Heavy Metal Concentrations in Three Commercially Important Fish Species in the Lower Sombreiro River, Niger Delta, Nigeria

Concentrations of heavy metals (Fe, Cd, Cu, Co, Cr, Pb, Ni and Zn) in the tissues of three commercial fish species (Pseudotolithuselongatus, Chrisichthysnigrodigitatus and Mugilcephalus) of Sombreiro River were investigated. Heavy metal concentration in the tissues of these fishes were found to be different, however M. cephalus was observed to accumulate a higher burden of Fe, Cr, Ni, Co and Zn while Cd was not detected in all three species. The order of mean concentration of metals in the tissues of P. elongatus and C. nigrodigitatus were similar (Fe > Zn > Cr > Cu > Ni > Co >Pb> Cd) while that of M. cephalus is Fe > Zn > Cr > Ni > Cu > Co >Pb> Cd. It is concluded that M. cephalus is a better accumulator of heavy metals and is therefore most suitable for use as a biological indicator in the Sombreiro River. Key words: Sombreiro River, Accumulation, Heavy metal, Tissue, Niger Delt