Assessment of heavy metals (Pb, Cd, Zn and Cu) concentrations in soils along a major highway in Wukari, North-Eastern Nigeria

Abstract

Heavy metal pollution is a major environmental problem, especially around highways with high traffic density. This study investigates the levels of Pb, Cd, Zn and Cu in roadside soils of Wukari section of the Wukari-Jalingo highway, Taraba state, Nigeria. Samples were randomly collected and analyzed using standard methods. The mean concentrations (µg/g) of Pb, Cd, Zn and Cu from all sample sites ranged: 89.6-247.0, 0.15-5.3, 26.8-163.0 and 7.1-61.2 respectively. The extent of the heavy metals contamination was assessed, as analytical data were subjected to pollution calculation methods. The contamination factors (CF) reveal extreme contamination of the sites and an increasing trend in the heavy metals concentrations was observed in sites with more human activities. The pollution load index (PLI) showed that the sites are severely polluted as the PLI of the metals from each sample site exceeded the PLI of the background (control) sample (0.7). Spearman’s rank correlation analysis showed clear correlations (p<0.001) amongst the metals suggesting a common source. It can be concluded that the study sites pollution is mostly due to automobile emissions. This study provides awareness for residents to avoid activities such as farming, trading etc very close to the highway due to exposures to these toxic metals. *Corresponding Author: Achadu, O.J  ojodomo2000@yahoo.com