Preliminary Survey of Indoor Radon Concentrations in Portuguese Houses from High Natural Radioactivity Regions

Abstract

Abstract The exploration of uranium ore started in Portugal at the beginning of the century, firstly for the extraction of radium and later for uranium. Radium processing wastes, uranium tailings, and their possible use in buildings contribute significantly to the enhancement of radon levels. A screening survey of indoor radon concentrations is initiated in houses from the granitic region of Beira Alta, in particular in the surroundings of an abandoned radium salts factory, near the mine and chemical treatment installations of Urgeirica, and the town of Guarda. Passive detectors are exposed for periods of one to two months. The preliminary results of this survey programme are presented and discussed. Indoor levels up to the order of 3 x 103 Bq.m-3 have been detected at Urgeirica as well as near the old radium salts factory at Barracao. These concentrations are compared with results for houses from the town of Guarda and also for some houses from the region of Lisbon.