Distributions of platinum and lead in roadside environment among metropolitan areas in Beijing, China

Platinum and lead have been determined by inductive couple plasma-mass spectrometry (ICP-MS) in roadside dust and plants including Japanese pagoda, Annual grass, Holly and Pine tree collected along main roads in Beijing. The higher Pt and Pb concentrations were found in samples along road with higher traffic volume. Among the plants examined, Pb contents in all selected plants well match with the result in dust. The level of Pt in Annual grass reflects most adequately the pollution of Pt in soil samples. Correlation between Pt and Pb concentrations in environmental sample is established. The sequential extraction was used to study the distribution of species of Pt and Pb. The non-residual fractions of Pt and Pb in urban dust average 26.9% and 71.0%, respectively, and the sum of exchangeable and carbonate fractions presented the amounts of bio-available fraction, only 7.9% of Pt and 8.1% of Pb in urban roadside dust.