Road Dust Resuspension in a Coastal Atlantic Intermunicipal Urban Area with Industrial Facilities: Emission Factors, Chemical Composition and Ecotoxicity

Road dust resuspension in urban environments can be both a means of transport of pollutants across the various environmental compartments and a source of pollutants itself, becoming a potential threat to human health. With the aim of obtaining emission factors and achieving a detailed chemical characterisation of road dust (RD) in typical Portuguese cities, a sampling campaign was performed in the region of Aveiro. Locations were chosen for intercomparison in various urban environments with different land uses, from the busier city centre and university campus to residential neighbourhoods and harbour-commercial areas with industrial activities. PM10 samples were analysed for organic and elemental carbon (OC and EC) by a thermal-optical technique, elemental composition by PIXE, organic speciation by GC-MS, and ecotoxicology by a luminescence inhibition bioassay with Aliivibrio fischeri. A health risk assessment for elements and PAHs was carried out. Dust loadings of 1.9 +/- 1.8 mg PM10 m- 2 were registered overall, whereas in the most trafficked areas of city centre they reached more than three times the average. OC accounted for 6.5-15.5% of total PM10, but element oxides represented the largest mass fraction (61.4 +/- 8.6%). A strong enrichment was detected mostly for typical traffic-related elements such as Cu, Zn, As, Br, Cr, Ni and Mo and interestingly, Rb and Se. The analysed organic compounds accounted for 3.66-11.0 mg g-1 PM10, including PAHs and aliphatics, with a clear dominance of plasticisers. Some other compounds attributed to non-vehicle sources, such as fatty acid alkyl esters, were also detected. As concerns the 16 priority PAHs, their total mass concentration ranged from 5.58 to 36.3 mu g g-1 PM10, with clear variability between sampling spots. All samples caused an ecotoxicological reaction in the bioassay, but samples from harbour and commercial areas proved to be most toxic.