Determination of the Concentration of Heavy Metals in Organs and Bone of Selected Fish Species from Ega River in Idah Kogi State, Nigeria

Four different fish species (catfish, Titus, tilapia and sharwa) were obtained from Ega River in Idah, Kogi State, Nigeria, and was investigated for the presence of ten selected heavy metals (Zn, Cu, Cr, Mn, Ti, Ni, Fe, V, Co and Pb). The fish species were carefully dissected and the organs (gills and liver) and bone were prepared, digested using a modified procedure for the Association of Official Analytical Chemists, and were subsequently analysed using atomic absorption spectrophotometry. The study revealed that the highest concentration range of Ti (3.89 – 11.23 mg/kg) was recorded in the gills, liver and bone of the samples. Concentration levels of V (9.60 mg/kg), Ni (0.75 mg/kg), Pb (0.68 mg/kg), Fe (0.60 mg/kg) and Co (0.22 mg/kg) were mostly detected in the gills. Concentrations of all heavy metals detected except Ti, Zn, Ni and V in the fish species were higher than the WHO/FAO permissible limits. Thus, the fishes in Ega River contain objectionable amounts of Cu, Cr, Mn, Fe, Co and Pb, and by the effect of bioaccumulation are unfit for human consumption.