Assessing the toxicity of gadolinium in freshwater and marine ecosystems: Effects across trophic levels.

Rare Earth Elements, particularly gadolinium (Gd), are increasingly used in industrial and medical applications, leading to their dispersion in aquatic environments. This study examines the ecotoxicological effects of Gd on aquatic organisms across different trophic levels in freshwater and marine ecosystems. Using standardized bioassays, the impact of Gd was assessed on Aliivibrio fischeri, Raphidocelis subcapitata, Phaeodactylum tricornutum, Daphnia magna, and Paracentrotus lividus larvae. Results showed that primary producers exhibited the highest sensitivity, with growth inhibition at low concentrations. In contrast, primary consumers (D. magna and P. lividus) were less affected by Gd, displaying a higher tolerance to its toxic effects even at elevated concentrations. Principal component analysis highlighted distinct responses between freshwater and marine organisms, suggesting a complex relationship between Gd bioavailability and toxicity. Hence, Gd contamination poses ecological risks requiring further research on its environmental impact.