Évaluation de risques environnementaux de micro et macroplastiques en interaction avec des nanoparticules métalliques ou du cadmium sur les organismes aquatiques.

This study aims to understand the ecotoxicological mechanisms associated with pollution in estuarine and coastal environments, in a context where marine pollution, particularly plastic pollution, is a real environmental, health and social issue. The originality of this work lies in the analysis of interactions between different pollutants (heavy metals, metallic nanoparticles, microplastics, biodegradable plastics) and marine organisms: M. gigas (filter-feeding bivalve), T. isochrysis and P. tricornutum (phytoplankton). The processes of transformation, adsorption, trophic transfer and toxicity were studied under realistic environmental conditions. The results revealed that PBAT degradation products bind to cadmium, reducing its bioavailability and toxicity, including within food chains. The physiological and morphological responses observed in the two microalgae studied confirm the induction of oxidative stress in the presence of the studied pollutants. Exposure measurements reveal that contamination can be transmitted via the food chain, highlighting its potential implications for human health as part of the “One Health” approach. Finally, the innovative protocols developed enable dose-response relationships to be reconstructed despite the absence of pollution-free control environments. New and robust scientific information is provided on the fate and impact of pollutants in coastal environments. They underline theimportance of considering their life cycle when assessing biological risks.