Some adverse effects of human activities on the environment are observed with the development of civilization. Urban centers have a well-developed industrial infrastructure and transportation, hence the presence of numerous and diverse sources of environmental pollution. The aim of the study was to determine the general content of Mn, Zn, Cu, Cr, and Ni in soils and in leaves of some tree species grown in Stalowa Wola, and to determine the trends in their spatial diversity. Soil samples (from the layers 0-25 cm and 26-50 cm deep) were collected at sites located 0.5, 1, 2, 3, 4, 5 and 15 km (control) from the center point (the main gate of the Stalowa Wola Steelworks) to the east, west, north and south. Plant material (tree leaves) was collected from the vicinity of the soil sampling points. The soils were characterized by strong acidity and the prevalence of the sand fraction:  on average above 70% in both layers (0-25 cm and 26-50 cm). The content of microelements in soils from the town was within a wide range: 8÷1778 mg Mn . kg-1, 2.1÷1090 mg Zn . kg-1, 0.9÷61.5 mg Cu . kg-1, 3.8÷77.1 mg Cr . kg-1, 1.2÷56.5 mg Ni . kg-1. The arithmetic mean content of all the investigated metals in soils from Stalowa Wola was more than twice as high (more than 3-fold in the case of Cr and Ni) as the corresponding average values for the checkpoints. There were no clear patterns in the distribution of the analyzed elements depending on the depth. Except for one sample (the Zn content), no excess of heavy metals in the analyzed soils above the permissible levels was recorded. However, according to the IUNG criteria, only 50% of soil samples were characterized by the natural content of heavy metals (0 degree of contamination). Leaves of some tree species were analyzed. The highest accumulation of manganese, an average of 640 mg . kg-1 DM, was found in oak leaves, while the lowest, an average of 4.3 mg . kg-1 DM, occurred in leaves of black locust. Linden leaves were distinguished by the tendency to accumulate chromium (mean 12.3 mg . kg-1), while ash leaves had a particularly high zinc content (mean 98.0 mg . kg-1). Concentrations of the analyzed elements in oak tree leaves from the north-south transect did not present any regular trend in the spatial differentiation.

19.4.2014