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1. Interaction of reactive mercury with surfaces and implications for atmospheric mercury speciation measurements

   https://doi.org/10.1016/j.atmosenv.2023.120240  

   Allen, Natalie; Gačnik, Jan; Dunham-Cheatham, Sarrah M.; Gustin, Mae Sexauer (February 2024, Atmospheric Environment)

   Accurate measurement of atmospheric reactive mercury (RM) presents analytical challenges due to its reactivity and ultra-trace concentrations. In the last decade, use of the University of Nevada, Reno – Reactive Mercury Active System (RMAS) for RM measurements has increased since it has been shown to be more accurate than the industry standard, the Tekran 2537/1130/1135 system. However, RMAS measurements also have limitations, including long time resolution and sampling biases associated with membranes used for RM sampling. We therefore investigated the use of higher sampling flow rates to reduce sampling time and tested alternative membrane materials using both ambient air sampling and controlled laboratory experiments with a gaseous oxidized mercury (GOM) calibrator. Results indicated that increasing the RMAS sampling flow had a negative impact on determined RM concentrations. RM concentrations at 2 L min−1 were 10% and 30–50% lower than at 1 L min−1 in spring/summer and winter, respectively. However, the chemical composition of RM captured on membranes was not impacted by the increased flow rate. Membranes currently used in the RMAS performed better than numerous alternatives with similar composition, retaining Hg more efficiently. Both ambient air sampling and laboratory experiments revealed that membranes designed to retain only particulate-bound mercury (PBM) also retained significant amounts of GOM. PBM membranes based on borosilicate glass designs retained more than 70% of GOM. 

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2. New Approaches to Understand Mercury in Trees: Radial and Longitudinal Patterns of Mercury in Tree Rings and Genetic Control of Mercury in Maple Sap

   https://doi.org/10.1007/s11270-020-04601-2  

   Yanai, Ruth D.; Yang, Yang; Wild, Adam D.; Smith, Kevin T.; Driscoll, Charles T. (May 2020, Water, Air, & Soil Pollution)

   null (Ed.)
3. Updated Global and Oceanic Mercury Budgets for the United Nations Global Mercury Assessment 2018

   https://doi.org/10.1021/acs.est.8b01246  

   Outridge, P. M.; Mason, R. P.; Wang, F.; Guerrero, S.; Heimbürger-Boavida, L. E. (October 2018, Environmental Science & Technology)
4. Arctic mercury cycling

   https://doi.org/10.1038/s43017-022-00269-w  

   Dastoor, Ashu; Angot, Hélène; Bieser, Johannes; Christensen, Jesper H.; Douglas, Thomas A.; Heimbürger-Boavida, Lars-Eric; Jiskra, Martin; Mason, Robert P.; McLagan, David S.; Obrist, Daniel; et al (April 2022, Nature Reviews Earth & Environment)
5. Aqueous Elemental Mercury Production versus Mercury Inventories in the Lake Michigan Airshed: Deciphering the Spatial and Diel Controls of Mercury Gradients in Air and Water

   https://doi.org/10.1021/acsestwater.0c00187  

   Lepak, Ryan F.; Tate, Michael T.; Ogorek, Jacob M.; DeWild, John F.; Peterson, Benjamin D.; Hurley, James P.; Krabbenhoft, David P. (January 2020, ACS ES&T Water)

   null (Ed.)

   Atmospheric delivery of mercury (Hg) is important to the Upper Great Lakes, and understanding gaseous Hg exchange between surface water and air is critical to predicting the effects of declining mercury emissions. Speciated atmospheric Hg, dissolved gaseous Hg (DGM), and particulate and filter passing total Hg were measured on a cruise in Lake Michigan. Low mercury levels reflected pristine background conditions, especially in offshore regions. In the atmosphere, reactive and particle-associated fractions were low (1.0 ± 0.5%) compared to gaseous elemental Hg (1.34 ± 0.14 ng m–3) and were elevated in the urbanized southern basin. DGM was supersaturated, ranging from 17.5 ± 4.8 pg L–1 (330 ± 80%) in the main lake to 33.2 ± 2.4 pg L–1 (730 ± 70%) in Green Bay. Diel cycling of surface DGM showed strong Hg efflux during the day due to increased winds, and build-up at night from continued DGM production. Epilimnetic DGM is formed from photochemical reduction, while hypolimnetic DGM originates from biological Hg reduction. We found that DGM concentrations were greatest below the thermocline (30.8 ± 13.6 pg L–1), accounting for 68–92% of the total DGM in Lake Michigan, highlighting the importance of nonphotochemical reduction in deep stratified lakes. 

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