Résumé
The potential impact of industrial multiwalled carbon nanotubes (MWNTs) was investigated undernormalized laboratory conditions according to the International Standard micronucleus assay ISO 21427–1for 12 days of half-static exposure to 0.1, 1, 10 and 50 mg/l of MWNTs in water. Three different end pointswere carried out for 12 days of exposure: mortality, growth inhibition and micronuclei induction inerythrocytes of the circulating blood of larvae. Raman spectroscopy ana lysis was used to study the presenceof carbon nanotubes in the biological samples. Considering the high diversity of carbon nanotubesaccording to their different characteristics, MWNTs were analyzed in Xenopus larvae, comparatively todouble-walled carbon nanotubes used in a previous study in similar conditions. Growth inhibition in larvaeexposed to 50 mg/l of MWNTs was evidenced; however, no genetoxicity (micronucleus assay) was noticed,at any concentration. Carbon nanotube localization in the larvae leads to different possible hypothesis ofmechanisms explaining toxicity in Xenopus.