Complex Interactions and Ecotoxicological Consequences of Tannery Effluents on Aquatic Life: Differential Responses in Scinax Fuscovarius Tadpoles and Poecilia Reticulata Fish

Tannery industries contribute significantly to economic growth but generate highly toxic effluents, posing severe threats to aquatic ecosystems. This study assessed the ecotoxicological impacts of tannery effluents on Scinax fuscovarius tadpoles and Poecilia reticulata fish. Tadpoles and fish were exposed to environmentally relevant dilutions (0.3%) of raw tannery effluent (RTE) and effluent treated with mercerized microcrystalline cellulose particles (TTE) for 15 days. RTE exposure caused a 74.9% reduction in catalase (CAT) activity and a 50% increase in micronucleated erythrocytes in tadpoles, alongside heightened oxidative stress and inflammation. In fish, RTE exposure led to a 30% increase in superoxide dismutase (SOD) activity and moderate cytogenotoxic effects, reflecting their lower chromium (Cr) accumulation (0.5 mg/g in fish vs. 1.2 mg/g in tadpoles). TTE treatment significantly reduced Cr concentrations by 60% in tadpoles and 50% in fish, mitigating toxicity. However, residual sublethal effects persisted, including oxidative stress markers and nuclear abnormalities in both species. These findings highlight the differential sensitivity of aquatic species to tannery effluents and the partial efficacy of TTE in reducing toxicity. The results provide critical data for advancing remediation strategies, emphasizing the need for technologies capable of addressing residual toxicity. Furthermore, this study underscores the importance of multi-species ecotoxicological assessments and biomarker-based approaches in regulatory frameworks to ensure the ecological safety of treated industrial effluents. Future studies should explore long-term and transgenerational impacts to build a comprehensive understanding of these pollutants' ecological and evolutionary consequences.