Assessment of natural radiation exposure from building materials in Estonia

Radionuclides naturally occurring in building materials may significantly contribute to the annual doses of the public. As information on the radioactivity of such materials is lacking, the study of building materials used in Estonia was carried out in order to estimate the annual dose to the Estonian population due to natural radionuclides in building materials. During the study 53 samples of commonly used raw materials and building products were collected and measured. The activity concentrations were determined by gamma ray spectrometry. Their mean values were in the ranges 7-747 Bq kg(-1) for K-40, 4.4-69 Bq kg(-1) for Ra-226, and 0.8-86 Bq kg(-1) for Th-232. The activity index I in the 53 different building materials varied from 0.02 to 0.74 and the radium equivalent, from 6 to 239. The average annual dose for the people, caused by the building materials of dwellings, was assessed for most commonly used materials. It was estimated to be in the range from 0.16 mSv to 0.44 mSv.