Particulate-associated potentially harmful elements in urban road dusts in Xi’an, China Yongming Han a, * , Junji Cao a , Eric S. Posmentier b , Kochy Fung c , Hui Tian d , Zhisheng An a a State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China b Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA c AtmAA Inc., 23917 Craftsman Road, Calabasas, CA, USA d Hangzhou Vocational and Technical College, Hangzhou 310002, China Received 1 June 2005; accepted 21 September 2007 Editorial handling by X.D. Li Available online 15 January 2008 Abstract Sixty five urban road dust samples were collected from different land use areas of 240 km 2 in Xi’an, China. The con- centrations of Ag, As, Cr, Cu, Hg, Pb, Sb and Zn were determined to investigate potentially harmful element (PHE) con- tamination, distribution and possible sources. In addition, the concentrations in different size fractions were measured to assess their potential impact on human health. The highest concentrations were found in the fraction with particle diam- eters between 80 lm and 101 lm, the finest particles (<63 lm) were not the most important carriers for Ag, As, Cd, Cr, Cu, Hg, Pb and Zn. The percentages of these elements in particles with diameters less than 63 lm (PM 63 ) and less than 101 lm (PM 101 ) were in the range of 7–15%, and 30–55%, respectively. Three main factors influencing element distributions have been identified: (a) industrial activities; (b) prior agricultural land use; and (c) other activities commonly found in urban areas, such as traffic, coal combustion, waste dumping, and building construction/renovation. The highest concentrations were found in industrial areas for As (20 mg kg 1 ), Cr (853 mg kg 1 ), Cu (1071 mg kg 1 ), Pb (3060 mg kg 1 ) and Zn (2112 mg kg 1 ), and in previous agricultural areas for Ag and Hg, indicating significant contributions from industrial activities and prior agricultural activities. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction The composition and quality of urban road dusts are indicators for environmental pollution, espe- cially in large cities. Interest in the levels of contam- inants associated with urban road dusts, particularly Pb, has risen in the last few decades (Chatterjee and Banerjee, 1999; Petrosyan et al., 2004; Manno et al., 2006). Reduced cognitive devel- opment and impaired intellectual performance of children (Oskarson et al., 1995) have been linked to Pb exposure. Other elements, such as Cu, Cd, Zn, As and Hg are also well-known toxic elements (ICRCL, 1983; Chatterjee and Banerjee, 1999). Pop- ulations exposed to these elements develop altered 0883-2927/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.apgeochem.2007.09.008 * Corresponding author. Fax: +86 29 88320456. E-mail address: yongming@ieecas.cn (Y. Han). Available online at www.sciencedirect.com Applied Geochemistry 23 (2008) 835–845 www.elsevier.com/locate/apgeochem Applied Geochemistry