Abstract:
Titanium dioxide (TiO2) nanoparticles have a wide range of use in various commercial products. Such widespread use of nano sized TiO2 could lead to significant release of nano-TiO2 into the environment leading to a potential threat for their increased environmental concentrations. Fish occur at the top of food chain hierarchy in aquatic environment and is valuable bio-monitor of aquatic pollution. In the present study, grass carp (Ctenopharyngodonidella) was used as bioindicator for the toxicity potential of nano-TiO2. The effects were based on acute, sublethal toxicity. Two doses of 1.5 and 3.0 μg of nano- TiO2 and fine particles of titanium dioxide used as negative control. The exposure periods for the study were 24, 48 and 72 h. Genotoxic effects analyzed through comet assay, suggested morphological changes in erythrocyte nuclei. Nuclear abnormalities including blebbed, segmented and mironulei were observed. The DNA damage was approximately 90 % for nano-TiO2 exposed group. Nitroblue tetrazolium (NBT) reduction assay for determination of immunological changes provided a clear evidence for increase in reactive oxygen species (ROS) production triggered by the nanoparticles. ROS concentration had reached nearly 50 % at 72 h exposure to nanoparticles. The results suggested a positive correlation (r= 0.7791, 0.7891) between increase in ROS production and DNA damage
