Soil Radium Content Research Articles

Measurement of Effective Radium Content and Radon Exhalation Rates in Soil Samples of Adigrat, Tigrai Region, Ethiopia

The predominant source of radiation exposure for the global population is natural radiation, originating from radioactive elements present in the Earth's soil, air, and water. These elements, such as uranium, radium, and radon, have existed since the planet's formation. Prolonged exposure, particularly in specific geographic locations, significantly contributes to radiation risks for populations. Exposure routes include inhaling radon gas, ingesting radioactive substances in food and water, and direct exposure to terrestrial gamma radiation. While natural radiation exposure generally remains within safe limits, certain factors can elevate risks, such as geological formations rich in radioactive minerals or proximity to nuclear facilities. Environmental conditions and geological factors can also influence radiation levels, leading to fluctuations in exposure risks. Monitoring and regulating radiation exposure are crucial to prevent surpassing permissible levels, which can result in health hazards like an increased risk of cancer. Effective management requires ongoing research, stringent regulations, and public awareness efforts to mitigate the risks associated with natural radiation exposure and protect public health. Effective radium content and radon exhalation rates in soil samples collected from Adigrat in Tigrai state of Ethiopia were experimentally measured by ‘‘Sealed Can Technique’’ using LR-115 type II plastic track detectors. The values of effective radium content were found to vary from16.11 Bq/kg to 34.24 Bq/kg with an average value of 25.93 Bq/kg and a standard deviation of 6.10. The mass and surface exhalation rate has been found to vary from 1.61x10<sup>-6</sup> Bq kg<sup>-1</sup> d<sup>-1</sup> to 3.42 x10<sup>-6</sup> Bq kg<sup>-1</sup> d<sup>-1</sup> and 0.81x10<sup>-4</sup> Bq m<sup>-2</sup> d<sup>-1</sup> to 1.71x10<sup>-4</sup>Bq m<sup>-2</sup> d<sup>-1</sup>, respectively. The radium content in soil in the study area is below the permissible value of 370 Bq/kg as recommended by Organization for Economic Cooperation and Development.

Evaluation of outdoor radon levels and its dependence on the radium content in soil in the environs of Belagavi India

The paper presents the seasonal variation of outdoor radon levels and the measured lung dose to the population of the Belagavi region of India. The outdoor radon levels were measured in different seasons using LR-115 (type II) films fixed in a pin-hole cup detector. The outdoor radon levels in this work were found to be high in summer with values ranging from 11.8 to 27.3 Bq m−3 with a mean value of 20.0 Bq m−3. Lower radon levels were observed in monsoon season and the values range from 3.8 to 15.8 Bq m−3, with a mean value of 10.0 Bq m−3. The potential alpha energy concentration was maximum in summer with a mean value of 3.3 mWLM. The mean annual exposure was found to be 1.4 mWLM and the mean annual inhalation dose was 0.2 mSv y−1. The activity of 226Ra in soils was measured using a NaI (Tl) detector based on gamma ray spectrometer. The 226Ra activity of the study area was in the range of 16.5 to 70.4 Bq kg−1 with a mean value of 32.4 Bq kg−1. The correlation coefficient between the radium content in soil and outdoor radon levels was studied. The present study shows a significant correlation of 0.7, between outdoor radon levels and the radium content in the soil.

A survey of 222Rn concentrations in dwellings of the town of Metsovo in North-western Greece

A radon survey has been carried out of indoor radon concentrations in dwellings ocated in the town of Metsovo, in north-western Greece. To measure indoor radon ioncentrations, CR-39 detectors were installed in randomly selected houses and were exposed :or about 3 months, during summer and winter. Also gamma spectroscopy measurements of he soil's radium content were performed. The indoor radon concentration levels varied from [7.6 to 750.4 Bq m-3, while the radium concentration of soil varied from 4.9 to 97.1 Bq m"3. Seasonal variation of the radon levels and the influence of house features and sou are liscussed.

Radon concentration in water, soil and sediment of Hemavathi River environments

The present paper discusses the systematic study on gamma dose rate, radon exhalation, radium content in soil and sediment and radon concentration in water of Hemavathi River environments. The Gamma dose rate in the air in the study area varied from 98 to 202 nGy h−1 with mean value 145 nGy h−1. The measured dose rate was above the world and Indian average. The mean value of radium activity in soil and sediment was found to be 366.61 and 328.36 mBq kg−1, respectively. The mean value of radon in soil and sediment was found to be 373.90 and 334.90 Bq m−3, respectively. The radon concentration of water ranges from 0.20 to 1.60 kBq m−3 with an average value of 0.67 kBq m−3. The radon in water contributes to dosage in stomach and lungs. The effective doses of radon were calculated and compared with international recommended values. The results show that sediment and water are safe to use for construction and drinking purpose.

An Investigation of Factors Influencing Indoor Radon Concentrations in Dwellings of Northern Rajasthan, India

Abstract An effort has been made to find possible relationships of indoor radon levels with building construction materials, ventilation condition of dwellings and soil gas radon levels. Indoor radon measurements were made using LR-115 type II cellulose nitrate films and the concentrations were estimated by knowing the track density of films through optical microscope. Soil gas radon levels were measured using RAD7, an electronic radon detector manufactured by Durridge Company, USA. This study sheds light on the seasonal indoor radon activities in Rajasthan dwellings. Maximum values of the indoor radon concentration were observed during the winter and minimum during the summer season. Results show that ventilation rate is inversely proportional to radon level. Highest level of indoor radon concentration was found in the mud type dwellings compared with dwellings made of concrete, cement and marble. A positive correlation (R2 = 0.45) between indoor radon and soil gas radon concentration was observed. A weak positive correlation (R2 = 0.22) was observed between soil gas radon concentration and radium content in soil. Indoor radon concentration was found to be associated with the presence of radon concentration in local soil, building material used for roof, floor and walls, type of ventilation conditions and presence of cracks on the walls/floor. Positive correlation between indoor and soil gas radon concentration suggest the large contribution of local soil towards indoor radon.

A comparative study of the indoor radon level with the radon exhalation rate from soil in Alexandria city

The assessment of the radiological risk related to the inhalation of radon and radon its progeny is based mainly on the integrated measurement of radon in both indoor and outdoor environments. The exhalation of radon from the earth's crust and building materials forms the main source of radon in the indoor environment. This study has been undertaken for the purpose of health risk assessment. In this comparative study, the indoor radon level, radium content, radon exhalation rate and concentration of soil radon are measured using the Can Technique. Soil samples were collected simultaneously from different geological formations of the same area for laboratory measurement of the radon exhalation rate. The radon exhalation rate was measured in the laboratory using LR-115 type II plastic track detectors. The indoor radon concentrations in this study area were found to vary from 44±9 to 132±31 Bq m(-3) with an average of 72±29 Bq m(-3). The seasonal variations of the indoor radon reveal the maximum values in the winter and in summer in different dwellings of Alexandria city. The annual effective dose varies from 0.75 to 2.2 mSv with an average value of 1.34 mSv. The radon exhalation rate was found to vary in the ranges 8.31-233.70×10(-3) Bq kg(-1) h(-1), 0.48-15.37 Bq m(-2) h(-1) with an average 47.97×10(-3) Bq kg(-1) h(-1), (3.14 Bq m(-2) h(-1)). The radium content in soil varies from 3.14 to 39.60 Bq kg(-1) with an average of 11.55 Bq kg(-1). The significance of this study is discussed in details from the point of view of radiation protection.

Present and future studies on environmental radioactivity in Japan

In this paper, recent studies on environmental radioactivity are briefly reviewed. Considering the growing dependency on nuclear energy in Asia, emphasis has been given to (14)C cycle at the ground surface including rice paddy fields and to long-range atmospheric transport of natural and anthropogenic radioactive materials. Studies on the dynamic behaviour of (14)C are being carried out and some important experimental results are becoming available for models of (14)C migration in rice paddy. Long-range atmospheric transport models have been improved substantially by using sophisticated physical models and simulation techniques to improve emergency preparedness. Although our knowledge on radon flux distribution in Asia has been improved and radon has become a more reliable atmospheric tracer, we still need more intensive measurements of exhalation flux and atmospheric concentration of radon and radium content in soil.

Determination of indoor radon and soil radioactivity levels in Giresun, Turkey

Indoor radon survey and gamma activity measurements in soil samples were carried out in the Giresun province (Northeastern Turkey). The result of analysis of variance showed a relationship between indoor radon and radium content in soil ( R 2 = 0.54). It was found that indoor radon activity concentration ranged from 52 to 360 Bq m −3 with an average value of 130 Bq m −3. A model built by BEIR VI was used to predict the number of lung cancer deaths due to indoor radon exposure. It was found that indoor radon is responsible for 8% of all lung cancer deaths occurring in this province. 137Cs activity concentration was measured 21 years after the Chernobyl accident. The results showed that 137Cs activity concentration ranged from 41 to 1304 Bq kg −1 with an average value of 307 Bq kg −1. The indoor radon results and the geology of the studied area were discussed. Annual effective doses to the both radionuclides of natural origin and 137Cs were estimated.

Effect of housing factors and surficial uranium on the spatial prediction of residential radon in Iowa

AbstractGrowing epidemiologic evidence suggests that residential radon is an important risk factor for lung cancer. Consequently, public health professionals have expressed interest in characterizing the spatial distribution of radon concentrations in order to identify geographic regions of high exposure. Ambient radon concentrations are a function of geologic features including soil radium content. Indoor radon concentrations can vary based on building characteristics that affect the entry of radon into the building and movement between rooms therein. We present a geostatistical hierarchical Bayesian model for radon that allows for spatial prediction based on geologic data and housing characteristics. Our model is applied to radon data from an epidemiologic study in Iowa that consist of 136 outdoor measurements and 2590 indoor measurements from 614 residential homes. Housing characteristics collected in the Iowa Study are included as predictors in the model. Geologic data in the form of county‐average surficial uranium concentrations from the USGS National Uranium Resource Evaluation project are also considered. A ‘change of support’ approach is implemented to combine the radon measurements, collected at points in space, and the uranium concentrations, averaged over counties, so that point‐source concentrations for the latter are available for the analysis. Estimates of the effect of select housing factors on radon are provided along with spatial maps of predicted radon concentrations in Iowa. Copyright © 2006 John Wiley & Sons, Ltd.

The correlations between Radon in soil gas and its exhalation and concentration in air in the southern part of Syria

The aim of this work is to measure the concentration of the radon ( 222 Rn ) in soil air, 222 Rn exhalation from soil and 222 Rn in outdoor air which may have great influence on 222 Rn levels in houses. 222 Ra activity concentrations were also determined in soil samples. The studied areas are located in southern part of Syria. The common bed rock of this area is black and massive granite which are poor in uranium content [ Jubeli Y.M., 1990. Uranium exploration in Syria. Internal Technical Report, vol. 1 (in English), vol. 2 (in Arabic), SAEC, Damascus; Technoexport (USSR), 1966. In: Ponikarov (Ed.), The Geological Map of Syria Scale: 1:200.000, Ministry of Industry, Damascus, Syria]. Results showed that the maximum measurement in all areas was 32500 Bq m - 3 in soil air with an exhalation rate of 9 Bq m - 2 s - 1 in Darra region and 66.43 Bq m - 3 of radon in open air, with 77 Bq kg - 1 of radium content in soil (Damascus suburb). In addition, correlations between Rn in soil and exhalation of Radon from soil and radon in houses were found in some areas (Sweda and Darra), while, no correlations were found in other studied areas. Moreover, no correlation between radon in houses and radon measurements in soil and in outdoors were found. This was attributed to the methodology used and the influence of building design and inhabitants behavior.

Natural radioactivity measurements in soil samples from Hamirpur district, Himachal Pradesh, India

Radium, thorium and potassium analysis have been made in soil samples collected from some villages of Hamirpur district, Himachal Pradesh, India using gamma ray spectrometry. The work has been undertaken keeping in view the health hazard effects of these radioelements in the environment. The results for radium activity are also compared using track etch technique employing radon alpha method developed by Somogyi (Technical reports series no. 310, vol. 1, IAEA, Vienna, 1990, p. 229). The measurements have been taken using 5″×4″ NaI(Tl) detector. The gamma ray lines of 1.46, 1.76 and 2.62 MeV were employed for potassium, radium and thorium analysis. The results for radium content in soil obtained by gamma ray spectrometry agrees with that determined by the track etch technique. The radium activity in soil samples of Hamirpur district is found to be within the safe limits.

A survey of 222Rn concentrations in dwellings of the town of Metsovo in north-western Greece.

A radon survey has been carried out of indoor radon concentrations in dwellings located in the town of Metsovo, in north-western Greece. To measure indoor radon concentrations, CR-39 detectors were installed in randomly selected houses and were exposed for about 3 mo, during summer and winter. Gamma spectroscopy measurements of the soil's radium content also were performed. The indoor radon concentration levels varied from 17.6 to 750.4 Bq m(-3), while the radium concentration of soil varied from 4.9 to 97.1 Bq m(-3). Seasonal variation of the radon levels and the influence of house features and soil are discussed.

Soil radon levels measured with SSNTD's and the soil radium content

The source of the radon gas 222Rn in the ground air is the soil and the bedrock underneath. The potential radon level in the ground is given by the content of 226Ra in the ground. The presence of 226Ra is in turn dependent on the amount of 238U in the ground, and these two isotopes are not always found to be in equilibrium in a sample of soil or bedrock. Especially if the soil is washed out, the radium content may be reduced. When the soil is the relevant source of the radon gas, it is interesting to look for a possible relation between the radon level and the radium content of the soil. In this paper we report on measurements of soil radon level carried out with SSNTDs at several European sites. Soil samples were collected at these sites and analysed with gamma spectrometry to determine their radium content. A comparison of the different degree of disequilibrium of radon, defined as the ratio between the actual and the secular equilibrium-with-radium soil radon concentration, found at the different sites and depths is presented. The influence on the result of soil type and climate is briefly discussed.

CONCENTRATIONS OF INDOOR AND SOIL RADON IN LITHUANIA/RADONAS GRUNTO ORE IR PATALEOSE LIETUVOJE

Uranium and its daughters including Ra-226 are naturally present in the Earth's crust and other environmental bodies. During decay of Ra-226 radioactive noble gas radon is produced. This gas emanates to the atmosphere from solid matrixes containing Ra-226. It causes a special problem connected with the fact that radon accumulates in the closed spaces of buildings. Increased concentrations of radon indoors in many cases are the significant source of human exposure to ionizing radiation. Radon daughters having been deposited in the airways of human lungs are the source of alpha particles which irradiates the inner surface of airways. Since radiation quality of alpha radiation is high and small volumes of tissues are being irradiated, the influence of indoor radon as a source of ionizing radiation is significant. In order to forecast indoor radon concentrations and to take necessary remedial (in existing buildings) or prevention (in new buildings) measures, the main sources of indoor radon should be known in each country or geographical region. It may be soil, building materials, water and natural gas. It has been determined that the main source of indoor radon in Lithuania is soil. Permanent investigations of radionuclide content of building materials used or manufactured in Lithuania have not revealed any building materials with concentrations of naturally occurring radionuclides exceeding maximum permitted levels determined by the Lithuanian Hygienic Standards HN 40-1994. These investigations are performed by means of gamma spectrometry using the Ge spectrometer by Oxford after sample grinding and drying. A short review of radon risk mapping techniques used in Sweden, USA, Germany and Czech Republic is presented in paper. These techniques may be used for creation of similar technique in Lithuania with corrections connected with local geology. When determining radon risk mainly two parameters should be taken into account: radium content in soil (or radon content in soil air) which is associated with the type of soil and permeability of soil. The Lithuanian system of radon risk determination is not created yet because more detailed data on radon concentrations in soil air should be collected. Data from field measurements of radon concentrations in soil air and concentrations of naturally occurring radionuclides are presented. These measurements were carried out in some potentially important from the point of view of radon risk regions of Lithuania. Concentrations of Ra-226, Th-228 and K-40 in soil have been measured by gamma spectrometer GR-256 by Exploranium on the surface layer (up to 30 cm) of soil. Concentrations of radon in soil have been measured by MARKUS 10 in the depth of 70 cm. The measurements have been performed directly without sampling and sample preparation by digging the detector of Exploranium and pumping rod of MARKUS 10 in the investigated soil. The results indicate that there are some regions in Lithuania with radon concentrations in soil air exceeding 100 kBq/m3. Though radon risk depends on soil permeability these results show that these areas may be identified as areas of medium or even high radon risk. The system for classification of building sites in terms of indoor radon risk should be created in Lithuania in order to follow requirements of Lithuanian radiation protection standards and to keep below determined action levels of indoor radon- 400 Bq/m3 in existing buildings and 200 Bq/m3 in constructed ones. Results of indoor radon measurements are presented as well. The measurements have been performed in 400 randomly selected detached houses during heating season in two lowest permanently used rooms. Duration of one measurement exceeds 3 weeks. E-PERM electrets have been used for this type of measurements. The results show that the average concentration of indoor radon in Lithuania is 55 Bq/m3. In some cases these concentrations exceed the above-mentioned action levels and approach 2000 Bq/m. It shows that indoor radon problems exist in Lithuania as in many other countries. The average concentration of indoor radon in karst region is 125 Bq/m3. It shows that special attention should be paid to such regions because conditions for increased intake of radon to buildings may exist. Indoor radon is one of the main sources of exposure in Lithuania. In some cases it may be the essential source causing tens of milisieverts of annual effective dose. It shows that the problem of indoor radon is important in Lithuania.

CONCENTRATIONS OF INDOOR AND SOIL RADON IN LITHUANIA

Summary Uranium and its daughters including Ra-226 are naturally present in the Earth's crust and other environmental bodies. During decay of Ra-226 radioactive noble gas radon is produced. This gas emanates to the atmosphere from solid matrixes containing Ra-226. It causes a special problem connected with the fact that radon accumulates in the closed spaces of buildings. Increased concentrations of radon indoors in many cases are the significant source of human exposure to ionizing radiation. Radon daughters having been deposited in the airways of human lungs are the source of alpha particles which irradiates the inner surface of airways. Since radiation quality of alpha radiation is high and small volumes of tissues are being irradiated, the influence of indoor radon as a source of ionizing radiation is significant. In order to forecast indoor radon concentrations and to take necessary remedial (in existing buildings) or prevention (in new buildings) measures, the main sources of indoor radon should be known in each country or geographical region. It may be soil, building materials, water and natural gas. It has been determined that the main source of indoor radon in Lithuania is soil. Permanent investigations of radionuclide content of building materials used or manufactured in Lithuania have not revealed any building materials with concentrations of naturally occurring radionuclides exceeding maximum permitted levels determined by the Lithuanian Hygienic Standards HN 40-1994. These investigations are performed by means of gamma spectrometry using the Ge spectrometer by Oxford after sample grinding and drying. A short review of radon risk mapping techniques used in Sweden, USA, Germany and Czech Republic is presented in paper. These techniques may be used for creation of similar technique in Lithuania with corrections connected with local geology. When determining radon risk mainly two parameters should be taken into account: radium content in soil (or radon content in soil air) which is associated with the type of soil and permeability of soil. The Lithuanian system of radon risk determination is not created yet because more detailed data on radon concentrations in soil air should be collected. Data from field measurements of radon concentrations in soil air and concentrations of naturally occurring radionuclides are presented. These measurements were carried out in some potentially important from the point of view of radon risk regions of Lithuania. Concentrations of Ra-226, Th-228 and K-40 in soil have been measured by gamma spectrometer GR-256 by Exploranium on the surface layer (up to 30 cm) of soil. Concentrations of radon in soil have been measured by MARKUS 10 in the depth of 70 cm. The measurements have been performed directly without sampling and sample preparation by digging the detector of Exploranium and pumping rod of MARKUS 10 in the investigated soil. The results indicate that there are some regions in Lithuania with radon concentrations in soil air exceeding 100 kBq/m3. Though radon risk depends on soil permeability these results show that these areas may be identified as areas of medium or even high radon risk. The system for classification of building sites in terms of indoor radon risk should be created in Lithuania in order to follow requirements of Lithuanian radiation protection standards and to keep below determined action levels of indoor radon- 400 Bq/m3 in existing buildings and 200 Bq/m3 in constructed ones. Results of indoor radon measurements are presented as well. The measurements have been performed in 400 randomly selected detached houses during heating season in two lowest permanently used rooms. Duration of one measurement exceeds 3 weeks. E-PERM electrets have been used for this type of measurements. The results show that the average concentration of indoor radon in Lithuania is 55 Bq/m3. In some cases these concentrations exceed the above-mentioned action levels and approach 2000 Bq/m. It shows that indoor radon problems exist in Lithuania as in many other countries. The average concentration of indoor radon in karst region is 125 Bq/m3. It shows that special attention should be paid to such regions because conditions for increased intake of radon to buildings may exist. Indoor radon is one of the main sources of exposure in Lithuania. In some cases it may be the essential source causing tens of milisieverts of annual effective dose. It shows that the problem of indoor radon is important in Lithuania.

Geologic and climatic controls on the radon emanation coefficient

Geologic, pedologic, and climatic factors, including radium content, grain size, siting of radon parents within soil grains or on grain coatings, and soil moisture conditions, determine a soil's emanating power and radon transport characteristics. Data from field studies indicate that soils derived from similar parent rocks in different regions have significantly different emanation coefficients due to the effects of climate on these soil characteristics. An important tool for measuring radon source strength (i.e., radium content) is ground-based and aerial gamma radioactivity measurements. Regional correlations between soil radium content, determined by gamma spectrometry, and soil-gas or indoor radon concentrations can be traced to the influence of climatic and geologic factors on intrinsic permeability and radon emanation coefficients. Data on soil radium content, permeability, and moisture content, when combined with data on emanation coefficients, can form a framework for development of quantitative predictive models for radon generation in rocks and soils.

Regional and local variation of indoor radon and radon source potentials

The upper midwest has been identified as an area with high potential for elevated indoor radon. In Minnesota (MN), substantial spatial variations have been observed in radon and radon sources on both regional and local scales. Different methods for identifying ‘hot spots’ were investigated. Maps generated from existing indoor radon screening measurements averaged over a small area (postal zip code area) correlate well with the average indoor radon concentrations in both high radon and low radon regions within the state. However, a statewide indoor radon map generated from zip code aggregated measurements misses the smaller local hot spots. An intensive study of the spatial variation in Olmsted County, MN, revealed several hot spots within zip code areas. Since many rural regions are poorly represented in indoor radon databases, the usefulness of surrogate measurements, such as the soil radium content, was studied to extend the indoor radon predictions to areas not covered by direct indoor results. Most of the surrogates, including many of those that have been reported as being successful guides in other regions, failed in this region. However, surface 214Bi concentration proved to be a useful, qualitative guide to regional hot spots while radon source potential proved to be a useful, qualitative guide to local hot spots.