Authors : A.G.M. Osman, K.Y. Abuel-Fadl, A.M. Elbtar and M.A.M. Taha
Abstract: The contamination of water, sediments and biota with heavy metals is of important concern because of their toxicity, persistence and bio-accumulative nature. The present researchers was aimed to study the effects of seasons on the concentrations of Pb, Cd, Cu, Cr and Fe in water, sediment and freshwater fish (Clarias gariepinus) collected from the whole course of the River Nile form its spring at Aswan to its estuaries at Damietta and Rosetta. Water, sediment and fish samples collected from Damietta and Rosetta sites displayed highest metal concentrations. This was expected due to the fact that the level of contamination is greater downstream River Nile, compared to upstream sampling sites. The highest seasonal mean levels of the selected heavy metals in water and sediment samples were recorded during spring period along the whole course of the River Nile. The lowest ones were recorded during autumn for nearly all heavy metals. The levels of heavy metals in the tissues of the selected fish showed highly significant differences between seasons. According to the result of the present research, seasonal variations of heavy-metal levels in the tissues of African catfish follow sinusoidal curves. The maximum level of most heavy metals was detected during summer which represents the growth period of the African catfish. The minimum level of most metals was recorded during autumn period which corresponds the breeding season of Clarias gariepinus. This confirmed the accumulation of some metals in the gonad tissue which intern eliminated from the tissue during spawning seasons.
A.G.M. Osman, K.Y. Abuel-Fadl, A.M. Elbtar and M.A.M. Taha, 2012. Seasonal Variations of Some Heavy Metals in Water, Sediments and Fish Samples Collected from the River Nile, Egypt. Environmental Research Journal, 6: 321-328.