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Li R, Yan J, Wang C, Yang S, Zhang L, Peng T, Zhu W, Li P, Zhang L, Feng X. Mercury sources, transport, and transformation in rainfall-runoff processes: Mercury isotope approach. WATER RESEARCH 2024; 261:122044. [PMID: 38972237 DOI: 10.1016/j.watres.2024.122044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 06/25/2024] [Accepted: 07/02/2024] [Indexed: 07/09/2024]
Abstract
Mercury (Hg) in runoff water poses significant ecological risks to aquatic ecosystems that can affect organisms. However, accurately identifying the sources and transformation processes of Hg in runoff water is challenging due to complex natural conditions. This study provides a comprehensive investigation of Hg dynamics in water from rainfall to runoff. The Hg isotope fractionation in water was characterized, which allows accurate quantification of Hg sources, transport, and transformations in rainfall-runoff processes. Δ200Hg and corrected Δ199Hg values can serve as reliable tracers for identifying Hg sources in the runoff water and the variation of δ202Hg can be explained by Hg transformation processes. During runoff migration processes, Hg from rainfall is rapidly absorbed on the land surface, while terrestrial Hg entering the water by the dissolution process becomes the primary component of dissolved mercury (DHg). Besides the dissolution and adsorption, microbial Hg(II) reduction and demethylation of MeHg were dominant processes for DHg in the runoff water that flows through the rice paddies, while photochemical Hg(II) reduction was the dominant process for DHg in the runoff water with low water exchange rates. Particulate Hg (PHg) in runoff water is dominantly originated by the terrestrial material and derived from the dissolution and adsorption process. Tracking sources and transformations of Hg in runoff water during the rainfall-runoff process provides a basis for studying Hg pollution in larger water bodies under complex environmental factors.
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Affiliation(s)
- Ruolan Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junyao Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chuan Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaochen Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Lin Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, Puding 562100, China
| | - Tao Peng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, Puding 562100, China
| | - Wei Zhu
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto M3H5T4, Canada
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Zhang K, Pu Q, Liu J, Hao Z, Zhang L, Zhang L, Fu X, Meng B, Feng X. Using Mercury Stable Isotopes to Quantify Directional Soil-Atmosphere Hg(0) Exchanges in Rice Paddy Ecosystems: Implications for Hg(0) Emissions to the Atmosphere from Land Surfaces. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11053-11062. [PMID: 38867369 DOI: 10.1021/acs.est.4c02143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Gaseous elemental mercury [Hg(0)] emissions from soils constitute a large fraction of global total Hg(0) emissions. Existing studies do not distinguish biotic- and abiotic-mediated emissions and focus only on photoreduction mediated emissions, resulting in an underestimation of soil Hg(0) emissions into the atmosphere. In this study, directional mercury (Hg) reduction pathways in paddy soils were identified using Hg isotopes. Results showed significantly different isotopic compositions of Hg(0) between those produced from photoreduction (δ202Hg = -0.80 ± 0.67‰, Δ199Hg = -0.38 ± 0.18‰), microbial reduction (δ202Hg = -2.18 ± 0.25‰, Δ199Hg = 0.29 ± 0.38‰), and abiotic dark reduction (δ202Hg = -2.31 ± 0.25‰, Δ199Hg = 0.50 ± 0.22‰). Hg(0) exchange fluxes between the atmosphere and the paddy soils were dominated by emissions, with the average flux ranging from 2.2 ± 5.7 to 16.8 ± 21.7 ng m-2 h-1 during different sampling periods. Using an isotopic signature-based ternary mixing model, we revealed that photoreduction is the most important contributor to Hg(0) emissions from paddy soils. Albeit lower, microbial and abiotic dark reduction contributed up to 36 ± 22 and 25 ± 15%, respectively, to Hg(0) emissions on the 110th day. These novel findings can help improve future estimation of soil Hg(0) emissions from rice paddy ecosystems, which involve complex biotic-, abiotic-, and photoreduction processes.
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Affiliation(s)
- Kun Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiang Pu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jiang Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhengdong Hao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lijuan Zhang
- Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario M3H 5T4, Canada
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Vaňková M, Domingues Vieira AM, Ettler V, Vaněk A, Trubač J, Penížek V, Mihaljevič M. Tracing anthropogenic mercury in soils from Fe-Hg mining/smelting area: Isotopic and speciation insights. CHEMOSPHERE 2024; 357:142038. [PMID: 38621486 DOI: 10.1016/j.chemosphere.2024.142038] [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: 12/08/2023] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/17/2024]
Abstract
Mercury (Hg) stable isotope ratios supplemented by Hg solid speciation data were determined in soils in a former Fe-Hg mining/smelting area (Jedová hora, Czech Republic, Central Europe). The dominant Hg phase in the studied soils was found to be cinnabar (HgS). A secondary form of soil Hg(II) was represented by Hg weakly and strongly bound to mineral (micro)particles, as revealed by thermo-desorption analysis. These Hg species probably play a key role in local soil Hg processes and biogeochemical cycling. The Hg isotopic data generally showed small differences between HgS (-1.1 to -0.8‰; δ202Hg) and the soil samples (-1.4 to -0.9‰; δ202Hg), as well as limited isotopic variability within the two studied soil profiles. On the other hand, the detected negative δ202Hg shift (∼0.4‰) in organic horizons compared to mineral soils in the highly contaminated profile suggests the presence of secondary post-depositional Hg processes, such as sorption or redox changes. For the less contaminated profile, the observed Hg isotopic variation (∼0.3‰; δ202Hg) in the subsurface mineral soil compared to both overlying and underlying horizons is likely due to cyclic redox reactions associated with Hg isotopic fractionation. We assume that the adsorption of Hg(II) to secondary Fe(III)/Mn(III,IV)-oxides could be of major importance in such cases.
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Affiliation(s)
- Maria Vaňková
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00 Praha 2, Czech Republic.
| | - Alda Maria Domingues Vieira
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00 Praha 2, Czech Republic.
| | - Vojtěch Ettler
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00 Praha 2, Czech Republic.
| | - Aleš Vaněk
- Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha 6, Czech Republic.
| | - Jakub Trubač
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00 Praha 2, Czech Republic.
| | - Vít Penížek
- Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha 6, Czech Republic.
| | - Martin Mihaljevič
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00 Praha 2, Czech Republic.
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Zhu W, Li Z, Li P, Sommar J, Fu X, Feng X, Yu B, Zhang W, Reis AT, Pereira E. Legacy Mercury Re-emission and Subsurface Migration at Contaminated Sites Constrained by Hg Isotopes and Chemical Speciation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:5336-5346. [PMID: 38472090 DOI: 10.1021/acs.est.3c07276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
The re-emission and subsurface migration of legacy mercury (Hg) are not well understood due to limited knowledge of the driving processes. To investigate these processes at a decommissioned chlor-alkali plant, we used mercury stable isotopes and chemical speciation analysis. The isotopic composition of volatilized Hg(0) was lighter compared to the bulk total Hg (THg) pool in salt-sludge and adjacent surface soil with mean ε202HgHg(0)-THg values of -3.29 and -2.35‰, respectively. Hg(0) exhibited dichotomous directions (E199HgHg(0)-THg = 0.17 and -0.16‰) of mass-independent fractionation (MIF) depending on the substrate from which it was emitted. We suggest that the positive MIF enrichment during Hg(0) re-emission from salt-sludge was overall controlled by the photoreduction of Hg(II) primarily ligated by Cl- and/or the evaporation of liquid Hg(0). In contrast, O-bonded Hg(II) species were more important in the adjacent surface soils. The migration of Hg from salt-sludge to subsurface soil associated with selective Hg(II) partitioning and speciation transformation resulted in deep soils depleted in heavy isotopes (δ202Hg = -2.5‰) and slightly enriched in odd isotopes (Δ199Hg = 0.1‰). When tracing sources using Hg isotopes, it is important to exercise caution, particularly when dealing with mobilized Hg, as this fraction represents only a small portion of the sources.
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Affiliation(s)
- Wei Zhu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå SE-90183, Sweden
| | - Zhonggen Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- School of Resources and Environment, Zunyi Normal College, Zunyi 563006, China
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ben Yu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Ana T Reis
- EPIUnit─Instituto de Saúde Pública, Universidade do Porto, Porto 4050-600, Portugal
- Laboratório para a Investigação Integrativa e Translacional em Saúde Populacional (ITR), Porto 4050-600, Portugal
| | - Eduarda Pereira
- LAQV-REQUIMTE─Associated Laboratory for Green Chemistry, University of Aveiro, Aveiro 3810-193, Portugal
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5
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Yang YH, Kim MS, Park J, Kwon SY. Atmospheric mercury uptake and accumulation in forests dependent on climatic factors. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:519-529. [PMID: 38344926 DOI: 10.1039/d3em00454f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The environmental and climatic factors dictating atmospheric mercury (Hg) uptake by foliage and accumulation within the forest floor are evaluated across six mountain sites, South Korea, using Hg concentration and Hg stable isotope analyses. The isotope ratios of total gaseous Hg (TGM) at six mountains are explained by local anthropogenic Hg emission influence and partly by mountain elevation and wind speed. The extent to which TGM is taken up by foliage is not dependent on the site-specific TGM concentration, but by the local wind speed, which facilitates TGM passage through dense deciduous canopies in the Korean forests. This is depicted by the significant positive relationship between wind speed and foliage Hg concentration (r2 = 0.92, p < 0.05) and the magnitude of δ202Hg shift from TGM to foliage (r2 = 0.37, p > 0.05), associated with TGM uptake and oxidation by foliar tissues. The litter and topsoil Hg concentrations and isotope ratios reveal relationships with a wide range of factors, revealing lower Hg level and greater isotopic fractionation at sites with low elevation, high wind speed, and high mean warmest temperature. We attribute this phenomenon to active TGM re-emission from the forest floor at sites with high wind speed and high temperature, caused by turnover of labile organic matter and decomposition. In contrast to prior studies, we observe no significant effect of precipitation on forest Hg accumulation but precipitation appears to reduce foliage-level Hg uptake by scavenging atmospheric Hg species available for stomata uptake. The results of this study would enable better prediction of future atmospheric and forest Hg influence under climate change.
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Affiliation(s)
- Yo Han Yang
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea.
| | - Min-Seob Kim
- Environmental Measurement & Analysis Center, National Institute of Environmental Research, 42 Hwangyong-Ro, Seo-Gu, Incheon 22689, South Korea
| | - Jaeseon Park
- Environmental Measurement & Analysis Center, National Institute of Environmental Research, 42 Hwangyong-Ro, Seo-Gu, Incheon 22689, South Korea
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea.
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6
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Liu H, Zheng W, Gao Y, Yang L, Yue F, Huang T, Xie Z. Increased Contribution of Circumpolar Deep Water Upwelling to Methylmercury in the Upper Ocean around Antarctica: Evidence from Mercury Isotopes in the Ornithogenic Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:2762-2773. [PMID: 38294849 DOI: 10.1021/acs.est.3c06923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Upwelling plays a pivotal role in supplying methylmercury (MeHg) to the upper oceans, contributing to the bioaccumulation of MeHg in the marine food web. However, the influence of the upwelling of Circumpolar Deep Water (CDW), the most voluminous water mass in the Southern Ocean, on the MeHg cycle in the surrounding oceans and marine biota of Antarctica remains unclear. Here, we study the mercury (Hg) isotopes in an ornithogenic sedimentary profile strongly influenced by penguin activity on Ross Island, Antarctica. Results indicate that penguin guano is the primary source of Hg in the sediments, and the mass-independent isotope fractionation of Hg (represented by Δ199Hg) can provide insights on the source of marine MeHg accumulated by penguin. The Δ199Hg in the sediments shows a significant decrease at ∼1550 CE, which is primarily attributed to the enhanced upwelling of CDW that brought more MeHg with lower Δ199Hg from the deeper seawater to the upper ocean. We estimate that the contribution of MeHg from the deeper seawater may reach more than 38% in order to explain the decline in Δ199Hg at ∼1550 CE. Moreover, we found that the intensified upwelling may have increased the MeHg exposure for marine organisms, highlighting the importance of CDW upwelling on the MeHg cycle in Antarctic coastal ecosystems.
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Affiliation(s)
- Hongwei Liu
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wang Zheng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287, United States
| | - Yuesong Gao
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Lianjiao Yang
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fange Yue
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tao Huang
- School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui 230601, China
| | - Zhouqing Xie
- Department of Environmental Science and Engineering, Anhui Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei, Anhui 230026, China
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Kim YG, Kwon SY, Washburn SJ, Hong Y, Han SH, Lee M, Park JH. Environmental forensics approach to source investigation in a mercury contaminated river: Insights from mercury stable isotopes. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132559. [PMID: 37729710 DOI: 10.1016/j.jhazmat.2023.132559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/10/2023] [Accepted: 09/12/2023] [Indexed: 09/22/2023]
Abstract
Environmental forensics approach was applied to assess the efficacy of mercury (Hg) stable isotopes for source screening and decision-making in the Hyeongsan River, South Korea. Four Hg contamination scenarios were identified- atmospheric Hg emissions from a steel manufacturing industry, upstream riverine Hg transport, and industrial Hg releases and historical landfill collapse from Gumu Creek. The absence of significant Hg isotope difference between the Hyeongsan River sediments (δ202Hg; -0.46 ± 0.17‰, Δ199Hg; -0.04 ± 0.06‰) and the Gumu Creek sediment (δ202Hg; -0.39 ± 0.26‰, Δ199Hg; -0.04 ± 0.03‰) confirm that Hg source is originated from Gumu Creek. The heterogeneous Hg distribution throughout Gumu Creek and statistically similar Hg isotope ratios between Gumu Creek and solid waste cores from the landfill suggests that the landfill collapse is the dominant source to the Hyeongsan-Gumu system. Present Hg releases is also possible given the elevated and matching Δ199Hg between some riverine sediments and wastewater sampled from the landfill. The ternary mixing model estimates that the landfill collapse and wastewater releases contribute 61 ± 25 % and 22 ± 11 %, and the regional background, reflecting terrestrial runoff using deep sediment cores, explain 17 ± 24 % of Hg to the riverine sediment. We suggest that Hg isotopes can be used for routine source screening in areas where Hg sources are unknown.
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Affiliation(s)
- Young Gwang Kim
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea; Institute for Convergence Research and Education in Advanced Technology, Yonsei University, 85 Songdogwahak-Ro, Yeonsu-Gu, Incheon 21983, South Korea.
| | - Spencer J Washburn
- Geosyntec Consultants, Inc., 100 Washington Ave. S, Suite 1590, Minneapolis, MN 55401, USA
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-Ro, Sejong City 30019, South Korea
| | - Seung Hee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-Ro, Buk-Gu, Gwangju 61005, South Korea
| | - Mikyung Lee
- Water Environmental Engineering Research Division, National Institute of Environmental Research, 42 Hwangyeong-Ro, Seo-Gu, Incheon 22689, South Korea
| | - Ji Hyoung Park
- Water Environmental Engineering Research Division, National Institute of Environmental Research, 42 Hwangyeong-Ro, Seo-Gu, Incheon 22689, South Korea
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8
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Li C, Jiskra M, Nilsson MB, Osterwalder S, Zhu W, Mauquoy D, Skyllberg U, Enrico M, Peng H, Song Y, Björn E, Bishop K. Mercury deposition and redox transformation processes in peatland constrained by mercury stable isotopes. Nat Commun 2023; 14:7389. [PMID: 37968321 PMCID: PMC10652010 DOI: 10.1038/s41467-023-43164-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 11/02/2023] [Indexed: 11/17/2023] Open
Abstract
Peatland vegetation takes up mercury (Hg) from the atmosphere, typically contributing to net production and export of neurotoxic methyl-Hg to downstream ecosystems. Chemical reduction processes can slow down methyl-Hg production by releasing Hg from peat back to the atmosphere. The extent of these processes remains, however, unclear. Here we present results from a comprehensive study covering concentrations and isotopic signatures of Hg in an open boreal peatland system to identify post-depositional Hg redox transformation processes. Isotope mass balances suggest photoreduction of HgII is the predominant process by which 30% of annually deposited Hg is emitted back to the atmosphere. Isotopic analyses indicate that above the water table, dark abiotic oxidation decreases peat soil gaseous Hg0 concentrations. Below the water table, supersaturation of gaseous Hg is likely created more by direct photoreduction of rainfall rather than by reduction and release of Hg from the peat soil. Identification and quantification of these light-driven and dark redox processes advance our understanding of the fate of Hg in peatlands, including the potential for mobilization and methylation of HgII.
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Affiliation(s)
- Chuxian Li
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
| | - Martin Jiskra
- Environmental Geosciences, University of Basel, Basel, Switzerland
| | - Mats B Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Wei Zhu
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Dmitri Mauquoy
- School Geosciences, University of Aberdeen, Scotland, UK
| | - Ulf Skyllberg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Maxime Enrico
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, TotalEnergies, LFCR, IPREM, Pau, France
| | - Haijun Peng
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Yu Song
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Erik Björn
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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9
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Du H, Wang X, Yuan W, Wu F, Jia L, Liu N, Lin CJ, Gan J, Zeng F, Wang K, Feng X. Elevated Mercury Deposition, Accumulation, and Migration in a Karst Forest. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17490-17500. [PMID: 37908057 DOI: 10.1021/acs.est.3c05409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The karst forest is one of the extremely sensitive and fragile ecosystems in southwest China, where the biogeochemical cycling of mercury (Hg) is largely unknown. In this study, we investigated the litterfall deposition, accumulation, and soil migration of Hg in an evergreen-deciduous broadleaf karst forest using high-resolution sampling and stable isotope techniques. Results show that elevated litterfall Hg concentrations and fluxes in spring are due to the longer lifespan of evergreen tree foliage exposed to atmospheric Hg0. The hillslope has 1-2 times higher litterfall Hg concentration compared to the low-lying land due to the elevated atmospheric Hg levels induced by topographical and physiological factors. The Hg isotopic model suggests that litterfall Hg depositions account for ∼80% of the Hg source contribution in surface soil. The spatial trend of litterfall Hg deposition cannot solely explain the trend of Hg accumulation in the surface soil. Indeed, soil erosion enhances Hg accumulation in soil of low-lying land, with soil Hg concentration up to 5-times greater than the concentration on the hillslope. The high level of soil Hg migration in the karst forest poses significant ecological risks to groundwater and downstream aquatic ecosystems.
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Affiliation(s)
- Hu Du
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Longyu Jia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Nantao Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Jiang Gan
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Fuping Zeng
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Kelin Wang
- Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China
- Huanjiang Observation and Research Station for Karst Ecosystems, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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10
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Wu F, Yang L, Wang X, Yuan W, Lin CJ, Feng X. Mercury Accumulation and Sequestration in a Deglaciated Forest Chronosequence: Insights from Particulate and Mineral-Associated Forms of Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16512-16521. [PMID: 37857302 DOI: 10.1021/acs.est.3c03107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Understanding mercury (Hg) complexation with soil organic matter is important in assessing atmospheric Hg accumulation and sequestration processes in forest ecosystems. Separating soil organic matter into particulate organic matter (POM) and mineral-associated organic matter (MAOM) can help in the understanding of Hg dynamics and cycling due to their very different chemical constituents and associated formation and functioning mechanisms. The concentration of Hg, carbon, and nitrogen contents and isotopic signatures of POM and MAOM in a deglaciated forest chronosequence were determined to construct the processes of Hg accumulation and sequestration. The results show that Hg in POM and MAOM are mainly derived from atmospheric Hg0 deposition. Hg concentration in MAOM is up to 76% higher than that in POM of broadleaf forests and up to 60% higher than that in POM of coniferous forests. Hg accumulation and sequestration in organic soil vary with the vegetation succession. Variations of δ202Hg and Δ199Hg are controlled by source mixing in the broadleaf forest and by Hg sequestration processes in the coniferous forest. Accumulation of atmospheric Hg and subsequent microbial reduction enrich heavier Hg isotopes in MAOM compared to POM due to the specific chemical constituents and nutritional role of MAOM.
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Affiliation(s)
- Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Luhan Yang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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11
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Chen C, Huang JH, Li K, Osterwalder S, Yang C, Waldner P, Zhang H, Fu X, Feng X. Isotopic Characterization of Mercury Atmosphere-Foliage and Atmosphere-Soil Exchange in a Swiss Subalpine Coniferous Forest. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15892-15903. [PMID: 37788478 DOI: 10.1021/acs.est.3c03576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
To understand the role of vegetation and soil in regulating atmospheric Hg0, exchange fluxes and isotope signatures of Hg were characterized using a dynamic flux bag/chamber at the atmosphere-foliage/soil interfaces at the Davos-Seehornwald forest, Switzerland. The foliage was a net Hg0 sink and took up preferentially the light Hg isotopes, consequently resulting in large shifts (-3.27‰) in δ202Hg values. The soil served mostly as net sources of atmospheric Hg0 with higher Hg0 emission from the moss-covered soils than from bare soils. The negative shift of δ202Hg and Δ199Hg values of the efflux air relative to ambient air and the Δ199Hg/Δ201Hg ratio among ambient air, efflux air, and soil pore gas highlight that Hg0 re-emission was strongly constrained by soil pore gas evasion together with microbial reduction. The isotopic mass balance model indicates 8.4 times higher Hg0 emission caused by pore gas evasion than surface soil photoreduction. Deposition of atmospheric Hg0 to soil was noticeably 3.2 times higher than that to foliage, reflecting the high significance of the soil to influence atmospheric Hg0 isotope signatures. This study improves our understanding of Hg atmosphere-foliage/soil exchange in subalpine coniferous forests, which is indispensable in the model assessment of forest Hg biogeochemical cycling.
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Affiliation(s)
- Chaoyue Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jen-How Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
| | - Kai Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Stefan Osterwalder
- Environmental Geosciences, University of Basel, 4056 Basel, Switzerland
- Institute of Agricultural Sciences, ETH Zurich, 8092 Zurich, Switzerland
| | - Chenmeng Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Peter Waldner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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12
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Schwab L, Gallati N, Reiter SM, Kimber RL, Kumar N, McLagan DS, Biester H, Kraemer SM, Wiederhold JG. Mercury Isotope Fractionation during Dark Abiotic Reduction of Hg(II) by Dissolved, Surface-Bound, and Structural Fe(II). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15243-15254. [PMID: 37748105 PMCID: PMC10569049 DOI: 10.1021/acs.est.3c03703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/27/2023]
Abstract
Stable mercury (Hg) isotope ratios are an emerging tracer for biogeochemical transformations in environmental systems, but their application requires knowledge of isotopic enrichment factors for individual processes. We investigated Hg isotope fractionation during dark, abiotic reduction of Hg(II) by dissolved iron(Fe)(II), magnetite, and Fe(II) sorbed to boehmite or goethite by analyzing both the reactants and products of laboratory experiments. For homogeneous reduction of Hg(II) by dissolved Fe(II) in continuously purged reactors, the results followed a Rayleigh distillation model with enrichment factors of -2.20 ± 0.16‰ (ε202Hg) and 0.21 ± 0.02‰ (E199Hg). In closed system experiments, allowing reequilibration, the initial kinetic fractionation was overprinted by isotope exchange and followed a linear equilibrium model with -2.44 ± 0.17‰ (ε202Hg) and 0.34 ± 0.02‰ (E199Hg). Heterogeneous Hg(II) reduction by magnetite caused a smaller isotopic fractionation (-1.38 ± 0.07 and 0.13 ± 0.01‰), whereas the extent of isotopic fractionation of the sorbed Fe(II) experiments was similar to the kinetic homogeneous case. Small mass-independent fractionation of even-mass Hg isotopes with 0.02 ± 0.003‰ (E200Hg) and ≈ -0.02 ± 0.01‰ (E204Hg) was consistent with theoretical predictions for the nuclear volume effect. This study contributes significantly to the database of Hg isotope enrichment factors for specific processes. Our findings show that Hg(II) reduction by dissolved Fe(II) in open systems results in a kinetic MDF with a larger ε compared to other abiotic reduction pathways, and combining MDF with the observed MIF allows the distinction from photochemical or microbial Hg(II) reduction pathways.
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Affiliation(s)
- Lorenz Schwab
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
- Doctoral
School in Microbiology and Environmental Science, University of Vienna, 1030 Vienna, Austria
- Environmental
Engineering Institute IIE-ENAC, Soil Biogeochemistry Laboratory, École Polytechnique Fédérale
de Lausanne (EPFL), Route
des Ronquos 86, 1951 Sion, Switzerland
| | - Niklas Gallati
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
| | - Sofie M. Reiter
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
| | - Richard L. Kimber
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
| | - Naresh Kumar
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
- Soil
Chemistry and Chemical Soil Quality Group, Department of Environmental
Sciences, University of Wageningen, Droevendaalsesteeg 3a, 6708 Wageningen, Netherlands
| | - David S. McLagan
- Environmental
Geochemistry Group, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, 38106 Braunschweig, Germany
- Department
of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada
- School
of Environmental Studies, Queen’s
University, Kingston, Ontario K7L 3N6, Canada
| | - Harald Biester
- Environmental
Geochemistry Group, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, 38106 Braunschweig, Germany
| | - Stephan M. Kraemer
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
| | - Jan G. Wiederhold
- Department
of Environmental Geosciences, Centre for Microbiology and Environmental
Systems Science, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
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13
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Mao L, Ren W, Liu X, He M, Lin C, Zhong Y, Tang Y, Ouyang W. Tracking the multiple Hg sources in sediments in a typical river-lake basin by isotope compositions and mixing models. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132166. [PMID: 37531762 DOI: 10.1016/j.jhazmat.2023.132166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/04/2023]
Abstract
In this study, total mercury (THg) contents and Hg isotope compositions in sediments were investigated in the Lianxi River, Zijiang River and South Dongting Lake to identify and quantify multiple Hg sources and evaluate the Hg environmental processes. The THg contents, δ202Hg and Δ199Hg values in sediments were 48.22 ∼ 4284.32 µg/kg, - 1.33 ∼ 0.04‰ and - 0.25 ∼ 0.03‰, respectively. Relatively distinct Hg isotope characteristics of sediments were presented in the Lianxi River, Zijiang River and South Dongting Lake, indicating the dominant Hg sources considerably varied in these regions. Source apportionment based on MixSIAR proved that Hg in sediments mainly originated from industrial activities, and the ternary mixing model concluded non-ferrous metal smelting was the dominant industrial Hg contributor in the Lianxi River. Compared with the Lianxi River, the relative contribution of Hg in sediments from industrial activities significantly decreased, while the relative contributions of Hg from background releases significantly increased in the Zijiang River and South Dongting Lake. Nonetheless, the contribution of industrial Hg in this study area deserves more attention. These results are conducive to further manage Hg pollution.
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Affiliation(s)
- Lulu Mao
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Wenbo Ren
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xitao Liu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Mengchang He
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Chunye Lin
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Ying Zhong
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081 Guiyang, China
| | - Yang Tang
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550081 Guiyang, China
| | - Wei Ouyang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, China
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14
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Shen Z, Liu G, Guo Y, Jiang T, Liu Y, Shi J, Hu L, Yin Y, Cai Y, Jiang G. Dissolved organic matter mediated dark- and photo-aging processes of Hg(II): Critical impacts of binding sites and sulfidation on Hg(II) abiotic reduction and microbial methylation. WATER RESEARCH 2023; 242:120294. [PMID: 37429137 DOI: 10.1016/j.watres.2023.120294] [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: 02/19/2023] [Revised: 06/25/2023] [Accepted: 06/29/2023] [Indexed: 07/12/2023]
Abstract
Dissolved organic matter (DOM)-mediated divalent mercury (Hg(II)) aging kinetics play a crucial role in controlling Hg(II) transformation and bioavailability in natural aquatic environments. However, the differential environmental behaviors of new and aged Hg(II) in a same reaction system remains unknown. In this study, multi-isotope tracing was used to investigate the impacts of binding site and sulfidation during DOM-mediated Hg(II) aging processes on Hg(II) reduction and microbial methylation in the same reaction system. Stepwise reduction approach and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) demonstrate that DOM-mediated dark aging processes are mainly driven by the rearrangement of DOM binding sites with Hg(II), but not the formation of mercury sulfide nanoparticles (HgSNP). The abundant but weaker RO/N (carboxyl and amino) Hg(II)-binding sites are replaced with stronger RSH (thiol) moieties towards Hg(II) binding with aging, resulting in a decrease in Hg(II) reduction. In contrast, besides reduction, DOM-mediated Hg(II) photoaging induces the formation of HgSNP, as revealed by LC-ICP-MS, which in turn decreases the microbial methylation potential of Hg(II). These findings help better understand and predict the kinetic characteristics of Hg(II) reactivity and its influence on Hg cycle within natural aquatic environments.
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Affiliation(s)
- Zelin Shen
- 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; University of Chinese Academy of Sciences (UCAS), Beijing 100049, China
| | - Guangliang Liu
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yingying Guo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Yanwei Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jianbo Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ligang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yongguang Yin
- 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; University of Chinese Academy of Sciences (UCAS), Beijing 100049, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China.
| | - Yong Cai
- 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; Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Guibin Jiang
- 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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15
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Yuan W, Wang X, Lin CJ, Song Q, Zhang H, Wu F, Liu N, Lu H, Feng X. Deposition and Re-Emission of Atmospheric Elemental Mercury over the Tropical Forest Floor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:10686-10695. [PMID: 37437160 DOI: 10.1021/acs.est.3c01222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Significant knowledge gaps exist regarding the emission of elemental mercury (Hg0) from the tropical forest floor, which limit our understanding of the Hg mass budget in forest ecosystems. In this study, biogeochemical processes of Hg0 deposition to and evasion from soil in a Chinese tropical rainforest were investigated using Hg stable isotopic techniques. Our results showed a mean air-soil flux as deposition of -4.5 ± 2.1 ng m-2 h-1 in the dry season and as emission of +7.4 ± 1.2 ng m-2 h-1 in the rainy season. Hg re-emission, i.e., soil legacy Hg evasion, induces negative transitions of Δ199Hg and δ202Hg in the evaded Hg0 vapor, while direct atmospheric Hg0 deposition does not exhibit isotopic fractionation. Using an isotopic mass balance model, direct atmospheric Hg0 deposition to soil was estimated to be 48.6 ± 13.0 μg m-2 year-1. Soil Hg0 re-emission was estimated to be 69.5 ± 10.6 μg m-2 year-1, of which 63.0 ± 9.3 μg m-2 year-1 is from surface soil evasion and 6.5 ± 5.0 μg m-2 year-1 from soil pore gas diffusion. Combined with litterfall Hg deposition (∼34 μg m-2 year-1), we estimated a ∼12.6 μg m-2 year-1 net Hg0 sink in the tropical forest. The fast nutrient cycles in the tropical rainforests lead to a strong Hg0 re-emission and therefore a relatively weaker atmospheric Hg0 sink.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Qinghai Song
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nantao Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Huazheng Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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16
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Zhang H, Fu X, Wu X, Deng Q, Tang K, Zhang L, Sommar J, Sun G, Feng X. Using Mercury Stable Isotopes to Quantify Bidirectional Water-Atmosphere Hg(0) Exchange Fluxes and Explore Controlling Factors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37378655 DOI: 10.1021/acs.est.3c01273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
In this study, exchange fluxes and Hg isotope fractionation during water-atmosphere Hg(0) exchange were investigated at three lakes in China. Water-atmosphere exchange was overall characterized by net Hg(0) emissions, with lake-specific mean exchange fluxes ranging from 0.9 to 1.8 ng m-2 h-1, which produced negative δ202Hg (mean: -1.61 to -0.03‰) and Δ199Hg (-0.34 to -0.16‰) values. Emission-controlled experiments conducted using Hg-free air over the water surface at Hongfeng lake (HFL) showed negative δ202Hg and Δ199Hg in Hg(0) emitted from water, and similar values were observed between daytime (mean δ202Hg: -0.95‰, Δ199Hg: -0.25‰) and nighttime (δ202Hg: -1.00‰, Δ199Hg: -0.26‰). Results of the Hg isotope suggest that Hg(0) emission from water is mainly controlled by photochemical Hg(0) production in water. Deposition-controlled experiments at HFL showed that heavier Hg(0) isotopes (mean ε202Hg: -0.38‰) preferentially deposited to water, likely indicating an important role of aqueous Hg(0) oxidation played during the deposition process. A Δ200Hg mixing model showed that lake-specific mean emission fluxes from water surfaces were 2.1-4.1 ng m-2 h-1 and deposition fluxes to water surfaces were 1.2-2.3 ng m-2 h-1 at the three lakes. Results from the this study indicate that atmospheric Hg(0) deposition to water surfaces indeed plays an important role in Hg cycling between atmosphere and water bodies.
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Affiliation(s)
- Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xian Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qianwen Deng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaihui Tang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto M3H5T4, Ontario, Canada
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Guangyi Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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17
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Zhou Z, Wang H, Li Y. Mercury stable isotopes in the ocean: Analytical methods, cycling, and application as tracers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162485. [PMID: 36858226 DOI: 10.1016/j.scitotenv.2023.162485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
Mercury (Hg) has seven stable isotopes that can be utilized to trace the sources of Hg and evaluate the importance of transport and transformation processes in the cycling of Hg in the environment. The ocean is an integral part of the Earth and plays an important role in the global mercury cycle. However, there is a lack of a systematic review of Hg stable isotopes in marine environments. This review is divided into four sections: a) advances in Hg stable isotope analysis, b) the isotope ratios of Hg in various marine environmental matrices (seawater, sediment, and organisms), c) processes governing stable Hg isotope ratios in the ocean, and d) application of Hg stable isotopes to understand biotic uptake and migration. Mercury isotopes have provided much useful information on marine Hg cycling that cannot be given by Hg concentrations alone. This includes (i) sources of Hg in coastal or estuarine environments, (ii) transformation pathways and mechanisms of different forms of Hg in marine environments, (iii) trophic levels and feeding guilds of marine fish, and (iv) migration/habitat changes of marine fish. With the improvement of methods for seawater Hg isotope analysis (especially species-specific methods) and the measurement of Hg isotope fractionation during natural biogeochemical processes in the ocean, Hg stable isotopes will advance our understanding of the marine Hg cycle in the future, e.g., mercury exchange at the sea-atmosphere interface and seawater-sediment interface, contributions of different water masses to Hg in the ocean, fractionation mechanisms of Hg and MeHg transformation in seawater.
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Affiliation(s)
- Zhengwen Zhou
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Huiling Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Yanbin Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
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18
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Yuan J, Liu Y, Chen S, Peng X, Li YF, Li S, Zhang R, Zheng W, Chen J, Sun R, Heimbürger-Boavida LE. Mercury Isotopes in Deep-Sea Epibenthic Biota Suggest Limited Hg Transfer from Photosynthetic to Chemosynthetic Food Webs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6550-6562. [PMID: 37042785 DOI: 10.1021/acs.est.3c01276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Deep oceans receive mercury (Hg) from upper oceans, sediment diagenesis, and submarine volcanism; meanwhile, sinking particles shuttle Hg to marine sediments. Recent studies showed that Hg in the trench fauna mostly originated from monomethylmercury (MMHg) of the upper marine photosynthetic food webs. Yet, Hg sources in the deep-sea chemosynthetic food webs are still uncertain. Here, we report Hg concentrations and stable isotopic compositions of indigenous biota living at hydrothermal fields of the Indian Ocean Ridge and a cold seep of the South China Sea along with hydrothermal sulfide deposits. We find that Hg is highly enriched in hydrothermal sulfides, which correlated with varying Hg concentrations in inhabited biota. Both the hydrothermal and cold seep biota have small fractions (<10%) of Hg as MMHg and slightly positive Δ199Hg values. These Δ199Hg values are slightly higher than those in near-field sulfides but are 1 order of magnitude lower than the trench counterparts. We suggest that deep-sea chemosynthetic food webs mainly assimilate Hg from ambient seawater/sediments and hydrothermal fluids formed by percolated seawater through magmatic/mantle rocks. The MMHg transfer from photosynthetic to chemosynthetic food webs is likely limited. The contrasting Hg sources between chemosynthetic and trench food webs highlight Hg isotopes as promising tools to trace the deep-sea Hg biogeochemical cycle.
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Affiliation(s)
- Jingjing Yuan
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Yi Liu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Shun Chen
- Deep Sea Science Division, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, 572000 Sanya, Hainan, China
| | - Xiaotong Peng
- Deep Sea Science Division, Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, 572000 Sanya, Hainan, China
| | - Yu-Feng Li
- CAS-HKU Joint Laboratory of Metallomics on Health and Environment, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Beijing Metallomics Facility, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China
| | - Songjing Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Rui Zhang
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Wang Zheng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Jiubin Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, 300072 Tianjin, China
| | - Lars-Eric Heimbürger-Boavida
- Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, 13288 Marseille, France
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19
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Liu N, Cai X, Jia L, Wang X, Yuan W, Lin CJ, Wang D, Feng X. Quantifying Mercury Distribution and Source Contribution in Surface Soil of Qinghai-Tibetan Plateau Using Mercury Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5903-5912. [PMID: 36976750 DOI: 10.1021/acs.est.2c09610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Long-range transport and atmospheric deposition of gaseous mercury (Hg0) result in significant accumulation of Hg in the Qinghai-Tibetan Plateau (QTP). However, there are significant knowledge gaps in understanding the spatial distribution and source contribution of Hg in the surface soil of the QTP and factors influencing Hg accumulation. In this study, we comprehensively investigated Hg concentrations and isotopic signatures in the QTP to address these knowledge gaps. Results show that the average Hg concentration in the surface soil ranks as follows: forest (53.9 ± 36.9 ng g-1) > meadow (30.7 ± 14.3 ng g-1) > steppe (24.5 ± 16.1 ng g-1) > shrub (21.0 ± 11.6 ng g-1). Hg isotopic mass mixing and structural equation models demonstrate that vegetation-mediated atmospheric Hg0 deposition dominates the Hg source in the surface soil, with an average contribution of 62 ± 12% in forests, followed by 51 ± 10% in shrub, 50 ± 13% in steppe, and 45 ± 11% in meadow. Additionally, geogenic sources contribute 28-37% of surface soil Hg accumulation, and atmospheric Hg2+ inputs contribute 10-18% among the four types of biomes. The Hg pool in 0-10 cm surface soil over the QTP is estimated as 8200 ± 3292 Mg. Global warming, permafrost degradation, and anthropogenic influences have likely perturbed Hg accumulation in the soil of QTP.
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Affiliation(s)
- Nantao Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xinyuan Cai
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Longyu Jia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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20
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Xin Y, Zhang X, Zheng D, Zhang Z, Jiang M. Impacts of spectral characteristics of dissolved organic matter on methylmercury contents in peatlands, Northeast China. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:913-923. [PMID: 35366716 DOI: 10.1007/s10653-022-01257-1] [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: 09/02/2021] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Dissolved organic matter (DOM) plays an important role in promoting or suppressing methylmercury (MeHg) production in wetlands. However, the effects of DOM spectral characteristics on MeHg levels remain poorly understood in boreal peatlands in Northeast China, where is undergoing remarkable climate warming. In the present work, soil samples were collected from 22 peatlands in the Greater Khingan Mountains (GKM) to test the hypothesis that DOM spectral properties control MeHg levels. DOM was characterized by UV-Vis absorption and fluorescence spectroscopy; the three-dimensional fluorescence excitation-emission matrix (EEM) was used to unveil the origin of DOM. The average total mercury (THg) and MeHg contents were 112.76 µg/kg and 12.43 µg/kg across all peatlands, respectively. There was a significantly positive correlation between MeHg and the longitude spanning the range from 120 to 123°E (p < 0.05). Proportions of MeHg to THg (%MeHg), 12.3% on average, were positively correlated with DOM humification degree at p < 0.05 level. Protein-like components of DOM (P-like) were negatively related to %MeHg. DOM had positive effects on THg, and P-like components, HIX and BIX can negatively affect THg as well as MeHg. Our findings demonstrate that the spectral characteristics of DOM in soil are crucial to the content of methyl mercury in the GKM soil.
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Affiliation(s)
- Yuan Xin
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China
- Environmental College, Shenyang University, Shenyang, 110044, China
- Key Laboratory of Regional Environment and Eco-Remediation, Ministry of Education, Shenyang University, Shenyang, 110044, China
| | - Xuehui Zhang
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongmei Zheng
- Environmental College, Shenyang University, Shenyang, 110044, China
- Key Laboratory of Regional Environment and Eco-Remediation, Ministry of Education, Shenyang University, Shenyang, 110044, China
| | - Zhongsheng Zhang
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China.
| | - Ming Jiang
- Institute of Northeast Geography and Agroecology, Chinese Academy of Science, No.4888, Shengbei Street, Kuancheng District, Changchun, 130102, China
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21
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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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22
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Božič D, Živković I, Hudobivnik MJ, Kotnik J, Amouroux D, Štrok M, Horvat M. Fractionation of mercury stable isotopes in lichens. CHEMOSPHERE 2022; 309:136592. [PMID: 36167212 DOI: 10.1016/j.chemosphere.2022.136592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/02/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Bio-monitoring of mercury (Hg) in air using transplanted and in-situ lichens was conducted at three locations in Slovenia: (I) the town of Idrija in the area of the former Hg mine, where Hg contamination is well known; (II) Anhovo, a settlement with a cement production plant, which is a source of Hg contamination, and (III) Pokljuka, a part of a national park. Lichens from Pokljuka were transplanted to different sites and sampled four times-once per season, from January 2020 to February 2021. Lichens were set on tree branches, fences, and under cover, allowing them to be exposed to different environmental conditions (e.g., light and rain). The in-situ lichens were sampled at the beginning and the end of the sampling period. The highest concentrations were in the Idrija area, which was consistent with previous research. Significant mass-dependent fractionation has been observed in transplanted lichens during summer period. The δ202Hg changed from -3.0‰ in winter to -1.0‰ in summer and dropped again to the same value in winter the following year. This trend was observed in all samples, except those from the most polluted Idrija sampling site, which was in the vicinity of the former Hg ore-smelting plant. This was likely due to large amounts of Hg originating from polluted soil close to the former smelting plant with a distinct isotopic fingerprint in this local area. The Δ199Hg in transplanted lichens ranged from -0.5‰ to -0.1‰ and showed no seasonal trends. These findings imply that seasonality, particularly in summer months, may affect the isotopic fractionation of Hg and should be considered in the sampling design and data interpretation. This trend was thus described in lichens for the first time. The mechanism behind such change is not yet fully understood.
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Affiliation(s)
- Dominik Božič
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Street 39, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova Street 39, Ljubljana, Slovenia
| | - Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Street 39, Ljubljana, Slovenia
| | - Marta Jagodic Hudobivnik
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Street 39, Ljubljana, Slovenia
| | - Jože Kotnik
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Street 39, Ljubljana, Slovenia
| | - David Amouroux
- The Institute of Analytical Sciences and Physico-Chemistry for Environment and Materials, 2 Avenue Pierre Angot, Pau Cedex 9, France
| | - Marko Štrok
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Street 39, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova Street 39, Ljubljana, Slovenia
| | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Street 39, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova Street 39, Ljubljana, Slovenia.
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23
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Yuan W, Wang X, Lin CJ, Wu F, Luo K, Zhang H, Lu Z, Feng X. Mercury Uptake, Accumulation, and Translocation in Roots of Subtropical Forest: Implications of Global Mercury Budget. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14154-14165. [PMID: 36150175 DOI: 10.1021/acs.est.2c04217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Plant roots are responsible for transporting large quantities of nutrients in forest ecosystems and yet are frequently overlooked in global assessments of Hg cycling budgets. In this study, we systematically determined the distribution of total Hg mass and its stable isotopic signatures in a subtropical evergreen forest to elucidate sources of Hg in plant root tissues and the associated translocation mechanisms. Hg stored in roots and its isotopic signatures show significant correlations to those found in surrounding soil at various soil depths. The odd mass-independent fractionation (MIF) of root Hg at a shallow soil depth displays a -0.10‰ to -0.50‰ negative transition compared to the values in aboveground woody biomass. The evidence suggests that root Hg is predominantly derived from surrounding soil, rather than translocation of atmospheric uptake via aboveground tissues. The cortex has a more negative mass-dependent fractionation (MDF) of -0.10‰ to -1.20‰ compared to the soil samples, indicating a preferential uptake of lighter isotopes by roots. The similar MDF and odd-MIF signals found in root components imply limited Hg transport in roots. This work highlights that Hg stored in plant roots is not a significant sink of atmospheric Hg. The heterogeneous distribution of Hg mass in roots of various sizes represents a significant uncertainty of current estimates of Hg pool size in forest ecosystems.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Fei Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kang Luo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Zhiyun Lu
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China
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24
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Zhang L, Yin Y, Li Y, Cai Y. Mercury isotope fractionation during methylmercury transport and transformation: A review focusing on analytical method, fractionation characteristics, and its application. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 841:156558. [PMID: 35710002 DOI: 10.1016/j.scitotenv.2022.156558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/04/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
Methylmercury (MeHg), a potent neurotoxin, can be formed, migrated and transformed in environmental compartments, accompanying with unique mass-dependent and mass-independent fractionation of mercury (Hg). These Hg isotope fractionation signals have great potential to probe the transformation and transport of MeHg in aquatic environments. However, the majority of studies to date have focused on total Hg isotopic composition, with less attention to the isotopic fractionation of MeHg due to technical difficulties in analysis, which severely hinders the understanding of MeHg isotopic fractionation and its applications. This review a) evaluates the reported analytical methods for Hg isotopic composition of MeHg, including online and offline measurement techniques; b) summarizes the extent and characteristics of Hg isotopic fractionation during MeHg transport and transformation, focusing on methylation, demethylation, trophic transfer and internal metabolism; and c) briefly discusses several applications of MeHg isotopic fractionation signatures in estimating the extent of photodemethylation, tracing the source of Hg species, and diagnosing reaction mechanisms. Additionally, the existing problems and future directions in MeHg isotope fractionation are highlighted to improve the analytical protocol for Hg isotope fractionation and deepen our understanding of Hg isotope fractionation in the biogeochemical cycling of MeHg.
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Affiliation(s)
- Lian Zhang
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Yanbin Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Yong Cai
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China; Department of Chemistry & Biochemistry, Florida International University, Miami, FL 33199, United States.
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25
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McLagan DS, Schwab L, Wiederhold JG, Chen L, Pietrucha J, Kraemer SM, Biester H. Demystifying mercury geochemistry in contaminated soil-groundwater systems with complementary mercury stable isotope, concentration, and speciation analyses. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1406-1429. [PMID: 34981096 PMCID: PMC9491299 DOI: 10.1039/d1em00368b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Interpretation of mercury (Hg) geochemistry in environmental systems remains a challenge. This is largely associated with the inability to identify specific Hg transformation processes and species using established analytical methods in Hg geochemistry (total Hg and Hg speciation). In this study, we demonstrate the improved Hg geochemical interpretation, particularly related to process tracing, that can be achieved when Hg stable isotope analyses are complemented by a suite of more established methods and applied to both solid- (soil) and liquid-phases (groundwater) across two Hg2+-chloride (HgCl2) contaminated sites with distinct geological and physicochemical properties. This novel approach allowed us to identify processes such as Hg2+ (i.e., HgCl2) sorption to the solid-phase, Hg2+ speciation changes associated with changes in groundwater level and redox conditions (particularly in the upper aquifer and capillary fringe), Hg2+ reduction to Hg0, and dark abiotic redox equilibration between Hg0 and Hg(II). Hg stable isotope analyses play a critical role in our ability to distinguish, or trace, these in situ processes. While we caution against the non-critical use of Hg isotope data for source tracing in environmental systems, due to potentially variable source signatures and overprinting by transformation processes, our study demonstrates the benefits of combining multiple analytical approaches, including Hg isotope ratios as a process tracer, to obtain an improved picture of the enigmatic geochemical behavior and fate of Hg at contaminated legacy sites.
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Affiliation(s)
- D S McLagan
- Institute for Geoecology, Technical University of Braunschweig, 38106 Braunschweig, Germany.
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, M1C1A4, Canada
| | - L Schwab
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - J G Wiederhold
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - L Chen
- Institute for Geoecology, Technical University of Braunschweig, 38106 Braunschweig, Germany.
| | - J Pietrucha
- Institute for Geoecology, Technical University of Braunschweig, 38106 Braunschweig, Germany.
| | - S M Kraemer
- Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria
| | - H Biester
- Institute for Geoecology, Technical University of Braunschweig, 38106 Braunschweig, Germany.
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26
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Zhang K, Zheng W, Sun R, He S, Shuai W, Fan X, Yuan S, Fu P, Deng J, Li X, Wang S, Chen J. Stable Isotopes Reveal Photoreduction of Particle-Bound Mercury Driven by Water-Soluble Organic Carbon during Severe Haze. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10619-10628. [PMID: 35853134 DOI: 10.1021/acs.est.2c01933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Haze with high loading of particles may result in significant enrichment of particle-bound Hg (PBM), potentially impacting the atmospheric Hg transformation and transport. However, the dynamics of Hg transformation and the relative environmental effect during severe haze episodes remain unclear. Here, we report Hg isotopic compositions of atmospheric particles (PM2.5, PM10, and TSP) collected during a severe haze episode in Tianjin, China, to investigate the transformation and fate of Hg during haze events. All severe haze samples display significantly higher Δ199Hg (up to 1.50‰) than global urban PBM, which cannot be explained by primary anthropogenic emissions. The high Δ199Hg is likely caused by photoreduction of PBM promoted by water-soluble organic carbon (WSOC) during the particle accumulation period, as demonstrated by the positive correlations of Δ199Hg with WSOC and relative humidity and confirmed by our laboratory-controlled photoreduction experiment. The results show that, on average, 21% of PBM are likely photoreduced and re-emitted back to the atmosphere as Hg(0), potentially requiring revision of atmospheric Hg budgeting and modeling. This study highlights the release of large portions of PBM back to the gas phase through photoreduction, which needs to be taken into account while evaluating the atmospheric Hg cycle and the relative ecological effects.
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Affiliation(s)
- Ke Zhang
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Wang Zheng
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Ruoyu Sun
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Sheng He
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Wangcai Shuai
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Xiongfei Fan
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Shengliu Yuan
- School of Earth System Science, Tianjin University, Tianjin 300072, China
- Chemistry Department, Trent University, Ontario K9J7B8, Canada
| | - Pingqing Fu
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Junjun Deng
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Xiaodong Li
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Shuxiao Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiubin Chen
- School of Earth System Science, Tianjin University, Tianjin 300072, China
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27
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Li ML, Kwon SY, Poulin BA, Tsui MTK, Motta LC, Cho M. Internal Dynamics and Metabolism of Mercury in Biota: A Review of Insights from Mercury Stable Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9182-9195. [PMID: 35723432 PMCID: PMC9261262 DOI: 10.1021/acs.est.1c08631] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Monitoring mercury (Hg) levels in biota is considered an important objective for the effectiveness evaluation of the Minamata Convention. While many studies have characterized Hg levels in organisms at multiple spatiotemporal scales, concentration analyses alone often cannot provide sufficient information on the Hg exposure sources and internal processes occurring within biota. Here, we review the decadal scientific progress of using Hg isotopes to understand internal processes that modify the speciation, transport, and fate of Hg within biota. Mercury stable isotopes have emerged as a powerful tool for assessing Hg sources and biogeochemical processes in natural environments. A better understanding of the tissue location and internal mechanisms leading to Hg isotope change is key to assessing its use for biomonitoring. We synthesize the current understanding and uncertainties of internal processes leading to Hg isotope fractionation in a variety of biota, in a sequence of better to less studied organisms (i.e., birds, marine mammals, humans, fish, plankton, and invertebrates). This review discusses the opportunities and challenges of using certain forms of biota for Hg source monitoring and the need to further elucidate the physiological mechanisms that control the accumulation, distribution, and toxicity of Hg in biota by coupling new techniques with Hg stable isotopes.
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Affiliation(s)
- Mi-Ling Li
- School
of Marine Science and Policy, University
of Delaware, 201 Robinson Hall, Newark, Delaware 19716, United
States
| | - Sae Yun Kwon
- Division
of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro,
Nam-Gu, Pohang 37673, South Korea
- Institute
for Convergence Research and Education in Advanced Technology, Yonsei University, 85 Songdogwahak-Ro, Yeonsu-Gu, Incheon 21983, South Korea
| | - Brett A. Poulin
- Department
of Environmental Toxicology, University
of California Davis, One Shields Avenue, Davis, California 95616, United States
| | - Martin Tsz-Ki Tsui
- School
of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR 999077, China
| | - Laura C. Motta
- Department
of Chemistry, University at Buffalo, 359 Natural Sciences Complex, Buffalo, New York 14260-3000, United States
| | - Moonkyoung Cho
- Division
of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro,
Nam-Gu, Pohang 37673, South Korea
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28
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Chemical Oxidation and Reduction Pathways of Mercury Relevant to Natural Waters: A Review. WATER 2022. [DOI: 10.3390/w14121891] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mercury (Hg) pollution in the environment is a global issue and the toxicity of mercury depends on its speciation. Chemical redox reactions of mercury in an aquatic environment greatly impact on Hg evasion to the atmosphere and the methylation of mercury in natural waters. Identifying the abiotic redox pathways of mercury relevant to natural waters is important for predicting the transport and fate of Hg in the environment. The objective of this review is to summarize the current state of knowledge on specific redox reactions of mercury relevant to natural waters at a molecular level. The rate constants and factors affecting them, as well as the mechanistic information of these redox pathways, are discussed in detail. Increasing experimental evidence also implied that the structure of natural organic matter (NOM) play an important role in dark Hg(II) reduction, dark Hg(0) oxidation and Hg(II) photoreduction in the aquatic environment. Significant photooxidation pathways of Hg(0) identified are Hg(0) photooxidation by hydroxyl radical (OH•) and by carbonate radical (CO3−•). Future research needs on improving the understanding of Hg redox cycling in natural waters are also proposed.
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29
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Xia S, Yuan W, Lin L, Yang X, Feng X, Li X, Liu X, Chen P, Zeng S, Wang D, Su Q, Wang X. Latitudinal gradient for mercury accumulation and isotopic evidence for post-depositional processes among three tropical forests in Southwest China. JOURNAL OF HAZARDOUS MATERIALS 2022; 429:128295. [PMID: 35074747 DOI: 10.1016/j.jhazmat.2022.128295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/04/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Tropical forest contributes to > 50% of global litterfall mercury (Hg) inputs and surface soil Hg storage, while with limited understanding of Hg biogeochemical processes. In this study, we displayed the 5-m resolution of Hg spatial distribution in three 1-ha tropical forest plots across the latitudinal gradient in Southwest China, and determined Hg isotopic signatures to understand factors driving Hg spatial distribution and sequestration processes. Our results show that tropical forest at the lowest latitude has the highest litterfall Hg input (74.95 versus 34.14-56.59 μg m-2 yr-1 at higher latitude plots), but the smallest surface soil Hg concentration (2-3 times smaller than at higher latitude sites). Hg isotopic evidence indicates that the decreasing climate mediated microbial Hg reduction in forest floor leads to the increasing Hg accumulation along the latitudinal gradient in three tropical forests. The terrain induced indirect effects by influencing litterfall Hg inputs, soil organic matters distribution and interplays between surface and deep soils drive the heterogeneity of surface soil Hg distribution within each sampling plot. Our results highlight though the elevated litterfall Hg inputs, the distinct post-depositional reductions induced Hg loss would remarkedly decrease atmospheric Hg net sink in tropical forest.
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Affiliation(s)
- Shangwen Xia
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Luxiang Lin
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China; National Forest Ecosystem Research Station at Xishuangbanna, Mengla 666300, Yunnan, China
| | - Xiaodong Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666300, Yunnan, China; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xianming Li
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xu Liu
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Peijia Chen
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Shufang Zeng
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Dingyong Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qizhao Su
- Mengla Institute of Conservation, Xishuangbanna Administration of Nature Reserves, Mengla 666300, Yunan, China
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
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30
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Živković I, Humphreys MP, Achterberg EP, Dumousseaud C, Woodward EMS, Bojanić N, Šolić M, Bratkič A, Kotnik J, Vahčič M, Obu Vazner K, Begu E, Fajon V, Shlyapnikov Y, Horvat M. Enhanced mercury reduction in the South Atlantic Ocean during carbon remineralization. MARINE POLLUTION BULLETIN 2022; 178:113644. [PMID: 35413504 DOI: 10.1016/j.marpolbul.2022.113644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/26/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
Mercury (Hg) in seawater is subject to interconversions via (photo)chemical and (micro)biological processes that determine the extent of dissolved gaseous mercury (DGM) (re)emission and the production of monomethylmercury. We investigated Hg speciation in the South Atlantic Ocean on a GEOTRACES cruise along a 40°S section between December 2011 and January 2012 (354 samples collected at 24 stations from surface to 5250 m maximum depth). Using statistical analysis, concentrations of methylated mercury (MeHg, geometric mean 35.4 fmol L-1) were related to seawater temperature, salinity, and fluorescence. DGM concentrations (geometric mean 0.17 pmol L-1) were related to water column depth, concentrations of macronutrients and dissolved inorganic carbon (DIC). The first-ever observed linear correlation between DGM and DIC obtained from high-resolution data indicates possible DGM production by organic matter remineralization via biological or dark abiotic reactions. DGM concentrations projected from literature DIC data using the newly discovered DGM-DIC relationship agreed with published DGM observations.
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Affiliation(s)
- Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia.
| | - Matthew P Humphreys
- NIOZ Royal Netherlands Institute for Sea Research, Department of Ocean Systems (OCS), P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands
| | - Eric P Achterberg
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany
| | - Cynthia Dumousseaud
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, United Kingdom
| | | | - Natalia Bojanić
- Laboratory of Plankton and Shellfish Toxicity, Institute of Oceanography and Fisheries, Šetalište I. Meštrovića 63, 21000 Split, Croatia
| | - Mladen Šolić
- Laboratory of Marine Microbiology, Institute of Oceanography and Fisheries, Šetalište I. Meštrovića 63, 21000 Split, Croatia
| | - Arne Bratkič
- Chemistry Department, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Elsene, Belgium
| | - Jože Kotnik
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Mitja Vahčič
- Joint Research Centre, European Commission, Retieseweg 111, 2440 Geel, Belgium
| | - Kristina Obu Vazner
- Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia; Ecological Engineering Institute, Ljubljanska ulica 9, 2000 Maribor, Slovenia
| | - Ermira Begu
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Vesna Fajon
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Yaroslav Shlyapnikov
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
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31
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Liu C, Fu X, Xu Y, Zhang H, Wu X, Sommar J, Zhang L, Wang X, Feng X. Sources and Transformation Mechanisms of Atmospheric Particulate Bound Mercury Revealed by Mercury Stable Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5224-5233. [PMID: 35385257 DOI: 10.1021/acs.est.1c08065] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This study examined the isotopic composition of particulate bound mercury (PBM) in 10 Chinese megacities and explored the associated sources and transformation mechanisms. PBM in these cities was characterized by negative δ202Hg (mean: -2.00 to -0.78‰), slightly negative to highly positive Δ199Hg (mean: -0.04 to 0.47‰), and slightly positive Δ200Hg (mean: 0.02 to 0.06‰) values. The positive PBM Δ199Hg signatures were likely caused by physiochemical reactions in aerosols. The Δ199Hg/Δ201Hg ratio varied from 0.94 to 1.39 in the cities and increased with the increase in the corresponding mean Δ199HgPBM value. We speculate that, in addition to the photoreduction of oxidized Hg, other transformation mechanisms in aerosols (e.g., isotope exchange, complexation, and oxidation, which express nuclear volume effects) also shape the Δ199HgPBM signatures in the present study. These processes are likely enhanced in the presence of strong gas-particle partitioning of gaseous oxidized Hg (GOM) and elevated levels of redox active metals (e.g., Fe), halides, and elemental carbon. Based on Δ200HgPBM data presented in this and previous studies, we estimate that large proportions (∼47 ± 22%) of PBM were sourced from the oxidation of gaseous elemental Hg followed by the partitioning of GOM onto aerosols globally, indicating the transformation of Hg(0) to PBM as an important sink of atmospheric Hg(0).
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Affiliation(s)
- Chen Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Yue Xu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xian Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto M3H 5T4, Ontario, Canada
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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32
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Huang S, Jiang R, Song Q, Zhao Y, Lv S, Zhang Y, Huo Y, Chen Y. The Hg behaviors in mangrove ecosystems revealed by Hg stable isotopes: a case study of Maowei mangrove. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:25349-25359. [PMID: 34843054 DOI: 10.1007/s11356-021-17744-4] [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: 08/13/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
As one of the most productive marine ecosystems in the tropics and subtropics, mangroves are an important part of the global mercury (Hg) cycling. The environmental processes and effects of Hg in mangroves are complex and affect human Hg exposure, and it is crucial to understand Hg behaviors in the mangrove ecosystem. However, clarifying Hg behaviors in the mangrove ecosystem remains difficult because of an insufficient understanding of the dominant pathways. In this study, measurements of mercury (Hg) concentration and isotope ratios in sediment and plant tissues from a mangrove wetland were used to investigate Hg isotope fractionation in mangrove plants and sediments. Spatial patterns in Hg concentration and isotope signatures indicate that Hg re-emission in the sediment was suppressed by mangrove plants. The ratio of Δ199Hg/Δ201Hg was 0.93 for all sediments, indicating that Hg mass-independent fractionation in the mangrove ecosystem was primarily affected by photoreduction, while the ratios of Δ199Hg/Δ201Hg and Δ199Hg/δ202Hg for plant tissues suggested that natural organic matter reduction of Hg(II) was occurred in the plants. The distinct positive Δ199Hg values found in mangrove plants were supposed to be the results of the unique physiological characteristics of mangroves. The exterior Hg sources from atmosphere and seawater emphasize the role of mangrove ecosystems in the global Hg biogeochemistry. Our study highlights the distinct Hg isotope signatures in the mangrove from that in forests and indicates unique Hg behaviors in the mangrove ecosystem.
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Affiliation(s)
- Shuyuan Huang
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Ronggen Jiang
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
| | - Qingyong Song
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
| | - Yuhan Zhao
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Supeng Lv
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
| | - Yuanbiao Zhang
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China.
| | - Yunlong Huo
- Ministry of Natural Resources, Third Institute of Oceanography, Xiamen, 361005, China
| | - Yaojin Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China
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33
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Chen X, Zheng L, Sun R, Liu S, Li C, Chen Y, Xu Y. Mercury in sediment reflecting the intensive coal mining activities: Evidence from stable mercury isotopes and Bayesian mixing model analysis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 234:113392. [PMID: 35272196 DOI: 10.1016/j.ecoenv.2022.113392] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Severe environmental issues are caused by long-term coal mining activities; however, the process of mercury (Hg) response in mining subsidence area sediments (MSAS) is still unclear, and direct evidence showing the relationship between Hg accumulation mechanism in sediments and mining activities is lacking. In this study, the characteristics of total mercury (THg) content in MSAS were investigated. Moreover, Hg isotopes were obtained to determine the main sources and environmental process of mercury in MSAS, and a MixSIAR mixing model was first used to estimate the potential Hg sources. The THg content ranged from 27.5 to 113.9 ng/g, with a mean of 65.8 ± 29.4 ng/g, exceeding the local soil background value (19.7 ng/g). The Hg in MSAS was affected by clay and organic matter. The Δ199Hg and Δ201Hg in the sediments varied from - 0.05-0.05‰ (mean: -0.01 ± 0.03‰) and - 0.07-0.01‰ (mean: -0.02 ± 0.03‰), respectively, with the fitting results suggesting that a photochemical reaction occurred in some of the Hg in the sediments prior to deposition. The results of the MixSIAR mixing model revealed that the Hg in MSAS was mainly derived from gangue, soil erosion, coal, fly ash, and feed, and their corresponding percentage contribution was 51.5 ± 9.6%, 23.8 ± 13.1%, 13.9 ± 7.9%, 8.1 ± 5.4%, and 3.1 ± 1.4%, respectively. Hg isotopes can be used to trace the transport and transformation of environmental pollutants, and this may provide an important reference for the assessment and prevention of Hg pollution in typical areas such as coal mining and coal-fired.
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Affiliation(s)
- Xing Chen
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei 230601, Anhui, China
| | - Liugen Zheng
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei 230601, Anhui, China.
| | - Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Sikui Liu
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei 230601, Anhui, China
| | - Chang Li
- School of Resources and Environmental Engineering, Anhui University, Anhui Province Engineering Laboratory for Mine Ecological Remediation, Hefei 230601, Anhui, China
| | - Yongchun Chen
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan 232001, Anhui, China
| | - Yanfei Xu
- National Engineering Laboratory of Coal Mine Ecological Environment Protection, Huainan 232001, Anhui, China
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34
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Campeau A, Eklöf K, Soerensen AL, Åkerblom S, Yuan S, Hintelmann H, Bieroza M, Köhler S, Zdanowicz C. Sources of riverine mercury across the Mackenzie River Basin; inferences from a combined HgC isotopes and optical properties approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150808. [PMID: 34637879 DOI: 10.1016/j.scitotenv.2021.150808] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
The Arctic environment harbors a complex mosaic of mercury (Hg) and carbon (C) reservoirs, some of which are rapidly destabilizing in response to climate warming. The sources of riverine Hg across the Mackenzie River basin (MRB) are uncertain, which leads to a poor understanding of potential future release. Measurements of dissolved and particulate mercury (DHg, PHg) and carbon (DOC, POC) concentration were performed, along with analyses of Hg stable isotope ratios (incl. ∆199Hg, δ202Hg), radiocarbon content (∆14C) and optical properties of DOC of river water. Isotopic ratios of Hg revealed a closer association to terrestrial Hg reservoirs for the particulate fraction, while the dissolved fraction was more closely associated with atmospheric deposition sources of shorter turnover time. There was a positive correlation between the ∆14C-OC and riverine Hg concentration for both particulate and dissolved fractions, indicating that waters transporting older-OC (14C-depleted) also contained higher levels of Hg. In the dissolved fraction, older DOC was also associated with higher molecular weight, aromaticity and humic content, which are likely associated with higher Hg-binding potential. Riverine PHg concentration increased with turbidity and SO4 concentration. There were large contrasts in Hg concentration and OC age and quality among the mountain and lowland sectors of the MRB, which likely reflect the spatial distribution of various terrestrial Hg and OC reservoirs, including weathering of sulfate minerals, erosion and extraction of coal deposits, thawing permafrost, forest fires, peatlands, and forests. Results revealed major differences in the sources of particulate and dissolved riverine Hg, but nonetheless a common positive association with older riverine OC. These findings reveal that a complex mixture of Hg sources, supplied across the MRB, will contribute to future trends in Hg export to the Arctic Ocean under rapid environmental changes.
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Affiliation(s)
- Audrey Campeau
- Department of Earth Sciences, Uppsala University, Sweden; Depatment of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
| | - Karin Eklöf
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anne L Soerensen
- Department of Environmental Research and Monitoring, Swedish Museum of Natural History, Sweden
| | - Staffan Åkerblom
- Statistiska centralbyrån (SCB), Statistic Sweden, Stockholm, Sweden
| | - Shengliu Yuan
- Water Quality Center, Trent University, Peterborough, Ontario, Canada
| | - Holger Hintelmann
- Water Quality Center, Trent University, Peterborough, Ontario, Canada
| | - Magdalena Bieroza
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Stephan Köhler
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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35
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Zhu W, Fu X, Zhang H, Liu C, Skyllberg U, Sommar J, Yu B, Feng X. Mercury Isotope Fractionation during the Exchange of Hg(0) between the Atmosphere and Land Surfaces: Implications for Hg(0) Exchange Processes and Controls. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1445-1457. [PMID: 34964623 DOI: 10.1021/acs.est.1c05602] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Atmosphere-surface exchange of elemental mercury (Hg(0)) is a vital component in global Hg cycling; however, Hg isotope fractionation remains largely unknown. Here, we report Hg isotope fractionation during air-surface exchange from terrestrial surfaces at sites of background (two) and urban (two) character and at five sites contaminated by Hg mining. Atmospheric Hg(0) deposition to soils followed kinetic isotope fractionation with a mass-dependent (MDF) enrichment factor of -4.32‰, and negligible mass-independent fractionation (MIF). Net Hg(0) emission generated average MDF enrichment factors (ε202Hg) of -0.91, -0.59, 1.64, and -0.42‰ and average MIF enrichment factors (E199Hg) of 0.07, -0.20, -0.14, and 0.21‰ for urban, background, and Hg mining soils and cinnabar tailing, respectively. Positive correlations between ε202Hg and ambient Hg(0) concentration indicate that the co-occurring Hg(0) deposition (accounting for 10-39%) in a regime of net soil emission grows with ambient Hg(0). The MIF of Hg(0) emission from soils (E199Hg range -0.27 to 0.14‰, n = 8) appears to be overall controlled by the photochemical reduction of kinetically constrained Hg(II) bonded to O ligands in background soils, while S ligands may have been more important in Hg mining area soils. In contrast, the small positive MIF of Hg(0) emission from cinnabar ore tailing (mean E199Hg = 0.21‰) was likely controlled by abiotic nonphotochemical reduction and liquid Hg(0) evaporation. This research provides critical observational constraints on understanding the Hg(0) isotope signatures released from and deposited to terrestrial surfaces and highlight stable Hg isotopes as a powerful tool for resolving atmosphere-surface exchange processes.
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Affiliation(s)
- Wei Zhu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ulf Skyllberg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Ben Yu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China
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36
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Huang Q, He X, Huang W, Reinfelder JR. Mass-Independent Fractionation of Mercury Isotopes during Photoreduction of Soot Particle Bound Hg(II). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13783-13791. [PMID: 34623141 DOI: 10.1021/acs.est.1c02679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Soot and mercury (Hg) are two notorious air pollutants, and the fate and transport of Hg may be affected by soot at various scales in the environment as soot may be both a carrier and a reactant for active Hg species. This study was designed to quantify photoreduction of Hg(II) in the presence of soot and the associated Hg isotope fractionation under both atmospheric aerosol and aqueous conditions (water-saturated). Photoreduction experiments were conducted with diesel soot particulate matter under controlled temperature and relative humidity (RH) conditions using a flow-through semibatch reactor system. Mass-dependent fractionation resulted in the enrichment of heavier Hg isotopes in the remaining Hg(II) with enrichment factors (ε202Hg) of 1.48 ± 0.02‰ (±2 standard deviation) to 1.75 ± 0.05‰ for aerosol-phase reactions (RH 28-68%) and from 1.26 ± 0.11 to 1.50 ± 0.04‰ for aqueous-phase reactions. Positive odd mass-independent fractionation (MIF) was observed in aqueous-phase reactions, resulting in Δ199Hg values for reactant Hg(II) as high as 5.29‰, but negative odd-MIF occurred in aerosol-phase reactions, in which Δ199Hg values of reactant Hg(II) varied from -1.02 to 0‰. The average ratio of Δ199Hg/Δ201Hg (1.1) indicated that under all conditions, MIF was dominated by magnetic isotope effects during photoreduction of Hg(II). Increasing RH resulted in higher reduction rates but lower extents of negative MIF in the aerosol-phase experiments, suggesting that the reduction of soot particle-bound Hg(II) was responsible for the observed negative odd-MIF. Our results suggest that mass-independent Hg isotope fractionation during Hg(II) photoreduction varies with soot aerosol water content and that Hg-stable isotope ratios may be used to understand the transformational histories of aerosol-bound Hg(II) in the environment.
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Affiliation(s)
- Qiang Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, Guizhou, China
- Department of Environmental Sciences, Rutgers University, New Brunswick 08901, New Jersey, United States
| | - Xiaoshuai He
- Department of Environmental Sciences, Rutgers University, New Brunswick 08901, New Jersey, United States
| | - Weilin Huang
- Department of Environmental Sciences, Rutgers University, New Brunswick 08901, New Jersey, United States
| | - John R Reinfelder
- Department of Environmental Sciences, Rutgers University, New Brunswick 08901, New Jersey, United States
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37
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Zhao H, Meng B, Sun G, Lin CJ, Feng X, Sommar J. Chemistry and Isotope Fractionation of Divalent Mercury during Aqueous Reduction Mediated by Selected Oxygenated Organic Ligands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13376-13386. [PMID: 34520177 DOI: 10.1021/acs.est.1c03171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We have investigated the chemistry and Hg isotope fractionation during the aqueous reduction of HgII by oxalic acid, p-quinone, quinol, and anthraquinone-2,6-disulfonate (AQDS), a derivate of anthraquinone (AQ) that is found in secondary organic aerosols (SOA) and building blocks of natural organic matter (NOM). Each reaction was examined for the effects of light, pH, and dissolved O2. Using an excess of ligand, UVB photolysis of HgII was seen to follow pseudo-first-order kinetics, with the highest rate of ∼10-3 s-1 observed for AQDS and oxalic acid. Mass-dependent fractionation (MDF) occurs by the normal kinetic isotope effect (KIE). Only the oxalate ion, rather than oxalic acid, is photoreactive when present in HgC2O4, which decomposes via two separate pathways distinguishable by isotope anomalies. Upon UVB photolysis, only the reduction mediated by AQDS results in a large odd number mass-independent fractionation (odd-MIF) signified by enrichment of odd isotopes in the reactant. Consistent with the rate, MDF, and odd-MIF reported for fulvic acid, our AQDS result confirms previous assumptions that quinones control HgII reduction in NOM-rich waters. Given the magnitude of odd-MIF triggered via a radical pair mechanism and the significant rate in the presence of air, reduction of HgII by photoproducts of AQDS may help explain the positive odd-MIF observed in ambient aerosols depleted of HgII.
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Affiliation(s)
- Huifang Zhao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- School of Geography & Environmental Science, Guizhou Normal University, Guiyang 550025, China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Guangyi Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Yuan W, Wang X, Lin CJ, Sommar JO, Wang B, Lu Z, Feng X. Quantification of Atmospheric Mercury Deposition to and Legacy Re-emission from a Subtropical Forest Floor by Mercury Isotopes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:12352-12361. [PMID: 34449213 DOI: 10.1021/acs.est.1c02744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Air-soil exchange of elemental mercury vapor (Hg0) is an important component in the budget of the global mercury cycle. However, its mechanistic detail is poorly understood. In this study, stable Hg isotopes in air, soil, and pore gases are characterized in a subtropical evergreen forest to understand the mechanical features of the air-soil Hg0 exchange. Strong HgII reduction in soil releases Hg0 to pore gas during spring-autumn but diminishes in winter, limiting the evasion in cold seasons. Δ199Hg in air modified by the Hg0 efflux during flux chamber measurement exhibit seasonality, from -0.33 ± 0.05‰ in summer to -0.08 ± 0.05‰ in winter. The observed seasonal variation is caused by a strong pore-gas driven soil efflux caused by photoreduction in summer, which weakens significantly in winter. The annual Hg0 gross deposition is 42 ± 33 μg m-2 yr-1, and the corresponding Hg0 evasion from the forest floor is 50 ± 41 μg m-2 yr-1. The results of this study, although still with uncertainty, offer new insights into the complexity of the air-surface exchange of Hg0 over the forest land for model implementation in future global assessments.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Jonas Olof Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Bo Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyun Lu
- National Forest Ecosystem Research Station at Ailaoshan, Jingdong, Yunnan 676209, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xi'an 710061, China
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Stable Isotope Fractionation Reveals Similar Atomic-Level Controls during Aerobic and Anaerobic Microbial Hg Transformation Pathways. Appl Environ Microbiol 2021; 87:e0067821. [PMID: 34232740 DOI: 10.1128/aem.00678-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mercury (Hg) is a global pollutant and potent neurotoxin that bioaccumulates in food webs as monomethylmercury (MeHg). The production of MeHg is driven by anaerobic and Hg redox cycling pathways, such as Hg reduction, which control the availability of Hg to methylators. Anaerobes play an important role in Hg reduction in methylation hot spots, yet their contributions remain underappreciated due to how challenging these pathways are to study in the absence of dedicated genetic targets and low levels of Hg0 in anoxic environments. In this study, we used Hg stable isotope fractionation to explore Hg reduction during anoxygenic photosynthesis and fermentation in the model anaerobe Heliobacterium modesticaldum Ice1. We show that cells preferentially reduce lighter Hg isotopes in both metabolisms, leading to mass-dependent fractionation, but mass-independent fractionation commonly induced by UV-visible light is absent. Due to the variability associated with replicate experiments, we could not discern whether dedicated physiological processes drive Hg reduction during photosynthesis and fermentation. However, we demonstrate that fractionation is affected by the interplay between pathways controlling Hg recruitment, accessibility, and availability alongside metabolic redox reactions. The combined contributions of these processes lead to isotopic enrichment during anoxygenic photosynthesis that is in between the values reported for anaerobic respiratory microbial Hg reduction and abiotic photoreduction. Isotope enrichment during fermentation is closer to what has been observed in aerobic bacteria that reduce Hg through dedicated detoxification pathways. Our work suggests that similar controls likely underpin diverse microbe-mediated Hg transformations that affect Hg's fate in oxic and anoxic habitats. IMPORTANCE Anaerobic and photosynthetic bacteria that reduce mercury affect mercury delivery to microbes in methylation sites that drive bioaccumulation in food webs. Anaerobic mercury reduction pathways remain underappreciated in the current view of the global mercury cycle because they are challenging to study, bearing no dedicated genetic targets to establish physiological mechanisms. In this study, we used stable isotopes to characterize the physiological processes that control mercury reduction during photosynthesis and fermentation in the model anaerobe Heliobacterium modesticaldum Ice1. The sensitivity of isotope analyses highlighted the subtle contribution of mercury uptake to the isotope signature associated with anaerobic mercury reduction. When considered alongside the isotope signatures associated with microbial pathways for which genetic determinants have been identified, our findings underscore the narrow range of isotope enrichment that is characteristic of microbial mercury transformations. This suggests that there are common atomic-level controls for biological mercury transformations across a broad range of geochemical conditions.
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Fu X, Jiskra M, Yang X, Marusczak N, Enrico M, Chmeleff J, Heimbürger-Boavida LE, Gheusi F, Sonke JE. Mass-Independent Fractionation of Even and Odd Mercury Isotopes during Atmospheric Mercury Redox Reactions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10164-10174. [PMID: 34213316 DOI: 10.1021/acs.est.1c02568] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mass-independent fractionation (MIF) of stable even mass number mercury (Hg) isotopes is observed in rainfall and gaseous elemental Hg0 globally and is used to quantify atmospheric Hg deposition pathways. The chemical reaction and underlying even-Hg MIF mechanism are unknown however and speculated to be caused by Hg photo-oxidation on aerosols at the tropopause. Here, we investigate the Hg isotope composition of free tropospheric Hg0 and oxidized HgII forms at the high-altitude Pic du Midi Observatory. We find that gaseous oxidized Hg has positive Δ199Hg, Δ201Hg, and Δ200Hg and negative Δ204Hg signatures, similar to rainfall Hg, and we document rainfall Hg Δ196Hg to be near zero. Cloud water and rainfall Hg show an enhanced odd-Hg MIF of 0.3‰ compared to gaseous oxidized HgII, potentially indicating the occurrence of in-cloud aqueous HgII photoreduction. Diurnal MIF observations of free tropospheric Hg0 show how net Hg0 oxidation in high-altitude air masses leads to opposite even- and odd-MIF in Hg0 and oxidized HgII. We speculate that even-Hg MIF takes place by a molecular magnetic isotope effect during HgII photoreduction on aerosols that involves magnetic halogen nuclei. A Δ200Hg mass balance suggests that global Hg deposition pathways in models are likely biased toward HgII deposition. We propose that Hg cycling models could accommodate the Hg-isotope constraints on emission and deposition fluxes.
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Affiliation(s)
- Xuewu Fu
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Martin Jiskra
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
- Environmental Geosciences, University of Basel, Basel 4001, Switzerland
| | - Xu Yang
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
| | - Nicolas Marusczak
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
| | - Maxime Enrico
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
| | - Jérôme Chmeleff
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
| | - Lars-Eric Heimbürger-Boavida
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
- Mediterranean Institute of Oceanography, Aix Marseille Université, CNRS/IRD, Université de Toulon, IRD, Marseille 13288, France
| | - François Gheusi
- Laboratoire d'Aérologie, CNRS/IRD/Université de Toulouse, Toulouse 31000, France
| | - Jeroen E Sonke
- Géosciences Environnement Toulouse, CNRS/IRD/CNRS/Université de Toulouse, Toulouse 31000, France
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Crowther ER, Demers JD, Blum JD, Brooks SC, Johnson MW. Use of sequential extraction and mercury stable isotope analysis to assess remobilization of sediment-bound legacy mercury. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:756-775. [PMID: 33970175 DOI: 10.1039/d1em00019e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The goal of this project was to assess how anthropogenic legacy mercury (Hg) retained in streambed sediment may be remobilized to stream water. To do this, we performed sequential extractions and Hg isotope analyses on streambed sediment collected along the length of East Fork Poplar Creek, a point-source contaminated stream in Oak Ridge, Tennessee, USA. Legacy Hg within streambed sediment appears to have been isotopically fractionated by equilibrium isotope effects driven by isotope exchange between co-existing Hg(0) and Hg(ii) species, potentially over-printing fractionation patterns that would have been imparted by kinetic redox reactions. Weakly-bound and recalcitrant sediment Hg pools were isotopically similar to one another, suggesting that small amounts of recalcitrant Hg may be released and then rapidly and weakly re-adsorbed onto the sediment. This weakly-bound Hg pool appears to contribute dissolved Hg to the hyporheic pore water, which may subsequently enter the surface flow. The isotopic composition of the organically-bound sediment Hg pools, as well as biofilm and suspended particulates, converged with that of the weakly-bound and recalcitrant sediment Hg pools along the flow path. This appears to be indicative of both physical mixing with streambed sediment and the transfer of weakly-bound sediment Hg into biofilm and suspended particulates, followed by re-incorporation into the organically-bound sediment Hg pool. Overall, these results provide evidence that legacy Hg in the streambed is remobilized, enters the stream water as dissolved Hg, and may be incorporated into streambed biofilm, which constitutes a basal resource within the stream ecosystem.
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Affiliation(s)
- Elizabeth R Crowther
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI 48109-1005, USA.
| | - Jason D Demers
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI 48109-1005, USA.
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI 48109-1005, USA.
| | - Scott C Brooks
- Environmental Science Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6038, USA
| | - Marcus W Johnson
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI 48109-1005, USA.
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Enrico M, Balcom P, Johnston DT, Foriel J, Sunderland EM. Simultaneous combustion preparation for mercury isotope analysis and detection of total mercury using a direct mercury analyzer. Anal Chim Acta 2021; 1154:338327. [PMID: 33736793 DOI: 10.1016/j.aca.2021.338327] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/11/2021] [Accepted: 02/14/2021] [Indexed: 10/22/2022]
Abstract
Mercury (Hg) stable isotope signatures are widely used to understand Hg cycling in the environment. Sample preparation methods for determining Hg isotope ratios by CV-MC-ICP-MS vary widely among laboratory facilities and sample types. Here, we present a novel and rapid method for preparing solid samples prior to determining Hg isotope composition. We use a direct Hg analyzer (that measures total Hg) for sample combustion, amalgamation and analysis. During the thermal release of Hg from the amalgamator and following detection, the analyte gas enters a trapping solution consisting of 10% HCl/BrCl (5:1, vol/vol). We find Hg blank values are less than 1% of the Hg introduced during sample analysis, Hg detection is not altered by modifying the system, and more than 90% of the introduced Hg is recovered in the trapping solution. Hg isotope results are statistically indistinguishable from accepted values for previously published certified reference materials and uncertainty of 2σ (0.05-0.12‰) is similar to the solution standard RM8610 (2σ = 0.09‰). This new method allows for solid sample preparation for Hg isotope analysis in under 15 min. It has the additional advantage of minimizing use of sample mass during simultaneous detection and preparation.
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Affiliation(s)
- Maxime Enrico
- Harvard John A. Paulson School of Engineering & Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA, 02138, USA.
| | - Prentiss Balcom
- Harvard John A. Paulson School of Engineering & Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA, 02138, USA
| | - David T Johnston
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St, Cambridge, MA, 02138, USA
| | - Julien Foriel
- Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St, Cambridge, MA, 02138, USA
| | - Elsie M Sunderland
- Harvard John A. Paulson School of Engineering & Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA, 02138, USA; Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St, Cambridge, MA, 02138, USA
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43
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Lu Z, Yuan W, Luo K, Wang X. Litterfall mercury reduction on a subtropical evergreen broadleaf forest floor revealed by multi-element isotopes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115867. [PMID: 33160734 DOI: 10.1016/j.envpol.2020.115867] [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: 08/24/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Litterfall mercury (Hg) deposition is the dominant source of soil Hg in forests. Identifying reduction processes and tracking the fate of legacy Hg on forest floor are challenging tasks. Interplays between isotopes of carbon (C) and nitrogen (N) may shed some lights on Hg biogeochemical processes because their biogeochemical cycling closely links with organic matters. Isotope measurements at the evergreen broadleaf forest floor at Mt. Ailao (Mountain Ailao) display that δ202Hg and Δ199Hg both significantly correlate with δ13C and δ15N in soil profiles. Data analysis results show that microbial reduction is the dominant process for the distinct δ202Hg shift (up to ∼1.0‰) between Oi and 0-10 cm surface mineral soil, and dark abiotic organic matter reduction is the main cause for the Δ199Hg shift (∼-0.18‰). Higher N in foliage leads to greater Hg concentration, and Hg0 re-emission via microbial reduction on forest floor is likely linked to N release and immobilization on forest floor. We thus suggest that the enhanced N deposition in global forest ecosystems can potentially influence Hg uptake by vegetation and litter Hg sequestration on forest floor.
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Affiliation(s)
- Zhiyun Lu
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Xishuangbanna, Yunnan, 666303, China; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan, 676200, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Kang Luo
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Xishuangbanna, Yunnan, 666303, China; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences, Jingdong, Yunnan, 676200, China
| | - Xun Wang
- College of Resources and Environment, Southwest University, Chongqing, 400715, China.
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Bonsignore M, Manta DS, Barsanti M, Conte F, Delbono I, Horvat M, Quinci EM, Schirone A, Shlyapnikov Y, Sprovieri M. Mercury isotope signatures in sediments and marine organisms as tracers of historical industrial pollution. CHEMOSPHERE 2020; 258:127435. [PMID: 32947671 DOI: 10.1016/j.chemosphere.2020.127435] [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: 02/28/2020] [Revised: 06/09/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
Isotopic composition of mercury (Hg) in marine organisms and sediment cores was used to identify sources and reconstruct historical trends of contamination in the coastal-marine area of Rosignano Solvay (Italy), affected by Hg pollution from a chlor-alkali plant on the near land. Sediments show a wide range of Hg concentration and Hg isotope signatures. Particularly, coupled Hg concentration and δ202Hg values trace inputs from different sources. The two depth-profiles clearly indicate three distinct periods: "pre-industrial" (before 1941), "industrial" (between 1941 and 2007) and "post-industrial" (after 2007) ages. This is also corroborated by sediment chronology, using 210Pb dating method, validated through 137Cs. Marine organisms are characterized by Hg isotope signatures comparable to "post-industrial" surface sediments. Notably, specimens of Mullus spp. evidence isotope composition comparable to the "industrial" sediments, thus suggesting a still active role of those sediments as source of Hg for the benthic fish compartment. The small amount of MIF and the Δ199Hg/Δ201Hg ratio recorded in organisms are reasonably consistent with limited processes of MMHg demethylation in the water column.
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Affiliation(s)
- Maria Bonsignore
- IAS-CNR - National Research Council of Italy IAS - Institute of Anthropic Impacts and Sustainability in marine environment, Capo Granitola, Italy.
| | - Daniela Salvagio Manta
- IAS-CNR - National Research Council of Italy IAS - Institute of Anthropic Impacts and Sustainability in marine environment, Lungomare Cristoforo Colombo 452, 90149 Palermo, Italy
| | - Mattia Barsanti
- ENEA - Italian National Agency for new technologies, energy and sustainable economic development, SSPT - Department for Sustainability of Production and Territorial Systems, La Spezia, Italy
| | - Fabio Conte
- ENEA - Italian National Agency for new technologies, energy and sustainable economic development, SSPT - Department for Sustainability of Production and Territorial Systems, La Spezia, Italy
| | - Ivana Delbono
- ENEA - Italian National Agency for new technologies, energy and sustainable economic development, SSPT - Department for Sustainability of Production and Territorial Systems, La Spezia, Italy
| | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Enza Maria Quinci
- IAS-CNR - National Research Council of Italy IAS - Institute of Anthropic Impacts and Sustainability in marine environment, Capo Granitola, Italy
| | - Antonio Schirone
- ENEA - Italian National Agency for new technologies, energy and sustainable economic development, SSPT - Department for Sustainability of Production and Territorial Systems, La Spezia, Italy
| | | | - Mario Sprovieri
- IAS-CNR - National Research Council of Italy IAS - Institute of Anthropic Impacts and Sustainability in marine environment, Capo Granitola, Italy
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Li C, Sun J, Shi J, Liang H, Cao Q, Li Z, Gao Y. Mercury sources in a subterranean spontaneous combustion area. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110863. [PMID: 32544749 DOI: 10.1016/j.ecoenv.2020.110863] [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: 05/07/2020] [Revised: 06/03/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Mercury is a toxic, persistent, and mobile contaminant. Coal spontaneous combustion are widely distributed in the world and releases a great deal of Hg. Identifying the burning coal seam is crucial for quickly extinguishing a coalfield fire. Mercury isotopes can be effective for identifying burning coal seams and beneficial for combating coal spontaneous combustion. In this study, Hg isotopic ratios of coal, topsoil, dustfall, sand, coal fire sponges (CFS), and n-topsoil (topsoil near the CFS) from coal fire area No. 9 in the Wuda coalfield were determined using multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS). Analysis of the correlation coefficients between the δ202Hg and Hg concentrations and the low-temperature ashes indicate that the higher mineral concentration in coal seam No. 9 not only increases the Hg concentration but also leads to more positive δ202Hg values compared to those for coal seam No. 10. By analyzing the Hg isotope characterizations in coal seam No. 9 and No. 10, we determined that Hg isotope characterizations can be useful for discriminating different coal seam Hg values in a coalfield. Significant mass-dependent fractionation (MDF) occur in the coal burning. The fractionation effect of burning and absorption process can play a key role in the δ202Hg more negative of ground surface samples. If Hg isotopes is added, the effect of coal-fire monitoring may be better. In addition, these finding could be used to better understand the transport and cycling of Hg.
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Affiliation(s)
- Chunhui Li
- MOE Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China.
| | - Jiacong Sun
- MOE Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jiyan Shi
- MOE Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Handong Liang
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China.
| | - Qingyi Cao
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China
| | - Zhiwei Li
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing, 100083, China
| | - Yu Gao
- MOE Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
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Li C, Chen J, Angot H, Zheng W, Shi G, Ding M, Du Z, Zhang Q, Ma X, Kang S, Xiao C, Ren J, Qin D. Seasonal Variation of Mercury and Its Isotopes in Atmospheric Particles at the Coastal Zhongshan Station, Eastern Antarctica. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11344-11355. [PMID: 32822538 DOI: 10.1021/acs.est.0c04462] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is a globally spread trace metal due to its long atmospheric residence time. Yet, our understanding of atmospheric processes (e.g., redox reactions and deposition) driving Hg cycling is still limited, especially in polar regions. The Antarctic continent, by virtue of its remoteness, is the perfect location to investigate Hg atmospheric processes in the absence of significant local anthropogenic impact. Here, we present the first 2 year record (2016-2017) of total suspended particulate mercury (PHg) concentrations along with a year-round determination of an Hg stable isotopic composition in particles collected at Zhongshan Station (ZSS), eastern Antarctic coast. The mean PHg concentration is 21.8 ± 32.1 pg/m3, ranging from 0.9 to 195.6 pg/m3, and peaks in spring and summer. The negative mass-independent fractionation of odd Hg isotopes (odd-MIF, average -0.38 ± 0.12‰ for Δ199Hg) and the slope of Δ199Hg/Δ201Hg with 0.91 ± 0.12 suggest that the springtime isotope variation of PHg is likely caused by in situ photo-oxidation and reduction reactions. On the other hand, the increase of PHg concentrations and the observed odd-MIF values in summer are attributed to the transport by katabatic winds of divalent species derived from the oxidation of elemental Hg in the inland Antarctic Plateau.
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Affiliation(s)
- Chuanjin Li
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
| | - Jiubin Chen
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Hélène Angot
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado 80309, United States
| | - Wang Zheng
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Guitao Shi
- Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences and State Key Lab of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
- Polar Research Institute of China, Shanghai 200062, China
| | - Minghu Ding
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
- Institute of Tibetan Plateau and Polar Regions Meteorology, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Zhiheng Du
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
| | - Qianggong Zhang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiangyu Ma
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
| | - Cunde Xiao
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
| | - Jiawen Ren
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
| | - Dahe Qin
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,China
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Lepak RF, Janssen SE, Engstrom DR, Krabbenhoft DP, Tate MT, Yin R, Fitzgerald WF, Nagorski SA, Hurley JP. Resolving Atmospheric Mercury Loading and Source Trends from Isotopic Records of Remote North American Lake Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9325-9333. [PMID: 32597170 PMCID: PMC7781044 DOI: 10.1021/acs.est.0c00579] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The strongest evidence for anthropogenic alterations to the global mercury (Hg) cycle comes from historical records of mercury deposition preserved in lake sediments. Hg isotopes have added a new dimension to these sedimentary archives, promising additional insights into Hg source apportionment and biogeochemical processing. Presently, most interpretations of historical changes are constrained to a small number of locally contaminated ecosystems. Here, we describe changes in natural Hg isotope records from a suite of dated sediment cores collected from various remote lakes of North America. In nearly all cases, the rise in industrial-use Hg is accompanied by an increase in δ202Hg and Δ199Hg values. These trends can be attributed to large-scale industrial emission of Hg into the atmosphere and are consistent with positive Δ199Hg values measured in modern-day precipitation and modeled increases in δ202Hg values from global emission inventories. Despite similar temporal trends among cores, the baseline isotopic values vary considerably among the different study regions, likely attributable to differences in the fractionation produced in situ as well as differing amounts of atmospherically delivered Hg. Differences among the study lakes in precipitation and watershed size provide an empirical framework for evaluating Hg isotopic signatures and global Hg cycling.
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Affiliation(s)
- Ryan F. Lepak
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Street, Madison, WI 53706, USA
- U.S. Geological Survey, Upper Midwest Water Science Center, USGS Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
- 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
- corresponding author: Ryan Lepak, U.S. EPA Office of Research and Development, Center for Computational Toxicology and Exposure, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA –
| | - Sarah E. Janssen
- U.S. Geological Survey, Upper Midwest Water Science Center, USGS Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - Daniel R. Engstrom
- St. Croix Watershed Research Station, Science Museum of Minnesota, 16910 152nd St. N., Marine on St. Croix, MN 55047, USA
| | - David P. Krabbenhoft
- U.S. Geological Survey, Upper Midwest Water Science Center, USGS Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - Michael T. Tate
- U.S. Geological Survey, Upper Midwest Water Science Center, USGS Mercury Research Laboratory, 8505 Research Way, Middleton, WI 53562, USA
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 99 Lincheng West Road, Guanshanhu District, Guiyang, Guizhou 550081, China
| | | | - Sonia A. Nagorski
- University of Alaska Southeast, Department of Natural Sciences, Juneau, AK 99801, USA
| | - James P. Hurley
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 N. Park Street, Madison, WI 53706, USA
- University of Wisconsin Aquatic Sciences Center, 1975 Willow Dr., Madison, WI 53706, USA
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Yuan W, Wang X, Lin CJ, Wu C, Zhang L, Wang B, Sommar J, Lu Z, Feng X. Stable Mercury Isotope Transition during Postdepositional Decomposition of Biomass in a Forest Ecosystem over Five Centuries. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8739-8749. [PMID: 32551609 DOI: 10.1021/acs.est.0c00950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Organic soil is an important transient reservoir of mercury (Hg) in terrestrial ecosystems, but the fate of deposited Hg in organic forest soil is poorly understood. To understand the dynamic changes of deposited Hg on forest floor, the composition of stable Hg and carbon (C) isotopes in decomposing litters and organic soil layer was measured to construct the 500 year history of postdepositional Hg transformation in a subtropical evergreen broad-leaf forest in Southwest China. Using the observational data and a multiprocess isotope model, the contributions of microbial reduction, photoreduction, and dark reduction mediated by organic matter to the isotopic transition were estimated. Microbial reduction and photoreduction play a dominant role in the initial litter decomposition during first 2 years. Dark redox reactions mediated by organic matter become the predominant process in the subsequent 420 years. After that, the values of Hg mass dependent fractionation (MDF), mass independent fractionation (MIF), and Δ199Hg/Δ201Hg ratio do not change significantly, indicating sequestration and immobilization of Hg in soil. The linear correlations between the isotopic signatures of Hg and C suggest that postdepositional transformation of Hg is closely linked to the fate of natural organic matter (NOM). Our findings are consistent with the abiotic dark reduction driven by nuclear volume effect reported in boreal and tropical forests. We recommend that the dark reduction process be incorporated in future model assessment of the global Hg biogeochemical cycle.
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Affiliation(s)
- Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
| | - Chuansheng Wu
- Anhui Province Key Laboratory of Environmental Hormone and Reproduction, Fuyang Normal University, Anhui 236037, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario M3H 5T4, Canada
| | - Bo Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Zhiyun Lu
- National Forest Ecosystem Research Station at Ailaoshan, Yunnan 676209, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
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49
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Tsui MTK, Blum JD, Kwon SY. Review of stable mercury isotopes in ecology and biogeochemistry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 716:135386. [PMID: 31839301 DOI: 10.1016/j.scitotenv.2019.135386] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/21/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Due to the advent of cold vapor-multicollector-inductively coupled plasma mass spectrometry (CV-MC-ICP-MS) in the past two decades, many research groups studying mercury (Hg) biogeochemistry have integrated stable Hg isotopes into their research. Currently, >200 studies using this technique have been published and this has greatly enhanced our understanding of the Hg biogeochemical cycle beyond what Hg concentration and speciation analyses alone can provide. These studies are largely divided into two groups: (i) controlled experiments investigating fractionation of Hg isotopes and refining tools of isotopic analyses, and (ii) studies of natural variations of Hg isotopes. It is now known that Hg isotopes undergo both mass dependent fractionation (MDF; reported as the ratio of mass 202Hg to 198Hg) and mass independent fractionation (MIF), with MIF occurring at odd masses (199Hg, 201Hg) to a larger magnitude and at even masses (200Hg, 204Hg) to a much smaller magnitude. The two types of MIF are controlled by different photochemical processes. The range of isotopic variations of MDF, odd-MIF, and even-MIF are now well documented in a diverse set of environmental samples, and researchers are continuing to explore how the field of Hg isotope biogeochemistry can be further developed and taken to the next level of understanding. One application that has received considerable attention is the use of Hg isotopes to examine the environmental controls on the production and degradation of methylmercury (MeHg), the most toxic and bioaccumulative form of Hg. Since MeHg is efficiently assimilated and biomagnified along food chains, MeHg has the potential to be a robust ecological tracer. In this review, we give an updated overview of the field of Hg isotopes and focus on how Hg isotopes of MeHg can be used to address fundamental ecological questions, including energy transfer across ecosystem interfaces and as a tracer for animal movements.
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Affiliation(s)
- Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sae Yun Kwon
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 37673, South Korea
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50
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Jiang T, Kaal J, Liu J, Liang J, Zhang Y, Wang D. Linking the electron donation capacity to the molecular composition of soil dissolved organic matter from the Three Gorges Reservoir areas, China. J Environ Sci (China) 2020; 90:146-156. [PMID: 32081311 DOI: 10.1016/j.jes.2019.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 11/11/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Soil dissolved organic matter (DOM) plays an essential role in the Three Gorges Reservoir (TGR) as a linkage between terrestrial and aquatic systems. In particular, the reducing capacities of soil DOM influence the geochemistry of contaminants such as mercury (Hg). However, few studies have investigated the molecular information of soil DOM and its relationship with relevant geochemical reactivities, including redox properties. We collected samples from eight sites in the TGR areas and studied the link between the molecular characteristics of DOM and their electron donation capacities (EDCs) toward Hg(II). The average kinetic rate and EDC of soil DOM in TGR areas were (0.004 ± 0.001) hr-1 and (2.88 ± 1.39) nmol e-/mg DOMbulk, respectively. Results suggest that higher EDCs and relatively rapid kinetics were related to the greater electron donating components of lignin-derived and perhaps pyrogenic DOM, which are the aromatic constituents that influenced the reducing capacities of DOM in the present study. Molecular details revealed that even the typical autochthonous markers are important for the EDCs of DOM as well, in contrast to what is generally assumed. More studies identifying specific DOM molecular components involved in the abiotic reduction of Hg(II) are required to further understand the relations between DOM sources and their redox roles in the environmental fate of contaminants.
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Affiliation(s)
- Tao Jiang
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, College of Resources and Environment, Southwest University, Chongqing 400716, China; Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Joeri Kaal
- Institut für Geoökologie, Abt. Umweltgeochemie, Technische Universität Braunschweig, Langer Kamp 19c, 38106, Braunschweig, Germany
| | - Jiang Liu
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, 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
| | - Jian Liang
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, College of Resources and Environment, Southwest University, Chongqing 400716, China; College of Chemistry and Environmental Engineering, Baise University, Guangxi, 533000, China
| | - Yaoling Zhang
- Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
| | - Dingyong Wang
- State Cultivation Base of Eco-agriculture for Southwest Mountainous Land, College of Resources and Environment, Southwest University, Chongqing 400716, China.
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