Effect of zinc-selenium nanoparticles on microalgae scenedesmus quadricauda

Abstract

The increasing industrial use of nanomaterials in recent years poses a potential risk to the environment. The first organisms that come into contact with these substances include aquatic organisms, and therefore this study focuses on microalgae that are at the beginning of the food chain. In this study, the toxicity of ZnSe nanoparticles in the freshwater green microalga Scenedesmus quadricauda was investigated. The effect of zinc in the form of zinc sulphate heptahydrate (ZnSO4.7H2O) and the combination of zinc and nanoparticles were also monitored. The microalgae were exposed to these nanoparticles at concentrations of 10, 50, 100 and 250 M for 7 days. The microalgae responses were analyzed at the level of chlorophyll-a, chlorophyll-b, carotenoids, flavonoids and total antioxidant capacity. For chlorophyll-a, -b and carotenoids, similar results were obtained. The most significant effect was found in the sample with a combination of zinc and ZnSe nanoparticles. This sample also affected the most the flavonoid content, especially at concentrations of 50, 100 and 250 M, where increased synthesis of these compounds was observed. Similar results were obtained in the total antioxidant capacity assay, where a sample with combination of zinc and ZnSe nanoparticles showing an increasing trend, particularly at a concentration of 250 M.