Toxic effect of nano and bulk TiO2 on growth, chlorophyll a content and oxidative stress of marine diatom Chaetoceros muelleri

Nanoparticles are widely used in many applications. The recent increase in nanomaterials usage has led to raising concerns about its health risks and environmental impact. In this study, we examined the toxicity effects of nanoparticles TiO 2 and bulk Ti on marine diatom chatetoceros muelleri. We treated microalgae with equal amounts of nano and bulk TiO 2 in different concentrations include 0, 10, 50, 100, 200 and 300 ppm, then was investigated their growth in 96 h. Observations demonstrated growth inhibition in 50 mg/L from first exposure day for nano and bulk TiO 2 . Furthermore, the chlorophyll a content strongly decreased in nano and bulk in TiO 2 in different days rather than control, respectively. As well as, results showed that, antioxidant values in nano-treated samples were higher than bulk in comparison control. In addition, we found that nano was more toxic than bulk. We aimed, indicating critical impacts of nTiO 2 on the ecosystem.