Investigation of Heavy Metal Pollution Caused by Vehicular Emissions in Roadside Soils in Ile-Ife

This study determined the concentrations and the variations in the concentrations of heavy metals in roadside soils exposed to regular vehicular emissions in Ile-Ife. The aim was to investigate the levels or extent of heavy metal pollution in roadside soils due to vehicular emissions. Topsoil samples were randomly collected from 10 cm away from each of the seven roadside locations with varying traffic densities. These sites are not industrial areas, and no mechanized farming within any of these locations. Heavy metal concentrations were analyzed using Atomic Absorption Spectrophotometry. Variations in the concentrations of the analyzed metals were compared and analyzed using Analysis of Variance (ANOVA) to test for significant differences in the means, while Duncan's multiple range test was used to separate the means. The concentration of heavy metals in the soils from the study locations revealed that high-traffic areas, particularly location E, exhibited elevated levels of Cu, Zn, and Pb exceeding WHO permissible limits. Lead and cadmium were not detected at location CT. Values obtained from location E were significantly higher (p ≤ 0.05) than those of the other locations. There was variation in the concentrations of heavy metals across the seven study sites in Ile-Ife. The study revealed that roadside soils of places with high vehicular traffic in Ile-Ife are contaminated with heavy metals and can be injurious to human health. The need for adequate governmental policies in the enforcement of laws against the use of leaded gasoline in refineries is hereby recommended.