AlphaGUARD radon gas analyzer and NaI (Tl) spectrometer were used to measure the concentration levels of ²²²Rn and, ²²⁶Ra, ²³²Th, and ⁴⁰K respectively in 109 groundwater samples collected from four different districts in Qena governorate, Egypt. The average values of the activity concentration were 3.57 ± 0.08, 0.54 ± 0.03, 0.40 ± 0.03, and 5.10 ± 0.44 Bql⁻¹ for ²²²Rn, ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively. The average values of ²²²Rn, ²²⁶Ra, and ²³²Th are lower than, 100, 1, and 1 Bql⁻¹, respectively, the WHO recommended permissible levels for drinking water. For radiation exposure assessment, the annual effective doses due to ingestion of ²²⁶Ra and ²³²Th and inhalation of ²²²Rn for adults were determined and compared with the reference limits. The annual effective doses due to ingestion 139.21–201.34 µSvy⁻¹ are higher than the public annual dose limit 100 µSvy⁻¹ recommended by WHO. These indicate that the ingestion of groundwater from the study areas might pose radiological health hazards.

Instrumental neutron activation analysis was used to study geochemical peculiarities of the Siwa Oasis in the Western Egyptian Desert. A total of 34 elements were determined in soil and sediment samples (Na, Mg, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, I, Cs, Ba, La, Ce, Nd, Eu, Tb, Dy, Tm, Yb, Hf, Ta, Th, and U). For data interpretation Cluster analysis was applied. Comparison with the available literature data was carried out.

The isotope selectivity of computed tomography (CT) imaging based on nuclear resonance fluorescence (NRF) transmission method using a quasi-monochromatic laser Compton scattering (LCS) gamma-ray beam in the MeV region was demonstrated at the UVSOR-III synchrotron radiation facility for two enriched lead isotope rods (206Pb and 208Pb) implanted in an aluminium cylinder. Since these two rods show the same gamma-rays attenuation in atomic processes, it is impossible to differentiate between them using a standard Gamma-CT technique based on atomic attenuation of gamma rays. The LCS gamma-ray beam had a maximum energy of 5.528 MeV and an intensity of approximately 5.5 photons/s/eV at the resonance energy (JΠ = 1-at 5.512 MeV in 208Pb). A lead collimator with a hole diameter of 1 mm was used to define the size of the LCS gamma-ray beam at the CT target. The CT image of the 208Pb rod was selectively obtained with a 2-mm pixel size resolution, which was determined by the horizontal step size of the CT stage.

This study investigates the distribution, transfer, and potential ecological risks of naturally occurring radioactive materials, including radon-222 (²²²Rn), radium-226 (²²⁶Ra), thorium-232 (²³²Th), and potassium-40 (⁴⁰K), in the aquatic ecosystem of Nasser Lake, Egypt. As Egypt’s largest freshwater reservoir and a critical source of drinking water and fish, Nasser Lake plays a key role in environmental stability and public health. A total of 40 environmental samples—sediment, water, aquatic plants, and fish—were collected from 10 strategically selected sites around the lake. Gamma spectroscopy using sodium iodide activated with thallium [NaI(Tl)] detectors and AlphaGUARD radon monitoring systems was employed to measure radionuclide activity concentrations. Spatial distribution patterns were analyzed using Geographic Information System (GIS) techniques to identify zones of elevated radioactivity. The highest concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were recorded in sediment samples near the High Dam, reaching 10.99 ± 0.42 Bq kg⁻¹, 23.94 ± 1.91 Bq kg⁻¹, and 277.38 ± 23.86 Bq kg⁻¹, respectively. A strong positive correlation (Pearson’s r = 0.913) was observed between ²²⁶Ra and ²²²Rn exhalation rates, confirming that sediment accumulation significantly contributes to local radiological emissions. Bioaccumulation studies showed progressive uptake of radionuclides along the aquatic food chain, with fish exhibiting a bioaccumulation factor (BAF) of 0.74 for ²²⁶Ra. Estimated annual radiation doses from fish consumption reached up to 6.435 microsieverts per year (µSv y⁻¹), remaining below international reference levels established by the World Health Organization (WHO). However, the combination of localized contamination near the High Dam and high fish consumption in nearby communities may present long-term radiological exposure risks. These findings highlight the importance of continuous monitoring of radioactive contaminants in sediment, water, and aquatic organisms in Nasser Lake. The study also provides a transferable framework for assessing the behavior of technologically enhanced naturally occurring radioactive materials (TENORM) in freshwater environments and supports the goals of the United Nations Sustainable Development Goals (SDGs) for clean water and good health.

This study provides a comprehensive evaluation of naturally occurring radionuclides—radium-226 (²²⁶Ra), thorium-232 (²³²Th), and potassium-40 (⁴⁰K)—in groundwater systems across the Nile Valley regions of Upper Egypt, based on the analysis of 85 groundwater wells. Measured mean activity concentrations were 0.74 ± 0.3 Bq/L for ²²⁶Ra, 0.24 ± 0.1 Bq/L for ²³²Th, and 13 ± 4 Bq/L for ⁴⁰K, with ²²⁶Ra displaying low correlations with salinity indicators including chloride (Cl⁻), sodium (Na⁺), electrical conductivity (EC), and total dissolved solids (TDS). Notably, approximately 30% of sampled wells exceeded the World Health Organization (WHO) guidance level of 1 Bq/L for ²²⁶Ra, primarily in central and eastern zones influenced by elevated salinity and evaporite dissolution processes. Geospatial mapping combined with multivariate statistical analysis identified four principal components accounting for over 85% of total data variability, demonstrating that depth-dependent processes, including prolonged water–rock interaction and redox evolution, are the primary controls on ²²⁶Ra mobilization, with salinity-driven ion exchange as a secondary factor. Minor anthropogenic influences, potentially linked to agricultural activities in shallow aquifers, were also detected. Radiological risk assessment confirmed that calculated annual effective doses remain well within international safety limits (<1 mSv/year), although infants and children demonstrated relatively higher exposure levels due to increased water intake per unit body weight. Lifetime cancer risk estimates via ingestion pathways yielded values below 1 × 10⁻⁴, aligning with global health organization benchmarks and reinforcing the general safety of groundwater use in the region. The study highlights potential risks posed by saline groundwater to ancient monuments and archaeological sites, as the cycles of salt forming and breaking down might speed up damage to buildings made of limestone and sandstone. These findings establish a robust scientific foundation for future groundwater quality management and cultural heritage conservation efforts in the Nile Valley region of southern Egypt.