Geochemistry of urban soil in the industrial town of Maribor, Slovenia

The first systematic geochemical survey of urban soil in the old industrial town of Maribor, Slovenia, was performed in 2016. Soil properties (pH, electrical conductivity, total carbon, organic matter) and 56 aqua-regia soluble elements were determined from 118 sampling sites. A relatively clear distinction between naturally and anthropogenically distributed elements was found by inspection of the spatial distribution of their highest levels and by applying Spearman rank correlation coefficients. The median levels of Cu, Pb and Zn in the soil are significantly higher than the corresponding Slovenian median levels. Their enrichment is typically found in industrialised zones and the old town centre, suggesting that the elevated levels are historical. In addition, current industrial activities, as well as road and rail traffic contribute to increased levels. Additionally, a few isolated locations with significant enrichment of several elements were identified. Widespread diffuse contamination was not identified. Spatial distribution patterns of many elements (e.g., Co, Cr, Fe, V) are influenced by the geological setting of the area, as their highest soil levels are concentrated at the foot of the igneous-metamorphic Pohorje Mountains.