Assessment of Toxicity Induced by Different Domestic and Industrial Wastes in Nile Tilapia (Oreochromis niloticus)

Abstract

The River Nile represents the principle freshwater resource. It represents the major source for the potable water which is susceptible to be polluted by different metals. Heavy metals are the most common pollutants in aquatic environment. The present study aimed to evaluate the adverse effect of heavy metals on in liver and kidney tissues of Nile Tilapia (Oreochromis niloticus) that were collected from El-Kanater El-Khayria and two discharge points (El-Rahawy drain and Kafr El-Zayat industrial area) at Rosetta branch, River Nile, Egypt. During the present study, it was found that concentration of Lead (Pb), Cadmium (Cd), Iron (Fe) and Zinc (Zn) elevated significantly (P<0.05) in livers of fishes living in Rahawy and Kafr El-Zayat with respect to liver of fishes living in water of kanater. No differences observed significantly in concentration of Nickle (Ni), Chromium (Cr), Cobalt (Co) and Copper (Cu). On the other hand, it was noticed that concentration of Pb, Cd, Ni, Fe and Zn increased significantly (P<0.05) in kidney of fishes living in Rahawy and Kafr El-Zayat with respect to kidney of fishes living in water of kanater. There were no significant differences in concentration of Co and Cu. Bioaccumulation of the various heavy metals in liver and kidney tissues of fishes caused different mutagenicity in the native protein and isoenzymes detected electrophoretically. These alterations were represented qualitatively by hiding of the normal bands or appearance of abnormal bands with different relative mobilities and quantities. Moreover, these abnormalities might occur quantitatively by changing quantities of the qualitatively normal bands. The study concluded that presence of the heavy metals with higher concentration could be toxic and affect fishers and other aquatic organisms and this is worrisome in view of the health implications for the population that need fish resources to cover the food requirements.