Assessment of radon-222 concentrations and exhalation rates of rocks and building materials

One hundred samples were collected from two regions (Bir El-Sid and Wady El-Gemal ) in the Nile Valley. It contain various types of igneous and metamorphic rock samples (acidic dykes, intermediate dykes, basic dykes, serpentinite, metagabbro, menalge). Another set of samples were collected from different regions of Germany. Samples were analyzed and the concentrations in Bq/kg dry weight of radium were determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. A direct method is used to measure 222 Rn emanated from the samples, which was analyzed in laboratory using the portable radon monitor Prassi. 222 Rn activity concentrations (Bq/m 3 ) were in the range from 36.1± 2 to 96.4 ± 6, 17.8 ± 3 to 73.6 ± 4 and 18.0 ± 2 to 188.1± 15 Bq/m 3 for samples collected from Bir Elsid, Wadi El-Gemal and samples from Germany respectively. The corresponding values of exhalation rates were from 0.0012 to 0.004, 0.005 to 0.015 and 0.007 to 0.0069 Bq/gs for these areas respectively.