Evaluation of urban contamination with trace elements in city parks in Serbia using pine (Pinus nigra Arnold) needles, bark and urban topsoil

Urban environments are strongly influenced by anthropogenic activities, which are often reflected by a high degree of contamination in relation to the natural environment. Concentrations of five trace elements (B, Cr, Cu, Mn and Zn) were determined in the surface layers of soil (0–10 cm), bark, and 1- and 2-year-old needles of Pinus nigra Arnold in urban parks in four cities in Serbia exposed to different pollution sources. The sampling locations in parks were chosen based on their proximity to industrial complexes and heavy traffic. Soil indices such as the contamination factor and the degree of contamination were used to assess the potential ecological risk in urban topsoil. Although some metal concentrations (Cr, Cu, Mn and Zn) occasionally exceeded the background values, they posed no threat to the environment. The content of the selected metals in needles varied depending on the metal, the age of the needles, and the site. It is evident from this study that pine needles do not accumulate trace elements in large (mg kg−1) quantities. The highest metal accumulation was observed in the soil and needles at sites with heavy industry and heavy traffic, such as Smederevo and Belgrade, which were the two most polluted sites