Soil Gas Radon Research Articles

Occupational and Environmental Cancer

Environmental pollution is one of the main causes of disease, death, and disability worldwide. International Labor Organization (ILO) estimates mortality caused by occupational cancer worldwide to be two times higher than occupational accidents. Approximately, 10 important risk factors account for 85% of all occupational cancers. Factors for occupational cancer includes Asbestos, chemicals such as aniline, chromates, dinitrotoluene, arsenic and its inorganic compounds, beryllium and its compounds, cadmium and nickel compounds, wood dust, crystalline silica, brown coal phosphors, furnace emissions, pollution caused by diesel equipment, Nano-Materials, biological agents, ionizing radiation and non-ionizing radiation, thermal shock, shift work, stress and work while sitting. Also some other environmental factors can cause cancer which concludes air, water and soil pollutions, smoking, sunlight, radon gas, electromagnetic fields, agriculture, behavior and lifestyle (such as alcohol and tobacco consumption, diet, sleep patterns, personal habits and social and cultural environment behaviors). More than 75% of mortality due to cancer can be avoided via controlling occupational and environmental risk factors. Most of cancers are not hereditary and caused by occupational and environmental biological agents, and are potentially preventable. So, it is recommended that more researches should be performed in this field in order to detect more scientific and effective methods to detect number and type of cancers due to occupational and environmental factors.

Soil radon gas in some soil types in the rainy season in Ho Chi Minh City, Vietnam

Field experiments on soil radon and radium concentrations were carried out in eighteen locations in Ho Chi Minh City, Vietnam. Soil radon depth profiles (10–100 cm) of loam, sand and clay soil samples in the rainy season were measured using RAD7 radon detector. Mean concentrations of 222Rn and 226Ra were found to be 28.6 ± 2.0 Bq.kg−1 and (1.56 ± 0.06) × 104 Bq.m−3 in clay soil while they are 31.2 ± 2.5 Bq.kg−1 and (1.15 ± 0.05) × 104 Bq.m−3 in loam soil. They are 30.7 ± 2.0 Bq.kg−1 and (9.37 ± 0.52) × 103 Bq.m−3 in sandy soil, respectively. Values of radon diffusion length and diffusion coefficient for different soils were obtained using semi-empirical fit method linked to the poor diffusion of gas in clay soil (0.2 × 10−6 m2 s−1), the moderate diffusion coefficient (0.9 × 10−6 m2 s−1) in loam and good diffusion of radon gas in sandy soil (1.4 × 10−6 m2 s−1). An unexpectedly unclear linear relation was found between soil radon concentration and radium content. The grain size smaller than 0.1 mm was dominant reason for the lowest (0.15 ± 0.01) and highest (0.40 ± 0.03) values emanation coefficient for sand and clay soil, respectively. A strong positive correlation was found between radon concentration and soil pH level leads to soil pH is an indirect dynamic parameter affecting the migration of radon in soil.

The natural radioactivity of Istria, Croatia

Because of the geological structure of the Istrian peninsula which mainly consists of limestone that is characterized by karstic topography on its surface, it is expected that there are areas with elevated radon levels in soil gas as well as inside buildings (e.g. houses, kindergartens, schools). Recently, from autumn 2013 until spring 2015, more than 1200 radon measurements at about 500 randomly selected locations (in houses as well as in schools and kindergartens) were performed. The average value of indoor radon in homes is 102 Bq m−3 while the average radon concentrations in kindergartens (181 Bq m−3) and schools (208 Bq m−3) are approximately two times higher than in homes. In fact, in 15.5% of kindergartens and 21% of schools, the average indoor radon concentration is higher than 300 Bq m−3 which is the reference level in Croatia.Radon concentrations in soil gas in the Istrian peninsula were measured from 2013 to 2015 with the AlphaGUARD and RM-2 measuring systems. The obtained average value of 90 kBq/m3 and geogenic radon potential of 74 classifies the soil of Istria County into soil of high geogenic radon potential. It is important to emphasize that there are areas with radon concentrations up to 500 kBq m3. Soil samples were collected according to the standard procedures of the IAEA at 48 different locations. Activity concentrations of selected radionuclides were determined by means of gamma spectrometry by using an ORTEC HPGe detector system. The correlation between radon and its parents radium/uranium were investigated. The linear relationship between GRP and indoor radon per grid cell was found. The influence of climate condition on indoor radon concentration was observed. In accordance with the obtained results, areas with elevated indoor radon levels as well as levels of radon in soil gas were identified and geogenic and indoor radon maps were generated.

Correction to: Spatial distribution mapping and radiological hazard assessment of groundwater and soil gas radon in Ekiti State, Southwest Nigeria

In the original publication, the author name M. U. Khanderkar was published incorrectly. The correct name should be M. U. Khandaker.

Assessment of Soil Gas Radon and Exhalation Studies in Lower Himalayan Region of Jammu and Kashmir State, India

In the present work, the soil gas radon survey has been carried out for locating the trend of soil radon in the foothills of Siwalik which is covered with lithology of Pliocene unconsolidated deposits. Soil gas radon concentration and mass exhalation rate have been studied in natural soil samples of Udhampur district, Jammu and Kashmir, India using active measurement technique RAD7 and smart RnDuo monitor. The sampling measurements were chosen according to suitability of the area. Few of the locations are near the Main Boundary Thrust (MBT) and tectonically active lineaments, having reasonably high concentration of soil gas radon. The soil gas radon concentration in 15 locations of studied area has been measured at different depths (30, 45 and 60 cm) and the overall soil gas concentration was found to vary from 0.14 to 61.01 kBq m−3, respectively. This large variation in radon content might be due to radioactive nature of the bedrocks present in different geological structure. Soil pore diffusion model have been used to observe the relation between experimentally and theoretically determined soil gas radon concentrations in the studied region.

Spatial distribution mapping and radiological hazard assessment of groundwater and soil gas radon in Ekiti State, Southwest Nigeria

Groundwater constitutes the major source of utility water in Ekiti State with the majority of the population depending on groundwater for drinking and other household uses. Soil in the area is commonly used as a component of building materials, which may produce radon in the indoor environment. Excessive concentrations of radon in water and soil can cause radiological health risks to human as witnessed by the increased cases of lung cancer among non-smokers in Nigeria, which may be traceable to the ingestion and inhalation 222Rn in drinking water and indoor air. In the present study, comparative in situ measurements of radon in groundwater and soil gas were carried out at one hundred selected locations across the Ekiti State in southwest Nigeria, using a RAD7 radon detector to generate a radon distribution map and to estimate radiation hazards due to radon. The concentrations of radon in groundwater ranged from 0.9 to 472 Bq L−1 with a mean of 34.7 ± 4.4 Bq L−1, while those of soil gas ranged from 0.1 to 315 kBq L−1 with a mean of 38.9 ± 1.4 kBq L−1. The total annual effective dose due to inhalation and ingestion of radon in groundwater amounted to 94.7 µSv year−1, which is lower than the reference dose of 100 µSv year−1 recommended by the World Health Organization (WHO). The radon map generated for groundwater and soil gas identified three distinct areas with radon levels ranging from low to high. The results of this study show that some locations (Emure, Gbonyin, Ijero and Ikole) show mean total annual effective doses which are higher than the recommended limit. It can then be inferred that the groundwater samples pose significant radiological hazards to the population and that the noticed increase in lung cancer cases may be attributed to the consumption of groundwater in the area.

Soil gas radon measurements for investigating the actual status of seismic quiescence along the bounding fault of the Ghab pull-apart basin in western Syria

El propósito de este trabajo consistió en investigar posibles cambios de radón relacionados con la zona de falla que pudieran mostrar alguna relación con la tectónica local a lo largo de la zona de falla de la cuenca de Ghab. A pesar de su actividad histórica, la falla de Ghab presenta actualmente una falta de actividad sísmica con un periodo largo de quietud sísmica. Se escogieron 7 sitios para realizar muestreos de radón utilizando un equipo ALPHAGUARD. El valor promedio normal de radón de fondo se obtuvo con medidas realizadas lejos de la zona de influencia de la falla. Se definió un rango estadístico de variaciones anómalas de radón con límites marcados por el valor promedio mas/menos dos desviaciones estándar (X+/- 2DS). Los resultados iniciales muestran incrementos de radón en las estaciones de monitoreo a lo largo de la zona de falla con picos 4-5 veces mayores que el nivel de fondo. Aunque estas concentraciones anómalas relativamente grandes podrían confirmar la utilidad del radón como un posible indicador para trazar los límites de la falla, no prueban necesariamente una relación con la actividad tectónica del área. Sin embargo, estos incrementos de radón podrían indicar una evidencia de zonas con mayor permeabilidad asociadas a la deformación de la estructura en la zona de ruptura.

Comparison of radon concentrations in soil gas and indoor environment of Afyonkarahisar Province

It is well known that radon is the main source of natural radiation exposure to the population. Indoor radon concentrations in an area are affected by ascending radon migration following the convection of groundwater and soil gas along fractures and faults in the bedrock sediments. There are various studies showing that positive radon anomalies in the soil gas are found to coincide with the locations of houses showing the highest concentrations. Moreover, soil gas radon levels and soil permeability are important factors in determining the radon potential of an area, because high permeability enables the increased migration of radon from the soil into houses. Since radon in homes originates mainly from soil gas radon, it is of public interest to study the correlation between soil gas radon and indoor radon in different geographic locations. In the present work, a correlation study was carried in conjunction with radon concentrations in soil gas and indoor environment of Afyonkarahisar Province. The provincial center was assumed to be divided into four regions according to the rock types and tectonic structure to show also the geological structure effect on radon concentrations. The indoor radon concentrations were measured in 74 dwellings using CR-39 passive nuclear track detectors, and the radon concentrations in soil gas were determined in 243 drilled holes using AlphaGUARD detector. The correlation coefficient of 0.97 was obtained between radon concentrations in soil gas and indoor environment of Afyonkarahisar Province.

Soil gas radon concentrations along the Ganos Fault (GF)

In this study, soil radon levels have been measured for the first time across the Ganos fault (GF), which is known as the western part of the North Anatolian Fault Zone. LR 115 Type 2 Solid State Nuclear Track Detectors (time integrated) have been applied to determine soil gas radon levels, and the survey was performed in 16 stations along the fault line. The results showed that soil gas radon concentrations and variation of concentration levels are comparable high along the fault line. It is also observed that in the middle of the Ganos Fault, fairly elevated radon levels were detected. These can be related to the activity of the fault lines. It is confirmed that the study area has a very active tectonic structure and is great location for analyzing radon variations.

Across-fault distributions of radon concentrations in soil gas for different tectonic environments

The radon concentration in soil gas at the crustal surface is closely related to the development of local fractures. Therefore, the spatial variation in soil-gas radon concentrations across faults differs between fault zones located in different tectonic environments. This study investigates the Beiluntai thrust fault and the Haiyuan strike-slip fault in west China, which are assumed to be typical examples of the different types of faults. Radon concentrations in soil gas were measured at various locations around these faults, and the spatial variation in these concentrations was characterized along fault-perpendicular profiles. For normal fault, our results indicate that concentrations are usually highest at the fault, and decrease gradually away from the fault in either direction. For thrust, however, concentrations increase in the hanging wall approaching the fault, but decrease sharply at the fault. For strike-slip fault with extension across the fault, soil-gas radon concentrations are relatively high at the fault, and decrease gradually with distance from the fault. For strike-slip fault with contraction across the fault, soil-gas radon concentrations are relatively low at the fault, and increase gradually with distance from the fault.

Study of radon/thoron exhalation rate, soil-gas radon concentration, and assessment of indoor radon/thoron concentration in Siwalik Himalayas of Jammu & Kashmir

ABSTRACTIn the present study, the soil-gas radon concentration was assessed at different depth intervals, i.e., 15 cm, 30 cm, 60 cm, and 100 cm from the 30 villages of Jammu & Kashmir, India using RAD7, an electrostatic solid state alpha detector. The radon mass exhalation and thoron surface exhalation rate has also been measured in the selected 18 soil samples out of 30 of different grain sizes (i.e., 1 mm, 300 µm, 150 µm). The active radon and thoron concentrations were also assessed in the 20 villages. Both the exhalation rates and active radon/thoron concentration were measured using SMART Rn Duo, a portable radon monitor. The average values of soil-gas radon concentration were 210 ± 84 Bq m−3, 1261 ± 963 Bq m−3, 4210 ± 1994 Bq m−3, and 671 ± 305 Bq m−3 at the depth intervals of 15 cm, 30 cm, 60 cm, and 100 cm, respectively. The exhalation rate of radon and thoron from soil was found to decrease with the increase of grain size, as smaller soil particles make relatively more contribution to radon and thoron exhalations from the ground surface than larger soil particles. The measured Pearson's correlation coefficient was obtained as statistically significant between different quantities under two-tailed test.

A COMPREHENSIVE STUDY OF RESIDENTIAL, GEOGENIC AND WATER RADON IN THE NORTH AREA OF MUREŞ COUNTY, ROMANIA.

This study presents results of a complex survey about residential, soil and water radon in the North of Mureş county (Romania). Indoor radon measurements were performed by using CR-39 track detectors, while radon concentrations in soil and in water were measured by using the LUK3C device and accessories. The indoor radon concentrations of 157 houses ranged from 9 to 414 Bq m-3, with an arithmetic mean of 131 Bq m-3 and a geometric mean of 105 Bq m-3. In ~3.2% of the investigated houses exceed the recommended reference level of 300 Bq m-3. The soil gas radon concentrations in 137 sampling points varied from 5.0 to 88.0 kBq m-3, with a geometric mean of 14.6 kBq m-3. Results of 190 water samples shows radon concentrations from 0.2 to 28.0 Bq L-1, with a geometric mean of 5.0 Bq L-1. Beside these results, indoor, soil and water radon maps were performed, divided into cells of 5 km × 5 km.

Correlations between the radon concentrations in soil gas and the activity of the Anninghe and the Zemuhe faults in Sichuan, southwestern of China

The Anninghe fault (ANHF) and the Zemuhe fault (ZMHF) with left-lateral strike-slip, located along the eastern boundary of the Sichuan-Yunnan block (southwestern of China), are some of the most active faults. These faults mainly control the seismicity of southwestern area of China. Measurement of soil gas radon (Rn) emitted from fault along the ANHF and the ZMHF has been carried out for the research of tectonic activity. We obtained the Rn concentrations at 394 sampling points along 15 profiles across the ANHF and the ZMHF in 2016. The measurement results show that the values of Rn in the ANHF are significantly higher than that in the ZMHF. The relative coefficient KQ of Rn activity attained in profiles of the ANHF ranges from 3.3 to 9.1, which are obviously higher than that of 2.1–2.5 in profiles of the ZMHF. The radon flow brings up the deeper and radon-richer gas upward through the high-level cracked strata caused by the tectonic activity accounts for the anomalously high values attained. The spatial variation of Rn in the concentration profile and the relative coefficient KQ calculated indicate that the tectonic activity of the south segment of the ANHF is significantly higher than that of the north segment of the ZMHF.

Radiological survey of the covered and uncovered drilling mud depository

In petroleum engineering, the produced drilling mud sometimes contains elevated amounts of natural radioactivity. In this study, a remediated Hungarian drilling mud depository was investigated from a radiological perspective. The depository was monitored before and after a clay layer was applied as covering.In this study, the ambient dose equivalent rate H*(10) of the depository has been measured by a Scintillator Probe (6150AD-b Dose Rate Meter). Outdoor radon concentration, radon concentration in soil gas, and in situ field radon exhalation measurements were carried out using a pulse-type ionization chamber (AlphaGUARD radon monitor). Soil gas permeability (k) measurements were carried out using the permeameter (RADON-JOK) in situ device. Geogenic radon potentials were calculated. The radionuclide content of the drilling mud and cover layer sample has been determined with an HPGe gamma-spectrometer. The gamma dose rate was estimated from the measured radionuclide concentrations and the results were compared with the measured ambient dose equivalent rate.Based on the measured results before and after covering, the ambient dose equivalent rates were 76 (67–85) nSv/h before and 86 (83–89) nSv/h after covering, radon exhalation was 9 (6–12) mBq/m2s before and 14 (5–28) mBq/m2s after covering, the outdoor radon concentrations were 11 (9–16) before and 13 (10–22) Bq/m3after covering and the soil gas radon concentrations were 6 (3–8) before and 24 (14–40) kBq/m3 after covering. Soil gas permeability measurements were 1E-11 (7E-12-1E-11) and 1E-12 (5E-13-1E-12) m2 and the calculated geogenic radon potential values were 6 (3–8) and 12 (6–21) before and after the covering. The main radionuclide concentrations of the drilling mud were CU-238 12 (10–15) Bq/kg, CRa-226 31 (18–40) Bq/kg, CTh-232 35 (33–39) Bq/kg and CK-40 502 (356–673) Bq/kg. The same radionuclide concentrations in the clay were CU-238 31 (29–34) Bq/kg, CRa-226 45 (40–51) Bq/kg, CTh-232 58 (55–60) Bq/kg and CK-40 651 (620–671) Bq/kg.According to our results, the drilling mud depository exhibits no radiological risk from any radiological aspects (radon, radon exhalation, gamma dose, etc.); therefore, long term monitoring activity is not necessary from the radiological point of view.

SIGNAL DECOMPOSITION AND ANALYSIS FOR THE IDENTIFICATION OF PERIODIC AND ANOMALOUS PHENOMENA IN RADON TIME-SERIES.

This work concerns continuous monitoring of radon and thoron specific activity in soil gas within the framework of identifying possible anomalies. It is based on the analysis of a medium-term data record obtained from soil gas in an area of geophysical interest. The RaMonA spectrometric system is also used to measure the climatic parameters and a specific analysis of the alpha spectra is performed to better determine the alpha lines intensity. Since radon emission is also influenced by meteorological parameters, it is mandatory to differentiate the changes due to the deep phenomena. Different procedures are utilized to reach the above objective: statistical analysis using the Empirical Mode Decomposition technique, the Multiple Linear Regression method and the Remote Radon Estimation by using of the thoron trend to eliminate the locally produced radon fraction. The results of such methods are compared to recognize and to highlight radon anomalies.

URANIUM IN SOIL AND GAMMA DOSE RATE AS PROXIES FOR THE INDOOR RADON RISK: SITUATION IN BELGIUM.

Radon risk maps are usually based either on indoor radon data, or on measurements of soil gas radon and soil permeability. If these data are not available or not sufficient, it was suggested that other data could be used as an approximate substitute (a proxy) to the missing information, like the concentration of 238U or 226Ra in soils or the terrestrial gamma dose rate (TGDR). We examine here the correlation between airborne measurements of soil U and indoor radon, and between airborne U and TGDR, and their link with affected/unaffected areas. No clear correlation is found between airborne U and affected areas, as strongly affected areas are not characterised by a higher U level. Only the moderately affected area of Condroz can be connected to a higher U level, related to a few U anomalies. TGDR shows a rather good correlation with airborne U, but its relation with radon risk is less clear. Soil uranium and TGDR may help to screen out areas with very low U and very low TGDR, which have a low indoor radon risk, but they cannot be considered as good proxies for predicting radon-affected areas in Belgium.

Spatial distribution correlation of soil-gas radon (222Rn) and mercury with leveling deformation in northern margin fault zone of West Qinling, China

This study concerns measurement of 222Rn and mercury concentrations in soil-gas in the northern margin fault zone of West Qinling, Tibet (China). Based on profiles crossing perpendicularly the different segments of the fault at six different locations, the relations between the gas measurements, fault deformation, and seismic activity in each segment of the studied fault were analyzed, determining seismic risks in the fault zone. Soil-gas data are heterogeneous, but appear relatively organized along the three segments of the fault. The detailed multidisciplinary analysis reveals complex interactions between the structural setting, uprising fluids, leveling and seismic activity in different fault segments. The results for both fault soil gas and deformation indicated relatively stronger fault activity in the Wushan segment in the middle-eastern segment of the northern margin fault zone of West Qinling and lower activity in the Zhangxian segment, whereas the fault in the Tianshui segment was relatively locked. Additionally, in the Wushan strike-slip pull-apart area, the active influence of fluid activities facilitated the occurrence of small to medium-sized seismic events, which prevented the occurrence of larger events; in contrast, in the Tianshui segment, the west Zhangxian segment, the weak fluid activities and the corresponding strain rate will probably lead to strong earthquake buildup.

Radon Concentration Measurements and Risk Assessments Around Uludağ Mountain (Bursa, Turkey)

The radon concentrations in the groundwater, tap water samples and soil gases of the residential areas and forested lands of Uludag were measured to research on the dynamics of low-high radon levels over the various rocks types found in this area. Besides, the annual effective doses for groundwater and tap waters were calculated and compared with the recommended dose value by the World Health Organization (WHO) to evaluate the health risk of inhabitant. The radon concentrations in water samples for the wet and dry seasons were found in the ranges of 0.17 ± 0.09 - 195.64 ± 6.87 Bq l -1 (median value of 5.13 Bq l -1 ) and 0.04 ± 0.01 - 199.24 ± 6.54 Bq l -1 (median value of 4.33 Bq l -1 ), respectively. Elevated radon concentrations were measured in the waters draining through igneous rocks (granite and granodiorite), known as uranium-rich rocks. The average radon and thoron concentrations of soil gases were found to be in the ranges of 0.65 ± 0.01 – 199.66 ± 3.27 kBq m -3 and 4.36 ± 0.36 – 245.9 ± 7.26 kBq m -3 , respectively. The highest and lowest radon and thoron concentrations in soil gases were observed in the granitic area and in scree region, respectively.

Evaluation of Radon Concentration in the Urban Area Foundation of Tirana, Albania

In this paper, we shortly are treating the results of the radon concentration in soil gas, which are obtained by a detailed study that was carried out during 2000-2005 years in the urban area of Tirana, Capital City of Albania. The field measurements were done by using Luk-4 equipment (Lucas method) and based on technique (Neznal et al. 1992, Neznal et al. 1994a, Neznal et al. 1994b, Neznal et al. 1996, Neznal et al. 2002b). From the analysis of the data taken by this research, was concluded that the level of the radon concentration in soil gas of Tirana urban area depends on the soil type. So, the highest level of radon gas (130.0 kBqm‐3) was observed in the inorganic clays and very fine sands with beige-red color (soils type 1), which is extended on the second terrace of Tirana River. This paper gives conclusions of soil gas radon concentration, where its value range from 0.9-1.54 kBqm‐3 up to 92.03-130.0 kBqm‐3. The results indicate that more than 50% of Tirana urban area is made of soils, which are characterized by high soil gas radon concentration, which constitutes a real risk for the Tirana’s residents.

Assesment of the response of the meteorological/hydrological parameters on the soil gas radon emission at Hsinchu, northern Taiwan: A prerequisite to identify earthquake precursors

The present study is an attempt to assess and quantify the influence of the meteorological (atmospheric temperature and pressure) and hydrological (rainfall and ground water head-GWH) parameters on the soil gas radon emission at Hsinchu, northern Taiwan. The quasi-periodic variations corresponding to diurnal and semi diurnal periods were estimated and eliminated by decomposing the time series for the period of September 16, 2009 to March 5, 2010 to singular spectrum analysis. The reconstructed non-periodic variations, which reproduce the salient feature of recorded time series, were searched for meteorological/hydrological influences in radon emission. The combined response of barometric pressure and atmosphere temperature are found to be small when compared to the total variability in radon. The influence of rainfall on radon is found to be strongest. At the onset of rainfall, radon shows a step-jump that attains peak with a time lag of 12–15h. This enhancement is attributed to entrapment of soil gas in the top soil cover as increased soil moisture prevents escape of radon into the atmosphere (capping effect). The decay of radon after the recession of rainfall is approximated by double exponential decay terms, one corresponding to the natural decay of radon with half life of 3.84days and second representing slow weakening of capping effect. The third effect related to internal loading due to rise and fall of groundwater modulates the propagation of radon in overlying strata, accounting for the long term variations in radon. The rainfall inflicted changes in radon look strikingly similar to earthquake related precursory or co-seismic perturbations, inferred by long term synotopic observations. It is surmised that unless radon variations are corrected for meteorological/hydrological contamination, some precursory signals are masked on one hand while on the other hand some anomalies are falsely viewed as earthquake precursors.