Heavy Metals Level in <i>Clarias gariepinus</i> (Catfish), <i>Oreochromis niloticus</i> (Tilapia) and <i>Chrysichthys nigroditatus</i> (Bagrid catfish) collected from Ogun River, Ogun State, Nigeria

Abstract

Aquatic organisms such as fish are prone to contamination by water pollutants such as heavy metals. This study aims at assessing the levels of heavy metals in the fillet tissues of 75 fish samples comprising Clarias gariepinus (Catfish), Oreochromis niloticus (Tilapia) and Chrysichthys  nigroditatus (Bagrid catfish) from five (5) different fishing locations along the Ogun River, Ogun State. The fillet tissues of the fish samples were digested and analysed for Zn, Pb, Fe, Cr and Cd using a Perkin Elmer, AAnalyst – 200 Atomic Absorption Spectrometer. The concentration of Zn in Clarias gariepinus, Oreochromis niloticus and Chrysichthys nigroditatus were 5.37±2.558, 6.58±2.35 and 5.11±1.55 respectively; while the levels of Pb in the species were Clarias gariepinus (1.30±3.099), Oreochromis niloticus (1.01±0.95) and Chrysichthys nigroditatus (0.35±0.59). Concentrations of Fe, Cr and Cd in the species were Clarias gariepinus (8.87±3.547, 0.08±0.098 and 0.09±0.100), Oreochromis niloticus (8.96±2.21, 0.12±0.11 and 0.11±0.11) and Chrysichthys nigroditatus (8.16±3.88, 0.11±0.11 and 0.11±0.11). The data revealed that most of these values were lower than  FAO/WHO permissible except Pb and Cr. Some of the fish sampled may pose health hazards to the consumers. There is a need for constant monitoring of pollutants in Ogun River.

Keywords: Heavy metals, Clarias gariepinus, Oreochromis niloticus, Chrysichthys nigroditatus, Ogun River