Polyester microfiber accumulation and toxicological effects on freshwater fish Labeo rohita.

Synthetic polyester microfibers (PES-MFs) are emerging contaminants that pose a serious risk to aquatic organisms. This study evaluated the toxicological effects of PES-MFs on the freshwater Juvenile fish Labeo rohita, which were exposed for 21 days to environmentally relevant concentrations. Toxicity was assessed through ingestion rates, behavioural response, and biochemical biomarkers, including oxidative stress enzymes (SOD, CAT, LPO, GPx, GSH), and brain Acetylcholinesterase (AchE). Results revealed significant physiological stress, with elevated LPO and enzymatic imbalances in the gills and gastrointestinal tract (p < 0.05). Behavioural changes such as reduced feeding, increased aggression, and decreased growth were observed. Microfiber ingestion was dose-dependent. Biochemical analysis showed a significant increase (p < 0.001) in protein, carbohydrate, and lipid levels in the tissues of exposed fish. These findings confirm that exposure to PES-MFs causes physiological stress, disrupts metabolic balance, and harms the health and behaviour of L. rohita, highlighting the need to control microfiber pollution in freshwater ecosystems.‎.