Mining activities are generally known to enhance the concentration of primordial radionuclides in the environment thereby contributing immensely to human exposure to ionizing radiation of terrestrial origin. Thus, the abandoned Tin and Cassiterite mining site in Oyun, Kwara State, Nigeria, is believed to cause radiological implications on local residents.  Assessment of radon concentration in surface water from the study area was carried out using RAD7-Active Electronic detector big bottle system. In order to ascertain the risk or hazard incurable in consuming such water, 12 samples were analysed and used in the estimation of annual effective dose of radon. The measured maximum and minimum radon concentrations were found to be 44.95 and 21.03 Bq/L with average of 35.86 Bq/L. These values are quite greater than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limits of 11.1.Bq/L. The estimated total effective dose (AEDEtotal) was found to be within the range of 206.52 and 441.41 μSvy-1, and an average of 352.20 μSvy-1 for Adults, 283.30 and 605.47 μSvy-1, and average of 483.10 μSvy-1 for Children, and finally, 321.70 and 687.47 μSvy-1 with average of 548.64 μSvy-1 for Infants, respectively. These values were higher than the recommended limit of 100 µSvy-1 and 200 µSvy-1 for adult and children respectively. Furthermore, worries should be noted about the probabilistic cumulative effect on the consumers of such water if the ingestion is for an extended period of time.

The adverse health effects associated with the inhalation and ingestion of naturally occurring radon gas produced during the uranium decay chain mean that there is a need to identify high-risk areas. This study detected radon-prone areas using a geographic information system (GIS)-based probabilistic and machine learning methods, including the frequency ratio (FR) model and a convolutional neural network (CNN). Ten influencing factors, namely elevation, slope, the topographic wetness index (TWI), valley depth, fault density, lithology, and the average soil copper (Cu), calcium oxide (Cao), ferric oxide (Fe₂O₃), and lead (Pb) concentrations, were analyzed. In total, 27 rock samples with high activity concentration index values were divided randomly into training and validation datasets (70:30 ratio) to train the models. Areas were categorized as very high, high, moderate, low, and very low radon areas. According to the models, approximately 40% of the study area was classified as very high or high risk. Finally, the radon potential maps were validated using the area under the receiver operating characteristic curve (AUC) analysis. This showed that the CNN algorithm was superior to the FR method; for the former, AUC values of 0.844 and 0.840 were obtained using the training and validation datasets, respectively. However, both algorithms had high predictive power. Slope, lithology, and TWI were the best predictors of radon-affected areas. These results provide new information regarding the spatial distribution of radon, and could inform the development of new residential areas. Radon screening is important to reduce public exposure to high levels of naturally occurring radiation.

Radon exhalation from soil and ores is among the most dangerous risks for the public health care. The impact becomes even more powerful when technological enhanced naturally occurring radioactive materials (TENORM) are used for public and private building. Here, we built a down-scaled model (a 1.0 m × 1.0 m × 0.5 m parallelepiped) of a dwelling, whose construction materials contain TENORM harvested in a site in Crotone (Italy). We observed an increase of the radon activity in the model when TENORM residues are employed, reaching a value around 120 Bq/m³, i.e. up to three times higher than the typical values of Crotone indoor environment, which ranges around 40 Bq/m³. These results have then been compared to a real use case. The correspondence found between the values of radon activity concentration in the model and in the use case suggests that estimating the radon concentration is a useful method to target TENORM presence inside buildings.

Mineral springs are used in spa resorts throughout the world. Radon is a natural radioactive source, which can dissolve, accumulate, and be transported by water. This study investigates the radon concentration in air and water in 12 Bulgarian rehabilitation hospitals and presents the assessment of the exposure to radon in them. The measurements were performed at 401 premises within 21 buildings, using two types of passive detectors for a dry and wet environment that were exposed from February, 2019 to June, 2019. The radon concentration varied from 19 to 2550 Bq/m³ with an arithmetic mean and a standard deviation of 102 Bq/m³ and 191 Bq/m³, respectively. The hypothesis that in hospitals the source of radon, besides soil under the buildings, is also the mineral water that is used for treatment was tested. Thermal water samples were procured sequentially from a spring and baths to analyse the reduction of radon concentration in them till reaching the premises. The results show that the concentration of radon decreased by approximately 50%. Further, the correlation analysis applied to the data proved the relation of the levels of indoor radon in the treatment rooms with those in the water. Mineral water used in rehabilitation hospitals have radon transfer coefficients ranging from 4.5·10⁻⁴ to 8.4·10⁻³. In addition, an analysis of the exposure of patients and workers to radon in rehabilitation hospitals based on the indoor radon levels and period of exposure was performed. The doses of workers do not exceed the limit of the annual effective dose for the population from all sources (1 mSv/year).

Uranium tailing ponds are a potential major source of radioactive pollution. Solidification treatment can control the diffusion and migration of radioactive elements in uranium tailings to safeguard the surrounding ecological environment. A literature review and field investigation were conducted in this study prior to fabricating 11 solidified uranium tailing samples with different proportions of PVA fiber, basalt fiber, metakaolin, and fly ash, and the weight percentage of uranium tailings in the solidified body is 61.11%. The pore structure, volume resistivity, compressive strength, radon exhalation rate variations, and U(VI) leaching performance of the samples were analyzed. The pore size of the solidified samples is mainly between 1 and 50 nm, the pore volume is between 2.461 and 5.852 × 10⁻² cm³/g, the volume resistivity is between 1020.00 and 1937.33 Ω·m, and the compressive strength is between 20.61 and 36.91 MPa. The radon exhalation rate is between 0.0397 and 0.0853 Bq·m⁻²·s⁻¹. The cumulative leaching fraction of U(VI) is between 2.095 and 2.869 × 10⁻² cm, and the uranium immobilization rate is between 83.46 and 85.97%. Based on a comprehensive analysis of the physical and mechanical properties, radon exhalation rates, and U(VI) leaching performance of the solidified samples, the basalt fiber is found to outperform PVA fiber overall. The solidification effect is optimal when 0.6% basalt fiber is added.

Although it is biologically plausible, findings relating radon exposure to the risk of cerebrovascular disease (CeVD) are inconsistent and inconclusive. To investigate whether radon exposure was associated with the risk of CeVD, we qualitatively and quantitatively summarized the literature on radon and CeVD in both occupational and general populations. A search of PubMed, Embase, Scopus, and Web of Science was performed for peer-reviewed articles published through March 2022. Studies were excluded if radon exposure was not assessed separately from other ionizing radiation. In the meta-analysis, excess relative risks (ERRs) were converted to relative risks (RRs), and the pooled RRs and 95% confidence intervals (CIs) were determined using the random-effects model (DerSimonian and Laird). In the systematic review, nine eligible studies were summarized. Six occupational studies indicated inconsistent associations between cumulative radon exposure and CeVD mortality among mine workers. With available data from four updated occupational studies (99,730 mine workers and 2745 deaths), the pooled RR of radon exposure with CeVD mortality showed a non-significant association (1.10, 95% CI 0.92, 1.31). Three studies (841,270 individuals and 24,288 events) conducted in general populations consistently demonstrated a significant inverse relationship between residential radon exposure and risk of CeVD. The existing literature suggested a potential link between radon exposure and CeVD risk in general population. The inconsistent association in occupationally exposed populations may be explained by different methods of radon assessment and other methodological issues. Since radon exposure is a common public health issue, more rigorously designed epidemiologic studies, especially in the general population are warranted.

Radiological impact of radon in air is a global issue whereas radon in water has local consequences. Considering its importance, we have conducted a study on radon activity measurements in 316 tube-well water samples collected from Susunia hill area in Bankura district of West Bengal, India during the period of 25th December 2018–2nd February 2020. Radon contents are measured using AlphaGUARD radon monitor. The obtained radon activities in drinking water samples lie between 1.78 ± 0.07 and 3213.50 ± 77.32 Bq/l with an average of 128.30 ± 14.09 Bq/l. This study reveals that 93% of the samples have radon levels in excess of the USEPA proposed maximum contamination level (MCL) of 11.1 Bq/l while radon levels of 40% samples have exceeded the WHO and EU Council Directive recommended reference level of 100 Bq/l. The total annual effective dose of the samples have been estimated by considering the per day water intake of 3 l. The calculated total annual effective dose widely fluctuates between 10.39 and 18649.55 μSv/year with an average value of 744.59 μSv/year. 269 water samples have exceeded the WHO and EU Council Directive recommended reference level of 100 μSv/year. However, if we consider the UNSCEAR prescribed annual water intake of 60 l, the average dose becomes 279.82 μSv/year. The situation demands attention of the local authorities. Local people are advised to take some easy preventive measures for their radiological protection against such contamination.

In this study, a total of 42 water samples were collected from Karasu and Pınarbası, which are two drinking water sources feeding the Kahramanmaras city center water distribution network, from sixteen cisterns fed from these water sources and twenty-four tap water receiving water from the cisterns. Radon concentrations and radon inhalation rates of these water samples were determined using a CR-39 passive trace detector. In natural spring water samples, radon concentrations and exhalation rates ranged from 174.7 ±18.7 Bq/m³ to 211.7± 30.7 ±10.7 Bq/m³ and 5.6 ± 0.6 mBq/m²h to 6.8 ± 1.0 mBq/m²h. In cistern water samples, radon concentrations and exhalation rates ranged from 80.6 ± 3.9 Bq/m³ to 303.0 ± 21.8 Bq/m³ and from 2.6 ± 0.1 mBq/m²h to 9.8 ± 0.7 mBq/m²h, respectively. In tap water samples, radon concentrations and exhalation rates ranged from 99.3 ± 5.5 Bq/m³ to 305.8 ±10.7 Bq/m³ and from 3.2 ± 0.2 mBq/m²h to 9.9 ± 0.4 mBq/m²h, respectively. These values are compared to the Environmental Protection Agency of the United States of America (USEPA), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the European Union (EU) Commission, and the World Health Organization (WHO)’s drinking water safe limit values. As a result, it has been determined that these values are far below the recommended safe limit values for drinking water. Also, the results of this study’s radon and exhalation rate tests are compared to those of comparable studies conducted in Turkey and other countries.

Distribution studies of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰ K in soil, statistical analysis of activity concentrations, and radiological safety assessment were carried out in the phosphate ore site of Dagbati, southern region of Togo. The measurements were done using high purity germanium (HPGe) detector gamma‑ray spectrometer. High values of activity concentrations of ²³⁸U and ²²⁶Ra measured were partially attributed to the nature of rocks and the geological structure of the studied area. Twenty-two out of 30 (73.33%) of soil samples presented values above the recommended limit for gamma-ray absorbed dose rate. Although the annual effective dose equivalent mean value of 0.68 mSv year⁻¹ (0.54 for indoor and 0.14 for outdoor) was below the recommended limit, more than 73% of soil samples were above. Similarly, external and internal hazard’s indices, gamma level index, and excess lifetime cancer risk vary from 0.06 to 1.69, 0.09 to 3.20, 0.15 to 4.19, and 0.00004 to 0.00123, respectively, with more than 73% soil samples having values above the recommended limit. These are indications that long-term exposure to natural radiation may lead to cancer risk. However, considering the level of uranium in soil samples, the mass exhalation rate of radon was investigated and the mean value of 1450 mBq kg⁻¹ h⁻¹ obtained is lower than the safe value of 57,600 mBq kg⁻¹ h⁻¹. Therefore, using phosphate mining soil as building material is safe in terms of radon exposition but might lead to radiation exposure and further an increase of cancer incidence for the population.

Natural radionuclides, radon exposure, soil particles, moisture, and dwellings from quarry towns in Greater Accra Region have been studied with hyper pure germanium detector (HPGe), passive radon detectors (CR-39), and sieving techniques. Soil formation and radioactivity levels have been estimated by determining correlation coefficient, clustering, principal, and factoring plot box. The average values for the ²²⁶Ra, ²³²Th, ⁴⁰ K, radon exhalation (²²²Rnₑᵣ), and indoor radon (²²²Rnᵢₙ) are 27 ± 13 Bq/kg, 31 ± 14 Bq/kg 132 ± 103 Bq/kg, 87 ± 40 µBq/m²h, and 77 ± 37 Bq/m³. Eighteen (18%) and fifteen (15%) percent of the studied radon exhalation from the soil and radon indoor concentrations in dwellings from quarry towns were found to be more than the level of 125 µBq/m²h and 100 Bq/m³ from UNSCEAR and WHO reference level respectively. The average values for moisture and gravel, sand, and fine particles were 10.6 ± 6%, 33 ± 18%, 33.2 ± 13%, and 33.0 ± 6%. Radon exhalation with gravel particles and moisture recorded the highest positive and negative correlations of 0.81 and 0.85. The radon exhalation relates with moisture and soil particles far better than the indoor radon. Single-cluster and close bond was found to exist between the radon exhalation and ²²⁶Ra concentration. Three dimensional clusters contributed to 86.6% cumulative measured data variance. The study indicated that soil particles and moisture content have direct influence on natural radioactivity and radon levels in both indoor and outdoor environments. Statistical analysis performed also indicated that the natural radionuclides and radon concentrations have both positive and negative relation with the moisture and soil particles.