ABSTRACT
A study on the quality of soil samples was carried out to analyze the physico-chemical and trace metals (Mn, As, Zn, Cd, Cr, Pb, Ni, and Hg) status from two dumpsites in Agaga Community, Ugborikoko and Environs Warri, Delta State. Forty soil samples were collected at depths of 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm representing topsoil and subsoil soils respectively and also from control (pristine environment). These soil samples were digested into solution using aqua regia and analyzed using the Atomic Absorption Spectrometer (AAS), [Buck model 210 VGP]. The result of the analysis was then subjected to statistical treatment (One-way Analysis of Variance) to ascertain significant difference among the trace metals and status of contamination pollution respectively. Result from the analysis showed the pH ranged from 3.30-6.10, indicating acidic soils. The extent of contamination level based on the average metal contents obtained from soil samples at the different depths is as follows: Mn; 13.1-20.5 mg/kg, Arsenic; 4.4-12.3 mg/kg, Zn; 6.0-18.4 mg/kg, Cd; 0.2-3.51 mg/kg, Cr; 0.05-1.61 mg/kg, Pb; 10.7-19.5 mg/kg, Ni; 2.6-16.4 mg/kg, and Hg; 0-0.008 mg/kg compared with the control soil. At all locations investigated, the heavy metals (Mn, As, Zn, Cd, Cr, Pb, Ni, and Hg) obtained were much higher than that from the control sample at various depths. ANOVA results at P<0.05, indicated significant differences in concentrations among Mg, Ca, Cl, SO4, Mn, As, Cd, Cr and Ni at topsoil and subsoil depths between the dumpsites and control in the study area which were higher than their respective control values. This confirmed that the soils in the studied locations at several depths are facing probable environmental pollution with dangerous heavy metals such as As, Mn, Cr, Cd, and Ni. By extrapolating from the soil samples and control, it is concluded that the intrinsic topsoil and subsoil quality at both dumpsites are polluted and deteriorating especially with these five trace metals; Mn, As, Cd, Cr and Ni which is a reflection of anthropogenic contribution from the indiscriminate dumping of solid wastes from the dumpsites in the study area.
