This study evaluated heavy metal concentration on sampled plants (Pennisetum purpureum) resulting from exhausts fume pollution from vehicular movement along, the busiest inter-state route in Nigeria, the Lagos-Ibadan Expressway. At interval of 5 km from 7Up Bus Stop in Lagos to Ibadan Tollgate, samples of P. purpureum were collected at 5 m, 15 m and 25 m away from the edge of the road into the forest. The heavy metal concentrations in the P. purpureum samples, collected during both dry and wet seasons, were determined using Atomic Absorption Spectrophotometer (AAS). The heavy metal concentrations from sampled plants during dry season in mg.kg-1 are Zn (45.68, 3.05), Cu (25.95, 1.19), Pb (4.19, 0.17), Cr (3.99, 0.40), while during wet season are Zn (42.63, 1.96), Cu (21.73, 0.43), Pb (3.12, 0.00) and Cr (3.00, 0.00). The results indicated a general reduction in heavy metal concentrations in the sampled P. purpureum collected during rainy season, when compared with sampled P. purpureum during dry season at 5 m, 15 m and 25 m from the road edge. Transfer Factor revealed a poor response in the absorption of majority of the heavy metals from soil to plant as all the values of Transfer Factor for all the heavy metals were less than 1. The research results showed that Lagos-Ibadan Expressway is heavily polluted with Fe, Mn, Zn, Pb, Cu and Cr as the major heavy metal pollutants found in plant during dry and wet seasons resulting from vehicular exhausts emissions along Lagos – Ibadan Expressway.
Key Words:Transfer Factor, Heavy Metals, Pennisetum purpureum, Pollution