Radon Activity Research Articles

Health Effects of Natural Environmental Radiation during Burning Season in Chiang Mai, Thailand.

This paper presents the first measurement of the investigation of the health impacts of indoor radon exposure and external dose from terrestrial radiation in Chiang Mai province during the dry season burning between 2018 and 2020. Indoor radon activity concentrations were carried out using a total of 220 RADUET detectors in 45 dwellings of Chiang Mai (7 districts) during burning and non-burning seasons. Results show that indoor radon activity concentration during the burning season (63 ± 33 Bq/m3) was significantly higher (p < 0.001) compared to the non-burning season (46 ± 19 Bq/m3), with an average annual value of 55 ± 28 Bq/m3. All values of indoor radon activity concentration were greater than the national (16 Bq/m3) and worldwide (39 Bq/m3) average values. In addition, the external dose from terrestrial radiation was measured using a car-borne survey during the burning season in 2018. The average absorbed rate in the air was 66 nGy/h, which is higher than the worldwide average value of 59 nGy/h. This might be due to the high activity concentrations of 238U and 323Th in the study area. With regards to the health risk assessment, the effective dose due to indoor radon exposure, external (outdoor) effective dose, and total annual effective dose were 1.6, 0.08, and 1.68 mSv/y, respectively. The total annual effective dose is higher than the worldwide average of 1.15 mSv/y. The excess lifetime cancer risk and radon-induced lung cancer risk during the burning season were 0.67% and 28.44 per million persons per year, respectively. Our results substantiate that indoor radon and natural radioactive elements in the air during the burning season are important contributors to the development of lung cancer.

Preliminary studies on soil radon activity at geothermal hotspot of Bakreswar-Tantloi

Bakreswar-Tantloi region of India, besides being a geothermally active region, also harbours a high amount of Radon in soil-gas and groundwater of the region. Measurement of Radon-content across the region is an active area of research aimed to properly understand the geothermal potential of the region, the study of local geology and to determine the risks of Radon exposure in the area. In an aim to evaluate the Radon potential of this important geothermal hub, we have done a pilot study on the region by doing spot measurements of Soil-Radon activity in 41 specific geographic locations spread out across the region of interest which will act as groundwork for further in-depth analysis. The measurements showed that Radon activity varies widely in the region with the Radon activity ranging from 1 to 52 across the measured locations. Mean Radon activity across the measured locations was found to be 16 with standard deviation of the sample set of 14 Seven locations recorded Radon activity to be greater than standard deviation from average while four locations recorded Radon activity greater than twice the standard deviation from average.

Radon daughter's radioactivity levels in the Arabian Sea as indicators of airmass mixing

Measurements on radon daughter's activities in the Arabian Sea were carried out during the period 19 May to 9 July 1973, under the joint Indo-USSR MONEX-73 project. The data were collected on board the ships of the Indian Navy cruising between 19°N- 21°N, within longitudes 60°E- 73°E and the two USSR vessels Okean and Priliv cruising between latitudes 0°-10°N and 10°N-18°N, respectively. The results show that there is a significant increase in radon daughter's activity at about 19°N-21°N, the average level being of the order of about 8 pci/m3 as compared to 1-2 pci/n13 at lower latitudes. This is explained, on the basis of synoptic charts and available sounding data, as being due to the wind and pressure pattern prevailing during the monsoon months which result in the transport of continental -air from Arabia and Pakistan and its mixing with the maritime monsoon airmass of southern hemispheric origin. The significant increase .in radon activity on some days of the cruise was mainly due to the existence of disturbances like depressions, cyclonic storms, etc, over the north Arabian Sea, or due to the passage of Western disturbances at a relatively lower latitudes (along approximately 25°N) and their associated circulation patterns. These phenomena favour significant transport of continental air from the north a~ west. The mixing of this continental airmass with the airmass of low radon concentrations results in increasing the average randon levels from 1 to 8 pci/m3.

Multi-level continuous monitoring of indoor radon activity

We present the results of an experiment taking place inside the geophysical museum of Rocca di Papa (Rome, Italy), where the high radon levels detected might pose a risk to the health of workers and of the public audience. As a first step towards the mitigation of potential exposure risk, four active sensors were installed at different floors of the building, in order to continuously monitor not only radon exhalation from the soil but also its transport from the ground up to elevated floors. Collecting more than three years of data of radon concentration enables us to identify fluctuations over both short and seasonal scales and to elucidate the relation between radon variations and changes of internal temperature and relative humidity. The analysis of such dataset reveals how the healthiness of indoor environments in terms of radon concentration is controlled by a number of factors, including the environmental conditions and the use of heating and ventilation systems. Finally, the continuous radon monitoring at different levels of the building provides a unique chance to trace the vertical radon diffusion, allowing to make a first-order estimate of upward radon velocity.

Radiological Hazard Related with Natural Radioactivity in Natural Gas Transportation—A Case Study from Poland

Activity concentration of 210Pb in black powder and gamma radiation dose rate related to natural gas transportation were discussed. As part of the research, the content of radiolead (210Pb) in black powder, spent filter containers, radon (222Rn) activity concentration in natural gas and gamma radiation dose were measured around selected points of natural gas transportation infrastructure in Poland. The content of some heavy metals was also analyzed. The average concentrations of 222Rn and 210Pb ranged from 30 to 1400 Bq/m3 and from around 450 to 16,000 Bq/kg, respectively. The external exposure to gamma radiation was low; the gamma radiation dose rate was at the level of background radiation or slightly exceeded it. The research demonstrated that the content of 210Pb in black powder is strongly related to radon concentration in natural gas, the volumetric flow rate of the transported natural gas and solid fraction content. Some black powder samples should be classified based on 210Pb content as low-radioactive waste.

Soil gas radon concentration measurement in estimating the geogenic radon potential in Abeokuta, Southwest Nigeria

The soil gas in-situ radon-222 concentration was measured at 28 locations in Abeokuta, Nigeria using a RAD7 solid-state detector. The measurement sites were chosen based on the extent of the 6 geological formations chosen in a cell, with a spatial sample of at least 3 km between them. The measuring sites' geographical coordinates were established using the Global Positioning System compass. The hydraulic conductivity measuring technique was also used to determine the soil-air permeability for the soil samples collected at the various locations. The measured soil gas radon concentration and the soil-air permeability were used to estimate the geogenic radon potential. The soil gas radon activity ranged from (1004–19250) Bq/m3. The soil-air permeability ranged from (9.7 × 10−13 to 2.64 × 10−11) m2. The Geogenic Radon Potential ranged from 0.5 to 33 whereby 7.69% of the study area had a medium GRP value (10<GRP<35) while 92.31% had a low GRP value (GRP<10) as based on Classification of GRP according to Neznal. Therefore, the GRPs for Abeokuta are low compared with the level where remedial action is needed.

Experimental Studies to Test a Predictive Indoor Radon Model.

The accumulation of the radioactive gas radon in closed environments, such as dwellings, is the result of a quite complex set of processes related to the contribution of different sources. As it undergoes different physical mechanisms, all occurring at the same time, models describing the general dynamic turns out to be difficult to apply because of the dependence on many parameters not easy to measure or calculate. In this context, the authors developed, in a previous work, a simplified approach based on the combination of a physics-mathematical model and on-site experimental measurements. Three experimental studies were performed in order to preliminarily test the goodness of the model to simulate indoor radon concentrations in closed environments. In this paper, an application on a new experimental site was realized in order to evaluate the adaptability of the model to different house typologies and environmental contexts. Radon activity measurements were performed using a portable radon detector and results, showing again good performance of the model. Results are discussed and future efforts are outlined for the refining and implementation of the model into software.

Low-Level Radon Activity Concentration-A MetroRADON International Intercomparison.

An international comparison of continuous monitors measuring radon activity concentration was performed to validate the traceability of the European radon calibration facilities. It was carried out by comparing the secondary standards used by these previous facilities, ranging from 100 Bq·m−3 to 300 Bq·m−3. Secondary standards were individually compared to a secondary reference device previously calibrated in a reference radon atmosphere traceable to a primary standard. The intercomparison was organized by the National Institute for Nuclear, Chemical, and Biological Protection (SUJCHBO) in the period from October 2019 to April 2020 within the European Metrology Program for Innovation and Research (EMPIR), JRP-Contract 16ENV10 MetroRADON. Eight European laboratories participated in this study. The results of the experiment are presented and discussed.

Radioaktivní prameny v Praze-Čimicích

Groundwater inflows showing notable natural radioactivity have been found at the northern end of the Holešovice cable tunnel close to the Čimice Grove. This groundwater originates from the Barrandian Neoproterozoic slates of the Blovice accretionary complex, Belt I (Šárka-Zbiroh Belt) at depths approximately 100 meters below the surface, occurring along 50 meter profile of the cable tunnel. Water springs are dispersed in the spring area, with the total discharge of 2 L/s. Groundwater is cold (T ~ 11.1 – 12.3 °C), neutral (pH ~ 6 – 7.48), suboxic to oxic (Eh (ORPH) ~ 177 up to 418 mV), of a hydrochemical type Ca-Mg-HCO3, total mineralization being around 702 mg/L. Radon activity (222Rn) varies between 415 and 1195 Bq/L and radium activity (226Ra) ranges between 0.18 and 5.3 Bq/L. Activities of Rn and Ra are relatively high. Currently, this is the most radioactive water within Prague agglomeration. This water is relatively aggressive as well, causing damage to the concrete lining of the cable tunnel and also allowing formation of calcite precipitates with an increased radium (226Ra) activity.

The Inskie Springs: New Insights into Low-Radon Waters

Abstract —In August 2019, four descending (gravity) springs in the Inya River valley were sampled during the field works conducted within the study of low-radon waters of the Novosibirsk urban agglomeration in the area lying away from known granite massifs. Laboratory analyses have revealed enhanced radon activity concentrations (from 5 to 149 Bq/dm3). It has been established that these waters are fresh, of HCO3 Mg–Ca chemical composition, and have a TDS value of 413 to 548 mg/dm3 and a silicon content of 4.1–8.6 mg/dm3. They are characterized by neutral to slightly alkaline pH (7.1–8.4) and oxidizing geochemical conditions with Eh from +205.3 to +231.8 mV and O2 dissolv. = 6.24–12.26 mg/dm3. The revealed predominance of SO42– over Cl– concentrations in the waters of the study area was probably due to the presence of sulfides in the water-bearing sediments, in particular, pyrite in the surface sediments. More than tenfold proportional excess of Ca concentrations over Si in the Inskie spring waters indicates the predominantly carbonate composition of the water-bearing sediments. The gross α-activity of waters is 3–4 mBq/dm3, and gross β-activity is 11–15 mBq/dm3. Natural radionuclides are found in the spring waters within the following limits (mg/dm3): 238U, from 2.83 ∙ 10–3 to 4.13 ∙ 10–3; 232Th, from 2.39 ∙ 10–6 to 1.16 ∙ 10–5, and 226Ra, from 3.83 ∙ 10–10 to 4.93 ∙ 10–10. The value of the 232Th/238U ratio for the waters ranges from 5.79 ∙ 10–4 to 3.61 ∙ 10–3, as a result of the oxidative geochemical migration-arresting capability of thorium. The uranium isotope ratio (γ) 234U/238U varies from 2.6 to 3.2 for the waters, with the uranium isotope activity determined as 117–124 mBq/dm3 for 234U and 38–48 mBq/dm3 for 238U. This indicates shallow circulation of the studied waters as compared with those of the Svyatoi spring in Verkh-Tula Village, for which γ = 1.3; the 234U activity, 147 mBq/dm3; and the 238U activity, 115 mBq/dm3. By isotopic composition, the origin of the spring waters is assigned to the infiltration type, and they are characterized by relatively narrow distribution of δ18O (from –17.5 to –16.7‰) and δD (from –128.4 to –126.2‰) values. The δ13CDIC values are from –10.3 and –10.9‰ in springs 3 and 2 and become lighter (–11.2 and –12.1‰) in springs 1 and 4, respectively. This is due to significant participation of surface waters in the recharge mechanism of springs 1 and 4, which is also consistent with the δ18O and δD data and 14C dating. The estimated age of water-dissolved carbon is 1478 ± 81 years for the waters of spring 3 (the oldest), while it is found to be only 651 ± 53 years for spring 4 and is estimated as modern for spring 1. The reported decline in the age of water-dissolved carbon down to recent age is indicative of increased contribution of surface water to the spring recharge area. The C and O isotope compositions of calcite of the host aquifer rocks are characterized by close values for most of the samples: δ13С varies within narrow limits (from –3.1 to –2.7‰), and δ18О varies from 17.2 to 18.4‰. The isotopic composition becoming lighter for carbon (up to –11.0‰) and oxygen (up to 13.9‰) was noted for weathered schist samples. Results of the carbon isotope analysis of rock samples, their organic component, and water indicate an active isotopic exchange in the water–rock–organic matter system.

ARMAX Forecast Model for Estimating the Annual radon Activity Concentration in Confined Environment by Short Measurements Performed by Active Detectors.

This work aims to implement a forecast model that, combined with the use of active instrumentation for a rather limited time, and with the knowledge of a set of data referring to the environmental parameters of the place to be monitored, can estimate the concentration of indoor radon activity for longer time periods. This model has been built through the MATLAB program, exploiting the theories of time series and, in particular, ARMAX models, to reproduce the variation in the concentration of radon activity. The model validation has been carried out by comparing real vs. simulated values. In addition, analytic treatment of input data, such as temperature, pressure, and relative humidity, can reduce the influence of sudden transients allowing for better stability of the model. The final goal is to estimate the annual radon activity concentration on the basis of spot measurements carried out by active instrumentation, such to avoid the need to measure for an entire calendar year by the use of passive detectors. The first experimental results obtained in conjunction with active radon measurement demonstrates the applicability of the method not only for forecasting future average concentrations, but also for optimizing remedial actions.

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

Understanding radon (222Rn) transport in one and multi-layer soils using analytical and finite element modeling

This study investigates the transport of Radon (222Rn) which is the second leading cause of lung cancer after smoking. A new and optimized finite element numerical model (FERM-1D, Finite Element Radon Modeling in one dimension) of Radon transport is developed and tested with analytical models’ solutions under different conditions in addition to verification against field data for soils with multi-layer behavior. The interaction between the Radon 222Rn different mechanisms such as diffusion, advection, decay and generation is explained in details. Transport numbers are proposed that determine conditions under which each mechanism of diffusion, advection, decay and generation dominates. A transport similarity concept is presented in which different combination of mechanisms and model parameters can produce the same Radon activity concentration profile. Moreover, new prospective is presented to modeling soils with multi-layer Radon transport characteristics and behavior.

In-vivo dose determination in a human after radon exposure: proof of principle

Radon-222 is pervasive in our environment and the second leading cause of lung cancer induction after smoking while it is simultaneously used to mediate anti-inflammatory effects. During exposure, radon gas distributes inhomogeneously in the body, making a spatially resolved dose quantification necessary to link physical exposure conditions with accompanying risks and beneficial effects. Current dose predictions rely on biokinetic models based on scarce input data from animal experiments and indirect exhalation measurements of a limited number of humans, which shows the need for further experimental verification. We present direct measurements of radon decay in the abdomen and thorax after inhalation as proof of principle in one patient. At both sites, most of the incorporated radon is removed within ~ 3 h, whereas a smaller fraction is retained longer and accounts for most of the deposited energy. The obtained absorbed dose values were 1.5 pm 0.3 µGy (abdomen, radon gas) and 1.1 pm 0.4 µGy (thorax, radon and progeny) for a one-hour reference exposure at a radon activity concentration of 55 kBq m−3. The accumulation of long-retained radon in the abdomen leads to higher dose values at that site than in the thorax. Contrasting prior work, our measurements are performed directly at specific body sites, i.e. thorax and abdomen, which allows for direct spatial distinction of radon kinetics in the body. They show more incorporated and retained radon than current approaches predict, suggesting higher doses. Although obtained only from one person, our data may thus represent a challenge for the barely experimentally benchmarked biokinetic dose assessment model.

Intercomparison of Radon Flux Monitors at Low and at High Radium Content Areas under Field Conditions.

Interlaboratory exercises are a good tool to compare the response of different systems to the same quantity and to identify possible inconsistencies between them. One of the main goals of the EMPIR 19ENV01 traceRadon project is to harmonize radon flux measurements based on different systems and methodologies. In the framework of the traceRadon Project, two radon flux intercomparison campaigns were carried out in October 2021 at high and at low radon source areas. Four institutions participated in the field intercomparison exercises with their own systems. Every system was based on a specific radon monitor (diffusion or pump mode) and an accumulation chamber (with manual or automatic opening). Radon fluxes were calculated by each participant using both exponential and linear fittings of the radon activity concentration measured over time within the accumulation chambers. The results of this study show mainly: (i) the exponential approach is not advisable due to the variability of the radon flux and the leakage of the systems during long-time measurements; (ii) the linear approach should be applied to minimize the measurement period in agreement with the time response and sensitivity of the monitors; (iii) radon flux measured at high radon source areas (radium content of about 800 Bq kg−1) risks being underestimated because of the influence of advective effects; (iv) radon flux measured at low radon source areas (radium content of about 30 Bq kg−1) may present large uncertainties if sensitive radon monitors with pump mode are not used.

Assessment of the tectonic effects on soil radon activity along the margin of the Arabian plate boundary in northwestern Syria

The main purpose of the present study is to assess the role of active tectonics in influencing the emanation level of soil radon across two tectonically active structures of the Northern Dead Sea Fault (NDSF) in northwestern Syria: namely, the Qastoon and Al-Harif fault segments. The radon measurements were basically directed by the results drawn from earlier studies of archaeoseismic and paleoseismic investigation in Al-Harif, besides integrated geophysical and morphotectonic survey at the Qastoon site. In view of that, a total of 80 soil gas radon points were measured in this work with sampling depth of 75 cm, using AlphaGUARD PQ 2000Pro radon detector. The background range of normal radon emission from local soil was determined in area located away from the influence of the tectonic disturbances. The obtained radon data were statistically analyzed and the mean values have been standardized in terms of probability of magnitude which enhances the comparison process and so facilitating the separation of normal radon variations from other anomalous or geotectonic related values. The overall results revealed remarkable occurrences of fault-associated radon anomalies with maximum peak values of ~6 to 7 times above the background, trending in accordance with the predicted traces of the fault ruptures at the Qastoon and Al-Harif, respectively.

Determination of the indoor radon concentration in schools of Tenerife (Canary Islands): a comparative study

A radon survey was carried out in 18 high schools located in Tenerife Island when anti-pandemic strategies were used to reduce COVID-19 dissemination during 2021. High schools were located in radon-prone areas previously identified by the Spanish Nuclear Safety Council. Our results showed that 12 high schools presented radon activities lower than 100 Bq/m3, 5 high schools presented values in the range 100–200 Bq/m3, and only 1 high school presented radon activity concentration higher than 200 Bq/m3. Such values are below the reference level (300 Bq/m3) recommended by the Spanish legislation in the Basics Document of Health Standards (section HS6) of the Technical Building Code and the European Union directive (2013/59/EURATOM). Assuming an indoor occupancy time of about 1620 h per year, the annual dose contribution due to indoor radon exposure ranged from 0.07 to 1.18 mSv/year. Comparing such result against previous values reported in the literature on the island of Tenerife, we conclude that during the pandemic situation the indoor radon concentration (median valued) was reduced from 130.9 (2007) to 73.5 (2021) Bq/m3. Finally, continuous indoor radon concentration measurements were obtained to study short-time fluctuations (intra-day changes) under different ventilation conditions.

Radon risk assessment and mitigation deadlines

Background: Radon is a radioactive natural gas that is the leading cause of death from lung cancer in non-smokers. It is responsible for the highest share of the yearly effective doses a person is exposed to, and, in many cases, it is the most important indoor pollutant. National regulations on radon typically use derived reference levels, except for occupationally exposed workers that are monitored using a graded approach (e.g. in Switzerland and EU). However, in some countries, radon concentrations in dwellings or workplaces are high and the effective doses are comparable, and even greater than those measured in occupational workplaces. The times spent in different places and the presence of children or disabled people (that usually spend more time indoor) bring a need for assessing the risks of indoor radon exposure using a graded approach for both dwellings and workplaces. It is essential to highlight that the Covid-19 pandemic made more people work from home, and this new situation may be permanent for some workers.&#x0D; Objective and Design: On this basis, the objectives of this work are to demonstrate the importance of adequate monitoring of natural radioactivity, simulate effective doses due to radon with the new effective dose coefficients (EDCs) proposed by International Commission on Radiological Protection (ICRP) (publication 137), show case studies that illustrate the need for effective dose calculation and propose a method to set radon mitigation deadlines for buildings with high radon activity concentrations. Moreover, this work will shed light in the question about the possible need for new radon reference levels after the new EDCs were proposed.&#x0D; Conclusions: One important outcome of this work is the application of the dose approach in a case study conducted in a dwelling, the measurements and calculations show high annual effective doses (up to 350 mSv/year).

Application of the Fractional Riccati Equation for Mathematical Modeling of Dynamic Processes with Saturation and Memory Effect

In this study, the model Riccati equation with variable coefficients as functions, as well as a derivative of a fractional variable order (VO) of the Gerasimov-Caputo type, is used to approximate the data for some physical processes with saturation. In particular, the proposed model is applied to the description of solar activity (SA), namely the number of sunspots observed over the past 25 years. It is also used to describe data from Johns Hopkins University on coronavirus infection COVID-19, in particular data on the Russian Federation and the Republic of Uzbekistan. Finally, it is used to study issues related to seismic activity, in particular, the description of data on the volumetric activity of Radon (RVA). The Riccati equation used in the mathematical model was numerically solved by constructing an implicit finite difference scheme (IFDS) and its implementation by the modified Newton method (MNM). The calculated curves obtained in the study are compared with known experimental data. It is shown that if the model parameters are chosen appropriately, the model curves will give results that correlate well with real experimental data. Moreover, with other parameters of the model, it is possible to make some prediction about the possible course of the considered processes.

Radon metrology for use in climate change observation and radiation protection at the environmental level

Abstract. Radon (222Rn) gas is the largest source of public exposure to naturally occurring radioactivity and the identification of radon priority areas is required by the Council Directive 2013/59/Euratom. Radon is also used as a tracer to improve atmospheric transport models and to indirectly estimate greenhouse gas (GHG) fluxes using the Radon Tracer Method (RTM). This method is based on the correlation between atmospheric concentrations of radon and GHG, together with information on the radon flux data. For radiological data, all European countries have installed networks of automatic gamma dose rate monitoring stations and report the real-time information gathered to the European Radiological Data Exchange Platform (EURDEP). So far, atmospheric radon activity concentrations and radon fluxes are not yet reported in EURDEP, nor routinely measured within the European radiological networks although these observations could help to avoid false positives results. Due to above applications, there is a need of building a metrological chain to ensure high quality radon activity concentrations and radon flux measurements. Both climate and radiation protection research communities underline the need for improved traceability in low-level atmospheric radon measurements (Khanbabaee et al., 2021). The EMPIR project 19ENV01 traceRadon1 is aimed towards providing the necessary measurement infrastructure and transfer standards to fulfil this need. Results of this project are particularly important for improving independent GHG emission estimates that support national reporting under the Paris Agreement on climate change and for the Council Directive 2013/59/Euratom, thus benefitting two large scientific communities. In this paper, early results, such as new activity standard developments and an overview of commercial and research radon monitors are presented and discussed. These results will feed into the traceRadon project with respect to radionuclide metrology in air and its potential for the improvement of the RTM.