Relationship between content of stable metals and radionuclides in soils around the largest thermal power plant in Serbia and soil particle-size fractions

Thermoelectric power plants are one of the main polluters of the environment. Power plants Nikola Tesla in Serbia burn lignite containing trace metals and radionuclides to a certain extent. To assess environmental contamination due to power plants operation, concentrations of metals and radionuclides were determined in soil samples of surrounding areas. Concentration of major and trace elements were determined using different spectrometry techniques. Gamma-ray spectrometry was used to determine activity concentrations of natural gamma-emitting radionuclides (40K, 226Ra and 232Th) and 137Cs derived from Chernobyl accident. Soil particle size fractions were determined by the traditional pipette method. To determine the correlation between content of metals and radionuclides in soil and soil particle-size fractions the obtained data were subjected to cluster analysis (CA). Resulting dendrogram identified five clusters. Significant correlations were obtained between Cr, Fe and Co; 40K, silt and clay; 232Th, 226Ra and sand. Weak correlation of Cu, Pb, Cd and 137Cs with other parameters indicated their anthropogenic origin in soil samples. Cesium, clay and Mn were grouped into one cluster which indicated the association of this radionuclide with manganese oxides and clay particles. Results obtained by CA confirmed that multivariate analysis is powerful tool for the assessment of origin of stable metals and radionuclides in areas surrounding thermal power plants.