Bimodal distribution of potentially toxic elements in urban soils: the impact of particle size

The aim of the study was to ascertain the distribution of potentially toxic elements (PTEs) across different soil particle sizes, particularly on Fluvisol soil type in Novi Sad, Serbia, characterised by a significant proportion of sand as coarser particles. PTEs, such as As, Co, Cr, Cu, Mn, Ni, and Pb were analysed in urban soil near major roads. Bulk samples of urban soil were collected and subsequently subdivided into seven different particle size fractions using the wet sieving technique. Based on PTE concentrations and PTE mass loadings, the research confirmed a bimodal binding of PTEs according to soil particle sizes. The highest contribution was observed in the finest fractions ( 50 μm), followed by larger fractions (> 500 μm), while medium-sized particles (50–500 μm) displayed the lowest contribution. Due to the predominant presence of sand in urban soils, it is important to include coarser fractions in risk assessments.