NATHALIE EBELECHUKWU ILODUBA

The discharge of wastewater into waterbodies without proper treatment has led to several threats such as DNA damage to aquatic species. This study evaluates the genotoxic effect of cassava wastewater on the gonads, liver and gills of post juvenile Clarias gariepinus using comet assay. The post juveniles of Clarias gariepinus was purchased from fish farm located in Delta State and was exposed to various concentrations (0.2%, 0.3%, 0.5%, 0.7%) of cassava wastewater for 96 hours. Unlike normal behaviours observed in the control groups, the fish exposed to the effluent were restless, erratic in their movement and gasping for breath. After the exposure period, the fishes were transported to the laboratory and the cells of their liver, gills and gonads were extracted for genotoxic assessment using comet assay. The result obtained from the genotoxic assessment revealed DNA damage at varying concentrations of the wastewater. The study revealed that genotoxins present in the wastewater were obviously responsible for the DNA damage in the tissues in the organism. The study also revealed that the genotoxic effect of cassava wastewater on post juveniles of Clarias gariepinus is dose
dependent as DNA damage increases with increased concentration. This study shows that the treatment of wastewater before disposal is very important.