On the issue of choosing the background concentrations of chemical elements in the epiphytic lichens

Abstract

The relevance of the research. For comparison of data obtained in studies of polluted urban areas, it is necessary to have background levels of concentrations of the identified chemical elements in environment. The main aim of the study is to evaluate the influence of ecological and geochemical factors on the levels of accumulation of chemical elements in epiphytic lichens collected in areas practically unaffected by anthropogenic activity. The methods used in the study: the method of instrumental neutron activation analysis (data on 28 chemical elements in the ash of lichens); statistical analysis. The results. It was determined that the lichen chemical composition reflects natural geochemical features of bed rocks and soils in the territory of their growing. The data indicate a fairly close levels of accumulation, which is defined as the confidence interval of defining 16 elements such as La, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Th, Sc, Fe, Co, Ca, Na, Rb, Cs, and group of 12 elements: Cr, Zn, As, Br, Sr, Ag, Sb, Ba, Nd, Ta, Au, U, for which there are more significant differences in the assessment of their average for each of the background regions studied. Elemental composition of the epiphytic lichens on Tomsk region was recommended as regional background for Siberia. This area is characterized by negligible industrial influence and by absence of geochemical anomalies of bed rocks and underlying surface.

Keywords

• atmosphere pollution
• background areas
• concentrations of chemical elements
• epiphytic lichens
• predominance of natural geochemical factor