Research On The Toxicological Effects Of Nano-titanium Dioxide（TiO₂） To Aquatic Organisms

Nano-sized TiO₂ began to be manufactured in the 20 th century.Because of its unique optical、surface hydrophilic effect and UV absorber.Nano-sized TiO₂ was widely used in various fields of paints,cosmetics,sewage purification and and environmental sectors.With the continuous improvement and development of nanotechnology,TiO₂ gradually integrated into people’s daily lives through a variety of ways and means.It gave convenience,but also brought risk directly or indirectly to human and their living environment.water environment which was the inseparable environment to human production and lives.Studying the behavior of the water environment and its impact to aquatic organisms had great significance.Meanwhile,it also provided a scientific basis on the effects of TiO₂ to biological organisms and environmental risk.Chlorella,Daphnia magna and zebrafish were experimental biologies,they were applied in the three steps of experiments and studies on effects of TiO₂ to aquatic organisms.The results of Chlorella worked that it was inhibited by TiO₂ through the determination of biological macromolecules and enzymes.TiO₂ showed the effects of suppression after promotion.Daphnia magna was used to compare the toxicity at the effects of nTiO₂ and micro titanium dioxide（μTiO₂）.It showed that the biological toxicity of nTiO₂ was stronger thanμTiO₂ in the water on the growth and reproduction to Daphnia magna.Chronic test futher showed that their inhibition effect obviously depended on doses,and also time.Time factor was a very important influence factor.At the low concentration,with the time added,the adverse effects on the growth and reproduction of Daphnia magna was tested.The zebrafish accumulation experiment showed that TiO₂ could be accumulated in zebrafish.It made very significant of the volume to the different parts of zebrafish.In this experiment,visceral had the max-accumulation.micronucleus test and comet assay detected based the molecular level.It showed that TiO₂ had effects to zebrafish,but no significant effect below 80mg/L.All the experiments implied that TiO₂ defined as acute 3 and chronic 2.