title: Study of road dust magnetic phases as the main carrier of potentially harmful trace elements.
abstract: Mineralogical and morphological characteristics and heavy metal content of different fractions (bulk, non-magnetic fraction-NMF and magnetic fraction-MF) of road dusts from the city of Thessaloniki (Northern Greece) were investigated. Main emphasis was given on the magnetic phases extracted from these dusts. High magnetic susceptibility values were presented, whereas the MFs content of road dust samples ranged in 2.2-14.7 wt.%. Thermomagnetic analyses indicated that the dominating magnetic carrier in all road dust samples was magnetite, while the presence of hematite and iron sulphides in the investigated samples cannot be excluded. SEM/EDX analyses identified two groups of ferrimagnetic particles: spherules with various surface morphologies and textures and angular/aggregate particles with elevated heavy metal contents, especially Cr. The road dusts (bulk samples) were dominated by calcium, while the mean concentrations of trace elements decreased in the order Zn > Mn > Cu > Pb > Cr > Ni > V > Sn > As > Sb > Co > Mo > W > Cd. MFs exhibited significantly higher concentrations of trace elements compared to NMFs indicating that these potentially harmful elements (PHEs) are preferentially enriched in the MFs and highly associated with the ferrimagnetic particles. Hazard Index (HI) obtained for both adults and children through exposure to bulk dust samples were lower or close to the safe level (=1). On the contrary, the HIs for the magnetic phases indicated that both children and adults are experiencing potential health risk since HI for Cr was significantly higher than safe level. Cancer risk due to road dust exposure is low.
authors.affiliation: Department of Mineralogy-Petrology-Economic Geology, School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. Electronic address: annab@geo.auth.gr.
authors.forename: Anna
authors.initials: A
authors.lastname: Bourliva
authors.affiliation: Department of Mineralogy-Petrology-Economic Geology, School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Lambrini
authors.initials: L
authors.lastname: Papadopoulou
authors.affiliation: Department of Geophysics, School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Elina
authors.initials: E
authors.lastname: Aidona
mesh_terms: D002947:Cities; D004391:Dust / Q000032:analysis*; D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data*; D006115:Greece; D006801:Humans; D008280:Magnetics; D019216:Metals, Heavy / Q000032:analysis; D018570:Risk Assessment; D014131:Trace Elements / Q000032:analysis; D014186:Transportation
chemical_list: D004391:Dust; D019216:Metals, Heavy; D014131:Trace Elements
keywords: Health risk; Heavy metals; Magnetic particles; Morphology; Road dust