Molecule of the Month
February 2005
Anthropogenic Platinum Emission - Investigation of Peat Cores

Temporal change of platinum concentration in the two peat cores.
* 1971: construction and opening of the motor way in Guin (Düdingen)
** 1986: introduction of car exhaust catalysts in Switzerland

The purpose of this study was to develop a robust, reliable and accurate method that allows platinum measurements in the sub-ppt level in complex matrices. This method, successfully applied to the determination of platinum in a wide variety of environmental, food and biological samples, permitted to assess the anthropogenic platinum emission in peat bogs from two locations, one near a well-frequented motorway, one from an alpine site as reference location.
We present the results for the time dependant evolution of the platinum emissions into the environment from analyzed peat cores dated by Pb-210. Samples collected adjacent to the well-frequented highway N 12 Düdingen (Guin) and from the remote area Engadine. (St Moritz) are compared.
The level of enrichment of noble metals in the samples mirrors the introduction of the catalytic exhaust converters in cars. In addition it reflects the traffic load in the respective area. The presented results were obtained by ICP-MS measurements with a high resolution sector field instrument at BAG (Bundesamt für Gesundheit) after acid digestion of the samples in pressure bombs by microwave excitation. Since the toxicity of heavy metals varies enormously as a function of speciation it will be necessary to measure next the chemical form in which the emissions of noble metals occur from exhaust catalysts of cars.

This work was carried out by Céline Fragnière and Max Haldimann in the group of Prof. Urs Krähenbühl.