1
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Gustin MS, Dunham-Cheatham SM, Lyman S, Horvat M, Gay DA, Gačnik J, Gratz L, Kempkes G, Khalizov A, Lin CJ, Lindberg SE, Lown L, Martin L, Mason RP, MacSween K, Vijayakumaran Nair S, Nguyen LSP, O'Neil T, Sommar J, Weiss-Penzias P, Zhang L, Živković I. Measurement of Atmospheric Mercury: Current Limitations and Suggestions for Paths Forward. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:12853-12864. [PMID: 38982755 DOI: 10.1021/acs.est.4c06011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Mercury (Hg) researchers have made progress in understanding atmospheric Hg, especially with respect to oxidized Hg (HgII) that can represent 2 to 20% of Hg in the atmosphere. Knowledge developed over the past ∼10 years has pointed to existing challenges with current methods for measuring atmospheric Hg concentrations and the chemical composition of HgII compounds. Because of these challenges, atmospheric Hg experts met to discuss limitations of current methods and paths to overcome them considering ongoing research. Major conclusions included that current methods to measure gaseous oxidized and particulate-bound Hg have limitations, and new methods need to be developed to make these measurements more accurate. Developing analytical methods for measurement of HgII chemistry is challenging. While the ultimate goal is the development of ultrasensitive methods for online detection of HgII directly from ambient air, in the meantime, new surfaces are needed on which HgII can be quantitatively collected and from which it can be reversibly desorbed to determine HgII chemistry. Discussion and identification of current limitations, described here, provide a basis for paths forward. Since the atmosphere is the means by which Hg is globally distributed, accurately calibrated measurements are critical to understanding the Hg biogeochemical cycle.
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Affiliation(s)
- Mae Sexauer Gustin
- College of Biotechnology, Natural Resources & Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Sarrah M Dunham-Cheatham
- College of Biotechnology, Natural Resources & Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Seth Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
- Jožef Stefan International Postgraduate School, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
| | - David A Gay
- Wisconsin State Laboratory of Hygiene, University of Wisconsin Madison, Madison, Wisconsin 53707-7996, United States
| | - Jan Gačnik
- College of Biotechnology, Natural Resources & Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Lynne Gratz
- Chemistry Department and Environmental Studies Program, Reed College, Portland, Oregon 97202, United States
| | | | - Alexei Khalizov
- New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Che-Jen Lin
- Lamar University, Beaumont, Texas 77710, United States
| | - Steven E Lindberg
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Livia Lown
- College of Biotechnology, Natural Resources & Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Lynwill Martin
- South Africa Weather Service, Cape Town 7525, South Africa
| | - Robert Peter Mason
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, United States
| | - Katrina MacSween
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change, Toronto, Ontario M3H 5T4, Canada
| | - Sreekanth Vijayakumaran Nair
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
- Jožef Stefan International Postgraduate School, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
| | - Ly Sy Phu Nguyen
- Faculty of Environment, University of Science, Vietnam National University, Ho Chi Minh City 700000,Vietnam
| | - Trevor O'Neil
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Jonas Sommar
- Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550009, China
| | - Peter Weiss-Penzias
- University of California-Santa Cruz, Santa Cruz, California 95064, United States
| | - Lei Zhang
- School of the Environment, Nanjing University, Nanjing 210023, China
| | - Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
- Jožef Stefan International Postgraduate School, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia
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2
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Elgiar TR, Lyman SN, Andron TD, Gratz L, Hallar AG, Horvat M, Vijayakumaran Nair S, O'Neil T, Volkamer R, Živković I. Traceable Calibration of Atmospheric Oxidized Mercury Measurements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10706-10716. [PMID: 38850513 DOI: 10.1021/acs.est.4c02209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2024]
Abstract
Most previous measurements of oxidized mercury were collected using a method now known to be biased low. In this study, a dual-channel system with an oxidized mercury detection limit of 6-12 pg m-3 was deployed alongside a permeation tube-based automated calibrator at a mountain top site in Steamboat Springs Colorado, USA, in 2021 and 2022. Permeation tubes containing elemental mercury and mercury halides were characterized via an International System of Units (SI)-traceable gravimetric method and gas chromatography/mass spectrometry before deployment in the calibrator. The dual-channel system recovered 97 ± 4 and 100 ± 8% (±standard deviation) of injected elemental mercury and HgBr2, respectively. Total Hg permeation rates and Hg speciation from the gravimetric method, the chromatography system, the dual-channel system, and an independent SI-traceable measurement method performed at the Jožef Stefan Institute laboratory were all comparable within the respective uncertainties of each method. These are the first measurements of oxidized mercury at low environmental concentrations that have been verified against an SI-traceable calibration system in field conditions while sampling ambient air, and they show that accurate, routinely calibrated oxidized mercury measurements are achievable.
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Affiliation(s)
- Tyler R Elgiar
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Seth N Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
- Department of Chemistry and Biochemistry, Utah State University, Logan ,Utah 84322, United States
| | - Teodor D Andron
- JoŽef Stefan Institute, Ljubljana 1000, Slovenia
- JoŽef Stefan International Postgraduate School, Ljubljana 1000, Slovenia
| | - Lynne Gratz
- Reed College, Portland, Oregon 97202, United States
| | - A Gannet Hallar
- Department of Atmospheric Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Milena Horvat
- JoŽef Stefan Institute, Ljubljana 1000, Slovenia
- JoŽef Stefan International Postgraduate School, Ljubljana 1000, Slovenia
| | - Sreekanth Vijayakumaran Nair
- JoŽef Stefan Institute, Ljubljana 1000, Slovenia
- JoŽef Stefan International Postgraduate School, Ljubljana 1000, Slovenia
| | - Trevor O'Neil
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Rainer Volkamer
- Department of Chemistry & CIRES, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Igor Živković
- JoŽef Stefan Institute, Ljubljana 1000, Slovenia
- JoŽef Stefan International Postgraduate School, Ljubljana 1000, Slovenia
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3
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Magand O, Angot H, Bertrand Y, Sonke JE, Laffont L, Duperray S, Collignon L, Boulanger D, Dommergue A. Over a decade of atmospheric mercury monitoring at Amsterdam Island in the French Southern and Antarctic Lands. Sci Data 2023; 10:836. [PMID: 38016986 PMCID: PMC10684586 DOI: 10.1038/s41597-023-02740-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/09/2023] [Indexed: 11/30/2023] Open
Abstract
The Minamata Convention, a global and legally binding treaty that entered into force in 2017, aims to protect human health and the environment from harmful mercury (Hg) effects by reducing anthropogenic Hg emissions and environmental levels. The Conference of the Parties is to periodically evaluate the Convention's effectiveness, starting in 2023, using existing monitoring data and observed trends. Monitoring atmospheric Hg levels has been proposed as a key indicator. However, data gaps exist, especially in the Southern Hemisphere. Here, we present over a decade of atmospheric Hg monitoring data at Amsterdam Island (37.80°S, 77.55°E), in the remote southern Indian Ocean. Datasets include gaseous elemental and oxidised Hg species ambient air concentrations from either active/continuous or passive/discrete acquisition methods, and annual total Hg wet deposition fluxes. These datasets are made available to the community to support policy-making and further scientific advancements.
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Affiliation(s)
- Olivier Magand
- Observatoire des Sciences de l'Univers à La Réunion (OSU-R), UAR 3365, CNRS, Université de La Réunion, Météo France, 97744, Saint-Denis, La Réunion, France
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, Grenoble, France
| | - Hélène Angot
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, Grenoble, France.
| | - Yann Bertrand
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, Grenoble, France
| | - Jeroen E Sonke
- Géosciences Environnement Toulouse, CNRS/IRD, Université Paul Sabatier Toulouse 3, Toulouse, France
| | - Laure Laffont
- Géosciences Environnement Toulouse, CNRS/IRD, Université Paul Sabatier Toulouse 3, Toulouse, France
| | - Solène Duperray
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, Grenoble, France
| | - Léa Collignon
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, Grenoble, France
| | | | - Aurélien Dommergue
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP, IGE, Grenoble, France.
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4
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Year-round trace gas measurements in the central Arctic during the MOSAiC expedition. Sci Data 2022; 9:723. [PMID: 36434022 PMCID: PMC9700757 DOI: 10.1038/s41597-022-01769-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/11/2022] [Indexed: 11/26/2022] Open
Abstract
Despite the key role of the Arctic in the global Earth system, year-round in-situ atmospheric composition observations within the Arctic are sparse and mostly rely on measurements at ground-based coastal stations. Measurements of a suite of in-situ trace gases were performed in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. These observations give a comprehensive picture of year-round near-surface atmospheric abundances of key greenhouse and trace gases, i.e., carbon dioxide, methane, nitrous oxide, ozone, carbon monoxide, dimethylsulfide, sulfur dioxide, elemental mercury, and selected volatile organic compounds (VOCs). Redundancy in certain measurements supported continuity and permitted cross-evaluation and validation of the data. This paper gives an overview of the trace gas measurements conducted during MOSAiC and highlights the high quality of the monitoring activities. In addition, in the case of redundant measurements, merged datasets are provided and recommended for further use by the scientific community.
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5
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Davis M, Lu J. Calibration Sources for Gaseous Oxidized Mercury: A Review of Source Design, Performance, and Operational Parameters. Crit Rev Anal Chem 2022:1-10. [PMID: 36223220 DOI: 10.1080/10408347.2022.2131373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Mercury is a neurotoxin that, unlike many localized industrial pollutants, spreads globally through atmospheric transport. Mercury in the atmosphere is operationally partitioned into gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (TPM). Although GOM makes up only a small fraction of Hg in the free troposphere under normal conditions, its role in the dry and wet deposition of mercury makes GOM a significant species for understanding the transport and fate of mercury in the atmosphere. Although instruments for atmospheric mercury speciation are commercially available, significant uncertainty is associated with the current speciation methods, from sample collection to calibration, for GOM measurements. This paper examines the custom-made calibration sources that have been developed for GOM measuring instruments, evaluates the factors influencing the source performance, and synthesizes recommendations for the design and operation of GOM calibration sources in the future.
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Affiliation(s)
- Matthew Davis
- Department of Chemistry and Biology, Ryerson University, Toronto, Canada
| | - Julia Lu
- Department of Chemistry and Biology, Ryerson University, Toronto, Canada
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6
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Liu K, Wu Q, Wang S, Chang X, Tang Y, Wang L, Liu T, Zhang L, Zhao Y, Wang Q, Chen J. Improved atmospheric mercury simulation using updated gas-particle partition and organic aerosol concentrations. J Environ Sci (China) 2022; 119:106-118. [PMID: 35934455 DOI: 10.1016/j.jes.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/29/2022] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
The gaseous or particulate forms of divalent mercury (HgII) significantly impact the spatial distribution of atmospheric mercury concentration and deposition flux (FLX). In the new nested-grid GEOS-Chem model, we try to modify the HgII gas-particle partitioning relationship with synchronous and hourly observations at four sites in China. Observations of gaseous oxidized Hg (GOM), particulate-bound Hg (PBM), and PM2.5 were used to derive an empirical gas-particle partitioning coefficient as a function of temperature (T) and organic aerosol (OA) concentrations under different relative humidity (RH). Results showed that with increasing RH, the dominant process of HgII gas-particle partitioning changed from physical adsorption to chemical desorption. And the dominant factor of HgII gas-particle partitioning changed from T to OA concentrations. We thus improved the simulated OA concentration field by introducing intermediate-volatility and semi-volatile organic compounds (I/SVOCs) emission inventory into the model framework and refining the volatile distributions of I/SVOCs according to new filed tests in the recent literatures. Finally, normalized mean biases (NMBs) of monthly gaseous element mercury (GEM), GOM, PBM, WFLX were reduced from -33%-29%, 95%-300%, 64%-261%, 117%-122% to -13%-0%, -20%-80%, -31%-50%, -17%-23%. The improved model explains 69%-98% of the observed atmospheric Hg decrease during 2013-2020 and can serve as a useful tool to evaluate the effectiveness of the Minamata Convention on Mercury.
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Affiliation(s)
- Kaiyun Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Qingru Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Shuxiao Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China.
| | - Xing Chang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Yi Tang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Long Wang
- Institute of Atmospheric Environment, Guangdong provincial academy of environmental science, Guangzhou 510045, China
| | - Tonghao Liu
- China National Environmental Monitoring Centre, Beijing 100012, China
| | - Lei Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Yu Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Qin'geng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Jinsheng Chen
- Center for Excellence in Regional Atmos. Environ., Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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7
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Lyman SN, Elgiar T, Gustin MS, Dunham-Cheatham SM, David LM, Zhang L. Evidence against Rapid Mercury Oxidation in Photochemical Smog. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11225-11235. [PMID: 35877386 DOI: 10.1021/acs.est.2c02224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Mercury pollution is primarily emitted to the atmosphere, and atmospheric transport and chemical processes determine its fate in the environment, but scientific understanding of atmospheric mercury chemistry is clouded in uncertainty. Mercury oxidation by atomic bromine in the Arctic and the upper atmosphere is well established, but less is understood about oxidation pathways in conditions of anthropogenic photochemical smog. Many have observed rapid increases in oxidized mercury under polluted conditions, but it has not been clearly demonstrated that these increases are the result of local mercury oxidation. We measured elemental and oxidized mercury in an area that experienced abundant photochemical activity (ozone >100 ppb) during winter inversion (i.e., cold air pools) conditions that restricted entrainment of air from the oxidized mercury-rich upper atmosphere. Under these conditions, oxidized mercury concentrations decreased day-upon-day, even as ozone and other pollutants increased dramatically. A box model that incorporated rapid kinetics for reactions of elemental mercury with ozone and OH radical overestimated observed oxidized mercury, while incorporation of slower, more widely accepted reaction rates did not. Our results show that rapid gas-phase mercury oxidation by ozone and OH in photochemical smog is unlikely.
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Affiliation(s)
- Seth N Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Tyler Elgiar
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, Nevada 89557, United States
| | - Sarrah M Dunham-Cheatham
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, Nevada 89557, United States
| | - Liji M David
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Lei Zhang
- School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China
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8
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Tang Y, Wang S, Li G, Han D, Liu K, Li Z, Wu Q. Elevated Gaseous Oxidized Mercury Revealed by a Newly Developed Speciated Atmospheric Mercury Monitoring System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7707-7715. [PMID: 35607915 DOI: 10.1021/acs.est.2c01011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Gaseous oxidized mercury (Hg2+) monitoring is one of the largest challenges in the mercury research field, where existing methods cannot simultaneously satisfy the measurement requirements of both accuracy and time precision, especially in high-particulate environments. Here, we verified that dual-stage cation exchange membrane (CEM) sampler is incapable of gaseous elemental mercury (Hg0) uptake even if particulate matter is trapped on CEM, whereas the Hg2+ capture efficiency of the sampler is more than 90%. We then developed a Cation Exchange Membrane-Coupled Speciated Atmospheric Mercury Monitoring System (CSAMS) by coupling the dual-stage CEM sampler with the commercial Tekran 2537/1130/1135 system and configuring a new sampling and analysis procedure, so as to improve the monitoring accuracy of Hg2+ and ensure the simultaneous measurement of Hg0, Hg2+, and Hgp in 2 h time resolution. We deployed the CSAMS in urban Beijing in September 2021 and observed an unprecedented elevated Hg2+ during the daytime with an average amplitude of 510 pg m-3. Using a zero-dimensional box model, the elevated Hg2+ production rate was attributed to high atmospheric oxidant concentrations, Hg0 heterogeneous and interfacial oxidation processes on the surface of atmospheric particles, or potential unknown oxidants.
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Affiliation(s)
- Yi Tang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Shuxiao Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Guoliang Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Deming Han
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Kaiyun Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Zhijian Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Qingru Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
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9
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Gačnik J, Živković I, Ribeiro Guevara S, Kotnik J, Berisha S, Vijayakumaran Nair S, Jurov A, Cvelbar U, Horvat M. Calibration Approach for Gaseous Oxidized Mercury Based on Nonthermal Plasma Oxidation of Elemental Mercury. Anal Chem 2022; 94:8234-8240. [PMID: 35647905 PMCID: PMC9201811 DOI: 10.1021/acs.analchem.2c00260] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Atmospheric mercury
measurements carried out in the recent decades
have been a subject of bias largely due to insufficient consideration
of metrological traceability and associated measurement uncertainty,
which are ultimately needed for the demonstration of comparability
of the measurement results. This is particularly challenging for gaseous
HgII species, which are reactive and their ambient concentrations
are very low, causing difficulties in proper sampling and calibration.
Calibration for atmospheric HgII exists, but barriers to
reliable calibration are most evident at ambient HgII concentration
levels. We present a calibration of HgII species based
on nonthermal plasma oxidation of Hg0 to HgII. Hg0 was produced by quantitative reduction of HgII in aqueous solution by SnCl2 and aeration. The
generated Hg0 in a stream of He and traces of reaction
gas (O2, Cl2, or Br2) was then oxidized
to different HgII species by nonthermal plasma. A highly
sensitive 197Hg radiotracer was used to evaluate the oxidation
efficiency. Nonthermal plasma oxidation efficiencies with corresponding
expanded standard uncertainty values were 100.5 ± 4.7% (k = 2) for 100 pg of HgO, 96.8 ± 7.3% (k = 2) for 250 pg of HgCl2, and 77.3 ± 9.4% (k = 2) for 250 pg of HgBr2. The presence of HgO,
HgCl2, and HgBr2 was confirmed by temperature-programmed
desorption quadrupole mass spectrometry (TPD-QMS). This work demonstrates
the potential for nonthermal plasma oxidation to generate reliable
and repeatable amounts of HgII compounds for routine calibration
of ambient air measurement instrumentation.
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Affiliation(s)
- Jan Gačnik
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia.,Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Sergio Ribeiro Guevara
- Laboratorio de Análisis por Activación Neutrónica, Centro Atómico Bariloche, Av. Bustillo km 9.5, 8400 Bariloche, Argentina
| | - Jože Kotnik
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia.,Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Sabina Berisha
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Sreekanth Vijayakumaran Nair
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia.,Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Andrea Jurov
- Department of Gaseous Electronics, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Uroš Cvelbar
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia.,Department of Gaseous Electronics, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Milena Horvat
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia.,Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia
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10
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Angot H, Rutkowski E, Sargent M, Wofsy SC, Hutyra LR, Howard D, Obrist D, Selin NE. Atmospheric mercury sources in a coastal-urban environment: a case study in Boston, Massachusetts, USA. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1914-1929. [PMID: 34739015 DOI: 10.1039/d1em00253h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Mercury (Hg) is an environmental toxicant dangerous to human health and the environment. Its anthropogenic emissions are regulated by global, regional, and local policies. Here, we investigate Hg sources in the coastal city of Boston, the third largest metropolitan area in the Northeastern United States. With a median of 1.37 ng m-3, atmospheric Hg concentrations measured from August 2017 to April 2019 were at the low end of the range reported in the Northern Hemisphere and in the range reported at North American rural sites. Despite relatively low ambient Hg concentrations, we estimate anthropogenic emissions to be 3-7 times higher than in current emission inventories using a measurement-model framework, suggesting an underestimation of small point and/or nonpoint emissions. We also test the hypothesis that a legacy Hg source from the ocean contributes to atmospheric Hg concentrations in the study area; legacy emissions (recycling of previously deposited Hg) account for ∼60% of Hg emitted annually worldwide (and much of this recycling takes place through the oceans). We find that elevated concentrations observed during easterly oceanic winds can be fully explained by low wind speeds and recirculating air allowing for accumulation of land-based emissions. This study suggests that the influence of nonpoint land-based emissions may be comparable in size to point sources in some regions and highlights the benefits of further top-down studies in other areas.
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Affiliation(s)
- Hélène Angot
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Extreme Environments Research Laboratory, École Polytechnique Fédérale de Lausanne (EPFL) Valais, Wallis, Sion, Switzerland
| | - Emma Rutkowski
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Maryann Sargent
- School of Engineering and Applied Science, Harvard University, Cambridge, MA, USA
| | - Steven C Wofsy
- School of Engineering and Applied Science, Harvard University, Cambridge, MA, USA
| | - Lucy R Hutyra
- Department of Earth and Environment, Boston University, Boston, MA, USA
| | - Dean Howard
- Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts-Lowell, MA, USA
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Daniel Obrist
- Department of Environmental, Earth, and Atmospheric Sciences, University of Massachusetts-Lowell, MA, USA
| | - Noelle E Selin
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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11
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Gačnik J, Živković I, Ribeiro Guevara S, Jaćimović R, Kotnik J, Horvat M. Validating an Evaporative Calibrator for Gaseous Oxidized Mercury. SENSORS 2021; 21:s21072501. [PMID: 33916694 PMCID: PMC8038396 DOI: 10.3390/s21072501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 11/20/2022]
Abstract
Understanding atmospheric mercury chemistry is the key for explaining the biogeochemical cycle of mercury and for improving the predictive capability of computational models. Increased efforts are being made to ensure comparable Hg speciation measurements in the air through establishing metrological traceability. While traceability for elemental mercury has been recently set, this is by no means the case for gaseous oxidized mercury (GOM). Since a calibration unit suitable for traceable GOM calibrations based on evaporation of HgCl2 solution was recently developed, the purpose of our work was to extensively evaluate its performance. A highly specific and sensitive 197Hg radiotracer was used for validation over a wide range of concentrations. By comparing experimental and calculated values, we obtained recoveries for the calibration unit. The average recoveries ranged from 88.5% for 1178 ng m−3 HgCl2 gas concentration to 39.4% for 5.90 ng m−3 HgCl2 gas concentration. The losses were due to the adsorption of oxidized Hg on the inner walls of the calibrator and tubing. An adsorption isotherm was applied to estimate adsorption enthalpy (ΔHads); a ΔHads value of −12.33 kJ mol−1 was obtained, suggesting exothermal adsorption. The results of the calibrator performance evaluation suggest that a newly developed calibration unit is only suitable for concentrations of HgCl2 higher than 1 µg m−3. The concentration dependence of recoveries prevents the system from being used for calibration of instruments for ambient GOM measurements. Moreover, the previously assessed uncertainty of this unit at µg m−3 level (2.0%, k = 2) was re-evaluated by including uncertainty related to recovery and was found to be 4.1%, k = 2. Calibrator performance was also evaluated for HgBr2 gas calibration; the recoveries were much lower for HgBr2 gas than for HgCl2 gas even at a high HgBr2 gas concentration (>1 µg m−3). As HgBr2 is often used as a proxy for various atmospheric HgBr species, the suitability of the unit for such calibration must be further developed.
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Affiliation(s)
- Jan Gačnik
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia;
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (I.Ž.); (R.J.); (J.K.)
| | - Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (I.Ž.); (R.J.); (J.K.)
| | - Sergio Ribeiro Guevara
- Laboratorio de Análisis por Activación Neutrónica, Centro Atómico Bariloche, Av. Bustillo km 9.5, Bariloche 8400, Argentina;
| | - Radojko Jaćimović
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (I.Ž.); (R.J.); (J.K.)
| | - Jože Kotnik
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (I.Ž.); (R.J.); (J.K.)
| | - Milena Horvat
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia;
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (I.Ž.); (R.J.); (J.K.)
- Correspondence: ; Tel.: +386-1-588-53-55
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12
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Miller MB, Howard DA, Pierce AM, Cook KR, Keywood M, Powell J, Gustin MS, Edwards GC. Atmospheric reactive mercury concentrations in coastal Australia and the Southern Ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 751:141681. [PMID: 32861947 DOI: 10.1016/j.scitotenv.2020.141681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 08/11/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Mercury (Hg), especially reactive Hg (RM), data from the Southern Hemisphere (SH) are limited. In this study, long-term measurements of both gaseous elemental Hg (GEM) and RM were made at two ground-based monitoring locations in Australia, the Cape Grim Baseline Air Pollution Station (CGBAPS) in Tasmania, and the Macquarie University Automatic Weather Station (MQAWS) in Sydney, New South Wales. Measurements were also made on board the Australian RV Investigator (RVI) during an ocean research voyage to the East Antarctic coast. GEM was measured using the standard Tekran® 2537 series analytical platform, and RM was measured using cation exchange membranes (CEM) in a filter-based sampling method. Overall mean RM concentrations at CGBAPS and MQAWS were 15.9 ± 6.7 pg m-3 and 17.8 ± 6.6 pg m-3, respectively. For the 10-week austral summer period on RVI, mean RM was 23.5 ± 6.7 pg m-3. RM concentrations at CGBAPS were seasonally invariable, while those at MQAWS were significantly different between summer and winter due to seasonal changes in synoptic wind patterns. During the RVI voyage, RM concentrations were relatively enhanced along the Antarctic coast (up to 30 pg m-3) and GEM concentrations were variable (0.2 to 0.9 ng m-3), suggesting periods of enrichment and depletion. Both RM and GEM concentrations were relatively lower while transiting the Southern Ocean farther north of Antarctica. RM concentrations measured in this study were higher in comparison to most other reported measurements of RM in the global marine boundary layer (MBL), especially for remote SH locations. As observations of GEM and RM concentrations inform global ocean-atmosphere model simulations of the atmospheric Hg budget, our results have important implications for understanding of total atmospheric Hg (TAM).
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Affiliation(s)
- Matthieu B Miller
- Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2113, Australia.
| | - Dean A Howard
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO 80303, United States
| | - Ashley M Pierce
- Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2113, Australia
| | - Kellie R Cook
- Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2113, Australia
| | - Melita Keywood
- Centre for Australian Climate and Weather Research, Australian Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
| | - Jennifer Powell
- Centre for Australian Climate and Weather Research, Australian Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
| | - Mae S Gustin
- Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV 89557, United States
| | - Grant C Edwards
- Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2113, Australia
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Abstract
This review focuses on providing the history of measurement efforts to quantify and characterize the compounds of reactive mercury (RM), and the current status of measurement methods and knowledge. RM collectively represents gaseous oxidized mercury (GOM) and that bound to particles. The presence of RM was first recognized through measurement of coal-fired power plant emissions. Once discovered, researchers focused on developing methods for measuring RM in ambient air. First, tubular KCl-coated denuders were used for stack gas measurements, followed by mist chambers and annular denuders for ambient air measurements. For ~15 years, thermal desorption of an annular KCl denuder in the Tekran® speciation system was thought to be the gold standard for ambient GOM measurements. Research over the past ~10 years has shown that the KCl denuder does not collect GOM compounds with equal efficiency, and there are interferences with collection. Using a membrane-based system and an automated system—the Detector for Oxidized mercury System (DOHGS)—concentrations measured with the KCl denuder in the Tekran speciation system underestimate GOM concentrations by 1.3 to 13 times. Using nylon membranes it has been demonstrated that GOM/RM chemistry varies across space and time, and that this depends on the oxidant chemistry of the air. Future work should focus on development of better surfaces for collecting GOM/RM compounds, analytical methods to characterize GOM/RM chemistry, and high-resolution, calibrated measurement systems.
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14
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Lyman SN, Gratz LE, Dunham-Cheatham SM, Gustin MS, Luippold A. Improvements to the Accuracy of Atmospheric Oxidized Mercury Measurements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13379-13388. [PMID: 33075225 DOI: 10.1021/acs.est.0c02747] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We developed a cation-exchange membrane-based dual-channel system to measure elemental and oxidized mercury and deployed it with an automated calibration system and the University of Nevada, Reno-Reactive Mercury Active System (UNR-RMAS) at a rural/suburban field site in Colorado during the summer of 2018. Unlike oxidized mercury measurements collected via the widely used KCl denuder method, the dual-channel system was able to quantitatively recover HgCl2 and HgBr2 injected by the calibrator into the ambient sample air and compared well with the UNR-RMAS measurements. The system measured at 10 min intervals and had a 3-h average detection limit for oxidized mercury of 33 pg m-3. It was able to detect day-to-day variability and diel cycles in oxidized mercury (0 to 200 pg m-3) and will be an important tool for future studies of atmospheric mercury. We used a gravimetric method to independently determine the total mercury permeation rate from the permeation tubes. Permeation rates derived from the gravimetric method matched the permeation rates observed via mercury measurement devices to within 25% when the mercury permeation rate was relatively high (up to 30 pg s-1), but the agreement decreased for lower permeation rates, probably because of increased uncertainty in the gravimetric measurements.
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Affiliation(s)
- Seth N Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0305, United States
| | - Lynne E Gratz
- Environmental Studies Program, Colorado College, Colorado Springs, Colorado 80903-3298, United States
| | - Sarrah M Dunham-Cheatham
- Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, Nevada 89557, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, Nevada 89557, United States
| | - Adriel Luippold
- Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, Nevada 89557, United States
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Gustin MS, Bank MS, Bishop K, Bowman K, Branfireun B, Chételat J, Eckley CS, Hammerschmidt CR, Lamborg C, Lyman S, Martínez-Cortizas A, Sommar J, Tsui MTK, Zhang T. Mercury biogeochemical cycling: A synthesis of recent scientific advances. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:139619. [PMID: 32783819 PMCID: PMC7430064 DOI: 10.1016/j.scitotenv.2020.139619] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 05/23/2023]
Abstract
The focus of this paper is to briefly discuss the major advances in scientific thinking regarding: a) processes governing the fate and transport of mercury in the environment; b) advances in measurement methods; and c) how these advances in knowledge fit in within the context of the Minamata Convention on Mercury. Details regarding the information summarized here can be found in the papers associated with this Virtual Special Issue of STOTEN.
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Affiliation(s)
- Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89439, USA.
| | - Michael S Bank
- Department of Contaminants and Biohazards, Institute of Marine Research, Bergen, Norway; Department of Environmental Conservation, University of Massachusetts, Amherst, MA 01255, USA
| | - Kevin Bishop
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, 75007 Uppsala, Sweden
| | - Katlin Bowman
- Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA; University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Brian Branfireun
- Department of Biology and Centre for Environment and Sustainability, Western University, London, Canada
| | - John Chételat
- Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, ON K1A 0H3, Canada
| | - Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101, USA
| | - Chad R Hammerschmidt
- Wright State University, Department of Earth and Environmental Sciences, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Carl Lamborg
- University of California Santa Cruz, Ocean Sciences Department, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Seth Lyman
- Bingham Research Center, Utah State University, 320 N Aggie Blvd., Vernal, UT, USA
| | - Antonio Martínez-Cortizas
- EcoPast (GI-1553), Facultade de Bioloxía, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Jonas Sommar
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Martin Tsz-Ki Tsui
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Tong Zhang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China
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Luippold A, Gustin MS, Dunham-Cheatham SM, Castro M, Luke W, Lyman S, Zhang L. Use of Multiple Lines of Evidence to Understand Reactive Mercury Concentrations and Chemistry in Hawai'i, Nevada, Maryland, and Utah, USA. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7922-7931. [PMID: 32506903 DOI: 10.1021/acs.est.0c02283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
To advance our understanding of the mercury (Hg) biogeochemical cycle, concentrations and chemistry of gaseous oxidized Hg (GOM), particulate-bound Hg (PBM), and reactive Hg (RM = GOM + PBM) need to be known. The UNR-RMAS 2.0 provides a solution that will advance knowledge. From 11/2017 to 02/2019, the RMAS 2.0 was deployed in Hawai'i, Nevada, Maryland, and Utah to test system performance and develop an understanding of RM at locations impacted by different atmospheric oxidants. Mauna Loa Observatory, Hawai'i, impacted by the free troposphere and the marine boundary layer, had primarily -Br/Cl RM compounds. The Nevada location, directly adjacent to a major interstate highway and experiences inputs from the free troposphere, exhibited -Br/Cl, -N, -S, and organic compounds. In Maryland, compounds observed were -N, -S, and organic-Hg. This site is downwind of coal-fired power plants and located in a forested area. The location in Utah is in a basin impacted by oil and natural gas extraction, multiday wintertime inversion episodes, and inputs from the free troposphere. Compounds were -Br/Cl or -O, -N, and -Br/Cl. The chemical forms of RM identified were consistent with the air source areas, predominant ion chemistry, criterion air pollutants, and meteorology.
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Affiliation(s)
- Adriel Luippold
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Sarrah M Dunham-Cheatham
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada 89557, United States
| | - Mark Castro
- Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, Maryland 21532, United States
| | - Winston Luke
- Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, Maryland 20740, United States
| | - Seth Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84322, United States
| | - Lei Zhang
- School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China
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17
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Wang X, Yuan W, Lin CJ, Luo J, Wang F, Feng X, Fu X, Liu C. Underestimated Sink of Atmospheric Mercury in a Deglaciated Forest Chronosequence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8083-8093. [PMID: 32510932 DOI: 10.1021/acs.est.0c01667] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Mercury (Hg) deposition through litterfall has been regarded as the main input of gaseous elemental mercury (Hg0) into forest ecosystems. We hypothesize that earlier studies largely underestimated this sink because the contribution of Hg0 uptake by moss and the downward transport to wood and throughfall is overlooked. To test the hypothesis, we investigated the Hg fluxes contributed via litterfall and throughfall, Hg pool sizes in moss covers and woody biomass as well as their isotopic signatures in a glacier-to-forest succession ecosystem of the Southeast Tibetan Plateau. Results show that Hg0 depositional uptake and pool sizes stored in moss and woody biomass increase rapidly with the time after glacier retreat. Using the flux data as input to a Hg isotopic mixing model, Hg deposition through litterfall accounts for 27-85% of the total accumulation rate of Hg0 in organic soils of glacial retreat over 20-90 years, revealing the presence of additional sources of Hg0 input. Atmospheric Hg0 accounts for 76 ± 24% in ground moss, 86 ± 15% in tree moss, 62-92% in above ground woody biomass (branch-bark-stem), and 44-83% in roots. The downward decreasing gradient of atmospheric Hg0 fractions from the above ground woody biomass to roots suggests a foliage-to-root Hg transport in vegetation after uptake. Additionally, 34-82% of atmospheric Hg0 in throughfall further amplifies the accumulation of Hg0 from atmospheric sources. We conclude that woody biomass, moss, and throughfall represent important Hg0 sinks in forest ecosystems. These previously unaccounted for sink terms significantly increase the previously estimated atmospheric Hg0 sink via litterfall.
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Affiliation(s)
- Xun Wang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Wei Yuan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Che-Jen Lin
- Center for Advances in Water and Air Quality, Lamar University, Beaumont, Texas 77710, United States
- Department of Civil and Environmental Engineering, Lamar University, Beaumont, Texas 77710, United States
| | - Ji Luo
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu 610041, China
| | - Feiyue Wang
- Centre for Earth Observation Science, and Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
- Center for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences, Xian 710061, China
| | - Chen Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
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18
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Tang H, You W, Wang Z, Li C, Zhu C, Cai L, Duan Y. Detrimental effects of SO 2 on gaseous mercury(II) adsorption and retention by CaO-based sorbent traps: Competition and heterogeneous reduction. JOURNAL OF HAZARDOUS MATERIALS 2020; 387:121679. [PMID: 31796365 DOI: 10.1016/j.jhazmat.2019.121679] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/15/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Reliable gaseous Hg(II) measurement is crucial to mercury emissions control from coal-fired flue gas, but Hg(II) sampling under SO2 condition could probably increase the uncertainty of sorbent traps. CaO-AcS synthesized from calcium acetate and porous support were previously demonstrated to be effective for Hg(II) trapping under SO2-free condition. This work further evaluated SO2 influence on its Hg(II) retention ability via integrating experimental and DFT computational studies. Increased breakthrough rate of HgCl2 was found in a two-section CaO-AcS trap under SO2 conditions. Significant basicity and porosity loss of CaO-AcS were attributed to the formation of agglomerate CaSO3. Hg0 release from CaO-AcS samples suggested potential reactions between Hg(II) and SO2. The detected HgO and Hg2SO4 species by Hg-TPD in CaO-AcS further confirmed this speculation. Moreover, both competition and reduction effects of SO2 on surface-bound Hg(II) species were substantiated by DFT calculations. SO2 showed a stronger interaction with CaO than HgCl2 because SO2 has a lower LUMO level and can accept electrons easier. Reaction pathways indicated Hg(II) was partially reduced to Hg2SO4 under SO2-deficient condition, or directly reduced to Hg0 under SO2-rich condition. This work fully proposed the SO2 influence mechanisms and improvement countermeasures for practical gaseous Hg(II) sampling.
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Affiliation(s)
- Hongjian Tang
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China; Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576, Singapore
| | - Wenqin You
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States
| | - Zewei Wang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States
| | - Chunfeng Li
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Chun Zhu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Liang Cai
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Yufeng Duan
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu, 210096, China.
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Lyman SN, Cheng I, Gratz LE, Weiss-Penzias P, Zhang L. An updated review of atmospheric mercury. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:135575. [PMID: 31784172 DOI: 10.1016/j.scitotenv.2019.135575] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
The atmosphere is a key component of the biogeochemical cycle of mercury, acting as a reservoir, transport mechanism, and facilitator of chemical reactions. The chemical and physical behavior of atmospheric mercury determines how, when, and where emitted mercury pollution impacts ecosystems. In this review, we provide current information about what is known and what remains uncertain regarding mercury in the atmosphere. We discuss new ambient, laboratory, and theoretical information about the chemistry of mercury in various atmospheric media. We review what is known about mercury in and on solid- and liquid-phase aerosols. We present recent findings related to wet and dry deposition and spatial and temporal trends in atmospheric mercury concentrations. We also review atmospheric measurement methods that are in wide use and those that are currently under development.
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Affiliation(s)
- Seth N Lyman
- Bingham Research Center, Utah State University, 320 N Aggie Blvd., Vernal, UT, USA; Department of Chemistry and Biochemistry, Utah State University, 4820 Old Main Hill, Logan, UT, USA.
| | - Irene Cheng
- Air Quality Research Division, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, Ontario, Canada
| | - Lynne E Gratz
- Environmental Studies Program, Colorado College, 14 East Cache la Poudre St., Colorado Springs, CO, USA
| | - Peter Weiss-Penzias
- Chemistry and Biochemistry Department, University of California, Santa Cruz, 1156 High St, Santa Cruz, CA, USA; Microbiology and Environmental Toxicology Department, University of California, Santa Cruz, 1156 High St, Santa Cruz, CA, USA
| | - Leiming Zhang
- Air Quality Research Division, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, Ontario, Canada
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20
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Gustin MS, Dunham-Cheatham SM, Zhang L. Comparison of 4 Methods for Measurement of Reactive, Gaseous Oxidized, and Particulate Bound Mercury. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14489-14495. [PMID: 31742397 DOI: 10.1021/acs.est.9b04648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The atmosphere is an important (1) pathway by which mercury (Hg) is transported around the globe and (2) source of Hg to ecosystems. Thus, understanding Hg atmospheric chemistry is critical for understanding the biogeochemical cycle and impacts to human and ecosystem health. Work over the past 13 years has demonstrated that the standard instrument used to measure atmospheric Hg does not accurately quantify gaseous oxidized mercury (GOM) or particulate bound mercury (PBM). This study focused on comparing four methods for quantifying atmospheric Hg and identifying Hg(II) compounds. Data from two automated systems, the Tekran 2537/1130 system and the University of Nevada, Reno-Dual Channel System (DCS), were compared with two University of Nevada, Reno-Reactive Mercury Active Systems (RMAS 2.0). One RMAS 2.0 included cation exchange membranes (CEMs) and nylon membranes, and the second included a polytetrafluoroethylene (PTFE) membrane upstream of the CEM and nylon membranes. The Tekran system and the DCS underestimated GOM concentrations with respect to that measured using the RMAS 2.0. The RMAS 2.0 with the upstream PTFE provided a means of distinguishing GOM and PBM. Thermal desorption of nylon membrane data identified a variety of GOM and PBM compounds present.
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Affiliation(s)
- Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science , University of Nevada, Reno , Reno , Nevada 89557 , United States
| | - Sarrah M Dunham-Cheatham
- Department of Natural Resources and Environmental Science , University of Nevada, Reno , Reno , Nevada 89557 , United States
| | - Lei Zhang
- School of the Environment , Nanjing University , Nanjing , Jiangsu 210023 , China
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21
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Liu C, Fu X, Zhang H, Ming L, Xu H, Zhang L, Feng X. Sources and outflows of atmospheric mercury at Mt. Changbai, northeastern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 663:275-284. [PMID: 30711594 DOI: 10.1016/j.scitotenv.2019.01.332] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
Atmospheric gaseous elemental mercury (GEM), particulate bound mercury (PBM), and gaseous oxidized mercury (GOM) were continuously measured at a remote site in northeastern China from July 2013 to July 2014. Mean (±1SD) concentrations of the hourly data of GEM, PBM, and GOM were 1.68 ± 0.47 ng m-3, 16.6 ± 15.2 pg m-3, and 5.4 ± 6.4 pg m-3, respectively. Concentration-weighted trajectory (CWT) analysis suggested that the potential source regions of GEM and GOM observed at this site were northern and eastern China. GEM and GOM CWT values significantly correlated with anthropogenic Hg emissions, suggesting that long-range transport of anthropogenic Hg emissions played an important role in GEM and GOM pollutions in remote areas of northeastern China. On the other hand, long-range transport of anthropogenic PBM emissions from eastern and northeastern China combined with large-scale biomass burning in Northeast Asia likely dominated PBM pollution. Principal component analysis (PCA) results, making use of the combined data sets of speciated atmospheric Hg, trace elements, and meteorological parameters, suggested that coal combustion and non-ferrous metal smelting contributed significantly to all the Hg species at this site, while the other anthropogenic sources in China also had a major impact on GEM. Forward air mass trajectory analysis revealed that outflows of GEM from northeastern China may have a potential impact on GEM pollutions in remote and oceanic areas in Northeast Asia.
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Affiliation(s)
- Chen Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
| | - Xuewu Fu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
| | - Hui Zhang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
| | - Lili Ming
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Hao Xu
- Open Research Station of Changbai Mountain Forest Ecosystems, Institute of Applied Ecology, Chinese Academy of Sciences, Yanbian 133613, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario, Canada
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
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Tang H, Li C, Duan Y, Zhu C, Cai L. Combined experimental and theoretical studies on adsorption mechanisms of gaseous mercury(II) by calcium-based sorbents: The effect of unsaturated oxygen sites. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 656:937-945. [PMID: 30625679 DOI: 10.1016/j.scitotenv.2018.11.460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/24/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
Accurate mercury speciation measurements are critical for developing methods for mercury removal from flue gas, but the lack of reliable adsorbents has made Hg2+ selective retention challenging. Calcium oxide (CaO) loaded on porous support is promising for HgCl2 selective adsorption because of its porosity and alkaline nature. The main hypothesis investigated in this paper is if the capacity of CaO sorbent for HgCl2 selective adsorption is attributed to its basic sites, then this will be drastically impacted by the calcium precursors. We synthesized a suite of CaO/SiO2 sorbents from different precursors, including hydrated calcium oxide (CaO-HS), calcium nitrate tetrahydrate (CaO-NS), and calcium acetate monohydrate (CaO-AcS), to investigate their performance on HgCl2 selective adsorption in a fixed-bed reactor. Compared with CaO-HS and CaO-NS, CaO-AcS was demonstrated to have the strongest affinity for HgCl2 and almost complete breakthrough for Hg0. Advanced porosity and surface basicity of CaO-AcS were confirmed by characterization analysis. CaO (001) and CaO (011) facet as well as surface defects that have different unsaturated O sites were observed using the high resolution transmission electron microscope (HRTEM). Combined theoretical and experimental methods were used to study the interaction mechanisms between HgCl2 and basic sites on CaO-AcS surfaces. Density functional theory (DFT) calculations indicated all CaO surfaces weakly interact with Hg0, while four robust bonding states of HgCl2 were predicted on different basic sites with the intensity in increasing order: Monodentate < Tridendate < Bidentate < Bridging. This was consistent with HgCl2-TPD experiments that demonstrated that the four HgCl2 adsorption configurations on CaO-AcS were attributed to different unsaturated O sites. The findings in this work highlight the application potential of CaO-AcS for gaseous Hg2+ sampling and measurement from coal-fired flue gas.
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Affiliation(s)
- Hongjian Tang
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
| | - Chunfeng Li
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yufeng Duan
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China.
| | - Chun Zhu
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
| | - Liang Cai
- Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China
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Wang Z, Sun T, Driscoll CT, Yin Y, Zhang X. Mechanism of Accumulation of Methylmercury in Rice ( Oryza sativa L.) in a Mercury Mining Area. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:9749-9757. [PMID: 30129363 DOI: 10.1021/acs.est.8b01783] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Rice consumption is the primary pathway for methylmercury (MeHg) exposure at inland mercury (Hg) mining areas of China. The sources and processes of formation and translocation for MeHg in rice plant are complex and remain largely unknown. In this study, rice ( Oryza sativa L.) was exposed to isotopically labeled dimethylmercury (DMe199Hg) in field experiments using open top chambers to explore the response of MeHg accumulation in rice tissues to different levels of DMe199Hg in air. Rice leaves assimilated DMeHg from air, which was subsequently largely stored in aboveground tissues, including the rice grain, with only a small amount reaching the root. Combining these experimental results with field investigations of DMeHg concentrations in air beneath the rice canopy in a Hg mining area, we estimate that 15.5%, 10.8%, and 8.50% MeHg in the brown rice, the leaf, and the upper stalk, respectively, could be derived from atmospheric sources of DMeHg, while 99.5% of MeHg in rice root originated from the rice soil-water system. These findings help refine the mechanism of MeHg accumulation in rice that, in addition to soil, a fraction of MeHg in rice plants can be derived from DMeHg emissions from flooded rice paddies in Hg mining areas.
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Affiliation(s)
- Zhangwei Wang
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Ting Sun
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering , Syracuse University , 151 Link Hall , Syracuse , New York 13244 , United States
| | - Yongguang Yin
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiaoshan Zhang
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , No. 18 Shuangqing Road , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
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24
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Effect of temperature on chlorine dioxide inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on spinach, tomatoes, stainless steel, and glass surfaces. Int J Food Microbiol 2018; 275:39-45. [PMID: 29627661 DOI: 10.1016/j.ijfoodmicro.2018.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/05/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022]
Abstract
The objective of this study was to evaluate how treatment temperature influences the solubility of ClO2 gas and the antimicrobial effect of ClO2 gas against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on produce and food contact surfaces. Produce and food contact surfaces inoculated with a combined culture cocktail of three strains each of the three foodborne pathogens were processed in a treatment chamber with 20 ppmv ClO2 gas at 15 or 25 °C under the same conditions of absolute humidity (11.2-12.3 g/m3) for up to 30 min. As treatment time increased, ClO2 gas treatment at 15 °C caused significantly more (p < 0.05) inactivation of the three pathogens than treatment at 25 °C. ClO2 gas treatment at 25 °C for 30 min resulted in 1.15 to 1.54, 1.53 to 1.88, and 1.00 to 1.78 log reductions of the three pathogens on spinach leaves, tomatoes, and stainless steel No.4, respectively. ClO2 gas treatment at 15 °C for 30 min caused 2.53 to 2.88, 2.82 to 3.23, and 2.37 to 3.03 log reductions of the three pathogens on spinach leaves, tomatoes, and stainless steel No.4, respectively. Treatment with ClO2 gas at 25 °C for 20 min resulted in 1.88 to 2.31 log reductions of the three pathogens on glass while >5.91 to 6.82 log reductions of these pathogens occurred after 20 min when treated at 15 °C. Residual ClO2 levels after gas treatment at 15 °C were significantly (p < 0.05) higher than those at 25 °C. The results of this study can help the food processing industry establish optimum ClO2 gas treatment conditions for maximizing the antimicrobial efficacy of ClO2 gas.
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25
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Pierce AM, Gustin MS, Christensen JN, Loría-Salazar SM. Use of multiple tools including lead isotopes to decipher sources of ozone and reactive mercury to urban and rural locations in Nevada, USA. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 615:1411-1427. [PMID: 29751446 DOI: 10.1016/j.scitotenv.2017.08.284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 06/08/2023]
Abstract
Ambient air particulate matter (<2.5μm in diameter) samples were collected on two different filter types in 2014 and 2015 over 24h periods and analyzed for reactive mercury (gaseous oxidized mercury+particulate bound mercury) concentrations and lead isotopes to determine sources of pollution to three sites in Nevada, USA. Two sites were located on the western edge of Nevada (Reno, urban, 1370m and Peavine Peak, rural, high elevation, 2515m); the third location was ~485km east in rural Great Basin National Park, NV (2061m). Reactive mercury samples were collected on cation exchange membranes simultaneously with lead samples, collected on Teflon membranes. Lead isotopic ratios have previously identified trans-Pacific lead sources based on the 206/207 and 208/207 lead ratios. Influence from trans-Pacific air masses was higher from March to June associated with long-range transport of pollutants. Spring months are well known for increased transport across the Pacific; however, fall months were also influenced by trans-Pacific air masses in this study. Western North American background ozone concentrations have been measured and modeled at 50 to 55ppbv. Median ozone concentrations at both rural sites in Nevada were within this range. Sources leading to enhancements in ozone of 2 to 18ppbv above monthly medians in Nevada included emissions from Eurasia, regional urban centers, and global and regional wildfires, resulting in concentrations close to the USA air quality standard. At the high elevation locations, ozone was derived from pollutants being transported in the free troposphere that originate around the globe; however, Eurasia and Asia were dominant sources to the Western USA. Negative correlations between reactive mercury and percent Asian lead, Northern Eurasia and East Asia trajectories indicated reactive mercury concentrations at the two high elevation sites were produced by oxidants from local, regional, and marine boundary layer sources.
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Affiliation(s)
- Ashley M Pierce
- Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV 89557, USA.
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV 89557, USA.
| | - John N Christensen
- Energy Geosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - S Marcela Loría-Salazar
- Atmospheric Science Program, Department of Physics, University of Nevada, Reno, NV 89557, USA
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26
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Arnold J, Gustin MS, Weisberg PJ. Evidence for Nonstomatal Uptake of Hg by Aspen and Translocation of Hg from Foliage to Tree Rings in Austrian Pine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1174-1182. [PMID: 29232509 DOI: 10.1021/acs.est.7b04468] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
To determine whether trees are reliable biomonitors of air mercury (Hg) pollution concentrations were measured in bark, foliage, and tree rings. Data were developed using 4-year old Pinus and Populus trees grown from common genetic stock in Oregon and subsequently transferred to four air treatments differing in gaseous oxidized mercury (GOM) chemistry and total gaseous Hg (TGM) concentrations. Soil of a subset of trees was spiked with HgBr2 in solution to test for root uptake. Results indicate no significant effect of the soil spike or GOM compounds on tree tissue Hg concentrations. TGM treatment had a significant effect on Pinus and Populus foliage, and Pinus year 5 growth ring concentrations. Populus foliar Hg concentrations were highest in the exposure where 24 h TGM concentrations were highest, indicating the importance of the nonstomatal pathway for uptake. Pinus tree ring concentrations were correlated to day time TGM concentrations suggesting Hg accumulation into tree rings is by way of the stomata and subsequent translocation by way of phloem. Populus leaves and Pinus rings can be used as biomonitors for TGM concentrations over space. However, the use of trees as temporal proxies requires further investigation due to radial translocation observed in active sapwood tree rings.
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Affiliation(s)
- Jennifer Arnold
- Department of Natural Resources and Environmental Science University of Nevada-Reno Reno, Nevada 89557, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science University of Nevada-Reno Reno, Nevada 89557, United States
| | - Peter J Weisberg
- Department of Natural Resources and Environmental Science University of Nevada-Reno Reno, Nevada 89557, United States
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27
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Jiao Y, Dibble TS. First kinetic study of the atmospherically important reactions BrHg˙ + NO 2 and BrHg˙ + HOO. Phys Chem Chem Phys 2018; 19:1826-1838. [PMID: 28000816 DOI: 10.1039/c6cp06276h] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We use computational chemistry to determine the rate constants and product yields for the reactions of BrHg˙ with the atmospherically abundant radicals NO2 and HOO. The reactants, products, and well-defined transition states are characterized using CCSD(T) with large basis sets. The potential energy profiles for the barrierless addition of HOO and NO2 to BrHg˙ are characterized using CASPT2 and RHF-CCSDT, and the rate constants are computed as a function of temperature and pressure using variational transition state theory and master equation simulations. The calculated rate constant for the addition of NO2 to BrHg˙ is larger than that for the addition of HOO by a factor of up to two under atmospheric conditions. For the reaction of HOO with BrHg˙ the addition reaction entirely dominates competing HOO + BrHg˙ reaction channels. The addition of NO2 to BrHg˙ initially produces both BrHgNO2 and BrHgONO, but after a few seconds under atmospheric conditions the sole product is syn-BrHgONO. A previously unsuspected reaction channel for BrHg˙ + NO2 competes with the addition to yield Hg + BrNO2. This reaction reduces the mercury oxidation state in BrHg˙ from Hg(i) to Hg(0) and slows the atmospheric oxidation of Hg(0). While the rate constant for this reduction channel is not well-constrained by the present calculations, it may be as much as 18% as large as the oxidation channel under some atmospheric conditions. As no experimental kinetic or product yield data are available for the reactions studied here, this work will provide guidance for atmospheric modelers and experimental kineticists.
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Affiliation(s)
- Yuge Jiao
- Department of Chemistry, State University of New York, College of Environmental Science and Forestry, 1 Forestry Dr, Syracuse, NY 13210, USA.
| | - Theodore S Dibble
- Department of Chemistry, State University of New York, College of Environmental Science and Forestry, 1 Forestry Dr, Syracuse, NY 13210, USA.
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28
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Marusczak N, Sonke JE, Fu X, Jiskra M. Tropospheric GOM at the Pic du Midi Observatory-Correcting Bias in Denuder Based Observations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:863-869. [PMID: 27960251 DOI: 10.1021/acs.est.6b04999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Gaseous elemental mercury (GEM, Hg) emissions are transformed to divalent reactive Hg (RM) forms throughout the troposphere and stratosphere. RM is often operationally quantified as the sum of particle bound Hg (PBM) and gaseous oxidized Hg (GOM). The measurement of GOM and PBM is challenging and under mounting criticism. Here we intercompare six months of automated GOM and PBM measurements using a Tekran (TK) KCl-coated denuder and quartz regenerable particulate filter method (GOMTK, PBMTK, and RMTK) with RMCEM collected on cation exchange membranes (CEMs) at the high altitude Pic du Midi Observatory. We find that RMTK is systematically lower by a factor of 1.3 than RMCEM. We observe a significant relationship between GOMTK (but not PBMTK) and Tekran flushTK blanks suggesting significant loss (36%) of labile GOMTK from the denuder or inlet. Adding the flushTK blank to RMTK results in good agreement with RMCEM (slope = 1.01, r2 = 0.90) suggesting we can correct bias in RMTK and GOMTK. We provide a bias corrected (*) Pic du Midi data set for 2012-2014 that shows GOM* and RM* levels in dry free tropospheric air of 198 ± 57 and 229 ± 58 pg m-3 which agree well with in-flight observed RM and with model based GOM and RM estimates.
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Affiliation(s)
- Nicolas Marusczak
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
| | - Jeroen E Sonke
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
| | - Xuewu Fu
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
| | - Martin Jiskra
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
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29
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Cheng I, Zhang L. Uncertainty Assessment of Gaseous Oxidized Mercury Measurements Collected by Atmospheric Mercury Network. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:855-862. [PMID: 28009168 DOI: 10.1021/acs.est.6b04926] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Gaseous oxidized mercury (GOM) measurement uncertainties undoubtedly impact the understanding of mercury biogeochemical cycling; however, there is a lack of consensus on the uncertainty magnitude. The numerical method presented in this study provides an alternative means of estimating the uncertainties of previous GOM measurements. Weekly GOM in ambient air was predicted from measured weekly mercury wet deposition using a scavenging ratio approach, and compared against field measurements of 2-4 hly GOM to estimate the measurement biases of the Tekran speciation instruments at 13 Atmospheric Mercury Network (AMNet) sites. Multiyear average GOM measurements were estimated to be biased low by more than a factor of 2 at six sites, between a factor of 1.5 and 1.8 at six other sites, and below a factor of 1.3 at one site. The differences between predicted and observed were significantly larger during summer than other seasons potentially because of higher ozone concentrations that may interfere with GOM sampling. The analysis data collected over six years at multiple sites suggests a systematic bias in GOM measurements, supporting the need for further investigation of measurement technologies and identifying the chemical composition of GOM.
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Affiliation(s)
- Irene Cheng
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario M3H 5T4 Canada
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Ontario M3H 5T4 Canada
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30
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Pierce AM, Gustin MS. Development of a Particulate Mass Measurement System for Quantification of Ambient Reactive Mercury. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:436-445. [PMID: 27966905 DOI: 10.1021/acs.est.6b04707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Teledyne Advanced Pollution Instrumentation (TAPI) model 602 BetaPlus particulate system provides nondestructive analysis of particulate matter (PM2.5) mass concentration. This instrument was used to determine if measurements made with cation exchange membranes (CEM) were comparable to standard methods, the β attenuation method at two locations in Reno, NV and an environmental β attenuation method and gravimetric method at Great Basin National Park, NV. TAPI PM2.5 CEM measurements were statistically similar to the other three PM2.5 methods. Once this was established, the second objective, a destructive method for measurement of reactive mercury (RM = gaseous oxidized and particulate bound Hg), was tested. Samples collected at 16.7 L per min (Lpm) for 24 h on CEM from the TAPI were compared to those measured by the University of Nevada, Reno-Reactive Mercury Active System (UNRRMAS, 1 Lpm) CEM and a Tekran 2537/1130/1135 system (7 Lpm). Given the use of CEM in the TAPI and UNRRMAS, we hypothesized that both should collect RM. Due to the high flow rate and different inlets, TAPI data were systematically lower than the UNRRMAS. Correlation between RM concentrations demonstrated that the TAPI may be used to estimate 24 h resolution RM concentrations in Nevada.
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Affiliation(s)
- Ashley M Pierce
- Department of Natural Resources and Environmental Sciences, University of Nevada , Reno, 1664 N. Virginia St. Reno, Nevada 89557, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Sciences, University of Nevada , Reno, 1664 N. Virginia St. Reno, Nevada 89557, United States
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31
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Lyman S, Jones C, O'Neil T, Allen T, Miller M, Gustin MS, Pierce AM, Luke W, Ren X, Kelley P. Automated Calibration of Atmospheric Oxidized Mercury Measurements. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12921-12927. [PMID: 27934266 DOI: 10.1021/acs.est.6b04211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The atmosphere is an important reservoir for mercury pollution, and understanding of oxidation processes is essential to elucidating the fate of atmospheric mercury. Several recent studies have shown that a low bias exists in a widely applied method for atmospheric oxidized mercury measurements. We developed an automated, permeation tube-based calibrator for elemental and oxidized mercury, and we integrated this calibrator with atmospheric mercury instrumentation (Tekran 2537/1130/1135 speciation systems) in Reno, Nevada and at Mauna Loa Observatory, Hawaii, U.S.A. While the calibrator has limitations, it was able to routinely inject stable amounts of HgCl2 and HgBr2 into atmospheric mercury measurement systems over periods of several months. In Reno, recovery of injected mercury compounds as gaseous oxidized mercury (as opposed to elemental mercury) decreased with increasing specific humidity, as has been shown in other studies, although this trend was not observed at Mauna Loa, likely due to differences in atmospheric chemistry at the two locations. Recovery of injected mercury compounds as oxidized mercury was greater in Mauna Loa than in Reno, and greater still for a cation-exchange membrane-based measurement system. These results show that routine calibration of atmospheric oxidized mercury measurements is both feasible and necessary.
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Affiliation(s)
- Seth Lyman
- Bingham Research Center, Utah State University , Vernal, Utah 84322, United States
| | - Colleen Jones
- Bingham Research Center, Utah State University , Vernal, Utah 84322, United States
| | - Trevor O'Neil
- Bingham Research Center, Utah State University , Vernal, Utah 84322, United States
| | - Tanner Allen
- Bingham Research Center, Utah State University , Vernal, Utah 84322, United States
| | - Matthieu Miller
- Macquarie University , North Ryde, New South Wales Australia
- Department of Natural Resources and Environmental Science, University of Nevada, Reno , Reno, Nevada 89557, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno , Reno, Nevada 89557, United States
| | - Ashley M Pierce
- Department of Natural Resources and Environmental Science, University of Nevada, Reno , Reno, Nevada 89557, United States
| | - Winston Luke
- Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, Maryland 20742, United States
| | - Xinrong Ren
- Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, Maryland 20742, United States
- Cooperative Institute for Climate and Satellites, University of Maryland , College park, Maryland 20742, United States
| | - Paul Kelley
- Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, Maryland 20742, United States
- Cooperative Institute for Climate and Satellites, University of Maryland , College park, Maryland 20742, United States
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32
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Sexauer Gustin M, Pierce AM, Huang J, Miller MB, Holmes HA, Loria-Salazar SM. Evidence for Different Reactive Hg Sources and Chemical Compounds at Adjacent Valley and High Elevation Locations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12225-12231. [PMID: 27801579 DOI: 10.1021/acs.est.6b03339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The spatial distribution of chemical compounds and concentration of reactive mercury (RM), defined as the sum of gaseous oxidized mercury (GOM) and <3 μm particulate bound mercury (PBM), are poorly characterized. The objective of this study was to understand the chemistry, concentration, and spatial and temporal distribution of GOM at adjacent locations (12 km apart) with a difference in elevation of ∼1000 m. Atmospheric GOM measurements were made with passive and active samplers using membranes, and at one location, a Tekran mercury measurement system was used. The chemistry of GOM varied across time and location. On the basis of data collected, chemistry at the low elevation site adjacent to a highway was primarily influenced by pollutants generated by mobile sources (GOM = nitrogen and sulfur-based compounds), and the high elevation site (GOM = halogen-based compounds) was affected by long-range transport in the free troposphere over the marine boundary layer into Nevada. Data collected at these two locations demonstrate that different GOM compounds exist depending on the oxidants present in the air. Measurements of GOM made by the KCl denuder in the Tekran instrument located at the low elevation site were lower than that measured using membranes by 1.7-13 times. Accurate measurements of atmospheric concentrations and chemistry of RM are necessary for proper assessment of environmental impacts, and field measurements are essential for atmospheric models, which in turn influence policy decisions.
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Affiliation(s)
- Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science and ‡Atmospheric Sciences Program, Department of Physics University of Nevada-Reno , Reno, Nevada 89557, United States
| | - Ashley M Pierce
- Department of Natural Resources and Environmental Science and ‡Atmospheric Sciences Program, Department of Physics University of Nevada-Reno , Reno, Nevada 89557, United States
| | - Jiaoyan Huang
- Department of Natural Resources and Environmental Science and ‡Atmospheric Sciences Program, Department of Physics University of Nevada-Reno , Reno, Nevada 89557, United States
| | - Matthieu B Miller
- Department of Natural Resources and Environmental Science and ‡Atmospheric Sciences Program, Department of Physics University of Nevada-Reno , Reno, Nevada 89557, United States
| | - Heather A Holmes
- Department of Natural Resources and Environmental Science and ‡Atmospheric Sciences Program, Department of Physics University of Nevada-Reno , Reno, Nevada 89557, United States
| | - S Marcela Loria-Salazar
- Department of Natural Resources and Environmental Science and ‡Atmospheric Sciences Program, Department of Physics University of Nevada-Reno , Reno, Nevada 89557, United States
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33
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Fu X, Marusczak N, Wang X, Gheusi F, Sonke JE. Isotopic Composition of Gaseous Elemental Mercury in the Free Troposphere of the Pic du Midi Observatory, France. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5641-5650. [PMID: 27214126 DOI: 10.1021/acs.est.6b00033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Understanding the sources and transformations of mercury (Hg) in the free troposphere is a critical aspect of global Hg research. Here we present one year of observations of atmospheric Hg speciation and gaseous elemental Hg (GEM) isotopic composition at the high-altitude Pic du Midi Observatory (2860 m above sea level) in France. Biweekly integrated GEM from February 2012 to January 2013 revealed significant variations in δ(202)HgGEM (-0.04‰ to 0.52‰) but not in Δ(199)HgGEM (-0.17‰ to -0.27‰) or Δ(200)HgGEM (-0.10‰ to 0.05‰). δ(202)HgGEM was negatively correlated with CO and reflected air mass origins from Europe (high CO, low δ(202)HgGEM) and from the Atlantic Ocean (low CO, high δ(202)HgGEM). We suggest that the δ(202)HgGEM variations represent mixing of recent low δ(202)HgGEM European anthropogenic emissions with high δ(202)HgGEM northern hemispheric background GEM. In addition, Atlantic Ocean free troposphere air masses showed a positive correlation between δ(202)HgGEM and gaseous oxidized Hg (GOM) concentrations, indicative of mass-dependent Hg isotope fractionation during GEM oxidation. On the basis of atmospheric δ(202)HgGEM and speciated Hg observations, we suggest that the oceanic free troposphere is a reservoir within which GEM is readily oxidized to GOM.
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Affiliation(s)
- Xuewu Fu
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , 46 Guanshui Road 550002, Guiyang, China
| | - Nicolas Marusczak
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
| | - Xun Wang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , 46 Guanshui Road 550002, Guiyang, China
| | - François Gheusi
- Observatoire Midi-Pyrénées, Laboratoire d'Aérologie, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
| | - Jeroen E Sonke
- Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université de Toulouse, 14, avenue Édouard Belin, 31400 Toulouse, France
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Peleg M, Tas E, Obrist D, Matveev V, Moore C, Gabay M, Luria M. Observational Evidence for Involvement of Nitrate Radicals in Nighttime Oxidation of Mercury. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:14008-14018. [PMID: 26551088 DOI: 10.1021/acs.est.5b03894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In the atmosphere, reactive forms of mercury species can be produced by oxidation of the dominant gaseous elemental mercury (GEM). The oxidation of GEM is an important driver for deposition, but oxidation pathways currently are poorly constrained and likely differ among regions. In this study, continuous measurements of atmospheric nitrate radical (NO3) concentrations and mercury speciation (i.e., elemental and reactive, oxidized forms) were performed during a six week period in the urban air shed of Jerusalem, Israel during summer 2012, to investigate the potential nighttime contribution of nitrate radicals to oxidized mercury formation. Average nighttime concentrations of reactive gaseous mercury (RGM) were almost equivalent to daytime levels (25 pg m(-3) and 27 pg m(-3) respectively), in contrast to early morning and evening RGM levels which dropped to low levels (9 and 13 pg m(-3)). During daytime, the presence of RGM was increased when solar radiation exceeded 200 W m(-2), suggesting a photochemical process for daytime RGM formation. Ozone concentrations were largely unrelated to daytime RGM. Nighttime RGM concentrations were relatively high (with a maximum of 97 pg m(-3)) compared to nighttime levels in other urban regions. A strong correlation was observed between nighttime RGM concentrations and nitrate radical concentration (R(2) averaging 0.47), while correlations to other variables were weak (e.g., RH; R(2) = 0.35) or absent (e.g., ozone, wind speed and direction, pollution tracers such as CO or SO2). Detailed analyses suggest that advection processes or tropospheric influences were unlikely to explain the strong nighttime correlations between NO3 and RGM, although these processes may contribute to these relationships. Our observations suggest that NO3 radicals may play a role in RGM formation, possibly due to a direct chemical involvement in GEM oxidation. Since physical data, however, suggest that NO3 unlikely initiates GEM oxidation, NO3 may play a secondary role in GEM oxidation through the addition to an unstable Hg(I) radical species.
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Affiliation(s)
- Mordechai Peleg
- Institute of Earth Sciences, Edmud Safra Campus, Givat Ram, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Eran Tas
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , P.O. Box 12, Rehovot 76100, Israel
| | - Daniel Obrist
- Desert Research Institute, Division of Atmospheric Sciences, 2215 Raggio Parkway, Reno, Nevada 89512, United States
| | - Valeri Matveev
- Institute of Earth Sciences, Edmud Safra Campus, Givat Ram, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - Christopher Moore
- Desert Research Institute, Division of Atmospheric Sciences, 2215 Raggio Parkway, Reno, Nevada 89512, United States
| | - Maor Gabay
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem , P.O. Box 12, Rehovot 76100, Israel
| | - Menachem Luria
- Institute of Earth Sciences, Edmud Safra Campus, Givat Ram, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
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