Heavy Metals Concentrations in Gills and Liver of Clarias anguillaris and Oreochromis niloticus from an Inland Water

Abstract

Human activities had been the major cause of water pollution globally, and tissues of marine organism could be used as an indicator of the presence and quantity of metals in the water body. The concentrations of some heavy metals (Mn, Cu, Zn, Fe, and Pb) both in the gills and liver of Clarias anguillaris of mean weight 74.44±11.07 g and Oreochromis niloticus of mean weight 97.03±6.09 g were investigated. Samples were analyzed for heavy metals using Atomic Absorption Spectrophotometer (AAS). For Clarias anguillaris the gill was observed to have the highest concentration of Iron (13.83±0.56 mg/kg), while Copper (0.43±0.11 mg/kg) was observed to be the least heavy metal present in the gill. In Oreochromis niloticus the liver was observed to have the highest concentration of Iron (15.27±0.46 mg/kg) while Copper was observed to be the least concentration of heavy metal present. All the heavy metals analyzed were considerably higher than the recommended limit for heavy metals, except for Zn as observed in the gills of both fish. There was variation (P ≤ 0.05) in the concentration of heavy metals in both tissues. This study shows the need for proper monitoring of human activities along this river banks.

Key Words: Heavy metals, concentration, gills, liver and pollution