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Bioaccumulation of heavy metals in Oreochromis niloticus (Linn.1758) of Agodi Reservoir, Ibadan, Nigeria

MOJ Ecology & Environmental Sciences
Ogungbile PO,1 JA Akande,1 AO Adepoju,2 TO Ogunbode,1 MKC Sridhar3

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The concentration of Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn in Oreochromis niloticus (generally called Tilapia fish) was assessed at three different locations along Agodi Reservoir in Ibadan. Their relative concentrations were determined using Atomic Absorption Spectrophotometer (AAS). Test location differences and seasonal variations of the values were examined using statistical analysis of variance at P<0.05 to establish pollution dynamics. The results showed declining order of heavy metal concentrations in the order of Mn>Fe>Zn>Cu>Co>Cd>Pb>Ni. Gradient effect was indicated. While Cd was found in decreasing order of concentration from inlet to the outlet, other metals like Co, Cu, Fe, Mn, Ni, Pb, and Zn had concentrations that gradually increased from inlet to the outlet. The concentration of Cd, Co, Cu, Pb, and Zn did not change considerably with season unlike Fe, Mn, and Ni that exhibited substantial seasonal variation. It was concluded that heavy metal accumulation caused marked pollution dynamics inside the Agodi Reservoir. Also, bio-accumulation of the metals in Oreochromis niloticus could give birth to location and seasonal dependency.


Agodi Reservoir, Oreochromis niloticus, Heavy metal, Bioaccumulation, Gradient effect