Establishing geochemical background of elements present in soil and its application in the evaluation of soil pollution based on data collected in the Beskid Sądecki region

The present paper describes problems related to establishing geochemical background. Three selected methods: [Av2], and Tukey Box Plot were applied to establish the geochemical background of soils from the Beskid Sdecki geographical region in southern Poland. The ranges of geochemical background calculated for the following elements: Mg, Ca, Mn, Pb, Cd and As, for 2 sets of data with a diff erent degree of human pressure and sampling area showed considerable diff erences. The results obtained based on a set of samples collected from a stable, regional forest ecosystem seem the most appropriate for establishing geochemical background of large areas. The paper confi rms that the [Av2] method should not be used in the case of data with skewed distribution and a large degree of pollution. Analysing numerous sets of data and several methods also allowed for a conclusion that selecting a single universal method for establishing the background range is impossible. When selecting a method (direct, indirect or integrated), the pollution level of a given area, variability of the tested substance concentration, its geochemical characteristics, data distribution etc. should be taken into consideration. The box plot method eliminates fewer outliers and usually results in obtaining a broader background range. This method should be used mostly for areas with a low degree of pollution and a considerable diversity of element concentration.