Measurement of Natural Radioactivity and Radon Exhalation Rate in Granite Samples Used in Palestinian Buildings

The activity concentrations and radon exhalation rates of natural radionuclides were measured for 40 samples of different imported fabricated granite types used in constructing Palestinian dwellings to estimate the radiation exposure in the atmosphere using high-resolution gamma-ray spectrometry. The average activity concentrations for Ra-226, Th-232 and K-40 radionuclides were found to vary from 18.6 to 151.2, 28.8 to 211.0 and 400.0 to 1,256.8 Bq kg(-1), respectively. The overall average activity concentrations for Ra-226, Th-232 and K-40 were 71.0, 820 and 780.8 Bq kg(-1). The average radium equivalents were found to range from 100.5 to 517.6 Bq kg(-1) with a total average value of 248.2 Bq kg(-1). The average absorbed dose rate was estimated at 1 m above ground level and a value of 118.2 nGy h(-1) is obtained. The measured average annual effective dose rates varied from 0.24 to 1.2 mSv year(-1), with a total average value of 0.58 mSv year(-1). The external hazard index measured average values were found to be within 0.27-1.4 Bq kg(-1) with a total average value of 0.67 Bq kg(-1). The radioactivity concentration level estimated values varied from 0.7 to 3.7 Bq kg(-1) with a total average value of 1.8 Bq kg(-1). The radon exhalation rate values range between 3.9 and 30.6 Bqm(-1) day(-1). The effective radium content found to vary from 0.81 to 6.12 with an overall average value of 3.1 Bq kg(-1).