Multi-endpoint evaluation of PFOA toxicity in Danio rerio: Oxidative, genotoxic, and metabolomic responses

Per- and polyfluoroalkyl substances (PFAS), such as perfluorooctanoic acid (PFOA), pose increasing environmental concern due to their persistence, bioaccumulation, and toxicity. However, integrated assessments linking biochemical, genotoxic, and metabolomic responses in aquatic organisms remain scarce. This study evaluated the effects of PFOA (0.01-1000 µg L⁻¹; 21 days) in adult zebrafish through biomarkers of antioxidant defense, oxidative and DNA damage, and metabolite profiles. Significant inhibition of catalase (15-67 %) and glutathione S-transferase (39-77 %) was observed, accompanied by marked lipid peroxidation (> 131 % above control). DNA damage reached up to 600 % above control values, detectable even at 0.1 µg L⁻¹. The Integrated Biomarker Response (IBRv2) indicated stronger liver impairment, while principal component analysis highlighted oxidative stress as the main toxicity pathway. Metabolomics revealed alterations in lipid, carbohydrate, and amino acid metabolism, with pronounced disruptions in unsaturated fatty acid biosynthesis and galactose/glycogen pathways at 100-1000 µg L⁻¹, suggesting an energy imbalance. By combining classical biomarkers and metabolomics, our findings provide novel evidence of PFOA's multi-level toxicity and emphasize that sublethal exposure can compromise fish health at environmentally relevant concentrations. These results underscore the ecological risks of PFAS contamination and support the need for stricter environmental monitoring and regulatory measures.