Platinum Group Elements in Birds of Prey

Doctoral thesis, 2005

The environmental concentrations of Pd, Pt and Rh (three of the platinum group elements, PGE) have increased since the introduction of exhaust catalysts on automobiles. A limited understanding of the environmental distribution and effects of the platinum group elements has raised concern over their potential biological availability. To date, no research has been performed on the extent of and routes for PGE contamination in free-living animals at the top of food chains. This thesis presents the first results for PGE concentrations in birds of prey living in their natural habitat. A temporal increase of PGE concentrations in feathers from birds of prey, which is closely associated with the introduction of automobile catalysts, was found. Evidence is presented that PGE deposit on the feather surface as sub-micrometer airborne particles emitted from automobile catalysts. In contrast to Cd, Cu, Pb and Zn, PGE do not contaminate feathers internally from the blood. Palladium and Pt concentrations were significantly higher in feathers from birds dwelling close to the ground in urban areas compared to feathers from birds at a higher trophic level and birds with rural habitats. Baseline concentrations at the low ngg-1 level of Pt and Rh in sampled materials from birds of prey demonstrate that there is no biomagnification of PGE. In contrast to metals such as Cd, Cu and Zn, ingested or inhaled PGE does not result in a high PGE load for internal tissues such as liver and kidney, although slightly elevated levels in blood and liver indicates that PGE can be taken up internally in birds of prey. For Pd, however, results present tentative evidence of a higher mobility and possibly bioavailability compared to Pt and Rh.