Considering the importance of environment quality, especially in protected natural areas, we are conducted research of heavy metals contents (Zn, Mn and Fe) in plants and soil at protected natural area "Veliko ratno ostrvo" in Belgrade (Serbia). European white elm (Ulmus laevis Pall.) is native on the Veliko ratno Ostrvo Island and research were conducted in the aim to confirm possibility for using as bioindicator. The Veliko ratno ostrvo island represent unpolluted area, only two samples (total of 5 soil samples) show slightly exceed the value of Zn concentration (site 5 - 288.37 mg.kg^-1 and site 2 - 263.75 mg.kg^-1) in soil, while concentrations of Mn and Fe are in normal range. Concentration of heavy metals in plant tissue is in the normal range, except Fe where there are concentrations over optimal range at 10 trees (up to 415.14 mg.kg^-1) from total 13 tested trees. There are oscillations between different trees i.e. genotypes, which confirmed differences into absorption of heavy metals within species.