title: Platinum group element and cerium concentrations in roadside environments in Toronto, Canada.
abstract: Platinum (Pt), palladium (Pd) and rhodium (Rh) are accumulating globally in the environment, due to their use as catalysts to control automotive exhaust emissions. While environmental increases in platinum metal concentrations have been well documented for a number of countries, published data for Canada have been missing to date. The aim of this study is to examine the concentrations of Pt, Pd and Rh, as well as Ce, in soils and dust as a function of traffic volume in Toronto, Ontario. Soils and road and underpass dust were collected from two sites with medium and high volumes of traffic. Samples were acid digested and co-precipitated with Hg (for Pd) and Te (for Pt and Rh), prior to measurement using ICP-Q-MS. Palladium occurred at the highest levels in samples, followed by Pt and Rh. Median concentrations for all soil samples were 63 μg Pd/kg, 8.7 μg Pt/kg, 1.7 μg Rh/kg and 41 mg Ce/kg. The results support existing data regarding PGE accumulation trends in urban and roadside environments, due to their use as catalysts in automotive catalytic converters. This study also confirms a shift toward the heavier use of Pd as the catalyst of choice in recent years, as reflected in the higher concentrations measured for this metal relative to Pt and Rh. The results highlight a need to continue monitoring the accumulation of PGE, most notably Pd, in urban environments.
authors.affiliation: School of the Environment, University of Toronto, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, Toronto, Ontario, Canada. Electronic address: clare.wiseman@utoronto.ca.
authors.forename: Clare L S
authors.initials: CL
authors.lastname: Wiseman
authors.affiliation: Institute for Atmospheric and Environmental Sciences, Department of Environmental Analytical Chemistry, J.W. Goethe University Frankfurt, Frankfurt am Main, Germany.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Hassan Pour
authors.affiliation: Institute for Atmospheric and Environmental Sciences, Department of Environmental Analytical Chemistry, J.W. Goethe University Frankfurt, Frankfurt am Main, Germany.
authors.forename: Fathi
authors.initials: F
authors.lastname: Zereini
mesh_terms: D002563:Cerium / Q000032:analysis*; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring; D009864:Ontario; D010165:Palladium / Q000032:analysis*; D010984:Platinum / Q000032:analysis*; D012238:Rhodium / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D001335:Vehicle Emissions
chemical_list: D004391:Dust; D012989:Soil Pollutants; D001335:Vehicle Emissions; D002563:Cerium; D010984:Platinum; D010165:Palladium; D012238:Rhodium
keywords: Cerium; Palladium; Platinum metals; Rhodium; Soils; Traffic