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Sample records for 226ra 232th 40k

  1. The Concentrations of {sup 40}K, {sup 226}Ra and {sup 232}Th in Soil Sample in Osmaniye (Turkey)

    SciTech Connect

    Akkurt, I.; Guenoglu, K.; Kara, A.; Mavi, B.; Karaboerklue, S.

    2011-12-26

    The {sup 40}K, {sup 226}Ra and {sup 232}Th concentration is due to the magmatic structure of the earth and it can be varied from place to place. Osmaniye is located in the Eastern side of Mediteranean Region. It holds the climatic characteristics of the same region and arises with Middle Taurus Mountains from west to North and with Amonos Mounations in East and West-east parts and is situated between 35 deg. .52'-36 deg. .42' east longitudes and 36 deg. .57'-37 deg. .45' north latitudes. In this study, the natural radioactivity concentrations {sup 40}K, {sup 226}Ra and {sup 232}Th in some soil samples collected in Osmaniye have been investigated. The measurements have been performed using 3x3{sup ''} NaI(Tl) detector system.

  2. (226)Ra, (232)Th and (40)K contents in soil samples from Garhwal Himalaya, India, and its radiological implications.

    PubMed

    Ramola, R C; Gusain, G S; Badoni, Manjari; Prasad, Yogesh; Prasad, Ganesh; Ramachandran, T V

    2008-09-01

    The exposure of human beings to ionising radiation from natural sources is a continuing and inescapable feature of life on earth. Natural radionuclides are widely distributed in various geological formations and ecosystems such as rocks, soil groundwater and foodstuffs. In the present study, the distribution of (226)Ra, (232)Th and (40)K was measured in soil samples collected from different lithological units of the Thauldhar and Budhakedar regions of Garhwal Himalaya, India. The collected soil samples were analysed using gamma ray spectrometry. The activity concentrations of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K in these soil samples were found to vary from below detection level (BDL) to 131 +/- 18 Bq kg(-1), 9 +/- 6 to 384 +/- 53 Bq kg(-1) and 471 +/- 96 to 1406 +/- 175 Bq kg(-1), respectively. The distribution of radionuclides depends upon the rock formation and chemical properties within the earth. The activity concentrations vary widely depending on the sample origin. The external absorbed gamma dose rates due to (226)Ra, (232)Th and (40)K were found to vary from 49 to 306 nGy h(-1). The average radium equivalent activity from these soil samples was 300 Bq kg(-1). PMID:18714132

  3. Soil-to-root vegetable transfer factors for (226)Ra, (232)Th, (40)K, and (88)Y in Malaysia.

    PubMed

    Asaduzzaman, Kh; Khandaker, Mayeen Uddin; Amin, Y M; Bradley, D A; Mahat, R H; Nor, R M

    2014-09-01

    Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides (226)Ra, (232)Th, (40)K, and for the anthropogenic radionuclide (88)Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide (88)Y, although the uptake of (88)Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for (226)Ra and (232)Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y(-1)). PMID:24814722

  4. Natural radioactivity (226Ra, 232Th and 40K) and assessment of radiological hazards in the Kestanbol granitoid, Turkey.

    PubMed

    Canbaz, Buket; Cam, N Füsun; Yaprak, Günseli; Candan, Osman

    2010-09-01

    The surveys of natural gamma-emitting radionuclides in rocks and soils from the Ezine plutonic area were conducted during 2007. Direct dose measurement using a survey meter was carried out simultaneously. The present study, which is part of the survey, analysed the activity concentrations of (238)U, (232)Th and (40)K in granitoid samples from all over the region by HPGe gamma spectrometry. The activity concentrations of (226)Ra ranged from 94 to 637 Bq kg(-1), those of (232)Th ranged from 120 to 601 Bq kg(-1)and those of (40)K ranged from 1074 to 1527 Bq kg(-1) in the analysed rock samples from different parts of the pluton. To evaluate the radiological hazard of the natural radioactivity in the samples, the absorbed dose rate (D), the annual effective dose rate, the radium equivalent activity (Ra(eq)) and the external (H(ex)) hazard index were calculated according to the UNSCEAR 2000 report. The thorium-to-uranium concentration ratios were also estimated. PMID:20529959

  5. Measurement of 226Ra, 232Th, 137Cs and 40K activities of Wheat and Corn Products in Ilam Province – Iran and Resultant Annual Ingestion Radiation Dose

    PubMed Central

    CHANGIZI, Vahid; SHAFIEI, Elham; ZAREH, Mohammad Reza

    2013-01-01

    Background: Background: Natural background radiation is the main source of human exposure to radioactive material. Soils naturally have radioactive mineral contents. The aim of this study is to determine natural (238 U, 232 Th, 40 K) and artificial (137 Cs) radioactivity levels in wheat and corn fields of Eilam province. Methods: HPGe detector was used to measure the concentration activity of 238 U and 232 Th series, 40 K and 137 Cs in wheat and corn samples taken from different regions of Eilam province, in Iran. Results: In wheat and corn samples, the average activity concentrations of 226 Ra, 232 Th, 40 K and 137 Cs were found to be 1, 67, 0.5, 91.73, 0.01 and 0.81, 0.85, 101.52, 0.07 Bq/kg (dry weight), respectively. H ex and H in in the present work are lower than 1. The average value of H ex was found to be 0.02 and 0.025 and average value of H in to be found 0.025 and 0.027 in wheat fields samples and corn samples in Eilam provinces, respectively. The obtained values of AGDE are 30.49 mSv/yr for wheat filed samples and 37.89 mSv/yr for corn samples; the AEDE rate values are 5.28 mSv/yr in wheat filed samples and this average value was found to be 6.13 mSv/yr in corn samples in Eilam. Transfer factors (TFs) of long lived radionuclide such as 137 Cs, 226 Ra, 232 Th and 40 K from soils to corn and wheat plants have been studied by radiotracer experiments. Conclusion: The natural radioactivity levels in Eilam province are not at the range of high risk of morbidity and are under international standards. PMID:26056646

  6. Estimation of dose contribution from 226Ra, 232Th and 40K radon exhalation rates in soil samples from Shivalik foot hills in India.

    PubMed

    Chauhan, R P; Chauhan, Pooja; Pundir, Anil; Kamboj, Sunil; Bansal, Vakul; Saini, R S

    2014-01-01

    The concentration of radium, thorium and potassium and radon exhalation rates in soil samples collected from Shivalik foot hills in the states of Haryana and Himachal Pradesh (India) were experimentally measured. A high-resolution gamma-ray spectroscopic system was used for the measurement of natural radioactivity ((226)Ra, (232)Th and (40)K) at Inter-University Accelerator Center, New Delhi, using a coaxial n-type high-purity germanium detector (EG&G, ORTEC, Oak Ridge, USA). The mass exhalation rates (EM) of radon in soil samples from the study area measured by 'sealed canister technique' using LR-115 type II track detectors varied from 50±1 to 143±6 mBqkg(-1) h(-1). The activity concentrations of (226)Ra, (232)Th and (40)K in various soil samples of the study area varied from 31±1.3 to 63±4.6, 53±1.8 to 78±2.6 and 472±4.8 to 630±7.0 Bq kg(-1) respectively. The results indicated some higher levels of radioactivity in Lal Dhang peak area of the hills compared with other locations under study. PMID:23893776

  7. Vertical Profiles Of {sup 226}Ra, {sup 232}Th And {sup 40}K Activities In Rocks From The Irati Formation Of The Parana Sedimentary Basin, Southern Brazil

    SciTech Connect

    Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution {gamma}-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Parana sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 1.84 Bq{center_dot}kg{sup -1} for {sup 232}Th and 4.20 Bq{center_dot}kg{sup -1} for {sup 40}K. Activity concentrations were determined for {sup 226}Ra (from 16.22 to 151.55 Bq{center_dot}kg{sup -1}), {sup 232}Th (from 2.93 to 56.12 Bq{center_dot}kg{sup -1}) and {sup 40}K (from 38.45 to 644.63 Bq{center_dot}kg{sup -1}). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81{+-}0.22 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 4.21{+-}0.07 Bq{center_dot}kg{sup -1} for {sup 232}Th, and 50

  8. Vertical distributions of 137Cs, 40K, 232Th and 226Ra in soil samples from Istanbul and its environs, Turkey.

    PubMed

    Belivermiş, Murat

    2012-09-01

    Determining the distribution of natural and artificial radionuclides in soil profiles as well as the surface layer of the soil is necessary due to the fact that radionuclides can enter the food chain from deeper soil layers and also contaminate ground water. In the current study, the activity-depth profiles of (137)Cs were determined in soil samples from 20 sites in and around the city of Istanbul. Naturally  occurring radionuclides were determined at 12 of the locations. Uncultivated soil samples were taken in six horizontal layers at each location. Activity concentrations were measured with a gamma spectrometer. The impacts of texture, organic matter and pH of the soil on the vertical distribution of the radionuclides were also studied. The average and standard deviations of (137)Cs and (40)K activity concentrations in soil at a depth of 5 cm were found to be 16.46±14.71 and 450.2±239.1 Bq kg(-1), respectively. The activity concentrations of (40)K, (232)Th and (226)Ra were distributed uniformly with regard to soil depth. The depth distribution of (137)Cs generally fitted a linear function. The study revealed that >20 y after the Chernobyl disaster of 1986, 55 % of (137)Cs still remains in the upper 10 cm of soil in the Istanbul environment. PMID:22408185

  9. [Uptake of radionuclides from soil to plant and the discovery of 226Ra, 232Th hyperaccumulator].

    PubMed

    Zhang, Zhi-Qiang; Chen, Di-Yun; Song, Gang; Yue, Yu-Mei

    2011-04-01

    11 sorts of plant samples and corresponding soil samples were collected in Conghua and Taishan, Pearl River Delta. The specific activity of 238U, 226Ra, 232Th and 40K of samples were investigated by using HPGe-gamma-ray spectra analysis. The results showed that the average specific activity of 238U, 226Ra, 232Th and 40K in soil samples were 151.8, 146.3, 226.6, 665.5 Bq/kg, which were higher than the average values of China and the world. The concentration of 238U in all sort of plants are very low and most of them are lower than detection limit, while the values of 226Ra, 232Th and 40K were high. The contents of 226Ra and 232Th in Dicranopteris dichotoma were the highest, whose average specific activity is 285.9, 986.2 Bq/kg respectively. The average bioconcentration factors (BFs)of 26Ra, 232Th of Dicranopteris dichotoma were 2.20, 4.23, respectively, the other 10 sort of plants have BFs of 2266Ra, 232Th were in the range of 10(-1)-10(-2). The bioconcentration factors and the translocation factors of 226Ra, 232Th of Dicranopteris dichotoma. were all bigger than 1, so Dicranopteris dichotoma can be defined as hyperaccumulator of 226Ra and 232Th. PMID:21717763

  10. Activity concentrations of 226Ra, 232Th, 40K and 137Cs radionuclides in Turkish medicinal herbs, their ingestion doses and cancer risks

    NASA Astrophysics Data System (ADS)

    Parmaksız, Aydın; Ağuş, Yusuf

    2014-11-01

    Twenty-two medicinal herb samples, each representing a distinct species, were collected from Turkish markets and measured by the gamma spectrometric method. The activity concentration of 226Ra in medicinal herbs was found in the range of minimum detectable activity (MDA) and 15.1 ± 2.2 Bqkg-1. The activity concentration of 232Th ranged from MDA values to 3.5 ± 0.8 Bqkg-1. The activity concentration of 40K varied between 50.0 ± 16.8 and 1311.5 ± 57.3 Bqkg-1. All 137Cs activity concentrations of medicinal herbs were found to have lower than MDA values. The bone surface dose, lower large intestine and colon doses were found to be 182.9, 18.8 and 18.7 µSvy-1, respectively. The highest committed effective dose originated from the annual ingestion of 1 kg medicinal herb was calculated notably low as 9.0 µSv. The cancer risk of ingestion of medicinal herbs was found to be small enough to be neglected. The selected Turkish medicinal herbs are considered safe for human consumption.

  11. Modern Formation of Isotope System ( 40k, 137 Cs 226ra, 232th) In Exogenous Conditions Water Catch Basin of The White Sea

    NASA Astrophysics Data System (ADS)

    Yudakhin, F. N.; Kiseljov, G. P.; Bazhenov, A. V.

    Water modular basin of the White sea occupies a number of geological provinces. Northern and western parts are combined archey-paleozoic complex of metamorphogenic and magmatogenic mountain rock, which is blocked sporadically by low-power tundra and taiga soils. Southern, southeast and east is combined by sedimentary Paleozoic complex ? ?zen sinecliza, partially blocked by sea deposits of last freezing, on which the tundra's, southern tundra, northern and middle taiga settle down of ground actually. The ground deposits in rivers, lakes and White sea are formed from the all variety of mountain rocks, composing the territory, and up soil horizon. We investigated a system of isotopes (40K, 137Cs226Ra, 232Th,) in soils, bottom deposits of rivers, lakes and White sea, on more than 1500 tests, that allows to consider the modern spatial formation of isotope systems in soils and bottom deposits of the region. Findings about concentration of isotopes in genetic horizons of soils show the change of isotope sy stem depending on climatic zones and reflect an isotope status of environment, which basically delivers a material for bottom deposits of rivers and White sea. For bottom deposits of rivers characteristic is the following - from the washed out sand is occurs carrying out of all radionuclides, in silt sand and ooze there is an accumulation radionuclides, including 137Cs. That the silt deposits in the rivers water catch basin of the White sea occupy the subordinated situation among bottom deposits, radionucli des are actively taken out in White sea, where they collect. As a result of modern soil destruction (natural and technogenic influence) and sediment accumulation in water basin, there is a modern migration of radioactive isotopes in horizontal and vertical directions, therefore the new isotope systems are formed. Thus in soil horizons they are not steady and change at change of a climate and biological system, and in bottom deposits they are steady and further pass

  12. Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

    PubMed

    Zare, Mohammad Reza; Kamali, Mahdi; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland. PMID:26490904

  13. Ingestion dose from 238U, 232Th, 226Ra, 40K and 137Cs in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha, India.

    PubMed

    Lenka, Pradyumna; Sahoo, S K; Mohapatra, S; Patra, A C; Dubey, J S; Vidyasagar, D; Tripathi, R M; Puranik, V D

    2013-03-01

    A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of (232)Th, (238)U, (226)Ra, (40)K and (137)Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 µSv y(-1), respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 µSv y(-1). The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from (226)Ra for cereals and drinking water and (40)K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide (137)Cs to the total dose was found to be minimum. (226)Ra was found to be the largest contributor to ingestion dose from all sources. PMID:22802517

  14. Determination of (226)Ra, (232)Th, (40)K, (235)U and (238)U activity concentration and public dose assessment in soil samples from bauxite core deposits in Western Cameroon.

    PubMed

    Mekongtso Nguelem, Eric Jilbert; Moyo Ndontchueng, Maurice; Motapon, Ousmanou

    2016-01-01

    Determination of activity concentrations in twenty five (25) soil samples collected from various points in bauxite ore deposit in Menoua Division in Western of Cameroon was done using gamma spectrometry based Broad Energy Germanium (BEGe6530) detector. The average terrestrial radionuclides of (40)K, (226)Ra, (232)Th, (235)U and (238)U were measured as 671 ± 272, 125 ± 58, 157 ± 67, 6 ± 3 and 99 ± 69 Bq kg(-1), respectively. The observed activity concentrations of radionuclides were compared with other published values in the world. The outdoor absorbed dose rate in air varied from 96.1 to 321.2 nGy h(-1) with an average of 188.2 ± 59.4 nGy h(-1). The external annual effective dose rate and external hazard index were estimated as 0.23 ± 0.07 mSv year(-1) for outdoor, 0.92 ± 0.29 mSv year(-1) for indoor and 1.13 for the external hazard index, respectively. These radiological safe parameters were relatively higher than the recommended safe limits of UNSCEAR. Consequently, using of soil as building material might lead to an increase the external exposure to natural radioactivity and future applications research need to be conducted to have a global view of radioactivity level in the area before any undergoing bauxite ore exploitation. PMID:27536536

  15. Radium-226, 232Th, and 40K distribution in the environment of Kaiga of south west coast of India.

    PubMed

    Karunakara, N; Somashekarappa, H M; Avadhani, D N; Mahesh, H M; Narayana, Y; Siddappa, K

    2001-05-01

    Systematic studies on gamma radiation level and the distribution of natural radionuclides were carried out under a pre-operational survey for the establishment of baseline data on background radiation level and the distribution of radio-nuclides in the environment of Kaiga, in the south west coast of India, where a nuclear power reactor of 235 MWe has just been commissioned. The external gamma absorbed dose rates prevailing in the region were measured using a portable plastic scintillometer. Soil samples from 18 stations were collected from depth intervals of 0-5, 5-10, and 10-25 cm and analyzed for their 226Ra, 232Th, and 40K activity concentrations by gamma spectrometry employing a 90 cc PGT HpGe detector coupled to an EG&G ORTEC 8K multichannel analyzer. The activity of 226Ra was found to vary between 15.5-61.2 Bq kg(-1) with a mean value of 31.3 Bq kg(-1), that of 232Th varies between 11.4-41.9 Bq kg(-1) with a mean value of 27.5 Bq kg(-1) and of 40K between 78.3-254.8 Bq kg(-1) with a mean value of 159.9 Bq kg(-1) in 0-5 cm soil profiles of the region. The contributions of 238U, 232Th, and 40K to the total gamma absorbed dose rate were 39.9%, 40.7%, and 16.0%, respectively. The gamma absorbed dose rate in air estimated using the results of activity concentration of 226Ra, 232Th, and 40K are found to compare well with that of the direct measurement. The results of the study were compared with the literature values reported for other environs of the country as well as the world, and conclusions are drawn. PMID:11316077

  16. Diffusion of (226)Ra and (40)K radionuclides reproduced in underwater sedimentary columns in laboratory.

    PubMed

    Ligero, R A; Feria, F; Casas-Ruiz, M; Corredor, C

    2006-01-01

    The potential radiological impact of the increase of radioactive substances in the environment makes interesting the study of the migration of the contaminant radionuclides in soils and sediments, which are the last receiver system of these substances. By using a battery of sedimentary columns controlled in the laboratory, the diffusion of the (226)Ra and (40)K radionuclides has been studied, assessing their respective effective diffusion coefficients in a similar sedimentary medium. A decreasing temporal evolution is obtained, associated to the progressive 'fixation' of the radionuclides by the clay minerals of the sediment, followed by a constant tendency. A timescale of the 'fixation' by the sediment is determined, being of the order of days for (226)Ra and of the order of months for (40)K, so the progressive 'fixation' of (40)K by the clay minerals of the sediments is slower than in the case of (226)Ra. PMID:16488520

  17. {sup 40}K, {sup 115}Cs and {sup 226}Ra Soil and Plant Content in Seminatural Grasslands of Central Argentina

    SciTech Connect

    Ayub, J. Juri; Velasco, R. H.; Rizzotto, M.; Quintana, E.; Aguiar, J.

    2008-08-07

    Activity concentrations of {sup 40}K, {sup 226}Ra and {sup 137}Cs have been analyzed in soil and plant samples, collected in permanent grassland in central Argentina. Two near areas (A1 and A2) under field conditions with soil undisturbed at least in the last four decades were selected. For each of the three studied radionuclides we do not find differences in the inventories between both areas. The inventories range from 143 kBq m{sup -2} to 197 kBq m{sup -2} for {sup 40}K and from 13 kBq m{sup -2} to 18 kBq m{sup -2} for {sup 226}Ra. The vertical distributions of {sup 40}K and {sup 226}Ra are uniform through de soil profile. For {sup 137}Cs the inventories range from 0.33 kBq m{sup -2} to 0.73 kBq m{sup -2}. In spite of {sup 137}Cs inventories are similar in both areas the distribution through vertical profile is different. {sup 137}Cs activity concentration has a maximum for layers 5-10 cm depth in A1 and 10-15 cm depth in A2. For deeper layers both areas show similar activity concentrations. The diffusion coefficient (D{sub s}) and convection velocity (v{sub s}) are estimated with a convection-diffusion model. D{sub s} values are in the range reported in the bibliography, while v{sub s} values are one order of magnitude higher. After 40 years most {sup 137}Cs fallout is still in the layer 10-15 cm depth. The great penetration of {sup 137}Cs (25 cm) in these soils may be the result of a high sand and low fine materials content. {sup 137}Cs and {sup 226}Ra were not detected in grass samples. Activity concentration of {sup 40}K in vegetal samples ranges from 116 Bq kg{sup -1} to 613 Bq kg{sup -1}. The TF values obtained for {sup 40}K show a lognormal distribution and ranges from 0.05 to 0.42.

  18. Measurement of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs in foodstuffs samples collected from coastal areas of China.

    PubMed

    Tuo, Fei; Zhang, Qing; Zhou, Qiang; Xu, Cuihua; Zhang, Jing; Li, Wenhong; Zhang, Jianfeng; Su, Xu

    2016-05-01

    This study represents a total of 245 samples collected. The activities of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs were determined in samples of vegetables, tea, cereal (rice, wheat and corn), meat, poultry, freshwater product, seafood and seaweed that collected from the 30km safety zone of the Nuclear Power Plants (NPPs) area. All the samples radionuclide activities were quantified by using High Purity Germanium (HPGe) gamma spectrometry. The geometric mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.13, 0.16, 0.11, 68 and 0.02, respectively. The arithmetic mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.34, 0.65, 0.32, 111 and 0.09, respectively. Results of this study were compared with others, the measured values are the same with those of a previous investigation. Radiation doses due to the consumption of these foodstuffs to humans are estimated to comprise around 37-46% of the annual dose limit for public. PMID:26926376

  19. Primordial radioactivity ((238)U, (232)Th and (40)K) measurements for soils of Ludhiana district of Punjab, India.

    PubMed

    Badhan, K; Mehra, R

    2012-11-01

    The aim of the present work was to study the activity concentration and absorbed gamma dose rates due to primordial radionuclides ((238)U, (232)Th and (40)K) for the soil of different villages of Ludhiana district of Punjab, India using a high-purity germanium detector based on high resolution gamma-ray spectrometry. The average activity concentrations of (238)U, (232)Th and (40)K in the soil samples have been found to be 28.58, 50.95 and 569.59 Bq kg(-1), respectively, which gives the total gamma dose rate contribution of 68.50 nGy h(-1). To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate and the effective dose rate have been calculated. The calculated radium equivalent activity values are on the lower side of the recommended safe limit value of 370 Bq kg(-1) by Organization of Economic and Control Department. The calculated value of external health hazard index is lower than unity. PMID:22899219

  20. Distribution and possible dietary intake of radioactive 137Cs, 40K and 226Ra with the pantropical mushroom Macrocybe gigantea in SW China.

    PubMed

    Falandysz, Jerzy; Zhang, Ji; Zalewska, Tamara; Apanel, Anna; Wang, Yuanzhong; Wiejak, Anna

    2015-01-01

    There is scarcity of data on contamination with radiocesium 134/137Cs of edible mushrooms from the Southwestern Asia. This study aimed to get insight into activity concentration of artificial nuclides 134/137Cs and natural 40K and 226Ra in mushrooms from Yunnan province, which is major producer in China. The specimens of pantropical mushroom Macrocybe gigantea were collected from the wild and from a farm across Yunnan land in 2012-2013 and analyzed using gamma spectrometry with hyperpure germanium coaxial detector (HPGe). M. gigantea showed low activity concentrations of 137Cs (median value for dehydrated caps was 4.5 Bq kg(-1) and 5.4 Bq kg(-1) for stipes) while 134Cs was not detected. Natural radionuclide 40K showed 2-3 orders of magnitude greater activity concentration compared to artificial 137Cs in M. gigantea. The activity concentrations of 226Ra from uranium and radium decay series for most of the consignments of M. gigantea examined were below the method's limit of detection. The nominal effective dose equivalent for the Yunnan people from the dietary intake of 137Cs was assessed to be below 0.01 μSv per annum on the average, and that from 40K to be below 0.1 μSv per annum. Data available for the first time on activity concentrations of 137Cs in wild-grown saprobic mushroom from this region of Asia suggest low pollution with radiocesium from fallout there. Hence, the likely health risks from intake of 137Cs from cooked M. gigantea are in practice of mushrooms absent for human consumers there. Because of abundance of mushrooms in Yunnan and high significance of the region as producer and exporter a wider study using many species is necessary to fill a gap on possible radioactive contamination and risk to mushroom consumers. PMID:26061207

  1. Soil to rice transfer factors for (226)Ra, (228)Ra, (210)Pb, (40)K and (137)Cs: a study on rice grown in India.

    PubMed

    Karunakara, N; Rao, Chetan; Ujwal, P; Yashodhara, I; Kumara, Sudeep; Ravi, P M

    2013-04-01

    India is the second largest producer of rice (Oryza sativa L.) in the world and rice is an essential component of the diet for a majority of the population in India. However, detailed studies aimed at the evaluation of radionuclide transfer factors (F(v)) for the rice grown in India are almost non-existent. This paper presents the soil to rice transfer factors for natural ((226)Ra, (228)Ra, (40)K, and (210)Pb) and artificial ((137)Cs) radionuclides for rice grown in natural field conditions on the West Coast of India. A rice field was developed very close to the Kaiga nuclear power plant and the water required for this field was drawn from the cooling water discharge canal of the power plant. For a comparative study of the radionuclide transfer factors, rice samples were also collected from the rice fields of nearby villages. The study showed that the (226)Ra and (228)Ra activity concentrations were below detection levels in different organs of the rice plant. The soil to un-hulled rice grain (40)K transfer factor varied in the range of 6.5 × 10(-1) to 2.9 with a mean of 0.15 × 10(1), and of (210)Pb varied in the range of <1.2 × 10(-2) to 8.1 × 10(-1) with a mean of 1.4 × 10(-1), and of (137)Cs varied in the range of 6.6 × 10(-2) to 3.4 × 10(-1) with a mean of 2.1 × 10(-1). The mean values of un-hulled grain to white rice processing retention factors (F(r)) were 0.12 for (40)K, 0.03 for (210)Pb, and 0.14 for (137)Cs. Using these processing retention factors, the soil to white rice transfer factors were estimated and these were found to have mean values of 1.8 × 10(-1), 4.2 × 10(-3), and 3.0 × 10(-2) for (40)K, (210)Pb, and (137)Cs, respectively. The study has shown that the transfer of (40)K was higher for above the ground organs than for the root, but (210)Pb and (137)Cs were retained in the root and their transfer to above the ground organs of the rice plant is significantly lower. PMID:23266913

  2. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    PubMed

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values. PMID:25532871

  3. Concentrations of 238U, 234U, 235U, 232Th, 230Th, 228Th, 226Ra, 228Ra, 224Ra, 210Po, 210Pb and 212Pb in drinking water in Italy: reconciling safety standards based on measurements of gross alpha and beta.

    PubMed

    Jia, Guogang; Torri, Giancarlo; Magro, Leandro

    2009-11-01

    Some important naturally occurring alpha- and beta-radionuclides in drinking water samples collected in Italy were determined and the radiological quality evaluated. The mean activity concentrations (mBqL(-1)) of the radionuclides in the water samples were almost in the order: 26+/-36 ((234)U)>21+/-30 ((238)U)>8.9+/-15 ((226)Ra)>4.8+/-6.3 ((228)Ra)>4.0+/-4.1 ((210)Pb)>3.2+/-3.7 ((210)Po)>2.7+/-1.2 ((212)Pb)>1.4+/-1.8 ((224)Ra)> 1.1+/-1.3 ((235)U)>0.26+/-0.39 ((228)Th)>0.0023+/-0.0009 ((230)Th)>0.0013+/-0.0006 ((232)Th). The mean estimated dose (microSvyr(-1)) to an adult from the water intake was in this order: 2.8+/-3.3 ((210)Po)>2.4+/-3.2 ((228)Ra)>2.1+/-2.1 ((210)Pb)>1.8+/-3.1 ((226)Ra)>0.94+/-1.30 ((234)U)>0.70+/-0.98 ((238)U)>0.069+/-0.087 ((224)Ra)>0.036+/-0.044 ((235)U)>0.014+/-0.021 ((228)Th)>0.012+/-0.005 ((212)Pb)>0.00035+/-0.00029 ((230)Th)>0.00022+/-0.00009 ((232)Th). It is obvious that (210)Po, (228)Ra, (210)Pb and (226)Ra are the most important dose contributors in the drinking water intake. As far as the seventeen brands of analysed drinking water were concerned, the committed effective doses were in the range of 2.81-38.5 microSvyr(-1), all well below the reference level of the committed effective dose (100 microSvyr(-1)) recommended by the WHO. These data throw some light on the scale of the radiological impact on the public from some naturally occurring radionuclides in drinking water, and can also serve as a comparison for the dose contribution from artificial radionuclides released to the environment as a result of human practices. Based on the radionuclide composition in the analysed waters, comment was made on the new screening level for gross alpha activity in guidelines for drinking-water quality recommended by the WHO, 2004. PMID:19635638

  4. Determination of (238)U, (232)Th and (40)K activity concentrations in riverbank soil along the Chao Phraya river basin in Thailand.

    PubMed

    Santawamaitre, T; Malain, D; Al-Sulaiti, H A; Bradley, D A; Matthews, M C; Regan, P H

    2014-12-01

    The activity concentrations of (238)U, (232)Th and (40)K in riverbank soil along the Chao Phraya river basin was determined through gamma-ray spectrometry measurements made using a hyper-pure germanium detector in a low background configuration. The ranges of activity concentrations of (238)U, (232)Th and (40)K were found to be 13.9 ↔ 76.8, 12.9 ↔ 142.9 and 178.4 ↔ 810.7 Bq kg(-1), respectively. The anthropogenic radionuclide, (137)Cs, was not observed in statistically significant amounts above the background level in the current study. The absorbed gamma dose rate in air at 1 m above the ground surface, the outdoor annual effective dose equivalent, the values of the radium equivalent activity and the external hazard index associated with all the soil samples in the present work were evaluated. The results indicate that the radiation hazard from primordial radionuclides in all soil samples from the area studied in this current work is not significant. PMID:25195170

  5. Determination of environmental radioactivity (238U, 232Th and 40K) and indoor natural background radiation level in Chennai city (Tamilnadu State), India.

    PubMed

    Babai, K S; Poongothai, S; Punniyakotti, J

    2013-01-01

    An extensive study on the determination of the natural radioactivity ((238)U, (232)Th and (40)K) levels in soil samples of Chennai city, India has been undertaken and the results of the same are compared with the levels reported in other Indian cities as well as other parts of the world. The radioactivity content in the soil samples, the absorbed dose rate, annual effective dose equivalent, radium equivalent activity, internal and external hazard indices were calculated and compared with UNSCEAR 2000 recommended values. In addition to the above, mapping of indoor natural background gamma radiation levels has been made using thermo luminescent dosemeters throughout Chennai city and the same are reported. PMID:22847868

  6. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    NASA Astrophysics Data System (ADS)

    Abdullah, Anisa; Hamzah, Zaini; Saat, Ahmad; Wood, Ab. Khalik

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides (232Th, 238U and 40K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (Igeo) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (Hex).

  7. Determination of 40K, 232Th and 238U activity concentrations in ambient PM2.5 aerosols and the associated inhalation effective dose to the public in Jeddah City, Saudi Arabia.

    PubMed

    Zytoon, Mohamed A; Aburas, Hani M; Abdulsalam, Mohammed I

    2014-03-01

    Natural radioactivity of soil samples has been studied in many countries of the Arabian Peninsula, including Saudi Arabia. Radiological indices based on soil radioactivity have been widely used in these studies. However, there are no available data about natural radioactivity of fine aerosol particles in such countries. The objective of this study is to determine the activity concentrations of (40)K, (232)Th and (238)U in airborne PM2.5 and the associated internal inhalation radiation dose to the public in Jeddah City, Saudi Arabia. Twenty-four air samples in four locations throughout Jeddah were collected and analyzed for PM2.5 and the associated K, Th and U. The activity concentrations of the isotopes (40)K, (232)Th and (238)U were calculated. High atmospheric PM2.5 concentrations (mean: 50.81 ± 34.02 μg/m(3)) were found. The natural radioactivity associated with PM2.5 due to the isotopes (40)K, (232)Th and (238)U were 301.8 ± 76.1, 11.8 ± 4.2 and 10.8 ± 3.4 Bq/kg, respectively, and the Raeq was calculated as 44.9 ± 14.0 Bq/kg. The inhalation annual effective radiation dose to the public due to natural isotopes of the airborne PM2.5 was in the range 15.03-58.87 nSv/year, depending on the age group. Although these dose values were associated with the PM2.5 fraction only, they were higher than the world references values in air reported in the UNSCEAR, 2000 report. PMID:24462924

  8. 235U, 238U, 232Th, 40K and 137Cs activity concentrations in marine sediments along the northern coast of Oman Sea using high-resolution gamma-ray spectrometry.

    PubMed

    Zare, Mohammad Reza; Mostajaboddavati, Mojtaba; Kamali, Mahdi; Abdi, Mohammad Reza; Mortazavi, Mohammad Seddigh

    2012-09-01

    The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine (235)U, (238)U, (232)Th, (40)K and (137)Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of (235)U, (238)U, (232)Th, (40)K and (137)Cs in sediment samples ranged between 1.01 and 2.87 Bq/kg, 11.83 and 22.68 Bq/kg, 10.7 and 25.02 Bq/kg, 222.89 and 535.07 Bq/kg and 0.14 and 2.8 Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. PMID:22717321

  9. 238U- 230Th- 226Ra disequilibrium in young Mt. Shasta andesites and dacites

    NASA Astrophysics Data System (ADS)

    Volpe, Alan M.

    1992-11-01

    The paper describes 238U-series nuclides and 230Th/ 232Th ratios measured by mass spectrometry in mineral separates of young Mt. Shasta andesites and dacites. The results constrain the timing of recent calc-alkaline magma fractionation at this volcano. Hotlum, Misery Hill and Black Butte rocks show small, < 13% 230Th- 238U and < 6% 226Ra- 230Th, disequilibria. Plagioclase have 7-26% 226Ra excesses, magnetite and groundmass have 4-5% 226Ra deficits, and pyroxenes have equilibrium ( 226Ra/ 230Th) activity ratios. Internal ( 230Th)-( 238U)and Ba-normalized ( 226Ra)-( 230Th) isotope diagrams for Hotlum and Black Butte dacites suggest that closed-system Th-U and Ra-Th fractionation occurred less than 10,000 years ago. Significant 226Ra- 230Th disequilibria in the Black Butte dacite strongly suggests that this rock erupted more recently than 9400 years ago. Results for Hotlum andesites suggest a longer pre-eruption crystal residence time compared to the dacites. There may also have been recent open Ra-Th system changes in the melt composition. Initial Th/U ratios for the rocks are low (2.43-2.57), similar to those in mid-ocean ridge basalts (MORB), and preclude significant assimilation of crust with markedly different Th-U composition.

  10. Abundances of Natural Radionuclides (40K, 238U, 232Th) in Hanford and Rifle Integrated Field Research Challenge Site Sediments and the Application to the Estimation of Grain Size Distributions

    NASA Astrophysics Data System (ADS)

    Draper, K.; Ward, A. L.; Yabusaki, S.; Murray, C. J.; Greenwood, J.

    2009-12-01

    The distribution and geometry of lithofacies impact groundwater flow and solute spreading but are difficult to characterize at the scale controlling transport. We hypothesize that differences in γ-ray activity resulting from the natural distribution of 40K, 238U, and 232Th (K, U, T) are due to hydraulic separation and sorting and can be used to infer grain-size distributions at the scale of borehole γ-ray logs. The objective of this study was to investigate the feasibility of using γ-ray spectra to detect differences in grain size distributions as a means of characterizing small-scale variations in flow and reactive transport properties. The γ-ray spectra of whole and fractionated sediments from the Hanford and Old Rifle IFRC sites were characterized along with their grain size distributions. In the Hanford sediments, the abundance of K, U, and T was strongly correlated with the extent of weathering and with mean grain size. Hanford clay showed concentrations of 4%, 5.5 ppm, and 6.5 ppm for K, U, and T respectively. An increase in geometric mean diameter from 0.02 mm (clay) to 45.25 mm (very coarse gravel) showed increases in concentrations of 70% for K, 76% for U, and 83% for T. Old Rifle sediments showed no correlation between grain size and K, but there was an 81% increase in U and a 73 % increase in T. Cross plots of Th/U and Th/K also show strong correlations with grain size. The enrichment of natural isotopes with decreasing grain size is likely due to the increase in specific surface area. Thus, borehole γ-ray spectra could have a much wider application in characterizing grain separation and sorting and ultimately flow and reactive transport properties.

  11. Photofission of /sup 232/Th

    SciTech Connect

    Arruda-Neto, J.D.T.; Rigolon, W.; Herdade, S.B.; Riette, H.L.

    1984-06-01

    The bremsstrahlung-induced fission cross section of /sup 232/Th was measured in the energy region of the giant dipole resonance. The data analysis, performed in terms of the bremsstrahlung spectrum calculated in the Davies-Bethe-Maximon approximation, shows that the photofission cross section measured at Livermore is more compatible with our results than the (..gamma..,f) data from Saclay.

  12. sup 238 U- and sup 232 Th-series chronology of phonolite fractionation at Mount Erebus, Antarctica

    SciTech Connect

    Reagan, M.K. ); Volpe, A.M. ); Cashman, K.V. )

    1992-03-01

    Uranium, thorium, radium, and barium abundances and {sup 234}U/{sup 238}U and {sup 230}Th/{sup 232}Th isotopic ratios determined by thermal ionization mass spectrometry and ({sup 228}Th)/({sup 232}Th) activity ratios determined by alpha spectrometry are used to date anorthoclase growth and infer magma chamber residence times of phonolites erupted in 1984 and 1988 from Mount Erebus, Antarctica. The 1984 and 1988 glasses have slightly different ({sup 230}Th)/({sup 232}Th) ratios but both have a 10% excess of ({sup 230}Th) over ({sup 238}U) and equilibrium ({sup 228}Th) values. By comparing these data and Pb-isotopic data reported in SUN and HANSON (1975) to similar data for oceanic basalts, the duration of differentiation from basanite to phonolite is limited to less than 150,000 years. The anorthoclase separates have ({sup 230}Th)/({sup 238}U) ratios exceeding those of the associated glasses but have ({sup 230}Th)/({sup 232}Th) ratios like those of the glasses. Both glasses are depleted in {sup 226}Ra with respect to {sup 230}Th by about 25%, whereas associated anorthoclase separates have extreme excesses of {sup 226}Ra over {sup 230}Th and ({sup 228}Th)/({sup 232}Th) = 2.2. On a plot of ({sup 226}Ra)/Ba vs. ({sup 230}Th)/BA, the glass-anorthoclase pairs produce isochrons averaging 2,380 y, which represents the average age of anorthoclase growth in the shallow magma system at Erebus. The implied residence time of phonolite magmas in the shallow magma chamber system of Erebus is about 3,000 y. Final crystal growth occurred after intrusion into the convecting lava lake less than decades before eruption.

  13. Leaching of 226Ra from components of uranium mill tailings

    USGS Publications Warehouse

    Landa, E.R.

    1991-01-01

    A sequential extraction procedure was used to characterize the geochemical forms of 226Ra retained by mixtures of quartz sand and a variety of fine-grained rock and mineral species. These mixtures had previously been exposed to the sulfuric acid milling liquor of a simulated acid-leach uranium milling circuit. For most test cases, the major fraction of the 226Ra was extracted with 1 mol/1 NH4Cl and was deemed to be exchangeable. However, 226Ra retained by the barite-containing mixture was resistant to both 1 mol/1 NH4Cl and 1 mol/HCHCl extraction. ?? 1991.

  14. 226Ra in the western Indian Ocean

    NASA Astrophysics Data System (ADS)

    Chung, Y.

    1987-09-01

    226Ra profiles have been measured in the western Indian Ocean as part of the 1977-1978 Indian Ocean GEOSECS program. These profiles show a general increase in deep and bottom water Ra concentration from the Circumpolar region to the Arabian Sea. A deep Ra maximum which originates in the Arabian Sea and in the Somali basin at about 3000 m depth spreads southward into the Mascarene basin and remains discernible in the Madagascar and Crozet basins. In the western Indian Ocean, the cold Antarctic Bottom Water spreads northward under the possibly southward-flowing deep water, forming a clear benthic front along the Crozet basin across the Southwest Indian Ridge into the Madagascar and Mascarene basins. The Antarctic Bottom Water continues to spread farther north to the Somali basin through the Amirante Passage at 10°S as a western boundary current. The benthic front and other characteristic features in the western Indian Ocean are quite similar to those observed in the western Pacific where the benthic front as a distinctive feature was first described by Craig et al. [15]. Across the Mid-Indian Ridge toward the Ceylon abyssal plain near the triple junction, Ra profiles display a layered structure, reflecting the topographic effect of the mid-ocean ridge system on the mixing and circulation of the deep and bottom waters. Both Ra and Si show a deep maximum north of the Madagascar basin. Linear relationships between these two elements are observed in the deep and bottom water with slopes increasing northward. This suggests a preferential input of Ra over Si from the bottom sediments of the Arabian Sea and also from the flank sediments of the Somali basin.

  15. Radiation impact from lignite burning due to 226Ra in Greek coal-fired power plants.

    PubMed

    Papastefanou, C

    1996-02-01

    Lignite contains naturally occurring radionuclides arising from the uranium and thorium series as well as from 40K. Lignite burning is, therefore, one of the sources of technologically enhanced exposure to humans from natural radionuclides. Emissions from thermal power stations in gaseous and particulate form contain radioisotopes, such as 226Ra, that are discharged into the environment causing radiation exposures to the population. About 11,672 MBq y-1 of 226Ra are discharged into the environment from four coal-fired power plants totalling 3.62 GW electrical energy in the Ptolemais Valley, Northern Greece, in which the combustion of 1.1 x 10(10) kg of lignite is required to produce an electrical energy of 1 GW y. The collective committed equivalent dose to lung tissue per unit power generated resulting from atmospheric releases of 226Ra was estimated to be 1.1 x 10(-2) person Sv (GW y)-1; i.e. more than 15 times higher than the average value for a modern type coal-fired power plant according to the UNSCEAR 1988 data. PMID:8567285

  16. Concentration of {sup 226}Ra in human teeth

    SciTech Connect

    Yamamoto, Masayoishi; Ueno, Kaoru; Hinoide, Moriyo; Ohkubo, Yoshiteru

    1994-11-01

    {sup 226}Ra concentrations in human teeth from several cities, mainly Tokyo, Japan, were determined with emphasis on the measurement of low-level {sup 226}Ra by alpha-ray spectrometry following chemical separation. No appreciable differences in {sup 226}Ra concentration were found among various permanent teeth samples of different age groups in Tokyo. The mean {sup 226}Ra concentration for Tokyo was 0.51 {+-} 0.06 mBq (g CA){sup -1}. {sup 226}Ra concentration [mean: 0.67 {+-} 0.11 mBq (g Ca){sup -1}] in teeth in western regions of the country was statistically higher than that [mean: 0.48 {+-} 0.09 mBq (g Ca){sup -1}] in eastern ones. The mean {sup 226}Ra concentration [0.51 mBq (g CA){sup -1}] in teeth from Tokyo was less than the concentration [1.11 mBq (g CA){sup -1}] reported for vertebral bone samples of this city. 27 refs., 1 fig., 5 tabs.

  17. Rapid determination of 226Ra in emergency urine samples

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B.; Utsey, Robin C.; McAlister, Daniel R.

    2014-02-27

    A new method has been developed at the Savannah River National Laboratory (SRNL) that can be used for the rapid determination of 226Ra in emergency urine samples following a radiological incident. If a radiological dispersive device event or a nuclear accident occurs, there will be an urgent need for rapid analyses of radionuclides in urine samples to ensure the safety of the public. Large numbers of urine samples will have to be analyzed very quickly. This new SRNL method was applied to 100 mL urine aliquots, however this method can be applied to smaller or larger sample aliquots as needed.more » The method was optimized for rapid turnaround times; urine samples may be prepared for counting in <3 h. A rapid calcium phosphate precipitation method was used to pre-concentrate 226Ra from the urine sample matrix, followed by removal of calcium by cation exchange separation. A stacked elution method using DGA Resin was used to purify the 226Ra during the cation exchange elution step. This approach combines the cation resin elution step with the simultaneous purification of 226Ra with DGA Resin, saving time. 133Ba was used instead of 225Ra as tracer to allow immediate counting; however, 225Ra can still be used as an option. The rapid purification of 226Ra to remove interferences using DGA Resin was compared with a slightly longer Ln Resin approach. A final barium sulfate micro-precipitation step was used with isopropanol present to reduce solubility; producing alpha spectrometry sources with peaks typically <40 keV FWHM (full width half max). This new rapid method is fast, has very high tracer yield (>90 %), and removes interferences effectively. The sample preparation method can also be adapted to ICP-MS measurement of 226Ra, with rapid removal of isobaric interferences.« less

  18. Determination of 226Ra in urine samples by alpha spectrometry.

    PubMed

    Kehagia, K; Potiriadis, C; Bratakos, S; Koukouliou, V; Drikos, G

    2007-01-01

    A radiation protection system to assess the internal contamination of workers during decontamination activities in an abounded fertilizer industry in the region of Attika, Greece, has been implemented. This system concerns, among other radionuclides, 226Ra. Because of the low 226Ra activities in urine, alpha spectrometry was used as the determination method after radiochemical separation. Radium was co precipitated with lead sulphate and purified using anion and cation exchange techniques. The source for the alpha spectrometric measurement was prepared by the electrodeposition of radium, from an aqueous/ethanol solution, onto stainless steel. The tracer used was 229Th. The chemical yield and the activity concentration were calculated via its daughter radionuclide 217At. Using the time-evolution formulas to calculate the 217At growth from its parent radionuclide 225Ra, a computer software was developed. This software was incorporated in a database, which automatically calculates and stores the results. PMID:17827131

  19. Metrological Determination of Natural Radioactive Isotopes {sup 226}Ra, {sup 228}Ra and {sup 210}Pb by Means of Ge Detector

    SciTech Connect

    Almeida, Maria Candida M. de; Delgado, Jose U.; Poledna, Roberto; Oliveira, Estela Maria de; Silva, Ronaldo L. da

    2008-08-07

    A metrological method to determine the activity per mass unity (activity concentration) of {sup 226}Ra and {sup 210}Pb ({sup 238}U decay series) and {sup 228}Ra ({sup 232}Th series) by gamma-ray spectrometers based on hyper-pure coaxial germanium detector was developed. In the soil the {sup 22}Ra (half-life = 1600 years) exhibits the same level of radioactivity as {sup 238}U (half-life 4.5x10{sup 9} years) because of a natural phenomenon called secular equilibrium. {sup 226}Ra decays into {sup 222}Rn (half-life = 3.8 days), a radioactive inert gas. After several days, the {sup 222}Rn naturally decays to {sup 218}Po (half-life = 3 minutes), where finally {sup 210}Pb (half-life = 22 years) is produced. The metrological capability of high-resolution gamma-ray spectrometry for naturally occurring radionuclides at environmental levels is showed, with emphasis on the use of 2 mL standard sources volume in a glass ampoule. Source preparation and calibration procedures are described. Radionuclide standards in an activity range of 10 to 250 Bq/g were produced which can be applied in a variety of environmental sample analysis (water, plant material, sediment, etc.). Uncertainties for {sup 226}Ra and {sup 210}Pb around 3% (k = 1) were obtained.

  20. Radon concentration in soil gas and its correlations with pedologies, permeabilities and 226Ra content in the soil of the Metropolitan Region of Belo Horizonte - RMBH, Brazil

    NASA Astrophysics Data System (ADS)

    Lara, E.; Rocha, Z.; Palmieri, H. E. L.; Santos, T. O.; Rios, F. J.; Oliveira, A. H.

    2015-11-01

    The radon concentration in soil gas is directly dependent on the geological characteristics of the area, such as lithology, pedology and on geochemicals, physicals and mineralogicals parameters of the soil. This paper looks for correlations between radon concentrations in soil gas and its soil permeability, 238U, 232Th and 226Ra contents in the soil groups classified by pedologies of Metropolitan Region of Belo Horizonte (RMBH), Minas Gerais, Brazil. The soil gas radon concentrations were determined by using an AlphaGUARD® monitor at about 150 measurement points. In soil samples of the same measurement points, the concentrations of 226Ra were determined by gamma spectrometry (HPGe), and 238U and 232Th by ICP-MS. The soil permeabilities were determined by using the RADON-JOK® permeameter. The mean concentrations of radon in soil gas ranged from 13.6±3.0 kBq m-3 for Litholic Neosols until 60.6±8.7 kBq m-3 for Perferric Red Latosols. The mean of 226Ra activity concentrations presented variation of 12.4±2.5 Bq kg-1 for Litholic Neosols until 50.3±13 Bq kg-1 for Perferric Red Latosols. Approximately 40% of the soils presented high permeability. The areas of different pedologies were classified by Soil Radon Index (SRI), determined by the soil gas radon concentration and permeability. Approximately 53% of the Perferric Red Latosols measurement site could be classified as "High Risk" (Swedish criteria). The preliminary results may indicate an influence of iron formations present very close to the Perferric Red Latosols in the retention of uranium minerals, and hence an increase in the concentration of radon and radium, whereas the series are in equilibrium in the environment.

  1. Sources of alluvium in a coastal plain stream based on radionuclide signatures from the 238U and 232Th decay series

    NASA Astrophysics Data System (ADS)

    Yeager, Kevin M.; Santschi, Peter H.; Phillips, Jonathan D.; Herbert, Bruce E.

    2002-11-01

    Discerning alluvial sources and their change over time or distance is a fundamental question in hydrology and geology, often critical in identifying impacts of human and natural perturbations on fluvial systems. Surfaces of upland interfluves and subsoils, sources of alluvium in the lower Loco Bayou basin, Texas, were distinguished using the isotope ratios 226Ra/232Th, 226Ra/230Th, and 230Th/232Th. Channel alluvium indicates a transition from interfluve surface to subsoil sources during flood (subsoil ˜34% to ˜91%, over about 8 km) and bank-full stages (subsoil ˜9% to ˜74%, over about 12 km), with distance downstream. These results indicate strong coupling between hillslope and channel processes, reflecting land use change from forested to agricultural, concentrated in lower Loco Bayou. This methodology shows that sediment sources can be differentiated based upon landscape placement where lithologic contrast is absent. The geochemistry, long half-lives, and fractionation of 238U and 232Th decay series radionuclides during pedogenic and fluvial processes in humid climates suggest that these methods are applicable in a wide variety of fluvial systems.

  2. Radium content and the 226Ra /228Ra activity ratio in groundwater from bedrock

    NASA Astrophysics Data System (ADS)

    Asikainen, Matti

    1981-08-01

    The relative abundance of 226Ra and 228Ra were determined in the groundwater from 125 drilled wells containing from < 0.1 to 51.3 pCi/l of 226Ra. The determination of 228Ra was carried out with a liquid scintillation counter by measuring only the weakly energetic β particles emitted from 228Ra. Thus the interference from the daughter nuclides of 226Ra was avoided, without specific separation of 228Ac. The direct measurement of 228Ra made the method decisively simpler and faster in terms of the chemistry involved. The concentration of 228Ra was found to be independent of the amount of 226Ra present in the samples. The concentrations of 228Ra were nearly the same over the whole range of 226Ra concentrations and the average sol 226Ra /228Ra ratio sharply increased as the 226Ra content of water increased. The 226Ra /228Ra ratio in the drilled wells varied from 0.3 to 26. Abnormally high 226Ra /228Ra ratios were found in areas with known uranium deposits as well as in several drilled wells at other locations. The abnormally high 226Ra /228Ra ratios present in groundwater suggest that the radioactivity anomaly is caused by uranium deposits and not by common rocks. In samples with a low radioactivity level the average 226Ra /228Ra ratio was slightly below unity, corresponding to the typical U/ Th ratio of granite, the most common kind of rock in the study area. The samples from the rapakivi area proved to be exceptional in that they had a low 226Ra /228Ra ratio independent of the concentration of 226Ra.

  3. 226Ra or 226Ra/Ba dating of Holocene volcanic rocks: application to Mt. Etna and Merapi volcanoes

    NASA Astrophysics Data System (ADS)

    Condomines, M.; Gauthier, P. J.; Tanguy, J. C.; Gertisser, R.; Thouret, J. C.; Berthommier, P.; Camus, G.

    2005-02-01

    This paper shows how 226Ra- 230Th disequilibria can be used to date Holocene volcanic rocks from some well selected volcanoes. A systematic study of these disequilibria on historical or well-dated volcanic samples is indeed first required to test the applicability of this method. Two examples are described here to illustrate its potential. In the case of Mt. Etna, the good correlation observed between ( 226Ra) 0 activities at the time of eruption and Th contents in lava flows from the last two millennia [M. Condomines, J.C. Tanguy, V. Michaud, Magma dynamics at Mt. Etna: constraints from U-Th-Ra-Pb radioactive disequilibria and Sr isotopes in historical lavas, Earth Planet. Sci. Lett. 132 (1995) 25-41] is used to infer the ages of several newly analysed lava flows. The calculated ages are in good agreement with those deduced from the archaeomagnetic curve describing the variation of the geomagnetic field direction in southern Italy [J.C. Tanguy, I. Bucur, J.F.C. Thompson, Geomagnetic secular variation in Sicily and revised ages of historic lavas from Mt. Etna, Nature 318 (1985) 453-455, J.C. Tanguy, M. Le Goff, V. Chillemi, A. Paiotti, C. Principe, S. La Delfa, G. Patane, Variation séculaire de la direction du champ géomagnétique enregistrée par les laves de l'Etna et du Vésuve pendant les deux derniers millénaires, C. R. Acad. Sci. Paris 329 (1999) 557-564, J.C. Tanguy, M. Le Goff, C. Principe, S. Arrighi, V. Chillemi, A. Paiotti, S. La Delfa, G. Patane, Archaeomagnetic dating of Mediterranean volcanics of the last 2100 years: validity and limits. Earth Planet. Sci. Lett. 211 (2003) 111-124]. We also present a whole set of new U-series data on historical, recent, and older samples from Merapi (Indonesia), and show that the ( 226Ra)/Ba ratio has probably maintained a quasi-steady state value during at least the past four millennia, and can be used to infer the ( 226Ra) 0/Ba ratio of old volcanics at the time of eruption, and thus their ages. Comparison with

  4. Study of soil-plant transfer of 226Ra under greenhouse conditions.

    PubMed

    Soudek, Petr; Petrová, Sárka; Benesová, Dagmar; Kotyza, Jan; Vágner, Martin; Vanková, Radomíra; Vanek, Tomás

    2010-06-01

    A soil-plant transfer study was performed using soil from a former uranium ore processing factory in South Bohemia. We present the results from greenhouse experiments which include estimates of the time required for phytoremediation. The accumulation of (226)Ra by different plant species from a mixture of garden soil and contaminated substrate was extremely variable, ranging from 0.03 to 2.20 Bq (226)Ra/g DW. We found differences in accumulation of (226)Ra between plants from the same genus and between cultivars of the same plant species. The results of (226)Ra accumulation showed a linear relation between concentration of (226)Ra in plants and concentration of (226)Ra in soil mixtures. On the basis of these results we estimated the time required for phytoremediation, but this appears to be too long for practical purposes. PMID:18823682

  5. Rapid method for the determination of 226Ra in hydraulic fracturing wastewater samples

    DOE PAGESBeta

    Maxwell, Sherrod L.; Culligan, Brian K.; Warren, Richard A.; McAlister, Daniel R.

    2016-03-24

    A new method that rapidly preconcentrates and measures 226Ra from hydraulic fracturing wastewater samples was developed in the Savannah River Environmental Laboratory. The method improves the quality of 226Ra measurements using gamma spectrometry by providing up to 100x preconcentration of 226Ra from this difficult sample matrix, which contains very high levels of calcium, barium, strontium, magnesium and sodium. The high chemical yield, typically 80-90%, facilitates a low detection limit, important for lower level samples, and indicates method ruggedness. Ba-133 tracer is used to determine chemical yield and correct for geometry-related counting issues. The 226Ra sample preparation takes < 2 hours.

  6. 226Ra/238U disequilibrium in an upland organic soil exhibiting elevated natural radioactivity.

    PubMed

    Dowdall, Mark; O'Dea, John

    2002-01-01

    This paper presents the results of a study into the anomalous 226Ra/238U disequilibrium (226Ra/238U of 0.5-9) exhibited by an upland organic soil in Co. Donegal, Ireland. Radiochemical speciation of 226Ra, 238U and 225Ra indicates that in this organic soil the high 226Ra/238U ratio is due to loss of 235U relative to 226Ra via oxidation and mobilisation of 238U in the upper layers of the soil and subsequent loss in solution. At the lower, more reducing depths of the soil profile, 238U and 226Ra are essentially in equilibrium. Loss of 238U appears to occur primarily from the easily oxidised organic and iron oxide fractions of the soil, samples exhibiting high 226Ra/238U ratios displaying significantly lower 238U levels in these fractions than samples whose ratio is below the average value for the soil of the valley. Selective enrichment of 226Ra by plants or preferential leaching of 226Ra from the underlying rock is not supported by the results of this study. PMID:11848154

  7. A correlation between soil descriptions and {sup 226}Ra concentrations in Florida soils

    SciTech Connect

    Harrison, D.P.

    1992-12-31

    The soil radium content in Florida is highly variable. The range in radium concentrations, where the samples involved in this study are concerned, is from 0.1 pCi/g to 18.5 pCi/g. Low {sup 226}Ra concentrations (0.1 to 5 pCi/g) are evidenced in sands, moderate concentrations (5 to 11 pCi/g) are found in silt and gravel, and high {sup 226}Ra concentrations (>11 pCi/g) are found in soil horizons with shell, clay, and strata with phosphate. Strata containing phosphate yields a high concentration of {sup 226}Ra. The information obtained in this study, soil descriptions with their corresponding {sup 226}Ra concentrations, comes from geological cores drilled by geotechnical consultants with gamma spectrometry analysis performed by high resolution gamma spectroscopy. Concentration; of {sup 226}Ra generally increase with depth. These cores are usually terminated at 20 feet deep, with some cores being shallower than this due to hitting bedrock or encountering the water table. These frequency distributions give the core-logging geologist an approximate concentration of {sup 226}Ra based on the description of the soil. Since the correlation of {sup 226}Ra and soil descriptions can be used as a tool in assigning indoor radon potential, this study is of importance to land managers, contractors, developers, and regulating agencies who are attempting to place standards on tracts of land with {sup 226}Ra concentration used as a criterion.

  8. Photofission cross section of /sup 232/Th

    SciTech Connect

    Zhang, H.X.; Yeh, T.R.; Lancman, H.

    1986-10-01

    The photofission cross section of /sup 232/Th was measured in the 5.8-12 MeV energy range with an average photon energy resolution of 600 eV. Intermediate structure was observed at 5.91, 5.97, and 6.31 MeV. The experimental fission probability and various properties of the intermediate structure were compared with calculated values based on a double-humped fission barrier as well as a triple-humped one. The results favor, though not decisively, the presence of a shallow third well in the barrier. Certain features of both barriers, a rather high first hump and a deep secondary well, are quite different from those predicted by current theoretical barrier calculations.

  9. Lifetime Measurements of Trapped ^232Th^3+

    NASA Astrophysics Data System (ADS)

    Depalatis, Michael; Chapman, Michael

    2012-06-01

    In recent years, there has been considerable interest in the low lying nuclear isomer state of ^229Th which is only several eV above the nuclear ground state [1]. To date, several groups are taking a variety of approaches to finding and exciting this unique state [2], including the use of trapped Th^3+ ions. Despite this attention, few precise measurements have been made of atomic lifetimes. In this work we present experiments to measure the 6D3/2 and 6D5/2 states using laser cooled ^232Th^3+ confined in a linear Paul trap.[4pt] [1] E. Peik and Chr. Tamm, Europhys. Lett. 61, 181 (2003); V. V. Flambaum, Phys. Rev. Lett. 97, 092502 (2006); B. R. Beck et al., Phys. Rev. Lett. 98, 142501 (2007).[0pt] [2] W. G. Rellergert et al., Phys. Rev. Lett. 104, 200802 (2010); S. G. Porsev et al., Phys. Rev. Lett. 105, 182501 (2010); C. J. Campbell et al., Phys. Rev. Let. 106, 223001 (2011).

  10. A Study on Sorption of (226)Ra on Different Clay Matrices.

    PubMed

    Alhajji, E; Al-Masri, M S; Khalily, H; Naoum, B E; Khalil, H S; Nashawati, A

    2016-08-01

    The sorption of radium 226 ((226)Ra) on different clay materials (bentonite, illite and a mixture of bentonite-illite) was studied. Clay materials are used in the construction of disposal pits for technically enhanced naturally occurring radioactive materials (TENORM) wastes (i.e., contaminated soil and sludge) generated by the oil and gas industry operations. Experimental conditions (pH, clay materials quantity, and activity concentrations of (226)Ra) were changed in order to determine the optimal state for adsorption of (226)Ra. The results showed that the concentration of adsorbed (226)Ra on clay materials increased with time to reach an equilibrium state after approximately 5 h. More than 95 % of the radium was adsorbed. The mixture of bentonite-illite (1/9) exhibited the greatest adsorption of radium under all experimental conditions. PMID:27329110

  11. Behavior of /sup 226/Ra in the Mississippi River mixing zone

    SciTech Connect

    Moore, D.G.; Scott, M.R.

    1986-12-15

    The behavior of /sup 226/Ra in the Mississippi River mixing zone is strongy nonconservative and includes desorption similar to that for the Hudson, Pee Dee, and Amazon rivers. However, dissolved and desorbed /sup 226/Ra concentrations in the Mississippi are 2 to 5 times greater than in the other rivers at the same salinity. Radium concentrations vary inversely with the water discharge rate. The /sup 226/Ra desorption maximum occurs at a salinity of 5.0, much lower than the 18 to 28 salinity values for the maxima of the other three rivers. High concentrations of dissolved /sup 226/Ra (up to 82 dpm per 100 L) and the low salinity values for the desorption maximum in the Mississippi River result from three major factors. Suspended sediments include a large fraction of montmorillonite, which gives the sediment a high cation exchange capacity. 0.54 meq/g. The average suspended sediment load is large, about 510 mg/L, and contains 1.9 dpm g desorbable /sup 226/Ra. The dissolved /sup 226/Ra river water end-member (9.6 dpm per 100 L) is higher than in surface seawater. The annual contribution of /sup 226/Ra to the ocean from the Mississippi River is 3.7 x 10/sup 14/ dmp/yr based on data from three cruises. Evidence of flux of /sup 226/Ra from estuarine and shelf sediments is common in vertical profile sampling of the deltaic waters but is not reflected in calculations made with an ''apparent'' river water Ra value extrapolated to zero salinity.

  12. 226Ra bioavailability to plants at the Urgeiriça uranium mill tailings site.

    PubMed

    Madruga, M J; Brogueira, A; Alberto, G; Cardoso, F

    2001-01-01

    Large amounts of solid wastes (tailings) resulting from the exploitation and treatment of uranium ore at the Urgeiriça mine (north of Portugal) have been accumulated in dams (tailing ponds). To reduce the dispersion of natural radionuclides into the environment, some dams were revegetated with eucalyptus (Eucalyptus globolus) and pines (Pinus pinea). Besides these plants, some shrubs (Cytisus spp.) are growing in some of the dams. The objective of this study is to determine the 226Ra bioavailability from uranium mill tailings by quantifying the total and available fraction of radium in the tailings and to estimate its transfer to plants growing on the tailing piles. Plant and tailing samples were randomly collected and the activity concentration of 226Ra in plants (aerial part and roots) and tailings was measured by gamma-spectrometry. The exchangeable fraction of radium in tailings was quantified using one single step extraction with 1 mol dm-3 ammonium acetate (pH = 7) or 1 mol dm-3 calcium chloride solutions. The results obtained for 226Ra uptake by plants show that 226Ra concentration ratios for eucalyptus and pines decrease at low 226Ra concentrations in the tailings and appear relatively constant at higher radium concentrations. For shrubs, the concentration ratios increase at higher 226Ra solid waste concentrations approaching a saturation value. Percentage values of 16.0 +/- 8.3 and 12.9 +/- 8.9, for the fraction of radium extracted from the tailings, using 1 mol dm-3 ammonium acetate or calcium chloride solutions, respectively, were obtained. The 226Ra concentration ratios determined on the basis of exchangeable radium are one order of magnitude higher than those based on total radium. It can be concluded that, at a 95% confidence level, more consistent 226Ra concentration ratios were obtained when calculated on the basis of available radium than when total radium was considered, for all the dams. PMID:11379070

  13. Distribution and retention in bone of /sup 226/Ra and comparison with the ICRP 20 model

    SciTech Connect

    Holtzman, R.B.; Rundo, J.; Sha, J.Y.; Spaletto, M.I.

    1981-01-01

    Analyses are presented of the ratios of /sup 226/Ra to calcium in over 650 samples of compact and cancellous bone from 66 female and 26 male subjects who had died from less than one to 60 years after first exposure to radium. The /sup 226/Ra/Ca ratios were normalized to the terminal /sup 226/Ra skeletal content. The /sup 226/Ra/Ca ratios for vertebrae were essentialy identical to those for other cancellous bone for a given subject. Comparisons of the data with predictions of the ICRP model of alkaline earth metabolism show that for female cancellous bone the normalized /sup 226/Ra/Ca ratios tended to be greater than predicted, while those for female cortical bone (femoral and tibial shaft) tended to be less. The data for males were fitted better by the model. A modification of the model to reduce the amount of radium deposited in soft tissue fitted the data better in some respects. A straight line linear least squares fit to the data appeared to fit as well as, or better than, the models. A radiation effect was suggested in that the normalized /sup 226/Ra/Ca ratio for vertebrae relative to the ratio expected increased with skeletal absorbed dose for vertebra. However, no such effect was apparent for compact bone or for the cancellous bone as a whole.

  14. Simultaneous determination of 226Ra, 233U and 237Np by liquid scintillation spectrometry.

    PubMed

    Nebelung, Cordula; Baraniak, Lutz

    2007-02-01

    A method has been developed for the simultaneous determination of 226Ra, 233U and 237Np by liquid-scintillation (LS) spectrometry. This method consists of the evaluation of the alpha-spectrum that is composed of the strongly overlapping peaks of 226Ra, 233U, 237Np, 222Rn and 218Po in the energy range of 4.60-6.00 MeV and the single 214Po peak at 7.69 MeV. The alpha-peaks are analysed by a special peak fit function that considers the deviation of the alpha-peak at the low energy side from the pure Gaussian shape. First 237Np is determined using its daughter 233Pa by analysing the beta-spectrum in the range 150-570 keV. 226Ra follows from the alpha-spectrum that is measured 6 weeks after sample preparation, i.e., 226Ra is determined from the radioactive equilibrium with its short-lived daughters 222Rn, 218Po and 214Po. Finally the 233U activity results from the fitted spectrum in the range of 4.4-4.8 MeV by subtracting the activity of 226Ra and 237Np. Knowing the exact energy position of the LS-peaks an alternative evaluation consists in the accurate deconvolution of the first three peaks that are formed by 226Ra and 233U (maximum of both at channel 700), 237Np (maxima at channels 700 and 725) and 222Rn (maximum at channel 737). In these two ways 226Ra, 233U and 237Np can be determined in mutual activity ratios of 1:50 with a relative standard deviation of less than 4% for the major activity and 9% for the minor activity. PMID:17142052

  15. Comparative Analysis Of 226Ra Soil-To-Plant Transfer In Cabbage Grown In Various Regions

    NASA Astrophysics Data System (ADS)

    Madruga, M. J.; Carvalho, F. P.; Silva, L.; Gouveia, J.

    2008-08-01

    The transfer of 226Ra from soil to cabbage was compared amongst regions, namely the surroundings of Urgeiriça uranium milling tailings (GE), regions with past uranium mining activities (GN1), and regions with no uranium mining activities and no uranium deposits (GN2). Results show a slight increase of the concentration ratio values at low radium concentration in soils. Statistical analysis of the mean 226Ra activity concentrations in soil and cabbage for the three regions was carried out. The comparison of 226Ra activity concentrations in soils indicated no difference (p>0.05), between GE and GN2 and significant differences (p<0.05) between GE and GN1 and between GN1 and GN2. Similar statistical results were obtained for 226Ra activity concentrations in cabbage from the same regions. It was concluded that radium Concentration Ratio (CR) for cabbage grown in the region of the main uranium milling site (GE) is of the same order of magnitude of CR in cabagge grown in background regions (GN2). However, 226Ra CR was higher in cabagge from the region with past uranium mining activities (GN1).

  16. Sorption of (226)Ra from oil effluents onto synthetic cation exchangers.

    PubMed

    Al Attar, Lina; Safia, Bassam

    2013-07-30

    Increasing environmental awareness is being urged for the safe disposal of (226)Ra-contaminated production water generated in the oil industry. Birnessite, antimony silicate and their cationic derivatives were studied for the take-up of (226)Ra using the batch-type method under experimentally determined parameters, viz. contact time, solution-solid ratio and (226)Ra concentration. Data was expressed in terms of distribution coefficients. Sorption experiments were performed in different concentrations of nitric acid in order to speculate the mechanism of (226)Ra uptake. Variation in the magnitude of sorption efficiency of the materials in the presence of the major components of waste streams, i.e. Na(+), K(+) and Ca(2+), revealed that K(+) was the greatest competitor and Na(+) the least. The application of the materials to sorb (226)Ra from actual oil co-production water samples, collected from Der Ezzor and Al Fourat petroleum companies (DEZPC and AFPC), was interpreted in terms of the exchange properties of the materials and water characterisation. Of the parameters studied, the selectivity of materials was shown to be greatly dependent on the pH of wastewater to be treated. PMID:23623032

  17. Transfer coefficient of 226Ra from vegetation to meadow voles, Microtus pennsylvanicus, on U mill tailings

    SciTech Connect

    Cloutier, N.R.; Clulow, F.V.; Lim, T.P.; Dave, N.K.

    1986-06-01

    The 226Ra level in vegetation growing on U mine tailings in Elliot Lake, Ontario, Canada, was 211 + 22 mBq g-1 (dry weight) compared to less than 7 mBq g-1 (dry weight) in material from a control site. Skeletons of meadow voles (Microtus pennsylvanicus) established on the tailings had concentrations of 226Ra of 6083 +/- 673 mBq per animal in winter; 7163 +/- 1077 mBq per animal in spring; 1506 +/- 625 mBq per animal in summer; and 703 +/- 59 mBq per animal in fall, compared to less than 7 mBq per animal in controls. The /sup 226/Ra transfer coefficient from vegetation to voles (defined as total millibecquerels of /sup 226/Ra in adult vole per total millibecquerels of 226Ra consumed by the vole in its lifetime) was calculated as 4.6 +/- 2.9 X 10(-2) in summer and 2.8 +/- 0.6 X 10(-2) in fall.

  18. Distribution and flux of /sup 226/Ra and /sup 228/Ra in the Amazon River estuary

    SciTech Connect

    Key, R.M.; Sarmiento, J.L.; Stallard, R.F.; Moore, W.S.

    1985-07-20

    Measurements of /sup 226/Ra and /sup 228/Ra in the Amazon River estuary show that desorption from riverborne suspended particulate matter in the estuary increases the riverine flux of both isotopes to the ocean by a factor of approximately 5 over the flux attributable to radium dissolved in the river water alone. The total Amazon flux supplies approximately 0.20% of the /sup 226/Ra and approximately 2.6% of the /sup 228/Ra standing crops in the near-surface Atlantic (0-200 m). Diffusive flux from estuarine and shelf sediments and desorption from resuspended sediments in the region of the estuary approximately double the estuarine /sup 226/Ra concentration and quadruple the estuarine /sup 228/Ra concentration above that caused by the dissolved and desorbed river components alone.

  19. Release of 226Ra from uranium mill tailings by microbial Fe(III) reduction

    USGS Publications Warehouse

    Landa, E.R.; Phillips, E.J.P.; Lovley, D.R.

    1991-01-01

    Uranium mill tailings were anaerobically incubated in the presence of H2 with Alteromonas putrefaciens, a bacterium known to couple the oxidation of H2 and organic compounds to the reduction of Fe(III) oxides. There was a direct correlation between the extent of Fe(III) reduction and the accumulation of dissolved 226Ra. In sterile tailings in which Fe(III) was not reduced, there was negligible leaching of 226Ra. The behavior of Ba was similar to that of Ra in inoculated and sterile systems. These results demonstrate that under anaerobic conditions, microbial reduction of Fe(III) may result in the release of dissolved 226Ra from uranium mill tailings. ?? 1991.

  20. Measuring 226Ra/228Ra in Oceanic Lavas by MC-ICPMS

    NASA Astrophysics Data System (ADS)

    Standish, J. J.; Sims, K.; Ball, L.; Blusztajn, J.

    2007-12-01

    238U-230Th-226Ra disequilibrium in volcanic rocks provides an important and unique tool to evaluate timescales of recent magmatic processes. Determination of 230Th-226Ra disequilibria requires measurement of U and Th isotopes and concentrations as well as measurement of 226Ra. While measurement of U and Th by ICPMS is now well established, few published studies documenting 226Ra measurement via ICPMS exist. Using 228Ra as an isotope spike we have investigated two ion-counting methods; a 'peak-hopping' routine, where 226Ra and 228Ra are measured in sequence on the central discrete dynode ETP secondary electron multiplier (SEM), and simultaneous measurement of 226Ra and 228Ra on two multiple ion-counter system (MICS) channeltron type detectors mounted on the low end of the collector block. Here we present 226Ra measurement by isotope dilution using the Thermo Fisher NEPTUNE MC-ICPMS. Analysis of external rock standards TML and AThO along with mid-ocean ridge basalt (MORB) and ocean island basalt (OIB) samples show three issues that need to be considered when making precise and accurate Ra measurements: 1) mass bias, 2) background, and 3) relative efficiencies of the detectors when measuring in MICS mode. Due to the absence of an established 226Ra/228Ra standard, we have used U reference material NBL-112A to monitor mass bias. Although Ball et. al., (in press) have shown that U does not serve as an adequate proxy for Th (and thus not likely for Ra either), measurements of rock standards TML and AThO are repeatedly in equilibrium within the uncertainty of the measurements (where total uncertainty includes propagation of the uncertainty in the 226Ra standard used for calibrating the 228Ra spike). For this application, U is an adequate proxy for Ra mass bias at the 1% uncertainly level. The more important issue is the background correction. Because of the extensive chemistry required to separate and purify Ra (typically fg/g level in volcanic rocks), we observe large

  1. 226Ra as a standard source for efficiency calibration of Ge(Li) detectors

    NASA Astrophysics Data System (ADS)

    Farouk, M. A.; Al-Soraya, A. M.

    1982-09-01

    The relative intensities of gamma-rays resulting from the decay of 226Ra in equilibrium with its short-lived daughters have been measured using two different high resolution Ge(Li) detectors. The accuracy of the measurements does not exceed 2.5%. The most intense components of gamma-rays from thin 226Ra are recommended for use as a calibration standard Ge(Li) detectors in the energy range from 186 keV to 3.050 MeV.

  2. Activity ratios of (234)U/(238)U and (226)Ra/(228)Ra for transport mechanisms of elevated uranium in alluvial aquifers of groundwater in south-western (SW) Punjab, India.

    PubMed

    Kumar, A; Karpe, R K; Rout, S; Gautam, Y P; Mishra, M K; Ravi, P M; Tripathi, R M

    2016-01-01

    The concentrations of total dissolved uranium (U), its isotopic composition ((234)U, (235)U, (238)U) and two long lived Ra isotopes ((226)Ra and (228)Ra) in alluvial aquifers of groundwater were determined to investigate the groundwater flow pattern in the south-western (SW) Punjab, India. Particular attention was given to the spatial variability of activity ratios (ARs) of (234)U/(238)U and (226)Ra/(228)Ra to predict the possible sources and supply process of U into the water from the solid phase. The measured groundwater (234)U/(238)U ARs were ∼1 or >1 in the shallow zone (depth < 30 m) with high U concentration and <1 in the deeper zone (depth > 30 m) with relatively low U concentration. The simultaneous elevated U concentration and (234)U/(238)U ARs in waters were possibly due to differences in imprints of rock-water interactions under hydrologic conditions. However, (234)U/(238)U ARs < 1 clearly indicate the lack of recharge from surface water to groundwater leading to (234)U deficit in groundwater. This deficit might be also attributed to alpha recoil processes under strong dissolution. Overall, the decreasing pattern of (234)U/(238)U ARs observed from SE to SW or NW ward clearly indicates a groundwater flow paths from SE to SW/NW. Similarly, (226)Ra/(238)U ARs < 1 for all water samples reflect that the precursor (238)U is fairly mobile relative to (226)Ra. This might be due to unusually high amount of (238)U in groundwaters and subsequently the different geochemistry of the two isotopes. On the other hand, (226)Ra/(228)Ra ARs in groundwaters varied widely and observed about 50-300 times higher than (238)U/(232)Th ARs in granitic rocks or soils. Such elevation in ARs might be attributed to different dissolution properties of their parents during water-rock interactions or lattice damage during decay or local enrichments of uranium in the aquifers. PMID:26555366

  3. Self-cleaning in an estuarine area formerly affected by 226Ra anthropogenic enhancements.

    PubMed

    Absi, A; Villa, M; Moreno, H P; Manjón, G; Periañez, R

    2004-08-15

    The estuary of the Odiel River has been affected by both direct discharges of phosphogypsum (radium enriched industrial waste) and dissolution and weathering of the exposed piles where this radium enriched waste was stored. In 1998 the waste management policy for industries changed. The direct discharges stopped and the new phosphogypsum piles were well protected against dissolution processes, avoiding any transference of radium into the environment. This work presents a study of the evolution with time (1999-2002) of the levels of 226Ra in river water and sediment samples with the new waste management policy. A liquid scintillation technique was used to measure the 226Ra activity concentration in sediment samples. A gas-proportional counter was also used to measure the 226Ra activity concentration in river water samples. The main conclusion is that a systematic and continuous decrease of the activity concentration of 226Ra with time in the Odiel River estuary is occurring. Thus, a possible self-cleaning in the estuary, once the direct waste discharges were avoided, can be inferred. PMID:15262166

  4. Determination of (226)Ra in produced water by liquid scintillation counting.

    PubMed

    Godoy, José Marcus; Vianna, Lucas M; Godoy, Maria Luiza D P; Almeida, Ana Cristina

    2016-08-01

    It is proposed a method for the determination of (226)Ra in offshore platform liquid effluent samples (produced water). The method is based on a two-phase liquid scintillation counting system and allows for the direct and simple determination of (226)Ra content. Samples with high barium content may also have high (226)Ra concentration. Therefore, the sample volume is based on the barium concentration and ranges from 10 mL to 100 mL. Our new method was tested using multiple real samples and was compared with the BaSO4 precipitation method. The results based on the LSC were 30% higher than the precipitation method, which is attributed to the self-absorption of alpha particles in the BaSO4 precipitate. The determination of both (226)Ra and (228)Ra in the liquid effluent of offshore oil platforms is mandatory in Brazil. Thus, a second method of accurately assessing (228)Ra content remains necessary. PMID:27116402

  5. [sup 226]Ra-[sup 230]Th disequilibrium in axial and off-axis mid-ocean ridge basalts

    SciTech Connect

    Volpe, A.M.; Goldstein, S.J. Los Alamos National Lab., NM )

    1993-03-01

    The authors describe [sup 226]Ra-[sup 230]Th disequilibrium in mid-ocean ridge basalt (MORB) glasses from the Juan de Fuca, Gorda, and East Pacific ridges. These first mass spectrometric measurements of [sup 226]Ra in MORB glasses at sub-picogram abundance levels confirm the large excesses over [sup 230]Th determined by radon-emanation techniques and alpha spectrometry. All off-axis MORB glasses have [sup 226]Ra-[sup 230]Th and [sup 234]U-[sup 238]U in secular equilibrium. This suggests that magmatic processes, not secondary post-eruption alteration, generate [sup 238]U-series disequilibrium in these MORB. Least evolved, N-MORB from axial valleys have ([sup 226]Ra/[sup 230]Th) between 2.2-2.3. Differentiated and enriched E-type MORB have consistently low ([sup 226]Ra/[sup 230]Th) ratios compared with N-MORB from the same ridge sections. Ra-Th fractionation may be less pronounced, or magma residence-transit periods may be long for differentiated MORB. Also, E-MORB may be generated by different melt extraction volumes and rates. Estimated [sup 226]Ra-[sup 230]Th ages for N-MORB agree with location on and off ridge segments, and with Th-U model ages. These preliminary results show that [sup 226]Ra-[sup 230]Th disequilibrium could be used to quantify volcanic episodicity at ocean ridges. 39 refs., 6 figs., 4 tabs.

  6. Fission of {sup 232}Th nuclei by linearly polarized photons

    SciTech Connect

    Khvastunov, V.M.; Denyak, V.V.; Evseev, I.G.; Zavada, L.M.; Kasilov, V.I.; Lapin, N.I.; Likhachev, V.P.; Pashchuk, S.A.; Sanin, V.M.; Shcherbak, S.F.

    1994-11-01

    The {Sigma}-asymmetry in the photofission of {sup 232}Th nuclei is measured using a beam of linearly polarized photons obtained by transmitting electrons through a silicon single crystal in conditions close to plane channeling. The measured {Sigma}-asymmetry values are compared with data from other experiments conducted using both polarized and unpolarized photon beams. No contributions from either electric quadrupole or magnetic dipole fission are observed within experimental accuracy. 14 refs., 7 figs.

  7. Fission of 232Th in a spallation neutron field

    NASA Astrophysics Data System (ADS)

    Yurevich, V. I.; Nikolaev, V. A.; Yakovlev, R. M.

    2016-03-01

    The spatial distributions of thorium fission reaction rate in a spallation neutron field of thick lead target bombarded by protons or deuterons with energy between 1.0 and 3.7 GeV were measured. Approximately a linear dependence of the thorium fission rate on the beam energy is observed. The mean fission cross section of 232Th <σ f > ≈ 123 mb and it does not depend on energy and type of the beam particles.

  8. 228Ra and 226Ra Profiles from the Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Lin, H.; Chung, Y.; Lin, C.

    2005-05-01

    We previously reported the distributions of 228Ra and 226Ra in the northern South China Sea (SCS) which showed that both nuclides in surface waters were much higher than those in the open oceans because the SCS was enclosed mostly by landmasses which are known as sources of these nuclides. Large temporal and spectial variations were also observed probably due to the monsoons and intrusion of the Kuroshio Current. During a recent cruise conducted in the northern SCS in February, 2004, three vertical 228Ra profiles were measured by gamma spectrometry on the Ra isotopes which were concentrated first by the MnO2-impregnated acrylic fiber and then acid-washed as sample solution for counting. The two deep water 228Ra profiles are remarkably similar, showing high values in the surface layer and fairly uniform at about 10 to 13 dpm/100L below 200m depth but with a clear increase toward the bottom due to input from the underlying sediments. The shallow water profile on the shelf shows higher 228Ra values due to both vertical and horizontal mixing of the shelf water with additional source from the shore zone. Additional 228Ra profiles measured on samples from earlier cruises show that the deep water values may differ significantly (up to 5 dpm/100L) at the same location in different seasons or cruises. The associated 226Ra profiles are also variable but quite comparable to those in the northwest Pacific in deep water. 226Ra activities in the shallow water (less than 1000m depth) are higher in the SCS than in the open oceans. The 228Ra/226Ra activity ratios vary mostly from about 0.3 to 0.5 in the deep water. These values are much higher than those in the open oceans which are generally less than 0.1.

  9. 18O and 226Ra in the Minjiang River estuary, China and their hydrological implications

    NASA Astrophysics Data System (ADS)

    Liu, Huatai; Guo, Zhanrong; Gao, Aiguo; Yuan, Xiaojie; Zhang, Bin

    2016-05-01

    In this work, the 2H, 18O and 226Ra values in groundwater and surface water in the Minjiang River estuary were investigated in the dry and wet seasons. The δ18O values in the dry season were always higher than those in the wet season in both groundwater and surface water because of the presence of evaporation in the water cycle process. During the dry season, the δ18O values in groundwater on the southern bank of the Minjiang River are much higher than those on the northern bank because evaporation is more intense in the farmland of the southern bank than in the urbanized northern bank. The δ18O values in the estuarine water exhibit a good positive correlation with salinity, with a coefficient of 0.96 (p = 0.05) in both seasons. The 226Ra activities in the estuarine water increase with increasing salinity because of desorption from riverine suspended particles. The 226Ra activity reaches a peak value at a salinity of 20.5. Based on a three-endmember model, the average proportions of the estuarine water are calculated to be 0.02 for groundwater, 0.39 for river water and 0.59 for seawater. From this mixing ratio, the groundwater discharge into the estuary is estimated to be 9.31 × 106 m3 d-1 in the wet season.

  10. Method to determine 226Ra in small sediment samples by ultralow background liquid scintillation.

    PubMed

    Sanchez-Cabeza, Joan-Albert; Kwong, Laval Liong Wee; Betti, Maria

    2010-08-15

    (210)Pb dating of sediment cores is a widely used tool to reconstruct ecosystem evolution and historical pollution during the last century. Although (226)Ra can be determined by gamma spectrometry, this method shows severe limitations which are, among others, sample size requirements and counting times. In this work, we propose a new strategy based on the analysis of (210)Pb through (210)Po in equilibrium by alpha spectrometry, followed by the determination of (226)Ra (base or supported (210)Pb) without any further chemical purification by liquid scintillation and with a higher sample throughput. Although gamma spectrometry might still be required to determine (137)Cs as an independent tracer, the effort can then be focused only on those sections dated around 1963, when maximum activities are expected. In this work, we optimized the counting conditions, calibrated the system for changing quenching, and described the new method to determine (226)Ra in small sediment samples, after (210)Po determination, allowing a more precise determination of excess (210)Pb ((210)Pb(ex)). The method was validated with reference materials IAEA-384, IAEA-385, and IAEA-313. PMID:20704374

  11. Concentration of 226Ra in rocks of the southern part of Lower Silesia (SW Poland).

    PubMed

    Przylibski, Tadeusz Andrzej

    2004-01-01

    The aim of the article is to present a preliminary description of rocks in the southern part of Lower Silesia and the Sudety Mountains in particular, with regard to 226Ra content. The research demonstrates that the average content of this isotope was 40.4 Bq/kg in the rocks of the southern part of Lower Silesia, and 41.7 Bq/kg in the rocks of the Sudetes. These values are slightly higher than the mean 226Ra content in the upper part of the Earth's crust, while the measured maximum content of this isotope (244 Bq/kg) is more than twice as high as the upper range of the values most frequently recorded in the upper part of the Earth's crust. The minimum values were lower than the detection limit, which was about 1 Bq/kg. These results reflect the mosaic-like geological structure of Lower Silesia, and particularly the Sudety Mountains, the occurrence of SiO2-rich igneous rocks and the products of their metamorphism, as well as numerous manifestations of uranium mineralisation or even deposital concentrations of this element. The rocks with the highest 226Ra contents include (in decreasing order): aplites, granites, gneisses and leucogranites, granite-gneisses, granodiorites and rhyolites, and, finally, mudstones. The lowest values of 226Ra content, on the other hand, were measured in sandstones, marls and conglomerates, and extremely low-in marbles and quartzites. The results show that background values of 226Ra content in the rocks of the southern part of Lower Silesia fall within a range from several to about 100 Bq/kg, which is the same as the range most frequently recorded in the upper part of the Earth's crust. Distribution of these values has log-normal character. The research demonstrates that the southern part of Lower Silesia, and the Sudetes in particular, may be marked by an increased radon potential. Particularly liable areas are: the Karkonosze granite massif, especially in its border zones, the Ladek-Snieznik and the Izera massifs, especially in their

  12. Tracking suspended particle transport via radium isotopes ((226)Ra and (228)Ra) through the Apalachicola-Chattahoochee-Flint River system.

    PubMed

    Peterson, Richard N; Burnett, William C; Opsahl, Stephen P; Santos, Isaac R; Misra, Sambuddha; Froelich, Philip N

    2013-02-01

    Suspended particles in rivers can carry metals, nutrients, and pollutants downstream which can become bioactive in estuaries and coastal marine waters. In river systems with multiple sources of both suspended particles and contamination sources, it is important to assess the hydrologic conditions under which contaminated particles can be delivered to downstream ecosystems. The Apalachicola-Chattahoochee-Flint (ACF) River system in the southeastern United States represents an ideal system to study these hydrologic impacts on particle transport through a heavily-impacted river (the Chattahoochee River) and one much less impacted by anthropogenic activities (the Flint River). We demonstrate here the utility of natural radioisotopes as tracers of suspended particles through the ACF system, where particles contaminated with arsenic (As) and antimony (Sb) have been shown to be contributed from coal-fired power plants along the Chattahoochee River, and have elevated concentrations in the surficial sediments of the Apalachicola Bay Delta. Radium isotopes ((228)Ra and (226)Ra) on suspended particles should vary throughout the different geologic provinces of this river system, allowing differentiation of the relative contributions of the Chattahoochee and Flint Rivers to the suspended load delivered to Lake Seminole, the Apalachicola River, and ultimately to Apalachicola Bay. We also use various geochemical proxies ((40)K, organic carbon, and calcium) to assess the relative composition of suspended particles (lithogenic, organic, and carbonate fractions, respectively) under a range of hydrologic conditions. During low (base) flow conditions, the Flint River contributed 70% of the suspended particle load to both the Apalachicola River and the bay, whereas the Chattahoochee River became the dominant source during higher discharge, contributing 80% of the suspended load to the Apalachicola River and 62% of the particles entering the estuary. Neither of these hydrologic

  13. Minimum speed limit for ocean ridge magmatism from 210Pb-226Ra-230Th disequilibria.

    PubMed

    Rubin, K H; van der Zander, I; Smith, M C; Bergmanis, E C

    2005-09-22

    Although 70 per cent of global crustal magmatism occurs at mid-ocean ridges-where the heat budget controls crustal structure, hydrothermal activity and a vibrant biosphere-the tempo of magmatic inputs in these regions remains poorly understood. Such timescales can be assessed, however, with natural radioactive-decay-chain nuclides, because chemical disruption to secular equilibrium systems initiates parent-daughter disequilibria, which re-equilibrate by the shorter half-life in a pair. Here we use 210Pb-226Ra-230Th radioactive disequilibria and other geochemical attributes in oceanic basalts less than 20 years old to infer that melts of the Earth's mantle can be transported, accumulated and erupted in a few decades. This implies that magmatic conditions can fluctuate rapidly at ridge volcanoes. 210Pb deficits of up to 15 per cent relative to 226Ra occur in normal mid-ocean ridge basalts, with the largest deficits in the most magnesium-rich lavas. The 22-year half-life of 210Pb requires very recent fractionation of these two uranium-series nuclides. Relationships between 210Pb-deficits, (226Ra/230Th) activity ratios and compatible trace-element ratios preclude crustal-magma differentiation or daughter-isotope degassing as the main causes for the signal. A mantle-melting model can simulate observed disequilibria but preservation requires a subsequent mechanism to transport melt rapidly. The likelihood of magmatic disequilibria occurring before melt enters shallow crustal magma bodies also limits differentiation and heat replenishment timescales to decades at the localities studied. PMID:16177787

  14. Comparison of radon fluxes with gamma-radiation exposure rates and soil /sup 226/Ra concentrations

    SciTech Connect

    Young, J.A.; Thomas, V.W.

    1984-04-01

    Radon fluxes and contact gamma-radiation-exposure rates were measured at the grid points of rectangular grids on three properties in Edgemont, South Dakota that were known to have deposits of residual radioactivity relatively near to the surface. The coefficient of determination, r/sup 2/, between the radon fluxes and the contact gamma-radiation-exposure rates varied from 0.89 to 0.31 for the three properties. The property having the highest fluxes and residual radioactivity of relatively uniform depth showed the highest correlation between fluxes and exposure rates, and the property having residual radioactivity that varied considerably in depth showed the lowest. Correlations between fluxes and /sup 226/Ra concentrations measured in boreholes that varied in depth from 60 to 195 cm were lower than those between fluxes and exposure rates, indicating that exposure rates are better than /sup 226/Ra measurements for detecting elevated radon fluxes from near-surface deposits. Measurements made on one property at two different times indicated that if the average flux were determined from a large number (40) of measurements at one time, the average flux at a later time could be estimated from a few measurements using the assumption that the change in the flux at individual locations will be equal to the change in the average flux. Flux measurements around two buildings showing elevated indoor radon-daughter concentrations, but around which no residual radioactivity had been discovered by /sup 226/Ra and gamma-radiation measurements, provided no clear indication of the presence of such material, possibly because none was present.

  15. Determination of 226Ra and 224Ra in drinking waters by liquid scintillation counting.

    PubMed

    Manjón, G; Vioque, I; Moreno, H; García-Tenorio, R; García-León, M

    1997-04-01

    A method for the determination of Ra-isotopes in water samples has been developed. Ra is coprecipitated with Ba as sulphate. The precipitate is then dissolved with EDTA and counted with a liquid scintillation system after mixing with a scintillation cocktail. The study of the temporal evolution of the separated activity gives the isotopic composition of the sample, i.e. the 224Ra and 226Ra contribution to the total activity. The method has been applied to some Spanish drinking waters. PMID:9106993

  16. Potential sources affecting the activity concentrations of 238U, 235U, 232Th and some decay products in lettuce and wheat samples.

    PubMed

    Jeambrun, M; Pourcelot, L; Mercat, C; Boulet, B; Pelt, E; Chabaux, F; Cagnat, X; Gauthier-Lafaye, F

    2012-11-01

    The activity concentrations of radionuclides within the uranium and thorium series were determined in wheat and lettuce at five sites in France, and in their respective potential sources: crop soils of wheat and crop soils and irrigation waters of lettuce. These data were used to calculate concentration ratios and to enrich the database supported by the technical report series N°472 of the IAEA (2010). For wheat and lettuce, the activity concentrations were in the same range for all radionuclides studied, except for (210)Pb, which had higher activity concentrations in wheat, ranging between 1.3 and 11 Bq kg(−1) (fresh weight) as compared to 0.4 and 0.7 Bq kg(−1) (fresh weight) for lettuce. For wheat, the range of activity concentrations (mBq kg(−1); fresh weight) decreased as (210)Pb > (226)Ra (56–1511) ≈ (228)Ra (86–769) > (228)Th (19–176) ≈ (238)U (11–169) ≈ (234)U (12–150) ≈ (230)Th (9.08–197.18) ≈ (232)Th (8.61–121.45) > (235)U (0.53–7.9). For lettuce, it decreased as (228)Ra (<320–1221) > (210)Pb (409–746) > (226)Ra (30–599) ≈ (228)Th (<29–347) > (238)U (8–120) ≈ (234)U (8–121) ≈ (230)Th (5.21–134.63) ≈ (232)Th (5.25–156.99) > (235)U (0.35–5.63). The species differences may reflect different plant physiologies. Through the study of activity ratios of wheat and lettuce in relation with those of the various radionuclide sources it has been possible to highlight the contribution of the main sources of natural radionuclides. Indeed, irrigation water when the uranium concentration is enhanced (>30 mBq L(−1)) contributed significantly to the activity concentration of uranium in lettuces. Concerning the high activity concentrations of (210)Pb, it could be explained by atmospheric particle deposition. The effect of soil particles resuspension and their adhesion to the plant surface seemed to be important in some cases. The soil-to-plant transfer factors were calculated for lettuce and wheat. The values were

  17. Disequilibrium between [sup 226]Ra and supported [sup 210]Pb in a sediment core from a shallow Florida lake

    SciTech Connect

    Brenner, M.; Peplov, A.J.; Schelske, C.L. )

    1994-07-01

    [sup 210]Pb dating can be used to assign ages in lake sediment cores, calculate rates of sediment accumulation, and determine the timing of recent changes in lake-watershed ecosystems. We used low-background gamma counting to measure [sup 226]Ra and total [sup 210]Pb activity in a core from Lake Rowell, Florida. [sup 226]Ra activity was high and strongly variable throughout the core, even exceeding total [sup 210]Pb activity in recently deposited sediments. We traced one source of Ra-rich sediments to the only inflow, Alligator Creek, where stream-bottom deposits display disequilibrium between [sup 226]Ra and supported [sup 210]Pb. High and variable [sup 226]Ra activity in the Lake Rowell profile argues for direct estimates of in situ Ra in lake sediment cores from disturbed watersheds that have Ra-bearing bedrock. Isotopic disequilibrium between [sup 226]Ra and supported [sup 210]Pb makes it difficult to distinguish between supported and unsupported [sup 210]Pb activity throughout the Lake Rowell core and would require special assumptions and nonconventional dating models to establish age-depth relationships. 78 refs., 3 figs., 1 tab.

  18. Comparative Analysis Of {sup 226}Ra Soil-To-Plant Transfer In Cabbage Grown In Various Regions

    SciTech Connect

    Madruga, M. J.; Carvalho, F. P.; Silva, L.; Gouveia, J.

    2008-08-07

    The transfer of {sup 226}Ra from soil to cabbage was compared amongst regions, namely the surroundings of Urgeirica uranium milling tailings (GE), regions with past uranium mining activities (GN1), and regions with no uranium mining activities and no uranium deposits (GN2). Results show a slight increase of the concentration ratio values at low radium concentration in soils. Statistical analysis of the mean {sup 226}Ra activity concentrations in soil and cabbage for the three regions was carried out. The comparison of {sup 226}Ra activity concentrations in soils indicated no difference (p>0.05), between GE and GN2 and significant differences (p<0.05) between GE and GN1 and between GN1 and GN2. Similar statistical results were obtained for {sup 226}Ra activity concentrations in cabbage from the same regions. It was concluded that radium Concentration Ratio (CR) for cabbage grown in the region of the main uranium milling site (GE) is of the same order of magnitude of CR in cabagge grown in background regions (GN2). However, {sup 226}Ra CR was higher in cabagge from the region with past uranium mining activities (GN1)

  19. Symmetric and asymmetric modes of {sup 232}Th photofission at intermediate energies

    SciTech Connect

    Demekhina, N. A.; Karapetyan, G. S.

    2010-01-15

    Yields of fragments originating from {sup 232}Th photofission were measured at bremsstrahlungphoton endpoint energies of 50 and 3500 MeV. Charge and mass distributions of fission fragments were analyzed. On the basis of the model of multimode fission, symmetric and asymmetric channels are singled out in {sup 232}Th photofission at intermediate energies. This decomposition made it possible to estimate the contributions of various fission components and the fissility of {sup 232}Th.

  20. Laser trapping of 225Ra and 226Ra with repumping by room-temperature blackbody radiation.

    PubMed

    Guest, J R; Scielzo, N D; Ahmad, I; Bailey, K; Greene, J P; Holt, R J; Lu, Z-T; O'Connor, T P; Potterveld, D H

    2007-03-01

    We have demonstrated Zeeman slowing and capture of neutral 225Ra and 226Ra atoms in a magneto-optical trap. The intercombination transition 1S0-->3P1 is the only quasicycling transition in radium and was used for laser-cooling and trapping. Repumping along the 3D1-->1P1 transition extended the lifetime of the trap from milliseconds to seconds. Room-temperature blackbody radiation was demonstrated to provide repumping from the metastable 3P0 level. We measured the isotope shift and hyperfine splittings on the 3D1-->1P1 transition with the laser-cooled atoms, and set a limit on the lifetime of the 3D1 level based on the measured blackbody repumping rate. Laser-cooled and trapped radium is an attractive system for studying fundamental symmetries. PMID:17359153

  1. /sup 232/Th(. gamma. ,f) and (. gamma. ,n) reactions between 5 and 10 MeV

    SciTech Connect

    Findlay, D.J.S.; Edwards, G.; Hawkes, N.P.; Sene, M.R.

    1985-01-15

    Cross sections for the photofission /sup 232/Th(..gamma..,f) and photoproduction /sup 232/Th(..gamma..,n) reactions have been measured with a photon energy resolution of 130, 200, 390 keV for data points taken in intervals of 100, 200, and 400 keV. (AIP)

  2. Measurement of 224Ra and 226Ra activities in natural waters using a radon-in-air monitor

    USGS Publications Warehouse

    Kim, G.; Burnett, W.C.; Dulaiova, H.; Swarzenski, P.W.; Moore, W.S.

    2001-01-01

    We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed air-loop connected to a commercial radon-in-air monitor. The monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semiconductor detector. Count data are collected in energy-specific windows, which eliminate interference and maintain very low backgrounds. Radium-224 is measured immediately after sampling via 220Rn (216Po), and 226Ra is measured via 222Rn (218Po) after a few days of ingrowth of 222Rn. This technique is rapid, simple, and accurate for measurements of low-level 224Ra and 226Ra activities without requiring any wet chemistry. Rapid measurements of short-lived 222Rn and 224Ra, along with long-lived 226Ra, may thus be made in natural waters using a single portable system for environmental monitoring of radioactivity as well as tracing of various geochemical and geophysical processes. The technique could be especially useful for the on-site rapid determination of 224Ra which has recently been found to occur at elevated activities in some groundwater wells.

  3. Microbial release of 226Ra2+ from (Ba,Ra)SO4 sludges from uranium mine wastes.

    PubMed Central

    Fedorak, P M; Westlake, D W; Anders, C; Kratochvil, B; Motkosky, N; Anderson, W B; Huck, P M

    1986-01-01

    226Ra2+ is removed from uranium mine effluents by coprecipitation with BaSO4. (Ba,Ra)SO4 sludge samples from two Canadian mine sites were found to contain active heterotrophic populations of aerobic, anaerobic, denitrifying, and sulfate-reducing bacteria. Under laboratory conditions, sulfate reduction occurred in batch cultures when carbon sources such as acetate, glucose, glycollate, lactate, or pyruvate were added to samples of (Ba,Ra)SO4 sludge. No external sources of nitrogen or phosphate were required for this activity. Further studies with lactate supplementation showed that once the soluble SO4(2-) in the overlying water was depleted, Ba2+ and 226Ra2+ were dissolved from the (Ba,Ra)SO4 sludge, with the concurrent production of S2-. Levels of dissolved 226Ra2+ reached approximately 400 Bq/liter after 10 weeks of incubation. Results suggest that the ultimate disposal of these sludges must maintain conditions to minimize the activity of the indigenous sulfate-reducing bacteria to ensure that unacceptably high levels of 226Ra2+ are not released to the environment. PMID:3752993

  4. Extreme 210Pb-226Ra Disequilibria Observed in arc Lavas: Implications for the Time Scales of Magma Degassing

    NASA Astrophysics Data System (ADS)

    Turner, S.; Black, S.

    2003-12-01

    We have undertaken α -counting measurements of 210Pb activity in 39 arc lavas previously analysed by TIMS for U-Th-Ra and, more recently, U-Pa disequilibria from the Lesser Antilles, Tonga, Vanuatu, Philippines, Marianas, Sunda, Kamchatka and the Aleutians. The lavas were erupted between 1953 and 1999 and show extreme variation in 210Pb -226Ra disequilibria with age corrected (210Pb /226Ra) activity ratios ranging from 0.36 to 3.14. In detail, the majority (25) of the lavas analysed preserve 210Pb deficits with 17 having (210Pb /226Ra) < 0.9 and 7 (210Pb /226Ra) < 0.8 whilst 5 are below (210Pb /226Ra) = 0.6. Of the 14 lavas that have 210Pb excess, 6 have (210Pb /226Ra) > 1.2. Whereas 210Pb deficits are found across the compositional spectrum of lavas analysed (silica = 47-65 percent), (210Pb /226Ra) appears to increase with increasing silica in those lavas that have 210Pb excesses. The 210Pb deficits are most readily interpreted in terms of protracted magma degassing and the numerical model of Gauthier and Condomines 1999 (EPSL 172: 111-126) suggests that the typical duration of degassing is on the order of 10's of years but may reach 45 years in the case of the largest 210Pb deficits at Yasur in Vanuatu, Mt Mayon in the Philippines, Avachinsky in Kamchatka and Spurr, Redoubt and Shishaldin in the Aleutians. These estimates for the duration of degassing represent minimum time scales since they assume 100 percent efficient degassing of 222Rn and no magma replenishment during that period. Therefore, it appears that the majority of arc magmas undergo efficient and protracted degassing for decades prior to eruption. By contrast, there is no simple model for explaining the 210Pb excesses. Mass balance calculations indicate that plagioclase accumulation cannot account for the observed excesses. Instead, we suggest that inefficient gas release and/or sublimation of 210Pb produced by decay from 222Rn during gaseous transport through the magma may be responsible for the

  5. 226Ra-230Th Disequilibria in Magmas from Llaima and Lonquimay Volcanoes, Chile: On the Roles and Rates of Subvolcanic Magmatic Processes.

    NASA Astrophysics Data System (ADS)

    Reubi, O.; Cooper, L. B.; Dungan, M. A.; Bourdon, B.

    2014-12-01

    226Ra excesses in mafic arc magmas are generally attributed to recent (< 8 kyr) addition of slab-fluid to the mantle wedge and/or mantle melting. Preservation of 226Ra-230Th disequilibria from such sources requires short crustal residence times (<< 8 kyr) for these magmas. The correlation between 226Ra excesses and 10Be/Be previously observed for magmas from the Chilean Southern Volcanic Zone (SVZ) contributed to the view that recent slab-fluid additions causes 226Ra excesses in arc magmas1. Our extensive dataset for Llaima and Lonquimay volcanoes (SVZ) shows variations in (226Ra/230Th) for each volcano, and in some cases within single eruptions. These variations span almost the entire SVZ range and question the pertinence of mantle-derived 226Ra-230Th disequilibria models. Llaima and Lonquimay volcanoes differ in terms of their petrology and magmatic evolution. Llaima magmas (51 to 55 wt% SiO2) are predominantly crystal-rich and carry conspicuous evidence for magma mixing and AFC processes. 238U and 231Pa excesses and incompatible trace element ratios are correlated and this can be accounted for by up to 20% assimilation of basement plutonic rocks2. Crustal contamination had a secondary influence on 226Ra-230Th disequilibria. Magmas with the highest AFC contribution have 226Ra-230Th close to equilibrium, implying that (226Ra-230Th) are mostly affected by either differentiation on time scales of ~8 kyr, or more likely, mixing with mush bodies several kyr old. Lonquimay magmas (52 to 64 wt% SiO2) are almost aphyric. Their evolution was controlled by fractional crystallization with limited crustal contamination. (226Ra-230Th) range from moderate 226Ra excesses to small deficits, and are negatively correlated with Ba/Th and MgO. These observations are difficult to reconcile with only slab-fluid addition and mantle melting. We posit that this (226Ra-230Th) range results from diffusive Ra-exchange between young recharge melts and an old crystal mush. A similar process

  6. Precise Determination of the Intensity of 226Ra Alpha Decay to the 186 keV Excited State

    SciTech Connect

    S.P. LaMont; R.J. Gehrke; S.E. Glover; R.H. Filby

    2001-04-01

    There is a significant discrepancy in the reported values for the emission probability of the 186 keV gamma-ray resulting from the alpha decay of 226 Ra to 186 keV excited state of 222 Rn. Published values fall in the range of 3.28 to 3.59 gamma-rays per 100 alpha-decays. An interesting observation is that the lower value, 3.28, is based on measuring the 186 keV gamma-ray intensity relative to the 226 Ra alpha-branch to the 186 keV level. The higher values, which are close to 3.59, are based on measuring the gamma-ray intensity from mass standards of 226 Ra that are traceable to the mass standards prepared by HÓNIGSCHMID in the early 1930''s. This discrepancy was resolved in this work by carefully measuring the 226 Ra alpha-branch intensities, then applying the theoretical E2 multipolarity internal conversion coefficient of 0.692±0.007 to calculate the 186 keV gamma-ray emission probability. The measured value for the alpha branch to the 186 keV excited state was (6.16±0.03)%, which gives a 186 keV gamma-ray emission probability of (3.64±0.04)%. This value is in excellent agreement with the most recently reported 186 keV gamma-ray emission probabilities determined using 226 Ra mass standards.

  7. Low impact of exposure to environmentally relevant doses of 226Ra in Atlantic cod (Gadus morhua) embryonic cells.

    PubMed

    Olsvik, Pål A; Berntssen, Marc H G; Hylland, Ketil; Eriksen, Dag Ø; Holen, Elisabeth

    2012-07-01

    The aim of this study was to investigate whether (226)Ra, a radionuclide present in produced water from oil platforms in the North Sea and other offshore drilling areas, could affect vulnerable early life stages of Atlantic cod (Gadus morhua). Blastula-stage embryonic cells (EC) from fertilized eggs of Atlantic cod were isolated and exposed to environmental relevant concentrations of (226)Ra and transcription of selected genes quantified. The results showed a weak, but significant up-regulation of GPx3 and HSP70 transcripts after 48 h of exposure to 2.11 Bq/L. In EC exposed to three (226)Ra concentrations (2.11, 23 and 117 Bq/L) for 12 h, metallothionein, HSP90AA, thioredoxin and caspase 8 were significantly up-regulated in cells exposed to 117 Bq/L, whereas thioredoxin was also significantly up-regulated in EC exposed to 23 Bq/L. When EC were exposed to the same (226)Ra concentrations for 48 h, only heme oxygenase was significantly up-regulated in the 23 Bq/L exposure group. The results suggest that environmentally relevant activities of (226)Ra may induce oxidative stress and apoptosis in fish ECs. Exposure of Atlantic cod EC to Cd, selected as a model toxicant, supported the ability of EC around blastula stage to respond to toxicants by altered transcription. Due to dilution, environmentally relevant concentrations of radionuclides present in produced water would be expected to pose a minor threat to early life stages of fish. PMID:22388182

  8. Distribution of (226)Ra-(210)Pb-(210)Po in marine biota and surface sediments of the Red Sea, Sudan.

    PubMed

    Sirelkhatim, D A; Sam, A K; Hassona, R K

    2008-12-01

    Activity concentration levels and ratios of (226)Ra, (210)Pb and (210)Po are presented in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (Flamingo bay) of PortSudan harbour, Sudan. The analyses were performed adopting alpha-spectrometry, liquid scintillation and Cerenkov counting techniques. Surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported from different coastal areas around the globe. There is surface enrichment of (210)Pb and (210)Po with respect to their progenitor (226)Ra as it is evident from the activity ratios of (210)Pb/(226)Ra (3.03+/-1.79) and (210)Po/(226)Ra (2.23+/-1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2Bq/kg and 21.9Bq/kg dry weight, respectively. Similarly, the highest concentration of (210)Po was met in Favites at 38.7Bq/kg followed by brown algae, Cystoseria sp., at 32.6Bq/kg. There is no variation seen among algal species for (210)Pb uptake, however, converse to radium and polonium, Favites (coral) was found to contain the minimum concentration of lead (3.88Bq/kg). In most species there is preferential accumulation of polonium over its parent radium as indicated by (210)Po:(226)Ra activity ratio with Cystoseria (brown algae) showing the highest value at 8.81. On the other hand, (210)Po:(210)Pb activity concentration ratio revealed that coral species Favites (9.97) and the brown algae Sargassum (1.85) have a greater tendency to accumulate (210)Po over (210)Pb, while in the rest of species; this ratio is less than unity. PMID:18774629

  9. Leaching of 226Ra from U mill tailings by sulfate-reducing bacteria.

    PubMed

    Landa, E R; Miller, C L; Updegraff, D M

    1986-10-01

    Relatively insoluble sulfate precipitates appear to be a major host for Ra in sulfuric acid-treated, U mill tailings. The dissolution of such precipitates by natural processes, such as metabolism by sulfate-reducing bacteria (SRB), creates the potential for release of Ra to contacting waters. Significant leaching of Ra by SRB was achieved in the laboratory during the anaerobic incubation (1 to 119 days) of U mill tailings with pure cultures of Desulfovibrio desulfuricans and mixed cultures containing SRB isolated from the tailings, all grown on a lactate medium at room temperature. While the maximum 226Ra concentration reached in a sterile media control was 0.44 Bq/L (12 pCi/L), that in the SRB systems was 61 Bq/L (1640 pCi/L) or about 20% of the total Ra inventory in the original tailings sample. The leaching of Ra in SRB systems was accompanied by a decrease in soluble sulfate concentration, an increase in total sulfide concentration, and an increase in the number of SRB. The observed leaching effect does not appear to be due to the action of microbial chelates or to binding to cell walls. Potential implications of these findings to the management of U mill tailings and other radioactive wastes are discussed. PMID:3759464

  10. Leaching of /sup 226/Ra from U mill tailings by sulfate-reducing bacteria

    SciTech Connect

    Landa, E.R.; Miller, C.L.; Updegraff, D.M.

    1986-10-01

    Relatively insoluble sulfate precipitates appear to be a major host for Ra in sulfuric acid-treated, U mill tailings. The dissolution of such precipitates by natural processes, such as metabolism by sulfate-reducing bacteria (SRB), creates the potential for release of Ra to contacting waters. Significant leaching of Ra by SRB was achieved in the laboratory during the anaerobic incubation (1 to 119 days) of U mill tailings with pure cultures of Desulfovibrio desulfuricans and mixed cultures containing SRB isolated from the tailings, all grown on a lactate medium at room temperature. While the maximum /sup 226/Ra concentration reached in a sterile media control was 0.44 Bq/L (12 pCi/L), that in the SRB systems was 61 Bq/L (1640 pCi/L) or about 20% of the total Ra inventory in the original tailings sample. The leaching of Ra in SRB systems was accompanied by a decrease in soluble sulfate concentration, an increase in total sulfide concentration, and an increase in the number of SRB. The observed leaching effect does not appear to be due to the action of microbial chelates or to binding to cell walls. Potential implications of these findings to the management of U mill tailings and other radioactive wastes are discussed.

  11. Thermoluminescence and excess 226Ra decay dating of late Quaternary fluvial sands, East Alligator River, Australia

    NASA Astrophysics Data System (ADS)

    Murray, Andrew; Wohl, Ellen; East, Jon

    1992-01-01

    Thermoluminescence (TL) dating was applied to seven samples of siliceous fluvial sands from the East Alligator River of Northern Australia, giving ages ranging from modern to 6000 yr B.P. Two methods of estimating the equivalent dose (ED), total bleach and regenerative, were applied to the 90- to 125-μm quartz fraction of the samples in order to determine the reliability and internal consistency of the technique. High-resolution γ and α spectroscopy were used to measure radionuclide contents; these measurements revealed an excess 226Ra activity compared with 230Th. This excess decreased with depth, and was used directly to derive mean sedimentation rates, and thus sediment ages. Both this method and one 14C date confirmed the validity of the TL values, which increased systematically with depth and were consistent with site stratigraphy. TL was of limited use in the dating of these late Holocene deposits because of age uncertainties of 500 to 1600 yr, resulting from a significant residual ED. This residual probably resulted from incomplete bleaching during reworking upstream of the sampling site. For Pleistocene deposits, the residual ED will be less significant because of higher total EDs, and TL dates will be correspondingly more accurate.

  12. Field analyses of (238)U and (226)Ra in two uranium mill tailings piles from Niger using portable HPGe detector.

    PubMed

    Déjeant, Adrien; Bourva, Ludovic; Sia, Radia; Galoisy, Laurence; Calas, Georges; Phrommavanh, Vannapha; Descostes, Michael

    2014-11-01

    The radioactivities of (238)U and (226)Ra in mill tailings from the U mines of COMINAK and SOMAÏR in Niger were measured and quantified using a portable High-Purity Germanium (HPGe) detector. The (238)U and (226)Ra activities were measured under field conditions on drilling cores with 600s measurements and without any sample preparation. Field results were compared with those obtained by Inductive Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and emanometry techniques. This comparison indicates that gamma-ray absorption by such geological samples does not cause significant deviations. This work shows the feasibility of using portable HPGe detector in the field as a preliminary method to observe variations of radionuclides concentration with the aim of identifying samples of interest. The HPGe is particularly useful for samples with strong secular disequilibrium such as mill tailings. PMID:25036918

  13. (The determination of sup 222 Rn flux from soils based on sup 210 Pb and sup 226 Ra disequilibrium)

    SciTech Connect

    Turekian, K.K.

    1991-01-01

    The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.

  14. Non-destructive determination of 224Ra, 226Ra and 228Ra concentrations in drinking water by gamma spectroscopy.

    PubMed

    Parekh, Pravin; Haines, Douglas; Bari, Abdul; Torres, Miguel

    2003-11-01

    The U.S. Environmental Protection Agency mandates that drinking water showing gross alpha-activity greater than 0.19 Bq L(-1) should be analyzed for radium, a known human carcinogen. The recommended testing methods are intricate and laborious. The method reported in this paper is a direct, non-destructive gamma-spectroscopic method for the determination of 224Ra, 226Ra, and 228Ra, the three radium isotopes of environmental concern in drinking water. Large-volume Marinelli beakers (4.1-L capacity), especially designed for measuring radioactive gases, in conjunction with a low-background, high-efficiency (131%) germanium detector were used in this work. It was first established that radon, the gaseous decay product of radium, and its progeny are quantitatively retained in this Marinelli beaker. The 224Ra, 226Ra, and 228Ra activity concentrations are determined from the equilibrium activities of their progeny: 212Pb, 214Pb (214Bi), and 228Ac; and the gamma-lines used in the analysis are 238.6, 351.9 (and 609.2), and 911.2 keV, respectively. The 224Ra activity is determined from the first 1,000-min measurement performed after expulsion of radon from the sample. The 226Ra activity is determined from the second, 2,400-min measurement, made 3 to 5 d later, and the 228Ra activity is determined from either the first or the second measurement, depending on its concentration level. The method's minimum detectable activities are 0.017 Bq L(-1), 0.020 Bq L(-1), and 0.027 Bq L(-1) for 224Ra, 226Ra, and 228Ra, respectively, when measured under radioactive equilibrium. These limits are well within the National Primary Drinking Water Regulations required limit of 0.037 Bq L(-1) for 226Ra and for 228Ra. The precision and accuracy of the method, evaluated using the U.S. Environmental Protection Agency and the Environmental Resource Associates' quality control samples, were found to be within acceptable limits. PMID:14571995

  15. U-isotopes and (226)Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas.

    PubMed

    Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

    2016-07-01

    Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ((238)U, (235)U and (234)U) and (226)Ra by alpha spectrometry were determined. The activity concentration of (238)U presented a large variation from around 1.1 to 65 mBq L(-1). Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The (234)U/(238)U activity ratios were higher than unity for all samples (1.1-3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. (226)Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10(2) mBq L(-1)); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed (226)Ra/(234)U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). (226)Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest (234)U/(238)U activity ratios, probably due to fast uniform bulk mineral dissolution

  16. Photofissility of [sup 232]Th measured with tagged photons from 250 to 1200 MeV

    SciTech Connect

    Bianchi, N.; Deppman, A.; De Sanctis, E.; Fantoni, A.; Levi Sandri, P.; Lucherini, V.; Muccifora, V.; Polli, E.; Reolon, A.R.; Rossi, P.; Iljinov, A.S.; Mebel, M.V.; Arruda-Neto, J.D.T. ); Anghinolfi, M.; Corvisiero, P.; Gervino, G.; Mazzaschi, L.; Mokeev, V.; Ricco, G.; Ripani, M.; Sanzone, M.; Taiuti, M.; Zucchiatti, A. ); Bergere, R.; Carlos, P.; Garganne, P.; Lepretre, A. )

    1993-10-01

    The photofission cross section of [sup 232]Th was measured in the energy range 250--1200 MeV using a monochromatic tagged photon beam and a parallel-plate avalanche detector. The [sup 232]Th nuclear photofissility was obtained by measuring simultaneously and in the same energy range the photofission cross section of [sup 238]U and assuming a photofissility equal to one for [sup 238]U. It was found that, contrary to the case for heavier actinides, the [sup 232]Th photofissility value does not saturate up to 1200 MeV. Rather, it lies between 0.6 and 0.8, and shows a weak energy dependence: it increases by about 15% over an interval of 1 GeV. A comparison of these experimental findings with the predictions of an intranuclear-cascade Monte Carlo calculation is given.

  17. MSFIA-LOV system for (226)Ra isolation and pre-concentration from water samples previous radiometric detection.

    PubMed

    Rodríguez, Rogelio; Borràs, Antoni; Leal, Luz; Cerdà, Víctor; Ferrer, Laura

    2016-03-10

    An automatic system based on multisyringe flow injection analysis (MSFIA) and lab-on-valve (LOV) flow techniques for separation and pre-concentration of (226)Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO2 and the BaSO4 co-precipitation, achieving more selectivity especially in water samples with low radium levels. Radium is adsorbed on MnO2 deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO2 to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO4. The (226)Ra can be directly detected in off-line mode using a low background proportional counter (LBPC) or through a liquid scintillation counter (LSC), after performing an on-line coprecipitate dissolution. Thus, the versatility of the proposed system allows the selection of the radiometric detection technique depending on the detector availability or the required response efficiency (sample number vs. response time and limit of detection). The MSFIA-LOV system improves the precision (1.7% RSD), and the extraction frequency (up to 3 h(-1)). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The (226)Ra minimum detectable activities (LSC: 0.004 Bq L(-1); LBPC: 0.02 Bq L(-1)) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC. PMID:26893088

  18. Non-destructive determination of uranium, thorium and 40K in tobacco and their implication on radiation dose levels to the human body.

    PubMed

    Landsberger, S; Lara, R; Landsberger, S G

    2015-11-01

    The naturally occurring radionuclides of (235)U, (238)U and (232)Th and their daughter products are a potential major source of anthropogenic radiation to tobacco smokers. Often overlooked is the presence of (40)K in tobacco and its implication to radiation dose accumulation in the human body. In this study, these three radiation sources have been determined in four typical US cigarettes using neutron activation analysis (NAA). The NAA reactions of (238)U(n,γ)(239)U, (232)Th(n,γ)(233)Th and (41)K(n,γ)(42)K were used to determine (235)U, (238)U and (232)Th and (40)K, respectively. The activity of (238)U can easily be determined by epithermal NAA of the (238)U(n,γ)(239)U reaction, and the activity of (235, 234)U can easily be deduced. Using isotopic ratios, the activity due to (40)K was found by the determined concentrations of (41)K (also by epithermal neutrons) in the bulk material. Each gram of total potassium yields 30 Bq of (40)K. The annual effective dose for smokers using 20 cigarettes per day was calculate to be 14.6, 137 and 9 μSv y(-1) for (238,235,) (234)U, (232)Th and (40)K, respectively. These values are significantly lower that the dose received from (210)Po except for (232)Th. PMID:25944955

  19. Seasonal changes in submarine groundwater discharge to coastal salt ponds estimated using 226Ra and 228Ra as tracers

    USGS Publications Warehouse

    Hougham, A.L.; Moran, S.B.; Masterson, J.P.; Kelly, R.P.

    2008-01-01

    Submarine groundwater discharge (SGD) to coastal southern Rhode Island was estimated from measurements of the naturally-occurring radioisotopes 226Ra (t1/2 = 1600??y) and 228Ra (t1/2 = 5.75??y). Surface water and porewater samples were collected quarterly in Winnapaug, Quonochontaug, Ninigret, Green Hill, and Pt. Judith-Potter Ponds, as well as nearly monthly in the surface water of Rhode Island Sound, from January 2002 to August 2003; additional porewater samples were collected in August 2005. Surface water activities ranged from 12-83??dpm 100??L- 1 (60??dpm = 1??Bq) and 21-256??dpm 100??L- 1 for 226Ra and 228Ra, respectively. Porewater 226Ra activities ranged from 16-736??dpm 100??L- 1 (2002-2003) and 95-815??dpm 100??L- 1 (2005), while porewater 228Ra activities ranged from 23-1265??dpm 100??L- 1. Combining these data with a simple box model provided average 226Ra-based submarine groundwater fluxes ranging from 11-159??L m- 2 d- 1 and average 228Ra-derived fluxes of 15-259??L m- 2 d- 1. Seasonal changes in Ra-derived SGD were apparent in all ponds as well as between ponds, with SGD values of 30-472??L m- 2 d- 1 (Winnapaug Pond), 6-20??L m- 2 d- 1 (Quonochontaug Pond), 36-273??L m- 2 d- 1 (Ninigret Pond), 29-76??L m- 2 d- 1 (Green Hill Pond), and 19-83??L m- 2 d- 1 (Pt. Judith-Potter Pond). These Ra-derived fluxes are up to two orders of magnitude higher than results predicted by a numerical model of groundwater flow, estimates of aquifer recharge for the study period, and values published in previous Ra-based SGD studies in Rhode Island. This disparity may result from differences in the type of flow (recirculated seawater versus fresh groundwater) determined using each technique, as well as variability in porewater Ra activity. ?? 2007 Elsevier B.V. All rights reserved.

  20. Soil features and indoor radon concentration prediction: radon in soil gas, pedology, permeability and 226Ra content.

    PubMed

    Lara, E; Rocha, Z; Santos, T O; Rios, F J; Oliveira, A H

    2015-11-01

    This work aims at relating some physicochemical features of soils and their use as a tool for prediction of indoor radon concentrations of the Metropolitan Region of Belo Horizonte (RMBH), Minas Gerais, Brazil. The measurements of soil gas radon concentrations were performed by using an AlphaGUARD monitor. The (226)Ra content analysis was performed by gamma spectrometry (high pure germanium) and permeabilities were performed by using the RADON-JOK permeameter. The GEORP indicator and soil radon index (RI) were also calculated. Approximately 53 % of the Perferric Red Latosols measurement site could be classified as 'high risk' (Swedish criteria). The Litholic Neosols presented the lowest radon concentration mean in soil gas. The Perferric Red Latosols presented significantly high radon concentration mean in soil gas (60.6 ± 8.7 kBq m(-3)), high indoor radon concentration, high RI, (226)Ra content and GEORP. The preliminary results may indicate an influence of iron formations present very close to the Perferric Red Latosols in the retention of uranium minerals. PMID:25920786

  1. Measuring the radium quartet (228Ra, 226Ra, 224Ra, 223Ra) in seawater samples using gamma spectrometry.

    PubMed

    van Beek, P; Souhaut, M; Reyss, J-L

    2010-07-01

    Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While 228Ra and 226Ra are usually measured using gamma spectrometry, short-lived Ra isotopes (224Ra and 223Ra) are usually measured using a Radium Delayed Coincidence Counter (RaDeCC). Here we show that the four radium isotopes can be analyzed using gamma spectrometry. We report 226Ra, 228Ra, 224Ra, 223Ra activities measured using low-background gamma spectrometry in standard samples, in water samples collected in the vicinity of our laboratory (La Palme and Vaccarès lagoons, France) but also in seawater samples collected in the plume of the Amazon river, off French Guyana (AMANDES project). The 223Ra and 224Ra activities determined in these samples using gamma spectrometry were compared to the activities determined using RaDeCC. Activities determined using the two techniques are in good agreement. Uncertainties associated with the 224Ra activities are similar for the two techniques. RaDeCC is more sensitive for the detection of low 223Ra activities. Gamma spectrometry thus constitutes an alternate method for the determination of short-lived Ra isotopes. PMID:20106569

  2. {sup 226}Ra and {sup 231}Pa systematics of axial MORB, crustal residence ages, and magma chamber characteristics at 9--10{degree}N East Pacific Rise

    SciTech Connect

    Goldstein, S.J.; Murrell, M.T.; Perfit, M.R.; Batiza, R.; Fornari, D.J.

    1994-06-01

    Mass spectrometric measurements of {sup 30}Th-22{sup 226}Ra and {sup 235}-U{sup 231}Pa disequilibria for axial basalts are used to determine crustal residence ages for MORB magma and investigate the temporal and spatial characteristics of axial magma chambers (AMC) at 9--10{degrees}N East Pacific Rise (EPR). Relative crustal residence ages can be calculated from variations in {sup 226}Ra/{sup 230}Th and {sup 231}Pa/{sup 235}U activity ratios for axial lavas, if (1) mantle sources and melting are uniform, and mantle transfer times are constant or rapid for axial N-MORB, and (2) {sup 231}Pa/{sup 235}U and {sup 226}Ra/{sup 230}Th in the melt are unaffected by shallow level fractional crystallization. Uniform Th, Sr, and Nd isotopic systematics and incompatible element ratios for N-MORB along the 9--10{degrees}N segment indicate that mantle sources and transfer times are similar. In addition, estimated bulk solid/melt partition coefficients for U, Th, and Pa are small, hence effects of fractional crystallization on {sup 231}Pa/{sup 235}U ratios for the melt are expected to be negligible. However, fractional crystallization of plagioclase in the AMC would lower {sup 226}Ra/{sup 230}Th ratios in the melt and produce a positive bias in {sup 226}Ra crustal residence ages for fractionated lavas.

  3. The ability of Helianthus annuus L. and Brassica juncea to uptake and translocate natural uranium and 226Ra under different milieu conditions.

    PubMed

    Vera Tomé, F; Blanco Rodríguez, P; Lozano, J C

    2009-01-01

    Seedlings of Helianthus annuus L. (HA) and Brassica juncea (BJ) were used to test the effect of the pH, the presence of phosphates, and the addition of ethylene-diamine-tetraacetic acid (EDTA) or citrate on the uptake and the translocation of uranium isotopes ((238)U, (235)U, and (234)U) and (226)Ra. The results indicated that the presence of phosphates generally reduces the uptake and transfer of uranium from the roots to the shoots of HA. In the case of BJ, while phosphate enhanced the retention of uranium by roots, the translocation was poorer. Likewise, for (226)Ra, the best translocation was in the absence of phosphates for both species. The addition of citrate increased the translocation of uranium for both species, but had no clear effect on the transfer of (226)Ra. The effect of EDTA was much more moderate both for uranium and for (226)Ra, and for both plant species. Only noticeable was a slightly better uptake of (226)Ra by BJ at neutral pH, although the translocation was lower. PMID:18848715

  4. High resolution studies of photofission of /sup 232/Th and /sup 238/U

    SciTech Connect

    Zhang, H.X.; Lancman, H.

    1985-01-15

    Photofission cross sections have been determined in several photon energy intervals with a photon energy resolution approx.200 eV. The structure observed at 6.31 MeV in /sup 232/Th is interpreted as a reflection of class II compound states in this nucleus.

  5. High resolution studies of photofission of /sup 232/Th and /sup 238/U

    SciTech Connect

    Zhang, H.X.; Lancman, H.

    1984-01-01

    Photofission cross sections have been determined in several photon energy intervals with a photon energy resolution approx.200 eV. The structure observed at 6.31 MeV in /sup 232/Th is interpreted as a reflection of class II compound states in this nucleus. 4 refs., 3 figs., 1 tab.

  6. Daily intakes of 232Th and 238U in Japanese males.

    PubMed

    Shiraishi, K; Igarashi, Y; Takaku, Y; Masuda, K; Yoshimizu, K; Nishimura, Y; Hongo, S; Yamaguchi, H

    1992-08-01

    Diet samples were collected by a duplicate portion method from 31 locations in Japan and were analyzed by inductively coupled plasma mass spectrometry. Average daily intakes per adult male were estimated at 1.7 mBq for 232Th and 8.8 mBq for 238U. PMID:1399617

  7. Dating ivory by determination of 14C, 90Sr and 228/232Th.

    PubMed

    Schmied, Stefanie A K; Brunnermeier, Matthias J; Schupfner, Robert; Wolfbeis, Otto S

    2012-09-10

    A method is described to determine the time of death of elephants. This is accomplished by analysis of the radionuclides 14C, 90Sr and 228/232Th in known samples of ivory, and in samples of unknown age. The reliability of this method is considerably increased by multi nuclide analysis. PMID:22717552

  8. Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

    DOE PAGESBeta

    Kayzar, Theresa M.; Williams, Ross W.

    2015-09-26

    The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th-234U, 226Ra-238U, 231Pa-235U, and 227Ac-235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra-238U and 227Ac-235U chronometers and provide information about nuclide migration during uranium processing.

  9. An experimental analysis of the contribution of 224Ra and 226Ra and progeny to the gross alpha-particle activity of water samples.

    PubMed

    Arndt, Michael F; West, Lynn E

    2008-05-01

    The gross alpha-particle activity of water samples analyzed by EPA Method 900.0 is investigated as a function of residue mass and geometry, time between sample collection and analysis, and time between sample preparation and analysis for samples containing 224Ra, 212Pb, and 226Ra. It is shown that the gross alpha-particle activity due to 224Ra and its progeny can be up to 10 times the 224Ra activity at collection time and that due to 212Pb progeny can be up to 3 times the 212Pb activity at collection time. In samples with roughly equal activities of 224Ra and 226Ra analyzed soon after collection, it is shown that the gross alpha-particle activity is approximately constant with time because the decay of 224Ra and its progeny is offset by the ingrowth of 226Ra progeny. PMID:18403967

  10. An improved method for the simultaneous determination of /sup 224/Ra, /sup 226/Ra and /sup 228/Ra in water, soils and sediments

    SciTech Connect

    Lucas, H.F.

    1987-01-01

    The naturally occurring concentrations of radium (/sup 226/Ra and /sup 228/Ra) in public and private water supplies have been studied for many years. Both general surveys ad local studies have established the geographical regions where well waters exceed 3 pCi/L (1-17). In general, the /sup 226/Ra was determined by the emanation method, while the /sup 228/Ra was determined from the beta activity of the /sup 228/Ac daughter. In a recent review (18) of the methods used ''a number of approved analytic methods can bear improvement, especially the method for 228Ra.'' The purpose of the work described here was to develop an improved method for the simultaneous determination of /sup 226/Ra and /sup 228/Ra. 22 refs., 3 tabs.

  11. Flow rates and reaction rates in the Galapagos Rise spreading center hydrothermal system as inferred from 228Ra/226Ra in vesicomyid clam shells

    PubMed Central

    Turekian, Karl K.; Cochran, J. Kirk

    1986-01-01

    The 228Ra/226Ra ratios in a previously dated vesicomyid clam shell were used to determine that seawater was in contact with mid-oceanic-ridge basalt glass for 22-45 years prior to arrival to the surface at 350°C at the Galapagos Rise Spreading Center. The minimum rate of reaction for the 45-year sojourn time, based on a water/rock ratio of 2.8 derived from 226Ra concentrations, is 8 g of basalt altered per kg of seawater per year. PMID:16593746

  12. A computer program integrating a multichannel analyzer with gamma analysis for the estimation of sup 226 Ra concentration in soil samples

    SciTech Connect

    Wilson, J. E.

    1992-08-01

    A new hardware/software system has been implemented using the existing three-regions-of-interest method for determining the concentration of {sup 226}Ra in soil samples for the Pollutant Assessment Group of the Oak Ridge National Laboratory. Consisting of a personal computer containing a multichannel analyzer, the system utilizes a new program combining the multichannel analyzer with a program analyzing gamma-radiation spectra for {sup 226}Ra concentrations. This program uses a menu interface to minimize and simplify the tasks of system operation.

  13. A computer program integrating a multichannel analyzer with gamma analysis for the estimation of {sup 226} Ra concentration in soil samples

    SciTech Connect

    Wilson, J. E.

    1992-08-01

    A new hardware/software system has been implemented using the existing three-regions-of-interest method for determining the concentration of {sup 226}Ra in soil samples for the Pollutant Assessment Group of the Oak Ridge National Laboratory. Consisting of a personal computer containing a multichannel analyzer, the system utilizes a new program combining the multichannel analyzer with a program analyzing gamma-radiation spectra for {sup 226}Ra concentrations. This program uses a menu interface to minimize and simplify the tasks of system operation.

  14. A measurement of the thermal neutron capture cross section of /sup 232/Th

    SciTech Connect

    Jones, R.T.; Merritt, J.S.; Okazaki, A.

    1986-06-01

    The thermal neutron capture cross section of /sup 232/Th has been measured relative to that of /sup 197/Au. Foils of gold, thorium metal, and thoria were irradiated together in the NRU reactor thermal column. The /sup 198/Au activity was assayed in a 4..pi gamma.. ionization chamber, which had been previously calibrated with samples of /sup 198/Au standardized by the 4..pi beta..-..gamma.. coincidence method. Protactinium-233 sources were also standardized by this method. Comparison of these sources with the irradiated thorium, by means of a Ge(Li) spectrometer, enabled the /sup 233/Pa activity in the thorium-bearing foils to be determined. Taking the 2200 m/s capture cross section of /sup 197/Au to be 98.8 b, that of /sup 232/Th is found to be 7.33+.0.06b. The uncertainty is at the 95% confidence level and includes an estimate of the systematic uncertainties.

  15. Fission Product Decay Heat Calculations for Neutron Fission of 232Th

    NASA Astrophysics Data System (ADS)

    Son, P. N.; Hai, N. X.

    2016-06-01

    Precise information on the decay heat from fission products following times after a fission reaction is necessary for safety designs and operations of nuclear-power reactors, fuel storage, transport flasks, and for spent fuel management and processing. In this study, the timing distributions of fission products' concentrations and their integrated decay heat as function of time following a fast neutron fission reaction of 232Th were exactly calculated by the numerical method with using the DHP code.

  16. Ultra Sensitive Neutron Activation Measurements of {sup 232}Th in Copper

    SciTech Connect

    Clemenza, M.; Previtali, E.; Borio di Tigliole, A.; Salvini, A.

    2011-04-27

    Copper, thanks to its low content in radioactive contaminations, is a material widely used for shielding, holders and other objects close to the sensitive parts of the detectors in many experiments in rare event physics. This implies that tools able to reach sensitivity of the order of <10{sup -12} gram of contaminants per gram of copper are of crucial importance. A methodology based in Neutron Activation Analysis (NAA) has been developed to obtain an extremely high sensitivity in the analysis of {sup 232}Th in copper samples. A detection limit of 5x10{sup -13} g {sup 232}Th/g Cu has been achieved through the irradiation of 200 g of copper sample which subsequently was radio-chemically concentrated using nitric acid and then actinide resin from Eichrom Inc. Several elutions were performed with various inorganic acids to concentrate the {sup 232}Th activation product ({sup 233}Pa) from the copper matrix and to also eliminate the radioactive background induced by the neutron bombardment to reach higher sensitivity.

  17. Tracing pre-eruptive magma degassing using ( 210Pb/ 226Ra) disequilibria in the volcanic deposits of the 1980-1986 eruption of Mount St. Helens

    NASA Astrophysics Data System (ADS)

    Berlo, Kim; Turner, Simon; Blundy, Jon; Black, Stuart; Hawkesworth, Chris

    2006-09-01

    Disequilibria between 210Pb and 226Ra can be used to trace magma degassing, because the intermediate nuclides, particularly 222Rn, are volatile. Products of the 1980-1986 eruptions of Mount St. Helens have been analysed for ( 210Pb/ 226Ra). Both excesses and deficits of 210Pb are encountered suggesting rapid gas transfer. The time scale of diffuse, non-eruptive gas escape prior to 1980 as documented by 210Pb deficits is on the order of a decade using the model developed by Gauthier and Condomines (Earth Planet. Sci. Lett. 172 (1999) 111-126) for a non-renewed magma chamber and efficient Rn removal. The time required to build-up 210Pb excess is much shorter (months) as can be observed from steady increases of ( 210Pb/ 226Ra) with time during 1980-1982. The formation of 210Pb excess requires both rapid gas transport through the magma and periodic blocking of gas escape routes. Superposed on this time trend is the natural variability of ( 210Pb/ 226Ra) in a single eruption caused by tapping magma from various depths. The two time scales of gas transport, to create both 210Pb deficits and 210Pb excesses, cannot be reconciled in a single event. Rather 210Pb deficits are associated with pre-eruptive diffuse degassing, while 210Pb excesses document the more vigorous degassing associated with eruption and recharge of the system.

  18. (226) RA AND (228) RA ACTIVITIES ASSOCIATED WITH AGRICULTURAL DRAINAGE PONDS AND WETLAND PONDS IN THE KANKAKEE WATERSHED, IL-IN, USA

    EPA Science Inventory

    Background radioactivity is elevated in many agricultural drainage ponds and also constructed wetland ponds in the Kankakee watershed. During 1995-1999, gross-a and -B activities were measured up to 455 and 1650 mBq L-1, respectively. 226Ra and 228Ra averaged 139 and 192 mBq L-01...

  19. Dissolved and Particulate 230Th - 232Th systematics in the Central Equatorial Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Lopez, G. I.; Marcantonio, F.

    2013-12-01

    To complement our work in the eastern Equatorial Pacific, we have measured total and dissolved 230Th and 232Th in the central Equatorial Pacific at two sites, one at 8°N and the other at the equator (ML1208-03CTD; 00° 13.166' S, 155° 57.668' W and ML1208-12CTD; 8° 19.989' N, 159° 18.000' W). The two seawater casts were collected in May 2012 during an NSF-funded "Line Islands" cruise to test for the extent of advection or diffusion of dissolved 230Th from the oligotrophic North Pacific gyre (low particle flux) to the more productive equatorial region (high particle flux). Our thorium results are similar to previous data published for the western and central North Pacific Ocean. Dissolved 230Th concentrations range from 1.1 fg/kg at 100 m to 30.8 fg/kg at 4400 m, while dissolved 232Th concentrations span from 8.1 pg/kg at 900 m to 19.7 pg/kg at 4400 m. The pattern of the dissolved 230Th profile at 8°N is essentially linear from the surface to 2000 m. From 2000 m to 3000 m, the dissolved 230Th concentrations are constant, and then from 3000 m to the bottom, the profile is linear again. At the same site, the particulate fraction of the total seawater 230Th increases exponentially from about 0% at the surface to 38% at 4400 m. From 0 to 3000 m at 8°N, dissolved 232Th concentrations display a relatively constant pattern (variability of about 20%). From 3000 m to 4400 m, dissolved 232Th contents are more variable, but generally increase toward greater depths. The proportion of 232Th in the particulate fraction of the total seawater sample increases exponentially with depth to a value of 58% in the bottommost sample. We will present additional data from the equator and assess the particulate dynamics that control the distribution of thorium isotopes in central equatorial Pacific seawater.

  20. Timescales of degassing and crystallization implied by 210Po- 210Pb- 226Ra disequilibria for andesitic lavas erupted from Arenal volcano

    NASA Astrophysics Data System (ADS)

    Reagan, Mark K.; Tepley, Frank J.; Gill, James B.; Wortel, Matthew; Garrison, Jennifer

    2006-09-01

    Disequilibrium between 210Po, 210Pb, and 226Ra was measured on whole rocks and plagioclase mineral separates erupted between 1968 and 2003 from Arenal volcano with a goal of monitoring the volatile fluxing and crystallization in the decades and years leading up to eruption. Degassing during the eruption was found to remove nearly all 210Po from Arenal lavas, which appears to be true of lava eruptions in general. Most of Arenal's lavas have ( 210Pb)/( 226Ra) ratios within 20% of equilibrium, indicating that most of the magmas involved in this eruption did not have strong, persistent fluxes of 222Rn in or out of the system during the decades leading to eruption. This is consistent with a time-frame of differentiation from basalt to basaltic andesite exceeding a century. Lava erupted in 1971 had ( 210Pb) in excess of ( 226Ra) by as much as a factor of 2. These lavas were the first to mark the change in geochemical trends that were likely caused by the arrival of a new magma at the surface at Arenal [Ryder, C.H., Gill, J.B., Tepley III, F., Ramos, F., Reagan, M., this issue. Closed to open system differentiation at Arenal Volcano (1968-2003). Journal of Volcanology and Geothermal Research.], suggesting that the 210Pb excess was related to the first appearance of this magma. The high ( 210Pb)/( 226Ra) ratio in this lava apparently reflects Rn-degassing from large volumes of underlying magma and/or extraction of Rn from conduit-area rocks or fluids due to deformation and heating. Plagioclase mineral separates had 210Po- 210Pb- 226Ra disequilibrium patterns suggesting a growth period stretching over a period of more than 50 years up to the time of eruption.

  1. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    NASA Astrophysics Data System (ADS)

    Sabatier, P.; Reyss, J.-L.; Hall-Spencer, J. M.; Colin, C.; Frank, N.; Tisnérat-Laborde, N.; Bordier, L.; Douville, E.

    2012-03-01

    Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr-1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr-1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr-1, with high uncertainty (~1 polyp every two to three years). We are less certain of this 210Pb growth rate estimate which is within the lowermost ranges of previous growth

  2. Exploring quasifission characteristics for +232Th34S forming 266Sg

    NASA Astrophysics Data System (ADS)

    Prasad, E.; Wakhle, A.; Hinde, D. J.; Williams, E.; Dasgupta, M.; Evers, M.; Luong, D. H.; Mohanto, G.; Simenel, C.; Vo-Phuoc, K.

    2016-02-01

    Background: Fission fragments from heavy ion collisions with actinide nuclei show mass-asymmetric and mass-symmetric components. The relative probabilities of these two components vary rapidly with beam energy with respect to the capture barrier, indicating a strong dependence on the alignment of the deformed nucleus with the partner in the collisions. Purpose: To study the characteristics of the mass-asymmetric quasifission component by reproducing the experimental mass-angle distributions to investigate mass evolution and sticking times. Methods: Fission fragment mass-angle distributions were measured for the +232Th34S reaction. Simulations to match the measurements were made by using a classical phenomenological approach. Mass ratio distributions and angular distributions of the mass-asymmetric quasifission component were simultaneously fit to constrain the free parameters used in the simulation. Results: The mass-asymmetric quasifission component—predominantly originating from tip (axial) collisions with the prolate deformed 232Th —is found to be peaked near A =200 at all energies and center-of-mass angles. A Monte Carlo model using the standard mass equilibration time constant of 5.2 ×10-21 s predicts more symmetric mass splits. Three different hypotheses assuming (i) a mass halt at A =200 , (ii) a slower mass equilibration time, or (iii) a Fermi-type mass drift function reproduced the main experimental features. Conclusions: In tip collisions for the +232Th34S reaction, mass-asymmetric fission with A ˜200 is the dominant outcome. The average sticking time is found to be ˜7 ×10-21 s, independent of the scenario used for mass evolution.

  3. Rapid determination of 226Ra and uranium isotopes in solid samples by fusion with lithium metaborate and alpha spectrometry.

    PubMed

    Bojanowski, R; Radecki, Z; Piekoś, R

    2002-07-01

    A simple and rapid method has been developed to determine 226Ra in rocks, soils, and sediments. Samples are decomposed by fusion with lithium metaborate and the melt is dissolved in a solution containing sulfates and citric acid. During the dissolution, a fine suspension of mixed barium and radium sulfates is formed. The microcrystals are collected on a membrane filter (pore size 0.1 microm) and analysed in an alpha spectrometer. Application of a 133Ba tracer enables us to assess the loss of the analyte, which only rarely exceeds 10%. All analytical operations, beginning from sample decomposition to source preparation for alpha spectrometry, can be accomplished within 1 or 2 h. With uranium determination, the filtrate is spiked with a 232U tracer and passed through a column loaded with a Dowex AG (1 x 4) anion-exchange resin in the sulfate form. Interfering elements are eluted with dilute sulfuric acid followed by concentrated hydrochloric acid. Uranium is eluted with water, electrodeposited on silver discs, and analysed in the alpha spectrometer. The method was tested on reference soil and sediment materials and was found to be accurate within the estimated uncertainties. PMID:12920318

  4. Laser-trapping of {sup 225}Ra and {sup 226}Ra with repumping by room-temperature blackbody radiation.

    SciTech Connect

    Guest, J. R.; Scielzo, N. D.; Ahmad, I.; Bailey, K.; Greene, J. P.; Holt, R. J.; Lu, Z.-T.; O'Connor, T. P.; Potterveld, D. H.; Physics; Enrico Fermi Inst.; Univ. of Chicago

    2007-02-27

    We have demonstrated Zeeman slowing and capture of neutral {sup 225}Ra and {sup 226}Ra atoms in a magneto-optical trap. The intercombination transition {sup 1}S{sub 0} {yields} {sup 3}P{sub 1} is the only quasicycling transition in radium and was used for laser-cooling and trapping. Repumping along the {sup 3}D{sub 1} {yields} {sup 1}P{sub 1} transition extended the lifetime of the trap from milliseconds to seconds. Room-temperature blackbody radiation was demonstrated to provide repumping from the metastable {sup 3}P{sub 0} level. We measured the isotope shift and hyperfine splittings on the {sup 3}D{sub 1} {yields} {sup 1}P{sub 1} transition with the laser-cooled atoms, and set a limit on the lifetime of the {sup 3}D{sub 1} level based on the measured blackbody repumping rate. Laser-cooled and trapped radium is an attractive system for studying fundamental symmetries.

  5. Intermediate structure in the photofission cross section of /sup 232/Th

    SciTech Connect

    Zhang, H.X.; Yeh, T.R.; Lancman, H.

    1984-07-02

    Intermediate structure has been observed in the photofission cross section of /sup 232/Th measured with a photon energy resolution <500 eV. The gamma rays, variable in energy, were obtained from the (p,..gamma..) reaction on several nuclei. The average spacing of the observed photofission resonances at an excitation energy of 6.16 MeV is 1.6 +- 0.4 keV. The average areas of the resonances are compared with theoretical expectations for a double-humped and a triple-humped barrier.

  6. High resolution photofission measurements in /sup 238/U and /sup 232/Th

    SciTech Connect

    Lancman, H.

    1984-01-01

    Photofission measurements have been continued at subbarrier energies. Strong intermediate resonances have been observed at an excitation energy of 6.14 MeV in /sup 232/Th. The photons were obtained from the E/sub p/ = 1020 keV resonance in /sup 34/S(P,..gamma..). Their average energy resolution was approx. 200 eV. Various properties of the observed intermediate structure were compared with theoretical predictions based on a double-humped and triple-humped barrier.

  7. Fission fragment angular distributions for the system 19F+232Th

    NASA Astrophysics Data System (ADS)

    Kailas, S.; Navin, A.; Chatterjee, A.; Singh, P.; Choudhury, R. K.; Saxena, A.; Nadkarni, D. M.; Kapoor, S. S.; Ramamurthy, V. S.; Nayak, B. K.; Suryanarayana, S. V.

    1991-03-01

    The fission fragment angular distributions for the system 19F+232Th have been measured at several bombarding energies between 94 and 108 MeV. Even though the anisotropy values measured in the present work are considerably smaller than the ones reported by Zhang et al. for the same system at similar energies, they are still anomalous when compared with the predictions of the standard saddle-point statistical model and fit into the systematics of entrance-channel dependence of fission anisotropies reported by us earlier.

  8. [The determination of {sup 222}Rn flux from soils based on {sup 210}Pb and {sup 226}Ra disequilibrium]. Progress report

    SciTech Connect

    Turekian, K.K.

    1991-12-31

    The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.

  9. Discovery of low-lying E1 and M1 strengths in {sup 232}Th

    SciTech Connect

    Adekola, A. S.; Hammond, S. L.; Hill, A.; Karwowski, H. J.; Angell, C. T.; Howell, C. R.; Kwan, E.; Kelley, J. H.

    2011-03-15

    Properties of low-energy dipole states in {sup 232}Th have been investigated with the nuclear resonance fluorescence technique. The present work used monoenergetic {gamma}-ray beams at energies of 2-4 MeV from the high-intensity {gamma}-ray source at Triangle Universities Nuclear Laboratory. Over 40 transitions corresponding to deexcitation to the ground state and first excited state were observed for the first time. Excitation energies, integrated cross sections, decay widths, branching ratios, and transition strengths for those states in {sup 232}Th were determined and compared with quasiparticle random-phase-approximation calculations. A large number of E1 transitions were observed for the first time in actinide nuclei with summed strength of 3.28(69)x10{sup -3} e{sup 2} fm{sup 2}. The observed summed M1 strength of 4.26(63){mu}{sub N}{sup 2} is in good agreement with the other actinides and with the systematics of the scissors mode in deformed rare-earth nuclei.

  10. Analysis of the cross section for {sup 232}Th photofission in the subbarrier energy region

    SciTech Connect

    Blokhin, A. I. Soldatov, A. S.

    2009-06-15

    A theoretical analysis of the most detailed experimental data on the subbarrier fission of {sup 232}Th is performed. The energy dependences of the components of the cross sections for photofission through specific channels characterized by the quantum numbers J{sup {pi}K} are obtained on the basis of previously measured total photofission cross sections and angular distributions of fission fragments. A theoretical analysis of the subbarrier photofission of {sup 232}Th is performed on the basis of the results obtained for these components. This analysis relies on the one-dimensional fission model within which one assumes a three-humped structure of the fission barrier and introduces damping in the second and third wells by including an imaginary part in the potential used. Values are selected for the parameters of the fission barriers and are compared with similar data from other studies. It is shown that the energy dependences of the photofission cross sections in question can be described adequately.

  11. Unusual 232Th and 238U contamination on some road surfaces in Taoyuan, Taiwan.

    PubMed

    Chang, W P; Nabyvanets, Y B; Jen, M H

    2001-06-01

    At least eight bustling streets or approximately 3-5% of all the road surface of civilian utility in the downtown area of Taoyuan City, Taiwan, were inadvertently found to contain unusual levels of radioactivity during a routine environmental radiation surveillance in mid-1994. Crushed rock debris and coarse sands separated from the asphalt pavement were identified to be the source of excessive radioactivity. By employing gamma spectrometry, we have measured 232Th activity (via 228Ac) and mU activity (via 214Bi) in some of the samples to be up to about 4,000 and 1,000 Bq kg(-1), respectively. The dose rate on the road surface reached about 1.3 microSv h(-1), as compared with the background level of 0.08 microSv h(-1) in much of Taiwan. This unusual radioactivity was due to accidental mixing of road construction materials with materials enriched 232Th and 238U. PMID:11388731

  12. Studies of positron electron pair production in {sup 238}U + {sup 232}Th

    SciTech Connect

    Ahmad, I.; Back, B.B.; Betts, R.R.

    1995-08-01

    Following the non-observation of sharp sum-energy lines in our earlier {sup 238}U + {sup 181}Ta measurements, it was decided to pursue measurements of the {sup 238}U + {sup 232}Th system which, in the previously published work, showed the most striking evidence for near-equal-energy back-to-back pairs leading to sharp sum-energy lines. Following the refurbishing of the APEX silicon arrays and extensive tests of the rotating target wheel assembly, a major positron run took place in November 1994. Rolled 1-mg/cm{sub 2} {sup 232}Th targets were bombarded with 5.95-MeV/u {sup 238}U. The target rotation allowed up to 2 pnA of beam to be used without serious deterioration of the targets. Over 300,000 pairs were accumulated, representing an order-of-magnitude improvement in statistics over the previously published results. Preliminary analysis shows no evidence for the sharp lines at a cross section level orders of magnitude below those previously reported. The analysis of these data is currently being completed in preparation for publication.

  13. Mapping the spatial distribution and activity of (226)Ra at legacy sites through Machine Learning interpretation of gamma-ray spectrometry data.

    PubMed

    Varley, Adam; Tyler, Andrew; Smith, Leslie; Dale, Paul; Davies, Mike

    2016-03-01

    Radium ((226)Ra) contamination derived from military, industrial, and pharmaceutical products can be found at a number of historical sites across the world posing a risk to human health. The analysis of spectral data derived using gamma-ray spectrometry can offer a powerful tool to rapidly estimate and map the activity, depth, and lateral distribution of (226)Ra contamination covering an extensive area. Subsequently, reliable risk assessments can be developed for individual sites in a fraction of the timeframe compared to traditional labour-intensive sampling techniques: for example soil coring. However, local heterogeneity of the natural background, statistical counting uncertainty, and non-linear source response are confounding problems associated with gamma-ray spectral analysis. This is particularly challenging, when attempting to deal with enhanced concentrations of a naturally occurring radionuclide such as (226)Ra. As a result, conventional surveys tend to attribute the highest activities to the largest total signal received by a detector (Gross counts): an assumption that tends to neglect higher activities at depth. To overcome these limitations, a methodology was developed making use of Monte Carlo simulations, Principal Component Analysis and Machine Learning based algorithms to derive depth and activity estimates for (226)Ra contamination. The approach was applied on spectra taken using two gamma-ray detectors (Lanthanum Bromide and Sodium Iodide), with the aim of identifying an optimised combination of detector and spectral processing routine. It was confirmed that, through a combination of Neural Networks and Lanthanum Bromide, the most accurate depth and activity estimates could be found. The advantage of the method was demonstrated by mapping depth and activity estimates at a case study site in Scotland. There the method identified significantly higher activity (<3 Bq g(-1)) occurring at depth (>0.4m), that conventional gross counting algorithms

  14. The cumulative effect of three decades of phosphogypsum amendments in reclaimed marsh soils from SW Spain: (226)Ra, (238)U and Cd contents in soils and tomato fruit.

    PubMed

    Abril, José-María; García-Tenorio, Rafael; Enamorado, Santiago M; Hurtado, M Dolores; Andreu, Luis; Delgado, Antonio

    2008-09-15

    Phosphogypsum (PG), a by-product of the phosphate fertiliser industries, has been applied as soil amendment to reduce Na saturation in soils, as in the reclaimed marsh area from SW Spain, where available PG has a typical fingerprint of 710+/-40 Bq kg(-1) of (226)Ra, 165+/-15 Bq kg(-1) of (238)U and 2.8+/-0.4 mg kg(-1) of Cd. This work was focussed on the cumulative effects of PG amendments on the enrichment of these pollutants in cultivated soils and plants (Lycopersicum esculentum Mill L.) from the area studied, where PG has been applied since 1978 at recommended rates of 20-25 Mg ha(-1) every 2-3 years. A field experiment was conducted over three years to compare activity concentrations of (226)Ra ((214)Pb) and (238)U ((234)Th) in non-reclaimed soils, reclaimed soils with no additional PG application, and reclaimed soils with two additional PG applications. A non-significant effect of two PG amendments (in three years) was observed when compared with non-amended reclaimed plots. Nevertheless, a significant (p<0.05) enrichment of (226)Ra was observed in the surface horizon (0-30 cm) of reclaimed plots relative to deeper horizons and also when compared with the surface horizon of non-reclaimed soil (p<0.05), thereby revealing the cumulative effect of three decades of PG applications. Furthermore, the effect of a continuous application of PG was studied by analysing soils and tomato fruits from six commercial farms with different cumulative rates of PG applied. Cadmium concentrations in tomatoes, which were one order of magnitude higher than those found in tomatoes from other areas in South Spain, were positively correlated (r = 0.917) with (226)Ra-concentration in soils, which can be considered an accurate index of the cumulative PG rate of each farm. PMID:18602676

  15. Assessment of annual effective dose from 238U and 226Ra due to consumption of foodstuffs by inhabitants of Tehran city, Iran.

    PubMed

    Hosseini, T; Fathivand, A A; Abbasisiar, F; Karimi, M; Barati, H

    2006-01-01

    The concentrations of (238)U and (226)Ra were determined in different foodstuffs purchased from markets in Tehran. Determinations of the radionuclides have been carried out using alpha spectrometry technique, on samples of egg, lentil, potato, rice, soya, spinach, tea and wheat. Average concentrations of natural radionuclides and foodstuff consumption rate were used to assess annual intake and based on intake values, the annual effective ingestion dose has been estimated for Tehran city residents. The measurement results show that soya has the maximum concentration of (238)U equal to 15.6 +/- 2.6 mBq kg(-1) and tea has the maximum concentration of (226)Ra equal to 1153.3 +/- 265.3 mBq kg(-1). Besides, the maximum annual effective dose from (238)U and (226)Ra were assessed to be 2.88 x 10(-2) +/- 7.20 x 10(-3) and 2.15 +/- 0.54 muSv, respectively, from wheat samples. PMID:16547147

  16. Biological availability of (238)U, (234)U and (226)Ra for wild berries and meadow grasses in natural ecosystems of Belarus.

    PubMed

    Sokolik, G A; Ovsiannikova, S V; Voinikava, K V; Ivanova, T G; Papenia, M V

    2014-01-01

    This work is devoted to investigation of behavior of (234)U, (238)U and (226)Ra by determining the soil to plant transfer under different natural conditions such as forest or swamped areas and meadow lands with different soil types. The paper summarizes the data on investigation of uranium and radium uptake by wild berries and natural meadow grasses in the typical conditions of Belarus. Parameters characterizing the biological availability of (234)U, (238)U and (226)Ra for bilberry (Vaccinium myrtillus), lingonberry (Vaccinium viti-idaea), blueberry (Vaccinium iliginosum) and cranberry (Vaccinium oxycoccus palustris) as well as for widely occurring mixed meadow vegetation, which belongs to the sedge-grass or grass-sedge associations and forbs, have been established. In the sites under investigation, the deposition levels of (238+239+240)Pu were less than 0.37 kBq m(-2) and (137)Cs deposition ranged between less than 0.37 and 37 kBq m(-2). It was found that activity concentrations of radionuclides in berries varied in the ranges of 0.037-0.11 for (234)U, 0.036-0.10 for (238)U and 0.11-0.43 Bq kg(-1) for (226)Ra, but in the mixed meadow grasses they were 0.32-4.4, 0.24-3.9 and 0.14-6.9 Bq kg(-1) accordingly. The (234)U/(238)U activity ratios were 1.02 ± 0.01 for wild berries, 1.20 ± 0.09 for underground meadow grasses and 1.02 ± 0.02 for proper soils. The concentration ratios (CRs, dry weight basis) of (234)U and (238)U for mixed meadow grasses were 0.036-0.42 and 0.041-0.46 respectively. The correspondent geometric means (GM) were 0.13 and 0.15 with geometric standard deviations (GSD) of 2.4. The CRs of (226)Ra for meadow grasses were 0.031-1.0 with GM 0.20 and GSD 2.6. The CRs of (234)U, (238)U and (226)Ra for wild berries ranged within 0.0018-0.008 (GM is 0.0034, GSD is 1.8), 0.0018-0.008 (GM is 0.0035, GSD is 1.8) and 0.005-0.033 (GM is 0.016, GSD is 2.1) accordingly. The highest CR values of uranium for mixed meadow grasses were found in the

  17. Spatial variability of initial 230Th/ 232Th in modern Porites from the inshore region of the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Clark, Tara R.; Zhao, Jian-xin; Feng, Yue-xing; Done, Terry J.; Jupiter, Stacy; Lough, Janice; Pandolfi, John M.

    2012-02-01

    The main limiting factor in obtaining precise and accurate uranium-series (U-series) ages of corals that lived during the last few hundred years is the ability to constrain and correct for initial thorium-230 ( 230Th 0), which is proportionally much higher in younger samples. This is becoming particularly important in palaeoecological research where accurate chronologies, based on the 230Th chronometer, are required to pinpoint changes in coral community structure and the timing of mortality events in recent time (e.g. since European settlement of northern Australia in the 1850s). In this study, thermal ionisation mass spectrometry (TIMS) U-series dating of 43 samples of known ages collected from living Porites spp. from the far northern, central and southern inshore regions of the Great Barrier Reef (GBR) was performed to spatially constrain initial 230Th/ 232Th ( 230Th/ 232Th 0) variability. In these living Porites corals, the majority of 230Th/ 232Th 0 values fell within error of the conservative bulk Earth 230Th/ 232Th atomic value of 4.3 ± 4.3 × 10 -6 (2 σ) generally assumed for 230Th 0 corrections where the primary source is terrestrially derived. However, the results of this study demonstrate that the accuracy of 230Th ages can be further improved by using locally determined 230Th/ 232Th 0 values for correction, supporting the conclusion made by Shen et al. (2008) for the Western Pacific. Despite samples being taken from regions adjacent to contrasting levels of land modification, no significant differences were found in 230Th/ 232Th 0 between regions exposed to varying levels of sediment during river runoff events. Overall, 39 of the total 43 230Th/ 232Th 0 atomic values measured in samples from inshore reefs across the entire region show a normal distribution ranging from 3.5 ± 1.1 to 8.1 ± 1.1 × 10 -6, with a weighted mean of 5.76 ± 0.34 × 10 -6 (2 σ, MSWD = 8.1). Considering the scatter of the data, the weighted mean value with a more

  18. U, Ra and Ba incorporation during precipitation of hydrothermal carbonates: Implications for {sup 226}Ra-Ba dating of impure travertines

    SciTech Connect

    Rihs, S.; Condomines, M.; Sigmarsson, O.

    2000-02-01

    The authors studied U, Ra and Ba incorporation in calcite in a natural CO{sub 2}-rich hydrothermal area from the French Massif Central. Along the western border of the Limagne graben, several springs are exploited for the petrification of various artifacts with calcite. These sites offer the opportunity to sample the water and the calcite layers downflow from the spring, and thus to follow the evolution of their U, Ra and Ba contents as precipitation proceeds. Results show that the apparent partition coefficients of U, Ra and Ba between water and calcite decrease during precipitation for the three elements. The authors found no direct relation between this variation and the main factors able to influence the partition coefficient, such as precipitation rate, which suggests that the incorporation of these trace elements could result from a composite process of adsorption and coprecipitation. Ra and Ba have a similar behavior, with an apparent partition coefficient decreasing from 0.80 to 0.47 for Ra and 0.96 to 0.68 for Ba, resulting in a small ({le}10%) variation of the Ra/Ba ratio. The apparent partition coefficient of U decreases from 0.38 to 0.20. These apparent coefficients are much higher than equilibrium values but might be applicable to natural systems with high precipitation rates. The authors also investigated the possibility of using the decay of the {sup 226}Ra-excess, or the decrease of the ({sup 226}Ra)/Ba ratio to date older deposits. Whereas the {sup 226}Ra initial activity at the time of deposition has not remained constant, and cannot be used for dating, the ({sup 226}Ra)/Ba method gives better results, when appropriate corrections for detrital contamination in Ba are made. Mixing diagrams using Th as an indicator of contamination allow calculation of the ({sup 226}Ra)/Ba ratio of the pure carbonate component. The calculated ages of five travertine layers range from 330 to 800 years, suggesting a mean deposition rate of about 1 cm/yr. The

  19. Determination of (210)Pb and (226)Ra/(228)Ra in continental water using HIDEX 300SL LS-spectrometer with TDCR efficiency tracing and optimized α/β-discrimination.

    PubMed

    Eikenberg, J; Beer, H; Jäggi, M

    2014-11-01

    An analytical method for determination of (210)Pb, (226)Ra and (228)Ra is presented based on adsorption on 3M Empore RadDiscs, and measurement applying liquid scintillation spectrometry (LSC) after elution. The LSC measurement was performed with optimized α/β-discrimination and isotope standardization using the triple to double coincidence ratio (TDCR). The consistency of measurement results between radioactive parent-daughter pairs (210)Pb/(210)Bi, (226)Ra/(222)Rn and (228)Ra/(228)Ac was checked in long-term counting experiments and the influence ofinterference of in-growing daughters from (226)Ra into the β-spectrum of (228)Ra+(228)Ac was studied as well. Recommendations for optimized LSC (228)Ra measurement besides presence of (226)Ra are given. PMID:24637085

  20. High resolution photofission measurements and intermediate structure in /sup 232/Th

    SciTech Connect

    Zhang, H.

    1986-01-01

    The photofission cross section of /sup 232/Th was measured in the energy range 5.8-12 MeV with an average photon energy resolution of 600 eV. The gamma rays, variable in energy, were obtained from narrow (p,..gamma..) resonances in various nuclei. Intermediate structure was observed at subbarrier excitation energies. The average spacing of photofission resonances provided the first relatively direct determination of the energy of the second minimum of the fission barrier, relative to the ground state. The measured fission probability and various properties of the intermediate structure were found to agree with calculated values based on a double bumped fission barrier. The features of this barrier, a rather high first hump and a deep secondary well, are quite different from the predictions of current theoretical barrier calculations.

  1. 232Th(n,{gamma})233Th Thermal Reaction Cross-Section Measurement

    SciTech Connect

    Maidana, Nora L.; Vanin, Vito R.; Pascholati, Paulo R.; Helene, Otaviano; Castro, Ruy M.; Dias, Mauro S.; Koskinas, Marina F.

    2005-05-24

    The 232Th(n,{gamma})233Th thermal neutron-capture reaction cross section was measured using targets of {approx} 1.5 mg of high-purity metallic thorium irradiated in the IPEN IEA-R1m 5 MW pool research reactor. The 197Au(n,{gamma})198Au reaction was used to monitor the thermal and epithermal neutron fluxes in the irradiation position, which was found using the Westcott formalism. The residual gamma-ray activity was followed with an HPGe detector. The detector efficiency curve was fitted by the least-squares method applying covariance analysis to all uncertainties involved. The experimental result is {sigma}0 =7.20{+-}0.20 b, in agreement with previous published values.

  2. Prompt γ-rays from the Fast Neutron Induced Fission on 235,238U and 232Th

    NASA Astrophysics Data System (ADS)

    Lebois, M.; Wilson, J. N.; Halipré, P.; Leniau, B.; Matea, I.; Oberstedt, A.; Oberstedt, S.; Verney, D.

    Preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fast-neutron induced fission of 238U, 232Th and 235U were detected. Thick samples of around 50 g of 238U and 232Th are used for the first part of the experiment. An ionisation chamber containing ∼ 10 mg samples of 238U and 235U to provide a fission trigger is used for the second part of the experiment. Gamma rays have been detected using 17 high efficiency BaF2 detectors and 6 LaBr3 scintillator detectors.

  3. Systematics of the mean energy and the mean multiplicity of prompt neutrons originating from {sup 232}Th fission

    SciTech Connect

    Svirin, M. I.

    2012-12-15

    The cross section for the neutron-induced fission of {sup 232}Th target nuclei, {sigma}{sub f} (E{sub n}), was described within statistical theory. The spectra of the mean multiplicity, v-bar (E{sub n}), and the mean energy, E-bar(E{sub n}), of secondary neutrons accompanying {sup 232}Th fission induced by neutrons of energy extending up to E{sub n} = 20 MeV were analyzed on the basis of the chance structure of the cross section.

  4. Using 232Th to monitor dissolved and total detrital inputs to the ocean

    NASA Astrophysics Data System (ADS)

    Robinson, L. F.; Noble, T. L.; McManus, J. F.

    2007-12-01

    This study uses long lived thorium isotopes as a tracer for both total and dissolved detrital inputs to seawater over time. Th-232 in seawater is derived exclusively from detritus, and its presence in the dissolved phase results from partial dissolution of this material. 230Th is produced in situ at a predictable rate by the decay of uranium, and its subsequent removal by efficient adsorption onto settling particles provides a method to quantify both dissolved and total 232Th fluxes to the seafloor. Assuming a fixed Th-232 concentration in detritus allows calculation of detrital fluxes to the seafloor. Sediments were acid leached to extract adsorbed Th, and Th associated with carbonate phases. Select samples were also subject to total dissolution. Adsorbed (and total) core top ratios giving high dissolved (and total) Th-232 fluxes were measured in sediment cores from locations with high expected detrital inputs and vice versa. The absolute values of these fluxes are reasonable by comparison to global estimates of detrital inputs to the ocean. Down core results display higher 232Th/230Th ratios that are consistent with enhanced ice-age dust deposition in the central Atlantic, North Pacific and a Southern Ocean transect. In general the glacial increases indicated by both total and dissolved thorium are smaller than the order of magnitude changes recorded in high latitude ice cores. This new tracer may be used to evaluate a variety of scenarios regarding the ocean and atmosphere of the past, including dust fertilization schemes that link variations in paleo-productivity with changes in atmospheric carbon dioxide and global climate. The half-lives of both thorium isotopes are long enough to allow us to use our approach on sediments that span several glacial-interglacial cycles.

  5. 210Pb-226Ra chronology reveals rapid growth rate of Madrepora oculata and Lophelia pertusa on world's largest cold-water coral reef

    NASA Astrophysics Data System (ADS)

    Sabatier, P.; Reyss, J.-L.; Hall-Spencer, J. M.; Colin, C.; Frank, N.; Tisnérat-Laborde, N.; Bordier, L.; Douville, E.

    2011-12-01

    Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of corals from one of the world's largest known cold-water coral reef, the Røst Reef off Norway. Two large branching framework-forming cold-water coral specimens, one Lophelia pertusa and one Madrepora oculata were collected alive at 350 m water depth from the Røst Reef at ~67° N and ~9° E. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and the corals trace element compositions were studied using ICP-QMS. Due to the different chemical behaviors of Pb and Ra in the marine environment, 210Pb and 226Ra were not incorporated the same way into the aragonite skeleton of those two cold-water corals. Thus to assess of the growth rates of both specimens we have here taken in consideration the exponential decrease of initially incorporated 210Pb as well as the ingrowth of 210Pb from the decay of 226Ra. Moreover a~post-depositional 210Pb incorporation is found in relation to the Mn-Fe coatings that could not be entirely removed from the oldest parts of the skeletons. The 226Ra activities in both corals were fairly constant, then assuming constant uptake of 210Pb through time the 210Pb-226Ra chronology can be applied to calculate linear growth rate. The 45.5 cm long branch of M. oculata reveals an age of 31 yr and a~linear growth rate of 14.4 ± 1.1 mm yr-1, i.e. 2.6 polyps per year. However, a correction regarding a remaining post-depositional Mn-Fe oxide coating is needed for the base of the specimen. The corrected age tend to confirm the radiocarbon derived basal age of 40 yr (using 14C bomb peak) with a mean growth rate of 2 polyps yr-1. This rate is similar to the one obtained in Aquaria experiments under optimal growth conditions. For the 80 cm-long specimen of L. pertusa a remaining contamination of metal-oxides is observed for the middle and basal part of the coral skeleton, inhibiting similar accurate age

  6. Determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in drinking water using a single sample preparation procedure.

    PubMed

    Parsa, Bahman; Obed, Reynaldo N; Nemeth, William K; Suozzo, Gail P

    2005-12-01

    The current federal and New Jersey State regulations have greatly increased the number of gross alpha and radium tests for public and private drinking water supplies. The determination of radium isotopes in water generally involves lengthy and complicated processes. In this study, a new approach is presented for the determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in water samples. The method includes a single sample preparation procedure followed by alpha counting and gamma-ray spectroscopy. The sample preparation technique incorporates an EPA-approved co-precipitation methodology for gross alpha determination with a few alterations and improvements. Using 3-L aliquots of sample, spiked with 133Ba tracer, the alpha-emitting radionuclides are isolated by a BaSO4 and Fe(OH)3 co-precipitation scheme. First the gross alpha-particle activity of the sample is measured with a low-background gas-flow proportional counter, followed by radium isotopes assay by gamma-ray spectroscopy, using the same prepared sample. Gamma-ray determination of 133Ba tracer is used to assess the radium chemical recovery. The 224Ra, 226Ra, and 228Ra activities in the sample are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb/214Bi, and 228Ac, respectively. In cases where 224Ra determination is required, the gamma-ray counting should be performed within 2-4 d from sample collection. To measure 226Ra activity in the sample, the gamma-ray spectroscopy can be repeated 21 d after sample preparation to ensure that 226Ra and its progeny have reached the equilibrium state. At this point, the 228Ac equilibration with parent 228Ra is already established. Analysis of aliquots of de-ionized water spiked with NIST-traceable 230Th, 224Ra, 226Ra, and 228Ra standards demonstrated the accuracy and precision of this method. Various performance evaluation samples were also assayed for gross alpha as well as radium isotope activity determination using this procedure and the

  7. Measurement of fission products yields in the quasi-mono-energetic neutron-induced fission of 232Th

    NASA Astrophysics Data System (ADS)

    Naik, H.; Mukherji, Sadhana; Suryanarayana, S. V.; Jagadeesan, K. C.; Thakare, S. V.; Sharma, S. C.

    2016-08-01

    The cumulative yields of various fission products in the 232Th(n, f) reaction at average neutron energies of 5.42, 7.75, 9.35 and 12.53 MeV have been determined by using an off-line γ-ray spectrometric technique. The neutron beam was produced from the 7Li(p, n) reaction by using the proton energies of 7.8, 12, 16 and 20 MeV. The mass chain yields were obtained from the cumulative fission yields by using the charge distribution correction of medium energy fission. The fine structure in the mass yield distribution was interpreted from the point of nuclear structure effect. On the other hand, the higher yield around mass number 133-134 and 143-144 as well as their complementary products were explained based on the standard I and standard II asymmetric mode of fission. From the mass yield data, the average value of light mass (), heavy mass (), the average number of neutrons (< ν >) and the peak-to-valley (P / V) ratios at different neutron energies of present work and literature data were obtained in the 232Th(n, f) reaction. The different parameters of the mass yield distribution in the 232Th(n, f) reaction were compared with the similar data in the 232Th(γ, f) reaction at comparable excitation energy and a surprising difference was observed.

  8. High precision {sup 230}Th and {sup 232}Th in the Norwegian Sea and Denmark by thermal ionization mass spectrometry

    SciTech Connect

    Moran, S.B.; Hoff, J.A.; Edwards, R.L.

    1995-10-01

    Seawater samples (1-2 liters) were collected from the Norwegian Sea and Denmark Strait and analyzed for {sup 230}Th and {sup 232}Th using highly sensitive thermal ionization mass spectrometry (TIMS). Depth profiles of dissolved {sup 230}Th and {sup 232}Th are characterized by surface water minima (<1 fg/kg, <5 pg/kg), subsurface maxima (12 fg/kg, 134 pg/kg), and intermediate concentrations that progressively decrease toward the bottom ({approximately}5 fg/kg, {approximately}17 pg/kg), respectively. The lack of an increase in {sup 230}Th with depth is suggested to result from the short ventilation age of Norwegian Sea Deep Water combined with enhanced scavenging near the basin margins. The {sup 230}Th maximum is attributed to advection of high {sup 230}Th in the Arctic Intermediate Water, whereas the {sup 232}Th maximum may he related to a particulate source. The low dissolved {sup 230}Th and {sup 232}Th concentrations observed in the NADW formation regions implies a minor advective export of these long-lived Th tracers to the North Atlantic. 24 refs., 1 fig., 1 tab.

  9. Study on the radioactivity and soil-to-plant transfer factor of (226)Ra, (234)U and (238)U radionuclides in irrigated farms from the northwestern Saudi Arabia.

    PubMed

    Al-Hamarneh, Ibrahim F; Alkhomashi, N; Almasoud, Fahad I

    2016-08-01

    The present study addresses the soil-to-plant transfer factors (TFs) of (226)Ra, (234)U and (238)U for 13 types of vegetables and agricultural crops planted under semi-arid environment in the northwestern part of Saudi Arabia. Crop plants along with plant-growing soils were collected from selected farms, which are irrigated from the non-renewable Saq aquifer, and investigated for their radioactivity content by means of alpha spectrometry after applying a radiochemical separation procedure. Hence, TF data for plant roots, green parts (stem and leaves) and fruits were calculated and contrasted to those reported in the literature. Substantial differences were observed in the TFs of Ra and U radioisotopes among plant species. In crop fruits, eggplant exhibited the highest uptake of (226)Ra (TF value of 0.11), while beans (0.16) have the highest TF for (234)U and (238)U. The geometric mean TF values indicated that the crop roots tend to accumulate Ra and U about four to six-folds higher than fruits. The relation between TF values and soil concentrations showed a weak correlation. Activity ratios between radionuclides in crop plants indicated the preferential translocation of U in fruits than Ra even though Ra is more available for root uptake. The fruit/root (F/R) ratios obtained for the investigated plants shown that pepper had the smallest F/R ratios (0.07 ± 0.01, 0.12 ± 0.02 and 0.11 ± 0.02 for (226)Ra, (234)U and (238)U, respectively), while the highest F/R ratios were observed in potatoes (0.71 ± 0.15, 0.44 ± 0.10 and 0.40 ± 0.08 for (226)Ra, (234)U and (238)U, respectively). The TF and F/R ratios data of natural radionuclides in the study region can hopefully improve the scientific knowledge for future studies. PMID:27108351

  10. Measurements of radioactivity in Jamaican building materials and gamma dose equivalents in a prototype red mud house

    SciTech Connect

    Pinnock, W.R. )

    1991-11-01

    Concentrations of 226Ra, 232Th, and 40K measured in bauxite waste, local building materials, and soils are presented and used in model equations to estimate the effective gamma dose-equivalent increments over background in the center of a standard-sized room in a prototype house. Calculated and measured values compare reasonably well.

  11. Study of the violent collisions between 63Cu+232Th at 35 MeV/nucleon

    NASA Astrophysics Data System (ADS)

    Cibor, J.; Majka, Z.; Kozik, T.; Staszel, P.; Sosin, Z.; Hagel, K.; Li, J.; Lou, L.; Tezkratt, R.; Utley, D.; Wada, R.; Xiao, B.; Natowitz, J. B.

    1997-01-01

    A study of the decay of hot and heavy composite nuclei produced in the violent collisions between 63Cu and 232Th at 35A MeV is presented. The measurement of fission fragment correlations indicates that ~ 70% of the projectile linear momentum can be transferred to the fissioning system. Heavy reaction products were observed at a laboratory angle of θ=6° in coincidence with neutrons, light charged particles, and intermediate mass fragments. The dynamical aspects of the collisions between the projectile and target nuclei were investigated using the computer code CHIMERA which is based upon the molecular dynamics concept. Asymptotic characteristics of the reaction products were confronted with results of calculations of the tandem CHIMERA plus GEMINI codes. The data and model comparisons show that a composite system of mass as high as 275 amu and with an excitation energy ~ 1 GeV is formed in the most violent collisions. Some of the heavy reaction remnants are located on the fragment mass versus velocity plane inside the area where the evaporation residues resulting from the decay of the hot composite system are expected. A high neutron multiplicity associated with these events indicates their origin in the most dissipative events. However, a low cross section for the production of these remnants and the close similarity of their characteristics to the fission fragments do not allow more conclusive statements.

  12. Parity violation in {sup 232}Th neutron resonances above 250 eV

    SciTech Connect

    Sharapov, E. I.; Bowman, J. D.; Crawford, B. E.; Delheij, P. P. J.; Frankle, C. M.; Iinuma, M.; Knudson, J. N.; Lowie, L. Y.; Lynch, J. E.; Masaike, A.

    2000-02-01

    The analysis of parity nonconservation (PNC) measurements performed on {sup 232}Th by the TRIPLE Collaboration has been extended to include the neutron energy range of 250 to 1900 eV. Below 250 eV all ten statistically significant parity violations have the same sign. However, at higher energies PNC effects of both signs were observed in the transmission of longitudinally polarized neutrons through a thick thorium target. Although the limited experimental energy resolution precluded analysis in terms of the longitudinal asymmetry, parity violations were observed and the cross section differences for positive and negative neutron helicities were obtained. For comparison, a similar analysis was performed on the data below 250 eV, for which longitudinal asymmetries were obtained previously. For energies below 250 eV, the p-wave neutron strength functions for the J=1/2 and J=3/2 states were extracted: S{sub 1/2}{sup 1}=(1.68{+-}0.61)x10{sup -4} and S{sub 3/2}{sup 1}=(0.75{+-}0.18)x10{sup -4}. The data provide constraints on the properties of local doorway states proposed to explain the PNC sign effect in thorium. (c) 2000 The American Physical Society.

  13. [Toxic and cytogenetic effects induced in Allium cepa with low concenrations of Cd and 232th].

    PubMed

    Evseeva, T I; Maĭstrenko, T A; Geras'kin, S A; Belykh, E S; Kazakova, E V

    2005-01-01

    232Th (7.76 x 10(-7) M) and Cd (0.89 x 10(-8) M) in concentrations which do not exceed officially prescribed standards when entering with water do not increase the frequency of chromosome aberrations in comparison with the control. Such concentrations do not cause toxic effects in plants on the levels of tissues and of the whole organism but they do display their activity on the cell level damaging division spindle. Dependence "cadmium concentration-effect" is not linear for any type of cytogenetical damages. At the concentration of cadmium 0.89 x 10(-7) M its influence on formation of division spindle is weakened and the frequency of chromosome aberrations is reducing in comparison with the control and with the effects induced at lower concentrations of cadmium in solution (0.89 x 10(-8) M). Cadmium in high concentration (5.34 x 10(-5) M) causes significant toxic and mutagenic effects. PMID:16398149

  14. Fission following complete fusion for {sup 16}O + {sup 232}Th at 140 MeV

    SciTech Connect

    Frawley, A.D.

    1995-09-01

    Previously published results of coincidence measurements between incomplete fusion products and fission fragments from the reaction of 140 MeV {sup 16}O with {sup 232}Th have been used to determine the incomplete fusion contributions to the inclusive fission fragment angular distribution. The incomplete fusion contributions have been subtracted from the inclusive angular distribution, leaving the part due to complete fusion. Because the incomplete fusion processes account for 42% of the fission cross section, the maximum angular momentum contributing to complete fusion is reduced to approximately 55{h_bar}. The angular distribution for fission following complete fusion has been compared with calculations made with the saddle point transition state model and with Bond`s scission point model. When proper account is taken of the large reduction in nuclear temperature at the saddle point due to pre-fission neutron evaporation, the saddle point transition state model reproduces the data very well. Proper handling of the incomplete fusion contributions is found to greatly improve the agreement of Bond`s scission point model with the data for this reaction.

  15. Retardation of 238U and 232Th decay chain radionuclides in Long Island and Connecticut aquifers

    NASA Astrophysics Data System (ADS)

    Copenhaver, Sally A.; Krishnaswami, S.; Turekian, Karl K.; Epler, Nathan; Cochran, J. K.

    1993-02-01

    Knowledge of the ability of an aquifer to retard the groundwater transport of toxic or radioactive ions can be inferred from the analysis of groundwater for the radionuclides of the 238U- and 232Th-decay chains. Groundwaters of varying chemical composition were analyzed from wells in Long Island, New York, and Connecticut. Aquifer lithologies are arkose, quartz sandstone, granite, and glacial drift. Adsorption ( k1) and desorption ( k2) coefficients for Ra and Pb were calculated using 222Rn activity as a measure of the supply of other α-recoil nuclides. Laboratory tests of the validity of this assumption were made by measuring the flux of 224Ra and 222Rn from aquifer solids. The ratio k 1/k 2 is the distribution coefficient, K, which is effectively equal to R ƒ, the retardation factor. The average value of K for Ra is 6 × 10 2 in Long Island aquifers and 5 × 10 4 in Connecticut. The distribution coefficient for Pb is 10 4 in Long Island and 10 5 in Connecticut. Results from this and other studies reveal a strong dependence of retardation on pH, ƒ O 2, and ionic strength that tends to overwhelm any dependence of retardation on lithology.

  16. Abundance of low-energy gamma rays in the decay of 238U, 234U, 230Th, 227Ac, 226Ra and 214Pb

    NASA Astrophysics Data System (ADS)

    Komura, K.; Yamamoto, M.; Ueno, K.

    1990-11-01

    Abundance of low-energy gamma rays emitted from 238U (49.5 keV), 227Ac (50.0 keV), 234U (53.2 keV), 214Pb (53.2 keV), 230Th (67.7 and 143.9 keV) and 226Ra (186 keV) was determined using a high-purity Ge low energy photon spectrometer. The results are: 49.5 keV (238U): 0.059±0.002%, 50.0 keV (227Ac): 8.18±0.17%, 53.2 keV (234U): 0.156±0.006%, 53.2 keV (214Pb): 0.927±0.025%, 67.7 keV (230Th): 0.463±0.012%, 143.9 keV (230Th): 0.078±0.007%, 186.0 keV (226Ra): 3.688±0.099%.

  17. Study of 232Th(n, γ) and 232Th(n,f) reaction rates in a graphite moderated spallation neutron field produced by 1.6 GeV deuterons on lead target

    NASA Astrophysics Data System (ADS)

    Asquith, N. L.; Hashemi-Nezhad, S. R.; Westmeier, W.; Zhuk, I.; Tyutyunnikov, S.; Adam, J.

    2015-02-01

    The Gamma-3 assembly of the Joint Institute for Nuclear Research (JINR), Dubna, Russia is designed to emulate the neutron spectrum of a thermal Accelerator Driven System (ADS). It consists of a lead spallation target surrounded by reactor grade graphite. The target was irradiated with 1.6 GeV deuterons from the Nuclotron accelerator and the neutron capture and fission rate of 232Th in several locations within the assembly were experimentally measured. 232Th is a proposed fuel for envisaged Accelerator Driven Systems and these two reactions are fundamental to the performance and feasibility of 232Th in an ADS. The irradiation of the Gamma-3 assembly was also simulated using MCNPX 2.7 with the INCL4 intra-nuclear cascade and ABLA fission/evaporation models. Good agreement between the experimentally measured and calculated reaction rates was found. This serves as a good validation for the computational models and cross section data used to simulate neutron production and transport of spallation neutrons within a thermal ADS.

  18. Development of a method for activity measurements of 232Th daughters with a multidetector gamma-ray coincidence spectrometer.

    PubMed

    Antovic, N; Svrkota, N

    2009-06-01

    The method for activity measurements of the (232)Th daughters, developed at the six-crystal gamma-ray coincidence spectrometer PRIPYAT-2M and based on coincidence counting of the 583 and 2615 keV photons from cascade transitions which follow beta(-)-decay of (208)Tl, as well as on counting the 911 keV photons which follow beta(-)-decay of (228)Ac in the integral and non-coincidence mode of counting, is presented. PMID:19299155

  19. Reaction product characteristics of the 65Cu+232Th violent collision at 35MeV/nucleon

    SciTech Connect

    Majka, Z.; Cibor, J.; Kozik, T.

    1995-12-01

    An exclusive experiment that imposed strong restrictive conditions has been performed at the Texas A&M K-500 superconducting cyclotron facility to study the formation and decay of hot nuclear system in the 35 AMeV 63Cu+232Th collision. Dynamical aspects of the collision between the projectile and target were simulated by the computer code CHIMERA which is based on the molecular dynamics concept.

  20. ({sup 16}O + {sup 232}Th) incomplete fusion followed by fission at 140 MeV

    SciTech Connect

    Gavathas, E.P.

    1993-12-31

    Cross sections for incomplete fusion followed by fission have been measured for the reaction ({sup 16}O + {sup 232}Th) at 140 MeV. In plane and out of plane measurements were made of cross sections for beamlike fragments in coincidence with fission fragments. The beamlike fragments were detected with the Florida State large acceptance Bragg curve spectrometer. The detector was position sensitive in the polar direction. The beamlike particles observed in coincidence with fission fragments were He, Li, Be, B, C, N and O. Fission fragments were detected by three surface barrier detectors using time of flight for particle identification. The reaction cross section due to incomplete fusion is 747 {+-} 112 mB, or 42% of the total fission cross section. The strongest incomplete fusion channels were the helium and carbon channels. The average transferred angular momentum for each incomplete fusion channel was calculated using the Q{sub opt} model of Wilczynski, and the angular correlation was calculated using the saddle point transition state model. The K distribution was determined from the Rotating Liquid Drop model. The theoretic angular distributions were fitted to the experimental angular distributions with the angular momentum J and the dealignment factor {alpha}{sub 0} as free parameters. The fitted parameter J was in excellent agreement with the Q{sub opt} model predictions. The conclusions of this study are that the incomplete fusion cross section is a large part of the total cross section, and that the saddle point transition state model adequately describes the observed angular correlations for fission following incomplete fusion.

  1. Concurrent determination of 224Ra, 226Ra, 228Ra, and unsupported 212Pb in a single analysis for drinking water and wastewater: dissolved and suspended fractions.

    PubMed

    Parsa, Bahman; Obed, Reynaldo N; Nemeth, William K; Suozzo, Gail

    2004-02-01

    A technique has been developed for the measurement of 224Ra, 226Ra, 228Ra, and unsupported 2t2Pb concurrently in a single analysis. The procedure can be applied to both drinking water and wastewater, including the dissolved and suspended fractions of a sample. For drinking water samples, using 3-L aliquots, the radium isotopes are isolated by a fast PbSO4 co-precipitation and then quantified by gamma-ray spectroscopy. The radium isotopes 224Ra, 226Ra, and 228Ra are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb (and/or 214Bi), and 228Ac, respectively. Because of the short half-life of 224Ra (T1/2 = 3.66 d), the precipitate should be counted within 4 d of the sample collection date. In case the measurement of unsupported 212Pb (T1/2 = 10.64 h) is required, the gamma-ray analysis should be initiated as soon as possible, preferably on the same day of collection. The counting is repeated after about 21 d to ensure the 226Ra progeny are in equilibrium with their parent. At this point, the 228Ac equilibration with its 228Ra parent is already established. In the case of samples containing suspended materials, an aliquot of sample is filtered and then the filtrate is treated as described above for drinking water samples. The suspended fraction of sample, collected on the filter, is directly analyzed by gamma-ray spectroscopy with no further chemical separation. Aliquots of de-ionized water spiked with various radium standards were analyzed to check the accuracy and precision of the method. In addition, analysis results of actual samples using this method were compared with the ones performed using U.S. Environmental Protection Agency-approved procedures, and the measured values were in close agreement. This method simplifies the analytical procedures and reduces the labor while achieving the precision, accuracy, and minimum detection concentration requirements of EPA's Regulations. PMID:14744047

  2. Ground water contamination with (238)U, (234)U, (235)U, (226)Ra and (210)Pb from past uranium mining: cove wash, Arizona.

    PubMed

    Dias da Cunha, Kenya Moore; Henderson, Helenes; Thomson, Bruce M; Hecht, Adam A

    2014-06-01

    The objectives of the study are to present a critical review of the (238)U, (234)U, (235)U, (226)Ra and (210)Pb levels in water samples from the EPA studies (U.S. EPA in Abandoned uranium mines and the Navajo Nation: Red Valley chapter screening assessment report. Region 9 Superfund Program, San Francisco, 2004, Abandoned uranium mines and the Navajo Nation: Northern aum region screening assessment report. Region 9 Superfund Program, San Francisco, 2006, Health and environmental impacts of uranium contamination, 5-year plan. Region 9 Superfund Program, San Franciso, 2008) and the dose assessment for the population due to ingestion of water containing (238)U and (234)U. The water quality data were taken from Sect. "Data analysis" of the published report, titled Abandoned Uranium Mines Project Arizona, New Mexico, Utah-Navajo Lands 1994-2000, Project Atlas. Total uranium concentration was above the maximum concentration level for drinking water (7.410-1 Bq/L) in 19 % of the water samples, while (238)U and (234)U concentrations were above in 14 and 17 % of the water samples, respectively. (226)Ra and (210)Pb concentrations in water samples were in the range of 3.7 × 10(-1) to 5.55 × 102 Bq/L and 1.11 to 4.33 × 102 Bq/L, respectively. For only two samples, the (226)Ra concentrations exceeded the MCL for total Ra for drinking water (0.185 Bq/L). However, the (210)Pb/(226)Ra ratios varied from 0.11 to 47.00, and ratios above 1.00 were observed in 71 % of the samples. Secular equilibrium of the natural uranium series was not observed in the data record for most of the water samples. Moreover, the (235)U/(total)U mass ratios ranged from 0.06 to 5.9 %, and the natural mass ratio of (235)U to (total)U (0.72 %) was observed in only 16 % of the water samples, ratios above or below the natural ratio could not be explained based on data reported by U.S. EPA. In addition, statistical evaluations showed no correlations among the distribution of the radionuclide concentrations

  3. Assessing the reliability of dose coefficients for ingestion and inhalation of 226Ra and 90Sr by members of the public.

    PubMed

    Puncher, M

    2014-01-01

    Assessments of risk to a population group resulting from internal exposure to a particular radionuclide can be used to assess the reliability of the appropriate International Commission on Radiological Protection (ICRP) dose coefficient, E(50), used as a radiation protection device for the specified exposure pathway. An estimate of the uncertainty on the risk is important for informing judgements on reliability. This paper describes the application of parameter uncertainty analysis to quantify uncertainties resulting from internal exposures to radioisotopes of the alkaline earth metals, (90)Sr and (226)Ra, by members of the UK public. The study derives uncertainties in biokinetic model parameter values to calculate the distributions of the effective dose per unit intake using the ICRP Publication 60 formalism. The distributions are used to infer the uncertainty on the mean effective dose per unit intake to inform the derivation of uncertainty factors (UF) for the appropriate ICRP Publication 72 dose coefficients. Here, a UF indicates a 95 % probability that the best estimate of risk per unit intake is within a factor, UF, of the nominal risk associated with the appropriate ICRP dose coefficient, E(50), with respect to uncertainties in the biokinetic model parameter values. Ingestion: it is assumed that exposure occurs through the ingestion of radionuclides present in food and water. The results for both radionuclides suggest a UF of within 3 for all age groups, with median values close to the ICRP values. Inhalation: it is assumed that environmental exposure to radium occurs primarily due to insoluble forms present in fly ash discharged from coal-fired power stations; for strontium, exposure is assumed to occur due to residual aerosols produced as a result of atmospheric nuclear testing and nuclear reactor accidents. The results suggest a UF of around 3 and 6 for inhalation of (90)Sr and (226)Ra, respectively, by members of the public. PMID:23896416

  4. High-resolution photofission measurements in /sup 238/U and /sup 232/Th. Progress report, June 1, 1980-February 10, 1981

    SciTech Connect

    Lancman, H.

    1981-02-01

    Intense proton beam currents from the Dynamitron at Brooklyn College have been used to generate gamma rays of variable energy from a number of (p,..gamma..) resonances in various nuclei. Spectra of photofission fragments of /sup 238/U and /sup 232/Th have been measured with an average gamma ray energy resolution of approx. 300 eV. Structure in the photofission cross section of /sup 232/Th was observed at approx. 6176 keV.

  5. Spatial and Temporal Distribution of Initial 230TH/232TH in Sumatran Corals and its Influence on the Accurate Dating of Young Corals

    NASA Astrophysics Data System (ADS)

    Chiang, H.; Shen, C.; Meltzner, A. J.; Philibosian, B.; WU, C.; Sieh, K. E.; Wang, X.

    2012-12-01

    Accurate and precise determination of initial 230Th/232Th (230Th/232Th0) is important in dating young fossil corals, and it can significantly influence our understanding of paleoclimate, paleoceanographic and paleoseismic histories. A total of 47 unpublished and published isochrons (Shen et al., 2008; Meltzner et al., 2010, 2012; Philibosian et al., 2012), covering most of the Sumatran outer-arc islands, provide a more robust estimate of the 230Th/232Th0 variability in the region. The weighted average of 230Th/232Th0 atomic values is 4.7 (+5.5/-4.7) × 10-6 (2σ), consistent with the previously reported value of 6.5 ± 6.5 × 10-6 obtained from a handful of samples from the southern part of Sumatran outer-arc. Specifically, the calculated 230Th/232Th0 in the north and south are identical. The weighted mean of 3.5 (+7.0/-3.5) × 10-6 for fossil corals of 300-2000-yr old is slightly lower than the value of 5.4 ± 4.5 × 10-6 obtained from corals younger than 300 yrs B.P.. For corals containing less than 2 ppb of thorium, however, the age offset will be less than 10 yr by using different 230Th/232Th0, which is acceptable for most studies. We hereby recommend an updated 230Th/232Th0 value of 4.7 (+5.5/-4.7) × 10-6 for corals throughout the Sumatran outer-arc islands. For very high-precision age determination (<10 yr), coral samples with low Th concentration (< 2 ppb) are preferred.; ;

  6. Duration of gas accumulation before the 2010 Eyjafjallajökull eruption constrained by 210Po-210Pb-226Ra disequilibria

    NASA Astrophysics Data System (ADS)

    Sigmarsson, Olgeir; Gauthier, Pierre-Jean; Condomines, Michel

    2014-05-01

    Excess gas phase in magmas erupting explosively is well known world-wide. However, the origin of this gas phase, in excess of what can be dissolved in the erupting magma at depth, and the duration of gas accumulation, is less well defined. The 2010 mildly explosive eruption at Eyjafjallajökull, Iceland, produced mingled tephra of benmoreiitic and trachytic composition whereas alkali basalt (MgO > 8 %) was emitted during the preceding flank eruption. The silicic tephra of the first explosive phase is composed of three glass types, alkaline rhyolite, mixed benmoreiite, and evolved basalt (MgO < 5 %). The rhyolitic glass is indistinguishable from tephra glass composition emitted during the penultimate eruption of Eyjafjallajökull in 1821-23 AD (Sigmarsson et al., 2011). Tephra from the first explosive phase, emitted on 15 and 17 April, had large 210Po in excess of 210Pb ((210Po/210Pb)0 as high as 2!) and a small, but significant, 210Pb excess over its parent 226Ra ((210Pb/226Ra)0= 1.05 and 1.04, respectively). These excesses suggest rapid accumulation of Po and Rn together with the major gas species in the residual rhyolitic magma from the 1821-23 eruption. The gas most likely originates from the basalt recharge that eventually provoked the eruption. Basalts emitted a month earlier during the flank eruption at Fimmvörðuháls lost all their Po upon eruption and had (210Po/210Pb)0 equal to 0). From a simple model of radon and polonium degassing and accumulation, the mass of basalt magma degassing over the mass of silicic magma accumulating the excess gas can be calculated. Moreover, the duration of gas accumulation can be shown to be close to 300 days. This duration suggests that gas was liberated from the basaltic magma since June 2009, a month that corresponds to the initial seismic swarm beneath Eyjafjallajökull preceding the explosive eruption of 14 April 2010.

  7. Independent yields from the photofission of sup 232 Th, and the Z sub p and statistical-dynamic models

    SciTech Connect

    Smith, J.R.; Richardson, A.E. )

    1991-09-01

    Independent fission yields were measured for {sup 82}Br, {sup 96}Nb, {sup 124}Sb, and {sup 126}Sb produced by photofission of {sup 232}Th with 27-MeV peak bremsstrahlung and for {sup 136}Cs at 11, 15, and 27 MeV. Upper limits for the independent yields for {sup 86}Rb and {sup 134}Cs and mass yields for mass chains 125 and 127 were also measured for {sup 232}Th photofission at 27 MeV. Various extensions of the {ital Z}{sub {ital p}} charge-distribution model were found to give generally good agreement with experimental measurements in the asymmetric mass regions, but less satisfactory agreement in the symmetric region. A statistical charge-distribution model incorporating post-fission dynamics correlated well with experimental values in both symmetric and asymmetric regions. The statistical-dynamic model naturally predicted pairing and shell effects which were in good agreement with experimentally observed effects. One important outcome of the statistical-dynamic model calculations was the production of a linear shape on the wings of the charge-distribution curve when proximity proton transfer after scission was incorporated into the model. Such linear shapes have previously been experimentally observed without explanation.

  8. Covariances of Evaluated Nuclear Cross Section Data for (232)Th, (180,182,183,184,186)W and (55)Mn

    SciTech Connect

    Trkov, A.; Capote, R.; Soukhovitskii, E; Leal, Luiz C; Sin, M; Kodeli, I.; Muir, D W

    2011-01-01

    The EMPIRE code system is a versatile package for nuclear model calculations that is often used for nuclear data evaluation. Its capabilities include random sampling of model parameters, which can be utilized to generate a full covariance matrix of all scattering cross sections, including cross-reaction correlations. The EMPIRE system was used to prepare the prior covariance matrices of reaction cross sections of (232)Th, (180,182,183,184,186)W and (55)Mn nuclei for incident neutron energies up to 60 MeV. The obtained modeling prior was fed to the GANDR system, which is a package for a global assessment of nuclear data, based on the Generalized Least-Squares method. By introducing experimental data from the EXFOR database into GANDR, the constrained covariance matrices and cross section adjustment functions were obtained. Applying the correction functions on the cross sections and formatting the covariance matrices, the final evaluations in ENDF-6 format including covariances were derived. In the resonance energy range, separate analyses were performed to determine the resonance parameters with their respective covariances. The data files thus obtained were then subjected to detailed testing and validation. Described evaluations with covariances of (232)Th, (180,182,183,184,186)W and (55)Mn nuclei are included into the ENDF/B-VII.1 library release.

  9. Natural radioactivity and associated dose rates in soil samples from Kalpakkam, South India.

    PubMed

    Sowmya, M; Senthilkumar, B; Seshan, B R R; Hariharan, G; Purvaja, R; Ramkumar, S; Ramesh, R

    2010-10-01

    The activity concentration of naturally occurring radioactive elements such as 226Ra, 232Th and 40K were measured for 46 soil samples collected in the vicinity of the Madras atomic power station, Kalpakkam, South India using gamma-ray spectroscopy. The average activity concentration of 226Ra, 232Th and 40K in soil samples were found to be 22.6 ± 12.6, 92.8 ± 44.3 and 434.1 ± 131.1 Bq kg(-1), respectively. The activity concentration of natural radionuclides is higher than the world average except for (226)Ra. The external absorbed gamma dose rates due to 226Ra, 232Th and 40K are observed to be 74.6 ± 30.8 nGy h(-1) with a corresponding annual effective dose of 91.5 ± 37.8 µSv y(-1), which are also above the world average. The values of radium equivalent activity and external hazard index are less than the world average. Whereas, the values of the radioactivity level index (I(γ)) and the total gamma dose rate were found to be above the required criterion. PMID:20522563

  10. Relative radiosensitivity of bone tumor induction among beagles as a function of age at injection of {sup 239}Pu or {sup 226}Ra

    SciTech Connect

    Lloyd, R.D.; Taylor, G.N.; Jee, W.S.S.; Miller, S.C.

    1999-01-01

    A comparison was made of the response to induction of skeletal malignancy from exposure of beagles to monomeric {sup 239}Pu or to {sup 226}Ra as juveniles (3 mo of age), young adults (1.5 y of age), or mature adults (5 y of age). This indicated that of these age groups, animals injected as young adults are most sensitive per Gy of average skeletal dose evaluated at 1 y before death. Dogs exposed either as juveniles or as mature adults appeared to be less sensitive. Relative radiosensitivities (RRS) of juvenile and mature beagles ranged between about 0.3 and 0.7 that of dogs injected as young adults. Mean values of RRS for both radionuclides were about 0.5, but RRS values derived from dogs given monomeric {sup 239}Pu appeared to be most reliable and were 0.27 {+-} 0.09 for dogs injected as juveniles and 0.41 {+-} 0.13 for animals exposed as mature adults.

  11. Flank eruptions of Mt Etna during the Greek-Roman and Early Medieval periods: New data from 226Ra-230Th dating and archaeomagnetism

    NASA Astrophysics Data System (ADS)

    Branca, Stefano; Condomines, Michel; Tanguy, Jean-Claude

    2015-10-01

    In this paper, we present new data from 226Ra-230Th dating and archaeomagnetism with the aim of improving the knowledge of the flank eruptions that occurred at Mt Etna during the Greek-Roman and Early Medieval periods, as defined in the new geological map of the volcano. The combination of the two dating techniques demonstrates that three major flank eruptions occurred on the lower north and west flanks during Greek-Roman epochs, producing large scoria cones and extensive lava flows. In particular, the Mt Ruvolo and Mt Minardo events highly impacted the territory of the west flank, notably by damming the Simeto River. The new data of the Millicucco and Due Monti lava flows, on the lower north-east flank, indicate a younger age than their stratigraphic ages quoted in the 2011 geological map, since they occurred around 700 and 500 AD, respectively. None of the large flank eruptions occurring on the lower slopes of Etna during the Early Medieval age are reported in the historical sources. Overall, our paper shows that a comprehensive assessment of eruptions at Mount Etna in the last three millennia can only be achieved through a multidisciplinary approach.

  12. Current (1984) status of the study of /sup 226/Ra and /sup 228/Ra in humans at the Center for Human Radiobiology

    SciTech Connect

    Rundo, J.; Keane, A.T.; Lucas, H.F.; Schlenker, R.A.; Stebbings, J.H.; Stehney, A.F.

    1984-01-01

    The Center for Human Radiobiology has identified 5784 persons by name and type of exposure to /sup 226/Ra and /sup 228/Ra. Included are 4863 dial painters (mostly women) and non-laboratory employees of the radium dial industry, 410 laboratory workers, 399 persons who received radium for supposed therapeutic effects, and 112 in other categories. Body contents of radium have been measured in 1916 of the dial workers and about one-half of the subjects in the other groups. Bone sarcomas, carcinomas of the paranasal sinuses and mastoids, and deterioration of skeletal tissue are still the only effects unequivocally attributable to internal radium. Excess leukemias have not been observed and other malignancies, if in excess, appear more likely to be related to external gamma radiation or radon than to internal radium. Positive correlations with radium burdens have been found for the incidence of benign exostoses among subjects exposed to radium before age 18 and for shortened latency of ocular cataracts. 26 references, 3 figures, 5 tables.

  13. Ce-Fe-modified zeolite-rich tuff to remove Ba(2+)-like (226)Ra(2+) in presence of As(V) and F(-) from aqueous media as pollutants of drinking water.

    PubMed

    Olguín, María Teresa; Deng, Shuguang

    2016-01-25

    The sorption behavior of the Ba(2+)-like (226)Ra(2+) in the presence of H2AsO4(-)/HAsO4(2-) and F(-) from aqueous media using Ce-Fe-modified zeolite-rich tuff was investigated in this work. The Na-modified zeolite-rich tuff was also considered for comparison purposes. The zeolite-rich tuff collected from Wyoming (US) was in contact with NaCl and CeCl3-FeCl3 solutions to obtain the Na- and Ce-Fe-modified zeolite-rich tuffs (ZUSNa and ZUSCeFe). These zeolites were characterized by scanning electron microscopy and X-ray diffraction. The BET-specific surface and the points of zero charge were determined as well as the content of Na, Ce and Fe by neutron activation analysis. The textural characteristics and the point of zero charge were changed by the presence of Ce and Fe species in the zeolitic network. A linear model described the Ba(2+)-like (226)Ra(2+) sorption isotherms and the distribution coefficients (Kd) varied with respect to the metallic species present in the zeolitic material. The As(V) oxianionic chemical species and F(-) affected this parameter when the Ba(2+)-like (226)Ra(2+)-As(V)-F(-) solutions were in contact with ZUSCeFe. The H2AsO4(-)/HAsO4(2-) and F(-) were adsorbed by ZUSCeFe in the same amount, independent of the concentration of Ba(2+)-like (226)Ra(2+) in the initial solution. PMID:26476322

  14. Curtiss P-40K Warhawk

    NASA Technical Reports Server (NTRS)

    1943-01-01

    Curtiss P-40K Warhawk: The Curtiss P-40K Warhawk was an improved version of the P-40E. This Warhawk was used by the NACA at Langley from July of 1942 until October of 1944. The P-40 gained most of its fame as the mount of the American Volunteer Group (AVG) 'Flying Tigers.' But shark mouthed P-40s were also flown by the Royal Air Force in North Africa.

  15. Yield and cross section of {sup 232}Th and {sup 236}U fission induced by {gamma} quanta with energies up to 11 MeV

    SciTech Connect

    Soldatov, A.S.; Smirenkin, G.N.

    1995-02-01

    The results of relative measurements of photofission yields are presented for {sup 232}Th and {sup 236}U nuclei in the region 7-11 MeV of end-point bremsstrahlung energies. The cross section and yield of {sup 238}U photofission is taken as the standard. The photofission cross sections for the {sup 232}Th and {sup 236}U nuclei are reconstructed from these data. The experimental data processing is refined, and the information obtained is revised. This paper is a continuation of the earlier publication. 21 refs., 5 figs.

  16. {gamma}-ray decays in {sup 232}Th and the K{sup {pi}}=4{sup +} two-phonon {gamma} vibration

    SciTech Connect

    Martin, A.; Garrett, P. E.; Kadi, M.; Warr, N.; McEllistrem, M. T.; Yates, S. W.

    2000-12-01

    A recent Coulomb excitation study has called into question the 4{sup +} spin assignment of the 1414-keV level in {sup 232}Th, which had earlier been interpreted as a two-phonon {gamma}-vibrational excitation, and had suggested instead a 3{sup -} assignment. Data obtained in the present neutron scattering study of {sup 232}Th are inconsistent with the 3{sup -} suggestion and support an I{sup {pi}}=4{sup +} assignment for the 1414-keV level, lending credence to the argument that it is a K{sup {pi}}=4{sup +} band head.

  17. Influence of /sup 226/Ra on bone marrow stem cells in mice: effect of radium decorporation by a long-term treatment with Na-alginate on stem-cell damage

    SciTech Connect

    Schoeters, G.; Van Puymbroeck, S.; Vanderborght, O.

    1980-04-01

    Three-month old male BALB/c mice were injected intraperitoneally with /sup 226/RaCl/sub 2/ at dose levels of 4.5, 6.9, 9.0, and 13.5 ..mu..Ci /sup 226/Ra/kg body wt. At the two highest doses, the number of multipotential bone marrow stem cells was severely depressed 8 weeks after the injection. By 30 weeks no depression was observed compared to controls. The number of peripheral red blood cells was never altered, while the number of white blood cells was slghtly depressed after 8 weeks of contamination. Mice fed every other week with standard pellets and on alternate weeks with a diet containing 6% Na-alginate (first given 12 days after the injection of /sup 226/RaCl/sub 2/) showed a significant reduction of stem-cell depression 8 and 12 weeks after contamination in three of the six treatment groups with manifest radiation effects on the stem cells.

  18. Sensitivity of large-scale neutrino detector to 40K geoneutrinos

    NASA Astrophysics Data System (ADS)

    Ungar, Yocheved

    2015-10-01

    Uranium, Thorium and Potassium are the primary radioactive constituents of Earth's mantle and crust. Neutrinos released during the decay of these radioactive elements can be used to directly study the bulk composition of Earth's interior. While existing detectors such as a KamLand and Borexino have detected 232Th and 238U, they do not have the sensitivity to observe the low energy (<1.8 MeV) 40K geoneutrinos. 40K geoneutrinos have been predicted to be the most abundant of the radioactive elements in Earth's interior and therefore are of particular interest. I am studying the feasibility of using a large scale (1000 ton) scintillator based detector to search for 40K geoneutrinos that interact with the scintillator through the process of antineutrino-electron scattering. I will present the results of calculations of neutrino flux predictions and the expected number of scattering events in a kiloton-scale detector as well as studies of backgrounds and their effect on the viability of detecting 40K geoneutrinos.

  19. Mount Etna eruptions of the last 2,750 years: revised chronology and location through archeomagnetic and 226Ra-230Th dating

    NASA Astrophysics Data System (ADS)

    Tanguy, Jean-Claude; Condomines, Michel; Le Goff, Maxime; Chillemi, Vito; La Delfa, Santo; Patanè, Giuseppe

    2007-09-01

    A careful re-examination of the well-known written documents pertaining to the 2,750-year-long historical period of Mount Etna was carried out and their interpretation checked through the high-accuracy archeomagnetic method (>1,200 large samples), combined with the 226Ra-230Th radiochronology. The magnetic dating is based upon secular variation of the direction of the geomagnetic field (DGF) and estimated to reach a precision of ±40 years for the last 1,200 years, and ±100 to 200 years up to circa 150 B.C. Although less precise, the 226Ra-230Th method provides a unique tool for distinguishing between historic and prehistoric lavas, which in some cases might have similar DGFs. We show that despite the abundance of details on ancient historical eruptions, the primary sources of information are often too imprecise to identify their lava flows and eruptive systems. Most of the ages of these lavas, which are today accepted on the geological maps and catalogues, were attributed in the 1800s on the basis of their morphology and without any stratigraphical control. In fact, we found that 80% of the “historically dated” flows and cones prior to the 1700s are usually several hundreds of years older than recorded, the discrepancies sometimes exceeding a millennium. This is proper the case for volcanics presumed of the “1651 east” (actually ˜1020), “1595” (actually two distinct flows, respectively, ˜1200 and ˜1060), “1566” (˜1180), “1536” (two branches dated ˜1250 and ˜950), “1444” (a branch dated ˜1270), “1408” (lower branches dated ˜450 and ˜350), “1381” (˜1160), “1329” (˜1030), “1284” (˜1450 and ˜700), “1169 or 812” (˜1000) eruptions. Conversely, well-preserved cones and flows that are undated on the maps were produced by recent eruptions that went unnoticed in historical accounts, especially during the Middle Ages. For the few eruptions that are recorded between A.D. 252 and 750 B.C., none of their presumed lava

  20. A comparison of the natural survival of beagle dogs injected intravenously with low levels of 239Pu, 226Ra, 228Ra, 228Th, or 90Sr.

    PubMed

    Bruenger, F W; Miller, S C; Lloyd, R D

    1991-06-01

    The natural survival, relative to properly chosen controls, of 26 beagle dogs injected once intravenously with an average of 0.58 +/- 0.04 kBq 239Pu/kg, 23 dogs injected with 2.31 +/- 0.43 kBq 226Ra/kg, 13 dogs injected with 1.84 +/- 0.26 kBq 228Ra/kg, 12 dogs injected with 0.56 +/- 0.030 kBq 228Th/kg, and 12 dogs injected with 21.13 +/- 1.74 kBq 90Sr/kg was evaluated statistically. The amounts of these radionuclides are related directly to the estimated maximum permissible body burdens for humans suggested in ICRP II (1959). They constitute a level of exposure that initially was assumed to cause no deleterious effects in dogs. This study had two objectives: (1) identification of homogeneous control groups against which to evaluate the survival of the irradiated groups and (2) comparison of the survival characteristics and estimation of mortality or hazard rate ratios for control dogs vs dogs injected with the baseline dosages given above. It was shown, by goodness-of-fit plots, that the Cox proportional hazards model was an appropriate method of analysis. Therefore, covariates that possibly could influence survival were tested for significance. Only the effects of grand mal seizure, which is caused in epileptic dogs by an external stimulus and can be fatal if untreated, were significant (P less than 0.0001). Consequently, in the final model, death from grand mal seizure was considered as accidental. After censoring the dogs dying from grand mal seizure, it was established that the data for the control groups from previous and contemporary experiments could be pooled. The change in hazard rates relative to controls resulting from exposure to the baseline radionuclide level was modest, 1.6 times for 239Pu (P = 0.033), 1.0(4) for 226Ra (P = 0.86), 1.9 for 228Ra (P = 0.035), 2.5 for 228Th (P less than 0.001), and 0.52 for 90Sr (P = 0.041). Bone tumor induction was clearly elevated in dogs injected with 239Pu and 228Th. When the effect of these bone tumors on survival

  1. Compositional variation and 226Ra-230Th model ages of axial lavas from the southern Mid-Atlantic Ridge, 8°48'S

    NASA Astrophysics Data System (ADS)

    Haase, K. M.; Brandl, P. A.; Devey, C. W.; Hauff, F.; Melchert, B.; Garbe-Schönberg, D.; Kokfelt, T. F.; Paulick, H.

    2016-01-01

    We present geological observations and geochemical data for the youngest volcanic features on the slow spreading Mid-Atlantic Ridge at 8°48'S that shows seismic evidence for a thickened crust and excess magma formation. Young lava flows with high sonar reflectivity cover about 14 km2 in the axial rift and were probably erupted from two axial volcanic ridges each of about 3 km in length. Three different lava units occur along an about 11 km long portion of the ridge, and lavas from the northern axial volcanic ridge differ from those of the southern axial volcanic ridge and surrounding lava flows. Basalts from the axial rift flanks and from a pillow mound within the young flows are more incompatible element depleted than those from the young volcanic field. Lavas from this volcanic area have 226Ra-230Th disequilibria model ages of 1000 and 4000 years whereas the older lavas from the rift flank and the pillow mound, but also some of the lava field, are older than 8000 years. Glasses from the northern and southern ends of the southern lava unit indicate up to 100°C cooler magma temperatures than in the center and increased assimilation of hydrothermally altered material. The compositional heterogeneity on a scale of 3 km suggests small magma batches rising vertically from the mantle to the surface without significant lateral flow and mixing. The observations on the 8°48'S lava field support the model of low-frequency eruptions from single ascending magma batches that has been developed for slow spreading ridges.

  2. Development of a neural network approach to characterise (226)Ra contamination at legacy sites using gamma-ray spectra taken from boreholes.

    PubMed

    Varley, Adam; Tyler, Andrew; Smith, Leslie; Dale, Paul

    2015-02-01

    There are a large number of sites across the UK and the rest of the world that are known to be contaminated with (226)Ra owing to historical industrial and military activities. At some sites, where there is a realistic risk of contact with the general public there is a demand for proficient risk assessments to be undertaken. One of the governing factors that influence such assessments is the geometric nature of contamination particularly if hazardous high activity point sources are present. Often this type of radioactive particle is encountered at depths beyond the capabilities of surface gamma-ray techniques and so intrusive borehole methods provide a more suitable approach. However, reliable spectral processing methods to investigate the properties of the waste for this type of measurement have yet to be developed since a number of issues must first be confronted including: representative calibration spectra, variations in background activity and counting uncertainty. Here a novel method is proposed to tackle this issue based upon the interrogation of characteristic Monte Carlo calibration spectra using a combination of Principal Component Analysis and Artificial Neural Networks. The technique demonstrated that it could reliably distinguish spectra that contained contributions from point sources from those of background or dissociated contamination (homogenously distributed). The potential of the method was demonstrated by interpretation of borehole spectra collected at the Dalgety Bay headland, Fife, Scotland. Predictions concurred with intrusive surveys despite the realisation of relatively large uncertainties on activity and depth estimates. To reduce this uncertainty, a larger background sample and better spatial coverage of cores were required, alongside a higher volume better resolution detector. PMID:25461525

  3. Cross-sections of the reaction 232Th(p,3n)230Pa for production of 230U for targeted alpha therapy.

    PubMed

    Morgenstern, Alfred; Apostolidis, Christos; Bruchertseifer, Frank; Capote, Roberto; Gouder, Thomas; Simonelli, Federica; Sin, Mihaela; Abbas, Kamel

    2008-10-01

    (230)U/(226)Th is a promising novel alpha-emitter system for application in targeted alpha therapy of cancer. The therapeutic nuclides can be produced by proton irradiation of natural (232)Th according to the reaction (232)Th(p,3n)(230)Pa, followed by subsequent beta decay of (230)Pa to (230)U. In this study, the experimental excitation function for the (232)Th(p,3n)(230)Pa reaction up to 34 MeV proton energy has been measured using the stacked-foil technique. The proton energies in the various foils were calculated with the SRIM 2003 code and gamma-ray spectrometry was used to measure the activities of the various radioisotopes produced. The measured cross-sections are in good agreement with selected literature values and with model calculations using the EMPIRE II code. The reaction (232)Th(p,3n)(230)Pa allows the production of carrier-free (230)U in clinically relevant levels. PMID:18374585

  4. Clay Mineral: Radiological Characterization

    NASA Astrophysics Data System (ADS)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  5. Natural radioactivity level in beach sand along the coast of Xiamen Island, China.

    PubMed

    Huang, Yingnan; Lu, Xinwei; Ding, Xiang; Feng, Tingting

    2015-02-15

    The activity concentration of (40)K, (232)Th and (226)Ra was determined in beach sand samples collected from Xiamen Island, China using gamma ray spectrometry. The activity concentrations of (40)K, (232)Th and (226)Ra in the beach sand range from 197.4 to 487.6, 6.5 to 41.4 and 7.9 to 25.7 Bq kg(-1) with the mean of 401.0, 11.3 and 14.1 Bq kg(-1), respectively, which are lower than the averages of Chinese soil and world soil. The radium equivalent activity values in all beach sand samples are lower than the recommended limit of 370 Bq kg(-1). The external hazard index values are less than unity. The outdoor air absorbed dose rate and the corresponding annual effective dose rate of beach sand investigated are lower than the worldwide average. PMID:25510548

  6. Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412).

    PubMed

    Pham, M K; van Beek, P; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gurriaran, R; Hanley, O; Harms, A V; Herrmann, J; Hult, M; Ikeuchi, Y; Ilchmann, C; Kanisch, G; Kis-Benedek, G; Kloster, M; Laubenstein, M; Llaurado, M; Mas, J L; Nakano, M; Nielsen, S P; Osvath, I; Povinec, P P; Rieth, U; Schikowski, J; Smedley, P A; Suplinska, M; Sýkora, I; Tarjan, S; Varga, B; Vasileva, E; Zalewska, T; Zhou, W

    2016-03-01

    The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training. PMID:26631455

  7. Natural radioactivity concentration of peanuts in Osmaniye-Turkey

    SciTech Connect

    Akkurt, Iskender; Guenoglu, Kadir; Mavi, Betuel; Kara, Ayhan

    2012-09-06

    The peanut is grown in Osmaniye where located in southern Turkey. Due to it is grown underground, the measurements of natural radioactivity of peanuts become important. For this reason some peanut samples have been collected from different places of Osmaniye and the measurements of natural activity concentrations for {sup 40}K, {sup 226}Ra and {sup 232}Th in some peanuts samples have been carried out using a NaI(Tl) gamma-ray spectrometer. Activity of {sup 40}K was measured from its intensive line at 1460 keV, for {sup 226}Ra activity peak from {sup 214}Bi at 1760 keV and {sup 232}Th activity, peak from {sup 208}Tl at energy of 2610 keV was used.

  8. Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters.

    PubMed

    Krmpotić, Matea; Rožmarić, Martina; Barišić, Delko

    2015-06-01

    Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring ((7)Be, (40)K, (232)Th, (226)Ra and (238)U), as well as anthropogenic (137)Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of (7)Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of (40)K did not vary significantly with season or location. (137)Cs activities were low, while (232)Th, (226)Ra and (238)U activities were mostly below the detection limit of performed gamma-spectrometric measurement. PMID:25794925

  9. Study of the violent collisions between {sup 63}Cu+{sup 232}Th at 35 MeV/nucleon

    SciTech Connect

    Cibor, J.; Majka, Z.; Kozik, T.; Staszel, P.; Sosin, Z.; Hagel, K.; Li, J.; Lou, L.; Tezkratt, R.; Utley, D.; Wada, R.; Xiao, B.; Natowitz, J.

    1997-01-01

    A study of the decay of hot and heavy composite nuclei produced in the violent collisions between {sup 63}Cu and {sup 232}Th at 35A MeV is presented. The measurement of fission fragment correlations indicates that {approximately} 70{percent} of the projectile linear momentum can be transferred to the fissioning system. Heavy reaction products were observed at a laboratory angle of {theta}=6{degree} in coincidence with neutrons, light charged particles, and intermediate mass fragments. The dynamical aspects of the collisions between the projectile and target nuclei were investigated using the computer code CHIMERA which is based upon the molecular dynamics concept. Asymptotic characteristics of the reaction products were confronted with results of calculations of the tandem CHIMERA plus GEMINI codes. The data and model comparisons show that a composite system of mass as high as 275 amu and with an excitation energy {approximately} 1 GeV is formed in the most violent collisions. Some of the heavy reaction remnants are located on the fragment mass versus velocity plane inside the area where the evaporation residues resulting from the decay of the hot composite system are expected. A high neutron multiplicity associated with these events indicates their origin in the most dissipative events. However, a low cross section for the production of these remnants and the close similarity of their characteristics to the fission fragments do not allow more conclusive statements. {copyright} {ital 1997} {ital The American Physical Society}

  10. Retardation of [sup 238]U and [sup 232]Th decay chain radionuclides in Long Island and Connecticut aquifers

    SciTech Connect

    Copenhaver, S.A.; Krishnaswami, S.; Turekian, K.K. ); Epler, N.; Cochran, J.K. )

    1993-02-01

    Knowledge of the ability of an aquifer to retard the groundwater transport of toxic or radioactive ions can be inferred from the analysis of groundwater for the radionuclides of the [sup 238]U- and [sup 232]Th-decay chains. Groundwaters of varying chemical composition were analyzed from wells in Long Island, New York, and Connecticut. Aquifer lithologies are arkose, quartz sandstone, granite, and glacial drift. Adsorption (k[sub 1]) and desorption (k[sub 2]) coefficients for Ra and Pb were calculated using [sup 222]Rn activity as a measure of the supply of other [alpha]-recoil nuclides. Laboratory tests of the validity of this assumption were made by measuring the flux of [sup 224]Ra and [sup 222]Rn from aquifer solids. The ratio k[sub 1]/k[sub 2] is the distribution coefficient, K, which is effective equal to R[sub f], the retardation factor. The average value of K for Ra is 6 [times] 10[sup 2] in Long Island aquifers and 5 [times] 10[sup 4] in Connecticut. The distribution coefficient for Pb is 10[sup 4] in Long Island and 10[sup 5] in Connecticut. Results from this and other studies reveal a strong dependence of retardation on pH, f[sub o[sub 2

  11. Timing of degassing and plagioclase growth in lavas erupted from Mount St. Helens, 2004-2005, from 210Po-210Pb-226Ra disequilibria: Chapter 37 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Reagan, Mark K.; Cooper, Kari M.; Pallister, John S.; Thornber, Carl R.; Wortel, Matthew

    2008-01-01

    Disequilibrium between 210Po, 210Pb, and 226Ra was measured on rocks and plagioclase mineral separates erupted during the first year of the ongoing eruption of Mount St. Helens. The purpose of this study was to monitor the volatile fluxing and crystal growth that occurred in the weeks, years, and decades leading up to eruption. Whole-rock samples were leached in dilute HCl to remove 210Po precipitated in open spaces. Before leaching, samples had variable initial (210Po) values, whereas after leaching, the groundmasses of nearly all juvenile samples were found to have had (210Po) ≈ 0 when they erupted. Thus, most samples degassed 210Po both before and after the magmas switched from open- to closed-system degassing. All juvenile samples have (210Pb)/(226Ra) ratios within 2 δ of equilibrium, suggesting that the magmas involved in the ongoing eruption did not have strong, persistent fluxes of 222Rn in or out of magmas during the decades and years leading to eruption. These equilibrium values also require a period of at least a century after magma generation and the last significant differentiation of the Mount St. Helens dacites. Despite this, the elevated (210Pb)/(226Ra) value measured in a plagioclase mineral separate from lava erupted in 2004 suggests that a significant proportion of this plagioclase grew within a few decades of eruption. The combined dataset suggests that for most 2004-5 lavas, the last stage of open-system degassing of the dacite magmas at Mount St. Helens is confined to the period between 1-2 years and 1-2 weeks before eruption, whereas plagioclase large enough to be included in the mineral separate grew around the time of the 1980s eruption or earlier.

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

    PubMed

    Duggal, Vikas; Rani, Asha; Mehra, Rohit; Ramola, R C

    2014-01-01

    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. PMID:23943368

  13. Measurement of radioactivity levels in soil in the Nile Delta and middle Egypt.

    PubMed

    Ibrahiem, N M; Abd el Ghani, A H; Shawky, S M; Ashraf, E M; Farouk, M A

    1993-06-01

    Concentrations of radionuclides in surface soil across the Nile Delta, the north coast of Egypt, and Middle Egypt have been measured using a hyperpure germanium spectrometer. The concentrations obtained for 40K, the 232Th series, and the 226Ra series are expressed in Bq kg-1 of dry weight, and the exposure rates are expressed in nGy h-1 of wet weight. The activity concentrations of 137Cs in soil are expressed in Bq m-2. PMID:8491618

  14. Environmental radioactivity assessment for Bayburt, Turkey.

    PubMed

    Kucukomeroglu, B; Kurnaz, A; Damla, N; Cevik, U; Celebi, N; Ataksor, B; Taskin, H

    2009-09-01

    This study assesses the results of environmental radioactivity measurements for Bayburt Province in the Eastern Black Sea area of Turkey. Using gamma-ray spectrometry, activity concentrations of the natural radionuclides (226)Ra, (232)Th and (40)K and a fission product (137)Cs were investigated in soil samples. The activity concentrations of (226)Ra, (232)Th and (40)K in various building materials such as sand, cement and marble and in drinking waters were determined. The activity concentrations vary from 16 to 54 Bq kg(-1) for (226)Ra, from 10 to 21 Bq kg(-1) for (232)Th and from 113 to 542 Bq kg(-1) for (40)K in building materials. The mean specific activity concentrations of (226)Ra, (232)Th and (40)K in drinking waters were 93, 30 and 504 mBq l(-1), respectively. The concentrations of gross alpha and beta radioactivity in drinking water samples collected from four different sampling stations have been determined. The results show that the gross alpha and beta activities are lower than the screening levels given by the World Health Organization (WHO), which are a maximum contaminant level of 0.5 Bq l(-1) and 1.0 Bq l(-1) gross alpha and beta radioactivity, respectively, in drinking water. Indoor radon measurements were made in 44 dwellings in Bayburt by using Cr-39 detectors. Radon concentrations in dwellings in Bayburt varied from 17 to 125 Bq m(-3) and the average value was 56 Bq m(-3). The results obtained in this study indicate that the region has a background radiation level that is within the typical natural range and shows no significant departures from other parts of the country. PMID:19690358

  15. Radioactivity levels and heavy metals in the urban soil of Central Serbia.

    PubMed

    Milenkovic, B; Stajic, J M; Gulan, Lj; Zeremski, T; Nikezic, D

    2015-11-01

    Radioactivity concentrations and heavy metal content were measured in soil samples collected from the area of Kragujevac, one of the largest cities in Serbia. The specific activities of (226)Ra, (232)Th, (40)K and (137)Cs in 30 samples were measured by gamma spectrometry using an HPGe semiconductor detector. The average values ± standard deviations were 33.5 ± 8.2, 50.3 ± 10.6, 425.8 ± 75.7 and 40.2 ± 26.3 Bq kg(-1), respectively. The activity concentrations of (226)Ra, (232)Th and (137)Cs have shown normal distribution. The annual effective doses, radium equivalent activities, external hazard indexes and excess lifetime cancer risk were also estimated. A RAD7 device was used for measuring radon exhalation rates from several samples with highest content of (226)Ra. The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were measured, as well as their EDTA extractable concentrations. Wide ranges of values were obtained, especially for Cr, Mn, Ni, Pb and Zn. The absence of normal distribution indicates anthropogenic origin of Cr, Ni, Pb and Zn. Correlations between radionuclide activities, heavy metal contents and physicochemical properties of analysed soil were determined by Spearman correlation coefficient. Strong positive correlation between (226)Ra and (232)Th was found. PMID:26087932

  16. [Comparative evaluation of early and long-term plant cell reactions under the combination of short-time and chronic impact of 232Th and Cd ].

    PubMed

    Evseeva, T I; Geras'kin, S A; Khramova, E S

    2003-01-01

    The short-time (30 hours) and chronic (30 days) 232Th and Cd combined effects on Tradescantia and Allium cepa plants were investigated. The 232Th ion concentration was equal to 0.18 mg/l and Cd ion--to 60 mg/l. The early response of both somatic and generative plant cells on Th and Cd combined action was shown to appear in synergic increase of cytogenetic damage frequency. The level of genotoxic and cytotoxic long-term effects turned out to be lower than of the additive one both under the chronic as under the short-time action. These similar in result responses occur on different biological organization levels: in the case of short-time action the effects observed are detected by the intracellular compensatory processes, and in the case of chronic action by the mass death of the most damaged buds in the inflorescence. PMID:12945185

  17. High-resolution photofission measurements in /sup 238/U and /sup 232/Th. Progress report, June 1, 1979-February 10, 1980. [5 to 12 MeV

    SciTech Connect

    Lancman, H.

    1980-02-01

    High-intensity proton beams have been used to generate gamma rays of well-defined and variable energy from the (p,..gamma..) reaction on a number of targets. Spectra of photofission fragments of /sup 238/U and /sup 232/Th have been measured at gamma ray energies from 5.8 to 11.5 MeV. The photofission cross sections have been determined and preliminary values of barrier parameters, derived by fitting the data to model predictions.

  18. Radioactivity levels in plant samples in Tulkarem district, Palestine and its impact on human health.

    PubMed

    Thabayneh, Kaleel M; Jazzar, Mohannad M

    2013-01-01

    The activity concentrations of naturally occurring radioactive materials such as (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were measured for 44 plant samples collected from different locations in the northwestern region of the West Bank, Palestine, using high-resolution gamma ray spectroscopy. The activity concentrations of radionuclides in the investigated plant samples ranged from 7.5 to 157.6 Bq kg(-1) for (226)Ra, 7.5 to 66.1 Bq kg(-1) for (238)U, 1.8 to 48.5 Bq kg(-1) for (232)Th, 14.3 to 1622 Bq kg(-1) for (40)K and <0.1 to 4.7 Bq kg(-1) for (137)Cs. The average values of these activities were 48.3, 26.5, 10.1, 288.0 and 2.2 Bq kg(-1), for (226)Ra, (238)U, (232)Th, (40)K and (137)Cs, respectively. The study presents the total gamma radiation dose rate assessed from natural radionuclides,(137)Cs and cosmic radiation, the dose rate of each radionuclide and the effective dose for all the samples. The radiological health implication to the population that may result from these doses is found to be low, except in few cases. The measurements have been taken as representing a baseline database of values of these radionuclides in the plants in the area. PMID:22798274

  19. A radiological survey of the Eğrigöz granitoid, Western Anatolia/Turkey.

    PubMed

    Canbaz Öztürk, B; Yaprak, G; Çam, N F; Candan, O

    2015-06-01

    A radiological survey of the granitoid areas throughout Western Anatolia was conducted during 2007-14. As a part of this radiological survey, this article presents results obtained from Eğrigöz pluton, which lies in the northeastern region of Western Anatolia. In the investigated area, the activity measurements of the natural gamma-emitting radionuclides ((226)Ra, (232)Th and (40)K) in the granitic rock samples and soils have been carried out by means of the NaI(Tl) gamma-ray spectrometry system. The activity concentrations of the relevant natural radionuclides in the granite samples appeared in the ranges as follows: (226)Ra, 28-95 Bq kg(-1); (232)Th, 50-122 Bq kg(-1) and (40)K, 782-1365 Bq kg(-1), while the typical ranges of the (226)Ra, (232)Th and (40)K activities in the soil samples were found to be 7-184, 11-174 and 149-1622 Bq kg(-1), respectively. Based on the available data, the radiation hazard parameters associated with the surveyed rocks/soils are calculated. The corresponding absorbed dose rates in air from all those radionuclides were always much lower than 200 nGy h(-1) and did not exceed the typical range of worldwide average values noted in the UNSCEAR (2000) report. Furthermore, the data are also used for the mapping of the surface soil activity of natural radionuclides and the corresponding gamma dose rates of the surveyed area. PMID:25979749

  20. Natural radioactivity measurements in Pahang State, Malaysia.

    PubMed

    Gabdo, Hamman Tukur; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Garba, Nuraddeen Nasiru; Sanusi, Mohamad

    2016-06-01

    This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176 ± 5 nGy h(-1). Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides (226)Ra, (232)Th and (40)K are 110 ± 3, 151 ± 5 and 542 ± 51 Bq kg(-1), respectively.(226)Ra and (232)Th concentrations were found to be three times the world average, while that of (40)K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for (226)Ra (215 ± 6 Bq kg(-1)), (232)Th (384 ± 12 Bq kg(-1)) and (40)K (1564 ± 153 Bq kg(-1)). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg(-1) and the unity value, respectively. PMID:26999725

  1. Radiological study of Mersing District, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; Alajerami, Yasser; Aliyu, Abubakar Sadiq; Bt Basri, Nor Afifah

    2013-04-01

    A potential site has been selected for a nuclear power plant (NPP) in Mersing District of Malaysia. This study aims at providing the base line data of this district for the first time, in line with the International Atomic Energy Agency (IAEA) for NPP sitting criteria. The mean dose rate, mean population weighted dose rate and annual effective dose are found to be 140 nGy h-1, 0.836 mSv y-1 and 0.857 mSv, respectively. A hyper Purity Germanium Detector (HPGe) is used in determining the activity concentrations of 232Th, 226Ra and 40K. The activity concentration ranges from 16±1 to 410±15 Bq kg-1 for 232Th, 17±1 to 271±8 Bq kg-1 for 226Ra and 13±3 to 1434±57 Bq kg-1 for 40K. In addition, a Low Background Alpha Beta Series 5 XLB Automatic was used in the determination of gross alpha and gross beta activity. The result ranges from 202±50 to 2325±466 Bq kg-1 for gross alpha and 164±17 to 2447±103 Bq kg-1 for gross beta. Contour maps were produced for isodose, activity concentration of 232Th, 226Ra, 40K, gross alpha and gross beta for the study area. The results are compared with UNSCEAR (2000).

  2. Natural radionuclide uptake by mosses in eastern Serbia in 2008-2013.

    PubMed

    Čučulović, Ana Č; Sabovljević, Marko; Čučulović, Rodoljub Č; Veselinović, Dragan

    2016-03-01

    The results of the study on natural radionuclide content in 102 samples of the moss species randomly collected in 2008- 2013 at 30 locations of eastern Serbia are presented in the paper. The activity concentration values of 238U, 226Ra, 232Th, 40K, and 7Be determined by gamma spectrometry were within the intervals: 238U (1.1-50) Bq kg(-1), 226Ra (1.1-41) Bq kg(-1), 232Th (1.4-28) Bq kg(-1), 40K (64-484) Bq kg(-1) and 7Be (88-227) Bq kg(-1), not standing out of the average data reported for this region. The distribution of the obtained data for 226Ra, 232Th, and 238U activity concentration in the analysed mosses has shown values up to 10 Bq kg(-1) with frequencies 47.1 %, 54.9 % and 48.0 %, respectively. The obtained activity concentration values of primordial 40K and cosmogenic radionuclide 7Be were up to 500 Bq kg(-1) and about 90 % of all the results for 7Be uptake by mosses were in the 200-250 Bq kg(-1) concentration range. PMID:27092637

  3. An evaluation of the natural radioactivity in Andaman beach sand samples of Thailand after the 2004 tsunami.

    PubMed

    Malain, D; Regan, P H; Bradley, D A; Matthews, M; Al-Sulaiti, H A; Santawamaitre, T

    2012-08-01

    Following the 2004 'Boxing day' tsunami, a determination has been made of the activity concentrations of (226)Ra, (232)Th and (40)K in beach sand samples which have been collected from various locations along the Andaman coast of the Thai peninsula. Use has been made of a HPGe detector-based, low-background gamma-ray counting system. The natural radioactivity levels of (226)Ra, (232)Th and (40)K measured from these samples was found to lie in the range 1.6-52.5, 0.3-73.9 and 2.8-1111.9Bq/kg respectively for the west coast and 3.5-83.1, 4.5-42.0, and 9.6-1376 Bq/kg respectively for the east coast. The radioactivity concentrations of (226)Ra, (232)Th and (40)K along the Andaman coast are comparable to that of the east coast, which was not exposed to the tsunami. The corresponding annual effective dose varies from 1.6-105.9 μSv/y with a mean value of 59.1 ± 0.3 μSv/y, significantly lower than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (2000). PMID:22728129

  4. Measurement of cross sections for the {sup 232}Th(P,4n){sup 229}Pa reaction at low proton energies

    SciTech Connect

    Jost, C. U.; Griswold, J. R.; Bruffey, S. H.; Mirzadeh, S.; Stracener, D. W.; Williams, C. L.

    2013-04-19

    The alpha-emitters {sup 225}Ac and {sup 213}Bi are of great interest for alpha-radioimmunotherapy which uses radioisotopes attached to cancer-seeking antibodies to efficiently treat various types of cancers. Both radioisotopes are daughters of the long-lived {sup 229}Th(t{sub 1/2} = 7880y). {sup 229}Th can be produced by proton irradiation of {sup 232}Th and {sup 230}Th, either directly or through production of isobars that beta-decay into {sup 229}Th. To obtain excitation functions, {sup 232}Th and {sup 230}Th have been irradiated at the On-Line Test Facility at the Holifield Radioactive Ion Beam Facility at ORNL. Benchmark tests conducted with Cu and Ni foils show very good agreement with literature results. The experiments with thorium targets were focused on the production of {sup 229}Pa and its daughter {sup 225}Ac from both {sup 232}Th and {sup 230}Th. Differential cross-sections for production of {sup 229}Pa and other Pa isotopes have been obtained.

  5. Environmental-Impact Assessment of Natural Radioactivity Around a Traditional Mining Area in Al-Ibedia, Sudan.

    PubMed

    Idriss, Hajo; Salih, Isam; Alaamer, Abdulaziz S; Saleh, Almuaiz; Abdelgali, M Y

    2016-05-01

    Recently, in the Sudan, traditional gold mining has been growing rapidly and has become a very attractive and popular economic activity. Mining activity is recognized as one of the sources of radioactivity contamination. Hence, the radioactivity concentration and radiological hazard due to exposure of radionuclides (226)Ra, (232)Th, and (40)K were evaluated. The measurements were performed using gamma-ray spectrometry with an NaI (Tl) detector. The results show that (226)Ra, (232)Th, and (40)K activity concentration ranged from 2.66 to 18.47, 9.20 to 51.87, and 0.17 to 419.77 Bq/kg with average values of 7.54 ± 4.91, 20.74 ± 11.29, and 111.87 ± 136.84 Bq/kg, respectively. In contrast, (222)Rn in soil, (222)Rn in air, and (226)Ra in vegetables along with radiation dose were computed and compared with the international recommended levels. Potential radiological effects to miners and the public due to (226)Ra, (232)Th, (40)K, and (222)Rn are insignificant. (226)Ra transferred to vegetables appears to be negligible compared with the allowable limit 1.0 mSv/year set by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average value of the annual gonadal dose equivalent (AGDE) is lower than the global average of 300 µSv/year (UNSCEAR 2000). However, some locations exhibit values >300 µSv/year. To the best of our knowledge, so far there seems to be no data regarding radioactivity monitoring in traditional mining areas in the Sudan. PMID:26979743

  6. 238U-230Th-226Ra disequilibria in dacite and plagioclase from the 2004-2005 eruption of Mount St. Helens: Chapter 36 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Cooper, Kari M.; Donnelly, Carrie T.

    2008-01-01

    230Th)/(232Th) measured for the 1980s reference suite. However, (230Th)/(232Th) for plagioclase separates for dome samples erupted during October and November 2004 are significantly different from corresponding whole-rock values, which suggests that a large fraction (>30 percent) of crystals in each sample are foreign to the host liquid. Furthermore, plagioclase in the two 2004 samples have U-series characteristics distinct from each other and from plagioclase in dacite erupted in 1982, indicating that (1) the current eruption must include a component of crystals (and potentially associated magma) that were not sampled by the 1980-86 eruption, and (2) dacite magmas erupted only a month apart in 2004 contain different populations of crystals, indicating that this foreign component is highly heterogeneous within the 2004-5 magma reservoir.

  7. Radioactivity of sand, groundwater and wild plants in northeast Sinai, Egypt.

    PubMed

    Ramadan, Khaled A; Seddeek, Mostafa K; Nijim, Abdelkareem; Sharshar, Taher; Badran, Hussein M

    2011-12-01

    The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among (238)U, (234)Th, and (226)Ra isotopes and low significant correlations between the concentrations of (238)U-series and (232)Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. The range of concentrations of (226)Ra,( 232)Th, and (40)K in water samples collected from five wells were<0.4-0.16,<0.4-0.13, and<0.15-1.62 Bq l(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h(-1). The Ra(eq) activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials. PMID:22092101

  8. Evaluation of natural radioactivity and its associated health hazard indices of a South Indian river.

    PubMed

    Krishnamoorthy, N; Mullainathan, S; Mehra, R; Chaparro, Marcos A E; Chaparro, Mauro A E

    2014-12-01

    The activity concentration of the natural radionuclides (226)Ra, (232)Th and (40)K was measured for sediment samples collected from thirty-three different locations along the Bharathapuzha river basin by using high-resolution gamma-ray spectrometry. The concentrations of the natural radionuclides were found to vary from location to location, and their mean values are 19.6, 82.87 and 19.44% higher than the worldwide mean values of (226)Ra, (232)Th and (40)K, respectively. The value of (232)Th was found to be higher than that of (226)Ra in 82% of the samples collected for this study. The calculated values of indoor gamma dose rate (DIN) ranged between 89.55 and 194.24 nGy h(-1), and the overall mean value is 63.2% higher than the recommended safe and criterion limit by UNSCEAR. The internal and external hazard indices (H(in) and H(ex)), the representative gamma index and alpha index (I(gamma) and I(alpha)), the annual gonad dose equivalent (AGDE) and the excess lifetime cancer risk (ELCR) were also calculated and compared with the international recommended values. Multivariate statistical analyses were also carried out to determine the relation between the natural radionuclides and various radiological parameters. PMID:24319106

  9. Measurement of the Total Kinetic Energy Release (TKE) in 232 Th(n,f) with En = 2.59 - 87.31 MeV

    NASA Astrophysics Data System (ADS)

    King, Jonathan; Yanez, Ricardo; Barrett, Jonathan; Loveland, Walter; Tovesson, Fredrik; Fotiades, Nick; Lee, Hye Young

    2015-04-01

    Experimental results for the Total Kinetic Energy Release (TKE) of 232 Th(n,f) with En = 2.59 - 87.31 MeV will be presented. The experiment was performed at the 15R beamline at the Weapons Neutron Research(WNR) facility at LANL-LANSCE. WNR provides a white spectrum of neutrons peaking at 2 MeV and reaching up to 800 MeV, with neutron energies being deduced from measurements of the neutron time of flight (TOF). A thin-backed 232 ThF4 target of 2 cm diameter with a thorium areal density of 178.9 μg/cm2 was placed between two arrays of Hammamatsu PIN diodes (active area 4 cm2 each). The beam was collimated to 1 cm diameter. The target was placed 45 degrees off of the beam axis, with the detectors at 60 degrees and 120 degrees from the beam axis. Over 25,000 fission fragment coincidence events were recorded, allowing for sixteen energy bins between 2.59 and 87.31 MeV. We believe that this will be the most comprehensive published measurement of the TKE for 232 Th(n,f) with En = 2.59 - 87.31 MeV. This work was supported in part by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the USDoE under Grant DE-FG06-97ER41026. This work has benefited from the use of the Los Alamos Neutron Science Center at the Los Alamos National Laboratory. This facility is funded by the USDoE under DOE Contract No. DE-AC52-06NA25396.

  10. Comparison of the (p,xn) cross sections from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons

    SciTech Connect

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured absolute cross sections for (p,xn) reactions (x ranges from 0 to 8) from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons at the Brookhaven AGS Linac injector. Chemical yields were determined by using /sup 239/Np and /sup 233/Pa as tracers. Yield patterns obtained in this work can be compared to the experimental results and theoretical calculations from earlier work, and they are consistent within the framework of intranuclear cascade followed by neutron evaporation and fission competition.

  11. Cost-based optimizations of power density and target-blanket modularity for {sup 232}Th/{sup 233}U-based ADEP

    SciTech Connect

    Krakowski, R.A.

    1995-07-01

    A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a {sup 232}Th/{sup 233}U fuel cycle and a molten-salt (LiF/BeF{sub 2}/ThF{sub 3}) fluid-fuel primary system. Simplified neutron-balance, accelerator, reactor-core, chemical-processing, and balance-of-plant models are combined parametrically with a simplified costing model. The main focus of this model is to examine trade offs related to fission power density, reactor-core modularity, {sup 233}U breeding rate, and fission product transmutation capacity.

  12. Long-term tissue distribution and steady state activity ratios of 232Th and its daughters in rats after intravascular injection of Thorotrast.

    PubMed

    Norimura, T; Tsuchiya, T; Hatakeyama, S; Yamamoto, H; Okajima, S

    1989-09-01

    To estimate the absorbed dose in the critical organs of Thorotrast patients, it is necessary to know not only the distribution and concentration of 232Th but also its daughter nuclides in the body. The present investigation was undertaken in order to clarify the long-term 232Th tissue distribution and steady state activity ratios between subsequent daughters in the critical tissues using about 30 Wister male rats, as a basis for estimating absorbed doses. The tissue distribution of thorium was examined by means of an autoradiography of the whole body and/or the gamma-ray spectrometry at various times during 2 to 24 months following injection. The concentrations of daughter nuclides in tissues were determined by repetitive gamma examination over a period from 1 hr to 35 days after being sacrificed. The data indicate (1) that approximately 90% of injected Thorotrast is retained in the body for a prolonged period, but about 50% of radium and 10% of radon produced from thorium are eliminated from the body, (2) that the mean steady state activity ratios of 224Ra and 212Pb to 228Th for liver are 0.56 and 0.28, and 0.54 and 0.16 for spleen, 0.58 and 0.82 for lungs, respectively, and (3) that the parent 228Th is translocated to the bone. PMID:2554457

  13. 230Th/232Th activity ratios as a chronological marker complementing 210Pb dating in an estuarine system affected by industrial releases.

    PubMed

    San Miguel, E G; Bolívar, J P; García-Tenorio, R; Martín, J E

    2001-01-01

    The main purpose of this research is to show the usefulness of the 230Th/232Th activity ratios as a chronological marker that can be helpful in the dating of sediment cores collected from an estuarine system located in the south west of Spain highly polluted by wastes from fertilizer plants. These wastes, being released for 30 years, and enriched in radionuclides from the uranium series including 210Pb, invalidate the application of the 210Pb dating technique in full extent to the sediment cores collected in this estuary. However, the evaluation and the interpretation of both 210Pb and 230Th/232Th profiles allows the determination of average sedimentation rates in different parts of the cores, contaminated and noncontaminated zone, that agree in the case analysed in this research. Through this approach, a confident chronology covering the last century, which is essential to analyse and reconstruct the historical evolution of other pollutants in this heavily contaminated system can be established. PMID:11291442

  14. Edaphic factors affecting the vertical distribution of radionuclides in the different soil types of Belgrade, Serbia.

    PubMed

    Dragović, Snežana; Gajić, Boško; Dragović, Ranko; Janković-Mandić, Ljiljana; Slavković-Beškoski, Latinka; Mihailović, Nevena; Momčilović, Milan; Ćujić, Mirjana

    2012-01-01

    The specific activities of natural radionuclides ((40)K, (226)Ra and (232)Th) and Chernobyl-derived (137)Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of (40)K, (226)Ra and (137)Cs with fine-grained soil fractions. Significant positive correlations were found between (137)Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of (137)Cs. The strong positive correlations between (226)Ra and (232)Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between (40)K and Cr, Ni, Pb and Zn and also between (137)Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems. PMID:22072061

  15. Environmental radionuclides in a coastal wetland of the Southern Laizhou Bay, China.

    PubMed

    Wang, Qidong; Song, Jinming; Li, Xuegang; Yuan, Huamao; Li, Ning; Cao, Lei

    2015-08-15

    The radioactivity concentration of (238)U, (232)Th, (226)Ra, (40)K, and (137)Cs in soil samples collected in a coastal wetland of the Southern Laizhou Bay, China were measured. Mean activity concentrations were 54.4±11.7, 57.9±9.7, 28.6±4.3, 542±21, and 10.2±2.9Bqkg(-1) dry weight for (238)U, (232)Th, (226)Ra, (40)K and (137)Cs, respectively. Statistical analyses suggested significant correlations between clay content and (40)K as well as (137)Cs. The radium equivalent activity, the absorbed dose rate in the air at 1m above the ground surface, and the external hazard index were calculated. The result showed that the radioactivity level in the wetland was in normal range. But sites along the river tended to have higher radiological hazard indexes. The vertical distributions of radionuclides in profiles illustrated some phenomena, such as vertical transport of (238)U, disequilibrium between (238)U and (226)Ra, and change in material sources. PMID:26028169

  16. Dynamics of melt generation beneath mid-ocean ridge axes: Theoretical analysis based on [sup 238]U-[sup 230]Th-[sup 226]Ra and [sup 235]U-[sup 231]Pa disequilibria

    SciTech Connect

    Zhenwei Qin )

    1993-04-01

    Although slow melting favors the generation of basaltic melt from a mantle matrix with large radioactive disequilibrium between two actinide nuclides (McKenzie, 1985a), it results in long residence time in a magma chamber, during which the disequilibrium may be removed. An equilibrium melting model modified after McKenzie (1985a) is presented here which suggests that, for a given actinide parent-daughter pair, there exists a specific melting rate at which disequilibrium between these two nuclides reaches its maximum. This melting rate depends on the decay constant of the daughter nuclide concerned and the magma chamber volume scaled to that of its source. For a given scaled chamber size, large radioactive disequilibrium between two actinide nuclides in basalts will be observed if the melting rate is such that the residence time of the magma in the chamber is comparable to the mean life of the daughter nuclide. With a chamber size 1% in volume of the melting source, the melting rates at which maximum disequilibrium in basalts is obtained are 10[sup [minus]7], 2 [times] 10[sup [minus]7], and 3 [times] 10[sup [minus]6] y[sup [minus]1], respectively for [sup 238]U-[sup 230]Th, [sup 235]U-[sup 231]Pa, and [sup 230]Th-[sup 226]Ra. This implies that, while large disequilibrium between [sup 238]U-[sup 230]Th and between [sup 235]U-[sup 231]Pa may occur together, large [sup 230]Th-[sup 226]Ra disequilibrium will not coexist with large [sup 238]U-[sup 230]Th disequilibrium, consistent with some observations. The active mantle melting zone which supplies melt to a ridge axis is inferred to be only about 10 km thick and 50 km wide. The fraction of melt present in such a mantle source at any time is about 0.01 and 0.04, respectively, if melting rate is 10[sup [minus]7] and 10[sup [minus]6] y[sup [minus]1]. The corresponding residence time of the residual melt in the matrix is 10[sup 5] and 4 [times] 10[sup 4] y. 27 refs., 3 figs.

  17. Mid-ocean ridge basalt generation along the slow-spreading, South Mid-Atlantic Ridge (5-11°S): Inferences from 238U-230Th-226Ra disequilibria

    NASA Astrophysics Data System (ADS)

    Turner, Simon; Kokfelt, Thomas; Hauff, Folkmar; Haase, Karsten; Lundstrom, Craig; Hoernle, Kaj; Yeo, Isobel; Devey, Colin

    2015-11-01

    U-series disequilibria have provided important constraints on the physical processes of partial melting that produce basaltic magma beneath mid-ocean ridges. Here we present the first 238U-230Th-226Ra isotope data for a suite of 83 basalts sampled between 5°S and 11°S along the South Mid-Atlantic Ridge. This section of the ridge can be divided into 5 segments (A0-A4) and the depths to the ridge axis span much of the global range, varying from 1429 to 4514 m. Previous work has also demonstrated that strong trace element and radiogenic isotope heterogeneity existed in the source regions of these basalts. Accordingly, this area provides an ideal location in which to investigate the effects of both inferred melt column length and recycled materials. 226Ra-230Th disequilibria indicate that the majority of the basalts are less than a few millennia old such that their 230Th values do not require any age correction. The U-Th isotope data span a significant range from secular equilibrium up to 32% 230Th excess, also similar to the global range, and vary from segment to segment. However, the (230Th/238U) ratios are not negatively correlated with axial depth and the samples with the largest 230Th excesses come from the deepest ridge segment (A1). Two sub-parallel and positively sloped arrays (for segments A0-2 and A3 and A4) between (230Th/238U) and Th/U ratios can be modelled in various ways as mixing between melts from peridotite and recycled mafic lithologies. Despite abundant evidence for source heterogeneity, there is no simple correlation between (230Th/238U) and radiogenic isotope ratios suggesting that at least some of the trace element and radiogenic isotope variability may have been imparted to the source regions >350 kyr prior to partial melting to produce the basalts. In our preferred model, the two (230Th/238U) versus Th/U arrays can be explained by mixing of melts from one or more recycled mafic lithologies with melts derived from chemically heterogeneous

  18. A comparison of the natural survival of beagle dogs injected intravenously with low levels of sup 239 Pu, sup 226 Ra, sup 228 Ra, sup 228 Th, or sup 90 Sr

    SciTech Connect

    Bruenger, F.W.; Miller, S.C.; Lloyd, R.D. )

    1991-06-01

    The natural survival, relative to properly chosen controls, of 26 beagle dogs injected once intravenously with an average of 0.58 +/- 0.04 kBq {sup 239}Pu/kg, 23 dogs injected with 2.31 +/- 0.43 kBq {sup 226}Ra/kg, 13 dogs injected with 1.84 +/- 0.26 kBq {sup 228}Ra/kg, 12 dogs injected with 0.56 +/- 0.030 kBq {sup 228}Th/kg, and 12 dogs injected with 21.13 +/- 1.74 kBq {sup 90}Sr/kg was evaluated statistically. The amounts of these radionuclides are related directly to the estimated maximum permissible body burdens for humans suggested in ICRP II (1959). They constitute a level of exposure that initially was assumed to cause no deleterious effects in dogs. This study had two objectives: (1) identification of homogeneous control groups against which to evaluate the survival of the irradiated groups and (2) comparison of the survival characteristics and estimation of mortality or hazard rate ratios for control dogs vs dogs injected with the baseline dosages given above. It was shown, by goodness-of-fit plots, that the Cox proportional hazards model was an appropriate method of analysis. Therefore, covariates that possibly could influence survival were tested for significance. Only the effects of grand mal seizure, which is caused in epileptic dogs by an external stimulus and can be fatal if untreated, were significant (P less than 0.0001). Consequently, in the final model, death from grand mal seizure was considered as accidental. After censoring the dogs dying from grand mal seizure, it was established that the data for the control groups from previous and contemporary experiments could be pooled. The change in hazard rates relative to controls resulting from exposure to the baseline radionuclide level was modest, 1.6 times for {sup 239}Pu (P = 0.033), 1.0(4) for {sup 226}Ra (P = 0.86), 1.9 for {sup 228}Ra (P = 0.035), 2.5 for {sup 228}Th (P less than 0.001), and 0.52 for {sup 90}Sr (P = 0.041).

  19. Measurement of Fragment Mass Yields in Neutron-Induced Fission of 232TH and 238U at 33, 45 and 60 Mev

    NASA Astrophysics Data System (ADS)

    Simutkin, V. D.; Pomp, S.; Blomgren, J.; Österlund, M.; Andersson, P.; Bevilacqua, R.; Ryzhov, I. V.; Tutin, G. A.; Khlopin, V. G.; Onegin, M. S.; Vaishnene, L. A.; Meulders, J. P.; Prieels, R.

    2011-10-01

    Over the past years, a significant effort has been devoted to measurements of neutron-induced fission cross-sections at intermediate energies but there is a lack of experimental data on fission yields. Here we describe recent measurements of pre-neutron emission fragment mass distributions from intermediate energy neutron-induced fission of 232Th and 238U. The measurements have been done at the quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE and neutron peak energies at 32.8, 45.3 and 59.9 MeV. A multi-section Frisch-gridded ionization chamber was used as a fission fragment detector. The measurement results are compared with available experimental data. Some TALYS code modifications done to describe the experimental results are discussed.

  20. Delayed neutron and delayed photon characteristics from photofission of 232Th, 235,238U, and 237Np with endpoint Bremsstrahlung photons in the giant dipole resonance region

    NASA Astrophysics Data System (ADS)

    Doré, D.; Dighe, P. M.; Berthoumieux, E.; Laborie, J.-M.; Ledoux, X.; Macary, V.; Panebianco, S.; Ridikas, D.

    2009-10-01

    A renewed interest in photonuclear reactions was stimulated by applications as radioactive ion beam production, irradiation stations by high energy photons, shielding of electron accelerators, etc. Today, a particular attention is paid to the non-destructive characterization of waste barrels and the detection of nuclear materials, both based on photofission process and the associated delayed neutron (DN) and delayed photon (DP) emissions. The need of accurate and complete data for DN and DP yields and time characteristics of actinides was the motivation for an experimental campaign, started in 2004. In this paper, the experimental setup and the data analysis method will be presented and the modeling work will be described. Experimental results for DN and DP characteristics will be compared to calculations in the case of photofission of 232Th, 235,238U, and 237Np.

  1. Giant resonance for the actinide nuclei: Photoneutron and photofission cross sections for /sup 235/U, /sup 236/U, /sup 238/U, and /sup 232/Th

    SciTech Connect

    Caldwell, J.T.; Dowdy, E.J.; Berman, B.L.; Alvarez, R.A.; Meyer, P.

    1980-04-01

    The photoneutron cross sections sigma (..gamma..,n) and sigma (..gamma..,2n), and total photofission cross sections sigma (..gamma..,F) have been measured for /sup 235/U, /sup 236/U, /sup 238/U, and /sup 232/Th from threshold to 18.3 MeV using monoenergetic photons from the annihilation in flight of fast positrons and neutron-multiplicity detection in an efficient 4..pi.. neutron detector. Use of the ring-ratio technique allowed both the average photofission neutron energy for each nucleus to be obtained as a function of photon energy and, for /sup 236/U and /sup 238/U, the determination of the partial cross sections for first-chance sigma (..gamma.., f ) and second-chance sigma (..gamma..,n f ) photofission as well. Information extracted from the data includes integrated cross sections and their moments, giant-resonance parameters, deformation and radius parameters, and relative and absolute neutron and fission probabilities.

  2. Separation and quantification of 238U, 232Th and rare earths in monazite samples by ion chromatography coupled with on-line flow scintillation detector.

    PubMed

    Borai, E H; Mady, A S

    2002-10-01

    An alternative procedure has been described for efficient separation and quantitative determination of uranium (U), thorium (Th) and rare earth elements (REEs) in monazite mineral by high performance ion chromatographic system (IC). Different variables affecting the distribution coefficient, the retention and hence separation efficiency such as eluent flow rate and concentrations of HCI and ammonium sulfate (NH4)2SO4 containing the mobile phase were studied. The developed separation protocol of U, Th and REEs was optimized using an Ion Pac CS5 separation column followed by post-column derivatization reaction with Arsenaso III and UV-VIS spectrophotometric detection. Comparative evaluation of U, Th and REEs concentration in monazite mineral was demonstrated using two different on-line detection modes including flow through cell scintillation detector (FSD) and UV-VIS spectrophotometer. Response of the FSD was found to be linear over the full range of activities investigated (4-100 Bq). The lower limits of detection (LLD) for the investigated radionuclides were 3.0+0.1 Bq for 238U and 6.0 +/- 0.1 Bq for 232Th. The detection of 238U and 232Th by FSD shows good agreement with the corresponding determination by UV-VIS spectrophotometer. The content of ThO2 and U3O8 in monazite sample were found to be 4.7 +/- 0.1% and 0.42 +/- 0.04% using UV-VIS detector and 4.3 +/- 0.1% and 0.45 +/- 0.1% using FSD, respectively. PMID:12361323

  3. Porosity of the melting zone and variations in the solid mantle upwelling rate beneath Hawaii: Inferences from {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria

    SciTech Connect

    Sims, K.W.W.; DePaolo, D.J.; Murrell, M.T.; Baldridge, W.S.; Goldstein, S.; Clague, D.; Jull, M.

    1999-12-01

    Measurements of {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria in a suite of tholeiitic-to-basanitic lavas provide estimates of porosity, solid mantle upwelling rate and melt transport times beneath Hawaii. The observation that ({sup 230}Th/{sup 238}U) {gt} 1 indicates that garnet is required as a residual phase in the magma sources for all of the lavas. Both chromatographic porous flow and dynamic melting of a garnet peridotite source can adequately explain the combined U-Th-Ra and U-Pa data for these Hawaiian basalts. For chromatographic porous flow, the calculated maximum porosity in the melting zone ranges from 0.3--3% for tholeiites and 0.1--1% for alkali basalts and basanites, and solid mantle upwelling rates range from 40 to 100 cm/yr for tholeiites and from 1 to 3 cm/yr for basanites. For dynamic melting, the escape or threshold porosity is 0.5--2% for tholeiites and 0.1--0.8% for alkali basalts and basanites, and solid mantle upwelling rates range from 10 to 30 cm/yr for tholeiites and from 0.1 to 1 cm/yr for basanites. Assuming a constant melt productivity, calculated total melt fractions range from 15% for the tholeiitic basalts to 3% for alkali basalts and basanites.

  4. Radioactivity levels and radiological hazard indices at the Saudi coastline of the Gulf of Aqaba

    NASA Astrophysics Data System (ADS)

    Al-Trabulsy, H. A.; Khater, A. E. M.; Habbani, F. I.

    2011-03-01

    The coast of the Gulf of Aqaba is subjected to several sources of pollution due to several activities occurring at the coastal area. The activities vary between industrial, tourist and other development aspects at the Jordanian coastline of the Gulf of Aqaba. Phosphate industry has been considered a major source polluting the marine environment. According to official reports, 4-7 million tons of raw phosphate is exported through the Gulf of Aqaba. During transportation and loading, a small proportion of this enters the waters of the Gulf. Phosphate dust has also been considered another source of nutrients loading to the Gulf. 19 sediment samples were collected along the Saudi Gulf coastline, from the Saudi-Jordan border down to the end of the Gulf at Tiran Strait. Measurements of the activity concentrations of 226Ra, 232Th, 40K and 137Cs in Bq/kg (in dry weight) of the collected samples were carried out using gamma-ray spectrometry based on a highly pure germanium coaxial detector (HPGe). The concentrations of 238U and 232Th were also determined using ICP-MS technique. The average specific activities for 226Ra, 232Th, 40K and 137Cs were found to be 11.4±1.5, 22.5±3.7, 641.1±61.3 and 3.5±0.7 Bq/kg, respectively. The results show that the mean activity of 226Ra and 232Th is lower than the world average of 25 Bq/kg for both of them, whereas the mean value for 40K is about double the world average of 370 Bq/kg. The presence of 137Cs in the analyzed samples is low in most locations. The mean concentrations of 238U and 232Th in the study area are 1.2 and 5.4 mg/kg, respectively, and the ratio 238U/ 232Th is 0.2, which is lower than the global ratio of 0.3. The ratio of 226Ra/ 228Ra was found to decrease southwards in the direction of Tiran Strait, away from the phosphate industry in Jordan. Mean values for radium equivalent, absorbed dose, annual effective dose, external and internal hazard index and representative level index were determined as: 92.9 Bq/kg, 45.6 n

  5. Transfer Rates of 238U and 232Th for E. globulus, A. mearnsii, H. filipendula and Hazardous Effects of the Usage of Medicinal Plants From Around Gold Mine Dump Environs

    PubMed Central

    Tshivhase, Victor M.; Njinga, Raymond L.; Mathuthu, Manny; Dlamini, Thulani C.

    2015-01-01

    Medicinal plant consumption can be a source of human exposure to radioactive elements such as 238U and 232Th, which can lead to internal radiation doses. The uptake of 238U and 232Th from soils to the leaf samples of three different medicinal plant species (Eucalyptus globulus, Acacia mearnsii and Hyparrhenia filipendula) from the purlieu of the Princess gold mine dump, an abandoned contaminated tailings storage site (TSS), located at longitude 27°55′00″E and latitude 26°09′30″S in Davidsonville (Roodepoort, west of Johannesburg, South Africa) was measured. This was done using ICP-MS spectrometry and substantial differences were observed in the soil-plant transfer factor (TF) values between these radionuclides. The plant species E. globulus exhibited the highest uptake of 238U, with an average TF of 3.97, while that of H. filipendula was 0.01 and the lowest TF of 0.15 × 10−2 was measured for A. mearnsii. However, in the case of 232Th, the highest average TF was observed for A. mearnsii (0.29), followed by E. globulus (0.10) and lowest was measured for H. filipendula (0.27 × 10−2). The ratio of TF average value i.e., 238U to 232Th in the soil-plant leaves was 38.05 for E. globulus, 0.01 for A. mearnsii and 4.38 for H. filipendula. PMID:26690462

  6. Significant radioactive contamination of soil around a coal-fired thermal power plant.

    PubMed

    Papp, Z; Dezso, Z; Daróczy, S

    2002-01-01

    Soil samples were collected around a coal-fired power plant from 81 different locations. Brown coal, unusually rich in uranium, is burnt in this plant that lies inside the confines of a small industrial town and has been operational since 1943. Activity concentrations of the radionuclides 238U, 226Ra, 232Th, 137Cs and 40K were determined in the samples. Considerably elevated concentrations of 238U and 226Ra have been found in most samples collected within the inhabited area. Concentrations of 235U and 226Ra in soil decreased regularly with increasing depth at many locations, which can be explained by fly-ash fallout. Concentrations of 235U and 226Ra in the top (0-5 cm depth) layer of soil in public areas inside the town are 4.7 times higher, on average, than those in the uncontaminated deeper layers, which means there is about 108 Bq kg(-1) surplus activity concentration above the geological background. A high emanation rate of 222Rn from the contaminated soil layers and significant disequilibrium between 238U and 226Ra activities in some kinds of samples have been found. PMID:11900206

  7. Evaluation of naturally occurring radioactive materials (NORM) in the South Western oil wells of Iran.

    PubMed

    Khodashenas, Alireza; Roayaei, Emad; Abtahi, Seyed Mojtaba; Ardalani, Elham

    2012-07-01

    An investigation was carried out to find out the concentration of Naturally Occurring Radioactive Materials (NORMs) in an oil production unit, an evaporation pond, and a drilling site in the Khuzestan province, in south west Iran the 4th largest oil producing country in the world. The nuclides (232)Th and (40)K were determined in soil samples and (226)Ra was analyzed in both soil and water. The (232)Th ranged between 8.7 and 403 Bq kg(-1), while the minimum concentration for (40)K was much larger, i.e. 82 Bq kg(-1) and its maximum concentration was 815 Bq kg(-1). Soil samples indicated very low concentrations of (226)Ra, typically between 10.6 and 42.1 Bq kg(-1) with some exceptions of 282, 602, and even 1480 Bq kg(-1). Also, the range for (226)Ra in water was less from 0.1 to a maximum 30.3 Bq L(-1). Results show that on average, NORM concentrations in these areas are lower in comparison with the usual concentration levels in typical oil and gas fields, but despite this fact, necessary measures have to be taken in order to minimize the environmental impact of radioactive materials. PMID:22321893

  8. Dissolved and particulate 230Th-232Th in the Central Equatorial Pacific Ocean: Evidence for far-field transport of the East Pacific Rise hydrothermal plume

    NASA Astrophysics Data System (ADS)

    Lopez, Grecia I.; Marcantonio, Franco; Lyle, Mitch; Lynch-Stieglitz, Jean

    2015-12-01

    We assess the distribution of 230Th and 232Th along a latitudinal gradient in the Central Equatorial Pacific Ocean (˜155°W-159°W) at two sites: 8°N and the equator. The dissolved 230Th concentration profile at 8°N increases nearly linearly from the surface to 2000 m, exhibiting behavior consistent with thermodynamic reversible scavenging. However, from 2000 m to 3000 m, the dissolved 230Th concentrations exhibit little change, before increasing slightly from 3000 m to the bottom. At this site dissolved 230Th concentrations range from 1.1 fg/kg at 100 m to 55.2 fg/kg at 4600 m. At the equator, dissolved 230Th concentrations are slightly lower, and range from undetectable at 25 m to 19.1 fg/kg at 3038 m. The pattern in the dissolved 230Th concentration profile at the equator is indistinguishable from that at 8°N. The mid-depth-water deviation from equilibrium reversible scavenging between 2 and 3 km in the 230Th profiles (lower concentrations than expected) at both sites occurs in the interval of the water column that is consistent with an interval that has high concentrations of 3He and dissolved Fe at other nearby sites. This 3He- and Fe-rich signal has been traced to hydrothermal plumes from the East Pacific Rise, thousands of kilometers away. We hypothesize that the lower concentrations of 230Th in mid-depth waters of the Central Equatorial Pacific are a result of a 5000-km transit of waters that have had their 230Th scavenged by Fe-Mn particulates close to the EPR. Oceanic residence times of thorium combined with dissolved 232Th concentrations suggest dust fluxes of about ˜ 0.5- 0.6 gm-2yr-1 to the sea surface. These fluxes are in agreement with other empirical studies in the Pacific, but are higher than those suggested by global atmospheric circulation models.

  9. Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash.

    PubMed

    Sahu, S K; Tiwari, M; Bhangare, R C; Pandit, G G

    2014-12-01

    Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for (210)Po using alpha spectrometry and for natural U, (226)Ra, (232)Th and (40)K by an HPGe γ-ray spectrometer. (210)Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of (238)U, (226)Ra, (232)Th, (40)K in fly ash were 38.5-101 (78.1), 60-105.7 (79), 20-125 (61.7) and 43.6-200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. (210)Po showed the largest size dependence with its concentration favoring the smaller particle size while (232)Th showed least size dependence. (238)U and (226)Ra showed behavior intermediate to that of (210)Po and (232)Th. Also the correlation between sulfur content of the feed coal and activity of (210)Po was investigated. Increased sulfur content in feed coal enhanced enrichment of (210)Po in ash. PMID:24813148

  10. Clay Mineral: Radiological Characterization

    SciTech Connect

    Cotomacio, J. G.; Silva, P. S. C.; Mazzilli, B. P

    2008-08-07

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and {sup 40}K in these clay minerals.The objective of this work is to determine the concentrations of {sup 238}U, {sup 232}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay.Measurement for the determination of {sup 238}U and {sup 232}Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906{+-}340 Bq kg{sup -1} for {sup 40}K, 40{+-}9 Bq kg{sup -1} for {sup 226}Ra, 75{+-}9 Bq kg{sup -1} for {sup 228}Ra, 197{+-}38 Bq kg{sup -1} for {sup 210}Pb, 51{+-}26 Bq kg{sup -1} for {sup 238}U and 55{+-}24 Bq kg{sup -1} for {sup 232}Th, considering both kinds of clay.

  11. Experimental Neutron-induced Fission Fragment Mass Yields of 232Th and 238U at Energies from 10 to 33 Me

    NASA Astrophysics Data System (ADS)

    Simutkin, V. D.; Pomp, S.; Blomgren, J.; Österlund, M.; Bevilacqua, R.; Andersson, P.; Ryzhov, I. V.; Tutin, G. A.; Yavshits, S. G.; Vaishnene, L. A.; Onegin, M. S.; Meulders, J. P.; Prieels, R.

    2014-05-01

    Development of nuclear energy applications requires data for neutron-induced reactions for actinides in a wide neutron energy range. Here we describe measurements of pre-neutron emission fission fragment mass yields of 232Th and 238U at incident neutron energies from 10 to 33 MeV. The measurements were done at the quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE; a multi-section twin Frisch-gridded ionization chamber was used to detect fission fragments. For the peak neutron energies at 33, 45 and 60 MeV, the details of the data analysis and the experimental results were published in Ref. [I.V. Ryzhov, S.G. Yavshits, G.A. Tutin et al., Phys. Rev. C 83, 054603 (2011)]. In this work we present data analysis in the low-energy tail of the neutron energy spectra. The preliminary measurement results are compared with available experimental data and theoretical predictions.

  12. Influence of different data tables on neutron induced reactions in quasi-infinite 238U and 232Th targets irradiated by protons with relativistic energy

    NASA Astrophysics Data System (ADS)

    Zhivkov, P.; Stoyanov, Ch; Tyutyunnikov, S.; Furman, W.

    2016-06-01

    The last decade saw the emergence of various theoretical analysis and developments of ADS (Accelerator Driving System). Different transport codes, nuclear models and nuclear cross sections have been used to predict and estimate the properties of ADS. The energy of the proton beam is supposed to range between 1 and 1.5 GeV, but some analyses suggest higher energy - up to 10 GeV. The recent papers examine the influence of the nuclear models on neutron induced reactions (n,f), (n,g), (n,xn), (n,el.) and (n,inel.). The experimental set-ups and the presumable ADS constructions consist of thousands of segments and details for example project Myrrha, Belgum [1]. The calculation of the above reactions depends on the neutron spectrum in each segment. There is a considerable difference in the size of these segments in ADS, which makes the estimation of the influence of the nuclear models and the cross sections on the integral number of neutron induced reactions more difficult. This article considers the influence of different cross section data tables on neutron induced reactions in 238U or 232Th targets. One nuclear model describing the high energy part of the nuclear interaction and various cross section data tagble (ENDF, ENDL, TENDL2014 and etc.) are used. All particles generated in the nuclear interaction process deposit their energy in the target volume. MCNP 6.1 transport code was used.

  13. Neutron Radiative Capture Cross Section of {sup 232}Th in the Energy Range from 0.06 to 2 MeV

    SciTech Connect

    Karamanis, D.; Petit, M.; Andriamonje, S.; Barreau, G.; Bercion, M.; Billebaud, A.; Blank, B.; Czajkowski, S.; Moral, R. del; Giovinazzo, J.; Lacoste, V.; Marchand, C.; Perrot, L.; Pravikoff, M.; Thomas, J.C.

    2001-11-15

    The neutron capture cross section of {sup 232}Th has been measured relative to {sigma}(n, {gamma}) for {sup 197}Au and {sigma}(n,f) for {sup 235}U in the energy range from 60 keV to 2 MeV. Neutrons were produced by the {sup 7}Li(p,n) and T(p,n) reactions at the 4-MV Van de Graaff Accelerator of CEN Bordeaux-Gradignan. The activation technique was used, and the cross section was measured relative to the {sup 197}Au(n,{gamma}) standard cross section up to 1 MeV. The characteristic gamma lines of the product nuclei {sup 233}Pa and {sup 198}Au were measured with a 40% high-purity germanium detector. Above this energy, the reaction {sup 235}U(n,f) was also used as a second standard, and the fission fragments were detected with a photovoltaic cell. The results, after applying the appropriate corrections, indicate that the cross sections are close to the JENDL-3 database values up to 800 keV and over 1.4 MeV. For energies in the intermediate range, our values are slightly lower than those from all the libraries.

  14. Radiological investigation of lignite ash. The case of the West Macedonia Lignite Center (Greece)

    SciTech Connect

    Tsikritzis, L.I.; Fotakis, M.; Tzimkas, N.; Tsikritzi, R.; Trikoilidou, E.; Kolovos, N.

    2009-07-01

    This article investigates the natural radioactivity of 26 ash samples, laboratory produced from lignite samples collected in the West Macedonia Lignite Center in Northern Greece. The activity concentrations of {sup 40}K, {sup 235}U, {sup 238}U, {sup 226}Ra, {sup 228}Ra, and 232Th were measured by spectroscopy and found four to five times higher than those in the original lignite samples. The radionuclides transfer factors depend on the characteristics of the combustion process and were found higher for {sup 232}Th, {sup 228}Ra, and 40K, because of their closer affinity with the inorganic fraction of the lignite. Compared with other results found in the published literature, the studied ash has relatively high content in radioactivity, but the resulting radiation dose from the radionuclide emissions in the West Macedonia Lignite Center do not contribute significantly to the total effective dose.

  15. High-spin structure in 40K

    NASA Astrophysics Data System (ADS)

    Söderström, P.-A.; Recchia, F.; Nyberg, J.; Gadea, A.; Lenzi, S. M.; Poves, A.; Ataç, A.; Aydin, S.; Bazzacco, D.; Bednarczyk, P.; Bellato, M.; Birkenbach, B.; Bortolato, D.; Boston, A. J.; Boston, H. C.; Bruyneel, B.; Bucurescu, D.; Calore, E.; Cederwall, B.; Charles, L.; Chavas, J.; Colosimo, S.; Crespi, F. C. L.; Cullen, D. M.; de Angelis, G.; Désesquelles, P.; Dosme, N.; Duchêne, G.; Eberth, J.; Farnea, E.; Filmer, F.; Görgen, A.; Gottardo, A.; Grębosz, J.; Gulmini, M.; Hess, H.; Hughes, T. A.; Jaworski, G.; Jolie, J.; Joshi, P.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Karolak, M.; Kempley, R. S.; Khaplanov, A.; Korten, W.; Ljungvall, J.; Lunardi, S.; Maj, A.; Maron, G.; Męczyński, W.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Molini, P.; Napoli, D. R.; Nolan, P. J.; Norman, M.; Obertelli, A.; Podolyak, Zs.; Pullia, A.; Quintana, B.; Redon, N.; Regan, P. H.; Reiter, P.; Robinson, A. P.; Şahin, E.; Simpson, J.; Salsac, M. D.; Smith, J. F.; Stézowski, O.; Theisen, Ch.; Tonev, D.; Unsworth, C.; Ur, C. A.; Valiente-Dobón, J. J.; Wiens, A.

    2012-11-01

    High-spin states of 40K have been populated in the fusion-evaporation reaction 12C(30Si,np)40K and studied by means of γ-ray spectroscopy techniques using one triple-cluster detector of the Advanced Gamma Tracking Array at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. Several states with excitation energy up to 8 MeV and spin up to 10- have been discovered. These states are discussed in terms of J=3 and T=0 neutron-proton hole pairs. Shell-model calculations in a large model space have shown good agreement with the experimental data for most of the energy levels. The evolution of the structure of this nucleus is here studied as a function of excitation energy and angular momentum.

  16. Study of secondary neutron interactions with 232Th, 129I, and 127I nuclei with the uranium assembly “QUINTA” at 2, 4, and 8GeV deuteron beams of the JINR Nuclotron accelerator

    DOE PAGESBeta

    Adam, J.; Chilap, V. V.; Furman, V. I.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Stegailov, V. I.; Suchopar, M.; Tsoupko-Sitnikov, V. M.; et al

    2015-11-04

    The natural uranium assembly, “QUINTA”, was irradiated with 2, 4, and 8 GeV deuterons. The 232Th, 127I, and 129I samples have been exposed to secondary neutrons produced in the assembly at a 20-cm radial distance from the deuteron beam axis. The spectra of gamma rays emitted by the activated 232Th, 127I, and 129I samples have been analyzed and several tens of product nuclei have been identified. For each of those products, neutron-induced reaction rates have been determined. The transmutation power for the 129I samples is estimated. Furthermore, experimental results were compared to those calculated with well-known stochastic and deterministic codes.

  17. Measurement of 238U and 232Th in Petrol, Gas-oil and Lubricant Samples by Using Nuclear Track Detectors and Resulting Radiation Doses to the Skin of Mechanic Workers.

    PubMed

    Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

    2015-10-01

    Workers in repair shops of vehicles (cars, buses, truck, etc.) clean carburetors, check fuel distribution, and perform oil changes and greasing. To explore the exposure pathway of (238)U and (232)Th and its decay products to the skin of mechanic workers, these radionuclides were measured inside petrol, gas-oil, and lubricant material samples by means of CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs), and corresponding annual committed equivalent doses to skin were determined. The maximum total equivalent effective dose to skin due to the (238)U and (232)Th series from the application of different petrol, gas-oil, and lubricant samples by mechanic workers was found equal to 1.2 mSv y(-1) cm(-2). PMID:26313584

  18. The applicability of MGA method for depleted and natural uranium isotopic analysis in the presence of actinides (232Th, 237Np, 233Pa and 241Am).

    PubMed

    Yücel, Haluk

    2007-11-01

    The multi-group analysis (MGA) method for the determination of uranium isotopic abundances in depleted uranium (DU) and natural uranium (NU) samples is applied in this study. A set of non-destructive gamma-ray measurements of DU and NU samples were performed using a planar Ge detector. The relative abundances of 235U and 238U isotopes were compared with the declared values of the standards. The relative abundance for 235U obtained by MGA for a "clean" DU or NU sample with a content of uranium>1wt% is determined with an accuracy of about +/-5%. However, when several actinides such as 232Th, 237Np, 233Pa and 241Am are present along with uranium isotopes simulating "dirty" DU or NU, it has been observed that MGA method gives erroneous results. The 235U abundance results for the samples were 6-25 times higher than the declared values in the presence of above-mentioned actinides, since MGA is utilized the X-ray and gamma-ray peaks in the 80-130 keV energy region, covering XKalpha and XKbeta regions. After the least-squares fitting of the spectra, it is found that the increases in the intensities of the X-ray and gamma-ray peaks of uranium are remarkably larger in the complex 80-130 keV region. On the other hand, it is observed that the interferences of the actinide peaks are relatively less dominant in the higher gamma-ray region of 130-300 keV. The results imply the need for dirty DU and NU samples that the MGA method should utilize the higher energy gamma-rays (up to 1001 keV of (234m)Pa) combined with lower energies of the spectra, which may be collected in a two detector mode (a planar Ge and a high efficient coaxial Ge). PMID:17606378

  19. A precise 232Th-208Pb chronology of fine-grained monazite: Age of the Bayan Obo REE-Fe-Nb ore deposit, China

    USGS Publications Warehouse

    Wang, Jingyuan; Tatsumoto, M.; Li, X.; Premo, W.R.; Chao, E.C.T.

    1994-01-01

    We have obtained precise Th-Pb internal isochron ages on monazite and bastnaesite for the world's largest known rare earth elements (REE)-Fe-Nb ore deposit, the Bayan Obo of Inner Mongolia, China. The monazite samples, collected from the carbonate-hosted ore zone, contain extremely small amounts of uranium (less than 10 ppm) but up to 0.7% ThO2. Previous estimates of the age of mineralization ranged from 1.8 to 0.255 Ga. Magnetic fractions of monazite and bastnaesite samples (<60-??m size) showed large ranges in 232Th 204Pb values (900-400,000) and provided precise Th-Pb internal isochron ages for paragenetic monazite mineralization ranging from 555 to 398 Ma within a few percent error (0.8% for two samples). These results are the first indication that REE mineralization within the giant Bayan Obo ore deposit occurred over a long period of time. The initial lead isotopic compositions (low 206Pb 204Pb and high 208Pb 204Pb) and large negative ??{lunate}Nd values for Bayan Obo ore minerals indicate that the main source(s) for the ores was the lower crust which was depleted in uranium, but enriched in thorium and light rare earth elements for a long period of time. Zircon from a quartz monzonite, located 50 km south of the ore complex and thought to be related to Caledonian subduction, gave an age of 451 Ma, within the range of monazite ages. Textural relations together with the mineral ages favor an epigenetic rather than a syngenetic origin for the orebodies. REE mineralization started around 555 Ma (disseminated monazite in the West, the Main, and south of the East Orebody), but the main mineralization (banded ores) was related to the Caledonian subduction event ca. 474-400 Ma. ?? 1994.

  20. Allanite from the El Muerto Pegmatite, Oaxaca, Mexico: A Potential New Standard for 232Th-208Pb Dating by LA-ICP-MS

    NASA Astrophysics Data System (ADS)

    Price, J.; Crowley, J. L.; Solari, L.; Prol-Ledesma, R.

    2012-12-01

    Allanite dating may be important to studies addressing tectonomagmatic evolution, provenance of monocyclic sediment, and mineral weathering. Obtaining accurate allanite ages by SIMS has been challenging and time-consuming due to the mineral's extreme chemical variability which often prevents finding adequately matrix-matched standards. Isotopic measurements by LA-ICP-MS minimize the need for standards of nearly identical composition to the unknown allanite being analyzed, and it is done relatively rapidly. Dating by LA-ICP-MS requires high quality standards for isotopic fractionation corrections. However, readily accessible and well characterized allanite standards are scarce. We investigated gemstone allanite from the El Muerto pegmatite, Oaxaca, Mexico, as a potential new geochronology standard for 232Th-208Pb allanite dating by LA-ICP-MS. Compositional homogeneity was thoroughly investigated by scanning and backscatter electron microscopy, cathodoluminescence, quantitative and qualitative energy dispersive x-ray spectroscopy, electron microprobe, and LA-ICP-MS. The possibility of metamictization was investigated by extensive X-ray diffraction analyses. The El Muerto allanite was U-Pb dated by ID-TIMS, with common Pb ratios determined from cogenetic K-feldspar by ID-TIMS and LA-MC-ICP-MS. Future work includes Th-Pb dating by ID-TIMS. The samples investigated are homogeneous with respect to major and trace elements. Major element compositional results are generally in agreement with published values, and no metamictization was identified despite the allanite being nearly 1 Ga. The only limitation of the El Muerto allanite is that it contains small, generally <100 μm, scarce inclusions of quartz, calciothorite, albite, calcite, and biotite. However, these grains are easily recognized and avoided during LA-ICP-MS analyses. Based on these results, the El Muerto allanite has the potential to serve as a standard for LA-ICP-MS dating.

  1. Distribution of terrestrial gamma radiation dose rate in the eastern coastal area of Odisha, India.

    PubMed

    Gusain, G S; Rautela, B S; Sahoo, S K; Ishikawa, T; Prasad, G; Omori, Y; Sorimachi, A; Tokonami, S; Ramola, R C

    2012-11-01

    Terrestrial gamma radiation is one of the important radiation exposures on the earth's surface that results from the three primordial radionuclides (226)Ra, (232)Th and (40)K. The elemental concentration of these elements in the earth's crust could result in the anomalous variation of the terrestrial gamma radiation in the environment. The geology of the local area plays an important role in distribution of these radioactive elements. Environmental terrestrial gamma radiation dose rates were measured around the eastern coastal area of Odisha with the objective of establishing baseline data on the background radiation level. The values of the terrestrial gamma radiation dose rate vary significantly at different locations in the study area. The values of the terrestrial gamma dose rate ranged from 77 to 1651 nGy h(-1), with an average of 230 nGy h(-1). During the measurement of the terrestrial gamma dose rate, sand and soil samples were also collected for the assessment of natural radionuclides. The activities of (226)Ra, (232)Th and (40)K from these samples were measured using a gamma-ray spectrometry with a NaI(Tl) detector. Activity concentrations of (226)Ra, (232)Th and (40)K ranged from 15.6 to 69 Bq kg(-1) with an average of 46.7 Bq kg(-1), from 28.9 to 973 Bq kg(-1) with an average of 250 Bq kg(-1) and from 139 to 952 Bq kg(-1) with an average of 429, respectively. The detailed significance of these studies has been discussed from the radiation protection point of view. PMID:22874894

  2. Natural radioactivity levels in soil samples from some areas of Himachal Pradesh, India using γ-ray spectrometry

    NASA Astrophysics Data System (ADS)

    Rani, Asha; Singh, Surinder

    226Ra, 232Th and 40K analysis has been carried out in soil samples collected from some areas of Himachal Pradesh, India using γ-ray spectrometry. The measured activity in soil ranges from 42.09 to 79.63 Bq kg -1, 52.83 to 105.81 Bq kg -1 and 95.33 to 160.30 Bq kg -1 for 226Ra, 232Th and 40K with the mean values of 57.34, 82.22 and 135.75 Bq kg -1, respectively. The measured activity concentration of 226Ra and 232Th in soil samples collected from these areas is higher and for 40K is lower than the world average. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report (370 Bq kg -1). The value of the external exposure dose has been determined from the content of these radionuclides in soil. It has been observed that on the average, the outdoor terrestrial gamma air absorbed dose rate is about 83.28 nGy h -1. The study yields an annual effective dose in the range of 0.07-0.13 mSv. The average value of annual effective dose lies in the global range of outdoor radiation exposure given in United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) [(2000). Effects and risks of ionizing radiations. UN, NY]. The activity concentration of 238U has also been determined using fission track technique and the values range from 3.26 to 7.71 mg kg -1 with a mean value of 4.38 mg kg -1.

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

    PubMed

    El-Gamal, Hany; Farid, M El-Azab; Abdel Mageed, A I; Hasabelnaby, M; Hassanien, Hassanien M

    2013-12-01

    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. PMID:23716081

  4. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    PubMed Central

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  5. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    PubMed Central

    Eštoková, Adriana; Palaščáková, Lenka

    2013-01-01

    The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices) of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in the cements ranged from 8.58–19.1 Bq·kg−1, 9.78–26.3 Bq·kg−1 and 156.5–489.4 Bq·kg−1 for 226Ra, 232Th and 40K, respectively. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Raeq = 67.87 Bq·kg−1, gamma index Iγ = 0.256, alpha index Iα = 0.067, the absorbed gamma dose rate D = 60.76 nGy·h−1, external hazard index Hex = 0.182 and internal hazard index Hin was 0.218. The radionuclide activity in composites ranged from 6.84–10.8 Bq·kg−1 for 226Ra, 13.1–20.5 Bq·kg−1 for 232Th and 250.4–494.4 Bq·kg−1 for 40K. The calculated radiological parameters of cements were lower than calculated radiological parameters of cement composites. PMID:24351739

  6. Assessment of environmental radioactivity for Batman, Turkey.

    PubMed

    Damla, Nevzat; Cevik, Ugur; Kobya, Ali Ihsan; Ataksor, Berna; Isik, Umit

    2010-01-01

    The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil, building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity concentrations of the natural radionuclides (226Ra, 232Th and 40K) and a fission product (137Cs) were 35+/-8, 25+/-10, 274+/-167 and 12+/-7 Bq kg(-1), respectively, in the soil samples. The concentrations of 226Ra, 232Th and 40K in the selected building materials ranged from 18 to 48 Bq kg(-1), 8 to 49 Bq kg(-1) and 68 to 477 Bq kg(-1), respectively. All the calculated radium equivalent (Raeq) activity values of the building material samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma-dose of 1.5 mSv year(-1). The activity concentrations of 226Ra, 232Th and 40K in tap waters collected from the study area were determined with mean specific activity concentrations of 42+/-15, 35+/-9 and 524+/-190 mBq L(-1), respectively. Indoor radon measurements were made at 95 dwellings in Batman using a CR-39 detector. The radon concentration levels were found to vary from 23 to 145 Bq m(-3). The arithmetic mean of the measured radon concentration levels was found to be 84 Bq m(-3) with a standard deviation value of 23 Bq m(-3). The measurement results obtained in this study did not significantly differ from those taken in other parts of the country. The data generated in this study can be used to determine whether the Batman province is in a normal or high background radiation area and provides a valuable database for future estimations of the impact of radioactive pollution. PMID:19083109

  7. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico.

    PubMed

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-10-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population's health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h(-1). At the same sites, 48 soil samples were taken to obtain the activity concentrations of (226)Ra, (232)Th and (40)K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h(-1). Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg(-1), for (226)Ra, (232)Th and (40)K, respectively. From the analysis, the spatial distribution of (232)Th, (226)Ra and (40)K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  8. Time features of delayed neutrons and partial emissive-fission cross sections for the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV

    SciTech Connect

    Roshchenko, V. A. Piksaikin, V. M. Korolev, G. G.; Egorov, A. S.

    2010-06-15

    The energy dependence of the relative abundances of delayed neutrons and the energy dependence of the half-lives of their precursors in the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV were measured for the first time. A systematics of the time features of delayed neutrons is developed. This systematics makes it possible to estimate the half-life of delayed-neutron precursors as a function of the nucleonic composition of fissile nuclei by using a single parameter set for all nuclides. The energy dependence of the partial cross sections for emissive fission in the reaction {sup 232}Th(n, f) was analyzed on the basis of data obtained for the relative abundances of delayed neutrons and the aforementioned half-lives and on the basis of the created systematics of the time features of delayed neutrons. It was shown experimentally for the first time that the decrease in the cross section after the reaction threshold in the fission of {sup 232}Th nuclei (it has a pronounced first-chance plateau) is not an exclusion among the already studied uranium, plutonium, and curium isotopes and complies with theoretical predictions obtained for the respective nuclei with allowance for shell, superfluid, and collective effects in the nuclear-level density and with allowance for preequilibrium neutron emission

  9. Natural Gamma Emitters after a Selective Chemical Separation of a TENORM residue: Preliminary Results

    SciTech Connect

    Alves de Freitas, Antonio; Abrao, Alcidio; Godoy dos Santos, Adir Janete; Pecequilo, Brigitte Roxana Soreanu

    2008-08-07

    An analytical procedure was established in order to obtain selective fractions containing radium isotopes ({sup 228}Ra), thorium ({sup 232}Th), and rare earths from RETOTER (REsiduo de TOrio e TErras Raras), a solid residue rich in rare earth elements, thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium nitrate at IPEN -CNEN/SP. The paper presents preliminary results of {sup 228}Ra, {sup 226}Ra, {sup 238}U, {sup 210}Pb, and {sup 40}K concentrations in the selective fractions and total residue determined by high-resolution gamma spectroscopy, considering radioactive equilibrium of the samples.

  10. Exposure of school children to polycyclic aromatic hydrocarbons, heavy metals and radionuclides in the urban soil of Kragujevac city, Central Serbia.

    PubMed

    Stajic, J M; Milenkovic, B; Pucarevic, M; Stojic, N; Vasiljevic, I; Nikezic, D

    2016-03-01

    The concentrations of radionuclides, polycyclic aromatic hydrocarbons (PAHs) and heavy metals were measured in soil samples collected from school backyards and playgrounds in Kragujevac, one of the largest cities of Central Serbia. The activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined using the HPGe semiconductor detector. The average values were 34.6, 44.7, 428.9 and 45.1 Bq kg(-1), respectively. The correlation between the activity concentrations of (226)Ra in the soil samples and the results of the previous measurement of (222)Rn concentrations in the indoor air was examined. The absorbed dose rates, the annual effective doses and excess lifetime cancer risk were also estimated. The activity concentrations of (226)Ra and (232)Th have shown normal distribution. The collected soil samples were analysed for PAHs by HPLC. All analysed soil samples contained PAHs, and their total amounts (for 15 measured compounds) were found to be between 0.038 and 3.136 mg kg(-1) of absolutely dry soil (a.d.s). In addition the concentrations of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in the fourteen soil samples collected from the playgrounds of kindergartens. PMID:26706933

  11. Environmental assessment of gamma-radiation levels in stream sediments around Sharm El-Sheikh, South Sinai, Egypt.

    PubMed

    Al-Sharkawy, A; Hiekal, M Th; Sherif, M I; Badran, H M

    2012-10-01

    A total surface area of ∼170 km(2) including 28 localities around Sharm El-Sheikh, South Sinai, were investigated by γ-ray spectroscopy. The concentrations of NORM were found to be five to seven-fold that in dune sands in different regions in Sinai. While relatively higher levels of (238)U, (234)Th, (226)Ra, and (232)Th are associated with the existing monzo-syenogranite, the concentration of (40)K is more uniformly distributed in the studied area. Locations with higher concentrations of (137)Cs are mainly located in the northern part. The (238)U, (234)Th and (226)Ra isotopes in the (238)U-series are in secular equilibrium. The absorbed dose rates and gamma-radiation hazard indices in all locations were higher than the world average value and unity, respectively. Properly regulated land use is recommended for a buffer zone in the northern part of the study area. PMID:22683899

  12. First measurements on how pressure affects the half-life of 22Na: Comparison to theory and analog to 40K

    NASA Astrophysics Data System (ADS)

    Lee, K. K.; Nelson, R. O.; Rundberg, R.; Steinle-Neumann, G.

    2007-12-01

    Radioactive decay plays a central role in planetary sciences as appropriate decay schemes are used to date geological and astronomical processes and radioactivity provides an important source of heat in planetary bodies, both in their early history during accretion and differentiation and also over geological times. The most important isotopes that currently heat the Earth are 40K, 232Th, 235U and 238U. As radioactive decay is a nuclear process it is considered to be insensitive to external factors such as pressure or chemical environment. This has been shown to be true for α, β+ and β- processes, however, electron capture decay is dependent on the electron charge density at the nucleus of a compound, which is sensitive to the external environment. Using high-resolution Ge gamma-ray detectors to make relative measurements with 137Cs and the positron decay of 22Na, we measure how pressure affects the half-life of 22Na due to electron-capture decay. Our systematics look favorable for observing this small effect. We will compare our preliminary measurements with complementary ab-initio all-electron computations using the linearized augmented plane wave method (LAPW). Using 22Na as an analog for 40K, our results suggest that the pressure effect for 40K, combined with the opposing effects of high temperatures, will have little, discernible effect on the heat production in the deep Earth as our predicted changes are smaller than the uncertainties in the total decay constant for 40K. This work was supported in part by the Carnegie/DOE Alliance Center (CDAC), through the Stewardship Science Academic Alliances Program of the U.S. Department of Energy. The LANSCE facility is operated, and portions of this work were performed, by Los Alamos National Security, LLC, funded by the U.S. Department of Energy under Contract No. DE-AC52- 06NA25396.

  13. The enrichment of natural radionuclides in oil shale-fired power plants in Estonia--the impact of new circulating fluidized bed technology.

    PubMed

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-03-01

    Burning oil shale to produce electricity has a dominant position in Estonia's energy sector. Around 90% of the overall electric energy production originates from the Narva Power Plants. The technology in use has been significantly renovated - two older types of pulverized fuel burning (PF) energy production units were replaced with new circulating fluidized bed (CFB) technology. Additional filter systems have been added to PF boilers to reduce emissions. Oil shale contains various amounts of natural radionuclides. These radionuclides concentrate and become enriched in different boiler ash fractions. More volatile isotopes will be partially emitted to the atmosphere via flue gases and fly ash. To our knowledge, there has been no previous study for CFB boiler systems on natural radionuclide enrichment and their atmospheric emissions. Ash samples were collected from Eesti Power Plant's CFB boiler. These samples were processed and analyzed with gamma spectrometry. Activity concentrations (Bq/kg) and enrichment factors were calculated for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides and for (40)K in different CFB boiler ash fractions. Results from the CFB boiler ash sample analysis showed an increase in the activity concentrations and enrichment factors (up to 4.5) from the furnace toward the electrostatic precipitator block. The volatile radionuclide ((210)Pb and (40)K) activity concentrations in CFB boilers were evenly distributed in finer ash fractions. Activity balance calculations showed discrepancies between input (via oil shale) and output (via ash fractions) activities for some radionuclides ((238)U, (226)Ra, (210)Pb). This refers to a situation where the missing part of the activity (around 20% for these radionuclides) is emitted to the atmosphere. Also different behavior patterns were detected for the two Ra isotopes, (226)Ra and (228)Ra. A part of (226)Ra input activity, unlike (228)Ra, was undetectable in the

  14. A semi-empirical approach to analyze the activities of cylindrical radioactive samples using gamma energies from 185 to 1764 keV.

    PubMed

    Huy, Ngo Quang; Binh, Do Quang

    2014-12-01

    This work suggests a method for determining the activities of cylindrical radioactive samples. The self-attenuation factor was applied for providing the self-absorption correction of gamma rays in the sample material. The experimental measurement of a (238)U reference sample and the calculation using the MCNP5 code allow obtaining the semi-empirical formulae of detecting efficiencies for the gamma energies ranged from 185 to 1764keV. These formulae were used to determine the activities of the (238)U, (226)Ra, (232)Th, (137)Cs and (40)K nuclides in the IAEA RGU-1, IAEA-434, IAEA RGTh-1, IAEA-152 and IAEA RGK-1 radioactive standards. The coincidence summing corrections for gamma rays in the (238)U and (232)Th series were applied. The activities obtained in this work were in good agreement with the reference values. PMID:25113537

  15. An assessment of natural radionuclides in water of Langat River estuary, Selangor

    NASA Astrophysics Data System (ADS)

    Hamzah, Zaini; Rosli, Tengku Nurliana Tuan Mohd; Saat, Ahmad; Wood, Ab. Khalik

    2014-02-01

    An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are 226Ra, 228Ra, 40K, 238U and 232Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of 226Ra, 228Ra and 40K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of 226Ra, 228Ra and 40K in samples are in the range of 0.17 - 0.67 Bq/L, 0.16 - 0.97 Bq/L and 1.22 - 5.57 Bq/L respectively. On the other hand, the concentrations of uranium-238 and thorium-232 were determined by using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The thorium concentrations are between 0.17 ppm to 0.28 ppm and uranium concentrations were 0.25 ppm to 0.31 ppm. The results show activity concentrations of radionuclides are slightly high near the river estuary. The Radium Equivalent, Absorbed Dose Rate, External Hazard Index, and Annual Effective Dose of 226Ra, 228Ra and 40K are also studied.

  16. An assessment of natural radionuclides in water of Langat River estuary, Selangor

    SciTech Connect

    Hamzah, Zaini Rosli, Tengku Nurliana Tuan Mohd Saat, Ahmad Wood, Ab. Khalik

    2014-02-12

    An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are {sup 226}Ra, {sup 228}Ra, {sup 40}K, {sup 238}U and {sup 232}Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of {sup 226}Ra, {sup 228}Ra and {sup 40}K in samples are in the range of 0.17 - 0.67 Bq/L, 0.16 - 0.97 Bq/L and 1.22 - 5.57 Bq/L respectively. On the other hand, the concentrations of uranium-238 and thorium-232 were determined by using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The thorium concentrations are between 0.17 ppm to 0.28 ppm and uranium concentrations were 0.25 ppm to 0.31 ppm. The results show activity concentrations of radionuclides are slightly high near the river estuary. The Radium Equivalent, Absorbed Dose Rate, External Hazard Index, and Annual Effective Dose of {sup 226}Ra, {sup 228}Ra and {sup 40}K are also studied.

  17. Study of natural radioactivity and estimation of radiation dose in the environment of Tumkur, Karnataka, India.

    PubMed

    Jayasheelan, A; Manjunatha, S; Yashodhara, I; Karunakara, N

    2014-01-01

    The activity concentration of (226)Ra, (232)Th and (40)K was measured for soil samples collected from 34 locations of Tumkur District, Karnataka, India, using HPGe detector. The activity concentration of (226)Ra, (232)Th and (40)K varied from 9.6 to 71.6, 12.3 to 333.3 and 194.3 to 1527.7 Bq kg(-1) with an average value of 33.15, 123.01 and 877.76 Bq kg(-1), respectively. The absorbed and annual effective outdoor doses were found to be highest at Ponnasamudra with 258.98 nGy h(-1) and 317.62 μSv and lowest at Sira with 36.42 nGy h(-1) and 44.67 μSv, respectively. The external hazard index ranged from 0.21 to 1.58 with an average of 0.75. It was significant in 11 locations as it exceeded unity. PMID:23907323

  18. Analysis of natural radionuclides in soil samples of Purola area of Garhwal Himalaya, India.

    PubMed

    Yadav, Manjulata; Rawat, Mukesh; Dangwal, Anoop; Prasad, Mukesh; Gusain, G S; Ramola, R C

    2015-11-01

    Naturally occurring radioactive materials are widely spread in the earth's environment, being distributed in soil, rocks, water, air, plants and even within the human body. All of these sources have contributed to an increase in the levels of environmental radioactivity and population radiation doses. This paper presents the activity level due to the presence of (226)Ra, (232)Th and (40)K in soil samples of Purola area in Garhwal Himalaya region. The measured activity of (226)Ra, (232)Th and (40)K in collected soil samples of Purola was found to vary from 13±10 to 55±10 Bq kg(-1) with an average of 31±2 Bq kg(-1), 13±10 to 101±13 Bq kg(-1) with an average 30±3 Bq kg(-1) and 150±81 to 1310±154 Bq kg(-1) with an average 583±30 Bq kg(-1), respectively. The radium equivalent activity in collected soil samples was found to vary from 47 to 221 Bq kg(-1) with an average of 115 Bq kg(-1). The total absorbed gamma dose rate in this area was found to vary from 22 to 93 nGy h(-1) with an average of 55 nGy h(-1). The distribution of these radionuclides in the soil of study area is discussed in details. PMID:25935014

  19. Transfer factor of the radionuclides in food crops from high-background radiation area of south west India.

    PubMed

    Shanthi, G; Thanka Kumaran, J Thampi; Gnana Raj, G Allen; Maniyan, C G

    2012-04-01

    It is necessary to obtain the transfer factor (TF) of long-lived radionuclides because soil type and vegetation can affect TF. We studied the food crops commonly consumed by the general public of Kanyakumari district of south India. The main focus was on rice, fruits, vegetables and tapioca because the consumption of these is high. The soil to rice TF for the radionuclides, (226)Ra, (232)Th, (238)U and (40) K are 8.8×10(-2), 14.2×10(-2), 5.8×10(-2) and 6.3×10(-2), respectively. The TF of tapioca for (226)Ra, (232)Th, (238)U and (40) K are 6.2×10(-2) , 11×10(-2), 1.9×10(-2) and 8.9×10(-2), respectively. For fruits and vegetables, the TFs are low. In the majority of the crops the non-edible parts accumulate more radionuclides than the edible parts. PMID:21680604

  20. Study of natural radionuclide and absorbed gamma dose in Ukhimath area of Garhwal Himalaya, India.

    PubMed

    Rautela, B S; Yadav, M; Bourai, A A; Joshi, V; Gusain, G S; Ramola, R C

    2012-11-01

    Natural radiation is the largest contributor to the collective radiation dose of the world population. It is widely distributed in different geological formations such as soil, rocks, air and groundwater. In the present investigation, (226)Ra, (232)Th and (40)K were measured in soil samples of the Ukhimath region of Garhwal Himalaya, India using NaI(Tl) gamma-ray spectrometry. The activity concentrations of naturally occurring radionuclides (226)Ra, (232)Th and (40)K were found to vary from 38.4 ± 6.1 to 141.7 ± 11.9 Bq kg(-1) with an average of 80.5 Bq kg(-1), 57.0 ± 7.5 to 155.9 ± 12.4 Bq kg(-1) with an average of 118.9 Bq kg(-1) and 9.0 ± 3.0 to 672.8 ± 25.9 Bq kg(-1) with an average of 341 Bq kg(-1), respectively. The total absorbed gamma dose rate varies from 70.4 to 169.1 nGy h(-1) with an average of 123.4 nGy h(-1). This study is important to generate a baseline data of radiation exposure in the area. Health hazard effects due to natural radiation exposure are discussed in details. PMID:22908360

  1. Distribution of gamma-ray emitting radionuclides in the environment of Burullus Lake: I. Soils and vegetations.

    PubMed

    El-Reefy, H I; Sharshar, T; Zaghloul, R; Badran, H M

    2006-01-01

    The concentrations and distribution of gamma-ray emitting isotopes in Burullus Lake were investigated with the aim of evaluating the environmental radioactivity. Particularly in wetlands, natural properties of the environment can cause the actual inventory to be different from the activity originally deposited. The mean concentrations of (226)Ra, (232)Th and (40)K were 14.3, 15.5 and 224 Bq/kg, respectively, in the coastal soils. On the other hand, soil samples from the islands had mean concentrations of 13.5, 17.4 and 341 Bq/kg for (226)Ra, (232)Th and (40)K, respectively. Samples from coast and islands show evidence of possible transfer and accumulation of the (137)Cs radionuclide. The mean (137)Cs activity concentrations in the soil samples were 1.2 and 15.1 Bq/kg in the coast and islands, respectively. The vertical migration of (137)Cs was studied based on its content in the consequently located three soil layers down to 30 cm depth. The radium equivalent, dose rate in air and annual dose equivalent from the terrestrial natural gamma-radiation were evaluated. The mean activity concentrations of the gamma-ray emitting radionuclides in vegetation were relatively low. PMID:16427723

  2. Distribution and environmental impacts of metals and natural radionuclides in marine sediments in-front of different wadies mouth along the Egyptian Red Sea Coast.

    PubMed

    el-Taher, A; Madkour, H A

    2011-02-01

    Forty-four marine sediment samples were collected in-front of wadis mouth along the Egyptian Red Sea coast: Wadi El-Hamra, Wadi El-Esh, Wadi Abu-Shaar, Wadi El-Gemal and Wadi Khashir (Hamata). Several investigations of natural activity and trace metals of surface sediments were carried out. Distributions of naturally occurring radioactive materials (NORM) of (226)Ra, (232)Th and (40)K in the marine sediments were determined using NaI (Tl) γ-ray spectrometry. The average activities (range) of natural radionuclides in all wadis in the studied areas are 27.38 (18-48) Bq kg(-1) for (226)Ra, 38.45 (34-110) Bq kg(-1) for (232)Th and 419.4 (214-641) Bq kg(-1) for (40)K. These results are in agreement with earlier reported data. A comparison of radionuclide activities in the sediment of the studied areas and in other coastal and aquatic environments is given. The radiation hazard parameters (absorbed dose rate, radium equivalent activity and external hazard index) are calculated and compared with the reported data. The results of measurements will serve as base line data and background reference level for Egyptian coastlines. PMID:21123076

  3. Radon exhalation rate and natural radionuclide content in building materials of high background areas of Ramsar, Iran.

    PubMed

    Bavarnegin, E; Fathabadi, N; Vahabi Moghaddam, M; Vasheghani Farahani, M; Moradi, M; Babakhni, A

    2013-03-01

    Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m(-2) h(-1). The (226)Ra, (232)Th and (40)K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of (226)Ra, (232)Th and (40)K content varied from below the minimum detection limit up to 86,400 Bq kg(-1), 187 Bq kg(-1) and 1350 Bq kg(-1), respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series. PMID:22280998

  4. Distribution of naturally occurring radioactivity and ¹³⁷Cs in the marine sediment of Farasan Island, southern Red Sea, Saudi Arabia.

    PubMed

    Al-Zahrany, A A; Farouk, M A; Al-Yousef, A A

    2012-11-01

    The present work is a part of a project dedicated to measure the marine radioactivity near the Saudi Arabian coasts of the Red Sea and Arabian Gulf for establishing a marine radioactivity database, which includes necessary information on the background levels of both naturally occurring and man-made radionuclides in the marine environment. Farasan Islands is a group of 84 islands (archipelago), under the administration of the Kingdom of Saudi Arabia, in the Red Sea with its main island of Farasan, which is 50 km off the coast of Jazan City. The levels of natural radioactivity of (238)U, (235)U, (226)Ra, (232)Th and (40)K and man-made radionuclides such as (137)Cs in the grab sediment and water samples around Farasan Island have been measured using gamma-ray spectroscopy. The average activity concentrations of (238)U, (235)U, (226)Ra, (232)Th, (40)K and (137)Cs in the sediment samples were found to be 35.46, 1.75, 3.31, 0.92, 34.34 and 0.14 Bq kg(-1), respectively. PMID:22923246

  5. Radioactivity in the Mediterranean flora of the Kaštela Bay, Croatia.

    PubMed

    Skoko, B; Marović, G; Babić, D

    2014-09-01

    This study refers to background activity concentrations of (238)U, (226)Ra, (232)Th, (208)Tl, (40)K, and (137)Cs in soil and plants of the Kaštela Bay, Croatia and related plant-soil concentration ratios (CR's). Fourteen different Mediterranean plant species growing in natural conditions have been included and were divided into three major plant groups (grasses and herbs, shrub, tree). Radionuclide activity concentrations were determined by means of high resolution gamma-ray spectrometry. Soil parameters (pH, electrical conductivity, and organic matter content) were also analysed. CR ranges were within one order of magnitude for (40)K (10(-2)-10(-1)), (238)U, and (226)Ra (10(-3)-10(-2)), and two orders of magnitude for (232)Th, (208)Tl, and (137)Cs (10(-4)-10(-2)). There was no statistical difference between the plant groups in radionuclide uptake. Overall statistical analyses indicated a moderate negative relationship between soil concentrations and CR values, and no relationship with soil parameters, except a negative one for (137)Cs. Comparison with literature showed more agreement with studies that were done in the Mediterranean than with ICRP and IAEA databases. Our data not only describe the natural radioactivity of the Bay, but also create a dataset that could be relevant for further radioecological assessments of the Kaštela Bay. PMID:24769388

  6. Natural radioactivity measurements of beach sands in Gran Canaria, Canary Islands (Spain).

    PubMed

    Arnedo, M A; Tejera, A; Rubiano, J G; Alonso, H; Gil, J M; Rodríguez, R; Martel, P

    2013-01-01

    Concentrations of natural radionuclides (226)Ra, (232)Th, (40)K and man-made (137)Cs in most important tourist Gran Canaria beaches have been determined using a high-purity Germanium detector to analyse their radiological hazard. Average values of the activity concentrations of (226)Ra, (232)Th and (40)K were 17.6±1.4, 21.3±1.8 and 480±22 Bq kg(-1), respectively. Observed activity concentration values of (137)Cs were practically negligible from a radiological protection point of view. The results of this paper were compared with others published in the bibliography for beaches and coastal sediments of different countries. The mean external air absorbed dose rate was 43.9±2.8 nGyh(-1), which resulted in an outdoor annual effective dose below the world average. Also, the radium equivalent and the external hazard index were calculated. Results from Gran Canaria beaches showed the low levels of radioactivity, indicating no significant radiological risk related to human activities in the area. PMID:23509399

  7. Assessment of natural radiation exposure levels and mass attenuation coefficients of lime and gypsum samples used in Turkey.

    PubMed

    Damla, Nevzat; Cevik, Uğur; Kobya, Ali Ihsan; Celik, Ahmet; Celik, Necati

    2010-11-01

    The activity concentrations of 226Ra, 232Th, and 40K in lime and gypsum samples used as building materials in Turkey were measured using gamma spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 38±16, 20±9, and 156±54 Bq kg(-1) for lime and found to be 17±6, 13±5, and 429±24 Bq kg(-1) for gypsum, respectively. The radiological hazards due to the natural radioactivity in the samples were inferred from calculations of radium equivalent activities (Raeq), indoor absorbed dose rate in the air, the annual effective dose, and gamma and alpha indices. These radiological parameters were evaluated and compared with the internationally recommended limits. The experimental mass attenuation coefficients (μ/ρ) of the samples were determined in the energy range 81-1,332 keV. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It is found that the calculated values and the experimental results are in good agreement. PMID:19921450

  8. Characterization of gas concrete materials used in buildings of Turkey.

    PubMed

    Damla, N; Cevik, U; Kobya, A I; Celik, A; Van Grieken, R; Kobya, Y

    2009-09-15

    The activity concentration of (226)Ra, (232)Th and (40)K in gas concrete samples collected from different suppliers and some provinces in Turkey were measured using gamma-ray spectrometry. Knowledge of radioactivity in gas concrete used in building materials enables one to assess any possible radiological risks to human health. The mean activity concentrations observed in the gas concrete samples were 82.0, 28.2 and 383.9 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The radium equivalent activity, external and internal hazard indices as well as terrestrial absorbed dose and annual effective dose rate was calculated. The results indicate that the radium equivalent activity values of gas concrete samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma-dose of 1.5 mSv y(-1). Moreover, mass attenuation coefficients were measured in some gas concrete samples. It was found that the mass attenuation coefficients decreased with increasing photon energies. Also, chemical compositions and structural analysis (XRD and SEM) of the gas concrete samples were investigated. PMID:19297097

  9. The measurement of gamma-emitting radionuclides in beach sand cores of coastal regions of Ramsar, Iran using HPGe detectors.

    PubMed

    Tari, Marziyeh; Moussavi Zarandi, Sayyed Ali; Mohammadi, Kheirollah; Zare, Mohammad Reza

    2013-09-15

    Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. (226)Ra, (235)U, (232)Th, (40)K and (137)Cs analysis has been carried out in sand samples collected at six depth levels, from eight locations of the northern coast of Iran, Ramsar, using high-resolution gamma-ray spectroscopy. The average Specific activities of natural radionuclides viz., (226)Ra, (235)U, (232)Th, (40)K and (137)Cs, in the 0-36 cm depth sand were found as: 19.2±0.04, 2.67±0.17, 17.9±0.06, 337.5±0.61 and 3.35±0.12 Bq kg(-1), respectively. The effects of organic matter content and pH value of sand samples on the natural radionuclide levels were also investigated. Finally, the measured radionuclide concentrations in the Ramsar beach were compared with the world average values, as reported by UNSCEAR (2000). None of the studied beaches were considered as a radiological risk. PMID:23850123

  10. An assessment of the external radiological impact in granites and pegmatite in central Eastern Desert in Egypt with elevated natural radioactivity.

    PubMed

    Uosif, M A M; Abdel-Salam, L M

    2011-11-01

    The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples (granite Gabal Ras Barud, Eastern Desert in Egypt) by using gamma spectrometry (NaI (Tl) 3″×3″). The activities of (226)Ra, (232)Th series and (40)K are between (3.8±0.5 and 172.8±1135.1±56.8 8.6), (2.3±0.3 and 103.8±5.2) and (53.1±2.7 and 1135.1±56.8) Bq kg(-1), respectively. With average total annual dose being only 67.2 μSv y(-1), this value is about 6.72 % of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public. Geochemical studies revealed that Gabal Ras Barud is formed from a highly fractionated biotite granite, with SiO(2) >75 % and generally enriched in alkali with K/Na >8 %. PMID:21131664

  11. Radiation dose to Malaysian infants from natural radionuclides via consumption of powdered milk

    SciTech Connect

    Uwatse, Onosohwo Bemigho; Olatunji, Michael Adekunle; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd.

    2015-04-24

    Milk is the basic food stuff for the infants because they generally consume more milk on a daily basis as its minerals and proteins are essential for their growth and development, therefore, it is very important to assess the natural radioactivity levels and the associated dose in the widely consumed powered infant’s milk. As a result, 14 brands of infant’s powdered milk were collected from different supermarkets around Selangor, Malaysia and analysed for {sup 226}Ra, {sup 232}Th and {sup 40}K activities. The obtained mean activity of {sup 226}Ra, {sup 232}Th and {sup 40}K are 3.05±1.84, 2.55±2.48 and 99.1±69.5 Bqkg{sup −1}, respectively. Among the analysed milk samples, the brand from Philippines (Lactogen) showed low level of radioactivity while Singaporean brand (S26 SMA Gold) showed the highest. The estimated mean annual effective doses due to the ingestion of natural radionuclides in the sampled milk are 635 and 111 µSv for infant ≤ 1y and infant 1-2y, respectively. The obtained dose value does not yet pose any significant radiological hazards to the population under investigation comparing with the 1.0 mSvy{sup −1} recommended by ICRP for all ages.

  12. Radioactive investigation of NORM samples from Southern Kuwait soil using high-resolution gamma-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Bajoga, A. D.; Alazemi, N.; Regan, P. H.; Bradley, D. A.

    2015-11-01

    Activity concentrations of soil and sand samples from southern part of Kuwait have been deduced for members of the 238U(226Ra) and 232Th(228Ac) decay chains, together with initial evaluations also provided of the concentrations for members of the 235U, 4n+1 chain. Additional activity concentration measurements have also been established for the single primordial radionuclide 40K and the anthropogenic radionuclides 137Cs from the same samples. The calculated activity concentration values and associated radiation hazard indices calculated were evaluated. The current results indicate activity concentrations ranging from 0.15±0.04 to 9.97±0.20 Bq/kg for Cs. For 226Ra, 232Th and 40K this ranges from 9.02±0.13 to 17.48±0.18, 7.90±0.10 to 14.29±0.22, and 259.6±4.7 137Cs to 347.3±6.0 Bq/kg, respectively. The mean values for dose rates, radium equivalent, hazard indices, and annual effective dose equivalent are 24.65±0.26 nG/h, 50.72±0.50 Bq/kg, 0.17, 0.14, and 30.0±0.3 μSv/yr, respectively. These are compared with analogous measurements from other locations both in the Middle Eastern Region and far-afield.

  13. Radioactivity measurement of primordial radionuclides in and dose evaluation from marble and glazed tiles used as covering building materials in Turkey.

    PubMed

    Turhan, Ş; Varinlioğlu, A

    2012-09-01

    Measurements of the natural radioactivity arising from primordial radionuclides ((226)Ra, (232)Th and (40)K) in marble and glazed tile samples used covering building materials in Turkey were carried out by gamma-ray spectrometer with a high purity germanium detector. The mean activity concentrations of the (226)Ra, (232)Th and (40)K in marble and glazed tile samples were found as 8.2, 5.5 and 58.1 Bq kg(-1) and 81.2, 65.4 and 450.1 Bq kg(-1), respectively. The radiation doses received by occupants of buildings in which the sample marble and glazed tiles might be used are estimated using measured activity concentrations of constituent primordial radionuclides and dose conversion factors evaluated by the European Commission from models of tile use. Results obtained are presented for each radionuclide, analysed and compared with relevant national and international legislation, guidance and report, and with the results obtained from other studies. Results show that the use of such decorative building materials in the construction of domestic homes or workplaces in Turkey is unlikely to lead to any significant radiation exposure to the occupants. PMID:22492819

  14. Evaluation of natural radioactivity content in high-volume surface water samples along the northern coast of Oman Sea using portable high-resolution gamma-ray spectrometry.

    PubMed

    Zare, Mohammad Reza; Kamali, Mahdi; Omidi, Zohre; Khorambagheri, Mahdi; Mortazavi, Mohammad Seddigh; Ebrahimi, Mahmood; Akbarzadeh, Gholamali

    2015-06-01

    Portable high-resolution gamma-ray spectrometry was carried out to determine the natural radioactivity levels in high volume surface water samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz strait to Goatr seaport, for the first time. The water samples from 36 coastal and near shore locations were collected for analysis. Analyses on the samples collected were carried out to determine (226)Ra, (232)Th and (40)K contents. The concentration of (226)Ra, (232)Th and (40)K in surface water samples ranged between 2.19 and 2.82 Bq/L, 1.66-2.17 Bq/L and 132.6-148.87 Bq/L, respectively. The activity profile of radionuclides shows low activity across the study area. The study also examined some radiation hazard indices. The external hazard index was found to be less than 1, indicating a low dose. The results of measurements will serve as background reference level for Oman Sea coastlines. PMID:25847859

  15. Assessment of ambient gamma dose rate around a prospective uranium mining area of South India - A comparative study of dose by direct methods and soil radioactivity measurements

    NASA Astrophysics Data System (ADS)

    Karunakara, N.; Yashodhara, I.; Sudeep Kumara, K.; Tripathi, R. M.; Menon, S. N.; Kadam, S.; Chougaonkar, M. P.

    Indoor and outdoor gamma dose rates were evaluated around a prospective uranium mining region - Gogi, South India through (i) direct measurements using a GM based gamma dose survey meter, (ii) integrated measurement days using CaSO4:Dy based thermo luminescent dosimeters (TLDs), and (iii) analyses of 273 soil samples for 226Ra, 232Th, and 40K activity concentration using HPGe gamma spectrometry. The geometric mean values of indoor and outdoor gamma dose rates were 104 nGy h-1 and 97 nGy h-1, respectively with an indoor to outdoor dose ratio of 1.09. The gamma dose rates and activity concentrations of 226Ra, 232Th, and 40K varied significantly within a small area due to the highly localized mineralization of the elements. Correlation study showed that the dose estimated from the soil radioactivity is better correlated with that measured directly using the portable survey meter, when compared to that obtained from TLDs. This study showed that in a region having localized mineralization in situ measurements using dose survey meter provide better representative values of gamma dose rates.

  16. Radiation dose to Malaysian infants from natural radionuclides via consumption of powdered milk

    NASA Astrophysics Data System (ADS)

    Uwatse, Onosohwo Bemigho; Olatunji, Michael Adekunle; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd.

    2015-04-01

    Milk is the basic food stuff for the infants because they generally consume more milk on a daily basis as its minerals and proteins are essential for their growth and development, therefore, it is very important to assess the natural radioactivity levels and the associated dose in the widely consumed powered infant's milk. As a result, 14 brands of infant's powdered milk were collected from different supermarkets around Selangor, Malaysia and analysed for 226Ra, 232Th and 40K activities. The obtained mean activity of 226Ra, 232Th and 40K are 3.05±1.84, 2.55±2.48 and 99.1±69.5 Bqkg-1, respectively. Among the analysed milk samples, the brand from Philippines (Lactogen) showed low level of radioactivity while Singaporean brand (S26 SMA Gold) showed the highest. The estimated mean annual effective doses due to the ingestion of natural radionuclides in the sampled milk are 635 and 111 µSv for infant ≤ 1y and infant 1-2y, respectively. The obtained dose value does not yet pose any significant radiological hazards to the population under investigation comparing with the 1.0 mSvy-1 recommended by ICRP for all ages.

  17. Radioactivity of a Rock Profile from Rio do Rasto Formation Measured by High Resolution Gamma Spectrometry

    NASA Astrophysics Data System (ADS)

    Bastos, Rodrigo O.; Appoloni, Carlos R.; Pinese, José P. P.

    2011-08-01

    Natural occurring radionuclides are present in different concentrations in sedimentary rocks. Generally, their distribution correlates reasonably with their geo-physicochemical behavior during sediment deposition and rock consolidation. This fact permits to study some geological characteristics of the rocks by analyzing the radionuclide distribution in the rocks, as it might reflect the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. In this work, rocks from an exposed profile of the Rio do Rasto Formation were collected and analyzed in laboratory by high resolution gamma spectrometry for 226Ra, 232Th and 40K determination. It was employed a standard gamma ray spectrometry electronic chain, with a 66% relative efficiency HPGe detector. The efficiency calibration, as well as its validation, was accomplished with eight International Atomic Energy Agency certified samples. The outcrop exposes layers of sandstone and siltstone and, secondarily, claystone, with varying colors (gray, red and green). The rocks were collected along this profile, each of them was dried in the open air during 48 hours, grounded, sieved through 4 mm mesh and sealed in cylindrical recipients. The 226Ra, 232Th and 40K activity concentrations are presented, their distribution and the possible relations among activities are analyzed. The general pattern of radionuclides distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.

  18. Radiochemical characterization of mineral waters in the Eastern Black Sea Region, Turkey.

    PubMed

    Kobya, Yasar; Damla, Nevzat; Cevik, Ugur; Kobya, Ali Ihsan

    2011-11-01

    This study has evaluated the levels of natural radionuclides and chemical components of mineral waters in the Eastern Black Sea Region (Turkey). The mean activity concentrations of (226)Ra, (232)Th, (137)Cs, (40)K, gross alpha and gross beta were found as 129, 33, 28, 714, 125 and 170 mBq L(-1), respectively. Due to consumption of mineral waters, the radiological impact of them on the inhabitants was calculated by taking the annual intake into account through ingestion of aforementioned radionuclides. The estimated effective doses from mineral water were found to be 13.20 μSv year(-1) ((226)Ra), 2.74 μSv year(-1) ((232)Th), 0.13 μSv year(-1) ((137)Cs) and 1.62 μSv year(-1) ((40)K). The overall contribution of these radionuclides to the committed effective dose from a year's consumption of mineral water in the region is therefore estimated to be only 17.69%, which is in concordance with the recommended WHO value (100 μSv year(-1)). The chemical analysis results showed that these waters contain Na, Al, P, Cl, K, Ca, V, Mn, Fe, Ni, Cu and Zn elements. These values were evaluated and compared with the internationally verified values. This study provides important information for consumers and authorities because of their internal radiochemical exposure risk from mineral water intake. PMID:21327484

  19. Radiological characterization around the Afsin-Elbistan coal-fired power plant in Turkey

    SciTech Connect

    Ugur Cevik; Nevzat Damla; Bahadir Koz; Selim Kaya

    2008-01-15

    A radiological characterization of soil samples around the Afsin-Elbistan coal-fired thermal power plant in the Mediterranean region of Turkey was carried out. Moreover, activity concentrations and chemical analyses of coal samples used in this power plant and fly ash and slag samples originating from coal combustion were measured. For this purpose, coal, fly ash, slag, and soil samples were collected from this region. The analysis shows that the samples include relevant natural radionuclides such as {sup 226}Ra, {sup 232}Th and {sup 40}K. The mean activity concentrations of {sup 226}Ra, {sup 232}Th, and {sup 40}K were 167, 44, and 404 Bq.kg{sup -1}, respectively. Obtained values shows that the average radium equivalent activity, air-absorbed dose rate, annual effective dose, and external hazard index for all samples are 258 Bq.kg{sup -1}, 121 nGy.h{sup -1}, 148 {mu}Sv.y{sup -1}, and 0.7, respectively. The environmental effect of natural radionuclides caused by coal-fired power plants was considered to be negligible because the Ra{sub eq} values of the measured samples are generally lower than the limit value of 370 Bq.kg{sup -1}, equivalent to a gamma dose of 1.5 mSv.y{sup -1}. A comparison of the concentrations obtained in this work with other parts of the world indicates that the radioactivity content of the samples is not significantly different. 20 refs., 1 fig., 5 tabs.

  20. Specific activity of natural and anthropogenic radionuclides and radiological hazard assessment in surface soil samples collected along the Andaman sea coast in southern region of Thailand

    NASA Astrophysics Data System (ADS)

    Kessaratikoon, P.; Boonkrongcheep, R.; Benjakul, S.; Udomsomporn, S.

    2015-05-01

    The specific activities of natural (40K, 226Ra and 232Th) and anthropogenic radionuclides (137Cs) in 314 surface soil samples collected from three provinces (Phuket, Phang-Nga and Krabi) along the Andaman sea coast in southern region of Thailand were studied and evaluated. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system. It was found that the mean values of specific activities of 40K, 226Ra, 232Th and 137Cs were 2859.63 ± 209.83, 157.10 ± 8.06, 137.16 ± 7.26 and 4.88 ± 2.34 Bq/kg, respectively. Furthermore, four radiological hazard indices which are absorbed dose rate in air (D), radium equivalent activity (Raeq), external hazard index (Hex) and annual effective dose rate (AEDout) in the area under consideration were also calculated and came out to be 277.11 ± 16.96 nGy/h, 575.16 ± 34.67 Bq/kg, 1.55 ± 0.09 and 0.34 ± 0.02 mSv/y, respectively. The experimental results were also compared and found to be comparable with national and global radioactivity measurements and evaluations. Moreover, the radioactive contour maps of the investigated area were also created and presented in this paper.

  1. Neutron activation analysis of some building materials

    NASA Astrophysics Data System (ADS)

    Salagean, M. N.; Pantelica, A. I.; Georgescu, I. I.; Muntean, M. I.

    1999-01-01

    Concentrations of As, Au, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mo, Na, Nd, Rb, Sb, Sc, Sr, Ta, Tb, Th, U. Yb, W and Zn in seven Romanian building materials were determined by the Instrumental Neutron Activation Analysis (INAA) method using the VVR-S Reactor of NIPNE- Bucharest. Raw matarials used in cement obtaining ≈ 75% of limestone and ≈ 25% of clay, cement samples from three different factories, furnace slag, phosphogypsum, and a type of brick have been analyzed. The brick was compacted from furnace slay, fly coal ash, phosphogypsum, lime and cement. The U, Th and K concentrations determined in the brick are in agreement with the natural radioactivity measurements of226Ra,232Th and40K. These specific activities were found about twice and 1.5 higher than the accepted levels in the case of226Ra and232Th, as well as40K, respectively. By consequence, the investigated brick is considered a radioactive waste. The rather high content of Co, Cr, K, Th, and Zh in the brick is especially due to the slag and fly ash, the main componets. The presence of U, Th and K in slag is mainly correlated with the limestone and dolomite as fluxes in matallurgy.

  2. Natural radioactivity hazards of building bricks fabricated from saline soil of two districts of Pakistan.

    PubMed

    Tufail, M; Nasim-Akhtar; Sabiha-Javied; Hamid, Tehsin

    2007-12-01

    Primordial radionuclides in building materials are one of the sources of radiation hazard in dwellings made of those materials. Activity concentrations of primordial radionuclides 40K, 226Ra and 232Th have been measured in house building bricks fabricated from saline soil. Forty samples of the bricks were collected from the brick fabrication sites and brick baking kilns in and around the saline soil areas of the districts of Lahore and Faisalabad in the Punjab province of Pakistan. The technique of gamma-ray spectroscopy using an HPGe detector with a PC-based multi-channel analyser was applied for determination of activity concentrations in the brick samples. The activity mass concentrations of 40K, 226Ra and 232Th measured in the brick samples were respectively 567.7 +/- 38.3 (493-631), 28.4 +/- 3.8 (23-35), and 56.0 +/- 4.6 (46-65) Bq kg(-1). The radiological hazards of the bricks were calculated using various models given in the literature. The radium equivalent activity was less than the accepted standard criterion value of 370 Bq kg(-1) and the values of other hazard indices were also below their limit values. The radiological hazard parameters of the bricks under investigation have been compared with those from other locations of Pakistan and also from some other countries in Asia. PMID:18268379

  3. Evaluation of some pollutant levels in environmental samples collected from the area of the new campus of Taif University.

    PubMed

    Sharshar, Taher; Hassan, H Ebrahim; Arida, Hassan A; Aydarous, Abdulkadir; Bazaid, Salih A; Ahmed, Mamdouh A

    2013-01-01

    The levels of radioactivity and heavy metals in soil, plant and groundwater samples collected from the area of the new campus of Taif University, Saudi Arabia, and its neighbouring areas have been determined. High-resolution gamma-ray spectroscopy was used for radioactivity measurements, and inductively coupled plasma atomic emission spectroscopy was used to determine the concentration of heavy metals. The means of (226)Ra, (228)Ra and (40)K concentrations in water samples collected from four wells were found to be 0.13 ± 0.03, 0.05 ± 0.03 and 1.3 ± 0.5 Bq l(-1), respectively. The means of (238)U, (226)Ra, (228)Ra ((232)Th for soil samples) and (40)K concentrations in wild plant and soil samples were found to be 3.7 ± 4.1, 8.8 ± 11.6, 3.8 ± 2.9 and 1025 ± 685, and 8.6 ± 3.4, 12.8 ± 3.4, 16.6 ± 7.1 and 618 ± 82 Bq kg(-1) dry weight (DW), respectively. The (137)Cs of artificial origin was also detected in soil samples with a mean concentration of 3.8 ± 2.2 Bq kg(-1) DW. Evaluating the results, it can be concluded that the concentrations of (238)U, (226)Ra, (232)Th and (40)K in soil samples fall within the world average. Furthermore, 19 trace and major elements in groundwater samples and 22 elements in soil and plant samples were determined. The sampling locations of soil can be classified into three groups (relatively high, medium and low polluted) according to their calculated metal pollution index using the contents of trace and major elements. A cluster analysis of the contents of radioactivity and trace element contents in soil samples shows the presence of two main distinct clusters of sampling locations. PMID:22568514

  4. Factors affecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake.

    PubMed

    El-Reefy, H I; Badran, H M; Sharshar, T; Hilal, M A; Elnimr, T

    2014-08-01

    In the present study, measurements of naturally occurring radioactive materials and (137)Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of (226)Ra and (232)Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of (137)Cs and (40)K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of (137)Cs and solubilization of (40)K in sediment. On the other hand, sediment with high organic matter content traps (137)Cs and (40)K associated particulates to bottom sediment. PMID:24657852

  5. Environmental characterization and radio-ecological impacts of non-nuclear industries on the Red Sea coast.

    PubMed

    El Mamoney, M H; Khater, Ashraf E M

    2004-01-01

    The Red Sea is a deep semi-enclosed and narrow basin connected to the Indian Ocean by a narrow sill in the south and to the Suez Canal in the north. Oil industries in the Gulf of Suez, phosphate ore mining activities in Safaga-Quseir region and intensified navigation activities are non-nuclear pollution sources that could have serious radiological impacts on the marine environment and the coastal ecosystems of the Red Sea. It is essential to establish the radiological base-line data, which does not exist yet, and to investigate the present radio-ecological impact of the non-nuclear industries to preserve and protect the coastal environment of the Red Sea. Some natural and man-made radionuclides have been measured in shore sediment samples collected from the Egyptian coast of the Red Sea. The specific activities of 226Ra and 210Pb (238U) series, 232Th series, 40K and 137Cs (Bq/kg dry weight) were measured using gamma ray spectrometers based on hyper-pure germanium detectors. The specific activities of 210Po (210Pb) and uranium isotopes (238U, 235U and 234U) (Bq/kg dry weight) were measured using alpha spectrometers based on surface barrier (PIPS) detectors after radiochemical separation. The absorbed radiation dose rates in air (nGy/h) due to natural radionuclides in shore sediment and radium equivalent activity index (Bq/kg) were calculated. The specific activity ratios of 228Ra/226Ra, 210Pb/226Ra, 226Ra/238U and 234U/238U were calculated for evaluation of the geo-chemical behaviour of these radionuclides. The average specific activity of 226Ra (238U) series, 232Th series, 40K and 210Pb were 24.7, 31.4, 427.5 and 25.6 Bq/kg, respectively. The concentration of 137Cs in the sediment samples was less than the lower limit of detection. The Red Sea coast is an arid region with very low rainfall and the sediment is mainly composed of sand. The specific activity of 238U, 235U and 234U were 25.3, 2.9 and 25.0 Bq/kg. The average specific activity ratios of 226Ra/228Ra, 210

  6. Use of Electrodeposition for Sample Preparation and Rejection Rate Prediction for Assay of Electroformed Ultra High Purity Copper for 232Th and 238U Prior to Inductively Coupled Plasma Mass Spectrometry (ICP/MS)

    SciTech Connect

    Hoppe, Eric W.; Aalseth, Craig E.; Brodzinski, Ronald L.; Day, Anthony R.; Farmer, Orville T.; Hossbach, Todd W.; McIntyre, Justin I.; Miley, Harry S.; Mintzer, Esther E.; Seifert, Allen; Smart, John E.; Warren, Glen A.

    2008-07-01

    The search for neutrinoless double beta decay in 76Ge has driven the need for ultra-low background Ge detectors shielded by electroformed copper of ultra-high radiopurity (<0.1µBq/kg). Although electrodeposition processes are almost sophisticated enough to produce copper of this purity, to date there are no methods sensitive enough to assay it. Inductively-coupled plasma mass spectrometry (ICP/MS) can detect thorium and uranium at femtogram levels, but in the past, this assay has been hindered by high copper concentrations in the sample. Electrodeposition of copper samples removes copper from the solution while selectively concentrating thorium and uranium contaminants to be assayed by ICP/MS. Spiking 232Th and 238U into the plating bath simulates low purity copper and allows for the calculation of the electrochemical rejection rate of thorium and uranium in the electroplating system. This rejection value will help to model plating bath chemistry.

  7. Fission-fragment angular distributions and excitation functions in fission following complete fusion and targetlike-fragment fission reactions of 19F+232Th at near- and sub-barrier energies

    NASA Astrophysics Data System (ADS)

    Majumdar, N.; Bhattacharya, P.; Biswas, D. C.; Choudhury, R. K.; Nadkarni, D. M.; Saxena, A.

    1995-06-01

    The fragment angular distributions and excitation functions of the fission following complete fusion (FFCF) have been measured after separating them from targetlike-fragment fission (TLFF) for the 19F+232Th system in the bombarding energy range of 84.5 to 106.5 MeV. The fraction of the targetlike-fragment fission was observed to increase with decreasing bombarding energy below the Coulomb barrier. The excitation function for fission following complete fusion reaction agrees well with coupled channel calculations. However, the values derived from the fragment anisotropy data of the FFCF events are found to be much larger than those calculated using the coupled channel transmission coefficient values. The discrepancy between the experimental and calculated values increases as the bombarding energy is decreased below the barrier.

  8. Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review.

    PubMed

    Papastefanou, Constantin

    2010-03-01

    Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of (40)K and of (238)U, (232)Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y(-1)), the major part of which (99%) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg(-1) for (238)U, from 44 to 255 Bq kg(-1) for (226)Ra, from 59 to 205 Bq kg(-1) for (210)Pb, from 9 to 41 Bq kg(-1) for (228)Ra ((232)Th) and from 59 to 227 Bq kg(-1) for (40)K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg(-1) for (238)U, from 142 to 605 Bq kg(-1) for (226)Ra, from 133 to 428 Bq kg(-1) for (210)Pb, from 27 to 68 Bq kg(-1) for (228)Ra ((232)Th) and from 204 to 382 Bq kg(-1) for (40)K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5man-Sv(GWa)(-1) for typical old and modern coal-fired power plants, respectively. PMID:20005612

  9. Radioactivity in honey of the central Italy.

    PubMed

    Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura; Benedetti, Claudio

    2016-07-01

    Natural radionuclides and (137)Cs in twenty seven honeys produced in a region of the Central Italy were determined by alpha ((235)U, (238)U, (210)Po, (232)Th and (228)Th) and gamma spectrometry ((137)Cs, (40)K, (226)Ra and (228)Ra). The study was carried out in order to estimate the background levels of natural ((40)K, (238)U and (232)Th and their progeny) and artificial radionuclides ((137)Cs) in various honey samples, as well as to compile a data base for radioactivity levels in that region. (40)K showed a mean activity of 28.1±23.0Bqkg(-1) with a range of 7.28-101Bqkg(-1). The mean of (210)Po activity resulted 0.40±0.46Bqkg(-1) with a range of 0.03-1.98Bqkg(-1). The mean of (238)U activity resulted 0.020±0.010Bqkg(-1). (226)Ra and (228)Ra resulted always <0.34 and <0.57Bqkg(-1) respectively, (235)U, (228)Th and (232)Th were always <0.007Bqkg(-1). (137)Cs resulted <0.10Bqkg(-1) in all samples. The committed effective doses due to (210)Po from ingestion of honey for infants, children and adults account for 0.002-5.13% of the natural radiation exposure in Italy. The honeys produced in Central Italy were of good quality in relation to the studied parameters, confirming the general image of a genuine and healthy food associated to this traditional products. PMID:26920304

  10. Assessment of Natural Radioactivity Levels and Potential Radiological Risks of Common Building Materials Used in Bangladeshi Dwellings.

    PubMed

    Asaduzzaman, Khandoker; Mannan, Farhana; Khandaker, Mayeen Uddin; Farook, Mohideen Salihu; Elkezza, Aeman; Amin, Yusoff Bin Mohd; Sharma, Sailesh; Abu Kassim, Hasan Bin

    2015-01-01

    The concentrations of primordial radionuclides (226Ra, 232Th and 40K) in commonly used building materials (brick, cement and sand), the raw materials of cement and the by-products of coal-fired power plants (fly ash) collected from various manufacturers and suppliers in Bangladesh were determined via gamma-ray spectrometry using an HPGe detector. The results showed that the mean concentrations of 226Ra, 232Th and 40K in all studied samples slightly exceeded the typical world average values of 50 Bq kg(-1), 50 Bq kg(-1) and 500 Bq kg(-1), respectively. The activity concentrations (especially 226Ra) of fly-ash-containing cement in this study were found to be higher than those of fly-ash-free cement. To evaluate the potential radiological risk to individuals associated with these building materials, various radiological hazard indicators were calculated. The radium equivalent activity values for all samples were found to be lower than the recommended limit for building materials of 370 Bq kg(-1), with the exception of the fly ash. For most samples, the values of the alpha index and the radiological hazard (external and internal) indices were found to be within the safe limit of 1. The mean indoor absorbed dose rate was observed to be higher than the population-weighted world average of 84 nGy h(-1), and the corresponding annual effective dose for most samples fell below the recommended upper dose limit of 1 mSv y(-1). For all investigated materials, the values of the gamma index were found to be greater than 0.5 but less than 1, indicating that the gamma dose contribution from the studied building materials exceeds the exemption dose criterion of 0.3 mSv y(-1) but complies with the upper dose principle of 1 mSv y(-1). PMID:26473957

  11. Natural radioactivity and radon exhalation rate in Brazilian igneous rocks.

    PubMed

    Moura, C L; Artur, A C; Bonotto, D M; Guedes, S; Martinelli, C D

    2011-07-01

    This paper reports the natural radioactivity of Brazilian igneous rocks that are used as dimension stones, following the trend of other studies on the evaluation of the risks to the human health caused by the rocks radioactivity as a consequence of their use as cover indoors. Gamma-ray spectrometry has been utilized to determine the (40)K, (226)Ra and (232)Th activity concentrations in 14 rock types collected at different quarries. The following activity concentration range was found: 12.18-251.90 Bq/kg for (226)Ra, 9.55-347.47 Bq/kg for (232)Th and 407.5-1615.0 Bq/kg for (40)K. Such data were used to estimate Ra(eq), H(ex) and I(γ), which were compared with the threshold limit values recommended in literature. They have been exceeded for Ra(eq) and H(ex) in five samples, where the highest indices corresponded to a rock that suffered a process of ductile-brittle deformation that caused it a microbrecciated shape. The exhalation rate of Rn and daughters has also been determined in slabs consisting of rock pieces ~10 cm-long, 5 cm-wide and 3 cm-thick. It ranged from 0.24 to 3.93 Bq/m(2)/h and exhibited significant correlation with eU (=(226)Ra), as expected. The results indicated that most of the studied rocks did not present risk to human health and may be used indoors, even with low ventilation. On the other hand, igneous rocks that yielded indices above the threshold limit values recommended in literature may be used outdoors without any restriction or indoors with ample ventilation. PMID:21459585

  12. Assessment of Natural Radioactivity Levels and Potential Radiological Risks of Common Building Materials Used in Bangladeshi Dwellings

    PubMed Central

    Asaduzzaman, Khandoker; Mannan, Farhana; Khandaker, Mayeen Uddin; Farook, Mohideen Salihu; Elkezza, Aeman; Amin, Yusoff Bin Mohd; Sharma, Sailesh; Abu Kassim, Hasan Bin

    2015-01-01

    The concentrations of primordial radionuclides (226Ra, 232Th and 40K) in commonly used building materials (brick, cement and sand), the raw materials of cement and the by-products of coal-fired power plants (fly ash) collected from various manufacturers and suppliers in Bangladesh were determined via gamma-ray spectrometry using an HPGe detector. The results showed that the mean concentrations of 226Ra, 232Th and 40K in all studied samples slightly exceeded the typical world average values of 50 Bq kg−1, 50 Bq kg−1 and 500 Bq kg−1, respectively. The activity concentrations (especially 226Ra) of fly-ash-containing cement in this study were found to be higher than those of fly-ash-free cement. To evaluate the potential radiological risk to individuals associated with these building materials, various radiological hazard indicators were calculated. The radium equivalent activity values for all samples were found to be lower than the recommended limit for building materials of 370 Bq kg-1, with the exception of the fly ash. For most samples, the values of the alpha index and the radiological hazard (external and internal) indices were found to be within the safe limit of 1. The mean indoor absorbed dose rate was observed to be higher than the population-weighted world average of 84 nGy h–1, and the corresponding annual effective dose for most samples fell below the recommended upper dose limit of 1 mSv y–1. For all investigated materials, the values of the gamma index were found to be greater than 0.5 but less than 1, indicating that the gamma dose contribution from the studied building materials exceeds the exemption dose criterion of 0.3 mSv y-1 but complies with the upper dose principle of 1 mSv y−1. PMID:26473957

  13. High precision determination of the terrestrial 40K abundance

    NASA Astrophysics Data System (ADS)

    Naumenko, Maria O.; Mezger, Klaus; Nägler, Thomas F.; Villa, Igor M.

    2013-12-01

    Recent improvements in the precision of mass spectrometric measurements have reduced the uncertainty of K-Ar and 39Ar-40Ar ages measured on geological materials. Now the major sources of uncertainty are the uncertainties on the 40K decay constant and the absolute abundance of 40K. In order to improve on this situation we determined the abundance of the 40K isotope in terrestrial standards. A ThermoFischer Triton+ thermal ionization mass spectrometer was used for K isotope ratio measurements of the NIST K standard reference materials SRM 918b and SRM 985. Ion beams were measured in Faraday cups with amplifiers equipped with 1010, 1011 and 1012 Ω resistors. Three measurement protocols were used: (A) dynamic measurement with in-run fractionation correction by normalization to the IUPAC recommended isotope ratio 41K/39K = 0.072 1677; (B) total evaporation; (C) a modified total evaporation with interblock baseline measurements. Different measurement protocols were combined with different loading procedures. The best results were obtained by loading samples on single oxidized tantalum filaments with 0.1 M H3PO4. The total ion yields (ionization + transmission) were tested for the evaporation procedures (B) and (C) and ranged up to 48%. The resulting best estimate for the 40K/39K ratio is 0.000 125 116 ± 57 (2σ), corresponding to an isotopic abundance 40K/K = (1.1668 ± 8) × 10-4.

  14. Disequilibrium in naturally occurring radioactive series in some phosphate ores.

    PubMed

    Hamidalddin, Safia H Q; Fakeha, Afaf A; Yeslam, Mai S; Ibraheim, Nagdya M

    2012-01-01

    Eight phosphate ore samples from Egypt and Saudi Arabia were studied by atomic absorption spectrometry for the Bi, Pb, Th and Al concentrations in ppm or ppb or per cent. Also X-ray diffraction spectrometry was applied for determining the mineral and chemical composition of the phosphate ore samples. A gamma spectrometry system, based on HPGe crystal, was applied for determining the concentrations of the radioactive elements in (238)U, (226)Ra and (232)Th series as well as (40)K, in Bq/kg dry weight. Concentrations in ppm were found to be from <10.0 to 20.48, from <7.50 to 27.30 and from <1.0 to 50.0 for Bi, Pb and Th, respectively. Al ranged from <0.05 to 3.13%. Major, minor and trace chemical and mineral compositions were assigned for each sample by XRD spectrometry. Concentrations of the different elements in both radioactive series, (238)U, (226)Ra and (232)Th were compared. Disequilibrium was found in both series. PMID:21982734

  15. Radiological and chemical assessment of phosphate rocks in some countries.

    PubMed

    Cevik, U; Baltas, H; Tabak, A; Damla, N

    2010-10-15

    In this study, the radiological, structural and chemical characterizations of Mardin-Mazidaği phosphate rock, which is an important phosphate fertilizer source in Turkey were investigated and compared to those of several different phosphate rocks of Tunisia, Egypt, Morocco, Algeria and Syria using gamma spectrometry, X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurement techniques. Elemental analysis results of phosphate samples showed that they were mainly composed of CaO, P(2)O(5), SiO(2), Al(2)O(3), SO(3) and Fe(2)O(3). Elemental concentrations of U and Th were calculated using (226)Ra and (232)Th activity concentrations, respectively. As a result of XRD analysis, the main peaks of the samples were found to be Fluorapatite (Ca(5)(PO(4))(3)F). The radioactivity concentration levels for (226)Ra, (232)Th and (40)K in all phosphate samples ranged from 250 to 1029 Bq kg(-1) with a mean of 535 Bq kg(-1), from 5 to 50 Bq kg(-1) with a mean of 20 Bq kg(-1) and from 117 to 186 Bq kg(-1) with a mean of 148 Bq kg(-1), respectively. The computed values of annual effective doses ranged from 0.17 to 0.59 mSv, with a mean value of 0.33 mSv, which is lower than the recommended limit of 1 mSv y(-1) by the International Commission on Radiological Protection. PMID:20630655

  16. Radioactivity In Marine Organisms From Northeast Atlantic Ocean

    SciTech Connect

    Carvalho, Fernando P.; Oliveira, Joao M.

    2008-08-07

    Naturally-occurring radionuclides such as {sup 238}U, {sup 234}U, {sup 230}Th, {sup 226}Ra, {sup 210}Po, {sup 210}Pb and {sup 232}Th, and artificial radionuclides such as {sup 137}Cs, {sup 239+240}Pu and {sup 241}Am, were measured in a large number of marine species. In common fish species, typical concentrations of {sup 210}Po ranged from 10{sup 2} to 10{sup 4} mBq kg{sup -1} (wet weight), {sup 226}Ra concentrations ranged from 1x10{sup 2} to 5xl0{sup 2} mBq kg{sup -1}, {sup 238}U was at about 10 mBq kg{sup -1} and {sup 232}Th at about 0.5 mBq kg{sup -1}. Radiation doses to marine organisms originated by naturally-occurring and artificial radionuclides accumulated in tissues and by external radiation sources were computed and compared. Internal sources generally give higher contribution to the absorbed radiation dose than external sources. Amongst radionuclides accumulated in fish muscle and acting as internal radiation sources, natural {sup 210}Po and {sup 40}K give the largest contribution to the absorbed radiation dose, while artificial radionuclides such as {sup 137}Cs and {sup 239+240}Pu contribute with less than 0.5% to the absorbed radiation dose from all internal sources.

  17. Distribution, enrichment and principal component analysis for possible sources of naturally occurring and anthropogenic radionuclides in the agricultural soil of Punjab state, India.

    PubMed

    Kumar, Ajay; Joshi, Vikram M; Mishra, Manish K; Karpe, Rupali; Rout, Sabyasachi; Narayanan, Usha; Tripathi, Raj M; Singh, Jaspal; Kumar, Sanjeev; Hegde, Ashok G; Kushwaha, Hari S

    2012-06-01

    Enrichment factor (EF) of elements including geo-accumulation indices for soil quality and principal component analysis (PCA) were used to identify the contributions of the origin of sources in the studied area. Results of (40)K, (137)Cs, (238)U and (232)Th including their decay series isotopes in the agricultural soil of Mansa and Bathinda districts in the state of Punjab were presented and discussed. The measured mean radioactivity concentrations for (238)U, (232)Th and (40)K in the agricultural soil of the studied area differed from nationwide average crustal abundances by 51, 17 and 43 %, respectively. The sequence of the EFs of radionuclides in soil from the greatest to the least was found to be (238)U > (40)K > (226)Ra > (137)Cs > (232)Th > (228)Ra. Even though the enrichment of naturally occurring radionuclides was found to be higher, they remained to be in I(geo) class of '0', indicating that the soil is uncontaminated with respect to these radionuclides. Among non-metals, N showed the highest EF and belonged to I(geo) class of '2', indicating that soil is moderately contaminated due to intrusion of fertiliser. The resulting data set of elemental contents in soil was also interpreted by PCA, which facilitates identification of the different groups of correlated elements. The levels of the (40)K, (238)U and (232)Th radionuclides showed a significant positive correlation with each other, suggesting a similar origin of their geochemical sources and identical behaviour during transport in the soil system. PMID:21893521

  18. Determination of the risk associated with the natural and anthropogenic radionuclides from the soil of Skardu in Central Karakoram.

    PubMed

    Ali, Manzoor; Wasim, Mohammad; Iqbal, Sajid; Arif, Mohammad; Saif, Farhan

    2013-09-01

    The radioactivity levels were determined in 39 soil samples from six towns of Skardu using gamma-ray spectrometry. The samples were collected at an average altitude of 2293 m above sea level in Central Karakoram. The activity concentration data were analysed by principal component analysis for outlier detection and data structure elucidation and for frequency distributions. The median activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were found to be 49.8 ± 12.6, 80.9 ± 18.7, 977 ± 91 and 4.37 ± 4.08 Bq kg(-1), respectively. An uncertainty analysis showed that the main contribution to uncertainty budget was from the counting statistics and uncertainty in the reference activity of standard. The activity concentration data showed a positive significant correlation between (226)Ra and (232)Th. Three hazard indices named the radium equivalent activity, external hazard index and internal hazard index were calculated. In the total activity concentration, (40)K accounted for the most (87.5 %), whilst in the radium equivalent activity, (232)Th contributed the most (48.5 %). In the Skardu samples, the air-absorbed dose rate was found to be 112 ± 17 nGy h(-1), annual effective dose rate from terrestrial to be 243 ± 38 μSv y(-1), effective dose rate due to the deposition of (137)Cs on soil to be 1.1 ± 2.4 μSv y(-1) and dose rate from the cosmic radiations to be 1371 ± 107 μSv y(-1). The ratio of mass fractions of Th/U was 4.8 ± 0.6.The results were compared with the similar measurements made in other parts of the world. A comparison with the other cities of Pakistan revealed that the soil in Skardu presented the highest external exposure rate. PMID:23525911

  19. Terrestrial gamma dose rate, radioactivity and radiological hazards in the rocks of an elevated radiation background in Juban District, Ad Dali' Governorate, Yemen.

    PubMed

    Abdurabu, Wedad Ali; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Heryansyah, Arien; Alnhary, Anees; Fadhl, Shadi

    2016-03-01

    This study aims to evaluate natural radiation and radioactivity in the rock and to assess the corresponding health risk in a region of elevated background radiation in Juban District, Ad Dali' Governorate, Yemen. The mean external gamma dose rate was 374 nGy h(-1) which is approximately six times the world average. The measured results were used to compute annual effective dose equivalent, collective effective dose and excess lifetime cancer risk, which are 2.298 mSv, 61.95 man Sv y(-1) and 8.043  ×  10(-3), respectively. Rocks samples from different geological formations were analyzed for quantitative determination of (226)Ra, (232)Th and (40)K. The specific activity of the rocks samples ranges from 7  ±  1 Bq Kg(-1) to 12 513  ±  329 Bq Kg(-1) for (232)Th, from 6  ±  1 Bq kg(-1) to 3089  ±  74 Bq kg(-1) for (226)Ra and 702  ±  69 Bq kg(-1) to 2954  ±  285 Bq kg(-1) for (40)K. (232)Th is the main contributor to gamma dose rate from the rock samples. Indicators of radiological health impact, radium equivalent activity and external hazard index are 3738 Bq kg(-1) and 10.10, respectively. The mean external hazard index was ten times unity in the studied locations in Juban District, which is higher than the recommended value. PMID:26909670

  20. Distribution of radionuclides in surface soils, Singhbhum Shear Zone, India and associated dose.

    PubMed

    Patra, A C; Sahoo, S K; Tripathi, R M; Puranik, V D

    2013-09-01

    Gamma emitters were estimated in surface soils from a mineralized zone in Eastern India using high purity Germanium detector-based high resolution gamma spectrometry system. Activities of (238)U, (226)Ra, (232)Th, (235)U, (227)Th, (234 m)Pa, (210)Pb, (40)K, and (137)Cs were 79 ± 50, 81 ± 53, 65 ± 23, 4 ± 2, 5 ± 4, 92 ± 50, 97 ± 45, 517 ± 201, and 4 ± 2 Bq/kg, respectively. Most radionuclides were observed to follow log-normal distribution. The correlation between physicochemical properties of the samples, like pH, organic matter content, particle size, and moisture content were also studied. Activity ratios of (226)Ra/(238)U, (210)Pb/(226)Ra, and (227)Th/(235)U indicated deviation from secular equilibrium in some samples. The associated annual effective dose ranged from 0.07 to 0.24 mSv and the mean was calculated to be 0.12 ± 0.04 mSv for this region, indicating it to be one of normal natural background radiation. PMID:23456273

  1. Assessment of public exposure to naturally occurring radioactive materials from mining and mineral processing activities of Tarkwa Goldmine in Ghana.

    PubMed

    Faanu, Augustine; Ephraim, James H; Darko, Emmanuel O

    2011-09-01

    Studies have been carried out in a Goldmine in Ghana to determine the exposure of the public to naturally occurring radioactive materials from processing of gold ore. Direct gamma spectrometry and neutron activation analysis techniques were used to analyse soil, rock, water and dust samples from the mining environment. The mean activity concentrations measured for (238)U, (232)Th and (40)K in the soil/rock samples were 15.2, 26.9 and 157.1 Bq kg( - 1), respectively. For the water samples, the mean activity concentrations were 0.54 and 0.41 Bq l( - 1)) and 7.76 Bq l( - 1) for (226)Ra, (232)Th and (40)K, respectively. The mean activity concentrations measured in the dust samples were 4.90 and 2.75 μBq m( - 3) for (238)U and (232)Th, respectively. The total annual effective dose to the public was estimated to be 0.69 mSv. The results in this study compared well with typical world average values. The results indicate an insignificant exposure of the public from the activities of the Goldmine. PMID:21072583

  2. Absolute photofission cross section of sup 197 Au, @Pb, sup 209 Bi, sup 232 Th, sup 238 U, and sup 235 U nuclei by 69-MeV monochromatic and polarized photons

    SciTech Connect

    Martins, J.B.; Moreira, E.L.; Tavares, O.A.P.; Vieira, J.L. Centro Brasileiro de Pesquisas Fisicas-CBPF, Rua Dr. Xavier Sigaud 150, 22290 Rio de Janeiro-RJ, ); Casano, L.; D'Angelo, A.; Schaerf, C. Istituto Nazionale di Fisica Nucleare-INFN, Sezione di Roma 2, Roma, ); Terranova, M.L. Istituto Nazionale di Fisica Nucleare-INFN, Sezione di Roma 2, Roma, Italy); Babusci, D. ); Girolami, B. Istituto Nazionale di Fisica Nuclea

    1991-07-01

    Absolute cross-section measurements for the photofission reactions of {sup 197}Au, {sup nat}Pb, {sup 209}Bi, {sup 232}Th, {sup 238}U, and {sup 235}U nuclei have been performed at an incident photon energy of 69 MeV using monochromatic and polarized photon beams and dielectric fission-track detectors. Nuclear fissility values have been obtained and results are in agreement with those from other laboratories, although in some cases discrepancies are observed between one other. For nuclei in the region of the actinides the fissility result is {approx gt}0.4, while for Au, Pb, and Bi nuclei it only is {similar to}10{sup {minus}3}--10{sup {minus}2}. Results have been interpreted in terms of the primary Levinger's quasideuteron nuclear photoabsorption followed by a mechanism of evaporation-fission competition for the excited nuclei. Shell effects have been taken into account, and they are clearly manifested when fissility is evaluated. The influence of photon polarization on photofission of {sup 238}U also has been investigated, and results have shown isotropy in the fragment azimuthal distribution.

  3. X-34 40K Fastrac II Engine Test

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This is a photo of an X-34 40K Fastrac II duration test performed at the Marshall Space Flight Center test stand 116 (TS116) in June 1997. Engine ignition is started with Tea-Gas which makes the start burn green. The X-34 program was cancelled in 2001.

  4. Assessment of radiological risk for marine biota and human consumers of seafood in the coast of Qingdao, China.

    PubMed

    Yang, Baolu; Ha, Yiming; Jin, Jing

    2015-09-01

    This paper reports the levels of (226)Ra, (232)Th, (40)K and (137)Cs in the edible parts of 11 different marine species collected from the Qingdao coast of China. The activities of (226)Ra, (232)Th and (40)K ranged from 0.08±0.03 to 1.65±0.60 Bq kg(-1) w.w., 0.09±0.02 to 1.44±0.10 Bq kg(-1) w.w., 26.89±1.25 to 219.25±5.61 Bq kg(-1) w.w., respectively. Artificial (137)Cs was undetectable or close to the detection limit in the biota sampled. To link radioactivity to possible impact on health, we calculated radiation doses to both the marine biota and human beings. We showed that doses in all cases were dominated by naturally occurring (40)K and that (137)Cs doses were negligible compared with (40)K-derived doses. The total doses to marine biota ranged between 16.55 and 62.41 nGy h(-1) among different biota species, which were below the benchmark level of aquatic organism. The committed effective dose to humans through seafood consumption varied from 10.55 to 36.17 μSv y(-1), and the associated lifetime cancer risks ranged from 5.93E-05 to 9.49E-05 for different age and gender groups. Both the dose and cancer risk to humans were at the acceptable range. Despite the significant amount of radionuclides released as a result of the Fukushima accident, their impact on the seafood in Qingdao coast appears to be negligible based on our measurements of concentrations of radionuclide activity and internal dose estimates. PMID:25985213

  5. A radiometric and petrographic approach to risk assessment at Alte Madonie Mounts region (Sicily, Italy).

    PubMed

    Lanzo, G; Rizzo, S; Tomarchio, E

    2014-03-01

    The main goal of this work was to assess the radiological hazard at Alte Madonie Mounts region (north-central Sicily, Italy) in response to rumours of an increase in the incidence of cancer in this area. A correlation between the natural radionuclide contents and the petrographic features of the soil and rock samples was also evaluated. A total of 41 samples of selected soils and rocks were collected, powdered, dried and sealed in 'Marinelli' beakers for 20 d prior to measurement to ensure that a radioactive equilibrium between (226)Ra and (214)Bi had been reached. A gamma-ray spectrometer was used to quantify the radioactivity concentrations. To determine (238)U and (232)Th activities, the 609.3-keV line from (214)Bi in secular equilibrium with (226)Ra and the 911-keV line from (228)Ac, with which (232)Th can be assumed to be in equilibrium, were used, respectively. The gamma transition of 1461 keV was used to determine (40)K activity. The average values of the concentrations of (214)Bi, (228)Ac and (40)K were 30, 17 and 227 Bq kg(-1), respectively, whereas the greatest values were 134, 59 and 748 Bq kg(-1), respectively. A linear relationship was found between the activity values of (214)Bi, (228)Ac and (40)K. An exception was found for a group of samples in which the (214)Bi activities were much higher than expected. The chemical compositions and mineralogical features of the samples permitted the justification of these anomalies. The results of the primordial radionuclide contents are reassuring from a radiation protection point of view because the activities of the uranium and thorium series products and of the (40)K do not present a significant radiological hazard. PMID:24106332

  6. High Precision 40K/39K Ratio Determination

    NASA Astrophysics Data System (ADS)

    Naumenko, M. O.; Mezger, K.; Nagler, T. F.; Villa, I. M.

    2012-12-01

    Potassium is one of the eight most abundant chemical elements in the Earth's crust and a major element in many rock-forming minerals. The isotope 40K is radioactive and undergoes β- decay to 40Ca (ca. 89.3%) and electron capture to 40Ar (ca. 10.7%). Both decays can potentially be used as dating systems. The most commonly used branch is the decay of 40K to 40Ar because it can yield highly precise ages. Both decay schemes rely on the knowledge of the 40K branching ratio and the natural 40K abundance. A 40K abundance of 0.011672±41 % was measured on terrestrial material [1]. The relative uncertainty of 0.35 % has not been improved since. Recent improvements in the precision of mass spectrometric measurements have led to the situation that the uncertainties on the K decay constant and the abundance of 40K are a major source of uncertainty on the measured ages. A more precise definition of the 40K decay constant was attempted by different research groups within the last decade [2-9] but the goal of obtaining 0.1 % relative uncertainty on K-Ar ages for geological materials, as requested by the EARTHtime initiative, has not been achieved yet. In order to improve on this situation we studied the abundances of the K isotopes in terrestrial standards. A ThermoFischer Triton+ thermal ionisation mass spectrometer was used for K isotope ratio measurements of the NIST SRM 918b K standard loaded on Ta filaments with 0.1M phosphoric acid. Three techniques were applied: (A) dynamic measurement with in-run normalisation to the IUPAC value 41K/39K=0.072168; (B) a simple total evaporation procedure; (C) the "NBL-modified" total evaporation [10]. The 40K ion beam was measured in a Faraday cup with a 1E12 Ω resistor; 39K and 41K were collected in Faraday cups with 1E11 Ω resistors. Amplifier gains were intercalibrated by supplying fixed voltages off-line. Different measurement techniques were combined with different loading procedures. We also tested ionisation yields for the

  7. Diffusion in the Muscovite 40K Decay System (Invited)

    NASA Astrophysics Data System (ADS)

    Harrison, T. M.

    2010-12-01

    The considerable potential of muscovite for thermochronological applications is beginning to be fully exploited following the belated publication of Ar kinetic data. Muscovite’s high potassium content, low solubility for excess 40Ar*, and ubiquitous presence in regionally metamorphosed terranes make it an important phase for 40Ar/39Ar thermochronometry, particularly in light of recognition that both age spectra and vacuum-step-heating-derived 39Ar Arrhenius plots reflect Ar release via the same volume diffusion mechanism. Thus instead of assuming a nominal closure temperature to estimate a single T-t datum, continuous and accurate thermal histories can be inferred in a similar fashion to that well-documented for K-feldspar using the multi-diffusion domain (MDD) model. The Arrhenius parameters for Ar diffusion in muscovite (E=64 kcal/mol, Do=4 cm2/s) correspond to an effective intragrain closure temperature range of ~500 to 300oC for ca. 100 μm grains cooling at ~10oC/Ma at 5 kbar. However, even greater exploitation of the 40K decay system remains possible as only one of every ten 40K atoms decay to 40Ar. The other 90% decay to 40Ca giving the 40K-40Ca branch, in principle, greater sensitivity for dating high K/Ca minerals such as muscovite. The advent of the ‘double-plus’ SIMS 40K++-40Ca++ dating method, which permits analysis of Ca isotopes at an MRP of ~4k rather than the ~25k required for full separation of 40K+ from 40Ca+, opens up the prospect of directly revealing 40K-40Ca closure profiles in muscovite (as opposed to their indirect inference from inversion of 40Ar/39Ar data through the MDD model) at a gain of enhanced precision and accuracy in thermal history reconstruction. We have used SIMS to observe K-Ca age variations in natural muscovites pressed into In. Translating this data into thermal history information, however, requires knowledge of the Arrhenius parameters for Ca tracer diffusion in muscovite. We are undertaking hydrothermal piston

  8. Commercial Modular Aero-Propulsion System Simulation 40k

    NASA Technical Reports Server (NTRS)

    Guo, Ten-Huei; Lavelle, Thomas; Litt, Jonathan; Csank, Jeffrey; May, Ryan

    2011-01-01

    The Commercial Modular Aero-Propulsion System Simulation 40k (CMAPSS40k) software package is a nonlinear dynamic simulation of a 40,000-pound (approximately equals 178-kN) thrust class commercial turbofan engine, written in the MATLAB/Simulink environment. The model has been tuned to capture the behavior of flight test data, and is capable of running at any point in the flight envelope [up to 40,000 ft (approximately equals 12,200 m) and Mach 0.8]. In addition to the open-loop engine, the simulation includes a controller whose architecture is representative of that found in industry. C-MAPSS40k fills the need for an easy-to-use, realistic, transient simulation of a medium-size commercial turbofan engine with a representative controller. It is a detailed component level model (CLM) written in the industry-standard graphical MATLAB/Simulink environment to allow for easy modification and portability. At the time of this reporting, no other such model exists in the public domain.

  9. In situ 40K-40Ca ‘double-plus’ SIMS dating resolves Klokken feldspar 40K-40Ar paradox

    NASA Astrophysics Data System (ADS)

    Harrison, T. Mark; Heizler, Matthew T.; McKeegan, Kevin D.; Schmitt, Axel K.

    2010-11-01

    The 40K- 40Ca decay system has not been widely utilized as a geochronometer because quantification of radiogenic daughter is difficult except in old, extremely high K/Ca domains. Even these environments have not heretofore been exploited by ion microprobe analysis due to the very high mass resolving power (MRP) of 25,000 required to separate 40K + from 40Ca +. We introduce a method that utilizes doubly-charged K and Ca species which permits isotopic measurements to be made at relatively low MRP (~ 5000). We used this K-Ca 'double-plus' approach to address an enduring controversy in 40Ar/ 39Ar thermochronology revolving around exsolved alkali feldspars from the 1166 Ma Klokken syenite (southern Greenland). Ion microprobe 40K- 40Ca analysis of Klokken samples reveal both isochron and pseudoisochron behaviors that reflect episodic isotopic and chemical exchange of coarsely exsolved perthites and a near end-member K-feldspar until ≤ 719 Ma, and perhaps as late at ~ 400 Ma. Feldspar microtextures in the Klokken syenite evolved over a protracted interval by non-thermal processes (fluid-assisted recrystallization) and thus this sample makes a poor model from which to address the general validity of 40Ar/ 39Ar thermochronological methodologies.

  10. Rapid determination of 226Ra in environmental samples

    SciTech Connect

    Maxwell, Sherrod L.; Culligan, Brian K.

    2012-02-04

    A new rapid method for the determination of {sup 228}Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/ Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine {sup 228}Ra in solid samples (via {sup 228}Ac) , radiochemical methods that employ gas flow proportional counting techniques typically provide lower MDA (Minimal Detectable Activity) levels for the determination of {sup 228}Ra in water samples. Most radiochemical methods for {sup 228}Ra collect and purify {sup 228}Ra and allow for {sup 228}Ac daughter ingrowth for ~36 hours. In this new SRNL/EBL approach, {sup 228}Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 hours so that {sup 228}Ra assay results on water samples can be achieved in < 6 hours. The method uses a rapid calcium carbonate precipitation enhanced with a small amount of phosphate added to enhance chemical yields (typically >90%), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. {sup 228}Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify {sup 228}Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and {sup 90}Y. La is used to determine {sup 228}Ac chemical yield via ICP-MS, but {sup 133}Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.

  11. Low level measurements of natural radionuclides in soil samples around a coal-fired power plant

    NASA Astrophysics Data System (ADS)

    Rosner, G.; Bunzl, K.; Hötzl, H.; Winkler, R.

    1984-06-01

    To detect a possible contribution of airborne radioactivity from stack effluents to the soil radioactivity, several radionuclides in the soil around a coal-fired power plant have been determined. A plant situated in a rural region of Bavaria was selected to minimize contributions from other civilisatory sources. The soil sampling network consisted of 5 concentric circles with diameters between 0.4 and 5.2 km around the plant, 16 sampling points being distributed regularly on each circle. Radiochemical analysis techniques for 210Pb and 210Po in soil samples of several grams had to be developed. They include a wet dissolution procedure, simultaneous precipitation of lead and polonium as the sulfides, purification via lead sulfate, counting of the lead as the chromate in a low-level beta counter and alpha spectrometric determination of the 210Po in a gridded ionization chamber. The 238U, 226Ra, 232Th and 40K were counted by low level gamma spectrometry. Specific activities found were in the range of 0.7 to 2.0 pCi g -1 for 210Pb and 0.3 to 1.6 pCi g -1 for 226Ra. The distribution patterns of 210Po and 210Pb around the plant were found to be similar. They were different, however, from that of 226Ra. The highest 210Pb/ 226Ra activity ratio was 3.9 at a distance of 0.76 km SSE from the plant. Nevertheless, the evidence is not considered to be sufficient to attribute these observations unambiguously to plant releases.

  12. Natural Radioactivity In Poultry Rations And DCP For Bovine Nutrition

    NASA Astrophysics Data System (ADS)

    Luz-Filho, Isaias V.; Scheibel, Viviane; Appoloni, Carlos R.

    2011-08-01

    The aim of this study is to determine the level of radioactivity present in samples of poultry rations and dicalcium phosphate (DCP) used for cattle feed. Knowledge of these levels is of fundamental importance, because part of this radioactivity will possibly be transferred to humans. The radiation found in such samples is due to the presence of radioactive series of 238U and 232Th and 40K. Measurements were performed with a 66% HPGe detector at the Laboratory of Applied Nuclear Physics, State University of Londrina. The measured samples were commercialized in Londrina, Brazil, in the second half of 2007. The accommodation recipient of the samples was a 1 L Marinelli beaker. Poultry rations were divided into two types: for young chickens and adult chickens. Among these, the ration for adult chickens showed the highest values for the activities of 226Ra and 228Ra, 0.23±0.17 and 0.493±0.091 Bq/kg respectively. But the ration for young chickens showed the highest activity for the 40K, 304±15 Bq/kg. The DCP sample showed a much higher value for the series of 238U and 232Th, 83±26 and 7.79±0.70 Bq/kg, respectively. However, the 40K activity in this sample was about 5 or 6 times lower than samples for poultry feed, reaching 46.6±2.8 Bq/kg.

  13. Natural radioactivity in cultivated land in the vicinity of a phosphate fertilizer plant in Nigeria

    NASA Astrophysics Data System (ADS)

    Okeji, Mark C.; Agwu, Kenneth K.; Idigo, Felicitas U.

    2012-12-01

    Natural radioactivity in soil and vegetable samples in cultivated land in the vicinity of an active phosphate fertilizer plant in Kaduna, Nigeria was carried out to assess the potential radiological impact of the plant on its immediate environment. The activity counting was carried out using sodium iodide gamma spectrometry. The annual committed effective dose for two vegetables in the farmlands due to uranium (238U) and thorium (232Th) was assessed. The mean activity concentration of radionuclides in the soil samples ranges from 20.5±7.3 to 31.6±4.1 Bq kg-1 for 226Ra, 19.6±1.6 to 53.2±3.7 Bq kg-1 for 232Th and 203.9±6.3 to 253.6±9.5 Bq kg-1 for 40K. The annual intake of 238U and 232Th from consumption of okra were 1.9 Bq kg-1 and 5.22 Bq kg-1 and for tomatoes 2.66 Bq kg-1 and 5.1 Bq kg-1 respectively. The committed effective doses from consumption of okra and tomatoes were 0.1 μSv y-1 and 0.12 μSv y-1 respectively.

  14. Natural radioactivity distribution and gamma radiation exposure of beach sands close to Kavala pluton, Greece

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Argyrios; Koroneos, Antonios; Christofides, Georgios; Stoulos, Stylianos

    2015-10-01

    This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along the beaches of Kavala being adjacent to the rock-types of the Kavala pluton. These ranged from 14-940, 16-1710, 26- 4547, 27-4488 and 194-1307 Bq/kg respectively, representing the highest values of natural radioactivity measured in sediments of Greece. The (%wt.) heavy magnetic (HM) (allanite, amphibole, mica, clinopyroxene, magnetite and hematite) fraction, the heavy non-magnetic (HNM) (monazite, zircon, titanite and apatite) fraction and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The heavy fractions seem to control the activity concentrations of 238U and 232Th of all the samples, showing some local differences in the main 238U and 232Th mineral carrier. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The annual equivalent dose varies between 0.01 and 0.35 mSv y-1 for tourists and from 0.03 to 1.48 mSv y-1 for local people working on the beach.

  15. Natural radioactivity levels (K, Th and Ra) in some areas of Punjab, India

    NASA Astrophysics Data System (ADS)

    Sabharwal, Arvind D.; Bhupinder, Singh; Kumar, Sanjeev; Singh, Surinder

    2012-04-01

    Radioactivity, natural and man-made, is omnipresent in the earth's crust in different amounts. Natural radioactive materials under certain conditions can reach hazardous radiological levels. So, it becomes necessary to study the natural radioactivity levels in soil to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. 226Ra, 232Th and 40K analysis has been carried out in soil samples collected from some areas of Punjab, India using gamma-ray spectrometry. Phe technique of gamma ray spectrometry was applied using high purity germanium gamma-ray detector and a PC based MCA. Radium equivalent activities are calculated for the analyzed samples to assess radiation hazards arising due to the use of these soil samples in construction of dwellings. Phe measured activity in the soil ranges from 23.17 to 57.87 Bq kg-1, 59.03 to 160.40 Bq kg-1 and 228.06 to 501.03 Bq kg-1 for 226Ra, 232Ph and 40K with mean values of 37.93, 84.47 and 351.17Bqkg-1 respectively. It has been observed that on the average the outdoor terrestrial gamma air absorbed dose rate is about 84.65nGyh-1.

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

    PubMed

    Ravisankar, R; Vanasundari, K; Suganya, M; Raghu, Y; Rajalakshmi, A; Chandrasekaran, A; Sivakumar, S; Chandramohan, J; Vijayagopal, P; Venkatraman, B

    2014-02-01

    Using γ spectrometry, the concentration of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K 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 (226)Ra distribution in building materials is controlled by the variation of the (40)K 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. PMID:24412972

  17. Natural radioactivity and effective dose due to the bottom sea and estuaries marine animals in the coastal waters around Peninsular Malaysia.

    PubMed

    Khandaker, M U; Olatunji, M A; Shuib, K S K; Hakimi, N A; Nasir, N L M; Asaduzzaman, Kh; Amin, Y M; Kassim, H A

    2015-11-01

    Malaysia is among the countries with the highest fish consumption in the world and relies on seafood as a main source of animal protein. Thus, the radioactivity in the mostly consumed marine animals such as fishes, crustaceans and molluscs collected from the coastal waters around Peninsular Malaysia has been determined to monitor the level of human exposure by natural radiation via seafood consumption. The mean activity concentrations of naturally occurring radionuclides (226)Ra ((238)U), (228)Ra ((232)Th) and (40)K ranged from 0.67 ± 0.19 Bq kg(-1) (Perna viridis) to 1.20 ± 0.70 Bq kg(-1) (Rastrelliger), from 0.19 ± 0.17 Bq kg(-1) (Teuthida) to 0.82 ± 0.67 Bq kg(-1) (Caridea) and from 34 ± 13 Bq kg(-1) (Caridea) to 48 ± 24 Bq kg(-1) (Teuthida), respectively. The mean annual committed effective dose due to the individual radionuclides shows an order of (228)Ra > (226)Ra > (40)K in all marine samples. The obtained doses are less than the global internal dose of 290 µSv y(-1) set by the United Nations Scientific Committee on the Effects of Atomic Radiation, discarding any significant radiological risks to the populace of Peninsular Malaysia. PMID:25956784

  18. Treatment of phosphogypsum waste produced from phosphate ore processing.

    PubMed

    El-Didamony, H; Gado, H S; Awwad, N S; Fawzy, M M; Attallah, M F

    2013-01-15

    Phosphogypsum (PG), primary byproduct from phosphoric acid production, is accumulated in large stockpiles and occupies vast areas of land. Phosphogypsum is a technologically enhanced naturally occurring radioactive material (TE-NORM) that contains radionuclides from (238)U and (232)Th decay series which are of most radio-toxicity. The reduction in concentration of radionuclides content from PG was based on leaching of (226)Ra, (210)Pb, (238)U and (40)K using tri-butyl phosphate (TBP) and tri-octyl phosphine oxide (TOPO) in kerosene. The factors which affect the leaching process such as contact time, concentration of the solvent and temperature were optimized. Based on the experimental results, about 92.1, 88.9, 83.4, 94.6% of (226)Ra, (210)Pb, (238)U and (40)K respectively were successfully removed from the PG. The reduction in the concentration of radionuclides was accompanied by reduction in the concentration of rare earth elements (∑REE) equals to 80.1%. Using the desired organic extractant under optimum conditions for treatment of the PG waste leads to obtain a decontaminated product that can be safely used in many industrial applications. PMID:23195600

  19. Estimates of the occupational exposure to tenorm in the phosphoric acid production plant in Iran.

    PubMed

    Fathabadi, N; Vasheghani Farahani, M; Moradi, M; Hadadi, B

    2012-09-01

    Phosphate rock is used world wide for manufacturing phosphoric acid and several chemical fertilisers. It is known that the phosphate rock contains various concentrations of uranium, thorium, radium and their daughters. The subject of this study is the evaluation of the radiation exposure to workers in the phosphoric acid production plant due to technologically enhanced naturally occurring radioactive materials that can result from the presence of naturally occurring radioactive materials in phosphate ores used in the manufacturing of phosphoric acid. Radiation exposure due to direct gamma radiation, dust inhalation and radon gas has been investigated and external and internal doses of exposed workers have been calculated. Natural radioactivity due to (40)K, (226)Ra and (232)Th have been measured in phosphate rock, phosphogypsum, chemical fertilisers and other samples by gamma spectrometry system with a high-purity germanium. The average concentrations of (226)Ra and (40)K observed in the phosphate rock are 760 and 80 Bq kg(-1), respectively. Annual effective dose from external radiation had a mean value of ∼0.673 mSv y(-1). Dust sampling revealed greatest values in the storage area. The annual average effective dose from inhalation of long-lived airborne was 0.113 mSv y(-1). Radon gas concentrations in the processing plant and storage area were found to be of the same value as the background. In this study the estimated annual effective doses to workers were below 1 mSv y(-1). PMID:22361352

  20. Response of soil microorganisms to radioactive oil waste: results from a leaching experiment

    NASA Astrophysics Data System (ADS)

    Galitskaya, P.; Biktasheva, L.; Saveliev, A.; Ratering, S.; Schnell, S.; Selivanovskaya, S.

    2015-01-01

    Oil wastes produced in large amounts in the processes of oil extraction, refining, and transportation are of great environmental concern because of their mutagenicity, toxicity, high fire hazardousness, and other properties. About 40% of these wastes contain radionuclides; however, the effects of oil products and radionuclides on soil microorganisms are frequently studied separately. The toxicity and effects on various microbial parameters of raw waste (H) containing 575 g of total petroleum hydrocarbons (TPH) kg-1 waste, 4.4 kBq kg-1 of 226Ra, 2.8 kBq kg-1 of 232Th, and 1.3 kBq kg-1 of 40K and its treated variant (R) (1.6 g kg-1 of TPH, 7.9 kBq kg-1 of 226Ra, 3.9 kBq kg-1 of 232Th, and 183 kBq kg-1 of 40K) were estimated in a leaching column experiment to separate the effects of hydrocarbons from those of radioactive elements. The disposal of H waste samples on the soil surface led to an increase of the TPH content in soil: it became 3.5, 2.8, and 2.2 times higher in the upper (0-20 cm), middle (20-40 cm), and lower (40-60 cm) layers respectively. Activity concentrations of 226Ra and 232Th increased in soil sampled from both H- and R-columns in comparison to their concentrations in control soil. The activity concentrations of these two elements in samples taken from the upper and middle layers were much higher for the R-column compared to the H-column, despite the fact that the amount of waste added to the columns was equalized with respect to the activity concentrations of radionuclides. The H waste containing both TPH and radionuclides affected the functioning of the soil microbial community, and the effect was more pronounced in the upper layer of the column. Metabolic quotient and cellulase activity were the most sensitive microbial parameters as their levels were changed 5-1.4 times in comparison to control ones. Changes of soil functional characteristics caused by the treated waste containing mainly radionuclides were not observed. PCR-SSCP (polymerase chain

  1. Spatial distribution and risk assessment of radionuclides in soils around a coal-fired power plant: A case study from the city of Baoji, China

    SciTech Connect

    Dai Lijun; Wei Haiyan . E-mail: yuxidlj@stu.snnu.edu.cn; Wang Lingqing

    2007-06-15

    Coal burning may enhance human exposure to the natural radionuclides that occur around coal-fired power plants (CFPP). In this study, the spatial distribution and hazard assessment of radionuclides found in soils around a CFPP were investigated using statistics, geostatistics, and geographic information system (GIS) techniques. The concentrations of {sup 226}Ra, {sup 232}Th, and {sup 40}K in soils range from 12.54 to 40.18, 38.02 to 72.55, and 498.02 to 1126.98 Bq kg{sup -1}, respectively. Ordinary kriging was carried out to map the spatial patterns of radionuclides, and disjunctive kriging was used to quantify the probability of radium equivalent activity (Ra{sub eq}) higher than the threshold. The maps show that the spatial variability of the natural radionuclide concentrations in soils was apparent. The results of this study could provide valuable information for risk assessment of environmental pollution and decision support.

  2. Natural radionuclide analysis in chattarpur area of southeastern coastal area of Odisha, India

    NASA Astrophysics Data System (ADS)

    Rautela, Bhagwat; Gusain, Gurupad; Yadav, Manjulata; Sahoo, Sarat; Tokonami, Shinji; Ramola, Rakesh

    2013-08-01

    The energy released in a spontaneous decay process of natural radionuclides is the main source of the total radiation dose to human beings. Natural radionuclides are widely distributed in soil, rocks, air, and groundwater. In present investigation, the analysis of terrestrial radionuclides such as 226Ra, 232Th, and 40K in soil and sand of Chattarpur area of southeastern coast of Odisha has been carried out using NaI(Tl) gamma ray detector. The higher activity concentrations of naturally occurring radionuclides have been reported from the study area. The gamma radiationdose originating from the terrestrial radionuclides was found to vary from 95 to 1813 nGy/h with an average of 700 nGy/h. This study is important to generate a baseline data of radiation exposure in the area. Health hazard effects due to natural radiation exposure are discussed in details.

  3. Natural radioactivity in sand used in thermal therapy at the Red Sea Coast.

    PubMed

    El-Arabi, A M

    2005-01-01

    The development of climatotherapy in Safaga opens the field of medical tourism in Egypt, in order to detect any harmful radiation that would affect the patients during treatment and is becoming important economic resource. Studies and survey of natural radiation and radioactivity in upper Egypt conducted since 1990, included monitoring of the concentration of natural radionuclides in environmental samples. The results of the study reveals that, for all sand samples, the mean activity concentration of 40K (618+/-122-548+/-82 Bq kg(-1)) are much higher than that of both 226Ra (25.3+/-14-20.6+/-10 Bq kg(-1)) and 232Th (21.4+/-10-22.4+/-10 Bq kg(-1)). Different radiation hazard indices were calculated, the radiation dose to which workers are subjected is not negligible (26.5-50.9 nGy h(-1)), although depending on the inhalation of dust. PMID:15748657

  4. Natural Radioactivity of Boron Added Clay Samples

    NASA Astrophysics Data System (ADS)

    Akkurt, I.; ćanakciı, H.; Mavi, B.; Günoǧlu, K.

    2011-12-01

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of diferent fields especially in dermatology application. Using clay such a field it is important to measure its natural radioacitivty. Thus the purpose of this study is to measure 226Ra, 232Th and 40K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3″×3″ NaI(Tl) detector. From the measured activity the radium equivalent activities (Raeq), external hazard index (Hex), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  5. A new Certified Reference Material for radionuclides in Irish sea sediment (IAEA-385).

    PubMed

    Pham, M K; Sanchez-Cabeza, J A; Povinec, P P; Andor, K; Arnold, D; Benmansour, M; Bikit, I; Carvalho, F P; Dimitrova, K; Edrev, Z H; Engeler, C; Fouche, F J; Garcia-Orellana, J; Gascó, C; Gastaud, J; Gudelis, A; Hancock, G; Holm, E; Legarda, F; Ikäheimonen, T K; Ilchmann, C; Jenkinson, A V; Kanisch, G; Kis-Benedek, G; Kleinschmidt, R; Koukouliou, V; Kuhar, B; Larosa, J; Lee, S-H; Lepetit, G; Levy-Palomo, I; Liong Wee Kwong, L; Llauradó, M; Maringer, F J; Meyer, M; Michalik, B; Michel, H; Nies, H; Nour, S; Oh, J-S; Oregioni, B; Palomares, J; Pantelic, G; Pfitzner, J; Pilvio, R; Puskeiler, L; Satake, H; Schikowski, J; Vitorovic, G; Woodhead, D; Wyse, E

    2008-11-01

    A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ((40)K, (137)Cs, (226)Ra, (228)Ra, (230)Th, (232)Th, (234)U, (238)U, (238)Pu, (239+240)Pu and (241)Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ((90)Sr, (210)Pb((210)Po), (235)U, (239)Pu, (240)Pu and (241)Pu). Results for less frequently reported radionuclides ((60)Co, (99)Tc, (134)Cs, (155)Eu, (224)Ra and (239)Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes. PMID:18513984

  6. Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea).

    PubMed

    Pham, M K; Sanchez-Cabeza, J A; Povinec, P P; Arnold, D; Benmansour, M; Bojanowski, R; Carvalho, F P; Kim, C K; Esposito, M; Gastaud, J; Gascó, C L; Ham, G J; Hegde, A G; Holm, E; Jaskierowicz, D; Kanisch, G; Llaurado, M; La Rosa, J; Lee, S-H; Liong Wee Kwong, L; Le Petit, G; Maruo, Y; Nielsen, S P; Oh, J-S; Oregioni, B; Palomares, J; Pettersson, H B L; Rulik, P; Ryan, T P; Sato, K; Schikowski, J; Skwarzec, B; Smedley, P A; Tarján, S; Vajda, N; Wyse, E

    2006-01-01

    A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units. PMID:16549351

  7. Assessment of natural radioactivity and associated radiation hazards in some building materials used in Kilpenathur, Tiruvannamalai dist, Tamilnadu, India

    SciTech Connect

    Raghu, Y.; Harikrishnan, N.; Ravisankar, R.; Chandrasekaran, A.

    2015-08-28

    The present study aimed to measure the radioactivity concentration of naturally occuring radionuclides in the locally used building materials from Kilpenthaur, Tiruvannmalai Dist, Tamilnadu, India. This study will also evaluate the radiation hazard arising due to the use of these materials in the construction of dwellings. The concentrations of natural radionuclides {sup 226}Ra, {sup 232}Th and {sup 40}K in five types of building materials have been measured by gamma spectrometry using NaI (Tl) 3” x 3”detector. The estimated radium equivalent activities (Ra{sub eq}), indoor absorbed gamma dose rate (D{sub R}), annual effective dose rate (H{sub R}) and the external hazard indexes(H{sub ex}) were lower than the recommended safe limit and are comparable with results from similar studies conducted in other countries. Therefore, the use of these building material samples under investigation in the construction of dwellings is considered to be safe for inhabitants.

  8. Radioactivity and heavy metal concentrations of some commercial fish species consumed in the Black Sea Region of Turkey.

    PubMed

    Korkmaz Görür, F; Keser, R; Akçay, N; Dizman, S

    2012-04-01

    Marine fish is an important daily diet item for the people of Turkey. The Black Sea Region of Turkey was contaminated by the Chernobyl accident in 1986, a comprehensive study was planned and carried out to determine the radioactivity levels ((226)Ra, (232)Th, (40)K and (137)Cs) and heavy metal concentrations (As, Mn, Fe, Cr, Ni, Zn, Cu and Pb) in four of the most common fish species: Engraulis encrasicholus (anchovy), Oncorhynchus mykiss (trout), Trachurus mediterranus (bluefin) and Merlangius merlangus (whiting) samples collected from eight stations in the Black Sea Region of Turkey during 2010. The dose due to consumption of fish by the public was estimated and it was shown that this dose imposes no threat to human healthy. The concentrations of heavy metal are below the daily intake recommended by the international organizations. PMID:22225706

  9. Measurement of radioactivity levels and assessment of radioactivity hazards of soil samples in Karaman, Turkey.

    PubMed

    Agar, O; Boztosun, I; Korkmaz, M E; Özmen, S F

    2014-12-01

    In this study, the levels of the natural and artificial radioactivity in soil samples collected from surrounding of Karaman in Turkey were measured. Activity concentrations of the concerned radionuclides were determined by gamma-ray spectrometry using a high-purity germanium detector with a relative efficiency of 40 % at 1.332 MeV. The results obtained for the (238)U series ((226)Ra, (214)Pb and (214)Bi), (232)Th series ((228)Ac), (40)K and fission product (137)Cs are discussed. To evaluate the radiological hazard of radioactivity in samples, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose and the external (Hex) and internal hazard index (Hin) were calculated and presented in comparison with the data collected from different areas in the world and Turkey. PMID:24587487

  10. Natural and artificial radionuclide measurements and radioactivity assessment of soil samples in eastern Sichuan province (China).

    PubMed

    Wang, Zhonghai; He, Jun; Du, Yu; He, Yang; Li, Zhiqian; Chen, Zhihua; Yang, Chaowen

    2012-07-01

    The activity concentrations of natural and artificial radionuclides were measured in the eastern region of Sichuan province (China). One hundred and ninety-three soil samples from this region were collected and analysed by high-purity germanium gamma spectrometry. The measured results show that the average radioactivity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs in the soil samples are 26, 49, 440 and 6 Bq kg(-1), respectively. The calculated average radium equivalent activity is 130 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1). The absorbed dose rate and annual effective dose are 60 nGy h(-1) and 74 µSv, respectively. This is the first time the absorbed dose rate in the east region of Sichuan has been mapped. Overall, the environmental radiation background is greater in the southern part of the area studied than in the northern. PMID:22128351

  11. Total half-lives for selected nuclides

    SciTech Connect

    Holden, N.E.

    1989-01-01

    Measurements of the half-lives of {sup 3}H, {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 40}K, {sup 39}Ar, {sup 53}Mn, {sup 87}Rb, {sup 92}Nb, {sup 129}I, {sup 138}La, {sup 147}Sm, {sup 176}Lu, {sup 174}Hf, {sup 180}Ta, {sup 187}Re, {sup 186}Os, {sup 190}Pt, {sup 204}Pb, {sup 210}Pb, {sup 210}Po, {sup 222}Rn, {sup 224}Th, {sup 226}Ra, {sup 227}Ac, {sup 228}Ra, {sup 228}Th, {sup 230}Th, {sup 232}Th, {sup 231}Pa have been compiled and evaluated. The effect of the {sup 14}C half-life value on carbon dating ages is discussed as well as the stability of {sup 204}Pb. 237 refs., 30 tabs.

  12. Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

    NASA Astrophysics Data System (ADS)

    Priharti, W.; Samat, S. B.; Yasir, M. S.

    2015-09-01

    The radionuclides of 226Ra, 232Th and 40K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10-3 (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

  13. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca

    PubMed Central

    Khandaker, M. U.; Asaduzzaman, Kh.; Nawi, S. M.; Usman, A. R.; Amin, Y. M.; Daar, E.; Bradley, D. A.; Ahmed, H.; Okhunov, A. A.

    2015-01-01

    The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrouding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance. PMID:26075909

  14. Correlations of natural radionuclides in soil with those in sediment from the Danube and nearby irrigation channels.

    PubMed

    Krmar, M; Varga, E; Slivka, J

    2013-03-01

    The correlation between activity concentrations of some natural radionuclides ((238)U, (226)Ra, (232)Th, (40)K) measured in soil and in sediment taken from the Danube River and nearby irrigation channels was studied. The soil samples were collected from the northern part of Serbia and the sediment from the Serbian part of the Danube River and from the surrounding irrigation channels. The correlation between (238)U and other natural radionuclides in irrigation channel sediments was not as good as in the Danube. One of the possible explanations for this weak correlation can be the different chemical dynamics of (238)U in the irrigation channel sediment or changes of the (238)U activity concentration in irrigation channel sediment due to some human activities. The evaluation of ratios of activity concentrations of some natural radionuclides could be a more sensitive method for the determination of contaminant, rather than the straightforward analysis of activity concentrations. PMID:22244685

  15. Study of natural radioactivity and the state of radioactive disequilibrium in U-series for rock samples, North Eastern Desert, Egypt.

    PubMed

    El-Dine, Nadia Walley

    2008-01-01

    Twenty rock samples collected from North Eastern Desert in Egypt have been investigated. Natural radionuclide contents have been measured by gamma-ray spectrometry employing a shielded HPGe detector. The activities of (238)U, (232)Th and (40)K have been determined in Bq/kg dry weight. The absorbed dose rate of gamma radiation ranged from 100.48 to 22,140.53 nGy/h. The representative external hazard index values (H(ex)) for the corresponding samples were estimated. In the present work, the state of radioactive disequilibrium in the U-series at Wadi Baligh area was studied. The activity ratios between (226)Ra/(214)Pb and (214)Pb/(214)Bi were measured. The thorium-to-uranium concentration ratios (Clark value) were also estimated. PMID:17869529

  16. Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

    SciTech Connect

    Priharti, W.; Samat, S. B.; Yasir, M. S.

    2015-09-25

    The radionuclides of {sup 226}Ra, {sup 232}Th and {sup 40}K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10{sup −3} (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

  17. Radionuclides, heavy metals and fluorine incidence at Tapira phosphate rocks, Brazil, and their industrial (by) products.

    PubMed

    da Conceição, Fabiano Tomazini; Bonotto, Daniel Marcos

    2006-01-01

    Inorganic phosphate fertilizers may contain radionuclides, heavy metals and fluorine. This paper presents the possible environmental hazards from Tapira phosphate rocks and their (by) products (Brazil) utilized as phosphate fertilizers. The activity concentration of 238U, 234U, 226Ra and 40K in Tapira phosphate rocks is within the world range for these rock types. The 232Th activity concentration is higher than the mean reported in phosphate rocks. A value of 2184 nGy h(-1) was obtained for the exposure dose rate in Tapira phosphate deposit area, which is indicative of a high background radiation area. The flotation-separation process causes the incorporation of no more than 9%, 11% and 24% of radionuclides, heavy metals and fluorine, respectively, into the phosphate concentrate. The radionuclides and heavy metals existing in phosphate fertilizers applied in Brazilian crops according to the recommended rates, do not raise their concentration in soils to harmful levels. PMID:16099562

  18. A review of the nationwide proficiency test on natural radioactivity measurements by gamma spectrometry.

    PubMed

    Şahin, N K; Yeltepe, E; Yücel, Ü

    2016-03-01

    This study is the review of the first proficiency test on radioactivity measurement organized in Turkey by Sarayköy Nuclear Research and Training Center (SANAEM) of Turkish Atomic Energy Authority (TAEK) in 2013. The objective of the test was to determine (226)Ra, (232)Th and (40)K activity concentrations in natural soil samples using gamma-ray spectrometry. The bulk material consisting of uranium- and thorium-rich soil and sand was milled, mixed thoroughly and sieved. Homogeneity of the final mix was tested with 6 randomly taken samples. 16 proficiency test samples were distributed to 16 participating laboratories. 12 laboratories reported results. The results were evaluated on the accuracy and precision criteria adopted by the IAEA Proficiency Testing Group. The percentage of acceptable scores was 49%. Some recommendations have been provided to the laboratories to improve the quality of their results. It is planned to extend these proficiency tests periodically for various radionuclides in various matrices. PMID:26750585

  19. Natural radionuclide and radiological assessment of building materials in high background radiation areas of Ramsar, Iran

    PubMed Central

    Bavarnegin, Elham; Moghaddam, Masoud Vahabi; Fathabadi, Nasrin

    2013-01-01

    Building materials, collected from different sites in Ramsar, a northern coastal city in Iran, were analyzed for their natural radionuclide contents. The measurements were carried out using a high resolution high purity Germanium (HPGe) gamma-ray spectrometer system. The activity concentration of 226Ra, 232Th, and 40K content varied from below the minimum detection limit up to 86,400 Bqkg-1, 187 Bqkg-1, and 1350 Bqkg-1, respectively. The radiological hazards incurred from the use of these building materials were estimated through various radiation hazard indices. The result of this survey shows that values obtained for some samples are more than the internationally accepted maximum limits and as such, the use of them as a building material pose significant radiation hazard to individuals. PMID:23776313

  20. Natural Radioactivity of Boron Added Clay Samples

    SciTech Connect

    Akkurt, I.; Guenoglu, K.; Canakcii, H.; Mavi, B.

    2011-12-26

    Clay, consisting fine-grained minerals, is an interesting materials and can be used in a variety of different fields especially in dermatology application. Using clay such a field it is important to measure its natural radioactivity. Thus the purpose of this study is to measure {sup 226}Ra, {sup 232}Th and {sup 40}K concentration in clay samples enriched with boron. Three different types of clay samples were prepared where boron is used in different rate. The measurements have been determined using a gamma-ray spectrometry consists of a 3''x3'' NaI(Tl) detector. From the measured activity the radium equivalent activities (Ra{sub eq}), external hazard index (H{sub ex}), absorbed dose rate in air (D) and annual effective dose (AED) have also been obtained.

  1. Certified Reference Material IAEA-446 for radionuclides in Baltic Sea seaweed.

    PubMed

    Pham, M K; Benmansour, M; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gwynn, J P; Harms, A V; Hrnecek, E; Ibanez, F L; Ilchmann, C; Ikaheimonen, T; Kanisch, G; Kloster, M; Llaurado, M; Mauring, A; Møller, B; Morimoto, T; Nielsen, S P; Nies, H; Norrlid, L D R; Pettersson, H B L; Povinec, P P; Rieth, U; Samuelsson, C; Schikowski, J; Silobritiene, B V; Smedley, P A; Suplinska, M; Vartti, V-P; Vasileva, E; Wong, J; Zalewska, T; Zhou, W

    2014-05-01

    A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The (40)K, (137)Cs, (234)U and (239+240)Pu radionuclides were certified for this material, and information values for 12 other radionuclides ((90)Sr, (99)Tc, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (235)U, (238)U, (239)Pu and (240)Pu) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes. PMID:24291528

  2. 40 kW Stirling engine for solid fuel

    SciTech Connect

    Carlsen, H.; Ammundsen, N.; Traerup, J.

    1996-12-31

    The external combustion in a Stirling engine makes it very attractive for utilization of solid fuels in decentralized combined heat and power (CHP) plants. Only few projects have concentrated on the development of Stirling engines specifically for biomass. In this project a Stirling engine has been designed primarily for utilization of wood chips. Maximum shaft power is 40 kW corresponding to an electric output of 36 kW. Biomass needs more space in the combustion chamber compared to gas and liquid fuels, and a large heat transfer area is necessary. The design of the new Stirling engine has been adapted to the special demands of combustion of wood chips, resulting in a large engine compared to engines for gas or liquid fuels. The engine has four-cylinders arranged in a square. The design is made as a hermetic unit, where the alternator is built into the pressurized crankcase so that dynamic seals are avoided. Grease lubricated bearings are used in a special designed crank mechanism, which eliminates guiding forces on the pistons Helium is used as working gas at 4 MPa mean pressure. The first test of the 40 kW engine with natural gas as fuel has been made in the laboratory, and the results are in agreement with predicted results from simulation programs. The wood chips combustion system has been tested for some time with very promising results. When the laboratory test of the engine is finished, the test of the complete system will be initiated. The paper describes the engine and results from the test program. Expectations to maintenance and operation problems are also discussed.

  3. Natural radionuclide concentrations in granite rocks in Aswan and Central-Southern Eastern Desert, Egypt and their radiological implications.

    PubMed

    Issa, Shams A M; Uosif, M A M; Abd el-Salam, L M

    2012-07-01

    Different types of granites, used extensively in local construction, were collected from five localities in Egypt, namely: Abu Ziran (Central Eastern Desert), Gabal El Maesala (Aswan) and three areas from Wadi Allaqi, (Gabal Abu Marw, Gabal Haumor and Gabal um Shalman), in the South Eastern Desert. Granite samples were studied radiologically, petrographically and geochemically. The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples by using gamma spectrometry [NaI (Tl) 3'×3']. The activity concentrations of (226)Ra, (232)Th and (40)K in the selected granite samples ranged from 9±0.5 to 111±7, 8±1 to 75±4 and 100±6 to 790±40 Bq kg(-1), respectively. The external hazard index (H(ex)), absorbed dose and annual effective dose rate were evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. The calculated radium equivalents were lower than the values recommended for construction materials (370 Bq kg(-1)). The excess lifetime cancer risks were also calculated. Petrographically, the granites studied are varied in the form of potash-feldspar, quartz, plagioclase, mica and hornblende. The accessory minerals are zircon, apatite and allanite. Geochemically, the chemical composition of the granite is studied especially for major oxides. They are characterized to have SiO(2), K(2)O, Na(2)O and Al(2)O(3) with depletion in CaO, MgO, TiO(2) and P(2)O(5). PMID:22147926

  4. Radon exhalation and natural radiation exposure in low ventilated rooms

    NASA Astrophysics Data System (ADS)

    Abdallah, A. M.; Mohery, M.; Yaghmour, Saud J.; Alddin, S. H.

    2012-11-01

    In the first part of this paper, the influence of radon (222Rn) exhalation rate from walls and air exchange upon its concentration in room air was considered using a simple mathematical room model. The exhalation rates have been determined in ten low ventilated rooms of ten villas in Jeddah city (Western Province) of Saudi Arabia. An electroprecipitation method has been applied for the determination of the 222Rn gas concentration in these rooms. The mean 222Rn gas concentration was found to be 46.80±8.80 Bq m-3. The mean 222Rn exhalation rate was estimated to be 20.11±6.90 Bq m-2 h-1. The mean inhalation dose due to the exposure to 222Rn gas was calculated to be 1.18±2.30 mSv y-1. The second part of this paper deals with a study of natural radionuclide contents of samples collected from the building materials of these rooms under investigations in part one. Analyses were performed in Marinelli beakers with a gamma spectroscopy system to quantify radioactivity concentrations. The collected samples revealed the presence of the uranium-radium (226Ra) and thorium (232Th) radioisotopes as well as 40K. The mean activity concentration of 226Ra, 232Th and 40K was determined to be 48.30±5.08, 43.90±5.63 and 223.90±7.55 Bq kg-1, respectively. These activities amount to a radium equivalent (Raeq) of 125.96±15.90 Bq kg-1 and to a mean value of external hazard index (Hex) of 0.34±0.04.

  5. Assessment of natural radioactivity of sand used in Turkey.

    PubMed

    Cevik, U; Damla, N; Kobya, A I; Celik, N; Celik, A; Van, A A

    2009-03-01

    The natural radioactivity due to the presence of (226)Ra, (232)Th and (40)K in sand samples used as building materials in Turkey was measured by gamma spectrometry. The measured activity in the sand samples ranged from 17 to 97 Bq kg(-1), 10 to 133 Bq kg(-1) and 116 to 955 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The concentrations of these natural radionuclides were compared with the reported data for other countries. The radium equivalent activity (Ra(eq)), the external hazard index (H(ex)), the internal hazard index (H(in)), the indoor absorbed dose rate in air and the annual effective dose rate were evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. The Ra(eq) values of sand samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv yr(-1). This study shows that the measured sand samples do not pose any significant source of radiation hazard and are safe for use in building materials. Moreover, the experimental mass attenuation coefficients (mu/rho) of seven different sand samples were determined in the energy range 80-1332 keV photons by using the gamma ray transmission method. Experimental values of mass attenuation coefficient were compared with theoretical values obtained using the program XCOM. The calculated values and the experimental results of this work and the other results in the literature are found to be in good agreement. Chemical and structural analyses (XRD) of the sand samples were also undertaken. PMID:19225183

  6. Assessment of natural and anthropogenic radioactivity levels in rocks and soils in the environments of Juban town in Yemen

    NASA Astrophysics Data System (ADS)

    Abd El-mageed, A. I.; El-Kamel, A. H.; Abbady, A.; Harb, S.; Youssef, A. M. M.; Saleh, I. I.

    2011-06-01

    The natural radioactivities of 40K, 226Ra, and 232Th and the fallout of 137Cs in rock and soil samples collected around Juban town in Yemen (south west of Asia) were measured. Concentrations of radionuclides in samples were determined by gamma-ray spectrometer using HPGe detector with specially designed shield. The average radioactivity concentrations of 226Ra, 232Th, and 40K were determined expressed in Bq/kg. The results show that these radionuclides were present in concentrations of (53.6±4, 127±6.7, and 1742.8±62 Bq/kg), (55±4, 121±6.6, and 2341±78 Bq/kg), (212.8±8.7, 109 ±5.5, and 32.4±4.7 Bq/kg), and (32.1±3, 22.3±2.9 and 190.9±15 Bq/kg) for granite, gneiss, siltstone, and sandstone rocks, respectively. For soil the corresponding values were 44.4±4.5, 58.2±5.1, and 822.7±31 Bq/kg. Low deposits of 137Cs were noted in investigation area, where the activity concentrations ranged from 0.1±0.1 to 23.2±1.2 Bq/kg. Also the radiological hazard of the natural radionuclides content, radium equivalent activity, total dose rates, external hazard index, and gamma activity concentration index of the (rocks/soils) samples in the area under consideration were calculated. The data were discussed and compared with those given in the literature.

  7. Evaluation of radionuclides transfer from soil-to-edible flora and estimation of radiological dose to the Malaysian populace.

    PubMed

    Khandaker, Mayeen Uddin; Mohd Nasir, Noor Liyana; Asaduzzaman, Kh; Olatunji, Michael Adekunle; Amin, Yusoff Mohd; Kassim, Hasan Abu; Bradley, D A; Jojo, P J; Alrefae, Tareq

    2016-07-01

    Malaysia, a rapidly growing industrial country, is susceptible to pollution via large-scale industrial engagements and associated human activities. One particular concern is the potential impact upon the quality of locally resourced vegetables, foodstuffs that contain important nutrients necessary for good health, forming an essential part of the Malaysian diet. As a part of this, it is of importance for there to be accurate knowledge of radioactive material uptake in these vegetables, not least in respect of any public health detriment. Herein, using HPGe γ-ray spectrometry, quantification has been performed of naturally occurring radionuclides in common edible vegetables and their associated soils. From samples analyses, the soil activity concentration ranges (in units of Bq/kg) for (226)Ra, (232)Th and (40)K were respectively 1.33-30.90, 0.48-26.80, 7.99-136.5 while in vegetable samples the ranges were 0.64-3.80, 0.21-6.91, 85.53-463.8. Using the corresponding activities, the transfer factors (TFs) from soil-to-vegetables were estimated, the transfers being greatest for (40)K, an expected outcome given the essentiality of this element in support of vigorous growth. The TFs of (226)Ra and (232)Th were found to be in accord with available literature data, the values indicating the mobility of these radionuclides to be low in the studied soils. Committed effective dose and the associated life-time cancer risk was estimated, being found to be below the permissible limit proposed by UNSCEAR. Results for the studied media show that the prevalent activities and mobilities pose no significant threat to human health, the edible vegetables being safe for consumption. PMID:27085312

  8. Distribution of natural and anthropogenic radionuclides in beach sand samples from Mediterranean Coast of Turkey

    NASA Astrophysics Data System (ADS)

    Özmen, S. F.; Cesur, A.; Boztosun, I.; Yavuz, M.

    2014-10-01

    Following Fukushima Dai-ichi Nuclear Power Plant accident, a huge amount of radionuclides were released in atmosphere and ocean. It's impact on the environment is of great concern to the good of the public at large. In this regard environmental radioactivity monitoring such as external dose rate and radioactivity measurements in environmental samples has been carried out. For this purpose, several beach sand samples were collected from south coast of the Turkey in September 2011 and radioactivity concentrations of 226Ra (238U), 228Ac (232Th), 40K, 134Cs and 137Cs were determined by gamma spectrometry using a high-purity Germanium detector. The measured activity concentrations in beach sand samples ranged from 4.0±0.5 to 21.5±1.8 Bq/kg, 1.8±0.4 to 27.9±2.4 Bq/kg, 19.0±2.2 to 590.3±28.6 Bq/kg and 0.1±0.0 to 1.0±0.1 Bq/kg for 226Ra, 232Th, 40K and 137Cs, respectively. However there was no sign of 134Cs in the sample spectrum after Fukushima Dai-ichi Nuclear Power Plant accident. Hence we can safely conclude that there was no significant material transfer from Fukushima to Turkey. The other activities are in good agreement with the published results of neighboring areas. The absorbed gamma dose rate (D) and the annual effective dose (AED) of beach sand samples were below the world wide average implying that the radiation hazard is insignificant. The data presented in this study would also be very useful to determine the possible future effects of the nuclear power plant to the environment.

  9. Assessment of radiological health implicat from ambient environment in the Muar district, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; Alajerami, Yasser; Mhareb, Mohammad Hasan Abu; Aliyu, Abubakar Sadiq; Gabdo, Hamman Tukur; Garba, Nuraddeen Nasiru

    2014-10-01

    This study aims to obtain baseline data of environmental terrestrial radiation and to assess the corresponding health risk in the ambient environment in Muar District, Johor, Malaysia in view of the possible construction of nuclear power plant (NPP) in the future. The external gamma dose rate (GDR), measured using two portable survey meters, was 151 nGy h-1. The activity concentrations of 232Th, 226Ra, and 40K were determined using hyper pure germanium (HPGe) detector. The activity concentrations were varied from 11±1 to 583±18 Bq kg-1 for 232Th, 6±1 to 244±9 Bq kg-1 for 226Ra, and 13±6 to 830±13 Bq kg-1 for 40K. Various types of water samples were analyzed using a Low Background Alpha Beta Series 5 XLB instrument at Nuclear Malaysia (NM). Gross alpha activity concentrations in tap water varied from 3±1 mBq L-1 to 34±6 mBq L-1 and gross beta activity concentrations varied from 58±5 mBq L-1 to 709±39 mBq L-1 which were lower than the recommended value by Interim National Water Quality Standards for Malaysia (INWQS) and World Health Organization (WHO, 1993). The radiological health which are the annual effective dose equivalent, the collective effective dose, radium equivalent activity and external hazard index 0.220 mSv, 0.526×102 man Sv y-1, 359 Bq kg-1 and 0.969, respectively. The results were comparable to internationally recommended values and discussed accordingly.

  10. Natural radioactivity and external dose assessment of surface soils in Vietnam.

    PubMed

    Huy, N Q; Hien, P D; Luyen, T V; Hoang, D V; Hiep, H T; Quang, N H; Long, N Q; Nhan, D D; Binh, N T; Hai, P S; Ngo, N T

    2012-09-01

    In this study, natural radioactivity in surface soils of Vietnam and external dose assessment to human population, deduced from activities of (226)Ra, (232)Th and (40)K nuclides, were determined. From 528 soil samples collected in 63 provinces of Vietnam, including five centrally governed cities, the average activities were obtained and equal to 42.77 ± 18.15 Bq kg(-1) for (226)Ra, 59.84 ± 19.81 Bq kg(-1) for (232)Th and 411.93 ± 230.69 Bq kg(-1) for (40)K. The outdoor absorbed dose rates (OADRs) in air at 1 m above the ground level for 63 provinces were calculated, and their average value was 71.72 ± 24.72 nGy h(-1), with a range from 17.45 to 149.40 nGy h(-1). The population-weighted OADR of Vietnam was 66.70 nGy h(-1), which lies in the range of 18-93 nGy h(-1) found in the World. From the OADRs obtained, it was estimated that the outdoor annual effective dose and indoor annual effective dose to the population were 0.082  and 0.458 mSv, which are higher than the corresponding values 0.07 and 0.41 mSv, respectively, of the World. The radium equivalent activity Ra(eq) and the external hazard index H(ex) of surface soils of Vietnam are lower than the corresponding permissible limits of 370 Bq kg(-1) and 1, respectively. Therefore, soil from Vietnam is safe for the human population when it is used as a building material. PMID:22434923

  11. Radioactivity Levels and Gamma-Ray Dose Rate in Soil Samples from Kohistan (Pakistan) Using Gamma-Ray Spectrometry

    NASA Astrophysics Data System (ADS)

    Hasan, M. Khan; Ismail, M.; K., Khan; Akhter, P.

    2011-01-01

    The analysis of naturally occurring radionuclides (226Ra, 232Th and 40K) and an anthropogenic radionuclide 137Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium (HPGe) detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges from 24.72 to 78.48Bq·kg-1 for 226Ra, 21.73 to 75.28Bq·kg-1 for 232Th, 7.06 to 14.9Bq·kg-1 for 137Cs and 298.46 to 570.77Bq·kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq·kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report (370Bq·kg-1). Man-made radionuclide 137Cs is also present in detectable amount in all soil samples. Presence of 137Cs indicates that the samples in this remote area also receive some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.

  12. An evaluation of the level of naturally occurring radioactive material in soil samples along the Chao Phraya river basin

    NASA Astrophysics Data System (ADS)

    Santawamaitre, T.; Regan, P. H.; Bradley, D. A.; Matthews, M.; Malain, D.; Al-Sulaiti, H. A.

    2010-07-01

    The aim of this study was to evaluate the level of natural radioactivity in river sediments and riverbank surface soils collected along the Chao Phraya River and its tributaries in Thailand. The activity concentrations of radionuclides in 238U and 232Th decay chains as well as 40K in all samples have been determined by means of a gamma-ray spectrometry system using a hyper-pure germanium detector in a low background configuration. The ranges of specific activity for 226Ra, 232Th and 40K were found to be 15.2-67.0, 16.8-73.3 and 204.6-656.5 Bq kg -1, respectively. Additionally, evaluations have been made of the absorbed gamma dose rate in air and the annual effective dose equivalent from outdoor terrestrial gamma radiation in order to assess any excess radiological risk from agricultural usage of fertilizers. In this study, the absorbed dose rate was observed to vary from 30.5 to 102.6 nGy h -1 and the outdoor annual effective dose equivalent to range from 37.4 to 125.8 μSv yr -1.

  13. Natural radionuclide concentrations in two phosphate ores of east Algeria.

    PubMed

    Lakehal, Ch; Ramdhane, M; Boucenna, A

    2010-05-01

    Ore is considered as an important source of many elements such as the iron, phosphorus, and uranium. Concerning the natural radionuclides, their concentrations vary from an ore to other depending on the chemical composition of each site. In this work, two phosphate ores found in East of Algeria have been chosen to assess the activity concentration of natural radionuclides represented mainly by three natural radioactive series (238)U, (235)U and (232)Th, and the primordial radionuclide (40)K where they were determined using ultra-low background, high-resolution gamma-ray spectroscopy. The measured activity concentrations of radioactive series ranged from 6.2 +/- 0.4 to 733 +/- 33 Bq.kg(-1) for the (232)Th series, from 249 +/- 16 to 547 +/- 39 Bq.kg(-1) for the (238)U series, around 24.2 +/- 2.5 Bq.kg(-1) for the (235)U series, and from 1.4 +/- 0.2 to 6.7 +/- 0.7 Bq.kg(-1) for (40)K. To assess exposure to gamma radiation in the two ores, from specific activities of (232)Th, (40)K and (226)Ra, three indexes were determined: Radium equivalent (Ra(eq)), external and internal hazard indexes (H(ex) and H(in)), their values ranged from 831 +/- 8 to 1298 +/- 14 Bq.kg(-1) for Ra(eq), from 2.2 +/- 0.4 to 3.5 +/- 0.7 Bq.kg(-1) for H(ex), and from 4.2 +/- 0.7 to 4.5 +/- 0.7 Bq.kg(-1) for H(in). PMID:20303630

  14. Committed effective dose from naturally occuring radionuclides in shellfish

    NASA Astrophysics Data System (ADS)

    Khandaker, Mayeen Uddin; Wahib, Norfadira Binti; Amin, Yusoff Mohd.; Bradley, D. A.

    2013-07-01

    Recognizing their importance in the average Malaysian daily diet, the radioactivity concentrations in mollusc- and crustacean-based food have been determined for key naturally occuring radionuclides. Fresh samples collected from various maritime locations around peninsular Malaysia have been processed using standard procedures; the radionuclide concentrations being determined using an HPGe γ-ray spectrometer. For molluscs, assuming secular equilibrium, the range of activities of 238U (226Ra), 232Th (228Ra) and 40K were found to be 3.28±0.35 to 5.34±0.52, 1.20±0.21 to 2.44±0.21 and 118±6 to 281±14 Bq kg-1 dry weight, respectively. The respective values for crustaceans were 3.02±0.57 to 4.70±0.52, 1.38±0.21 to 2.40±0.35 and 216±11 to 316±15 Bq kg-1. The estimated average daily intake of radioactivity from consumption of molluscs are 0.37 Bq kg-1 for 238U (226Ra), 0.16 Bq kg-1 for 232Th (228Ra) and 18 Bq kg-1 for 40K; the respective daily intake values from crustaceans are 0.36 Bq kg-1, 0.16 Bq kg-1 and 23 Bq kg-1. Associated annual committed effective doses from molluscs are estimated to be in the range 21.3 to 34.7 μSv for 226Ra, 19.3 to 39.1 μSv for 228Ra and 17.0 to 40.4 μSv for 40K. For crustaceans, the respective dose ranges are 19.6 to 30.5 μSv, 22.0 to 38.4 μSv and 31.1 to 45.5 μSv, being some several times world average values.

  15. Natural radionuclides content and associated dose rates in fine-grained sediments from Patras-Rion sub-basins, Greece.

    PubMed

    Papaefthymiou, H V; Chourdakis, G; Vakalas, J

    2011-01-01

    The activity concentrations of the natural radionuclides (238)U, (226)Ra, (232)Th and (40)K were measured in soil samples collected from the Patras-Rion sub-basins (Southern Greece) and were found to be 28, 27, 30 and 483 Bq kg(-1), respectively. These values compare well with the average Greek and worldwide values for crustal soil and sedimentary rocks. The mean (226)Ra/(238)U activity ratio was close to 1, implying secular radioactive equilibrium in the uranium series. All soil samples have Ra(eq) values lower than the limit of 370 Bq kg(-1), indicating their safe use in brick production. The average annual terrestrial absorbed dose rate in air was 51±14 nGy h(-1), and the average annual effective dose 0.06±0.02 mSv y(-1), which is consistent with the average worldwide exposure to external terrestrial radiation outdoors (0.07 mSv y(-1)). Non-significant differences between soils with different age and depositional environments were found, which could be attributed to a common source of sediments. PMID:21059742

  16. Radiological hazards of TENORM in precipitated calcium carbonate generated as waste at nitrophosphate fertilizer plant in Pakistan.

    PubMed

    Javied, Sabiha; Akhtar, Nasim; Tufail, M

    2011-08-15

    The NORM (naturally occurring radioactive material) in phosphate rock is transferred as TENORM (technologically enhanced naturally occurring radioactive material) to phosphatic fertilizers and to the waste generated by the chemical processes. The waste generated at the NP (nitrophosphate) fertilizer plant at Multan in Pakistan is PCC (precipitated calcium carbonate). Thirty samples of the PCC were collected from the heaps of the waste near the fertilizer plant. Activity concentrations of radionuclides in the waste samples were measured by using the technique of gamma ray spectrometry consisting of coaxial type HPGe (high purity germanium) detector coupled with a PC (personal computer) based MCA (multichannel analyzer) through a spectroscopy amplifier. Activity concentrations of (226)Ra, (232)Th and (40)K in the waste samples were determined to be 273 ± 23 (173-398), 32 ± 4 (26-39) and 56 ± 5 (46-66) Bq kg(-1) respectively. The activity concentration of (226)Ra in the PCC waste was found to be higher than that in naturally occurring calcium carbonate (limestone and marble) and in worldwide soil. Radiological hazard was estimated from indoor and outdoor exposure to gamma rays from the PCC. Indoor annual effective dose was higher than 1 mSv. Potential radiological pollution in the environment from TENORM in the PCC has also been addressed. PMID:21612862

  17. The gamma dose assessment and pH correlation for various soil types at Batu Pahat and Kluang districts, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Johar, Saffuwan Mohamed; Embong, Zaidi; Tajudin, Saiful Azhar Ahmad

    2016-01-01

    An assessment of absorbed dose and radiation hazard index as well as its relationship with soil pH was performed in this study. The area was chosen due to its variety of soil types from the Alluvial and the Sedentary group. The radioactivity concentration levels and the soil acidity were measured using the Canberra GC3518 high pure germanium with a relative efficiency of 35% at 1.3 MeV and the Takemura Soil pH and Moisture Tester (DM15), respectively. Overall results show the Holyrood-Lunas soil of Alluvial group recorded the highest external terrestrial gamma radiation dose rate (TGRD) of 286.4±37.9 nGy h-1 and radioactivity concentrations of 78.1±8.9 Bq kg-1 (226Ra), 410.5±55.4 Bq kg-1 (232Th) and 56.4±8.8 Bq kg-1 (40K), respectively, while the Peat soil of Alluvial group recorded the lowest TGRD of 4.4±2.7 nGy h-1 and radioactivity concentrations of 4.8±1.7 Bq kg-1 (226Ra), 3.1±1.1 Bq kg-1 (232Th) and 6.1±2.0 Bq kg-1 (40K), respectively. The estimated mean outdoor annual effective dose, the mean radium equivalent activity (Req) and the mean external (Hext) and internal hazard index (Hint) associated with the alluvial and sedentary soil group were evaluated at 0.15 and 0.20 mSv, 280 and 364 Bq kg-1, Hext = 0.78 and 1.01, and Hint = 0.93 and 1.26, respectively. Correlation analysis between 238U, 232Th and 40K with soil pH level for alluvial group was r = +0.68, +0.48 and 0, respectively, while for sedentary soil, the Pearson's, r = -0.30, -0.90 and +0.14, respectively.

  18. Statistical analysis of the spatial distribution of radionuclides in soils around a coal-fired power plant in Spain.

    PubMed

    Charro, Elena; Pardo, Rafael; Peña, Víctor

    2013-10-01

    Coal-fired power-plants (CFPP) can be a source of contamination because the coal contains trace amounts of natural radionuclides, such as (40)K and (238)U, (232)Th and their decay products. These radionuclides can be released as fly ash from the CFPP and deposited from the atmosphere on the nearby top soils, therefore modifying the natural radioactivity background levels, and subsequently increasing the total radioactive dose received for the nearby population. In this paper, an area of 64 km(2) around the CFPP of Velilla del Río Carrión (Spain) has been studied by collecting 67 surface soil samples and measuring the activities of one artificial and six natural radionuclides by gamma spectrometry. The found results are similar to the background natural levels and ranged from 0 to 209 for (137)Cs, 11 to 50 for (238)U, 14 to 67 for (226)Ra, 29 to 380 for (210)Pb, 15 to 68 for (232)Th, 17 to 78 for (224)Ra, 97 to 790 for (40)K (all values in Bq kg(-1)). Besides the classical radiochemical tools, Analysis of Variance (ANOVA), Principal Component Analysis (PCA), Hierarchical Clustering Analysis (HCA), and kriging mapping have been used to the experimental dataset, allowing us to find the existence of two different models of spatial distribution around the CFPP. The first, followed by (238)U, (226)Ra, (232)Th, (224)Ra and (40)K can be assigned to 'natural background radioactivity', whereas the second model, followed by (210)Pb and (137)Cs, is based on 'atmospheric fallout radioactivity'. The main conclusion of this work is that CFPP has not influence on the radioactivity levels measured in the studied area, with has a mean annual outdoor effective dose E = 71 ± 22 μSv, very close to the average UNSCEAR value of 70 μSv, thus confirming the almost non-existent radioactive risk posed by the presence of the CFPP. PMID:23680923

  19. Quantification and Radiological Risk Estimation Due to the Presence of Natural Radionuclides in Maiganga Coal, Nigeria

    PubMed Central

    Kolo, Matthew Tikpangi; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd; Abdullah, Wan Hasiah Binti

    2016-01-01

    Following the increasing demand of coal for power generation, activity concentrations of primordial radionuclides were determined in Nigerian coal using the gamma spectrometric technique with the aim of evaluating the radiological implications of coal utilization and exploitation in the country. Mean activity concentrations of 226Ra, 232Th, and 40K were 8.18±0.3, 6.97±0.3, and 27.38±0.8 Bq kg-1, respectively. These values were compared with those of similar studies reported in literature. The mean estimated radium equivalent activity was 20.26 Bq kg-1 with corresponding average external hazard index of 0.05. Internal hazard index and representative gamma index recorded mean values of 0.08 and 0.14, respectively. These values were lower than their respective precautionary limits set by UNSCEAR. Average excess lifetime cancer risk was calculated to be 0.04×10−3, which was insignificant compared with 0.05 prescribed by ICRP for low level radiation. Pearson correlation matrix showed significant positive relationship between 226Ra and 232Th, and with other estimated hazard parameters. Cumulative mean occupational dose received by coal workers via the three exposure routes was 7.69 ×10−3 mSv y-1, with inhalation pathway accounting for about 98%. All radiological hazard indices evaluated showed values within limits of safety. There is, therefore, no likelihood of any immediate radiological health hazards to coal workers, final users, and the environment from the exploitation and utilization of Maiganga coal. PMID:27348624

  20. Quantification and Radiological Risk Estimation Due to the Presence of Natural Radionuclides in Maiganga Coal, Nigeria.

    PubMed

    Kolo, Matthew Tikpangi; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd; Abdullah, Wan Hasiah Binti

    2016-01-01

    Following the increasing demand of coal for power generation, activity concentrations of primordial radionuclides were determined in Nigerian coal using the gamma spectrometric technique with the aim of evaluating the radiological implications of coal utilization and exploitation in the country. Mean activity concentrations of 226Ra, 232Th, and 40K were 8.18±0.3, 6.97±0.3, and 27.38±0.8 Bq kg-1, respectively. These values were compared with those of similar studies reported in literature. The mean estimated radium equivalent activity was 20.26 Bq kg-1 with corresponding average external hazard index of 0.05. Internal hazard index and representative gamma index recorded mean values of 0.08 and 0.14, respectively. These values were lower than their respective precautionary limits set by UNSCEAR. Average excess lifetime cancer risk was calculated to be 0.04×10-3, which was insignificant compared with 0.05 prescribed by ICRP for low level radiation. Pearson correlation matrix showed significant positive relationship between 226Ra and 232Th, and with other estimated hazard parameters. Cumulative mean occupational dose received by coal workers via the three exposure routes was 7.69 ×10-3 mSv y-1, with inhalation pathway accounting for about 98%. All radiological hazard indices evaluated showed values within limits of safety. There is, therefore, no likelihood of any immediate radiological health hazards to coal workers, final users, and the environment from the exploitation and utilization of Maiganga coal. PMID:27348624

  1. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Méndez-García, C.; Renteria-Villalobos, M.; García-Tenorio, R.; Montero-Cabrera, M. E.

    2014-07-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. 232Th-series, 238U-series, 40K and 137Cs activity concentrations (AC, Bq kg-1) were determined by gamma spectrometry with a high purity Ge detector. 238U and 234U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to 210Pb activities. Results were verified by 137Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High 238U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento - Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) 234U/overflow="scroll">238U and 238U/overflow="scroll">226Ra in sediments have values between 0.9-1.2, showing a behavior close to radioactive equilibrium in the entire basin. 232Th/overflow="scroll">238U, 228Ra/overflow="scroll">226Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  2. Evaluation of radiological risks due to natural radioactivity around Lynas Advanced Material Plant environment, Kuantan, Pahang, Malaysia.

    PubMed

    Kolo, Matthew Tikpangi; Aziz, Siti Aishah Binti Abdul; Khandaker, Mayeen Uddin; Asaduzzaman, Khandoker; Amin, Yusoff Mohd

    2015-09-01

    Understanding the public awareness concerning the Lynas Advanced Material Plant (LAMP), an Australian rare earths processing plant located in Malaysia, a radiological study in soil and water samples collected at random surrounding the LAMP environment was undertaken using HPGe gamma-ray spectrometry. The mean soil activities for (226)Ra, (232)Th, and (40)K were found to be 6.56 ± 0.20, 10.62 ± 0.42, and 41.02 ± 0.67 Bq/kg, respectively, while for water samples were 0.33 ± 0.05, 0.18 ± 0.04, and 4.72 ± 0.29 Bq/l, respectively. The studied areas show typical local level of radioactivity from natural background radiation. The mean gamma absorbed dose rate in soils at 1 m above the ground was found to be 11.16 nGy/h. Assuming a 20 % outdoor occupancy factor, the corresponding annual effective dose showed a mean value of 0.014 mSv year(-1), significantly lower than the worldwide average value of 0.07 mSv year(-1) for the annual outdoor effective dose as reported by UNSCEAR (2000). Some other representative radiation indices such as activity utilization index (AUI), H ex, H in, excess lifetime cancer risk (ELCR), and annual gonadal dose equivalent (AGDE) were derived and also compared with the world average values. Statistical analysis performed on the obtained data showed a strong positive correlation between the radiological variables and (226)Ra and (232)Th. PMID:25925148

  3. Measurement of natural radioactivity in bottled drinking water in Pakistan and consequent dose estimates.

    PubMed

    Fatima, I; Zaidi, J H; Arif, M; Tahir, S N A

    2007-01-01

    Natural radioactivity was determined in 11 different brands of commonly sold bottled drinking water in the federal capital Islamabad and Rawalpindi city of Pakistan using gamma spectrometry technique. Mean concentrations of 226Ra, 232Th and (40)K were found to be 11.3 +/- 2.3, 5.2 +/- 0.4 and 140.9 +/- 30.6 mBq l(-1), respectively. The annual cumulative effective doses due to all three natural radionuclides for different age groups of 1-5 y, 5-10 y, 10-15 y and adults (>or=18 y) were estimated to be 4.0, 3.4, 3.1 and 4.1 microSv y(-1), respectively. Among the three natural radionuclides, annual effective doses for all age groups from 226Ra were significant. Children in the age group of 1-5 y appeared to be at risk with respect to the annual effective doses from 226Ra as compared to the other age groups. Results obtained in this study are compared with the reported values from other countries of the world and it was observed that measured activity concentrations of three natural radionuclides in the bottled drinking water were lower than these values. Annual estimated effective doses for all four age groups from the intake of natural radionuclides in bottled drinking water were also found below the World Health Organisation (WHO) recommended limit of 0.1 mSv y(-1) as well as the average radiation dose of 0.29 mSv y(-1) received per head worldwide due to ingestion of natural radionuclides assessed by UNSCEAR (2000). PMID:16877468

  4. Natural radioactivity contents in tobacco and radiation dose induced from smoking.

    PubMed

    Shousha, Hany A; Ahmad, Fawzia

    2012-06-01

    One of the causative factors for cancer-inducing mechanisms in humans is radioactive elements present in tobacco leaves used in the manufacture of cigarettes. Smoking of tobacco and its products increases the internal intake and radiation dose due to naturally occurring radionuclides that are considered to be one of the most significant causes of lung cancer. In this work, different commercial types of cigarettes, cigar and moassel were collected from market. Naturally occurring radionuclides (226)Ra and (214)Bi ((238)U series), (228)Ac and (228)Ra ((232)Th series), (40)K  and man-made (137)Cs were measured in tobacco using gamma-ray spectrometer. Results show that the average concentrations of (238)U, (232)Th and (40)K were 4.564, 3.940 and 1289.53 Bq kg(-1), respectively. This reflects their origin from the soil by root uptake and fertilisers used in the cultivation of tobacco plants. Concentration of (137)Cs was 0.348 Bq kg(-1) due to root uptake or deposition onto the leaf foliage. For smokers, the annual effective dose due to inhalation of (238)U varied from 49.35 to 139.40 μSv(-1) (average 104.27 μSv y(-1)), while of (232)Th from 23.86 to 111.06 μSv y(-1) (average 65.52 μSv y(-1)). The annual effective dose resulting from (137)Cs was varied from 10.96 to 24.01 nSv y(-1) (average 19.41 nSv y(-1)). PMID:21926418

  5. Triply degenerate quantum mixture of 41K, 40K and 6Li

    NASA Astrophysics Data System (ADS)

    Wu, Cheng-Hsun; Santiago, Ibon; Park, Jee Woo; Ahmadi, Peyman; Zwierlein, Martin

    2011-05-01

    We report the observation of a triply quantum degenerate mixture of 41K, 40K and 6Li atoms. It is demonstrated that bosonic 41K atom is an efficient coolant for sympathetic cooling of fermionic 40K and 6Li atoms. We also present our investigation of 41K and 40K, a Bose-Fermi mixture where a 12 G s-wave resonance is observed. Negligible differential gravitational sag between potassium isotopes makes this resonance an excellent candidate for studying unexplored properties of Bose- Fermi mixtures. The 40K and 6Li mixture provides access to strongly correlated Fermi-Fermi mixtures with imbalanced masses. This work was supported by the NSF, AFOSR-MURI, AFOSR-YIP, ARO-MURI, a grant from the Army Research Office with funding from the DARPA OLE program, the David and Lucille Packard Foundation and the Alfred P. Sloan Foundation.

  6. Accumulation and translocation peculiarities of (137)Cs and (40)K in the soil--plant system.

    PubMed

    Marčiulionienė, Danutė; Lukšienė, Benedikta; Jefanova, Olga

    2015-12-01

    Long-term investigations (1996-2008) were conducted into the (137)Cs and (40)K in the soil of forests, swamps and meadows in different regions of Lithuania, as well as in the plants growing in these media. The (137)Cs and (40)K activity concentrations, the (137)Cs/(40)K activity concentration ratio and accumulation, and translocation in the system, i.e. from the soil to plant roots to above-ground plant part of these radionuclides, were evaluated after gamma-spectrometric measurements using a high purity germanium (HPGe) detector. Based on the obtained data, it can be asserted that in the tested plant species, the (137)Cs and (40)K accumulation, the transfer from soil to roots and translocation within the plants depend on the plant species and environmental ecological conditions. The (137)Cs/(40)K activity concentration ratios in the same plant species in different regions of Lithuania are different and this ratio depends on the biotope (forest, swamp or meadow) in which the plant grows and on the location of the growing region. Based on the determined trends of statistically reliable inverse dependence between the activity concentrations in both soil and plants, it can be stated that the exchange of (137)Cs and (40)K in plants and soil is different. Different accumulations and translocations of investigated radionuclides in the same plant species indicate diverse biological metabolism of (137)Cs and its chemical analogue (40)K in plants. A competitive relationship exists between (137)Cs and (40)K in plants as well as in the soil. PMID:26301832

  7. Natural radioactivity distribution and gamma radiation exposure of beach sands from Sithonia Peninsula

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Argyrios; Christofides, Georgios; Koroneos, Antonios; Stoulos, Stylianos

    2014-06-01

    This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along the beaches of Sithonia Peninsula which are adjacent to the rock-types of the Sithonia Plutonic Complex. These range from 6-673, 5-767, 5-1750, 6-1760 and 185-875 Bq/kg respectively. The (% wt.) heavy magnetic (HM) fraction (epidote, allanite, hornblende, biotite and garnet), the heavy non-magnetic (HNM) fraction (monazite, zircon, titanite and apatite) and the total heavy (TH) fraction, were correlated with the concentrations of the measured radionuclides in the bulk samples. The HNM fraction seems to control the activity concentrations of 238U in all samples, while the HM fraction, at least for the heavy mineral rich samples bearing high amounts of epidote crystals with allanite cores, controls their 232Th content. The measured radionuclides in beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parent rocks, in order to provide data on their enrichment or depletion. The annual effective dose varies from 0.013 to 0.688 mSv y-1 for local people working on the beach, while for tourists the annual external effective dose ranges between 0.003 and 0.165 mSv y-1.

  8. High-precision calculation of the branching ratio of the 40K decay constant.

    NASA Astrophysics Data System (ADS)

    Jourdan, F.

    2008-12-01

    40K is of great importance in Earth science, particularly for K/Ar, 40Ar/39Ar and K/Ca geochronology. The decay scheme of the 40K includes two different modes of decay, beta and electron capture followed by gamma-ray emission, which yield two different products, 40Ca* and 40Ar*. The relative probability that 40K decay following one of the two schemes is known as the branching ratio. An original method of calculation to obtain the value of the 40K branching ratio (λβ- /λtot) based on the K/Ar technique, is proposed. λβ- /λtot is obtained by combining the 40Ar*/40K value of Fish Canyon sanidine (FCs) secondary standard derived from four primary 40Ar/39Ar standards, with the current best estimates of the age of FCs and the value of the 40K total decay constant. The latest estimation of the 40K total decay constant and the age of FCs by Mundil et al. (2006), through comparison with U/Pb ages, yields a λβ- /λtot value of 89.59 ± 0.03% (1σ; relative error = ± 0.035%). Indirect measurement of the age of FCs by orbital tuning (Kuiper et al., 2008) combined with the value of 40K total decay constant measured by liquid scintillation counting by Kossert and Gunther (2004) yields a statistically indistinguishable value for the branching ratio of 89.61 ± 0.03%, with an average between the two values of 89.60 ± 0.04%. The method proposed here allows can easily be applied to further constrain the value of the 40K branching ratio as future refinements of the 40K decay constant and FCs age are produced, although it is expected that the adopted value will be close to λβ- /λtot = 89.60 ± 0.04%. Kossert and Gunther, 2004. Appl. Radiat. Isot. 60, 459-464. Kuiper et al., 2008. Science 320, 500-504. Mundil et al. 2006, Eos Trans. AGU, 87(52)

  9. Joint determination of 40K decay constants and 40Ar∗/ 40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/ 39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Renne, Paul R.; Mundil, Roland; Balco, Greg; Min, Kyoungwon; Ludwig, Kenneth R.

    2010-09-01

    40Ar/ 39Ar and K-Ar geochronology have long suffered from large systematic errors arising from imprecise K and Ar isotopic data for standards and imprecisely determined decay constants for the branched decay of 40K by electron capture and β - emission. This study presents a statistical optimization approach allowing constraints from 40K activity data, K-Ar isotopic data, and pairs of 238U- 206Pb and 40Ar/ 39Ar data for rigorously selected rocks to be used as inputs for estimating the partial decay constants ( λ ɛ and λ β) of 40K and the 40Ar∗/ 40K ratio ( κFCs) of the widely used Fish Canyon sanidine (FCs) standard. This yields values of κFCs = (1.6418 ± 0.0045) × 10 -3, λ ɛ = (0.5755 ± 0.0016) × 10 -10 a -1 and λ β = (4.9737 ± 0.0093) × 10 -10 a -1. These results improve uncertainties in the decay constants by a factor of >4 relative to values derived from activity data alone. Uncertainties in these variables determined by our approach are moderately to highly correlated (cov( κFCs, λ ɛ) = 7.1889 × 10 -19, cov( κFCs, λ β) = -7.1390 × 10 -19, cov( λ ɛ, λ β) = -3.4497 × 10 -26) and one must take account of the covariances in error propagation by either linear or Monte Carlo methods. 40Ar/ 39Ar age errors estimated from these results are significantly reduced relative to previous calibrations. Also, age errors are smaller for a comparable level of isotopic measurement precision than those produced by the 238U/ 206Pb system, because the 40Ar/ 39Ar system is now jointly calibrated by both the 40K and 238U decay constants, and because λ ɛ( 40K) < λ( 238U). Based on this new calibration, the age of the widely used Fish Canyon sanidine standard is 28.305 ± 0.036 Ma. The increased accuracy of 40Ar/ 39Ar ages is now adequate to provide meaningful validation of high-precision U/Pb or astronomical tuning ages in cases where closed system behavior of K and Ar can be established.

  10. Body Potassium Content and Radiation Dose from 40K for the Urals Population (Russia)

    PubMed Central

    Tolstykh, Evgenia I.; Degteva, Marina O.; Bougrov, Nikolay G.; Napier, Bruce A.

    2016-01-01

    Long-term whole-body monitoring of radionuclides in residents of the Urals Region has been performed at the Urals Research Center for Radiation Medicine (URCRM, Chelyabinsk). Quantification of 40K was achieved by measuring the 40K photopeak with four phoswich detectors in whole body counter SICH-9.1M. The current study presents the results of 40K measurements in 3,651 women and 1,961 t-test; U-test men aged 11–90; measurements were performed in 2006–2014. The residents belonged to two ethnic groups, Turkic (Tatar, Bashkir) and Slavs (mainly Russian). The levels of 40K-body contents depend upon gender, age, and body mass. Significant ethnic-differences were not found in 40K-body contents and 40K concentrations in terms of Bq per kg of body weight (in groups homogenous by age and gender). Both 40K-body contents and concentrations were significantly higher in men than in women in all age-groups; the difference was about 25%. The measured 40K-body content in men of 20–50 years was about 4200 Bq (134 g of K) and about 3000 Bq (95 g of K) in women. By the age of 80 these values decreased to 3200 Bq (102 g of K) in men and 2500 Bq (80 g of K) in women. Annual dose rates were maximal in the age group of 20–30 years– 0.16 mGy/y for men and 0.13 mGy/y for women. Further, the dose-rates decreased with age and in the groups of 60–80 years were 0.13 mGy/y for men and 0.10 mGy/y for women. Within groups homogeneous by age and gender, individual dose rates are described by a normal statistical distribution. The coefficient of variation ranges from 9 to 14%, and on the average is 12.5%. Doses from naturally occurring 40K accumulated over 70 years were found to be 9.9 mGy for men and 8.3 mGy for women; over 90 years - 12.5 and 10.4 mGy. PMID:27111330

  11. Body Potassium Content and Radiation Dose from 40K for the Urals Population (Russia).

    PubMed

    Tolstykh, Evgenia I; Degteva, Marina O; Bougrov, Nikolay G; Napier, Bruce A

    2016-01-01

    Long-term whole-body monitoring of radionuclides in residents of the Urals Region has been performed at the Urals Research Center for Radiation Medicine (URCRM, Chelyabinsk). Quantification of 40K was achieved by measuring the 40K photopeak with four phoswich detectors in whole body counter SICH-9.1M. The current study presents the results of 40K measurements in 3,651 women and 1,961 t-test; U-test men aged 11-90; measurements were performed in 2006-2014. The residents belonged to two ethnic groups, Turkic (Tatar, Bashkir) and Slavs (mainly Russian). The levels of 40K-body contents depend upon gender, age, and body mass. Significant ethnic-differences were not found in 40K-body contents and 40K concentrations in terms of Bq per kg of body weight (in groups homogenous by age and gender). Both 40K-body contents and concentrations were significantly higher in men than in women in all age-groups; the difference was about 25%. The measured 40K-body content in men of 20-50 years was about 4200 Bq (134 g of K) and about 3000 Bq (95 g of K) in women. By the age of 80 these values decreased to 3200 Bq (102 g of K) in men and 2500 Bq (80 g of K) in women. Annual dose rates were maximal in the age group of 20-30 years- 0.16 mGy/y for men and 0.13 mGy/y for women. Further, the dose-rates decreased with age and in the groups of 60-80 years were 0.13 mGy/y for men and 0.10 mGy/y for women. Within groups homogeneous by age and gender, individual dose rates are described by a normal statistical distribution. The coefficient of variation ranges from 9 to 14%, and on the average is 12.5%. Doses from naturally occurring 40K accumulated over 70 years were found to be 9.9 mGy for men and 8.3 mGy for women; over 90 years - 12.5 and 10.4 mGy. PMID:27111330

  12. Kaman 40-kW wind system. Phase II. Fabrication and tests. Volume II. Technical report

    SciTech Connect

    Howes, H; Perley, R

    1981-01-01

    A program is underway to design, fabricate and test a horizontal axis Wind Turbine Generator (WTG) capable of producing 40 kW electrical output power in a 20 mph wind. Results are presented of the program effort covering fabrication and testing of the Wing Turbine Generator designed earlier. A minimum of difficulties were experienced during fabrication and, after successful completion of Contractor tests through 20 mph winds, the WTG was shipped to Rocky Flats, assembled and operated there. The 40 kW WTG is presently undergoing extended tests at Rockwell's Rocky Flats test facility.

  13. Assessment of gamma radiation exposure and distribution of natural radioactivity in beach sands associated with plutonic rocks of Greece

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Argyrios; Koroneos, Antonios; Christofides, Georgios; Stoulos, Stylianos

    2016-04-01

    This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along beaches of Greece associated with plutonic rocks. They range from 6-940, 1-2292, 5-10143, 5-9953 and 27-1319 Bq/kg respectively, with some of them representing the highest values of natural radioactivity measured in sediments in Greece. The investigated beaches include Sithonia peninsula (Chalkidiki, N. Greece), some islands of the Aegean Sea (Mykonos, Paros, Naxos, Serifos, Ikaria), the area of Kavala (N. Greece), Samothraki island, NE Chalkidiki and Maronia (NE Greece). Several of these places are associated with high touristic activity such as Mykonos, Naxos, Paros, Serifos, Ikaria, Sithonia and Kavala. The (% wt.) heavy magnetic fraction (HM) (allanite, amphibole, mica, clinopyroxene, magnetite and hematite), the heavy non-magnetic fraction (HNM) (monazite, zircon, titanite and apatite) and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The heavy fractions seem to control the activity concentrations of 238U and 232Th of all the samples, showing some local differences in the main 238U and 232Th mineral carrier. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The highest values of the equivalent dose have been reported in Mykonos, Naxos, Kavala and Sithonia. The annual equivalent dose which should be limited to at least 1 mSv y-1, varies between 0.003 and 0.759 mSv y-1 for tourists and from 0.012 to 3.164 mSv y-1 for local people working on the beach.

  14. Anthropogenic and geogenic radionuclides content in an undisturbed Slovenian forest soil

    NASA Astrophysics Data System (ADS)

    P, Jankong; L, Mabit; A, Toloza; v, Zupanc

    2010-05-01

    The measurements of natural background radiation and anthropogenic radionuclides in terrestrial environment, especially in soil, have been carried out in many countries for several decades to establish base line data of radiation level. So far, the knowledge of radionuclides concentration levels in Slovenia is limited to a few investigations and the use of anthropogenic 137Cs radionuclide has not yet been used as soil landscape tracer in Slovenia. Therefore, the purposes of this study were: (i) to collect the inventory information of naturally occurring isotope (40K, 226Ra, 232Th, 235U and 238U) and man-made radionuclides (137Cs) as well as their depth/vertical distribution in soil; (ii) to complete radio-ecological survey information in Slovenia and provide information regarding the external dose-rate based on the depth distributions of the gamma emitters in the soil of the study area; and (iii) to establish a reference inventory value of 137Cs fallout in order to prepare for a future investigation to test 137Cs as soil tracer under Slovenian agro-environment. To estimate the natural level of radioactivity and the initial fallout of 137Cs, twenty soil profiles (0-40cm) divided into four increments of 10 cm were collected in an undisturbed forest located in East Slovenia in Šalamenci close to the Hungarian and Austrian borders at the beginning of the Pannonian plains. Depending on the depth increment, the average activity concentration of 137Cs, 40K, 226Ra, 232Th, 235U and 238U were found to be respectively from 0.47 ± 0.27 to 70 ± 33 Bq kg-1, from 535 ± 16 to 703 ± 20 Bq kg-1, from 51 ± 3 to 49 ± 2 Bq kg-1, from 54 ± 6 to 62 ± 4 Bq kg-1, from 7.8 ± 0.8 to 8.1 ± 0.3 Bq kg-1and from 58 ± 22 to 68 ± 27 Bq kg-1. On average the top soil mass activity of 40K is 7 to 8 times higher than that of 137Cs and the depth distribution of this isotope, instead of showing a constant amount along the soil profile, presents an increase with depth. The external gamma

  15. Radiological Impact of Phosphogypsum Application in Agriculture

    SciTech Connect

    Dias, Nivea M. P.; Caires, Eduardo F.; Pires, Luiz F.; Bacchi, Marcio A.; Fernandes, Elisabete A. N.

    2010-08-04

    Phosphogypsum (PG) contains radionuclides from {sup 238}U and {sup 232}Th decay series. Due to the presence of these radionuclides, many countries restricted the use of PG in agriculture, however there is not such restriction in Brazil. The main objective of this work was to evaluate the impact of PG application on {sup 226}Ra ({sup 238}U) and {sup 228}Ra ({sup 232}Th) concentrations in soil. Gamma-spectrometry was carried out using HPGe detector. No increment of {sup 226}Ra and {sup 228}Ra was observed for increasing PG doses. Average values found for {sup 226}Ra and {sup 228}Ra were respectively 37 Bq kg{sup -1} and 57 Bq kg{sup -1}. The results showed that the increasing PG doses in the specific conditions of the experiment did not cause a significant increment of radionuclides.

  16. Electric manipulation of ultracold polar ^40K^87Rb molecules in a magnetic field

    NASA Astrophysics Data System (ADS)

    Quéméner, Goulven; Bohn, John

    2009-05-01

    Ultracold fermionic polar molecules of ^40K^87Rb in their absolute rovibronic ground state (v=0,n=0,^1σ) have been created recently [1] in a magnetic trap and open new perspectives to create fermionic degenerate gases of polar molecules. To achieve this goal, it is very important to understand the collisional properties of such molecules under magnetic and electric fields. In our presentation, we investigate ground state fermionic ^40K^87Rb + ^40K^87Rb collisions in the presence of a magnetic field and explore the possibility to control these collisions when an electric field is applied. We will explore the main physical processes that can lead to such manipulation. This problem is complicated by the Zeeman and Stark splitting of all levels of the polar molecules and by the possibility of forming ^40K2 + ^87Rb2 chemical products. 1 - K.-K. Ni, S. Ospelkaus, M. H. G. de Miranda, A. Pe'er, B. Neyenhuis, J. J. Zirbel, S. Kotochigova, P. S. Julienne, D. S. Jin, and J. Ye, Science 322, 231 (2008).

  17. Evidence for superconductivity above 40 K in the La-Ba-Cu-O compound system

    NASA Technical Reports Server (NTRS)

    Chu, C. W.; Hor, P. H.; Meng, R. L.; Gao, L.; Huang, Z. J.

    1987-01-01

    An apparent superconducting transition with an onset temperature above 40 K has been detected under pressure in the La-Ba-Cu-O compound system synthesized directly from a solid-state reaction of La2O3, CuO, and BaCO3 followed by a decomposition of the mixture in a reduced atmosphere. The experiment is described and the results of effects of magnetic field and pressure are discussed.

  18. Operation result of 40kW class MCFC pilot plant

    SciTech Connect

    Saitoh, H.; Hatori, S.; Hosaka, M.; Uematsu, H.

    1996-12-31

    Ishikawajima-Harima Heavy Industries Co., Ltd. developed unique Molten Carbonate Fuel Cell (MCFC) system based on our original concept. To demonstrate the possibility of this system, based on MCFC technology of consigned research from New Energy and Industrial Technology Development Organization (NEDO) in Japan, we designed 40kW class MCFC pilot plant which had all equipments required as a power plant and constructed in our TO-2 Technical Center. This paper presents the test results of the plant.

  19. McDonnell 40-kW Giromill Wind System. Phase II. Fabrication and test

    SciTech Connect

    Brulle, R

    1980-06-01

    A 40 kW vertical axis windmill called a ''Giromill'' was fabricated, erected, and tested. The system design is described as well as some design changes made during fabrication. Manufacturing cost estimates are updated. Fabrication of the turbine blades, support arms, and fixed and rotating tower is described as well as the tests. Testing included control systems acceptance tests; Giromill system acceptance tests; structural, mechanical, control system and electric generation operational tests; and performance tests connected to the utility grid. (LEW)

  20. Measurement of natural radioactive nuclide concentrations in various metal ores used as industrial raw materials in Japan and estimation of dose received by workers handling them.

    PubMed

    Iwaoka, Kazuki; Tagami, Keiko; Yonehara, Hidenori

    2009-11-01

    Natural resources such as ores and rocks contain natural radioactive nuclides at various concentrations. If these resources contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore, it is important to investigate the radioactive activity in these resources. In this study, concentrations of radioactive nuclides in Th, Zr, Ti, Mo, Mn, Al, W, Zn, V, and Cr ores used as industrial raw materials in Japan were investigated. The concentrations of (238)U and (232)Th were determined by inductively coupled plasma mass spectrometry (ICP-MS), while those of (226)Ra, (228)Ra, and (40)K were determined by gamma-ray spectrum. We found the concentrations of (238)U series, (232)Th series, and (40)K in Ti, Mo, Mn, Al, W, Zn, V, and Cr ores to be lower than the critical values defined by regulatory requirements as described in the International Atomic Energy Agency (IAEA) Safety Guide. The doses received by workers handling these materials were estimated by using methods for dose assessment given in a report by the European Commission. In transport, indoor storage, and outdoor storage scenarios, an effective dose due to the use of Th ore was above 4.3 x 10(-2)Sv y(-1), which was higher than that of the other ores. The maximum value of effective doses for other ores was estimated to be about 4.5 x 10(-4)Sv y(-1), which was lower than intervention exemption levels (1.0 x 10(-3)Sv y(-1)) given in International Commission of Radiological Protection (ICRP) Publication 82. PMID:19703725

  1. Radiation Doses to Members of the U.S. Population from Ubiquitous Radionuclides in the Body: Part 1, Autopsy and In Vivo Data

    SciTech Connect

    Watson, David J.; Strom, Daniel J.

    2011-02-25

    This paper is part one of a three-part series investigating annual effective doses to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. This series of papers explicitly excludes intakes from inhaling 222Rn, 220Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. The goal of part one of this work was to review, summarize, and characterize all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Forty-five papers and reports were obtained and their data reviewed, and three data sets were obtained via private communication. The 45 radionuclides of interest are the 238U series (14 nuclides), the actinium series (headed by 235U; 11 nuclides), and the 232Th series (11 nuclides); primordial radionuclides 87Rb and 40 K; cosmogenic and fallout radionuclides 14C and 3H; and purely anthropogenic radionuclides 137Cs-137mBa, 129I, and 90Sr-90Y. Measurements judged to be relevant were available for only 15 of these radionuclides: 238U, 235U, 234U, 232Th, 230Th, 228Th, 228Ra, 226Ra, 210Pb, 210Po, 137Cs, 87Rb, 40K, 14C, and 3H. Recent and relevant measurements were not available for 129I and 90Sr-90Y. A total of 11,714 radionuclide concentration measurements were found in one or more tissues or organs from 14 States. Data on age, sex, geographic locations, height, and weight of subjects were available only sporadically. Too often authors did not provide meaningful values of uncertainty of measurements so that variability in data sets is confounded with measurement uncertainty. The following papers detail how these shortcomings are overcome to achieve the goals of the three-part series.

  2. Assessment of natural and anthropogenic radioactivity levels in rocks and soils in the environs of Swieradow Zdroj in Sudetes, Poland, by in situ gamma-ray spectrometry.

    PubMed

    Malczewski, D; Teper, L; Dorda, J

    2004-01-01

    The natural radioactivity of 40K, 208Ti, 212Pb, 214Pb, 228Ac, and the fallout of 137Cs in typical rocks and soils of Swieradów Zdrój area (Sudetes Mountains, Poland) were measured in situ using a portable gamma-ray spectrometry workstation. The measurement points were chosen for different regional lithology: within hornfelses of the Szklarska Poreba schist-belt, quartz rocks, gneisses of the Swieradów Zdrój unit, leucogranites, leptinites, mica schists of the Stara Kamienica belt, and finally the zones of the southern and northern contacts of the Stara Kamienica schist-belt with leucogranites and gneisses of the Lesna unit, respectively. 40K activity varied in the range from about 320 Bq kg(-1) (quartz) to 1200 Bq kg(-1) (gneisses). The activity concentrations associated with 228Ac (232Th series) varied in the range from 25 Bq kg(-1) (quartz) to 62 Bq kg(-1) (leucogranites), whereas activity concentration of 226Ra varied in the range from about 31 Bq kg(-1) (hornfelses) to 122 Bq kg(-1) (leucogranites). Relatively low deposits of 137Cs were noted in the investigated area, where the activity concentrations ranged from 4001 (hornfelses) Bq m(-2) to less than 154 Bq m(-2) (leucogranites). PMID:15050357

  3. Radiological study of exposure levels in El Maghara underground coal mine.

    PubMed

    Amer, Hany A; Shawky, S; Hussein, Mohamed I; Abd el-Hady, M L

    2002-08-01

    Coal is largely composed of organic matter, but it is the inorganic matter in coal minerals and trace elements that have been cited as possible causes of health, environmental and technological problems associated with the use of coal. Some trace elements in coal are naturally radioactive. These radioactive elements include uranium (U), thorium (Th) and their numerous decay products, including radium (Ra) and radon (Rn). Although these elements are less chemically toxic than other coal constituents, such as arsenic, selenium or mercury, questions have been raised concerning the possible risk from radiation. In order to accurately address these questions and to predict the mobility of radioactive elements during the coal fuel cycle, it is important to determine the specific activity, distribution and form of radioactive elements in coal. The assessment of the radiation exposure from coal burning is critically dependent on the specific activity of radioactive elements in coal and in the fly ash that remains after combustion. The El-Maghara coal mine is the only producing coal mine in Egypt. It is located in the middle of the Sinai desert about 250 km north-east of Cairo, where a coal-fired power plant is intended to be built. In this study, a pre-operational radiological baseline of the site and the occupational radiation exposures due to radon progeny in the mine were determined. The specific activities of 226Ra, 232Th and 40K in soil and coal dust samples collected along the main gallery ranges were found to be 6-22.9, 9.6-47.3 and 77-489 Bq kg-1, respectively. Soil samples collected around the mine showed concentrations of 226Ra, 232Th and 40K in the ranges 2.7-20.2, 3.2-12.6 and 14.6-201 Bq kg-1, respectively. All of the mean values of radon progeny were lower than the action levels for working places recommended in the International Commission on Radiological Protection (ICRP) 65. PMID:12196005

  4. Assessment of radiological hazards of naturally occurring radioactive materials in cement industry.

    PubMed

    Aslam, Muhammad; Gul, Rahmat; Ara, Tauseef; Hussain, Manzur

    2012-09-01

    A study on the radiological hazard in Portland cement due to the presence of naturally occurring radioactive materials is being carried out. The Portland cement manufactured in the Islamabad/Rawalpindi region of Pakistan, intermediate products (clinker) and the various raw materials which compose the product have been analysed for (226)Ra, (232)Th and (40)K using a gamma spectrometry system with a N-type high-purity germanium detector of 80 % relative efficiency. From the measured gamma ray spectra, specific activities were determined. The mean values of the total specific activity of (226)Ra, (232)Th and (40)K are 34.2±11.9, 29.1±3.6 and 295.1±66.9 Bq kg(-1), respectively in Portland cement, 28.4±8.7, 11.3±1.7 and 63.1±17.3 Bq kg(-1), respectively in lime stone, 8.2±1.9, 16.2±3.9 and 187.7±53.2 Bq kg(-1), respectively in gypsum, 34.7±13.1, 41.2±6.7 and 187.6±17.2 Bq kg(-1), respectively in clay, 41.1±11.8, 39.3±6.9 and 195.1±29.2 Bq kg(-1), respectively in latrite and 51.1±18.2, 23.2±1.2 and 258.4±15.3 Bq kg(-1), respectively in clinker. The radium equivalent activities (Ra(eq)), external hazard index (H(ex)), internal hazard index (H(in)), absorbed dose rate in air (D) and annual effective dose rate (E(eff)) were also determined. The measured activity concentrations for these radio nuclides and radiological indices were compared with the reported national and international data. All these measured values are comparable with the worldwide data reported in UNSCEAR publications. PMID:22355168

  5. Natural radioactivity in surface soil samples from dwelling areas in Tehran city, Iran.

    PubMed

    Asgharizadeh, F; Ghannadi, M; Samani, A B; Meftahi, M; Shalibayk, M; Sahafipour, S A; Gooya, E S

    2013-09-01

    The study was carried out to determine radioactivity concentrations in surface soil samples of the city of Tehran and associated potential radiological hazards. The natural radionuclide ((226)Ra, (232)Th and (40)K) contents were determined for 50 locations throughout the geological surface formations in a representative area in the city of Tehran, Iran, using high-resolution gamma-spectrometric analysis. The range of activity concentrations of (226)Ra, (232)Th and (40)K in the soil from the studied areas varies from 30.5±0.6 to 45.4±0.9, 27.3±0.5 to 57.1±1.1 and 328.0±4.6 to 768.5±13.4 Bq kg(-1) with overall mean values of 38.8±0.7, 43.4±0.8 and 555.1±8.9 Bq kg(-1), respectively. The mean radium equivalent activity, external hazard index, internal hazard index to quantify the internal exposure to radon and its daughter products, as well as the gamma activity concentration index for each sample are 143.6±4.6 Bq kg(-1), 0.39, 0.49 and 0.53, respectively. The average estimated radium equivalent is comparable with reported values for many countries in the world. Therefore, these areas may not pose radiological risks to the inhabitants due to harmful effects of the ionising radiation from the natural radioactivity in soil. The calculated average external and internal hazard indexes were found to be less than unity, as a recommended safe level. Estimates of the measured radionuclide content have been made for calculating the absorbed dose rate in the outdoor air at 1 m above the ground level. The absorbed dose rates resulting from those concentrations ranged from 48.1 to 88.7 nGy h(-1). Assuming a 20 % occupancy factor proposed by UNSCEAR, 2000, the corresponding effective dose rates in outdoor air equivalent to the population were calculated to be between 0.06 and 0.11 mSv y(-1). The measurement results and calculated values obtained from this study indicate that the dwelling areas in Tehran city, Iran, have background radioactivity levels within natural

  6. Distribution and environmental impacts of heavy metals and radioactivity in sediment and seawater samples of the Marmara Sea.

    PubMed

    Otansev, Pelin; Taşkın, Halim; Başsarı, Asiye; Varinlioğlu, Ahmet

    2016-07-01

    In this study, the natural and anthropogenic radioactivity levels in the sediment samples collected from the Marmara Sea in Turkey were determined. The average activity concentrations (range) of (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were found to be 23.8 (13.8-34.2) Bq kg(-1), 18.8 (6.4-25.9) Bq kg(-1), 23.02 (6.3-31.1) Bq kg(-1), 558.6 (378.8-693.6) Bq kg(-1) and 9.14 (4.8-16.3) Bq kg(-1), respectively. Our results showed that the average activity concentrations of (226)Ra, (238)U and (232)Th in the sediment samples were within the acceptable limits; whereas the average activity concentration of (40)K in the sediment samples was higher than the worldwide average concentration. The average radium equivalent activity, the average absorbed dose rate and the average external hazard index were calculated as 100.01 Bq kg(-1), 48.32 nGy h(-1) and 0.27, respectively. The average gross alpha and beta activity in the seawater samples were found to be 0.042 Bq L(-1) and 13.402 Bq L(-1), respectively. The gross alpha and beta activity concentrations increased with water depth in the same stations. The average heavy metal concentrations (range) in the sediment samples were 114.6 (21.6-201.7) μg g(-1) for Cr, 568.2 (190.8-1625.1) μg g(-1) for Mn, 39.3 (4.9-83.4) μg g(-1) for Cu, 85.5 (11.0-171.8) μg g(-1) for Zn, 32.9 (9.1-73.1) μg g(-1) for Pb and 49.1 (6.8-103.0) μg g(-1) for Ni. S5 station was heavily polluted by Cr, Cu, Ni and Pb. The results showed that heavy metal enrichment in sediments of the Marmara Sea was widespread. PMID:27060635

  7. Measurements of radioactivity and dose assessments in some building materials in Bitlis, Turkey.

    PubMed

    Kayakökü, Halime; Karatepe, Şule; Doğru, Mahmut

    2016-09-01

    In this study, samples of perlite, pumice and Ahlat stones (Ignimbrite) extracted from mines in Bitlis and samples of other building materials produced in facilities in Bitlis were collected and analyzed. Activity concentrations of (226)Ra, (232)Th and (40)K in samples of building materials were measured using NaI detector (NaI(Tl)) with an efficiency of 24%. The radon measurements of building material samples were determined using CR-39 nuclear track detectors. (226)Ra, (232)Th and (40)K radioactivity concentrations ranged from (29.6±5.9 to 228.2±38.1Bq/kg), (10.8±5.4 to 95.5±26.1Bq/kg) and (249.3±124.7 to 2580.1±266.9Bq/kg), respectively. Radon concentration, radium equivalent activities, absorbed dose rate, excess lifetime cancer risk and the values of hazard indices were calculated for the measured samples to assess the radiation hazards arising from using those materials in the construction of dwellings. Radon concentration ranged between 89.2±12.0Bq/m(3) and 1141.0±225.0Bq/m(3). It was determined that Raeq values of samples conformed to world standards except for perlite and single samples of brick and Ahlat stone. Calculated values of absorbed dose rate ranged from 81.3±20.5 to 420.6±42.8nGy/h. ELCR values ranged from (1.8±0.3)×10(-3) to (9.0±1.0)×10(-3). All samples had ELCR values higher than the world average. The values of Hin and Hex varied from 0.35±0.11 to 1.78±0.18 and from 0.37±0.09 to 1.17±0.13, respectively. The results were compared with standard radioactivity values determined by international organizations and with similar studies. There would be a radiation risk for people living in buildings made of perlite, Ahlat-1 and Brick-3. PMID:27389882

  8. Measurement of natural radioactivity and assessment of radiation hazard indices in soil samples at Pengerang, Kota Tinggi, Johor

    NASA Astrophysics Data System (ADS)

    Hassan, Nur Nazihah; Khoo, Kok Siong

    2014-02-01

    Pengerang area consists of a mix of private plantation, individual residential lots and state land, which is leased for agriculture related activities. The analysis was conducted to determine the specific activity of the initial value and the radiation hazard indices in the surrounding area in Pengerang. This area will be developed into a major downstream for oil and gas. The aims of this preliminary study were 1) to determine the specific activities of 238U, 232Th, 226Ra and 40K of soil samples at six selected areas by Gamma-ray spectrometry and 2) to calculate the radiation hazard indices. The specific activities (Bq/kg) of the samples ranged from 7.08±5.01 to 36.29±25.72 Bq/kg, 5.62±3.98 to 34.53±24.07 Bq/kg, 4.75±3.42 to 24.76±17.66 Bq/kg and 10.58±7.51 to 101.25±72.00 Bq/kg for 238U, 232Th, 226Ra and 40K, respectively. These values were well within the range that reported by UNSCEAR. The study also examined the radiation hazard indices, the mean values obtained were 48.49±28.06 Bq/kg for Radium Equivalent Activity (Raeq), 0.34 Bq/kg for Representative Level Index (Iγ), 21.83 nGy/h for Absorbed dose rates (D), 0.27 mSv/y for Annual Effective Dose Rates (Deff), 0.13 and 0.18 for External Hazards Index (Hex) and Internal Hazard Index (Hin), respectively. These calculated hazard indices were used to estimate the potential radiological health risk in soil and the dose rates associated with it were well below their permissible limit. The overall findings show that no radiological threat to the health of the population in the study area.

  9. Measurement of natural radioactivity and assessment of radiation hazard indices in soil samples at Pengerang, Kota Tinggi, Johor

    SciTech Connect

    Hassan, Nur Nazihah; Khoo, Kok Siong

    2014-02-12

    Pengerang area consists of a mix of private plantation, individual residential lots and state land, which is leased for agriculture related activities. The analysis was conducted to determine the specific activity of the initial value and the radiation hazard indices in the surrounding area in Pengerang. This area will be developed into a major downstream for oil and gas. The aims of this preliminary study were 1) to determine the specific activities of {sup 238}U, {sup 232}Th, {sup 226}Ra and {sup 40}K of soil samples at six selected areas by Gamma-ray spectrometry and 2) to calculate the radiation hazard indices. The specific activities (Bq/kg) of the samples ranged from 7.08±5.01 to 36.29±25.72 Bq/kg, 5.62±3.98 to 34.53±24.07 Bq/kg, 4.75±3.42 to 24.76±17.66 Bq/kg and 10.58±7.51 to 101.25±72.00 Bq/kg for {sup 238}U, {sup 232}Th, {sup 226}Ra and {sup 40}K, respectively. These values were well within the range that reported by UNSCEAR. The study also examined the radiation hazard indices, the mean values obtained were 48.49±28.06 Bq/kg for Radium Equivalent Activity (Raeq), 0.34 Bq/kg for Representative Level Index (I{sub γ}), 21.83 nGy/h for Absorbed dose rates (D), 0.27 mSv/y for Annual Effective Dose Rates (Deff), 0.13 and 0.18 for External Hazards Index (H{sub ex}) and Internal Hazard Index (H{sub in}), respectively. These calculated hazard indices were used to estimate the potential radiological health risk in soil and the dose rates associated with it were well below their permissible limit. The overall findings show that no radiological threat to the health of the population in the study area.

  10. Radioactivity of natural and artificial building materials - a comparative study.

    PubMed

    Szabó, Zs; Völgyesi, P; Nagy, H É; Szabó, Cs; Kis, Z; Csorba, O

    2013-04-01

    Building materials and their additives contain radioactive isotopes, which can increase both external and internal radioactive exposures of humans. In this study Hungarian natural (adobe) and artificial (brick, concrete, coal slag, coal slag concrete and gas silicate) building materials were examined. We qualified 40 samples based on their radium equivalent, activity concentration, external hazard and internal hazard indices and the determined threshold values of these parameters. Absorbed dose rate and annual effective dose for inhabitants living in buildings made of these building materials were also evaluated. The calculations are based on (226)Ra, (232)Th and (40)K activity concentrations determined by gamma-ray spectrometry. Measured radionuclide concentrations and hence, calculated indices and doses of artificial building materials show a rather disparate distribution compared to adobes. The studied coal slag samples among the artificial building materials have elevated (226)Ra content. Natural, i.e. adobe and also brick samples contain higher amount of (40)K compared to other artificial building materials. Correlation coefficients among radionuclide concentrations are consistent with the values in the literature and connected to the natural geochemical behavior of U, Th and K elements. Seven samples (coal slag and coal slag concrete) exceed any of the threshold values of the calculated hazard indices, however only three of them are considered to be risky to use according to the fact that the building material was used in bulk amount or in restricted usage. It is shown, that using different indices can lead to different conclusions; hence we recommend considering more of the indices at the same time when building materials are studied. Additionally, adding two times their statistical uncertainties to their values before comparing to thresholds should be considered for providing a more conservative qualification. We have defined radon hazard portion to point

  11. Deconstructing honeybee vitellogenin: novel 40 kDa fragment assigned to its N terminus

    PubMed Central

    Havukainen, Heli; Halskau, Øyvind; Skjaerven, Lars; Smedal, Bente; Amdam, Gro V.

    2011-01-01

    Vitellogenin, an egg-yolk protein precursor common to oviparous animals, is found abundantly in honeybee workers – a caste of helpers that do not usually lay eggs. Instead, honeybee vitellogenin (180 kDa) participates in processes other than reproduction: it influences hormone signaling, food-related behavior, immunity, stress resistance and longevity. The molecular basis of these functions is largely unknown. Here, we establish and compare the molecular properties of vitellogenin from honeybee hemolymph (blood) and abdominal fat body, two compartments that are linked to vitellogenin functions. Our results reveal a novel 40 kDa vitellogenin fragment in abdominal fat body tissue, the main site for vitellogenin synthesis and storage. Using MALDI-TOF combined with MS/MS mass-spectroscopy, we assign the 40 kDa fragment to the N terminus of vitellogenin, whereas a previously observed 150 kDa fragment corresponded to the remainder of the protein. We show that both protein units are N glycosylated and phosphorylated. Focusing on the novel 40 kDa fragment, we present a homology model based on the structure of lamprey lipovitellin that includes a conserved β-barrel-like shape, with a lipophilic cavity in the interior and two insect-specific loops that have not been described before. Our data indicate that the honeybee fat body vitellogenin experiences cleavage unlike hemolymph vitellogenin, a pattern that can suggest a tissue-specific role. Our experiments advance the molecular understanding of vitellogenin, of which the multiple physiological and behavioral effects in honeybees are well established. PMID:21270306

  12. Variation of 40 kHz Signal Level in Relation to Sunrise, Sunset and Climatic Condition

    NASA Astrophysics Data System (ADS)

    Guha, A.; De, B. K.; Saha, A.; Das, T. K.

    2007-07-01

    The sunrise effect, sunset effect, the diurnal and seasonal variations are the characteristic feature of low frequency (LF) radio wave propagated over a large distance. The normal character has been found to be perturbed during rainy days. The amplitude of 40 kHz signal transmitted from Miyakoji station, Japan and received in North-East India is remarkably attenuated after the commencement of rain. On the basis of nature of attenuation the observed records have been classified into two different forms viz., F1 and F2. An analysis in this regard is represented in this paper.

  13. Observation of 2D Fermionic Mott Insulators of 40K with Single-Site Resolution

    NASA Astrophysics Data System (ADS)

    Cheuk, Lawrence W.; Nichols, Matthew A.; Lawrence, Katherine R.; Okan, Melih; Zhang, Hao; Zwierlein, Martin W.

    2016-06-01

    We report on the site-resolved observation of characteristic states of the two-dimensional repulsive Fermi-Hubbard model, using ultracold 40K atoms in an optical lattice. By varying the tunneling, interaction strength, and external confinement, we realize metallic, Mott-insulating, and band-insulating states. We directly measure the local moment, which quantifies the degree of on-site magnetization, as a function of temperature and chemical potential. Entropies per particle as low as 0.99 (6 )kB indicate that nearest-neighbor antiferromagnetic correlations should be detectable using spin-sensitive imaging.

  14. Metrological traceability for AC High-Voltage in Inmetro up to 40 kV

    NASA Astrophysics Data System (ADS)

    Vitorio, P. C. O.; de Lima, V. R.; Borges Filho, O.; de Souza, L. A. A.; Asencios, O. W. G.

    2016-07-01

    This paper refers to a project carried out in Inmetro aiming to provide internal metrological traceability for 60 Hz AC High-Voltage up to 40 kV. It presents details about the method used, its equations and obtained results. A capacitance and tanb bridge, with a built-in current comparator, was used in combination with two standard capacitors to calibrate a standard potential transformer (PT), both in ratio and phase angle. The results obtained by Inmetro showed good agreement with PTB ones, for the same PT. The maximum estimated uncertainty was 0,0049% for ratio error and 104 μrad for phase angle error.

  15. Response of soil microorganisms to radioactive oil waste: results from a leaching experiment

    NASA Astrophysics Data System (ADS)

    Galitskaya, P.; Biktasheva, L.; Saveliev, A.; Ratering, S.; Schnell, S.; Selivanovskaya, S.

    2015-06-01

    Oil wastes produced in large amounts in the processes of oil extraction, refining, and transportation are of great environmental concern because of their mutagenicity, toxicity, high fire hazardousness, and hydrophobicity. About 40% of these wastes contain radionuclides; however, the effects of oil products and radionuclides on soil microorganisms are frequently studied separately. The effects on various microbial parameters of raw waste containing 575 g of total petroleum hydrocarbons (TPH) kg-1 waste, 4.4 of 226Ra, 2.8 of 232Th, and 1.3 kBq kg-1 of 40K and its treated variant (1.6 g kg-1 of TPH, 7.9 of 226Ra, 3.9 of 232Th, and 183 kBq kg-1 of 40K) were examined in a leaching column experiment to separate the effects of hydrocarbons from those of radioactive elements. The raw waste sample (H) was collected from tanks during cleaning and maintenance, and a treated waste sample (R) was obtained from equipment for oil waste treatment. Thermal steam treatment is used in the production yard to reduce the oil content. The disposal of H waste samples on the soil surface led to an increase in the TPH content in soil: it became 3.5, 2.8, and 2.2 times higher in the upper (0-20 cm), middle (20-40 cm), and lower (40-60cm) layers, respectively. Activity concentrations of 226Ra and 232Th increased in soil sampled from both H- and R- columns in comparison to their concentrations in control soil. The activity concentrations of these two elements in samples taken from the upper and middle layers were much higher for the R-column compared to the H-column, despite the fact that the amount of waste added to the columns was equalized with respect to the activity concentrations of radionuclides. The H waste containing both TPH and radionuclides affected the functioning of the soil microbial community, and the effect was more pronounced in the upper layer of the column. Metabolic quotient and cellulase activity were the most sensitive microbial parameters as their levels were changed 5

  16. 137Cs and 40K in some traditional herbal teas collected in the mountain regions of Serbia.

    PubMed

    Mitrović, Branislava M; Grdović, Svetlana N; Vitorović, Gordana S; Vitorović, Duško P; Pantelić, Gordana K; Grubić, Goran A

    2014-01-01

    Herbal teas are an important part of traditional medicine in Serbia. The objective of the present study was to determine the activity concentrations of (40)K and (137)Cs in herbal tea, using the gamma spectroscopy method. The samples were collected during the period 2011-2012 in three mountain regions in Western and Central Serbia. The activity concentrations of (40)K and (137)Cs were found to be in the range of 130-1160 and 0.7-124 Bq kg(-1), respectively. The average annual effective dose equivalents from ingestion of (40)K and (137)Cs for an adult person consuming one cup of herbal tea daily were found to be 588.4-5250.2 nSv for (40)K and 4.0-706.1 nSv for (137)Cs. Our investigation showed that the herbal teas originating from Maljen, Zlatibor and Tara mountains are radiologically safe for human consumption. PMID:25322769

  17. Sub-Doppler laser cooling of fermionic 40K atoms in three-dimensional gray optical molasses

    NASA Astrophysics Data System (ADS)

    Rio Fernandes, D.; Sievers, F.; Kretzschmar, N.; Wu, S.; Salomon, C.; Chevy, F.

    2012-12-01

    We demonstrate sub-Doppler cooling of 40K on the D1 atomic transition. Using a gray-molasses scheme, we efficiently cool a compressed cloud of 6.5 × 108 atoms from ˜4 mK to 20 μK in 8 ms. After transfer to a quadrupole magnetic trap, we measure a phase space density of ˜10-5. This technique offers a promising route for fast evaporation of fermionic 40K.

  18. Radioactive secular equilibrium in ²³⁸U and ²³²Th series in granitoids from Greece.

    PubMed

    Papadopoulos, A; Christofides, G; Koroneos, A; Stoulos, S; Papastefanou, C

    2013-05-01

    Granitoid rocks belonging to plutons of Greece, covering a wide range of compositions and rock-types, have been studied for their specific activity (Bq/kg) of (238)U and (226)Ra from (238)U radioactive series and (228)Ra and (228)Th from (232)Th radioactive series by using gamma-ray spectroscopy. Results on the radioactive secular equilibrium of both (238)U and (232)Th radioactive series are presented by studying the (226)Ra/(238)U and (228)Ra/(228)Th ratios. The majority of the samples are in radioactive secular equilibrium for (226)Ra/(238)U ± 1σ. However, several samples exhibit (226)Ra/(238)U ratios significantly different from 1. The distortion of the secular equilibrium in the (226)Ra-(238)U isotopic system of those samples has occurred over the last 1 Ma, and can be associated with post-magmatic processes, mainly rock-water interactions. All studied samples have (228)Ra/(228)Th ratios equal to unity ±1σ. Consequently, they can be considered to be in secular equilibrium for the last 40 a. PMID:23501359

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

    PubMed

    Faanu, A; Lawluvi, H; Kpeglo, D O; Darko, E O; Emi-Reynolds, G; Awudu, A R; Adukpo, O K; Kansaana, C; Ali, I D; Agyeman, B; Agyeman, L; Kpodzro, R

    2014-01-01

    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

  20. Rotational Spectroscopy on Ultracold 23 Na40 K Ground State Molecules

    NASA Astrophysics Data System (ADS)

    Will, Sebastian; Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Zwierlein, Martin

    2016-05-01

    Ultracold molecules with controllable dipolar long-range interactions will open up new routes for quantum simulation and the creation of novel states of matter. In particular, the molecules' rich internal degrees of freedom allow for versatile control of intermolecular interactions by applying static electric and microwave fields. Starting from an ultracold, spin-polarized ensemble of trapped fermionic 23 Na40 K molecules in the absolute ground state, we perform microwave spectroscopy on the first rotationally excited state for a range of magnetic and electric fields. Extracting the rotational and hyperfine coupling constants, we comprehensively understand the observed spectra. Following the coherent transfer of the entire ensemble of chemically stable 23 Na40 K molecules to the first rotationally excited state, we observe a lifetime of more than 3 sec, comparable to the lifetime in the rovibrational ground state. The collisional stability of excited rotational states opens up intriguing prospects for the control of intermolecular van-der-Waals interactions via electric fields.

  1. (137)Cs, (40)K and (210)Po in marine mammals from the southern Baltic Sea.

    PubMed

    Ciesielski, Tomasz; Góral, Marta; Szefer, Piotr; Jenssen, Bjørn Munro; Bojanowski, Ryszard

    2015-12-15

    This study provides information on baseline concentrations of the radionuclides Cesium-137, Potassium-40 and Polonium-210 in sea mammals from the Baltic Sea. The radionuclides were analyzed in the liver, kidney and muscle of harbor porpoises, striped dolphins, and gray and ringed seals from the Polish coast by γ- and α-spectrometry. Median (137)Cs activities were 14.8, 13.2 and 23.2 Bq kg(-1) w.w. in the liver, kidney and muscles, respectively. Activities of (40)K and (210)Po in the respective tissues were found to be 79.1, 79.8 and 111 Bq kg(-1) for (40)K and 58.1, 59.2 and 32.9 Bq kg(-1) for (210)Po. The measured (137)Cs concentrations were extraordinarily high in comparison to those reported in sea mammals from other locations. However, dose assessments did not imply health effects from (137)Cs exposure in Baltic Sea mammals. Correlations between (137)Cs tissue activities and reported sea water concentrations highlight the potential use of marine mammals for biomonitoring purposes. PMID:26456908

  2. Creating Fermionic Ground State Molecules of 23Na40K with Strong Dipolar Interactions

    NASA Astrophysics Data System (ADS)

    Park, Jee; Wu, Cheng-Hsun; Schloss, Jennifer; Will, Sebastian; Zwierlein, Martin

    2013-05-01

    In our experiment, we work towards creating fermionic ground state molecules of 23Na40K with strong dipolar interactions. These molecules will be chemically stable in the rovibrational ground state, and will carry a large induced dipole moment of 2.72 Debye. Building up on our previous work, we have done photoassociation spectroscopy on the 23Na-40K mixture in order to understand the molecular excited state potentials and identify possible intermediate states for efficient STIRAP transfer of Feshbach molecules down to the absolute rovibrational ground state. In addition, our recent effort in doing two-photon spectroscopy to locate the absolute rovibrational ground state will be presented. Our work paves the way towards creating stable dipolar quantum gases, which will open up new avenues to quantum many-body phases with intriguing properties such as supersolidity and topological phases. This work was supported by the NSF, AFOSR-MURI and -PECASE, ARO-MURI, ONR YIP, DARPA YFA, a grant from the Army Research Office with funding from the DARPA OLE program and the David and Lucille Packard Foundation.

  3. Dynamic nuclear polarization at 40 kHz magic angle spinning.

    PubMed

    Chaudhari, Sachin R; Berruyer, Pierrick; Gajan, David; Reiter, Christian; Engelke, Frank; Silverio, Daniel L; Copéret, Christophe; Lelli, Moreno; Lesage, Anne; Emsley, Lyndon

    2016-04-21

    DNP-enhanced solid-state NMR spectroscopy under magic angle spinning (MAS) is rapidly developing into a powerful analytical tool to investigate the structure of a wide range of solid materials, because it provides unsurpassed sensitivity gains. Most developments and applications of DNP MAS NMR were so far reported at moderate spinning frequencies (up to 14 kHz using 3.2 mm rotors). Here, using a 1.3 mm MAS DNP probe operating at 18.8 T and ∼100 K, we show that signal amplification factors can be increased by up to a factor two when using smaller volume rotors as compared to 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz. Spinning at 40 kHz is also shown to increase (29)Si coherence lifetimes by a factor three as compared to 10 kHz, substantially increasing sensitivity in CPMG type experiments. The contribution of quenching effects to the overall sensitivity gain at very fast MAS is evaluated, and applications are reported on a functionalised mesostructured organic-inorganic material. PMID:27035630

  4. Activity levels of 137Cs and 40K in the skin and the cutaneous organs of a cow.

    PubMed

    Pichl, Elke; Rabitsch, Herbert

    2003-08-01

    We have performed an extensive study to determine the activity distributions of radiocesium (137Cs) and of the radioisotope 40K of potassium in the whole body of a cow. ICRP assumes that cesium and potassium are distributed homogeneously throughout the whole body of an organism. The current investigation measured concentrations of 137Cs and 40K in components of the skin, horns, and hooves of a cow. Activity levels of 137Cs were caused by the long-term ingestion following the Chernobyl fallout, whereas the naturally occurring potassium (40K) is an essential part of cow's normal diet. The cow was born at the time of the fallout following the Chernobyl accident and had ingested heavily contaminated forage during its entire lifetime. Activities of 137Cs and 40K were determined simultaneously by gamma spectrometry. All activities are related to the day of slaughter and include also corrections for self attenuation of photons caused by the different densities of the samples. Radionuclide concentrations in samples were corrected for moisture losses incurred during freezing and sample preparation. Surface contamination on the skin was estimated by rinsing it in heated water followed by removal of the epidermis and hair. In comparison with the activities of the components of the skin we observed a considerable amount of external contamination on the surface of the skin. But with respect to whole body countings of the animal this amount of external contamination appears to be negligible. It was found that activity ratios of 137Cs to 40K are greater than 1 in all measured components. The average activity concentrations of 137Cs and 40K in the common integument are 23.3 Bq kg(-1) and 13.3 Bq kg(-1), respectively. The highest activity concentrations of 137Cs and 40K were measured in clean hair and hypodermis. Despite being its largest organ, the cow's skin contains probably less than 1% of the animal's whole body 137Cs activity. PMID:12938962

  5. Preoperative whole pelvic external irradiation in Stage I endometrial cancer. [/sup 60/Co; /sup 226/Ra

    SciTech Connect

    Ritcher, N.; Lucas, W.E.; Yon, J.L.; Sanford, F.G.

    1981-07-01

    Between 1966 and 1978, 201 patients with adenocarcinoma of the endometrium were treated at two hospitals in San Diego. Of these patients, 161 had disease limited to the corpus at the time of diagnosis. The majority of these patients received external whole-pelvic irradiation, followed as soon as possible by simple extrafascial hysterectomy and bilateral salpingo-oophorectomy. When this treatment method was used, actuarial survivals of 95% for Stage I disease were achieved. Also reported is the low incidence of wound complications in the group of patients operated soon after cessation of irradiation. The patients treated in this fashion had good survival rates, little morbidity from the adjunctive irradiation, and fewer wound complications than previously anticipated.

  6. Complete genome sequence of Stackebrandtia nassauensis type strain (LLR-40K-21T)

    SciTech Connect

    Munk, Chris; Lapidus, Alla; Copeland, Alex; Jando, Marlen; Mayilraj, Shanmugam; Glavina Del Rio, Tijana; Nolan, Matt; Chen, Feng; Lucas, Susan; Tice, Hope; Cheng, Jan-Fang; Han, Cliff; Detter, John C.; Bruce, David; Goodwin, Lynne; Chain, Patrick; Pitluck, Sam; Göker, Markus; Ovchinikova, Galina; Pati, Amrita; Ivanova, Natalia; Mavromatis, Konstantinos; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jeffries, Cynthia D.; Bristow, Jim; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter

    2009-12-30

    Stackebrandtia nassauensis Labeda and Kroppenstedt (2005) is the type species of the genus Stackebrandtia, and a member of the actinobacterial family Glycomycetaceae. Stackebrandtia currently contains two species, which are differentiated from Glycomyces spp. by cellular fatty acid and menaquinone composition. Strain LLR-40K-21T is Gram-positive, aerobic, and nonmotile, with a branched substrate mycelium and on some media an aerial mycelium. The strain was originally isolated from a soil sample collected from a road side in Nassau, Bahamas. We describe the features of this organism, together with the complete genome sequence and annotation. Lastly, this is the first complete genome sequence of the actinobacterial suborder Glycomycineae. The 6,841,557 bp long single replicon genome with its 6487 protein-coding and 53 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  7. Life-long accumulation of 137Cs and 40K in the vertebral column of a cow.

    PubMed

    Pichl, Elke; Rabitsch, Herbert

    2013-01-01

    We have investigated the accumulation of (137)Cs and (40)K in all the tissues and organs of an adult slaughtered Austrian "mountain pasture cow". In this paper we present measured (137)Cs- and (40)K-activity concentrations in different tissues of the vertebral bodies, in their other bony components and in all the vertebrae forming the vertebral column. Data are also given for activity concentrations of adherent tissues, and for activities of both the components and the whole vertebral column. The dairy cow was born in a highly contaminated region of Styria, Austria, at the time of the radioactive fallout following the Chernobyl accident. Both radionuclides were incorporated during life-long ingestion and their accumulation in all the vertebrae up to the day of slaughtering was determined by high-purity germanium detectors. Our results show considerable variations of (137)Cs- and (40)K-activity concentrations in the components of a certain vertebra, within vertebrae of a particular region, and between vertebrae of different regions of the vertebral column. Particularly, the courses of (137)Cs- and (40)K-activity concentrations in trabecular bone, cortical bone and intervertebral discs of thoracic vertebral bodies are subdivided by a strong drop into two sections. Mean values of (137)Cs-concentration in vertebral bodies of these subsections vary by a factor 4. Compared with corresponding quantities for the skeleton, total mass, as well as total (137)Cs- and (40)K-activities of the whole vertebral column came to 14%, and approximately 38% for each (137)Cs and (40)K, respectively. PMID:22943884

  8. Distribution and transport of radionuclides in a boreal mire--assessing past, present and future accumulation of uranium, thorium and radium.

    PubMed

    Lidman, Fredrik; Ramebäck, Henrik; Bengtsson, Åsa; Laudon, Hjalmar

    2013-07-01

    The spatial distribution of (238)U, (226)Ra, (40)K and the daughters of (232)Th, (228)Ra and (228)Th, were measured in a small mire in northern Sweden. High activity concentrations of (238)U and (232)Th (up to 41 Bq (238)U kg(-1)) were observed in parts of the mire with a historical or current inflow of groundwater from the surrounding till soils, but the activities declined rapidly further out in the mire. Near the outlet and in the central parts of the mire the activity concentrations were low, indicating that uranium and thorium are immobilized rapidly upon their entering the peat. The (226)Ra was found to be more mobile with high activity concentrations further out into the mire (up to 24 Bq kg(-1)), although the central parts and the area near the outlet of the mire still had low activity concentrations. Based on the fluxes to and from the mire, it was estimated that approximately 60-70% of the uranium and thorium entering the mire currently is retained within it. The current accumulation rates were found to be consistent with the historical accumulation, but possibly lower. Since much of the accumulation still is concentrated to the edges of the mire and the activities are low compared to other measurements of these radionuclides in peat, there are no indications that the mire will be saturated with respect to radionuclides like uranium, thorium and radium in the foreseen future. On the contrary, normal peat growth rates for the region suggest that the average activity concentrations of the peat currently may be decreasing, since peat growth may be faster than the accumulation of radionuclides. In order to assess the total potential for accumulation of radionuclides more thoroughly it would, however, be necessary to also investigate the behaviour of other organophilic elements like aluminium, which are likely to compete for binding sites on the organic material. Measurements of the redox potential and other redox indicators demonstrate that uranium possibly

  9. Radionuclide concentrations in raw and purified phosphoric acids from Brazil and their processing wastes: implications for radiation exposures.

    PubMed

    da Conceição, Fabiano Tomazini; Antunes, Maria Lúcia Pereira; Durrant, Steven F

    2012-02-01

    . Considering these annual additions of (238)U, (226)Ra, (232)Th and (40)K, and since these radionuclide should be homogeneously distributed in the upper 10 cm of soils with an assumed apparent density of 1.5 g/cm(3), a maximum increase of 0.19 ± 0.03 Bq kg(-1) of soil is expected for (238)U and (234)U. Thus, the addition of solid waste as phosphate fertilizers to Brazilian agricultural soils does not represent a hazard to the ecosystem or to human health. PMID:21614483

  10. The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

    PubMed

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-12-01

    The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides

  11. 40K-40Ca systematics as a Tracer of Silicate Weathering: A Himalayan case study

    NASA Astrophysics Data System (ADS)

    Davenport, Jesse; Caro, Guillaume; France-Lanord, Christian

    2015-04-01

    This study investigates the use of the 40K-40Ca system as a tracer to better quantify the contributions of silicate and carbonate lithologies in the dissolved load of major Himalayan rivers. Previous work using Sr isotopes as a proxy for silicate weathering has been complicated by the redistribution of radiogenic 87Sr between silicate and carbonate lithologies, particularly in the Lesser Himalaya, where dolomites exhibit 87Sr/86Sr ratios as high as 0.85. The 40Ca signature of carbonates, on the other hand, appears to be remarkably resistant to metamorphism and dolomitization [1]. It was therefore anticipated that the 40K-40Ca system could circumvent issues associated with such secondary events, and yield more robust constraints on the relative contribution of silicate vs. carbonate lithologies in dissolved river loads. The main difficulty in applying the 40K-40Ca decay scheme as a tracer lies in the analytical precision required to measure small variations (~1 ɛ-unit) on the large 40Ca isotope (96.9%). This difficulty can now be overcome using the Finnigan Triton TIMS, which allows measurements of the 40Ca/44Ca ratio with external precision of 0.35 ɛ-unit in multidynamic mode. Using this method, we generated high-precision 40Ca data on carbonates/dolomites, bedload sediments, dissolved load, and clay samples originating from and representing the main litho-tectonic units of the Himalaya. Our results show that metamorphosed dolomites from the Lesser Himalaya (LH) exhibit no radiogenic 40Ca excess despite highly variable 87Sr/86Sr signatures (0.73-0.85). Thus, all Himalayan carbonates appear to be characterized by a homogeneous ɛ40Ca=0. In contrast, silicate material is radiogenic, with ɛ40Ca averaging +1 in the Tethyan Sedimentary Series (TSS), +1.6 in the High Himalaya crystalline (HHC) and +4 ɛ-units in the LH. Results obtained from a series of 35 Himalayan rivers (including the Brahmaputra, Ganga and its main tributaries) show that ɛ40Ca in the

  12. Short-lived decay series disequilibria in the natrocarbonatite lavas of Oldoinyo Lengai, Tanzania: constraints on the timing of magma genesis

    NASA Astrophysics Data System (ADS)

    Pyle, D. M.; Dawson, J. B.; Ivanovich, M.

    1991-08-01

    The 1988 natrocarbonatite lavas from Oldoinyo Lengai volcano, Tanzania have been analysed for 232Th, 230Th, 228Th, 238U, 228Ra/ 226Ra. These lavas are unique, in showing disequilibria between 228Th/ 232Th, and between 228Ra and 232Th. Aa and pahoehoe lavas have a mean ( 228Th 232Th) activity ratio of 5.5 ± 0.6 , and one lava has ( 228Ra/ 226Ra) = 0.11 ± 0.01 . The lavas have ( 230Th/ 238U) ˜ 0.1-0.2 , and [ UTh] weight ratios of 2.0-3.2. Late-stage samples, extruded from the lavas on cooling and interpreted as extreme fractionates of the original lavas are highly enriched in U and Ra relative to Th. These samples have measured [ UTh] weight ratios of 5.6-6.4, and a calculated ( 228Ra/ 232Th) activity ratio of 108 ± 5 . Disequilibria between 238U&z.sbnd; 230Th&z.sbnd; 226Ra are consistent with an origin by immiscibility of 4-22wt% natrocarbonatite from nephelinite magma. Disequilibria between 232Th&z.sbnd; 228Ra&z.sbnd; 228Th are consistent with either of two endmember models: (1) instantaneous separation of magma at depth, with eruption 20 ± 1 years later; (2) recharging of a steady-state magma chamber below Oldoinyo Lengai with a maximum volume of 1.5 ± 0.2 × 10 7 m 3 of carbonatite, and a mean magma residence time of 81 ± 9 years. The total time between natrocarbonatite generation and eruption is between 20 and 81 years.

  13. Assessment of Annual Effective Dose for Natural Radioactivity of Gamma Emitters in Biscuit Samples in Iraq.

    PubMed

    Abojassim, Ali Abid; Al-Alasadi, Lubna A; Shitake, Ahmed R; Al-Tememie, Faeq A; Husain, Afnan A

    2015-09-01

    Biscuits are an important type of food, widely consumed by babies in Iraq and other countries. This work uses gamma spectroscopy to measure the natural radioactivity due to long-lived gamma emitters in children's biscuits; it also estimates radiation hazard indices, that is, the radium equivalent activity, the representative of gamma level index, the internal hazard index, and the annual effective dose in children. Ten samples were collected from the Iraqi market from different countries of origin. The average specific activities for (226)Ra, (232)Th, and (40)K were 9.390, 3.1213, and 214.969 Bq/kg, respectively, but the average of the radium equivalent activity and the internal hazard index were 33.101 Bq/kg and 0.107, respectively. The total average annual effective dose from consumption by adults, children, and infants is estimated to be 0.655, 1.009, and 0.875 mSv, respectively. The values found for specific activity, radiation hazard indices, and annual effective dose in all samples in this study were lower than worldwide median values for all groups; therefore, these values are found to be safe. PMID:26319734

  14. Determination and mapping the spatial distribution of radioactivity of natural spring water in the Eastern Black Sea Region by using artificial neural network method.

    PubMed

    Yeşilkanat, Cafer Mert; Kobya, Yaşar

    2015-09-01

    In this study, radiological distribution of gross alpha, gross beta, (226)Ra, (232)Th, (40)K, and (137)Cs for a total of 40 natural spring water samples obtained from seven cities of the Eastern Black Sea Region was determined by artificial neural network (ANN) method. In the ANN method employed, the backpropagation algorithm, which estimates the backpropagation of the errors and results, was used. In the structure of ANN, five input parameters (latitude, longitude, altitude, major soil groups, and rainfall) were used for natural radionuclides and four input parameters (latitude, longitude, altitude, and rainfall) were used for artificial radionuclides, respectively. In addition, 75 % of the total data were used as the data of training and 25 % of them were used as test data in order to reveal the structure of each radionuclide. It has been seen that the results obtained explain the radiographic structure of the region very well. Spatial interpolation maps covering the whole region were created for each radionuclide including spots not measured by using these results. It has been determined that artificial neural network method can be used for mapping the spatial distribution of radioactivity with this study, which is conducted for the first time for the Black Sea Region. PMID:26307690

  15. Radiometric analysis of construction materials using HPGe gamma-ray spectrometry.

    PubMed

    Khandaker, M U; Jojo, P J; Kassim, H A; Amin, Y M

    2012-11-01

    Concentrations of primordial radionuclides in common construction materials collected from the south-west coastal region of India were determined using a high-purity germanium gamma-ray spectrometer. Average specific activities (Bq kg(-1)) for (238)U((226)Ra) in cement, brick, soil and stone samples were obtained as 54 ± 13, 21 ± 4, 50 ± 12 and 46 ± 8, respectively. Respective values of (232)Th were obtained as 65 ± 10, 21 ± 3, 58 ± 10 and 57 ± 12. Concentrations of (40)K radionuclide in cement, brick, soil and stone samples were found to be 440 ± 91, 290 ± 20, 380 ± 61 and 432 ± 64, respectively. To evaluate the radiological hazards, radium equivalent activity, various hazard indices, absorbed dose rate and annual effective dose have been calculated, and compared with the literature values. Obtained data could be used as reference information to assess any radiological contamination due to construction materials in future. PMID:22887119

  16. Natural radioactivity levels and radiation hazard indices in granite from Aswan to Wadi El-Allaqi southeastern desert, Egypt.

    PubMed

    El-Taher, A; Uosif, M A M; Orabi, A A

    2007-01-01

    Studies on radiation level and radionuclide distribution in granite from Aswan to Wadi El-Allaqi area that is located in southeastern desert of Egypt were undertaken. The samples collected from five locations: Gabal El Mesala, Umm Hibal, Abu Herigle, Abu Marw and Deneibit El Quleib. The purpose of this study is to provide a baseline map of radioactivity background levels in the investigated area environment, and this study will be used as reference information to assess any changes in the radioactive background level due to geological processes. The highest average values of 226Ra and 232Th concentrations (24.00 and 31.28 Bq kg(-1), respectively) were observed at Abu Herigle region, whereas the highest average value of 40K concentration, 589.95 Bq kg(-1), was detected in Umm Hibal. The absorbed dose rate in air was found to be in the range between 5.40 and 45.11 nGy h(-1), and radium equivalent activity concentration was found in the range between 29.57 and 71.85 Bq kg(-1). Also the representative external hazard index values for the corresponding samples were also estimated and given. PMID:17569689

  17. Radioactivities related to coal mining.

    PubMed

    Seddeek, Mostafa K; Sharshar, Taher; Ragab, Hossam S; Badran, Hussein M

    2005-08-01

    Natural radioactivity concentrations due to the coal mining in Gabal El-Maghara, North Sinai, Egypt, were determined using gamma-ray spectroscopy. Coal, water and soil samples were investigated in this study. The (226)Ra, (232)Th and (40)K activity concentrations in coal before extraction were 18.5 +/- 0.5, 29.5 +/- 1.2 and 149.0 +/- 8.4 Bq kg(-1), respectively. These concentrations were reduced to 18-22% after extraction due to the clay removal of the coal ore. The activity contents of the water and soil samples collected from the surrounding area did not show any evidence of enhancement due to the mining activities. Absorbed dose rate and effective dose equivalent in the mine environment were 29.4 nGy h(-1) and 128.0 microSv a(-1), respectively. The measured activity concentrations in the mine environment and the surrounding areas (5 km away from the mine) are similar to that found in other regions in North and South Sinai. Based on the measurements of gamma-ray emitting radionuclides, the mine activity does not lead to any enhancement in the local area nor represents any human risk. PMID:16049576

  18. Radiation dose estimation of sand samples collected from different Egyptian beaches.

    PubMed

    Eissa, H S; Medhat, M E; Said, S A; Elmaghraby, E K

    2011-11-01

    A high pure germanium detector-based gamma-ray spectroscopy low-background counting system was used to determine the levels of natural radioactivity from beach sand samples on the Egyptian coast along the Mediterranean and Red Seas. The activity concentrations of (226)Ra, (232)Th and (40)K were found to lie in the range of 30±11 to 60±14 Bq kg(-1) with a mean of 39±15 Bq kg(-1), 12±3 to 30±14 Bq kg(-1) with a mean of 21±13 Bq kg(-1) and 392±22 to 413±22 Bq kg(-1) with a mean of 402±23 Bq kg(-1), respectively. Radiation hazard indices and annual effective doses were evaluated and compared with the international data. The results indicate that the values obtained fall below the internationally accepted maximum limits and do not pose any significant radiation hazard to individuals in the study area. From these results, a radiological baseline map of Egyptian beaches can be drawn and used as reference information to assess any future alterations in the radioactivity of beach sands due to any changes in the sea sediments. PMID:21169289

  19. Radiometric assessment of natural radioactivity levels of agricultural soil samples collected in Dakahlia, Egypt.

    PubMed

    Issa, Shams A M

    2013-01-01

    Determination of the natural radioactivity has been carried out, by using a gamma-ray spectrometry [NaI (Tl) 3″ × 3″] system, in surface soil samples collected from various locations in Dakahlia governorate, Egypt. These locations form the agriculturally important regions of Egypt. The study area has many industries such as chemical, paper, organic fertilisers and construction materials, and the soils of the study region are used as a construction material. Therefore, it becomes necessary to study the natural radioactivity levels in soil to assess the dose for the population in order to know the health risks. The activity concentrations of (226)Ra, (232)Th and (40)K in the soil ranged from 5.7 ± 0.3 to 140 ± 7, from 9.0 ± 0.4 to 139 ± 7 and from 22 ± 1 to 319 ± 16 Bq kg(-1), respectively. The absorbed dose rate, annual effective dose rate, radium equivalent (Req), excess lifetime cancer risk, hazard indices (Hex and Hin) and annual gonadal dose equivalent, which resulted from the natural radionuclides in the soil were calculated. PMID:23509393

  20. Radioactivity and radiological risk associated with effluent sediment containing technologically enhanced naturally occurring radioactive materials in amang (tin tailings) processing industry.

    PubMed

    Bahari, Ismail; Mohsen, Nasirian; Abdullah, Pauzi

    2007-01-01

    The processing of amang, or tin tailings, for valuable minerals has been shown to technologically enhance NORM and this has stirred significant radiological safety and health concerns among Malaysia's regulatory authority. A growing radiological concern is now focused on the amang effluent containing NORM in recycling ponds, since these ponds may be reclaimed for future residential developments. A study was carried out to assess the radiological risk associated with amang processing and the accumulated effluent in the recycling ponds. Twenty-six sediment samples from the recycling ponds of two amang plants in the states of Selangor and Perak, Malaysia, were collected and analyzed. The maximum activity concentrations of (238)U, (226)Ra, (232)Th and (40)K recorded in sediments from these ponds were higher than Malaysia's and the world's natural highest. Correspondingly, the mean radium equivalent activity concentration indices, Ra(eq), and gamma radiation representative level index, I(gammar), were higher than the world's average. The enhancement of NORM in effluent sediments as a consequence of amang processing, and the use of a closed water management recycling system created Effective Dose Rates, E (nSv h(-1)), that signal potential environmental radiological risks in these ponds, should they be reclaimed for future land use. PMID:17428589

  1. Soil radioactivity levels and radiological risk assessment in the highlands of Hunza, Pakistan.

    PubMed

    Ali, Manzoor; Iqbal, Sajid; Wasim, Mohammad; Arif, Mohammad; Saif, Farhan

    2013-03-01

    This paper deals with the determination of (226)Ra, (232)Th, (40)K and (137)Cs in 42 soil samples collected from eight towns of Hunza district, at an average altitude of 2267 m, using gamma-ray spectrometry. The activity concentration data were analysed for frequency distribution and other descriptive measures. Risk assessment was done by calculating the hazard indices, air absorbed dose rate and external annual effective dose rate due to cosmic radiations, terrestrial radionuclides and (137)Cs deposited on the surface of the earth. Both indoor and outdoor occupancy factors were taken into account. The average dose rate due to cosmic radiation was estimated as 828 ± 87 µSv y(-1), from external terrestrial radiation as 97 ± 20 µSv y(-1) and from (137)Cs as 1.05 µSv y(-1) for a total annual effective dose rate of 926 ± 92 µSv. The results of the present study were discussed and compared with other similar studies performed in East Asia. The present study indicates that Hunza can be ranked among those areas having a high level of dose rate not only from cosmic rays but also from terrestrial radionuclides. This paper also proposes another measure of radiation hazard called 'radium equivalent for internal exposure'. PMID:22734067

  2. Estimation of annual effective dose due to natural and man-made radionuclides in the metropolitan area of the Bay of Cadiz (SW of Spain).

    PubMed

    Casas-Ruiz, M; Ligero, R A; Barbero, L

    2012-06-01

    In order to investigate the radiological hazard of naturally occurring radioactive material (NORM) and man-made (137)Cs radionuclide in the Bay of Cádiz, 149 samples of sediments have been analysed. Activity concentration in all the samples was determined using a HPGe detection system. Activity concentrations values of (226)Ra, (232)Th, (40)K and (137)Cs in the samples were 12.6±2.6 (2.5-40.6), 18.5±4.0 (2.8-73.4), 451±45 (105-1342) and 3.2±1.3 (0.2-16.0) Bq kg(-1), respectively. Outdoor external dose rate due to natural and man-made radionuclides was calculated to be 35.79±1.69 (4.71-119.16) nGy h(-1) and annual effective dose was estimated to be 43.89±2.27 (5.78-146.14) µSv y(-1). Results showed low levels of radioactivity due to NORM and man-made (137)Cs radionuclide in marine sediments recovered from the Bay of Cádiz (Spain), discarding any significant radiological risks related to human activities of the area. Furthermore, the obtained data set could be used as background levels for future research. PMID:21896553

  3. Measurement of physiochemical parameters and determination of the level of radiological threat to the population associated with the Karnaphuli River sediment containing municipal and industrial wastes of Chittagong city in Bangladesh.

    PubMed

    Alam, Md Kowsar; Chakraborty, Shyamal Ranjan; Rahman, Abul Khaer Mohammad Rezaur; Deb, Arun Kumar; Kamal, Masud; Chowdhury, Mantazul Islam; Uddin, Md Suza

    2013-03-01

    The research work has been aimed to assess the radiological and chemical threat caused due to urban and industrial wastage drainage to the inhabitants of the Chittagong city in Bangladesh. For finding the chemical effects along with the measurement of radiological threat, the physiochemical characteristics (temperature, pH value and oxidation-reduction potential) of the sediment samples have been analysed. The activity concentrations of naturally occurring radionuclides (238)U, (232)Th, (226)Ra and (40)K in the investigated samples have been found to be higher than those of the world average values. The artificial radionuclide (137)Cs in the samples studied has not been detected. The mean value of the radium equivalent activity and outdoor exposure rate in the study region have been found to be 240.94 ± 23.12 Bq kg(-1) and 115.82 ± 10.81 nGy h(-1), respectively. The radiation doses have been measured directly by employing beta-gamma survey meter (model: LUDLUM 44-9) from where the samples have been collected. The average values of the radiological parameters have been calculated from the activity concentrations of the radionuclides mentioned in the sediment samples found to be higher than those of the corresponding world average values. PMID:22807494

  4. Radiation dose estimation and mass attenuation coefficients of cement samples used in Turkey.

    PubMed

    Damla, N; Cevik, U; Kobya, A I; Celik, A; Celik, N; Van Grieken, R

    2010-04-15

    Different cement samples commonly used in building construction in Turkey have been analyzed for natural radioactivity using gamma-ray spectrometry. The mean activity concentrations observed in the cement samples were 52, 40 and 324 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and world average limits. The radiological hazard parameters such as radium equivalent activities (Ra(eq)), gamma index (I(gamma)) and alpha index (I(alpha)) indices as well as terrestrial absorbed dose and annual effective dose rate were calculated and compared with the international data. The Ra(eq) values of cement are lower than the limit of 370 Bq kg(-1), equivalent to a gamma dose of 1.5 mSv y(-1). Moreover, the mass attenuation coefficients were determined experimentally and calculated theoretically using XCOM in some cement samples. Also, chemical compositions analyses of the cement samples were investigated. PMID:20018450

  5. GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS: Assessment of Primordial Radionuclides in Pakistani Red Bricks and Associated Radiation Doses

    NASA Astrophysics Data System (ADS)

    Khan, K.; Jabbar, A.; Akhter, P.; Tufail, M.; Khan M., H.

    2010-03-01

    Specific activity of primordial radionuclides and associated radiation hazards due to 40K, 226Ra, and 232Th have been measured in backed red brick samples, collected from five highly populated areas of the North West Frontier Province of Pakistan. For the detection, analysis and data acquisition, a high purity germanium detector was used. Associated external doses were calculated using a Monte Carlo neutron photon transport code. A theoretical model to determine the gamma dose rate at 1 m height from the floor, made of bricks, was employed for the calculation of mass attenuation coefficient and self-absorption in the floor for the gamma energies of these radionuclides and their progeny. Monte Carlo simulation shows that in this study the floor, having more than an effective thickness of 15 cm, contributes very little to the external gamma dose rate. The values of the external dose rate and annual effective dose are found to be much lower than the world average as well as from other countries of the world.

  6. Radiological risk assessment of natural radionuclides in sand collected from some beaches along the coastline of southwestern Nigeria.

    PubMed

    Ademola, J A; Nwafor, C O

    2013-10-01

    The activity concentrations of natural radionuclides in sand from three beaches in southwestern Nigeria had been determined employing the gamma-ray spectroscopy method. The mean activity concentrations of (226)Ra, (232)Th and (40)K, respectively, were 12.5 ± 3.3, 25.8 ± 4.7 and 153.9 ± 18.5 Bq kg(-1) for Suntan Beach, 13.1 ± 3.1, 23.9 ± 4.5 and 219.9 ± 33.9 Bq kg(-1) for Bar Beach. Lekki Beach had 13.2 ± 3.2, 26.3 ± 3.8 and 149.0 ± 19.8 Bq kg(-1), respectively. The absorbed dose rates were calculated as 27.8 ± 3.1, 29.7 ± 4.0, 28.2 ± 3.3 nGy h(-1), respectively. The corresponding annual effective doses are 0.034 ± 0.004, 0.036 ± 0.005, 0.035 ± 0.004 mSv y(-1), which are less than the limit of 1 mSv y(-1) recommended for the members of the public. The radiological hazard indices are within the maximum recommended limits, hence pose no significant radiological hazards for construction. PMID:23567195

  7. Radioactivity in Montenegro beach sands and assessment of the corresponding environmental risk.

    PubMed

    Antovic, Nevenka M; Svrkota, Nikola; Antovic, Ivanka; Svrkota, Ranko; Jancic, Dejan

    2013-06-01

    Activity concentrations of the naturally occurring radionuclides (226)Ra, (232)Th, (40)K and anthropogenic (137)Cs in sand samples collected from 20 renowned beaches on the Coast of Montenegro have been determined using an HPGe (high purity Ge spectrometer). The average activity concentrations were found to be 7.4, 5.2, 97.3 and 0.5 Bq kg(-1), respectively. For all sand samples, the radium equivalent activity has been evaluated and found to be lower than the limit of 370 Bq kg(-1). External and internal hazard indices were less than unity. The gonadal dose equivalent was estimated to be on average 75 μSv y(-1), which is about four times lower than the global average for soil (0.3 mSv y(-1)). Calculated values of absorbed dose rates showed the range from 3.1 to 28 nGy h(-1), which is below the world median of average values (57 nGy h(-1)). The effective dose rate in the range from 3.8 to 34.4 μSv y(-1) was significantly below the recommended limit value for the public (1 mSv y(-1)). The highest dose rate was found for the Velika Plaza locality, which also showed heavy metal contents (As, B, Cd, Hg, Cr, Cu, Mn, Ni, Pb, Zn and Ba) significantly higher than in the sand from Jaz, a locality with one of the lowest dose rates. PMID:23452289

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

    PubMed

    Murat Saç, Müslim; Aydemir, Sercan; Içhedef, Mutlu; Kumru, Mehmet N; Bolca, Mustafa; Ozen, Fulsen

    2014-01-01

    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). PMID:24026900

  9. Assessment of radionuclides in the soil of residential areas of the Chittagong metropolitan city, Bangladesh and evaluation of associated radiological risk

    PubMed Central

    Rashed-Nizam, Quazi Muhammad; Rahman, Md. Mashiur; Kamal, Masud; Chowdhury, Mantazul Islam

    2015-01-01

    Soil samples from the three residential hubs of Chittagong city, Bangladesh were analyzed using gamma spectrometry to estimate radiation hazard due to natural radioactive sources and anthropogenic nuclide 137Cs. The activity concentration of 226Ra was found to be in the range 11–25 Bq.kg−1, 232Th in the range 38–59 Bq.kg−1 and 40K in the range 246–414 Bq.kg−1. These results were used to calculate the radiological hazard parameters including Excess of Lifetime Cancer Risk (ELCR). The estimated outdoor gamma exposure rates were 40.6–63.8 nGy.h−1. The radiation hazard index (radium equivalent activity) ranged from 90–140 Bq.kg−1. The average value of the ELCR was found to be 0.21 × 10−3, which is lower than the world average. Sporadic fallout of 137Cs was observed with an average value of 2.0 Bq.kg−1. PMID:25237039

  10. Radioactivity in food crops

    SciTech Connect

    Drury, J.S.; Baldauf, M.F.; Daniel, E.W.; Fore, C.S.; Uziel, M.S.

    1983-05-01

    Published levels of radioactivity in food crops from 21 countries and 4 island chains of Oceania are listed. The tabulation includes more than 3000 examples of 100 different crops. Data are arranged alphabetically by food crop and geographical origin. The sampling date, nuclide measured, mean radioactivity, range of radioactivities, sample basis, number of samples analyzed, and bibliographic citation are given for each entry, when available. Analyses were reported most frequently for /sup 137/Cs, /sup 40/K, /sup 90/Sr, /sup 226/Ra, /sup 228/Ra, plutonium, uranium, total alpha, and total beta, but a few authors also reported data for /sup 241/Am, /sup 7/Be, /sup 60/Co, /sup 55/Fe, /sup 3/H, /sup 131/I, /sup 54/Mn, /sup 95/Nb, /sup 210/Pb, /sup 210/Po, /sup 106/Ru, /sup 125/Sb, /sup 228/Th, /sup 232/Th, and /sup 95/Zr. Based on the reported data it appears that radioactivity from alpha emitters in food crops is usually low, on the order of 0.1 Bq.g/sup -1/ (wet weight) or less. Reported values of beta radiation in a given crop generally appear to be several orders of magnitude greater than those of alpha emitters. The most striking aspect of the data is the great range of radioactivity reported for a given nuclide in similar food crops with different geographical origins.

  11. Evaluation of natural radionuclides in Brazilian underground mines

    NASA Astrophysics Data System (ADS)

    Santos, T. O.; Rocha, Z.; Vasconcelos, V.; Lara, E. G.; Palmieri, H. E. L.; Cruz, P.; Gouvea, V. A.; Siqueira, J. B.; Oliveira, A. H.

    2015-11-01

    Mineral processing releases long and short half-life radionuclides generating potential exposure to miners. They are internally exposed to radon, thoron and their short-life decay products and, externally, to the gamma emitters scattered in the rock and dust of the mine. Concerning to radiological hazards to workers, this paper focuses on the characterization of the natural radioactivity in the Brazilian underground mines. The radon and its progeny concentrations were measured by using AlphaGUARD and DOSEman detectors, respectively. Radon concentration measurement in groundwater was performed by using RAD7 detector. The 238U and 232Th activity concentration in ore and soil samples were determined by ICPMS. Gamma spectrometry was used to determined 226Ra, 228Ra and 40K activity concentrations. The average radon concentration ranged from 113 to 4964 Bq m-3 and the average Equilibrium Equivalent Concentration varied from 76 to 1174 Bq m-3. Based on these data, the total annual effective dose for the miners was estimated. The results suggest the need of establishing monitoring and control procedures in some mines.

  12. Radon levels in groundwaters and natural radioactivity in soils of the volcanic region of La Garrotxa, Spain.

    PubMed

    Moreno, V; Bach, J; Baixeras, C; Font, Ll

    2014-02-01

    Groundwater radon level and soil radionuclide concentration have been measured in the volcanic region of La Garrotxa (Catalonia, Spain) to further research on the origin and dynamics of high radon levels over volcanic materials found in this region. Water samples from different aquifers have been collected from wells and springs and the water radon levels obtained have been lower than 30 Bq l(-1). Soil samples have been collected from different geological formations (volcanic and non-volcanic), being Quaternary sedimentary deposits those that have presented the highest mean values of (40)K, (226)Ra and (232)Th concentrations (448 ± 70 Bq kg(-1), 35 ± 5 Bq kg(-1) and 38 ± 5 Bq kg(-1), respectively). Additionally, indoor/outdoor terrestrial radiation absorbed dose rate in air have been measured to better characterize the region from the radiological point of view. Terrestrial radiation absorbed dose rates measurement points have been chosen on the basis of geological and demographical considerations and the results obtained, from 27 to 91 nGy h(-1), show a clear relation with geological formation materials. The highest terrestrial gamma absorbed dose rate is observed over Quaternary sedimentary deposits as well. All these results help to better understand previous surveys related with indoor and outdoor radon levels and to reinforce the hypotheses of a radon transport through the fissure network. PMID:24239577

  13. Environmental radioactivity in southern Serbia at locations where depleted uranium was used.

    PubMed

    Sarap, Nataša B; Janković, Marija M; Todorović, Dragana J; Nikolić, Jelena D; Kovačević, Milojko S

    2014-06-01

    In the 1999 bombing of the Federal Republic of Yugoslavia, NATO forces used ammunition containing depleted uranium. The cleaning of depleted uranium that followed was performed in southern Serbia by the Vinča Institute of Nuclear Sciences between 2002 and 2007 at the locations of Pljačkovica, Borovac, Bratoselce, and Reljan. This paper presents detailed results of radioactivity monitoring four years after cleaning (2011), which included the determination of gamma emitters in soil, water, and plant samples, as well as gross alpha and beta activities in water samples. The gamma spectrometry results showed the presence of natural radionuclides 226Ra, 232Th, 40K, 235U, 238U, and the produced radionuclide 137Cs (from the Chernobyl accident). In order to evaluate the radiological hazard from soil, the radium equivalent activity, the gamma dose rate, the external hazard index, and the annual effective dose were calculated. Considering that a significant number of people inhabit the studied locations, the periodical monitoring of radionuclide content is vital. PMID:24778342

  14. Characteristics of NORM in the oil industry from eastern and western deserts of Egypt.

    PubMed

    Shawky, S; Amer, H; Nada, A A; El-Maksoud, T M; Ibrahiem, N M

    2001-07-01

    Naturally occurring radionuclides (NORs) from the 232Th- and 238U-series, which are omnipresent in the earth's crust, can be concentrated by technical activities, particularly those involving natural resources. Although, a great deal of work has been done in the field of radiation protection and remedial action on uranium and other mines, recent concern has been devoted to the hazard arising from naturally occurring radioactive materials (NORM) in oil and gas facilities. NORM wastes associated with oil and gas operations from scale deposits, separated sludge and water at different oil fields in the eastern and western deserts were investigated. Concentrations of the uranium, thorium, and potassium (40K) series have been determined from high-resolution gamma-ray spectrometry. Total uranium content of samples was determined using laser fluorimetry. The levels of radioactivity were mainly due to enhanced levels of dissolved radium ions. Only minute quantities of uranium and thorium were present. The disequilibrium factor for 238U/226Ra has been determined. PMID:11339530

  15. Determination of natural radioactivity and associated radiation hazard in building materials used in Weinan, China

    NASA Astrophysics Data System (ADS)

    Lu, Xinwei; Chao, Shigang; Yang, Fang

    2014-06-01

    The concentrations of 226Ra, 232Th and 40K in the commonly used building materials of Weinan, China were measured using γ-ray spectrometry. The associated radiological hazards of natural radioactivity in the studied materials were evaluated by radium equivalent activity, external hazard index, internal hazard index, indoor air absorbed dose rate and annual effective dose rate. The measurement results show that the natural radionuclides contents of the studied building materials are in the range of Chinese soil values. The radium equivalent activity and external hazard index values of glazed tile are close to or higher than the recommended limit. The internal hazard index values and the annual effective dose rate values of roof tile, glazed tile and some cement samples made from fly ash are close to or higher than unity and 1 mSv y-1, respectively. The study shows that roof tile and glazed tile should be limited to use in the construction of building and the monitoring on the natural radioactivity level of cement made from fly ash should be intensified for avoiding unnecessary radiation exposure to residents.

  16. Elemental analysis of marble used in Saudi Arabia by different nuclear analytical techniques.

    PubMed

    El-Taher, A; Ibraheem, Awad A; Abdelkawy, Salah

    2013-03-01

    Instrumental neutron activation analysis (INAA) and HPGe detector γ-spectroscopy were used to determine a total of 22 elements qualitatively and quantitatively for the first time from marble rock samples collected from local markets in Saudi Arabia. The elements determined are Mg, Ca, V, Na, Mn, As, La, Sm, U, Sc, Cr, Fe, Co, Zn, Sn, Ba, Ce, Eu, Yb, Lu, Hf, and Th. The samples were properly prepared together with their standard reference material and simultaneously irradiated by thermal neutrons at the TRIGA Mainz research reactor at a neutron flux of 7 × 10(11) n/cm(2) s. XRF was also used. The concentrations of natural radionuclides (226)Ra, (232)Th and (40)K were also determined by gamma ray spectroscopy to estimate the radiological parameters such as radium equivalent activity, and the external hazard index was calculated to estimate the exposure risk from usage of marble as raw materials in construction. For the sake of comparison the results of concentration levels and radium equivalent activities are compared with similar studies carried out in other countries. PMID:23262125

  17. Radioenvironmental survey of the Megalopolis lignite field basin.

    PubMed

    Rouni, P K; Petropoulos, N P; Anagnostakis, M J; Hinis, E P; Simopoulos, S E

    2001-05-14

    The Megalopolis lignite field basin in southern Greece, with Megalopolis-A and B lignite-fired power plants in operation (total 900 MW), has been repeatedly investigated during the past 25 years by the Nuclear Engineering Section of the National Technical University of Athens (NES-NTUA). The present work aims at an integrated radioenvironmental approach leading to the dose assessment to the public and to the plants staff. This approach includes systematic sampling of lignite and barren at the local lignite mines feeding the power plants and sampling of lignite, fly-ash and bottom ash at the power plants for the determination of the activity of the natural radionuclides 226Ra, 232Th, 40K, 234Th and 210Pb. Furthermore, the following measurements and samplings were conducted in 25 selected sites within 10 km around the power plants: soil sampling for the determination of the above radionuclides, radon concentration and exhalation rate measurements, soil gas radon concentration measurements, dose measurements and calculations, determination of air-particulate matter concentration, etc. The results obtained allowed for the mapping of the parameters studied which lead to useful conclusions. Dosimetric calculations for the population living around the power plants and the plants staff were also performed based on the guidance of UNSCEAR (1982 report). PMID:11379921

  18. Specific activities of natural rocks and soils at quaternary intraplate volcanism north of Sana’a, Yemen

    PubMed Central

    Harb, Shaban; El-Kamel, Abd El-Hadi; Abbady, Abd El-Bast; Saleh, Imran Issa; El-Mageed, Abdallah Ibrahim Abd

    2012-01-01

    The level of natural radioactivity in rocks and soil of 32 samples collected from locations at North Sana′a in Yemen was measured. Concentrations of radionuclides in rocks and soils samples were determined by gamma-ray spectrometer using high purity germanium (HPGe) detector with specially designed shield. The average radioactivity concentrations of 226Ra, 232Th, 40K were determined and expressed in Bq/kg. The results showed that these radionuclides were present in concentrations of 21.79 ± 3.1, 19.5 ± 2.6 and 399.3 ± 16 Bq/kg, respectively, for rocks. For soil, the corresponding values were 48.2 ± 4.4, 41.7 ± 4.5 and 939.1 ± 36 Bq/kg, respectively. Also, the radiological hazard of the natural radionuclide content, radium equivalent activity, total dose rates, external hazard index and gamma activity concentration index of the (rocks/soils) samples in the area under consideration were calculated. The dose rates at 1 m above the ground from terrestrial sources were 38.39 and 86.89 nGy/h for rocks and surface soil, respectively, which present no significant health hazards to humans. PMID:22363113

  19. RangerMaster{trademark}: Real-time pattern recognition software for in-field analysis of radiation sources

    SciTech Connect

    Murray, W.S.; Ziemba, F.; Szluk, N.

    1998-12-31

    RangerMaster{trademark} is the embedded firmware for Quantrad Sensor`s integrated nuclear instrument package, the Ranger{trademark}. The Ranger{trademark}, which is both a gamma-ray and neutron detection system, was originally developed at Los Alamos National Laboratory for in situ surveys at the Plutonium Facility to confirm the presence of nuclear materials. The new RangerMaster{trademark} software expands the library of isotopes and simplifies the operation of the instrument by providing an easy mode suitable for untrained operators. The expanded library of the Ranger{trademark} now includes medical isotopes {sup 99}Tc, {sup 201}Tl, {sup 111}In, {sup 67}Ga, {sup 133}Xe, {sup 103}Pa, and {sup 131}I; industrial isotopes {sup 241}Am, {sup 57}Co, {sup 133}Ba, {sup 137}Cs, {sup 40}K, {sup 60}Co, {sup 232}Th, {sup 226}Ra, and {sup 207}Bi; and nuclear materials {sup 235}U, {sup 238}U, {sup 233}U, and {sup 239}Pu. To accomplish isotopic identification, a simulated spectrum for each of the isotopes was generated using SYNTH. The SYNTH spectra formed the basis for the knowledge-based expert system and selection of the regions of interest that are used in the pattern recognition system. The knowledge-based pattern recognition system was tested against actual spectra under field conditions.

  20. Geographical information systems and air pollution simulation for Megalopolis' electric power plant in Peloponnese, Greece.

    PubMed

    Theophanides, Mike; Anastassopoulou, Jane; Theophanides, Theophile

    2014-01-01

    The growth and sophistication of geographic information systems (GIS) have propelled us into a new era of environmental analyses. Air pollution is a growing concern in populated areas as many recent studies have associated high levels of pollution with increased illnesses and mortality. The study will focus on the toxicity levels incurred by radioactive lignite-burning Power Generation facilities located in Megalopolis, Greece. An estimate of pollution emissions followed by dispersion simulations for various atmospheric conditions will be given. The exercise will be integrated with a Geographical Information System (GIS) for defining the emission sources and visualizing the dispersion of pollutants over the geographical terrain. Data samples were collected from vegetation in the surrounding areas and analyzed for radioactivity. High energy levels (up to 4-5 times higher than recommended standards, (UNCEAR, 1982) were found in several samples containing (226)Ra, (232)Th, (234)Th, (40)K and (238)U. The study concludes that air quality and vegetation of the neighbouring areas is adversely affected by industrial waste. Greater pollution controls and air quality monitoring should be applied for the benefit and health of its citizens. Radioactivity in food and water and inhaled air become very dangerous for public health thus, the levels of radioactivity should be kept within UNCEAR 1982 limits. PMID:24798903

  1. RADIOACTIVITY DOSAGE OF ORNAMENTAL GRANITIC ROCKS BASED ON CHEMICAL, MINERALOGICAL AND LITHOLOGICAL DATA

    SciTech Connect

    Salas, H.T.; Nalini, H.A. Jr.; Mendes, J.C.

    2004-10-03

    One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite and zircon. Chemical analysis revealed concentrations of uranium of {le} 30ppm, and thorium {le} 130ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for floor tiles in a standard room for samples with total concentration of uranium and thorium greater than 60ppm. On the basis of calculations of {sup 232}Th, {sup 40}K and {sup 226}Ra from Th, K and U analysis, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.

  2. Radioactivity dosage evaluation of Brazilian ornamental granitic rocks based on chemical data, with mineralogical and lithological characterization

    NASA Astrophysics Data System (ADS)

    Salas, Humberto Terrazas; Nalini, Hermínio Arias; Mendes, Júlio César

    2006-02-01

    One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry, and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite, and zircon. Chemical analysis revealed uranium concentrations ≤30 ppm and thorium ≤130 ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for samples, of floor tiles in a standard room, with total concentration of uranium and thorium greater than 60 ppm. On the basis of calculations of 232 Th, 40 K, and 226 Ra from analysis of Th, K, and U, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.

  3. Environmental impact of natural radionuclides from a coal-fired power plant in Spain.

    PubMed

    Charro, Elena; Peña, Víctor

    2013-01-01

    This paper is a study of the radiological impact of a coal-fired power plant in Spain. Activity concentrations of six natural radionuclides were determined in coal, ash, mine wastes and sediments by gamma-ray spectrometry. The average activity concentrations of (238)U, (226)Ra, (224)Ra, (210)Pb, (232)Th and (40)K in coal were 24, 30, 28, 41, 23 and 242 Bq kg(-1)  and in ash were 103, 128, 101, 124, 88 and 860 Bq kg(-1), respectively. The enrichment factor, radium equivalent activity and alpha index in the ash sample have been estimated. For the five waste pile samples, the absorbed dose rate was higher than the world average dose rate (60 nGy h(-1)). The dependence of radionuclide concentration on the grain size of nine sediments was also studied. The analysis of the radionuclides in waste and sediment samples will demonstrate the distribution and mobility of these elements through the environment, where a potential risk of contamination can be detected. PMID:22807496

  4. Natural radioactivity in reservoir sediment near an industrial park of northwest China.

    PubMed

    Lu, Xinwei; Pan, Huiyun; Ren, Chunhui; Yang, Linna

    2016-06-01

    The activity concentration of natural radionuclides in the sediment of a reservoir near an industrial park of northwest China was determined using gamma ray spectrometry. The activity concentrations of (226)Ra, (232)Th and (40)K in the investigated samples range from 30.2 to 37.5, 56.5 to 79.8 and 785.6 to 940.3 Bq kg(-1) with an average of 33.2, 71.8 and 866.2 Bq kg(-1), respectively, which are higher than the corresponding activity concentrations in the control sample. Radium equivalent activity, external hazard index, internal hazard index, indoor air absorbed dose rate and annual effective dose rate were calculated to assess the radiation hazards associated with the use of this sediment in the construction of dwellings. It was concluded that the radiation levels in the reservoir sediment do not give rise to radiological health concerns and the sediment can be safely used in the construction of buildings. PMID:27122204

  5. Environmental radioactivity measurements and applications - Difficulties, current status and future trends

    NASA Astrophysics Data System (ADS)

    Anagnostakis, Marios J.

    2015-11-01

    For several decades natural and artificial radioactivity in the environment have been extensively studied all around the world. Nuclear accidents - mainly that of Chernobyl - have led to the development of the field of radioecology, while detector systems and techniques - with predominant that of γ-spectrometry - have been continuously developed through the years to meet researchers' needs. The study of natural radionuclides that was originally limited to 226Ra, 232Th and 40K was then extended to include radionuclides such as 234Th, 210Pb, 235U and 7Be, which allowed the study of radioactive equilibrium. Besides their importance from the radiation protection point of view, many radionuclides are also used as tracers of environmental processes, such as aerosol and transportation of air masses studies (7Be, 10Be, 22Na), soil erosion, sedimentation and geochronology (210Pb, 137Cs), marine ecosystems studies and studies related to climate change. All these studies require specialized samplings strategies and sampling preparation techniques as well as high quality measurements, while the improvement of detection limits is often of vital importance. This work is a review of environmental radioactivity measurements and applications, mainly focused in the field of γ-spectrometry, for which difficulties and limitations will be presented, together with future trends, new challenges and applications.

  6. Hazard of NORM from phosphorite of Pakistan.

    PubMed

    Sabiha-Javied; Tufail, M; Asghar, M

    2010-04-15

    In order to investigate the radiological hazard of naturally occurring radioactive material (NORM) in phosphorite deposits of Pakistan, 26 samples of phosphorite were collected from the phosphorite mines near Abbottabad, and 20 samples of single superphosphate (SSP) fertilizer were obtained from the warehouses in Pakistan. Activity concentration in all the samples was assayed using HPGe detection system. Specific activity values of (238)U, (40)K, (226)Ra and (232)Th in the samples of phosphorite were 550+/-156 (329-845), 206+/-72 (93-362), 511+/-189 (316-830) and 52+/-17 (23-81) Bq kg(-1), respectively; and those in SSP fertilizer due to these radionuclides were 637+/-44 (596-687), 164+/-24 (113-215), 589+/-44 (521-671) and 29+/-6 (16-45) Bq kg(-1), respectively. The results were compared with that of worldwide soil. Outdoor external dose rate due to gamma rays from phosphorite was calculated to be 276+/-94 (177-441) nGy h(-1) and external dose rate in a room made of phosphorite containing material was estimated to be 706+/-243 (455-1129) nGy h(-1). The concentration of radon was measured in phosphorite mines and in the warehouses for SSP fertilizer by an active method. Protective measures have been proposed to control the pollution in the phosphorite mining and processing, and fertilizer storage areas. PMID:19963319

  7. A study of environmental radioactivity measurements in the Samsun province, Turkey.

    PubMed

    Kucukomeroglu, B; Maksutoglu, F; Damla, N; Cevik, U; Celebi, N

    2012-12-01

    This study was concerned with the measurement of natural and artificial radionuclides in soil samples and indoor radon concentrations in the Samsun province, Turkey. In soil samples, the values of individual mean activity of (226)Ra, (232)Th, (40)K and (137)Cs radionuclides were found to be 31, 22, 341 and 16 Bq kg(-1), respectively. The radiological parameters, such as the absorbed dose rate in air, the annual effective dose (AED) and excess lifetime cancer risk, were calculated. Indoor radon measurements were carried out with CR-39-based radon dosemeters at 127 dwellings in the Samsun province. The mean annual (222)Rn activity was found to be 106 Bq m(-3) (equivalent to an AED of 1.88 mSv). The seasonal variation of (222)Rn activity shows that maximum levels are observed in the winter, while minimum levels are observed in the summer. The mean lifetime fatality risk for the studied area was estimated at 1.45×10(-4). The results obtained did not significantly differ from those obtained in other parts of the country. PMID:22619352

  8. Radon survey and soil gamma doses in primary schools of Batman, Turkey.

    PubMed

    Damla, Nevzat; Aldemir, Kamuran

    2014-06-01

    A survey was conducted to evaluate levels of indoor radon and gamma doses in 42 primary schools located in Batman, southeastern Anatolia, Turkey. Indoor radon measurements were carried out using CR-39 solid-state nuclear track detector-based radon dosimeters. The overall mean annual (222)Rn activity in the surveyed area was found to be 49 Bq m(-3) (equivalent to an annual effective dose of 0.25 mSv). However, in one of the districts (Besiri) the maximum radon value turned out to be 307 Bq m(-3). The estimated annual effective doses are less than the recommended action level (3-10 mSv). It is found that the radon concentration decreases with increasing floor number. The concentrations of natural and artificial radioisotopes were determined using gamma-ray spectroscopy for soil samples collected in close vicinity of the studied schools. The mean gamma activity concentrations in the soil samples were 31, 25, 329 and 12 Bq kg(-1) for (226)Ra, (232)Th, (40)K and (137)Cs, respectively. The radiological parameters such as the absorbed dose rate in air and the annual effective dose equivalent were calculated. These radiological parameters were evaluated and compared with the internationally recommended values. PMID:24437644

  9. [Biological cycle of radionuclides and dynamics of cattle leukemia in the Orenburg region].

    PubMed

    Ponomareva, I S

    2008-01-01

    Global technogenic radionuclides pollution of environment, migration of radionuclides from soil into animal feeds stimulate additional contamination doses. Concentration of natural and of technogenic radionuclides in the investigated objects was determined as result of radiochemical and radiometric studies. It was established that maximum concentrations of 40K, 232Th, 226Ra (Bk/kg) radionuclides in the soil of the eastern zone was 391.6 +/- 77.64; 20.8 +/- 0.71; 16.7 +/- 0.8 (respectively) without exceeding permissable levels. It is also found that the density of soil pollution with 137Cs in the western zone is 0.28 +/- 0.075 mBk/m2 (76.8 +/- 20.4 mKi/km2), such soils are to be considered as locally polluted soils. The number of cattle infected with cattle leucosis is obviously higher in ecologically unsafe areas: 19.3% on the western farms, 12.95% in the central areas and 9.70% on the farms of the eastern zone. Long-term exposure to ecologically unsafe conditions may lead to the reduction of populations immune status expressed in lower disease resistance and in incidence of carcinogenic pathology. PMID:19004334

  10. Naturally occurring radioactive materials (NORMs) generated from lignite-fired power plants in Kosovo.

    PubMed

    Hasani, F; Shala, F; Xhixha, G; Xhixha, M K; Hodolli, G; Kadiri, S; Bylyku, E; Cfarku, F

    2014-12-01

    The energy production in Kosovo depends primarily on lignite-fired power plants. During coal combustion, huge amounts of fly ash and bottom ash are generated, which may result in enriched natural radionuclides; therefore, these radionuclides need to be investigated to identify the possible processes that may lead to the radiological exposure of workers and the local population. Lignite samples and NORMs of fly ash and bottom ash generated in lignite-fired power plants in Kosovo are analyzed using a gamma-ray spectrometry method for the activity concentration of natural radionuclides. The average activity concentrations of (40)K, (226)Ra and (232)Th in lignite are found to be 36 ± 8 Bq kg(-1), 9 ± 1 Bq kg(-1) and 9 ± 3 Bq kg(-1), respectively. Indications on the occurrence and geochemical behavior of uranium in the lignite matrix are suggested. The activity concentrations of natural radionuclides in fly ash and bottom ash samples are found to be concentrated from 3 to 5 times that of the feeding lignite. The external gamma-ray absorbed dose rate and the activity concentration index are calculated to assess the radiological hazard arising from ash disposal and recycling in the cement industry. PMID:25233215

  11. Assessments of natural radioactivity and determination of heavy metals in soil around industrial dumpsites in Sango-Ota, Ogun state, Nigeria

    PubMed Central

    Ademola, Augustine Kolapo; Ayo, Isreal; Babalola; Folasade, Oluwakemi; Alabi; Onyinye, Dorcas; Onuh; Emmanuel, Enifome; Enyenihi

    2014-01-01

    The activity concentration of natural radionuclides in soil samples from industrial dumpsites in Sango-Ota were determined using gamma-ray spectrometry with NaI(Tl) detector. The mean activity concentration of 226Ra, 232Th and 40K was 3.0 ± 1.2, 33.3 ± 9.8 and 122.1 ± 20.6 Bqkg−1, respectively. Radium equivalent activities were calculated to assess the hazards arising from the use of the soil sample in agriculture. All the calculated values were lower than the world average. The mean concentration of heavy metals in the soil samples were 33.6, 2.9, 3.8, 2.7, 48.9, 1,5, 34.5 and 0.8 mg l-1 for Cu, Mg, Ca, P, Fe, Pb, Zn and Cd, respectively. The concentrations of Cd, Cu and Pb were higher than the natural permissible range in soil. Therefore, the government should discourage the use of the soil around dumpsites for planting because of the presence of heavy metals in the sites. PMID:24872608

  12. ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides enhancement rate and dose assessment for residues of lignite-fired thermal power plants in Turkey.

    PubMed

    Parmaksiz, A; Arikan, P; Vural, M; Yeltepe, E; Tükenmez, I

    2011-11-01

    A total of 77 coal, slag and fly ash samples collected from six thermal power plants were measured by gamma-ray spectrometry. The average (226)Ra activity concentrations in coal, slag and fly ash were measured as 199.8±16.7, 380.3±21.8 and 431.5±29.0 Bq kg(-1), respectively. The average (232)Th activity concentrations in coal, slag and fly ash were measured as 32.0±2.4, 74.0±9.0 and 87.3±9.8 Bq kg(-1), respectively. The average (40)K activity concentrations in coal, slag and fly ash were found to be 152.8±12.1, 401.3±25.0 and 439.0±30.2 Bq kg(-1), respectively. The radium equivalent activities of samples varied from 147.6±8.5 to 1077.4±53.3 Bq kg(-1). The gamma and alpha index of one thermal power plant's fly ash were calculated to be 3.5 and 5 times higher than that of the reference values. The gamma absorbed dose rates were found to be higher than that of the average Earth's crust. The annual effective dose of residues measured in four thermal power plants were calculated higher than that of the permitted dose rate for public, i.e. 1 mSv y(-1). PMID:21217134

  13. Radionuclide emissions from a coal-fired power plant.

    PubMed

    Amin, Y M; Khandaker, Mayeen Uddin; Shyen, A K S; Mahat, R H; Nor, R M; Bradley, D A

    2013-10-01

    Current study concerns measurement of radioactivity levels in areas surrounding a 2420 MW thermal power plant fueled predominantly by bituminous coal. The concentrations of (226)Ra, (232)Th and (40)K in onsite bottom-ash were found to be 139 Bq/kg, 108 Bq/kg and 291 Bq/kg, respectively, the levels for these radiolnuclides in soil decreasing with distance from the power plant. At the plant perimeter the respective radionuclide concentrations were 87 Bq/kg, 74 Bq/kg and 297 Bq/kg. In a nearby town, the corresponding concentrations were 104 Bq/kg, 52 Bq/kg and 358 Bq/kg, suggestive of use of TENORM affected soils. The mean radium equivalent activities (Raeq) in soil and ash sample in the town were 205 Bq/kg and 316 Bq/kg, respectively. The Kapar plant ash/slag appears to contain a higher level of TENORM than the world average. The degree of contamination is much higher inside the town where slag has been mixed with topsoil as landfill or as simple domestic waste. For the prevailing levels of exposure and a worst case senario, the predicted committed effective dose due to ingestion and inhalation for intake durations of 1- and 30 years would be 4.2 μSv and 220 μSv, respectively. PMID:23891979

  14. Activity measurements of radon from construction materials.

    PubMed

    Fior, L; Nicolosi Corrêa, J; Paschuk, S A; Denyak, V V; Schelin, H R; Soreanu Pecequilo, B R; Kappke, J

    2012-07-01

    This work presents the results of radon concentration measurements of construction materials used in the Brazilian industry, such as clay (red) bricks and concrete blocks. The measurements focused on the detection of indoor radon activity during different construction stages and the analysis of radionuclides present in the construction materials. For this purpose, sealed chambers with internal dimensions of approximately 60×60×60 cm3 were built within a protected and isolated laboratory environment, and stable air humidity and temperature levels were maintained. These chambers were also used for radon emanation reduction tests. The chambers were built in four major stages: (1) assembly of the walls using clay (red) bricks, concrete blocks, and mortar; (2) installation of plaster; (3) finishing of wall surface using lime; and (4) insulation of wall surface and finishing using paint. Radon measurements were performed using polycarbonate etched track detectors. By comparing the three layers applied to the masonry walls, it was concluded that only the last step (wall painting using acrylic varnish) reduced the radon emanation, by a factor of approximately 2. Samples of the construction materials (clay bricks and concrete blocks) were ground, homogenized, and subjected to gamma-ray spectrometry analysis to evaluate the activity concentrations of 226Ra, 232Th and 40K. The values for the index of the activity concentration (I), radium equivalent activity (Raeq), and external hazard index (Hext) showed that these construction materials could be used without restrictions or concern about the equivalent dose limit (1 mSv/year). PMID:22280793

  15. Assessment of the radiological impact of oil refining industry.

    PubMed

    Bakr, W F

    2010-03-01

    The field of radiation protection and corresponding national and international regulations has evolved to ensure safety in the use of radioactive materials. Oil and gas production processing operations have been known to cause naturally occurring radioactive materials (NORMs) to accumulate at elevated concentrations as by-product waste streams. A comprehensive radiological study on the oil refining industry in Egypt was carried out to assess the radiological impact of this industry on the workers. Scales, sludge, water and crude oil samples were collected at each stage of the refining process. The activity concentration of (226)Ra, (232)Th and (40)K were determined using high-resolution gamma spectrometry. The average activity concentrations of the determined isotopes are lower than the IAEA exempt activity levels for NORM isotopes. Different exposure scenarios were studied. The average annual effective dose for workers due to direct exposure to gamma radiation and dust inhalation found to be 0.6 microSv and 3.2 mSv, respectively. Based on the ALARA principle, the results indicate that special care must be taken during cleaning operations in order to reduce the personnel's exposure due to maintenance as well as to avoid contamination of the environment. PMID:20005611

  16. Gamma spectroscopic analysis and associated radiation hazards of building materials used in Egypt.

    PubMed

    El-Taher, A

    2010-02-01

    Radiation exposure of the population can be increased appreciably by the use of building materials containing above-normal levels of naturally occurring radionuclides of terrestrial origin. Using gamma-ray spectrometry, the natural radioactivity levels of 55 samples of natural and manufactured Egyptian building materials have been investigated. The samples were collected from local market and construction sites. From the measured gamma-ray spectra, activity concentrations were determined. The activities were in the ranges 11.7-35.6, 12.4-55.2 and 60-350 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The activities are compared with available reported data from other countries and with the world average value for soils. The radium equivalent activity Ra(eq), the external hazard index H(ex) and the absorbed dose rate in air D in each sample was evaluated to assess the radiation hazard for people living in dwellings made of the materials studied. All building materials have shown Ra(eq) (range from 37.76 to 116.87 Bq kg(-1)) lower than the limit of 370 Bq kg(-1) adopted by the Organization for Economic Cooperation and Development (OECD). The absorbed dose rate in indoor air is lower than the international recommended value of 55 nGy h(-1) for all test samples. All the materials examined are acceptable for use as building materials as defined by the OECD criterion. PMID:19841012

  17. Natural and anthropogenic radioactivity in the environment of Kopaonik mountain, Serbia.

    PubMed

    Mitrović, Branislava; Ajtić, Jelena; Lazić, Marko; Andrić, Velibor; Krstić, Nikola; Vranješ, Borjana; Vićentijević, Mihajlo

    2016-08-01

    To evaluate the state of the environment in Kopaonik, a mountain in Serbia, the activity concentrations of (4) K, (226)Ra, (232)Th and (137)Cs in five different types of environmental samples are determined by gamma ray spectrometry, and radiological hazard due to terrestrial radionuclides is calculated. The mean activity concentrations of natural radionuclides in the soil are higher than the global average. However, with an exception of two sampling locations, the external radiation hazard index is below one, implying an insignificant radiation hazard. Apart from (40)K, content of the natural radionuclides is predominantly below minimum detectable activities in grass and cow milk, but not in mosses. Although (137)Cs is present in the soil, grass, mosses and herbal plants, its specific activity in cow milk is below minimum detectable activity. Amongst the investigated herbal plants, Vaccinium myrtillus L. shows accumulating properties, as a high content of (137)Cs is detected therein. Therefore, moderation is advised in consuming Vaccinium myrtillus L. tea. PMID:27213569

  18. Evaluation of the diffuse contamination of soils caused by residues coming from the large scale production of phosphate fertilisers

    NASA Astrophysics Data System (ADS)

    Martinez, M. J.; Perez-Sirvent, C.; Martinez-Lopez, S.; Bolivar, J. P.; Mosqueda, F.; Vaca, F.; Garcia-Tenorio, R.

    2012-04-01

    The obtaining of phosphate fertilizers results in large amounts of residues that are frequently accumulated in deposits or pools occupying a wide area. These residues are acidic, and contain variable amounts of trace elements and radionuclides. The potentially polluting agents can be leached by rainwater, and so transferred to the surface waters and then to the groundwater after soil infiltration. Since the distribution and thickness of the residue deposits are variable, the contaminants cannot be easily traced back to a single, well defined source, and so a diffuse contamination (nonpoint source pollution) of the surrounding soils and waters occurs. This communication reports the results obtained in the study of soils close to the phosphogypsum deposits placed near Rio Tinto (Huelva, Spain). The zone is affected not only by the mentioned residues but also by the tides due to the vicinity of the sea. The samples studied had a low organic content and a low acidity with average values of 30 mS/cm for the EC. The mineralogical study allowed illite, goethite, quartz, gypsum and kaolinite to be identified as the main mineralogical components. Although the arsenic level was relatively high (about 600 mg/Kg) the data proved that this element is not mobilized into water. Analytical data for 238U , 234U, 235U, 228Th, 230Th, 232Th, 226Ra, 228Ra, 210Po, 40K , 137Cs were also obtained.

  19. Natural radioactivity of the tar-sand deposits of Ondo State, Southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Fasasi, M. K.; Oyawale, A. A.; Mokobia, C. E.; Tchokossa, P.; Ajayi, T. R.; Balogun, F. A.

    2003-06-01

    A combination of gamma spectrometry and energy dispersive X-ray fluorescence was used to determine the presence and level of radioactivity of radionuclides in bituminous sand and overburden obtained from bituminous sand deposits in Ondo State Nigeria for the purpose of providing baseline data and assessing its impact on the environment. The radionuclides identified with reliable regularity belong to the decay series of naturally occurring radionuclides headed by 238U and 232Th. The non-decay series of naturally occurring 40K was found to be below the limit of detection. The average specific activity concentration values obtained for 214 Bi, 208Tl, and 226Ra in the overburden are 165.64±2.91, 150.25±2.91 and 60.97±2.27 Bq kg -1, respectively. The measured activity in the bituminous sand layer is so low that it can be said to be non-radioactive. The result of the EDXRF supports the presence of radioelements in the overburden, which are likely to be embedded in accessory minerals like zircon and tourmaline. Thus, surface exploration technique using soil-gas radon measurement will not yield the desired result. Furthermore, the level of radioelements and associated decay daughter 222Rn is not expected to cause any health hazard.

  20. In situ gamma ray measurements of radionuclides at a disused phosphate mine on the West Coast of South Africa.

    PubMed

    Bezuidenhout, Jacques

    2015-12-01

    High levels of uranium and its radioactive progeny like radium is normally associated with phosphate mining. In Situ gamma ray spectroscopy as a survey tool has been successfully applied to assess radionuclide concentrations in various geographical environments. A transportable and robust gamma ray detection system (GISPI) was therefore employed to determine the concentrations of naturally occurring radionuclides at a disused phosphate mine on the West Coast of South Africa. The concentrations of radium, thorium and potassium were measured and plotted. The measurements showed fairly high concentrations with medians of 320 Bq/kg for (226)Ra, 64 Bq/kg for (232)Th and 390 Bq/kg for (40)K. The highest concentrations were however confined to specific areas of the mine. The effective dose due to gamma irradiation for the various areas of the mine was also estimated and the highest estimated level was 0.45 mSv/y. The article finally draws conclusions as to the origins and impact of the radiation. PMID:26254719

  1. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan.

    PubMed

    Al-Kharouf, Samer J; Al-Hamarneh, Ibrahim F; Dababneh, Munir

    2008-07-01

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of (238)U, (235)U, (232)Th, (226)Ra, (222)Rn, (137)Cs and (40)K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y(-1) for (238)U and (234)U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg(-1) and 1, respectively. PMID:18359539

  2. Cryogenic System for Interferometric Measurement of Dimensional Changes at 40 K: Design and Performance

    NASA Technical Reports Server (NTRS)

    Blake, Peter; Miller, Franklin; Zukowski, Tim; Canavan, Edgar R.; Crane, Allen; Madison, Tim; Miller, David

    2007-01-01

    This report describes the facility, experimental methods, characterizations, and uncertainty analysis of the Cryo Distortion Measurement Facility (CDMF) at the Goddard Space Flight Center (GSFC). This facility is designed to measure thermal distortions of structural elements as the temperature is lowered from 320K to below 40 K over multiple cycles, and is capable of unattended running and data logging. The first measurement is to be the change in length and any bending of composite tubes with Invar end-fittings. The CDMF includes a chamber that is efficiently cooled with two cryo-coolers (one single-stage and one two-stage) rather than with liquid cryogens. Five optical ports incorporate sapphire radiation shields - transparent to the interferometer - on each of two shrouds and a fused silica vacuum-port window. The change in length of composite tubes is monitored continuously with displacement-measuring interferometers; and the rotations, bending, and twisting are measured intermittently with theodolites and a surface-figure interferometer. Nickel-coated invar mirrors and attachment mechanisms were developed and qualified by test in the CDMF. The uncertainty in measurement of length change of 0.4 m tubes is currently estimated at 0.9 micrometers.

  3. A 40 kDa protein of the inner membrane is the mitochondrial calcium uniporter

    PubMed Central

    De Stefani, Diego; Raffaello, Anna; Teardo, Enrico; Szabò, Ildikò; Rizzuto, Rosario

    2014-01-01

    Mitochondrial Ca2+ homeostasis plays a key role in the regulation of aerobic metabolism and cell survival1, but the molecular identity of the Ca2+ channel, the mitochondrial calcium uniporter2, was still unknown. We have identified in silico a protein (denominated MCU) that shares tissue distribution with MICU1, a recently characterized uniporter regulator3, coexists with uniporter activity in phylogeny and includes two trasmembrane domains in the sequence. siRNA silencing of MCU in HeLa cells drastically reduced mitochondrial Ca2+ uptake. MCU overexpression doubled the [Ca2+]mt rise evoked by IP3-generating agonists, thus significantly buffering the cytosolic elevation. The purified MCU protein exhibited channel activity in planar lipid bilayers, with electrophysiological properties and inhibitor sensitivity of the uniporter. A mutant MCU, in which two negatively-charged residues of the putative pore forming region were replaced, had no channel activity and reduced agonist-dependent [Ca2+]mt transients when overexpressed in HeLa cells. Overall, these data demonstrate that the identified 40 kDa protein is the channel responsible for Ruthenium Red-sensitive mitochondrial Ca2+ uptake, thus providing molecular basis for this process of utmost physiological and pathological relevance. PMID:21685888

  4. Long Hyperfine Coherence Time of Ultracold Fermionic 23 Na40 K Molecules

    NASA Astrophysics Data System (ADS)

    Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin

    2016-05-01

    Ultracold molecules created and trapped at sub uK temperatures allow the full control of the molecule's external and internal degrees of freedom down to a single hyperfine state. In particular, an ensemble of molecules all initialized in a single rotational and hyperfine state can be prepared and be coherently addressed using microwave fields. In this talk, we report on the observation of long coherence time between two hyperfine states of fermionic 23 Na40 K molecules in the ro-vibronic ground state (v = 0 , J = 0). A direct two-photon microwave transition via the J = 1 state is used to prepare a superposition of two lowest hyperfine states of J = 0 , and we perform Ramsey spectroscopy as a direct probe of phase coherence between these states. The fermionic nature of the molecules and the lack of electronic angular momentum in the ro-vibronic ground state heavily suppress the decoherence from collisions and external fields, respectively, and we observe long coherence times upto 0.5 sec for this hyperfine superposition state. The observed long coherence time is a crucial step for applications of trapped dipolar molecules in quantum information processing schemes.

  5. Studies on radionuclides 228Ra, 238U, 228Th and 40K in selected seaweeds of coastal Tamil Nadu, India.

    PubMed

    Saroja, P Mary; Immanuel, G; Raj, G Allen Gnana; Selvan, K Esai

    2012-09-01

    Studies on natural and anthropogenic radioactivity assume greater importance in the context of human health and development. Hence two species of seaweeds viz: Gracilaria edulis and Ulva lactuca, from three high background radiation areas (Arockiapuram, Kadiapattinam and Kurumpanai) on the southwest coast of Tamil Nadu, and Mandapam as low background radiation area of the southeast coast of Tamil Nadu were studied for variations in activity concentration of 228Ra, 40K, 238U and 228Th. Among these radionuclides, 40K recorded significant inter-species variation while 238 U and 228Th showed significant association. The overall mean concentration of radionuclides was found high in G. edulis (5.31,57.49,36.05,356.55 Bq kg(-1) for 228Ra, 40K, 238U, 228Th respectively), while the mean concentrations for U. lactuca were 4.88, 42.35, 34.40,347.70 Bqkg(-1) for 228Ra, 40K, 238U, 228Th respectively. The mean concentration of radionuclides was uniformly found low during northeast monsoon season in both the seaweed species. PMID:23734458

  6. A thalium-doped sodium iodide well counter for radioactive tracer applications with naturally-abundant 40K

    NASA Astrophysics Data System (ADS)

    Parker, Andrew J.; Boxall, Colin; Joyce, Malcolm J.; Schotanus, Paul

    2013-09-01

    The use of a thallium-doped sodium-iodide well-type scintillation detector for the assay of the low-activity radioisotope 40K, in open-source potassium chloride aqueous solutions, is described. The hazards, safety concerns and radiowaste generation associated with using open-source radioactive isotopes can present significant difficulties, the use of hot cells and escalated costs in radioanalytical laboratory research. A solution to this is the use of low-hazard alternatives that mimic the migration and dispersion characteristics of notable fission products (in this case 137Cs). The use of NaI(Tl) as a detection medium for naturally-abundant levels of 40K in a range of media is widespread, but the use of 40K as a radioactive tracer has not been reported. The use of such low-activity sources is often complicated by the ability to detect them efficiently. In this paper a scintillator detector designed to detect the naturally-abundant 40K present in potassium chloride in tracer applications is described. Examples of the use of potassium chloride as a tracer are given in the context of ion exchange and electrochemical migration studies, and comparisons in performance are drawn from literature with hyper pure germanium semiconductor detectors, which are more commonly utilised detectors in high-resolution counting applications.

  7. Investigation of natural radioactivity levels in water around Kadugli, Sudan.

    PubMed

    Osman, Alfatih A A; Salih, Isam; Shaddad, Ibrahim A; El Din, Saif; Siddeeg, M B; Eltayeb, Hatem; Idriss, Hajo; Hamza, Walid; Yousif, E H

    2008-11-01

    Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for (238)U, (226)Ra, (222)Rn, and (232)Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: <1.0-7.5, 8.5-16.5, <1.6, and <0.1-0.39 mBq L(-1) for (238)U, (226)Ra, (222)Rn, and (232)Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, <0.1-39 mBq L(-1)) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr(-1) except in one groundwater sample with an associated dose of 0.7 mSv yr(-1). PMID:18513978

  8. Giant Anharmonicity and Theory of Surprising BCS Superconductivity in MgB2 at 40 K

    NASA Astrophysics Data System (ADS)

    Yildirim, Taner

    2002-03-01

    The recent surprise discovery of superconductivity in MgB2 at 40 K has stimulated a great deal of research on this intercalated grahite-like system. Sparked by this discovery, we set out to unlock the structural secrets and, in particular, to reveal the origin of the high Tc in MgB_2; an electron-phonon or other exotic mechanism? To answer this fundamental question, we calculated T_c, its pressure dependence for uni- and biaxial compressions, and the isotope effect from the electronic band structure and lattice dynamics of MgB2 using density functional theory[1-2]. The calculated phonon density of states (DOS) are in excellent agreement with the inelastic neutron scattering measurements. We find that the in-plane boron phonons near the zone-center are very anharmonic and strongly coupled to the planar B sigma bands near the Fermi level. The boron mass and pressure dependence of this mode is found to be the key to quantitatively explaining the observed high T_c, the total isotope effect, and the pressure dependence of T_c. We propose that a stringent test on the hole and phonon based theories of the superconductivity in MgB2 would be a measurement of the biaxial ab-compression dependence of T_c. In collobration with Oguz Gulseren, NIST and UPENN [1] T. Yildirim et. al., Phys. Rev. Lett. 87, 037001 (2001). [2] For details, see http://www.ncnr.nist.gov/staff/taner/mgb2

  9. Influence of entrance channel on the production of hassium isotopes

    NASA Astrophysics Data System (ADS)

    Hong, Juhee; Adamian, G. G.; Antonenko, N. V.

    2015-07-01

    The production of hassium isotopes Hs-271266 in various reactions 22Ne+249Cf,Mg,2625+248Cm,30Si+244Pu,S,3634+238U,40Ar+232Th , and 48Ca+226Ra is studied within the dinuclear system model. The experimental excitation functions of the isotopes 266 -271Hs are well described and predictions are made for future experiments.

  10. Naturally occurring radioactive material from the aluminium industry--a case study: the Egyptian Aluminium Company, Nag Hammady, Egypt.

    PubMed

    Abbady, Adel G E; El-Arabi, A M

    2006-12-01

    The activity concentrations and the gamma-absorbed dose rates of the terrestrial naturally occurring radionuclides (226)Ra and (232)Th were determined in samples of bauxite, alumina and aluminium dross tailings industrial waste (used to produce two types of alums) using high purity germanium (HPGe) gamma ray spectrometry. The bauxite and alumina are imported by Egyptalum (The Egyptian Aluminium Company, Nag Hammady, Egypt) from Guinea and India. The activity concentrations in the bauxite range from 29 +/- 1 to 112 +/- 6 Bq kg(-1) for (226)Ra, and 151 +/- 8 to 525 +/- 12 Bq kg(-1) for (232)Th, with mean values of 62 +/- 8 and 378 +/- 50 Bq kg(-1), respectively. With respect to alumina and tail, the mean values are 5.7 +/- 1.1 and 8.4 +/- 0.8 Bq kg(-1) for (226)Ra and 7.2 +/- 1.6 and 10.7 +/- 1.2 Bq kg(-1) for (232)Th. Potassium-40 was not detected in any of the studied samples. The measured activity concentrations of (226)Ra and (232)Th in bauxite are higher than the world average while in alumina and tail they are lower. As a measure of radiation hazard to the occupational workers and members of the public, the Ra equivalent activities and external gamma dose rates due to natural radionuclides at 1 m above the ground surface were calculated. The external gamma-radiation doses received by the Egyptalum workers are 97, 409, 8.5 and 12.7 microSv y(-1) for the Guinean and Indian bauxite, the alumina and tail, respectively, which is well below the recommended allowed dose of 1 mSv y(-1) for non-exposed workers. PMID:17146126

  11. 40K-40Ca systematics as a tracer of silicate weathering in the Himalayas

    NASA Astrophysics Data System (ADS)

    Davenport, J.; Caro, G.; France-Lanord, C.

    2015-12-01

    Increased weathering resulting from the uplift of the Himalayan Mountains has been cited as one cause (among others) of late Cenozoic cooling. Orogenic uplift generally results in the development of high relief and enhanced erosion, which in turn induces rapid chemical weathering and uptake of atmospheric CO2. Tracing these processes can be accomplished using techniques such as the budget of major element and/or Sr isotopes of the dissolved load. However, in the Himalaya, Sr isotopic compositions are extreme even in carbonate phases, making it difficult to produce realistic estimates of silicate and carbonate inputs to Himalayan rivers. In this study, we explore the potential of the 40K-40Ca system to quantify the relative contributions of silicate and carbonate weathering to river dissolved loads. To this end, we analysed a suite of 40 rivers draining the main litho-tectonic units of the Himalaya, sediments, bedrock, mineral separates and soil and gravel. Our results show that Himalayan carbonates exhibit no radiogenic 40Ca excess despite highly variable 87Sr/86Sr signatures (0.73-0.85). The silicate fraction of bedload sediments is variably radiogenic (+1 to +4), with ɛ40Ca correlating with the 87Sr/86Sr ratio. Analyses of plagioclase, biotite and muscovite separates from a HHC gneiss and greywacke show homogeneous ɛ40Ca despite highly variable K/Ca ratios, indicating recent metamorphic equilibration on a mineral scale. Thus, incongruent weathering of high K/Ca minerals should not represent a significant factor when considering the transfer of radiogenic calcium to the dissolved load. The ɛ40Ca signatures of dissolved river material are significantly influenced by silicate lithologies, and range from +0.1 in carbonate dominated catchments to >+2 ɛ-units in rivers draining predominantly silicate catchments. The silicate contributions estimated from our 40Ca results are in line with major element budgets when considering small catchments but largely exceeds

  12. 40K-40Ca and 87Rb-86Sr Dating by SIMS: The Double-Plus Advantage

    NASA Astrophysics Data System (ADS)

    Harrison, T. M.; McKeegan, K. D.; Schmitt, A. K.

    2009-12-01

    The decay of 40K to 40Ar forms the basis of the potassium-argon dating method, although only one out of every 10 parent atoms decays to daughter 40Ar. The other 90% decay to 40Ca giving, in principle, the 40K-40Ca decay system great potential for dating samples with high K/Ca. This method, however, has not been utilized as an ion-microprobe-based geochronometer, largely because these isotopes require a very high mass resolving power (MRP) of ~25k for full separation. We found that limiting secondary ion transmission in our ims1270 ion microprobe to ~20% permits sufficient separation of 40K from 40Ca (MRP≈ 20k) to permit isotope ratio analysis, albeit with 40Ca+ on the shoulder of the more intense 40K+ peak. A pegmatitic muscovite from Jack Hills (K-Ca age = 2.54 Ga; Fletcher et al., Chem. Geol. 138, 289) yields ~104 cps of both 40K+ and 40Ca+ with a 15 μm primary spot size and O- beam current of 10 nA. The 40Ca+ signal is >90% radiogenic and reflects a “common” Ca content of ≤ 100 ppm. However, application of the relative sensitivity factor (RSF) calculated from the Jack Hills muscovite to unknowns yields relatively high age dispersion, perhaps related to the incompletely separated mass interferences. Theorizing that the noble gas electronic structure of K+ would likely resist further electron loss, we investigated an alternative approach involving analysis of Ca++/K++. The double-plus method provides an important advantage in that K++ species are suppressed by a factor of ~103 relative to K+, thereby effectively removing 40K++ from the spectrum at m/e≈ 20 and leaving 40Ca++ free from any significant interferences at an MRP≈ 4k. Measurement of the much more abundant 39K++ then permits 40Ca++/40K++ to be calculated from the known 39K/40K ratio. We applied this approach to Precambrian muscovite samples obtaining ages similar to, but generally younger than, their associated 40Ar/39Ar ages. This could reflect a minor matrix effect or a lower intrinsic

  13. Analysis of Potassium in Bricks--Determining the Dose Rate from {sup 40}K for Thermoluminescence Dating

    SciTech Connect

    Musilek, Ladislav; Polach, Tomas; Trojek, Tomas

    2008-08-07

    Thermoluminescence (TL) dating is based on accumulating the natural radiation dose in the material of a dated artefact (brick, pottery, etc.), and comparing the dose accumulated during the lifetime of the object with the dose rate within the sample collected for TL measurement. Determining the dose rate from natural radionuclides in materials is one of the most important and most difficult parts of the technique. The most important radionuclides present are usually nuclides of the uranium and thorium decay series and {sup 40}K. An analysis of the total potassium concentration enables us to determine the {sup 40}K content effectively, and from this it is possible to calculate the dose rate originating from this radiation source. X-ray fluorescence (XRF) analysis can be used to determine the potassium concentration in bricks rapidly and efficiently. The procedure for analysing potassium, examples of results of dose rate calculation and possible sources of error are described here.

  14. Estimating adipose tissue in the chest wall using ultrasonic and alternate /sup 40/K and biometric measurements

    SciTech Connect

    Anderson, A.L.; Campbell, G.W.

    1982-01-22

    The percentage of adipose (fat) tissue in the chest wall must be known to accurately measure Pu in the human lung. Correction factors of 100% or more in x-ray detection efficiency are common. Methods using simple /sup 40/K and biometric measurement techniques were investigated to determine the adipose content in the human chest wall. These methods predict adipose content to within 15% of the absolute ultrasonic value. These new methods are discussed and compared with conventional ultrasonic measurement techniques. (ERB)

  15. Analytical evaluation of natural radionuclides and their radioactive equilibrium in raw materials and by-products.

    PubMed

    Ji, Young-Yong; Chung, Kun Ho; Lim, Jong-Myoung; Kim, Chang-Jong; Jang, Mee; Kang, Mun Ja; Park, Sang Tae

    2015-03-01

    An investigation into the distribution of natural radionuclides and radioactive secular equilibrium in raw materials and by-products in a domestic distribution was conducted to deduce the optimum conditions for the analytical evaluation of natural radionuclides for (238)U, (226)Ra, and (232)Th using a gamma-ray spectrometer and inductively coupled plasma mass spectrometer (ICP-MS). The range of the specific activities of natural radionuclides was first evaluated by analyzing (228)Ac and (214)Bi, which are (232)Th and (226)Ra indicators, respectively, in about 100 samples of raw materials and by-products through a gamma-ray spectrometer. From further experiments using several samples selected based on the results of the distribution of natural radionuclides, the validation of their analytical evaluations for the indirect measurements using a gamma-ray spectrometer and direct measurements using ICP-MS was assured by comparing their results. Chemically processed products from the raw materials, such as Zr sand and ceramic balls, were generally shown for the type of bead and particularly analyzed showing a definite disequilibrium with above a 50% difference between (238)U and (226)Ra in the uranium series and (232)Th and (228)Ra in the thorium series. PMID:25527894

  16. Determination of potassium in several plants and study of potassium transfer to different beverages, including tequila, by measurement of 40K

    NASA Astrophysics Data System (ADS)

    Navarrete, J. M.; Muller, G.; Cabrera, L.; Martinez, T.

    2006-01-01

    Measurement of 40K was used for determination of potassium concentrations in leaves of agave and maguey cactus leaves, and coffee beans of various origins. The procedure was also used to study potassium transfer to tequila (alcoholic drink made of agave cactus), and the cactus and coffee infusions using 40K as a natural radioactive tracer. Counting of 40K in Marinelli containers with the aid of a low background NaI(Ti) scintillation detection system for 12 24 hours was employed. The method appeared to be simple and suitable for determination of potassium concentrations in large samples, which eliminates homogeneity problems.

  17. Activity size distributions of some naturally occurring radionuclides 7Be, 40K and 212Pb in indoor and outdoor environments.

    PubMed

    Mohamed, A

    2005-05-01

    The activity size distributions of natural radionuclides (7)Be and (40)K were measured outdoor in El-Minia city, Egypt by means of gamma spectroscopy. A low-pressure Berner cascade impactor was used as a sampling device. The activity size distribution of both (7)Be and (40)K was described by one log-normal distribution, which was represented by the accumulation mode. The activity median aerodynamic diameter (AMAD) of (7)Be and (40)K was determined to be 530 and 1550 nm with a relative geometric standard deviation (delta, which was defined as the dispersion of the peak) of 2.4 and 2, respectively. The same sampling device (Berner impactor) and a screen diffusion battery were used to measure the activity size distribution, activity concentration and unattached fraction (f(P)) of (212)Pb in indoor air of El-Minia City, Egypt. The mean activity median aerodynamic diameter (AMAD) of the accumulation mode for attached (212)Pb was determined to be 250 nm with a mean geometric standard deviation (delta) of 2.6. The mean value of the specific concentration of (212)Pb associated with that mode was determined to be 460+/-20 mBq m(-3). The activity median thermodynamic diameter (AMTD) of unattached (212)Pb was determined to be 1.25 nm with delta of 1.4. A mean unattached fraction (f(p)) of 0.13+/-0.02 was obtained at a mean aerosol particle concentration of 1.8 x 10(3) cm(-3). The mean activity concentration of unattached (212)Pb was found to be 19+/-3 mBq m(-3). It was found that the aerosol concentration played an important role in varying the unattached, attached activity concentration and unattached fraction (f(P)). PMID:15763482

  18. Evaluation of radiation hazard potential of TENORM waste from oil and natural gas production.

    PubMed

    Hilal, M A; Attallah, M F; Mohamed, Gehan Y; Fayez-Hassan, M

    2014-10-01

    In this study, a potential radiation hazard from TENORM sludge wastes generated during exploration and extraction processes of oil and gas was evaluated. The activity concentration of natural radionuclides (238)U, (226)Ra and (232)Th were determined in TENORM sludge waste. It was found that sludge waste from oil and gas industry is one of the major sources of (226)Ra in the environment. Therefore, some preliminary chemical treatment of sludge waste using Triton X-100 was also investigated to reduce the radioactivity content as well as the risk of radiation hazard from TENORM wastes. The activity concentrations of (226)Ra and (228)Ra in petroleum sludge materials before and after chemical treatment were measured using gamma-ray spectrometry. The average values of the activity concentrations of (226)Ra and (228)Ra measured in the original samples were found as 8908 Bq kg(-1) and 933 Bq kg(-1), respectively. After chemical treatment of TENORM samples, the average values of the activity concentrations of (226)Ra and (228)Ra measured in the samples were found as 7835 Bq kg(-1) and 574 Bq kg(-1), respectively. Activity concentration index, internal index, absorbed gamma dose rate and the corresponding effective dose rate were estimated for untreated and treated samples. PMID:24949581

  19. Uranium and other natural radionuclides in the sediments of a Mediterranean fjord-like embayment, Amvrakikos Gulf (Ionian Sea), Greece.

    PubMed

    Papaefthymiou, H; Athanasopoulos, D; Papatheodorou, G; Iatrou, M; Geraga, M; Christodoulou, D; Kordella, S; Fakiris, E; Tsikouras, B

    2013-08-01

    The distribution of the natural radionuclides ((238)U, (232)Th, (226)Ra, (40)K) and the artificial (137)Cs was studied in sediment cores collected from Amvrakikos Gulf, a seasonal anoxic marine basin, using γ-ray spectrometry. The activity of radionuclides, along with the concentrations of Fe and Mn, were also studied in relation to the total organic carbon and the granulometric fractions of the sediments. The results obtained revealed higher (238)U activity concentrations in all the examined sediment samples compared to the world and Greek average values for soil. The high activity values of (238)U are attributed, besides the lattice-held fraction, to phosphate fertilizer inputs in the Gulf via major rivers and/or to alteration processes of phosphate ores located mainly in the drainage basin of the river Louros. The elevated activity values of (40)K could be attributed to the mineralogical composition of the sediments and to phosphate fertilizers containing potassium. Organic matter seems to be a more efficient sorbent for U than clay minerals and amorphous Fe and Mn-oxyhydroxides. Scanning electron microscopy, together with qualitative analysis of some smectites, reveals the occurrence of U, suggesting a limited absorption of U onto clay minerals. The applied BCR sequential extraction procedure revealed that U was found mainly in the refractory phase or associated with organic matter and to a lesser extent as surface-coating oxides, with the exception of one sediment core which is characterized by high content of fresh marine organic matter and presents high percentage of U in the exchangeable fraction. PMID:23538023

  20. Level of natural and artificial radioactivity in Algeria.

    PubMed

    Baggoura, B; Noureddine, A; Benkrid, M

    1998-07-01

    A national environmental sampling program was carried out during 1993 to determine natural and artificial radionuclides contents in the (0-15 cm) upper layer of the soil. The main objective was to establish a radioactive reference level in the whole territory, since 131I, 134Cs and 137Cs were detected in most of the analysed samples collected right after the Chernobyl accident (May 1986). Soil samples were analysed by direct counting by gamma-ray spectrometry. In addition, terrestrial gamma-ray dose rates in air have been measured out of doors throughout Algeria. In each of the 48 administrative divisions of the country selected sites were chosen to collect soil samples and measure gamma-ray dose rates. The gamma-emitting radionuclides resulting from the radioactive decay of 238U and 232Th, 40K and 137Cs were detected in most of the analysed samples. Radioactivity concentrations in Bq kg-1 dry mass in soil samples of 226Ra, 214Pb, 214Bi, 212Pb, 228Ac, 40K and 137Cs range between (5-176), (2-107), (3-65), (2-97), (3-144), (36-1405) and (0.3-41) respectively. In addition, six selected soil samples were analysed to determine plutonium isotopes contents. Radioactivity concentrations in Bq kg-1 dry mass of 238Pu and 239 + 240Pu vary between (0.012-0.013) and (0.24-0.61) respectively. The dose rates in air measured over the whole country were found to range between 20 and 133 nGy h-1. Presence of 137Cs has been clearly observed. An approach has been made to determine its origin, considering the global fallout, the Chernobyl accident and the French nuclear bomb tests in the 60s as the main potential sources. It is concluded that Algeria has indeed been affected by the Chernobyl accident. PMID:9570102

  1. Radioactivity in the community water supplies of Ife-Central and Ife-East local government areas of Osun State, Nigeria

    NASA Astrophysics Data System (ADS)

    Tchokossa, P.; Olomo, J. B.; Osibote, O. A.

    1999-02-01

    The average concentrations of radionuclides in the various types of community water supplies of the Ife-Central and Ife-East Local Government areas with a population of 200 000 people were estimated from the measurements of mean specific activity using a well-calibrated Canberra vertical coaxial high-purity germanium detector system. Water samples were collected from dam, streams, boreholes, wells, tap water, etc., being the most frequently used water sources in the study area. The radionuclides observed with reliable regularity belonged to the series - decay naturally occurring radionuclides headed by 238U and 232Th as well as the non-series nuclide, 40K. The average specific activity values obtained for 226Ra, 228Ra and 40K, respectively, were 8.67±4.28, 2.31±1.48 and 98.99±6.23 Bq l -1 for well water; 12.45±3.39, 3.02±0.64 and 97.46±6.35 Bq l -1 for borehole water; 12.41±1.37, 2.47±0.09 and 85.06±17.27 Bq l -1 for tap water; 10.40±1.70, 2.70±1.30 and 72.60±9.10 Bq l -1 for dam water; 7.04±0.66, 3.55±0.13 and 69.18±20.80 Bq l -1 for stream water.

  2. Ra-Th disequilibria systematics: Timescale of carbonatite magma formation at Oldoinyo Lengai volcano, Tanzania

    NASA Astrophysics Data System (ADS)

    Williams, Ross W.; Gill, James B.; Bruland, Kenneth W.

    1986-06-01

    Carbonatite magma can form and erupt within 7 to 18 years, and the event seems associated with prior volcanic eruptions. This determination of magma age is possible because the carbonatite lava and ash which were erupted in 1960-1966 from Oldoinyo Lengai volcano, Tanzania, have the most extreme disequilibria between U and Th series nuclides yet measured in volcanic rocks. At the time of eruption: ( 228Ra) /( 232Th) ≈ 27 and ( 226Ra) /( 230Th) > 60 ; ( 238U) /( 232Th) > 10 , while ( 232Th) /( 232Th) = 1.0 ; and ( 210Pb) /( 226Ra) ≈ 0.3 . Three end-member models are presented which enable interpretation of these disequilibria. If the disequilibrium formed instantaneously, the event occurred about 7 years before initial eruption, and just before the last preceding but small eruption of Oldoinyo Lengai. If, instead, the disequilibrium formed continuously, the process must have begun 15 to 18 years before initial eruption, just after the last preceding major eruption. The disequilibria data confirm that the carbonatites are not fused trona, but do not distinguish between other genetic options (mantle fusion, selective assimilation, liquid immiscibility). However, the shortness of magma-formation time together with mass-balance considerations suggest formation due to the continuous exsolution of 2 to 20% of carbonatite from nephelinite which was itself Ra-enriched.

  3. Peginterferon alfa-2a (40 kDa) monotherapy: a novel agent for chronic hepatitis C therapy.

    PubMed

    Zeuzem, S; Heathcote, J E; Martin, N; Nieforth, K; Modi, M

    2001-12-01

    Current therapy for hepatitis C remains far from optimal. The modification of IFN by the attachment of a polyethylene glycol (PEG) moiety has produced long-lasting IFNs. A 40 kDa branched peginterferon alfa-2a (40 kDa) (PEG-IFN alfa-2a) has unique pharmacokinetic and pharmacodynamic properties. PEG-IFN alfa-2a is absorbed in a sustained manner and its clearance is reduced substantially compared with IFN alfa-2a, resulting in sustained serum drug concentrations. These constant serum drug levels stay above the EC(50) values (effective concentration 50%) needed for antiviral, antiproliferative and immunomodulatory actions. Sustained virological responses were significantly greater in patients who received PEG-IFN alfa-2a versus IFN alfa-2a, with a similar side effect profile. Histological improvements were seen in patients who achieved sustained virological responses and were frequently observed among patients who did not achieve a virological response. The advantages of PEG-IFN alfa-2a were also seen in patients with cirrhosis or hepatitis C virus (HCV) genotype 1. PMID:11772316