ABSTRACT

The effect of automobile emission on the concentration of Pb and Cd in soils and various cassava plant parts along Enugu — Port Harcourt expressway in Nigeria, was studied. Surface soil (0 — 3 0cm) and cassava samples were obtained from sites (Ubakala I, Okigwe I, and shiagu I) close to the expressway location and those far from the expressway otherwise called remote village location (Ubakala II, Okigwe II and Ishiagu II). The phyiso-chemicals properties of the soils, and Pb and Cd levels in both the soil and plant samples were deteimined. The sand fraction was the predominant particle size in all the soils both at the expressway and the remote village locations. The mean sand content in these soils was 63.8 while the mean silt and clay content were14.3 and 21.2 respectively. The soil pH ranged from 5.6 to 5.9. The exchangeable Ca in the soils ranged from 2.00 to 2.80 with a mean value of 2.8. The effective cation exchange capacity of the soils were low and ranged from 4.l3cmol/kg to 8.63cmol/kg. Soils of the expressway location had mean Pb content of 56.25mg/kg which was significantly (P< 0.05) higher than the mean value of 37.49mg/kg obtained for remote village locations. However, significant site x location interaction was also obtained. There was no significant difference between the mean Cd levels of 0.03mg/kg and 0.14mg/kg obtained for expressway and remote village soils respectively. Positive and significant correlation coefficient was obtained between Cd in the soils and Effective cation exchange capacity of the soils. Cassava samples from expressway location had higher mean Pb and Cd levels in the leaves than those of the remote village locations. No significant difference was obtained between the Pb and Cd levels in Cassava pulp and peel in the two locations (Expressway and remote village) studied.