Géraldine SARRET

Environmental Geochemist

Contact : geraldine.sarret at univ-grenoble-alpes.fr

Tel : 33 4 76 63 51 99

Research Interests

–  Fate of manufactured nanoparticles in the environment and impact on living organisms
–  Crops : fate of metals after root or foliar uptake ; implications for human exposure
–  The rhizosphere of higher plants :
1. Effects on the speciation of metals in the susbtrate, impacts on their bioavailability
2. Rôle of mycorrhizae on root uptake of metals and on metal tolerance of the plant
–  Metal hyperaccumulating plants : relationships between tolerance and hyperaccumulation traits and the mechanisms of metal uptake and sequestration
–  Soil microorganisms :
1. Mechanisms of metal sorption on the bacterial cell wall, role of the extracellular polymeric substances
2. Structure and function of proteins involved in metal tolerance processes
–  Speciation of metals in soils and sediments

Possible applications of these researches :

– Phytotechnologies for the remediation or management of metal contaminated soils
– Risk assessment : transfer of contaminants in trophic chains, human exposure
– Bioremediation

Approaches
I am using a combination of physical techniques, analytical chemistry and physico- chemistry to probe the status of metallic elements and characterize the systems at different scales, from the macro scale to the micro-nano and molecular scale. Physical techniques involve synchrotron X-ray beam, electron or particles, for bulk analyses, and provide 2D and 3D imaging and speciation of elements. I am also using thermodynamic models to predict sorption, complexation, precipitation, redox reactions. I am combining these techniques with stable isotope measurements, in collaboration with experts in isotope geochemistry. These approaches are used on natural samples from the field and on model systems in controlled conditions. The main experimental challenges are the low concentration of the studied metals, and the sample preparation of biological samples with high water content (plant leaves for example) with preservation of the localization and speciation of elements.

Fundings
French research programs (CNRS, Ministry of Environment, ANR, LabEx : OSUG@2020 and Serenade, EquipEx : NanoID)
European programs (Marie Curie fellowships, 7th PCRD : NanoHouse collaborative project)

Responsabilities
Member (2010-2014) and then Head (2015-2017) of the SOLEIL and CRG review committee for beamtime applications in Environmental Sciences & Cultural Heritage (CP6)
Member of the IMBG executive board (Institut des Métaux en Biologie de Grenoble) (2012-present)
Head of the Geochemistry Group at ISTerre (11 researchers, 5 technicians and engineers, 10 PhD students and post docs) (2013-2017)
Associate Editor for the Journal of Environmental Quality (2009-2016)
Member of the Scientific Committee of BIOEFFECT Action, CNRS (2011-2015)
Member of ISTEB executive board (2011-2015)
Member of the ESRF review committee for beamtime applications (2006-2009)
Member of the User’s committee of SOLEIL synchrotron (2006-2008)

Teaching
– EXAFS spectroscopy and related techniques - Applications in earth and environmental sciences
– Biogeochemistry of the rhizosphere
– Phytoremediation
– Spectroscopic and imaging techniques : acquisition and data treatment

Publication list