Natural Radioactivity Levels Research Articles

Determination of natural radioactivity levels in Kars- city center, Turkey

The objective of this study is to determine the distribution of natural radionuclides in surface soils in the Karscity center, Turkey. The activity concentrations of 238U, 232 Th, 40 K and 137Cs in 38 soil samples collected from the study area were measured through NaI(Tl) gamma spectrometry. The average activities of the samples were determined to be 47.8, 31.2 and 536 Bqkg-1 for the natural radionuclides 226Ra (238U), 232Th, 40K, respectively, and 18 Bqkg-1 for the fission product 137Cs. When the present results are compared with the data available for other cities in Turkey, the soil radioactivity concentrations obtained in this study indicate that the region has a background radiation level within natural limits but the measured average activity of 40K depending on soil texture is slightly higher than the other parts of country

Analysis of Radioactivity Content in Sediment, Water and Fish Collected From Rajakkamangalam Estury of Kanyakumari District in Tamilnadu, India

The natural radioactivity due to Uranium, Thorium and Potassium in soil, and water contributes to the radiation dose received by human beings significantly. For assessing the environmental radiological impact to the public it is essential to evaluate the activity levels of these nuclides. Results of the gamma ray spectrometric measurements, carried out for natural radioactivity levels due to

Baseline Assessment of dose due to Natural Radionuclides in soils of coastal regions of Kanyakumari district in Tamil Nadu, India

The natural radioactivity due to uranium, Thorium and potassium in soil contributes to the radiation dose received by human beings significantly. Gamma ray spectrometric measurements carried out for the natural radioactivity levels due to 226 Ra, 232 Th and 40 K in beach sand samples around the coast of Kanyakumari district were analyzed. For assessing the environmental radiological impact to public it is essential to evaluate the activity levels of these radionuclides. The absorbed dose rate due to natural radionuclides was also calculated and the results are reported in this paper. The total annual effective dose of the study area founds to vary between 0.94 mSv to 2.23 mSv. This study provides a baseline data of radioactivity background levels in the coastal regions of Kanyakumari district from Muttom to Midalam and will be useful to assess any changes in the radioactive background levels.

Role of light and heavy minerals on natural radioactivity level of high background radiation area, Kerala, India

Natural radionuclides (238U, 232Th and 40K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. Activity concentrations (238U and 232Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the 238U and 232Th concentrations. Whereas, light mineral (calcite) controls the 40K concentration. In addition to the heavy minerals, clay content also induces the important radioactive variables.

Natural and artificial radioactivity levels and hazards of soils in the Kücük Menderes Basin, Turkey

In this study, natural and artificial radionuclide activity concentrations in surface soils of Kucuk Menderes Basin have been measured using gamma spectroscopy. The soil samples were collected from agricultural lands in the Kucuk Menderes Basin in Turkey. The activity concentrations of 226Ra, 232Th, 40K and 137Cs in the soils were found to be range of 12.63 ± 2.28–72.51 ± 11.23, 11.45 ± 2.4–58.12 ± 4.76, 234.8 ± 14.85–1058.52 ± 24 Bq kg−1 dw and 2.31 ± 0.18–7.75 ± 1.14 Bq kg−1, respectively. The natural gamma radioactivity of the terrestrial radionuclides in soil samples and the gamma absorbed dose rate, the annual effective dose equivalent, the radium equivalent activity, the external hazard index, were calculated and compared with the international recommended values.

Reference levels of natural radioactivity and 137Cs in and around the surface soils of Kestanbol pluton in Ezine region of Çanakkale province, Turkey

The aim of the study was to conduct a systematic investigation on the natural gamma emitting radionuclides (226Ra, 232Th and 40K) as well as 137Cs in the surface soils from Kestanbol/Ezine plutonic area in Çanakkale province as part of the environmental monitoring program on radiologic impact of the granitoid areas in Western Anatolia. The activity measurements of the gamma emitters in the surface soil samples collected from 52 sites distributed all over the region has been carried out, by means of HPGe gamma-ray spectrometry system. The activity concentrations of the relevant radionuclides in the soil samples appeared in the ranges as follows: 226Ra was 20–521 Bq kg−1; 232Th, 11–499 Bq kg−1and; 40K, 126–3181 Bq kg−1, yet the 137Cs was much lower than 20 Bq kg−1at most. Furthermore, based on the available data, the radiation hazard parameters associated with the surveyed soils were calculated. The present data also allowed evaluation of some correlations that may exist in the investigated natural radionuclides of the soil samples from the plutonic area in Çanakkale province. It is concluded from the above that the concerned region did not lead to any significant radiological exposure to the environment.

Screening tools to limit the use of building materials with enhanced/elevated levels of natural radioactivity: Analysis and application of index criteria

Until now various methods have been developed in several countries to evaluate and classify building materials on the basis of their natural radioactivity. Some of them also account for the contribution of radon to the annual effective dose. In this paper the authors review these methods and apply some of them to the contents of a database of natural radioactivity of building materials in the European Union, that was established by the authors. Based on the activity concentration index introduced by the EC Radiation Protection 112 guidance, IRP112, a new index is also proposed, that accounts for the radon contribution to the effective dose indoors. The results obtained with different indexes are compared in order to evaluate the impact of the new Basic Safety Standards Directive implementation in the EU Member States, particularly in Countries where radioactivity in building materials is already regulated. Moreover, some non EU screening tools were considered to provide suggestions for possible future improvements of the EC IRP112.

Natural radioactivity levels of geothermal waters and their influence on soil and agricultural activities

All over the world geothermal sources are used for different purposes. The contents of these waters are important to understand positive/negative effects on human life. In this study, natural radioactivity concentrations of geothermal waters were investigated to evaluate the effect on soils and agricultural activities. Geothermal water samples were collected from the Seferihisar Geothermal Region, and the radon and radium concentrations of these waters were analysed using a collector chamber method. Also soil samples, which are irrigated with geothermal waters, were collected from the surroundings of geothermal areas, and natural radioactivity concentrations of collected samples (U, Th and K) were determined using an NaI(Tl) detector system. The activity concentrations of radon and radium were found to be 0.6-6.0 and 0.1-1.0 Bq l(-1), respectively. Generally, the obtained results are not higher compared with the geothermal waters of the world. The activity concentrations in soils were found to be in the range of 3.3-120.3 Bq kg(-1) for (226)Ra (eU), 0.3-108.5 Bq kg(-1) for (232)Th (eTh), 116.0-850.0 Bq kg(-1) for (40)K (% K).

Micro-zoning of the natural radioactivity levels and seismic velocities of potential residential areas in volcanic fields: The case of Isparta (Turkey)

Abstract This study involved the analysis of the locations with the lowest earthquake risk in the Isparta province of Turkey and the radiological properties of these locations. The most convenient residential areas in the region in terms of radiology and earthquake risk were identified. The radiological characteristics of soil are an important factor in the evaluation of residential areas. Gamma ray spectrometry and multi-source seismic refraction methods were used to conduct radioactive and seismic measurements. The measured 238 U, 232 Th and 40 K activity concentrations were used to calculate the absorbed gamma dose rate, the annual effective dose rate, the radium equivalent and the external hazard index of the environment to estimate the radiological risk of natural radioactivity. The compressional and shear wave velocities were calculated based on the results of multi-source seismic refraction. The calculated parameters were used to generate micro-zone maps. The shear wave velocity was used to analyze the stiffness of looseness of the soil. The radiological risks of the area were determined. Both the seismic and radiological hazards were considered in determining the appropriate areas for residential development. In the results of this study, the best location for residential development was demonstrated to be on limestone, and the worst location was determined to be on alluvium.

Radiation impact assessment of naturally occurring radionuclides and magnetic mineral studies of Bharathapuzha river sediments, South India

The natural radioactivity levels and magnetic measurements in sediment samples of Bharathapuzha river for the first time have been determined. Bottom sediments from 33 locations were collected to determine 226Ra, 232Th and 40K using a HPGe detector based on the high-resolution gamma spectrometry system, and magnetic susceptibility by using Bartington MS2 magnetic susceptibility meter. The calculated activity concentrations of 226Ra, 232Th and 40K have been found to vary from 21.21 to 66.03 Bq kg−1, 33.49 to 93.10 Bq kg−1 and 232.25 to 899.66 Bq kg−1, respectively. The results have been compared with worldwide recommended values and also with radioactivity measurements in river sediments of India and other parts of the world. The air-absorbed dose rate, indoor and outdoor annual effective dose rates and radium equivalent activity are calculated with an aim to access the radiation hazards arising due to the use of these materials in the construction of buildings and their mean values obtained are 74.83 nGy h−1, 367.08 μSv y−1, 91.77 μSv y−1 and 157.09 Bq kg−1, respectively. The mass-specific magnetic susceptibility values ranged widely from 35.4 to 2,160.5 × 10−8 m3 kg−1 and compared with other rivers in South India. Multivariate statistical analyses were performed to describe the magnetic and radioactivity relevance of the different groups of samples. The data obtained in the present study may be useful for radiological and magnetic mapping of the study area in the future.

DETERMINATION OF RADIONUCLIDES IN SOIL FROM BARENDRA REGION IN RAJSHAHI AND MINING REGION IN DINAJPUR

The level of natural radioactivity in soil samples calculated from the Barendra region, Rajshahi and the Mining region, Dinajpur was measured and the radiological hazard parameters in both the regions were estimated. The activity concentrations of naturally occurring radioactive materials in the 238U and 232Th decay chains and in 40K were determined by means of a gamma-ray spectrometry system using an HPGe detector in a low background configuration at Atomic Energy Centre, Dhaka. The activity concentrations of 238U, 232Th and 40K found in the present study are compared with the reported values of the Northern region and other districts of Bangladesh and those of other countries of the world. Radiological hazard parameters of the two regions were estimated and compared with the world averages. The natural radioactivity in the Barendra and Mining region poses no threat to general public there. Artificial radionuclide 137Cs was not found in the soil samples studied. (Keywords: Radioactivity, HPGe Detector, Soil, Barendra and Mining region, Radiological hazard parameters)

Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia

The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.

Function of minerals in the natural radioactivity level of Vaigai River sediments, Tamilnadu, India – Spectroscopical approach

Using Gamma ray and Fourier Transform Infrared (FTIR) spectroscopic techniques, level of natural radioactivity (238U, 232Th and 40K) and mineralogical characterization of Vaigai River sediments have been analyzed with the view of evaluating the radiation risk and its relation to available minerals. Different radiological parameters are calculated to know the entire radiological characterization. The average of activity concentrations and all radiological parameters are lower than the recommended safety limit. However, some sites are having higher radioactivity values than the safety limit. From the FTIR spectroscopic technique, the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, gibbsite, calcite, montmorillonite and organic carbon are identified and they are characterized. The extinction co-efficient values are calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index is calculated to know the crystalline nature of quartz and the result indicates that the presence of ordered crystalline quartz in the present sediment. The role of minerals in the level of radioactivity is assessed by multivariate statistical analysis (Pearson’s correlation and Cluster analysis). The statistical analysis confirms that the clay mineral kaolinite is the major factor than other major minerals to induce the important radioactivity variables such as absorbed dose rate and concentrations of 232Th and 238U.

Assessment of natural radioactivity levels and associated dose rates in soil samples from Northern Rajasthan, India

The analysis of naturally occurring radionuclides ((226)Ra, (232)Th and (40)K) has been carried out in 40 soil samples collected from four districts of the Northern Rajasthan, India using gamma-ray spectrometry with an NaI(Tl) detector. The activity concentrations of the samples range from 38±9 to 65±11 Bq kg(-1) with a mean value of 52 Bq kg(-1) for (226)Ra, from 8±8 to 32±9 Bq kg(-1) with a mean value of 19 Bq kg(-1) for (232)Th and from 929±185 to 1894±249 Bq kg(-1) with a mean value of 1627 Bq kg(-1) for (40)K. The measured activity concentration of (226)Ra and (40)K in soil was higher and for (232)Th was lower than the worldwide range. Radium equivalent activities were calculated for the soil samples to assess the radiation hazards arising due to the use of these soils in the construction of buildings. The calculated average radium equivalent activity was 205±20 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1) by the Organization for Economic Cooperation and Development. The total absorbed dose rate calculated from the activity concentration of (226)Ra, (232)Th and (40)K ranges from 77 to 123 nGy h(-1) with an average value of 103 nGy h(-1). The mean external (Hex) and internal hazard indices (Hin) for the area under study were determined to be 0.55 and 0.69, respectively. The corresponding average annual effective dose was found to be 0.63 mSv.

Assessment of natural and anthropogenic radioactivity levels in soils, rocks and water in the vicinity of Chirano Gold Mine in Ghana

Studies have been carried out within and around the operational area of the Chirano Gold Mine Ltd of Ghana to ascertain the baseline radioactivity levels of naturally occurring radioactive materials as well as artificial radionuclides in the surface and underground mines. The analysis was carried out by using gamma spectrometry to quantify the radionuclides of interest, namely (238)U, (232)Th, (137)Cs and (40)K in soil, ore, waste rock and water samples. The average activity concentrations of (238)U, (232)Th, (40)K and (137)Cs in the soil/rock samples were 9.79±5.39, 9.18±7.06, 237.40±144.34 and 0.64±0.57 Bq kg(-1), respectively. For the water samples, the average activity concentrations were 0.86±0.67, 0.97±1.33 and 9.05±10.45 Bq l(-1) for (226)Ra, (232)Th and (40)K, respectively. The total annual effective dose to the public was estimated to be 0.13 mSv, which is below the International Commission on Radiological Protection recommended level of 1 mSv for public exposure control. The study also assessed the elemental concentrations of U, Th and K in the soil/rock samples from the gold mine and surrounding communities. The average concentrations of the U, Th and K were 0.82±0.48, 2.18±1.77 µg g(-1) and 0.77±0.47 %, respectively. The concentrations of U, Th and K were variable in soil and rock samples taken from different locations in the study area with values varying in the range 0.28-2.21, 0.24-6.50 µg g(-1) and 0.28-1.87 %, respectively. The concentrations of U, Th and K are far lower than the world average values but comparable with the range of similar studies for different countries. The concentration values of gross-alpha and gross-beta for all the water samples were below the Ghana Standards Authority and World Health Organisation recommended guideline values for drinking water quality. The results obtained in this study also show that radiation levels are within the natural background radiation levels found in the literature and compare well with those of similar studies for other countries including Ghana.

Measurement of natural radioactivity in soil from Peshawar basin of Pakistan

Natural radioactivity in the environment may change with time due to human activities, chemical and biological changes. From the view of radiation risk to population, the knowledge of natural radioactivity levels and the measurement of collective radiation dose received by the population is very vital. Radiological constraints on soil of thickly populated Peshawar basin in northern Pakistan were assessed through radiometric assay. Soil samples collected from different locations of four districts of this basin were analysed using an HPGe gamma spectrometer. Activity concentrations of 40K, 226Ra and 232Th in these samples was 648 ± 121 (421–996), 45 ± 7 (32–60) and 59 ± 7 (46–72) Bq kg−1, respectively that followed lognormal distribution. The average concentrations of primordial radionuclides were found to be higher than that reported for the worldwide soil. Radium equivalent activity and gamma index derived from these activity concentrations were lesser than their respective limits. The average absorbed dose rate and the annual effective dose for both indoor and outdoor cases were found to be higher than the values given in the UNSCEAR 2000 report. The results of the present study were compared with those for other locations of Pakistan along with that for the world. The radiological impact of the measured data was evaluated using hazard assessment models. A thoughtful discussion of the above mentioned evaluation is also given.

Natural radioactivity and radiation index of the major plutonic bodies in Greece

The natural radioactivity of the major plutonic bodies in Greece, as well as the assessment of any potential health hazard due to their usage as decorative building materials is studied. One hundred and twenty one samples from every major plutonic body in Greece, including various rock-types from gabbro to granite, have been measured for their natural radioactivity using γ-spectrometry methodology. According to the experimental results, the natural radioactivity levels were ranged up to 315 Bq kg−1 for 226Ra, up to 376 Bq kg−1 for 232Th and up to 1632 Bq kg−1 for 40K, with arithmetic mean values and standard deviations of 74 (±51), 85 (±54) and 881 (±331) Bq kg−1 respectively, which are below the international representative mean values for granite stones. The excess on the effective dose received annually indoors due to granite tiles usage is estimated considering a standard room model where granite tiles with 1.5 cm in thickness cover only the floor of the room. The increment on the external γ-radiation effective dose rate shows a Gaussian distribution well dispersed below 0.3 mSv y−1, presenting a mean value of 0.14 (±0.06) mSv y−1. In case of the internal α-radiation a log-normal distribution is appeared scattering below 0.5 mSv y−1 with a mean value 0.19 (±0.13) mSv y−1, for a well-ventilated living environment. In case of a poor-ventilated room the increment on internal effective dose rate is estimated with a mean value 0.27 (±0.19) mSv y−1 scattering below 0.8 mSv y−1. The majority of the samples increase the external as well as the internal dose less than 30% of the maximum permitted limit of the effective dose rate. Therefore, at least from radiological point of view, the plutonic rocks of Greece could be safely used as decorative building materials.

Study of Natural Radioactivity of Slovak Cements

Building materials belongs to the sources causing direct radiation exposure, therefore the natural radionuclide content of building materials is necessary to be still discussed over the world. Cements cause direct radiation exposure because of their radium (Ra), thorium (Th) and potassium (K) content. Like other construction materials, the natural level of radioactivity in cement gives rise to external and internal indoor exposure. This work is focused on the assessment of natural radioactivity of cements commonly used in the Slovak Republic. The cement samples of CEM I, CEM II, CEM III and CEM V types from the significant Slovak cement producers were analyzed in the experiment. The samples were tested for the radionuclides content by using gamma spectroscopic measurements. The radionuclides activity in the Portland cements ranged from 5.8 – 21.6 Bq kg, 16.0 – 38.23 Bq kg and 52.0 – 733.6 Bq kg for Ra, Th and K, respectively. The measured radionuclides content was compared to the specific requirements in relation to the Slovak eco-labelling process. The index of mass activity of natural radionuclides (gamma index) in cements was calculated in the range from 0.122 – 0.484.

Assessment of natural radioactivity levels in soil samples from some areas in Assiut, Egypt

The natural radioactivity of soil samples from Assiut city, Egypt, was studied. The activity concentrations of 28 samples were measured with a NaI(Tl) detector. The radioactivity concentrations of (226)Ra, (232)Th, and (40)K showed large variations, so the results were classified into two groups (A and B) to facilitate the interpretation of the results. Group A represents samples collected from different locations in Assiut and characterized by low activity concentrations with average values of 46.15 ± 9.69, 30.57 ± 4.90, and 553.14 ± 23.19 for (226)Ra, (232)Th, and (40)K, respectively. Group B represents samples mainly collected from the area around Assiut Thermal Power Plant and characterized by very high activity concentrations with average values of 3,803 ± 145, 1,782 ± 98, and 1,377 ± 78 for (226)Ra, (232)Th, and (40)K, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose rate (E), the external hazard index (H ex), and the annual gonadal dose equivalent (AGDE) have been calculated and compared with the internationally approved values. For group A, the calculated averages of these parameters are in good agreement with the international recommended values except for the absorbed dose rate and the AGDE values which are slightly higher than the international recommended values. However, for group B, all obtained averages of these parameters are much higher by several orders of magnitude than the international recommended values. The present work provides a background of radioactivity concentrations in the soil of Assiut.

Natural radioactivity study in soil samples of South Konkan, Maharashtra, India

This study assesses the level of natural radioactivity due to radionuclides, ²³⁸U, ²³²Th and ⁴⁰K, in 50 soil samples collected from South Konkan, Maharashtra, India. The mean activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K are 44.97 ± 1.22 Bq kg⁻¹, 59.70 ± 2.17 Bq kg⁻¹ and 217.51 ± 8.75 Bq kg⁻¹, respectively, measured from all the soil samples studied. The good correlation between activity concentration of U-238 and Th-232; U-238 and K-40 as well as between activity concentration of Th-232 and K-40 was observed. The average calculated absorbed dose rate in air (68.08 nGy h⁻¹) was found to be higher than the world average of 57 nGy h⁻¹ (UNSCEAR 2000). Radium equivalent activity for all the villages was found to be lower than the worldwide value. The values of external hazard index and internal hazard index determined from all the soil samples were found to be within recommended limit. The calculated average annual effective dose was found to be 0.42 mSv y⁻¹, and it is lower than the worldwide value of 0.46 mSv y⁻¹.The annual effective dose values calculated from present study were comparable with previous studies carried out in other countries and in India. The data established from the study can be useful as baseline information on natural radioactivity in South Konkan, Maharashtra, India.