Study On The Biological Effects Of Carbon-based Nanomaterials On Different Model Organisms

Nowadays,nano materials have been widely used in daily life,industrial and agricultural production,and will inevitably be discharged into the water environment,which will have a certain impact on aquatic organisms,while the heavy metal cadmium?Cd?harm to aquatic organisms has caused wide public concern,the coexistence of both how to impact on aquatic organisms.In agriculture,the application of nano-fertilizers can not only improve the soil and promote the increase of crop yield,but also affect the nutritional components of crops,or even cause harm to human body by transferring the residues in crops to human body through the food chain.Therefore,this subject will conduct research on the above issues,the specific research content is as follows:In the first study,three graphene family materials?GFMs?such as graphene?G?,graphene oxide?GO?and aminated graphene?GNH?and heavy metal Cd were selected as research objects,and Scenedesmus obliquus?S.obliquus?was selected as the test organisms,using cell growth inhibition rate,chlorophyll a synthesis inhibition rate,cell membrane integrity loss degree,mitochondrial membrane potential and ROS activity level as toxicity indicators,compare the toxicity and differences of these three GFMs on Cd to S.obliquus;at the same time,in order to explore the toxicity mechanism of Cd to S.obliquus in the presence of GFMs,the surface functional groups of GFMs and the morphological changes of the cell surface and oxidative stress in the cells were characterized.In the second study,TiO₂ NPs,CuO NPs and biochar?BC?were selected as the research objects.Purple leaf lettuce was the tested organism.The biological effects of the mixed nanoparticles?NPs?and individual nanoparticles in the growth process of lettuce seedlings were studied.The fresh weight,chlorophyll?Chla,Chlb?content,soluble sugar content,nitrate nitrogen content,ROS activity and CAT activity of lettuce seedlings were mainly studied.At the same time,in order to further explore the mechanism of nanoparticles on lettuce seedling growth,ICP-MS and SP-ICP-MS were used quantitatively characterize the metal content and the number of nanoparticles in different parts of lettuce seedlings.Our research results show that Research One:the influence of GFMs on the acute toxicity of Cd to S.obliquus is in the order of GO>G>GNH based on their EC₅₀ of Cd-GFMs.The effects of GFMs on the cytotoxicity and oxidative damage of Cd to S.obliquus are varied with the concentrations of GFMs.The differences between the effects of GFMs on Cd toxicity may attribute to their different surface oxygen-containing functional groups contained in the nanomaterials.The adsorption capacity of nanomaterials on metal ions,their dispersibility in water and their interaction mode with organisms,may dominate main contributions to their effects on Cd toxicity.Research Two:Our results showed that both individual TiO₂ NPs and CuO NPs at 10 mg/L caused oxidative damage to lettuce,eventhough TiO₂ NPs promote the lettuce's fresh production and nutrition,while CuO NPs mitigated the fresh weight.The biologic effects of metallic oxide NPs applied in BC-amended soil on lettuce seedlings are somewhat complex.Further,the translocation of NPs measured with ICP-MS measurement showed the total Ti or Cu in the shoots and roots of lettuce increased with the dosage of TiO₂NPs or CuO NPs.The quantitative analysis of NPs inside the lettuce characterized with SP-ICP-MS showed that the distribution and content of NPs varied with the parts of lettuce.Our study aids to clarify the interference of NPs on the ecotoxicity of metals,to avoid the misunderstanding of the potential risk of metals in the complicate water environments;it aids to clarify the impact of nanomaterials on agricultural crops,further,to illuminate the possible human health risk quantitatively through food consumption.