ASSESSMENT OF RADIUM ACTIVITY CONCENTRATION AND RADON EXHALATION RATES IN IBERIAN PENINSULA BUILDING MATERIALS

Radium (Ra-226) is a natural radioactive element of the uranium decay series, which could also be present in building materials. Radon (Rn-222) is continuously produced by the decay of Ra-226 and its presence inside buildings can contribute to the increase of the population exposure to ionizing radiation. In this work, the amount of radium activity concentration and radon exhalation rates in several types of building materials that are commonly used in the Iberian Peninsula have been tested. The radium activity concentration was measured by gamma-ray spectrometry, whereas the radon exhalation rates were carried out using a continuous radon monitor (active measuring technique) and a solid state nuclear track detectors (passive measuring technique). The Ra-226 mean values range from 5.0 to 123.4 Bq kg(-1). As expected, the results show that the radon exhalation rate is higher in granites samples relatively to others building materials analysed. A positive correlation was found between radium activity concentration and radon exhalation rates in both techniques. The emanation fraction and alpha index were also calculated.