Nanoecotoxicity of phyco-biogenic magnetic iron oxide nanoparticles in embryos and larval stages of zebrafish (Danio rerio)

In order to predict the environmental effect of biosynthesized magnetic iron oxide nanoparticles (magnetite or bio-Fe3O4) using marine green algae Ulva flexuosa in aquatic ecosystems, its toxicity was assessed on the early life stages and larvae of zebrafish, Danio rerio as an aquatic model. For this purpose, 10 fertilized eggs of zebrafish were exposed to serial concentrations of bio-Fe3O4 nanoparticles (0, 10, 50, 100, 200 and 500 mg/L) in 6 well plates in 6 replicates. After 12, 48, 72, 96, 110 and 134h samples were assessed. Results showed that the percentage of hatching rate and the larval survival rate decreased with increasing exposure time and concentration of magnetite nanoparticles (P<0.05). After 48h of exposure, in the highest concentration (500mg/L), the hatching rate of fish decreased to 36.6% (48 h LC50 = 638.2 mg/L) and after 134h of experimental periods, the survival rate of larvae reached to 43.3% (134 h LC50 = 645.4mg/L). The mean of all skeletal malformations in zebrafish would be significant with an increase in a dose- and time-dependent pattern during the exposure to nanoparticles and in the highest dose (500mg/L) reached 13.3% (P<0.05). It seems that the toxicity of bio-Fe3O4 nanoparticles affected by their particle size (13.8nm) and potentially toxic kinetic actions of particles at the nanoscale.