A study on the extent to which lead and cadmium from motor vehicles have contaminated roadside soils and vegetation in Nairobi and Kiambu, Kenya.

Abstract

The lead and cadmium concentrations in roadside soils and grass from six sites in Nairobi and four sites in Kiambu were determined by atomic absorption spectrometry. Results showed that both soil and grass contained the metals studied. Linear regression analysis between concentrations of metals in the samples and traffic volumes of sites revealed, the two were strongly correlated, thus indicating that motor vehicles form a major source of lead in the roadside. For cadmium there was no significant correlation between concentration and traffic volume. The cadmium concentrations did not show any clear variation with distance away from the roads.