Chemical Speciation and Mobility Factors of Heavy Metals in Soil Around an Integrated Steel Complex Communities

Abstract

Some heavy metals, consisting of Fe, Cd, Co, Cu, Mn, Ni, Pb and Zn were determined using USEPA Method 3050B for total metal concentration. Six composite samples were located from Aladja (ALJ), Ovwian (OVW), Ejevwu (EJW), Ekete Inland (EKI}, Orhuwhorun (ORH), and Otor-Udu (OTU) towns. In addition, chemical speciation was carried out on these samples using method employed by Tessier et al. as modified by Kersten and Forstner to assess their speciation pattern and the fraction of abundance as determinant of environmental pollution. From the results obtained, concentrations of Fe, Cd and Mn were more predominant in the residual fraction (F5) in the form of Fe3+, Cd2+ Mn2+ respectively for both wet and dry seasons. Co was more in the exchangeable fraction (F1) as Co2+ for both seasons. Concentration of Cu in the form of Cu2+ is higher in Fe-Mn oxide fraction (F3) for wet season and dry season’s organic fraction (F4). Pb and Zn were abundant in Fe-Mn oxide fraction (F3) for both seasons as divalent ions. Mobility factor calculated for the metals shows pattern in the order: Pb > Co > Zn > Mn > Fe > Cd > Cu > Ni for wet season and Co > Zn > Mn > Cu > Pb > Ni > Cd > Fe for dry season; which is as a result of changes in some physiochemical parameters such as acidity, pH, among others. From this result, there is the need to ensure that future health catastrophe is averted from the accumulation and release of Pb2+, Zn2+, Co2+ and Mn2+ especially into the environment.