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Communication Dans Un Congrès Année : 2012

Chronic ecotoxicity of ceria nanoparticles on freshwater micro-invertebrates

Xavier Moreau
Laetitia de Jong

Résumé

Nanoparticles are more and more incorporated in commercial products. It is consequently inevitable that a large amount of NPs will be discharged into environment, underlining the need to evaluate the ecotoxicological effects of NPs. Although there is some evidence for adverse effects on aquatic organisms, there is still a lack of consistency in nanoecotoxicity investigations likely due to differences in the physico-chemical parameters of the tested NPs or in the way the NP suspensions were dispersed. Furthermore, most of the available data are still related to acute toxicity after exposure at concentrations exceeding those predicted to occur in the environment. In that context, our work aimed at assessing the chronic effect on freshwater micro-invertebrates exposed to sublethal concentrations of different ceria NPs in suspension (ie. a 25 nm and a 10 nm primary particle size NPs). The selection of ceria NPs was motivated by their growing commercial use in number of applications such as outdoor paints or as fuels catalyst for which release to aquatic compartment is therefore expected. Besides, ceria NPs are also one of the selected NPs for priority testing by the OECD. Chronic ecotoxicity was investigated on C. dubia following the standardized methods (ISO 20665). After 8 days of exposure, a dose-dependent inhibition of growth and reproduction of daphnids were reported for both ceria NP tested (10 nm and 25 nm). Interestingly, the 10 nm nCeO2 induced higher toxicity than the 25 nm nCeO2. We reported EC50 values from 5.7 to 15.7 mg/L depending on the method used to disperse the 25 nm ceria suspensions, whereas EC50 from 1.2 to 1.6 mg/L were recorded after exposure to the 10 nm ceria suspensions. This result highlights that the primary particle size is an important parameter when focusing on nCeO2 ecotoxicity. The influence of the dispersive methods on the ecotoxicity towards micro-invertebrates will also be discussed. In addition to these results, histological and ultrastructural investigations of target cells in C. dubia (i.e. midgut epithelium) were performed by TEM. The results obtained have clearly shown that the ceria NPs were present in the digestive tract lumen of C. dubia. Disappearance of the apical microvilosities of intestinal cells and reduction of rough endoplasmic reticulum network were observed. These ultrastructural damages are sufficient to disturb cellular metabolisms such as nutrient absorption, protein synthesis or phospholipid assemblage.
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Dates et versions

ineris-00970981 , version 1 (02-04-2014)

Identifiants

  • HAL Id : ineris-00970981 , version 1
  • INERIS : EN-2012-171

Citer

Nicolas Manier, Xavier Moreau, Laetitia de Jong, Pascal Pandard. Chronic ecotoxicity of ceria nanoparticles on freshwater micro-invertebrates. 6. SETAC World Congress 2012 / 22. SETAC Europe Annual Meeting "Securing a sustainable future : integrating science, policy and people", May 2012, Berlin, Germany. ⟨ineris-00970981⟩

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