Trace element content in urban tree leaves and SEM-EDAX characterization of deposited particles

Leaves of common deciduous trees: Aesculus hippocastanum and Tilia spp. from three parks within the urban area of Belgrade (Serbia) were studied as biomonitors of trace elements (V, Cr, Fe, Ni, Cu, Zn, As, Cd, and Pb) air pollution. Using a scanning SEM-EDAX, the size, size distribution, morphology and chemical composition of individual particles were examined on adaxial and abaxial surfaces of the leaves. Morphological and chemical composition indicated that the most abundant particles were soot and dust with minor constituents such as Pb, Zn, Ni, V, Cd, Ti, As, and Cu. Total element concentrations in the leaves were determined by ICP-OES and ICP-MS. This investigation included spatial, seasonal, and temporal variations in leaves of the selected species. The leaves of A. hippocastanum showed a significantly higher elements concentration and more consistency in trend of element accumulation during the vegetation season in the period 2002-2006 than Tilia spp., so it may be considered as a more suitable species for the assessment of trace element atmospheric pollution, especially Pb and Cu which correlated with the bulk deposition data.