Fractionation Status and Uptake Potentials of Trace Metals in Water Bodies within Niger Delta Region, Nigeria

Abstract

Surface sediments were collected from Itu, Qua Iboe, Imo, Atabong and Iko Rivers within Niger Delta, Nigeria and assessed for their trace metals contents. Sediments were also obtained from Ekpene Ukpa River where there is no major anthropogenic source of contaminants as Control. These sediments were treated analytical and analyzed using atomic absorption spectroscopy for total trace metals and their species. Results indicated that, total cadmium, manganese and iron were above their acceptable limits while total copper, nickel, lead and zinc were lower than their recommended limits. However, total concentrations of all the trace metals in sediments studied were higher than that in Control indicating anthropogenic inputs of these metals in studied rivers. Speciation studies revealed that Cd existed mostly in acid extractable fraction, Mn, Cu, Ni and Fe in residual fraction while Pb and Zn existed mostly in reducible fraction. Cd showed highest risk potential while Fe was the least risky element. Strong positive correlation existed among the trace metals in studied sediments. Qua Iboe River was the most polluted river whereas, Itu was the least contaminated river studied. It was revealed that apart from Fe, other trace metals were mostly from anthropogenic sources. Periodic assessment of these studied water bodies is recommended since the mobilisable proportions of all the metals were higher than immobilisable fractions.