Evaluation of copper oxide nanoparticle toxicity to cyanobacteria Anabaena sp. in Guilan wetlands

Since nanoparticles cause increase of serious threat to human, animals and aquatic ecosystems, toxicity of copper oxide nanoparticles (CuO-NPs) on cyanobacteria Anabaena sp. in different concentrations were studied using growth inhibition test (OECD201). The negative Zander cyanobacteria were grown in the culture medium (Z-8-N) under optimum conditions of light, temperature and aeration in growth chamber. After starting the logarithmic growth phase, samples were exposed to various concentrations of copper oxide nanoparticles at intervals of 24, 48 and 72 hours. The number of cyanobacterial cells was daily counted and analyzed based on Probit analysis. The effective concentration (EC50), no effect concentration (NOEC), specific growth rate (μ), doubling time (G), percentage growth inhibition (I%) and chlorophyll content was calculated. Treatments and control were significantly different in terms of cell density and growth inhibition percentage at specific intervals. In addition, the chlorophyll content of different treatments showed significant difference compared to control. It seems reducing the efficiency of photosynthesis is one of the routes that lead to considerable damage of copper oxide nanoparticles on Anabaena sp.