ASSESSMENT OF RADON POTENTIAL OF SOILS - A 5-YEAR EXPERIENCE

The uniform method for the assessment of radon potential of soils (so- called Radon Risk Classification of Foundation Soils) used in the Czec h Republic is based on determination of soil-gas radon concentration a nd on permeability classification. This paper discusses the results of studies to improve the method based on recent experience. The soil-ga s radon concentrations may vary, often greatly, over small distances. An occurrence of heterogenities often indicates the presence of faults or tectonic zones. Any evaluation based on a single measurement is al most worthless. The sampling depth of 0.8 m represents a reasonable co mpromise between the required reduction of errors caused by the radon variability and the practicability of the method under field condition s. Observed temporal variations of soil-gas radon concentrations may o ften correspond not only to real variations of the measured physical q uality, but also to fluctuations and errors connected with the samplin g and measuring technique. A reproducibility of the radon risk classif ication is satisfactory. Neither a normal nor a log-normal model is ge nerally applicable for a description of soil-gas radon concentration d ata. The field of soil-gas radon concentration measurement is characte rized by a relatively high level of knowledge. More problems are conne cted with the determination of the second main parameter-soil permeabi lity. Copyright (C) 1996 Elsevier Science Ltd.