An Assessment of the Effect of Automobile Emmission on Selected Roadside Vegetation

Comparative phytoassessment of some selected vegetation exposed to automobile emission along Sapele road, Benin City, Nigeria at different distances from the road was carried out. Three plots (100 cm2 in area) were mapped out at intervals of 10 m away from the road to serve as treatment plots. The plots were designated as A (0 m – 10 m), B (10 m – 20 m) and C (20 m – 30 m) and a fourth plot was the control (100 m – 110 m) plot. Three plants, Sida acuta, Sida garckeana and Mariscus alternifolius; were selected for physiological studies as they were common to all the plots. The leaves of Sida acuta were analyzed for the presence of heavy metals. There was no direct relationship between the results of the growth parameters investigated and distance from the road except for leaf area which increased with increase in distance from the road. For example control, A (0 m – 10 m), B (10 m – 20 m) and C (20 m – 30 m) plots recorded 24.61 ± 1.98 10.60 ± 0.75 15.19 ± 1.68 and 18.05 ± 2.47 cm2 for leaf area of Sida garckeana. Disposal of organic wastes in the immediate environment of the road may have masked the effect of these metals. The plant analysis revealed that there was progressive decrease in heavy metals content of the plant with increase in distance away from the road.