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Mu G, Huang M, Wu Z, Cui H, Yang Q, Li X, Cui X, Tong Y. Characteristics of nutrients and microbial communities in proglacial lakes on the Tibetan Plateau and their potential linkages associated with mercury. JOURNAL OF HAZARDOUS MATERIALS 2025; 492:138117. [PMID: 40188554 DOI: 10.1016/j.jhazmat.2025.138117] [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: 12/17/2024] [Revised: 03/11/2025] [Accepted: 03/30/2025] [Indexed: 04/08/2025]
Abstract
Glacier shrinkages and evolutions of post-glacial ecosystems due to human-induced climate change represent some of the most rapidly occurring ecosystem shifts with potential ecological and societal cascading consequences on Earth. Glacial meltwater could introduce a substantial amount of nutrients, dissolved organic matter (DOM), and contaminants stored in glaciers into the lakes. However, influence of glacial meltwater on microbial communities and its impacts in the transformation of trace contaminants by microbes are frequently underestimated. This study explored the distribution of nutrients, mercury (Hg), and microbial communities across the meltwaters, surface waters, deep waters, and outflows of three proglacial lakes that formed after 2000 on the Tibetan Plateau. Our results revealed that alterations in the DOM composition, particularly the efficient metabolism of carbohydrates (CHO), may foster growth and activities of microorganisms. This could enhance the abundance of potential Hg methylators, resulting in an increase in the ratio of methylmercury (MeHg) to total mercury (THg) in water. Our findings highlight substantial interaction between microbial community and compositional variabilities of DOM in proglacial lake. It underlines the essentiality of integrating these factors into future risk appraisals of aquatic ecosystems in proglacial lakes in the context of global climate changes.
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Affiliation(s)
- Guangli Mu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Meiqi Huang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Hongyang Cui
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; School of Ecology and Environment, Tibet University, Lhasa 850000, China; Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau, Ministry of Education, Tibet University, Lhasa 850000, China
| | - Qing Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xiaodong Li
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Xiaoyu Cui
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; School of Ecology and Environment, Tibet University, Lhasa 850000, China; Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau, Ministry of Education, Tibet University, Lhasa 850000, China.
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2
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Hou J, Li J, Liu D, Yu H, Gao H, Wu F. Advancing fluorescence tracing with 3D-2D spectral conversion: A mixed culture on microbial degradation mechanisms of DOM from a large-scale watershed. ENVIRONMENTAL RESEARCH 2024; 262:119877. [PMID: 39216741 DOI: 10.1016/j.envres.2024.119877] [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: 06/12/2024] [Revised: 08/26/2024] [Accepted: 08/27/2024] [Indexed: 09/04/2024]
Abstract
Fluorescence tracing, known for its precision, rapid application, and cost-effectiveness, faces challenges due to the microbial degradation of dissolved organic matter (DOM) in aquatic environments, altering its original spectral fingerprint. This study conducted a 15-day microcosm experiment to examine the effects of biodegradation on the spectral properties of DOM from various sources: livestock excrement (EXC), urban sewage (URB), industrial wastewater (IND), and riparian topsoil (tDOM). Our findings show that while the spectral structures of DOM from different sources change during 15 days of microbial degradation, these changes do not overlap or interfere with each other. However, distinguishing between tDOM and URB in the presence of both IND and EXC is only possible at high resolution. Spectral index calculations revealed significant fluctuations and interference in FI and BIX indices among samples from different sources due to microbial degradation. In contrast, the HIX index exhibited independent fluctuations and remained a reliable spectral index for tracing. LEfSe (Linear discriminant analysis Effect Size) identified characteristic bio-indicators (CBI) for each DOM source. The CBI for tDOM and URB differed significantly; tDOM showed a marked CBI only within the first four days of microbial degradation, with a sharp decline in abundance thereafter, while URB's CBI remained abundant for 12 days. Similarly, IND's CBI maintained high relative abundance for the first 12 days. EXC's CBI was unique, showing a distinct and stable community only after six days of degradation, likely due to its high bioavailability and initial rapid microbial utilization. This study addresses the temporal variability in spectral tracing techniques caused by pollutant biodegradation. We developed a combined spectral-biological tracing technique using the "three-dimensional to two-dimensional" method along with bio-indicators, enhancing the accuracy and timeliness of spectral tracing.
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Affiliation(s)
- Junwen Hou
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Jiancheng Li
- State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Dongping Liu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Huibin Yu
- State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Hongjie Gao
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| | - Fengchang Wu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
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3
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Chen ZW, Hua ZL. Characteristics of organic matter driven by Eichhornia crassipes during co-contamination with per(poly)fluoroalkyl substances (PFASs) and microplastics (MPs). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 953:176114. [PMID: 39255929 DOI: 10.1016/j.scitotenv.2024.176114] [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: 05/16/2024] [Revised: 08/12/2024] [Accepted: 09/05/2024] [Indexed: 09/12/2024]
Abstract
Co-contamination with MPs and PFASs has been recorded, particularly in surface-water environments. Floating macrophyte microcosms are an important part of the surface water ecosystem, and dissolved organic matter (DOM) driven by floating macrophytes (FMDDOM) is critical for maintaining material circulation. However, knowledge gaps remain regarding the impact of MPs and PFASs co-pollution on FMDDOM. An greenhouse simulation experiment was conducted in this study to investigate the effects of four PFASs, perfluorooctanoic acid (PFOA), perfluoro-octane-sulfonic acid (PFOS), perfluoro-2-methyl-3-oxahexanoic acid (Gen X), and potassium 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F-53B), on FMDDOM sourced from Eichhornia crassipes (E. crassipes), a typical floating macrophyte, in the presence and absence of polystyrene (PS) MPs. Four PFASs increased FMDDOM release from E. crassipes, leading to a 32.52-77.49 % increase in dissolved organic carbon (DOC) levels. PS MPs further increased this, with results ranging from -21.28 % to 26.49 %. Based on the parallel factor analysis (PARAFAC), FMDDOM was classified into three types of fluorescent components: tryptophan-like, humic-like, and tyrosine-like compounds. Contaminants of MPs and PFASs modified the relative abundance of these three components. Protein secondary structure analysis showed that fluorocarbon bonds tended to accumulate on the α-helix of proteins in FMDDOM. The relative abundance of fluorescent and chromophorous FMDDOMs varied from 0.648 ± 0.044 to 0.964 ± 0.173, indicating that the photochemical structures of the FMDDOM were modified. FMDDOM exhibits decreased humification and increased aromaticity when contaminated with MPs and PFASs, which may be detrimental to the geochemical cycling of carbon. This study offers a theoretical basis for assessing the combined ecological risks of MPs and PFASs in floating macrophyte ecosystems.
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Affiliation(s)
- Zi-Wei Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China
| | - Zu-Lin Hua
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Nanjing 210098, PR China.
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4
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Pan Y, Meng L, Wu Y, Zhang S, Wu Z, Zhao C, Yang G, Xu J, Ren Y, Huang T, Bian Z, Jiang Q, Zhou J, Yang H, Yu Z, Yuan L, Liu H, Huang C. Molecular composition limits the reaction kinetics of riverine dissolved organic matter decomposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175454. [PMID: 39134281 DOI: 10.1016/j.scitotenv.2024.175454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 08/07/2024] [Accepted: 08/09/2024] [Indexed: 08/16/2024]
Abstract
The bioavailability and degradation of riverine dissolved organic matter (DOM) play crucial roles in greenhouse gas emissions; however, studies on the kinetic decomposition of fluvial DOM remain scarce. In this study, the decomposition kinetics of dissolved organic carbon (DOC) were characterized using the reactivity continuum model through 28-day bio-incubation experiments with water samples from the Yangtze River. The relationship between DOM composition and decomposition kinetics was analyzed using optical and molecular characterization combined with apparent decay coefficients. Our results revealed that DOM compounds rich in nitrogen and sulfur were predominantly removed, exhibiting a transition from an unsaturated to a saturated state following microbial degradation. These heteroatomic compounds, which constituted 75.61 % of the DOM compounds positively correlated with the decay coefficient k0, underwent preferential degradation in the early stages of bio-incubation due to their higher bioavailability. Additionally, we observed that S-containing fractions with high molecular weight values (MW > 400 Da) may be associated with larger reactivity grades. This study underscored the complex interplay between DOM composition and its kinetic decomposition in river ecosystems, providing further support for the significance of molecular composition in large river DOM as crucial factors affecting decomposition.
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Affiliation(s)
- Yiru Pan
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Lize Meng
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - You Wu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Shenyan Zhang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Zijun Wu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Chu Zhao
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Guangrui Yang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Jingyang Xu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Yue Ren
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Tao Huang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Zihao Bian
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China.
| | - Qihao Jiang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Jian Zhou
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Hao Yang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China
| | - Zhaoyuan Yu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China; Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Ministry of Education, Nanjing 210023, China
| | - Linwang Yuan
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China; Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Ministry of Education, Nanjing 210023, China
| | - Hailong Liu
- College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Changchun Huang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; School of Geography Science, Nanjing Normal University, Nanjing 210023, China; Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Ministry of Education, Nanjing 210023, China.
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5
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Liu Y, Li M, Ren D, Li Y. Spatial distribution of sediment dissolved organic matter in oligotrophic lakes and its binding characteristics with Pb(II) and Cu(II). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:43369-43380. [PMID: 38902445 DOI: 10.1007/s11356-024-34043-w] [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: 03/21/2024] [Accepted: 06/16/2024] [Indexed: 06/22/2024]
Abstract
Dissolved organic matter (DOM), the most active component in interstitial waters, determines the stability of heavy metals and secondary release in sediments. However, little is known about the composition and metal-binding patterns of DOM in interstitial water from oligotrophic lakes affected by different anthropogenic perturbations. Here, 18 interstitial water samples were prepared from sediments in agricultural, residential, tourist, and forest regions in an oligotrophic lake (Shengzhong Lake in Sichuan Province, China) watershed. Interstitial water quality and DOM composition, properties, and Cu(II)- and Pb(II)-binding characteristics were measured via physicochemical analysis, UV-vis spectroscopic, fluorescence excitation-emission matrix-parallel factor analysis (EEM-PARAFAC), and fluorescence titration methods. The DOM, which was produced mainly by microbial activities, had low molecular weights, humification degrees, and aromaticity. Based on EEM-PARAFAC results, the DOM was generally composed of tryptophan- (57.7%), terrestrial humic- (18.7%), microbial humic- (15.6%), and tyrosine-like (8.0%) substances. The DOM in the metal complexes was primarily composed of tryptophan-like substances, which accounted for ~42.6% of the DOM-Cu(II) complexes and ~72.0% of the DOM-Pb(II) complexes; however, microbial humic-like substances primarily contributed to the stability of DOM-Cu(II) (logKCu = 3.7-4.6) and DOM-Pb(II) (logKPb = 4.3-4.8). Water quality parameters did not significantly affect the stability of DOM-metal complexes. We demonstrated that the metal-binding patterns of DOM in interstitial water from oligotrophic lakes are highly dependent on microbial DOM composition and are affected by anthropogenic perturbations to a lesser extent.
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Affiliation(s)
- Yanmei Liu
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Mengyuan Li
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Dong Ren
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
- Nanchong Key Laboratory of Eco-Environmental Protection and Pollution Prevention in Jialing River Basin, Nanchong, 637000, China
| | - Yunxiang Li
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China.
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Li Z, Wu Z, Bo S, Chi J, Cui X, He W, Cui X, Liu Y, Zhao Y, Tong Y. Role of low-proportion, hydrophobic dissolved organic matter components in inhibiting methylmercury uptake by phytoplankton. CHEMOSPHERE 2024; 358:142104. [PMID: 38653399 DOI: 10.1016/j.chemosphere.2024.142104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/19/2024] [Accepted: 04/20/2024] [Indexed: 04/25/2024]
Abstract
Uptake of methylmercury (MeHg), a potent neurotoxin, by phytoplankton is a major concern due to its role as the primary pathway for MeHg entry into aquatic food webs, thereby posing a significant risk to human health. While it is widely believed that the MeHg uptake by plankton is negatively correlated with the concentrations of dissolved organic matter (DOM) in the water, ongoing debates continue regarding the specific components of DOM that exerts the dominant influence on this process. In this study, we employed a widely-used resin fractionation approach to separate and classify DOM derived from algae (AOM) and natural rivers (NOM) into distinct components: strongly hydrophobic, weakly hydrophobic, and hydrophilic fractions. We conduct a comparative analysis of different DOM components using a combination of spectroscopy and mass spectrometry techniques, aiming to identify their impact on MeHg uptake by Microcystis elabens, a prevalent alga in freshwater environments. We found that the hydrophobic components had exhibited more pronounced spectral characteristics associated with the protein structures while protein-like compounds between hydrophobic and hydrophilic components displayed significant variations in both distributions and the values of m/z (mass-to-charge ratio) of the molecules. Regardless of DOM sources, the low-proportion hydrophobic components usually dominated inhibition of MeHg uptake by Microcystis elabens. Results inferred from the correlation analysis suggest that the uptake of MeHg by the phytoplankton was most strongly and negatively correlated with the presence of protein-like components. Our findings underscore the importance of considering the diverse impacts of different DOM fractions on inhibition of phytoplankton MeHg uptake. This information should be considered in future assessments and modeling endeavors aimed at understanding and predicting risks associated with aquatic Hg contamination.
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Affiliation(s)
- Zhike Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; School of Resources and Environment, Southwest University of Science and Technology, Mianyang, 621000, China
| | - Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Shao Bo
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Jie Chi
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Xiaoyu Cui
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Wei He
- School of Water Resources and Environment, China University of Geosciences, Beijing, 100083, China
| | - Xiaomei Cui
- Key Laboratory of Biodiversity and Eco-Environmental Protection of the Qinghai-Tibetan Plateau (Ministry of Education), School of Ecology and Environment, Tibet University, Lhasa, 850000, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; Key Laboratory of Biodiversity and Eco-Environmental Protection of the Qinghai-Tibetan Plateau (Ministry of Education), School of Ecology and Environment, Tibet University, Lhasa, 850000, China.
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Yang Y, Tang X, Hu H, Zhan X, Zhang X, Zhang X. Molecular insight into the binding properties of marine algogenic dissolved organic matter for polybrominated diphenyl ethers and their combined effect on marine zooplankton. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171131. [PMID: 38387578 DOI: 10.1016/j.scitotenv.2024.171131] [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: 12/04/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Polybrominated diphenyl ethers (PBDEs) are widespread in marine ecosystems, despite the limits placed on several congeners, and pose a threat to marine organisms. Many coexisting factors, especially dissolved organic matter (DOM), affect the environmental behavior and ecological risk of PBDEs. Since blooms frequently occur in coastal waters, we used algogenic DOM (A-DOM) from the diatom Skeletonem costatum and examined the interaction of A-DOM with 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). Moreover, their combined effect on the rotifer Brachionus plicatilis was analyzed. During the stationary period, A-DOM had more proteins than polysaccharides, and 7 extracellular proteins were identified. A-DOM fluorescence was statically quenched by BDE-47, and amide, carbonyl, and hydroxyl groups in A-DOM were involved. Molecular docking analysis showed that all 5 selected proteins of A-DOM could spontaneously bind with BDE-47 and that hydrophobic interactions, van der Waals forces and pi-bond interactions existed. The reproductive damage, oxidative stress and inhibition of mitochondrial activity induced by BDE-47 in rotifers were relieved by A-DOM addition. Transcriptomic analysis further showed that A-DOM could activate energy metabolic pathways in rotifers and upregulate genes encoding metabolic detoxification proteins and DNA repair. Moreover, A-DOM alleviated the interference effect of BDE-47 on lysosomes, the extracellular matrix pathway and the calcium signaling system. Alcian blue staining and scanning electron microscopy showed that A-DOM aggregates were mainly stuck to the corona and cuticular surface of the rotifers; this mechanism, rather than a real increase in uptake, was the reason for enhanced bioconcentration. This study reveals the complex role of marine A-DOM in PBDEs bioavailability and enhances the knowledge related to risk assessments of PBDE-like contaminants in marine environments.
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Affiliation(s)
- Yingying Yang
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao 266003, China
| | - Xuexi Tang
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Hanwen Hu
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao 266003, China
| | - Xiaotong Zhan
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao 266003, China
| | - Xin Zhang
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao 266003, China
| | - Xinxin Zhang
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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8
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Fan T, Yao X, Sang D, Liu L, Sun Z, Deng H, Zhang Y, Sun X. Composition characteristics and metal binding behavior of macrophyte-derived DOM (MDOM) under microbial combined photodegradation: A state closer to actual macrophytic lakes. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133124. [PMID: 38142658 DOI: 10.1016/j.jhazmat.2023.133124] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/03/2023] [Accepted: 11/27/2023] [Indexed: 12/26/2023]
Abstract
In actual lakes, the "unstable components" of macrophyte-derived DOM (MDOM) are always degraded and cannot exist abidingly, but the environmental impact brought by it is ignored. In this study, MDOM from Potamogeton crispus was extracted to carry out microbial combined photodegradation (M-Photodegradation) and fluorescence titration experiments. Then the traits and metal binding reaction of MDOM under M-Photodegradation were analysed and compared with the features of lake-derived DOM (LDOM) from point monitoring of Dongping Lake through EEM-PARAFAC, 2D-SF-COS, and 2D-FTIR-COS. The results showed that the features of MDOM after M-Photodegradation were closer to those of LDOM. The degradation amplitudes were 93.53% ± 0.53% for C4 in microbial degradation and 78.31% ± 0.74% for C3 in photodegradation. Correspondingly, both were hardly detected in LDOM. Protein-like substances and aliphatic C-OH were preferentially selected by Cu2+, while humic-like matter and phenolic hydroxyl O-H responded faster to Pb2+. Although the binding sequences remained unchanged after M-Photodegradation, the LogKCu and LogKPb of components decreased overall, indicating increased environmental risks. This study proves that the refractory MDOM retained after degradation was more consistent with the actual state of macrophytic lakes and provides more information for the treatment of heavy metal pollution in lakes.
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Affiliation(s)
- Tuantuan Fan
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China; College of Water Sciences, Beijing Normal University, Beijing 100875, China
| | - Xin Yao
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China.
| | - Dongling Sang
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China
| | - Li Liu
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China
| | - Zhaoli Sun
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China
| | - Huanguang Deng
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China
| | - Yinghao Zhang
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China
| | - Xiao Sun
- School of Geography and Environment, Liaocheng University, Liaocheng 252000, China
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9
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Wu Z, Li Z, Shao B, Chen J, Cui X, Cui X, Liu X, Zhao YX, Pu Q, Liu J, He W, Liu Y, Liu Y, Wang X, Meng B, Tong Y. Differential response of Hg-methylating and MeHg-demethylating microbiomes to dissolved organic matter components in eutrophic lake water. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133298. [PMID: 38141310 DOI: 10.1016/j.jhazmat.2023.133298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/01/2023] [Accepted: 12/15/2023] [Indexed: 12/25/2023]
Abstract
Methylmercury (MeHg) production in aquatic ecosystems is a global concern because of its neurotoxic effect. Dissolved organic matter (DOM) plays a crucial role in biogeochemical cycling of Hg. However, owing to its complex composition, the effects of DOM on net MeHg production have not been fully understood. Here, the Hg isotope tracer technique combined with different DOM treatments was employed to explore the influences of DOM with divergent compositions on Hg methylation/demethylation and its microbial mechanisms in eutrophic lake waters. Our results showed that algae-derived DOM treatments enhanced MeHg concentrations by 1.42-1.53 times compared with terrestrial-derived DOM. Algae-derived DOM had largely increased the methylation rate constants by approximately 1-2 orders of magnitude compared to terrestrial-derived DOM, but its effects on demethylation rate constants were less pronounced, resulting in the enhancement of net MeHg formation. The abundance of hgcA and merB genes suggested that Hg-methylating and MeHg-demethylating microbiomes responded differently to DOM treatments. Specific DOM components (e.g., aromatic proteins and soluble microbial byproducts) were positively correlated with both methylation rate constants and the abundance of Hg-methylating microbiomes. Our results highlight that the DOM composition influences the Hg methylation and MeHg demethylation differently and should be incorporated into future Hg risk assessments in aquatic ecosystems.
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Affiliation(s)
- Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zhike Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bo Shao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Ji Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xiaomei Cui
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Xiaoyu Cui
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xianhua Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Ying Xin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Qiang Pu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jiang Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei He
- School of Water Resource and Environment, China University of Geoscience (Beijing), Beijing 100083, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yurong Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xuejun Wang
- College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; School of Ecology and Environment, Tibet University, Lhasa 850000, China.
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10
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Yang Q, Huang L, Yang N, Cui H, Zhao Y, Li Z, Tong Y. Transgenerational effects of extracts containing Microcystin-LR exposure on reproductive toxicity and offspring growth inhibition in a model organism zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 268:106860. [PMID: 38354462 DOI: 10.1016/j.aquatox.2024.106860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/29/2024] [Accepted: 02/03/2024] [Indexed: 02/16/2024]
Abstract
Cyanobacteria cell lysates release numerous toxic substances (e.g., cyanotoxins) into the water, posing a serious threat to human health and aquatic ecosystems. Microcystins (MCs) are among the most abundant cyanotoxins in the cell lysates, with microcystin-LR (MC-LR) being one of the most common and highly toxic congeners. In this study, zebrafish (Danio rerio) were exposed to different levels MC-LR that from extracts of Microcystis aeruginosa. Changes in the MC-LR accumulations, organ coefficients, and antioxidant enzyme activities in the zebrafish were analyzed. Transgenerational reproductive toxicity of MC-LR in the maternal and paternal generations was further investigated, as well as the influences of extracts containing MC-LR exposures of the F1 on the growth of zebrafish. The study found that high levels of MC-LR could be detected in the major organs of adult zebrafish, particularly in spleen. Notably, concentration of MC-LR in the spermary was significantly higher than that in the ovarium. MC-LR could induce oxidative damage by affecting the activities of catalase and superoxide dismutase. Inherited from F0, MC-LR led to impaired development in the F1 generation. Difference in offspring survival rates could be observed in the groups with different MC-LR levels of maternal and paternal exposures. This study reveals transgenerational effects of MC-LR on the reproductive toxicity and offspring growth inhibition to the aquatic organisms, which should be emphasized in the future ecological risk assessment.
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Affiliation(s)
- Qing Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300000, China; School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Lanlan Huang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300000, China
| | - Ning Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300000, China
| | - Hongyang Cui
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300000, China
| | - Yanbin Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zipeng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300000, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300000, China; School of Ecology and Environment, Tibet University, Lhasa 850000, China.
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11
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Yang L, Chen L, Zhuang WE, Zhu Z. Unveiling changes in the complexation of dissolved organic matter with Pb(II) by photochemical and microbial degradation using fluorescence EEMs-PARAFAC. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122982. [PMID: 37984478 DOI: 10.1016/j.envpol.2023.122982] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 11/22/2023]
Abstract
Dissolved organic matter (DOM) is very important in determining the speciation, behaviors, and risk of metal pollutants in aquatic ecosystems. Photochemical and microbial degradation are key processes in the cycling of DOM, yet their effects on the DOM-Pb(II) interaction remain largely unknown. This was studied by examining the complexation of river DOM with Pb(II) after degradation, using fluorescence quenching titration and excitation-emission matrices-parallel factor analysis (EEMs-PARAFAC). Three humic-like and two protein-like components were identified, with strong removals of humic-like components and decreasing average molecular weight and humification degree of DOM by photo- and photo-microbial degradation. The changes in humic-like abundance and structure resulted in notable weakening of their interaction with Pb(II). The tryptophan-like C2 was also mainly removed by photo-degradation, while the tyrosine-like C3 could be either removed or accumulated. The Pb(II)-binding of protein-like components was generally weaker but was enhanced in some degradation groups, which might be related to the lowering competition from humic-like components. The binding parameters correlated significantly with the DOM indices, which were dominated by photo-degradation for humic-like components but by seasonal variations for the tyrosine-like component. These results have implications for understanding the key mechanisms underlying the variability of the DOM-metal interaction in aquatic environments.
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Affiliation(s)
- Liyang Yang
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou, Fujian, PR China.
| | - Linwei Chen
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou, Fujian, PR China
| | - Wan-E Zhuang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, PR China
| | - Zhuoyi Zhu
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, PR China
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12
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Armstrong G, Janssen SE, Poulin BA, Tate MT, Krabbenhoft DP, Hurley JP. Competition between Dissolved Organic Matter and Freshwater Plankton Control Methylmercury Isotope Fractionation during Uptake and Photochemical Demethylation. ACS EARTH & SPACE CHEMISTRY 2023; 7:2382-2392. [PMID: 38148993 PMCID: PMC10749477 DOI: 10.1021/acsearthspacechem.3c00154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/28/2023]
Abstract
Isotope fractionation related to photochemical reactions and planktonic uptake at the base of the food web is a major uncertainty in the biological application of mercury (Hg) stable isotopes. In freshwater systems, it is unclear how competitive interactions among methylmercury (MeHg), dissolved organic matter (DOM), and phytoplankton govern the magnitude of mass-dependent and mass-independent fractionation. This study investigated how DOM alters rates of planktonic MeHg uptake and photodegradation and corresponding Hg isotope fractionation in the presence of freshwater phytoplankton species, Raphidocelis subcapitata. Outdoor sunlight exposure experiments utilizing R. subcapitata were performed in the presence of different DOM samples using environmentally relevant ratios of MeHg-DOM thiol groups. The extent of Δ199Hg in phytoplankton incubations (2.99‰ St. Louis River HPOA, 1.88‰ Lake Erie HPOA) was lower compared to paired abiotic control experiments (4.29 and 2.86‰, respectively) after ∼30 h of irradiation, resulting from cell shading or other limiting factors reducing the extent of photodemethylation. Although the Δ199Hg/Δ201Hg ratio was uniform across experiments (∼1.4), Δ199Hg/δ202Hg slopes varied dramatically (from -0.96 to 15.4) across incubations with R. subcapitata and DOM. In addition, no evidence of Hg isotope fractionation was observed within R. subcapitata cells. This study provides a refined examination of Hg isotope fractionation markers for key processes occurring in the lower food web prior to bioaccumulation, critical for accurately accounting for the photochemical processing of Hg isotopes across a wide spectrum of freshwater systems.
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Affiliation(s)
- Grace
J. Armstrong
- U.S.
Geological Survey Upper Midwest Water Science Center, Madison, Wisconsin 53726, United States
- Environmental
Chemistry and Technology Program, University
of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Sarah E. Janssen
- U.S.
Geological Survey Upper Midwest Water Science Center, Madison, Wisconsin 53726, United States
| | - Brett A. Poulin
- Department
of Environmental Toxicology, University
of California Davis, Davis, California 95616 United States
| | - Michael T. Tate
- U.S.
Geological Survey Upper Midwest Water Science Center, Madison, Wisconsin 53726, United States
| | - David P. Krabbenhoft
- U.S.
Geological Survey Upper Midwest Water Science Center, Madison, Wisconsin 53726, United States
| | - James P. Hurley
- Environmental
Chemistry and Technology Program, University
of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- University
of Wisconsin Aquatic Sciences Center, Madison, Wisconsin 53706, United States
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