The increasing advance of nanotechnology has enabled the development of materials with optimized properties, including the production of nanostructured fertilizers as a more efficient alternative to replace conventional fertilizer aiming at increasing agribusiness production, including food and supplies. The use of these nanofertilizers also raise concerns about side effects caused by nanomaterials in the environment, which can impact aquatic biota and consequently the human health. Changes in the size and shape of the nanoparticles modify the way they interact with the environment, as well as inappropriate disposal and indiscriminate use of nanofertilizers can cause potential increase in the level of toxicity, especially for water resources, due to their greater vulnerability to environment contamination. In this context, the present study aims at synthesize and characterize, by several physic-chemical techniques, nanofertilizers based on zinc oxide (ZnO) and hydroxyapatite Ca10(PO4)6(OH)2 (HAP), and evaluate nanotoxicity of these materials for the specie of microalgae Pseudokirchneriella subcapitata, since microalgae form the base of the aquatic trophic chain. The synthesis of ZnO nanoparticles and HAP will be carried out by hidrothermalization and coprecipitation methods in order to control the formation of phases and the particle size. Subsequently we will use microscopy scanning electron (SEM), X-ray diffraction (XRD), zeta potential and isotherms adsorption / desorption of N2 for structural and morphological characterization. Bioassays chronic toxicity to microalgae will be carried out to evaluate the inhibition of growth and morphological changes when exposed to nanoparticles.
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