Spatial distribution of indoor radon in Triveneto (Northern Italy): a geostatistical approach.

The study of spatial distribution of the indoor radon has assumed in the last years a lot of interest. The geostatistical techniques turn out to be particularly promising. The present work presents the results of a study where around 4000 indoor radon data from Veneto, Friuli Venezia-Giulia and Alto Adige, collected during the sampling campaigns performed in dwellings and in schools, have been analyzed. After the definition of the common data set, the study of the spatial distribution of the phenomenon has been performed by examining the experimental variograms. Declustering techniques have been applied. Predictive maps were defined by using simulation techniques; they allow to determine the probabilities of exceeding defined concentration levels, the 'radon-prone' areas. Systematic results regarding the validation of these maps are reported. This methodological study indicates how it is possible to understand the geographical variability of the phenomenon, trying to find out correlations among indoor radon, geological characteristics (i.e. lithology, morphology, tectonics, soil gas) and building-specific features, which can significantly influence radon concentrations.

Radon concentration in waters of geothermal Euganean basin--Veneto, Italy.

Since ancient times the warm thermal waters of Euganean basin, Italy, have been used for therapeutic purposes. The radioactive characteristics, assumed in depth, are due, in particular, to radon gas, which when released during the therapies in the indoor thermal room, determines exposure for the workers. The preliminary results of the project, the purpose of which is to analyze the totality of thermal springs, are presented. The concentrations, obtained by gamma spectrometry, show a high variability, and are comparable to those in other thermal springs in Italy and abroad. Possible correlations with geophysical factors, such as the temperature and depth of springs, have been investigated. A geostatistical analysis of the radon data has also been carried out, through the study of the experimental variogram, obtained by kriging one map of the radon concentration: such an approach is useful not only for mapping but also for giving one possible interpretation of the examined phenomenon through structural geologic characteristics.