Soil Radon Concentration Research Articles

Laboratory study on the relationship between the vertical distribution of radon concentration in soil and the exhalation rate of radon from the soil surface

Laboratory study on the relationship between the vertical distribution of radon concentration in soil and the exhalation rate of radon from the soil surface

Development of a High-Resolution Indoor Radon Map Using a New Machine Learning-Based Probabilistic Model and German Radon Survey Data.

Radon is a carcinogenic, radioactive gas that can accumulate indoors and is undetected by human senses. Therefore, accurate knowledge of indoor radon concentration is crucial for assessing radon-related health effects or identifying radon-prone areas. Indoor radon concentration at the national scale is usually estimated on the basis of extensive measurement campaigns. However, characteristics of the sampled households often differ from the characteristics of the target population owing to the large number of relevant factors that control the indoor radon concentration, such as the availability of geogenic radon or floor level. Furthermore, the sample size usually does not allow estimation with high spatial resolution. We propose a model-based approach that allows a more realistic estimation of indoor radon distribution with a higher spatial resolution than a purely data-based approach. A multistage modeling approach was used by applying a quantile regression forest that uses environmental and building data as predictors to estimate the probability distribution function of indoor radon for each floor level of each residential building in Germany. Based on the estimated probability distribution function, a probabilistic Monte Carlo sampling technique was applied, enabling the combination and population weighting of floor-level predictions. In this way, the uncertainty of the individual predictions is effectively propagated into the estimate of variability at the aggregated level. The results show an approximate lognormal distribution of indoor radon in dwellings in Germany with an arithmetic mean of , a geometric mean of , and a 95th percentile of . The exceedance probabilities for 100 and are 12.5% (10.5 million people affected) and 2.2% (1.9 million people affected), respectively. In large cities, individual indoor radon concentration is generally estimated to be lower than in rural areas, which is due to the different distribution of the population on floor levels. The advantages of our approach are that is yields a) an accurate estimation of indoor radon concentration even if the survey is not fully representative with respect to floor level and radon concentration in soil, and b) an estimate of the indoor radon distribution with a much higher spatial resolution than basic descriptive statistics. https://doi.org/10.1289/EHP14171.

STL decomposition analysis for anomaly detection in soil radon and thoron concentrations along Chite fault in Aizawl

STL decomposition analysis for anomaly detection in soil radon and thoron concentrations along Chite fault in Aizawl

Investigation on radon levels in soil and water associated with Mount Tampomas geothermal activity in Indonesia

ObjectiveTo investigate radon emanation in geothermal manifestations around Mount Tampomas, West Java, Indonesia, and assess radon concentrations in soil and water samples. MethodsRadon measurements were conducted using the Durridge Rad7 instrument, supplemented with a soil gas probe for in-situ soil radon measurements at a depth of 80 ​cm. In-situ water radon measurements were performed using the Rad Aqua instrument, while radon measurements for hot water samples were conducted separately. Radon measurements for hot water samples were corrected for decay using a radon decay correction factor. ResultsThe analysis of radon measurements revealed a wide range of concentrations in soil and water samples. Soil radon concentrations ranged from 15 Bq/m³ to 4,660 Bq/m³, with localized hotspots exhibiting exceptionally high concentrations. Water radon measurements showed elevated levels, ranging from 0.2 Bq/L to 13.4 Bq/L in-situ, particularly in hot springs. In collected water samples, radon concentrations ranged from 1 Bq/L to 6 Bq/L. These combined results highlight significant variability in radon levels across different water sources influenced by geothermal activity. ConclusionsThese findings indicate active emanation processes influenced by geological factors and underscore the role of subsurface geology and aquifer characteristics in radon transport mechanisms. The presence of localized radon hotspots suggests the need for comprehensive monitoring and proactive management strategies to mitigate environmental and public health risks associated with radon exposure.

Assessment of Indoor and Soil-Gas Radon Concentration of a Quarry Site in Eiyekorin, Kwara State

The toxic health effect of human exposure to radon gas which is radioactive in nature has attracted extensive research attention worldwide. Since direct experiments on the effect of earthquakes on radon release are difficult to conduct, a possible alternative is to use man-made explosions as an earthquake surrogate and investigate the corresponding effect on radon concentration. This study aims at investigating the soil-gas radon concentration in an active quarry site and areas outside the quarry, and the infiltration of the gas into the indoor environment was measured in order to access the occupational exposure risk. Soil gas radon concentration was taken at 30 random locations within the quarry and areas outside the quarry using RAD7, likewise 10 indoor radon gas in offices and homes were measured using an active radon detector manufactured by Durridge Incorporation in USA and comparative analysis of the difference between the two locations were done. The mean of the soil-gas radon concentration in the quarry site is 24968.84 ± 6913.204Bq/m3 while that of outside the quarry is 9664.67 ± 4992.86 Bq/m3. The result shows higher values of radon-gas concentration in the quarry site compared with area outside the quarry and when compared to the International Commission on Radiation Protection (ICRP) suggested value of radon concentration in soil and sediment, which is in the range of 0.4 to 40 KBqm-3, result shows that most location within the study area are higher than these limits. Also, the radon in air indoor and outdoor was taken at the offices located within the quarry and occupational exposure risk was carried out. The average of radon in air indoor and outdoor was found to be 31.12 Bqm–3 and 10.12 Bqm–3 respectively with higher values found indoor. However, the values are found to be below the recommended value of 300 Bq/m3 by ICRP publication for homes and workplaces.

Effect of Seasonal Variation and Soil Parameters on Soil-Gas Radon Concentration in Ogbomoso, South Western Nigeria

Radon 222Rn, an inert natural radioactive gas, a daughter product in the 238U natural decay series, a source of alpha radiation. It accounts for about 55% of the total radiation from natural sources. Radon is known for its substantial variations in concentration due to both seasonal changes and variations in soil parameters. Soil, fractures in rocks and water are the main source of radon and they are the routes through which individual is exposed to it, in which this study is aimed at examining the effects of seasonal variation, soil parameters, on soil radon concentration. A total of hundred (100) in-situ soil radon measurements were carried out for both seasons (wet and dry) in Ogbomoso using an active electronic device RAD 7. Soil parameters were measured using a 4-in-1 digital metre. The obtained experimental data were subjected to a statistical tool (SPSS) Version 23, with statistical significance set at p < 0.01. The result showed that the effect of seasonal variation on soil-gas radon concentration was discovered to be maximum during the dry season with the radon concentration of 1900.01 Bq/m3 and minimum during the wet season with the radon concentration of 711.81 Bq/m3.The mean value of radon in soil-gas was found to be 553.48 Bq/m3 and 1366.34 Bq/m3 for wet and dry season respectively. Soil parameters considered in this work have notable influence on soil gas radon concentration in both seasons. Thus, providing valuable insight into the dynamics of radon migration in the soil. The results will help to develop effective mitigation strategies by policies makers and reducing the risk of radon related lung cancer in the study area.

Determination Of Heavy Metals and Radon Concentration in Soil and Water Samples from Wadi-B Jere Oil Exploration Sites in Maiduguri, Northeast Nigeria

Radon gas and heavy metals are two significant risk factors that can cause lung cancer. Wadi B, a locality in Jere local government of Borno state, is an area where oil exploration is underway. There is a potential health risk of contamination of the drinking water and soil samples in the area. To investigate radon concentration and heavy metal contamination, several samples of water from wells and boreholes, as well as soil samples, were collected for analysis. The analysis was conducted using liquid scintillation (LSC) and atomic absorption spectrometry. The result of radioactivity analysis using LSC shows that water samples have varying levels of radon concentration ranging from 17.77 Bql-1 to 22.50Bql-1 which exceeded the maximum contaminant levels of 11.1Bq/L set by the USEPA 1999 and the world average value of 10Bq/L set by the World Health Organisation (WHO 2004). The mean annual effective cancer risk of radon intake varied across sampling points, ranging from 0.164, 0.246, 0.287 to 0.130, 0.218, and 0.227 for adults, children, and infants, respectively, with mean values of 0.146, 0.219, and 0.255. The mean values of excess lifetime cancer risk (ELCR) associated with radon inhalation and ingestion for adults, children, and infants were 0.0005110, 0.0007660, and 0.0008930, respectively. Moreover, elevated conductivity and total dissolved solids in water samples suggest potential contamination, exceeding the recommended limits set by the World Health Organization. On the other hand, Heavy metals analysis shows a mean value of ELCR 0.125009 for adults and 0.000063 for infants. Results showed that heavy metal concentrations in soil samples exceeded permissible limits for all metals except chromium and lead, with the order of concentration being Cr < Cd < Pb < Cu < Zn. These findings underscore the need for ongoing monitoring and remediation efforts to mitigate environmental and health risks in Wadi B

A study of some research work on soil radon concentration and ionospheric total electron content as earthquake precursors

A study of some research work on soil radon concentration and ionospheric total electron content as earthquake precursors

Analysis of Indoor Radon Concentration Levels and Influencing Factors in Kunshan

Radon is a natural radioactive gas widely existing, in order to study the indoor radon level and influencing factors in Kunshan City, the indoor radon concentration of three buildings was analyzed. It was found that all of them met the indoor radon concentration limit specified in the national standard, and the indoor radon concentration was mainly related to soil radon concentration, indoor ventilation and climate. Indoor radon can be controlled from the following points: (1) While building a new building, test the radon concentration in the soil and try to avoid areas with high concentrations. (2) Pay attention to daily window ventilation, especially in cold weather and poor air circulation in winter. (3) Find and prevent indoor radon sources, building materials will also release a certain amount of radon, and interior decoration materials must be selected to meet national standards.

Radon Hazard of the Zhurinsky Fault for the Population in the Kuznetsk Coal Basin: Primary Results

The aim of this study is the primary assessment of radon hazard of the Zhurinsky fault of the Kuznetsk coal basin, in the territory of the Salair–Altai–Irtysh fold. Soil radon content, radon flux densities, their spatial characteristics and correlations with each other and with other factors were evaluated. We found that soil radon concentration varies within the range of 3599 to 14,413 Bq/m3 (mean value 8766 ± 569.8 Bq/m3), and radon flux density ranges from 23 to 147 mBq·m−2·s−1 with a mean value of 67.19 ± 1.31 mBq·m−2·s−1. A correlation with air temperature, pressure and humidity was found, which decreases with the depth of the measurements. All studied parameters in space are clustered (p ≤ 0.1). At the same time, the whole studied area in the vicinity of the tectonic disturbance should be classified as radon-hazardous, and residential structures located within its boundaries as potentially hazardous. Our study contributes to understanding the radon hazard of crustal faults.

Exploring soil radon (Rn) concentrations and their connection to geological and meteorological factors.

The relationship between soil radon and meteorological parameters in a region can provide insight into natural processes occurring between the lithosphere and the atmosphere. Understanding this relationship can help models establish more realistic results, rather than depending on theoretical consequences. Radon variation can be complicated to model due to the various physical variables which can affect it, posing a limitation in atmospheric studies. To predict Rn variation from meteorological parameters, a hybrid mod el called multiANN, which is a combination of multi-regression and artificial neural network (ANN) models, is established. The model was trained with 70% of the data and tested on the remaining 30%, and its robustness was tested using the Monte-Carlo method. The regions with low performance are identified and possibly related to seismic events. This model can be a good candidate for predicting Rn concentrations from meteorological parameters and establishing the lower boundary conditions in seismo-ionospheric coupling models.

Assessment of Radiological Risks due to Indoor Radon, Thoron and Progeny, and Soil Gas Radon in Thorium-Bearing Areas of the Centre and South Regions of Cameroon

Indoor radon, thoron and thoron progeny concentrations, along with the equilibrium factor for thoron progeny and soil gas radon concentrations, have been measured to assess radiological risks in the centre and south regions of Cameroon. Indoor radon and thoron concentrations were estimated using radon–thoron discriminative detectors (RADUET), while thoron progeny monitors measured the equilibrium equivalent thoron concentration (EETC). Radon concentrations in the soil were determined using a MARKUS 10 detector. It was found that radon, thoron and thoron progeny concentrations range between 19 and 62 Bq m−3, 10 and 394 Bq m−3 and 0.05 and 21.8 Bq m−3, with geometric means of 32 Bq m−3, 98 Bq m−3 and 4.9 Bq m−3, respectively. The thoron equilibrium factor ranges between 0.007 and 0.24, with an arithmetic mean of 0.06 ± 0.03; this is higher than the world average value of 0.02 provided by the United Nations Scientific Commission on the Effects of Atomic Radiation(UNSCEAR, New York, USA). The level of the soil radon concentration ranges from 4.8 to 57.3 kBq m−3, with a geometric mean of 12.1 kBq m−3 at a depth of 0.7 m. Of the sampling points, 66% fall within normal radon risk areas, and 3% of the sampling areas are high radon risk areas exceeding 50 kBq m−3. The annual effective dose was found to be 0.03 ± 0.01 mSv for radon, 0.08 ± 0.05 mSv for thoron, 0.63 ± 0.12 mSv for radon progeny and 1.40 ± 0.84 mSv for thoron progeny. The total dose is estimated to be 2.14 mSv y−1. The mean estimated indoor excess lifetime cancer risk values due to radon, thoron, radon progeny and thoron progeny are 0.12 × 10−3, 0.31 × 10−3, 2.51 × 10−3 and 5.58 × 10−3, respectively. Thoron progeny contributed 60% to the effective dose. Thus, thoron progeny cannot be neglected in dose assessments, in order to avoid biased results in radio-epidemiological studies.

High radon levels and adverse environmental conditions in using RAD7.

Good response was observed in simultaneously using six RAD7 detectors at high radon concentrations, temperatures and relative humidity conditions. RAD7 detectors were tested in laboratory using radon chambers from 13 up to 59.8kBqm-3, statistical analysis allows to distinct between counting errors and radon variation. RAD7 detectors were exposure to extreme environmental conditions at uranium flat mine. High radon concentration in soil from a confined uranium mineral was 274.3kBqm-3 at 44°C temperature and 20% relative humidity. Inside uranium mine radon increased from 1.0 up to 88.5kBqm-3.

Measurement of soil radon concentration in Balikesir and examination of its effects on health

Most of the natural radiation originates from radon, approximately 55%. This radiation occurs because of the radioactive decay of natural uranium found in rocks, soil and water. Because radon is in gaseous form, it can easily leak into living spaces and accumulate. Inhalation of radon and radon decay products is a significant health risk factor. Considering the high mortality rate of lung cancer in our country, inhalation of high radon concentrations has been associated with the risk of lung cancer. Accurate measurement of radon levels is especially important for dose assessment of radon exposure. In this study, it was aimed to determine the natural radon concentrations in Balikesir province and districts using the active method by soil measurement using the AlphaGUARD portable radon detector, and to perform radiological risk analyzes by determining the radon levels of the region covering Balikesir Province by measuring the natural radiation emitted from the soil. As a result of the measurements, the lowest radon concentration amount was measured in Akcay district of Balikesir province and its average value is 17.65 ± 2.71 kBq/m3. The humidity in the environment is 72.34%, the average pressure is 1013.61 hPa and the average temperature is 33.02 °C. The highest radon concentration amount was measured in Havran district of Balikesir province and its average value is 66.71 ± 2.52 kBq/m3. The humidity in the environment is 58.61%, the average pressure is 1007.91 hPa and the average temperature is 31.80 °C.

Mapping in a radon-prone area in Adamawa region, Cameroon, by measurement of radon activity concentration in soil.

The radon-prone area of the Adamawa region in Cameroon is characterized by high natural radiation background resulting from the high concentrations of radium-226, thorium-232, and indoor radon. To produce a radon-risk map, radon measurements in soil were carried out in the city of Ngaoundere. The radon activity concentration in soil gas ranged from 256 to 166kBqm-3 with a mean of 80kBqm-3 and a standard deviation of 38kBqm-3. The area is mostly classified as high risk (80%) according to the Swedish classification, and 20% as medium risk. A low-risk area was not observed. Granite-like geology sites were characterized by higher radon concentration. A ratio of about 295:1 was obtained for soil radon gas to indoor radon concentrations, with a positive correlation (R = 0.40), and a transfer factor of 3 per mil. These results demonstrate that in situ measurements of radon concentration in soil can provide accurate information on the level of indoor radon concentrations. Geostatistical and deterministic interpolation techniques have been used to obtain a radon map by comparing the suitability of ordinary kriging and inverse-distance-weighted (IDW) interpolation methods. It turned out that there is not much difference in the prediction errors of the two techniques (Root Mean Square Error = 34.4 for ordinary kriging and 34.3 for IDW). It is concluded that both methods give acceptable results. In situ measurements and geostatistical analysis allow assessment of expected indoor radon exposure in a given area at reduced costs and time required. However, for the investigated area, more research is needed to produce reliable radon-risk maps.

Distribution of Radionuclides in the Surface Covering of the Barun Uranium Mining Area in Erlian Basin, Inner Mongolia

In order to identify the distribution pattern of radionuclides in the surface soil in the area of a sandstone-type uranium deposit, and to explore its spatial relationship with the location of the orebody, soil radon measurements and ground gamma-ray spectroscopy were carried out in the Barun study area, and soil properties were analyzed. The results show that the soil radon concentrations exhibited a bimodal feature, while the uranium content showed a decreasing trend along the tendency direction of the orebody. In the ground projection area of the orebody, radon concentration showed a positive correlation with uranium content, with both showing relatively low values. Combined with the results of field geological observation and soil property analysis, it is believed that the relatively low radon concentration and uranium content above the orebody is related to the soil being mainly sandy soil. Relatively high uranium values are distributed within approximately 1.5 km north of the northern boundary of the orebody and near the southern boundary of the orebody. High-value radon anomalies occur within about 2 km north of the northern boundary of the orebody and within about 1.3 km south of the southern boundary of the orebody.

Application of airborne geophysical survey data in a logistic regression model to improve the predictive power of geogenic radon maps. A case study in Castleisland, County Kerry, Ireland

In this study, a novel methodology was investigated to improve the spatial resolution and predictive power of geogenic radon maps. The data inputs comprise indoor radon measurements and seven geogenic factors including geological data (i.e. bedrock and Quaternary geology, aquifer type and soil permeability) and airborne geophysical parameters (i.e. magnetic field strength, gamma-ray radiation and electromagnetic resistivity). The methodology was tested in Castleisland southwest Ireland, a radon-prone area identified based on the results of previous indoor radon surveys. The developed model was capable of justifying almost 75 % of the variation in geogenic radon potential. It was found that the attributes with the greatest statistical significance were equivalent uranium content (EqU) and soil permeability. A new radon potential map was produced at a higher spatial resolution compared with the original map, which did not include geophysical parameter data. In the final step, the activity of radon in soil gas was measured at 87 sites, and the correlation between the observed soil gas radon and geophysical properties was evaluated. The results indicate that any model using only geophysical data cannot accurately predict soil radon activity and that geological information should be integrated to achieve a successful prediction model. Furthermore, we found that EqU is a better indicator for predicting indoor radon potential than the measured soil radon concentrations.

The temporal variation of radon concentration at different depths of soil: A case study in Beijing

Variations in soil radon concentrations are a potential precursor of earthquake and volcanic events. However, the unclear migration and variation mechanisms of radon concentrations in soil still limit its effective application. To elucidate the temporal variation and its possible influence factors on radon concentrations at different soil depths, a case study was performed at a suburban site in Beijing. A long-term continuous measurement system consisting of ten radon-in-soil monitors at depths from 0.1 to 5.0 m and other meteorological sensors was employed. The monitoring was carried out from January 8th to July 29th, 2022, covering 3445 h in total. Radon concentrations generally increased with soil depth. Diurnal variation of soil radon concentrations at depths of 1.2 and 1.6 m in winter and spring was observed, and a negative correlation between the soil radon concentration and the residual air pressure was found. This finding indicates a possible air exchange channel between the soil and the atmosphere at the study site. In addition, the soil radon concentration at 4.0 m depth was unexpectedly lower than that of neighboring depths and was steady throughout the measurement period. This is attributed to a possible clay layer in the soil structure at 4.0 m depth. The results of this field study indicate that the complexity of temporal variation of soil radon concentrations should be considered for its application in predicting earthquake and volcanic events.

IRREGULARITIES THE RELATIONSHIP OF VARIATIONS IN THE VOLUME ACTIVITY OF RADON AND ATMOSPHERIC PRESSURE DURING SEISMIC ACTIVITY (ON THE EXAMPLE OF THE BAIKAL REGION)

A comparison was made of temporal variations in atmospheric pressure and soil radon concentration measured in loose sediments at three monitoring stations in the Baikal region for the period of manifestation of three fairly strong earthquakes – Bystrinsky (21.09.2020, K = 14.6), Kudarinsky (09.12.2020, K = 14.0) and Khubsugulsky (11.01.2021, K = 16.0). It has been established that the release of radon is controlled in the region by variations of atmospheric pressure. Irregularities of this dependence, first identified in the course of a formalized statistical analysis, occur for each of the studied seismic activations. They are connected with the process of preparing an earthquake, which opens up real opportunities for developing an emanation approach to medium-term forecasting.

Levels of Radon in Soils of Dodoma City, Central Tanzania

Purpose: Humans receive radiation doses exceeding fifty percent (50%) of the total dose from natural sources as a result of inhaling radon and thoron gases and their daughters. Radon occurs naturally in soils and can diffuse into indoor environments leading to adverse health effects for inhabitants. In this study, measurement of levels of radon gas in soils was performed with the purpose of categorizing areas and highlighting the likelihood of high levels of radon in indoor environments.
 Design/Methodology/ Approach: The study targeted the environs of Dodoma where the rapid expansion of human settlements is ongoing or anticipated. For easy access and convenience, the study was conducted in areas located along main roads leading to the nearby towns/cities. Sampling was done by inserting the drilling rod to a depth of approximately one meter (1 m) below ground level with the aid of a heavy hammer. The alpha pump was used to suck the soil gas from the ground through a metallic tube (the capillary probe) and pressed it into the ionization chamber of the measuring instrument (AlphaGUARD). Radon concentration was read directly from the instrument’s display.
 Findings: It was found that radon concentrations in soil vary from 18.8 to 233.5 kBq.m-3. Based on the radon risk criterion, surveyed areas range from normal to high radon risk categories.
 Research Limitation/Implication: The study only covered a limited area in Dodoma City, and therefore the results may not be representative of the entire city or even the surrounding regions.
 Practical Implications: This study is useful in categorizing building areas based on radon risk criterion with the purpose of reducing possibilities of radon-related health risks; mainly lung cancer to the population.
 Social Implications: Radon is a proven cause of lung cancer in humans. Therefore, knowledge of radon levels in the study area will help in setting the mitigation measures necessary for public health protection.
 Originality / Value/ Novelty: The study demonstrates an approach for estimating radon levels in soils which is beneficial to current and future researchers, environmentalists and regulators, among others.