Heavy metal concentration in selected fish species from Eleyele reservoir Ibadan Oyo State South-western Nigeria

Heavy metal concentrations (lead, cadmium, zinc, copper, chromium and manganese) in selected fish species from Eleyele reservoir Ibadan Oyo State South-Western Nigeria were investigated. A sample each of catfish (Clarias gariepinus), Africa pike (Hepsetus odoe) and tilapia fish (Oreochromis niloticus) from Eleyele lake Ibadan Oyo state were collected from fish farmers at the landing site early in the morning using standard procedure and transported to the laboratory within 30 minutes for laboratory analysis. Heavy metal concentration in the flesh of the fish species and water sample were analysed using atomic absorption spectrophotometer. There existed significant difference (p<0.05) in the concentration of heavy  metals in fish flesh of various fish species with that of herbivorous fish (Tilapia fish) being the highest followed by omnivorous fish (catfish), followed by piscivorous fish (H. odoe), while that of the water body was the lowest. It was concluded that fish could be considered bio-indicator of environmental contamination within the aquatic ecosystem; it also indicates that fish could be useful in estimating bioavailability of metal to freshwater biota.   Key words: Heavy and trace metal, Clarias gariepinus, Hepsetus odoe, Oreochromis niloticus, Eleyele reservoir.