Observations of the chemistry and concentrations of reactive Hg at locations with different ambient air chemistry

Mae Sexauer Gustin; Sarrah M Dunham-Cheatham; Natalie Allen; Nicole Choma; William Johnson; Sam Lopez; Armistead Russell; Eric Mei; Olivier Magand; Aurélien Dommergue; Tyler Elgiar

doi:10.1016/j.scitotenv.2023.166184

Observations of the chemistry and concentrations of reactive Hg at locations with different ambient air chemistry

Sci Total Environ. 2023 Dec 15:904:166184. doi: 10.1016/j.scitotenv.2023.166184. Epub 2023 Aug 14.

Authors

Affiliations

¹ Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV, USA. Electronic address: mgustin@unr.edu.
² College of Agriculture, Biotechnology & Natural Resources, University Nevada, Reno, NV, USA.
³ Department of Natural Resources & Environmental Science, University of Nevada, Reno, NV, USA.
⁴ Department of Geology & Geophysics, University of Utah, Salt Lake City, UT, USA.
⁵ School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
⁶ 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.
⁷ Univ. Grenoble Alpes, CNRS, INRAE, IRD, Grenoble INP(1), IGE, 38000 Grenoble, France.
⁸ Bingham Research Center, Utah State University, Vernal, UT, USA.

PMID: 37586514
DOI: 10.1016/j.scitotenv.2023.166184

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 Hg^II compounds. At Great Salt Lake, Utah (GSL), RM was predominately PBM, with NS > organics > halogen > O Hg^II 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 Hg^II 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.

Keywords: GEOS-Chem; Gaseous oxidized mercury; HYSPLIT; Mercury; Particulate-bound mercury.