INDOOR EXPOSURE TO NATURAL RADIOACTIVITY IN VENETO

CRR is the official reference laboratory for the Veneto region for env ironmental radioactivity. In the Frame of the national survey on indoo r exposure to natural radioactivity a regional survey was carried out by CRR. A representative sample of 372 dwellings was selected. The ann ual average radon concentration was 59 Bq.m(-3), the average gamma rad iation absorbed dose rate in air being 76 nGy.h(-1). Statistical analy sis of the results points out that the factors that most affect indoor radon levels are all associated with soil. A simplified geological ma p has been drawn to search for areas potentially at risk. Based on loc al mortality data, calculations are made for comparing the radon risk, estimated according to current international methods, with death rate s from other causes. It is deemed that radon has to be included in the ordinary laboratory prevention activity. So far, most attention has b een focused on the artificial sources of radiations; the related risk, compared with that from radon, at least from the collective point of view, seems to be fairly low.