Internal Radiation Hazard Research Articles

Depleted uranium residues, NORMs and 137Cs in the coastal zone soil of Musandam Peninsula, Hurmuz strait region, Sultanate of Oman

Musandam peninsula located at one of the most important marine strait overlooking the Arabian/Parisian Gulf. Environmentally, this area is characterized by its primitivistic status and vulnerable to any natural or manmade disturbances. This work presents the second phase of a comprehensive radiation measurement in Musandam Peninsula environment amid to investigating the presences of depleted uranium (DU) residues and assessing the current levels of 226Ra, 228Ra, 40K and 137Cs in surface soil of coastal area. For this purpose, thirty representative soil samples were collected and analyzed for 235U using gamma rays spectrometry and for total U using ICP-OES techniques. Results revealed that the range of isotopic abundance of 235U was (0.70%–0.77%) with an average of 0.72%, confirming the detected uranium is naturally originated from the geological formations of investigated soil. Additionally, the values of Th/U ratios were calculated to be ranged from 0.37 to 1.95 with an average of 1.5 indicating the dominant geological formations are metamorphic sedimentary rocks that contain low levels of Th. The averages of radioactivity levels of NORMs indicated 16.02 Bqkg−1, 7.83 Bqkg−1 and 174.03 Bqkg−1 for 226Ra, 228Ra, and 40K respectively. The average of areal concentrations for 137Cs was 2481.5 Bqm−2 ranges from 1040 Bq/m2 to 9225 Bqm−2. The total external annual effective dose from all measured radionuclides was 23 μSv 237Cs contribution is 1% while 238U, 232Th series and 40K radionuclides contributions are 32%, 28% and 39% respectively. Radium equivalent, external, and internal radiation hazard indices indicate no radiological anomaly.

An Evaluation of Health Hazards Indices of Natural Radioactivity of the Sediments from Eko-Ende Dam, Osun State, Nigeria

This study measured the radioactivity level in the sediments of Eko-Ende Dam in Ifelodun Local Government Area, Osun State, Nigeria and assessed the radiological impact associated. Thirty six (36) sediment samples were collected from three different points within the Dam for a period of 12 months. The samples were analyzed using Gamma Ray Spectrometer. The radiological hazards due to natural radionuclides content, such as absorbed dose rate (DR), annual effective dose rate (AEDE), effective life cancer risk (ELCR), activity utilization index (AUI), internal radiation hazard (Hin) and external radiation hazard (Hex) in the sediment samples were calculated. The calculated radiological parameters were compared with recommended safety limits and internationally approved values. The radium equivalent activity, internal hazard index, annual effective dose equivalent and effective life cancer risk values of the sediment samples were lower than the permissible limit. Thus, the study area might not pose immediate health implications to the general public, but prolonged exposure could lead to radiation related health hazards.

Environmental Radiation Measurement and Assessment of Natural Radioactivity in Soil, Water and Vegetation

Environmental radioactivity is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 (90Sr) and technetium-99 (99Tc), are only found on Earth as a result of human activity, and some, like potassium-40 (40K), are only present due to natural processes, a few isotopes, e.g. tritium (3H), result from both natural processes and human activities. The concentration and location of some natural isotopes, particularly uranium-238 (238U), can be affected by human activity because of the constant exposure of Human beings to radiation caused by terrestrial, extra-terrestrial and anthropogenic radio nuclides, it is necessary to determine and estimate the activity of various radio nuclides in environmental media such as vegetation, soil, and water. In the present research, the activities of 226Ra, 232Th and 40K are measured in soil, vegetation and water samples, collected from Yangdong District, Yangxi County, and Yangjiang County of Guangdong Province, China using an HPGe based gamma spectrometry system. The measured mean activity of 226Ra, 232Th and 40K in soil samples was found to be 31.19 ± 1.2, 47.00 ± 2.30 and 589.31 ± 17.52 Bqkg-1, respectively. The measured mean activity of these radionuclides in all water samples was found to be below minimum detectable activity. The measured mean activity of 226Ra, 232Th and 40K in vegetation samples was 19.92 ± 3.09, 25.36 ± 8.11 and 4982.94 ± 85.68 Bqkg-1, respectively. No anthropogenic 137Cs was detected in these environmental samples. Mean radium equivalent activity (Raeq), external radiation hazard index (Hex), internal radiation hazard index (Hin) and absorbed dose rate (D) for the area under study were determined as 142.92 Bqkg-1, 0.38, 0.47 and 66.47 nGyh-1, respectively. The annual effective dose equivalent (AEDE) varied in the range from 0.03 to 0.12 mSvy-1. It is concluded that the surveyed area do not pose any significant radiological risk to the population and environment.

Radiological Impacts of Natural Radioactivity in Locally Produced Tobacco Products in Oyo State, Nigeria

Radionuclides are found naturally in air, water and soil. They are even found in vegetation, consumer products and in human body. Everyone on the planet is exposed to some background level of ionizing radiation through external exposures that occurs as a result of irradiation, and internal exposures that occurs as a result of ingestion and inhalation. Studies have shown that tobacco contains minute quantities of radioisotopes from uranium and thorium-decay series which are radioactive and carcinogenic. Tobacco product increases both external and internal exposure due to these radioisotopes. In fact, tobacco products have been considered to be one of the most significant causes of lung cancer. Owing to the large-scale consumption of tobacco in Nigeria at the present time, locally produced tobacco products in Nigeria were collected from the market and the naturally-occurring 238U and 232Th decay series, as well as non-series decay 40K in these products were measured using γ-ray spectrometer. The radiological impacts of the radionuclides in these products were assessed from their specific activities. The average values of the absorbed dose rate were 19.72 and 17.59 nGy h-1 for snuff and cigarette products respectively. The average values of the effective doses due to daily inhalation of smoke by consumers from one (1) stick of cigarette and one (1) wrap of snuff products were 66.62 and 592.32 μSv yr-1 respectively. Similarly, the values of the radium equivalent activity index for snuff and cigarette samples were 40.95 and 38.95 Bq kg-1 respectively. Also, the external radiation hazard index was 0.12 and 0.11 for snuff and cigarette samples respectively while the internal radiation hazard index was 0.17 and 0.15 for the two samples respectively. The average excess lifetime cancer risk (× 10-3) values for daily inhalation of smoke from one (1) stick of cigarette and one (1) wrap of snuff were 0.23 and 2.07 × 10-3 respectively. The estimated values of some of these parameters were found to be lower than the recommended limit by UNSCEAR (2000). However, the effective dose poses a serious health risk to addicted consumers of the product and passive smokers in the environment when three (3) or more wraps of snuff and one (1) or more packs of cigarette products are consumed daily. The mean excess lifetime cancer risks values estimated were also much higher than the recommended limits by UNSCEAR (2000). This then makes the risk of suffering cancer and other radiation injuries to be high.

Measurement of Gamma Emitting Radionuclides in Environmental Samples of Talagang Tehsil-District Chakwal

Due to constant exposure of Human beings to radiation caused by terrestrial, extra-terrestrial and anthropogenic radio nuclides, it is necessary to determine/estimate the activity of various radio nuclides in environmental media such as vegetation, soil, and water. In the present research, the activities of 226Ra, 232Th and 40K are measured in soil, vegetation and water samples, collected from Talagang Tehsil-District Chakwal of Pakistan using a HPGe based gamma spectrometry system. The measured mean activity of 226Ra, 232Th and 40K in soil samples was found to be 31.19±1.2, 47.00±2.30 and 589.31±17.52 Bqkg-1, respectively. The measured mean activity of these radionuclides in all water samples was found to be below minimum detectable activity. The measured mean activity of 226Ra, 232Th and 40K in vegetation samples was 19.92±3.09, 25.36±8.11 and 4982.94±85.68 Bqkg-1, respectively. No anthropogenic 137Cs was detected in these environmental samples. Mean radium equivalent activity (Raeq), external radiation hazard index (Hex), internal radiation hazard index (Hin) and absorbed dose rate (D) for the area under study were determined as 142.92 Bqkg-1, 0.38, 0.47 and 66.47 nGyh-1, respectively. The annual effective dose equivalent (AEDE) varied in the range from 0.03 to 0.12 mSv y-1. It is concluded that the surveyed area do not pose any significant radiological risk to the population and environment.

Evaluation of Natural Radioactivity in Marine Sand Deposits from Offshore China

Natural radioactivity is very important for the assessment of the marine sand property and usability. By using gamma spectrometry, the concentration of the natural radionuclides 226Ra, 232Th and 40K have been measured in marine sand deposits from Liaodong Bay (LDB), North Yellow Sea (NYS), Zhoushan area (ZS), Taiwan Shoal (TS) and Pearl River Mouth (PR), offshore China, which are potential marine sand mining areas. The radiation activity equivalent (Raeq), indoor gamma absorbed dose rate (DR), annual effective dose (HR), alpha index (Ia), gamma index (Ig), external radiation hazard index (Hex), internal radiation hazard index (Hin), representative level index (RLI), excess lifetime cancer risk (ELCR) and annual gonadal dose equivalent (AGDE) associated with the natural radionuclides are calculated to assess the radiation hazard of the natural radioactivity in the marine sands offshore China. From the analysis, it is found that these marine sands are safe for the constructions. The Pearson correlation coefficient reveals that the 226Ra distribution in the marine sands offshore China is controlled by the variation of the 40K concentration. Principal component analysis (PCA) yields a two-component representation of the entire data from the marine sands, wherein 98.22% of the total variance is explained. Our results provide good baseline data to expand the database of radioactivity of building materials in China and all over the world.

Determination of Activity Concentrations of the Naturally Occurring Radionuclides and the dose Rates from the Samples Collected from the Chittagong Urea Fertilizer Limited (CUFL), Bangladesh

Abstract: The activity concentrations of 238U, 232Th and 40K have been determined for solid, liquid and product (urea) samples collected from the Chittagong Urea Fertilizer Limited (CUFL), Chittagong, Bangladesh. A total of 15 samples of different kinds were analyzed by using a calibrated high purity germanium (HpGe) detector of relative efficiency of 38%. For solid samples, the mean activity concentrations of 238U, 232Th and 40K have been found 78.67±2.87, 59.74±2.27 and 463.71±9.16 Bq/Kg, respectively. The mean activity concentrations of product samples for the corresponding radionuclide were 73.12±2.83, 74.59±2.32 and 391.58±9.38 Bq/Kg, respectively. For the case of liquid samples, the mean activity concentrations for the same nuclides were 25.09±1.71, 11.34±1.55 and 39.59±1.49 Bq/Kg, respectively. The artificial radionuclide 137Cs was not detected in any of the samples. The mean radiological hazard parameter values of outdoor absorbed dose rate, indoor absorbed dose rate, external radiation hazard, internal radiation hazard, annual effective dose equivalent, radium equivalent activity and representative level index were 95.72±9.04, 114.32±9.11 nGyh-1, 0.530±.05, 0.7±50.05, 113.59±11.41μSvy-1, 199.80±17.41 and 1.390±.14 Bq/Kg respectively, in solid samples. For the product samples, the mean values of the corresponding radiological indices were 97.10+9.71, 117.56+10.32 nGyh-1, 0.57±0.05 , 0.76±0.06, 119.50 ±11.72μSvy-1 , 209.50±17.72 and 1.50±0.14 Bq/Kg, respectively. Also in the liquid samples, the mean values for the corresponding radiological parameters were 18.43±2.69, 22.13±2.77 nGy.h−1, 0.12±0.03 , 0.19±0.05, 23.59± 2.36 μSvy1, 43.65±3.54 and 0.32±0.03 Bq/Kg, respectively. The obtained results of this study show that for some samples the values are lower and for the remaining are higher than the World average values. The mean representative index value is less than unity which confirms that the area is safe for the factory workers and the public nearby. The results can be used as a baseline data for further researchers.

Assessment of Beach sand using Gamma Ray Spectrometer in Thiruvanathapuram District, Kerala of South India

<div><p><em>It is well recognized fact that some areas of the world have anomalously high levels of natural background radiation referred to as high background radiation areas (HBRAs). Typical examples include Yangjiang in China, Rasmar in Iran and In India, part of coastal areas of Kerala and Tamil Nadu fall in this category. It has been established earlier that the cause for this high background is the presence of monazite (thorium). This study focuses on the estimation of the environmental radioactivity levels in the beach sands of </em><em>Thiruvanathapuram district, Kerala. </em><em> </em></p></div><p><em>Using high resolution gamma ray spectroscopy activity concentrations of <sup>40</sup>K, <sup>238</sup>U & <sup>232</sup>Th were estimated. Activity concentrations ranged from 17-154 Bq/kg for <sup>40</sup>K, from 4 to 100 Bq/kg for <sup>238</sup>U and from 6 to 296 Bq/kg for <sup>232</sup>Th.The mean activity concentration values obtained for the radionuclide are below than the world average values reported by the UNSCEAR. Subsequently assessed radiological effects show that the mean radium equivalent activity is 65 Bq/kg. The range of the calculated air exposure rate was between 14.2 to 228.1 nGy/h in both 0 m from the Waves and 10 m from the Waves. The values of external and internal radiation hazard indices are found to be less than unity. Measured natural radioactivity, hazard indices and effective dose received by the population were found to within the recommended limits. This work provides a good baseline data of natural radioactive elements for the sand of the area and its radiological significance. </em></p>

Assessment of radioactivity and radiological hazards in commercial ceramic tiles used in Ife-Central, local government area of Osun State, Nigeria

The activity concentrations of the natural radionuclides (40K, 232Th and 238U) in ceramic tiles use in homes and offices in Ile-Ife were investigated using a NaI (Tl) detector as the detecting device for gamma spectrometry. The gamma absorbed dose rate (DR), radium equivalent activity (Raeq), annual effective dose (Ad), activity concentration index (I), external radiation index (Hex), internal radiation hazard index (Hin), alpha index (Iα), activity concentration index (Iγ), excess lifetime cancer risk (EC), and annual gonadal dose equivalent (AGd) associated with the radionuclides were evaluated in order to assess the radiation hazard of ceramic tiles used in Ile-Ife. The mean activity concentrations of 850, 24, and 128 Bqkg−1 were obtained for 40K, 232Th, and 238U, respectively. These resulted in an annual effective dose that ranged from 0.07 to 0.2 mSvy−1 with a mean value of 0.14 mSvy−1. The results showed that all the calculated radiological parameters are within the recommended safety limit, hence, do not pose significant radiological hazard when used as building materials.In order to determine the similarities and correlations among various samples, all the radiological variables above were subjected to correlation analysis.

Distribution of Natural Radionuclide and Radiation Hazards of Building Materials Used in Assiut, Egypt

The concentration of the naturally occurring radionuclides 226 Ra, 232 Th and 40 K have been measured in Clay (C), gypsum (G), limestone (L), sand (S), brick (B), soil (So), cement (Ce), which are used as building materials in Assiut, Egypt, using gamma spectrometry employing a 3×3 inch scintillation NaI (Tl) detector. The radium equivalent activity (Raeq), indoor gamma absorbed dose rate (D), annual effective dose (An), (AUI), alpha index (Iα), gamma index (Iγ), external radiation hazard index (Hex), internal radiation hazard index (Hin), representative level index (RLI), excess lifetime cancer risk (ELCR) and annual gonadal dose equivalent (AGDE) associated with the natural radionuclides are calculated to assess the radiation hazard of the natural radioactivity in the building materials. Basic statistics (skewness and Kurtosis) and frequency distributions for all radionuclides were used to describe the statistical characteristics of the radionuclide activities.

Assessment of radiological hazard of quarry products from southwest Nigeria

The term “quarry products” comprises different natural rocks with different mineral contents, crushed into various sizes at quarries. The concentrations of the naturally occurring radionuclides 40K, 238U and 232Th in quarry products from southwest Nigeria have been measured using gamma ray spectrometry. The gamma absorbed dose rate (DR), radium equivalent activity (Raeq), annual effective dose (Ad), activity concentration index (I), external radiation index (Hex) and internal radiation hazard index (Hin) associated with the radionuclides are evaluated in order to assess the radiation hazard of quarry products used as building materials. The results showed that a few of the calculated radiological parameters are higher than permissible limit, hence, may pose a radiological hazard when used as building materials.All the radiological variables above were subjected to correlation analysis to determine the similarities and correlations among various samples. The data sets consist of 10 measured variables. The principal component Analysis (PCA) yields a two component representation of the acquired data, in which 93.3% of the total variance is explained.

Measurement of natural radioactivity and evaluation of radiation hazards in coastal sediments of east coast of Tamilnadu using statistical approach

The concentrations of natural radionuclides in the sediments from Thazhankuda (Cuddalore) to Kodiyakkarai of east coast of Tamilnadu have been measured using gamma-ray spectrometry. Using the activity concentrations of these radionuclides, radiological hazard indices were evaluated in order to determine the effects of the sediments. The calculated average value of uranium, thorium and potassium are 3.8, 26.23 and 328.68Bqkg−1, respectively. The radium equivalent activity (Raeq), absorbed dose rate, annual effective dose rate, activity utilization index, internal and external radiation hazard indices were calculated to study the hazardous nature. These values obtained from the coastal sediments were less than the recommended safe and criterion limits given by UNSCEAR. Results of the study could serve as an important baseline radiometric data for future epidemiological studies and monitoring initiatives in the study area. The statistical methods were applied to study the relationship between all the calculated natural radionuclides.

Spatial distribution and lifetime cancer risk due to gamma radioactivity in Yelagiri Hills, Tamilnadu, India

The spatial distribution of natural radioactivity due to uranium, thorium and potassium was investigated in soils from the undisturbed areas in Yelagiri Hills, Tamilnadu, India by Isodose map. The radiological hazards due to natural radionuclides content such as representative level index (RLI), activity utilization index (AUI), excess lifetime cancer risk (ELCR) and internal radiation hazards (Hin) of the soil samples in this area were calculated. The calculated radiological hazard parameters are compared with different countries of the world. The calculated range of ELCR is 0.326 × 10−3 to 1.067 × 10−3 with an average of 0.700 × 10−3 for soils. This average value of ELCR is more twice than the world average (0.290 × 10−3). A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides toward the dose rate. The U/Th concentration ratio in surface soil samples ranged from 0.05 to 1.72 with an average of 0.43 which is more higher (80%) than the world average of 0.26. The application of cluster analysis (CA) and principal component analysis (PCA), coupled with Pearson correlation coefficient analysis, were utilized to analyze the data, identify and clarify between the radiological parameters to know the existing relations. The CA and PCA results showed that the former method yielded three distinctive groups of the soil variables whereas the latter one yielded the number of variables into two factors with 94.47% variance explanation.

Multivariate statistical analysis of radiological data of building materials used in Tiruvannamalai, Tamilnadu, India

Using γ spectrometry, the concentration of the naturally occurring radionuclides 226Ra, 232Th and 40K has been measured in soil, sand, cement, clay and bricks, which are used as building materials in Tiruvannamalai, Tamilnadu, India. The radium equivalent activity (Raeq), the criterion formula (CF), indoor gamma absorbed dose rate (DR), annual effective dose (HR), activity utilization index (AUI), alpha index (Iα), gamma index (Iγ), external radiation hazard index (Hex), internal radiation hazard index (Hin), representative level index (RLI), excess lifetime cancer risk (ELCR) and annual gonadal dose equivalent (AGDE) associated with the natural radionuclides are calculated to assess the radiation hazard of the natural radioactivity in the building materials. From the analysis, it is found that these materials used for the construction of dwellings are safe for the inhabitants.The radiological data were processed using multivariate statistical methods to determine the similarities and correlation among the various samples. The frequency distributions for all radionuclides were analyzed. The data set consisted of 15 measured variables. The Pearson correlation coefficient reveals that the 226Ra distribution in building materials is controlled by the variation of the 40K concentration. Principal component analysis (PCA) yields a two-component representation of the acquired data from the building materials in Tiruvannamalai, wherein 94.9% of the total variance is explained. The resulting dendrogram of hierarchical cluster analysis (HCA) classified the 30 building materials into four major groups using 15 variables.

Radiological Hazards for Marble and Granite Used at Shak El Thouban Industrial Zone in Egypt

The background level of radiation in the natural environment surrounds us at all times. Levels of natural occurring radioactivity in marble and granite used at Shak El Thouban industrial zone in Cairo, Egypt have been investigated using HPGe detector through gamma-ray spectrometry. The activity concentration of radionuclides in the 238U-, 232Th-series and 40K has been determined. The average activity concentration of 238U, 232Th and 40K for marble samples was 23.77 Bq/kg ranged from (10.91 to 45.4), 10.75 Bq/kg ranged from (5.46 to 23.61) and 520.43 Bq/kg ranged from (382.30 to 1132.41), respectively. The 238U, 232Th and 40K activity concentration for granite samples were 54.31 Bq/kg ranged from (12.04 to 106.34), 113.57 Bq/kg ranged from (23.91 to 270.36) and 7867.51 Bq/kg ranged from (2017.60 to 11436.91), respectively. Concerning the radiological risk, the radium equivalent activity, external and internal radiation hazard indices, the radiation level index and absorbed dose rate were evaluated. The mass exhalation rates of 222Rn and emanation coefficient have been also calculated. The mass exhalation rate of radon was found to be from 14.86 to 137.13 and 16.48 to 155.26 μBq/kg·s for marble and granite samples, respectively. The mean values of the specific activity of 226Ra, activity of 238U before and after sealing time and the mass exhalation rate of radon for granite samples are twice that for marble samples. All radiological indices and the mass exhalation rate of radon are lower than the permissible levels for building material in all marble samples, while all granite samples are higher and unsafe and pose a risk to the workers and users of these products due to the emanation of radon that may accumulate by time, especially in closed spaces.

Natural radioactivity of bricks and brick material in the Salihli-Turgutlu area of Turkey

Some of the rocks and soil-originated materials used in building construction are the serious natural radiation sources. Soil-originated bricks and roof-tiles and their raw material in the Salihli-Turgutlu area were tested in situ for natural radiation levels using a gamma-ray spectrometer. The concentrations of the radioelements 40K, 238U and 232Th and air-absorbed radiation rates were measured for soil, raw material heaps, brick and roof-tile stacks and waste brick heaps. The radium-equivalent activity Raeq of the raw material varied between 187.9 and 216.4 Bq kg−1. The external radiation hazard index Hex values ranged between 0.51 and 0.58. For building material and its products, recommended Raeq and Hex levels are 370 Bq kg-1 and 1.0, respectively. On the other hand, both Raeq and Hex values for waste brick heaps, containing broken brick pieces, coal pieces and ash, were higher than the recommended levels, i.e. Raeq values varied from 473.8 to 651.0 Bq kg-1 and Hex values were within the range 1.15–1.76. The annual dose rate and radium-equivalent activity values of the brick and roof-tiles were below the level of criteria. Annual dose rate ranged between 0.42 and 0.62 mSv y−1 and radium equivalent activity was in the range 172.9–245.2 Bq kg−1. The external and internal radiation hazard indices were all below the value of 1.0 for the Salihli-Turgutlu area bricks and roof-tiles. Results of this study were compared with results of previous studies. Natural radiation levels of construction raw material of study area are generally higher than of those of previous studies.

Distribution of Natural Radioactivity in Oil-Derived Lubricants

Oil and gas production processing operations have been known to cause naturally occurring radioactive materials that could lead to internal and external radiation hazards and then a significant radiation dose to the workers. So, in this work, nine oil lubricants samples used on a daily basis were collected from local suppliers in Egypt in order to determine their natural radioactivity. The activity concentrations of the radionuclides were measured using coaxial hyper pure germanium (HPGe) detector system, and the derived doses were evaluated. The average activity concentrations obtained were 0.57 ± 0.04, 2.33 ± 0.39 and 5.44 ± 0.27 Bq·kg−1 for 238U,232Th and 40K, respectively. The absorbed doses were very low ranging from 0.57 to 4.20 nGyh−1.

Low natural terrestrial radioactivity in oil-derived lubricants

Oil and gas production processing operations have been known to involve naturally occurring radioactive materials that lead to internal and external radiation hazards and thus a significant radiation dose to the workers. In this work, samples of nine oil lubricants used on a daily basis were collected from local suppliers in Egypt and analysed to determine their natural radioactivity. The activity concentrations of the radionuclides were measured using a coaxial Hyper Pure Germanium (HPGe) detector system, and derived doses were evaluated. The average activity concentrations obtained were 0.57 ± 0.04, 2.33 ± 0.39 and 5.44 ± 0.27 Bq kg –1 for 238 U, 232 Th and 40 K, respectively. The absorbed doses were very low ranging from 0.57 to 4.20 nGy h –1 .

Measurement of Natural and Artificial Radioactivity in Soil at Some Selected Thanas around the TRIGA Mark-II Research Reactor at AERE, Savar, Dhaka

The activity concentration of natural and fallout radionuclides in the soil at some selected Thanas around the TRIGA Mark-II Research Reactor at Atomic Energy Research Establishment (AERE), Savar, Dhaka were measured by using a high purity germanium detector (HPGe). The study revealed that only natural radionuclides were present in the samples and no trace of any artificial radionuclide was found. The average activity concentration of 238U, 232Th and 40K were found to be 37.8 ± 5.6 Bq.kg-1, 58.2 ± 11.0 Bq.kg-1 and 790.8 ± 153.4 Bq.kg-1 respectively. The radium equivalent activity (Req), absorbed dose rate (D), external radiation hazard index (Hex) and internal radiation hazard index (Hin) were also calculated to find out the probable radiological hazard of the natural radioactivity.

Measurement of natural radioactivity in common building materials used in Tiruvannamalai, Tamilnadu, India

The radioactivity of some building materials used in Tiruvannamali City has been measured using a NaI (Tl) detector based gamma ray spectrometer. The distribution of natural occurring radionuclides ( 226 Ra, 232 Th and 40 K) in the building materials was studied. The radium equivalent activity (Ra eq ), the activity utilization index (I), external hazard index (H ex ) and internal radiation hazard index (H in ) associated with the natural radionuclide are calculated to assess the radiation hazard of the natural radioactivity in the building materials. The present work shows that the natural radioactivity levels in the building construction materials used in Tiruvannmalai City is well below the acceptable limits. From the analysis, it was found that these materials may be safely used as construction materials and do not pose significant radiation hazards.