study of mercury and methylmercury transfers in the french alpine lakes

• Main Author: Marusczak, Nicolas
• Other Authors: Laboratoire de glaciologie et géophysique de l'environnement (LGGE), 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 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)-Centre National de la Recherche Scientifique (CNRS), Pacte, Laboratoire de sciences sociales (PACTE), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Sciences Po Grenoble - Institut d'études politiques de Grenoble (IEPG)-Centre National de la Recherche Scientifique (CNRS), Université de Grenoble, Ferrari Christophe([e-mail])
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2010
• Subjects: Mercury; Methylmercury; High Alpine Lakes; Snow; Atmospherics deposition; Mercure; Méthylmercure; Lacs Alpins; Neige; Dépôts atmosphériques; Arctic charr; Contamination; [CHIM.OTHE]Chemical Sciences/Other; [SDU.OTHER]Sciences of the Universe [physics]/Other; Arctic
• Online Access: https://theses.hal.science/tel-00553704; https://theses.hal.science/tel-00553704/document; https://theses.hal.science/tel-00553704/file/Manuscrit_Marusczak_Nicolas.pdf

Mercury (Hg), a toxic element for all life forms, is present in all environmental compartments. However, its biogeochemical cycle has been poorly studied in high-altitudes areas, particularly in the French Alps. This work presents the results of our study dedicated to the understanding of mercury dynamics in the French Alps lakes. The transfer of mercury species between different reservoirs such as snow (catchments), lake water and fishes was investigated during several field campaign conducted on four different lakes of the Massif de Belledone. Total mercury and methylmercury measurements in surface snow samples collected throughout the season suggest that anthropogenic Hg sources of the Grenoble area influence the chemical composition of the snowpacks. We also show that upon snowmelt, mercury and methylmercury are released to the lake water. However, a large proportion of Hg species seem to be rapidly drained out off the lake by an important renewal of water. Specific characteristics of the catchment areas also explain the low methylmercury content of lakes water. The low Hg content measured in fish could be attributed to a short residence time of mercury species in the lake. Finally, using a decision support tool (WARMF), we show that the physical and chemical properties of the lake and the catchments area could have a greater influence on Hg methylation and Hg levels in fish than the atmospheric Hg deposition. Le mercure, polluant toxique pour les êtres vivants est présent dans tous les compartiments de l'environnement. Son cycle biogéochimique est encore mal connu, et des lacunes existent, notamment dans les sites de hautes altitudes comme les Alpes françaises. Au cours de ces travaux, nous avons examiné la dynamique du mercure dans les écosystèmes lacustres alpins, par l'étude du transfert de ce polluant entre les différents réservoirs que sont la neige (bassin versant), l'eau des lacs, et les poissons. Par des échantillonnages réguliers (janvier à juin 2009) de la neige de surface du lac Bramant, nous ...