Toxicity of CeO2 nanoparticles at different trophic levels – Effects on diatoms, chironomids and amphibians
2015
Bour, Agathe | Mouchet, Florence | Verneuil, Laurent | Evariste, Lauris | Silvestre, Jérôme | Pinelli, Eric | Gauthier, Laury
The aim of the present work is to provide wider information on the toxicity of cerium dioxide nanoparticles (CeO2 NPs) in aquatic environments, by studying the toxicity of two types of CeO2 NPs for four species (diatoms Nitzschia palea, the sediment-dwelling invertebrate Chironomus riparius, and the amphibian larvae Xenopus laevis and Pleurodeles waltl.). The two types of CeO2 NPs have different intrinsic properties: some of them are small citrate-coated spheres (2–5nm), and the others are larger uncoated plates (20–60nm). Acute toxicity (mortality at 48 or 96h, depending on the test-organism) was assessed for the four species, from 0.1 to 100mgL−1 of NPs. Sub-lethal effects were assessed on chironomids exposed between 0.01 and 1mgL−1 of NPs. Mortality, growth inhibition and genotoxic effects were evaluated on amphibian larvae from 0.1 to 10mgL−1. Results reveal that no acute toxicity occurs on any species after short exposures, even at the highest concentrations. Mortality (35%) is observed on Xenopus larvae after 12d of exposure at the highest concentration of one type of NPs. No significant effects were observed on chironomids during chronic exposure. Xenopus larvae growth was inhibited from 1mgL−1 of both NPs while growth inhibition is observed on Pleurodeles only at the highest concentration of one type of NPs. No genotoxicity was observed on Xenopus but Pleurodeles exhibited dose-dependent genotoxic effects when exposed to one type of NPs. Observed differences in toxicity are discussed focusing on the studied compartment, routes of exposure, species and NPs.
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