Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction

Abstract

In Europe, new cars had to be fitted with catalytic converters since 1993. Besides the desired air quality improvement, an accumulation of the catalytic active noble metals Pt, Pd, and Rh in the environment could soon be observed. This work aimed at a monitoring of platinum group element (PGE) emission and accumulation by comparing analytical data, all generated in 1999 and in 2005 and thus covering an important time span of vehicular exhaust catalysts introduction in Germany. A comparison of analytical results of 2005 with those of 1999 revealed a distinct increase of PGE concentrations in soils closely along heavy traffic roads mainly by a factor of 2–9 in the considered urban area located in northern Germany. At a crowded road in Braunschweig city with stop and go traffic, the highest soil concentrations were determined, namely 261 µg/kg for Pt, 124 µg/kg for Pd and 38.9 µg/kg for Rh. The investigations also revealed that especially Pt and Rh concentrations were comparably elevated in airborne dust in 2005. A sampling at the already mentioned roadside revealed airborne dust concentrations of 1,730 µg/kg for Pt, 410 µg/kg for Pd, and 110 µg/kg for Rh.