Feedback mechanisms between snow and atmospheric mercury: Results and observations from field campaigns on the Antarctic
plateau

Year: 2018

Authors: Spolaor A., Angot H., Roman M., Dommergue A., Scarchilli C., Vard M., Del Guasta M., Pedeli X., Varin C., Sprovieri F., Magand O., Legrand M., Barbante C., Cairns W.

Autors Affiliation: CNR, Inst Dynam Environm Proc IDPA, I-30172 Venice, Italy; Univ Grenoble Alpes, CNRS, IRD, IGE, F-38000 Grenoble, France; ENEA, CR Casaccia, I-00123 Rome, Italy; CNR, INO, I-50019 Sesto Fiorentino, Italy; Univ Ca Foscari Venice, Dept Environm Sci Informat & Stat, I-30172 Venice, Italy; CNR, Inst Atmospher Pollut Res IIA, Div Rende, I-87036 Arcavacata Di Rende, Italy; MIT, Inst Data Syst & Soc, Cambridge, MA 02139 USA.

Abstract: The Antarctic Plateau snowpack is an important environment for the mercury geochemical cycle. We have extensively characterized and compared the changes in surface snow and atmospheric mercury concentrations that occur at Dome C. Three summer sampling campaigns were conducted between 2013 and 2016. The three campaigns had different meteorological conditions that significantly affected mercury deposition processes and its abundance in surface snow. In the absence of snow deposition events, the surface mercury concentration remained stable with narrow oscillations, while an increase in precipitation results in a higher mercury variability. The Hg concentrations detected confirm that snowfall can act as a mercury atmospheric scavenger. A high temporal resolution sampling experiment showed that surface concentration changes are connected with the diurnal solar radiation cycle. Mercury in surface snow is highly dynamic and it could decrease by up to 90% within 4/6 h. A negative relationship between surface snow mercury and atmospheric concentrations has been detected suggesting a mutual dynamic exchange between these two environments. Mercury concentrations were also compared with the Br concentrations in surface and deeper snow, results suggest that Br could have an active role in Hg deposition, particularly when air masses are from coastal areas. This research presents new information on the presence of Hg in surface and deeper snow layers, improving our understanding of atmospheric Hg deposition to the snow surface and the possible role of re-emission on the atmospheric Hg concentration.

Journal/Review: CHEMOSPHERE

Volume: 197      Pages from: 306  to: 317

More Information: This work was supported by the Programma Nazionale per la Ricerca in Antartide (PNRA, project number 2013/AC3.03 PEA 2013-2015). Analytical instrument resources for the elements determination in the snow were provided by the Institute for the Dynamic of Environmental Process (IDPA-CNR) of the National Research Council. Atmospheric Hg measurements were also supported by the FP7 (2010-2015) Global Mercury Observation System (GMOS) project. This work contributed to the EU-FP7 project Global Mercury Observation System (GMOS, www.gmos.eu) and has been supported by a grant from Labex OSUG@2020 (Investissements d’avenir – ANR10 LABX56). Logistical and financial support was provided by the French Polar Institute IPEV (Program 1028, GMOstral). Helene Angot, Olivier Magand, and Aurelien Dommergue thank the overwintering crew: S. Aubin, A. Barbero, N. Hueber, C. Lenormant, R. Jacob, and P. Serre at DC. Calculations, model comparison and analysis have been conducted in the framework of the PRE-REC projects, funded by PNRA-MIUR. Data and meteorological information were obtained from IPEV/PNRA Project Routine Meteorological Observation at Station Concordia’ http://www.climantartide.it/. The authors gratefully acknowledge Elga Lab water for the supply of the ultrapure water systems used during this study.
KeyWords: Deposition; Domes; Mercury (metal); Precipitation (chemical), Antarctica; Atmospheric concentration; Feedback mechanisms; Halogens; High temporal resolution; Mercury concentrations; Meteorological condition; Surface concentration, Snow, mercury; snow; mercury; salt water; snow, air mass; atmospheric chemistry; atmospheric deposition; bromine; climate conditions; coastal zone; concentration (composition); diurnal variation; feedback mechanism; field survey; geochemistry; halogen; mercury (element); precipitation (chemistry); sampling; scavenging (chemistry); snowpack; solar radiation; surface, Article; concentration (parameters); feedback system; meteorology; oscillation; precipitation; seashore; solar radiation; summer; surface property; air pollutant; analysis; Antarctica; atmosphere; chemistry; environmental monitoring; season, Antarctic Plateau; Antarctica; Dome Concordia; East Antarctica, Air Pollutants; Antarctic Regions; Atmosphere; Environmental Monitoring; Mercury; Saline Waters; Seasons; Snow
DOI: 10.1016/j.chemosphere.2017.12.180

Citations: 12
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