Spatial distribution of soil pollutants in urban green areas (a case study in Belgrade)

In urban areas, the presence of toxic microelements in the environment due to the anthropogenic impact (primarily of traffic) poses a serious problem. The negative impact of pollution on populated urban areas is particularly manifest in children. To establish the level of microelement pollution, at 40 localities in the municipality of Stari grad in Belgrade we sampled surface soil near kindergartens and schools during 2013. By applying remote sensing and GIS, small green areas were selected and the spatial distribution of microelements was determined. Because of their different origins and anthropogenic impact, three heavy metals, Cd, Ni and Zn, were examined; the level of soil pollution was assessed by determining their total content, pollution index (Pi), enrichment factor (EF), single risk factor (Ei) and ecological risk index (RI). The highest concentration established was that of Zn, with a mean value of 223.11 mg/kg. The Pi values for Zn (2.96) and Cd (2.98) were similar. Due to the prevailing geological substrate, Ni had the lowest EF (0.75) and Ei (3.09). The effect of the geological substrate on the Ni content was also confirmed by its very high concentration along the banks of the rivers Sava and Danube, while the total contents and factors for Cd and Zn indicated that they were concentrated in the city center. Our results show that 30.72% of the green areas in the city center have a moderate RI, which indicates that the examined pollutants do not present a danger to children.