Olubunmi, F.E., Department of Chemistry, University of Ado-Ekiti, Nigeria; Olorunsola, O.E., Department of Chemistry, University of Ado-Ekiti, Nigeria
Ten heavy metals (Fe, Cu, Mn, Cr, Zn, Hg, Pb, Cd, NI, and V) were analyzed in sediment samples in the dry and wet seasons of year 2008 using AAS. Mercury was not detected in all the samples. The mean concentrations of the heavy metals in sediment (0.38±0.03ppm to 6,619±290ppm - dry season and 0.24±0.05ppm to 8,144±229ppm - wet season) were lower than the values recommended in Consensus-Based Sediment Quality Guidelines of Wisconsin. In the dry season, Enrichment Factors (EF) of the heavy metals in sediment calculated ranged from 0.52 to 2.20. The low values of EF show that the enrichment of sediment by heavy metals was by natural process. The Geo-accumulation Index (Igeo) calculated in both dry and wet seasons gave values indicating no pollution to moderately polluted. From the analysis of variance with Statistical Analysis System (SAS), the mean concentration of metals in sediment in the two seasons (a level=0.05) are not significantly different which implied that the metals were held firmly in the matrix of sediment. © EuroJournals Publishing, Inc. 2010.