Vehicular traffic as a source of pollution: chemical characterisation and analysis of the variation in Sb speciation

Vehicular traffic is a significant source of pollution in urban areas, contributing to both exhaust and non- exhaust emissions. The mechanical abrasion of car and train braking systems releases particles composed of several potentially toxic elements (PTEs): Cu, Fe, Mo, Mn, Sn, Sb and Zn that contribute to air and soil pollution. Among the main PTEs present in brake dust (BD) there is Antimony (Sb), a toxic, non-essential metalloid for living organisms, whose environmental concentrations have tripled in the last 20 years. In the environment, it is present in two different chemical species: antimoniate (Sb-V) and antimonite (Sb-III), and its environmental impact depends on its oxidation state, as Sb-III has a higher toxicity. Possible variations in PTEs speciation, e.g. Sb, allow us to assess their toxicity in environmental matrices and better plan more suitable remediation strategies, including mycoremediation. Soil sampling was carried out at sites adjacent to a railway station, using a core barrel. Chemical characterisation involved ICP-MS analysis of the elemental concentrations in BD and BD-fortified soils at different concentrations (1, 5, 10 and 20 mg g-1) in soluble and insoluble fractions. Thanks to this characterization, for the following applications foreseen by the research project, screening and tolerance tests on the fungal strains isolated from the soil sample will be performed to select the most suitable fungal strains for remediating PTEs-contaminated soils. Moreover, the approach to evaluate the impact on PTEs mobility and Sb speciation will be determined. The speciation of Sb in both matrices will be evaluated using HPLC-AFS.