Natural Radionuclides Research Articles

An Overview of the Measurements of Primordial Radionuclide Concentrations in Soil and Radon Concentrations in Water Samples

Radiation physics has significantly improved health science, revealing the impact of radioactive materials on humans. These contaminants damage soil and water, leading to health issues like stomach, lung, and leukemia. Radon, a byproduct, poses a significant threat to human health, particularly lung and stomach cancer. Identifying radioactive soil sites is crucial for assessing health concerns among agriculture and construction workers, as natural radionuclides can cause radiological damage. Monitoring these materials can help to assess exposure-related health risks. The goal of this review is to overview and consolidate the works executed between 2007 and 2024 in several countries, including Romania, Turkey, Jamaica, Nigeria, Jordan, Serbia, Spain, Saudi Arabia, Armenia, China, Brazil, Sudan, India, Syria, Iraq, Tunisia, Pakistan, Qatar, and Yemen. Articles commonly employ (HPGe), RAD-7, and CR-39 techniques to measure primordial radionuclides and radon levels. The latest analysis revealed that Nigeria has a significantly higher average radon measurement of 36.1 Bq/L in its drinking water, above the global benchmark threshold of 11.1 Bq/L. The article also, reviews primordial radionuclides in soil research articles in 10 nations. Serbia has the highest 226Ra and 40K soil Bq/kg, which exceeded standards of 32, and 420 Bq/kg of 226Ra and 40K, respectively, while Turkey and Jordan have the lowest values. India has the highest 232Th, and health and safety concerns are addressed. This review work shows that naturally occurring background radiation from radionuclides in soil and radon concentrations in water samples typically has a substantial health impact, posing a major radiation risk to the residents of certain areas. Consequently, our analysis showed that residents should avoid some areas due to radiological hazards. Finally, this review evaluates and elucidates the several factors that influence the elevated and reduced levels of radon in consumption water and the primordial radionuclides activity in soil samples in each country.

Natural radioactivity in food crops and soil and estimation of the concomitant dose from tin mining areas in Nigeria

Mining of mineral ore is considered one of the anthropogenic sources of elevating the activity concentrations of the natural radionuclides in the environment, which in turn causes an increased risk of human exposure via the food chain. In an attempt to evaluate the radiological burdens resulting from tin mining activities in Nigeria, farm soil and sixty-two samples of different food crops grown around tin mining areas were evaluated for the activity concentrations of 226Ra, 232Th, and 40K using a high-purity germanium detector. The mean activity concentrations of 226Ra, 232Th and 40K in soil were 64.6 ± 29.5, 72.03 ± 28.73 and 680.6 ± 324.3 Bq/kg, respectively. These values were found to be higher than their corresponding world average values. However, the mean activity concentrations of the measured radionuclides in plants were below their respective world average values, as reported by UNSCEAR. The overall average annual ingestion dose due to the consumption of the analysed plants was 151 µSv/y, which is below the reported world average value of 290 µSv/y. The results obtained show that the hazard indices were low enough to cause any immediate radiological health complications due to the ingestion of the crops grown in the studied areas.

Effects on local atmospheric environment of volcanic ash from Sakurajima volcano, inferred from atmospheric deposition of Potassium-40 at Kagoshima City, Japan

In this study, we statistically demonstrated that an anomalous high of 40K fallout in the atmospheric fallout in Kagoshima City is caused by heavy ashfall associated with eruptions of Sakurajima volcano. Sakurajima is one of the most active volcanoes in Japan, and its repeated explosive eruptions cause large amounts of ash to fall on Kagoshima City. The fallout of crust-derived natural radionuclides, 40K, 212Pb, and 214Bi, from the atmosphere in Kagoshima City showed a significant correlation with the number of eruptions of Sakurajima volcano and the amount of ashfall in Kagoshima City. In contrast, no significant correlation was found between 40K and 7Be fallout. The 40K fallout indicates that almost all of the atmospheric fallout in Kagoshima City is composed of volcanic ash particles. The contribution from mineral and sea salt particles other than volcanic ash is minimal. The mass balance of the observed 40K fallout, ashfall, and atmospheric fallout yield indicates that there is a significant amount of volcanic ash deposition that is not accounted for as ashfall. In most cases, the ash deposition observed as ashfall is only 30–70 wt% of the total deposition collected as atmospheric fallout samples, and the remaining portion is fine-grained and behaves as suspended volcanic ash particles, which significantly impact the atmospheric environment.

Radiation protection for Gabes phosphate area residents: Assessing natural radioactivity in soil and potable water samples

Phosphate mining activities are recognized to be one of various industrial processes generating enhanced Naturally Occurring Radioactive Materials (NORM) by introducing natural radionuclides into the surrounding soils and water bodies, posing a risk to human health.This study was carried out to assess the level of natural radionuclides in soils and potable waters collected from the phosphate area of Gabes city, located in southeastern Tunisia, and to evaluate radiation protection measures by estimating radiological health hazard parameters. Gamma spectrometry system employing an HPGe detector was used in this study to assess 40K, 232Th and 226Ra activity concentration in soils. The average values were found to be 163.7, 14.5, and 7.7 Bq kg−1, respectively, which were lower than worldwide average values. The radiological hazard parameters assessed in this study were radium equivalent activity (Ra-eq), external hazard index (Hex), external gamma absorbed rate (GDR), external annual effective dose (Deff) and excess lifetime cancer risk (ELCR). The calculated average values of the above-mentioned parameters were of 41 Bq kg−1, 0.1, 20.2 nGy h−1, 24.8 μSv y−1 and 8.7 × 10−5 all of which were found to be below their permissible standards.For potable water samples, the activity concentrations of radium were analyzed using an HPGe detector and those of uranium were determined by alpha spectrometry. The average activity concentrations of uranium and radium isotopes in underground water samples were found to be higher than those obtained in tap water samples. For both types of water, the average values for all radionuclides were found to be below their respective reference limits.The annual ingestion effective doses were also estimated in this study. The estimated average values for infant and children for underground water samples were higher than the permissible limit of 100 μSv y−1 set by WHO. The 226Ra was the main contributor to the effective doses for different age categories, followed by 228Ra.

Soil –plant transfer factors of radionuclide in cassava (Manihot esculenta) around a cement factory in Kogi State, Nigeria

Mathematical models are typically used to predict how naturally occurring radionuclides migrate from soil to plants. A transfer factor (TF) is the ratio of radionuclide concentration (Bq kg−1) of plant to soil in dry weight. This research aimed at determining the soil to plant transfer factor of radionuclide, in order to access the level of migration of natural radionuclide from soil to a selected cultivated crop (cassava), due to cement production activity around a cement factory. Soil and cultivated plant samples were collected randomly at different locations around the factory. The collected samples were analyzed using NaI (Tl) gamma (γ) spectroscopy. The average transfer factor (TF) from soil to plant was found to be 0.428, 0.531 and 0.398 for 226Ra, 232Th and 40K, respectively. The TF indicates that about 42.8%, 53.1% and 39.8% of 226Ra, 232Th and 40K, respectively, were transferred from soil to cassava and varies in the order of 232Th (0531) > 226Ra (0.428) and 40K (0.398). All the transfer factors were below the world standard of unity. There exists a positive Pearson correlation among the three radionuclides in the soil and plant samples. The three radionuclides were detected in soil and food samples, and a positive correlation between them suggests that they originated from the same source for each environmental matrix. The results determined the value of TF of soil to cassava (Manihot esculenta) is at a safe level to the farmland around the cement factory and have no immediate radiological health implications due to cement production.

Health Impacts of Natural Background Radiation in High Air Pollution Area of Thailand.

Chiang Mai province of Thailand is known for having the highest natural background radiation in the country, as well as being recognized as one of the world's most polluted cities for air quality. This represents the major contributor to the development of lung cancer. This research aims to estimate the comprehensive dose of both internal and external exposure due to natural background radiation and related health perspectives in the highly polluted area of Chiang Mai. The average values of indoor radon and thoron concentrations in 99 houses over 6 months were 40.8 ± 22.6 and 17.8 ± 16.3 Bq/m3, respectively. These results exceed the worldwide value for indoor radon and thoron (40 and 10 Bq/m3), respectively. During burning season, the average values of indoor radon (56.7 ± 20 Bq/m3) and thoron (20.8 ± 20.4 Bq/m3) concentrations were higher than the world-wide averages. The radon concentration in drinking water (56 samples) varied from 0.1 to 91.9 Bq/L, with an average value of 9.1 ± 22.8 Bq/L. Most of the drinking water samples (87%) fell below the recommended maximum contamination limit of 11.1 Bq/L. The average values of natural radionuclide (226Ra, 232Th and 40K) in 48 soil samples were 47 ± 20.9, 77.9 ± 29.7 and 700.1 ± 233 Bq/kg, respectively. All values were higher than the worldwide average of 35, 30 and 400 Bq/kg, respectively. The average value of outdoor absorbed gamma dose rate (98 ± 32.5 nGy/h) exceeded the worldwide average of 59 nGy/h. Meanwhile, the average activity concentrations of 226Ra, 232Th and 40K in 25 plant food samples were 2.7 ± 0.1, 3.2 ± 1.6 and 1000.7 ± 1.9 Bq/kg, respectively. The 40K concentration was the most predominant in plant foods. The highest concentrations of 226Ra, 232Th and 40K were found in Chinese cabbage, celery and cilantro, respectively. The total annual effective dose for residents in the study area varied from 0.6 to 4.3 mSv, with an average value of 1.4 mSv. This indicates a significant long-term public health hazard due to natural background radiation and suggests a heightened radiation risk for the residents. The excess lifetime cancer risk value (5.4) associated with natural background radiation was found to be higher than the recommended value. Moreover, the number of lung cancer cases per year per million average of 25.2 per million persons per year was in the limit range 170-230 per million people. Overall, our results will be used for future decision making in the prevention of lung cancer risk associated with natural background radiation.

Microvolume analysis of 226Ra by inductively coupled plasma mass spectrometry: Environmental applications to high-resolution profile of wetland soil pore waters

BackgroundThe release to the environment of natural radionuclides like 226Ra due to human activities have raised concerns about human and ecosystem exposure. 226Ra’s resemblance to calcium and involvement in biological processes accentuate the importance of understanding its geochemical behavior and migration pathways. Soil and sediment pore waters provide valuable information but have proved to be challenging to analyze, requiring to push the limits of current sample preparation and detection methods often not scaled for low concentrated microvolumes of samples. A more efficient and accurate analytical method is therefore needed to get reliable data to support hydro-geochemical modeling. ResultsWe describe here a novel comprehensive approach for accurate 226Ra quantification in pore waters of a wetland located downstream of the former Rophin uranium mine. In order to highlight the migration of 226Ra between the different soil layers, microvolumes of soil pore waters were in situ sampled up to 50 cm depth employing Diffusive Equilibrium in Thin-Films (DET) probes. The workflow included spiking DET extracts with an in-house 228Ra tracer, specific solid-phase extraction with 50 mg of AnaLig Ra-01® resin, and elution fraction calcination. This process eliminated interferences and simplify the analysis matrix. Quantification relied on isotope dilution after measurement by ICP-MS hyphenated to a desolvator module and to a microsampler (150 µL injection). The resulting 1 cm-high-resolution profile revealed unusual 226Ra enrichment with depth, signs of Ra mobility from the solid contamination source. These elements are essential for assessing 226Ra distribution coefficients across soil horizons and subsequent wetland remobilization considerations. Significance and noveltyThis first methodological advance for 226Ra constitutes a significant step to understand 226Ra behavior i.e., to quantify its activity level, fluxes inside of wetland soils or at the interface overlying waters/sediments. Its potential extension to studies involving other elements underscores its broader applicability in environmental research. The findings contribute to evidence-based decision-making for environmental protection and management, aiding in the preservation of ecological integrity and human health.

Radiological assessment of commonly food crops in Southwestern Nigeria

Natural radionuclides are present in food items at different levels and are influenced by factors like background radiation, climate, and agricultural practices. These radionuclides play a crucial role in humans' internal radiation exposure. Notably, radionuclides within the decay series 238U and 232Th as well as 40K are significant concerns in radiation protection due to their prevalence and potential health risks. The activity concentrations of radionuclides 238U, 232Th, and 40K in several food crops consumed within Lagos city in Nigeria were measured using gamma spectrometry. The concentrations of 238U, 232Th, and 40K ranged from 0.90 to 55.30, BDL (Below Detection Limit) to 161.60 and 10.30 to 1075.20 Bqkg−1, respectively. The average radionuclide activity concentrations are below the acceptable global level, or the worldwide average values set by the United Nations Scientific Committee on the Effects of Atomic Radiation in 2000 (UNSCEAR, 2000), which are 35, 30, and 400 Bqkg−1 for 238U, 232Th, and 40K, respectively. The study calculated the annual effective dose for individuals consuming the studied food items, and the annual internal dose from ingesting was found to be 8.95 × 10–04 μSvy−1. It’s noteworthy that this computed value is below the worldwide value of 0.32 mSv y−1 set for the public. Additionally, the excess lifetime cancer risk (ELCR) value was 3.13 × 10−3 μSvy−1, which is within the world safe limit value (2.9 × 10−4 μSvy−1). Therefore, there is no potential radiological risk associated with the measured data.

Utilization of metal and radionuclide concentrations to assess the influence of shrimp farming on the geochemical characteristics of sediments.

This article assesses the environmental impacts of aquatic biota cultivation, focusing on shrimp farming in Brazil's Northeast, as this practice has proven to be one of the main sources of economic growth in the region. For this purpose, sediment samples were collected from areas impacted and not directly impacted by shrimp farming, and concentrations of key geochemical parameters such as salinity, various elements (K, P, Cu, Mn, Pb, Zn, Al, Ca, Fe, Mg, and Na), and natural radionuclides (K-40, Ra-226 and Ra-228) were compared using statistical tools. Element concentrations were determined using ICP-OES, and naturally occurring radionuclide concentrations were obtained through gamma spectrometry. Statistical tests, such as ANOVA and/or Mann-Whitney, cluster analysis, and principal component analysis, were applied to the results. Additionally, the ERICA Tool software was employed to estimate deleterious effects on both human and non-human biota. Descriptive statistics reveal variability in sediment parameters around shrimp farming. ANOVA and Mann-Whitney tests compare concentrations of shrimp farm sediment and not directly impacted sediment, showing non-significant differences for most elements. pH and salinity, crucial for shrimp health, exhibit higher values in shrimp farm sediment. Alkali and alkaline earth metals, including K and Na, show no significant differences. Factor and cluster analyses suggest that certain elements, mainly radionuclides, are influenced by sediment variability. Hazard indices for naturally occurring radionuclides indicate negligible risk to both human and non-human biota, reinforcing the absence of adverse effects from shrimp farming activities. This study provides a comprehensive analysis of the environmental impacts of shrimp farming, emphasizing the importance of monitoring geochemical parameters for coastal environmental management.

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.

Distribution of some natural and artificial radionuclides in soil from the city of Bitola (Macedonia) and its environs.

The aim of the study is a thorough investigation of the radioactivity level in soils of the town of Bitola (Macedonia) and its environs. Topsoil samples collected from 58 locations within a 5×5 km grid were analysed. Serving as a screening, gross alpha and beta activity measurements were performed using gas-flow proportional counter. Gamma-spectrometric measurements revealed the presence of three natural (40K, 226Ra, 232Th) and one artificial radionuclide (137Cs) in the samples. The activity concentrations of these radionuclides were consistent with the results of similar studies in neighbouring areas. Spatial distribution maps and factor analyses have revealed that the activity concentrations of the natural radionuclides are strongly influenced by geology and have no significant influence from human activities. A correlation of 137Cs activity concentrations with terrain elevation was also observed. The aim of the study is a thorough investigation of the radioactivity level in soils of the town of Bitola (Macedonia) and its environs. Topsoil samples collected from 58 locations within a 5×5 km grid were analysed. Serving as a screening, gross alpha and beta activity measurements were performed using gas-flow proportional counter. Gamma-spectrometric measurements revealed the presence of three natural (40K, 226Ra, 232Th) and one artificial radionuclide (137Cs) in the samples. The activity concentrations of these radionuclides were consistent with the results of similar studies in neighbouring areas. Spatial distribution maps and factor analyses have revealed that the activity concentrations of the natural radionuclides are strongly influenced by geology and have no significant influence from human activities. A correlation of 137Cs activity concentrations with terrain elevation was also observed.

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.

On transfer factors of natural radionuclides and radiological health risks assessment of some fruit samples

Abstract In this study, the activity concentration of artificial and natural radionuclides such as 137Cs, 40K, 226Ra, and 232Th was measured in the soil under the roots; leaves; and fruits of six different fruit trees namely mulberry, fig, apricot, olive, black and white grapes in Koya district, Erbil province, Iraq. For this purpose, a high-resolution gamma spectroscopy consisting of a high-purity germanium (HPGe) detector was used. In addition, the associated radiological risks from soil and fruits were assessed by calculating several radiological indices such as radium equivalent (Raeq.s), absorbed dose (Ds), indoor (AEDEs indoor ) and outdoor annual effective doses (AEDEs outdoor ), internal and external hazard indices, gamma index and the excess lifetime cancer risk (ELRCs). The results show that consuming these fruits is radiologically safe because they can cause an annual effective dose of about 61.72 μSv y−1 and excess lifetime cancer risk of 0.06 × 10−3 Sv y−1. On the other hand, transfer factors of radionuclides from soil to leaves; and from soil to fruits were studied. The transfer factor analysis revealed that among the studied fruits and radionuclides, apricot and mulberry exhibited the highest transfer factors for 40K, with values of 1.85 and 1.87, respectively.

Chemical and radiochemical characterization of phosphogypsum from Poland

Abstract The current study presents the results of the chemical and the radiochemical characterization of phosphogypsum obtained from the former Wizów Chemical Plant in Poland. Phosphogypsum is a residue obtained from phosphoric acid production. Phosphogypsum mainly contains calcium sulfate dihydrate and impurities originating from the source phosphate rock, including toxic trace elements and natural radionuclides. The phosphogypsum stacks occupy a large area and are an environmental issue today. The project “Phosphogypsum Processing to Critical Raw Materials”, currently realized at the Institute of Nuclear Chemistry and Technology, focuses on the use of phosphogypsum from the Polish stacks as material to recover rare earth elements (REEs). The remaining gypsum matrix can be used as an inexpensive material in construction. The chemical and radiological characterization of the radioactive isotopes present in phosphogypsum was performed by using inductively coupled plasma mass spectrometry (ICP-MS) and the gamma spectrometry technique. The radioactivity of the Polish phosphogypsum was then compared with the radioactivity of the phosphogypsum waste present worldwide.

Accumulation of Natural and Artificial Radionuclides by Medicinal Plant Raw Materials Using Nettle Leaves as an Example

Accumulation of Natural and Artificial Radionuclides by Medicinal Plant Raw Materials Using Nettle Leaves as an Example

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.

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) under flooded and unflooded conditions in Hanoi, Vietnam

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) in Hanoi, Vietnam have been investigated using a low background gamma spectrometer with an HPGe detector (Model-GC5019). Twenty pairs of soil and water spinach samples in two environmental conditions, i.e., flooded and unflooded, were collected for measuring the activity concentrations and determining the soil-to-plant transfer factors (TFs) of natural radionuclides. For water spinach, stems and leaves were collected as the main parts for human consumption and livestock food. The TF of 40K is within the range of 0.32–2.49, which is greater than that of 228Ra (0.01–0.17) and 226Ra (0.01–0.13). The geometric means (geometric standard deviations) of the TFs are 1.17(1.89), 0.05(2.41) and 0.04(1.88) for flooded sites, and 0.89(1.73), 0.03(2.12) and 0.03(1.82) for unflooded sites, respectively. Comparing between the flooded and unflooded sites, the TFs are all greater at the flooded sites.

Improving the detection limit in lung counting with a segmented HPGe detector

A segmented High-Purity Germanium (HPGe) detector with a thin front segment together with various active and passive shield configurations was simulated with the aim of reducing the level of background events in lung counting applications. Eight different detector models were tested in a Geant4 simulation environment in a scenario where inhaled 241Am activity was deposited in the lungs of an ICRP adult reference computational phantom. In lung counting measurements, the Compton continuum in the spectrum is generated by the natural and man-made radionuclides inside the human body and the natural background radiation from the environment. The reduction in Minimum Detectable Activity (MDA) using the segmented HPGe detector combined with an active shield compared to a model with a single germanium crystal was investigated. A reduction in MDA up to 30% and 66% was obtained for internal and external sources, respectively. The results show that the detection limit and/or the measurement time in lung counting can be reduced using such a detector configuration. Furthermore, combining the segmented HPGe detector with an active shield would be particularly useful in field measurements.

Soil-to-plant transfer factor of natural radionuclides and associated health risk in some vegetable species in arid area

Soil-to-plant transfer factor of natural radionuclides and associated health risk in some vegetable species in arid area

Migration of trace elements and radioisotopes to various fractions of solid wastes generated as a result of the sewage sludge incineration process

The research was aimed at providing new knowledge in the field of chemical characteristics of solid waste generated in the process of combustion of sewage sludge in fluidized bed furnaces. The research material consisted of disposed fluidized beds (DFB), sewage sludge ash (SSA) and air pollution control residues (APC) from three Polish installations for the thermal treatment of sewage sludge. Natural radionuclides as well as anthropogenic isotope 137Cs were determined in the tested materials and the migration of a wide spectrum of trace elements to various waste fractions generated in the process of sewage sludge combustion was examined. It was observed that both radioisotopes and most of the trace elements determined accumulate in SSA and DFB, while the APC fraction contains a much smaller amount of them. The exceptions are mercury and selenium, whose volatile compounds migrate to the exhaust gas dedusting system and accumulate in the APC fraction (up to 40 mg/kg and 13 mg/kg, respectively). A potential threat from the 226Ra isotope in SSA is identified in the context of the management of this waste in the production of building materials because the typical activity of 226Ra in SSA collected from areas with very low Ra content in natural environment exceeds 1.5–6 times the activity of this isotope in conventional cement mixtures. When managing SSA and DFB, special attention should be paid to the content of metalloids such as As, B and Se, due to the high content of mobile forms of these elements in the mentioned materials.