SEASONAL VARIATIONS OF HEAVY METAL CONCENTRATIONS IN WATER AND FISH (Malapterurus electricus) FROM THE OBII STREAM, UFUMA, ANAMBRA STATE, NIGERIA

Abstract

The seasonal variations of heavy metal concentrations in water and fish organs from the Obii stream, Ufuma in
Orumba North, Anambra State, Nigeria, were determined. The heavy metals investigated were Cd, Pb, Ni, Cu,
Zn and Fe and the fish organs used were kidney, muscle and liver. Samples were digested using standard
methods and analyzed using Varian AA 240 Atomic Absorption Spectrophotometer (AAS). The mean
concentrations and standard deviations of the heavy metals were determined using SPSS. Values obtained were
compared with WHO and NESREA standards. Results obtained showed the water to be polluted with Pb, Ni and
Cu in both seasons. The concentrations of heavy metals obtained in the fish organs indicated a certain degree of
bioaccumulation. The order of bioaccumulation showed Cu>Pb>Zn>Ni>Cd>Fe in Kidney;
Zn>Ni>Pb>Cd>Cu>Fe in muscle and Zn>Pb>Cd>Ni>Fe>Cu in liver. The heavy metals bio-accumulated in
the fish organs in the order kidney>liver> muscle. The fish organs were polluted with Cd, Cu, and Zn. Based on
the above findings, a close monitoring of metal pollution of, the Obii stream is strongly advocated, in view of
possible health implications to consumers of the fish from the stream.