Time-dependent increase of traffic-emitted platinum-group elements (PGE) in different environmental compartments

During the past decade, the traffic-related emission of Pt, Ph, and Pd has strongly increased resulting in growing concentrations in specific environm ental areas. To distinguish different aspects of time-dependent development , PGE (platinum-group elements) concentrations and element ratios in urban dust; road-dusts, soil, and sewage sludge samples collected over the past d ecade were determined. The short-term variation of PGE concentrations and e lement ratios in road dust is due to wind and rain, whereas the long-term t rend reflects the changing proportions of PGE used for converter production . At a typical urban site the daily deposition rate of Pt in airborne dust is up to 23 ng m(-2). In soil, the total input of PGE has been accumulated since the introduction of converter technology. Because of very low backgro und values, this contamination results in rapidly increasing PGE concentrat ions, showing multiplied values over a period of 2 years at a typical highw ay site. The integration of these data permits an estimate of the total acc umulation of PGE and mean emission rates that are significantly higher than experimental results from stationary motor experiments. Runoff contributes to the composition of sewage but seems to be less important, compared to o ther sources, in total PGE input into urban sewage sludge.