RADON EMANATION OF SOILS FROM DIFFERENT LITHOLOGICAL UNITS

In soil samples collected from 58 points over 7 different lithological units most often appearing in Slovenia, at which radon in indoor and outdoor air and in soil gas had been measured in previous surveys, emanation fraction of Rn-222 has been determined. The number of samples for a unit differed and was the highest for carbonates which cover more than two thirds of the country. Emanation fraction differed significantly from unit to unit, as well as from sample to sample within the same unit. The following ranges and averages were obtained: 0.015-0.079 and 0.035 +/- 0.016 for alluvial and glacial deposits, 0.014-0.306 and 0.089 +/- 0.085 for elastic sediments containing clay, 0.027-0.084 and 0.056 +/- 0.040 for coarse clastic sediments, 0.016-0.114 and 0.053 +/- 0.037 for flysch, 0.010-0.547 and 0.186 +/- 0.178 for carbonates, 0.016-0.041 and 0.029 +/- 0.018 for metamorphic rocks, and 0.262-0.418 and 0.340 +/- 0.110 for sea and lake deposits. Correlation of the emanation fraction with the radium concentration in soil and radon concentration in soil gas showed correlation coefficients of 0.56 and 0.26, respectively.