Concentrations and resulting doses of natural radionuclides of building materials of Beijing

The concentrations of 232Th, 226Ra and 40K of 34 kinds of building materials of Beijing were analysed with a plastic anticoincidence gamma sepctrometer with a NaI(Tl) of Φ75 x 75 mm. The average values of cotents for these three kinds of nuclides were (24 ± 19), (40 ± 83), and (5.5 ± 3.6) x 102 Bq/kg, respectively. The derived concentration of indoor radon in Beijing from the concentration of 226Ra in building materials was 29 Bq/m3. Annual effective dose equivalent from natural radiation to public in Beijing was estimated to be 1.8 mSv, of which 1.5 mSv was from the radiation indoors