Platinum and Rhodium Concentrations in Airborne Particulate Matter in Germany from 1988 to 1998

Abstract

Increases in platinum group element (PGE) concentrations in ambient air and dust since the introduction of automotive catalytic converters in 1988 is a cause of concern. Until now, data derived from engine-test bench experiments have provided the basis for the assessment of human health risks associated with PGE exposure. Such experiments have provided valuable information regarding emission data that has been used to estimate ambient exposure concentrations. However, these data are not necessarily representative of typical environmental PGE exposure levels and conditions. Data on measured environmental concentrations is needed to provide a more adequate basis for the assessment of exposure and related risks. Twenty air and airborne-dust samples were provided by the Umweltbundesamt (Federal Environmental Agency, Germany) in the years 1988, 1989, 1992, 1997, and 1998. The samples were collected in Frankfurt/Main and the adjacent city of Offenbach. For this, 11 to 80 m3 of air were filtered over a 24-72 h period using a vacuum. Glass-fiber filters were used to collect samples. Sample platinum and rhodium concentrations were determined using adsorptive voltammetry. Although the number of samples collected in different years is limited, the results indicate a trend toward continuous increases in ambient concentrations of these metals between 1988 and 1998. Specifically, there were 46- and 27-fold increases in Pt and Rh concentrations, respectively. Despite these observed increases, the Pt concentrations measured (i.e., 147 pg/m3 on average, with a maximum of 246 pg/m3 in 1998) fell far below 15,000 pg/m3, which has been suggested as a guidance value (i.e., exposure at this level would be expected to be without appreciable health risk). The results of a particle-size distribution analysis of one sample (8-step impactor) that was collected 150 m away from a street show that approximately 75% of Pt and 95% of Rh occurs in association with large particulate matter of > 2 microns, with concentrations reaching a maximum in particles of 4.7 to 5.8 microns. The remaining 25% of Pt and 5% of Rh is present in fine particulate matter of < 2 microns. An approximate 10% of Pt and < 38% of Rh in airborne particles was found to be soluble in 0.1 molar HCl. Further, the results indicate that most of the emitted PGE particles from automotive catalytic converters, particularly those bound to fine particulate matter, are capable of being airborne. As a result, PGEs are not only present in areas close to emissions (e.g., roads), but can be transported over longer distances.

Platinum‐Group Metals

“…The inhalation of these small particles is of special concern due to their uptake by alveolar cells. As an overall trend, it can be seen that PGM concentrations in airborne samples are clearly rising since the introduction of automobile catalytic converters, as demonstrated for the period 1988 -1998 in Germany Zereini et al 2001). Background levels of approximately 2 pg m À3 for Pt in Germany (Rosner and Merget 2000), and below 0.06 pg m À3 for Pd in California (Johnson et al 1976), were described prior to the introduction of catalysts.…”

Platinum Group Elements Enhance the Allergic Immune Response by Acting on Dendritic Cells

“…In this context, halogenated platinum compounds have been identified as potent respiratory allergens leading to rhinitis, conjunctivitis, asthma and urticaria [1]. The toxicologically relevant components of DEP include PLGE [40, 41], but the role of the individual components was unclear. Our data suggest that the activity of PLGE on DC functions is specifically involved in the generation and amplification of the immune response to allergens.…”

Speciation Analysis of Chloroplatinates

“…Determination of platinum in atmospheric aerosols is particularly important in relation to human health because molecules of these metals can enter the human body via the respiratory tract (fraction <10 μm) (Dubiella-Jackowska et al 2007). The detection of total platinum concentrations in environmental matrices requires very sensitive and selective instrumental methods, such as instrumental neutron activation analysis (INAA) (Probst et al 2001), graphite furnace atomic absorption spectroscopy (GF-AAS), electrothermal atomic absorption spectrometry (ET-AAS) (Tilch et al 2000), cathodic stripping voltammetry (CSV) (Zereini et al 2001), inductively coupled plasma mass spectrometry (ICP-MS) (Farago et al 1998;Hann et al 2003;Köllensperger et al 2003;Curtis et al 2010), and inductively coupled plasma optical emission spectrometry (ICP-OES) (Orecchio and Amorello 2011;Van Wyk et al 2011. Objectives of methodological work concern sample pre-treatment procedures for preconcentration and selective and quantitative separation from interfering elements.…”