Mercury in the snow and firn at Summit Station, Central Greenland, and implications for the study of past atmospheric mercury levels

• Main Authors: Faïn, X., Ferrari, C. P., Dommergue, A., Albert, M., Battle, M., Arnaud, L., Barnola, J.-M., Cairns, W., Barbante, C., Boutron, C.
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Polytech' Grenoble, Université Joseph Fourier - Grenoble 1 (UJF), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Geophysical Sciences Division Hanover, ERDC Cold Regions Research and Engineering Laboratory (CRREL), USACE Engineer Research and Development Center (ERDC)-USACE Engineer Research and Development Center (ERDC), Department of Physics and Astronomy Brunswick, Bowdoin College Brunswick, Environmental Sciences Department, University of Ca’ Foscari Venice, Italy, Unité de Formation et de Recherche de Physique
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Greenland
• Online Access: https://hal.archives-ouvertes.fr/hal-00328252; https://hal.archives-ouvertes.fr/hal-00328252/document; https://hal.archives-ouvertes.fr/hal-00328252/file/acpd-7-18221-2007.pdf

International audience Gaseous Elemental Mercury (Hg° or GEM) was investigated at Summit Station, Greenland, in the interstitial air extracted from the perennial snowpack (firn) at depths ranging from the surface to 30 m, during summer 2005 and spring 2006. Photolytic production and destruction of Hg° were observed close to the snow surface during summer 2005 and spring 2006, and we observed dark oxidation of GEM up to 270 cm depth in June 2006. Photochemical transformation of gaseous mercury resulted in diel variations in the concentrations of this gas in the near-surface interstitial air, but destruction of Hg° was predominant in June, and production was the main process in July. This seasonal evolution of the chemical mechanisms involving gaseous elemental mercury produces a signal that propagates downward through the firn air, but is unobservably small below 15 m in depth. As a consequence, multi-annual averaged records of GEM concentration should be well preserved in deep firn air at depths below 15 m, and available for the reconstruction of the past atmospheric history of GEM over the last decades.