Urban airborne particulate matters and dusts can be both ingested and inhaled, causing health damage due to their size, shape and nature of toxic components. Our aim was to characterize the concentration, enrichment and host phases of lead and zinc in total suspended particulate matter (TSP) and settled dust (SD) samples from Budapest, Hungary. TSP samples were collected from the air filters placed in the respiration channels of thermal power stations, while SD samples were collected in glass pots next to a busy street. Detailed mineralogical, chemical and magnetic susceptibility analyses were carried out on these samples. The concentrations of both elements were generally higher in the TSP (330-3597 mg kg-1 for Pb and 1342-19 046 mg kg-1 for Zn) than in the SD samples (58-474 mg kg-1 for Pb and 399-1140 mg kg-1 for Zn). Additionally, they showed moderate contamination in the SD samples, while moderate to heavy contamination in TSP samples with enrichment factors up to 4.9 for Pb and 5.3 for Zn. Transmission electron microscopy (TEM) analyses showed that magnetite may contain significant amount of Zn (up to 2.60 wt%) and Pb (2.50 wt%). However, Zn could be also associated with layer silicates (up to 5.06% by wt) and Ca-carbonates. Moreover, Zn also appeared as major phase constituent in carbonates and oxides. Magnetite particles are resistant to weathering releasing its toxic components slowly to the environment, while layer silicates (and carbonates, Zn-oxides) may be the potential source of mobile toxic metals in the studied materials.
Key words: air pollution, heavy metals, magnetite, clay minerals, urban geochemistry
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