Internal platinum and palladium exposure of the general population with emphasis on the exposure from automobile exhaust and dental restorative alloys

Since the introduction of catalytic converters for emission control in automobiles containing platinum (Pt), palladium (Pd), and rhodium (Rh) as effective components, efforts have been made to assess their impact on the environment and on man. Experiments on a test stand showed that Pt is emitted with the car exhaust as Pt(0) and Pt(IV) in the range of ng per kilometer of driving distance (Innacker and Malessa 1992; Konig et al. 1992; Schlogl et al. 1987). Pt concentrations of dust, soil, and grass collected in the vicinity of motorways were found to be elevated (Helmers et al. 1994; Hodge and Stallard 1986; Schierl and Fruhmann 1996, Zereini et al. 1993). The Pt accumulation in soil over the last years is also well documented (Helmers et al. 1994). Furthermore, Waber et al. (1996) showed that Pt concentrations in a standardized grass culture rise with increasing traffic density. So, there is evidence that Pt released from catalysts can be taken up by plants, enter the food chain and contribute to the internal exposure of the normal population.