HIGH INDOOR RADON CONCENTRATIONS IN AN ALPINE REGION OF WESTERN TYROL

In a village in western Tyrol, Austria (Umhausen, 2,600 inhabitants), unusually high indoor radon concentrations were measured, and the lung cancer mortality rate was found to be higher than that of the total p opulation of Tyrol (620,000 inhabitants). Annual means of radon concen trations were found to be particularly high in the area between the tw o rivers Otztaler Ache and Hairlachbach, geologically an alluvial fan of a giant rock slide of granitic gneisses (area A, median of annual m eans on the ground floors: 1,868 Bq m-3); radon concentrations were co mparatively low in the rest of the village (area B, median of annual m eans on the ground floors: 182 Bq m-3). On the basis of these medians, the annual exposures were calculated according to the ICRP model (are a A: 58.8 x 10(5) Bq h m-; area B: 5.7 x 10(5) Bq h m-3). Data taken f rom the Cancer Registry of Tyrol were used to determine the age- and s ex-standardized lung cancer mortality rate (area A: 6.17; area B: 1.43 ).