Comparative Study of Heavy Metal Pollution of Sediments in Odo-Owa and Yemoji Streams, Ijebu-Ode Local Government Area, Sw Nigeria

This study aims at determining the elemental concentrations of Cu, Zn, Cr, Pb, Ni, Co and Cd in the sediment samples from Odo-Owa and Yemoji streams in Ijebu-Ode Local Government Area (L.G.A), South Western (SW) Nigeria, using Atomic Absorption Spectrophotometer and comparing the concentration of these metals in the two streams with other studies and with acceptable concentration values for metals in water. There was no detectable Cd in any of the samples; however all the samples contained a detectable amount of one or more of the other metals of interest. The trend of heavy metals in sediments of Odo-Owa stream is Zn>Pb>Cu>Cr (151.3 mg/kg, 17.74 mg/kg, 6.16 mg/kg, 2.30 mg/kg) while Yemoji is Zn>Cr>Pb>Cu (3.63 mg/kg, 2.37 mg/kg, 1.67 mg/kg, 1.43 mg/kg). Statistical analysis of t-test showed a great significant difference (p<0.05) among metals in Odo-Owa and Yemoji downstream except for Cr. Except for Zn metal (151.3 mg/kg) in Odo-Owa (downstream), the mean concentrations of the metals were below the values obtained from other studies and were within the set by National Oceanic and Atmospheric Administration (NOAA) limits (SQGs for Zn-150 mg/kg, Cu-34 mg/kg, Cr-81 mg/kg, Pb-46.7 mg/kg), so not considered to be a cause for toxicology concern.