Heavy Metal Contamination in Selected Dumpsites of Osubi, Warri, Western Niger Delta, Nigeria

Abstract

This study investigated on the concentrations of five (5) heavy metals such as Cadmium, Lead, Copper, Manganese and Zinc on soil in dumpsites of Osubi vicinity in Delta state, Nigeria using acid digestion and Atomic Absorption spectrophotometer. The range of metal concentrations in the Osubi Municipal dumpsite were: Cu(4.7 – 9.25 Mg/Kg) , Pb(1.4 – 3.7 Mg/Kg) , Mn(12.9 -29.5 Mg/Kg) , Cd(<0.1 Mg/Kg) , Zn(3.05 – 11.4 Mg/Kg) whereas range of metal concentrations in Osubi Abattoir Dumpsite were Cu(9.35 – 23.45 Mg/Kg) , Pb(1.1 – 24.55 Mg/Kg) , Mn(44.1 - 71.6Mg/Kg) , Cd(<0.1 – 0.4 Mg/Kg) , Zn(49.7 – 201.8 Mg/Kg) and the ranges for the control samples were : Cu (2.85 – 3.6 Mg/Kg) , Pb (0.35 – 1.3 Mg/Kg) , Mn (22.15 -67.1 Mg/Kg) , Cd (<0.1 Mg/Kg) , Zn (5.95 – 17.85 Mg/Kg). The concentrations of heavy metals fell below the WHO/FAO standards for soil and all but Zn in Osubi Abattoir dumpsite fell within the permissible limit of the Dutch standard. The Geo Accumulation index showed no contamination in all samples except Pb and Zn in samples 5, 8 and 9 which shows moderate contamination. The contamination factor showed that all are uncontaminated except Pb and Zn in samples 5, 8 and 9 which are moderately contaminated and considerable contamination for Cd in sample 9. The Ecological Risk Factor showed that all heavy metals show low risk except Cd which shows considerable risk for its only sample seen and Lead which shows low moderate risk. In PLI (Pollution Load Index), all samples show no sign of pollution, although its value of 0.91 in sample 9 was close to the baseline of 1. In the comparison of dump sites, Osubi Abattoir was indicated to possess more heavy metal concentration than Osubi municipal dumpsite. The strong association between Pb/Cu, Mn/Cu, and Zn /Mn. Influenced by anthropogenic activities suggest a similar source .