Assessment of Oxidative Stress, Vitellogenin, and Human Health Risks Derived From Nile Tilapia Exposed to Metals and...

Urban coastal lagoons are highly vulnerable ecosystems increasingly affected by metal contamination, as well as multiple anthropogenic stressors. This study evaluated ecotoxicological and human health risks associated with chronic metal exposure in Nile tilapia (Oreochromis niloticus) from an anthropogenically impacted lagoon in southeastern Brazil. Monitoring was conducted over one year (2022-2023) across four seasonal campaigns. Fifty-seven tilapia specimens were collected during dry and rainy seasons, and liver and muscle tissue were analyzed for antioxidant biomarkers (superoxide dismutase-SOD, glutathione S-transferase-GST, reduced glutathione-GSH, total antioxidant capacity-TAC), oxidative damage (lipid peroxidation-LPO, protein carbonyl-PTC), and metal detoxification (metallothionein-MT). Endocrine disruption was assessed via plasma vitellogenin (VTG), and human health risks were estimated. Metal and metalloid diversity was higher in the dry season (12 vs. 7 elements), with some sites (P1-P3) presenting critical levels. Metals and metalloids in MT-enriched subcellular tissue fractions revealed seasonal shifts in As, Co, Rb, and Se, with Cd, Hg, and Pb detected only in liver during the dry period. Sex differences observed regarding GSI (females > males; p ≤ 0.05) aligned with higher male VTG levels. Antioxidant responses were higher in the dry season (hepatic SOD +81.9%), while oxidative damage increased substantially in both tissues (muscle +75.7%, liver +79.6%). The applied integrated biomarker-metal approach revealed a clear dry-season intensification of metal and metalloid exposure and biological responses, emphasizing endocrine and oxidative alterations and highlighting the need for seasonal biomonitoring efforts.