Determination and Speciation Analyses of Potentially Toxic Metals in Oil-Impacted Soils Around Mechanic Workshops for Human and Ecological Risks Assessment

Abstract

Elemental composition and potential toxic metal speciation of the soils around mechanic workshops were determined to assess the contamination status of the study area. Oil-impacted and control soils were collected from the mechanic workshops and uncontaminated areas respectively within Akure, Nigeria. Lead, Cu, Zn, Cd, Cr, Mn, As and Fe concentrations were determined using Atomic absorption spectrometry. Geo-accumulation index results indicated varying degrees of pollution, while contamination factor (CF) results indicated varying degrees of contamination and modified degree of contamination indicated an extremely high degree of contamination by the metals. Pollution load index indicated deterioration of site quality, while potential ecological risk index results indicated very high ecological risks by the metals. Speciation analysis results showed relatively low bioavailability and mobility potential with more proportion retained in the residual fraction for all the metals. The study concluded that the soil around the mechanic workshops were impacted with the analyzed potential toxic metals whose concentrations exceeded those in the control soils and their standard permissible limits.