Changes in Palladium, Platinum, and Rhodium Concentrations, and Their Spatial Distribution in Soils Along a Major Highway in Germany from 1994 to 2004

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• 作者：Fathi Zereini ; Clare Wiseman ; Wilhelm Pü ; ttmann
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：January 15, 2007
• 年：2007
• 卷：41
• 期：2
• 页码：451 - 456
• 全文大小：149K
• 年卷期：v.41,no.2(January 15, 2007)
• ISSN：1520-5851

文摘

Soil samples were collected along the highway A5 fromthe major junctions Frankfurter Kreuz to Darmstäder Kreuzfrom July to September, 2004 and analyzed for palladium(Pd), platinum (Pt), and rhodium (Rh). The results werecompared to analyses of platinum group elements (PGE)in soils collected along this same stretch of highway in 1994.The goal of this study is to detect any changes that mayhave occurred in the concentration and environmentaldistribution patterns of these metals over this 10 year period.The concentrations of Pd in soils along the highwaywere found to be about 15 times higher on average thanthose measured in 1994. Pt and Rh concentrations increased2 and 1.6 times, respectively, during this time period.The significant rise in Pd concentrations in soils observedfor the time period of analysis is likely due to its use inautomobile catalytic converters in Germany since 1993. Theresults also show a strong positive relationship betweenPGE emissions and traffic density and speed. The resultsindicate that increases in the concentrations of Pd, Pt, andRh in soils along the highway are not limited to the soilsurface. Pt was measured as deep as 12 cm. Pd wasdetermined at even greater depths of 12-16 cm. Thepresence of Pd at lower depths compared to Pt suggeststhat this element has a higher solubility. Pd, Pt, and Rhconcentrations display a strong inverse relationship withdistance from the road, with decreasing levels with increasingdistance from the highway. Nonetheless, Pd and Ptwere detected in a meadow as far as 50 m from thehighway, a much greater distance compared to that measuredfor these metals in 1994. Pt concentrations were alsofound to significantly correlate with levels of Rh and Pd.The ratios between the PGE analyzed (Pt/Rh and Pd/Rh)display a shift toward Pt and Pd. The results clearlyshow that PGE concentrations have increased over time.Observed increases in Pd concentrations are particularly acause of concern.