(II) in aquatic ecosystems are not fully understood, owing to the heterogeneous nature and complex structural properties of DOM. In this work, naturally occurring aromatic compounds including salicylic, 4-hydrobenzoic, anthranilic, 4-aminobenzoic, and phthalic acid were systematically studied as surrogates for DOM in order to gain an improved mechanistic understanding of these compounds in the photoreduction of Hg(II) in water. We show that the photoreduction rates of Hg(II) are influenced not only by the substituent functional groups such as -OH, -NH(2) and -COOH on the benzene ring, but also the positioning of these functional groups on the ring structure. The Hg(II) photoreduction rate decreases in the order anthranilic acid>salicylic acid>phthalic acid according to the presence of the -NH(2), -OH, -COOH functional groups on benzoic acid. The substitution position of the functional groups affects reduction rates in the order anthranilic acid>4-aminobenzoic acid and salicylic acid>4-hydroxybenzoic acid. Reduction rates correlate strongly with ultraviolet (UV) absorption of these compounds and their concentrations, suggesting that the formation of organic free radicals during photolysis of these compounds is responsible for Hg(II) photoreduction. These results provide insight into the role of low-molecular-weight organic compounds and possibly DOM in Hg photoredox transformation and may thus have important implications for understanding Hg geochemical cycling in the environment.
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Affiliation(s)
- Feng He
- Environmental Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Nguyen TB, Laskin A, Laskin J, Nizkorodov SA. Direct aqueous photochemistry of isoprene high-NOx secondary organic aerosol. Phys Chem Chem Phys 2012; 14:9702-14. [DOI: 10.1039/c2cp40944e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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48
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Fan X, Hao H, Shen X, Chen F, Zhang J. Removal and degradation pathway study of sulfasalazine with Fenton-like reaction. JOURNAL OF HAZARDOUS MATERIALS 2011; 190:493-500. [PMID: 21497991 DOI: 10.1016/j.jhazmat.2011.03.069] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/23/2011] [Accepted: 03/21/2011] [Indexed: 05/11/2023]
Abstract
The Fenton-like degradation of sulfasalazine solution is studied in this work. The effects of reaction parameters such as Fe(3+) concentration, initial H(2)O(2) dosage and the reaction temperature are evaluated. For sulfasalazine of 100mg/L, the removal of sulfasalazine, chemical oxygen demand (COD) and total organic carbon (TOC) reached 99.5%, 84.2% and 41% in 60 min with 0.20mM Fe(3+) and 16 mM H(2)O(2) at 35°C, respectively. The complexed Fe(3+) presents a reaction constant of 0.062 min(-1)mM(-1) while that of free Fe(3+) is 2.526 min(-1)mM(-1) for sulfasalazine degradation. LC-MS technology was used to analysis the possible degradation intermediates. The degradation of sulfasalazine principally begins with the attack of hydroxyl radical on the azo-group as well as the sulfanilamido group. Both intramolecular rearrangement and bimolecular reaction occur simultaneously after the hydroxyl radical attack. Further attack of the active oxidative species results in the cleavage of the aromatic rings and the production of CO(2). The degradation of industrial sulfasalazine wastewater with a COD of 3425 mg/L has also been achieved by Fenton reaction with different dosage of H(2)O(2). Relatively better removal efficiency is observed at moderate Fe/H(2)O(2) molar ratio from 1/5 to 2/5 for industrial sulfasalazine wastewater treatment.
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Affiliation(s)
- Xiangqun Fan
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, PR China.
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Ekström SM, Kritzberg ES, Kleja DB, Larsson N, Nilsson PA, Graneli W, Bergkvist B. Effect of acid deposition on quantity and quality of dissolved organic matter in soil-water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:4733-9. [PMID: 21528901 DOI: 10.1021/es104126f] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The aim of this study was to explore how acid deposition may affect the concentration and quality of dissolved organic matter (DOM) in soil-water. This was done by a small-scale acidification experiment during two years where 0.5 × 0.5 m(2) plots were artificially irrigated with water with different sulfuric acid content, and soil-water was sampled using zero-tension lysimeters under the O-horizon. The DOM was characterized using absorbance, fluorescence, and size exclusion chromatography analyses. Our results showed lower mobility of DOM in the high acid treatment. At the same time, there was a significant change in the DOM quality. Soil-water in the high acid treatment exhibited DOM that was less colored, less hydrophobic, less aromatic, and of lower molecular weight, compared to the low acid treatment. This supports the hypothesis that reduction in sulfur deposition is an important driver behind the ongoing brownification of surface waters in many regions.
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Affiliation(s)
- Sara M Ekström
- Department of Biology/Aquatic Ecology, Lund University, Lund, Sweden.
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Li D, Pan C, Shi R, Zhu Y. Controllable synthesis of Fe5(PO4)4(OH)3·2H2O as a highly efficient heterogeneous Fenton-like catalyst. CrystEngComm 2011. [DOI: 10.1039/c1ce05483j] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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