Platinum and lead in South African road dust

Abstract

Automobile traffic is an important source of pollutants, including lead (Pb) and platinum (Pt). The study presented here aims at assessing current levels of these two metals in South African road dust. Pb and Pt concentrations range from 103 to 1,928 μg/g and 2 to 391 ng/g, respectively. The relatively high Pb concentrations are attributed to the former use of leaded gasoline. In contrast, automobile traffic does not significantly contribute to elevated Pt concentrations owing to the currently limited number of vehicles equipped with a Pt-using catalyst. South Africa is the world’s largest Pt producer and Pt concentrations in road dust were found to depend on the proximity to Pt mines. As leaded gasoline was recently banned in South Africa and automobile catalysts are currently being introduced, Pb and Pt concentrations are likely to change in the near future. Mining emissions are expected to remain significant and their potential impacts need to be assessed.