Determination of some heavy metals concentration in the tissues of Tilapia and Catfishes

Lead (Pb), Cobalt (Co), and Copper (Cu) concentrations were determined in bone, muscle and gill of two fish species (tilapia fish and cat-fish) collected from Tiga dam Kano, Nigeria during October, 2010. The mean concentrations of the heavy metals varied depending on the type of the tissue and fish species. Generally cat-fish showed the highest level of Pb (7.60 ± 2.33 mg/L) and Cu (0.506 ± 0.4 mg/L) metals in the bone and muscle tissues respectively. Cobalt (Co) showed the highest concentration in tilapia fish. In tilapia fish, the concentration of copper in the gills was not detected. In cat-fish, the bone recorded the lowest level of cobalt (5.20 ± 1.24mg/L) while the gills recorded the lowest level. The concentration of copper (0.506 ± 0.40mg/L) was maximum in the muscle and lowest in the bone of cat fish. In cat fish, Pb showed higher level (7.60± 2.033mg/L) in the bone and least in the gills. In tilapia fish, cobalt recorded higher concentration in gills and least in bones. And also Pb has higher concentration in the gills (2.30 ± 0.44mg/L) and lowest ( 0.90 ± 0.42mg/L) in bone of tilapia fish.