Oxidative stress and histopathology responses of Clarias gariepinus exposed to simulated waste ash leachate from Onitsha dumpsite, Nigeria

Abstract Background Open burning of waste, which is a prevalent waste management approach, pollutes the environment and harms wildlife and human health. This study investigates the biological toxicity potential of simulated waste ash leachate (SAL) through oxidative stress biomarker and histology assessment in Clarias gariepinus . Methods The physicochemical properties of SAL were evaluated using conventional methods. Fish were exposed to SAL at sublethal concentrations (0, 4.74, 7.11, 14.22, and 28.45%) for 21 days. The fish's gills and liver were examined for oxidative stress indicators and histopathological features. Results The analysed trace metals were found to be above their acceptable limits. Fish exposed to SAL showed substantial increases ( p < 0.05) in superoxide dismutase, catalase, malondialdehyde, and glutathione peroxidase levels, as well as a decrease in total protein levels, compared to the control group. Furthermore, the histological studies revealed that SAL induced concentration- and duration-dependent alterations in the gill and liver of C. gariepinus . Histological alterations in the fish liver included cytoplasmic vacuolation, cellular infiltration, hepatic lipidosis, necrosis, and nuclear pyknosis, whereas epithelial lifting, lamella oedema, lamellae fusion, and epithelial hyperplasia were observed in the gills. Conclusion Findings from this study suggest that SAL contains toxic elements and compounds capable of posing severe health risks to wildlife and humans. Sanitary waste management techniques, including recycling programmes, are critical to avoiding the negative consequences of prolonged indiscriminate solid waste burning, which can directly harm the environment and public health.