The implementation of automobile catalytic converters in Austria (1987) has significantly reduced the emission of major pollutants such as carbon monoxide, hydrocarbons and nitric oxides. However, this asset has also led to an increasing emission of platinum group elements (PGE: Ru, Rh, Pd, Os, Ir and Pt) which convert undesirable engine exhaust gases into innocuous compounds. Through thermal and chemical processes Pt, Pd and Rh bound to aluminium oxide particles are eroded from the converter surface, whereby platinum is released into the environment by an approximate rate of 0.5 mg/km. In this way PGEs have accumulated in roadside soils and may pose a future health risk.
The objective of this joint study with the Federal Environment Agency of Austria was to determine the distribution of PGEs in soils along major motorways. This study represents the basis for a future monitoring of PGEs in the environment and should provide a routine procedure for their analysis. Altogether 31 samples were analysed from eight sites across Austria.
At all sampled sites Pt, Pd and Rh significantly exceed natural background values and show decreasing concentrations with increasing distance from the edge of the road. The highest concentrations were measured in the immediate vicinity of the A14 near Rankweil with up to 134 ng/g Pt, 25 ng/g Pd and 13 ng/g Rh.