Comparative evaluation of the adverse effects wastewater effluents on Channa punctata through oxidative stress and histopathological alterations

This study investigates the adverse effects of wastewater effluents on Channa punctata, collected from upstream (Methwasa), point-source (Juna Nagda), and downstream (Parmarkheri) locations along the Chambal River at Nagda, Ujjain, India. The research focuses on oxidative stress responses and histopathological alterations in fish gills, liver, and kidneys. Catalase and glutathione S-transferase activities were significantly higher at Juna Nagda and Parmarkheri compared to the upstream site (Methwasa) (p < 0.05), suggesting the activation of antioxidant defense mechanisms due to pollution exposure. Histological analysis revealed the most severe tissue damage in fish from Juna Nagda, followed by Parmarkheri and Methwasa. The Integrated Biomarker Response (IBR) for oxidative stress and histopathological changes consistently indicated higher values at the polluted sites. Water temperature, electrical conductivity (EC), and nitrate levels were identified as potential factors influencing these biomarker responses. The study concludes that thermal effluents discharged into Juna Nagda are responsible for the observed effects. Overall, integrated biomarkers, particularly histopathological alterations, offer a reliable tool for monitoring the prolonged impacts of wastewater effluents on aquatic organisms.