Different Toxic Effects of Polystyrene Microplastics and Nanoplastics on <scp> <i>Caenorhabditis elegans</i> </scp>

Exposure to polystyrene microplastics/nanoplastics (PS-MPs/NPs) may induce severe toxic effects in organisms. This study compared the toxicity of 2-μm PS-MPs and 0.1-μm PS-NPs by using Caenorhabditis elegans (C. elegans) as the experimental model. The ingestion of both particles increased with increasing exposure concentration. PS-MPs were taken up more at 0.1, 1, and 10 mg/L, while PS-NPs were ingested more at 100 mg/L. At concentrations ≥ 1 mg/L, both PS-MPs and PS-NPs negatively affected the growth, locomotion, lifespan, and reproduction of C. elegans and induced oxidative stress. At concentrations of 10-100 mg/L, PS-MPs caused greater toxicity in terms of locomotion, reproduction, and reactive oxygen species (ROS) induction. Notably, the PS-MPs/NPs ingested by the parental generation were not transmitted to offspring. This study showed the distinct toxicological impacts of PS-MPs and PS-NPs on C. elegans, hence enhancing comprehension of the risks to the environment posed by MPs/NPs.