Survey of the Distribution and Time-Dependent Increase of Platinum-Group Element Accumulation Along Urban Roads in Ioannina (NW Greece)

Abstract

The emission of platinum group elements (PGEs) from automobile catalytic converters has led to rapid increases in Pt, Pd, and Rh concentrations in roadside media. This article represents the first systematic study in Greece to assess PGE levels in road dust and roadside soil and their temporal variation on a seasonal basis over a 12-month period. Road dust and roadside soil samples were analyzed by graphite furnace atomic absorption spectrometry following microwave digestion. Concentrations of PGE in all samples were above the average upper crust values and local background levels, with maximum values of 306.4 ng/g Pt, 18.2 ng/g Pd, and 64.6 ng/g Rh in road dust and 225 ng/g Pt, 14.0 ng/g Pd, and 49.5 ng/g Rh in roadside soil. PGE ratios were not consistent with known catalytic converter composition throughout the sampling period reflecting the high emission of Rh from new catalytic converters. Spatial variations were influenced by various factors like driving style, matrix composition, diurnal change in traffic volume, and climatic conditions. With regard to seasonal variations, systematic changes in the temporal distribution of PGE levels were observed and followed a similar pattern between the two matrices. Except PGEs, Pb levels were determined, since it has been a typical indicator of vehicle-derived environmental lead pollution. The data indicate that despite the use of unleaded gasoline, traffic-related sources of Pb that induce levels above the local background have not been eliminated.

Platinum group elements in urban road dust

“…The results obtained from Newcastle are compared with those of other cities in the world, as shown in Table 4. Mean Pt concentration in Newcastle dust sample (38.2 ng/g) is comparable to those from Ioannina, NW Greece (3.2-306 ng/g) 20 , Scotland (13-335 ng/g) 21 , and Rome, Italy (14.4-62.2 ng/g) 22 . Mean Rh concentration (17.9 ng/g) in this study compares favourably with those of Bialystok, Poland (19.6 ng/g) 23 and Ioannina, NW Greece (6.1-64.6 ng/g).…”

Analytical Determination and Bio-Monitoring of Platinum Group Elements in Roadside Grass Using Microwave Assisted Digestion and Electrothermal Atomic Absorption Spectrometry

“…Nine (9) samples were taken from the same locations within a 10 m sampling grid to minimize random spatial fluctuation. Four (4) sampling locations within the urban settlement of Ioannina city were selected based on preliminary assessment of PGEs in roadside soil and dust in order to reflect urban areas with relatively high traffic burden and low soil coverage (Tsogas et al 2009). One more sampling spot in an old abandoned road located 70 km away from Ioannina with scarce (if any at all) traffic activity was used to collect samples as the reference of the local PGEs background.…”

“…HCl was not considered owing to the interferences observed in the analysis of PGEs with electrothermal atomic absorption spectrometry (ETAAS) after microwave digestion (Tsogas et al 2008). To this end, HNO 3 and HF were evaluated at different concentrations (Tsogas et al 2008;Tsogas et al 2009) using a 3-level experimental design with 2 factors (9 runs À1 block) (Table S1-Supplementary material). T values of 9 M HNO 3 and 12.5 M HF (uncoded values) were decided as a reasonable compromise for the three metal ions.…”

“…), some of which, like Platinum Group Elements (PGEs) are among the least distributed in nature (Pt, Pd, Rh, Ir) (Barefoot 1999;Djingova, Heidenreich et al 2003). Recently, studies have shown the presence of PGEs in urban areas well above the local background levels and proven their direct relationship with increasing traffic activity (Barefoot 1999;Ely et al 2001;Whiteley and Murray 2003;Morcelli et al 2004;Riga-Karandinos, Saitanis, and Arapis 2006;Tsogas et al 2009). Based on these findings, their rareness in nature, and their limited primary anthropogenic sources (mainly mining and smelting), the increasing concentrations of PGEs in the urban environment has been considered as an unambiguous and un-biased indicator of traffic-related pollution Zechmeister et al 2006).…”

“…Based on these findings, their rareness in nature, and their limited primary anthropogenic sources (mainly mining and smelting), the increasing concentrations of PGEs in the urban environment has been considered as an unambiguous and un-biased indicator of traffic-related pollution Zechmeister et al 2006). On a short-term basis, their presence can be monitored by measuring their residues in soil and roadside dust (Whiteley 2005;Tsogas et al 2009) while medium to long term accumulation can be approximated through sampling and analysis of specific indicators like roadside grass and respective flora (Riga-Karandinos and Saitanis 2004;Dan-Badjo, Rychen, and Ducoulombier 2008).…”