1
|
Feinberg A, Selin NE, Braban CF, Chang KL, Custódio D, Jaffe DA, Kyllönen K, Landis MS, Leeson SR, Luke W, Molepo KM, Murovec M, Nerentorp Mastromonaco MG, Aspmo Pfaffhuber K, Rüdiger J, Sheu GR, St Louis VL. Unexpected anthropogenic emission decreases explain recent atmospheric mercury concentration declines. Proc Natl Acad Sci U S A 2024; 121:e2401950121. [PMID: 39378086 DOI: 10.1073/pnas.2401950121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 09/05/2024] [Indexed: 10/10/2024] Open
Abstract
Anthropogenic activities emit ~2,000 Mg y-1 of the toxic pollutant mercury (Hg) into the atmosphere, leading to long-range transport and deposition to remote ecosystems. Global anthropogenic emission inventories report increases in Northern Hemispheric (NH) Hg emissions during the last three decades, in contradiction with the observed decline in atmospheric Hg concentrations at NH measurement stations. Many factors can obscure the link between anthropogenic emissions and atmospheric Hg concentrations, including trends in the reemissions of previously released anthropogenic ("legacy") Hg, atmospheric sink variability, and spatial heterogeneity of monitoring data. Here, we assess the observed trends in gaseous elemental mercury (Hg0) in the NH and apply biogeochemical box modeling and chemical transport modeling to understand the trend drivers. Using linear mixed effects modeling of observational data from 51 stations, we find negative Hg0 trends in most NH regions, with an overall trend for 2005 to 2020 of -0.011 ± 0.006 ng m-3 y-1 (±2 SD). In contrast to existing emission inventories, our modeling analysis suggests that annual NH anthropogenic emissions must have declined by at least 140 Mg between the years 2005 and 2020 to be consistent with observed trends. Faster declines in 95th percentile Hg0 values than median values in Europe, North America, and East Asian measurement stations corroborate that the likely cause is a decline in nearby anthropogenic emissions rather than background legacy reemissions. Our results are relevant for evaluating the effectiveness of the Minamata Convention on Mercury, demonstrating that existing emission inventories are incompatible with the observed Hg0 declines.
Collapse
Affiliation(s)
- Aryeh Feinberg
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Noelle E Selin
- Institute for Data, Systems, and Society, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Christine F Braban
- United Kingdom Centre for Ecology and Hydrology, Penicuik, Midlothian EH26 0QB, United Kingdom
| | - Kai-Lan Chang
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309
- National Oceanic and Atmospheric Administration Chemical Sciences Laboratory, Boulder, CO 80305
| | | | - Daniel A Jaffe
- School of Science, Technology, Engineering & Mathematics, Physical Sciences Division, University of Washington Bothell, Bothell, WA 98011
- Department of Atmospheric Sciences, University of Washington Seattle, Seattle, WA 98195
| | - Katriina Kyllönen
- Atmospheric Composition Research, Finnish Meteorological Institute, Helsinki 00560, Finland
| | - Matthew S Landis
- United States Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC 27711
| | - Sarah R Leeson
- United Kingdom Centre for Ecology and Hydrology, Penicuik, Midlothian EH26 0QB, United Kingdom
| | - Winston Luke
- National Oceanic and Atmospheric Administration/Air Resources Laboratory, College Park, MD 20740
| | - Koketso M Molepo
- Institute of Coastal Environmental Chemistry, Helmholtz Zentrum Hereon, Geesthacht 21502, Germany
| | - Marijana Murovec
- Slovenian Environment Agency, Environment and Nature protection Office, Air Quality Division, Ljubljana 1000, Slovenia
| | | | | | - Julian Rüdiger
- Air Monitoring Network, German Environment Agency, Langen 63225, Germany
| | - Guey-Rong Sheu
- Department of Atmospheric Sciences, National Central University, Taoyuan 320, Taiwan
| | - Vincent L St Louis
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| |
Collapse
|
2
|
Gačnik J, Lyman S, Dunham-Cheatham SM, Gustin MS. Limitations and insights regarding atmospheric mercury sampling using gold. Anal Chim Acta 2024; 1319:342956. [PMID: 39122272 DOI: 10.1016/j.aca.2024.342956] [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: 02/29/2024] [Revised: 07/03/2024] [Accepted: 07/07/2024] [Indexed: 08/12/2024]
Abstract
BACKGROUND Atmospheric mercury (Hg) concentrations are quantified primarily through preconcentration on gold (Au) cartridges through amalgamation and subsequent thermal desorption into an atomic fluorescence spectrometry detector. This procedure has been used for decades, and is implemented in the industry-standard atmospheric Hg analyzer, the Tekran 2537. There is ongoing debate as to whether gaseous elemental mercury (Hg0) or total gaseous mercury (TGM, Hg0 + HgII) is measured using Au cartridges. The raw Hg signal processing algorithms for the Tekran 2537 analyzer have also been questioned. The objective of this work was to develop a better understanding of what forms of Hg are collected on gold cartridges through the use of permeation tube-based calibrators, that release known amounts of Hg0 and HgII. The potential differences between different Tekran analyzer models (i.e., 2537B versus 2537X) Hg signal processing algorithms, and Hg0 calibration methods were also investigated. RESULTS Experiments were performed using Hg0 and HgII permeation calibrators. Validation tests showed that the HgII calibrator produced a reproducible and stable HgII permeation rate (2.2 ± 0.2 pg min-1). Results of HgII sampling and analysis using Au amalgamation showed the gold cartridges measured up to 75 % HgII, with the value at the beginning of the HgII measurement being much lower (as low as 10 %) due to HgII adsorption on analyzer surfaces and the Tekran particulate filter. Furthermore, thermal desorption of Hg from Au reduced only 80 % of HgII to Hg0, resulting in additional HgII that was not measured by the analyzer. By adding a thermolyzer upstream of the analyzer, 97 % of HgII was measured as Hg0. Additionally, Hg0 measurements using Tekran 2537 B and X models using a newly developed signal processing algorithm, different peak integration methods, and two Hg0 sources were compared. Results showed the 2537X model was not affected by the integration type, while the 2537B model was. Bell jar calibration based on the Dumarey equation resulted in 6 % ± 7 % (mean ± SD) underestimation of measured Hg0 concentrations compared to the calibration with a permeation calibrator. SIGNIFICANCE Gold cartridges measured an atmospheric Hg fraction somewhere between Hg0 and TGM due to HgII adsorption and inefficient reduction of HgII to Hg0 during thermal desorption from Au. Since HgII in ambient air can be 25 % of total Hg, distinguishing between Hg0 and TGM is important. The use of a thermolyzer or a cation exchange membrane upstream of gold cartridges is recommended to enable TGM or Hg0 measurements, respectively. Observations showed that traceable multipoint calibrations of atmospheric Hg measurements are needed for Hg quantification, and that different Hg0 calibration methods can produce significantly different results for measured atmospheric Hg concentrations.
Collapse
Affiliation(s)
- Jan Gačnik
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, USA.
| | - Seth Lyman
- Bingham Research Center, Utah State University, Vernal, USA
| | | | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, USA
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Vijayakumaran Nair S, Gačnik J, Živković I, Andron TD, Ali SW, Kotnik J, Horvat M. Application of traceable calibration for gaseous oxidized mercury in air. Anal Chim Acta 2024; 1288:342168. [PMID: 38220300 DOI: 10.1016/j.aca.2023.342168] [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: 10/06/2023] [Revised: 11/28/2023] [Accepted: 12/17/2023] [Indexed: 01/16/2024]
Abstract
BACKGROUND The current speciation methods for mercury (Hg) measurements are fraught with considerable uncertainty, from sample collection to calibration. High reactivity of gaseous oxidized Hg (GOM) species and their ultra-trace level presence makes them difficult to sample and calibrate. Given that improper calibration may lead to measurement biases, reliable and metrologically traceable calibration methods are required for accurately quantifying GOM in air. In the present study, we applied the recently developed calibration method based on non-thermal plasma oxidation of elemental Hg, to a commercially available Hg air speciation system for actual environmental measurements of GOM for the first time. RESULTS Hg species such as HgO, HgCl2, and HgBr2 were produced with trace amounts of reactant gases (oxygen and electrolytically produced chlorine and bromine) and the production was driven by plasma-assisted oxidation. The plasma oxidation efficiency of elemental Hg with oxygen was 98.5 ± 7.5 % (k = 2), while that for chlorine and bromine was 96.8 ± 6.9 % (k = 2) and 97.4 ± 9.6 % (k = 2), respectively. The calibration method was tested against the internal permeation (Hg0) source of the Tekran 2537B Hg analyzer on-field by loading HgO to different KCl-coated denuders using the plasma. GOM concentrations were measured using the Tekran speciation system. With internal calibration, concentrations were up to 9.1 % lower than those in plasma calibration, thereby emphasizing the importance of the calibration strategy. Measurement uncertainty (k = 2) further emphasizes this distinction. Internal calibration measurement uncertainty was 36.8 %, while plasma calibration boasted lower uncertainty at 13.8 %. SIGNIFICANCE The non-thermal plasma calibration strategy, as a unique and discrete calibration method traceable to the NIST SRM 3133 for ambient air GOM measurements, provide a higher level of confidence in the accuracy of GOM measurements with several advantages over other methods. Calibrations at extreme low concentrations (<100 pg) are possible with this method relevant to ambient air GOM concentrations.
Collapse
Affiliation(s)
- 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
| | - 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; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000, Ljubljana, Slovenia
| | - Teodor Daniel Andron
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000, Ljubljana, Slovenia
| | - Saeed Waqar Ali
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000, Ljubljana, Slovenia
| | - 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
| | - 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.
| |
Collapse
|
6
|
Gustin MS, Dunham-Cheatham SM, Allen N, Choma N, Johnson W, Lopez S, Russell A, Mei E, Magand O, Dommergue A, Elgiar T. Observations of the chemistry and concentrations of reactive Hg at locations with different ambient air chemistry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166184. [PMID: 37586514 DOI: 10.1016/j.scitotenv.2023.166184] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/07/2023] [Accepted: 08/07/2023] [Indexed: 08/18/2023]
Abstract
The Hg research community needs methods to more accurately measure atmospheric Hg concentrations and chemistry. The Reactive Mercury Active System (RMAS) uses cation exchange, nylon, and PTFE membranes to determine reactive mercury (RM), gaseous oxidized mercury, and particulate-bound mercury (PBM) concentrations and chemistry. New data for Atlanta, Georgia (NRGT) demonstrated that particulate-bound Hg was dominant and the chemistry was primarily N and S HgII compounds. At Great Salt Lake, Utah (GSL), RM was predominately PBM, with NS > organics > halogen > O HgII compounds. At Guadalupe Mountains National Park, Texas (GUMO), halogenated compound concentrations were lowest when air interacting with the site was primarily derived from the Midwest, and highest when the air was sourced from Mexico. At Amsterdam Island, Southern Indian Ocean, compounds were primarily halogenated with some N, S, and organic HgII compounds potentially associated with biological activity. The GEOS-Chem model was applied to see if it predicted measurements at five field sites. Model values were higher than observations at GSL, slightly lower at NRGT, and observations were an order of magnitude higher than modeled values for GUMO and Reno, Nevada. In general, data collected from 13 locations indicated that N, S, and organic RM compounds were associated with city and forest locations, halogenated compounds were sourced from the marine boundary layer, and O compounds were associated with long-range transport. Data being developed currently, and in the past, suggest there are multiple forms of RM that modelers must consider, and PBM is an important component of RM.
Collapse
Affiliation(s)
- Mae Sexauer Gustin
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV, USA.
| | | | - Natalie Allen
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV, USA
| | - Nicole Choma
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV, USA
| | - William Johnson
- Department of Geology & Geophysics, University of Utah, Salt Lake City, UT, USA
| | - Sam Lopez
- Department of Geology & Geophysics, University of Utah, Salt Lake City, UT, USA
| | - Armistead Russell
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Eric Mei
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Olivier Magand
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP(1), IGE, 38000 Grenoble, France; 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
| | - Aurélien Dommergue
- Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP(1), IGE, 38000 Grenoble, France
| | - Tyler Elgiar
- Bingham Research Center, Utah State University, Vernal, UT, USA
| |
Collapse
|
7
|
Dunham-Cheatham SM, Lyman S, Gustin MS. Comparison and calibration of methods for ambient reactive mercury quantification. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159219. [PMID: 36202360 DOI: 10.1016/j.scitotenv.2022.159219] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/28/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Gaseous oxidized mercury (GOM) is the dominant form of atmospheric mercury (Hg) deposited and sequestered within ecosystems. Thus, accurate, calibrated measurements of GOM are needed. Here, two active membrane-based collection systems (RMAS) were used to determine GOM and particulate-bound Hg (PBM), as well as reactive Hg (RM = GOM + PBM), and compared with two dual-channel systems (DCS) and a Tekran 2537/1130 speciation system. The DCS measured operationally defined GOM by difference, using concentrations of gaseous elemental Hg (GEM) and total gaseous Hg. One DCS was linked to a custom-built, automated calibration system that permeated GEM, HgBr2, or HgCl2. The five systems were co-located for one-year to develop a dataset that would allow for understanding limitations of each system, and assessing measurement accuracy and long-term precision of the calibrator. The Tekran system measured ~14.5 % of the GOM measured by the other systems. The USU and UNR DCS and RMAS were significantly correlated, but the DCS was 50 and 30 % higher, respectively, than the RMAS. The calibrator performed consistently in the field and lab, and the DCS fully recovered GOM injected by the calibrator. Since the uncalibrated DCS measured the same concentrations as the calibrated DCS, they are both accurate methods for measuring RM and/or GOM. Some loss occurred from the RMAS membranes. SYNOPSIS: Accurate and calibrated measurements of atmospheric reactive mercury using membranes and two dual-channel systems.
Collapse
Affiliation(s)
- Sarrah M Dunham-Cheatham
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, 1664 N. Virginia Street, Mail Stop 186, Reno, NV 89557, USA.
| | - Seth Lyman
- Bingham Research Center, Utah State University, 320 N Aggie Blvd, Vernal, UT 84078, USA; Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, UT 84322, USA
| | - Mae Sexauer Gustin
- Department of Natural Resources & Environmental Science, University of Nevada, Reno, 1664 N. Virginia Street, Mail Stop 186, Reno, NV 89557, USA
| |
Collapse
|
8
|
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.
Collapse
|
9
|
Vijayakumaran Nair S, Kotnik J, Gačnik J, Živković I, Koenig AM, Mlakar TL, Horvat M. Dispersion of airborne mercury species emitted from the cement plant. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 312:120057. [PMID: 36041570 DOI: 10.1016/j.envpol.2022.120057] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/06/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
The cement industry is the second largest source of anthropogenic mercury (Hg) emissions in Europe, accounting for 11% of global anthropogenic Hg emissions. The main objective of this study was to examine the influence of Hg emissions from the Salonit Anhovo cement plant on Hg levels measured in the ambient air at Vodarna, 1 km downwind from the flue gas chimney. The findings reveal that the plant raw mill operational status plays an important role in Hg concentrations in the flue gas emitted from the plant. Emitted total gaseous mercury was, on average, higher (49.4 μg/m3) when raw mills were in the direct mode (both raw mills-off) and lower (23.4 μg/m3) in the combined mode (both raw mills-on). The average Hg concentrations in Vodarna were 3.14 ng/m3 for gaseous elemental mercury, 53.7 pg/m3 for gaseous oxidised mercury, and 41.9 pg/m3 for particulate bound mercury for the whole measurement period. Atmospheric Hg speciation in Vodarna, coupled with plant emissions and wind data, has revealed that the total gaseous mercury emitted from the cement plant is clearly related to all Hg species measured in Vodarna. Wind blowing from the northeastern quadrant (mostly NE, ENE) is responsible for the elevated Hg levels in Vodarna, where gaseous oxidised mercury levels are highly linked to the cement plant emissions. However, elevated levels of Hg species in the absence of northeastern winds indicate potential inputs from other unknown local sources as well as inputs from regional and global transport mechanisms.
Collapse
Affiliation(s)
- Sreekanth Vijayakumaran Nair
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia; Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Jože Kotnik
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia; Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - 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
| | - Igor Živković
- Department of Environmental Sciences, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Alkuin Maximilian Koenig
- Institut des Géosciences de l'Environnement, Université Grenoble Alpes, CNRS, IRD, Grenoble INP, Grenoble, France
| | | | - 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.
| |
Collapse
|
10
|
Davis M, Lu J. Calibration Sources for Gaseous Oxidized Mercury: A Review of Source Design, Performance, and Operational Parameters. Crit Rev Anal Chem 2022; 54:1748-1757. [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] [MESH Headings] [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.
Collapse
Affiliation(s)
- Matthew Davis
- Department of Chemistry and Biology, Ryerson University, Toronto, Canada
| | - Julia Lu
- Department of Chemistry and Biology, Ryerson University, Toronto, Canada
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Gustin MS, Dunham-Cheatham SM, Zhang L, Lyman S, Choma N, Castro M. Use of Membranes and Detailed HYSPLIT Analyses to Understand Atmospheric Particulate, Gaseous Oxidized, and Reactive Mercury Chemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:893-901. [PMID: 33404225 DOI: 10.1021/acs.est.0c07876] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The atmosphere is the primary pathway by which mercury enters ecosystems. Despite the importance of atmospheric deposition, concentrations and chemistry of gaseous oxidized (GOM) and particulate-bound (PBM) mercury are poorly characterized. Here, three membranes (cation exchange (CEM), nylon, and poly(tetrafluoroethylene) (PTFE) membranes) were used as a means for quantification of concentrations and identification of the chemistry of GOM and PBM. Detailed HYSPLIT analyses were used to determine sources of oxidants forming reactive mercury (RM = PBM + GOM). Despite the coarse sampling resolution (1-2 weeks), a gradient in chemistry was observed, with halogenated compounds dominating over the Pacific Ocean, and continued influence from the marine boundary layer in Nevada and Utah with a periodic occurrence in Maryland. Oxide-based RM compounds arrived at continental locations via long-range transport. Nitrogen, sulfur, and organic RM compounds correlated with regional and local air masses. RM concentrations were highest over the ocean and decreased moving from west to east across the United States. Comparison of membrane concentrations demonstrated that the CEM provided a quantitative measure of RM concentrations and PTFE membranes were useful for collecting PBM. Nylon membranes do not retain all compounds with equal efficiency in ambient air, and an alternate desorption surface is needed.
Collapse
Affiliation(s)
- 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
| | - Lei Zhang
- School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, China
| | - Seth Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84322, United States
| | - Nicole Choma
- 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
| |
Collapse
|
16
|
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.
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|