Exposure to cerium dioxide nanoparticles differently affect swimming performance and survival in two daphnid species

The CeO2 NPs are increasingly used in industry but the environmental release of these NPs and their subsequent behavior and biological effects are currently unclear. This study evaluates for the first time the effects of CeO2 NPs on the survival and the swimming performance of two cladoceran species, Daphnia similis and Daphnia pulex after 1, 10 and 100 mg.L(-1) CeO2 exposures for 48 h. Acute toxicity bioassays were performed to determine EC50 of exposed daphnids. Video-recorded swimming behavior of both daphnids was used to measure swimming speeds after various exposures to aggregated CeO2 NPs. The acute ecotoxicity showed that D. similis is 350 times more sensitive to CeO2 NPs than D. pulex, showing 48-h EC50 of 0.26 mg.L(-1) and 91.79 mg.L(-1), respectively. Both species interacted with CeO2 NPs (adsorption), but much more strongly in the case of D. similis. Swimming velocities (SV) were differently and significantly affected by CeO2 NPs for both species. A 48-h exposure to 1 mg.L(-1) induced a decrease of 30% and 40% of the SV in D. pulex and D. similis, respectively. However at higher concentrations, the SV of D. similis was more impacted (60% off for 10 mg.L(-1) and 100 mg.L(-1)) than the one of D. pulex. These interspecific toxic effects of CeO2 NPs are explained by morphological variations such as the presence of reliefs on the cuticle and a longer distal spine in D. similis acting as traps for the CeO2 aggregates. In addition, D. similis has a mean SV double that of D. pulex and thus initially collides with twice more NPs aggregates. The ecotoxicological consequences on the behavior and physiology of a CeO2 NPs exposure in daphnids are discussed

Indoor mesocosms: an integrated approach to assess the environmental risks of nanomaterials

International audienc

Indoor mesocosms: an integrated approach to assess the environmental risks of nanomaterials

International audienc

Indoor mesocosms: an integrated approach to assess the environmental risks of nanomaterials

International audienc

An integrated approach to assess the environmental risks of nanomaterials

International audienc

An integrated approach to assess the environmental risks of nanomaterials

International audienc

Bringing environmental and historical archives together to analyze adaptation strategies of agropastoral systems vis-à-vis water stress in Central Asia

International audienceWhile some works have suggested that large-scale mobilities and conflicts in Central Asia and Western Asia (e.g. Mongol invasions) have been linked to climatic events, in this contribution we choose to move the focus to local human-climate interactions. We will specifically investigate what were the adaptation strategies of agropastoral systems vis-à-vis water stress, in the frame of various political constructions, over the last 1500 years. Based on palaeohydrological and paleoecological investigations carried out on selected lake sedimentary archives of Iran and Uzbekistan, we will reconstruct the long-term variability of lake evaporation and runoff processes (sedimentology, geochemistry), together with indicators on the nature and relative intensity of the agropastoral practices (palynology). Those results will be put into a Human perspective through comparisons with historical sources. In particular, we will propose a special focus on the Medieval Islamic Period to discuss the hypotheses that regional climate changes, by modifying water resource availability locally, might have impacted crops and pastoral livestock productions, triggering economic losses and social contestations unevenly addressed by the succeeding political powers

An integrated approach to assess the environmental risks of nanomaterials

International audienc

An integrated approach to assess the environmental risks of nanomaterials

International audienc

An integrated approach to assess the environmental risks of nanomaterials

International audienc