Trace metals concentrations in soil from different sites in Pretoria, South Africa

Trace metals are common pollutants in urban industrial soils thus making the assessment of these pollutants important especially from developing countries. The present study investigated the level and source of trace metals from different sites in Pretoria in relation to vehicular emission. Soil samples were taken from ten different locations (0-5 and 5-15 cm) in the city and analyzed for trace metal content using Inductive Couple Plasma Mass Spectrophotometer. The values of trace metals from the dust and top soil samples were in the range (in μg g^-1): 12.8-145 for Pb, 33.9-140 for Cu, 43.6-101 for Zn, 0.24-3.49 for Sb, 39.3-97.6 for Fe and 0.09-0.98 for Cd. The result revealed statistically different concentrations for trace metals in all the sites and layers (p < 0.01). Increased concentrations of Pb, Cu, Zn and Sb were witnessed in areas associated high traffic areas. The pollution index revealed that some of the sites were enriched and polluted with metals associated with vehicular emissions. It was concluded from the study that vehicular emission played a significant role in releasing trace metals into the environment. This can pose a serious health risk to humans via inhalation of suspended dust, direct ingestion or through consumption of contaminated food stuff.