An assessment of lead pollution caused by vehicles emissions in a highly inhabited region of Sofia, Bulgaria

Lead concentrations have been determined in air, soil and vegetation sample s taken along a major boulevard in Sofia town. Concentrations of total susp ended particles (tsp) were also measured. The following concentrations have been found: tsp - 0.168 divided by 1.242 mg/m(3); Pb aerosols - 0.00058 di vided by 0.00573 mg/m(3); Pb in soil - 16.2 divided by 184.3 mg/kg; Pb in g rass - 2.6 divided by 27.4 mg/kg. Tsp concentrations as well as Pb concentr ations in air, soil and vegetation correlated negatively with distance to t he road. Airborne particle Pb is the main source for soil and vegetation po llution. Sequential extraction showed that Pb was bound predominately to CO 32- and only in a small quantity to easily exchangeable phase, to iron and manganese oxides and to organic matter. The results showed that Pb concentr ations in soil meet the maximum permissible concentrations, except for the 5-10 meters adjacent to the road. However, a possibility exists for Pb accu mulation in soil. Planting suitable vegetation and promoting use of unleade d fuel can be proposed as measures to be taken.