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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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Shi T, Zhan P, Shen Y, Wang H, Wu C, Li J. Using multi-technology to characterize transboundary Hg pollution in the largest presently active Hg deposit in China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-28080-0. [PMID: 37322398 DOI: 10.1007/s11356-023-28080-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 05/31/2023] [Indexed: 06/17/2023]
Abstract
Active Hg mines are primary sources of Hg contamination in the environment of mining districts and surrounding areas. Alleviation of Hg pollution requires knowledge of pollution sources, migration, and transform pathways across various environmental media. Accordingly, the Xunyang Hg-Sb mine, the largest active Hg deposit in China, presently was selected as the study area. GIS, TIMA, EPMA, μ-XRF, TEM-EDS, and Hg stable isotopes were adopted to investigate the spatial distribution, mineralogical characteristics, in situ microanalysis, and pollution sources of Hg in the environment medium at the macro- and micro-levels. The total Hg concentration in samples showed a regional distribution, with higher levels in areas close to the mining operations. The in situ distribution of Hg in soil was mainly associated with the mineralogical phases of quartz, and Hg was also correlated with Sb and S. Hg was also found to be rich mainly in quartz minerals in the sediment and showed different distributions of Sb. Hg hotspots had S abundances and contained no Sb and O. The contributions from the anthropogenic sources to soil Hg were estimated to be 55.35%, among which 45.97% from unroasted Hg ore and 9.38% from tailing. Natural input of soil Hg due to pedogenic processes accounted for 44.65%. Hg in corn grain was mainly derived from the atmosphere. This study will provide a scientific basis for assessing the current environmental quality in this area and minimizing further impacts that affect the nearby environmental medium.
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Affiliation(s)
- Taoran Shi
- School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
| | - Pei Zhan
- School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Yaqin Shen
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Hongyan Wang
- Beijing Dabeinong Technology Group Co., Ltd., Beijing, 100000, China
| | - Chunfa Wu
- School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Jining Li
- School of Environment, Nanjing Normal University, Nanjing, 210023, China
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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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5
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Jin X, Yan J, Ali MU, Li Q, Li P. Mercury Biogeochemical Cycle in Yanwuping Hg Mine and Source Apportionment by Hg Isotopes. TOXICS 2023; 11:toxics11050456. [PMID: 37235270 DOI: 10.3390/toxics11050456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023]
Abstract
Although mercury (Hg) mining activities in the Wanshan area have ceased, mine wastes remain the primary source of Hg pollution in the local environment. To prevent and control Hg pollution, it is crucial to estimate the contribution of Hg contamination from mine wastes. This study aimed to investigate Hg pollution in the mine wastes, river water, air, and paddy fields around the Yanwuping Mine and to quantify the pollution sources using the Hg isotopes approach. The Hg contamination at the study site was still severe, and the total Hg concentrations in the mine wastes ranged from 1.60 to 358 mg/kg. The binary mixing model showed that, concerning the relative contributions of the mine wastes to the river water, dissolved Hg and particulate Hg were 48.6% and 90.5%, respectively. The mine wastes directly contributed 89.3% to the river water Hg contamination, which was the main Hg pollution source in the surface water. The ternary mixing model showed that the contribution was highest from the river water to paddy soil and that the mean contribution was 46.3%. In addition to mine wastes, paddy soil is also impacted by domestic sources, with a boundary of 5.5 km to the river source. This study demonstrated that Hg isotopes can be used as an effective tool for tracing environmental Hg contamination in typical Hg-polluted areas.
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Affiliation(s)
- Xingang Jin
- Key Laboratory for Information System of Mountainous Area and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guiyang 550001, China
| | - Junyao Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Muhammad Ubaid Ali
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Qiuhua Li
- Key Laboratory for Information System of Mountainous Area and Protection of Ecological Environment of Guizhou Province, Guizhou Normal University, Guiyang 550001, China
| | - Ping Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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Sun R, Cao F, Dai S, Shan B, Qi C, Xu Z, Li P, Liu Y, Zheng W, Chen J. Atmospheric Mercury Isotope Shifts in Response to Mercury Emissions from Underground Coal Fires. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37167064 DOI: 10.1021/acs.est.2c08637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Pollutant emissions from coal fires have caused serious concerns in major coal-producing countries. Great efforts have been devoted to suppressing them in China, notably at the notorious Wuda Coalfield in Inner Mongolia. Recent surveys revealed that while fires in this coalfield have been nearly extinguished near the surface, they persist underground. However, the impacts of Hg volatilized from underground coal fires remain unclear. Here, we measured concentrations and isotope compositions of atmospheric Hg in both gaseous and particulate phases at an urban site near the Wuda Coalfield. The atmospheric Hg displayed strong seasonality in terms of both Hg concentrations (5-7-fold higher in fall than in winter) and isotope compositions. Combining characteristic isotope compositions of potential Hg sources and air mass trajectories, we conclude that underground coal fires were still emitting large amounts of Hg into the atmosphere that have been transported to the adjacent urban area in the prevailing downwind direction. The other local anthropogenic Hg emissions were only evident in the urban atmosphere when the arriving air masses did not pass directly through the coalfield. Our study demonstrates that atmospheric Hg isotope measurement is a useful tool for detecting concealed underground coal fires.
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Affiliation(s)
- Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Fei Cao
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Shifeng Dai
- College of Geoscience and Survey Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Bing Shan
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Cuicui Qi
- Anhui Academy of Eco-environmental Science Research, Hefei 230071, China
| | - Zhanjie Xu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Pengfei Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Yi Liu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Wang Zheng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Jiubin Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
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7
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Crowther ER, Demers JD, Blum JD, Brooks SC, Johnson MW. Coupling of nitric acid digestion and anion-exchange resin separation for the determination of methylmercury isotopic composition within organisms. Anal Bioanal Chem 2023; 415:759-774. [PMID: 36472636 DOI: 10.1007/s00216-022-04468-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/19/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
Isotope ratios of methylmercury (MeHg) within organisms can be used to identify sources of MeHg that have accumulated in food webs, but these isotopic compositions are masked in organisms at lower trophic levels by the presence of inorganic mercury (iHg). To facilitate measurement of MeHg isotope ratios in organisms, we developed a method of extracting and isolating MeHg from fish and aquatic invertebrates for compound-specific isotopic analysis involving nitric acid digestion, batch anion-exchange resin separation, and pre-concentration by purge and trap. Recovery of MeHg was quantified after each step in the procedure, and the average cumulative recovery of MeHg was 93.4 ± 2.9% (1 SD, n = 28) for biological reference materials and natural biota samples and 96.9 ± 1.8% (1 SD, n = 5) for aqueous MeHgCl standards. The amount of iHg impurities was also quantified after each step, and the average MeHg purity was 97.8 ± 4.3% (1 SD, n = 28) across all reference materials and natural biota samples after the final separation step. Measured MeHg isotopic compositions of reference materials agreed with literature values obtained using other MeHg separation techniques, and MeHg isotope ratios of aqueous standards, reference materials, and natural biota samples were reproducible. On average, the reproducibility associated with reference material process replicates (2 SD) was 0.10‰ for δ202MeHg and 0.04‰ for Δ199MeHg. This new method provides a streamlined, reliable technique that utilizes a single sample aliquot for MeHg concentration and isotopic analysis. This promotes a tight coupling between MeHg concentration, %MeHg, and Hg isotopic composition, which may be especially beneficial for studying complex food webs with multiple isotopically distinct sources of iHg and/or MeHg.
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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
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Rd., Durham, NH, 03824-2600, 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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Wang J, Man Y, Yin R, Feng X. Isotopic and Spectroscopic Investigation of Mercury Accumulation in Houttuynia cordata Colonizing Historically Contaminated Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7997-8007. [PMID: 35618674 DOI: 10.1021/acs.est.2c00909] [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
Houttuynia cordata Thunb (H. cordata) is a native vegetable colonizing mercury (Hg) mining sites in the southwest of China; it can accumulate high Hg concentrations in the rhizomes and roots (edible sections), and thus consumption of H. cordata represents an important Hg exposure source to human. Here, we studied the spatial distribution, chemical speciation, and stable isotope compositions of Hg in the soil-H. cordata system at the Wuchuan Hg mining region in China, aiming to provide essential knowledge for assessing Hg risks and managing the transfer of Hg from soils to plants and agricultural systems. Mercury was mainly compartmentalized in the outlayer (periderm) of the underground tissues, with little Hg being translocated to the vascular bundle of the stem. Mercury presented as Hg-thiolates (94% ± 8%), with minor fractional amount of nanoparticulate β-HgS (β-HgSNP, 15% ± 4%), in the roots and rhizomes. Analysis of Hg stable isotope ratios showed that cysteine-extractable soil Hg pool (δ202Hgcys), root and rhizome Hg (δ202Hgroot, δ202Hgrhizome) were isotopically lighter than Hg in the bulk soils. A significant positive correlation between δ202Hgcys and δ202Hgroot was observed, suggesting that cysteine-extractable soil Hg pool was an important Hg source to H. cordata. The slightly positive Δ199Hg value in the plant (Δ199Hgroot = 0.07 ± 0.07‰, 2SD, n = 21; Δ199Hgrhizome = 0.06 ± 0.06‰, 2SD, n = 22) indicated that minor Hg was sourced from the surface water. Our results are important to assess the risks of Hg in H. cordata, and to develop sustainable methods to manage the transfer of Hg from soils to agricultural systems.
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Affiliation(s)
- Jianxu Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550082, China
| | - Yi Man
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550082, China
| | - Runsheng Yin
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550082, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550082, China
- CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China
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Sun R, Hintelmann H, Wiklund JA, Evans MS, Muir D, Kirk JL. Mercury Isotope Variations in Lake Sediment Cores in Response to Direct Mercury Emissions from Non-Ferrous Metal Smelters and Legacy Mercury Remobilization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8266-8277. [PMID: 35616385 DOI: 10.1021/acs.est.2c02692] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nature archives record atmospheric mercury (Hg) depositions from directly emitted Hg and re-emitted legacy Hg. Tracing the legacy versus newly deposited Hg is still, however, challenging. Here, we measured Hg isotope compositions in three dated sediment cores at different distances from the Flin Flon smelter, the largest Canadian Hg sources to the atmosphere during the 1930s-2000s. During the smelter's operative period, Hg isotope compositions showed limited variations in the near-field lake (<10 km) sediments but were rather variable in middle- (20-75 km) and far-field lake (∼800 km) sediments. Only the post-2000 sediments in middle/far-field lakes showed significantly negative Hg isotope shifts, while sediments from the 1970s-1990s had Hg isotope values resembling those of near-field lake post-1930 sediments. We suggest that the smelter's peak Hg emissions during the 1970s-1990s, which coincided with the deployment of a super stack in the mid-1970s, largely increased the long-range dispersion of smelter plumes. For the top post-2000 sediments, the fugitive dust from ore tailings and terrestrial legacy Hg re-emissions dominated Hg deposition in near-field lakes and middle/far-field lakes, respectively. Our study demonstrates that legacy Hg remobilization now exports substantial amounts of Hg to ecosystems, highlighting the need for aggressive remediation measures of Hg-contaminated sites.
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Affiliation(s)
- Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
- Water Quality Centre, Trent University, Peterborough, Ontario K9J 7B8, Canada
| | - Holger Hintelmann
- Water Quality Centre, Trent University, Peterborough, Ontario K9J 7B8, Canada
| | - Johan A Wiklund
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, Burlington, Ontario L7R 4A6, Canada
| | - Marlene S Evans
- Watershed Hydrology and Ecology Research Division, Environment and Climate Change Canada, Saskatoon, Saskatchewan S7N 3H5, Canada
| | - Derek Muir
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, Burlington, Ontario L7R 4A6, Canada
| | - Jane L Kirk
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, Burlington, Ontario L7R 4A6, Canada
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10
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Irei S. Stable Isotope Ratios of Mercury in Commercially Available Thermometers and Fluorescent Tubes. ACS OMEGA 2022; 7:9291-9302. [PMID: 35350359 PMCID: PMC8945125 DOI: 10.1021/acsomega.1c06060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/25/2022] [Indexed: 05/28/2023]
Abstract
Five stable isotope ratios of mercury (199Hg/198Hg, 200Hg/198Hg, 201Hg/198Hg, 202Hg/198Hg, and 204Hg/198Hg) in commercially available thermometers and fluorescent tubes were analyzed to characterize their potential anthropogenic emission source to landfills, manufacturing factories, and our daily lives. The results for the liquid metal mercury yielded from the thermometers showed similar mass-independent fractionation values to those in the literature. The analysis of fluorescent tubes resulted in that more than 96% of mercury in the fluorescent tubes was found in the adsorbed state, and up to 3.5% of mercury was in the gas-phase. Unique mass-independent isotope fractionation values were found in the gaseous and adsorbed mercury in the fluorescent tubes. This fractionation is distinct from other emission sources and systematic; therefore, it can potentially be used to fingerprint mercury in fluorescent tubes in environmental samples.
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11
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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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12
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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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Wang L, Jin Y, Weiss DJ, Schleicher NJ, Wilcke W, Wu L, Guo Q, Chen J, O'Connor D, Hou D. Possible application of stable isotope compositions for the identification of metal sources in soil. JOURNAL OF HAZARDOUS MATERIALS 2021; 407:124812. [PMID: 33340973 DOI: 10.1016/j.jhazmat.2020.124812] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/22/2020] [Accepted: 12/05/2020] [Indexed: 06/12/2023]
Abstract
Metals in soil are potentially harmful to humans and ecosystems. Stable isotope measurement may provide "fingerprint" information on the sources of metals. In light of the rapid progress in this emerging field, we present a state-of-the-art overview of how useful stable isotopes are in soil metal source identification. Distinct isotope signals in different sources are the key prerequisites for source apportionment. In this context, Zn and Cd isotopes are particularly helpful for the identification of combustion-related industrial sources, since high-temperature evaporation-condensation would largely fractionate the isotopes of both elements. The mass-independent fractionation of Hg isotopes during photochemical reactions allows for the identification of atmospheric sources. However, compared with traditionally used Sr and Pb isotopes for source tracking whose variations are due to the radiogenic processes, the biogeochemical low-temperature fractionation of Cr, Cu, Zn, Cd, Hg and Tl isotopes renders much uncertainty, since large intra-source variations may overlap the distinct signatures of inter-source variations (i.e., blur the source signals). Stable isotope signatures of non-metallic elements can also aid in source identification in an indirect way. In fact, the soils are often contaminated with different elements. In this case, a combination of stable isotope analysis with mineralogical or statistical approaches would provide more accurate results. Furthermore, isotope-based source identification will also be helpful for comprehending the temporal changes of metal accumulation in soil systems.
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Affiliation(s)
- Liuwei Wang
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Yuanliang Jin
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Dominik J Weiss
- Department of Earth Science & Engineering, Imperial College London, London SW7 2AZ, United Kingdom; Civil and Environmental Engineering, Princeton University, New York, USA
| | - Nina J Schleicher
- Department of Earth Science & Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Wolfgang Wilcke
- Institute of Geography and Geoecology, Karlsruhe Institute of Technology (KIT), Reinhard-Baumeister-Platz 1, Karlsruhe 76131, Germany
| | - Longhua Wu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Qingjun Guo
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiubin Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - David O'Connor
- School of Real Estate and Land Management, Royal Agricultural University, Cirencester, GL7 1RS, United Kingdom
| | - Deyi Hou
- School of Environment, Tsinghua University, Beijing 100084, China.
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Li Z, Chen X, Liu W, Li T, Qiu G, Yan H, Wang M, Chen J, Sun G, Wang Q, Feng X. Soil and ambient air mercury as an indicator of coal-fired power plant emissions: a case study in North China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:10.1007/s11356-021-12842-9. [PMID: 33635465 DOI: 10.1007/s11356-021-12842-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Coal-fired power plants (CFPPs) are an important anthropogenic mercury (Hg) source in China, and it is crucial to understand the environmental impacts of this detrimental element emitted from this source. In the present study, field experiments were conducted for measuring Hg in ambient atmosphere and upland agricultural soils within a radius of 10 km surrounding a large scale coal-fired power plant (1550 MW) in Tangshan, Hebei province. Short-term (20 min) average of gaseous elemental mercury (GEM or Hg0) in ambient air varying from 1.5 to 9.0 ng/m3 and total Hg (THg) in surface agricultural soil (0-20 cm) varying from 9.2 to 43.5 μg/kg at different sites were observed. THg in two soil cores decreased with depth, with concentrations being 2-2.5 times higher in the surface layer than that in the deep layer (50-60 cm), indicating the possibility of the atmospheric input of Hg. Based on the information of the total atmospheric Hg emission since this CFPP's operation in 1970s and the increased THg in nearby soils, it was estimated that about 3.9% discharged Hg has accumulated in the nearby agricultural soils. The low retention rate of the total emitted Hg by soils is a result of high proportion of Hg0 (79.5%) in stack gas emission and potential loss of Hg from soil surface reemission. The positive shifting (~ 0.5‰) of Hg isotopic signature (δ202Hg) from deep soil to surface soil reflected Hg deposition from nearby CFPP emissions that are featured with much heavier Hg isotopic signatures inherited from feed coal (δ202Hg: -0.50‰) and different combustion products (δ202Hg: -0.95 to 3.71‰) compared with that in deep soil layer (δ202Hg: ca -1.50‰). Overall, this study demonstrated that this CFPP has a slight but distinguishable effect on the elevation of ambient GEM and agricultural soil THg in the local environment.
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Affiliation(s)
- Zhonggen Li
- School of Resources and Environment, Zunyi Normal College, Zunyi, 563006, China.
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Xufeng Chen
- Tangshan Environmental Monitoring Center of Hebei Province, Tangshan, 063000, China
| | - Wenli Liu
- Tangshan Environmental Monitoring Center of Hebei Province, Tangshan, 063000, China
| | - Taishan Li
- Tangshan Institute of Environmental Protection, Tangshan, 063000, China
| | - Guangle Qiu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Haiyu Yan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Mingmeng Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Ji Chen
- 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
| | - Qingfeng Wang
- School of Resources and Environment, Zunyi Normal College, Zunyi, 563006, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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Li X, Chen J, Tang L, Wu T, Fu C, Li Z, Sun G, Zhao H, Zhang L, Li Q, Feng X. Mercury isotope signatures of a pre-calciner cement plant in Southwest China. JOURNAL OF HAZARDOUS MATERIALS 2021; 401:123384. [PMID: 32763687 DOI: 10.1016/j.jhazmat.2020.123384] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 06/29/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Characterizing the composition of mercury (Hg) isotopes in the atmospheric emissions of cement plants is critical to understand the global circulation of Hg because large quantities of Hg are released from this source annually. A pre-calciner cement plant in Guizhou Province in Southwest China was selected to investigate the mass dependent fractionation (MDF) and mass independent fractionation (MIF) of Hg in the entire production process and the speciated Hg isotope composition in stack gas. Significant MDF and insignificant MIF were observed in this cement plant. Different raw/correction materials have δ202Hg signals ranging from -1.68 to -2.19‰. Raw meal is featured with lighter Hg (δ202Hg = -2.83 ± 0.18‰) as results of Hg circulation and accumulation during the clinker production. Cement products possess negative δ202Hg values (-1.98 ± 0.02‰) due to the input of light δ202Hg isotopes through additives/retarder limestone, and fly ash and gypsum from coal-fired power plant (CFPPs). Speciated Hg isotopes in the stack gas of the kiln tail and kiln head show no significant differences, and δ202Hg and Δ199Hg in the discharged flue gas averaged at -2.03 ± 0. 31‰ and -0.03 ± 0.07‰, respectively, which has negative δ202Hg characteristics with other anthropogenic sources.
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Affiliation(s)
- Xinyu 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
| | - Ji Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Guizhou Provincial Laboratory for Mountainous Environment, Guizhou Normal University, Guiyang, 550001, China
| | - Li Tang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; College of Resource and Environmental Engineering, Guizhou University, Guiyang, 550025, China
| | - Tingting Wu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang, 550003, China
| | - Chengcheng Fu
- Guizhou Environmental Monitoring Center, Guiyang, 550081, China
| | - Zhonggen Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; College of Resources and Environment, Zunyi Normal University, Zunyi, 563006, China.
| | - Guangyi Sun
- 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
| | - Huifang Zhao
- 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, Canada
| | - Qiuhua Li
- Guizhou Provincial Laboratory for Mountainous Environment, Guizhou Normal University, Guiyang, 550001, 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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Yuan J, Sun R, Wang R, Fu B, Meng M, Zheng W, Chen J. Denitrification devices in urban boilers change mercury isotope fractionation signatures of coal combustion products. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115753. [PMID: 33045583 DOI: 10.1016/j.envpol.2020.115753] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 09/13/2020] [Accepted: 09/27/2020] [Indexed: 06/11/2023]
Abstract
The installation rate of denitrification devices is accelerating in Chinese urban boilers. Previous studies on pulverized coal-fired boilers without denitrification devices showed that combustion products containing mainly oxidized mercury (Hg) preferably enriched lighter Hg isotopes than feed coals. However, the magnitude of this enrichment becomes less pronounced if denitrification devices are installed. The underlying Hg isotope fractionation mechanisms are still unclear. In this study, three types of urban boilers (two pulverized coal-fired boilers, one circulating fluidized bed boiler and one municipal waste incinerator boiler) all installed with denitrification devices were measured for Hg isotope compositions of their feed fuels and corresponding combustion products. We observed little mass independent fractionation but very significant mass dependent fractionation (MDF) between feed fuels and combustion products. The fly ash and desulfurization products both enriched heavier Hg isotopes than feed coals in three coal-fired boilers, and the enrichment of heavy Hg isotopes increased with sequential removal of combustion products in all boilers. Different from previously suggested kinetic MDF for gaseous Hg0(g)→HgII(g) and gaseous HgII(g)→particulate HgII(p) in coal combustion flue gases, we propose an equilibrium MDF for Hg0(g)↔HgII(g) followed by a kinetic MDF for HgII(g)→HgII(p). This equilibrium MDF most likely occurs during Hg0(g) oxidation in denitrification devices, which enriches heavy Hg isotopes in oxidized products (HgII(g) and HgII(p)) that are then sequestrated in fly ash and desulfurization products. The paradigm shift of MDF in boilers with denitrification devices was further verified by parallel Hg isotope measurement in urban atmosphere particulates. Our study clearly demonstrates that modern coal-fired boilers with denitrification devices have a quite different MDF compared to traditional boilers without denitrification devices. This has important implications for estimating isotope signatures of urban boiler Hg emissions, and for isotope tracing of anthropogenic Hg emissions.
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Affiliation(s)
- Jingjing Yuan
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Ruoyu Sun
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China.
| | - Ruwei Wang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China
| | - Biao Fu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Mei Meng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Wang Zheng
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Jiubin Chen
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, 300072, China
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17
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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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Sommar J, Osterwalder S, Zhu W. Recent advances in understanding and measurement of Hg in the environment: Surface-atmosphere exchange of gaseous elemental mercury (Hg 0). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 721:137648. [PMID: 32182462 DOI: 10.1016/j.scitotenv.2020.137648] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 05/26/2023]
Abstract
The atmosphere is the major transport pathway for distribution of mercury (Hg) globally. Gaseous elemental mercury (GEM, hereafter Hg0) is the predominant form in both anthropogenic and natural emissions. Evaluation of the efficacy of reductions in emissions set by the UN's Minamata Convention (UN-MC) is critically dependent on the knowledge of the dynamics of the global Hg cycle. Of these dynamics including e.g. red-ox reactions, methylation-demethylation and dry-wet deposition, poorly constrained atmosphere-surface Hg0 fluxes especially limit predictability of the timescales of its global biogeochemical cycle. This review focuses on Hg0 flux field observational studies, namely the theory, applications, strengths, and limitations of the various experimental methodologies applied to gauge the exchange flux and decipher active sub-processes. We present an in-depth review, a comprehensive literature synthesis, and methodological and instrumentation advances for terrestrial and marine Hg0 flux studies in recent years. In particular, we outline the theory of a wide range of measurement techniques and detail the operational protocols. Today, the most frequently used measurement techniques to determine the net Hg0 flux (>95% of the published flux data) are dynamic flux chambers for small-scale and micrometeorological approaches for large-scale measurements. Furthermore, top-down approaches based on Hg0 concentration measurements have been applied as tools to better constrain Hg emissions as an independent way to e.g. challenge emission inventories. This review is an up-dated, thoroughly revised edition of Sommar et al. 2013 (DOI: 10.1080/10643389.2012.671733). To the tabulation of >100 cited flux studies 1988-2009 given in the former publication, we have here listed corresponding studies published during the last decade with a few exceptions (2008-2019). During that decade, Hg stable isotope ratios of samples involved in atmosphere-terrestrial interaction is at hand and provide in combination with concentration and/or flux measurements novel constraints to quantitatively and qualitatively assess the bi-directional Hg0 flux. Recent efforts in the development of relaxed eddy accumulation and eddy covariance Hg0 flux methods bear the potential to facilitate long-term, ecosystem-scale flux measurements to reduce the prevailing large uncertainties in Hg0 flux estimates. Standardization of methods for Hg0 flux measurements is crucial to investigate how land-use change and how climate warming impact ecosystem-specific Hg0 sink-source characteristics and to validate frequently applied model parameterizations describing the regional and global scale Hg cycle.
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Affiliation(s)
- Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
| | - Stefan Osterwalder
- Institut des Géosciences de l'Environnement, Université Grenoble Alpes, CNRS, IRD, Grenoble INP, Grenoble, France
| | - Wei Zhu
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
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Yamakawa A, Bérail S, Amouroux D, Tessier E, Barre J, Sano T, Nagano K, Kanwal S, Yoshinaga J, Donard OFX. Hg isotopic composition and total Hg mass fraction in NIES Certified Reference Material No. 28 Urban Aerosols. Anal Bioanal Chem 2020; 412:4483-4493. [PMID: 32424796 PMCID: PMC7329778 DOI: 10.1007/s00216-020-02691-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/24/2020] [Accepted: 04/30/2020] [Indexed: 11/29/2022]
Abstract
An interlaboratory study on the National Institute for Environmental Studies (NIES) certified reference material (CRM) No. 28 Urban Aerosols, collected on the filters of a central ventilating system in a building in Beijing city center, was performed to obtain informative values of Hg isotopic composition and total Hg (THg) mass fraction. The THg mass fraction was determined by four organizations using atomic absorption spectrometry; it resulted in the mean value of 1.19 ± 0.12 mg/kg (2SD, n = 24). The Hg isotopic composition of the CRM was measured and intercompared at two different institutions by cold vapor generation system coupled to multicollector inductively coupled plasma mass spectrometry. Subsequently, a conventional dissolution method that uses a mixture of HNO3/HCl/H2O2 in Hotblock® and two different dissolution methods that use a mixture of HNO3/HCl with a microwave and a digestion bomb were applied. The Hg isotopic compositions were δ202Hg = − 1.26 ± 0.17‰, Δ199Hg = − 0.23 ± 0.06‰, Δ200Hg = 0.01 ± 0.07‰, and Δ201Hg = − 0.22 ± 0.09‰ (2SD, n = 18) for the conventional method, which agree well with those obtained using microwave and bomb digestion. Our results indicate that, for the quality control of particulate matter analyses, this CRM is appropriate for use in environmental and geochemical studies. Graphical abstract ![]()
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Affiliation(s)
- Akane Yamakawa
- Center for Environmental Measurement and Analysis, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
| | - Sylvain Bérail
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, 2 Avenue Pierre Angot, 64053, Pau Cedex 09, France
| | - David Amouroux
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, 2 Avenue Pierre Angot, 64053, Pau Cedex 09, France
| | - Emmanuel Tessier
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, 2 Avenue Pierre Angot, 64053, Pau Cedex 09, France
| | - Julien Barre
- Advanced Isotopic Analysis, Technopole Hélioparc Pau Pyrénées, 2 Avenue Pierre Angot, 64053, Pau Cedex 09, France
| | - Tomoharu Sano
- Center for Environmental Measurement and Analysis, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Kimiyo Nagano
- Center for Environmental Measurement and Analysis, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Sadia Kanwal
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8563, Japan
| | - Jun Yoshinaga
- Center for Environmental Measurement and Analysis, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
- Faculty of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura, Oura, Gunma, 394-0193, Japan
| | - Olivier F X Donard
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physicochimie pour l'Environnement et les Matériaux, 2 Avenue Pierre Angot, 64053, Pau Cedex 09, France
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Tuhý M, Rohovec J, Matoušková Š, Mihaljevič M, Kříbek B, Vaněk A, Mapani B, Göttlicher J, Steininger R, Majzlan J, Ettler V. The potential wildfire effects on mercury remobilization from topsoils and biomass in a smelter-polluted semi-arid area. CHEMOSPHERE 2020; 247:125972. [PMID: 32069734 DOI: 10.1016/j.chemosphere.2020.125972] [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: 08/26/2019] [Revised: 01/06/2020] [Accepted: 01/18/2020] [Indexed: 06/10/2023]
Abstract
Wildfires can be responsible for significant mercury (Hg) emissions especially in contaminated areas. Here, we investigated the Hg distribution in topsoils and vegetation samples and temperature-dependent Hg mobilization from biomass-rich topsoils collected near a copper (Cu) smelter in Tsumeb (semi-arid Namibia), where Hg-rich Cu concentrates are processed. The thermo-desorption (TD) experiments conducted on representative biomass-rich topsoils (3.9-7.7 mg Hg/kg) indicated that more than 91% of the Hg was released at ∼340 °C, which corresponds to the predominant grassland-fire conditions. The mineralogical investigation indicated that the Hg comes mainly from the deposited smelter emissions because no distinct Hg-rich microparticles corresponding to the windblown dust from the nearby disposal sites of the technological materials (concentrates, slags, tailings) were found. A comparison with the TD curves of the Hg reference compounds confirmed that the Hg in the biomass-rich topsoils occurs as a mixture of Hg bound to the organic matter and metacinnabar (black HgS), which exhibits similarities with the TD pattern of smelter flue dust residue. Despite the installation of a sulfuric acid plant in the smelter in 2015 and a calculated drop in the estimated Hg emissions (from 1301 ± 457 kg/y for the period 2004-2015 to 67 ± 5 kg/y after 2015), the Hg legacy pool in the smelter surroundings can potentially be re-emitted back to the atmosphere by wildfire. Using the Hg spatial distribution data in the area (184 km2), the estimates indicate that up to 303 kg and 1.3 kg can be remobilized from the topsoils and vegetation, respectively.
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Affiliation(s)
- Marek Tuhý
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00, Prague 2, Czech Republic.
| | - Jan Rohovec
- Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Šárka Matoušková
- Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 269, 165 00, Prague 6, Czech Republic
| | - Martin Mihaljevič
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00, Prague 2, Czech Republic
| | - Bohdan Kříbek
- Czech Geological Survey, Geologická 6, 152 00, Prague 5, 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 21, Prague 6, Czech Republic
| | - Ben Mapani
- Department of Geology, Faculty of Science, University of Namibia, Private Bag, 13301, Windhoek, Namibia
| | - Jörg Göttlicher
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, DE-76344, Eggenstein-Leopoldshafen, Germany
| | - Ralph Steininger
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, DE-76344, Eggenstein-Leopoldshafen, Germany
| | - Juraj Majzlan
- Institute of Geosciences, Friedrich-Schiller University, Burgweg 11, D-07749, Jena, Germany
| | - Vojtěch Ettler
- Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, 128 00, Prague 2, Czech Republic.
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21
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Eckley CS, Gilmour CC, Janssen S, Luxton TP, Randall PM, Whalin L, Austin C. The assessment and remediation of mercury contaminated sites: A review of current approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136031. [PMID: 31869604 PMCID: PMC6980986 DOI: 10.1016/j.scitotenv.2019.136031] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/07/2019] [Accepted: 12/07/2019] [Indexed: 04/13/2023]
Abstract
Remediation of mercury (Hg) contaminated sites has long relied on traditional approaches, such as removal and containment/capping. Here we review contemporary practices in the assessment and remediation of industrial-scale Hg contaminated sites and discuss recent advances. Significant improvements have been made in site assessment, including the use of XRF to rapidly identify the spatial extent of contamination, Hg stable isotope fractionation to identify sources and transformation processes, and solid-phase characterization (XAFS) to evaluate Hg forms. The understanding of Hg bioavailability for methylation has been improved by methods such as sequential chemical extractions and porewater measurements, including the use of diffuse gradient in thin-film (DGT) samplers. These approaches have shown varying success in identifying bioavailable Hg fractions and further study and field applications are needed. The downstream accumulation of methylmercury (MeHg) in biota is a concern at many contaminated sites. Identifying the variables limiting/controlling MeHg production-such as bioavailable inorganic Hg, organic carbon, and/or terminal electron acceptors (e.g. sulfate, iron) is critical. Mercury can be released from contaminated sites to the air and water, both of which are influenced by meteorological and hydrological conditions. Mercury mobilized from contaminated sites is predominantly bound to particles, highly correlated with total sediment solids (TSS), and elevated during stormflow. Remediation techniques to address Hg contamination can include the removal or containment of Hg contaminated materials, the application of amendments to reduce mobility and bioavailability, landscape/waterbody manipulations to reduce MeHg production, and food web manipulations through stocking or extirpation to reduce MeHg accumulated in desired species. These approaches often rely on knowledge of the Hg forms/speciation at the site, and utilize physical, chemical, thermal and biological methods to achieve remediation goals. Overall, the complexity of Hg cycling allows many different opportunities to reduce/mitigate impacts, which creates flexibility in determining suitable and logistically feasible remedies.
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Affiliation(s)
- Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101, USA.
| | - Cynthia C Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 21037-0028, USA.
| | - Sarah Janssen
- USGS Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA.
| | - Todd P Luxton
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Paul M Randall
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
| | - Lindsay Whalin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
| | - Carrie Austin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
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22
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Schudel G, Kaplan R, Adler Miserendino R, Veiga MM, Velasquez-López PC, Guimarães JRD, Bergquist BA. Mercury isotopic signatures of tailings from artisanal and small-scale gold mining (ASGM) in southwestern Ecuador. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 686:301-310. [PMID: 31181517 DOI: 10.1016/j.scitotenv.2019.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/01/2019] [Accepted: 06/01/2019] [Indexed: 06/09/2023]
Abstract
Artisanal and small-scale gold mining (ASGM) is currently one of the largest anthropogenic sources of mercury (Hg) to the atmosphere and a significant source to downstream terrestrial aquatic systems. Given the potential toxicity of Hg when it is released to aquatic ecosystems, both scientific and regulatory communities have interest in the development of tools and methods for understanding the fate and transport of Hg in the environment. Although Hg isotopes are applied extensively to trace other anthropogenic point sources of Hg in aquatic ecosystems, few studies have used isotopic analyses to investigate the downstream impacts of ASGM. Furthermore, these studies are currently limited by relatively sparse Hg isotopic analyses on ASGM materials. In this study, ASGM samples from Portovelo-Zaruma (Ecuador), representing various stages of the processing of low-grade gold-bearing ores, were analyzed for Hg concentrations and stable isotope ratios. These data were used to assess the isotopic variability of the ASGM endmember and confirm the results of prior isotopic analyses of ASGM materials and downstream sediments from Portovelo-Zaruma. While the Hg concentrations of the ASGM samples varied significantly, isotopic analyses revealed a limited range of signatures that was characterized by relatively heavy mass-dependent fractionation (MDF) with little to no significant mass-independent fractionation (MIF). The signatures of ASGM samples analyzed in this study matched well with previously reported ASGM samples from Portovelo-Zaruma as well as downstream sediments (for up to 120 km). Furthermore, the overall Hg isotopic compositions of potential ASGM endmembers are distinct from typical compositions observed in freshwater ecosystems (e.g., from soil erosion, atmospheric deposition), allowing Hg isotopes to be a powerful tool in tracing downstream Hg contamination from ASGM.
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Affiliation(s)
- Gary Schudel
- University of Toronto, Department of Earth Sciences, 22 Russell Street, Toronto M5S 3B1, ON, Canada
| | - Robert Kaplan
- University of Toronto, Department of Earth Sciences, 22 Russell Street, Toronto M5S 3B1, ON, Canada
| | - Rebecca Adler Miserendino
- University of Toronto, Department of Earth Sciences, 22 Russell Street, Toronto M5S 3B1, ON, Canada; Johns Hopkins University Bloomberg School of Public Health, Department of Environmental Health Sciences, 615 N. Wolfe Street, Baltimore 21205-2103, MD, USA
| | - Marcello M Veiga
- University of British Columbia, Norman B. Keevil Institute of Mining Engineering, Vancouver, BC V6T IZ4, Canada
| | - P Colon Velasquez-López
- Universidad Tecnica de Machala, Avenida Paquisha Km 5,5 via Pasaje-Machala, Machala, El Oro, Ecuador
| | - Jean Remy Davée Guimarães
- Universidade Federal do Rio de Janeiro, Inst. de Biofísica Carlos Chagas Filho, Bloco G, CCS, Ilha do Fundão, Rio de Janeiro 21949-902, Brazil
| | - Bridget A Bergquist
- University of Toronto, Department of Earth Sciences, 22 Russell Street, Toronto M5S 3B1, ON, Canada.
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23
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Janssen SE, Riva-Murray K, DeWild JF, Ogorek JM, Tate MT, Van Metre PC, Krabbenhoft DP, Coles JF. Chemical and Physical Controls on Mercury Source Signatures in Stream Fish from the Northeastern United States. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10110-10119. [PMID: 31390861 DOI: 10.1021/acs.est.9b03394] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Streams in the northeastern U.S. receive mercury (Hg) in varying proportions from atmospheric deposition and legacy point sources, making it difficult to attribute shifts in fish concentrations directly back to changes in Hg source management. Mercury stable isotope tracers were utilized to relate sources of Hg to co-located fish and bed sediments from 23 streams across a forested to urban-industrial land-use gradient within this region. Mass-dependent isotopes (δ202Hg) in prey and game fish at forested sites were depleted (medians -0.95 and -0.83 ‰, respectively) in comparison to fish from urban-industrial settings (medians -0.26 and -0.38 ‰, respectively); the forested site group also had higher prey fish Hg concentrations. The separation of Hg isotope signatures in fish was strongly related to in-stream and watershed land-use indicator variables. Fish isotopes were strongly correlated with bed sediment isotopes, but the isotopic offset between the two matrices was variable due to differing ecosystem-specific drivers controlling the extent of MeHg formation. The multivariable approach of analyzing watershed characteristics and stream chemistry reveals that the Hg isotope composition in fish is linked to current and historic Hg sources in the northeastern U.S. and can be used to trace bioaccumulated Hg.
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Affiliation(s)
- Sarah E Janssen
- United States Geological Survey, Upper Midwest Water Science Center , Middleton , Wisconsin 53562 , United States
| | - Karen Riva-Murray
- United States Geological Survey, New York Water Science Center , Troy , New York 12180 , United States
| | - John F DeWild
- United States Geological Survey, Upper Midwest Water Science Center , Middleton , Wisconsin 53562 , United States
| | - Jacob M Ogorek
- United States Geological Survey, Upper Midwest Water Science Center , Middleton , Wisconsin 53562 , United States
| | - Michael T Tate
- United States Geological Survey, Upper Midwest Water Science Center , Middleton , Wisconsin 53562 , United States
| | - Peter C Van Metre
- United States Geological Survey, Texas Water Science Center Austin , Texas 78754 , United States
| | - David P Krabbenhoft
- United States Geological Survey, Upper Midwest Water Science Center , Middleton , Wisconsin 53562 , United States
| | - James F Coles
- United States Geological Survey, New England Water Science Center Northborough , Massachusetts 01532 , United States
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24
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Brocza FM, Biester H, Richard JH, Kraemer SM, Wiederhold JG. Mercury Isotope Fractionation in the Subsurface of a Hg(II) Chloride-Contaminated Industrial Legacy Site. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7296-7305. [PMID: 31145601 PMCID: PMC6610540 DOI: 10.1021/acs.est.9b00619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/27/2019] [Accepted: 05/30/2019] [Indexed: 05/24/2023]
Abstract
To understand the transformations of mercury (Hg) species in the subsurface of a HgCl2-contaminated former industrial site in southwest Germany, Hg isotope analysis was combined with an investigation of Hg forms by a four-step sequential extraction protocol (SEP) and pyrolytic thermodesorption. Data from two soil cores revealed that the initial HgCl2 was partly reduced to metallic Hg(0) and that Hg forms of different mobility and oxidation state coexist in the subsurface. The most contaminated sample (K2-8, 802 mg kg-1 Hg) had a bulk δ202Hg value of around -0.43 ± 0.06‰ (2SD), similar to published average values for industrial Hg sources. Other sample signatures varied significantly with depth and between SEP pools. The most Hg-rich samples contained mixtures of Hg(0) and Hg(II) phases, and the water-extractable, mobile Hg pool exhibited heavy δ202Hg values of up to +0.18‰. Sequential water extracts revealed slow dissolution kinetics of mobile Hg pools, continuously releasing isotopically heavy Hg into solution. This was further corroborated by heavy δ202Hg values of groundwater samples. Our results demonstrate that the Hg isotope signature of an industrial contamination source can be significantly altered during the transformations of Hg species in the subsurface, which complicates source tracing applications but offers the possibility of using Hg isotopes as process tracers in contaminated subsurface systems.
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Affiliation(s)
- Flora M. Brocza
- Environmental Geosciences,
Centre for Microbiology and Environmental Systems Science, University of Vienna, Althanstrasse 14, UZA II, 1090 Vienna, Austria
- School of Chemical
and Process Engineering, University of Leeds, 211 Clarendon Road, Leeds LS2 9JT, United Kingdom
| | - Harald Biester
- Institut für Geoökologie, Technische Universität Braunschweig, Langer Kamp 19C, 38106 Braunschweig, Germany
| | - Jan-Helge Richard
- Institut für Geoökologie, Technische Universität Braunschweig, Langer Kamp 19C, 38106 Braunschweig, Germany
- Institute for Hygiene and Environment, Marckmannstraße 129A, 20539 Hamburg, Germany
| | - Stephan M. Kraemer
- Environmental Geosciences,
Centre for Microbiology and Environmental Systems Science, University of Vienna, Althanstrasse 14, UZA II, 1090 Vienna, Austria
| | - Jan G. Wiederhold
- Environmental Geosciences,
Centre for Microbiology and Environmental Systems Science, University of Vienna, Althanstrasse 14, UZA II, 1090 Vienna, Austria
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25
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Sun R. Mercury Stable Isotope Fractionation During Coal Combustion in Coal-Fired Boilers: Reconciling Atmospheric Hg Isotope Observations with Hg Isotope Fractionation Theory. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 102:657-664. [PMID: 30603766 DOI: 10.1007/s00128-018-2531-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
Abstract
Mercury (Hg) stable isotope is a useful tool to understand the transformation of atmospheric Hg. The observation on the enrichment of heavier isotopes in gaseous elemental Hg (GEM) relative to oxidized HgII species in atmosphere cannot be convincingly explained by isotope fractionation of Hg redox processes. This review shows that the large Hg isotope mass dependent fractionation (MDF) in coal-fired boilers is one of the underlying reasons. The reported Hg isotope data of feed coals and their combustion products are first summarized to give a general overview of how Hg isotopes fractionate before Hg discharge from coal-fired boilers. Then, predictive MDF models are discussed to simulate δ202Hg values of different Hg species in coal combustion flue gases. The discharged GEM is predicted to have the highest δ202Hg followed by gaseous HgII and particulate-bound HgII, which is in consistent with the observed MDF pattern of atmospheric Hg species.
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Affiliation(s)
- Ruoyu Sun
- Institute of Surface-Earth System Sciences, Tianjin University, Tianjin, 300072, China.
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26
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Janssen S, Lepak R, Tate M, Ogorek J, DeWild J, Babiarz C, Hurley J, Krabbenhoft D. Rapid pre-concentration of mercury in solids and water for isotopic analysis. Anal Chim Acta 2019; 1054:95-103. [DOI: 10.1016/j.aca.2018.12.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/03/2018] [Accepted: 12/12/2018] [Indexed: 12/13/2022]
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27
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Zhang Y, Wang M, Huang B, Akhtar MS, Hu W, Xie E. Soil mercury accumulation, spatial distribution and its source identification in an industrial area of the Yangtze Delta, China. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 163:230-237. [PMID: 30056336 DOI: 10.1016/j.ecoenv.2018.07.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/12/2018] [Accepted: 07/14/2018] [Indexed: 06/08/2023]
Abstract
Understanding soil mercury (Hg) accumulation, spatial distribution, and its sources is crucial for effective regulation of Hg emissions. We chose a study area covering approximately 100 km2 representing one of the rapid growing industrial towns of the Yangtze River Delta (YRD), China, to explore soil Hg accumulation. In surface soil, total Hg ranged from 310 to 3760 μg/kg, and 53% samples exceeded the most generous Chinese soil critical value (1500 µg/kg). Hg concentration in rice ranged from 10 to 40 µg/kg, and 43% samples exceeded the regulatory critical value (20 µg/kg). Total Hg concentrations in soil profiles gradually decreased, reaching background levels up to 60 cm profile depth. Meanwhile, proportions of mobile, semi-mobile and non-mobile Hg to total Hg at every soil depth were similar, leading us to deduce that soil Hg has accumulated in this area over a long period. Total and bioavailable Hg in topsoil exhibited the highest concentrations in the center of the study area, and radially decreased towards the periphery, which might be explained by the distribution of industry and the prevailing wind. To trace the Hg sources, we selected soil and atmospheric dust samples for isotope analysis. Hg isotopic composition of surface soil (δ202Hg = -0.29 ± 0.10‰ and Δ199Hg = 0.03 ± 0.03‰) was close to that of atmospheric dust (δ202Hg = -0.54 ± 0.10‰ and Δ199Hg = 0.03 ± 0.05‰), but considerably different from Hg isotopic composition in subsoil (δ202Hg = -0.90 ± 0.09‰ and Δ199Hg = -0.04 ± 0.04‰). Thus, we speculated that atmospheric deposition could change Hg isotopic composition in topsoil. Our findings suggest that when Hg atmospheric dust deposition changes Hg levels in surface soil, soil remediation, and crop safety might be compromised.
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Affiliation(s)
- Yanxia Zhang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Mei Wang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China
| | - Biao Huang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | | | - Wenyou Hu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Enze Xie
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
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28
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Guédron S, Amouroux D, Tessier E, Grimaldi C, Barre J, Berail S, Perrot V, Grimaldi M. Mercury Isotopic Fractionation during Pedogenesis in a Tropical Forest Soil Catena (French Guiana): Deciphering the Impact of Historical Gold Mining. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:11573-11582. [PMID: 30222337 DOI: 10.1021/acs.est.8b02186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We used natural mercury (Hg) stable isotopes to investigate the Hg cycle in a rainforest soil catena (French Guiana) partially gold-mined during the early 1950s. Litterfall showed homogeneous Δ199Hg values [-0.18 ± 0.05‰, i.e., a modern gaseous elemental Hg (GEM) isotopic signature]. After litter decomposition, Hg bound to organic matter (OM) is mixed with Hg from pristine (-0.55 ± 0.22‰) or gold-mined (-0.09 ± 0.16‰) mineral materials. Negative Δ199Hg values in deep pristine mineral horizons (-0.60 ± 0.16‰) suggest the transfer of Hg bound to dissolved OM depleted in odd isotopes due to mass-independent fractionation during Hg abiotic reduction. Perennial palm tree leaves collected above gold-mined and pristine soil recorded contrasting Δ199Hg signatures likely resulting from GEM re-emission processes from soils and leaf surfaces. Upslope, soil δ202Hg signatures showed a negative shift (ε ∼ -1‰) with depth attributed to mass-dependent fractionation during Hg sorption and complexation onto iron oxides and dissolved OM. Downslope, higher δ202Hg values in soils resulted from hydromorphy [lower humification, greater Hg(II) reduction, etc.]. The unique Hg isotopic signatures of Amazonian soils probably result in multistep fractionation processes during pedogenesis (millions of years) and in a potentially different Hg isotopic signature of preanthropogenic background GEM.
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Affiliation(s)
- S Guédron
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble , France
| | - D Amouroux
- CNRS/Univ. Pau & Pays Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux-IPREM, UMR5254, 64000 Pau , France
| | - E Tessier
- CNRS/Univ. Pau & Pays Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux-IPREM, UMR5254, 64000 Pau , France
| | - C Grimaldi
- UMR SAS, INRA, Agrocampus Ouest, 35000 Rennes , France
| | - J Barre
- CNRS/Univ. Pau & Pays Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux-IPREM, UMR5254, 64000 Pau , France
| | - S Berail
- CNRS/Univ. Pau & Pays Adour/E2S UPPA, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux-IPREM, UMR5254, 64000 Pau , France
| | - V Perrot
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble , France
| | - M Grimaldi
- Sorbonne Universities, Science Faculty, Paris 06, IRD, CNRS, INRA, UPEC, Univ Paris Diderot, Institute of Ecology and Environmental Sciences, iEES Paris, 75005 Paris , France
- Institut de Recherche pour le Développement, Centre IRD de Cayenne, 97323 Cayenne cedex, France
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29
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Grigg ARC, Kretzschmar R, Gilli RS, Wiederhold JG. Mercury isotope signatures of digests and sequential extracts from industrially contaminated soils and sediments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 636:1344-1354. [PMID: 29913595 DOI: 10.1016/j.scitotenv.2018.04.261] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/12/2018] [Accepted: 04/20/2018] [Indexed: 05/24/2023]
Abstract
Environmental mercury (Hg) pollution is a matter of global concern. Mercury speciation controls its environmental behaviour, and stable isotope ratios can potentially trace Hg movement through environmental compartments. Here we investigated Hg in industrially contaminated soils and sediments (Visp, Valais, Switzerland) using concentration and stable isotope analysis (CV-MC-ICP-MS) of total digests, and a four-step sequential extraction procedure. The sequential extraction employed (1) water (labile Hg species), (2) NaOH or Na4P2O7 (organically-bound Hg), (3) hydroxylamine-HCl (Hg bound to Mn and Fe (oxyhydr)oxides), and (4) aqua regia (residual Hg pools). The majority of Hg was extracted in step 4 and up to 36% in step 2. Mercury bound to organic matter was the dominant source of Hg in water, NaOH and Na4P2O7 extracts. Sulfides and colloidal oxide minerals were possible additional sources of Hg in some samples. The inconsistent comparative performance of NaOH and Na4P2O7 extractions showed that these classical extractants may not extract Hg exclusively from the organically-bound pool. Samples taken at the industrial facility displayed the greatest isotopic variation (δ202Hg: -0.80‰ ± 0.14‰ to 0.25‰ ± 0.13‰, Δ199Hg: -0.10‰ ± 0.03‰ to 0.02‰ ± 0.03‰; all 2SD) whereas downstream of the facility there was much less variation around average values of δ202Hg = -0.47‰ ± 0.11‰ and Δ199Hg = -0.05‰ ± 0.03‰ (1SD, n = 19). We interpret the difference as the result of homogenisation by mixing of canal sediments containing Hg from the various sources at the industrial facility with preservation of the mixed industrial Hg signature downstream. In contrast to previous findings, Hg isotopes in the sequential extracts were largely similar to one another (2SD < 0.14‰), likely demonstrating that the Hg speciation was similar among the extracts. Our results reveal that Hg resides in relatively stable soil pools which record an averaged isotope signature of the industrial sources, potentially facilitating source tracing studies with Hg isotope signatures at larger spatial scales further downstream.
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Affiliation(s)
- Andrew R C Grigg
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, CHN, ETH Zurich, Zurich, Switzerland; Environmental Geochemistry Group, Department of Environmental Geosciences, University of Vienna, Vienna, Austria
| | - Ruben Kretzschmar
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, CHN, ETH Zurich, Zurich, Switzerland
| | - Robin S Gilli
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, CHN, ETH Zurich, Zurich, Switzerland
| | - Jan G Wiederhold
- Environmental Geochemistry Group, Department of Environmental Geosciences, University of Vienna, Vienna, Austria.
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30
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Baptista-Salazar C, Hintelmann H, Biester H. Distribution of mercury species and mercury isotope ratios in soils and river suspended matter of a mercury mining area. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:621-631. [PMID: 29387859 DOI: 10.1039/c7em00443e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mercury (Hg) released by mining activities can be dispersed in the environment, where it is subject to species transformations. Hg isotope ratios have been used to track sources in Hg contaminated areas, although it is unclear to what extent variations in δ-values are attributed to distinct Hg species. Hg was mined as Hg sulphide (cinnabar) in Idrija, Slovenia for centuries. Sediments are loaded with mining-residues (cinnabar and calcine), whereas contaminated soils mainly contain Hg bound to natural organic matter (NOM-Hg) related to atmospheric Hg deposition. Hg released from soils and sediments is transported as suspended matter (SM) in the Idrijca river to the Gulf of Trieste (GT), Italy. We determine Hg isotope ratios in river SM, sediments and soils from the Idrijca-catchment to decipher the Hg isotope ratio variability related to Hg species distribution in different grain-size fractions. δ202Hg values of SM collected from tributaries corresponded to those found in soils ranging from -2.58 to 0.19‰ and from -2.27 to -0.88‰, respectively. Speciation measurements reveal that fine fractions (0.45-20 μm) are dominated by NOM-Hg, while larger fractions contain more cinnabar. More negative δ202Hg values were related to higher proportions of NOM-Hg, which are predominant in soils and SM. Rain events increase SM-loads in the river, mainly due to resuspension of coarse grain-size fractions of bottom sediments bearing larger proportions of cinnabar, which leads to more positive δ202Hg values. The large magnitude of variation in δ202Hg and the smaller magnitude of variation in Δ199Hg (-0.37 to 0.09‰) are likely related to fractionation during ore roasting. Soil samples with high NOM-Hg content show more negative δ202Hg values and larger variation of Δ199Hg. More negative δ202Hg values in GT sediments were rather linked to distant sedimentation of soil derived NOM-Hg than to sedimentation of autochthonous marine material. Heterogeneity in the Idrija ore and ore processing likely produce large variations in the Hg isotopic composition of cinnabar and released metallic Hg, which complicate the differentiation of Hg sources. Combining Hg isotope measurements with solid phase Hg speciation reveals that Hg isotope ratios rather indicate different Hg species and are not necessarily symptomatic for Hg pollution sources.
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Affiliation(s)
- Carluvy Baptista-Salazar
- Institut für Geoökologie, Abt. Umweltgeochemie, Technische Universität Braunschweig, Langer Kamp 19c, Braunschweig, 38106, Germany.
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Jiskra M, Wiederhold JG, Skyllberg U, Kronberg RM, Kretzschmar R. Source tracing of natural organic matter bound mercury in boreal forest runoff with mercury stable isotopes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:1235-1248. [PMID: 28825440 DOI: 10.1039/c7em00245a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Terrestrial runoff represents a major source of mercury (Hg) to aquatic ecosystems. In boreal forest catchments, such as the one in northern Sweden studied here, mercury bound to natural organic matter (NOM) represents a large fraction of mercury in the runoff. We present a method to measure Hg stable isotope signatures of colloidal Hg, mainly complexed by high molecular weight or colloidal natural organic matter (NOM) in natural waters based on pre-enrichment by ultrafiltration, followed by freeze-drying and combustion. We report that Hg associated with high molecular weight NOM in the boreal forest runoff has very similar Hg isotope signatures as compared to the organic soil horizons of the catchment area. The mass-independent fractionation (MIF) signatures (Δ199Hg and Δ200Hg) measured in soils and runoff were in agreement with typical values reported for atmospheric gaseous elemental mercury (Hg0) and distinctly different from reported Hg isotope signatures in precipitation. We therefore suggest that most Hg in the boreal terrestrial ecosystem originated from the deposition of Hg0 through foliar uptake rather than precipitation. Using a mixing model we calculated the contribution of soil horizons to the Hg in the runoff. At moderate to high flow runoff conditions, that prevailed during sampling, the uppermost part of the organic horizon (Oe/He) contributed 50-70% of the Hg in the runoff, while the underlying more humified organic Oa/Ha and the mineral soil horizons displayed a lower mobility of Hg. The good agreement of the Hg isotope results with other source tracing approaches using radiocarbon signatures and Hg : C ratios provides additional support for the strong coupling between Hg and NOM. The exploratory results from this study illustrate the potential of Hg stable isotopes to trace the source of Hg from atmospheric deposition through the terrestrial ecosystem to soil runoff, and provide a basis for more in-depth studies investigating the mobility of Hg in terrestrial ecosystems using Hg isotope signatures.
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Affiliation(s)
- Martin Jiskra
- Soil Chemistry, Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zurich, CHN, CH-8092 Zurich, Switzerland.
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Washburn SJ, Blum JD, Demers JD, Kurz AY, Landis RC. Isotopic Characterization of Mercury Downstream of Historic Industrial Contamination in the South River, Virginia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10965-10973. [PMID: 28885821 DOI: 10.1021/acs.est.7b02577] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Historic point source mercury (Hg) contamination from industrial processes on the South River (Waynesboro, Virginia) ended decades ago, but elevated Hg concentrations persist in the river system. In an effort to better understand Hg sources, mobility, and transport in the South River, we analyzed total Hg (THg) concentrations and Hg stable isotope compositions of streambed sediments, stream bank soils, suspended particles, and filtered surface waters. Samples were collected along a longitudinal transect of the South River, starting upstream of the historic Hg contamination point-source and extending downstream to the confluence with the South Fork Shenandoah River. Analysis of the THg concentration and Hg isotopic composition of these environmental samples indicates that the regional background Hg source is isotopically distinct in both Δ199Hg and δ202Hg from Hg derived from the original source of contamination, allowing the tracing of contamination-sourced Hg throughout the study reach. Three distinct end-members are required to explain the Hg isotopic and concentration variation observed in the South River. A consistent negative offset in δ202Hg values (∼0.28‰) was observed between Hg in the suspended particulate and dissolved phases, and this fractionation provides insight into the processes governing partitioning and transport of Hg in this contaminated river system.
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Affiliation(s)
- Spencer J Washburn
- Department of Earth and Environmental Sciences, University of Michigan , 2534 C.C. Little Building, 1100 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan , 2534 C.C. Little Building, 1100 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Jason D Demers
- Department of Earth and Environmental Sciences, University of Michigan , 2534 C.C. Little Building, 1100 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Aaron Y Kurz
- Department of Earth and Environmental Sciences, University of Michigan , 2534 C.C. Little Building, 1100 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Richard C Landis
- RichLand Consulting, LLC. , Lincoln University, Pennsylvania 19352, United States
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Tang S, Feng C, Feng X, Zhu J, Sun R, Fan H, Wang L, Li R, Mao T, Zhou T. Stable isotope composition of mercury forms in flue gases from a typical coal-fired power plant, Inner Mongolia, northern China. JOURNAL OF HAZARDOUS MATERIALS 2017; 328:90-97. [PMID: 28092743 DOI: 10.1016/j.jhazmat.2017.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/08/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
Mercury forms emitted from coal combustion via air pollution control devices are speculated to carry different Hg isotope signatures. Yet, their Hg isotope composition is still not reported. Here, we present the first onsite Hg isotope data for gaseous elemental Hg (GEM) and gaseous oxidized Hg (GOM) of flue gases from a typical lignite-fired power plant (CFPP). Significant mass dependent fractionation (MDF) and insignificant mass independent fractionation (MIF) are observed between feed coal and coal combustion products. As compared to feed coal (δ202Hg=-2.04±0.25‰), bottom ash, GEM and GOM in flue gases before and after wet flue gas desulfurization system significantly enrich heavy Hg isotopes by 0.7-2.6‰ in δ202Hg, while fly ash, desulfurization gypsum and waste water show slight but insignificant enrichment of light Hg isotopes. GEM is significantly enriched heavy Hg isotopes compared to GOM and Hg in fly ash. Our observations verify the previous speculation on Hg isotope fractionation mechanism in CFPPs, and suggest a kinetically-controlled mass dependent Hg isotope fractionation during transformation of Hg forms in flue gases. Finally, our data are compared to Hg isotope compositions of atmospheric Hg pools, suggesting that coal combustion Hg emission is likely an important atmospheric Hg contributor.
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Affiliation(s)
- Shunlin Tang
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China.
| | - Chaohui Feng
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China
| | - Jianming Zhu
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, 100086, China
| | - Ruoyu Sun
- CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Huipeng Fan
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China
| | - Lina Wang
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China
| | - Ruiyang Li
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China
| | - Tonghua Mao
- Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, China
| | - Ting Zhou
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China
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Donovan PM, Blum JD, Singer MB, Marvin-DiPasquale M, Tsui MTK. Methylmercury degradation and exposure pathways in streams and wetlands impacted by historical mining. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 568:1192-1203. [PMID: 27234290 DOI: 10.1016/j.scitotenv.2016.04.139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 06/05/2023]
Abstract
Monomethyl mercury (MMHg) and total mercury (THg) concentrations and Hg stable isotope ratios (δ(202)Hg and Δ(199)Hg) were measured in sediment and aquatic organisms from Cache Creek (California Coast Range) and Yolo Bypass (Sacramento Valley). Cache Creek sediment had a large range in THg (87 to 3870ng/g) and δ(202)Hg (-1.69 to -0.20‰) reflecting the heterogeneity of Hg mining sources in sediment. The δ(202)Hg of Yolo Bypass wetland sediment suggests a mixture of high and low THg sediment sources. Relationships between %MMHg (the percent ratio of MMHg to THg) and Hg isotope values (δ(202)Hg and Δ(199)Hg) in fish and macroinvertebrates were used to identify and estimate the isotopic composition of MMHg. Deviation from linear relationships was found between %MMHg and Hg isotope values, which is indicative of the bioaccumulation of isotopically distinct pools of MMHg. The isotopic composition of pre-photodegraded MMHg (i.e., subtracting fractionation from photochemical reactions) was estimated and contrasting relationships were observed between the estimated δ(202)Hg of pre-photodegraded MMHg and sediment IHg. Cache Creek had mass dependent fractionation (MDF; δ(202)Hg) of at least -0.4‰ whereas Yolo Bypass had MDF of +0.2 to +0.5‰. This result supports the hypothesis that Hg isotope fractionation between IHg and MMHg observed in rivers (-MDF) is unique compared to +MDF observed in non-flowing water environments such as wetlands, lakes, and the coastal ocean.
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Affiliation(s)
- Patrick M Donovan
- University of Michigan, Department of Earth and Environmental Sciences, 1100 N., University Ave., Ann Arbor, MI 48109, USA.
| | - Joel D Blum
- University of Michigan, Department of Earth and Environmental Sciences, 1100 N., University Ave., Ann Arbor, MI 48109, USA
| | - Michael Bliss Singer
- University of St Andrews, Department of Earth and Environmental Sciences, North St., St. Andrews, KY16 9AL, UK; Earth Research Institute, University of California Santa Barbara, Santa Barbara, CA, 91306, USA
| | | | - Martin T K Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
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Jiménez-Moreno M, Barre JPG, Perrot V, Bérail S, Rodríguez Martín-Doimeadios RC, Amouroux D. Sources and fate of mercury pollution in Almadén mining district (Spain): Evidences from mercury isotopic compositions in sediments and lichens. CHEMOSPHERE 2016; 147:430-438. [PMID: 26774309 DOI: 10.1016/j.chemosphere.2015.12.094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 12/04/2015] [Accepted: 12/23/2015] [Indexed: 06/05/2023]
Abstract
Variations in mercury (Hg) isotopic compositions have been scarcely investigated until now in the Almadén mining district (Spain), which is one of the most impacted Hg areas worldwide. In this work, we explore and compare Hg isotopic signatures in sediments and lichens from Almadén mining district and its surroundings in order to identify and trace Hg aquatic and atmospheric contamination sources. No statistically significant mass independent fractionation was observed in sediments, while negative Δ(201)Hg values from -0.12 to -0.21‰ (2SD = 0.06‰) were found in lichens. A large range of δ(202)Hg values were reported in sediments, from -1.86 ± 0.21‰ in La Serena Reservoir sites far away from the pollution sources to δ(202)Hg values close to zero in sediments directly influenced by Almadén mining district, whereas lichens presented δ(202)Hg values from -1.95 to -0.40‰ (2SD = 0.15‰). A dilution or mixing trend in Hg isotope signatures versus the distance to the mine was found in sediments along the Valdeazogues River-La Serena Reservoir system and in lichens. This suggests that Hg isotope fingerprints in these samples are providing a direct assessment of Hg inputs and exposure from the mining district, and potential information on diffuse atmospheric contamination and/or geochemical alteration processes in less contaminated sites over the entire hydrosystem. This study confirms the applicability of Hg isotope signatures in lichens and sediments as an effective and complementary tool for tracing aquatic and atmospheric Hg contamination sources and a better constraint of the spatial and temporal fate of Hg released by recent or ancient mining activities.
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Affiliation(s)
- María Jiménez-Moreno
- Laboratoire de Chimie Analytique, Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), CNRS-UPPA-UMR-5254, Hélioparc, 2 Avenue du Président Pierre Angot, Pau F-64053, France; Department of Analytical Chemistry and Food Technology, Faculty of Environmental Sciences and Biochemistry, University of Castilla-La Mancha, Avenida Carlos III s/n, Toledo E-45071, Spain.
| | - Julien P G Barre
- Laboratoire de Chimie Analytique, Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), CNRS-UPPA-UMR-5254, Hélioparc, 2 Avenue du Président Pierre Angot, Pau F-64053, France
| | - Vincent Perrot
- Laboratoire de Chimie Analytique, Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), CNRS-UPPA-UMR-5254, Hélioparc, 2 Avenue du Président Pierre Angot, Pau F-64053, France
| | - Sylvain Bérail
- Laboratoire de Chimie Analytique, Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), CNRS-UPPA-UMR-5254, Hélioparc, 2 Avenue du Président Pierre Angot, Pau F-64053, France
| | - Rosa C Rodríguez Martín-Doimeadios
- Department of Analytical Chemistry and Food Technology, Faculty of Environmental Sciences and Biochemistry, University of Castilla-La Mancha, Avenida Carlos III s/n, Toledo E-45071, Spain
| | - David Amouroux
- Laboratoire de Chimie Analytique, Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), CNRS-UPPA-UMR-5254, Hélioparc, 2 Avenue du Président Pierre Angot, Pau F-64053, France.
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Donovan PM, Blum JD, Singer MB, Marvin-DiPasquale M, Tsui MTK. Isotopic Composition of Inorganic Mercury and Methylmercury Downstream of a Historical Gold Mining Region. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1691-702. [PMID: 26789018 DOI: 10.1021/acs.est.5b04413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We measured total mercury (THg) and monomethyl mercury (MMHg) concentrations and mercury (Hg) isotopic compositions in sediment and aquatic organisms from the Yuba River (California, USA) to identify Hg sources and biogeochemical transformations downstream of a historical gold mining region. Sediment THg concentrations and δ(202)Hg decreased from the upper Yuba Fan to the lower Yuba Fan and the Feather River. These results are consistent with the release of Hg during gold mining followed by downstream mixing and dilution. The Hg isotopic composition of Yuba Fan sediment (δ(202)Hg = -0.38 ± 0.17‰ and Δ(199)Hg = 0.04 ± 0.03‰; mean ± 1 SD, n = 7) provides a fingerprint of inorganic Hg (IHg) that could be methylated locally or after transport downstream. The isotopic composition of MMHg in the Yuba River food web was estimated using biota with a range of %MMHg (the percent of THg present as MMHg) and compared to IHg in sediment, algae, and the food web. The estimated δ(202)Hg of MMHg prior to photodegradation (-1.29 to -1.07‰) was lower than that of IHg and we suggest this is due to mass-dependent fractionation (MDF) of up to -0.9‰ between IHg and MMHg. This result is in contrast to net positive MDF (+0.4 to +0.8‰) previously observed in lakes, estuaries, coastal oceans, and forests. We hypothesize that this unique relationship could be due to differences in the extent or pathway of biotic MMHg degradation in stream environments.
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Affiliation(s)
- Patrick M Donovan
- Department of Earth and Environmental Sciences, University of Michigan , 1100 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Joel D Blum
- Department of Earth and Environmental Sciences, University of Michigan , 1100 N. University Avenue, Ann Arbor, Michigan 48109, United States
| | - Michael Bliss Singer
- Department of Earth and Environmental Sciences, University of St Andrews , North Street, St Andrews, KY16 9AL U.K
- Earth Research Institute, University of California Santa Barbara , Santa Barbara, California 93106 United States
| | | | - Martin T K Tsui
- Department of Biology, University of North Carolina at Greensboro , Greensboro, North Carolina 27402, United States
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Smith RS, Wiederhold JG, Kretzschmar R. Mercury isotope fractionation during precipitation of metacinnabar (β-HgS) and montroydite (HgO). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4325-4334. [PMID: 25782104 DOI: 10.1021/acs.est.5b00409] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To utilize stable Hg isotopes as a tracer for Hg cycling and pollution sources in the environment, it is imperative that fractionation factors for important biogeochemical processes involving Hg are determined. Here, we report experimental results on Hg isotope fractionation during precipitation of metacinnabar (β-HgS) and montroydite (HgO). In both systems, we observed mass-dependent enrichments of light Hg isotopes in the precipitates relative to the dissolved Hg. Precipitation of β-HgS appeared to follow equilibrium isotope fractionation with an enrichment factor ε(202)Hg(precipitate-supernatant) of -0.63‰. Precipitation of HgO resulted in kinetic isotope fractionation, which was described by a Rayleigh model with an enrichment factor of -0.32‰. Small mass-independent fractionation was observed in the HgS system, presumably related to nuclear volume fractionation. We propose that Hg isotope fractionation in the HgS system occurred in solution during the transition of O- to S-coordination of Hg(II), consistent with theoretical predictions. In the HgO system, fractionation was presumably caused by the faster precipitation of light Hg isotopes, and no isotopic exchange between solid and solution was observed on the timescale investigated. The results of this work emphasize the importance of Hg solution speciation and suggest that bonding partners of Hg in solution complexes may control the overall isotope fractionation. The determined fractionation factor and mechanistic insights will have implications for the interpretation of Hg isotope signatures and their use as an environmental tracer.
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Affiliation(s)
- Robin S Smith
- †Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CH-8092 Zurich, Switzerland
- ‡Isotope Geochemistry Group, Institute of Geochemistry and Petrology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Jan G Wiederhold
- †Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CH-8092 Zurich, Switzerland
- ‡Isotope Geochemistry Group, Institute of Geochemistry and Petrology, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Ruben Kretzschmar
- †Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, CH-8092 Zurich, Switzerland
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Wiederhold JG. Metal stable isotope signatures as tracers in environmental geochemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:2606-24. [PMID: 25640608 DOI: 10.1021/es504683e] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The biogeochemical cycling of metals in natural systems is often accompanied by stable isotope fractionation which can now be measured due to recent analytical advances. In consequence, a new research field has emerged over the last two decades, complementing the traditional stable isotope systems (H, C, O, N, S) with many more elements across the periodic table (Li, B, Mg, Si, Cl, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Ge, Se, Br, Sr, Mo, Ag, Cd, Sn, Sb, Te, Ba, W, Pt, Hg, Tl, U) which are being explored and potentially applicable as novel geochemical tracers. This review presents the application of metal stable isotopes as source and process tracers in environmental studies, in particular by using mixing and Rayleigh model approaches. The most important concepts of mass-dependent and mass-independent metal stable isotope fractionation are introduced, and the extent of natural isotopic variations for different elements is compared. A particular focus lies on a discussion of processes (redox transformations, complexation, sorption, precipitation, dissolution, evaporation, diffusion, biological cycling) which are able to induce metal stable isotope fractionation in environmental systems. Additionally, the usefulness and limitations of metal stable isotope signatures as tracers in environmental geochemistry are discussed and future perspectives presented.
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Affiliation(s)
- Jan G Wiederhold
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich , 8092 Zurich, Switzerland
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Yin R, Feng X, Chen B, Zhang J, Wang W, Li X. Identifying the sources and processes of mercury in subtropical estuarine and ocean sediments using Hg isotopic composition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:1347-1355. [PMID: 25565343 DOI: 10.1021/es504070y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The concentrations and isotopic compositions of mercury (Hg) in surface sediments of the Pearl River Estuary (PRE) and the South China Sea (SCS) were analyzed. The data revealed significant differences between the total Hg (THg) in fine-grained sediments collected from the PRE (8-251 μg kg(-1)) and those collected from the SCS (12-83 μg kg(-1)). Large spatial variations in Hg isotopic compositions were observed in the SCS (δ(202)Hg, from -2.82 to -2.10‰; Δ(199)Hg, from +0.21 to +0.45‰) and PRE (δ(202)Hg, from -2.80 to -0.68‰; Δ(199)Hg, from -0.15 to +0.16‰). The large positive Δ(199)Hg in the SCS indicated that a fraction of Hg has undergone Hg(2+) photoreduction processes prior to incorporation into the sediments. The relatively negative Δ(199)Hg values in the PRE indicated that photoreduction of Hg is not the primary route for the removal of Hg from the water column. The riverine input of fine particles played an important role in transporting Hg to the PRE sediments. In the deep ocean bed of the SCS, source-related signatures of Hg isotopes may have been altered by natural geochemical processes (e.g., Hg(2+) photoreduction and preferential adsorption processes). Using Hg isotope compositions, we estimate that river deliveries of Hg from industrial and urban sources and natural soils could be the main inputs of Hg to the PRE. However, the use of Hg isotopes as tracers in source attribution could be limited because of the isotope fractionation by natural processes in the SCS.
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Affiliation(s)
- Runsheng Yin
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University , Hung Hom, Kowloon, Hong Kong
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Smith RS, Wiederhold JG, Jew AD, Brown GE, Bourdon B, Kretzschmar R. Stable Hg isotope signatures in creek sediments impacted by a former Hg mine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:767-76. [PMID: 25489982 DOI: 10.1021/es503442p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The goal of this study was to investigate the Hg stable isotope signatures of sediments in San Carlos Creek downstream of the former Hg mine New Idria, CA, USA and to relate the results to previously studied Hg isotope signatures of unroasted ore waste and calcine materials in the mining area. New Idria unroasted ore waste was reported to have a narrow δ(202)Hg range (−0.09 to 0.16‰), while roasted calcine materials exhibited a very large variability in δ(202)Hg (−5.96 to 14.5‰). In this study, creek sediment samples were collected in the stream bed from two depths (0–10 and 10–20 cm) at 10 locations between the mine adit and 28 km downstream. The sediment samples were size-fractionated into sand, silt, and (if possible) clay fractions as well as hand-picked calcine pebbles. The sediment samples contained highly elevated Hg concentrations (8.2 to 647 μg g(–1)) and displayed relatively narrow mass-dependent fractionation (MDF, δ(202)Hg; ± 0.08‰, 2SD) ranges (−0.58 to 0.24‰) and little to no mass-independent fractionation (MIF, Δ(199)Hg; ± 0.04‰, 2SD) (0.00 to 0.10‰), similar to what was observed previously for the unroasted ore waste. However, due to the highly variable and overlapping δ(202)Hg signatures of the calcines, they could not be ruled out as source of Hg to the creek sediments. Overall, our results suggest that analyzing creek sediments downstream of former Hg mines can provide a more reliable Hg isotope source signature for tracing studies at larger spatial scales, than analyzing the isotopically highly heterogeneous tailing piles typically found at former mining sites. Creek sediments carry an integrated isotope signature of Hg transported away from the mine with runoff into the creek, eventually affecting ecosystems downstream.
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Wiederhold JG, Skyllberg U, Drott A, Jiskra M, Jonsson S, Björn E, Bourdon B, Kretzschmar R. Mercury isotope signatures in contaminated sediments as a tracer for local industrial pollution sources. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:177-185. [PMID: 25437501 DOI: 10.1021/es5044358] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) may cause characteristic isotope signatures of different mercury (Hg) sources and help understand transformation processes at contaminated sites. Here, we present Hg isotope data of sediments collected near industrial pollution sources in Sweden contaminated with elemental liquid Hg (mainly chlor-alkali industry) or phenyl-Hg (paper industry). The sediments exhibited a wide range of total Hg concentrations from 0.86 to 99 μg g(-1), consisting dominantly of organically-bound Hg and smaller amounts of sulfide-bound Hg. The three phenyl-Hg sites showed very similar Hg isotope signatures (MDF δ(202)Hg: -0.2‰ to -0.5‰; MIF Δ(199)Hg: -0.05‰ to -0.10‰). In contrast, the four sites contaminated with elemental Hg displayed much greater variations (δ(202)Hg: -2.1‰ to 0.6‰; Δ(199)Hg: -0.19‰ to 0.03‰) but with distinct ranges for the different sites. Sequential extractions revealed that sulfide-bound Hg was in some samples up to 1‰ heavier in δ(202)Hg than organically-bound Hg. The selectivity of the sequential extraction was tested on standard materials prepared with enriched Hg isotopes, which also allowed assessing isotope exchange between different Hg pools. Our results demonstrate that different industrial pollution sources can be distinguished on the basis of Hg isotope signatures, which may additionally record fractionation processes between different Hg pools in the sediments.
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Affiliation(s)
- Jan G Wiederhold
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich , CH-8092 Zurich, Switzerland
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Da Pieve F, Stankowski M, Hogan C. Electronic structure calculations of mercury mobilization from mineral phases and photocatalytic removal from water and the atmosphere. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 493:596-605. [PMID: 24982025 DOI: 10.1016/j.scitotenv.2014.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
Mercury is a hazardous environmental pollutant mobilized from natural sources, and anthropogenically contaminated and disturbed areas. Current methods to assess mobility and environmental impact are mainly based on field measurements, soil monitoring, and kinetic modelling. In order to understand in detail the extent to which different mineral sources can give rise to mercury release it is necessary to investigate the complexity at the microscopic level and the possible degradation/dissolution processes. In this work, we investigated the potential for mobilization of mercury structurally trapped in three relevant minerals occurring in hot spring environments and mining areas, namely, cinnabar (α-HgS), corderoite (α-Hg3S2Cl2), and mercuric chloride (HgCl2). Quantum chemical methods based on density functional theory as well as more sophisticated approaches are used to assess the possibility of a) direct photoreduction and formation of elemental Hg at the surface of the minerals, providing a path for ready release in the environment; and b) reductive dissolution of the minerals in the presence of solutions containing halogens. Furthermore, we study the use of TiO2 as a potential photocatalyst for decontamination of polluted waters (mainly Hg(2+)-containing species) and air (atmospheric Hg(0)). Our results partially explain the observed pathways of Hg mobilization from relevant minerals and the microscopic mechanisms behind photocatalytic removal of Hg-based pollutants. Possible sources of disagreement with observations are discussed and further improvements to our approach are suggested.
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Affiliation(s)
- Fabiana Da Pieve
- Université libre de Bruxelles (U.L.B.), Boulevard du Triomphe, CP 231, Campus Plaine, B-1050 Bruxelles, Belgium.
| | - Martin Stankowski
- LU Open Innovation Center, Lund University, Box 117, SE-221 00 Lund, Sweden; European Theoretical Spectroscopy Facility (ETSF)
| | - Conor Hogan
- European Theoretical Spectroscopy Facility (ETSF); Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia (CNR-ISM), University of Rome "Tor Vergata", via Fosso del Cavaliere 100, 00133 Rome, Italy; Physics Department, University of Rome "Tor Vergata", via Fosso del Cavaliere 100, 00133 Rome, Italy
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