LANTHANIDES EFFECTS ACROSS Daphnia magna GENERATIONS

The applications in technologies of lanthanides, as Cerium and Erbium, have made them as emergent contaminants with a toxic impact on environment. Recent literature, highlights their ecotoxicity, bioaccumulation and action in order to predict the possible environmental risks. Few studies focused on the toxicity effects linked to their intracellular concentration on Daphnia magna1-3 wich is an excellent biomonitoring aquatic species4. To date, ecotoxicological experiments based on multi-generational field exposures are still little considered. In this study, chronic multigenerational effects on D. magna were assessed using various exposure times (3, 7, 14, and 21 days) in three generations (F0, F1 and F2). Each generation was exposed to environmental concentrations of Ce (0.54 μg/L ) and Er (0.43 μg/L) and the effects included: organisms’ size, reproduction, survival, ROS determination, activity of SOD, CAT and GST, expression of ABC transporter5, and uptake. Results evidenced that chronic multi-generational exposure of daphnids reduced survival, growth and reproduction, increasing ROS, SOD and CAT from F0 to F2. Ce reduced the number of offsprings after each generation, while Er delayed the time of offspring emergence, but not their number. ROS, SOD, CAT and GST evidenced that Er is slightly more toxic than Ce. Up- and downregulation of genes was limited, but Ce and Er activated the ABC transporters. Their uptake decreased through exposure time and generations.