Estimations of natural radioactivity levels were carried out for water (surface and groundwater) samples collected from the west bank of the Nile River in Assiut Governorate, Egypt. The activity concentrations in the water samples ranged from 19.20 ± 2.40 to 492.26 ± 71.52 mBq/L, from 15.58 ± 2.62 to 351.39 ± 66.13 mBq/L, and from 50.31 ± 5.58 to 2255.03 ± 249.42 mBq/L for ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively. In this work, the recorded activity concentrations have been organized statistically using a dendrogram cluster and a principal coordinate analysis. In view of the groupings of radionuclide activity, the average annual effective doses through ingestion for adults, children, and infants, despite the responsibility of each explicit radionuclide to the total dose, were assessed and debated. Children had the most important measurement calculations, making them the most regarded mass gathering. All estimations for each different water type, as well as for each individual population group, scored well under the recommended reference value of 0.1 mSv resulting from a one year’s intake of drinking water in accordance with the recommendations of the European Commission (EC) in 1998.

The main purpose of this study was to measure the natural radioactivity in some foodstuffs and agricultural soils from the Abyan Delta in Yemen and study the interaction between soil and foodstuffs by calculating the transfer factor (TF).The annual effective doses to individuals were also calculated and compared with the reference levels. The investigation yielded outcomes that can be considered as the initial phase in the computation of levels of radioactivity for a staple foodstuff in Yemen. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were determined by using the high purity germanium (HPGe) gamma ray spectrometer. In agricultural soils, the mean activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were 33.15 Bq kg⁻¹, 77.25 Bq kg⁻¹, and 1220.59 Bq kg⁻¹, respectively, while the maximum values in foodstuffs were 4.88 ± 0.30, 2.50 ± 0.14 and 351.30 ± 11.25 (Bq Kg⁻¹), respectively. The average TF of ²³²Th and ⁴⁰K were lower than the default values of 0.05 and 1.00 respectively, but the average TF value of ²²⁶Ra was slightly higher than the reference value of 0.04. The average effective dose to individuals from the intake of the food types was 8.448 µSv y⁻¹, which is much lower than the worldwide average annual effective dose.

Determination of the full-energy peak efficiency of a detection system is significant in the activity calculation of the measured radioactive samples. In this work, we present an experimental method to determine the absolute efficiency calibration of a NaI(Tl) detector, considering that a standard source of interest is unavailable and by using the known specific activity of a standard sample measured using a HPGe detector. The efficiency of a gamma-ray spectrometer that consists of a coaxial HPGe detector is calculated using Canberra ISOCS/LabSOCS software and a fabricated calibration source. To validate our method, environmental samples (rock and soil samples) were analyzed on both the detectors. The obtained activity concentrations were checked by means of the IAEA proficiency test procedure. The performance criteria evaluation results were found to be ‘Acceptable’ for all the analytical determinations of all the radionuclides under study, except for the samples with low activity (<15 Bq kg⁻¹ and <10 Bq kg⁻¹ for ²²⁶Ra and ²³²Th, respectively). The precision of the low-activity samples was not considered ‘Acceptable’ as the results were slightly inaccurate; in this case, the results were considered as ‘Warning’ because the relative bias (RB) was less than the maximum acceptable bias (MAB).

The naturally occurring radionuclides (radium-226, thorium-232, potassium-40 and radon-222) were investigated in the alkaline rocks of Abu Khuruq Ring, southern Eastern Desert, Egypt. A high-resolution germanium detector was used for the detection of ⁴⁰K, ²³²Th, and ²²⁶Ra (Canberra, GR4020 model) while ²²²Rn concentration was measured by the Alpha-Guard Saphymo GmbH system, model PQ 2000 (AG). Major and rare earth elements (REEs) were assessed using the inductively coupled plasma mass spectrometry and atomic emission spectrometry techniques. Positive correlations were observed between REEs, indicating symmetrical chemical properties and their overall presence in the parent material—also, a positive correlation was observed between effective radium content and radon concentrations pointing to the strong linear dependency between both contents in the studied rocks. The average values of activity concentration of ⁴⁰K, ²³²Th, ²²⁶Ra, and ²²²Rn were less than the suggested level by a factor of 1.38%, 3.16%, 2.09%, and 1.16%, respectively. Significant variations were found among the radiological hazards parameters, e.g., the mean value of the annual effective dose (0.55 mSv y⁻¹) was more than the global reference value (0.41 mSv y⁻¹) by a factor of 1.34. The calculated average value of the gamma index was 0.90, and that of the alpha index was 0.37. H_ex, H_in and Ra_eq showed fewer average values than the standard values of unity and 370 Bq kg⁻¹, respectively.