Evaluation of Heavy Metals Concentration in Soil and Plants as Affected by Vehicular Emission in Alluvial Soil at Middle Egypt Conditions

Road traffic exhaust emissions are one of the most common sources of contaminants to soils and vegetation lies in the vicinity of highways. The main aim of this research is to investigate concentrations of Pb, Cd, Zn and Cu in soil at surface soil depth (0.0 – 30) and subsurface soil depth (30 – 60 cm) as affected by vehicle exhausts along the agricultural highway connecting Cairo – El-Minia City across Beba City, Beni-Suef Governorate, Egypt. In addition, revising the consequences on the staple wheat and maize roadside crops in terms of heavy metals presence in the edible parts for animals and humans. The results show that as the distance from the road decreased the concentration of Pb, Cd and Zn increased to 22, 45, 67, in soils and to 34, 56, 67 in plants, respectively. In general, the limits of heavy metals in wheat and maize plants were safe as stated by WHO (World Health Organization), except Cd (34) in leaves of wheat and maize grown adjacent the road. The pollution incidences, namely, transfer factor (TF), single pollution index (PI) and index of geo-accumulation (Igeo) were calculated and the results indicate that these indices decreased as the distance from the road increased especially in the western side rather than the eastern one. In this concern, this soil was moderately contaminated with Cd, while Pb, Zn and Cu were in the safety level. In conclusion, wheat and corn leaves contain cadmium near the danger limit, so it can be concluded that feeding animals should be prevented by plants grown near highways.