DETERMINATION OF THE LEVELS OF LEAD IN THE ROADSIDE SOILS OF ADDIS ABABA, ETHIOPIA

ABSTRACT: Contamination of the roadside soils of Addis Ababa city by lead, most likely originationg from vehicular exhaust, has been investigated. To this end, soil samples were collected from 14 roadside sites; i.e., 2 samples for shorter and 5 samples for longer roads. Determination of lead was carried out on a total of 45 samples and a control sample collected from a relatively remote area of the city, Entoto Mountains, which was assumed to be free of anthropogenic lead sources. The levels of lead in all the samples were determined using flame atomic absorption spectrometer. The concentration of lead obtained from majority of the sample sites surpassed the maximum limit of the metal in soil recommended by WHO (100 μg/g). The average concentrations of lead in the roadside soils were found to be 418.6 ± 3.4 μg/g. Similarly, the concentration of lead in the control soil sample was 18.8 ± 0.5 μg/g. Although at present the lead content of the gasoline used in the country is 0.013 g/L, the use of leaded gasoline during the past decades is thought to be responsible for the high concentration of lead in the roadside soils of Addis Ababa. Key words/phrases: Addis Ababa, contamination factor, gasoline lead, traffic density, vehicular emissio