Missions

Predicting the biogeochemical behavior of trace metals and metalloids (TMEs; e.g. As, Cr, U, Cu) in natural systems is a major concern due to the serious threats they pose to human health, aquatic life and the environment. We know that the transport, bioavailability and/or toxicity of TMEs in the environment depend on their speciation, particularly their interaction with colloids. However, the determination of ETM speciation is hampered by the lack of knowledge of colloidal phases, their physico-chemical properties and the dynamics of this colloidal pool as a function of environmental conditions. Consequently, further work is needed to determine their future trajectory under the influence of changing environmental conditions associated with climate forcing and the resulting climatic transition. The project will focus on colloid dynamics under the influence of various bio/hydro/pedological and climatic constraints inducing variations in the physico-chemical conditions of the environment (e.g. Eh, pH, T, salinity fluctuations or gradients) and exchanges between the colloidal compartment and the dissolved or particulate phases. Colloid characterization and TME measurements will be combined with modeling to decouple the impact of colloids from that of environmental factors, and thus achieve a more precise understanding of the behavior of colloids and associated TMEs in natural systems.

Activités

Carry out soil incubation experiments, perform chemical and isotopic analyses to characterize colloids and associated TMEs and trace soil-water transfer mechanisms, interpret data, and ultimately communicate results by writing scientific articles and taking part in conferences.

Compétences

Skills/knowledge: (Geo)chemist with solid experience in aqueous solution chemistry, colloids and isotopy.
Know-how: Use of analytical chemistry instruments, spectroscopy and geochemical speciation modeling tools.
Personal skills: Ability to work in a team and good communication skills in English (oral and written).

Contexte de travail

The project will take place within the Nanoscale team of UMR 6118 Géosciences Rennes (CNRS/Université de Rennes). The research activities of this team, created in January 2022, focus on determining and modeling the surface physicochemical properties of natural colloids and the associated contaminant transport processes, as well as the role of environmental conditions and biotic interactions on their fate. Most of the work will be carried out at the Nanoscale team laboratories, which have the necessary laboratory and analytical equipment to characterize colloids and analyze the associated trace metals. Main contacts: Nanoscale team (Géosciences Rennes)/Biogeochemistry of anthropocene emerging elements and contaminants team (IPGP).

Contraintes et risques

Work in a chemical laboratory in compliance with health and safety regulations.

All applicants must have spent at least 18 months abroad (outside France) between 1st May 2021 and the start of the project.

Informations complémentaires

Funding by Brittany Region: 'Bienvenüe' scheme for international post-doctoral researchers and ANR COLOSSAL project (https://anr.fr/Projet-ANR-23-CE01-0001)