Studies on radionuclides around Hemavathi river basin of Karnataka,India

The activity concentration and total annual effective dose of the terrestrial naturally occurring radionuclides (²³²Th, ²²⁶Ra and ⁴⁰K) were measured in soil and rock samples collected from various locations of Hemavathi river basin in Karnataka, using HPGe detector. The results revealed that activity concentration of radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in the soil had geometrical mean values of 16.7 ± 0.6, 33.9 ± 1.2 and 359.9 ± 9.2 Bq kg^?1, respectively. In rock samples activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K had geometrical mean values of 20.2 ± 0.7, 18.0 ± 0.9 and 276 ± 9.6 Bq kg^?1, respectively. The external Hazard index and indoor hazard index were found to be within safety limits prescribed by European commission 1999 report.     

Terrestrial absorbed dose rate measurement in the Jhangar valley of Pakistan

Specific activity of natural radionuclides; ²²⁶Ra, ²³²Th and ⁴⁰K were measured in the agricultural soil of eastern salt range of Pakistan using gamma ray spectrometry. The soil samples were collected within the ploughing region (up to 12 cm depth) and processed before analysis. The average specific activities of different radionuclides in the dry mass of soil samples were: ⁴⁰K, (666 Bq/kg), ²²⁶Ra (51 Bq/kg), and ²³²Th (59 Bq/kg). The average outdoor terrestrial absorbed dose rate in air from gamma radiation one meter above ground surface was found to be 93 nGy/h.     

Measurement of soil radioactivity levels and radiation hazard assessment in mid Rechna interfluvial region,Pakistan

Radioactivity levels in soil samples, collected from mid Rechna interfluvial region, Pakistan have been estimated by using gamma ray spectrometric technique. ²²⁶Ra, ²³²Th, the primordial radionuclide ⁴⁰K and the artificial radionuclide ¹³⁷Cs have been measured in the soil of the study area. The mean radioactivity levels of ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs were found to be 49.0 ± 1.6, 62.4 ± 3.2, 670.6 ± 33.9 and 3.5 ± 0.4 Bq kg⁻¹ respectively. The mean radium equivalent activity (Ra_eq), outdoor radiation hazard index (H _out), indoor radiation hazard index (H _in) and terrestrial absorbed dose rate for the area under study were determined as 189.9 ± 8.8 Bq kg⁻¹, 0.51, 0.65 and 70.1 nGy h⁻¹ respectively. The annual effective dose to the public was estimated to be 0.43 mSv. The measured values are comparable with other global radioactivity measurements and are found to be safe for public and environment.     

Levels and effects of natural radionuclides in soil samples of Garhwal Himalaya

Distribution of natural radionuclide gives significant parameter to assess the presence of gamma radioactivity and its radiological effect in our environment. Natural radionuclides are present in the form of ²²⁶Ra, ²³²Th and ⁴⁰K in soil, rocks, water, air, and building materials. Distribution of natural radionuclides depends on the type of minerals present in the soil and rocks. For this purpose gamma spectrometer is used as tool for finding the concentration of these radionuclides. The activity concentration of naturally occurring radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in these soil samples were found to vary from of 8 ± 1 Bq/kg to 50 ± 10 Bq/kg with an average 20 Bq/kg, 7 ± 1–88 ± 16 Bq/kg with an Average 26 Bq/kg and 115 ± 18–885 ± 132 Bq/kg with an average 329 Bq/kg, respectively. In this paper, we are presenting the radiological effect due to distribution of natural radionuclide present in soil of Garhwal Himalaya.     

Measurement of naturally occurring/fallout radioactive elements and assessment of annual effective dose in soil samples collected from four districts of the Punjab Province,Pakistan

Soil samples were collected from different localities of districts Jhelum, Chakwal, Rawalpindi and Attock, Punjab Province, Pakistan with an aim to measure naturally occurring radionuclides, namely ²²⁶Ra, ²³²Th, ⁴⁰K and fallout ¹³⁷Cs radionuclide using a P-type coaxial high purity germanium (HPGe) γ-ray spectrometer. Measured specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K in these soil samples ranged from 26.02 ± 7.11 to 93.54 ± 8.13 Bq kg⁻¹, 29.34 ± 2.58 to 114.41 ± 2.80 Bq kg⁻¹ and 348.15 ± 3.20 to 752.98 ± 4.20 Bq kg⁻¹, respectively. Activity due to ¹³⁷Cs was observed in some locations which ranged from 0.4 ± 0.2 to 7.8 ± 0.3 Bq kg⁻¹. From the measured activity concentrations, radium equivalent activity concentrations were determined followed by calculations of mean absorbed dose rate and mean annual effective dose for the inhabitants of the studied area. The mean radium equivalent activity, internal and external hazard indices values came out to be 179.26 ± 11.93 Bq kg⁻¹, 0.64 ± 0.05 and 0.48 ± 0.03, respectively. Indoors and outdoor average annual effective dose values were found to be 0.42 ± 0.03 and 0.10 ± 0.01 mSv, respectively. Present data have been compared with the published data for other parts of the world and found to be safe for public and environment.     

Natural radioactivity in surface marine sediments near the shore of Vizag, South East India and associated radiological risk

Naturally occurring radioactive materials were determined in surface sediments from the marine environment near the shore of Vizag in the South eastern part of India using gamma spectrometry technique. The mean activity concentration was found to be 36 ± 11, 34 ± 15, 75 ± 38 and 782 ± 223 Bq/kg and ranged from 19 to 48 Bq/kg, 11 to 57 Bq/kg, 31 to 145 Bq/kg and 363 to 1,024 Bq/kg for ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The mean radium equivalent activity, external hazard index, air absorbed gamma dose rate and annual effective dose equivalent are 203 ± 62 Bq/kg, 0.6 ± 0.2, 94 ± 27 nGy/h and 0.12 ± 0.03 mSv/year respectively. This data will serve as the baseline level for naturally occurring radionuclides in the study area and will be useful for tracking and assessing any pollution inventory in the environment of this region.     

Preliminary studies on 226Ra, 228Ra, 228Th and 40K concentrations in foodstuffs consumed by inhabitants of Accra metropolitan area, Ghana

Knowledge of radioactivity levels in human diet is of particular concern for the estimation of possible radiological hazards to human health. However, very few surveys of radioactivity in food have been conducted in Ghana. The natural radionuclides ²²⁶Ra, ²²⁸Ra, ²²⁸Th and ⁴⁰K were measured in the foodstuffs using gamma ray spectrometry. All samples were found to contain high ⁴⁰K content in the range 87.77?C368.50?Bq?kg^?1. The maximum concentration of ²²⁸Th and ⁴⁰K were found in cassava to be 14.93?±?3.86 and 368.50?±?19.20?Bq?kg^?1, respectively. The total annual committed effective dose was estimated to be 4.64?mSv. The daily intake of radionuclides from food consumption reveals that cassava and plantain are the highest contributors, while millet is the lowest. The daily radionuclide intake from the foodstuffs consumed by the general public was 411.32?Bq and the daily internal dose resulting from ingestion of the radionuclides in the foodstuffs was 0.01?mSv. The radionuclide concentrations were comparable with those reported from other countries.     

Concentration of natural radionuclides in and around Padubidri on the coastal Karnataka,India

The activity concentrations of natural radionuclides viz. ²³²Th, ²²⁶Ra and ⁴⁰K were measured in soil samples of Padubidri on the coastal Karnataka, the site for the proposed coal based thermal power station, using gamma-ray spectrometry to establish a baseline data on radioactivity levels in the environment of the region. The activity concentration of ²³²Th varies in the range of 38.5–115.5 Bq·kg⁻¹ with a mean value of 66.0 Bq·kg⁻¹, the activity concentration of ²²⁶Ra varies in the range 35.3–72.5 Bq·kg⁻¹ with a mean value of 53.5 Bq·kg⁻¹ and that of ⁴⁰K varies in the range of 307.5–550.9 Bq·kg⁻¹ with a mean value of 419.3 Bq·kg⁻¹. The radium equivalent activity varies in the range of 140.0–242.9 Bq·kg⁻¹ with a mean value of 180.2 Bq·kg⁻¹. The correlation between ²²⁶Ra and ⁴⁰K, ²³²Th and ⁴⁰K and ²²⁶Ra and ²³²Th was studied from the results of the concentration of these naturally occurring radionuclides. The calculated dose rates in air due to these naturally occurring radionuclides varies in the range of 66.0–110.0 nGy·h⁻¹ with a mean dose rate of 83.1 nGy·h⁻¹.     

Radioactivity mapping of north western areas of Pakistan

Summary A systematic study of natural and fall-out radionuclides was carried out with the environmental samples of soil, vegetation and water from some regions of North West Frontier Province (NWFP) of Pakistan. The pretreatment of the samples was performed in the laboratory using IAEA recommended methods. The analysis of gamma-emitters such as ⁴⁰K, ²²⁶Ra, ²³² Th and ¹³⁷Cs was performed with a high purity germanium detector (HPGe). For the determination of ⁹⁰Sr, a liquid scintillation counting system was used. The average specific activities of ⁴⁰K, ²²⁶Ra, ²³² Th and ¹³⁷Cs have been found to be 307±101 Bq ^. kg^-1, 10.2±3 Bq ^. kg^-1, 24±6 Bq ^. kg^-1 and 2.8±1.3 Bq ^. kg^-1, respectively, in soil samples. Vegetation samples have smaller values of specific activities and even the analysis of water samples showed values less than LLD for earlier reported radionuclides. Other parameters like hazard indices, radium equivalent activities, absorbed dose rates and effective dose equivalents have also been determined. All these parameters have values less than their respective limiting values representing that the surveyed areas have no significant hazard from health point of view. Analysis of ⁹⁰Sr for all the samples showed results below LLD. The present study provides a general background of the detectable radionuclides for the surveyed areas that will be helpful in any radiological emergency.     

Radiometric analysis of rock and soil samples of Leepa Valley; Azad Kashmir, Pakistan

In this article, we present results obtained from a radiometric survey that was conducted in the Leepa Valley of Azad Jammu & Kashmir, Pakistan. The purpose of current study is to appraise the radioactivity levels and the associated health hazards due to the terrestrial radionuclide in soil and rock samples. In this regard, 16 soil and 17 rock samples were collected from different locations of the Leepa Valley. After processing the samples, activity concentrations of primordial (²³²Th, ²²⁶Ra and ⁴⁰K) and anthropogenic (¹³⁷Cs) radionuclides were determined using a P-type coaxial high purity germanium detector. From the results obtained the mean activity concentrations of radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in the soil samples were found to be 31.25 ± 0.46, 44.1 ± 1.07 and 575 ± 8.89 Bq kg^?1 respectively. Whilst, in rock samples ²²⁶Ra, ²³²Th and ⁴⁰K mean activities were found as 28.46 ± 0.45, 48.63 ± 1.12 and 666.7 ± 9.39 Bq kg^?1, respectively. The ¹³⁷Cs concentration level in soil and rock samples is found to be 15.04 ± 0.29 and 5.7 ± 0.16 Bq kg^?1, respectively. The average radium equivalent activity (R _aeq) was found as 143.16 and 142.93 Bq kg^?1 in soil and rock samples, respectively. These findings are less than the recommended safe value of 370 Bq kg^?1 as given in OECD report (1979). The values of external (H _ex) and internal hazard index (H _in) are also less than unity. Mean value of absorbed dose rate was found as 69.78 nGy h^?1 for the soil samples, which is in good agreement with the world wide average value (70 nGy h^?1). Mean value of absorbed dose rate from rock samples was found as 70.01 nGy h^?1. Mean values of the annual effective dose is also lower than the values reported for different other countries of the world.     

Natural radioactivity and their radiological effects for different types of rocks from Egypt

The present work investigated the radioactivity level of the rocks samples collected from different sites in Egypt. Twenty one rocks samples were analyzed by gamma-ray spectrometry using NaI(Tl) detector with specially designed shield. The concentration of three natural radionuclides namely ²²⁶Ra, ²³²Th and ⁴⁰K has been determined and compared with chemical data obtained by XRF analysis. The results showed that these radionuclides were present in concentration ranges (3.4-99, 7.5-134 and 93-3382 Bq kg⁻¹), (54.9-211.6, 20.71-170.5 and 2068-2344 Bq kg⁻¹) and (13-106, 29.25-106.1 and 682-755 Bq kg⁻¹) for gneiss, granite and basalt rocks, respectively, while the values were (7.5, 12.5 and 263.9 Bq kg⁻¹) and (113, 148.5 and 1672 Bq kg⁻¹) for ²²⁶Ra, ²³²Th and ⁴⁰K in sandstone and siltstone rocks, respectively. Also radium equivalent activity, total dose rates and external hazard index of the rocks samples under consideration were calculated. The results showed that granite rocks contain a high proportion of natural radioactive elements, while sandstone rocks have lesser radioactivity concentration compared with other types of rocks.     

Measurement of activity concentration of primordial radionuclides in soil samples from Thirthahalli taluk and the assessment of resulting radiation dose

The activity concentration of primordial radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K in soil samples of Thirthahalli taluk were measured systematically by using a low background HPGe detector coupled to 16 K MCA. The measured activity concentration of ²²⁶Ra lies between 5.1?±?0.2 and 79.5?±?1.7 Bq kg^?1with an average activity of 25.99 Bq kg^?1, ²³²Th ranges from 5.1?±?0.3 to 95.3?±?2.2 Bq kg^?1with an average activity of 33.60 Bq kg^?1and that of ⁴⁰K varies from 18.3?±?1.5 to 833.4?±?17.5 Bq kg^?1with an average activity of 175.52 Bq kg^?1. Higher concentration of these radionuclides were found in the soil samples where the regional geology is granites. The consequential gamma dose and the corresponding radiation hazard was also estimated and is found to be within the permissible limits. The possible radiological impact on the public was also determined and these results are presented in this paper.     

Effect of the natural radioactivity concentrations and 226Ra/238U disequilibrium on cancer diseases in Penang,Malaysia

Natural radioactivity measurements and assessment of radiological hazards in soil and sand samples obtained from Penang, Malaysia were carried out using the Exploranium GR-135 Plus “Identifier” Radioisotope Identification Device and high-resolution High Purity Germanium (HPGe) detector system. The activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 184±11, 396±22, 165±14, and 835±28 Bq kg^?1 respectively, and the external gamma dose rate is 315±44 nGy h^?1 for soil samples. For sand samples, the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 31±8, 62±16, 36±6, and 369±17 Bq kg^?1, respectively, and the external gamma dose rate is 66±12 nGy h^?1. To assess the radiological hazard of radioactivity present in the samples, the radium equivalent activity, annual effective dose, annual gonadal dose equivalent, external hazard, and internal indices were calculated.The Ra_eq values of soil samples were higher than the limit of 370 Bq kg^?1, which is equivalent to a gamma dose of 1.5 mSv yr^?1, whereas the Ra_eq for sand samples was lower than 370 Bq kg^?1. The calculated concentrations by HPGe spectroscopy were compared with the measured concentrations detected by a GR-135 spectrometer. The calculated and measured gamma dose rates had an ideal correlation coefficient R of 0.72. The gamma dose rates in Penang increased with the average annual age-standardized rates (ASR) for all cancers between 1994 and 2010. The effects of the pH value of soil and sand samples on natural radionuclides concentrations were investigated. The high concentration of ²²⁶Ra/²³⁸U ratio disequilibrium (²²⁶Ra/²³⁸U of 1.76–2.33) was observed in the sampling sites. Moreover, a portable continuous radon monitor (SNC, model 1029, Sun Nuclear Corporation) was used to measure the radon concentration of the soil surface. The radon concentrations were found to vary from 7 to 50 Bq m^?3. A positive correlation was observed between the radon and radium concentrations in samples measured by the SNC continuous radon monitor and HPGe detector.     

Measurement of the radioactivity of 238U, 226Ra, 210Pb, 228Th, 232Th, 228Ra, 137Cs and 40K in tea using gamma-spectrometry

The aim of the present work was to determine the concentration of radionuclides in all kinds of tea available at the local Egyptian market. Radioactivity of the nuclides ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²²⁸Th, ²³²Th, ²²⁶Ra, ¹³⁷Cs and ⁴⁰K were measured in tea by direct γ-ray spectrometry using HPGe detector and their mean values were 16.0±5.3, 3.1±0.7, 34.3±3.4, 3.4±1.2, 3.0±0.6, 3.1±0.8, 0.9±0.2 and 623±25 Bq·kg⁻¹, respectively.     

Statistical assessment of radiological data of tiles collected from Jordan

ABSTRACT

In this present study, activity concentration of natural radionuclides such as ²²⁶Ra, ²³²Th and ⁴⁰K were determined using gamma ray spectrometer based on High Purity Germanium (HPGe) detector in ceramic tiles collected from Jordan. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 63.75 ± 24.12, 93.65 ± 13.89 and 180.9 ± 45.69 Bq.kg^?1. respectively. Using activity concentration of ²²⁶R, ²³²Th and ⁴⁰K, the radiological parameters such as radium equivalent activity (Ra_eq), Criteria formula (CF), absorbed dose rate (D_R), annual effective dose rate (H_R), activity utilisation index (AUI), external hazard index (H_ex), international hazard index (H_in), alpha index and gamma index (I_γ) has been calculated to assess the radiation hazards in the Tiles. The calculated average value of all radiological parameters is less than the recommended limit. The calculated values of annual effective dose rate (H_R), show that about 30% of the samples exceeded the recommended limit of 1 mSv.y^?1. Moreover, multivariate statistical techniques such as Pearson correlation, factor and cluster analysis were performed between the radioactive variables to know the existing relation between them.     

Activity concentrations of 226Ra, 228Ra, 222Rn and their health impact in the groundwater of Jordan

The activity concentrations of ²²⁶Ra, ²²⁸Ra and ²²²Rn were measured in 87 groundwater samples to estimate the activity concentrations of these radionuclides and health impact due to intake of these radionuclides in groundwater of Jordan. The mean activity concentrations of ²²⁶Ra, ²²⁸Ra and ²²²Rn in groundwater were found to be 0.293?±?0.005 Bq L^?1, 0.508?±?0.009 Bq L^?1 and 58.829?±?8.824 Bq L^?1, respectively. They give a mean annual effective dose of 0.481 mSv with mean lifetime risk of 24.599?×?10^?4, exceeding the admissible limit of 10^?4. Most of the received annual effective dose (59.15% of the total) is attributed to ²²⁸Ra.

     

Assessment of natural radioactivity in silt samples from Moticher lake near Kakrapar Atomic Power Station,India

The naturally occurring radioisotopes such as ²³⁸U, ²³²Th and ⁴⁰K in the silt samples collected from Moticher lake, Gujarat were evaluated. The activity of ²³⁸U, ²³²Th and ⁴⁰K was found to be 4.4-9.7 Bq kg⁻¹ with a mean 6.4 ± 1.3 Bq kg⁻¹, 10.5–21.2 Bq kg⁻¹ with a mean 15.6 ± 2.5 Bq kg⁻¹ and 102–231 Bq kg⁻¹ with a mean 160 ± 40 Bq kg⁻¹, respectively. The depth profile study could not reveal any significant vertical correlation on radioactivity levels of ²³⁸U, ²³²Th and ⁴⁰K. Radium equivalent activity (Ra_eq), external hazard index (H _ex) and internal hazard index (H _int) were calculated by using the activity of ²³⁸U or ²²⁶Ra, ²³²Th and ⁴⁰K in silt samples. Annual Effective Dose Equivalent (AEDE) level in Moticher silt was found to be 24.8 ± 5.0 μSv year⁻¹, which is much lower than the worldwide average value. The relative contribution to dose due to ²³⁸U and ²³²Th series were found to be 14% and 53%, followed by the contribution of 33% due to ⁴⁰K.     

Preparation and application of alginate-Ca/attapulgite clay core/shell particle for the removal of uranium from aqueous solution

The radioactivity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in 42 samples from different types of cements produced in Turkey were measured using gamma-ray spectrometer. The determined values were 18–143 Bq kg⁻¹ (²²⁶Ra), 5–66 Bq kg⁻¹ (²³²Th) and 142–540 Bq kg⁻¹ (⁴⁰K). Additionally, the calculated radiological hazard parameters such as absorbed dose rate, annual effective dose, radium equivalent activity, the external hazard, activity and alpha indices were found to be in the range of 38–158 nGy h⁻¹, 188–776 µSv year⁻¹, 41–182 Bq kg⁻¹, 0.11–0.49, 0.15–0.65 and 0.09–0.71, respectively. Finally, the results were statistically evaluated and compared with the reported data in other countries and the international standard values given by European Commission and UNSCEAR.

     

The role of phosphate released from Na–Al–P glass under repository conditions in speciation and transport of americium

The uptake of natural radioactivity by pasture-grass collected from seven different grasslands of Digor was calculated. The activities of ²²⁶Ra, ²³²Th and ⁴⁰K in pasture-grass were in the range of 21.8 ± 6.3–49.6 ± 13.4, 51.9 ± 13.2–127.7 ± 23.8 and 309.5 ± 33.5–807.3 ± 64.4 Bq kg⁻¹, respectively. The soil to pasture-grass transfer factors were evaluated and determined to be in the range from 0.26 ± 0.13 to 0.69 ± 0.34, 0.64 ± 0.27 to 1.99 ± 0.40 and 0.64 ± 0.014 to 1.40 ± 0.032 for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The distribution of ²²⁶Ra and ²³²Th in different parts of pasture-grass indicated a decreasing tendency in order of root > stem > leaf. ⁴⁰K mainly accumulated in stem of pasture-grass and is followed by declining trend stem > leaf > root.

     

Radioactivity measurements and radiation dose assessments due to natural radiation in Karabük (Turkey)

In this work, the radionuclide activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in surface soils and radon levels in dwellings of Karabük, Turkey were determined in order to evaluate the environmental radioactivity. Concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides were determined using gamma spectrometry with using HPGe detector. The etch track detectors (CR-39) were used to determine the distribution of radon concentrations. The average activity concentrations for ²²⁶Ra, ²³²Th and ⁴⁰K were found as 21.0, 23.5 and 363.5 Bq kg⁻¹, respectively. The calculated average annual effective dose equivalent from the outdoor terrestrial gamma radiation from ²²⁶Ra, ²³²Th and ⁴⁰K is 53.5 μSv y⁻¹. The average radon concentration and annual effective dose equivalent of ²²²Rn in Karabük dwellings were obtained 131.6 Bqm⁻³ and 3.32 mSv y⁻¹, respectively. The evaluated data were compared with the data obtained from different countries.