Dose-dependent proteomic profiling uncovers toxicity transformation of nanoplastics induced by simulated fenton oxidation in urban wastewater treatment

Nanoplastics can escape conventional wastewater treatment and undergo further transformation during advanced oxidation processes in wastewater treatment plants. However, this transformation and toxicity alterations remain poorly recognized and lack systematic investigation. This study simulated the environmental transformation of polystyrene nanoplastics (PS-NPs) via Fenton treatment to mimic wastewater processing and compared the physicochemical properties and toxicological effects of Virgin and Fenton-treated PS-NPs. Fenton-treated PS-NPs showed increased surface roughness, reduced size, and more negative zeta potential, indicating enhanced dispersibility. In vitro, Virgin PS-NPs more strongly reduced neuronal viability, while Fenton-treated PS-NPs induced higher ROS levels. In Caenorhabditis elegans, Fenton-treated PS-NPs significantly impaired locomotion, development, and aging-related phenotypes. Dose-effect relationship analysis at the proteomic level revealed disruptions in ribosome function, carbon metabolism, and reproductive pathways. These findings highlight the complex toxicity mechanisms of transformed microplastics during wastewater treatment and provide insights for ecological risk assessment of microplastics in wastewater treatment processes.