Distribution of emanation fraction with respect to the
lithological units is shown in Fig. 3 and summarised in
Table 3. The highest values, with the widest range, were
observed in samples over carbonates covering more than
two thirds of the south-west part of the country, which is
crossed by a number of tectonic faults (cf., Fig. 1). The
highest emanation fractions are ascribed to radium atoms
adsorbed on the surface of nanoparticles [34]. Differences
within some lithological units (e.g. C—carbonates, B1—
clastic sediments containing clay) are even bigger than
between units, but are in narrow range in others. Statistics
for B2, D and E is not justified because of small number of
samples assigned to these lithological units. By applying
Kruskal–Wallis ANOVA test, which is a nonparametric
method for testing the equality of different samples’ medians