Natural Radionuclides Research Articles

Radioactivity in food crops from the family farms in Croatia with ingestion dose assessment

The results of radioactivity measurements and transfer factor calculations of natural and anthropogenic radionuclides in various food crops from family farms in Croatia are presented. Measurements were performed using gamma spectrometry for 40K, 137Cs, 210Pb, 226,228Ra and 228Th, liquid scintillation counting for 90Sr and alpha spectrometry for 210Po. The activity concentrations were used to determine the annual ingestion dose for one – year – olds, ten – year – olds and adults, calculated to be 0.533, 0.666 and 0.348 mSv, respectively. 70% of the dose comes from 228Ra and 40K. Other significant contributors are 226Ra, 210Pb and 210Po. Contribution per foodstuff groups for one – year – olds as the most sensitive group in descending order is: cereals > leafy vegetables > fruits > non–leafy vegetables > tubers > roots vegetables > herbs ≫ nuts. All results are in line with worldwide studies and below the limit of 1 mSv/y.

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.

A new certified reference material IAEA-465 for radionuclides in Baltic Sea sediment

Certified reference material (CRM) for natural (40K,210Pb,210Po,226Ra,228Ra,228Th,230Th,232Th,234U,235U, and238U) and anthropogenic (137Cs,239+240Pu, and241Am) radionuclides in marine sediment from the Baltic Sea (IAEA-465) has been developed. Information values are given for 238Pu,239Pu and240Pu. Altogether 27 laboratories participated in this exercise. Radiometric (alpha-spectrometry, gamma-spectrometry and beta counting, as well as mass spectrometry (ICP-MS and AMS) techniques were applied in measurements. The CRM is intended to be used for Quality Assurance/Quality Control of radionuclide analyses, for the development and validation of analytical methods, for the development of reference methods and for training purposes.

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.

Correction to: A study on natural and anthropogenic radionuclides in farmed fish and shellfish in Singapore

Correction to: A study on natural and anthropogenic radionuclides in farmed fish and shellfish in Singapore

Assessment of radiation dose due to 238U, 226Ra, 222Rn and 210Po in groundwater of Kodagu district, India.

Natural radionuclides are universally spread and can be found in varying levels in rock, soil and water depending on the geology. A potential health threat may be caused by them to humans on consumption of water, food and inhalation of air due to the presence of radionuclides. In the present study, an attempt has been made to study the distribution of 238U, 226Ra, 222Rn and 210Po in groundwater samples of Kodagu district, India. The activity concentrations of 238U, 226Ra, 222Rn and 210Po were found to vary from 0.44 to 8.81μgL-1, 0.71 to 7.66 mBqL-1, 1.54 to 9.61BqL-1 and 0.47 to 4.35 mBqL-1, respectively. The associated dose due to radiation was assessed and was observed to be below the recommended standards. The total effective dose to the population was calculated and was found to be less than the recommended WHO standard of 100mSv.

The Radioecological Peculiarities of Soil Cover in Mountainous Areas (Kyrgyzstan)

The article presents the results of a radiological study of mountain soils depending on the height above sea level (740 - 760; 1600-1700 and 2000-2500 m above sea level) on the territory of the Kyrgyz Republic. Mountainous areas are characterized by denudation-erosion processes and humus; total nitrogen, gross phosphorus and potassium in the soil cover in mountainous zones are not uniform; in general, the studied zones are at the level of a natural area with small deviations, this is due to both natural and man-made processes. The content of natural radionuclides in the studied soil samples of mountain dark chestnut soils (tailing ponds and the adjacent territory) is several times higher than the average Clarke values, where a sharp decrease in the content of radionuclides is observed in the lower 20-60 cm layers, compared to mountain meadow-steppe subalpine soils. Radioecological analyzes in the city of Bishkek showed that, in general, the exposure dose is at background levels and below established standards. In the Issyk-Kul Biosphere Territory, the calculated annual doses to the population from all routes of exposure to radionuclides in the conditions of the Issyk-Kul region do not exceed the established norm (1 mSv per year). Mothballed storage facilities and dumps are a dangerous potential source of environmental pollution and therefore require constant monitoring.

Natural radiological risk assessment around archaeological sites, El-Dakhla Oasis (EDO), Egypt

The natural radionuclides in ancient El-Qasr village located in the El-Dakhla oasis (EDO), Egypt's Western Desert were measured using gamma-ray spectrometry equipped with a NaI (Tl) detector. The findings indicate that the samples' mean activity concentrations were 18.61 ± 1.02, 16.67 ± 0.9, and 137.67 ± 6.9 Bq kg−1 for 226Ra, 232Th, and 40K, respectively. The values of Raeq, D, AED, Hex, Hin, Iγ, and ELCR for the samples ranged anywhere from 34.1 to 83.9 Bq kg−1, 15.7 to 37 nGy h−1, 19.26 to 45.384 Sv y−1, 0.09 to 0.23, 0.12 to 0.23, 0.25 to 0.59, and 6.74E−05 to 1.59E−04, respectively. These values are significantly lower than the international limit of 370 Bq kg−1 for Raeq, 59 nGy h−1 for D, 70 Sv y−1 for AED, 1 for Hex and Hin, 2 for Iγ, and 29E−03 for ELCR. According to the obtained data, none of the samples seemed to be a significant risk when it came to radiation exposure. Using these data, we will determine the baseline level of radionuclides that occur naturally in the area that is the subject of the inquiry.

Radiological characterization of the tailings of an abandoned copper mine using a neural network and geostatistical analysis through the Co-Kriging method

The radiological characterization of soil contaminated with natural radionuclides enables the classification of the area under investigation, the optimization of laboratory measurements, and informed decision-making on potential site remediation. Neural networks (NN) are emerging as a new candidate for performing these tasks as an alternative to conventional geostatistical tools such as Co-Kriging. This study demonstrates the implementation of a NN for estimating radiological values such as ambient dose equivalent (H*(10)), surface activity and activity concentrations of natural radionuclides present in a waste dump of a Cu mine with a high level of natural radionuclides. The results obtained using a NN were compared with those estimated by Co-Kriging. Both models reproduced field measurements equivalently as a function of spatial coordinates. Similarly, the deviations from the reference concentration values obtained in the output layer of the NN were smaller than the deviations obtained from the multiple regression analysis (MRA), as indicated by the results of the root mean square error. Finally, the method validation showed that the estimation of radiological parameters based on their spatial coordinates faithfully reproduced the affected area. The estimation of the activity concentrations was less accurate for both the NN and MRA; however, both methods gave statistically comparable results for activity concentrations obtained by gamma spectrometry (Student's t-test and Fisher's F-test).

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.

A baseline of natural radionuclides in water and sediment of a pristine coastal ecosystem: The Xcalak and Mahahual coral reef lagoons in the western Caribbean

In ecosystems, natural radionuclides are present in the environment and living organisms. The 238U natural decay chain produces multiple radioactive elements, such as 234U, 226Ra, 210Pb, and 210Po. These radionuclides can be found in air, water, rocks, soil, and other biotic and abiotic components, mainly derived from minerals, such as zircon and apatite. In this study, we determined the activity concentration of radionuclides from the 238U decay chain in the sediment of a coastal ecosystem on the southern Mexican coast in the western Caribbean, an ecosystem minimally affected by industrial activities. Methods included high-resolution gamma-ray spectrometry and alpha-particle spectrometry. Results showed that the sediment samples had an activity concentration range of 18.2–36.6 Bq/kg for 238U, 25.0–41.4 Bq/kg for 234U, 10.1–37.3 Bq/kg for 210Pb, and 29.9–46.0 Bq/kg for 210Po. Water samples ranged between 17.9 and 36.3 mBq/L and 27.9–66.0 mBq/L for 238U and 234U, respectively. The activity concentration of these radionuclides in the sediment and water of this area is compared with that of other coral reefs worldwide, providing a radiometric baseline for comparison purposes.

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.

Revealing the ongoing speleogenetic processes in an underwater cave through the application of natural radionuclides and stable isotopes: case study from the hypogene Buda Thermal Karst

The underwater Molnár János Cave in the hypogene Buda Thermal Karst system (Budapest, Hungary) provides a unique site to study the effects of flowing groundwater and the interplay of fluids of different origin. The aim of the present study is to characterize the groundwater in different parts of the cave with temporal resolution, hence describe the recent speleogenetic processes within the cave. This study uses natural radioisotopes (uranium, radium, and radon) besides stable isotope ratios of oxygen and hydrogen to identify the different fluid components. The results show that the majority of the cave is situated in the flow path of the intermediate flow system, discharging in the Boltív Spring. Thus, the dominant recent speleogenetic processes are connected to this lukewarm groundwater. In contrast to previous views, typical hypogene processes, such as mixing corrosion involving thermal waters, are restricted to a narrower area in the cave, to the contact zone of lukewarm waters and the warmer upper water layer around the largest partially air-filled chamber (Kessler Hall). The warmer water layer is the result of free convection. In the air-filled chambers condensation-corrosion might be active. However, its effect is limited to the largest room (Kessler Hall), as it is open to surface conditions. More active mixing corrosion probably occurs deeper, in the area of the Northeastern Margin Fault, which is indicated by the radon content in the Boltív Spring. Regarding the temporal processes, the main driving force can be linked to the water level fluctuations of the Danube, which regulates the discharge of the regional flow-related thermal water upwelling, thus affecting the mixing ratio of the lukewarm waters transported by the intermediate flow systems and the thermal waters, representing the regional flow path, including basinal components.

Radiation Doses and Risk Assessment Due to Water Intake at Oyo Town, Southwestern Nigeria

From the long standing nature of water usage, water has been has had a significant impact to all great development. Potable water has been recognized as the water intended for human consumption for the purpose of research and other human activities. Therefore, the World Health Organization (WHO) classified 230Th, 226Ra, 210Pb, 210Po, 232Th, 228Ra, 40 K and 228Th as naturally occurring radionuclide contaminants in water and a possible threat to human existence. This work evaluated the activity concentration of natural radionuclide in ground water, examine radiation doses and the threat due to water intake from Oyo town using a 5 cm × 5 cm solid NaI(Tl) gamma-ray spectrometric manufactured by ORTEC and coupled to a Digital-based multi-channel analyzer (MCA). From the results, 92.5 per percent of 40K, 87.5 per cent of 226Ra and 95 of 232Th was greater than the IAEA safe limit of 1.00 Bql−1limit. The average value of an annual effective dose for adults was 0.17±0.06 mSvy−1 and 0.43±0.17 mSvy−1 for children. Cancer risk assessment was obtained to 2.98 x 10−3 compared to ICRP recommended value of 8.4 × 10−3. Health risk implication resulting from consumption of water from the study area poses no health concern, no artificial radionuclide was detected and the chance of cancer occurrence resulting from drinking water from the study area is stochastic. It is recommended that caution should be taken on the fertilizer application on the farm land. Further research is recommended on the radioactivity measure of the soil and food crops grown in the study area.

Оценка пространственно-временных изменений показателей радиоэкологического состояния почв зоны наблюдения Ростовской АЭС

The paper presents the results of a study of long-term (from 2003 to 2021) measurements of the specific activity of natural (226Ra, 232Th, 40K) radionuclides and artificial 137Cs in surface soil samples and soil profiles, including the dependence of the specific activity of radionuclides on some soil properties (content organic matter, pH level) in the observation zone of the Rostov NPP. In accordance with the requirements of radioecological monitoring, the study of the state of terrestrial ecosystems was carried out considering landscape-geochemical and climatic conditions in control plots with Haplic Kastanozems, Gleyic Kastanozems, Endosalic Kastanozems and Umbric Fluvisols soils laid out in the study region in 1999–2000 as part of pre-start monitoring of the Rostov NPP. It has been shown that there is a decrease in the specific activity of 226Ra in all studied soil types. A regular redistribution along the profile of artificial 137Cs in the Gleyic Kastanozems soil was revealed. There is no redistribution of natural radionuclides (226Ra, 232Th, 40K) in soil profiles over time. The minimum specific activity of radionuclides is recorded in Umbric Fluvisols soil located in the floodplain of the Don River. A linear dependence of the specific activity of 137Cs on pH and humus was established (r=0.62 and 0.88, respectively). Keywords: RADIOECOLOGICAL MONITORING, ROSTOV NPP, NATURAL AND ARTIFICIAL RADIONUCLIDES, ORGANIC MATTER, pH

Изучение радиоактивности вод горных рек Кабардино-Балкарской Республики с использованием детектора NaI в низкофоновой защите

The results of studies of the radioactivity of the waters of the mountain rivers of the Kabardino-Balkarian Republic using the NaI detector in low-background protection are presented. The paper presents a method of low-background gamma-ray spectrometry for detecting radioactivity in drinking water, which is an effective method, has high sensitivity to radioactive radiation and allows you to accurately determine the level of radioactivity. The MULTIRAD MKS-01A spectrometric installation was used to measure radiation in samples under low background conditions. The identification and calculation of the volumetric activity of radionuclides was carried out using special software "Progress". Concentration levels and specific activity distribution of natural radionuclides 137Cs, 232Th, 40K, 226Ra and 222Rn were studied. Water samples were taken from the rivers of the Baksan, Cherek gorges and the Malka River of the Kabardino-Balkarian Republic. Studies have shown that radiation levels were within the norm set for drinking water.

Can metals and radionuclides in Shiveluch (Kamchatka) volcanic ash affect human health?

Volcanic eruption is associated with the release of large volumes of pollutants in the environment, which can pose a risk to humans and other living organisms. The elemental and radioisotope composition of ash released during the Shiveluch Volcano eruption in 2023 was analyzed using ICP-MS and low-background gamma spectrometry. The ash consisted of 59% SiO2, 16.7% Al2O3, 5.3% CaO, 4.6 % Na2O, 4.5% Fe2O3, 1.4% K2O, 0.48% TiO2, 0.17% P2O5, 0.15% S, 0.078% MnO and 44 trace elements. Hazard Quotient and Hazard Index were calculated in order to evaluate the potential health risks to children and adults due to exposure to contaminants via inhalation, ingestion, and dermal contact. All values were below the unit, indicating a low probability of non-carcinogenic and cancerogenic risk occurrence in target groups. The average activity concentrations of the natural radionuclides were 350, 12.4 and 4.84 Bq/kg for 40K, 226Ra and 232Th. Radiological indices, including external and internal risk assessment, radium equivalent activity, annual effective dose, gamma index, and excess lifetime cancer risk were calculated to estimate the radiological hazard for the population. The values of all indices were below the recommended safety limits, indicating a low level of hazard for the exposed population.

Radiological hazard assessment of soil from Kasik oil refinery, Nineveh, Iraq

This study explored soil samples in a depth about 10–15 cm, 20 Soil samples were collected systematically from various locations to ensure a comprehensive assessment of the site within Kasik oil refinery, Nineveh Governorate, Iraq, whereby the determination of three natural radionuclides' specific activities was carried out via A p-type coaxial HPGe γ-ray spectrometer, manufactured by CANBERRA, USA. Natural radioactivity in soil is a significant factor for assessing environmental radiation exposure and potential health risks. The 226Ra, 232Th, and 40K radionuclides' mean specific activities in the soil samples were in the 13.10–33.43 Bq/kg, 10.58–22.76 Bq/kg, and 104.90–442.16 Bq/kg ranges, respectively, with overall means of 21.44 Bq/kg, 15.96 Bq/kg, and 255.50 Bq/kg, which are within the worldwide mean levels. The mean radium-equivalent activity (Raeq) was 63.94 Bq/kg, and thus below the 370 Bq/kg international limit. All of the samples' representative level index (Iɣ) and internal and external hazard indices (Hin and Hex) were below the limit of unity, indicating low radiation hazards. The absorbed dose rate resulting from the three primordial radionuclides was in the 19.92–41.46 nGy/h range (mean: 30.20 nGy/h), with an annual effective dose of 0.04 mSv/y. The mean excess lifetime risk of cancer was found to be 0.15 × 10⁻³, and thus under the 0.29 × 10⁻³ world average. The study's results indicate that the natural radionuclides' measured specific activities in the soil samples are below the world recommended values, suggesting that the investigated area is safe in terms of radiological health risks.

Determination of Natural Radioactivity Levels and Radiation Hazards from the Soil of Tin Mining in Kyerwa District, Tanzania

Gamma spectrometry was used to determine the activity concentrations of the natural radionuclides 226Ra, 232Th, and 40K in soil samples from the Tin mining in Kyerwa District, Tanzania. The study findings revealed that the mean activity concentrations of 226Ra, 232Th, and 40K were 90.68, 65.45, and 630.95 Bq/kg, respectively. These values were all greater than the average global activity concentrations for 226Ra, 232Th, and 40K which are 32 Bq/kg, 45 Bq/kg, and 420 Bq/kg, respectively. Assessments of the radiological risks associated with these naturally occurring radionuclides were done. In this case, the radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and radioactivity level index (Iγ) were calculated. The results show that the mean values of Raeq, Hex, Hin, and Iγ were 230.6 Bq/kg, 0.628, 0.861, and 0.831, respectively. These results were below the global criteria levels for Raeq, Hex, Hin, and Iγ, which are 370 Bq/kg, 1, 1, and 2, respectively. Estimates for the absorbed dose rate in the air (DR), the annual effective dose equivalent (AEDE), and the annual gonadal equivalent dose (AGED) were also made. The findings revealed that the corresponding mean values for DR, AEDE, and AGED were 106.8 nGy/h, 1.07 mSv/y, and 744.4 μSvy-1. The mean values exceeded the global average value of 57 nGy/h for DR, 0.07 mSv/y for AEDE, and 2984 Sv/y for AGED. Therefore, Tin mining activities in the Kyerwa District could endanger the mining community from natural radioactive sources. In this study, therefore, we recommend performing a periodic inspection of the mining areas, monitoring the mining workers, and determining the level of activity and concentrations of different radionuclides in the mining area.