Accumulation of selected trace elements in soil and roadside trees – case study

The aim of the study was (1) the assessment of soil pollution with trace elements along a high-tra ffi c transport route, (2) determination of the content of trace elements in leaves of roadside trees, and (3) comparison of the usefulness of aqua regia with 1 mol dm –3 HCl and 0.01 mol dm –3 CaCl 2 for extraction of phytoavailable forms of Cd, Cu, Cr, Ni, Pb, and Zn from urban soil. The analysis covered contents of trace elements in soil and tree leaves along one of the main transport routes in Warsaw. The analysis of total contents of the studied metals (Cd, Cu, Cr, Ni, Pb, Zn) showed no exceedance of values acceptable for these elements in soil. The analysed tree species were characterised by variable ability to absorb trace elements. Usually White birch ( Betula pendula Roth) accumulated the highest amounts of the studied elements (especially Zn), and Swedish whitebeam ( Sorbus inter-media ) the lowest. The correlation between analysed trace elements concentration in tree leaves and soil suggests that the assessment of these metals pollution of soils is more e ffi cient by means of 1 mol dm –3 HCl than determination of total forms. It was also evidenced that trees can be used for the assessment of the state of pollution of the environment with trace elements.