Antimony as a traffic-related element in size-fractionated road dust samples collected in Buenos Aires

The growing interest of public opinion in environmental problems conducted us to investigate the levels of a toxic traffic-related element such antimony in 19 size-fractionated street dust samples. Samples were collected in the megacity of Buenos Aires during two months at 19 sites with different urban characteristics and traffic profile. Samples were sieved in four fractions (F1 <37 mu m, F2: 37-55 mu m, F3: 55-75 mu m and F4: 55-100 mu m) before elemental analysis. A mixture of aqua regia and hydrofluoric acid was used to digest all samples. Antimony concentrations were quantified by inductively coupled plasma optical emission spectrometry (ICP OES) or flow injection hydride generation-atomic absorption spectrometry (FI-HG-AAS). Twenty four out of 73 sub-samples analyzed showed Sb levels <0.05 mu g g(-1); in the rest of the samples mean Sb concentrations varied from 1.4 to 20.4 mu g g(-1). Maximum and minimum concentrations (in mu g g(-1)) found in individual samples in the four fractions were: Fraction 1, <0.05-20.4; Fraction 2. <0.05-18.4; Fraction 3, <0.05-63; Fraction 4, <0.05-7.7. Antimony was found to be enriched in the smallest size fraction of road dust, with mean enrichment factors varying between 27 (F3) and 272 (F1). Concentrations of Sb were correlated with those of other traffic-related elements such as Cu and Pb and higher levels were found in areas with medium and high traffic densities. (C) 2010 Elsevier B.V. All rights reserved.