The Laboratoire Interdiciplinaire des Environnements Contimentaux (LIEC) and Mer Molecules Santé (MMS) are offering a post-doc position in the framework of a newly funded international project on the ecotoxicology of Rare Earth Elements in aquatic systems (ECOTREE) and within the framework of Labex Ressources 21 (www.univ-lorraine.fr/labex-ressources-21)
Fixed term contract 18 months(12 months LIEC, Université de Lorraine,
Nancy and 6 months MMS, Angers, France)
) is funded in the framework of the International and Collaborative Research Program between national research funds from France and Luxembourg. ECOTREE is a truly interdisciplinary project, covering large parts of the REE life cycle, from anthropogenic REE geochemistry, REE dynamics in (waste)water systems, REE speciation and related bioavailability, to REE trophic transfer and environmental impact assessment at different biological levels - all of this from a Life Cycle Assessment perspective. The project stands as a milestone towards the ecotoxicological and mechanistic understanding of REEs in freshwater ecosystems and will help to define appropriate strategies for a better assessment and management of the predicted increase in their environmental concentrations.
The proposed position spans from research on the partitioning and speciation of REE in wastewater, surface water and experimental ecotoxicological media to their subcellular partitioning in biota.
The partitioning and speciation of REEs largely determines their fate, solubility , bio-availability and toxicity towards biota. Until now the processes governing the speciation of REEs being adsorption to organic matter and mineral phases has been mainly studied for purified or synthesized laboratory model systems. In this project we aim to measure the partitioning in wastewater and surface water and study the specific characteristics of the most important phases important for interaction with REEs for the different systems. Measurements will be combined with geochemical modelling for interpretation of the results.
Since the accumulation and detoxification of metals in organism cells can involve their binding to both soluble and insoluble subcellular components, a compartmentalization procedure will be used to determine the binding of REE to these two fractions in aquatic organisms. Then, to deal with the subcellular REE distribution in depth and its biological significance, a subcellular fractionation (metal-rich granules, cellular debris, organelles, metallothionein-like proteins, and heat-sensitive proteins) will be performed in few individuals of organisms on organs involved in metal metabolism (digestive gland or liver).Description:
The processes determining the solid solution partitioning of REEs in wastewater and river water will be studied by a combination of experimental methods and geochemical modelling. Solid solution partitioning will be determined using filtration/ultrafiltration. Speciation in the solution phase will be determined using the Donnan Membrane Technique (DMT). Important reactive surfaces for the binding of REEs will be determined and characterised using selective chemical extractions, spectroscopic techniques and by fractionation of the organic material (humic acids, fulvic acids, hydrophilic fraction). This information will be used to model the partitioning and speciation using a mechanistic geochemical multi-surface model (ORCHESTRA).
Determination of the binding of REEs to a standard fulvic acid and the derivation of specific NICA-Donnan model parameters for REE binding. The standard fulvic acid will be used in ecotox and mesocosm studies in the project.
A compartmentalization procedure will be used to determine the binding of REEs to soluble and insoluble fractions in aquatic organisms followed by a subcellular fractionation in few individuals of organisms on organs involved in metal metabolism (digestive gland or liver). REE concentrations in these different fractions will be quantified by ICP-MS. These sub-cellular fractionation approaches will be combined with synchrotron techniques to fully understand cell partitioning and speciation of contaminants and how accumulation relates to toxic effects.
In the framework of the ECOTREE project, this position will be complemented at LIEC and the Luxembourg Institute of Science and Technology (LIST) by two additional positions: One PhD project (LIEC) will focus on the "Origin, behaviour and fate of Rare Earth Elements in wastewater treatment plants and receiving river water"; an additional post-doctoral position at LIST, which focusses at "The hydro-geochemical dynamics of REEs in contaminated river basins".Profile
- PhD degree in environmental sciences with focus on trace element behaviour in natural systems (water, sediment, soil)
- Strong experience in laboratory work
- Experience with chemical speciation modelling and ecotoxicology is favourable
- Strong scientific writing skills as demonstrated with international scientific publications
- Excellent skills in speaking, reading and writing English
- Knowledge of French language is appreciated but not mandatory
is a research unit under the joint co-ordination of the Université de Lorraine and of the CNRS. It has about 90 permanent employees with expertise in ecology, ecotoxicology, microbiology and physico-chemistry of anthropised ecosystems. Its main research missions include fate and effects of contaminants in terrestrial and freshwater environments.
Major ongoing projects span from the functioning of ecosystem (ANR Functional Streams), the mobility and behaviour of sediment-bound contaminants during high-flow events (ANR Mobised, international project in partnership avec Luxembourg), the response of organisms to nanomaterials along a freshwater-saltwater continuum (ANR Nanosalt), the study of the combined effect of multiple stressors onto ecosystems functioning (ANR Multistress) and the interaction between pollution and climate change (ANR IPOC in cooperation with Canada). A series of more focussed projects are running on specific aspects related to similar issues.Mer Molécules Santé
is a Pays de Loire research team belonging to the CNRS-Research
Federation "Institut Universitaire de la Mer et du Littoral". The unifying theme of MMS is the study of coastal marine food webs, to contribute to an integrated and sustainable management of these ecosystems through knowledge of their biodiversity but also to identify the organisms or metabolites of interest to human health.
The research works in aquatic ecotoxicology in MMS are nationally and internationally recognized with an expertise on the ecotoxicity (chemical speciation, tolerance, detoxification processes, biochemical responses) of metals and emerging contaminants (e.g; nanomaterials) in different aquatic species representing different trophic levels. The "aquatic ecotoxicology" team combines multidisciplinary skills including researchers in the fields of chemistry, ecology and ecotoxicology and represents 14 permanent members (2 fullprofessors, 8 Associate-professors, 2 researchers, 2 technicians), 4 PhD students.
Supervising scientists: J.E. (Bert-Jan) GROENENBERG (LIEC) and A. (Amélie) CHATEL (MMS)