Heavy metal concentrations in Bottom Sediments of Ikpoba River, Edo State, Nigeria

The concentrations of Fe, Mn, Zn, Cu, Pb, Cr, Ni and V were investigated. Samples were collected fortnightly from five (5) stations for four months (July to September, 2009) using Ekman grab operated by hand in shallow water. Station 1 is upstream (Old capitol bridge) and stations 2, 3, 4 and 5 are downstream. The main concentrations (ppm) in stations 1, 2, 3, 4 and 5 are: 931, 117, 812, 679 and 619.7 (Fe); 12.11, 21.08, 9.58, 8.64 and 7.89 (Mn); 9.90, 12.5, 9.64, 7.07 and 6.62 (Zn); 7.88, 8.04, 5.81, 4.34 and 3.88 (Cu); 0.48, 0.61, 0.36, 0.26, and 0.28 (Pb); 0.19, 0.26, 0.13, 0.12 and 0.11 (Cr); 0.12, 0.16, 0.08, 0.08 and 0.08 (Cd); 0.13, 0.19, 0.13, 0.11 and 0.11 (Ni) and 0.10, 0.15, 0.10, 0.09 and 0.09 (V). Analysis of variance (ANOVA) showed that Fe (Stations 1 and 2), Cr (Stations 1 and 2) and Cd (Station 2) were significantly different (p 0.05) between stations. All parameters studied were below FEPA limits. The heavy metal concentrations in bottom sediments of Ikpoba River showed a seasonal pattern of variation. This investigation in comparison with earlier study based on data from Jimoh, 2006; show that Fe and Mn concentration increased overtime while Cd, Pb, and Cu did not