Rilascio di radon: problematiche di rilevamento e valutazione dei fattori di rischio

Internationally the indoor radon exposition as health hazard is widely recognized; so specific laws and regulations have been introduced in many countries and so-called radon - risk maps have consequently been produced. In Italy the radon exposure legislation regards only general workplaces (D. Lgs. n. 241/00) and the only national survey was conducted in the 90’s by APAT, ISS and ARPA regional agencies; this survey evaluated the exposure to indoor radon in national dwellings on large scale. Failing guidelines, only few Italian Regions have started surveys for the identification of “radon prone areas” but with independent standards and protocols and this involved a bigger uncertainty on the definition of a national risk map. In the present work a standardized methodology for indoor radon measurements has been set up; especially the developed passive measurement tecnique has been validated through an intercomparison with international laboratories. A radon indoor monitoring survey has been conducted countrywide and 5425 data have been elaborated to produced a map of the annual average radon concentration in the Italian Regions and moreover we verified the relapse of seasonal fluctuations on radon concentrations. We georeferentiated the data obtained in the Italian Regions with the largest number of samplig (Lombardia, with the case studies of Milano Province and Milano city, Emilia Romagna, Toscana, Puglia) and we elaborated these data using geostatistical technique in order to produce distribution maps of the annual average indoor radon concentration. Appling the approach recently utilized internationally, we have integrated the elaborated maps with the geological knowledges of the high concentration macro-areas identified in this work in order to better determine them. This study has allowed to point out not negligible radon concentrations also in traditionally no–risk zone; moreover the application of the developed methodology will be useful to give advices in order to fill legislation gaps or to draft urban development plans.