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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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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.
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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.
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Ali SW, Božič D, Vijayakumaran Nair S, Živković I, Gačnik J, Andron TD, Jagodic Hudobivnik M, Kocman D, Horvat M. Optimization of a pre-concentration method for the analysis of mercury isotopes in low-concentration foliar samples. Anal Bioanal Chem 2024; 416:1239-1248. [PMID: 38193932 PMCID: PMC10850019 DOI: 10.1007/s00216-023-05116-5] [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: 10/30/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 01/10/2024]
Abstract
Hg isotope analysis in samples from background regions is constrained by the presence of low Hg concentration and therefore requires a pre-concentration method. Existing Hg pre-concentration methods are constrained by long sample processing time and limited sample loading capacity. Using foliar samples as a test case, an optimized Hg pre-concentration method is presented that involves the microwave-assisted digestion of samples for Hg isotope analysis with the addition of a pre-digestion step. Microwave-digested foliar samples and CRMs were transferred to an impinger, reduced with SnCl2, and collected in a 2.25 mL concentrated inverse aqua regia (3:1 HNO3:HCl, v/v). This resulted in an optimal acid concentration in the solution ideal for analysis on MC-ICP-MS. The time for purging with Hg-free N2 was optimized to 30 min and the efficiency of the pre-concentration method was tested using a combination of approaches. Tests performed on pure reagents and matrix of foliar samples spiked with 197Hg radiotracer showed recoveries averaging 99 ± 1.7% and 100 ± 3.0%, respectively. Mercury at concentrations as low as 1.83 ng g-1 was pre-concentrated by digesting aliquots of foliage samples in individual digestion vessels. Recoveries following their pre-concentration averaged 99 ± 6.0%, whereas recoveries of 95 ± 4.7% and 95 ± 2.5% were achieved for NIST SRM 1575a (pine needle) and reagents spiked with NIST SRM 3133, respectively. Analysis using multicollector-ICP-MS showed low fractionation of δ202Hg during sample pre-concentration with no significant mass-independent fractionation. The proposed method is a relatively simple and robust way to prepare Hg samples for Hg isotopic analysis and is suitable even for complex biological matrices.
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Affiliation(s)
- Saeed Waqar Ali
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Dominik Božič
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Sreekanth Vijayakumaran Nair
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Igor Živković
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Jan Gačnik
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | - Teodor-Daniel Andron
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia
| | | | - David Kocman
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
| | - Milena Horvat
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia.
- Jožef Stefan International Postgraduate School, 1000, Ljubljana, Slovenia.
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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.
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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
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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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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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