High Background Radiation Research Articles

A model comparison of diffusion-controlled radon exhalation from solid and cavity walls with application to high background radiation areas.

Radon exhaled from building material surfaces is an important source of indoor radon. Yangjiang, located in the southern part of mainland China, is well-known as a high background radiation area (HBRA). Rather, high levels of radon and thoron concentration have been observed in adobe and brick houses. Reducing the indoor radon concentration remains an important issue in the high background radiation areas of China and the world. Generally, the walls of Chinese dwellings are solid. In this paper, a simple one-dimensional model for predicting the radon diffusion in a cavity wall is proposed, and an analysis formula describing the radon exhalation rate from cavity wall surfaces is presented. The influence on the radon exhalation rate due to leakage through structural joints and building material cracks is analyzed. The simulation results indicate that the radon exhalation rate from a cavity wall surface is far lower than that from a solid wall. The structure of cavity walls themselves is therefore useful as a mechanism for reducing the indoor radon in high background radiation areas across the world.

A unique high natural background radiation area – Dose assessment and perspectives

The biological effects of low dose-rate radiation exposures on humans remains unknown. In fact, the Japanese nation still struggles with this issue after the Fukushima Dai-ichi Nuclear Power Plant accident. Recently, we have found a unique area in Indonesia where naturally high radiation levels are present, resulting in chronic low dose-rate radiation exposures. We aimed to estimate the comprehensive dose due to internal and external exposures at the particularly high natural radiation area, and to discuss the enhancement mechanism of radon. A car-borne survey was conducted to estimate the external doses from terrestrial radiation. Indoor radon measurements were made in 47 dwellings over three to five months, covering the two typical seasons, to estimate the internal doses. Atmospheric radon gases were simultaneously collected at several heights to evaluate the vertical distribution. The absorbed dose rates in air in the study area vary widely between 50 nGy h−1 and 1109 nGy h−1. Indoor radon concentrations ranged from 124 Bq m−3 to 1015 Bq m−3. That is, the indoor radon concentrations measured exceed the reference levels of 100 Bq m−3 recommended by the World Health Organization. Furthermore, the outdoor radon concentrations measured were comparable to the high indoor radon concentrations. The annual effective dose due to external and internal exposures in the study area was estimated to be 27 mSv using the median values. It was found that many residents are receiving radiation exposure from natural radionuclides over the dose limit for occupational exposure to radiation workers. This enhanced outdoor radon concentration might be as a result of the stable atmospheric conditions generated at an exceptionally low altitude. Our findings suggest that this area provides a unique opportunity to conduct an epidemiological study related to health effects due to chronic low dose-rate radiation exposure.

Geospatial Modeling of Radon-Prone Areas

Methods for identification of potentially radon-prone areas using geospatial analysis in ArcGIS 10.6 software environment and mathematical modeling in SPSS 19.0 on the example of high background radiation area have been developed. High level of natural radioactivity associated with uranium content in environment objects and natural uranium occurrences, and also the spatial density of faults (reliable and unreliable) and lineaments were taken into account as well as the distance from uranium mine located nearby.
 The method of linear discriminant functions was used to make a math model for determining the level of radon hazard. To do this, data on all locations were divided into training and test samples. Determination of predictors of the mathematical model was performed using Fisher's criterion by their sequential inclusion in discriminant equations. Among the considered 13 factors of radon hazard, seven of them turned out to be informative. For them, canonical coefficients were calculated using the least squares method for first- and second-order polynomials. Based on the values of discriminant functions, a territorial map was constructed to assign the new location to a certain level of radon hazard.
 The maps obtained present the correlation of the radon-prone areas with the zones of high spatial density of faults and lineaments, and confirmed by the data of direct indoor radon measurements. In a limited number of measurements, the methods might get a good help in prioritization for round-the-country radon survey. As far as the model for identification of potentially radon-prone areas is mainly based on geological studies, the further research is supposed to be directed to its approbation for a different geological environment of the Ukrainian shield.

Variation in value of annual effective natural gamma dose rate during lockdown in the pandemic situation in various countries

ABSTRACT Coronavirus Disease 2019 (COVID-19) has been declared officially as the pandemic worldwide. This novel coronavirus affects almost the whole world and it can quickly spread among the population in several ways. This has initially come from China and within a few months, covers the overall world. Therefore, many countries have decided to restrict the movement through lockdown to control the spreading of COVID-19 novel virus among the population. During this lockdown condition, almost all except few essential people stay at home means staying inside of houses 24 × 7 hours. The study aims to calculate the impact of this lockdown condition on the annual natural gamma radiation dose. The values of indoor gamma radiation are not the same as the outdoor gamma dose rate; the ration between indoor and outdoor gamma dose rates varies based on country to country. In this study, we have used indoor-outdoor gamma dose rate ratio which was reported by UNSCEAR (United Nations Scientific Commission on Effects of Atomic Radiation) and calculated the variation of annual dose rate during this pandemic condition that will be helpful for estimation of gamma expose scale for this year of various countries. The higher ratio of indoor and outdoor gamma dose rates showed a high variation in annual dose rate. It was found that the change in annual dose rate continuously increases with respect to the number of days of lockdown. This will also affect much more at high background radiation areas as compared to the low background area.

Natural environmental radiation mapping in parts of Meghalaya, India

This paper presents new data on natural environmental radiation mapping in Meghalaya for the first time in India. Two alternate methods have been used to map (1) a regional low-density environmental radiation mapping by using radiation meters, (2) high-resolution radiation mapping of Shillong Basin using the data generated by an integrated litho- and pedo-geochemical sampling program using gamma ray spectrometric measurements on both rock and soils samples. The variation in radio-elemental concentrations and radiation levels are related to bedrock geology and structures. The high levels of radiation levels are observed in the areas occupied by Mylliem Granite (3.935 mSv/a, 51 μR/h, 178.066 nGy/s) followed by South Khasi Batholith with pink feldspar (2.42 to 3.652 mSv/a, 31 μR/h, 109.502–165.249 nGy/s), graphitic schists (avg. 52.10 pGy/s, 1.06 mSv/a), Chlorite Schist (avg. 51.16 pGy/s, 1.13 mSv/a), Phyllites (avg. 47.98 pGy/s, 1.06 mSv/a), volcanics (avg. 46.9 pGy/s, 1.04 mSv/a), The Chlorite schist of Tyrsad formation (21 μR/h, 1.643 mSv/a, 74.321 nGy/s) and Barapani arenite (16 μR/h 1.21 mSv/a, 54.773 nGy/s), Tertiary sandstone (21 μR/h, 1.633 mSv/a, 73.885 nGy/s), Shella subgroup (12 μR/h, 0.914 mSv/a, 41.376 nGy/s), Langpars (13 μR/h, 1.006 mSv/a, 45.502 nGy/s), Upper Mahadek (26 μR/h, 2.062 mSv/a, 93.298 nGy/s), Lower Mahadek (38 μR/h, 2.935 mSv/a, 132.785 nGy/s), and the lowest environmental radiation levels are observed over Sylhet traps (9 μR/h, 0.725 mSv/a, 32.786 nGy/s). The soils generally show higher radiation levels as compared to their bed rocks. Comparisons are made with high radiation areas of the world results, showing that they are lower than high background radiation areas. These radiation images are the first series of environmental images for Meghalaya and will serve as the baseline data for the upcoming uranium mining projects in Meghalaya. Baseline environmental radiation images are necessary information to policy makers and provide a sound basis for addressing the public concerns for radiation levels.

Screening of Extremophile Microalgae Isolated from High Background Radiation Areas as Source of Bioactive Materials

Background: Microalgae are the source of various compounds with high potentials for being used in different industries. The production of such compounds can be raised under extreme conditions. In the present study, four cyanobacteria and one coccoid green alga were examined which were isolated from hot springs in high background radiation areas in Ramsar, a city in the north of Iran. Methods: Cadmium adsorption from aqueous solution, response towards cadmium stress, antioxidant activity, total phenolic compound and drought tolerance were investigated in these microalgae. Results: The results showed that these extremophile microalgae contain valuable biological compounds which can be useful in remediation of heavy metals from contaminated water and soils and pharmaceutical applications. The unicellular cyanobacterium, Chroococidiopsis thermalis IBRC-M50002, was the best strain with the highest biological activity in various testes such as cadmium adsorption (225 mg g-1), cadmium tolerance stress (100 mg ml-1), antioxidant activity (IC50= 18 μg mg-1) and total phenol content (100 μg ml-1). The coccoid green algae Grasiella emersonii IBRC-M50001, also exhibited significant antioxidant activity (IC50=10 μg mg-1) and total phenol compound (116 μg ml-1), but its cadmium adsorption, tolerance at cadmium stress and desiccation were lower than Chroococidiopsis thermalis. Conclusion: HBRAs microalgae, isolated from extreme conditions, are useful microorganisms for the production of bioactive substances and natural antioxidants. In other words, they exhibited high capacity to be used in pharmaceutical, industrial and commercial applications.

Geochemical behavior of uranium and thorium in sand and sandy soil samples from a natural high background radiation area of the Odisha coast, India.

Owing to their natural radioactivity, uranium (U) and thorium (Th) play significant roles in environmental sciences for monitoring radiation dose and in geological sciences for understanding sedimentary processes. The Odisha coastal area, in eastern India, is a well-known high background radiation area that is rich in monazites and rutile. This area was selected to study geochemical characteristics of U and Th in sand and sandy soil samples. The concentrations of U and Th were measured using inductively coupled plasma mass spectrometry (ICP-MS). The median, geometric mean, and standard deviation for U were determined to be 6, 4.5, and 2.5μg/g and for Th were186, 123.3, and 3.1μg/g, respectively. Major element concentrations were evaluated using X-ray fluorescence spectroscopy to get the mineralogical composition and state of chemical weathering. The ratios of Th/U and Th/K varied from 4 to 37 and from 13 to 1058, respectively. These results clearly indicate that the samples from the coastal region were formed in an oxidizing and intense chemical weathering terrestrial environment with an enrichment of radiogenic heavy minerals (monazites and zircon) and clay mineral association. Since the majority of the samples have undergone moderate to intense weathering in the oxidizing environment, U is leached from the soil and sand matrix. Eventually, Th resides in the matrix and becomes a major source for radiation exposure in the environment. The high ratios of Th/U, along with the strong positive correlation between Th and P2O5, evidence the enrichment of the Th-bearing radioactive mineral, monazite, in these samples.

Exposures from radon, thoron, and thoron progeny in high background radiation area in Takandeang, Mamuju, Indonesia

Abstract The exposure from radon, thoron, and thoron progeny was measured for 45 dwellings in high background radiation area in Takandeang, Indonesia with ambient dose equivalent rate ranging from 0.34 μSv h−1 to 1.90 μSv h−1. The measurement was taken using passive radon and thoron discriminative detector and thoron progeny detector. This measurement was taken from November 2018 to October 2019, and within one month the detector would be replaced with a new detector. The concentrations of radon, thoron, and thoron progeny were calculated as 42–490 Bq m−3, 20–618 Bq m−3, and 4–40 Bq m−3, respectively. The concentrations for outdoor were 49–435 Bq m−3, 23–457 Bq m−3, and 4–37 Bq m−3, respectively, and the annual effective dose was 9.8–28.6 mSv y−1. Based on the result of Spearman’s correlations analysis between the indoor radon and thoron concentrations and between the indoor thoron progeny and thoron concentrations, we suggest that exposure to thoron cannot be predicted from exposure to radon, and the equilibrium equivalent thoron concentration has a large uncertainty when it is estimated from thoron concentration assuming a single thoron equilibrium factor.

Radionuclide activity concentration in soil, granites and water in a fluorosis endemic area of India: An oral health perspective

BackgroundThe idea that hilly areas have a high background radiation which in turn is linked to dental fluorosis is widely held by many in India. There is little evidence to confirm this. ObjectiveThe study aimed to investigate the level of environmental radionuclide in order to determine any interrelationship between radionuclide and dental fluorosis in Pavagada, a fluorosis endemic area of Karnataka, India. MethodsGamma radionuclides (Th232, Ra226 and K40) were determined by high purity germanium (HPGe) gamma-ray spectrometer (Bq Kg-1) using a 50% relative efficiency p-type broad energy HPGe detector. Fluoride was estimated using fluoride Ion-selective electrode (ISE). Fluorosis was assessed using WHO diagnostic criteria. ResultsThe average mean +_SD activity concentration in soil for K40 was detected between 416.6 ± 9.3 and 769.1 ± 15.0. Th232 was estimated between 13.6 ± 0.6 and 57.6 ± 1.3; and Ra226 was found between 6.4 ± 0.4 and 21.6 ± 0.7. Similarly, the mean activity concentration detected (Bq kg-1) in granite for K40 ranged between 259.8 ± 6.9 and 1608.5 ± 26.9. The activity concentration of Th232 ranged between 26.4 ± 0.8 and 57.6 ± 1.3: and that of Ra226 was between 6.6 ± 0.3 and 21.6 ± 07. Drinking water contains 2.98 ppm of fluoride. Dental fluorosis was diagnosed as mild to moderate. ConclusionThe radionuclide activity in water, soil and granites were below the detection limit. Hence, the study revealed no association of fluorosis and radionuclide level in Pavagada, Karnataka, India. This helps resolve an ambiguity.

A Preliminary Appraisal of Radon Concentration in Groundwater from the High Background Radiation Area (HBRA) of Coastal Kerala

Abstract Parts of the coastal tracts of southern Kerala, India are among the well-known High Background Radiation Areas (HBRA) of the world, attributed to the presence of radionuclides in the monaziterich beach sand deposits. A comparative study of the radon concentrations in groundwater in the high and normal background radiation areas in the coastal tract has been taken up using analytical data of 24 ground water samples collected from tube wells of ranging in depth from 6.0 to 300.0 m. The radon concentration in the samples ranged from 0.88 to 25.80 Bq.L-1. The mean radon concentration in the study area, including those from the HBRA are within the maximum contamination levels of 300 pCi.L-1 (11.10 Bq.L-1) recommended by the United States Environmental Protection Agency except for a sample collected from Chavara. Groundwater from the high background radiation areas has significantly higher concentrations of radon ranging from 2.84 - 25.80 Bq.L-1 when compared to the normal background areas where the concentrations range from 0.86 - 7.46 Bq.L-1. Radon concentration does not show significant correlation with depth of sampled wells. The mean annual effective doses of ingestion and inhalation from water-borne radon, though comparatively higher in HBRA, are well below the average doses reported from all natural sources.

Distribution patterns of gamma radiation dose rate in the high background radiation area of Odisha, India

Absorbed dose rates in air for 20 residential areas in Odisha were measured using a vehicle-mounted NaI(Tl) scintillation spectrometer. The average values and standard deviations of absorbed dose rate in air for seaside and inland areas were 230 ± 116 nGy h−1 and 123 ± 18 nGy h−1, respectively. The annual external effective dose ranged from 0.43 to 4.59 mSv y−1 with the average value of 1.29 mSv y−1; this indicated there were wide deviations. Analysis of measured data showed that 232Th and 238U were concentrated in the seaside area.

Expectation-propagation for weak radionuclide identification at radiation portal monitors

We propose a sparsity-promoting Bayesian algorithm capable of identifying radionuclide signatures from weak sources in the presence of a high radiation background. The proposed method is relevant to radiation identification for security applications. In such scenarios, the background typically consists of terrestrial, cosmic, and cosmogenic radiation that may cause false positive responses. We evaluate the new Bayesian approach using gamma-ray data and are able to identify weapons-grade plutonium, masked by naturally-occurring radioactive material (NORM), in a measurement time of a few seconds. We demonstrate this identification capability using organic scintillators (stilbene crystals and EJ-309 liquid scintillators), which do not provide direct, high-resolution, source spectroscopic information. Compared to the EJ-309 detector, the stilbene-based detector exhibits a lower identification error, on average, owing to its better energy resolution. Organic scintillators are used within radiation portal monitors to detect gamma rays emitted from conveyances crossing ports of entry. The described method is therefore applicable to radiation portal monitors deployed in the field and could improve their threat discrimination capability by minimizing “nuisance” alarms produced either by NORM-bearing materials found in shipped cargoes, such as ceramics and fertilizers, or radionuclides in recently treated nuclear medicine patients.

Dynamics of radionuclides activity, radon exhalation rate of soil and assessment of radiological parameters in the coastal regions of Kerala, India

The activity concentration of natural radionucides such as 40K, 226Ra and 232Th and radon surface and mass exhalation rates of the soil were assessed and the related radiometric parameters have been estimated from the activities of the samples from beaches of coastal Kerala including some high background radiation areas (HBRAs). The activity concentrations of 40K, 226Ra and 232Th were estimated using NaI (Tl) gamma ray spectrometry and the radon mass and surface exhalation rate has been estimated using the ‘Can technique’ with LR-115 solid state nuclear track detectors. The estimated values indicate that the radionuclide concentrations in the study area were within the recommended limit except for Kollam district when compared with world average values. Radon exhalation rate found to vary according to grain size of the soil. Dose parameters have been evaluated in order to verify the radiological protection of the general public. The results of the present systematic investigation are presented and discussed in detail in the manuscript.

COVID-19 Tragic Pandemic: Concerns over Unintentional "Directed Accelerated Evolution" of Novel Coronavirus (SARS-CoV-2) and Introducing a Modified Treatment Method for ARDS.

Global health authorities are trying to work out the current status of the novel coronavirus (COVID-19) outbreak and explore methods to reduce the rate of its transmission to healthy individuals. In this viewpoint we provide insights concerning how health care professionals can unintentionally shift the novel coronavirus type to more drug-resistant forms. It is worth noting that viruses usually have different sensitivities to physical and chemical damaging agents such antiviral drugs, UV and heat ranging from extremely sensitive (ES) to extremely resistant (ER) based on a bell-shaped curve. Given this consideration, the widespread infection of people with such ER viruses would be a real disaster. Here, we introduce a modified treatment method for COVID-19-associated pneumonia. In this proposed method, COVID-19 patients will receive a single dose of 100, 180 or 250 mSv X-ray radiation that is less than the maximum annual radiation dose of the residents of high background radiation areas of Ramsar that is up to 260 mSv. In contrast with antiviral drugs, a single dose of either 100, 180 or 250 mSv of low LET X-rays cannot exert a significant selective pressure on the novel coronavirus (SARS-CoV-2) and hence does not lead to directed accelerated evolution of these viruses. Moreover, Low Dose Radiation (LDR) has the capacity of modulating excessive inflammatory responses, regulating lymphocyte counts, and controling bacterial co-infections in patients with COVID-19.

Functional Organization of extraterrestrial underground base on Mars

In the article relevant problems of colonization of other planets by mankind and development of extraterrestrial settlements are examined, in particular colonization of Mars and creation of Martian multifunctional base. Modern projects of leading space agencies for research and Mars colonization, shipping of equipment and the first settlers to the planet, and also projects of the first Martian habitats within the modern space technologies are discussed. In response to that natural and climatic conditions of the planet Mars which could substantially influence the formation and development of extraterrestrial multifunctional base are analyzed. Main natural and climatic factors such as high radiation background, absence of atmosphere, extreme temperature profile, low gravity, that have significant influence on formation of the Martian settlement on functional architectural and organizational levels are determined in the study. Functional model for establishment of an autonomic multifunctional base in extraterrestrial environment under the surface of the planet is proposed like the most fully satisfying the requirements for organization of extraterrestrial artificial environment for human's long-term stay considering extreme climate conditions of planet Mars and the desire to create comfortable conditions for livelihood of Martian pioneers. Basic blocks are determined and zones being parts of these blocks, which form the basis of the functional organization of extraterrestrial multifunctional complexes are detected. Possible options for functional connections between blocks and zones are analyzed.

Prototype test of a portable thyroid dose monitoring system using gamma-ray spectrometers

In case of a severe nuclear accident, radioiodine monitoring of the thyroid must be carried out for a large number of residents and emergency workers. In the present study, we developed a portable thyroid dose monitoring system consisting of two independent gamma-ray spectrometers and a radiation shield, which could be used under high background radiation conditions. Two types of prototype thyroid monitors were realized; one utilizing CdZnTe detectors for emergency workers and the other employing LaBr3(Ce) detectors for members of the public. As a result of the performance test, it was confirmed that both monitors effectively assess thyroid equivalent doses of <10 mSv during a 150 s measurement, even under high background radiation conditions.

Radiological impacts in the high-level natural radiation exposure area residents in the Ramsar, Iran

Radiological impacts due to external and internal exposure to high natural background radiation areas caused by the $${}^{226}\hbox {Ra}$$, $${}^{232} \hbox {Th}$$, and $${}^{40}\hbox {K}$$ in the soil of Ramsar, Iran, were carried out. Residual Radioactive Material Guidelines code was applied to the calculation of excess cancer risk of residence. This evaluation shows that the excess cancer risk value is the highest in 20 years’ and the lowest value in 120 years’ during the time. The results obtained from this research will be useful for risk assessment and decision making for public health protection against high-level radiation.

Correction to: A study of thoron exhalation from monazite-rich beach sands of High Background Radiation Areas of Kerala and Odisha, India

In the original article the affiliation of two authors to Homi Bhabha National Institute were not mentioned

Natural Radioactivity and Excess Lifetime Cancer Risk Associated with Soil in Kargi Area, Marsabit-Kenya

The main aim of investigating activity concentrations together with distribution of radionuclides naturally in soil from Kargi was to evaluate radiological health hazard together with environmental radioactivity. Research shows radionuclides as one source of exposure due to radiation with detrimental effects health wise for populations found in areas considered high background radiation. After collecting 117 soil samples from the area, analysis was done in order to measure their natural radioactivities due to 40K, 232Th and 226Ra radionuclides. Measurements method of gamma spectrometry employing a high purity germanium (HPGe) detector was employed basically to evaluate the radiological hazard of radioactivities. For 40K, 232Th and 226Ra, mean calculated activities were 353.19 ± 110.07, 7.98 ± 3.98 and 7.37 ± 2.60 Bq·kg -1 respectively. Mean values of absorbed and effective dose rates, external and internal hazard indices together with radium equivalent activity were 23.82 ± 6.59 nGy·h -1 and 0.14 ± 0.04 mSv·y -1, 0.12 ± 0.03 and 0.14 ± 0.04 and 45.90 ± 12.65 Bq·kg -1 respectively. Comparing with approved global values, the values were found to be below the given global limits. Evidence of involvement of metasomatic activity of the radioelements or fractionation during weathering is seen as calculations give a higher value Th/U. Excess cancer risk, calculated from the samples showed lower values as compared to global standard values hence minimal chance of getting cancer disease. The area is safe from cancer causing radionuclides.

Assessment of natural radioactivity levels in soil sample from Botteng Utara Village, Mamuju Regency Indonesia

High background radiation areas usually are correlated to the high concentration of primordial radionuclides activity from Uranium/Thorium series and 40K. This paper reported the natural radioactivity level in soil sample was taken from Botteng Utara village area. The activity of primordial radionuclide such as 226Ra, 232Th and 40K were investigated from the soil by gamma spectrometry. In order to evaluate the radioactivity levels of the area, Radium equivalent activity (Raeq), the absorb dose rate (D), the annual effective dose rate (E), the external hazard index (Hex), and internal hazard index (Hin) were calculated and compared with the internationally approved value. The concentration of 226Ra, 232Th and 40K measured by gamma spectrometry are lies in the range 268.90 to 2921.17, 993.07 to 3153.81, and 115.72 to 438.26 Bq.kg−1respectively. The average and maximum annual effective dose received by Botteng Utara resident from terrestrial gamma rays are 10.40 and 18.62 mSv y−1, which is the maximum received by resident of Tande-Tande hamlets. This present work clarify that Botteng Utara is an area with high background radiation exposure from primordial radionuclides activity.