The level of natural radioactivity in 20 black sand and 20 sediment samples collected from Temsah Lake beaches of Suez Canal district, Egypt was investigated. The gamma-ray spectrometry system with hyperpure germanium (HPGe) detector has been used to determined radioactivity concentrations. Mathematical model is used to estimate the activity concentrations of 222 Rn in the air with the activities of 226 Ra. The activity concentrations of the sediment and black sand samples range from 4.29 ± 1.66 to 30.06 ± 8.80 and 4.29 ± 0.68 to 18.52 ± 5.22 Bq/kg) for 226 Ra. The ranges of radioactivity concentration of 232 Th vary from 6.69 ± 1.54 to 39.24 ± 9.80 and 4.56 ± 1.07 to 18.65 ± 5.27 Bq/kg. The effective annual dose rate in the samples under study varies from 0.01 to 0.05 mSv/y for sediment samples and from 0.01 to 0.05 mSv/y for black sand samples. The concentrations of radon gas in the air were determined as well as the activity concentrations of 226 Ra. Radon 222 Rn doses from gas inhalation for humans were estimated to be in the range of 0.13e13.09 msv/y for all samples. The activity concentrations of all samples, which were measured in the present work, were compared with the values in other countries in the world, and it was found they were within the permissible limits, which indicates that the study area was radiologically safe for humans.

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Fourteen samples of marble were collected from different factories in Egypt. The samples were crushed, dried in controlled furnace for around twenty four hours, and then stored for five weeks in plastic Marinelli beakers. Concentrations and the U-and Th-bearing minerals were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS).The gamma radiation of the samples was measured, employing high resolution γ-ray spectroscopy with an accumulating time for about 80000 sec. each. From the measured γ-ray spectra, activity concentrations were determined for marble samples 226 Ra (37. 6 ± 1.7 -100.54 ± 3.2 Bq/kg), All obtained results referred to the fact that all the concentrations were within the allowed limits to domestic use. Comparing the results in this work with those published by International Atomic Energy Agency and local and universal researches, it was found that these concentrations were within the allowed limits for agricultural and domestic uses.

The concentrations of 238 U (226 Ra), 232 Th, and 40 K for the commonly used decorative building materials (15 marble and 15 ceramic) in Egypt were measured using gamma spectroscopy system. Radionuclides concentrations in marble samples were ranged from: