Natural radioactivity in some building materials and by-products of Shaanxi, China

The concentration of 226Ra, 232Th and 40K has been determined by γ-ray spectrometry. The measured activity in the selected building materials and by-products of coal fired power plants ranges from 21.5 to 91.3 Bq·kg−1, 15.4 to 63.2 Bq·kg−1 and 83.2 to 683.9 Bq·kg−1 for 226Ra, 232Th and 40K, respectively. The results were compared with the reported data of other countries and with the world average activity of soil. The radium equivalent activities values of all building materials are lower than the limit of 370 Bq·kg−1, equivalent to a γ-dose of 1.5 mSv·y−1. The values of the external hazard index and the internal radiation hazard index are less than unity.