Average Activity Concentrations Of 232Th Research Articles

Activity concentrations and radiological hazard assessments of 226Ra, 232Th, 40K, and 137Cs in soil samples obtained from the Dongnam Institute of Radiological & Medical Science, Korea

The radioactivity concentration of environmental radionuclides was analyzed for soil and sand at eight locations within a radius of 255 m centered on the Dongnam Institute of Radiological & Medical Science (DIRAMS), Korea. The average activity concentrations of 40K, 137Cs, 226Ra, and 232Th were 661.1 Bq/kg-dry, 0.9 Bq/kg-dry, 21.9 Bq/kg-dry, and 11.1 Bq/kg-dry, respectively. The activity of 40K and 137Cs was lower than the 3-year (2017–2019) average reported by the Korea Institute of Nuclear Safety, respectively. Due to the nature of granite-rich soil, the radioactivity of 40K was 0.6-fold higher than in other countries, while 137Cs was in the normal fluctuation range (15–30 Bq/kg-dry) of the concentration of radioactive fallout from nuclear tests. The activity of 226Ra and 232Th was lower than in Korean soils reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average activity concentrations of 232Th and 40K for the soil and sand samples from DIRAMS were within the range specified by UNSCEAR in 2000. The radium equivalent activity and internal and external hazard index values were below the recommended limits (1 mSv/y). These radionuclide concentration (226Ra, 232Th, 40K, and 137Cs) data can be used for regional environmental monitoring and ecological impact assessments of nuclear power plant accidents.

Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh.

This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg-1, 19.69 ± 2.15 Bqkg-1, and 347.82 ± 24.50 Bqkg-1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.

Investigating NORMs transfer factor in food items harvested from Gerado agricultural soil, and their related health hazards Dessie, Ethiopia

ABSTRACT In this study, the activity concentration of NORMs were measured using gamma spectrometer, based on NaI(Tl) detector with Maestro-32 installed computer soft- ware. Accordingly, the average activity concentrations of 232Th, 238U, and 40K in soil samples were found 17.85±0.50, 40.16±0.54, and 271.46±0.07, respectively, which are lower than the average world recommended values given by UNSCEAR 2000 for Th and K, but higher for U decay series. In the same way, activity concentration of NORMs in food items cultivated from the irrigation site were measured and the highest activity concentrations were observed in bean samples. The transfer factors of 232Th, 238U and 40K from soil to food items were computed based on the measured activity values, and in most food items it is observed above the world average values. The consecutive chronic daily intake via ingestion for some food items from samples are also above the permissible limit. The transfer factor from Gerado agricultural soil to plant exceed the world average values in the cases of 232Th and 238U according to our study.

The influence of sedimentation regime on natural radionuclide activity concentration in marine sediments of the East Siberian Arctic Shelf

Transport and accumulation of radionuclides in the Arctic depends on many biogeochemical processes, which are changing at accelerated rates due to climate change and human economic activity. We present the results of a study on the features distribution of some natural radionuclides in the marine sediments on the East Siberian Arctic Shelf collected during several expeditions from 2008 to 2019. Average activity concentration of 232Th, 40K and 226Ra under the influence of different sedimentation regime increases from 40.7, 418 and 30.8 Bq/kg to 41.6, 423 and 34.9 Bq/kg respectively from coastal shelf marine sediments (<50% clay) to outer shelf marine sediments (>50% clay). Sediment particle size has a greater impact on radionuclides in the coastal shelf. An increase in the activity concentrations of 232Th and 226Ra with the increasing clay particles were found. On the outer shelf with a change in the sedimentation regime, the influence of the size composition decreased, at the same time, there is a correlation between the organic carbon concentration and the radionuclide activity concentration. Absolute maximums of natural radionuclide activity concentration (232Th = 70.9, 226Ra = 70.4, 40K = 591 Bq/kg) were detected in the Chaun Bay. The highest activity concentration of 226Ra was found in paleo-river valleys marine sediments. A low 232Th/226Ra activity concentration ratio indicates the enrichment of paleo-river valleys marine sediments with 226Ra. In the deep-sea sediments of the shelf slope on the contrary paleo-river valleys, this ratio is greatly increased.

Radiological hazard levels of construction rocks excavated from quarries in Kericho county, Kenya

The study determined the natural activity concentration levels of 40K, 232Th and 238U in rocks used for construction from the 15 selected quarries in Kericho County, Kenya through Gamma-ray Spectrometric analysis at the Physical Sciences department of South Eastern Kenya University (SEKU). IAEA procedures were followed from sample collection, preparation and measurement. Samples were collected, crushed, oven dried at 105 , weighed and packed in sealed containers and kept for four weeks in order for secular equilibrium to be achieved between 226Ra and 232Th. The average activity concentration of 232Th, 238U and 40K were 101 ± 5 Bq/kg, 56 ± 3 Bq/kg and 1100 ± 55 Bq/kg and ranged from 41 ± 2 to 138 ± 7 Bq/kg, 26 ± 1 to 116 ± 6 Bq/kg and 512 ± 26 to 1919 Bq/kg ± 96 Bq/kg respectively. The average external and internal hazard indices were 0.8 mSv/y and 0.9 mSv/y respectively. Radium equivalent ranged from 222 ± 11 Bq/kg to 366 ± 18 Bq/kg with an average value of 285 ± 14 Bq/kg which was below the permissible limit of 370 Bq/kg; therefore, the excavated rocks for construction from the selected quarries in Kericho county poses insignificant health risk to the general population and quarry workers.

Assessment of Radioactivity and Radiological Hazard of Different Food Items Collected from Local Market in Bangladesh

Sixteen samples in three categories vegetables, cereals (rice, wheat, maize, pulse) and powdered milk were collected from local markets (Dhaka city) in Bangladesh and analyzed by using High Purity Germanium (HPGe) Detector for the assessment of natural and artificial radioactivity. In vegetables (potato, raw banana, giant taro, red amaranth), the average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.82±11.57, 54.93±9.98 and 617.43±65.69 Bqkg-1 respectively, for cereals (rice, wheat, maize, pulse) 24.01±3.67, 31.46±4.00 and 474.83±27.68 Bqkg-1 respectively and for milk samples 15.01±3.65, 26.73±6.77 and 494.21±38.71 Bqkg-1 respectively. The average values of outdoor annual effective dose were found to be 92.18, 61.19 and 52.37μSvy-1 in vegetables, cereals and milk samples respectively. No artificial radionuclide was found in any of these samples. The average value of radium equivalent activity in all samples was 113.89 Bqkg-1 which was less than maximum permissible value 370 Bqkg-1. The values of external hazard indices for vegetables, cereals and milk samples varied from 0.31 to 0.66, 0.17 to 0.40 and 0.11 to 0.36 respectively which is less than unity in all samples that indicate the non-hazardous nature of the samples. The average values of annual effective ingestion dose rate from foods (for adult) were 274.33 μSvy-1, 533.60μSvy-1, and 132.73μSvy-1for 232Th, 226Ra and 40K respectively. These data would be useful to establish a baseline for natural radioactivity concentrations in food items consumed in Bangladesh.&#x0D; Journal of Bangladesh Academy of Sciences, Vol. 43, No. 2, 141-148, 2019

Assessment of gamma radiation and associated radiation hazards in coastal sediments of south east coast of Tamilnadu, India with statistical approach

Gamma spectroscopy was performed to determine the concentrations of 226Ra, 232Th and 40K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg−1 for 226Ra, 85.67 Bq kg−1 for 232Th and 425.72 Bq kg−1 for 40K. The average activity concentration of 232Th and 40K are slightly higher and 226Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Raeq) Absorbed Gamma Dose Rate (DR), Annual Effective Dose Rate (HR), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE), Internal Hazard Index (Hin) and External Hazard index (Hex) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides.

Determination of radioactivity levels and associated hazards of coastal sediment from south east coast of Tamil Nadu with statistical approach

The concentration of 238U, 232Th and 40K in sediment samples collected from Thazhankudato Kodiyakkarai along the east coast of Tamil Nadu, India was measured using γ-spectrometry. Measured mean activity concentrations are 3.3, 40.45 and 389.28 Bq kg−1 for 238U, 232Th and 40K, respectively. The average activity concentration of 232Th is slightly higher than the world average value. The radiation hazards such as radium equivalent activity, absorbed gamma dose rates in air, the annual gonadal dose equivalent, annual effective dose equivalent, external hazard index, internal hazard index, representative level index and excess lifetime cancer risk associated with the radionuclides were calculated. Heat production rate of sediments and spatial distribution of radionuclides is studied. The multivariate statistical analysis, such as Pearson correlation, principal component and cluster analysis were applied to know the existing relation between radiological variables. From the analysis, the radioactivity levels in sediment samples do not pose any environmental health problem. Thus, the presented data provide a general background of the detectable radionuclides for the study area and can be helpful in future epidemiological studies.

Radionuclides content in grape molasses soil samples from Central Black Sea region of Turkey

ABSTRACTThe activity concentrations of radionuclides in grape molasses soil samples collected from Zile (Tokat) plain in the Central Black Sea region of Turkey were measured by using gamma spectrometer with a NaI(Tl) detector. Also, the concentrations of 222Rn in soil samples and air were estimated essentially taking the activity concentrations of 226Ra measured in soil samples. Grape molasses soil samples with calcium carbonate content are used for sedimentation for making molasses in this region. The average activity concentrations of 232Th, 226Ra, 40K, and 137Cs were found as 62 ± 2, 68 ± 3, 479 ± 35, and 8.0 ± 0.3 Bq kg−1, respectively. The average concentrations of 222Rn in soil samples and air were estimated to be 50 kBq m−3 and 144 Bq m−3. From the activity concentrations, absorbed gamma dose rate in outdoor air (D), annual effective dose from external exposure (EE), annual effective dose from inhalation of radon (EI), and excess lifetime cancer risk (ELCR) were estimated in order to assess radiological risks. The average values of D, EE, EI, and ELCR were found to be 90 nGy h−1, 110 μSv y−1, 1360 μSv y−1, and 4 × 10−4, respectively.

Natural radioactivity in soil samples of Yelagiri Hills, Tamil Nadu, India and the associated radiation hazards

The natural radioactivity of soils at Yelagiri hills has been studied in this paper. The radioactivities of 25 samples have been measured with a NaI(Tl) detector. The radioactivity concentrations of 238U, 232Th and 40K ranged from ≤2.17 to 53.23, 13.54 to 89.89 and from 625.09 to 2207.3Bqkg−1, respectively. The measured activity concentrations for these radionuclides were compared with world average activity of soil. The average activity concentration of 232Th in the present study is 1.19 times higher than world median value while the activity of 238U and 40K is found to be lower. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity Raeq, the absorbed dose rate DR, the annual effective dose rate and the external hazard index (Hex) have been calculated and compared with the internationally approved values. The study provides background radioactivity concentrations in Yelagiri hills.

Measurement of naturally occurring radioactive materials (NORM) in beach sand minerals using HPGe based gamma-ray spectrometry

This paper discusses the measurement of naturally occurring radioactivity materials (NORM) in beach sand minerals using high resolution gamma spectrometry. In India, the beach sand minerals of economic interest from coastal Kerala, Tamil Nadu and Orissa are enriched with NORM due to the occurrence of monazite deposits and heavy minerals such as zircon, ilmenite, magnetite, garnet, rutile etc. Since many of these ores are rich in 232Th and other radio elements, certification of radioactivity levels has become mandatory in recent years. The average activity concentrations of 226Ra in zircon, rutile and garnet were 3,531, 1,134 and 17 Bq kg−1, respectively. The average activity concentration of 232Th observed in zircon, rutile and garnet were 618, 454 and 64 Bq kg−1, respectively. Concentration of 226Ra, 232Th, and 40K in ilmenite ore ranged from 17.6–444 Bq kg−1, 80.4–1971 Bq kg−1 and ≤5.5–25.0 Bq kg−1, respectively.

Radioactivity concentrations in topsoil samples from the Thrace region of Turkey and assessment of radiological hazard

The activity concentrations of gamma emitting radionuclides were measured in surface soil samples from the Thrace region. 232Th, 238U, 226Ra, 40K and 137Cs activities and physico-chemical parameters of the soil samples were determined in samples collected from 73 sampling stations. Radionuclide concentrations measured were compared with those found in the samples from other locations of Turkey and from different countries. The average activity concentrations of 232Th, 238U, 226Ra, 40K and 137Cs were found to be 24.71 ± 8.79, 22.30 ± 7.93, 32.09±12.44, 509.00±160.05, 32.74±29.24 Bq kg−1, respectively. The mean value of the annual effective dose equivalent from the outdoor terrestrial gamma radiation was calculated as 57.2 μ Sv.

Radioactivity levels in soil of salt field area, Kelambakkam, Tamilnadu, India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer. The activity concentration for 232Th, 238U and 40K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg, and from 135.54 to 381.28 Bq/kg, respectively. The measured activity concentrations for these radionuclides were compared with world average activity of soil. The average activity concentration of 232Th in the present study is 1.19 times higher than world median value while the activity of 238U and 40K is found to be lower. The absorbed dose rates due to these radionuclides were calculated. The average absorbed gamma dose rate due to the presence of 232Th, 238U and 40K in soil samples is 36.99 nGy·h -1. These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.

Background radiation study in Coimbatore city, Tamilnadu

The activity concentration and absorbed gamma dose rates due to primordial radionuclides (238U, 232Th and 40K) have been determined for the soil of Coimbatore city using NaI(Tl) gamma-ray spectrometer. The average activity concentrations of 232Th, 238U and 40K in the soil samples have been found to be 31.4 Bq·kg−1, 12.8 Bq·kg−1 and 698.0 Bq·kg−1, respectively, which give the total gamma dose rate contribution of 56.4 nGy·h−1. Grab sampling technique has been used to determine the indoor radon (222Rn) and thoron (220Rn) progeny levels in different dwellings in the city. The concentrations of radon and thoron progenies range from 0.4 to 10.4 and from 0.7 to 12.7 mWL with a mean value of 1.4 mWL and 3.1 mWL, respectively. The annual effective dose due to radon and thoron progeny has been found to be 0.14 mSv·y−1.