Search Results (31)

This paper reports the levels of radon (Rn), thoron (Tn), and their progeny (TnP) concentrations in dwellings; studies factors influencing these concentrations; and assesses the associated lung cancer risk in Akonolinga’s area in Cameroon, where rutile deposits have been identified but are not yet industrially exploited. Indoor Rn and Tn were determined using CR39-based detectors. Additionally, Rn in soil gas, ²²⁶Ra, and ²³²Th concentrations in soil were measured using Markus 10, high purity germanium detector (HPGe), respectively. On average, indoor Rn, Tn concentration, and the equilibrium equivalent Thoron concentration (EETC) or TnP were 39.5, 68.1, and 5.0 Bq m⁻³, respectively. Average concentrations of Rn in soil gas, ²²⁶Ra, and ²³²Th in soil were 24.3 kBq m⁻³, 17 Bq kg⁻¹, and 27 Bq kg⁻¹, respectively. Correlation analysis indicates that indoor radon and thoron levels were tightly linked with factors such as their precursor concentrations in soil, the building materials, dwelling architecture, and inhabitant living habits. Furthermore, it was observed that Rn and TnP were the major contributors to the inhalation effective dose, accounting for 39.6% and 56.7% of the total, respectively. The estimated excess lifetime cancer risk (ELCR) from the exposition to Rn and TnP was found to be 2.93 × 10⁻³ and 4.36 × 10⁻³, respectively, exceeding the global average, raising health concerns. Full article

(1) Background: As the demand for ²¹²Pb for clinical theranostics rises, empirical studies that examine the radiation safety implications of different ²²⁴Ra sources are needed to facilitate discussions with local authorities for the translation of ^203/212Pb theranostics routine clinical practice. (2) Methods: Environmental ²²⁰Rn (Thoron) emanation was detected by a RAD7 detector in the vicinity of respective ²¹²Pb sources and additional alpha-dosimeters to detect ²²⁰Rn during generator elution, radiosynthesis, and quality control. Personnel gamma exposure was measured using whole-body and ring dosimeters. Generators included those based on wet-chemical-process- and emanation-based technology. (3) Results: During generator handling, varying levels of ²²⁰Rn were observed in the vicinity of generators. An additional monthly whole-body dose must be considered when handling different sources of ²¹²Pb generators, and this depends upon local shielding and the handling approaches toward use of the technology. (4) Conclusions: ²²⁴Ra in any form (including radionuclide generators) should always be handled within a fume hood to keep potential contamination and exposure to personnel as low as reasonably achievable. Following standard practices of radiation safety, generators of ²¹²Pb can be used safely for theranostic applications. Full article

In addition to cheap track-etch and expensive research-grade radon monitors, for several years, a new generation of affordable consumer-grade active monitors has been available. Their performance raises the question of whether they could also be used for certain objectives in a scientific context. This requires particular QA/QC as well as understanding their behavior and their limitations. This paper reports experiences with the RadonEye acquired over approximately two years, mainly for recording time series of radon concentration indoors and outdoors. Specific topics include calibration uncertainty, assessed by recording parallel time series; response to thoron by exposing the monitor to thorium-bearing material; and some unresolved questions related to measurement statistics to date. The main results are that factory calibration is quite uncertain and that sensitivity to thoron has to be considered in practical usage. Some identified statistical issues regarding the occurrence of anomalies and possible non-Poisson uncertainty remain unresolved. Full article

An analysis of the international radon regulatory framework identified actual challenges for the design and conduct of indoor radon surveys, though there is little discussion on this issue in the radon community. The main challenges hindering the development of radon regulation on an international scale, particularly in indoor radon surveys include the following: (i) responsibility for indoor radon testing and mitigation, (ii) excessive focus on Radon Priority Areas, (iii) the role of temporal uncertainty in indoor radon testing, (iv) the standardization of indoor radon measurements, and (v) the standardization of thoron EEC measurements and indoor testing. To address these gaps and inconsistencies, actual needs for design and conduct of indoor radon surveys are proposed, covering the aforementioned challenges. The needs statement, including a discussion of solutions, addresses the following key aspects of radon regulation: (1) legislation, (2) radon measurements, (3) awareness, and (4) building protection. The focus remains on the radon measurement aspect, detailing the strategy and tools for conducting indoor radon surveys within a rational approach. This includes the main research activities necessary for the sustainable development of global radon regulation. The final part of the article presents a Rational Method (protocol) of indoor radon measurements serving as a detailed guideline for standardizing indoor radon testing at the international level. This ensures the decision-making reliability of at least 95% and harmonizes relevant national approaches considering traditional measurement protocols using both short-term and long-term measurements. The proposed solutions aim to achieve the goal of a modern design and conduct of indoor radon surveys that are consistent with large-scale (mass) testing and effectively identify hazardous buildings. These solutions are based on a rational approach with convenient tools and active voluntary participation of the population to be implemented within the framework of national radon regulation. Full article

The application of energy-saving policies in buildings could lead to a decrease in the air exchange rate in dwellings, which could consequently lead to an increase in indoor radon concentration and, therefore, to an increase in resident exposure to ionizing radiation. The aim of the research presented in this paper is to investigate radiological exposure to residents due to the usage of different granites commonly used in Serbia as a building material. From the total of 10 analysed granite samples, a wide range of radon and thoron exhalation rates were found: from <161 μBq m⁻² s⁻¹ to 5220 ± 200 μBq m⁻² s⁻¹ and from <7 mBq m⁻² s⁻¹ to 5140 ± 320 mBq m⁻² s⁻¹, respectively. Assuming a low air exchange rate of 0.2 h⁻¹, the contribution of the measured granite material to the indoor radon concentration could go up to 150 Bq m⁻³. The estimated annual effective doses due to exposure to radon and thoron exhalation from the granite samples were (0.05–3.79) mSv and (<0.01–1.74) mSv, respectively. The specific activity of radionuclides ranged from 6.6 ± 0.5 Bq kg⁻¹ to 131.8 ± 9.4 Bq kg⁻¹ for ²²⁶Ra, from 0.5 ± 0.1 Bq kg⁻¹ to 120.8 ± 6.5 Bq kg⁻¹ for ²³²Th, and from 0.22 ± 0.01 Bq kg⁻¹ to 1321 ± 86 Bq kg⁻¹ for ⁴⁰K. The obtained external hazard index ranged from 0.03 to 1.48, with three samples above or very close to the accepted safety limit of 1. In particular, dwellings with a low air exchange rate (causing elevated radon) could lead to an elevated risk of radiation exposure. Full article

Studies on the individuation of surface and buried faults in seismic areas using geochemical methods can be considered a valid approach for improving sustainability in the risk assessment framework. Appropriate scientific knowledge of structural geology and its evolution pre/during/post seismic events can play a fundamental role in human safety and resilience. The Abruzzo region (central Italy) underwent to a Mw 6.3 seismic event, in April 2009, that interested L’Aquila city (the county seat of the region) and many villages in the surrounding area. A first soil gas survey including radon (²²²Rn) and thoron (²²⁰Rn) measurements was accomplished soon after the main shock, in an area of ~24 km² a few kilometers away from L’Aquila city. Results highlighted the spatial influence of the active tectonic on gas migration towards the surface. The area was investigated again in spring 2016, both to evaluate the natural degassing during a period without further meaningful earthquakes and to verify the presence of faults supposed after the previous survey results. Comparing data from the two surveys, a variation in the ²²²Rn/²²⁰Rn ratio was observed, suggesting different sources (deep or superficial) of gas degassing strictly correlated with the temporal variation in soil vertical permeability. Furthermore, the results infer a new structural system different from that known in the literature. Full article

This study presents the results of a pilot survey utilizing an innovative DVD-based method to measure outdoor radon and thoron levels. Twenty-six discriminative radon/thoron detectors were deployed across four different territorial zones in Bulgaria. Positioned 1 m above the ground, these detectors were left in place for several months. Notably, the dataset reveals significant variability in measurements, even over short distances, with thoron exhibiting greater variability than radon. Radon levels ranged from 7 ± 1 to 34 ± 3 Bq m⁻³ (average: 21 Bq m⁻³), while thoron levels ranged from 13 ± 5 to 307 ± 54 Bq m⁻³ (average: 170 Bq m⁻³). A weak but statistically significant correlation (correlation coefficient: 0.559) was observed between radon and thoron levels, which improved significantly when averaged across the four zones. These findings underscore the importance of measuring both radon and thoron in outdoor surveys. High thoron levels can significantly bias radon measurements, particularly when radon concentrations are substantially lower than those of thoron. If further studies confirm the good correlation between area averages, the observed correlation between area-average values could be used to correct average radon levels in large areas (e.g., radon priority areas) for thoron interference when thoron data are missing from the analyzed radon dataset. Full article

Building materials, such as brick and concrete, are known indoor radon (²²²Rn) and thoron (²²⁰Rn) sources. Most radon and thoron exhalation studies are based on the laboratory testing of pieces and blocks of such materials. To discuss if laboratory findings can be applied to a real-world environment, we conducted intensive in situ exhalation tests on two solid concrete interior walls of an apartment in Japan for over a year. Exhalation rates of radon (J_Rn) and thoron (J_Tn) were measured using an accumulation chamber and dedicated monitors, alongside monitoring indoor air temperature (T) and absolute humidity (AH_in). There were weak correlations between J_Rn or J_Tn and T or AH_in at one tested wall, and moderate correlations of J_Rn and strong correlations of J_Tn with T or AH_in at the other wall, meaning more or less seasonal variations. The findings aligned with previous laboratory experiments on J_Rn but lacked corresponding data for J_Tn. Additionally, a moderate or strong correlation between J_Rn and J_Tn was observed for both tested walls. Comparison with theoretical calculations revealed a new issue regarding the impact of each process of emanation and migration within concrete pores on radon and thoron exhalation. Overall, this study provides insight into parameterizing radon and thoron source inputs in modeling the spatiotemporal dynamics of indoor radon and thoron. Full article

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. Full article

Radon (²²²Rn) is the second most common cause of lung cancer after smoking. As radon poses a significant risk to human health, radon-affected areas should be identified to ensure people’s awareness of risk and remediation. The primary goal of this research was to investigate the local natural radioactivity (in soils, groundwater, and indoors) because of the presence of tuff outcrops (from middle–lower Pleistocene volcanic activity) that naturally produce radioactive gas radon at Cerveteri (Rome, Central Italy). The results of the radon survey highlighted moderate (>16,000 Bq/m³) but localized anomalies in soils in correspondence with a funerary site pertaining to the Etruscan Necropolis of Cerveteri, which extends over a volcanic rock plateau. Indoor radon measurements were performed at several tuff-made dwellings, and the results showed medium-low (<200 Bq/m³) values of indoor radon except for some cases exceeding the reference level (>300 Bq/m³) recommended by the 2013/59 Euratom Directive. Although no clinical data exist regarding the health effects of thoron (²²⁰Rn) on humans, the study of ²²⁰Rn average activity concentration in the soil gas survey reveals new insights for the interpretation of radon sources that can affect dwellings, even taking into account the considerable difference in the half-lives of ²²²Rn and ²²⁰Rn. Full article

This study aimed to investigate the differences in the relationship between radon and its progeny concentrations and particulate matter concentrations under varying pollution weather conditions. Outdoor radon and its progeny concentrations were measured by a radon/thoron- and radon/thoron progeny monitor (ERS-RDM-2S) during haze and dust storm weather in Beijing. Particulate matter concentrations and meteorological data were simultaneously recorded. Results showed that radon and its progeny concentrations exhibited a diurnal variation pattern, with a minimum in the late afternoon and a maximum in the early morning. The average radon concentrations were similar under both pollution weather conditions, but significantly higher than the reported average for Beijing. The equilibrium equivalent radon concentration during haze was about two times that during a dust storm. PM10 concentrations were similar in both pollution weather conditions, but PM2.5 concentrations during haze were approximately 2.6 times higher than that during dust storms. A positive correlation was observed between radon and its progeny concentrations and particulate matter concentrations, but the correlation was significantly higher during haze than during dust storms. The higher PM2.5 concentration during haze significantly increased the correlation between radon and its progeny concentrations and particulate matter concentrations. We recommended protecting against radon exposure during pollutant weather, especially haze. Full article

Radon, an element of natural radiation, is considered one of the leading causes of lung cancer worldwide. In Bangladesh, radon has been clarified as a foremost source of radiation exposure. Potential natural-radiation-induced elevated cancer risks were estimated in Bangladesh previously for the population. In this survey, as a very preliminary study in the country, comparative indoor radon (²²²Rn, Rn) and thoron (²²⁰Rn, Tn) concentration/population exposure was determined for the multistoried dwellings of south-western areas of Dhaka city. RADUET was used to assess annual Rn and Tn concentrations in determining the primary inhalation dose for the population. The annual effective dose of Rn and Tn was evaluated in this study for dwellings at 0.3 mSvy⁻¹, constituting a Tn dose contribution of an average of 40% with a dwelling-based wide range of 10–96%. Thus, Tn should not be neglected for Bangladesh while estimating radiological inhalation dose from the indoor environment. Again, the equilibrium factors, F of Rn and Tn, were determined by short-term measurement at averages of 0.6 and 0.02, respectively. Furthermore, using questionnaire estimation by principal component analysis, PCA following the dwelling characteristics, human lifestyles, and estimated long-term indoor Rn and Tn concentrations, this paper discussed indoor atmospheric/Rn factors for the investigated multistoried dwellings in Dhaka city. Full article

Accurate measurement of low-level thoron gas and high-accuracy calibration of thoron measurement devices are essential for assessing and preventing thoron radiological risks. This study aimed to develop a thoron gas measurement technique using an airflow-through scintillation cell for both low-level measurement and high-accuracy calibration. To achieve this, a compartment model was developed to estimate the influence of progeny deposition and accumulation on the wall of the scintillation cell to prevent an overestimation of thoron. A self-developed scintillation cell was utilised to implement and validate this technique. The lower detection limit and measurement uncertainty were then evaluated to assess the feasibility of the technique for low-level measurement and high-accuracy calibration. The results showed that the compartment model effectively addressed the influence of progeny deposition. The measurement technique achieved a lower detection limit below 100 Bq m⁻³ even with the coexistence of that of 100 Bq m⁻³ of radon and attained a measurement uncertainty (k = 2) below 10% when the concentration of thoron exceeded 1000 Bq m⁻³. In summary, this study developed a reliable and practical thoron gas measurement technique using an airflow-through scintillation cell with a consideration of progeny deposition, and is expected to contribute to the assessment and prevention of thoron radiological risk. Full article

The objective of this work was to perform a series of measurements of radon and thoron exhalation in the underground workings of an experimental coal mine. In the years 2012–2015, experiments on underground coal gasification were carried out in a coal mine, which caused, among other effects, damage to rock mass. Afterward, periodic increases in the concentration of potential alpha energy (PAEC) of radon decay products in the air were found, which could pose a hazard to miners. The question posed was whether the gasification experiment resulted in the increased migration of radon and thoron. If so, did it increase the radiation hazard to miners? The adaptation of the existing instrumentation to the specific conditions was conducted, and a series of measurements were made. It was found that the measured values of radon and thoron exhalation rates ranged from 3.0 up to 38 Bq·m⁻²·h⁻¹ for radon and from 500 up to 2000 Bq·m⁻²·h⁻¹ for thoron. Full article