Does bioaccumulation in zebra mussels reflect the water chemical contamination ? Experiments Observations Modeling ; Bioaccumulation par Dreissena polymorpha: quel reflet de la contamination chimique du milieu ? Expérimentation Observation Modélisation

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA [Encadrant_IRSTEA]Gourlay, C. ; (trad auto)In the regulatory context of the Water Framework Directive, it is necessary to assess the impact of metal contamination on aquatic environments in order to establish a diagnosis of water bodies. Integrating the bioavailability of metals into this diagnosis by measuring bioaccumulation in model organisms makes it possible to more accurately assess the risk to the environment. However, the link between bioaccumulation and chemical contamination of the environment remains difficult to establish since it depends on physico-chemical and physiological parameters. In order to make this link in the zebra mussel, we used a kinetic model of bioaccumulation: the biodynamic model. Laboratory exposures investigated the influence of water physico-chemistry (calcium, zinc and dissolved organic matter concentration) on the accumulation constants of the dissolved model and developed an exposure protocol to determine trophic assimilation constants. The competitive effect of ions (Ca and Zn) on the accumulation of Cd and Ni by dissolved route was highlighted and integrated into the biodynamic model using an approach based on the biological ligand model (BLM). Contamination monitoring of transplanted dreissenes, over 2 months and 1 year, revealed the model's ability to link metal contamination of the medium to that of organisms, taking into account the physicochemistry of the medium (in particular the trophic level) and the physiology of the organism (filtration rate, growth rate). ; Dans le contexte réglementaire de la Directive Cadre sur l'Eau, il est nécessaire d'évaluer l'impact de la contamination métallique sur les milieux aquatiques pour pouvoir établir un diagnostic des masses d'eau. Intégrer dans ce diagnostic, la biodisponibilité des métaux par une mesure de la bioaccumulation dans des organismes modèles, permet d'évaluer plus finement le risque pour l'environnement. Cependant le lien entre la bioaccumulation et la contamination chimique ...