Fate of traffic borne platinum in the environment

Accumulation of platinum is increasing in the environment over the time. Catalytic converters of modern vehicles are considered to be the main sources of Pt and the concentrations of this metal have risen significantly in the last decades in diverse environmental matrices as airborne particulate matter, soil, roadside dust and vegetation, river, coastal and oceanic environment. Generally, Pt is referred to behave in an inert manner and to be immobile. On the other hand, there is clear evidence of the spread and bioaccumulation of this metal in the environment. Platinum content of road side dusts and aerosol depositions are partly soluble consequently entering the water cycle, sediments, soil, and finally, the food chain. As a matter of fact the mobility and impact of platinum on human health is depending on the chemical form of the metal. For example, the effect of chronic occupational exposure to Pt compounds is well-documented, and chloroplatinates, present at processes in platinum industry and production of cytostatic platinum compounds, are known to exhibit a high allergenic potential. However, the knowledge on the eco-toxicity and fate of these substances in the environment are still very limited. Following the precautionary principle, government agencies in Europe and in the United States are now asserting that the regulation of chloroplatinate sensitization in the workplace, and beyond, should be far stricter, and are proposing new occupational exposure limits for chloroplatinates that are several orders of magnitude below current limits. However, the knowledge on the identity and chemical form of platinum in the different environmental compartments is very limited and the development of powerful and more sensitive analytical methods for speciation, identification and accurate quantification of platinum compounds is therefore highly emerging. The project is specifically focused on the development and innovation of LC and CE-ICP-MS methods to achieve the described issues. From the point of the fate of platinum compounds in the environment, also the influence of microbial activity on their availability in the environment will be assessed. The research will be performed at the Department of Chemistry, University of Natural Resources and Life Sciences, Vienna in the research group of Assoc. Prof. Stephan Hann which has rich experience and excellent analytical equipment in the field of platinum metals ultratrace analysis (reference laboratory for platinum group metals certification in road dust within PACEPAC program) and platinum speciation analysis. This knowledge will be ideally combined with the experience of the candidate regarding biodegradation, environmental pathways and toxicity.

This project was focused on the development of very sensitive (very small amounts of components can be determined) and selective (only components of interest chosen) method of platinum-based compounds in occupational and natural environment. Platinum-based compounds considered in this project are coming from the release from car catalysts during their normal operation. After the release they are present in the surrounding road dust and can be inhaled by humans. By the action of rainfalls, the dust is entering waters and becoming a part of the earth water cycle. Here the compounds undergo various chemical reactions where their character can be changed and they can become more harmful. Besides their presence in the natural environment, these compounds occur in the catalyst and anticancer drugs production plants, where the workers are exposed to these compounds. Their allergenic potential has been already largely described in literature. Considering these aspects, government agencies are proposing new significantly lower limits for these platinum based compounds present in the air. For this reason, very sensitive determination method has been developed within the project. The platinum compounds are determined by the combined method consisting of preconcentration, analytical separation (according to chemical principles) and detection via elemental mass spectrometry (ICP-MS). With the developed method, meeting the newly proposed limits would be feasible. Regarding environmental samples (surface water, underground water, sea water) are platinum concentrations usually very low. Thats why, in another part of the project, the preconcentration has been carried out with real water samples (surface water Danube River). Preconcentration factor of 50 has been reached (50-times higher concentration was obtained by applying the developed procedure) which allowed determination of the present platinum compounds by the elemental mass spectrometry. Overall, the results obtained within this project demonstrates the suitability of the developed methods to be used for reliable determination of the studied platinum compounds in various real samples and so to avoid any harmful effects in the workplace and to improve understanding of their behaviour within environment.