Histopathological impact of industrial wastewater on the vital organs of Oreochromis mossambicus

The acute toxicity of paper mill wastewater to Oreochromis mossambicus was investigated with the lethal concentration (LC50) value 6.5% for 96?h exposure. This concentration was used as a baseline to study the effects of paper mill effluent on histopathological changes in gills, liver, kidney, and brain of fish. In the gills, filament cell proliferation, cellular infiltration, hemorrhage, and epithelial lifting were observed. In the liver, vacuolation of hepatocytes and necrosis were noted. In kidney, exfoliation and swollen with pyknotic nuclei were identified. Similarly, the brain also showed enlarged pyramidal cells, binucleated nuclei, vacoulation, and necrosis. These changes occurred predominantly in 21days following exposure of fish to the industrial waste water. Paper mill wastewater was found to be highly toxic to fish.