Seasonal and Habitat Variation in Heavy Metal Concentration in Selected Fishponds and their Feeder Streams in Osun State

The presence of heavy metals in the environment could constitute a hazard to public health. Hence, the present study determined heavy metal (Pb, Co, Cr, Cu, Cd, Ni, Fe, Mn, Zn) concentrations in three selected earthen fish ponds and their feeder streams in Osun State, South-West, Nigeria, during the rainy and dry seasons of 2011 and 2012. The analysis was carried out using an atomic absorption spectrophotometer (AAS). The results revealed that most heavy metals were higher in the dry season than in the rainy season. In addition, high levels of the metals were generally recorded in the feeder streams rather than in the ponds, which confirms the stream as a potential source of heavy metal pollution to the fish ponds. A significantly (p=0.05) higher concentration of Zn was observed in Ilesha pond compared to the stream water. On the other hand, Ni concentration in Osogbo and Yakoyo streams was significantly higher than in the pond water.