Lead accumulation in surface soils and components of Balenites aegyptica specie in a Katsina urban area, Nigeria.

OBJECTIVE The main objective of this paper is to assess the impact of various vehicular traffic densities on lead (Pb) accumulations in some environmental components in Katsina, a semi-arid urban area of Nigeria. METHODS This was achieved by collecting and analyzing samples of surface soils, fruits, kernels, leaves, and barks of Balanites aegyptica from locations of different vehicular traffic densities in the area, and analyzing them for lead, using atomic absorption spectrophotometry. RESULTS The results obtained revealed that the Pb concentration in the high, medium, low, and zero traffic density areas are, 75, 53, 35, and 12 microg x g(-1) respectively for the fruit pulp. They are also16, 13, 8, and 6 microg x g(-1) for fruit kernel and 44, 28, 17, and 9 microg x g(-1) respectively for leaves. For tree barks, the values are 138, 97, 64, and 18 microg x g(-1) respectively while for under-tree-canopy soil samples the mean values are 99, 74, 44, and 17 microg x g(-1). In the case of outside-canopy soil samples, the mean values are 113, 91, 50, and 18 microg x g(-1) respectively for the various classes of vehicular traffic density. CONCLUSION These results indicate a strong influence of vehicular traffic density on Pb emission into surrounding atmosphere and its subsequent precipitation on soil and components of B. aegyptica specie in the area. Of all the samples, tree bark should be the best index of assessing Pb pollution in the area, as it maintains the closest contact with the surrounding atmosphere. Since Pb has no known lower limit for human tolerance, there is an urgent need for Pb pollution control in the area to be effectively enforced.