Distribution and Risk of Metals in Soils of Refuse Dumpsites in Some Urban Towns in Delta State, Nigeria

Abstract

Refuse dumpsites often contain materials capable of polluting surrounding soils. In this study, the spatial
distribution of metals in soils of refuse du mpsites in three urban towns (Ughelli, Sapele, Orhuwhorun) in Delta State, Nigeria
were examined. Soil samples were collected from three dumpsites in the aforementioned towns at depths 0 15 cm, 15 30 cm
and 30 45 cm, respectively. Some physicochemical pro perties of the soil profiles such as pH, Electrical Conductivity (EC)
and Total Organic Carbon (TOC) were determined using standard methods, while metals concentration were determined
using atomic absorption spectrometry after digestion with aqua regia Th e results for all sites and depths ranged as follows:
pH: 4.64 to 7.85; EC (μ ʃ cm 1 ): 60.8 to 451; and TOC (%): 0.06 to 1.49 %. Metals concentration (mg kg 1 ) ranged as
follows: 0.05 to 4.5 for Cd, 9.0 to 149 for Pb, 4.20 to 15.4 for Cr, 1.0 to 14 .5 for Ni, 1.0 to 124 for Cu, 20 to 510 for Zn,
and 1650 to 11865 for Fe. The potential ecological risk of the metals is in the order of Cd > Pb > Cu > Zn > Cr > Ni. The
study indicates that the metals studied except Cd do not pose environmental risk c ons idering their relatively low
concentrations.