MULTI-ELEMENT DISTRIBUTION IN ROAD AND STREET DUST IN THE BITOLA REGION, NORTH MACEDONIA
The results of the systematic study of the spatial distribution of trace metals in road and street dust collected from the streets in the city of Bitola and from the roads in the southern part of the Pelagonia Valley, North Macedonia, known for its coal mine and thermoelectrical power plant (REK Bitola) activities, are reported. The investigated region is covered by a sampling in the four main roads in the direction North-South and East-West. In total, 39 dust samples were collected. Inductively coupled plasma – atomic emission spectrometry (ICP-AES) was applied for the determinations of 21 elements (Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, Sr, V and Zn). Data for the elements contents were proceed using nonparametric and parametric analysis while for the data normalization the method of Box-Cox transformation was applied. The universal kriging method with linear variogram interpolation was applied for the construction of spatial distribution maps of each factor score and the analyzed elements. Based on the results of factor analyses, three geogenic associations of elements (factors) have been defined: F1 (Ni, Cr, Cu, Fe, Co, Mn, Zn, V and P), F2 (Ba, Al, Na and Sr) and F3 (Ca and Mg). The rest of the elements were eliminated from further analysis because they had a low share of communality or low tendency to form independent factors. Even typical potentially toxic elements, such as arsenic, cadmium, lead and zinc, are not isolated into anthropogenic geochemical associations by multivariate statistical methods still show some trends of local anthropogenic enrichment. Thus, the distributions of the arsenic, copper, lead and zinc have higher contents in the road dusts from the north and south parts of the city of Bitola and around of the REK Bitola, showing influence of the industrial and urban activities from the city indicating the distribution of fly ash from thermoelectrical power plant.
Key words: road dust; pollution; heavy metals; thermoelectric power plant; Bitola; North Macedonia