CLIMETAL · Impact of metal pollution on freshwater ecosystems submitted to extreme climate events

Freshwaters simultaneously receive a high diversity of contaminants, metals being amongst the most toxic. The growing use of metals for energy transition (e.g. electric vehicles, wind turbines, solar panels) is exposing freshwater ecosystems to unknown threats. These also suffer from the increasing frequency and intensity of extreme climate events (i.e. droughts and floods), which may cause hydric stress, physical abrasion, lower dilution, or contaminant pulses. These overall influence metal bioavailability and expose the biota to unknown toxicological effects. CLIMETAL will address these challenges by exploring the fate of metals used in energy transition, including those with understudied toxicity (lithium, rare earth elements, etc.), as well as their separated and sequential biological effects under the hydrological alterations associated to droughts and floods. CLIMETAL will investigate the influence of these alterations on metal bioavailability, and the subsequent consequences for their bioaccumulation and ecotoxicological effects. Bioavailability of metals will be estimated by modelling their chemical speciation and by measuring their labile concentrations, giving rise to a collaboration with physical chemists (= secondment). Metal bioaccumulation as well as biological and functional effects on freshwater ecosystems will be assessed using primary producers (biofilms) and primary consumers (invertebrates). These two biological compartments are connected and provide a complementary response to the metal exposure under distinct hydrological alterations. The proposal adopts an interdisciplinary approach involving ecotoxicology, environmental chemistry, ecology and modelling and combines complementary methods from laboratory (microscosm, mesocosm) to fieldwork. Data generated in CLIMETAL will contribute to fulfill the European Green Deal, which aims to reduce the impact of climate change and environmental pollution as well as protect ecosystems.