『Abstract
　This investigation represented the preliminary study to characterize Pt and Pd concentrations and enrichment ratios in urban roadside soils. Roadside soil samples were analyzed by ICP-MS. Data from 21 roadside topsoil samples show medians of Pt and Pd concentrations are 2.9 and 2.8 ng g^-1, respectively. These values are higher than those of upper crust that average 0.4 and 0.4 ng g^-1, respectively. The relatively lower Pt and Pd concentrations are expected due to recent introduction of catalysts to China compared to the prolonged use of catalysts in Europe. Hierarchical clustering analysis indicates that Pt and Pd in Xuzhou urban roadside soils were mainly from the traffic emissions. Computation of enrichment ratios using the upper crust values as background levels suggests that the roadside soils had enrichment medians of 6.4 for Pt (range 2.5-11.75) and of 6.75 for Pd (range 2.75-9.25). Lower Pt/Pd ratios (range 0.35-2.86) in relation to similar studies in other countries were observed due to the different automobile calalytic converters. In general, fine fraction (＜250μm) contains higher Pt and Pd concentrations compared to the coarse fraction (250-500μm).

Keywords: Pt; Pd; Urban roadside soil; Hierarchical cluster analysis; Xuzhou』

Introduction
Minerals and methods
Results and discussion
　Pt and Pd concentrations
　Enrichment factors (EFs)
　Hierarchical clustering analysis
　Grain size fractions
Conclusions
References