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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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2
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Imtiazy MN, Hunter K, Hudson JJ. In-reservoir transformation of dissolved organic matter as a function of hydrological flow. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 352:120099. [PMID: 38232598 DOI: 10.1016/j.jenvman.2024.120099] [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: 09/23/2023] [Revised: 12/21/2023] [Accepted: 01/08/2024] [Indexed: 01/19/2024]
Abstract
Reservoirs are vital to meet the ever-increasing demands for freshwater in a warming climate. Dissolved organic matter (DOM) represents an important pool of carbon and can be a major concern in drinking water sources. However, insights into DOM dynamics in temperate, semi-arid reservoirs remain limited. Therefore, we investigated the variations in DOM properties in Lake Diefenbaker, a large reservoir on the Canadian Prairies, by analyzing eight years of DOM concentrations and composition through linear mixed effect modeling. Contrary to expectations, reservoir dissolved organic carbon (DOC) concentration showed no correlation with inflow from the South Saskatchewan River (p = 0.12), while dissolved organic nitrogen (DON) increased with decreasing inflow (p = 0.002). DOM optical indices (SUVA254 and E4:E6 ratio) and DOC:DON ratio revealed a pronounced influence of inflow on reservoir DOM composition (p < 0.001), i.e., allochthonous characteristics increased with increasing flow, and autochthonous characteristics increased with declining flow. Travel time corrected comparison of approximately the same water parcel along the reservoir length revealed that increasing water residence time in downstream regions led to a significant transformation in DOM composition, favoring autochthonous characteristics (mean SUVA254 reduced by 0.52 L mg-C-1 m-1, and the E4:E6 and spectral slope ratio increased by 1.6 and 0.06, respectively). Autochthonous DOC inputs likely offset the allochthonous DOC losses, which resulted in a relatively stable DOC concentration throughout the reservoir (mean 3.7 mg L-1). Additionally, the effect of a large aquaculture operation on reservoir DOM properties was investigated, but no effect was detected. The results have significant implications for managing large river-reservoirs. Autochthonous DOM poses challenges to water processing, necessitating monitoring of DOM composition for reservoir drinking water quality. Insights on climate-induced changes in DOM properties will also assist with understanding changes to habitat conditions and contaminant transport.
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Affiliation(s)
- Md Noim Imtiazy
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Kristine Hunter
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
| | - Jeff J Hudson
- Department of Biology, University of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
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3
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Willacker J, Eagles-Smith CA, Chandler JA, Naymik J, Myers R, Krabbenhoft DP. Reservoir Stratification Modulates the Influence of Impoundments on Fish Mercury Concentrations along an Arid Land River System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21313-21326. [PMID: 38051342 PMCID: PMC10734268 DOI: 10.1021/acs.est.3c04646] [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: 06/26/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 12/07/2023]
Abstract
Impoundment is among the most common hydrologic alterations with impacts on aquatic ecosystems that can include effects on mercury (Hg) cycling. However, landscape-scale differences in Hg bioaccumulation between reservoirs and other habitats are not well characterized nor are the processes driving these differences. We examined total Hg (THg) concentrations of Smallmouth Bass (Micropterus dolomieu) collected from reservoir, tailrace, and free-flowing reaches along an 863 km segment of the Snake River, USA, a semiarid river with 22 impoundments along its course. Across three size-classes (putative 1-year-old, first reproductive, and harvestable sized fish), THg concentrations in reservoirs and tailraces averaged 76% higher than those in free-flowing segments. Among reservoirs, THg concentrations were highest in reservoirs with inconsistent stratification patterns, 47% higher than annually stratified, and 144% higher than unstratified reservoirs. Fish THg concentrations in tailraces immediately downstream of stratified reservoirs were higher than those below unstratified (38-130%) or inconsistently stratified (32-79%) reservoirs. Stratification regimes influenced the exceedance of fish and human health benchmarks, with 52-80% of fish from stratifying reservoirs and downstream tailraces exceeding a human consumption benchmark, compared to 6-17% where stratification did not occur. These findings suggest that impoundment and stratification play important roles in determining the patterns of Hg exposure risk across the landscape.
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Affiliation(s)
- James
J. Willacker
- U.S.
Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon 97331, United States
| | - Collin A. Eagles-Smith
- U.S.
Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200 SW Jefferson Way, Corvallis, Oregon 97331, United States
| | - James A. Chandler
- Idaho
Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Jesse Naymik
- Idaho
Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Ralph Myers
- Idaho
Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - David P. Krabbenhoft
- U.S.
Geological Survey, Upper Midwest Water Science Center, 8505 Research Way, Middleton, Wisconsin 53562, United States
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4
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Li Z, Wang T, Yang X, Wen X, Chen W, He Y, Yu Z, Zhang C. Microbial community function and methylmercury production in oxygen-limited paddy soil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 266:115585. [PMID: 37856980 DOI: 10.1016/j.ecoenv.2023.115585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 10/03/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
Methylmercury is a neurotoxic compound that can enter rice fields through rainfall or irrigation with contaminated wastewater, and then contaminate the human food chain through the consumption of rice. Flooded paddy soil has a porous structure that facilitates air exchange with the atmosphere, but the presence of trace amounts of oxygen in flooded rice field soil and its impact on microbial-mediated formation of methylmercury is still unclear. We compared the microbial communities and their functions in oxygen-depleted and oxygen-limited paddy soil. We discovered that oxygen-limited paddy soil had higher methylmercury concentration, which was strongly correlated with soil properties and methylation potential. Compared with oxygen-depleted soil, oxygen-limited soil altered the microbial composition based on 16 S rRNA sequences, but not based on hgcA sequences. Moreover, oxygen-limited soil enhanced microbial activity significantly, increasing the abundance of more than half of the KEGG pathways, especially the metabolic pathways that might be involved in methylation. Our study unveils how microbial communities influence methylmercury formation in oxygen-limited paddy soil. ENVIRONMENTAL IMPLICATIONS: This study examined how low oxygen input affects microbial-induced MeHg formation in anaerobic paddy soil. We found that oxygen-limited soil produced more MeHg than oxygen-depleted soil. Oxygen input altered the microbial community structure of 16 S rRNA sequencing in anaerobic paddy soil, but had little impact on the hgcA sequencing community structure. Microbial activity and metabolic functions related to MeHg formation were also higher in oxygen-limited paddy soil. We suggest that oxygen may not be a limiting factor for Hg methylators, and that insufficient oxygen input in flooded paddy soil increases the risk of human exposure to MeHg from rice consumption.
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Affiliation(s)
- 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
| | - 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
| | - 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
| | - 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
| | - Zhigang Yu
- Australian Center for Water and Environmental Biotechnology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - 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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5
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Ziaei H, Rao B, Wood TV, Garza-Rubalcava U, Alborzi A, Zhou H, Bireta P, Grosso N, Reible D. Assessment and Management of Mercury Leaching from a Riverbank. TOXICS 2023; 11:179. [PMID: 36851054 PMCID: PMC9962584 DOI: 10.3390/toxics11020179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
The South River located in the city of Waynesboro, Virginia, contains mercury (Hg) contamination due to historical releases from an industrial facility operating between 1929 and 1950. In 2015, two sampling events were conducted in two of the contaminated bank regions (Constitution Park and North Park) to evaluate non-particulate total mercury (THg) and methylmercury (MeHg) concentrations in bank interstitial waters during river base flows and during bank drainage after flooding events. Porewater THg and MeHg at the bank-water interface were measured using diffusive gradient in thin-film devices (DGTs). The results showed THg mercury concentrations during bank drainage were approximately a factor of 3 higher than during base flow conditions. To have a better understanding of the parameters that control Hg leaching, a series of laboratory experiments were designed using South River sediments. The field and laboratory assessment showed that drainage/inundation cycles can lead to high THg concentration leachate from contaminated sediment due to increased partitioning from solids under oxic bank conditions and mobilization by the drainage waters. The results also demonstrated that methyl mercury concentrations at the bank-water interface are highest under base flow when conditions are more reduced due to the absence of oxic water exchange with the surface water. A remedial approach was implemented involving partial removal of surficial sediments and placement of biochar (to reduce non-particulate THg) and an armoring layer (to reduce erosion). DGT Measurements after bank stabilization showed THg decreased by a factor of ~200 and MeHg concentration by a factor of more than 20.
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Affiliation(s)
- Hasti Ziaei
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Balaji Rao
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Tea V. Wood
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | | | - Ashkan Alborzi
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Huayun Zhou
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Paul Bireta
- Department of Civil Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA
| | - Nancy Grosso
- Corteva Agriscience, Indianapolis, IN 46268, USA
| | - Danny Reible
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
- Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409, USA
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6
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Eckley CS, Eagles-Smith C, Luxton TP, Hoffman J, Janssen S. Using mercury stable isotope fractionation to identify the contribution of historical mercury mining sources present in downstream water, sediment and fish. FRONTIERS IN ENVIRONMENTAL CHEMISTRY 2023; 4:1096199. [PMID: 37323923 PMCID: PMC10269370 DOI: 10.3389/fenvc.2023.1096199] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ecosystems downstream of mercury (Hg) contaminated sites can be impacted by both localized releases as well as Hg deposited to the watershed from atmospheric transport. Identifying the source of Hg in water, sediment, and fish downstream of contaminated sites is important for determining the effectiveness of source-control remediation actions. This study uses measurements of Hg stable isotopes in soil, sediment, water, and fish to differentiate between Hg from an abandoned Hg mine from non-mine-related sources. The study site is located within the Willamette River watershed (Oregon, United States), which includes free-flowing river segments and a reservoir downstream of the mine. The concentrations of total-Hg (THg) in the reservoir fish were 4-fold higher than those further downstream (>90 km) from the mine site in free-flowing sections of the river. Mercury stable isotope fractionation analysis showed that the mine tailings (δ202Hg: -0.36‰ ± 0.03‰) had a distinctive isotopic composition compared to background soils (δ202Hg: -2.30‰ ± 0.25‰). Similar differences in isotopic composition were observed between stream water that flowed through the tailings (particulate bound δ202Hg: -0.58‰; dissolved: -0.91‰) versus a background stream (particle-bound δ202Hg: -2.36‰; dissolved: -2.09‰). Within the reservoir sediment, the Hg isotopic composition indicated that the proportion of the Hg related to mine-release increased with THg concentrations. However, in the fish samples the opposite trend was observed-the degree of mine-related Hg was lower in fish with the higher THg concentrations. While sediment concentrations clearly show the influence of the mine, the relationship in fish is more complicated due to differences in methylmercury (MeHg) formation and the foraging behavior of different fish species. The fish tissue δ13C and Δ199Hg values indicate that there is a higher influence of mine-sourced Hg in fish feeding in a more sediment-based food web and less so in planktonic and littoral-based food webs. Identifying the relative proportion of Hg from local contaminated site can help inform remediation decisions, especially when the relationship between total Hg concentrations and sources do not show similar covariation between abiotic and biotic media.
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Affiliation(s)
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, United States
| | - Todd P. Luxton
- US EPA ORD, Center for Environmental Solutions and Emergency Response, Cincinnati, OH, United States
| | - Joel Hoffman
- U.S. EPA Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, Duluth, MN, United States
| | - Sarah Janssen
- U.S. Geological Survey, Mercury Research Lab, Upper Midwest Water Science Center, Madison, WI, United States
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7
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Millard G, Eckley CS, Luxton TP, Krabbenhoft D, Goetz J, McKernan J, DeWild J. Evaluating the influence of seasonal stratification on mercury methylation rates in the water column and sediment in a contaminated section of a western U.S.A. reservoir. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120485. [PMID: 36279994 PMCID: PMC10259237 DOI: 10.1016/j.envpol.2022.120485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 06/14/2023]
Abstract
Mercury methylation frequently occurs at the active oxic/anoxic boundary between the sediment bed and water column of lakes and reservoirs. Previous studies suggest that the predominant mercury methylation zone moves to the water column during periods of stratification and that high potential methylation rates (Km) in sediment require oxygenated overlying water. However, simultaneous measurements of methylmercury (MeHg) production in both the sediment and water column remain limited. Understanding the relative importance of sediment versus water column methylation and the impact of seasonal stratification on these processes has important implications for managing MeHg production. This study measured Km and potential demethylation rates (Kdm) using stable isotope tracers of unfiltered inorganic mercury and MeHg in sediments and water of the littoral and profundal zones of a shallow branch of the Nacimiento Reservoir in California's central coastal range. Field sampling was conducted once during winter (well-mixed/oxygenated conditions) and once during late summer (thermally stratified/anoxic conditions). The results showed very high ambient MeHg concentrations in hypolimnetic waters (up to 7.5 ng L-1; 79% MeHg/total Hg). During late summer, littoral sediments had higher Km (0.024 day-1) compared to profundal sediments (0.013 day-1). Anoxic water column Km were of similar magnitude to Km in the sediment (0.03 day-1). Following turnover, profundal sediment Km did not change significantly, but water column Km became insignificant. Summer and winter sediment Kdm were higher in profundal (2.35, 3.54 day-1, respectively) compared to the littoral sediments (0.52, 2.56 day-1, respectively). When modelled, Km in the water column could account for approximately 40% of the hypolimnetic MeHg. Our modelling results show that the remaining MeHg in the hypolimnion could originate from the profundal sediment. While further study is needed, these results suggest that addressing methylation in the water column and profundal sediment are of equal importance to any remediation strategy.
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Affiliation(s)
- Geoffrey Millard
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - Chris S Eckley
- U.S.A. Environmental Protection Agency, Region 10, 1200 Sixth Avenue, Suite 155, Seattle WA, 98101, USA.
| | - Todd P Luxton
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - David Krabbenhoft
- U.S.A. Geological Survey, Mercury Research Laboratory, 2280 Woodale Drive, Mounds View MN, 55112, USA.
| | - Jennifer Goetz
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - John McKernan
- U.S.A. Environmental Protection Agency, Office of Research and Development, 26 W Martin Luther King Dr, Cincinnati, OH, 45220, USA.
| | - John DeWild
- U.S.A. Geological Survey, Mercury Research Laboratory, 2280 Woodale Drive, Mounds View MN, 55112, USA.
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8
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Seelos M, Beutel M, McCord S, Kim S, Vigil K. Plankton population dynamics and methylmercury bioaccumulation in the pelagic food web of mine-impacted surface water reservoirs. HYDROBIOLOGIA 2022; 849:4803-4822. [PMID: 36213552 PMCID: PMC9526464 DOI: 10.1007/s10750-022-05018-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/02/2022] [Accepted: 09/16/2022] [Indexed: 05/28/2023]
Abstract
UNLABELLED Thermal stratification of reservoirs can lead to anaerobic conditions that facilitate the microbial conversion of mercury (Hg) to neurotoxic and bioaccumulative methylmercury (MeHg). But MeHg production is just the first step in a complex set of processes that affect MeHg in fish. Of particular relevance is uptake into suspended particulate matter (SPM) and zooplankton at the base of the pelagic food web. We assessed plankton dynamics and Hg uptake into the pelagic food web of four Hg-impaired California water reservoirs. Combining water chemistry, plankton taxonomy, and stable carbon (C) and nitrogen (N) isotope values of SPM and zooplankton samples, we investigated differences among the reservoirs that may contribute to differing patterns in MeHg bioaccumulation. Methylmercury accumulated in SPM during the spring and summer seasons. Percent MeHg (MeHg/Hg*100%) in SPM was negatively associated with δ15N values, suggesting that "fresh" algal biomass could support the production and bioaccumulation of MeHg. Zooplankton δ13C values were correlated with SPM δ13C values in the epilimnion, suggesting that zooplankton primarily feed in surface waters. However, zooplankton MeHg was poorly associated with MeHg in SPM. Our results demonstrate seasonal patterns in biological MeHg uptake and how multiple data sources can help constrain the drivers of MeHg bioaccumulation. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10750-022-05018-0.
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Affiliation(s)
- Mark Seelos
- Environmental Systems Graduate Program, University of California Merced, Merced, CA 95343 USA
- Valley Water, San Jose, CA 95118 USA
| | - Marc Beutel
- Environmental Systems Graduate Program, University of California Merced, Merced, CA 95343 USA
| | | | - Sora Kim
- Department of Life and Environmental Sciences, University of California Merced, Merced, CA 95343 USA
| | - Katie Vigil
- Department of Global Environmental Health, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112 USA
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9
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Wang J, Xiang Y, Tian X, Zhang C, Gong G, Xue J, Jiang T, Wang D, Wang Y. Role of the rhizosphere of a flooding-tolerant herb in promoting mercury methylation in water-level fluctuation zones. J Environ Sci (China) 2022; 119:139-151. [PMID: 35934459 DOI: 10.1016/j.jes.2022.05.008] [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: 02/24/2022] [Revised: 04/26/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
The water-level fluctuation zone (WLFZ) has been considered as a hotspot for mercury (Hg) methylation. Flooding-tolerant herbs are gradually acclimated to this water-land ecotone, tending to form substantial root systems for improving erosion resistance. Accompanying rhizosphere microzone plays crucial but unclear roles in methylmercury (MeHg) formation in the WLFZ. Thus, we conducted this study in the WLFZ of the Three Gorges Reservoir, to explore effects of the rhizosphere of a dominant flooding-tolerant herb (bermudagrass) on MeHg production. The elevated Hg and MeHg in rhizosphere soils suggest that the rhizosphere environment provides favorable conditions for Hg accumulation and methylation. The increased bioavailable Hg and microbial activity in the rhizosphere probably serve as important factors driving MeHg formation in the presence of bermudagrass. Simultaneously, the rhizosphere environments changed the richness, diversity, and distribution of hgcA-containing microorganisms. Here, a typical iron-reducing bacterium (Geobacteraceae) has been screened, however, the majority of hgcA genes detected in rhizosphere, near-, and non-rhizosphere soils of the WLFZ were unclassified. Collectively, these results provide new insights into the elevated MeHg production as related to microbial processes in the rhizosphere of perennial herbs in the WLFZ, with general implications for Hg cycling in other ecosystems with water-level fluctuations.
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Affiliation(s)
- Juan Wang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yuping Xiang
- Laboratory of Environmental Nanotechnology & Health Effect, Chinese Academy of Sciences, Research Center for Eco-Environmental Sciences, Beijing 100085, China
| | - Xiaosong Tian
- College of Resources and Safety, Chongqing Vocational Institute of Engineering, Chongqing 402260, China
| | - Cheng Zhang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Guiqing Gong
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Jinping Xue
- Institut des Sciences Analytiques et des Physico-Chimie pour l'Environnement et les Matériaux (IPREM), UMR 5254, CNRS, Université de Pau et des Pays de l'Adour, Pau 64000, France
| | - Tao Jiang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Dingyong Wang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China.
| | - Yongmin Wang
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China.
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10
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Baptista-Salazar C, Quadra GR, Sobek A, Jonsson S. Insights into the factors influencing mercury concentrations in tropical reservoir sediments. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1542-1553. [PMID: 34524328 PMCID: PMC8528188 DOI: 10.1039/d1em00156f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Thousands of dams are currently under construction or planned worldwide to meet the growing need for electricity. The creation of reservoirs could, however, lead to conditions that promote the accumulation of mercury (Hg) in surface sediments and the subsequent production of methylmercury (MeHg). Once produced, MeHg can bioaccumulate to harmful levels in organisms. It is unclear to what extent variations in physical features and biogeochemical factors of the reservoir impact Hg accumulation. The objective of this study was to identify key drivers of the accumulation of total Hg (THg) in tropical reservoir sediments. The concentration of THg in all analyzed depth intervals of 22 sediment cores from the five contrasting reservoirs investigated ranged from 16 to 310 ng g-1 (n = 212, in the different sediment cores, the maximum depth varied from 18 to 96 cm). Our study suggests reservoir size to be an important parameter determining the concentration of THg accumulating in tropical reservoir sediments, with THg ranging up to 50 ng g-1 in reservoirs with an area exceeding 400 km2 and from 100 to 200 ng g-1 in reservoirs with an area less than 80 km2. In addition to the reservoir size, the role of land use, nutrient loading, biome and sediment properties (e.g., organic carbon content) was tested as potential drivers of THg levels. The principal component analysis conducted suggested THg to be related to the properties of the watershed (high degree of forest cover and low degree of agricultural land use), size and age of the reservoir, water residence time and the levels of nutrients in the reservoir. A direct correlation between THg and tested variables was, however, only observed with the area of the reservoir.
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Affiliation(s)
| | - Gabrielle R Quadra
- Laboratório de Ecologia Aquática, Programa de Pós-Graduação em Biodiversidade e Conservação da Natureza. Universidade Federal de Juiz de Fora, 36036 900, Juiz de Fora, Brazil
| | - Anna Sobek
- Department of Environmental Science, Stockholm University, 106 91 Stockholm, Sweden.
| | - Sofi Jonsson
- Department of Environmental Science, Stockholm University, 106 91 Stockholm, Sweden.
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11
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Xu Y, He T, Wu P, Yin D, Ran S. Fulvic acid: A key factor governing mercury bioavailability in a polluted plateau wetland. WATER RESEARCH 2021; 205:117652. [PMID: 34583206 DOI: 10.1016/j.watres.2021.117652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/01/2021] [Accepted: 09/04/2021] [Indexed: 06/13/2023]
Abstract
Fulvic acids (FAs) are known to regulate the fate of mercury (Hg) in sediments, but the key effects of their properties are still unclear. In this study, field investigations and simulation experiments were conducted in a heavy metal-polluted wetland to identify FA characteristics and their association with the production and bioaccumulation of methylmercury (MeHg). Compared to permanently inundated areas (PIA), seasonally inundated areas (SIAs) had lower total Hg levels in sediments, whereas higher MeHg levels in sediments (0.20 ± 0.09 ng g-1 vs. 0.55 ± 0.31 ng g-1) and benthos (0.25 ± 0.22 ng g-1 vs. 1.62 ± 1.78 ng g-1). Meanwhile, the THg and MeHg concentrations in the same macrophyte species between PIA and SIA also followed a similar rule with benthos. FA-bound Hg in the sediment was significantly correlated with MeHg in the sediment (p < 0.01), as well as THg and MeHg in benthos (p < 0.05), indicating that FAs have the capacity to promote MeHg production and bioaccumulation. Moreover, the FAs in the sediments of the SIA had lower fractions and alkyl C/O-alkyl C ratios, but higher molecular weights and THg/MeHg concentrations than those in the PIA, indicating that FAs in SIA have increased bioavailability and enhanced competition for Hg, favoring significantly elevated FA-bound Hg levels. Biological exposure testing further demonstrated that FAs extracted from SIA had a greater ability to increase the production and bioaccumulation of MeHg than those extracted from PIA. Overall, these results highlight that the molecular composition and sources of FAs, excluding their concentrations, are one of important factors responsible for the obvious spatial heterogeneity of MeHg in sediments and aquatic organisms in the wetland.
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Affiliation(s)
- Yiyuan Xu
- College of Resources and Environment Engineering, Guizhou University, Guiyang 550025, China
| | - Tianrong He
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment Engineering, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China.
| | - Pan Wu
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment Engineering, Guizhou University, Guiyang 550025, China
| | - Deliang Yin
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment Engineering, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China.
| | - Shu Ran
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China
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12
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Ni FJ, Bhavsar SP, Poirier D, Branfireun B, Petro S, Arts MT, Chong-Kit R, Mitchell CPJ, Arhonditsis GB. Impacts of water level fluctuations on mercury concentrations in hydropower reservoirs: A microcosm experiment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 220:112354. [PMID: 34116335 DOI: 10.1016/j.ecoenv.2021.112354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 04/02/2021] [Accepted: 05/15/2021] [Indexed: 06/12/2023]
Abstract
Hydropower generation, a renewable source of electricity, has been linked to elevated methylmercury (MeHg) concentrations in impoundments and aquatic biota. This study investigates the impact of water level fluctuations (WLF) on MeHg concentrations in water, sediment, and fish. Using a set of controlled microcosm experiments emulating the drawdown/refill dynamics and subsequent sediment exposure to air experienced in reservoirs, we demonstrate that less frequent WLFs, and/or increased exposure of sediment to air, can lead to elevated MeHg concentrations in sediment, and total mercury (THg) and MeHg concentrations in water. In examining the effects of WLF frequency (two-day, weekly, and monthly), the monthly treatment displayed the highest THg and MeHg water levels, while the weekly treatment was characterized by the highest MeHg levels in the sediment. Our work supports emerging evidence that longer duration between WLF creates a larger surface area of sediment exposed to air leading to conditions conducive to higher MeHg concentrations in sediments and water. In contrast, THg, MeHg, and fatty acid trends in fish were largely inconclusive characterized by similar among-treatment effects and minimal temporal variability over the course of our experiment. This result could partly be attributed to overall low mercury levels and simple "worm-forage fish" food web in our experiment. To elucidate the broader impacts of water fluctuations on aquatic chemistry and biota, other factors (e.g., longer WLF cycles, dissolved organic matter, temperature, more complex food webs) which modulate both methylation rates and food web dynamics must be considered.
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Affiliation(s)
- Felicity J Ni
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Satyendra P Bhavsar
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada; Ontario Ministry of Environment, Conservation, and Parks, Toronto, Ontario M9P 3V6, Canada.
| | - David Poirier
- Ontario Ministry of Environment, Conservation, and Parks, Toronto, Ontario M9P 3V6, Canada
| | - Brian Branfireun
- Department of Biology and Centre for Environment & Sustainability, Western University, London, Ontario N6A 3K7, Canada
| | - Steve Petro
- Ontario Ministry of Environment, Conservation, and Parks, Toronto, Ontario M9P 3V6, Canada
| | - Michael T Arts
- Department of Chemistry & Biology, Ryerson University, Toronto, Ontario M5B 2K3, Canada
| | - Richard Chong-Kit
- Ontario Ministry of Environment, Conservation, and Parks, Toronto, Ontario M9P 3V6, Canada
| | - Carl P J Mitchell
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - George B Arhonditsis
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada.
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13
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Janssen SE, Hoffman JC, Lepak RF, Krabbenhoft DP, Walters D, Eagles-Smith CA, Peterson G, Ogorek JM, DeWild JF, Cotter A, Pearson M, Tate MT, Yeardley RB, Mills MA. Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 779:146284. [PMID: 33744580 PMCID: PMC9563104 DOI: 10.1016/j.scitotenv.2021.146284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/01/2021] [Accepted: 03/01/2021] [Indexed: 05/12/2023]
Abstract
Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human and wildlife health. Mercury (Hg) is a contaminant of concern in many of these highly urbanized and industrialized coastal regions, one of which is the Saint Louis River estuary (SLRE), the second largest tributary to Lake Superior. The SLRE has legacy Hg contamination that drives high Hg concentrations within sediments, but it is unclear whether legacy-derived Hg actively cycles within the food web. To understand the relative contributions of legacy versus contemporary Hg sources in coastal zones, Hg, carbon, and nitrogen stable isotope ratios were measured in sediments and food webs of SLRE and the Bad River, an estuarine reference site. Hg stable isotope values revealed that legacy contamination of Hg was widespread and heterogeneously distributed in sediments of SLRE, even in areas lacking industrial Hg sources. Similar isotope values were found in benthic invertebrates, riparian spiders, and prey fish from SLRE, confirming legacy Hg reaches the SLRE food web. Direct comparison of prey fish from SLRE and the Bad River confirmed that Hg isotope differences between the sites were not attributable to fractionation associated with rapid Hg bioaccumulation at estuarine mouths, but due to the presence of industrial Hg within SLRE. The Hg stable isotope values of game fish in both estuaries were dependent on fish migration and diet within the estuaries and extending into Lake Superior. These results indicate that Hg from legacy contamination is actively cycling within the SLRE food web and, through migration, this Hg also extends into Lake Superior via game fish. Understanding sources and the movement of Hg within the estuarine food web better informs restoration strategies for other impaired Great Lakes coastal zones.
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Affiliation(s)
- Sarah E Janssen
- U.S. Geological Survey Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA.
| | - Joel C Hoffman
- U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA
| | - Ryan F Lepak
- U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA; Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Street, Madison, WI 53706, USA
| | - David P Krabbenhoft
- U.S. Geological Survey Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA
| | - David Walters
- U.S. Geological Survey Columbia Environmental Research Center, 4200 New Haven Rd, Columbia, MO 65201, USA
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 3200SW Jefferson Way, Corvallis, OR 97331, USA
| | - Greg Peterson
- U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA
| | - Jacob M Ogorek
- U.S. Geological Survey Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA
| | - John F DeWild
- U.S. Geological Survey Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA
| | - Anne Cotter
- U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA
| | - Mark Pearson
- U.S. Environmental Protection Agency Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA
| | - Michael T Tate
- U.S. Geological Survey Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA
| | - Roger B Yeardley
- U.S. Environmental Protection Agency Office of Research and Development, Center for Environmental Solutions and Emergency Response, Cincinnati, OH 45220, USA
| | - Marc A Mills
- U.S. Environmental Protection Agency Office of Research and Development, Center for Environmental Solutions and Emergency Response, Cincinnati, OH 45220, USA
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14
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Huang S, Zhao Y, Lv S, Wang W, Wang W, Zhang Y, Huo Y, Sun X, Chen Y. Distribution of mercury isotope signatures in Yundang Lagoon, Xiamen, China, after long-term interventions. CHEMOSPHERE 2021; 272:129716. [PMID: 33601205 DOI: 10.1016/j.chemosphere.2021.129716] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/14/2021] [Accepted: 01/17/2021] [Indexed: 05/24/2023]
Abstract
Isotope signatures of mercury (Hg) were determined for Hg fractions in seawater, sediments, porewaters, core sediments and fish from the Yundang Lagoon, Xiamen, China. Sequential extraction was used to extract Hg fractions in sediments and the purge-trap method was used to preconcentrate Hg in seawater. A large variation in mass dependent fractionation (δ202Hg: -2.50‰ to -0.36‰) was observed in the lagoon. Seawater and fish samples showed positive mass-independent fractionation (Δ199Hg: -0.06‰-0.45‰), while most of sediment and porewater samples displayed insignificant mass-independent fractionation (Δ199Hg: -0.10‰-0.07‰). Ancillary parameters (total organic carbon, sulfide, pH, Eh, water content and grain size) were also measured in the sediments to investigate correlations with Hg isotopes. Three sources (domestic sewage, sediments and atmospheric deposition) were identified as the main sources of Hg in the lagoon seawater. Photochemical reaction was the main process causing isotope fractionation in seawater. Through Hg partitioning and deposition, light isotopes were enriched from dissolved Hg to particulate Hg, then to sediments, and then to porewaters. Finally, Hg isotope signatures were used to identify the Hg sources and fractionation processes in core sediments from different depths. Our results demonstrate that Hg isotopes are powerful tools for tracing Hg sources and arriving at a better understanding of Hg biogeochemical cycling in the lagoon after long-term interventions.
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Affiliation(s)
- Shuyuan Huang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Yuhan Zhao
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Supeng Lv
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Weiguo Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Weili Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Yuanbiao Zhang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China.
| | - Yunlong Huo
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Xiuwu Sun
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Yaojin Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
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15
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Xiang Y, Liu G, Yin Y, Cai Y. Periphyton as an important source of methylmercury in Everglades water and food web. JOURNAL OF HAZARDOUS MATERIALS 2021; 410:124551. [PMID: 33223320 DOI: 10.1016/j.jhazmat.2020.124551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/23/2020] [Accepted: 11/10/2020] [Indexed: 06/11/2023]
Abstract
Periphyton is ubiquitous in Florida Everglades and has a profound effect on mercury (Hg) cycling. Enhanced methylmercury (MeHg) production in periphyton has been well documented, but the re-distribution of MeHg from periphyton remains unknown. In this study, periphyton, sediments, surface water, periphyton overlying water, and periphyton porewater were collected from Everglades for analyzing the distribution of MeHg and total Hg (THg). Results showed that there were no significant differences in THg and MeHg in different types of periphyton, but they all displayed higher MeHg levels than sediments. MeHg distribution coefficients (logkd) in periphyton were lower than in sediments, suggesting that periphyton MeHg could be more labile entering aquatic cycling and bioaccumulation. In water, the more the distance of water samples taken from periphyton, the lower the MeHg and dissolved organic carbon concentrations were detected. In extracellular polymeric substances of periphyton, MeHg in colloidal fractions was significantly higher than that in capsular fractions. It was estimated that approximately 10% (or 1.35 kg) of periphyton MeHg were passed on to mosquitofish entering the food web during wet season, contributing 73% of total Hg stocked in mosquitofish. These results revealed the importance of periphyton on water MeHg distribution and MeHg bioaccumulation in Everglades.
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Affiliation(s)
- Yuping Xiang
- Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL 33199, USA; Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guangliang Liu
- Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL 33199, USA
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yong Cai
- Department of Chemistry & Biochemistry and Southeast Environmental Research Center, Florida International University, 11200 SW 8th ST, Miami, FL 33199, USA; Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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16
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Larson JH, Maki RP, Christensen VG, Hlavacek EJ, Sandheinrich MB, LeDuc JF, Kissane C, Knights BC. Mercury and water level management in lakes of northern Minnesota. Ecosphere 2021. [DOI: 10.1002/ecs2.3465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- James H. Larson
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse Wisconsin54603USA
| | - Ryan P. Maki
- National Park Service Voyageurs National Park International Falls Minnesota56649USA
| | | | - Enrika J. Hlavacek
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse Wisconsin54603USA
| | - Mark B. Sandheinrich
- River Studies Center University of Wisconsin‐La Crosse La Crosse Wisconsin54601USA
| | - Jaime F. LeDuc
- National Park Service Voyageurs National Park International Falls Minnesota56649USA
| | - Claire Kissane
- National Park Service Voyageurs National Park International Falls Minnesota56649USA
| | - Brent C. Knights
- U.S. Geological Survey Upper Midwest Environmental Sciences Center La Crosse Wisconsin54603USA
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17
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Ferreira-Rodríguez N, Castro AJ, Tweedy BN, Quintas-Soriano C, Vaughn CC. Mercury consumption and human health: Linking pollution and social risk perception in the southeastern United States. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 282:111528. [PMID: 33172704 DOI: 10.1016/j.jenvman.2020.111528] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/17/2020] [Accepted: 10/18/2020] [Indexed: 06/11/2023]
Abstract
The study of the relationships between freshwater organisms, pollution and public awareness has been little researched. The public's perception of risk from pollution is a fundamental component in determining consumer behavior and promoting healthy habits. For instance, understanding how consumers perceive the risks associated with pollution can help with adoption of safe behaviors to reduce the health hazard associated with pollutant exposure. This study focused on the southeastern United States, a region predicted to be exposed to high mercury stress by increasing mercury deposition and methylation. First, we placed our study region in the world map of regions more prone to suffer from increasing mercury stress in a climate change scenario. Second, mercury levels in fish tissues was quantified by direct mercury analyzer (DMA). Third, we explored human fish consumption habits and risk social perception, including willingness to adapt fish consumption based on two future hypothetical scenarios of mercury stress. From a global perspective, our analysis demonstrates that the southern US is one of five world areas of greatest conservation concern for mercury stress. In this region, the average mono-methyl mercury concentration in fish tissues exceeded the limits considered safe for human consumption. Even though many in the local population were aware of the health hazards associated with fish consumption, only women of reproductive age were willing to adopt safe consumption habits. Altogether, these results show how bringing together field data, social perceptions, and consumption habits can help in designing an adaptive strategy to confront mercury pollution. Although our results are for the United States, other world regions prone to suffer increasing mercury stress have been identified and should be the focus of future studies and prescriptions.
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Affiliation(s)
- Noé Ferreira-Rodríguez
- Departamento de Ecoloxía e Bioloxía Animal, Facultade de Bioloxía, Campus As Lagoas - Marcosende, Universidade de Vigo, Vigo, 36310, Spain.
| | - Antonio J Castro
- Departmento de Biología y Geología, Centro Andaluz para la Evaluación y Seguimiento del Cambio Global, University of Almeria, 04120, Almería, Spain; Department of Biological Sciences, Idaho State University, 921 South 8th Avenue, Pocatello, ID, 83209, USA; Oklahoma Biological Survey and Department of Biology, University of Oklahoma, 111 E Chesapeake Street, Norman, OK, 73019, USA
| | - Beth N Tweedy
- Oklahoma Biological Survey and Department of Biology, University of Oklahoma, 111 E Chesapeake Street, Norman, OK, 73019, USA; Bizzell Memorial Library, University of Oklahoma, 401 W. Brooks St, Norman, OK, 73019, USA
| | - Cristina Quintas-Soriano
- Departmento de Biología y Geología, Centro Andaluz para la Evaluación y Seguimiento del Cambio Global, University of Almeria, 04120, Almería, Spain; Social-Ecological Interactions in Agricultural Systems Lab, Faculty of Organic Agricultural Sciences, University of Kassel, Steinstraße 19, 37213, Witzenhausen, Germany
| | - Caryn C Vaughn
- Oklahoma Biological Survey and Department of Biology, University of Oklahoma, 111 E Chesapeake Street, Norman, OK, 73019, USA
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Seelos M, Beutel M, Austin CM, Wilkinson E, Leal C. Effects of hypolimnetic oxygenation on fish tissue mercury in reservoirs near the new Almaden Mining District, California, USA. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115759. [PMID: 33120343 DOI: 10.1016/j.envpol.2020.115759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/23/2020] [Accepted: 09/27/2020] [Indexed: 06/11/2023]
Abstract
Almaden, Calero, and Guadalupe reservoirs (San Jose, CA, USA) are small (<13 million m3) surface water reservoirs polluted by the former New Almaden Mining District, North America's most productive historical mercury (Hg) mine. Stevens Creek Reservoir (Cupertino, CA, USA) also has elevated fish Hg concentrations, but no historical mining source. We report a 15-year dataset to evaluate the effectiveness of line diffuser hypolimnetic oxygenation systems (HOSs) in reducing methylmercury (MeHg) concentrations in reservoir water and fish after four consecutive years of operation. HOSs were installed in each reservoir to increase dissolved oxygen concentrations in bottom water, thereby suppressing the activity of anaerobic bacteria (e.g., sulfate-reducing bacteria) known to produce MeHg. Before HOS operation, MeHg concentrations increased in bottom waters of all four reservoirs during periods of thermal stratification and profundal hypoxia. MeHg concentrations decreased significantly in bottom waters during HOS operation, with mean reductions of 63%-85% below pre-oxygenation concentrations. However, MeHg concentrations were unchanged or increased in surface waters. This could be the result of enhanced mixing between surface and bottom waters as a result of line diffuser oxygenation, or continued Hg methylation occurring in the oxic water column and littoral sediments. Despite little change in whole water column MeHg concentrations, we observed modest but significant declining trends in fish tissue Hg in Guadalupe and Stevens Creek reservoirs. Results suggest that oxygenation, rather than directly lowering MeHg in water, may have mixed nutrients into surface waters, thereby enhancing primary productivity and indirectly affecting Hg bioaccumulation by diluting concentrations in phytoplankton.
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Affiliation(s)
- Mark Seelos
- Valley Water, San Jose, CA, 95118, USA; Environmental Systems Graduate Program, University of California Merced, Merced, CA, 95343, USA.
| | - Marc Beutel
- Environmental Systems Graduate Program, University of California Merced, Merced, CA, 95343, USA
| | - Carrie M Austin
- San Francisco Bay Regional Water Quality Control Board, Oakland, CA, 94612, USA
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19
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Wang T, Driscoll CT, Hwang K, Chandler D, Montesdeoca M. Total and methylmercury concentrations in ground and surface waters in natural and restored freshwater wetlands in northern New York. ECOTOXICOLOGY (LONDON, ENGLAND) 2020; 29:1602-1613. [PMID: 31974921 DOI: 10.1007/s10646-019-02155-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Nearly half of freshwater wetlands have been lost due to human disturbance. In response, wetlands are being restored to retain their ecosystem services. A potentially adverse consequence of wetland function is the production of methylmercury (MeHg). We measured concentrations of mercury (Hg) species and ancillary parameters in groundwaters and surface waters from four natural and 16 restored wetlands in northern New York State, USA to investigate differences in concentrations of Hg species among wetlands. We found no obvious differences in concentrations of total mercury (THg) and methylmercury in pond waters between natural and restored wetlands. High values of %methylmercury were evident in both ground (38.8 ± 27.6%) and surface waters (43.4 ± 25.6%) suggesting these wetland complexes are highly efficient in converting ionic Hg to methylmercury, regardless if restored or natural. High methylation efficiency may be due to observed drying and rewetting cycles. Hg in pond waters is likely derived from direct atmospheric deposition or by mobilization from near-wetland shallow sediments, in addition to groundwater inflows. Water flow of groundwaters from the associated watershed into pond waters resulted in increases in concentrations of THg and methylmercury. Dissolved organic matter likely plays an important role in the supply of Hg to pond waters. Relationships between methylmercury and %methylmercury with sulfate and nitrate in groundwaters may suggest some chemical limitation on Hg methylation at higher concentrations of these anions. Because of the similarity in Hg dynamics for natural and restored wetlands, the most effective strategy to mitigate methylmercury production would be to decrease atmospheric Hg deposition.
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Affiliation(s)
- Ting Wang
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, NY, 13244, USA.
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, NY, 13244, USA
| | - Kyotaek Hwang
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, NY, 13244, USA
| | - David Chandler
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, NY, 13244, USA
| | - Mario Montesdeoca
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, NY, 13244, USA
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20
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Yin D, Peng F, He T, Xu Y, Wang Y. Ecological risks of heavy metals as influenced by water-level fluctuations in a polluted plateau wetland, southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140319. [PMID: 32634688 DOI: 10.1016/j.scitotenv.2020.140319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
The Caohai wetland, one of karst plateau wetlands in southwest China, is given more attention due to the serious heavy metal (HM) pollution from artisanal zinc smelting activities. A natural hydrological change has caused this wetland to form a water-level fluctuating zone. This raises a question of whether such an area has elevated HM risks to the aquatic environment, and it was explored by a field investigation and biological exposure experiment. The results showed that Caohai sediment properties were significantly altered by water-level fluctuation, and the permanently inundated sediment had obviously higher organic matter (SOM) concentrations (32.62 ± 9.37%), humification levels (ratio of C to H, 6.81 ± 0.97), and Fe oxide fractions (12.29 ± 3.17%) than seasonally inundated sediment (4.94 ± 2.25%, 1.33 ± 0.75, and 8.72 ± 1.87%, respectively). These significantly enhanced the competition and retention, resulting in the increased accumulation, whereas reduced bioavailability of HMs. In comparison, the mean bioaccumulation capacity of Zn, Pb and Cd by wild benthos at the seasonally inundated area respectively increased by 2, 11 and 20 times higher than that at the permanently inundated area, which was further verified in the biological incubation experiment. Our results suggest that hydraulic fluctuation can greatly shape the sediment properties to increase the ecological risks of HMs to organisms.
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Affiliation(s)
- Deliang Yin
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China
| | - Fengcheng Peng
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China
| | - Tianrong He
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment, Guizhou University, Guiyang 550025, China; Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025, China.
| | - Yiyuan Xu
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guizhou University, Guiyang 550025, China; College of Resources and Environment, Guizhou University, Guiyang 550025, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
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21
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Gustin MS, Bank MS, Bishop K, Bowman K, Branfireun B, Chételat J, Eckley CS, Hammerschmidt CR, Lamborg C, Lyman S, Martínez-Cortizas A, Sommar J, Tsui MTK, Zhang T. Mercury biogeochemical cycling: A synthesis of recent scientific advances. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:139619. [PMID: 32783819 PMCID: PMC7430064 DOI: 10.1016/j.scitotenv.2020.139619] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 05/23/2023]
Abstract
The focus of this paper is to briefly discuss the major advances in scientific thinking regarding: a) processes governing the fate and transport of mercury in the environment; b) advances in measurement methods; and c) how these advances in knowledge fit in within the context of the Minamata Convention on Mercury. Details regarding the information summarized here can be found in the papers associated with this Virtual Special Issue of STOTEN.
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Affiliation(s)
- Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89439, USA.
| | - Michael S Bank
- Department of Contaminants and Biohazards, Institute of Marine Research, Bergen, Norway; Department of Environmental Conservation, University of Massachusetts, Amherst, MA 01255, USA
| | - Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden
| | - Katlin Bowman
- Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA; University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Brian Branfireun
- Department of Biology and Centre for Environment and Sustainability, Western University, London, Canada
| | - John Chételat
- Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, ON K1A 0H3, Canada
| | - Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101, USA
| | - Chad R Hammerschmidt
- Wright State University, Department of Earth and Environmental Sciences, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Carl Lamborg
- University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Seth Lyman
- Bingham Research Center, Utah State University, 320 N Aggie Blvd., Vernal, UT, USA
| | - Antonio Martínez-Cortizas
- EcoPast (GI-1553), Facultade de Bioloxía, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Tong Zhang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China
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22
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Baldwin AK, Poulin BA, Naymik J, Hoovestol C, Clark GM, Krabbenhoft DP. Seasonal Dynamics and Interannual Variability in Mercury Concentrations and Loads through a Three-Reservoir Complex. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9305-9314. [PMID: 32667810 DOI: 10.1021/acs.est.9b07103] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Hells Canyon Complex (HCC) along the Snake River (Idaho-Oregon border, U.S.A.) encompasses three successive reservoirs that seasonally stratify, creating anoxic conditions in the hypolimnion that promote methylmercury (MeHg) production. This study quantified seasonal dynamics and interannual variability in mercury concentrations (inorganic divalent mercury (IHg) and MeHg) and loads at four reservoir inflow and outflow locations through the HCC (2014-2017). We observed (1) that the HCC is a net sink for both IHg and MeHg, (2) interannual variability in IHg and MeHg loads largely reflecting streamflow conditions, and (3) seasonal variability in particulate IHg loading at the inflow (greatest from February to April) and MeHg export from the outflow (greatest from September to December) of the HCC. Seasonal export of MeHg was evidenced by increases in monthly mean concentrations of unfiltered MeHg (approximately 2-fold) and the percentage of total mercury (THg) as MeHg (≥4-fold) coincident with reservoir destratification. Despite evidence of seasonal export of MeHg from the HCC, annual loads indicate a 42% decrease in unfiltered MeHg from HCC inflow to outflow. Results from this study improve the understanding of seasonal variability in mercury transport through and transformation within a reservoir complex.
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Affiliation(s)
- Austin K Baldwin
- U.S. Geological Survey, 230 Collins Road, Boise, Idaho 83702, United States
| | - Brett A Poulin
- U.S. Geological Survey, 3215 Marine Street, Suite E127, Boulder, Colorado 80303, United States
- Department of Environmental Toxicology, University of California Davis, 1 Shields Avenue, Davis, CA 95616, United States
| | - Jesse Naymik
- Idaho Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Charles Hoovestol
- Idaho Power Company, 1221 West Idaho Street, Boise, Idaho 83702, United States
| | - Gregory M Clark
- U.S. Geological Survey, 230 Collins Road, Boise, Idaho 83702, United States
| | - David P Krabbenhoft
- U.S. Geological Survey, 8505 Research Way, Middleton, Wisconsin 53562, United States
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23
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Liu J, Wang D, Zhang J, Liem-Nguyen V, Huang R, Jiang T. Evaluation of Hg methylation in the water-level-fluctuation zone of the Three Gorges Reservoir region by using the MeHg/Hg T ratio. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 195:110468. [PMID: 32200146 DOI: 10.1016/j.ecoenv.2020.110468] [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: 12/16/2019] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 06/10/2023]
Abstract
In the recent decade, the hydroelectric reservoir is identified as a methylmercury (MeHg) hotspot and gained much attention. The artificial water level management in the Three Gorges Reservoir (TGR) in China formed a water-level-fluctuation zone (WLFZ) undergoing flooding drying rotations annually. However, the mercury (Hg) methylation and major geochemical driving factors at different elevations in the WLFZ remain unclear. Here we use total Hg (HgT) normalized MeHg (MeHg/HgT ratio) to evaluate Hg methylation degree in a one-year field study at 155, 165 m elevations in the WLFZ and with >175 m elevation as the reference. Results demonstrate that MeHg/HgT ratio at the WLFZ could reach 4.1% in soils, and both 155 and 165 m elevations have a higher Hg methylation degree than the >175 m elevation. However, the differences in MeHg/HgT ratios both in soils and waters between 155 and 165 m elevations are not significant. This indicates the influence of different submerging periods on the MeHg/HgT at the WLFZ elevations is not observed. The significant correlation between the MeHg/HgT ratio and soil organic carbon (SOC) content implies a MeHg retention in re-exposed soils after flooding. Decoupling of MeHg/HgT ratios between submerged soil and overlying water are found at both elevations and therefore make MeHg/HgT in waters alone cannot be used to evaluate Hg methylation degree in this study. The calculation of HgT and MeHg partitioning coefficient (Kd) found an immobilization of MeHg by submerged soils at the WLFZ during the flooding period. Major geochemical factors, determined through principal component analysis (PCA), in affecting Hg methylation are the redox cycling of sulfur and the distribution of organic matters in the WLFZ.
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Affiliation(s)
- Jiang Liu
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China; Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
| | - Dingyong Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
| | - Jinzhong Zhang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
| | - Van Liem-Nguyen
- Laboratory of Advanced Materials Chemistry, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
| | - Rong Huang
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, 400716, China.
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24
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Xie M, Zhang C, Liao X, Huang C. The influence of wetting-drying alternation on methylmercury degradation in Guangzhou soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 259:113866. [PMID: 31891907 DOI: 10.1016/j.envpol.2019.113866] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
In one of our previous studies, the mechanisms of radical-initiated methylmercury (MeHg) degradation in soil with coexisting Fe and Cu have been reported. In this work, various environmental factors, including water table fluctuation, pH and major ions, are discussed to clarify the behavior of MeHg in subsurface environments. Soil column experiments were set up to simulate the degradation of MeHg in the soil with an iron-bearing mineral (annite), which has often undergone repeating wetting-drying cycles, resulting from the local climate. The results indicate that wetting-drying alternation can initiate MeHg degradation in the soil with the annite mineral. Additionally, the majority of the major ions (K+, Na+, Mg2+, Fe3+, Cl-, SO42-, NO3-) in the interstitial soil had little effect in the degradation of MeHg with the exception of Cu, which improved the degradation depending on the pH. At acidic pHs Cu increased the production of hydroxyl radical while at more alkaline pHs there was oxidation to Cu(III). The products including Hg(II) and Hg(0) of MeHg degradation were also identified in this work. This study reveals that the geochemical cycle of MeHg is closely linked to local climate and pedosphere processes.
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Affiliation(s)
- Mengying Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China
| | - Caixiang Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China.
| | - Xiaoping Liao
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, 430074, PR China
| | - Changsheng Huang
- Wuhan Center of China Geological Survey, Wuhan, 430205, Hubei, China
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25
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Du H, Sun T, Wang D, Ming M. Bacterial and archaeal compositions and influencing factors in soils under different submergence time in a mercury-sensitive reservoir. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 191:110155. [PMID: 31972452 DOI: 10.1016/j.ecoenv.2019.110155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/27/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Soils in the water-level-fluctuating zone (WLFZ) of Three Gorges Reservoir (TGR) inundated by water for different periods of time are confirmed to have disparate characteristics to mercury (Hg), and thus it is of great significance to further investigate microbial compositions and influencing factors. The objective of this study was to compare bacterial and archaeal richness, α-diversities and compositions, as well as affecting variables, especially Hg concentrations, among soils under different submergence time-SI (inundated soil), SS (semi-inundated soil), SN(non-inundated soil) and SSe (sediment)-based on high throughput sequencing. Results showed that sediment had significantly higher bacterial and archaeal richness and α-diversities than the other soil types. Anaerolinea and Aeromonas, as well as Altiarchaeales, Nitrosoarchaeum, and Methanosarta were dominant in SSe, while sharply decreasing in the other soil types, with significant difference among groups. An unclassified genus in SCG critically predominating in SI, SS and SN, drastically reduced in SSe, with extremely significant difference among groups. Bathyarchaeota and Nitrososphaera, both dominating in SSe, decreased dramatically and almost vanished in SI and SN. All the variables except pH posed a significant positive effect on bacterial and archaeal compositions in SSe, while opposite effect in the other three soil types. MeHg and THg concentrations had relatively weaker effects on microbial compositions comparing to variables like NH4+, CEC, OM and SO42+.
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Affiliation(s)
- Hongxia Du
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Bioresource for Bioenergy, Southwest University, Chongqing, 400715, China
| | - Tao Sun
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Ma Ming
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Key Laboratory of Bioresource for Bioenergy, Southwest University, Chongqing, 400715, China.
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26
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Eckley CS, Gilmour CC, Janssen S, Luxton TP, Randall PM, Whalin L, Austin C. The assessment and remediation of mercury contaminated sites: A review of current approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136031. [PMID: 31869604 PMCID: PMC6980986 DOI: 10.1016/j.scitotenv.2019.136031] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/07/2019] [Accepted: 12/07/2019] [Indexed: 04/13/2023]
Abstract
Remediation of mercury (Hg) contaminated sites has long relied on traditional approaches, such as removal and containment/capping. Here we review contemporary practices in the assessment and remediation of industrial-scale Hg contaminated sites and discuss recent advances. Significant improvements have been made in site assessment, including the use of XRF to rapidly identify the spatial extent of contamination, Hg stable isotope fractionation to identify sources and transformation processes, and solid-phase characterization (XAFS) to evaluate Hg forms. The understanding of Hg bioavailability for methylation has been improved by methods such as sequential chemical extractions and porewater measurements, including the use of diffuse gradient in thin-film (DGT) samplers. These approaches have shown varying success in identifying bioavailable Hg fractions and further study and field applications are needed. The downstream accumulation of methylmercury (MeHg) in biota is a concern at many contaminated sites. Identifying the variables limiting/controlling MeHg production-such as bioavailable inorganic Hg, organic carbon, and/or terminal electron acceptors (e.g. sulfate, iron) is critical. Mercury can be released from contaminated sites to the air and water, both of which are influenced by meteorological and hydrological conditions. Mercury mobilized from contaminated sites is predominantly bound to particles, highly correlated with total sediment solids (TSS), and elevated during stormflow. Remediation techniques to address Hg contamination can include the removal or containment of Hg contaminated materials, the application of amendments to reduce mobility and bioavailability, landscape/waterbody manipulations to reduce MeHg production, and food web manipulations through stocking or extirpation to reduce MeHg accumulated in desired species. These approaches often rely on knowledge of the Hg forms/speciation at the site, and utilize physical, chemical, thermal and biological methods to achieve remediation goals. Overall, the complexity of Hg cycling allows many different opportunities to reduce/mitigate impacts, which creates flexibility in determining suitable and logistically feasible remedies.
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Affiliation(s)
- Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101, USA.
| | - Cynthia C Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 21037-0028, USA.
| | - Sarah Janssen
- USGS Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA.
| | - Todd P Luxton
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Paul M Randall
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
| | - Lindsay Whalin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
| | - Carrie Austin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
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27
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Yin D, Wang Y, Xiang Y, Xu Q, Xie Q, Zhang C, Liu J, Wang D. Production and migration of methylmercury in water-level-fluctuating zone of the Three Gorges Reservoir, China: Dual roles of flooding-tolerant perennial herb. JOURNAL OF HAZARDOUS MATERIALS 2020; 381:120962. [PMID: 31442691 DOI: 10.1016/j.jhazmat.2019.120962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/29/2019] [Accepted: 08/02/2019] [Indexed: 06/10/2023]
Abstract
Water-level-fluctuating zone (WLFZ) is a prevalent water-land ecotone favorable for mercury (Hg) methylation. The succession of flooding tolerance plants in WLFZ gradually changes the landscape, and also brings a new question worth understanding whether these plants would enhance methylmercury (MeHg) production in WLFZ and increase risks to the aquatic environment. Given bermudagrass (Cynodon dactylon (L). Pers) as the dominant perennial herb with high flooding-tolerance in WLFZ of the Three Gorges Reservoir (TGR), we conducted a comprehensive study to investigate its roles in the production and migration of MeHg in WLFZ by field observations and stable isotope tracer experiments. Results showed that both elevated MeHg levels and Hg methylation rates appeared in soil/sediment in bermudagrass growing area, implying that the growth of bermudagrass could significantly enhance MeHg production. However, MeHg migration from sediment to water was restricted during the flooding period of the TGR, as obviously higher partitioning coefficients of MeHg between the sediment and porewater (p < 0.05) and lower MeHg release fluxes were observed in vegetated area, indicating that the presence of bermudagrass instead probably decreased the water MeHg level. Whereas, it is noteworthy that elevated MeHg in soil/sediment induced by the bermudagrass could pose potential risks to the benthos and further to the TGR food chain.
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Affiliation(s)
- Deliang Yin
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China.
| | - Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qinqin Xu
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qing Xie
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Cheng Zhang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Jiang Liu
- 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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28
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Sang C, Zheng Y, Zhou Q, Li D, Liang G, Gao Y. Effects of water impoundment and water-level manipulation on the bioaccumulation pattern, trophic transfer and health risk of heavy metals in the food web of Three Gorges Reservoir (China). CHEMOSPHERE 2019; 232:403-414. [PMID: 31158635 DOI: 10.1016/j.chemosphere.2019.04.216] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/28/2019] [Accepted: 04/29/2019] [Indexed: 05/20/2023]
Abstract
The Three Gorges Reservoir (TGR) of China, the largest hydropower project over the world, has attracted much attention to the water impoundment and water-level manipulation. In this study, we evaluated potential effects of water impoundment and seasonal water-level manipulation on the bioaccumulation, trophic transfer and health risk of HMs (Cu, Fe, Zn, Hg, Cd and Pb) in food web components (seston, aquatic invertebrate and fish) in TGR. Our results show that, after the impoundment for eight years (2003-2010), all of the six metal concentrations in aquatic biota fell within the criteria of safety quality guidelines. The concentrations of Cu, Fe, Zn and Hg in fish and aquatic invertebrates were higher than those before impoundment, whereas Cd and Pb were lower than those before impoundment. Nonetheless, Hg, Cd and Pb in aquatic consumers underwent an increasing trend during the entire impoundment, implying potential reservoir effect in the future. Only the concentrations of Hg, Cd and Pb in aquatic consumers exhibited a declining trend towards the dam, showing consistent with the background level at the three reaches. Seasonal variations in HM concentrations of fish and aquatic invertebrates were ascribed to the water-level manipulation associated with reservoir management. Our findings show that Hg or Cd biomagnified through aquatic food web during different hydrological periods, whereas Pb, Cu, Fe and Zn exhibited weak biomagnification power. Overall, Hg, Cd and Pb showed a higher risk than that of Cu, Fe and Zn.
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Affiliation(s)
- Chong Sang
- College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China
| | - Yuanyuan Zheng
- College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China
| | - Qiong Zhou
- College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China.
| | - Dapeng Li
- College of Fisheries, Huazhong Agricultural University, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Wuhan 430070, China; Hubei Provincial Engineering Laboratory for Pond Aquaculture, Wuhan 430070, China
| | - Gaodao Liang
- Wuhan Centers for Disease Prevention & Control, Wuhan 430015, China
| | - Yongwen Gao
- Makah Fisheries Management, P.O. Box 115, Neah Bay, WA 98357, USA
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29
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Qian Y, Cheng C, Drouillard K, Zhu Q, Feng H, He S, Fang Y, Qiao S, Kolenčíka M, Chang X. Bioaccumulation and growth characteristics of Vallisneria natans (Lour.) Hara after chronic exposure to metal-contaminated sediments. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:20510-20519. [PMID: 31102223 DOI: 10.1007/s11356-019-05347-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 04/29/2019] [Accepted: 05/01/2019] [Indexed: 06/09/2023]
Abstract
Metal-contaminated sediments in lakes is a global concern that poses toxicological risk to aquatic organisms. This study performed bioassays using the submerged macrophyte, Vallisneria natans (Lour.) Hara, exposed to contaminated sediments collected from five locations in Dianchi Lake, Yunnan, China. Among the sediments collected, Igeo showed enrichment of As and Cd in Dianchi Lake sediments. In spite of enriched toxic metals at some locations, laboratory bioassays found no significant difference in leaf biomass or leaf photosynthesis rate between the sites. Root biomass and root activity showed significant differences between locations and were negatively correlated with the concentration of As, Cd, Hg, and Pb in sediment but not related to Cr. The above correlations were strongest for Hg and As, respectively. Accumulation of Cd and Pb to leaves of bioassay plants was observed, but this was not evident for As and Cr. Overall, the results indicate that V. natans can be used as a bioassay organism and measures of root toxicity are sensitive to metal concentrations present in Dianchi Lake sediments. Furthermore, the study species holds promise for use as a biomonitor of Cd and Pb sediment metal content.
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Affiliation(s)
- Yu Qian
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China
| | - Changlei Cheng
- Analysis and Measurements Center of Yunnan Provincial Non-ferrous Geology Bureau, Kunming, 650051, Yunnan, China
| | - Ken Drouillard
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B3P4, Canada
| | - Qingzhi Zhu
- School of Marine and Atmospheric Science, State University of New York, Stony Brook, NY, 11794, USA
| | - Huan Feng
- Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ, 07043, USA
| | - Shuzhuang He
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China
| | - Yuhong Fang
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China
| | - Shinan Qiao
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China
| | - Marek Kolenčíka
- Department of Soil Science and Geology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture in Nitra, 94976, Nitra, Slovak Republic
| | - Xuexiu Chang
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China.
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Wang Y, Yin D, Xiang Y, Xu Q, Zhang C, Xie Q, Wang D. A Review of Studies on the Biogeochemical Behaviors of Mercury in the Three Gorges Reservoir, China. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 102:686-694. [PMID: 30859245 DOI: 10.1007/s00128-019-02586-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/02/2019] [Indexed: 06/09/2023]
Abstract
The Three Gorges Reservoir (TGR) is a relatively large reservoir, and its water level management actions produce a widespread water level fluctuation zone (WLFZ), which has characteristics of both terrestrial and aquatic ecosystems. Here, an integrated overview of current knowledge on Hg behaviors in the TGR, especially the WLFZ, as well as exposure risk to local residents was presented. Hg levels in the TGR were comparable with other natural aquatic systems. WLFZ in the TGR was confirmed to be an environment favorable for Hg methylation by enhancing microbial activity, promoting sulfur cycling and increasing the level of low-molecular-weight organic matters. However, elevated fish Hg concentrations did not follow the impoundment of TGR, indicating no obvious reservoir effect, while it is still noteworthy that frequently consuming fish is likely to be a methylmercury (MeHg) exposure pathway for specific populations e.g. fishermen around the TGR.
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Affiliation(s)
- Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, 400715, Chongqing, China
| | - Deliang Yin
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Qinqin Xu
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Cheng Zhang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, 400715, Chongqing, China
| | - Qing Xie
- College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China.
- Chongqing Key Laboratory of Agricultural Resources and Environment, 400715, Chongqing, China.
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Nogara PA, Oliveira CS, Schmitz GL, Piquini PC, Farina M, Aschner M, Rocha JBT. Methylmercury's chemistry: From the environment to the mammalian brain. Biochim Biophys Acta Gen Subj 2019; 1863:129284. [PMID: 30659885 DOI: 10.1016/j.bbagen.2019.01.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 12/14/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023]
Abstract
Methylmercury is a neurotoxicant that is found in fish and rice. MeHg's toxicity is mediated by blockage of -SH and -SeH groups of proteins. However, the identification of MeHg's targets is elusive. Here we focus on the chemistry of MeHg in the abiotic and biotic environment. The toxicological chemistry of MeHg is complex in metazoans, but at the atomic level it can be explained by exchange reactions of MeHg bound to -S(e)H with another free -S(e)H group (R1S(e)-HgMe + R2-S(e)H ↔ R1S(e)H + R2-S(e)-HgMe). This reaction was first studied by professor Rabenstein and here it is referred as the "Rabenstein's Reaction". The absorption, distribution, and excretion of MeHg in the environment and in the body of animals will be dictated by Rabenstein's reactions. The affinity of MeHg by thiol and selenol groups and the exchange of MeHg by Rabenstein's Reaction (which is a diffusion controlled reaction) dictates MeHg's neurotoxicity. However, it is important to emphasize that the MeHg exchange reaction velocity with different types of thiol- and selenol-containing proteins will also depend on protein-specific structural and thermodynamical factors. New experimental approaches and detailed studies about the Rabenstein's reaction between MeHg with low molecular mass thiol (LMM-SH) molecules (cysteine, GSH, acetyl-CoA, lipoate, homocysteine) with abundant high molecular mass thiol (HMM-SH) molecules (albumin, hemoglobin) and HMM-SeH (GPxs, Selenoprotein P, TrxR1-3) are needed. The study of MeHg migration from -S(e)-Hg- bonds to free -S(e)H groups (Rabenstein's Reaction) in pure chemical systems and neural cells (with special emphasis to the LMM-SH and HMM-S(e)H molecules cited above) will be critical to developing realistic constants to be used in silico models that will predict the distribution of MeHg in humans.
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Affiliation(s)
- Pablo A Nogara
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Cláudia S Oliveira
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Gabriela L Schmitz
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Paulo C Piquini
- Departamento de Física, CCNE, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
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Liu J, Jiang T, Wang F, Zhang J, Wang D, Huang R, Yin D, Liu Z, Wang J. Inorganic sulfur and mercury speciation in the water level fluctuation zone of the Three Gorges Reservoir, China: The role of inorganic reduced sulfur on mercury methylation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:1112-1123. [PMID: 29153472 DOI: 10.1016/j.envpol.2017.11.045] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/06/2017] [Accepted: 11/11/2017] [Indexed: 06/07/2023]
Abstract
The water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China is a unique geomorphological unit that undergoes annual flooding and drying alternation cycle. The alternating redox conditions within the WLFZ are expected to result in dynamic cycling of reduced sulfur species, which could affect mercury (Hg) methylation due to the high affinity of reduced sulfur species to both inorganic divalent mercury (Hg(II)i) and methylmercury (MeHg). Variations of inorganic sulfur species (measured as acid volatile sulfide, chromium reductive sulfur, elemental sulfur, and water-soluble sulfate), total mercury (THg) and MeHg were studied at two typical WLFZ sites in the TGR from July 2015 to June 2016. Whereas the water-soluble sulfate contents stayed essentially constant, the reduced inorganic sulfur contents varied greatly as the water level changed. Compared with the control soils, the MeHg contents in the WLFZ soils increased, suggesting that water level fluctuations accelerated the methylation process of Hg(II)i. In situ Hg(II)i-methylation also appeared to occur in the sub-layer of the drained sediment during the draw-down season. The significant correlation between MeHg and elemental sulfur (S(0)) further suggests that polysulfides may have played a role in Hg(II)i-methylation by increasing the bioavailable Hg(II)i content in the WLFZ of the TGR.
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Affiliation(s)
- Jiang Liu
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China; Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg MB R3T 2N2, Canada
| | - Tao Jiang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden
| | - Feiyue Wang
- Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg MB R3T 2N2, Canada.
| | - Jinzhong Zhang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China.
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Rong Huang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Deliang Yin
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Zeyan Liu
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
| | - Jinzhu Wang
- College of Resources and Environment, Southwest University, Key Laboratory of Eco-environments in the Three Gorges Reservoir Region, Ministry of Education, Chongqing 400715, PR China
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Xiang Y, Wang Y, Zhang C, Shen H, Wang D. Water level fluctuations influence microbial communities and mercury methylation in soils in the Three Gorges Reservoir, China. J Environ Sci (China) 2018; 68:206-217. [PMID: 29908740 DOI: 10.1016/j.jes.2018.03.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/03/2018] [Accepted: 03/09/2018] [Indexed: 06/08/2023]
Abstract
Reservoirs tend to have enhanced methylmercury (MeHg) concentrations compared to natural lakes and rivers, and water level fluctuations can promote MeHg production. Until now, little research has been conducted on the effects of microorganisms in soils for the formation of MeHg during different drying and flooding alternating conditions in the Three Gorges Reservoir (TGR). This study aimed to understand how water level fluctuations affect soil microbial composition and mercury concentrations, and if such microbial variations are related to Hg methylation. The results showed that MeHg concentrations and the ratios of MeHg to THg (MeHg%) in soils were higher in the seasonally drying and flooding alternating areas (DFAs, 175-155m) than those in the non-inundated (NIAs, >175m) and inundated areas (IAs, <145m). However, MeHg% in all samples was less than 1%, indicating that the Hg methylation activity in the soils of the TGR was under a low level. 454 high-throughput sequencing of 16S rRNA gene amplicons showed that soil bacterial abundance and diversity were relatively higher in DFA compared to those in NIA and IA, and microbial community composition varied in these three areas. At the family level, those groups in Deltaproteobacteria and Methanomicrobia that might have many Hg methylators were also showed a higher relative abundance in DFA, which might be the reason for the higher MeHg production in these areas. Overall, our results suggested that seasonally water level fluctuations can enhance the microbial abundance and diversity, as well as MeHg production in the TGR.
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Affiliation(s)
- Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Engineering Research Center for Agricultural Non-point Source Pollution Control in the Three Gorges Reservoir Area, Chongqing 400715, China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400715, China
| | - Cheng Zhang
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Engineering Research Center for Agricultural Non-point Source Pollution Control in the Three Gorges Reservoir Area, Chongqing 400715, China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400715, China
| | - Hong Shen
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Engineering Research Center for Agricultural Non-point Source Pollution Control in the Three Gorges Reservoir Area, Chongqing 400715, China.
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Engineering Research Center for Agricultural Non-point Source Pollution Control in the Three Gorges Reservoir Area, Chongqing 400715, China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400715, China.
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Hoy KS, Feng W, Chris Le X. Microbial methylation of mercury in the water-level fluctuation zone of the Three Gorges Reservoir, China. J Environ Sci (China) 2018; 68:218-220. [PMID: 29908741 DOI: 10.1016/j.jes.2018.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Karen S Hoy
- Department of Chemistry and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada
| | - Wei Feng
- Department of Chemistry and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada
| | - X Chris Le
- Department of Chemistry and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada.
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Strickman RJ, Mitchell CPJ. Mercury methylation in stormwater retention ponds at different stages in the management lifecycle. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:595-606. [PMID: 29376168 DOI: 10.1039/c7em00486a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Stormwater retention ponds effectively manage erosion, flooding, and pollutant loadings, but are also sources of methylmercury (MeHg), a bioaccumulative neurotoxin which is produced by anaerobic aquatic microorganisms. Stormwater retention ponds have a 10-15 year working life, after which they are dredged and reflooded. In this study, we related MeHg biogeochemistry to the different stages of the management lifecycle. In a new, a dredged, and a mature stormwater retention pond, we measured MeHg and inorganic mercury (IHg) concentrations, and the potential for MeHg formation (Kmeth), during the early summer, peak summer, and fall of 2013. In our study sites, MeHg concentrations appear to be driven by mercury (Hg) methylation, indicated by significant correlations between Kmeth values and MeHg concentrations and the percent of Hg present as MeHg. Relationships between Hg variables and ancillary biogeochemistry suggest that Hg methylation is carried out by sulfate reducing bacteria, but that the process is modulated by the supply of IHg substrate, sediment total and labile organic carbon, and possibly competition with nitrate reducers. Wetlands at different points in the management lifecycle differ in terms of their MeHg biogeochemistry. The organic matter-poor new wetland had low MeHg production (mean Kmeth 0.014 per day) and sediment concentrations (mean 0.015 ng g-1), while the mature wetland both produced and accumulated MeHg about five times more actively. Methylmercury production capacity was only temporarily reduced in the reflooded sediments of the dredged wetland, which experienced rapid increases in Kmeth values from low (mean 0.015 per day) immediately after dredging, to values similar to those in the mature wetland after five months. This pattern may have been related to recolonization of the sediments with mercury methylators or increased microbial activities in response to the addition of fresh organic matter. Additional studies should focus on the applicability of these patterns to stormwater retention ponds in other areas, and particularly investigate the effects of stormwater pond dredging on their microbial ecology and MeHg biogeochemistry.
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Affiliation(s)
- R J Strickman
- University of Toronto Scarborough, Department of Physical and Environmental Sciences, 1285 Military Trail, Toronto, Ontario M4C 1A4, Canada.
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Yin D, Wang Y, Jiang T, Qin C, Xiang Y, Chen Q, Xue J, Wang D. Methylmercury production in soil in the water-level-fluctuating zone of the Three Gorges Reservoir, China: The key role of low-molecular-weight organic acids. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 235:186-196. [PMID: 29289829 DOI: 10.1016/j.envpol.2017.12.072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/01/2017] [Accepted: 12/20/2017] [Indexed: 06/07/2023]
Abstract
As important parts of dissolved organic matter, low-molecular-weight organic acids (LMWOAs) typically play important roles in desorbing Hg(II) from the soil solid-phase, which may directly or indirectly impact methylmercury (MeHg) production. However, the mechanism of these processes remains unclear. To better understand the effects of LMWOAs on Hg methylation in the soil, a field study was conducted to investigate the distribution of LMWOAs and their relationship with soil MeHg in a seasonally inundated area in the Three Gorges Reservoir (TGR), China. Meanwhile, laboratory simulation experiments were performed to determine the potential mechanism of LMWOAs in Hg methylation. The field investigation detected considerable amounts of LMWOAs in soil, among which tartaric acid and oxalic acid were dominant components. Among which, tartaric acid and oxalic acid were dominant components. Also, a seasonally and spatially heterogeneous distribution of LMWOAs in soil was observed. Notably, a significant positive relationship was found between MeHg concentrations and LMWOA pools in soil (r = 0.969, p < .01), implying that LMWOAs could promote soil MeHg production. The simulation experiments confirmed that the MeHg levels in soil were largely elevated with the addition of LMWOAs, which occurred mainly in oxygen-deficient environment and was mediated by biotic factors. The soluble Hg-LMWOA complexes, which were formed by the enhanced desorption of Hg(II) from solid-phase, were mostly responsible for the elevated MeHg production in soil. Moreover, those LMWOAs with more carboxylic groups were believed to enhance the net production of MeHg. The generated MeHg in sediment could diffuse into the overlying water, which thus poses a potential threat to the aquatic food web. Therefore, the enhanced Hg methylation caused by LMWOAs should be given more attention, especially in a seasonally inundated ecosystem, where the MeHg exposure is usually related to fishery activities.
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Affiliation(s)
- Deliang Yin
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yongmin Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Tao Jiang
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Caiqing Qin
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yuping Xiang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qiuyu Chen
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Jinping Xue
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400715, China.
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Hsu-Kim H, Eckley CS, Achá D, Feng X, Gilmour CC, Jonsson S, Mitchell CPJ. Challenges and opportunities for managing aquatic mercury pollution in altered landscapes. AMBIO 2018; 47:141-169. [PMID: 29388127 PMCID: PMC5794684 DOI: 10.1007/s13280-017-1006-7] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The environmental cycling of mercury (Hg) can be affected by natural and anthropogenic perturbations. Of particular concern is how these disruptions increase mobilization of Hg from sites and alter the formation of monomethylmercury (MeHg), a bioaccumulative form of Hg for humans and wildlife. The scientific community has made significant advances in recent years in understanding the processes contributing to the risk of MeHg in the environment. The objective of this paper is to synthesize the scientific understanding of how Hg cycling in the aquatic environment is influenced by landscape perturbations at the local scale, perturbations that include watershed loadings, deforestation, reservoir and wetland creation, rice production, urbanization, mining and industrial point source pollution, and remediation. We focus on the major challenges associated with each type of alteration, as well as management opportunities that could lessen both MeHg levels in biota and exposure to humans. For example, our understanding of approximate response times to changes in Hg inputs from various sources or landscape alterations could lead to policies that prioritize the avoidance of certain activities in the most vulnerable systems and sequestration of Hg in deep soil and sediment pools. The remediation of Hg pollution from historical mining and other industries is shifting towards in situ technologies that could be less disruptive and less costly than conventional approaches. Contemporary artisanal gold mining has well-documented impacts with respect to Hg; however, significant social and political challenges remain in implementing effective policies to minimize Hg use. Much remains to be learned as we strive towards the meaningful application of our understanding for stakeholders, including communities living near Hg-polluted sites, environmental policy makers, and scientists and engineers tasked with developing watershed management solutions. Site-specific assessments of MeHg exposure risk will require new methods to predict the impacts of anthropogenic perturbations and an understanding of the complexity of Hg cycling at the local scale.
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Affiliation(s)
- Heileen Hsu-Kim
- Department of Civil & Environmental Engineering, Duke University, 121 Hudson Hall, Box 90287, Durham, NC 27708 USA
| | - Chris S. Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101 USA
| | - Dario Achá
- Unidad de Calidad Ambiental, Instituto de Ecología, Carrera de Biología, Universidad Mayor de San Andrés, P.O. Box 10077, La Paz, Bolivia
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 China
| | - Cynthia C. Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd, Edgewater, MD 21037-0028 USA
| | - Sofi Jonsson
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Svante Arrhenius väg 8, 11418 Stockholm, Sweden
| | - Carl P. J. Mitchell
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4 Canada
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