Heavy Metal Concentrations in Road Deposited Dust at Ketu-South District, Ghana

Increasing air pollution levels due to rapid urbanization and growth in vehicular emission have become a major source of concern. As a result, research on air pollution in urban environments has largely focused on road deposited dust. In the present study, road deposited dust samples collected from the Ketu-South District, Volta Region in Ghana were analyzed for heavy metals (As, Cr, Cu, Mn, Ni, Pb and Zn) using energy dispersive XRF. The ranges of metal concentration were: 0.4-18.2 μg/g for As; 284-9106 μg/g for Cr; 18.4-144.1 μg/g for Cu; 233-1240 μg/g for Mn; 12.3-493.2 for Ni; 3.1-67.8 μg/g for Pb; and 18.2-406.5 μg/g for Zn. The highest level of metal contamination was found in the only roadway of an industrial area (cement factory). The lowest contaminated site was noted in a roadway which runs through a host of rural communities. Inter-cities comparison with previous data established that Cr levels in the present study was very high while Pb was very low compared to other cities. Metal contamination assessment status of the metals was made using mathematical models in terms of enrichment factor, geoaccumulation index and contamination factor. All the models agreed that contamination levels is in increasing order of Mn>Ni>Cu>Pb>Zn>As>Cr.