Removal of polystyrene nanoplastics from aqueous solution using nano‑Fe3O4 flocculation technology, and evaluation of their reproductive toxicity in mice

Nanoplastics (NPs) are emerging environmental pollutants detected in drinking water and human tissues, yet effective removal methods remain limited. This study developed a magnetic flocculation method using nano‑Fe 3 O 4 combined with KCl to remove polystyrene nanoplastics (PS-NPs) from water, and assessed the biosafety of the treated water in male mice. Under optimized conditions (100 mg/mL Fe 3 O 4 , 1 mg/mL PS-NPs, 25 mM KCl), approximately 96% of PS-NPs were removed via magnetic adsorption, as confirmed by fluorescence quantification and transmission electron microscopy. Mice were administered the treated supernatant as drinking water for 42 days. No testicular toxicity, oxidative stress, inflammatory response, or apoptosis was observed in the treated mice, and ERK/JNK/p38 MAPK and Nrf2/HO-1 pathway protein levels remained unchanged. In contrast, mice exposed to untreated PS-NPs exhibited significant testicular damage associated with pathway activation. These findings demonstrate that nano‑Fe 3 O 4 flocculation is an effective method for removing PS-NPs from aqueous solution, and that the treated water is safe for consumption. This approach offers a potential strategy for reducing nanoplastic exposure.