Concentrations Of Natural Radionuclides Research Articles

Трансформация радиоактивного загрязнения донных отложений Калининградского залива в период 2011–2023 гг.

The article presents the data of radioecological research of the bottom sediments in the Russian zone of the Vistula Lagoon in 2011–2023. According to research, the specific activity of 137Cs in the bottom sediments of the Lagoon was in the range of 3,9–165 Bq/m3. 137Cs is the main technogenic radionuclides that makes the greatest contribution to the pollution of the Lagoon. Contamination of the bottom sediments with 137Cs is determined by the redistribution of mainly post-Chernobyl fallout. The 137Cs accumulation was recorded in the northern deep-water part of the Primorskaya Bay. According to observations, the effective half-life of 137Cs activity in the sediments of the Lagoon is 10,4–42 years. The content of natural radionuclides is: 226Ra – from 9,0 to 35,3; 232Th – from 3,8 to 43,2; 40K from 227 to 715 Bq/kg. The NRN specific activity in the sediments of the Lagoon did not exceed 153 Bq/kg, which was significantly lower than the established safe level (370 Bq/kg), allowing their handling without restrictions. The correlations between the content of 40K, 226Ra, 232Th in the bottom sediments of the Lagoon were established with the type of sediment

Characterization of a typical urban soil in terms of natural radionuclide content. The case study of a university campus

A first comprehensive survey was carried out in a university campus in Italy in order to investigate in terms of natural elements an area where medium-high values of natural radiation are expected because of its peculiar geological features. The content of terrestrial radionuclides in 20 topsoil samples from the campus was determined with the aim to provide an important database of the soil characteristics.226Ra, 232Th, and 40K concentrations were analysed by High Purity Germanium (HPGe) gamma-ray spectrometer in order to determine the background levels of natural radionuclides characteristics of the original area. The mean concentrations of radionuclides in the investigated soil samples ranged from 58.95 ± 4.20 to 158.05 ± 19.95 Bq kg−1 for 226Ra, from 72.28 ± 7.61 to 146.00 ± 22.27 Bq kg−1 for 232Th and, for 40K, from 550.76 ± 33.24 to 1367.50 ± 18.73 Bq kg−1. The radiological hazard indices, including radium equivalent activity, external hazard index, annual effective dose, absorbed dose rate, lifetime excess cancer risk, were also evaluated and compared with global averages, revealing values above the worldwide ones. Finally, a spatial modelling methodology of the site-specific radionuclides levels as graphical tool for the monitoring of the potential land redevelopment of urban soils was proposed.

Natural radionuclide profiles and radiological risks in soils and rocks of the Koytash-Ugam Range, Uzbekistan.

This investigation quantifies the activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) in the soils and certain rocks of the Koytash-Ugam Range, Uzbekistan, and assesses their radiological risks. Gamma-spectrometric analysis of soil and rock samples revealed activity concentrations ranging from 456.2 ± 56.0 to 813.9 ± 76.0Bqkg-1 for 40K, 18.2 ± 6.3 to 70.0 ± 12.0Bqkg-1 for 226Ra, and 30.1 ± 2.9 to 57.9 ± 10Bqkg-1 for 232Th. This data indicates a heterogeneous distribution of radionuclides, informing radiation safety and health risk assessments on a global scale. The calculation of radiological hazard indices, including the alpha-index (ranging from 0.09 to 0.35), gamma-index (ranging from 0.40 to 0.73), and both internal (ranging from 0.40 to 0.54) and external (ranging from 0.36 to 0.54) hazard indices, was undertaken to ascertain potential health risks. The radium equivalent activity ranged from 108.4 to 199.3Bqkg-1, and the absorbed dose rates were 51.0-93.3 nGy h-1 indoors and 96.6-178.2 nGy h-1 outdoors. These metrics underlie the estimated annual effective dose of 536.5-988.5 × 10-3mSv y-1, highlighting the variability in radiation exposure. Additionally, the potential lifetime cancer risk was projected at 1770.4 to 3262.0 per million, with an annual gonadal dose equivalent of 361.9 to 655.5 μSv y-1, reflecting natural background radiation influence. The results underscore the importance of safe material use in construction and the necessity for routine natural radioactivity monitoring. Radon flux density (RFD) values within acceptable construction limits (26-176mBqm-2s-1) suggest the area's suitability for development, considering recommended safety guidelines. This study not only aids local environmental and public health frameworks but also enriches the international knowledge base, facilitating comparative studies for the advancement of global radiation protection standards. Through a detailed examination of radionuclide distribution in an under-researched area, our research highlights the critical need for integrated international approaches to natural radiological hazard assessment.

Radioecological perspective: The concentration of natural radionuclides around the coast of PLTU Labuan

The utilization of coal in Power Plants (PLTUs) can lead to the generation of fly ash waste, which may contain natural radionuclides that can potentially contaminate the surrounding environment. Despite Labuan PLTU's land-coastal location, marine environment monitoring remains minimal. A recent study conducted sediment and seawater sampling, revealing varying levels of natural radionuclides 226Ra, 232Th, and 40K ranging from 3.4 to 27.5 Bq kg−1, 3.9 to 34.9 Bq kg−1, and 64.0 to 275.0 Bq kg−1 in sediments, respectively. Meanwhile, the activity concentration of natural radionuclides 226Ra and 232Th in seawater ranges from 0.5 to 1.1 Bq L−1 to 0.7–1.5 Bq L−1, respectively. These findings provide baseline data for marine radiation levels around PLTU Labuan. Additionally, risk assessments were conducted, indicating Raeq, Hin, and Hex ranges of 13.80–91.00 Bq kg−1, 0.04–0.25, and 0.05–0.31, respectively. The study concludes that Labuan's radiation levels are within safe limits for exposure.

Determination of potentially toxic metals and natural radionuclides in airborne pollens produced different urban environments in Turkey and health risk assessment

ABSTRACT Air pollutants are associated with potentially toxic metals (PTMs) and natural and/or artificial radionuclides, which can pose a major threat to human and environmental health. Pollens can be utilized as a bioindicator to determine the level of air pollution in urban areas. In this study, the concentrations of PTMs and natural radionuclides in 35 airborne pollen samples of 22 species belonging to Pinaceae, Cupressaceae, Araucariaceae, Betulaceae, Salicaceae, and Oleaceae families grown in different urban areas in Turkey were determined using an energy-dispersive X-ray fluorescence spectrometry. For the first time, non-carcinogenic and radiologic health risk assessments for adults were done, estimating hazard index (HI) and annual effective dose (AED), respectively. The concentrations of Fe, Mn, Zn, Ti, Sr, Cu, Ni, Co, Cr, V and Pb analyzed in airborne pollen samples varied from 52.1 to 3078.0, 26.1 to 159.6, 15.6 to 199.7, 9.1 to 282.2, 1.0 to 128.4, 5.0 to 40.1, 5.4 to 23.6, <LD to 11.3, 1.6 to 26.6, <LD to 11.1 and <LD to 5.7 mg/kg, respectively. The average concentrations of K (2%), Th (1.3 mg/kg) and U (1.0 mg/kg) were converted into the activity concentrations (in Bq/kg) of 40K (595.8), 232Th (5.2) and 238U (11.8), respectively. All HI and AED values revealed a very low non-carcinogenic and radiological health risk due to exposure to all PTMs and radionuclides in the pollen samples studied.

Background radioactivity level estimation and passive shield optimization using adjoint Monte Carlo method

The current study proposes a procedure to estimate the activity concentration of natural radionuclides and to optimize passive shielding solutions for HPGe detectors using adjoint Monte Carlo (MC) simulation technique of Geant4 for the first time. The background spectrum is acquired for 1.56 × 106 s using an HPGe detector model (GC3020), set inside a shielding solution, during 2021–2022 to estimate the activity concentration of natural radionuclides inside the shielding. While, a background spectrum for 65,000 s is acquired with shielding removed to estimate the concentration of natural radionuclides in the building materials of the laboratory. The detector design used in the simulations is validated by comparing computed and measured Full Energy Peak Efficiency (FEPE) for point sources 241Am, 152Eu, 137Cs, 133Ba, and 60Co. Adjoint MC simulations are used to compute the activity concentration of natural radionuclides assuming an isotropic distribution. The activity concentration of 40K, 226Ra and 232Th in the building material is found to be 524 ± 140, 83 ± 20 and 65 ± 18 Bqkg−1, respectively. The computed values are found in good agreement with the published data. The natural radioactivity levels of 40K, 226Ra and 232Th measured in lead shielding are 155.7 ± 0.1 mBqkg−1, 24 ± 13 mBqkg−1 and 33 ± 17 mBqkg−1 respectively. The radiological risks arising due to natural radioactivity is assessed by calculating radium equivalent activity (Raeq), indoor radiation hazard index (Hin) and annual effective dose equivalent. All the radiological parameters are found below their permissible limits and building materials may be considered radiologically safe. The optimal lead shield thickness for the detector is determined to be 12 cm, resulting in reduction of background signal by two orders of magnitude compared to an unshielded detector. The adjoint MC simulations in Geant4 are 103-104 times more rapid as compared to normal simulations for shield optimization of HPGe detectors and therefore, are identified as viable computing solution to calculate the activity of the background radiation.

Assessment of the mobility of potentially toxic trace elements (PTEs) and radionuclides released in soils stabilized with mixtures of bentonite-lime-phosphogypsum.

Phosphogypsum (PG) is a solid by-product of the phosphate industry, rich in contaminants and produced in large quantities. Raw materials and stabilized specimens, consisting of bentonite-lime-PG mixtures, were characterized by mineralogical, microstructural, chemical, alpha-particle, and gamma-ray spectrometry analysis before hydration and after hardening. Compressive strength and leaching tests were performed on hardened specimens. The physicochemical parameters and chemical composition of leachates from raw materials and hardened specimens were determined. PG contains high concentrations of natural radionuclides, specially from U series. Uranium-238 activities are double in PG than the worldwide average for soil values. The mobility of PTEs from PG is Cd (2.43%), Zn (2.36%), Ni (2.07%), Cu (1.04%), Pb (0.25%), and As (0.21%). Cadmium is the cation most easily released by PG in water with a concentration 0.0316mgkg-1. When PG is added to bentonite-lime mixture, cadmium is no longer released. The radionuclide 238,234U and 210Po predominates in the leachates of PG. However, the activity of 210Po becomes negligible in the leachates of bentonite-lime-PG mixtures. The addition of PG to bentonite-lime mixtures facilitates the trapping of trace elements (PTEs) and radionuclides, providing potential applications for PG as road embankments and fill coatings.

Estimation of natural radioactivity and radiological hazards in aggregate (stone dust) used as building materials in South Africa

ABSTRACT In this study, the radioactivity concentrations of natural radionuclides (Uranium-238, Thorium-232, and Potassiumi-40) in aggregate/stone dust samples used for building construction purposes have been measured with thallium-doped sodium iodide (NaI(TI)) detector. The samples’ associated radiological hazard risks were calculated using standard radiological expressions. The mean values of Uranium-238, Thorium-232, and Potassiumi-40 activity concentrations in the studied Quarries’ samples were above the World mean values of 35, 30, and 400 Bq.kg−1 for radioactivity concentrations in building materials. The lowest and highest values of all the estimated radiological hazard indices were recorded in samples Afrisam C 5 and Afrimat 3.

Radiation survey of the territory of Teriberka village and Kildin Island of Murmansk Region

The Arctic zone is a strategically important territory of the Russian Federation from the point of view of socio-economic, scientific, and technological components, as well as in terms of planning the development of a system for ensuring national defense, state, and public security. Intensive exploration and development of Arctic territories, combined with a rapidly changing environment due to global climate change, carries a few risks for the environment. This determines the need to assess potential environmental damage and determine the significance of factors of potential negative impact on unique Arctic ecosystems now and in the future. The article presents current data from a radiation survey of the coastal zone of residential areas close to the site of the sinking of the nuclear submarine ‘K-159’ – Teriberka village and Kildin Island, Murmansk region, as well as the sea area to assess the primary levels of man-made and natural radionuclides before starting work on the potential lifting of the submerged object. This work was carried out as part of the implementation of the State Program of the Russian Federation ‘Health Development’ (approved by Decree of the Government of the Russian Federation dated December 26, 2017, No. 1640). The results of measuring the ambient dose equivalent rate of gamma radiation in open areas and determining the content of man-made and natural radionuclides in samples of environmental media (soil, aquatic vegetation, marine aquatic organisms) and food products of local origin and production (mushrooms, berries, fish, milk). The research results showed that the state of the study area is generally stable in terms of the radiation factor, the content of radionuclides is at the background level. As part of this work, electronic database modules have been developed based on the results of radiation monitoring in Teriberka village and on Kildin Island. Certificate No. 2022621890 was received on registration of a database with the results of the radiation situation of the above-mentioned territories.

Radiometric and petrographic characterization of El-Yatima granite: Evaluating radiological risks and mineralogical features

The current investigation aims to assess the potential of El-Yatima granitic pluton as a decorative stone by examining its natural radioactivity and mineralogical elements. Specifically, the study aims to determine the concentrations of radionuclides 40K, 232Th, and 226Ra, perform petrographic analyses, and evaluate the associated radiological risks to determine the safety and usability of the granite in construction and decoration, as well as to assess the potential of these granitic rocks as a safe and effective decorative stone for various applications. It has a 12 km2 surface area of 812 m above sea level. It is situated in the Eastern Central Desert. Its hypidiomorphic texture, medium-to-coarse grain size, and predominant composition of K-feldspars, quartz, and plagioclase are observed, along with minute amounts of muscovite and biotite. By employing NaI (Tl) gamma-ray spectroscopy, the natural radionuclide concentrations of 40K, 232Th, and 226Ra in El-Yatima granitic rocks were ascertained. Additionally, radiological concerns were identified for the materials that were examined. The average concentrations of radionuclides 40K, 232Th, and 226Ra are 178 Bqkg−1, 44 Bqkg−1, and 41 Bqkg−1, respectively. The following are the computed values: 117 Bqkg−1, 0.43, 0.32, 53 nGyh−1, average radium equivalent (Raeq), hazard indices (Hin and Hex) and dose rate (D), respectively. When compared to levels typically indicated, it was discovered that its values were within the worldwide standard. The study's findings could be a starting point for radiometric data for upcoming surveillance and epidemiological research.

The surface of small glaciers as radioactive hotspots: Concentration of radioisotopes during predicted intensive melting in the Alps

Glaciers are considered secondary sources of pollutants, including radioisotopes such as Cesium or Plutonium, with heightened concentrations compared to other ecosystems. The predicted melting of glaciers poses a substantial risk of releasing stored radioisotopes, yet understanding the glacier-specific factors influencing their concentration remains limited. This study investigates the relationship between glacier altitude, surface area, organic matter content in dark supraglacial sediment (cryoconite), precipitation, and activity concentrations of natural (210Pb) and anthropogenic radionuclides (137Cs and 241Am) across 19 Alpine glaciers. Results indicate that radioisotope concentrations depend on organic matter content in the cryoconite, highlighting the role of biotic-abiotic interactions in pollutant accumulation on glaciers. Moreover, 210Pb activity concentration decreases with glacier altitude, likely due to atmospheric variations in 222Rn. Water precipitation events, such as during peaks in 137Cs deposition and after the Chernobyl Nuclear Power Plant disaster, do not impact current activity concentrations. Importantly, radioisotope concentrations in cryoconite are higher on smaller glaciers. This directly supports the hypothesis that the cryoconite retains a significant share of radioisotopes stored in the ice during intensive melting. Since many small glaciers in the Alps are predicted to disappear within the next 50 years, we anticipate release of radioisotopes to mountain ecosystems might be higher than previously forecasted.

Statistical assessment of natural radioactivity, radon activity, and associated radiological exposure due to artisanal mining in Atiwa West district of the Eastern region, Ghana

The activity concentration of natural radionuclides, radon activity concentration, mass and area exhalation rates have been studied in soils from gold mining communities in Atiwa West district. The natural radionuclides were determined by gamma ray spectrometry method while radon concentrations were measured using CR-39 detectors. The mean activity concentrations were found to be 26.9 ± 1.7 Bq/kg, 57.5 ± 3.6 Bq/kg, 237.5 ± 17.6 Bq/kg and 560.0 ± 54 Bq/m3 for Ra-226, Th-232, K-40 and Rn-222 respectively. The evaluated mass exhalation rates ranged from 2.8 ± 0.3 to 6.5 ± 0.7 × 10−5 Bq/kg/h while the area exhalation rates were from 0.8 ± 0.09 to 2.0 ± 0.21 × 10−3 Bq/m2/h. Some mining and farming areas recorded high exhalation rates indicating that the use of soils as building materials from such areas could pose a level of radiation hazard to the population. The evaluated radiological risks were below reference levels. A good linear correlation was observed between Ra-226 and Rn-222 activity concentrations and in the investigated soils. The Pearson correlation coefficient, cluster analysis and principal component analysis were used to study the relationship between the determined parameters of the study.

Measurement of Natural Radioactivity in Fly Ash from a Lignite-Fired Thermal Power Plant and Radiological Risk Assessment Using RESRAD Code

In this study, the activity concentrations of natural primordial radionuclides in fly ash (FA) samples collected from the landfill area of Afşin-Elbistan A lignite-fired thermal power plant (AE-A LFTPP) located in Kahramanmaraş province of Türkiye were measured using a gamma-ray spectrometer. Also, the radiological risk was assessed using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of 226Ra, 232Th and 40K in FA samples varied from 291 ± 10 to 853 ± 25 Bq/kg, 23 ± 1 to 125 ± 4 Bq/kg and 112 ± 10 to 315 ± 18 Bq/kg, respectively. The predicted maximum total annual effective dose rate due to the natural radionuclides and their progenies is 4.7, 4.4, and 4.0 mSv/y at t = 1000 y for 0.5-m, 1.25-m, and 2.0-m cover scenarios, respectively. While the predicted maximum total cancer risk is 4.56 × 10−3 (3.95 × 10−3 for 226Ra, 5.18 × 10−4 for 232Th and 6.14 × 10−15 for 40K), 4.00 × 10−3(3.80 × 10−3 for 226Ra, 1.90 × 10−4 for 232Th and 7.69 × 10−15 for 40K) and 3.71 × 10−3 (3.71 × 10−3 for 226Ra, 1.820 × 10−8 for 232Th and 7.66 × 10−15 for 40K) at t = 1000 y for 0.5-m, 1.25-m and 2.0-m cover scenario, respectively. Results also revealed that the total doses and cancer risks are less in thicker cover scenarios throughout the 1000 y time span and that 226Ra is the major contributor to the risk in all the scenarios owing to its higher activity concentration than 232Th and 40K.

Naturally occurring radioactive material (NORM) in Saudi Arabia: A Review

Saudi Arabia, the world's largest crude oil exporter, also possesses rich deposits of natural resources like phosphate, bauxite, copper, and various minerals. Extracting and processing these resources can concentrate naturally occurring radionuclides in the resulting products, byproducts, residues, and wastes. This can sometimes elevate their activity concentrations above original levels, potentially increasing exposure risks for workers and the public, and contaminating the environment.This review provided a comprehensive overview of naturally occurring radioactive materials (NORM) across various industries in Saudi Arabia. It outlines the regulatory framework established by the country's authority for NORM management. By reviewing current literature, the article presents activity concentrations of key radionuclides of interest - 40K and those from the 238U and 232Th decay series-within different industries. The review highlights the need for further research to assess the impact of industrial processes on the activity concentrations of natural radionuclides. It concludes by calling for additional studies to address the significant knowledge gap on NORM in specific industries, particularly phosphate, bauxite, water treatment plant and oil and gas, which have the potential to generate radioactive waste. The importance of characterizing industries involving NORM is emphasized for evaluating radiological impact and implementing appropriate safety measures.

Physico-chemical, technological and radiological characteristics of kaolinized granite from northwestern Serbia

In the ceramic industry, the quality of the final ceramic tile as well as the possibility of its use depends on the quality and characteristics of the starting raw materials. One of the potential raw materials that can be used in the production of ceramic tiles is kaolinized granite, and it is necessary to examine its characteristics. In this research, the kaolinized granite of the Jadar block, northwestern Serbia, from the Beli Majdan surface mine, Jadranska Lešnica, was examined. Chemical analysis, X-ray diffraction analysis (XRD), and differential thermal analysis (DTA) were carried out. Ignition tests of the prepared composites were also conducted at three selected temperatures (1000, 1100, and 1250 °C), where total linear shrinkage and water absorption were determined. The activity concentrations of natural radionuclides and the artificial radionuclide 137Cs were determined using the gamma spectrometry method, and then the radiation risk for the external exposure of workers when working with this raw material was assessed. For the samples with the highest content of 226Ra, radon exhalation measurements were performed with the RAD7 device, and the values of the radon emanation coefficient were determined, as well as the values of alpha dose equivalents, which quantified the potential internal exposure of workers. The results of the chemical analysis showed that the content of Al2O3 in the examined composites ranged from 19.11 to 21.00%, and the content of Fe2O3 from 1.53 to 1.72%. Additionally, the K2O content in the tested composites ranges from 4.01 to 5.46%, which indicates the presence of K-feldspar and muscovite, and the Na2O content from 1.82 to 2.61%. Based on XRD analysis, it was established that the mineral composition of kaolinized granite includes quartz, feldspar, mica, calcite/dolomite, and kaolinite minerals. DTA analysis indicates the occurrence of minor endothermic processes at 488.05 °C and 558.12 °C, as well as an exothermic process at 980.8 °C. The color of the ignition is brick red to dark brown red. A trend of increasing linear shrinkage and decreasing water absorption with increasing ignition temperature was observed with the normal appearance of the samples. The average activity concentration of natural radionuclides are around and below the average values for building materials, expect for 40K. The values for 137Cs are below the values measured in soil. Annual effective doses estimated for external exposure are below 1 mSv y−1, which indicates that there is no increased radiation risk when working with this raw material. The values of the radon mass exhalation rate are in the range of 61–113 mBq kg−1 h−1, and the values of the radon emanation coefficient are 6.3–8.4%. The average value of the alpha dose equivalent is 1mSvy−1, which indicates a potential exposure to radon below 100 Bq m−3. Based on the obtained results, it can be concluded that kaolinized granite is a high-quality and radiologically safe raw material for making ceramic composites in the production of ceramic tiles. It has all the necessary characteristics to partially or completely replace feldspar in ceramic composites.

Natural Radionuclides Concentrations and Associated Radiation Hazard of Some Building Rocks Used in Taiz City, Yemen

Building materials comprise a diverse range of natural rocks that contain varying mineral components including radionuclides. Gamma spectrometry-based high-purity Germanium detectors were utilized to measure the activity concentrations of natural radionuclides: Radium-226 (226Ra), Thorium-232 (232Th), and Potassium-40 (40K) in various building rock samples found within and surrounding Taiz city. The activity concentrations of 226Ra, 232Th, and 40K vary from 27.79 ± 0.77 to 234.49 ± 3.13 Bq.kg-1, 25.82 ± 0.40 to 415.31 ± 2.47 Bq.kg-1, and 457.91±2.61 to 1139.56 ± 5.43 Bq.kg-1 with overall average value of 71.55 Bq.kg-1, 93.87 Bq.kg-1, 966.88 Bq.kg-1 respectively, these values were higher than the permissible thresholds. Furthermore, several radiation hazard indices were estimated including the radium equivalent (Raeq), the external hazard index (Hex), the internal hazard index (Hin), the gamma level index (Iɤ), the dose rate(Dɤ), the annual effective dose equivalent (AEDE), the excess lifetime cancer risk (ELCR), and the annual gonadal dose equivalent (AGDE). The findings illustrated that Basalt rocks have the minimum values of radiation hazard indices while the Himatite rocks have the maximum values of radiation hazard. The average values of radiation risks for most of building rocks fall below the recommended limits for safety. Based on the Radiation hazard indices of building rock samples, it can be concluded that with the exception of hematite rocks, all the examined rocks are considered safe for use in construction materials and pose non-significant radiation risks. The awareness about natural radioactivity levels of building rocks is critical for planning and performing strategies in radiation safety of buildings.

Gross alpha/beta and radionuclide activity concentrations in soil, plant and some fruits around the Tehran Research Reactor

Human activities usually have some contamination as effluents from chemical industries and radionuclides from nuclear reactors. For assessing the probable radioactive contamination in vicinity of Tehran Research Reactor, The gross alpha and beta radioactivity concentrations in soil, pine and cedar leaves and some selected fruits (fig, apple, berry and pomegranate) were investigated using an alpha/beta spectrometer during 2021–2022. Also, the concentrations of artificial and natural radionuclides in samples were investigated by the method of gamma spectroscopy. The gross alpha activity concentrations in soil, pine and cedar leaves and some selected fruits samples are from 0.05 to 0.35 Bq/gr and 0.07–0.31 Bq/gr and 0.04–0.18 Bq/gr, respectively. The gross beta activity concentrations in soil, pine and cedar leaves and some selected fruit samples are from 0.73 to 4.25 Bq/gr and 0.21–3.97 Bq/gr and 1.01–2.71 Bq/gr, respectively. Average activities concentration of natural radionuclide 232Th, 238U and 40K in soil, pine and cedar leaves and some selected fruits are 31.89–16.23–582.73 Bq/kg and 1.84–0.99–84.60 Bq/kg and 1.98–1.09–72.08 Bq/kg respectively. From artificial radionuclides, just 137Cs is recognized in soil sample and the range of 137Cs concentration in surface soils was observed to vary in the range 0.85–2.21 (Bq/kg). The result showed that the Tehran Research Reactor activities not have increased the environmental radioactivity and radiation level in the area.

Estimation of annual effective radiation dose and cancer risk due to tea consumption

The current study aims to assess the radioactive health risks and their levels due to tea consumption. Fresh tea leaves were plucked from different locations in the Gumero tea farmland in Ilubabour zone, Ethiopia. High-resolution gamma-ray spectroscopy was used to measure the activity concentrations of artificial and natural radionuclides (e.g., 40K, 232Th, and 238U) in the samples. Radiological indicators such as committed dose rate (DR) and excess lifetime cancer risk, LCR (i.e., the cancer death risk due to lifetime exposure to carcinogens, ignoring the contribution of natural background risk) were evaluated to ascertain the radioactive risk to humans in the tea samples. DR and LCR, two radiological markers, were assessed to determine the radioactive risk to humans in the tea samples. The finding shows that the radiological hazards assessment of 238U and 232Th revealed that the Gumero tea leaves have natural radioactivity levels within the internationally recommended limit, while that of 40K was higher than the limit. Comparing the current study with other studies, it was found that the yearly effective doses and nuclide radioactivity concentrations in tea leaves were similar.

Calibration of buried NaI(Tl) scintillator detectors for natural radionuclide measurement based on Monte Carlo modelling

Measurements of naturally occurring concentrations of 40K, and of the decay series of 238U and 232Th, are of interest in the earth sciences in general, and in particular, scintillator-based gamma spectrometers can be used for the low cost determination of burial dose rates in natural geological samples. We are currently developing a robust, portable, wireless detector specifically intended for field measurement of natural radionuclide concentrations and hence, the calculation of dose rates. One of the challenges in developing and applying such an instrument is reliable calibration. Most calibrations of field instruments depend on access to non-finite matrices of known K, U, Th activity concentrations, in either a 4π or 2π geometry; these are only available at a few facilities around the world. Here we investigate an alternative approach, based on the measurement of small samples containing well-known activity concentrations of only K or U or Th, and Monte-Carlo radiation transport modelling to convert the observed spectra into those expected from specific activity concentrations in a non-finite 4π geometry. We first validate our modelling procedure by simulating these observed spectra. The non-finite matrix calibration spectra are then predicted, and least-squares fitted to the spectrum observed at the centre of a 1 m3 of granite chips; the resulting predicted U, Th and K activity concentrations are compared with independently known values.

Seasonal Fluctuations in the Concentration of Natural Radionuclides in Groundwater of Al Dhahirah Governorate, Oman

Seasonal Fluctuations in the Concentration of Natural Radionuclides in Groundwater of Al Dhahirah Governorate, Oman