SPECIATION AND QUANTIFICATION OF LABILE HEAVY METAL DISCHARGES IN OGUN RIVERS USING DGT TECHNIQUE.

Abstract

This study profiled labile exogenous metals ubiquitous in the ecology of Ogun River induced by persistent anthropogenic activities along the riverbanks. The labile metals existing as metal-ions were trapped with a passive sampling technique of diffused gradients in thin films (DGT) subsequent upon which the metal-ions were carefully extracted and analyzed using the Atomic Absorption Spectroscopy (AAS). Nine labile metals (Pb, Cd, Ni, Cr, Co, Cu, Mn, Fe and Zn) were targeted in this study. The results of the study showed that mean values of labile Fe and Zn exceeded 3 µg/L whilst those of labile Pb, Cd and Mn occurred in the range of 1.41 and 1.88 µg/L in the river matrices. The mean values of labile Cr, Co, Ni and Cu occurred below 1.0 µg/L in the river matrices. The high industrial activities and population density along the Isheri, Ilo and Owo axes of the Ogun River accentuated the presence of labile Pb, Zn and Fe in the river matrices.