Effect of polystyrene nanoplastics on its toxicity and reproduction in Philodina roseola

Micro-nano plastics have emerged as a major ecological concern. The nanoplastics (NPs) pose a huge threat to microscopic animals. Our study aims to decipher the effect of polystyrene nanoplastics (PSNPs) of 50 and 100 nm sizes on a bdelloid rotifer (Philodina roseola). Both sizes of PSNPs were analyzed using field emission Scanning electron microscopy, Fourier transform Infrared spectroscopy, and Dynamic light scattering analyses. The LC₅₀ values for 50 and 100 nm PSNPs at 48 h upon interaction with the rotifers were 16.36 and 22.94 mg/L respectively. The total protein and superoxide dismutase levels decreased with an increase in concentration in both PSNPs upon interaction at various concentrations (4, 8, 12, and 16 mg/L). Whereas the lipid peroxidase and reactive oxygen species levels increased with an increase in concentration for both PSNPs at similar concentrations. Further, both PSNPs were found to cause internal organ damage in rotifers. A delay in the hatching rate was observed when the rotifers interacted with both PSNPs in addition to the decrease in the hatching rate of F₁ generation. Therefore, PSNPs pose a threat to the natural life cycle in the rotifers.