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Gong X, He M, Hao Z, Zhao R, Liu J. Freeze-induced acceleration of iodide oxidation and consequent iodination of dissolved organic matter to form organoiodine compounds. J Environ Sci (China) 2024; 144:67-75. [PMID: 38802239 DOI: 10.1016/j.jes.2023.12.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 12/25/2023] [Accepted: 12/25/2023] [Indexed: 05/29/2024]
Abstract
Freeze-induced acceleration of I- oxidation and the consequent iodination of dissolved organic matter (DOM) contribute to the formation of organoiodine compounds (OICs) in cold regions. The formed OICs may be a potentially important source of risk and are very closely with the environment and human health. Herein, we investigated the acceleration effects of the freeze process on I- oxidation and the formation of OICs. In comparison to reactive iodine species (RIS) formed in aqueous solutions, I- oxidation and RIS formation were greatly enhanced in frozen solution and were affected by pH, and the content of I- and O2. Freeze-thaw process further promoted I- oxidation and the concentration of RIS reached 45.7 µmol/L after 6 freeze-thaw cycles. The consequent products of DOM iodination were greatly promoted in terms of both concentration and number. The total content of OICs ranged from 0.02 to 2.83 µmol/L under various conditions. About 183-1197 OICs were detected by Fourier transform ion cyclotron resonance mass spectrometry, and more than 96.2% contained one or two iodine atoms. Most OICs had aromatic structures and were formed via substitution and addition reactions. Our findings reveal an important formation pathway for OICs and shed light on the biogeochemical cycling of iodine in the natural aquatic environment.
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Affiliation(s)
- Xuexin Gong
- School of Resources and Environment, Yangtze University, Wuhan 430100, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Mei He
- School of Resources and Environment, Yangtze University, Wuhan 430100, China
| | - Zhineng Hao
- School of Resources and Environment, Yangtze University, Wuhan 430100, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Rusong Zhao
- Qilu University of Technology (Shandong Academy of Sciences), Shandong Analysis and Test Center, Key Laboratory for Applied Technology of Sophisticated Analytical Instruments of Shandong Province, Jinan 250014, China
| | - Jingfu Liu
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China.
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2
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Chen L, Cheng G, Zhou Z, Liang Y, Ci Z, Yin Y, Liu G, Cai Y, Li Y. Methylmercury cycling in the Bohai Sea and Yellow Sea: Reasons for the low system efficiency of methylmercury production. WATER RESEARCH 2024; 258:121792. [PMID: 38772318 DOI: 10.1016/j.watres.2024.121792] [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: 01/08/2024] [Revised: 05/08/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024]
Abstract
Coastal seas contribute the majority of human methylmercury (MeHg) exposure via marine fisheries. The terrestrial area surrounding the Bohai Sea and Yellow Sea (BS and YS) is one of the mercury (Hg) emission "hot spots" in the world, resulting in high concentrations of Hg in BS and YS seawater in comparison to other marine systems. However, comparable or even lower Hg levels were detected in seafood from the BS and YS than other coastal regions around the word, suggesting a low system bioaccumulation of Hg. Reasoning a low system efficiency of MeHg production (represented by MeHg/THg (total Hg) in seawater) may be present in these two systems, seven cruises were conducted in the BS and YS to test this hypothesis. MeHg/THg ratios in BS and YS seawater were found to be lower than that in most coastal systems, indicating that the system efficiency of MeHg production is relatively lower in the BS and YS. The low system efficiency of MeHg production reduces the risk of Hg in the BS and YS with high Hg discharge intensity. By measuring in situ production and degradation of MeHg using double stable isotope addition method, and MeHg discharge flux from various sources and its exchange at various interfaces, the budgets of MeHg in the BS and YS were estimated. The results indicate that in situ methylation and demethylation are the major source and sink of MeHg in the BS and YS. By comparing the potential controlling processes and environmental parameters for MeHg/THg in the BS and YS with the other coastal seas, estuaries and bays, lower transport efficiency of inorganic Hg from water column to the sediment, slower methylation of Hg, and rapid demethylation of MeHg were identified to be major reasons for the low system efficiency of MeHg production in the BS and YS. This study highlights the necessity of monitoring the system efficiency of MeHg production, associated processes, and controlling parameters to evaluate the efficiency of reducing Hg emissions in China as well as the other countries.
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Affiliation(s)
- Lufeng Chen
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, PR China
| | - Guoyi Cheng
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, PR China
| | - Zhengwen Zhou
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, PR China
| | - Yong Liang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, PR China
| | - Zhijia Ci
- School of Marine Sciences, Sun Yat-Sen University, Guangzhou, 519082, PR China
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect and State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
| | - Yong Cai
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL, 33199, USA
| | - Yanbin Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, PR China.
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3
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Wang YL, Ikuma K, Brown AMV, Deonarine A. Global survey of hgcA-carrying genomes in marine and freshwater sediments: Insights into mercury methylation processes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 352:124117. [PMID: 38714231 DOI: 10.1016/j.envpol.2024.124117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/11/2024] [Accepted: 05/05/2024] [Indexed: 05/09/2024]
Abstract
Mercury (Hg) methylation is a microbially mediated process that produces methylmercury (MeHg), a bioaccumulative neurotoxin. A highly conserved gene pair, hgcAB, is required for Hg methylation, which provides a basis for identifying Hg methylators and evaluating their genomic composition. In this study, we conducted a large-scale omics analysis in which 281 metagenomic freshwater and marine sediment samples from 46 geographic locations across the globe were queried. Specific objectives were to examine the prevalence of Hg methylators, to identify horizontal gene transfer (HGT) events involving hgcAB within Hg methylator communities, and to identify associations between hgcAB and microbial biochemical functions/genes. Hg methylators from the phyla Desulfobacterota and Bacteroidota were dominant in both freshwater and marine sediments while Firmicutes and methanogens belonging to Euryarchaeota were identified only in freshwater sediments. Novel Hg methylators were found in the Phycisphaerae and Planctomycetia classes within the phylum Planctomycetota, including potential hgcA-carrying anammox metagenome-assembled genomes (MAGs) from Candidatus Brocadiia. HGT of hgcA and hgcB were identified in both freshwater and marine methylator communities. Spearman's correlation analysis of methylator genomes suggested that in addition to sulfide, thiosulfate, sulfite, and ammonia may be important parameters for Hg methylation processes in sediments. Overall, our results indicated that the biochemical drivers of Hg methylation vary between marine and freshwater sites, lending insight into the influence of environmental perturbances, such as a changing climate, on Hg methylation processes.
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Affiliation(s)
- Yong-Li Wang
- Department of Civil, Environmental & Construction Engineering, Texas Tech University, Lubbock, TX, United States
| | - Kaoru Ikuma
- Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA, United States
| | - Amanda M V Brown
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, United States
| | - Amrika Deonarine
- Department of Civil, Environmental & Construction Engineering, Texas Tech University, Lubbock, TX, United States.
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4
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Wu D, Chen L, Zong X, Jiang F, Wang X, Xu M, Ai F, Du W, Yin Y, Guo H. Elevated CO 2 exacerbates the risk of methylmercury exposure in consuming aquatic products: Evidence from a complex paddy wetland ecosystem. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 352:124095. [PMID: 38703984 DOI: 10.1016/j.envpol.2024.124095] [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: 01/20/2024] [Revised: 04/08/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Elevated CO2 levels and methylmercury (MeHg) pollution are important environmental issues faced across the globe. However, the impact of elevated CO2 on MeHg production and its biological utilization remains to be fully understood, particularly in realistic complex systems with biotic interactions. Here, a complete paddy wetland microcosm, namely, the rice-fish-snail co-culture system, was constructed to investigate the impacts of elevated CO2 (600 ppm) on MeHg formation, bioaccumulation, and possible health risks, in multiple environmental and biological media. The results revealed that elevated CO2 significantly increased MeHg concentrations in the overlying water, periphyton, snails and fish, by 135.5%, 66.9%, 45.5%, and 52.1%, respectively. A high MeHg concentration in periphyton, the main diet of snails and fish, was the key factor influencing the enhanced MeHg in aquatic products. Furthermore, elevated CO2 alleviated the carbon limitation in the overlying water and proliferated green algae, with subsequent changes in physico-chemical properties and nutrient concentrations in the overlying water. More algal-derived organic matter promoted an enriched abundance of Archaea-hgcA and Deltaproteobacteria-hgcA genes. This consequently increased the MeHg in the overlying water and food chain. However, MeHg concentrations in rice and soil did not increase under elevated CO2, nor did hgcA gene abundance in soil. The results reveal that elevated CO2 exacerbated the risk of MeHg intake from aquatic products in paddy wetland, indicating an intensified MeHg threat under future elevated CO2 levels.
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Affiliation(s)
- Danni Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Lei Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China; School of Civil Engineering, University of Leeds, Leeds, LS2 9JT, UK
| | - Xueying Zong
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Fan Jiang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Xiaojie Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Meiling Xu
- College of Environmental Science and Engineering, Yangzhou University, Yangzhou, 225127, China
| | - Fuxun Ai
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Wenchao Du
- School of Environment, Nanjing Normal University, Nanjing, 210023, China
| | - Ying Yin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Hongyan Guo
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China; Joint International Research Centre for Critical Zone Science-University of Leeds and Nanjing University, Nanjing University, Nanjing, 210023, China; Quanzhou Institute for Environmental Protection Industry, Nanjing University, Quanzhou, 362046, China.
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5
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Wang Y, Zhang L, Chen X, Li C, Ding S, Yan J, Xiao J, Wang B, Xu L, Hang X. Algal-derived dissolved organic matter accelerates mercury methylation under cyanobacterial blooms in the sediment of eutrophic lakes. ENVIRONMENTAL RESEARCH 2024; 251:118734. [PMID: 38493854 DOI: 10.1016/j.envres.2024.118734] [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: 01/01/2024] [Revised: 02/17/2024] [Accepted: 03/14/2024] [Indexed: 03/19/2024]
Abstract
Mercury (Hg), especially in the form of methylmercury (MeHg), poses a significant threat to both organisms and the environment due to its extreme toxicity. While methylation process of Hg in sediments has been extensively studied, recognition of its associated risks and mechanisms during cyanobacterial blooms remains limited. This study investigated the distribution characteristics of Hg and MeHg in sediments of Taihu Lake, China. The concentration of Hg and MeHg varied within the range of 96.0-212.0 ng g-1 and 0.1-0.5 ng g-1, respectively. Higher ecological risks of Hg were found in algal-dominated regions compared to macrophyte areas. The significant correlations observed between Hg, MeHg, and algal-derived dissolved organic matter (ADOM) components C1 and C2 in algal-dominated regions indicate a close association between ADOM components and the Hg methylation process. These components are involved in the absorption or complexation of Hg, participate in redox reactions, and modulate microbial activity. The dsrB gene in sulfate-reducing bacteria (SRB) was found to accelerate the metabolic pathways of Hg methylation. These findings indicate that ADOM could enhance the methylation process of Hg during cyanobacterial blooms, which warrants attention.
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Affiliation(s)
- Yan Wang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Lan Zhang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Xiang Chen
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Cai Li
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Shiming Ding
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Jiabao Yan
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Jing Xiao
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Bin Wang
- Zhongyifeng Construction Group Co., Ltd., Suzhou, 215131, China
| | - Lv Xu
- Anhui Urban Construction Design Institute Corp., Ltd, Hefei, 230051, China
| | - Xiaoshuai Hang
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China.
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6
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Zhong H, Su Y, Wu X, Nunes L, Li C, Hao Y, Liu YR, Tang W. Mercury supply limits methylmercury production in paddy soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172335. [PMID: 38604369 DOI: 10.1016/j.scitotenv.2024.172335] [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: 01/22/2024] [Revised: 03/18/2024] [Accepted: 04/07/2024] [Indexed: 04/13/2024]
Abstract
The neurotoxic methylmercury (MeHg) is a product of inorganic mercury (IHg) after microbial transformation. Yet it remains unclear whether microbial activity or IHg supply dominates Hg methylation in paddies, hotspots of MeHg formation. Here, we quantified the response of MeHg production to changes in microbial activity and Hg supply using 63 paddy soils under the common scenario of straw amendment, a globally prevalent agricultural practice. We demonstrate that the IHg supply is the limiting factor for Hg methylation in paddies. This is because IHg supply is generally low in soils and can largely be facilitated (by 336-747 %) by straw amendment. The generally high activities of sulfate-reducing bacteria (SRB) do not limit Hg methylation, even though SRB have been validated as the predominant microbial Hg methylators in paddies in this study. These findings caution against the mobilization of legacy Hg triggered by human activities and climate change, resulting in increased MeHg production and the subsequent flux of this potent neurotoxin to our dining tables.
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Affiliation(s)
- Huan Zhong
- School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China
| | - Yao Su
- School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China
| | - Xinda Wu
- School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China
| | - Luís Nunes
- Faculty of Sciences and Technology, Civil Engineering Research and Innovation for Sustainability Center, University of Algarve, Faro, Portugal
| | - Chengjun Li
- Institute of Environmental Research at Greater Bay Area, Guangzhou University, Guangzhou, Guangdong Province, China
| | - Yunyun Hao
- State Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - Yu-Rong Liu
- State Key Laboratory of Agricultural Microbiology and College of Resources and Environment, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - Wenli Tang
- School of Environment, Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, China.
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7
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Yang X, Yu R, Wang T, Wen X, He Y, Li Z, Ma C, Chen W, Zhang C. Algae-leached DOM inhibits the Hg(II) reduction and uptake by lettuce in aquatic environments under light conditions. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 271:106928. [PMID: 38688065 DOI: 10.1016/j.aquatox.2024.106928] [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: 12/26/2023] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/02/2024]
Abstract
The significant role of aquatic phytoplankton in global primary productivity, accounting for approximately 50 % on an annual basis, has been recognized as a crucial factor in the reduction of Hg(II). In this study, we compared the efficiency of Hg(II) photoreduction mediated by three types of algae leaching dissolved organic matter (DOM) and humic acid (DOM-HA). Especially, we investigated the potential effects of algae-leached DOM on the photoreduction of Hg(II) and its subsequent uptake by lettuce, which serves as an indicator of Hg bioavailability for aquatic plants. The results revealed that under light conditions, the conversion of Hg(II) to Hg(0) mediated by algae-leached DOM and DOM-HA was 6.4-39.9 % higher compared to dark condition. Furthermore, the free radical quenching experiment demonstrated that the reduction of Hg(II) mediated by DOM-HA was higher than algae-leached DOM, mainly due to its ability to generate superoxide anion (O2•-). Moreover, the photoreduction efficiences of Hg(II) mediated by algae-leached DOM were 29-18 % lower compared to DOM-HA. The FT-IR analysis revealed that the production of -SH from algae-leached DOM led to the formation of strong metal-complexes, which restricts the reduction process from Hg(II) to Hg(0). Finally, the hydroponics experiment demonstrated that algae-leached DOM inhibited the bioavailability of Hg(II) to plants more effectively than DOM-HA. Our research emphasizes the significant functional roles and potential mechanisms of algae in reducing Hg levels, thereby influencing the availability of Hg in aquatic ecosystems.
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Affiliation(s)
- Xu Yang
- Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010070, China; College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Ruihong Yu
- Inner Mongolia Key Laboratory of River and Lake Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010070, China.
| | - Tantan Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Xin Wen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Yubo He
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Zihao Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Chi Ma
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Wenhao Chen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Chang Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China.
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8
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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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9
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Duan C, Liu F, You J, Yang K, Liu X, Xu H. Influences of dissolved organic matters on the adsorption and bioavailability of sulfadiazine: Molecular weight- and type-dependent heterogeneities. CHEMOSPHERE 2024; 354:141677. [PMID: 38467198 DOI: 10.1016/j.chemosphere.2024.141677] [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: 12/19/2023] [Revised: 02/26/2024] [Accepted: 03/08/2024] [Indexed: 03/13/2024]
Abstract
The bioavailability of contaminants in aquatic environments was highly related with the existing forms (soluble or adsorbed) and properties of dissolved organic matters (DOMs). In this study, the molecular weight (MWs)-dependent effects of DOMs on the adsorption and bioavailability of sulfadiazine were explored. Colloid ZnO and Al2O3 were employed as the representative colloidal particles, and algae-derived organic matter (AOM) and humic acid (HA) were selected as typical autochthonous and allochthonous DOMs. The ultrafiltration procedure was applied to divide the bulk DOMs into high MW (HMW-, 1 kDã0.45 μm) and low MW (LMW-, <1 kDa) fractions. Results showed that HMW-DOM contained more aromatic and protein-like substances as compared to the LMW counterparts. In addition, presence of AOM promoted sulfadiazine adsorption capabilities by 1.19-4.54 folds and mitigated the inhibition ratio by 0.56-0.78 folds, whereas those of HA inhibited sulfadiazine adsorption by 0.27-0.84 folds and enhanced the biotoxicity by 1.21-1.45 folds. Regardless of different DOM types, HMW-fraction exhibited highest effects on sulfadiazine adsorption and bioavailability, followed by the bulk- and LMW-fractions. Two-dimensional correlation spectroscopy showed that sulfadiazine was adsorbed on colloidal surfaces prior to AOM, and the subsequent adsorption of AOM can provide additional sites for sulfadiazine adsorption, which decreased the concentrations of aqueous sulfadiazine as well as the biotoxicity to Microcystis aeruginosa (M. aeruginosa). The HA, however, was preferentially adsorbed on colloidal surfaces, which hindered the subsequent sulfadiazine adsorption and resulted in a high sulfadiazine abundance in aqueous solution as well as the enhanced biotoxicity to M. aeruginosa. This study highlighted the importance of the types and MWs of DOMs in influencing the behaviors and ecological effects of aquatic contaminants.
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Affiliation(s)
- Chongsen Duan
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Fei Liu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Jikang You
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Keli Yang
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China
| | - Xin Liu
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China.
| | - Huacheng Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
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10
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Zhang S, Xia M, Pan Z, Wang J, Yin Y, Lv J, Hu L, Shi J, Jiang T, Wang D. Soil organic matter degradation and methylmercury dynamics in Hg-contaminated soils: Relationships and driving factors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 356:120432. [PMID: 38479282 DOI: 10.1016/j.jenvman.2024.120432] [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: 11/06/2023] [Revised: 02/01/2024] [Accepted: 02/17/2024] [Indexed: 04/07/2024]
Abstract
Biodegradation of soil organic matter (SOM), which involves greenhouse gas (GHG) emissions, plays an essential role in the global carbon cycle. Over the past few decades, this has become an important research focus, particularly in natural ecosystems. SOM biodegradation significantly affects contaminants in the environment, such as mercury (Hg) methylation, producing highly toxic methylmercury (MeHg). However, the potential link between GHG production from SOM turnover in contaminated soils and biogeochemical processes involving contaminants remains unclear. In this study, we investigated the dynamics of GHG, MeHg production, and the relationship between biogeochemical processes in soils from two typical Hg mining sites. The two contaminated soils have different pathways, explaining the significant variations in GHG and MeHg production. The divergence of the microbial communities in these two biogeochemical processes is essential. In addition to the microbial role, abiotic factors such as Hg species can significantly affect MeHg production. On the other hand, we found an inverse relationship between CH4 and MeHg, suggesting that carbon emission reduction policies and management could inadvertently increase the MeHg levels. This highlights the need for an eclectic approach to organic carbon sequestration and contaminant containment. These findings suggest that it is difficult to establish a general pattern to describe and explain the SOM degradation and MeHg production in contaminated soils within the specific scenarios. However, this study provides a case study and helpful insights for further understanding the links between environmental risks and carbon turnover in Hg mining areas.
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Affiliation(s)
- Siqi Zhang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China
| | - Meng Xia
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China
| | - Zhaoyang Pan
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianxu Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, China
| | - Jitao Lv
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Ligang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, China
| | - Jianbo Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, China
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan, 430056, China.
| | - Dingyong Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing, 400716, China
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11
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Wang J, Xie Q, Xiang Y, Xue J, Jiang T, Zhang C, Li J, Wang Y, Wang D. Anthropogenic activities enhance mercury methylation in sediments of a multifunctional lake: Evidence from dissolved organic matter and mercury-methylating microorganisms. JOURNAL OF HAZARDOUS MATERIALS 2024; 466:133505. [PMID: 38280325 DOI: 10.1016/j.jhazmat.2024.133505] [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: 09/11/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 01/29/2024]
Abstract
Multifunctional lakes are highly susceptible to anthropogenic influences, potentially introducing exogenous pollutants or nutrients into aquatic sediments. This, in turn, affects the mercury (Hg) methylation in the sediments. This study was conducted in the Changshou Lake, a representative multifunctional lake in southwestern China, with a specific focus on investigating the Hg variations, the potential of Hg methylation, and the influential factors affecting the methylation process within sediments across different functional areas. The results revealed significant variations in total Hg concentrations between the ecological culture area (area I), the ecological tourism area (area II), and the wetland protection area (area III), suggesting the possibility of exogenous Hg introduction associated with human activities. Furthermore, sediments from areas I and II displayed a greater potential for Hg methylation. This was ascribed to the enhanced diversity and relative abundance of Hg-methylating microorganisms, especially Geobacteraceae, induced by elevated levels of dissolved organic carbon in these two areas from human activities like historical cage culture. This study provides evidence that anthropogenic activities enhance the process of Hg methylation in the sediments of multifunctional lakes, highlighting the necessity of implementing comprehensive scientific water quality management practices to mitigate the negative impacts of human influences on these unique ecosystems.
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Affiliation(s)
- Juan Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qing Xie
- College of Resources and Safety, Chongqing Vocational Institute of Engineering, Chongqing 402260, China
| | - Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Jinping Xue
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et des Physico-Chimie pour l'Environnement et les Matériaux (IPREM), Pau 64000, France
| | - Tao Jiang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Cheng Zhang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Jiajia Li
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China.
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
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12
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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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13
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Lei P, Zhu J, Zhang J, He H, Chen M, Zhong H. Algal organic matter inhibits methylmercury photodegradation in eutrophic lake water: A dynamic study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165661. [PMID: 37474073 DOI: 10.1016/j.scitotenv.2023.165661] [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: 06/19/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Algal organic matter (AOM) is a major component of dissolved organic matter (DOM) in eutrophic lakes and could impact the photodegradation of neurotoxic methylmercury (MeHg) in water. Predicting these effects, however, is challenging, largely due to the dynamic changes of AOM during algal decomposition. Here, we investigated the effects of AOM on MeHg photodegradation throughout the algal decomposition process and elucidated these effects by characterizing dynamic changes of AOM and exploring the respective roles of various reactive oxygen species (ROS). Our results reveal that AOM derived from algal decomposition significantly inhibits MeHg photodegradation, and the extent of this inhibition varies depending on the specific lakes (8-21 %, p < 0.05) and their eutrophication states (16-28 %, p < 0.05). The inhibitory effect gradually weakened as the decomposition progressed, which may be attributed to the dynamic changes in the quantity and quality of AOM. Moreover, hydroxyl radical (·OH) was found to be the main contributor in driving MeHg photodegradation (15-23 %) during the early stages of decomposition (day 0-3), while in the later stage (day 12-24), the role of singlet oxygen (1O2, 15-20 %) and (3DOM*, 21-30 %) gradually strengthened and these three ROS jointly drove MeHg photodegradation. Based on our findings and recent studies, we propose that AOM derived from algal decomposition plays a vital role in increasing the risk of MeHg in eutrophic lakes. It promotes MeHg formation while simultaneously inhibiting its photodegradation. Integrating AOM-MeHg interactions into Hg biogeochemical cycling models would reduce uncertainties when predicting MeHg risks.
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Affiliation(s)
- Pei Lei
- School of Environment, Nanjing Normal University, Nanjing 210023, China; State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Jinjie Zhu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Suzhou Wuzhong Environmental Monitoring Station, Suzhou 215104, China
| | - Jin Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Mingying Chen
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Environmental and Life Science Program (EnLS), Trent University, Peterborough, Ontario, Canada.
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14
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Wu F, Yang L, Wang X, Yuan W, Lin CJ, Feng X. Mercury Accumulation and Sequestration in a Deglaciated Forest Chronosequence: Insights from Particulate and Mineral-Associated Forms of Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16512-16521. [PMID: 37857302 DOI: 10.1021/acs.est.3c03107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Understanding mercury (Hg) complexation with soil organic matter is important in assessing atmospheric Hg accumulation and sequestration processes in forest ecosystems. Separating soil organic matter into particulate organic matter (POM) and mineral-associated organic matter (MAOM) can help in the understanding of Hg dynamics and cycling due to their very different chemical constituents and associated formation and functioning mechanisms. The concentration of Hg, carbon, and nitrogen contents and isotopic signatures of POM and MAOM in a deglaciated forest chronosequence were determined to construct the processes of Hg accumulation and sequestration. The results show that Hg in POM and MAOM are mainly derived from atmospheric Hg0 deposition. Hg concentration in MAOM is up to 76% higher than that in POM of broadleaf forests and up to 60% higher than that in POM of coniferous forests. Hg accumulation and sequestration in organic soil vary with the vegetation succession. Variations of δ202Hg and Δ199Hg are controlled by source mixing in the broadleaf forest and by Hg sequestration processes in the coniferous forest. Accumulation of atmospheric Hg and subsequent microbial reduction enrich heavier Hg isotopes in MAOM compared to POM due to the specific chemical constituents and nutritional role of MAOM.
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Affiliation(s)
- Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luhan Yang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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15
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Rahman MM, Jung E, Eom S, Lee W, Han S. Mercury concentrations in sediments and oysters in a temperate coastal zone: a comparison of farmed and wild varieties. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:109810-109824. [PMID: 37777705 DOI: 10.1007/s11356-023-29992-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/16/2023] [Indexed: 10/02/2023]
Abstract
Oyster aquaculture has progressively increased to meet growing demands for seafood worldwide; however, its effects on methylmercury (MeHg) production in sediment and accumulation in oysters are largely unknown. In this study, total Hg (THg) and MeHg in sediments collected from aquaculture and reference sites and in farmed and wild oysters were measured and compared to explore potential factors that regulate MeHg production and bioaccumulation at the aquaculture sites. The results showed that the mean concentrations of THg and MeHg in varying sediment depths at the aquaculture site were 34 ± 4.1 ng g-1 and 16 ± 12 pg g-1, respectively. In comparison, the mean concentrations of THg and MeHg in sediments at the reference site were 25 ± 2.5 ng g-1 and 63 ± 28 pg g-1, respectively. While the MeHg/THg in the aquaculture sediments increased with organic carbon content, the slope of MeHg/THg versus organic carbon content was suppressed by high concentrations of dissolved sulfide in the pore water. Multiple parameters (total sulfur, total nitrogen and acid volatile sulfide in sediment, and dissolved sulfide in pore water) showed significant negative relationships with MeHg/THg in the sediment, and the total sulfur content in the sediment showed the highest inverse correlation factor with MeHg/THg (r = - 0.83). The mean concentrations of THg and MeHg in farmed oysters (mean weight 3.2 ± 1.5 g) were 36 ± 10 ng g-1 and 15 ± 6.7 ng g-1, respectively, while those in wild oysters (mean weight 0.92 ± 0.32 g) were 47 ± 9.9 ng g-1 and 15 ± 6.7 ng g-1, respectively. Concerning oysters of the same size range, THg and MeHg levels were higher in farmed oysters than in wild oysters despite the faster growth rate of farmed oysters, suggesting that the Hg content of food sources is more important than growth dilution rates in the control of Hg levels. The mean hazardous quotient for MeHg in farmed oyster was calculated as 0.044 ± 0.020, suggesting no expected health risk from farmed oyster consumption.
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Affiliation(s)
- Md Moklesur Rahman
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Eunji Jung
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Sangwoo Eom
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
| | - Woojin Lee
- Department of Civil and Environmental Engineering, National Lab. Astana, Nazarbayev University, 53 Kabanbay Batyr Ave., Nur-Sultan, 010000, Republic of Kazakhstan
| | - Seunghee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea.
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16
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Li Z, Wu Z, Shao B, Tanentzap AJ, Chi J, He W, Liu Y, Wang X, Zhao Y, Tong Y. Biodegradability of algal-derived dissolved organic matter and its influence on methylmercury uptake by phytoplankton. WATER RESEARCH 2023; 242:120175. [PMID: 37301000 DOI: 10.1016/j.watres.2023.120175] [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: 04/06/2023] [Revised: 05/30/2023] [Accepted: 06/04/2023] [Indexed: 06/12/2023]
Abstract
Methylmercury (MeHg) uptake by phytoplankton represents a key step in determining the exposure risks of aquatic organisms and human beings to this potent neurotoxin. Phytoplankton uptake is believed to be negatively related to dissolved organic matter (DOM) concentration in water. However, microorganisms can rapidly change DOM concentration and composition and subsequent impact on MeHg uptake by phytoplankton has rarely been tested. Here, we explored the influences of microbial degradation on the concentrations and molecular compositions of DOM derived from three common algal sources and tested their subsequent impacts on MeHg uptake by the widespread phytoplankton species Microcystis elabens. Our results indicated that dissolved organic carbon was degraded by 64.3‒74.1% within 28 days of incubating water with microbial consortia from a natural meso‑eutrophic river. Protein-like components in DOM were more readily degraded, while the numbers of molecular formula for peptides-like compounds had increased after 28 days' incubation, probably due to the production and release of bacterial metabolites. Microbial degradation made DOM more humic-like which was consistent with the positive correlations between changes in proportions of Peaks A and C and bacterial abundance in bacterial community structures as illustrated by 16S rRNA gene sequencing. Despite rapid losses of the bulk DOM during the incubation, we found that DOM degraded after 28 days still reduced the MeHg uptake by Microcystis elabens by 32.7‒52.7% relative to a control without microbial decomposers. Our findings emphasize that microbial degradation of DOM would not necessarily enhance the MeHg uptakes by phytoplankton and may become more powerful in inhibiting MeHg uptakes by phytoplankton. The potential roles of microbes in degrading DOM and changing the uptakes of MeHg at the base of food webs should now be incorporated into future risk assessments of aquatic Hg cycling.
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Affiliation(s)
- Zhike Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bo Shao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Andrew J Tanentzap
- Ecosystems and Global Change Group, School of the Environment, Trent University, Peterborough, Ontario K9L 0G2, Canada
| | - Jie Chi
- 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
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xuejun Wang
- College of Urban and Environmental Sciences, Peking University, Beijing 100871, 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; College of Ecology and Environment, Tibet University, Lhasa 850000, China.
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17
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Liu E, Xue J, Zhang G, Wang Y, Wang D, Yin D, He T. Distribution and Release of Mercury Regulated by the Decomposition of a Pioneer Habitat-Adapted Plant in the Water-Level-Fluctuating Zone of the Three Gorges Reservoir. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2023; 111:1. [PMID: 37335383 DOI: 10.1007/s00128-023-03760-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/05/2023] [Indexed: 06/21/2023]
Abstract
Pioneer habitat-adapted bermudagrass is prevalent in the water-level-fluctuating zone of the Three Gorges Reservoir area. This study was performed to explore the response characteristics of dissolved organic matter (DOM) qualities to bermudagrass decomposition and their regulation in the distribution and release of mercury (Hg) and methylmercury (MeHg) in the soil-water system. Compared to the control, the bermudagrass decomposition resulted in a great increase in the protein-like components in the water in the initial stages (p < 0.01), but it also greatly reduced the humification degree of water DOM (p < 0.01). However, it accelerated the consumption of protein-like components, the humification rate, and the synthesis of humic-like DOM in the water over time. This changing pattern of the DOM qualities resulted in an initial elevation and a subsequent great decrease in the dissolved Hg and MeHg concentrations in the pore water, which ultimately reduced their release levels into the overlying water by 26.50% and 54.42%, respectively, compared to the control. Our results indicate the potential inhibitory effects of short-term bermudagrass decomposition caused by flooding and how decomposition affects the release of total Hg and MeHg by shaping the DOM qualities, and they have implications for similar aquatic systems in which herbaceous plants are frequently decomposed after submergence.
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Affiliation(s)
- Enxin Liu
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang, 550025, China
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
- Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang, 550025, China
| | - Jinping Xue
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Ge Zhang
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang, 550025, China
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
- Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang, 550025, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Deliang Yin
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang, 550025, China.
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China.
- Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang, 550025, China.
| | - Tianrong He
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang, 550025, China
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
- Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang, 550025, China
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18
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Liu C, Yuan X, Li Y, Yang Z. Hydrophyte Debris Induced Sedimentary Phosphorus Release in Tuojiang Rivers, China. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2023; 110:103. [PMID: 37284960 DOI: 10.1007/s00128-023-03744-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 05/19/2023] [Indexed: 06/08/2023]
Abstract
Hydrophyte debris decomposition may contribute to phosphorus (P) release from the sediments in riverine systems, but the transport and transformation of organic phosphorus during this process has not been studied well. Here, a ubiquitous hydrophyte in southern China (Alternanthera philoxeroides, A. philoxeroides) was selected to identify the processes and mechanisms of sedimentary P release in late autumn or early spring by laboratory incubation. The results showed that the physio-chemical interactions changed quickly during the beginning of the incubation, where the redox potential and dissolved oxygen at the water-sediment interface decreased rapidly, reaching reducing (299 mV) and anoxic (0.23 mg∙L-1) conditions, respectively. Soluble reactive P, dissolved total P and total P concentrations in overlying water all increased with time from 0.011, 0.025 and 0.169 mg∙L-1 to 0.100, 0.100 and 0.342 mg∙L-1 on average, respectively. Furthermore, the decomposition of A. philoxeroides induced sedimentary organic P release to overlying water, including phosphate monoester (Mono-P), and orthophosphate diesters (Diesters-P). The proportions of Mono-P and Diesters-P were higher at 3 to 9 days than at 11 to 34 days, being 29.4% and 23.3 for Mono-P, 6.3% and 5.7% for Diesters-P, respectively. Orthophosphate (Ortho-P) increased from 63.6 to 69.7% during these timeframes, which indicated the transformations of both Mono-P and Diester-P to bio-available orthophosphate (Ortho-P), causing the rising P concentration in the overlying water. Our results revealed that hydrophyte debris decomposition in river systems might lead to autochthonous P contribution even without external P import from the watershed, accelerating the trophic state of receiving waterbodies.
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Affiliation(s)
- Changling Liu
- POWERCHINA Chengdu Engineering Corporation Limited, Chengdu, 611130, China.
- Sichuan Municipal Water Environment Treatment Engineering Technology Research Center, Chengdu, 611130, China.
| | - Xianfan Yuan
- POWERCHINA Chengdu Engineering Corporation Limited, Chengdu, 611130, China
- State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, 610065, China
- Sichuan Municipal Water Environment Treatment Engineering Technology Research Center, Chengdu, 611130, China
| | - Yuqiong Li
- POWERCHINA Chengdu Engineering Corporation Limited, Chengdu, 611130, China
| | - Zhong Yang
- POWERCHINA Chengdu Engineering Corporation Limited, Chengdu, 611130, China
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Wang T, Yang X, Li Z, Chen W, Wen X, He Y, Ma C, Yang Z, Zhang C. MeHg production in eutrophic lakes: Focusing on the roles of algal organic matter and iron-sulfur-phosphorus dynamics. JOURNAL OF HAZARDOUS MATERIALS 2023; 457:131682. [PMID: 37270963 DOI: 10.1016/j.jhazmat.2023.131682] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/20/2023] [Accepted: 05/21/2023] [Indexed: 06/06/2023]
Abstract
The mechanisms by which eutrophication affects methylmercury (MeHg) production have not been comprehensively summarized, which hinders accurately predicting the MeHg risk in eutrophic lakes. In this review, we first discussed the effects of eutrophication on biogeochemical cycle of mercury (Hg). Special attentions were paid to the roles of algal organic matter (AOM) and iron (Fe)-sulfur (S)-phosphorus (P) dynamics in MeHg production. Finally, the suggestions for risk control of MeHg in eutrophic lakes were proposed. AOM can affect in situ Hg methylation by stimulating the abundance and activities of Hg methylating microorganisms and regulating Hg bioavailability, which are dependent on bacteria-strain and algae species, the molecular weight and composition of AOM as well as environmental conditions (e.g., light). Fe-S-P dynamics under eutrophication including sulfate reduction, FeS formation and P release could also play crucial but complicated roles in MeHg production, in which AOM may participate through influencing the dissolution and aggregation processes, structural order and surface properties of HgS nanoparticles (HgSNP). Future studies should pay more attention to the dynamics of AOM in responses to the changing environmental conditions (e.g., light penetration and redox fluctuations) and how such variations will subsequently affect MeHg production. The effects of Fe-S-P dynamics on MeHg production under eutrophication also deserve further investigations, especially the interactions between AOM and HgSNP. Remediation strategies with lower disturbance, greater stability and less cost like the technology of interfacial O2 nanobubbles are urgent to be explored. This review will deepen our understanding of the mechanisms of MeHg production in eutrophic lakes and provide theoretical guidance for its risk control.
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Affiliation(s)
- Tantan Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Xu Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Zihao Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Wenhao Chen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Xin Wen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Yubo He
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Chi Ma
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Zhongzhu Yang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
| | - Chang Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China.
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20
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Yang X, Li Z, Wang T, Yang Z, Wen X, Yang K, Huang Y, Chen W, He Y, Shi X, Zhang C, Yu Z. Resupply, diffusion, and bioavailability of Hg in paddy soil-water environment with flood-drain-reflood and straw amendment. ENVIRONMENTAL RESEARCH 2023; 231:116127. [PMID: 37187308 DOI: 10.1016/j.envres.2023.116127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/27/2023] [Accepted: 05/11/2023] [Indexed: 05/17/2023]
Abstract
Mercury (Hg) poses a significant risk in paddy fields, particularly when it is converted to methylmercury (MeHg) and accumulates in rice. However, the bioavailability and resupply kinetics of Hg in the paddy soil-water environment are not well understood. In this study, the diffusive gradients in thin films (DGT) and the 'DGT-induced fluxes in sediments' model (DIFS) were first adopted to investigate the Hg resupply kinetics, diffusion fluxes and bioavailability in a paddy environment subjected to flood-drain-reflood treatment and straw amendment. Our results shown that although the straw amendment limited the bioavailability of Hg (38.2%-47.9% lower than control) in porewater by decreasing its resupply capacity, especially with smaller straw particles, the net production of MeHg in paddy fields was significantly increased after straw amendment (73.5%-77.9% higher than control). The results of microbial sequencing indicate that enhanced methylators (e.g., family Geobacter) and non-Hg methylators (e.g., Methanosarcinaceae) played a crucial role in MeHg production following straw amendment. Moreover, Hg-containing paddy soils generally tend to release Hg into the overlying water, while drain-reflood treatment changes the direction of Hg diffusion fluxes in the paddy soil-water interface. The drainage-reflooded treatment decreases the Hg reactive and resupply capacity of the paddy soil, thereby hindering the release of Hg from soil into overlying water during the early stages of reflooding. Overall, this study provides novel insights into the behavior of Hg in paddy soil-water surface microlayers.
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Affiliation(s)
- Xu Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Zihao Li
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Tantan Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Zhongzhu Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Xin Wen
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Kaihua Yang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Yicai Huang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Wenhao Chen
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Yubo He
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China
| | - Xiaohong Shi
- College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Chang Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
| | - Zhigang Yu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD, 4072, Australia.
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Hu J, Yang N, He T, Zhou X, Yin D, Wang Y, Zhou L. Elevated methylmercury production in mercury-contaminated paddy soil resulted from the favorable dissolved organic matter variation created by algal decomposition. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 324:121415. [PMID: 36893976 DOI: 10.1016/j.envpol.2023.121415] [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: 12/22/2022] [Revised: 02/18/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Algae-derived organic matter (AOM) may considerably regulate methylmercury (MeHg) production and accumulation in the paddy fields by changing the soil-dissolved OM (SDOM) properties. In this study, a 25-day microcosm experiment was performed to compare the responding mechanisms of MeHg production in the Hg-contaminated paddy soil-water system to the input of algae-, rice-, and rape-derived OMs. Results showed that algal decomposition could release much more cysteine and sulfate than crop straws. Compared with crop straw-derived OMs, AOM input greatly increased the dissolved organic carbon concentrations in soil but resulted in a greater decrease in tryptophan-like fractions while accelerated the formation of high-molecular-weight fractions in soil DOM. Moreover, AOM input significantly increased MeHg concentrations in the pore water by 19.43%-3427.66% and 52.81%-5846.57% compared to rape- and rice-derived OMs, respectively (P < 0.05). And, a similar MeHg changing pattern was also observed in the overlying water (10-25 d) and the soil solid-phase particles (15-25 d) (P < 0.05). Correlation analysis revealed that MeHg concentrations in the AOM-added soil-water system had significantly negative and positive relationships with the tryptophan-like C4 fraction and molecular weight (E2/E3 ratio) of soil DOM, respectively (P < 0.01). These findings suggest that AOM has a higher capacity than crop straw-derived OMs to promote MeHg production and accumulation in the Hg-contaminated paddy soils by creating a favorable soil DOM variation and providing more microbial electron donors and receptors.
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Affiliation(s)
- Jie Hu
- Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China; College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Ningla Yang
- Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China; College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Tianrong He
- Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China; College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Xian Zhou
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Deliang Yin
- Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang, 550025, China.
| | - Yan Wang
- Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China; College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Litao Zhou
- College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
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22
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Zhang J, Li C, Tang W, Wu M, Chen M, He H, Lei P, Zhong H. Mercury in wetlands over 60 years: Research progress and emerging trends. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161862. [PMID: 36716881 DOI: 10.1016/j.scitotenv.2023.161862] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/04/2023] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
Wetlands are considered the hotspots for mercury (Hg) biogeochemistry, garnering global attention. Therefore, it is important to review the research progress in this field and predict future frontiers. To achieve that, we conducted a literature analysis by collecting 15,813 publications about Hg in wetlands from the Web of Science Core Collection. The focus of wetland Hg research has changed dramatically over time: 1) In the initial stage (i.e., 1959-1990), research mainly focused on investigating the sources and contents of Hg in wetland environments and fish. 2) For the next 20 years (i.e., 1991-2010), Hg transformation (e.g., Hg reduction and methylation) and environmental factors that affect Hg bioaccumulation have attracted extensive attention. 3) In the recent years of 2011-2022, hot topics in Hg study include microbial Hg methylators, Hg bioavailability, methylmercury (MeHg) demethylation, Hg stable isotope, and Hg cycling in paddy fields. Finally, we put forward future research priorities, i.e., 1) clarifying the primary factors controlling MeHg production, 2) uncovering the MeHg demethylation process, 3) elucidating MeHg bioaccumulation process to better predict its risk, and 4) recognizing the role of wetlands in Hg circulation. This research shows a comprehensive knowledge map for wetland Hg research and suggests avenues for future studies.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Chengjun Li
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China
| | - Wenli Tang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Mengjie Wu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Mingying Chen
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Pei Lei
- School of Environment, Nanjing Normal University, Nanjing 210023, China.
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Environmental and Life Science Program (EnLS), Trent University, Peterborough, Ontario, Canada
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23
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Zhang S, Yin Y, Yang P, Yao C, Tian S, Lei P, Jiang T, Wang D. Using the end-member mixing model to evaluate biogeochemical reactivities of dissolved organic matter (DOM): autochthonous versus allochthonous origins. WATER RESEARCH 2023; 232:119644. [PMID: 36736245 DOI: 10.1016/j.watres.2023.119644] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 01/02/2023] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Dissolved organic matter (DOM) is an essential component of environmental systems. It usually originates from two end-members, including allochthonous and autochthonous sources. Previously, links have been established between DOM origins/sources and its biogeochemical reactivities. However, the influence of changes in DOM characteristics driven by end-member mixing on DOM biogeochemical reactivities has not been clarified. In this study, we investigated variations of DOM reactivities responding to the dynamics of DOM characteristics induced by different mixing ratios of two DOM end-members derived from humic acid (HA) and algae, respectively. Four biogeochemical reactivities of DOM were evaluated, including biodegradation, ·OH production, photodegradation, and redox capacity. Results showed that the variations of DOM characteristics due to the two end-members mixing significantly impact its biogeochemical reactivities. However, not all spectral parameters and reactivities followed the conservative mixing behavior. In contrast to reactivities of ·OH production and redox capacity, mixed samples showed apparent deviations from conservative linear relationships in biodegradation and photodegradation due to the interaction between the two end-members. Regarding the role of DOM properties influencing reactivity changes, peak A and M were recognized as the most stable parameters. However, peak C and SUVA254 were identified as the most vital contributors for explaining DOM reactivity variations. These findings suggest that a general model for describing the dynamic relationship between DOM source and reactivity cannot be proposed. Thus, the dynamics of DOM reactivity in diverse ecosystems cannot be estimated simply by the "plus or minus" of the reactivity from individual end-member. The effect of end-member mixing should be evaluated in a given reactivity instead of generalization. This study provides important insights for further understanding the dynamics of DOM's environmental role in different ecosystems influenced by variations of source inputs. In future, more field investigations are needed to further verify our findings in this study, especially in the scenario of end-member mixing.
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Affiliation(s)
- Siqi Zhang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Peijie Yang
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Cong Yao
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Shanyi Tian
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Pei Lei
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China.
| | - Dingyong Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, Department of Environmental Sciences and Engineering, College of Resources and Environment, Southwest University, Chongqing 400716, China
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Li Z, Chi J, Shao B, Wu Z, He W, Liu Y, Sun P, Lin H, Wang X, Zhao Y, Chen L, Tong Y. Inhibition of methylmercury uptake by freshwater phytoplankton in presence of algae-derived organic matter. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120111. [PMID: 36075338 DOI: 10.1016/j.envpol.2022.120111] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
As the first step of methylmercury (MeHg) entry into the aquatic food webs, MeHg uptake by phytoplankton is crucial in determining the final human MeHg exposure risks. MeHg availability to plankton is regulated by dissolved organic matter (DOM) in the water, while the extent of the impacts can vary largely based on the sources of DOM. Here, we investigated impacts of DOM sources on MeHg bioconcentration by three freshwater phytoplankton species (i.e. S. quadricauda, Chlorella sp., Microcystis elabens) in the laboratory system. We found that algae-derived DOM would prohibited the cellular MeHg bioconcentration by a percent up to 77-93%, while the soil-derived DOM didn't show similar inhibition effects. DOM characterization by the excitation‒emission matrices, Fourier transform infrared spectrum, ultra‒high performance liquid chromatography‒tandem quadrupole time of flight mass spectrometry shown that the molecular size of S-containing compound, rather than thiol concentration, has played a crucial role in regulating the MeHg uptake by phytoplankton. Climate change and increasing nutrient loadings from human activities may affect plankton growth in the freshwater, ultimately changing the DOM compositions. Impacts of these changes on cellular MeHg uptakes by phytoplankton should be emphasized when exploring the aquatic Hg cycling and evaluating their risks to human beings and wild life.
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Affiliation(s)
- Zhike Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Jie Chi
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Bo Shao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Zhengyu Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Wei He
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Peizhe Sun
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Huiming Lin
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Xuejun Wang
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Long Chen
- School of Geographic Sciences, East China Normal University, Shanghai, 200241, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
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Tang Y, Liu X, Tian R, Li R, Li H. Risk Assessment and Source Identification of Arsenic in Surface Sediments from Caohai Lake, China. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2022; 109:698-705. [PMID: 34988608 DOI: 10.1007/s00128-021-03418-x] [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: 07/30/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Urban freshwaters containing arsenic are facing an increasing problem of eutrophication. This study evaluated the spatial distribution, ecological risk, and origin of As in surface sediments obtained from Caohai Lake, a typical hypertrophic urban lake in China. It revealed that the total As concentration in surface sediments decreased gradually from north to south, consisted with the lake eutrophication status. The average As level was 161 mg/kg, dominated by reducible and oxidisable fractions. The analyses of geoaccumulation index and enrichment factor indicated that As ranged between moderately-to-heavily and heavily contamination, was severely influenced by anthropogenic factors, i.e. industrial discharges and agricultural activities. Risk assessment code and potential ecological risk index results showed moderate to high potential ecological risk could be observed although the current As risk was low, supporting by the experimentally quantified As release data.
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Affiliation(s)
- Ying Tang
- Chongqing Key Laboratory of Soil Multi-Scale Interfacial Process, Department of Soil Science, College of Resources and Environment, Southwest University, Chongqing, 400715, China.
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Xinmin Liu
- Chongqing Key Laboratory of Soil Multi-Scale Interfacial Process, Department of Soil Science, College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Rui Tian
- Chongqing Key Laboratory of Soil Multi-Scale Interfacial Process, Department of Soil Science, College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Rui Li
- Chongqing Key Laboratory of Soil Multi-Scale Interfacial Process, Department of Soil Science, College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Hang Li
- Chongqing Key Laboratory of Soil Multi-Scale Interfacial Process, Department of Soil Science, College of Resources and Environment, Southwest University, Chongqing, 400715, China
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26
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Li H, Li Y, Tang W, Zhong H, Zhao J, Bai X, Sha S, Xu D, Lei P, Gao Y. Assessment of the Bioavailability of Mercury Sulfides in Paddy Soils Using Sodium Thiosulfate Extraction - Results from Microcosm Experiments. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2022; 109:764-770. [PMID: 35305130 DOI: 10.1007/s00128-022-03483-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: 11/28/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Mercury sulfides (HgS), one of the largest Hg sinks in the lithosphere, has long been considered to be highly inert. Recently, several HgS speciation (e.g., nano- or micro-sized HgS particles) in paddy soils have been found to be reactive and bioavailable, increasing the possibility of methylation and bioaccumulation and posing a potential risk to humans. However, a simple and uniform method for investigating HgS bioavailability is still lacking. To address this issue, we extracted dissolved Hg from HgS particles by sodium thiosulfate (Na2S2O3) in paddy soils and analyzed the correlation between extracted Hg and soil methylmercury (MeHg). Results showed that the amounts of Hg extracted by Na2S2O3 had a strong positive correlation with the levels of soil MeHg (R 2 adj = 0.893, p < 0.05). It is suggested that Na2S2O3 extraction may be a good method of predicting Hg bioavailability in paddy soils. Our results would help to give clues in better predicting Hg risk in natural environments.
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Affiliation(s)
- Hong Li
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
- Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
| | - Yunyun Li
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
| | - Wenli Tang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, 210023, Nanjing, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, 210023, Nanjing, China
| | - Jiating Zhao
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
| | - Xu Bai
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Shengnan Sha
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Diandou Xu
- Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
| | - Pei Lei
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, 210023, Nanjing, China.
| | - Yuxi Gao
- CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China.
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27
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Li P, Wang R, Kainz MJ, Yin D. Algal Density Controls the Spatial Variations in Hg Bioconcentration and Bioaccumulation at the Base of the Pelagic Food Web of Lake Taihu, China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14528-14538. [PMID: 36194456 DOI: 10.1021/acs.est.2c05625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Algal density can significantly impact mercury (Hg) bioaccumulation and biomagnification in aquatic food webs, but the underlying mechanisms remain controversial especially in subtropical and tropical regions. We conducted a comprehensive field study on Hg bioconcentration in phytoplankton and bioaccumulation in size-fractionated zooplankton across 17 sampling sites in Lake Taihu, a large shallow lake in eastern China with large spatial differences in algal density. The higher algal density in the northern sites is highly associated with the lower THg bioconcentration factor (BCF) in phytoplankton and lower THg bioaccumulation factor (BAF) in zooplankton. The low Hg BCFs or BAFs at productive sites could not be explained by algal bloom dilution but attributed to the low Hg bioavailability, which is highly associated with the elevated pH levels at productive sites. The smaller body size of the dominant zooplankton species at higher algal density sites also contributed to their lower Hg bioaccumulation. Importantly, we provide evidence that high algal density is associated with a low proportion of methylmercury (MeHg) in total Hg (% MeHg) in phytoplankton, which is further transferred to zooplankton. Such a low THg BCF or BAF and low % MeHg in plankton at high algal density sites hamper the entry of Hg into the pelagic food webs, which are important but yet underestimated driving forces for the low Hg contents in pelagic fish that are commonly observed in anthropogenic-impacted eutrophic lakes in subtropical regions.
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Affiliation(s)
- Pengwei Li
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai200092, China
| | - Rui Wang
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai200092, China
| | - Martin J Kainz
- WasserCluster Lunz - Biologische Station, Inter-University Center for Aquatic Ecosystem Research, A-3293Lunz am See, Austria
- Department of Biomedical Research, Danube University Krems, A-3500Krems, Austria
| | - Daqiang Yin
- Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai200092, China
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28
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Capo E, Feng C, Bravo AG, Bertilsson S, Soerensen AL, Pinhassi J, Buck M, Karlsson C, Hawkes J, Björn E. Expression Levels of hgcAB Genes and Mercury Availability Jointly Explain Methylmercury Formation in Stratified Brackish Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13119-13130. [PMID: 36069707 PMCID: PMC9494745 DOI: 10.1021/acs.est.2c03784] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Neurotoxic methylmercury (MeHg) is formed by microbial methylation of inorganic divalent Hg (HgII) and constitutes severe environmental and human health risks. The methylation is enabled by hgcA and hgcB genes, but it is not known if the associated molecular-level processes are rate-limiting or enable accurate prediction of MeHg formation in nature. In this study, we investigated the relationships between hgc genes and MeHg across redox-stratified water columns in the brackish Baltic Sea. We showed, for the first time, that hgc transcript abundance and the concentration of dissolved HgII-sulfide species were strong predictors of both the HgII methylation rate and MeHg concentration, implying their roles as principal joint drivers of MeHg formation in these systems. Additionally, we characterized the metabolic capacities of hgc+ microorganisms by reconstructing their genomes from metagenomes (i.e., hgc+ MAGs), which highlighted the versatility of putative HgII methylators in the water column of the Baltic Sea. In establishing relationships between hgc transcripts and the HgII methylation rate, we advance the fundamental understanding of mechanistic principles governing MeHg formation in nature and enable refined predictions of MeHg levels in coastal seas in response to the accelerating spread of oxygen-deficient zones.
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Affiliation(s)
- Eric Capo
- Department
of Chemistry, Umeå University, Umeå 901 87, Sweden
- Department
of Aquatic Sciences and Assessment, Swedish
University of Agricultural Sciences, Uppsala 750 07, Sweden
| | - Caiyan Feng
- Department
of Chemistry, Umeå University, Umeå 901 87, Sweden
| | - Andrea G. Bravo
- Department
of Marine Biology and Oceanography, Institute of Marine Sciences, Spanish National Research Council (CSIC), Barcelona 08003, Spain
| | - Stefan Bertilsson
- Department
of Aquatic Sciences and Assessment, Swedish
University of Agricultural Sciences, Uppsala 750 07, Sweden
| | - Anne L. Soerensen
- Department
of Environmental Research and Monitoring, Swedish Museum of Natural History, Stockholm 104 05, Sweden
| | - Jarone Pinhassi
- Centre
for Ecology and Evolution in Microbial Model Systems—EEMiS, Linnaeus University, Kalmar 391 82, Sweden
| | - Moritz Buck
- Department
of Aquatic Sciences and Assessment, Swedish
University of Agricultural Sciences, Uppsala 750 07, Sweden
| | - Camilla Karlsson
- Centre
for Ecology and Evolution in Microbial Model Systems—EEMiS, Linnaeus University, Kalmar 391 82, Sweden
| | - Jeffrey Hawkes
- Department
of Chemistry, Uppsala University, Uppsala 751 23, Sweden
| | - Erik Björn
- Department
of Chemistry, Umeå University, Umeå 901 87, Sweden
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29
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Lei P, Zou N, Liu Y, Cai W, Wu M, Tang W, Zhong H. Understanding the risks of mercury sulfide nanoparticles in the environment: Formation, presence, and environmental behaviors. J Environ Sci (China) 2022; 119:78-92. [PMID: 35934468 DOI: 10.1016/j.jes.2022.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 01/16/2022] [Accepted: 02/10/2022] [Indexed: 06/15/2023]
Abstract
Mercury (Hg) could be microbially methylated to the bioaccumulative neurotoxin methylmercury (MeHg), raising health concerns. Understanding the methylation of various Hg species is thus critical in predicting the MeHg risk. Among the known Hg species, mercury sulfide (HgS) is the largest Hg reservoir in the lithosphere and has long been considered to be highly inert. However, with advances in the analytical methods of nanoparticles, HgS nanoparticles (HgS NPs) have recently been detected in various environmental matrices or organisms. Furthermore, pioneering laboratory studies have reported the high bioavailability of HgS NPs. The formation, presence, and transformation (e.g., methylation) of HgS NPs are intricately related to several environmental factors, especially dissolved organic matter (DOM). The complexity of the behavior of HgS NPs and the heterogeneity of DOM prevent us from comprehensively understanding and predicting the risk of HgS NPs. To reveal the role of HgS NPs in Hg biogeochemical cycling, research needs should focus on the following aspects: the formation pathways, the presence, and the environmental behaviors of HgS NPs impacted by the dominant influential factor of DOM. We thus summarized the latest progress in these aspects and proposed future research priorities, e.g., developing the detection techniques of HgS NPs and probing HgS NPs in various matrices, further exploring the interactions between DOM and HgS NPs. Besides, as most of the previous studies were conducted in laboratories, our current knowledge should be further refreshed through field observations, which would help to gain better insights into predicting the Hg risks in natural environment.
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Affiliation(s)
- Pei Lei
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Nan Zou
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Yujiao Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Weiping Cai
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengjie Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Wenli Tang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Huan Zhong
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China; Environmental and Life Sciences Program (EnLS), Trent University, Peterborough Ontario, K9L 0G2, Canada.
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30
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Wu Z, Li Z, Shao B, Zhang Y, He W, Lu Y, Gusvitskii K, Zhao Y, Liu Y, Wang X, Tong Y. Impact of dissolved organic matter and environmental factors on methylmercury concentrations across aquatic ecosystems inferred from a global dataset. CHEMOSPHERE 2022; 294:133713. [PMID: 35074323 DOI: 10.1016/j.chemosphere.2022.133713] [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: 10/14/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Mercury (Hg) input into ecosystems is estimated to have increased by twofold to fivefold since the industrial revolution. In aquatic ecosystems, methylmercury (MeHg) receives the most attentions of all the Hg species due to its neurotoxicity and strong bioaccumulation capacity in food chain. Dissolved organic matter (DOM) is crucial in impacting aquatic Hg transformation. However, only few spatially constrained studies have attempted to quantify the relative importance of DOM and other factors (e.g., Hg availability, temperature, pH, and land-use type) on MeHg concentration. In this study, we collected data of 585 water samples at 373 sites globally, including lakes, rivers, estuaries, and wetlands, and characterized the global pattern of MeHg distribution and environmental drivers of aquatic MeHg concentration. Our results showed that MeHg concentrations ranged from detection limits to 11 (geometric mean 0.11 and average 0.29) ng/L, and the highest MeHg concentration and Hg methylation potential were observed in wetlands. A positive relationship was observed between MeHg fraction in the total mercury (THg) and DOM for all the aquatic ecosystems. Using the structural equation modeling, we found that Hg availability was a dominant factor in impacting water MeHg concentration followed by DOM. According to 129 samples of specific DOM source information, we found that the percentage of THg as MeHg (%MeHg) in water dominated by the autochthonous DOM was higher than that dominated by the allochthonous DOM. Our results could advance understanding of aquatic Hg cycling and their environmental drivers, which are fundamental for predicting and mitigating MeHg productions and its potential health risks for humans.
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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
| | - Yiyan Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Wei He
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Yiren Lu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Kair Gusvitskii
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
| | - Yingxin Zhao
- 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
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
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31
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Liang X, Zhu N, Johs A, Chen H, Pelletier DA, Zhang L, Yin X, Gao Y, Zhao J, Gu B. Mercury Reduction, Uptake, and Species Transformation by Freshwater Alga Chlorella vulgaris under Sunlit and Dark Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4961-4969. [PMID: 35389633 DOI: 10.1021/acs.est.1c06558] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
As a major entry point of mercury (Hg) to aquatic food webs, algae play an important role in taking up and transforming Hg species in aquatic ecosystems. However, little is known how and to what extent Hg reduction, uptake, and species transformations are mediated by algal cells and their exudates, algal organic matter (AOM), under either sunlit or dark conditions. Here, using Chlorella vulgaris (CV) as one of the most prevalent freshwater model algal species, we show that solar irradiation could enhance the reduction of mercuric Hg(II) to elemental Hg(0) by both CV cells and AOM. AOM reduced more Hg(II) than algal cells themselves due to cell surface adsorption and uptake of Hg(II) inside the cells under solar irradiation. Synchrotron radiation X-ray absorption near-edge spectroscopy (SR-XANES) analyses indicate that sunlight facilitated the transformation of Hg to less bioavailable species, such as β-HgS and Hg-phytochelatins, compared to Hg(Cysteine)2-like species formed in algal cells in the dark. These findings highlight important functional roles and potential mechanisms of algae in Hg reduction and immobilization under varying lighting conditions and how these processes may modulate Hg cycling and bioavailability in the aquatic environment.
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Affiliation(s)
- Xujun Liang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- School of Resources and Environment Science, Quanzhou Normal University, Quanzhou 362000, China
| | - Nali Zhu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Alexander Johs
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Hongmei Chen
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dale A Pelletier
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Lijie Zhang
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Xixiang Yin
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yuxi Gao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Jiating Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee 37996, United States
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