Toxicity Level of Lead and Cadmium in High Traffic Density Roadside Soils in Selected Towns of East Shoa Zone, Ethiopia

Abstract

Environmental pollution of heavy metals from automobiles has attained much attention in the recent past. The present research was conducted to study heavy metal contamination in roadside soils of East Shoa Zone of Ethiopia. Roadside soil samples were collected from 4 sites (36 soil samples) and analyzed for the concentrations of two heavy metals (cadmium and lead).Soil samples were collected at distance of 0m, 25m and 50m from the roadside. Lead concentration in soil samples was low and ranged from 0.31 to 0.91 mg kg-1. Lead analyses showed that there was no considerable contamination of soil in the study area. Cadmium concentration was the lowest in the soil and varied from 0.11 to 0.43 mg kg-1. These concentrations were below the critical maximum levels above which toxicity is possible. In general, the levels of heavy metals in the roadside soils investigated were low. Both heavy metals exhibited a decrease in the roadside soils with the increasing distance from the road.