Investigation of the genotoxic and cytotoxic effect of nanoplastics on tetrahymena thermophila, an aquatic organism

Plastic waste is very important for environmental pollution. Due to the increasing environmental presence of nanoplastics that emerge with the production and erosion of plastics over time, it is becoming more important to investigate their potential effects on living organisms. In this study, the genotoxic and cytotoxic effects of nanoplastics on an aquatic organism, Tetrahymena thermophila, were investigated. Nanoplastic exposure was performed on Tetrahymena thermophila at different concentrations. Cell viability was evaluated with the MTT test, and it was determined that it showed a cytotoxic effect depending on the concentration. Moreover, the LD₅₀ value was determined as 183,71 mg/L. DNA damage was analysed with the COMET (alkaline single cell gel electrophoresis) test and it was determined that nanoplastics caused genotoxic effects. Catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST) enzyme activities were measured from oxidative stress parameters, and it was observed that nanoplastics disrupted the antioxidant defence system and caused oxidative stress. Lipid peroxidation (MDA levels) analyses confirmed the presence of oxidative damage in cell membranes. These findings reveal the potential risks of nanoplastic pollution on aquatic ecosystems and constitute an important reference for further studies.