Dissertation
Dissertation > Environmental science, safety science > The basic theory for the Environment and Science > Environmental Biology > Environmental botany

A Sudy of Ecological Toxicity Induced by Nano-Al2O3on Scenedesmus Obliquus

Author ZhuXing
Tutor YangXu
School Central China Normal University
Course Biochemistry and Molecular Biology
Keywords nano-Al2O3 Scenedesmus obliquus growth inhibition photosynthetictoxicity oxidative damage
CLC X173
Type Master's thesis
Year 2012
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In recent years, the rapid development of nanotechnology has brought significant impact to the world. Nanotechnology has become the basis of today’s high-tech and front area of the world. Due to the special nature of surface effect, small size effect and quantum size effect, nanoparticles (NPs) are very different from traditional materials, and they are widely used in various aspects of daily life. As a promising new material among them, nano-Al2O3closely contacts with daily life. The range of its applications is wide, such as engineering materials, optical materials, chemical materials, biological materials, refractory materials, magnetic materials, nuclear materials and so on. But in recent years, with nanotechnology industrialization and the emission of NPs into environment, ecological balance and stability have been broken, especially the water environment has been destroyed and polluted seriously. At present, some studies have already been taken on toxicological effect of NPs, but most of them are focused on C6o, SWCNT, MWCNT and other metal oxide (e.g. nano-ZnO, TiO2, SiO2). The toxicology effects of nano-Al2O3is of few data, especially its aquatic toxicological effect. Therefore, In order to study the environmental toxicity of nano-Al2O3, Scenedesmus obliquus was used to study the relationship between toxicity induced by nano-Al2O3and exposure concentration, time, from three aspects-growth inhibition effect, photosynthetic toxicity and oxidative damage. This preliminary data could be used to support a thorough ecological safety assessment of nano-Al2O3.According to the results of pre-experiment, final concentrations of nano-Al2O3were set to0,12.5,25,50,100mg/L. The results are as follows:1. The results of inhibition growth show that with nano-Al2O3concentration increased, cell numbers decreased, relative suppression rate increased, value of EC50decreased as nano-Al2O3exposure time increased. It suggested that nano-Al2O3could induce growth inhibition effect to Scenedesmus obliquus.2. The results of photosynthetic toxicity show that under high concentrations (≥50mg/L) of nano-Al2O3exposure, photosynthetic pigment contents decreased, absorption spectrum changed with no absorption peak in the visible region, the absorption of CO2decreased, net photosynthetic rate decreased. It suggested that when reaches a certain concentration (≥50mg/L), nano-Al2O3could induce photosynthetic toxicity to Scenedesmus obliquus.3. The results of oxidative damage show that under high concentrations (≥50mg/L) of nano-Al2O3exposure,· O2-and H2O2contents increased, SOD, CAT and POD activities decreased, MDA content increased, It suggested that when reaches a certain concentration (≥50mg/L), nano-Al2O3could induce oxidative damage to Scenedesmus obliquus.All the results show that, when reaches a certain concentration (≥50mg/L), nano-Al2O3could induce ecological toxicity to Scenedesmus obliquus.

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