title: Toxicity of CeO₂ nanoparticles on a freshwater experimental trophic chain: A study in environmentally relevant conditions through the use of mesocosms.
abstract: The toxicity of CeO2 NPs on an experimental freshwater ecosystem was studied in mesocosm, with a focus being placed on the higher trophic level, i.e. the carnivorous amphibian species Pleurodeles waltl. The system comprised species at three trophic levels: (i) bacteria, fungi and diatoms, (ii) Chironomus riparius larvae as primary consumers and (iii) Pleurodeles larvae as secondary consumers. NP contamination consisted of repeated additions of CeO2 NPs over 4 weeks, to obtain a final concentration of 1 mg/L. NPs were found to settle and accumulate in the sediment. No effects were observed on litter decomposition or associated fungal biomass. Changes in bacterial communities were observed from the third week of NP contamination. Morphological changes in CeO2 NPs were observed at the end of the experiment. No toxicity was recorded in chironomids, despite substantial NP accumulation (265.8 ± 14.1 mg Ce/kg). Mortality (35.3 ± 6.8%) and a mean Ce concentration of 13.5 ± 3.9 mg/kg were reported for Pleurodeles. Parallel experiments were performed on Pleurodeles to determine toxicity pathways: no toxicity was observed by direct or dietary exposures, although Ce concentrations almost reached 100 mg/kg. In view of these results, various toxicity mechanisms are proposed and discussed. The toxicity observed on Pleurodeles in mesocosm may be indirect, due to microorganism's interaction with CeO2 NPs, or NP dissolution could have occurred in mesocosm due to the structural complexity of the biological environment, resulting in toxicity to Pleurodeles. This study strongly supports the importance of ecotoxicological assessment of NPs under environmentally relevant conditions, using complex biological systems.
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Agathe
authors.initials: A
authors.lastname: Bour
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Florence
authors.initials: F
authors.lastname: Mouchet
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Cadarsi
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Jérôme
authors.initials: J
authors.lastname: Silvestre
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Laurent
authors.initials: L
authors.lastname: Verneuil
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .
authors.forename: David
authors.initials: D
authors.lastname: Baqué
authors.affiliation: c CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , Toulouse , France .
authors.forename: Eric
authors.initials: E
authors.lastname: Chauvet
authors.affiliation: b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .|d Laboratoire de Radioécologie et d'Ecotoxicologie , IRSN (Institut de Radioprotection et de Sûreté Nucléaire), DEI/SECRE , Cadarache , France .
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Bonzom
authors.affiliation: b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .|e CNRS, Université de Lorraine, LIEC (Laboratoire Interdisciplinaire des Environnements Continentaux) UMR 7360, Metz, France .
authors.forename: Christophe
authors.initials: C
authors.lastname: Pagnout
authors.affiliation: b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .|e CNRS, Université de Lorraine, LIEC (Laboratoire Interdisciplinaire des Environnements Continentaux) UMR 7360, Metz, France .
authors.forename: Hugues
authors.initials: H
authors.lastname: Clivot
authors.affiliation: f CMEAB (Centre de Microscopie Electronique Appliqué à la Biologie), Université Paul Sabatier, Faculté de Médecine Rangueil , Toulouse , France , and.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Fourquaux
authors.affiliation: b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .|g CNRS, Université d'Aix-Marseille, CEREGE UMR 7330 , Aix-en-Provence , France.
authors.forename: Marie
authors.initials: M
authors.lastname: Tella
authors.affiliation: b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .|g CNRS, Université d'Aix-Marseille, CEREGE UMR 7330 , Aix-en-Provence , France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Auffan
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Laury
authors.initials: L
authors.lastname: Gauthier
authors.affiliation: a CNRS, Université de Toulouse, INP, UPS, EcoLab (Laboratoire d'écologie fonctionnelle et environnement) UMR 5245 , ENSAT, Avenue de l'Agrobiopole , Castanet Tolosan , France .|b International Consortium for the Environmental Implications of Nanotechnology (iCEINT) , Aix-en-Provence , France .
authors.forename: Eric
authors.initials: E
authors.lastname: Pinelli
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects; D018533:Biomass; D002563:Cerium / Q000737:chemistry / Q000633:toxicity*; D002683:Chironomidae / Q000187:drug effects; D017377:Diatoms / Q000187:drug effects; D054750:Ecotoxicology / Q000379:methods*; D020387:Food Chain; D005618:Fresh Water / Q000382:microbiology*; D005658:Fungi / Q000187:drug effects; D007814:Larva / Q000187:drug effects; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D010999:Pleurodeles
chemical_list: D002563:Cerium; C030583:ceric oxide
keywords: Amphibian; chironomidae; ecotoxicity; litter decomposition; microorganisms