Biogeochemical cycling of elements in urban environments differs significantly from natural environments due to high population density and various anthropogenic activities. Because of the complexity of urban environments, a holistic approach to geochemical studies is needed, meaning that contents and occurrences of potentially toxic elements (PTE) in several urban materials are studied by combination of various methods. Soil, attic, household and street dust and solid particles deposited in snow and airborne particles from urban environment of Maribor were studied in presented doctoral dissertation. Characteristics of urban materials and geochemical properties of Maribor were determined. SEM/EDS analyses of airborne particulate matter were successfully introduced to urban geochemical studies. The main mineral in soil is quartz (geogenic origin), in street dust dolomite (winter road gritting) and in attic dust gypsum, which is probably of secondary origin. Determination of 65 element contents in soil and all three dust types revealed that their chemical composition differs significantly. Cadmium, Cu, Pb, Sb, Sn and Zn are predominantly of anthropogenic origin in all studied materials, except in household dust. Additionally, some other PTE in various materials are also of anthropogenic origin. PTE contents are usually highest in industrial zones Melje and Tezno, therefore we assume that they originate from past and present industrial activities. PTE contents are higher in dusts in comparison to soil due to their different origins, differences in physico-chemical properties, anthropogenic influences and different retention times. Attic dust reflects historical influences, street dust reflects mainly influences of present industry and traffic, and household dust influences from the interior of homes. SEM/EDS analysis of PTE-bearing particles in dusts, particles deposited in snow and airborne solid particles showed that angular Fe-oxides predominate in all materials. Cu-Zn and Fe-Cr (Cu, Mn, Ni) shavings are typical for industrial zone Melje. The first particle type probably originates from foundry and the second type from metal furniture factory and foundry. High shares of Fe-oxides and spherical Fe-oxides, often with Mn and other PTE, are typical for industrial zone Tezno. According to the results of presented study, chemical composition of household dust reflects mostly indoor sources and less outdoor influences. Influence of lighter-usage in apartments in which inhabitants smoke was identified. It is reflected in high contents of Ce, Fe and La and occurrence of Fe-Ce-La-O spheres. Bioaccessible fractions (BAF) of PTE differs significantly between different elements, samples and materials. They are mainly higher in stomach than in stomach-intestine phase for soil, street and attic dust. The opposite is true for household dust. The most bioaccessible PTE in stomach phase are Cd, Cu, Pb and Zn, of which the average BAF is often higher than 40 %. The highest BAF in stomach-intestine phase has As, Cd, Cu and Ni.
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