Avis d'expert en biologie environnementale

Investigating the Uptake and Some Subcellular Effects of Manufactured Goethite Nanoparticles on Lumbriculus variegatus

Julián Gigena, María L Martínez, Gonzalo M Zbihlei, Patricia Bozzano, Paula R Alonso, Adriana C Cochón and Noemí R Verrengia Guerrero

Investigating the Uptake and Some Subcellular Effects of Manufactured Goethite Nanoparticles on Lumbriculus variegatus

The aims of this work were: 1) to investigate whether the freshwater oligochaete Lumbriculus variegatus incorporates manufactured goethite nanoparticles (NPs) after an acute exposure; 2) to evaluate the influence of a solution of humic acids (HA) on the uptake of NPs; 3) to investigate the effects of these NPs on several biomarkers related to the generation of reactive oxygen species (ROS). NPs were analyzed by transmission electron microscopy. To evaluate the uptake, animals were exposed to 10 mg NPs L-1 for 48 h and then depurated for different periods (0;4;16, and 24 h). Iron concentrations were measured by atomic absorption spectrophotometry. Biomarker parameters were determined in oligochaetes exposed to a suspension containing 10 mg NPs L-1 for 48 h without depuration. Oligochaetes depurated for 4 h presented higher levels of Fe in their whole body tissues than control organisms. However, values returned to control levels when the oligochaetes were depurated for periods longer than 16 h, suggesting that organisms may transitorily incorporate the NPs in their digestive tract and/or superficially adsorbed them but they could not absorb the NPs. Exposures for periods longer than 48 h did not increase the Fe body burden. The presence of a 20 mg L-1 of humic acid solution prevented the NPs uptake. Several biomarker parameters related to the generation of reactive oxygen species were assessed. The activity of the enzyme superoxide dismutase and levels of total glutathione were higher in animals exposed to the NPs for 48 h than in controls. However, the catalase activity and the determination of the total scavenger capacity (TOSC assay) were not modified.The release of manufactured nanomaterials to the aquatic environment may elicit some subcellular responses even when the NPs are not absorbed by the organisms.