Platinum group elements in urban road dust

Introduction of catalytic converter in our automobiles played a vital role in the reduction of harmful emissions such as carbon monoxide, volatile organic compounds and oxides of nitrogen. The three-way catalytic converter which consists of platinum (Pt), palladium (Pd) and rhodium (Rh; Pt–Pd–Rh), while reducing harmful emissions also increases the concentration of platinum group elements (PGEs) into the environment. This situation is due to the deterioration of the surface abrasion of the catalytic converter, thus releasing the PGEs adsorbed in small particles into the environmental compartments of air, soil and water. In this study, the concentration of PGEs in the environment was investigated using road dust collected from the city of Newcastle upon Tyne as a case study. The results obtained using ICP-MS revealed an elevated concentration in PGEs in the road dust in comparison to the lithospheric average. From the study, the average concentration is as follows: platinum = 38.23 ng/g, palladium = 79.8 ng/g and rhodium = 17.56 ng/g. The average concentration of PGEs in the lithosphere is 5.0 x 10–6 ng/g for Pt, 1.5 x 10–5 ng/g for Pd and 1.0 x 10–7 ng/g for Rh