Atmospheric mercury depletion event study in Ny-Alesund (Svalbard) in spring 2005. Deposition and transformation of Hg in surface snow during springtime

Christophe P. Ferrari (1, 2) , Cyril Padova (1) , Xavier Faïn (1) , Pierre-Alexis Gauchard (1) , Aurélien Dommergue (1, 2) , Katrine Aspmo (3, 4) , Torunn Berg (3) , Warren R. L. Cairns (5) , Carlo Barbante (5, 6) , Paolo Cescon (5, 6) , Lars Kaleschke (7) , Andreas Richter (8) , Folkard Wittrock (8) , Claude F. Boutron (1, 9)

1 LGGE - Laboratoire de glaciologie et géophysique de l'environnement
2 Polytech' Grenoble
3 NILU - Norwegian Institute for Air Research
4 Department of Chemistry [Oslo]
5 Institute for the Dynamics of Environmental Processes-CNR
6 Environmental Sciences Department
7 Institute of Oceanography [Hamburg]
8 IUP - Institute of Environmental Physics [Bremen]
9 Unité de Formation et de Recherche de Physique

A field campaign was conducted in Ny-Ǻlesund (78°54'N, 11°53'E), Svalbard (Norway) during April and May 2005. An Atmospheric Mercury (Hg) Depletion Event (AMDE) was observed from the morning of April 24 until the evening of April 27. Transport of already Hg and ozone (O3) depleted air masses could explain this observed depletion. Due to a snowfall event during the AMDE, surface snow Hg concentrations increased two fold. Hg deposition took place over a short period of time corresponding to 3–4 days. More than 80% of the deposited Hg was estimated to be reemitted back to the atmosphere in the days following the event. During the campaign, we observed night and day variations in surface snow Hg concentrations, which may be the result of gaseous elemental mercury (GEM) oxidation to divalent Hg at the snow/air interface by daylight surface snow chemistry. Finally, a decrease in the reactive Hg (HgR) fraction of total Hg (HgT) in the surface snow was observed during spring. We postulate that the transformation of HgR to a more stable form may occur in Arctic snow during spring.

Keywords: Mercury; Snow; Deposition; Chemical transformation; AMDEs

Domains: Sciences of the Universe [physics]; Earth Sciences; Glaciology

Christophe P. Ferrari, Cyril Padova, Xavier Faïn, Pierre-Alexis Gauchard, Aurélien Dommergue, et al.. Atmospheric mercury depletion event study in Ny-Alesund (Svalbard) in spring 2005. Deposition and transformation of Hg in surface snow during springtime. Science of the Total Environment, 2008, 397 (1-3), pp.167 à 177. ⟨10.1016/j.scitotenv.2008.01.064⟩. ⟨insu-00378389⟩