Study On The Toxicity Of Nanoparticles And Heavy Metal To Escherichia Coli In Aquatic Enviroment

Nanotechnology products,Will inevitably enter the environment through various means During the production, utilization and disposal.Its special physical and chemical properties may bring unpredictable effects to the environment.While in natural water environments, Nanoparticles always coexist with other pollutants and affect each other, enhance or diminish aquatic toxicity of pollutants. The study choosed E. coli as objects to determine toxicity of two kinds of nanoparticles and cadmium to Clarify the mechanisms of effects of complex toxic pollution on E. coli.(1) The main results were following: Studying the adsorption properties of nano-TiO2 and nano-ZnO to heavy metals Cd(II) in different water, showed that: the adsorption capacity of two nano-particles were reduced with water hadness increaring because of ionic strengths increased to promote the particles gathering..But the test results showed that with the increase in water hardness concentration of heavy metals Cd(II) was decreased. It was speculated that this may be due to Cd(II) the combination with r sulfate(SO42-), carbonate(CO32-), the content of bicarbonate(HCO3-) plasma in water with hadness increaring.(2) by Study on the affects of nanoparticles to Escherichia coli in ultrapure environment found that bacterial death rate of nano-ZnO particles was higher than the nano-TiO2 particles and it was up to 97.95% at a concentration of 100mg/L and also found Nano-ZnO filtrate was toxic, but the nano-TiO2 filtrate had no obvious toxicity.(3) The experiment to Clear the impacts of TiO2 and ZnO nanoparticles with heavy metal ions on bacteria in different water quality to Clarify the mechanisms of effects of complex toxic pollution on the bacteria was did. The test results showed that E. Coli’s fatality rate was reduced with hardness of water increased. It wasprobably because the concentration of heavy metal ions were reduced by the combination with carbonate(CO32-), the content of bicarbonate(HCO3-) plasma in water and TiO2 and ZnO nanoparticles contact with E. coli was reduced due to the adsorption capacity reduced with water hadness increaring because of ionic strengths increased to promote the particles gathering.