Cadmium and lead levels in fish (Tilapia nilotica) tissues as biological indicator for lake water pollution.

Cadmium and lead were determined in different tissues (muscle, gill, stomach, intestine. liver, vertebral column and scales) of Tilapia nilotica from the High Dam Lake, Aswan (Egypt) to assess the lake water pollution with those toxic metals. Fish samples were chosen from different ages and weights to be analyzed along with samples of the aquatic plant (Najas armeta), sediment and lake water. The results showed that cadmium and lead concentrations were higher in fish scales and vertebral column than in the other parts of the fish. Cadmium and lead levels in High Dam lake water and fish (Tilapia nilotica) were a result of the pollution which uptakes from aquatic plants, sediments and gasoline containing lead that leaks from fishery boats. Tilapia nilotica fish was used as a good bio-assay indicator for the lake pollution with cadmium and lead. The fish muscles in this study were in the safety baseline levels for man consumption.