Abstract
Natural radioactivity was measured in samples of pumice used in construction and some other human uses in the Kingdom of Saudi Arabia. The natural radioactivity produced by the elements U-238, Ra-226, Th-232 and K-40 in the selected samples of pumice was determined by high-resolution gamma-ray spectroscopy using the HpGe detector. The results obtained from this study show that the average values of radioactivity concentrations of the elements U-238, Ra-226, Th-232, and K-40 for the pumice are 97.45, 79.03, 73.13 and 521.91 Bq/kg. In this study, we verified the existence of correlations between these radionuclides and the lack of a secular balance of the examined pumice samples. The mean absorbed dose rate regions was calculated to be 103.69 nGy/h, From the results, the average effective internal and external dose and its average value is of 0.13 and 0.51 mSv/y. The equivalent activity of the pumice radium samples, The result of the measurements is that the result of the external and internal risk indicators and the equivalent activity value of all the measured pumice stone samples are within the permissible limits of all the samples measured are within the permissible limits. also the concentrations of the radioactive elements of U-238, Ra-226, Th-232 and (40)Kwhich were evaluated for the all samples under study. The results obtained from this study were studied with the recommended results internationally. In this study, we used some mathematical equation models to estimate the concentration of Rn-222 activity in the air with Ra-226 activities. The Ra-226 activity range was found from 28.4 to 122.6 and mean 79.03 Bq/kg. That is why it is not recommended to use pumice in building walls and to be exposed to it for long periods. Standard deviation was used for all measurement.