ASSESSMENT OF HEAVY METALS CONCENTRATION IN SOME ORGANS OF NILE TILAPIA(Oreochromis niloticus)IN WAYA DAM, BAUCHI.

Résumé

The study was conducted in Waya dam, Bauchi state, Nigeria to determine the concentrations of heavy metals in bones, gills and muscle tissues of Oreochromis niloticus. Nine O. niloticus were obtained from fishers fishing in the dam in May, 2018. Fish tissues collected were digested with concentrated HNO3 and H2SO4 according to standard procedures. Heavy metals concentrations (Fe, Cd, Cu, Zn, Pb and Ni) after digestion were analyzed using 210 VGP atomic Absorption Spectrophotometer. The result shows that gills had highest concentrations (1.590±0.767 mg/kg) of Fe and lowest concentrations (0.004±0.001 mg/kg) of Ni. Gills tissues had highest mean heavy metal load than bones and muscle tissues. Mean concentrations of Zn was highest (0.228±0.076 mg/kg) in gills and lowest (0.077±0.076 mg/kg) in bones. Mean concentrations of the heavy metals in O. niloticus tissues studied were of the order: Fe˃Zn˃Cu˃Cd ˃Pb˃Ni. The mean heavy metal concentrations obtained in the study indicated that the fish species was safe for human consumption. It is recommended to periodically monitor the concentrations of heavy metals in Waya dam and in similar water bodies in order to prevent possible related health hazards.