Multielement profiles of soil, road dust, tree bark and wood-rotten fungi collected at various distances from high-frequency road in urban area

Multielemental profiles of soil, dust, linden tree bark (Tilia sp.) and wood-rotting fungi (Schizophyllum commune) collected in central public park of Banja Luka, Bosnia and Herzegovina, at two distances from the nearby high-frequency road, were assessed as potential air pollution indicators. The samples were microwave digested and 10 elements were measured by graphite furnace (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) and cold vapor (Hg) atomic absorption spectrometry. This is the first report on the heavy element contents in the selected type of samples collected in the Banja Luka City and also in Bosnia and Herzegovina. The obtained results showed significant decrease of element contents, particularly of Pb, Ni, Cu, Cr, Fe, Hg, Zn and Co, in the samples with increasing distance from the road edge. According to the Dutch soil quality standard, the Cd, Co, and Hg concentrations of the examined soils were higher than the target values for unpolluted soil, but they were not above the intervention values for which a serious case of soil contamination exists. Compared to the roadside soil, roadside dust had significantly higher contents of Co, Cr, Cu, Pb, Zn and Hg, but majority of them were in the range of concentrations previously reported in literature. The exceptions were Co and Hg, being up to ∼2 times higher than the maximum of the previously reported levels, which might be considered as peculiarity for the Banja Luka dust samples. Dust significantly contributed to the elemental profile of tree bark. The Hg concentration in the roadside tree bark sample was far above the phytotoxic limit, and the problem of “dying trees” in the Banja Luka park previously related to the presence of white-rot fungi could be attributed to the excessive contents of this biotoxic element. Principal component analysis (PCA) and analysis of enrichment factors (EFs) provided a framework for differentiation of dominant sources of elements in the analyzed samples.