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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. [About the contents of 40K, 226Ra and 232Th in forest soils of the Republic of Belarus].

    PubMed

    Perevolotskiĭ, A N; Perevolotskaia, T V

    2014-01-01

    The specific activity of 40K, 232Th and 226Ra in forest soil ecotopes (A2-B2-C2-D2) has been investigated. When the fertility of the soil increases from A2 to D2, then the specific activity of 40K increases in the rooting zone of the soil from 275 ± 6.9 up to 499 ± 11 Bq/kg, 232Th--from 11.8 ± 0.5 to 17.1 ± 1.1 Bq/kg, 226Ra- from 19.2 γ 0.8 to 27.9 ± 1.5 Bq/kg. The calculated capacity of the absorbed dose of γ-radiation conditioned by 40K, 232Th and 226Ra increases from A2 to D2 from 27.5 ± 0.5 to 44.1 ± 1.1 nGy / h at the height of 1 m.

  3. (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).

  4. 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)).

  5. Distribution of 226Ra, 232Th and 40K in soils and sugar cane crops at Corumbataí river basin, São Paulo State, Brazil.

    PubMed

    da Conceição, Fabiano Tomazini; Bonotto, Daniel Marcos; Jiménez-Rueda, Jairo Roberto; Roveda, José Arnaldo Frutuoso

    2009-06-01

    The common use of phosphate fertilizers NPK and amendments in sugar cane crops in Brazilian agriculture may increase the (226)Ra, (232)Th and (40)K activity concentrations in soils and their availability for plants and human food chain. Thus, the main aim of this study was to evaluate the distribution of (226)Ra, (232)Th and (40)K in soils and sugar cane crops in the Corumbataí river basin, São Paulo State, Brazil. The gamma spectrometry was utilized to measure the (226)Ra, (232)Th and (40)K activity concentration in all samples. The soil-to-sugar cane transfer factors (TF) were quantified using the ratio between the radionuclide activity concentration in sugar cane and its activity concentration in soil. The results show that, although radionuclides incorporated in phosphate fertilizers and amendments are annually added in the sugar cane crops, if utilized in accordance with the recommended rates, their use does not lead to hazards levels in soils. The soil-to-sugar cane transfer of radionuclides occurred in the following order (40)K>(226)Ra>(232)Th. Therefore, under these conditions, radionuclides intake through consumption of sugar is not hazardous to human health.

  6. 226Ra, 232Th and 40K contents in water samples in part of central deserts in Iran and their potential radiological risk to human population

    PubMed Central

    2014-01-01

    Background The radiological quality of 226Ra, 232Th and 40K in some samples of water resources collected in Anarak-Khour a desertic area, Iran has been measured by direct gamma ray spectroscopy using high purity germanium detector in this paper. Result The concentration ranged from ≤0.5 to 9701 mBq/L for 226Ra; ≤0.2 to 28215 mBq/L for 232Th and < MDA to 10332 mBq/L for 40K. The radium equivalent activity was well below the defined limit of 370Bq/L. The calculated external hazard indices were found to be less than 1 which shows a low dose. Conclusion These results can be contributed to the database of this area because it may be used as disposal sites of nuclear waste in future. PMID:24883192

  7. 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

  8. Quantification of transfer of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses of a semi-natural ecosystem.

    PubMed

    Dragović, S; Mihailović, N; Gajić, B

    2010-02-01

    There is a lack of appropriate data on transfer of some radionuclides on many terrestrial biota groups. To expand the available data concentration ratios of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses are presented in this paper. The relationship between concentration ratios of radionuclides and physicochemical characteristics of the underlying soil was also investigated. The data on concentration ratios obtained here will provide a useful addition to the currently used database of transfer parameters, particularly for natural radionuclides.

  9. 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

  10. Determination of specific activity of (226)Ra, (232)Th and (40)K for assessment of radiation hazards from Turkish pumice samples.

    PubMed

    Turhan, Seref; Gündüz, Lüfullah

    2008-02-01

    The specific activity of (226)Ra, (232)Th and (40)K in 52 Turkish pumice samples collected from 11 geographical areas located in Central Anatolia, Eastern Anatolia, Mediterranean and Aegean regions was determined by gamma-ray spectrometry with a high-purity germanium (HPGe) detector. The specific activity of (226)Ra, (232)Th and (40)K ranged from 12.7+/-0.5 to 256.2+/-9.1Bqkg(-1) with a mean of 89.1+/-65.2Bqkg(-1), 12.3+/-1.0 to 237.9+/-12.2Bqkg(-1) with a mean of 87.0+/-61.4Bqkg(-1) and 300.1+/-5.5 to 1899.0+/-30.8Bqkg(-1) with a mean of 1211.9+/-419.8Bqkg(-1), respectively. Elemental concentrations were determined for U (from 1.0 to 20.7ppm with a mean of 7.2+/-5.3ppm), Th (from 3.0 to 58.6ppm with a mean of 21.4+/-15.1ppm) and K (from 1.0 to 6.1% with a mean of 3.9+/-1.3%). The radium equivalent activity (Ra(eq)), the activity index, the emanation coefficient, the (222)Rn mass exhalation rate, the indoor absorbed dose rate and the effective dose rate were estimated for the radiation hazard of the natural radioactivity in all samples. The calculated mean Ra(eq) value was 306.6+/-177.7Bqkg(-1) (54.6+/-5.5 to 737.6+/-49.0Bqkg(-1)) for all pumice samples. This value is lower than the recommended limit value of 370Bqkg(-1) for building raws and products. The emanation coefficient and the (222)Rn mass exhalation rate of all samples ranged from 29.4 to 42.9% with a mean of 36.2% and from 11.0 to 196.4microBqkg(-1)s(-1) with a mean of 73.5microBqkg(-1)s(-1), respectively. The mean indoor absorbed dose rate and the corresponding mean effective dose rate were 274.6+/-153.6nGyh(-1) (50.4-644.6nGyh(-1)) and 1.35+/-0.75mSvy(-1) (0.24-3.16mSvy(-1)), respectively. For all pumice samples the mean indoor absorbed dose rate is about three times higher than the population-weighted average of 84nGyh(-1), while the mean effective dose rate values except for PUM 05, PUM 06, PUM 10 and PUM 15 exceed the dose criterion of 1mSvy(-1).

  11. 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.

  12. [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

  13. (226)Ra, (232)Th and (40)K contents and radon exhalation rate from materials used for construction and decoration in Cameroon.

    PubMed

    Ngachin, M; Garavaglia, M; Giovani, C; Nourreddine, A; Kwato Njock, M G; Scruzzi, E; Lagos, L

    2008-09-01

    This work deals with the measurement of radioactivity and radon exhalation rate from building materials manufactured in Douala city from geological materials. Nine types of building material were surveyed for their natural radioactivity contents using high-resolution gamma-ray spectrometry. The activity concentrations for (226)Ra, (232)Th and (40)K varied from 11.5 to 49 Bq kg(-1), 16 to 37 Bq kg(-1) and 306 to 774 Bq kg(-1), respectively. The absorbed dose rate in the samples investigated at 1 m above ground level ranged from 28.5 to 66.6 nGy h(-1). External and internal hazard indices were also estimated as defined by the European Commission. The Ra equivalents of the materials studied ranged from 57.5 to 133 Bq kg(-1) and are much smaller than the recommended limit of 370 Bq kg(-1) for construction materials for dwellings. Polycarbonate nuclear track detectors (NTDs), type CR-39, were used for measuring the radon concentration from different materials. In fact, knowledge of the radon exhalation rate from building materials is important for understanding the individual contribution of each material to the total indoor radon exposure. Samples were hermetically closed in glass vessels and the radon growth was followed as a function of time. The radon exhalation rate was therefore derived from the experimental measurement of alpha-track densities. The radon exhalation varied from (5.77 +/- 0.06) x 10(-5) to (7.61 +/- 0.07) x 10(-5) Bq cm(-2) h(-1) in bricks, from (5.79 +/- 0.05) x 10(-5) to (11.6 +/- 0.12) x 10(-5) in tiles, and was (6.95 +/- 0.03) x 10(-5) Bq cm(-2) h(-1) in concrete. A correlation (correlation coefficient approximately 0.8) was found between radium concentration measured with a HPGe detector and the radon exhalation rate obtained using nuclear track detectors.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 210Pb- 226Ra and 228Ra- 232Th systematics in young arc lavas: implications for magma degassing and ascent rates

    NASA Astrophysics Data System (ADS)

    Turner, Simon; Black, Stuart; Berlo, Kim

    2004-10-01

    New data show that island arc rocks have ( 210Pb/ 226Ra) o ratios which range from as low as 0.24 up to 2.88. In contrast, ( 228Ra/ 232Th) appears always within error of 1 suggesting that the large 226Ra-excesses observed in arc rocks were generated more than 30 years ago. This places a maximum estimate on melt ascent velocities of around 4000 m/year and provides further confidence that the 226Ra excesses reflect deep (source) processes rather than shallow level alteration or seawater contamination. Conversely, partial melting must have occurred more than 30 years prior to eruption. The 210Pb deficits are most readily explained by protracted magma degassing. Using published numerical models, the data suggest that degassing occurred continuously for periods up to several decades just prior to eruption but no link with eruption periodicity was found. Longer periods are required if degassing is discontinuous, less than 100% efficient or if magma is recharged or stored after degassing. The long durations suggest much of this degassing occurs at depth with implications for the formation of hydrothermal and copper-porphyry systems. A suite of lavas erupted in 1985-1986 from Sangeang Api volcano in the Sunda arc are characterised by deficits of 210Pb relative to 226Ra from which 6-8 years of continuous 222Rn degassing would be inferred from recent numerical models. These data also form a linear ( 210Pb)/Pb-( 226Ra)/Pb array which might be interpreted as a 71-year isochron. However, the array passes through the origin suggesting displacement downwards from the equiline in response to degassing and so the slope of the array is inferred not to have any age significance. Simple modelling shows that the range of ( 226Ra)/Pb ratios requires thousands of years to develop consistent with differentiation occurring in response to cooling at the base of the crust. Thus, degassing post-dated, and was not responsible for magma differentiation. The formation, migration and extraction

  19. {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.

  20. 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.

  1. 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

  2. Activity concentrations of 224Ra, 226Ra, 228Ra and 40K radionuclides in refinery products and the additional radiation dose originated from oil residues in Turkey.

    PubMed

    Parmaksiz, A; Agus, Y; Bulgurlu, F; Bulur, E; Yildiz, Ç; Öncü, T

    2013-10-01

    A total of 56 crude oil, refinery product, waste water, sludge and scale samples collected from three refineries were measured by gamma-ray spectrometry. Except for nine samples, all refinery product samples were found to have activity concentrations below the minimum detectable activity (MDA) values. The maximum (224)Ra, (226)Ra, (228)Ra and (40)K activity concentrations in crude oil and refinery product samples were measured as 11.7 ± 4.5, 14.9 ± 3.5, 11.6 ± 4.5, 248.5 ± 18.5 Bq kg(-1), respectively. The maximum (224)Ra, (226)Ra, (228)Ra and (40)K activity concentrations in scale, sludge and water samples were measured as 343.7 ± 11.8, 809.2 ± 29.0, 302.5 ± 21.6, 623.0 ± 80.9 Bq kg(-1), respectively. Radium equivalent activities of the residue samples were calculated up to 1241.8 ± 42.4 Bq kg(-1). The maximum activity concentration index and the alpha index were found to be 4.2 and 4.0, respectively. The annual effective doses of residue samples were calculated below the permitted dose rate for the public, i.e. 1 mSv y(-1).

  3. 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.

  4. 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

  5. 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.

  6. Activity concentrations of 226Ra, 228Th, and 40K in different food crops from a high background radiation area in Bitsichi, Jos Plateau, Nigeria.

    PubMed

    Jibiri, N N; Farai, I P; Alausa, S K

    2007-03-01

    One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. Decades of tin mining in the Bitsichi area of the Jos Plateau, Nigeria, have left a legacy of polluted water supplies, impoverished agricultural land, and soil containing abnormally high levels of naturally occurring radioactive elements. In order to ascertain the radiological food safety of the population, different crops that constitute the major food nutritive requirements were collected directly across farmlands in the area. The activity concentrations of (226)Ra, (228)Th, and (40)K were determined in the food and soil samples using gamma-ray spectrometry. Additionally, in situ gamma dose rate measurements were performed on the farms using a pre-calibrated survey meter. The corresponding activity concentrations in the food crops ranged from below detection limit (BDL) to 684.5 Bq kg(-1) for (40)K, from BDL to 83.5 Bq kg(-1) for (226)Ra, and from BDL to 89.8 Bq kg(-1) for (228)Th. Activity concentrations of these radionuclides were found to be lower in cereals than in tubers and vegetables. As for the soil samples, activity concentrations of these radionuclides varied from BDL to 166.4 Bq kg(-1), from 10.9 to 470.6 Bq kg(-1), and from 122.7 to 2,189.5 Bq kg(-1) for (40)K, (226)Ra, and (228)Th, respectively. Average external gamma dose rates were found to vary across the farms from 0.50 +/- 0.01 to 1.47 +/- 0.04 microSv h(-1). Due to past mining activities, the soil radioactivity in the area has been modified and the concentration level of the investigated natural radionuclides in the food crops has also been enhanced. However, the values obtained suggest that the dose from intake of these radionuclides by the food crops is low and that harmful health effects are not expected. PMID:17211656

  7. 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

  8. 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.

  9. 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.

  10. 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).

  11. Occurrence of 222Rn, 226Ra, 228Ra and U in groundwater in Fujian Province, China.

    PubMed

    Zhuo, W; Iida, T; Yang, X

    2001-01-01

    222Rn, 226Ra, 228Ra and U were determined in a total of 552 groundwater samples collected throughout Fujian Province of China. The geometric mean concentrations of 222Rn, 226Ra, 228Ra and total U in the groundwater were 147.8 kBq m-3, 12.7 Bq m-3, 30.2 Bq m-3 and 0.54 microgram kg-1, respectively. High groundwater 222Rn was explained by the predominantly granitic rock aquifers in Fujian. A lifetime risk of 1.7 x 10(-3) was estimated for the ingestion of groundwater 222Rn. High ratios of 228Ra to 226Ra contents (geometric mean of 2.4) and their disproportion suggest that 228Ra should also be measured in the assessment of population doses from drinking water in the regions of high rock or soil 232Th. No significant correlation between the 222Rn concentrations in groundwater and air was found.

  12. Radium isotopes ((226)Ra and (228)Ra) in Na-Cl type groundwaters from Tohoku District (Aomori, Akita and Yamagata Prefectures) in Japan.

    PubMed

    Tomita, Jumpei; Zhang, Jing; Yamamoto, Masayoshi

    2014-11-01

    A total of 28 Na-Cl type groundwater samples were collected from Aomori, Akita and Yamagata Prefectures, in the Tohoku District of Japan, and their radium isotope ((226)Ra and (228)Ra) concentrations were measured along with their chemical components and stable isotope ratios (δ(2)H and δ(18)Os). The (226)Ra concentrations in groundwater samples varied widely, ranging from 8.8 to 1587 mBq kg(-1). These concentrations showed an increasing tendency with the increase of the total dissolved solid (TDS) contents. The (228)Ra/(226)Ra activity ratios were in the range from 0.3 to 4.2, with most data being around 0.5-2. These ratios were within those of (232)Th/(238)U found in granitic and related rocks and so on in Japan, indicating that Ra isotopes mainly ejected into the groundwater by the alpha-recoil process. The relationship between (226)Ra and other parameters suggested that Ra isotopes in groundwater samples in this study were mainly constrained by adsorption-desorption reactions depending on salinity with wide variation. Clear correlation between (226)Ra-Ca, (226)Ra-Sr, (226)Ra-Ba and (226)Ra-TDS observed in sulfate-free groundwater samples indicated that Ra isotopes of them were constrained by adsorption-desorption reactions depending on salinity under reducing condition. In contrast, relationship of (226)Ra-Ca, (226)Ra-Sr, (226)Ra-Ba and (226)Ra-TDS in sulfate-containing groundwater samples varied widely, and then, removal or enhanced mobility of Ra isotopes of them were observed.

  13. Radium isotopes ((226)Ra and (228)Ra) in Na-Cl type groundwaters from Tohoku District (Aomori, Akita and Yamagata Prefectures) in Japan.

    PubMed

    Tomita, Jumpei; Zhang, Jing; Yamamoto, Masayoshi

    2014-11-01

    A total of 28 Na-Cl type groundwater samples were collected from Aomori, Akita and Yamagata Prefectures, in the Tohoku District of Japan, and their radium isotope ((226)Ra and (228)Ra) concentrations were measured along with their chemical components and stable isotope ratios (δ(2)H and δ(18)Os). The (226)Ra concentrations in groundwater samples varied widely, ranging from 8.8 to 1587 mBq kg(-1). These concentrations showed an increasing tendency with the increase of the total dissolved solid (TDS) contents. The (228)Ra/(226)Ra activity ratios were in the range from 0.3 to 4.2, with most data being around 0.5-2. These ratios were within those of (232)Th/(238)U found in granitic and related rocks and so on in Japan, indicating that Ra isotopes mainly ejected into the groundwater by the alpha-recoil process. The relationship between (226)Ra and other parameters suggested that Ra isotopes in groundwater samples in this study were mainly constrained by adsorption-desorption reactions depending on salinity with wide variation. Clear correlation between (226)Ra-Ca, (226)Ra-Sr, (226)Ra-Ba and (226)Ra-TDS observed in sulfate-free groundwater samples indicated that Ra isotopes of them were constrained by adsorption-desorption reactions depending on salinity under reducing condition. In contrast, relationship of (226)Ra-Ca, (226)Ra-Sr, (226)Ra-Ba and (226)Ra-TDS in sulfate-containing groundwater samples varied widely, and then, removal or enhanced mobility of Ra isotopes of them were observed. PMID:25113929

  14. 238U sbnd 230Th sbnd 226Ra disequilibria in young Mount St. Helens rocks: time constraint for magma formation and crystallization

    NASA Astrophysics Data System (ADS)

    Volpe, Alan M.; Hammond, Paul E.

    1991-12-01

    We use 238U-series nuclides and 230Th/ 232Th ratios measured by mass spectrometry to constrain processes and time scales of calc-alkaline magma genesis at Mount St. Helens, Washington. Olivine basalt, pyroxene andesites and dacites that erupted 10-2 ka ago show 3-14% ( 230Th) sbnd ( 238U) and 6-54% 226Ra sbnd 230Th disequilibria. Mineral phases exhibit robust ( 226Ra) sbnd ( 230Th) fractionation. Plagioclase has large 65-280% ( 226Ra) excesses, and magnetite has large 65% ( 226Ra) deficits relative to ( 230Th). Calculated partition coefficients for Ba, Th, and U in mineral-groundmass pairs, except Ba in plagioclase, are low (⩽ 0.04). Correlation between ( 226Ra/ 230Th ) activity ratios and rm/BaTh element ratios in the minerals suggests that 226Ra partitions similar to Ba during crystallization. Internal ( 230Th) sbnd ( 238U) isochrons for 1982 summit and East Dome dacites and Goat Rocks and Kalama andesites show that closed Th sbnd U system fractionation occurred 2-6 ka ago. Apparent internal isochrons for Castle Creek basalt (34 ka) and andesite (27 ka) suggest longer magma chamber residence times and mixing of old crystals and young melt. Mineral ( 226Ra) sbnd ( 230Th) disequilibrium on Ba-normalized internal isochron diagrams suggests average magma chamber residence times of 500-3000 years. In addition, radioactive ( 226Ra/ 230Th ) heterogeneity between minerals and groundmass or whole rock is evidence for open-system Ra sbnd Th behavior. This heterogeneity suggests there has been recent, post-crystallization, changes in melt chemical composition that affected 226Ra more than 230Th. Clearly, magma fractionation, residence and transport of crystal-melt before eruption of chemically diverse lavas at Mount St. Helens occurs over geologically short periods.

  15. 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.

  16. 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.

  17. 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.

  18. 226Ra and 228Ra in Iowa drinking water.

    PubMed

    Kriege, L B; Hahne, R M

    1982-10-01

    The University Hygienic Laboratory has been performing radiochemical analyses on drinking water in the state of Iowa for over 20 yr. Approximately one half of the 1250 community water supplies that exist in Iowa have been sampled roughly once every 3 yr for the past decade. Originally, raw and finished waters that showed a gross alpha activity of greater than or equal to 3.0 pCi/L were analyzed for 226Ra, but starting in July 1976, finished waters were analyzed for both 226Ra and 228Ra if the gross alpha activity was greater than or equal to 2.0 pCi/L. As of 10 June 1981, 604 community water supplies had submitted composited samples that have been analyzed for gross alpha, 226Ra, and 228Ra concentrations in compliance with the federal Safe Drinking Water Act (Public Law 93-523). Approximately 10% of these supplies were found to exceed the EPA-established maximum contaminant level (MCL) for 226Ra plus 228Ra of 5 pCi/L. The results revealed, consistent with several other investigators (Mc81; Mi80; Mic80), that some supplies had higher concentrations of 228Ra than of 226Ra. It was also concluded, in agreement with McCurdy and Mellor (Mc81), that some ground water samples cannot be accurately measured for gross alpha activity due to their high dissolved solids content. PMID:7152914

  19. Decay of sup 226 Ra by sup 14 C emission

    SciTech Connect

    Weselka, D.; Hille, P.; Chalupka, A. )

    1990-02-01

    Previous observation of heavy-ion emission from {sup 226}Ra has been confirmed. Charge and energy of the emitted fragment were measured using thin {sup 226}Ra sources and polycarbonate track-recording films. Decay by {sup 14}C emission could be identified unambiguously. The track-detector was calibrated with tandem-accelerated {sup 14}C and {sup 16}O ions and tested by observing the {sup 14}C emission from {sup 223}Ra yielding a branching ratio of (5.0{plus minus}1.0){times}10{sup {minus}10}. In the case of {sup 226}Ra our result for the {sup 14}C/{alpha} ratio is (2.3{plus minus}0.8){times}10{sup {minus}11}. Estimates of partial half-lives of Ra isotopes for {sup 14}C emission are discussed.

  20. Rapid determination of 226Ra in emergency urine samples

    DOE PAGES

    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

  1. An Excess 226Ra Geochronology for Saanich Inlet

    NASA Astrophysics Data System (ADS)

    Grayson, R. P.; Plater, A. J.; Boyle, J. F.; Appleby, P. G.

    2004-12-01

    When examining past environmental and climatic change the ability to date both freshwater and marine sediments is essential. Numerous methods are currently available, however where present techniques fail, novel dating techniques are required to overcome these obstacles. In particular the use of 14C to date sediments over the Holocene period can be severely limited where there are significant hard-water and reservoir effects and where reworking of organic matter occurs. The use of unsupported or excess 226Ra offers a potential dating tool in such depositional contexts over the Holocene time period as a result of its half-life of 1600 years. Indeed, the technique has been applied to a number of environments since first being proposed by Koide et al. (1976). However, numerous question marks still surround the application of the technique, particularly with reference to the dating of sub-aqueous sediment deposits. As part of wider research into the applicability of excess 226Ra to date lake sedimentary environments, deep-sea samples from Saanich Inlet were obtained from the ODP (Leg 169S) in order to validate the dating technique. Saanich Inlet is an anoxic fjord located on the coastline of Vancouver Island, British Colombia, the sediments of which have been shown to be comprised of lamina-scale alternations between diatom-rich and diatom-poor clays and silts representing annual. Using digital sediment colour analysis Nederbragt and Thurow (2001) constructed a varve chronology for the last 6000 years. Alpha-spectrometry was successfully used to measure 226Ra, 230Th and 234U in sediment samples collected from Saanich Inlet during ODP Leg 169S. These activities were used to determine an excess 226Ra geochronology for Saanich Inlet. This radiometric chronology compares well with dates obtained from the varve record, and spans two different phases of sediment accumulation.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 228Ra/ 226Ra and 226Ra/Ba ratios in the Western Mediterranean Sea: Barite formation and transport in the water column

    NASA Astrophysics Data System (ADS)

    van Beek, P.; Sternberg, E.; Reyss, J.-L.; Souhaut, M.; Robin, E.; Jeandel, C.

    2009-08-01

    226Ra, 228Ra and Ba distributions as well as 228Ra/ 226Ra and 226Ra/Ba ratios were measured in seawater, suspended and sinking particles at the DYFAMED station in the Western Mediterranean Sea at different seasons of year 2003 in order to track the build-up and fate of barite through time. The study of the 228Ra ex/ 226Ra ex ratios (Ra ex = Ra activities corrected for the lithogenic Ra) of suspended particles suggests that Ba ex (Ba ex = Ba concentrations corrected for the lithogenic Ba, mostly barite) formation takes place not only in the upper 500 m of the water column but also deeper (i.e. throughout the mesopelagic layer). Temporal changes in the 228Ra ex/ 226Ra ex ratios of sinking particles collected at 1000 m depth likely reflect changes in the relative proportion of barite originating from the upper water column (with a high 228Ra/ 226Ra ratio) and formed in the mesopelagic layer (with a low 228Ra/ 226Ra ratio). 228Ra ex/ 226Ra ex ratios measured in sinking particles collected in the 1000 m-trap in April and May suggest that barite predominantly formed in the upper water column during that period, while barite found outside the phytoplankton bloom period (February and June) appears to form deeper in the water column. Combining ratios of both the suspended and sinking particles provides information on aggregation/disaggregation processes. High 226Ra ex/Ba ex ratios were also found in suspended particles collected in the upper 500 m of the water column. Because celestite is expected to be enriched in Ra [Bernstein R. E., Byrne R. H. and Schijf J. (1998) Acantharians: a missing link in the oceanic biogeochemistry of barium. Deep-Sea Res. II45, 491-505], acantharian skeletons may contribute to these high ratios in shallow waters. The formation of both acantharian skeletons and barite enriched in 226Ra may thus contribute to the decrease in the dissolved 226Ra activity and 226Ra/Ba ratios of surface waters observed between February and June 2003 at the DYFAMED

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

    DOE PAGES

    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.

  8. 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.

  9. Leachable 226Ra in Philippine phosphogypsum and its implication in groundwater contamination in Isabel, Leyte, Philippines.

    PubMed

    Cañete, Socrates Jose P; Palad, Lorna Jean H; Enriquez, Eliza B; Garcia, Teofilo Y; Yulo-Nazarea, Teresa

    2008-07-01

    Phosphogypsum (PG), the major waste material in phosphate fertilizer processing, has been known to contain enhanced levels of naturally-occurring radionuclides especially (226)Ra. The lack of radioactivity data regarding Philippine phosphogypsum and its environmental behavior in the Philippine setting has brought concern on possible contamination of groundwater beneath the phosphogypsum ponds in Isabel, Leyte, Philippines. The radioactivity of Philippine phosphogypsum was determined and the leaching of (226)Ra from phosphogypsum and through local soil was quantified. Level of (226)Ra in groundwater samples in Isabel, Leyte, Philippines was also quantified to address the primary concern. It was found that the (226)Ra activity in Philippine phosphogypsum is distributed in a wide range from 91.5 to 935 Bq/kg. As much as 5% of (226)Ra can be leached from Philippine PG with deionized water. In vitro soil leach experiments suggest that the soil in the phosphate fertilizer plant area would be able to deter the intrusion of (226)Ra into the water table. Compared to reported values of natural groundwater levels of (226)Ra, the concentration of this radionuclide in Isabel, Leyte groundwater suggest that there is no (226)Ra intrusion brought about by the presence of phosphogypsum ponds in the area.

  10. A beta-alpha coincidence counting system for measurement of trace quantities of 238U and 232Th in aqueous samples at the Sudbury Neutrino Observatory.

    NASA Astrophysics Data System (ADS)

    Dawson, M.; Doucas, G.; Fergani, H.; Jelley, N. A.; Majerus, S.; O'Keeffe, H. M.; Peeters, S. J. M.; Perry, C.

    2016-08-01

    The Sudbury Neutrino Observatory experiment was built to measure the total flux of 8B solar neutrinos via the neutral current disintegration deuterium nuclei. This process can be mimiced by daughter isotopes of 232Th and 238U which can photodisintegrate the deuterium nucleus. Measurement of the concentration of such radioisotopes in the heavy water was critical to the success of the experiment. A radium assay technique using Hydrous Titanium Oxide coated filters was developed for this purpose and it was used in conjunction with a delayed beta-alpha coincidence counting system. The design, calibration and operation of this counting system are described in this paper. The counting efficiency for 232Th (224Ra) and 238U (226Ra) were measured to be 50 ± 5% and 62 ± 7%

  11. 238U- and 232Th-decay series constraints on the timescales of crystal fractionation to produce the phonolite erupted in 2004 near Tristan da Cunha, South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Reagan, Mark K.; Turner, Simon; Legg, Matthew; Sims, Kenneth W. W.; Hards, Victoria L.

    2008-09-01

    Phonolite pumice found floating offshore of Tristan da Cunha following intense seismic activity southeast of the island July 29-30, 2004 was analyzed for 238U- and 232Th-series nuclides to determine initial 230Th, 226Ra, 210Pb, 210Po, 228Ra, and 228Th activities. The initial ( 210Po/ 210Pb) value of 0.15 for the phonolite shows that, like most subaerial lavas, this subaqueous tephra degassed most of its 210Po upon eruption. The ( 230Th/ 232Th) and ( 238U/ 232Th) values for the phonolite are similar to those of the trachyandesites erupted in 1961 from Tristan da Cunha. However, the relative activities of 210Pb, 226Ra, and 230Th in the phonolite contrast with those of the trachyandesites, in that 210Pb and 230Th are both strongly enriched with respect to 226Ra. In addition, the phonolite had a small deficit in 228Ra with respect to 232Th. The Ra deficits likely resulted from partitioning into feldspars and hornblende in a time frame that extended over several decades to a century. These disequilibria can be explained by crystal fractionation at a decreasing rate through time at an average of 3-5 × 10 -3 year -1. The calculated crystallization rate is about an order of magnitude faster than has been calculated for most other phonolites and trachytes, and about half that calculated for crystallization of the Makaopuhi lava lake. These data imply that the 2004 magma was not the differentiated cap of a much larger body that remained at depth. Instead, it was likely the residue of a relatively small body of more mafic magma that was injected into the crust southeast Tristan and underwent extensive and rapid crystal fractionation before it erupted.

  12. 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

  13. 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.

  14. 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.

  15. 210Pb-226Ra disequilibria in Icelandic basalts and implications for melt transport time

    NASA Astrophysics Data System (ADS)

    Sigmarsson, O.

    2003-04-01

    Primitive basalts with radioactive disequilibrium between isotopes of the 238U decay chain may provide constraints on the timescales of mantle melt migration. The disequilibria between 238U, 230Th and 226Ra have been studied in several Recent basalts whereas very few results exist on the 210Pb-226Ra disequilibria. Only basalts significantly younger than 100 years old can be studied for 210Pb-226Ra disequilibria due to the short half-live of 210Pb (22.3 years). Most lavas measured so far show either 210Pb-226Ra equilibria or 210Pb-deficit which have been attributed to the degassing of 222Rn in shallow magma chambers. Icelandic tholeiites from the last century are in radioactive equilibrium with (210Pb/226Ra) equal to unity. These basalts are fed from shallow magma chambers having residence time exceeding 100 years. In contrast, primitive alkaline basalts (MgO =7-12%) from Surtsey island had (210Pb/226Ra) ranging from 0.45±0.04 to 0.82±0.06 at the time of eruption. These large 210Pb deficits are unlikely to result from shallow magma degassing since no magma chamber existed beneath this volcanic island which was born during the 1963-67 eruption. The 210Pb-226Ra disequilibria increase from the beginning towards the end of the eruption when the most primitive basalts were produced, and decreases systematically with increasing Th content. These same basalts show a negative correlation between Pb and Cu abundances which are inconsistent with exsolution of sulfur rich liquid or crystallisation of sulphides as a fractionation mechanism of 210Pb and 226Ra. The large deficit of 210Pb in Surtsey lavas were thus most likely generated during mantle partial melting. In such a case, the time of melt transport from the source region to surface is constrained to be significantly shorter than 100 years.

  16. 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.

  17. Surface water mixing estimated from 228Ra and 226Ra in the northwestern North Pacific.

    PubMed

    Kawakami, Hajime; Kusakabe, Masashi

    2008-08-01

    We investigated the horizontal distributions of (228)Ra and (226)Ra in surface waters of the northwestern North Pacific Ocean and Okhotsk Sea. Ratios of (228)Ra/(226)Ra were relatively large in the Tsugaru Current (0.6-0.8) and Okhotsk Sea (0.4-0.5), and small in the Western Subarctic Gyre (<0.2) and the Oyashio (0.25-0.3). (228)Ra/(226)Ra ratios in western Subarctic Water (SAW) rose slightly upon mixing with Okhotsk Water (OKW), before becoming the Oyashio Water (OYW). Also, ratios in the OYW increased during mixing with Tsugaru Current Water (TCW). Estimating from (228)Ra/(226)Ra ratios and (226)Ra activities with a simple two-end members-mixing model, we assumed that approximately 23% of the OYW originated from the OKW and the coastal region off northern Honshu (Japan) was strongly influenced by the TCW. From a diagram of (228)Ra activities against salinity, we could roughly divide surface seawater in the study area into the five water masses, which were SAW, OYW, OKW, TCW, and Subtropical Water (STW).

  18. An emergency radiobioassay method for 226Ra in human urine samples.

    PubMed

    Sadi, Baki B; Li, Chunsheng; Kramer, Gary H

    2012-08-01

    A new radioanalytical method was developed for rapid determination of (226)Ra in human urine samples. The method is based on organic removal and decolourisation of a urine sample by a polymeric (acrylic ester) solid phase sorbent material followed by extraction and preconcentration of (226)Ra in an organic solvent using a dispersive liquid-liquid microextraction technique. Radiometric measurement of (226)Ra was carried out using a liquid scintillation counting instrument. The minimum detectable activity for the method (0.15 Bq l(-1)) is lower than the required sensitivity of 0.2 Bq l(-1) for (226)Ra in human urine samples as defined in the requirements for radiation emergency bioassay techniques for the public and first responders based on the dose threshold for possible medical attention recommended by the International Commission on Radiological Protection (ICRP). The accuracy (expressed as relative bias, B(r)) and repeatability of the method (expressed as relative precision, S(B)) evaluated at the reference level (2 Bq l(-1)) were found to be -4.5 and 2.6 %, respectively. The sample turnaround time was <5 h for a single urine sample and <20 h for a batch of six urine samples. With the fast sample turnaround time combined with the potential to carry out the analysis in a field deployable mobile laboratory, the newly developed method can be used for emergency radiobioassay of (226)Ra in human urine samples following a radiological or nuclear accident.

  19. 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).

  20. 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

  1. 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.

  2. A rapid and inexpensive method for 226Ra and 228Ra measurements of high TDS groundwaters.

    PubMed

    El-Shrakawy, A; Ebaid, Y Y; Burnett, W C; Aldaihan, Soaad K

    2013-07-01

    A series of laboratory-scale studies was conducted by preconcentrating (226)Ra from spiked water test samples using Purolite ion-exchange resin to evaluate the adsorption efficiency of the resin under varying conditions. After removing the resin from the columns, it was sealed in gas-tight containers and measured via gamma spectrometry. The Purolite resin showed high radium uptake and retention from natural waters in the presence of high iron and total dissolved solids (TDS). This procedure allowed us to process a large number of high TDS samples at a typical rate of 15 samples/day using three germanium detectors. Quality assurance and method validation have been achieved by analyzing selected groundwater samples, with different (226)Ra activities and high TDS values, and comparing the results to those using alpha spectrometry with a (133)Ba yield tracer. There was very good agreement between the obtained (226)Ra activities by both methods.

  3. Removal of 226Ra and 228Ra from TENORM sludge waste using surfactants solutions.

    PubMed

    Attallah, M F; Hamed, Mostafa M; El Afifi, E M; Aly, H F

    2015-01-01

    The feasibility of using surfactants as extracting agent for the removal of radium species from TENORM sludge produced from petroleum industry is evaluated. In this investigation cationic and nonionic surfactants were used as extracting agents for the removal of radium radionuclides from the sludge waste. Two surfactants namely cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX100) were investigated as the extracting agents. Different parameters affecting the removal of both (226)Ra and (228)Ra by the two surfactants as well as their admixture were studied by the batch technique. These parameters include effect of shaking time, surfactants concentration and temperature as well as the effect of surfactants admixture. It was found that, higher solution temperature improves the removal efficiency of radium species. Combined extraction of nonionic and cationic surfactants produces synergistic effect in removal both (226)Ra and (228)Ra, where the removals reached 84% and 80% for (226)Ra and (228)Ra, respectively, were obtained using surfactants admixture.

  4. Removal of 226Ra and 228Ra from TENORM sludge waste using surfactants solutions.

    PubMed

    Attallah, M F; Hamed, Mostafa M; El Afifi, E M; Aly, H F

    2015-01-01

    The feasibility of using surfactants as extracting agent for the removal of radium species from TENORM sludge produced from petroleum industry is evaluated. In this investigation cationic and nonionic surfactants were used as extracting agents for the removal of radium radionuclides from the sludge waste. Two surfactants namely cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX100) were investigated as the extracting agents. Different parameters affecting the removal of both (226)Ra and (228)Ra by the two surfactants as well as their admixture were studied by the batch technique. These parameters include effect of shaking time, surfactants concentration and temperature as well as the effect of surfactants admixture. It was found that, higher solution temperature improves the removal efficiency of radium species. Combined extraction of nonionic and cationic surfactants produces synergistic effect in removal both (226)Ra and (228)Ra, where the removals reached 84% and 80% for (226)Ra and (228)Ra, respectively, were obtained using surfactants admixture. PMID:25464043

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. A new two-phase media method for 226Ra activity measurement in water.

    PubMed

    Sohrabi, M; Khodadadi, F

    2015-06-01

    A new two-phase media method was developed for determination of (226)Ra activity in water. The method was calibrated by applying 7 standard (226)Ra waters with known activities. The method detects alphas in two media; 80 ml of water in a glass bottle with air or a non-polar liquid such as olive oil on top of the water. Alpha particles from (226)Ra, (222)Rn and progeny were detected by two polycarbonate track detectors (PCTDs) which were mounted on a holder inserted in the bottle so that one PCTD is placed in water and the other in air or in the non-polar liquid. The bottles were hermetically sealed and kept for 40 or 48 d. The PCTDs in the bottles shaken every other day enhanced the sensitivity of the measurements. The Calibration Factors for the standard (226)Ra waters, air and olive oil above water are, respectively, (7.85 ± 0.25) × 10(-3), (7.94 ± 0.13) × 10(-3) and 3.02 × 10(-2) tracks.cm(-2) kBq(-1) h(-1) m(3). PMID:25971343

  12. 226Ra-in marine barite: relationship with carbonate dissolution and sediment focusing in the equatorial pacific

    NASA Astrophysics Data System (ADS)

    van Beek, P.; Reyss, J.-L.; DeMaster, D.; Paterne, M.

    2004-02-01

    Sedimentation rates were determined from the 226Ra ( T 1/2=1602 a) decay in barite in seven cores collected from the western, central and eastern equatorial Pacific. Timing of the last carbonate dissolution increase was investigated with this new chronometer. However, an unconformity in the 226Ra-in-barite profiles was observed at some sites, which could be related to this carbonate dissolution event. We discuss different mechanisms that may have generated these unconformities, including (1) bioturbation, (2) possible bias in the estimate of the correction for supported 226Ra activities, (3) changes in the 226Ra/Ba ratio within surface waters and (4) processes that may have affected the 226Ra/Ba ratio recorded in barite, either within the water column or at the sediment-water interface. Among the processes invoked, an increase in the sediment focusing during the Holocene constitutes the mechanism that can most likely explain the observed unconformities. An increase in the sediment redistribution by bottom currents would enhance the lateral transport of old resuspended barite crystals (with a low 226Ra/Ba ratio). The 226Ra/Ba ratio of barite that accumulates in the sediments, therefore, may have decreased, leading to the unconventional 226Ra-profile shape observed in several cores. A change in the chemistry of the bottom waters that transport the resuspended sediment may have also affected the sediment carbonate contents.

  13. Occurrence of 224Ra, 226Ra, 228Ra, gross alpha, and uranium in California groundwater.

    PubMed

    Ruberu, Shiyamalie R; Liu, Yun-Gang; Perera, S Kusum

    2005-12-01

    One hundred and twelve groundwater wells sampled from all the major aquifers in California were analyzed for 224Ra, 226Ra, 228Ra, gross alpha, and uranium. The results showed that radium is found in relatively low concentration, 1.56 x 10(-2)-1.23 Bq L(-1) (0.42-33 pCi L(-1)) for 224Ra, 2.2 x 10(-3)-0.81 Bq L(-1) (0.06-22 pCi L(-1)) for 226Ra, and 8.5 x 10(-3)-1.31 Bq L(-1) (0.23-35 pCi L(-1)) for 228Ra in California groundwater. Uranium was found at the highest concentration on both mass and activity basis and was correlated with the gross alpha measurement. Short-lived radioisotopes showed no significant contribution to gross alpha measurements. There was a strong correlation between 224Ra and 228Ra activities, suggesting the latter to be an indicator for the occurrence of the former. Comparison of 226Ra to 238U, 224Ra to 226Ra, and 226Ra to 228Ra showed scattered data indicating no correlation between each of these isotope pairs. Approximately 4% of the wells were found to exceed the U.S. Environmental Protection Agency (EPA) established maximum contaminant level for total radium of 0.185 Bq L(-1) (5 pCi L(-1)). Analysis of 228Ra by gamma-ray spectroscopy was in good agreement with the U.S. EPA-approved procedure.

  14. Correction methodology for the spectral interfering γ-rays overlapping to the analytical peaks used in the analysis of 232Th.

    PubMed

    Yücel, H; Köse, E; Esen, A N; Bor, D

    2011-06-01

    In the γ-ray spectrometric analysis of the radionuclides, a correction factor is generally required for the spectral interfering γ-rays in determining the net areas of the analytical peaks because some interfering γ-rays often might contribute to the analytical peaks of interest. In present study, a correction methodology for the spectral interfering γ-rays (CSI) is described. In particular, in the analysis of (232)Th contained in samples, the interfering γ-rays due to (226)Ra, (235)U, (238)U and their decay products often overlap to the peaks of interest from (232)Th decay products, and vise versa. For the validation of the proposed CSI method, several certified reference materials (CRM) containing U and Th were measured by using a 76.5% efficient n-type Ge detector. The required correction factors were quantified for spectral interference, self-absorption and true coincidence summing (TCS) effects for the relevant γ-rays. The measured results indicate that if one ignores the contributions of the interfering γ-rays to the analytical peaks at 583.2 keV of (208)Tl and 727.3 keV of (212)Bi, this leads to a significantly systematic influence on the resulted activities of (232)Th. The correction factors required for spectral interference and TCS effects are estimated to be ∼13.6% and ∼15.4% for 583.2 keV peak. For the 727.3 keV peak, the correction factor is estimated to be ∼15% for spectral interference, and ∼5% for the TCS effects at the presently used detection geometry. On the other hand, the measured results also indicate that ignoring the contribution of the interfering γ-rays to the areas of the analytical peaks at 860.6 keV of (208)Tl, 338.3 and 911.2 keV of (228)Ac does not lead to any significant systematic influence on the (232)Th analysis. Because these factors are remained generally less than ∼5%, i.e., within overall uncertainty limits. The present study also showed that in view of both the spectral interference and TCS effects, the

  15. [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.

  16. 238U, 226Ra and 210Pb in some vent waters of the Galapagos Spreading Center

    NASA Astrophysics Data System (ADS)

    Krishnaswami, S.; Turekian, K. K.

    1982-08-01

    The concentrations of 226Ra, 238U and 210Pb have been measured in waters from the Mussel Bed and the Rose Garden thermal fields at the Galapagos spreading center over a temperature range of ˜2.5-16°C. The 226Ra-T plots yield slopes of 0.112 and 0.036 dpm/kg°C for the Mussel Bed and the Rose Garden respectively yielding a global hydrothermal 226Ra flux less than 5% of that required to sustain the oceanic inventory. 238U concentration in waters <9°C is the same as that in ambient sea water whereas water hotter than ˜9°C shows a decreasing trend with temperature to zero 238U at ˜29°C. 210Pb concentration in Mussel Bed increases with temperature, and extrapolated to ˜350°C yields a 210Pb concentration considerably less than that expected from 222Rn decay and basalt alteration.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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

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

    NASA Astrophysics Data System (ADS)

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

    2005-09-01

    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.

  4. 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.

  5. Self-cleaning in an estuarine area formerly affected by 226Ra anthropogenic enhancements: numerical simulations.

    PubMed

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

    2005-03-01

    A numerical model of the Odiel-Tinto estuary (Spain) has been developed to study the self-cleaning process that was evidenced from 226Ra measurements in water and sediments collected in the period 1999-2002, after direct releases from a fertilizer complex ceased (in 1998). The hydrodynamic model is first calibrated, and standard tidal analysis is carried out to calculate tidal constants required by the dispersion code to determine instantaneous water currents and elevations over the estuary. In this way, long-term simulations may be carried out. The dispersion code includes advective/diffusive transport of radionuclides plus exchanges with bottom sediments described through a kinetic approach. The dispersion model is first tested by comparing computed and measured 226Ra concentrations over the estuary resulting after releases in the Odiel and Tinto rivers. Next, it is applied to simulate the self-cleaning process of the estuary. The time evolution of radium concentrations in bed sediments is in generally good agreement with observations. The computed sediment halving time of the estuary is 510 days, which also is in good agreement with that estimated from measurements.

  6. Natural radioactivity of 226Ra and 228Ra in thermal and mineral waters in Croatia.

    PubMed

    Bituh, Tomislav; Marovic, Gordana; Petrinec, Branko; Sencar, Jasminka; Franulovic, Iva

    2009-01-01

    Thermal waters are known as valuable natural resources of a country. They contain certain degree of natural radioactivity attributable to the elements of the uranium and thorium natural decay series. Among these elements, the most radiotoxic and the most important is radium that exists in several isotopic forms (226Ra and 228Ra). The focus of attention was the content of radium in samples of thermal and mineral spring water from several spas in Croatia. These waters are mainly used for medical, bathing and recreational purposes, and some of them are used for drinking. Measured activity concentrations of 226Ra ranged from 87 to 6200 mBq l(-1) which, in some springs, exceed the maximal permissible level of 1 Bq l(-1) for drinking water. Measured activity concentrations of 228Ra ranged from 23 to 3480 mBq l(-1). The study showed that radium content for the investigated thermal and mineral waters is below the levels at which negative consequences would arise due to ingestion.

  7. Study of the occurrence of 222Rn and 226Ra in drinking water in Spain.

    PubMed

    Soto, J; Fernández, P L; Gómez, J; Ródenas, C

    1995-12-01

    With the aim of determining the contribution of water to the background of natural radiation in Spain, the 222Rn concentration levels were measured in domestic drinking water from a large part of the country. The water analyzed, both surface and groundwater, was collected in two areas of very distinct geological characteristics, pre-selected for the likelihood of their containing high levels of 222Rn. This water was measured using a coaxial detector of high purity Ge. The overall results demonstrate a log-normal distribution of 222Rn levels, with a geometric and arithmetic means of 10 and 381 Bq L-1, respectively, and a range between detection limit of 2 Bq L-1 and a maximum of 31,000 Bq L-1. The 222Rn concentrations measured in surface water are generally below the detection limit. Significant differences have been found depending on the geological characteristics of the area of reference, although the very distinct concentration levels of 222Rn found in samples of similar lithology imply the influence of more complex factors in the solution of 222Rn in water. Due to the relationship between radon and 226Ra, the concentration of the latter was measured in the same water using radiochemical separation and a scintillation ZnS(Ag) detector. No significant correlation between 226Ra and 222Rn concentrations has been observed unless measurements carried out in a high background radiation region are considered separately.

  8. (228)Ra and (226)Ra measurement on a BaSO4 co-precipitation source.

    PubMed

    Medley, Peter; Martin, Paul; Bollhöfer, Andreas; Parry, David

    2014-10-14

    One of the most commonly-used methods for determination of (226)Ra, particularly in water samples, utilises co-precipitation of Ra with BaSO4, followed by microfiltration to produce a source for alpha counting. This paper describes two extensions to BaSO4 co-precipitation methods which enable determination of (228)Ra using the same source. The adaptations presented here do not introduce any contaminants that will affect the separation of radium or alpha counting for (226)Ra, and can be used for re-analysis of already existing sources prepared by BaSO4 co-precipitation. The first adaptation uses detection of (228)Ac on the source by gamma spectrometry. The detection efficiency is high, allowing analysis of water samples at sufficiently low activity to be suitable in testing for compliance with drinking water quality standards. As (228)Ac grows in quickly, taking less than 2 days to reach equilibrium with the (228)Ra parent, this can also be useful in radiological emergency response situations. The second adaptation incorporates a method for the digestion of BaSO4 sources, allowing separation of thorium and subsequent determination of (228)Th activity. Although ingrowth periods for (228)Th can be lengthy, very low detection limits for (228)Ra can be achieved with this technique.

  9. (228)Ra and (226)Ra measurement on a BaSO4 co-precipitation source.

    PubMed

    Medley, Peter; Martin, Paul; Bollhöfer, Andreas; Parry, David

    2014-10-14

    One of the most commonly-used methods for determination of (226)Ra, particularly in water samples, utilises co-precipitation of Ra with BaSO4, followed by microfiltration to produce a source for alpha counting. This paper describes two extensions to BaSO4 co-precipitation methods which enable determination of (228)Ra using the same source. The adaptations presented here do not introduce any contaminants that will affect the separation of radium or alpha counting for (226)Ra, and can be used for re-analysis of already existing sources prepared by BaSO4 co-precipitation. The first adaptation uses detection of (228)Ac on the source by gamma spectrometry. The detection efficiency is high, allowing analysis of water samples at sufficiently low activity to be suitable in testing for compliance with drinking water quality standards. As (228)Ac grows in quickly, taking less than 2 days to reach equilibrium with the (228)Ra parent, this can also be useful in radiological emergency response situations. The second adaptation incorporates a method for the digestion of BaSO4 sources, allowing separation of thorium and subsequent determination of (228)Th activity. Although ingrowth periods for (228)Th can be lengthy, very low detection limits for (228)Ra can be achieved with this technique. PMID:25464199

  10. Accumulation of 210Pb, 226Ra and radioactive cesium by fungi.

    PubMed

    Kirchner, G; Daillant, O

    1998-10-15

    Fungi sampled in three areas in France were analyzed by gamma-spectrometry for their concentrations of 134Cs, 137Cs, 210Pb and 226Ra. In most of the samples radioactive cesium was detected with a maximum of 2860 Bq kg-1 (dry wt.). Activity concentrations of 210Pb were in the range < 1.76-36.5 Bq kg-1 (dry wt.). Activity concentrations of 226Ra were consistently lower, often by one order of magnitude. Models are developed to estimate the contributions of atmospheric 210Pb deposited onto the fruit bodies to the measured 210Pb concentrations and of the uptake of 222Rn soluted in soil pore water which subsequently decays into 210Pb. It is shown that both pathways are of only minor importance. Comparison with the soil-mushroom concentration ratios of stable lead, which were determined for some of the samples, confirmed that 210Pb in mushrooms mainly originates from direct uptake of 210Pb present in the soil. Despite of the high concentrations of 137Cs detected in most of the mushrooms, radiation doses to individuals due to mushroom consumption are dominated by 210Pb for the majority of the edible mushrooms sampled.

  11. 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)

  12. 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.

  13. 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

  14. Magmatic Processes at Loihi Seamount Inferred From 226Ra-230Th-234U-238U Disequilibria

    NASA Astrophysics Data System (ADS)

    Pietruszka, A. J.; Hauri, E. H.; Garcia, M. O.

    2001-12-01

    We have conducted a detailed study of the U-series isotope geochemistry of young tholeiitic, transitional and alkalic Loihi basalts to examine the melt generation process during the preshield stage of a Hawaiian volcano. A previous study (Sims et al. 1999; GCA, v. 63) of two dredged lavas from the deep flanks of Loihi found a higher (230Th/238U) activity ratio in an alkalic basalt (1.07) compared to a tholeiitic basalt (1.04). This difference suggests that the tholeiitic basalt may have formed at a higher rate of mantle upwelling than the alkalic basalt. Our samples were collected from surface lava flows at Loihi's summit and along the volcano's south rift zone by submersible. Analyses were preformed using high-precision plasma ionization mass spectrometry. The samples display a relatively large range in the amount of excess 226Ra (0-13%) that extends to much lower values than observed at Kilauea Volcano (11-12%). The low (226Ra/230Th) ratios of Loihi lavas probably result from post-eruptive decay of 226Ra and imply eruption ages of 0-12 kyr. All of the Loihi samples (including the 1996 lava) have small amounts of excess 234U (0.2-0.8%). The most likely source for (234U/238U)>1 at Loihi is seawater, which has (234U/238U)=1.14. Since all of the samples were fresh, hand-picked glasses, these elevated (234U/238U) ratios may have resulted from the assimilation of a seawater-derived component within Loihi's magmatic plumbing system rather than post-eruptive U addition. The range of (230Th/238U) that we measured is 1.01-1.07, which is larger than the previous range known for Loihi. Mass balance calculations using the measured (234U/238U) ratios suggest that 1-6% of the U in the samples that we analyzed is ultimately derived from seawater. Correcting the 230Th-238U disequilibria of the Loihi lavas for this seawater-derived U results in a narrower range in the amount of excess 230Th (6-9%) with no significant differences between tholeiitic, transitional or alkalic basalts

  15. Evaluation of procedures for (226)Ra determination in samples with high barium concentration by α-particle spectrometry.

    PubMed

    Benedik, L

    2016-03-01

    The γ emitter (133)Ba is the most often used tracer in determination of (226)Ra by α-particle spectrometry. If the source for α-particle spectrometry is prepared by microcoprecipitation, a high Ba concentration causes a thicker source layer which results in reduced counting efficiency due to self-absorption on the α spectrometer and consequently lower result for (226)Ra, while not effecting the measurement of (133)Ba in γ-ray spectrometry. If the electrodeposition is used, recoveries of deposited Ra and Ba are not necessarily the same and impurities of other α emitters may interfere with the α spectrum.

  16. Natural radioactivity content of granite tiles used in Greece.

    PubMed

    Papaefthymiou, H

    2008-01-01

    Measurements of (226)Ra, (232)Th and (40)K activity concentrations in commercial granite tiles imported in Greece were performed using gamma-ray spectrometry. The activity concentration of (226)Ra, (232)Th and (40)K ranged from 1 to 434, 2 to 239 and 71 to 1576 Bq kg(-1), respectively. The calculated activity concentration index (I) values for all granite samples examined were found to be within the EC limit values for superficial and other materials with restricted use.

  17. Doses from 222Rn, 226Ra, and 228Ra in groundwater from Guarani aquifer, South America.

    PubMed

    Bonotto, D M

    2004-01-01

    Groundwater samples were analysed for 222Rn, 226Ra, and 228Ra in Guarani aquifer spreading around 1 million km2 within four countries in South America, and it was found that their activity concentrations are lognormally distributed. Population-weighted average activity concentration for these radionuclides allowed to estimate a value either slightly higher (0.13 mSv/year) than 0.1 mSv for the total effective dose or two times higher (0.21 mSv/year) than this limit, depending on the choice of the dose conversion factor. Such calculation adds useful information for the appropriate management of this transboundary aquifer that is socially and economically very important to about 15 million inhabitants living in Brazil, Argentina, Uruguay and Paraguay.

  18. 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.

  19. 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

  20. Seasonal variations in 228Ra/226Ra ratio within coastal waters of the Sea of Japan: implications for water circulation patterns in coastal areas.

    PubMed

    Inoue, M; Tanaka, K; Watanabe, S; Kofuji, H; Yamamoto, M; Komura, K

    2006-01-01

    In this study, low-background gamma-spectrometry was used to determine the (228)Ra/(226)Ra ratio of 131 coastal water samples from various environments around Honshu Island, Japan (mainly around Noto Peninsula) at 1-3 month intervals from April 2003 until September 2005. Spatial variation in (228)Ra/(226)Ra ratios was also assessed by analyzing 34 coastal water samples from five areas within the Sea of Japan during May and June 2004. The (228)Ra/(226)Ra ratio of coastal water from all sites around Noto Peninsula shows seasonal variation, with minimum values during summer ((228)Ra/(226)Ra=0.7) and maximum values during autumn-winter ((228)Ra/(226)Ra=1.7-2). This seasonal variation is similar to that recorded for coastal water between Tsushima Strait and Noto Peninsula. The measured lateral variation in (228)Ra/(226)Ra ratios within coastal water between Tsushima Strait and Noto Peninsula is only minor (0.5-0.7; May-June 2004). Coastal waters from two other sites (Pacific shore and Tsugaru Strait, north Honshu) show no clear seasonal variation in (228)Ra/(226)Ra ratio. These measured variations in (228)Ra/(226)Ra ratio, especially the temporal variations, have important implications for seasonal changes in patterns of coastal water circulation within the Sea of Japan.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. Behavior of 234U, 238U and 226Ra in shallow aquifers of Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Méjean, P.; Pinti, D. L.; Ghaleb, B. G.; Larocque, M.

    2012-12-01

    A study was initiated in order to quantify the groundwater resources available in two different hydrogeological systems. The first is the Bécancour basin located between Montréal and Québec. Groundwater flow in shallower sands intercalated with clays of the Holocene Champlain Sea and fractured carbonates of Ordovician age of the St. Lawrence Lowlands. The second is composed of unconfined and/or buried fluvioglacial deposits (eskers) produced during the Holocene deglaciation (ca. 8,000 yrs ago) in the region of Amos, Abitibi-Temiscamingue. Presence of uranium and radium is dependent of the redox conditions and the physical/lithological characteristic of aquifers. 234U/238U activity ratios can give precious information on the infiltration conditions at the recharge or the water-rock interactions. 226Ra can allow obtaining residence time in young groundwater thanks to its half-life of 2,622 yrs. In Bécancour basin, there is a clear decreasing trend of the 234U/238U activity ratio along the flow path, from a maximum of 3.12 measured close to the recharge (Appalachian Mts.) to a value of 1.14, on the plain close to the St. Lawrence River (discharge). This trend cannot be related to the radioactive decay of the 234U compared to that of 238U because this would mean a water residence time of 106 yrs timescale, while waters are young and they show the occurrence of tritiogenic 3He. There is a clear relation between the alkalinity of waters (and the HCO3- content) and the 234U/238U activity ratio, suggesting that the mobility of uranium might be related to HCO3- and CO32- ions complex, inducing higher mobility of 234U compared to 238U after its expulsion into water by induced α-recoil. In the region of Amos, Abitibi, preliminary results were obtained on freshwater samples collected in the semi-confined St-Mathieu de Berry, the buried one of Barraute and the unconfined moraine of Harricana. Three samples were collected in a confined saline aquifer in the fractured

  6. Bayesian estimation of the relative toxicity of (239)Pu and (226)Ra with dependent competing risks

    NASA Astrophysics Data System (ADS)

    Xiao, Shili

    The purpose of this dissertation research is to compare the toxicity of the alpha-emitting, bone-seeking radionuclides sp{239}Pu and sp{226}Ra, develop a model for radiation induced osteosarcomas, and analyze the survival data of beagles exposed to these radionuclides. This research integrates the knowledge of radiation protection, survival theory and methods (competing risks, maximum likelihood estimation, and Bayesian techniques), numerical integration techniques (Monte Carlo, Lattice rule and Gauss-quadrature) and object-oriented programming in C++. The outline of this research is: (1) survival data preprocessing, (2) model identification and selection, (3) introduction of FGM model, the dependent competing risk model created by Farlie, Gumbel and Morgenstern, to the study of survival data with dependent competing risks: osteosarcomas and other diseases, development of the crude density of the FGM model and construction of the likelihood function for the FGM model, (4) Bayesian estimates of the posterior marginal density of the toxicity ratio in the FGM model using several numerical integration techniques (Monte Carlo, Lattice rule and Gaussian Quadrature), (5) construction of the likelihood function for the independent competing risk model, Bayesian estimate of the posterior marginal density of toxicity ratio in the model using Monte Carlo method, which is compared with the posterior marginal densities for the toxicity ratio obtained from the FGM model, (6) Bayesian estimates of all other parameters in the FGM model using Monte Carlo method, (7) Comparison of the cumulative hazard for sp{239}Pu calculated according to the model with Nelson's cumulative hazard plot under Bayesian point estimates of parameters and the mean activity in each injection level, (8) Comparison of the toxicity of plutonium in osteosarcoma with that of radium under Bayesian point estimates of parameters an d the selected activit of 0.85 muCsbi, (7) discuss Bayesian prediction of the

  7. 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

  8. 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.

  9. Cleanup protocol for 226Ra-contaminated cobbly soil at UMTRA Project sites.

    PubMed

    Gonzales, D E; Millard, J B; Miller, M L; Metzler, D

    1994-01-01

    The nonuniform distribution of 226Ra and other radiological contamination of cobbly soil encountered on several Uranium Mill Tailings Remedial Action Project sites is presented and discussed, and the concomitant challenges to the intent and implementation of the U.S. Environmental Protection Agency's soil cleanup standards are noted. In response to technical assessments and information presented to the U.S. Nuclear Regulatory Commission by the U.S. Department of Energy, the Nuclear Regulatory Commission has recently resolved the dilemma by concluding that compliance with Environmental Protection Agency soil cleanup standards for cobby soil at Uranium Mill Tailings Remedial Action Project sites would be adequately attained using bulk radionuclide concentrations, instead of requiring that the radionuclide concentration of the finer soil fraction passing a #4 mesh sieve met the standards. A Nuclear Regulatory Commission-approved procedure developed for cobbly soil remediation is outlined and discussed. The site-specific implementation of this procedure at Uranium Mill Tailings Remedial Action Project sites containing cobbly soil is estimated to save millions of dollars.

  10. 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.

  11. Steady-state 226Ra/ 230Th disequilibrium in mantle minerals: Implications for melt transport rates in island arcs

    NASA Astrophysics Data System (ADS)

    Feineman, Maureen D.; DePaolo, Donald J.

    2003-10-01

    Measurements of the concentrations of the 238U decay series isotopes ( 234U, 230Th, 226Ra) have been used to estimate the rates at which magma is generated and transported in the mantle. The usual assumption is that solid mantle minerals are in radioactive equilibrium prior to melting. However, if one or more of the nuclides in the chain is strongly concentrated by a minor mineral, and if the diffusivity of that nuclide is large enough, steady-state radioactive disequilibrium can result in the solid phase. It can be inferred from available data that radium is strongly concentrated in minor hydroxyl-bearing mantle minerals (phlogopite and amphibole) relative to Th, and Ra diffusion in clinopyroxene is fast relative to the typical grain diameter at ca. 1100°C. Consequently, we show with simple analytical models that a steady-state Ra deficiency in clinopyroxene (cpx), accompanied by a complementary steady-state Ra excess in neighboring phlogopite (phlog) or amphibole (amph), is likely to be the normal situation in hydrous mantle peridotite with average clinopyroxene grain radii of ca. 1 mm. The steady state ( 226Ra/ 230Th) (parentheses indicating activity ratio) in the hydrous mineral is limited roughly by the mass ratio with clinopyroxene (i.e. cpx/phlog or cpx/amph) and could be as high as 10-100. The exceptionally high ( 226Ra/ 230Th) of some island arc lavas could therefore be a result of preferential contribution of phlogopite or amphibole during partial melting of hydrous mantle. This effect may ease time constraints for source-to-surface melt migration at island arcs. Incipient melting of hydrous minerals from channel walls during melt transport and/or late-stage incorporation of phlogopite or amphibole into arc magmas may also contribute to generating high ( 226Ra/ 230Th). Steady-state ( 226Ra/ 230Th) disequilibrium due to diffusive loss of 226Ra from clinopyroxene is also important for melt/solid and fluid/solid partitioning, and must be incorporated into

  12. The role of the Ganges-Brahmaputra mixing zone in supplying barium and [sup 226]Ra to the Bay of Bengal

    SciTech Connect

    Carroll, J. Univ. of Alaska, Fairbanks ); Falkner, K.K. CNES, Toulouse ); Brown, E.T. ); Moore, W.S. )

    1993-07-01

    The Ganges-Brahmaputra river system is ranked fourth among world rivers as a source of freshwater to the oceans and is believed to supply more sediment to the ocean than any other; 1.5 [times] 10[sup 12] kg/yr (Milliman and Meade, 1983). Barium and [sup 226]Ra are typically enriched in waters where sediment-laden rivers enter the ocean. As such, the Ganges-Brahmaputra is likely to produce globally significant barium and [sup 226]Ra fluxes to the ocean. Water samples for barium and [sup 226]Ra were collected within four major channels of the Ganges-Brahmaputra mixing zone during a period of low sediment and freshwater discharge. The data suggest that in addition to suspended sediments supplied directly from rivers, river sediments deposited during high discharge in mangroves and on islands are desorbing barium and [sup 226]Ra to seawater. The release of barium and [sup 226]Ra from these sediment deposits is out-of-phase with the direct supply of sediments from the rivers. Estimates of the annual fluxes of barium and [sup 226]Ra from the Ganges-Brahmaputra mixing zone were also derived. The fluxes of barium and [sup 226]Ra are 5.3 [times] 10[sup 8] mol barium/yr and 9.5 [times] 10[sub 14] dpm radium/yr. The first silicate and phosphate mixing profiles for this system are reported. 29 refs., 6 figs., 3 tabs.

  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. 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

  15. Determination of 226Ra, 224Ra, 223Ra and 228Ra in mineral water samples of the Slovak Republic

    NASA Astrophysics Data System (ADS)

    Durecová, A.; Durec, F.; Bursová, D.

    2006-01-01

    The Slovak Republic is very rich in mineral water sources. In recent years, it has been discovered that a number of mineral waters in the Slovak Republic contain high levels of 226Ra and 228Ra. Moreover, there is a lack of information on 224Ra and 223Ra concentrations in mineral waters as well. The currently approved techniques for alpha emitting radium isotopes are based on radon emanation methods. Due to the long ingrowth periods required by these techniques, any 224Ra and 223Ra in the sample decay away and go undetected. For this reason, we have used an alpha spectrometric method for the simultaneous determination of 226Ra, 223Ra and 224Ra. Radium was concentrated by a lead sulphate co-precipitation. The precipitate was dissolved in EDTA and the radium isotopes were separated from possible interfering radionuclides using barium sulphate micro precipitation. The radium-barium precipitate was filtered and counted by alpha spectrometry. 133Ba was used to quantify the yield by gamma spectrometry. In our laboratory, gamma spectrometry was also used for the determination of 228Ra in mineral water samples. Radium was concentrated by a lead-barium sulphate co-precipitation. 133Ba was used to quantify the yield, found to be 97% on the average, by gamma spectrometry. Furthermore, the committed effective doses for 226Ra, 224Ra, 223Ra, 228Ra intake via ingestion of mineral waters for the members of public were calculated.

  16. 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

  17. 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

  18. Seasonal variation of 228Ra/226Ra ratio in seaweed: implications for water circulation patterns in coastal areas of the Noto Peninsula, Japan.

    PubMed

    Inoue, M; Kofuji, H; Yamamoto, M; Komura, K

    2005-01-01

    To examine water circulation patterns of coastal water, 72 seaweed (Sargasso) samples and 27 coastal water samples were collected from coastal areas of the Noto Peninsula, Japan, during the period from December 1998 to June 2002. The (228)Ra and (226)Ra activities of those samples were measured by low-background gamma-ray spectrometry. There was a wide range of activities of (228)Ra (0.5-2Bq/kg-fresh) and (226)Ra (0.5-1.2Bq/kg-fresh) in the Sargasso samples. The (228)Ra/(226)Ra activity ratio of Sargasso samples exhibited seasonal variation with minimum values in June ((228)Ra/(226)Ra= approximately 1) and maximum values in December (1.5-2.5), which was mainly governed by changes in (228)Ra activity. It is also notable that the seasonal variation of the (228)Ra/(226)Ra ratio of Sargasso is in approximate agreement with that of the ambient coastal water. Sargasso samples appear to have retained the (228)Ra/(226)Ra ratio of the ambient coastal waters, and the temporal variations in that ratio provide insight into seasonal changes in water circulation in the Noto Peninsula coastal area.

  19. 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

  20. sup 222 Rn, sup 226 Ra, and sup 228 Ra as tracers for the evolution of warm core rings

    SciTech Connect

    Orr, J.C.

    1988-01-01

    Naturally occurring levels of {sup 228}Ra, {sup 226}Ra, and {sup 222}Rn were measured in and around warm core rings to enhance interpretation provided by conventional conservative tracers. Surplus {sup 222}Rn was found in warm core ring 82B, thereby indicating penetration of rapidly advecting shelf water (transit time {le} 16 days). An in situ pumping system has been developed to rapidly extract {sup 228}Ra from seawater. This instrument may also simplify large-volume sampling for other trace species in seawater. Coincidence counting ({beta}-{gamma}) has been applied to analysis of oceanic {sup 228}Ra, providing precise, low-level determinations shortly after sampling with relatively high counting efficiency (5.3%), low background (0.0054 cpm) and reasonable ease of analytical processing. Results show, {sup 228}Ra activity within ring 82B increased with ring age, marking infiltration of surrounding waters. Also {sup 228}Ra must have been lost from ring 82B before it was 2 months old, an interpretation supported by physical evolution models of ring 82B and distributions of particulate Mn and {sup 228}Ra. Because {sup 226}Ra is not similarly lost, {sup 228}Ra could not have been scavenged. Particulate Mn is the only species found to correlate with {sup 228}Ra. Loss of both species in young ring 82B is attributed to their incorporation into rapidly sinking fecal material. Latter, enhanced zooplankton activity indirectly facilitated solubilization of adsorbed {sup 228}Ra; particles subsequently lost were deficient in {sup 228}Ra. Like warm core rings, the Gulf Stream loses {sup 228}Ra at a rate 60 times faster than explainable by radioactive decay, without corresponding loss of {sup 226}Ra or particulate Ba. Evaluation of counting methods reveals a fivefold sensitivity jump is feasible for {sup 228}Ra.

  1. 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.

  2. 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.

  3. 238U, 226Ra, 210Po concentrations of bottled mineral waters in Hungary and their committed effective dose.

    PubMed

    Kovács, T; Bodrogi, E; Dombovári, P; Somlai, J; Németh, Cs; Capote, A; Tarján, S

    2004-01-01

    Nowadays the consumption of bottled mineral waters has become very popular. The average consumption of these is 0.36 l d(-1) per person in Europe. A considerable segment of the population drinks almost only mineral water as drinking water, which is about 1 l d(-1). As is known, some kinds of mineral waters contain naturally occurring radionuclides in higher concentration than the usual drinking (tap) water. The WHO (1993) legislation concerning the drinking waters does not include the mineral waters. In our work, the concentrations of (226)Ra, (238)U and (210)Po were determined in mineral waters available in Hungary. To determine the (226)Ra concentration the emanation method was used. The (238)U and (210)Po concentrations were determined by alpha spectrometry using semiconductor detector. The dose contribution was calculated using the radionuclide concentrations and the dose conversion factors from the Basic Safety Standard IAEA (1995), for 1 l d(-1) mineral water consumption. In some cases the calculated doses were considerable higher than the limit for drinking waters. Especially for children the doses can be remarkably high.

  4. 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.

  5. 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.

  6. 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

  7. {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.

  8. 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.

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

    DOE PAGES

    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.

  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. 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.

  15. (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...

  16. 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.

  17. Simultaneous determination of 226Ra and 210Pb in groundwater and soil samples by using the liquid scintillation counter-suspension gel method.

    PubMed

    Kim, Y J; Kim, C K; Lee, J I

    2001-02-01

    A method for the simultaneous determination of 226Ra and 210Pb in groundwater and soil samples by liquid scintillation counting was developed. Radium and lead were separated together from the samples as Ba(Ra) x PbSO4 co-precipitate, which was centrifuged and dissolved with 0.1 M EDTA solution (pH 9.0). Radium was separated as Ba(Ra)SO4 co-precipitate by adding ammonium sulfate and adjusting the pH of the solution to 4.2. Lead remaining in the solution was separated as PbSO4 precipitate by adding 9 M sulfuric acid. These Ba(Ra)SO4 and PbSO4 precipitates were purified with EDTA solution and used for measurement. To save time and to make counting samples simpler, direct counting of Ba(Ra)SO4 and PbSO4 precipitates instead of the phosphoric acid fusion method was attempted. Ba(Ra)SO4 and PbSO4 precipitates were suspended in the scintillation gel, and measured. Two liquid scintillation cocktails, Instagel XF and UltimaGold AB were used to prepare the counting samples. A mixture of water (40%), Instagel XF (40%) and UltimaGold AB (20%) formed a stable gel. Activities of 226Ra and 210Pb were calculated from the alpha spectrum of Ba(Ra)SO4 and beta spectrum of PbSO4, respectively. The long-term stability of the suspension gel was good. The analytical results of 226Ra and 210Pb in spiked groundwater samples were in good agreement with the known concentrations of 226Ra and 210Pb. The analytical values of 226Ra and 210Pb in the soil reference samples were within 11.5 and 1.6% of the relative error from the reference values, respectively.

  18. 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.

  19. Charge distribution in the reactor-neutron-induced fission of 232Th

    NASA Astrophysics Data System (ADS)

    Erten, H. N.; Grütter, A.; Rössler, E.; von Gunten, H. R.

    1982-05-01

    The independent yields of 82Br, 86Rb, 96Nb, 98Nbm, 128Sbg, and 136Cs were determined in the reactor-neutron-induced fission of 232Th using radiochemical techniques. Results: (2.3+/-2.3)×10-4% for 82Br, <3.8×10-4% for 86Rb, <4.2×10-5% for 96Nb, (2.48+/-0.53)×10-3% for 98Nbm, (2.34+/-0.37)×10-3% for 128Sbg, and (1.70+/-0.13) ×10-4% for 136Cs. Using the extended Zp model of Wahl with the yield data from this work and the literature the following parameters were obtained for the charge distribution in 232Th fission: width of Gaussian dispersion σ¯Z=0.52+/-0.01, ΔZP (=ZP-ZUCD)=0.45+/-0.02. The even-odd proton and neutron enhancement factors were found to be small. These parameters and systematics of even-odd proton and neutron effects in low energy fission are discussed. NUCLEAR REACTIONS, FISSION Radiochemical fission yields 232Th(n,f), calculated charge dispersion parameters, and odd-even effects.

  20. 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.

  1. 232Th, 233Pa, and 234U capture cross-section measurements in moderated neutron flux

    NASA Astrophysics Data System (ADS)

    Bringer, O.; Isnard, H.; AlMahamid, I.; Chartier, F.; Letourneau, A.

    2008-07-01

    The Th-U cycle was studied through the evolution of a 100 μg 232Th sample irradiated in a moderated neutron flux of 8.010 14 n/cm 2/s, intensity close to that of a thermal molten salt reactor. After 43 days of irradiation and 6 months of cooling, a precise mass spectrometric analysis, using both TIMS and MC-ICP-MS techniques, was performed, according to a rigorous methodology. The measured thorium and uranium isotopic ratios in the final irradiated sample were then compared with integral simulations based on evaluated data; an overall good agreement was seen. Four important thermal neutron-capture cross-sections were also extracted from the measurements, 232Th (7.34±0.21 b), 233Pa (38.34±1.78 b), 234U (106.12±3.34 b), and 235U (98.15±11.24 b). Our 232Th and 235U results confirmed existing values whereas the cross-sections of 233Pa and 234U (both key parameters) have been redefined.

  2. [Mechanisms of 232Th effects on Chlorella vulgaris Beljer and modifications of it's toxic effect with caffeine and buthionine sulfoximine].

    PubMed

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

    2006-01-01

    232Th effects and its modifications with caffeine and D, L-buthionine-(S, R)-sulphoximine in Chlorella vulgaris Beijer cells was studied with use an optical density measure after 24 hours growth. Was shown relationship between concentration and toxic effect that is nonlinear and characterized with three parts different in induced damages level. In the first concentration range (0.001-1.551 micromol/l) chlorella growth parameters don't significantly differ from control ones. In the second one (1.724-3.017 micromol/1) statistically significant increase of optical density is but the effect does not dependent on 232Th concentration. The 232Th concentration (>3.448 micromol/l) increase the monotonous decrease in optical density was observed. The main role in 232Th toxic effect decrease make processes of DNA reparation, but not free radical scavenging with glutathione.

  3. 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.

  4. Mobile gamma-ray scanning system for detecting radiation anomalies associated with /sup 226/Ra-bearing materials

    SciTech Connect

    Myrick, T.E.; Blair, M.S.; Doane, R.W.; Goldsmith, W.A.

    1982-11-01

    A mobile gamma-ray scanning system has been developed by Oak Ridge National Laboratory for use in the Department of Energy's remedial action survey programs. The unit consists of a NaI(T1) detection system housed in a specially-equipped van. The system is operator controlled through an on-board mini-computer, with data output provided on the computer video screen, strip chart recorders, and an on-line printer. Data storage is provided by a floppy disk system. Multichannel analysis capabilities are included for qualitative radionuclide identification. A /sup 226/Ra-specific algorithm is employed to identify locations containing residual radium-bearing materials. This report presents the details of the system description, software development, and scanning methods utilized with the ORNL system. Laboratory calibration and field testing have established the system sensitivity, field of view, and other performance characteristics, the results of which are also presented. Documentation of the instrumentation and computer programs are included.

  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.

    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

  6. Radium isotope ((223)Ra, (224)Ra, (226)Ra and (228)Ra) distribution near Brazil's largest port, Paranaguá Bay, Brazil.

    PubMed

    Dias, Thais H; de Oliveira, Joselene; Sanders, Christian J; Carvalho, Franciane; Sanders, Luciana M; Machado, Eunice C; Sá, Fabian

    2016-10-15

    This work investigates the (223)Ra, (224)Ra, (226)Ra and (228)Ra isotope distribution in river, estuarine waters and sediments of the Paranaguá Estuarine Complex (PEC). The stratification of the Ra isotopes along water columns indicate differing natural sources. In sediments, the radium isotope activities was inversely proportional to the particle size. The highest concentrations of (223)Ra, (224)Ra, (226)Ra and (228)Ra in the water column were found in the bottom more saline waters and towards the inner of the estuary. These relatively high concentrations towards the bottom of the estuary may be attributed to the influence of tidally driven groundwater source and desorption from particles at the maximum turbidity zone. The apparent river water ages from the radium isotope ratios, (223)Ra/(224)Ra and (223)Ra/(228)Ra, indicate that the principal rivers that flow into the estuary have residence times from between 6 and 11days.

  7. [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.

  8. Radium isotope ((223)Ra, (224)Ra, (226)Ra and (228)Ra) distribution near Brazil's largest port, Paranaguá Bay, Brazil.

    PubMed

    Dias, Thais H; de Oliveira, Joselene; Sanders, Christian J; Carvalho, Franciane; Sanders, Luciana M; Machado, Eunice C; Sá, Fabian

    2016-10-15

    This work investigates the (223)Ra, (224)Ra, (226)Ra and (228)Ra isotope distribution in river, estuarine waters and sediments of the Paranaguá Estuarine Complex (PEC). The stratification of the Ra isotopes along water columns indicate differing natural sources. In sediments, the radium isotope activities was inversely proportional to the particle size. The highest concentrations of (223)Ra, (224)Ra, (226)Ra and (228)Ra in the water column were found in the bottom more saline waters and towards the inner of the estuary. These relatively high concentrations towards the bottom of the estuary may be attributed to the influence of tidally driven groundwater source and desorption from particles at the maximum turbidity zone. The apparent river water ages from the radium isotope ratios, (223)Ra/(224)Ra and (223)Ra/(228)Ra, indicate that the principal rivers that flow into the estuary have residence times from between 6 and 11days. PMID:27422485

  9. 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.

  10. 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

  11. (226)Ra measurement by LSC as a tool to assess the efficiency of a water treatment technology for removing radionuclides from groundwater.

    PubMed

    Suursoo, Siiri; Kiisk, Madis; Al-Malahmeh, Amer; Jantsikene, Alar; Putk, Kaisa; Lumiste, Liie

    2014-11-01

    A simple (226)Ra analysis procedure by LSC with an extractive scintillator was tested for evaluating the long-term radionuclides removal efficiency of a water treatment facility at Viimsi, Estonia. During the 14 months of operation, total radium removal efficiency of the treatment process has stayed over 90%, but the removal efficiencies of the different purification steps have varied notably. This demonstrates the need for routine monitoring of radium content in the water treatment plant.

  12. 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

  13. 226Ra, 228Ra and 228Th in scale and sludge samples from the Campos Basin oilfield E&P activities.

    PubMed

    Matta, L E; Godoy, J M; Reis, M C

    2002-01-01

    More than 40 scale and sludge samples from the Campos Basin oilfield were analysed in terms of 226Ra, 228Ra and 228Th. Although the exact origin of the samples was not known, scale samples derived from production pipes and sludge samples from water-oil separation units. Reported values ranged from 0.13 to 331 kBq.kg(-1) for 226Ra, from 0.10 to 245 kBq.kg(-1) for 228Ra and <0.10 to 272 kBq.kg(-1) for 228Th in sludge samples. The concentrations in scales were much more regular than in sludges and ranged from 16.2 to 93.2 kBq.kg(-1) for 226Ra, from 4.0 to 36.9 kBq.kg(-1) for 228Ra and from 4.5 to 18.5 kBq.kg(-1) for 228Th. Based on the Basic Safety Standards recommendations and on the derived results, these activities cannot be regarded as exempted and specific procedures should be designed for their radiological control.

  14. An efficient and simple method for measuring (226)Ra using the scintillation cell in a delayed coincidence counting system (RaDeCC).

    PubMed

    Waska, Hannelore; Kim, Seolwon; Kim, Guebuem; Peterson, Richard N; Burnett, William C

    2008-12-01

    A delayed coincidence counter (RaDeCC), developed to determine ultra-low levels of (223)Ra (half life = 11.1 days) and (224)Ra (half life = 3.6 days) in seawater, was adapted to measure (226)Ra (half life = 1622 years). After pre-concentration of Ra from seawater onto MnO(2)-coated fiber we show in this study that the (226)Ra activity can be determined using the RaDeCC's ability to record alpha decay of its daughters as total counts. For sufficient ingrowth of (222)Rn, the Mn-fiber is hermetically sealed in a column for a few days. Then, the ingrown (222)Rn is circulated through the RaDeCC air-loop system followed by shutting down of the pump and closure of the scintillation cell for equilibration. Counting may be completed within a few hours for seawater samples. Sample measurements with this method agreed well with data obtained using gamma-ray spectrometry. This proves that a set of Ra isotopes ((223)Ra, (224)Ra, and (226)Ra), commonly used for geophysical studies such as mixing rates of different water masses and submarine groundwater discharge, can be efficiently and rapidly measured using the RaDeCC.

  15. Analysis of the distribution characteristics of 226Ra and 228Ra and their sources in the western part of Qinghai Lake

    NASA Astrophysics Data System (ADS)

    Kong, Fancui; Sha, Zhanjiang; Du, Jinzhou; Su, Weigang; Yu, Chenguang; Zhao, Shunli; Hu, Jufang; Ye, Mei

    2015-11-01

    The 226Ra and 228Ra activities of Qinghai Lake surface water, groundwater, river water, suspended particles, and bottom sediments were measured in a gamma-ray spectrometer. The sources of 226Ra and 228Ra were discussed according to their distribution characteristics. 226Ra and 228Ra activities (dpm/(100 L)) ranged from 14.13±0.22 to 19.22±0.42 and 17.72±0.66 to 30.96±1.47 in the surface water of the North Bay, respectively, and from 7.88±0.24 to 33.80±0.47 and 15.73±0.74 to 57.31±1.44, respectively, in the South Bay. The surface water near the estuary had a lower salinity and had a higher concentration of radium isotopes than the samples collected further away. The farther offshore the sample, the higher the salinity was, and the lower the radium isotope activity. The distribution of radium activities in the western part of Qinghai Lake is controlled by several factors, including Buha River runoff, desorption from suspended particles derived from the river, groundwater discharge, and a small amount of diffusion from the sediment.

  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. 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.

  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.

  20. 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

  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. Mass-resolved angular distribution of fission products in the 20Ne+232Th reaction

    NASA Astrophysics Data System (ADS)

    Tripathi, R.; Sodaye, S.; Sudarshan, K.; Guin, R.

    2013-08-01

    Mass-resolved angular distributions of fission product were measured in the 20Ne + 232Th reaction at Elab = 125.6 and 142.5 MeV using the recoil catcher technique followed by offline γ-ray spectrometry. Angular anisotropy was found to decrease with increasing asymmetry of mass division. Angular anisotropies of the fission products in the symmetric region were significantly higher compared to those calculated using the statistical saddle-point model. Experimental anisotropies could be explained after considering the contribution from pre-equilibrium fission. Use of barrier energies corresponding to different mass asymmetry values in the calculations could reasonably reproduce the mass dependence of angular anisotropies. The role of barrier energies in governing the angular anisotropy indicates that the mass dependence of anisotropy may possibly be a distinguishing feature of pre-equilibrium fission from quasifission, in which the composite system escapes into the exit channel without being captured inside the saddle point.

  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. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. An examination of groundwater discharge and the associated nutrient fluxes into the estuaries of eastern Hainan Island, China using 226Ra.

    PubMed

    Su, Ni; Du, Jinzhou; Moore, Willard S; Liu, Sumei; Zhang, Jing

    2011-09-01

    The nutrient concentrations and stoichiometry in a coastal bay/estuary are strongly influenced by the direct riverine discharge and the submarine groundwater discharge (SGD). To estimate the fluxes of submarine groundwater discharge into the Bamen Bay (BB) and the Wanquan River Estuary (WQ) of eastern Hainan Island, China, the naturally occurring radium isotope ((226)Ra) was measured in water samples collected in the bay/estuary in August 2007 and 2008. Based on the distribution of (226)Ra in the surface water, a 3-end-member mixing model was used to estimate the relative contributions of the sources to these systems. Flushing times of 3.9±2.7 and 12.9±9.3 days were estimated for the BB and WQ, respectively, to calculate the radium fluxes for each system. Based on the radium fluxes from groundwater discharge and the Ra isotopic compositions in the groundwater samples, the estimated SGD fluxes were 3.4±5.0 m(3) s(-1) in the BB and 0.08±0.08 m(3) s(-1) in the WQ, or 16% and 0.06%, respectively, of the local river discharge. Using this information, the nutrient fluxes from the submarine groundwater discharge seeping into the BB and WQ regions were estimated. In comparison with the nutrient fluxes from the local rivers, the SGD-derived nutrient fluxes played a vital role in controlling the nutrient budgets and stoichiometry in the study area, especially in the BB.

  11. 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%.

  12. Natural radioactivity and chemical concentrations in Egyptian groundwater.

    PubMed

    Amin, Rafat M; Khalil, F A; El Fayoumi, M A K

    2011-02-01

    Measurements of natural radioactivity in drinking water have been performed in many parts of the world, mostly for assessment of the doses and risk resulting from consuming water. A study of the radionuclide and chemical components in groundwater from Beni Suef Governate, Egypt has been carried out. Fifty water samples were analyzed by gamma ray spectroscopy to determine the 226Ra, 232Th, and 40K concentrations; major elements, pH, alkalinity, and conductivity were also measured. The specific activity values ranged from 0.008 to 0.040 Bq/l for 226Ra, from 0.003 to 0.019 Bq/l for 232Th, and from 0.025 to 0.344 Bq/l for 40K. The annual ingestions of these radionuclides, using local consumption rates (average over the whole population) of 1.5 l day(-1), were estimated to be 8.59, 4.86, and 83.47 Bq year(-1) for 226Ra, 232Th, and 40K, respectively. The estimated values and weighted means of these radionuclides compare well with the world average. The estimated effective doses from drinking water were found to be 2.4 μSv year(-1) (226Ra), 1.1 μSv year(-1) (232Th), and 0.51 μSv year(-1) (40K). Contribution of these radionuclides to the committed effective dose from 1 year consumption of drinking water is estimated to be only 4%.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  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. 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

  20. Short and long term bystander effect induction by fathead minnows (Pimephales promelas, Rafinesque, 1820) injected with environmentally relevant whole body doses of 226Ra.

    PubMed

    Smith, Richard W; Seymour, Colin B; Mothersill, Carmel E

    2013-12-01

    Bystander effect induction by fathead minnows injected with environmentally relevant doses of (226)Ra was investigated. Twenty four h and 6 months after injection with a single dose of 21, 210 or 2100 μBq, fin tissue samples emitted a pro-apoptotic signal, which reduced the clonogenic survival of an apoptosis sensitive reporter cell line. Twenty four h and 10 weeks after injection explants from non-injected bystander fish, swum with the injected fish, also emitted a pro-apoptotic signal. However 6 months after injection the bystander fish to 21 and 210 μBq injected fish emitted an anti-apoptotic signal. This demonstrates that extremely low dose irradiation can have effects outside of the irradiated fish. This has implications for population and ecosystem responses to contamination. PMID:23981564

  1. Radium uptake during barite recrystallization at 23 ± 2 °C as a function of solution composition: An experimental 133Ba and 226Ra tracer study

    NASA Astrophysics Data System (ADS)

    Curti, E.; Fujiwara, K.; Iijima, K.; Tits, J.; Cuesta, C.; Kitamura, A.; Glaus, M. A.; Müller, W.

    2010-06-01

    High-purity synthetic barite powder was added to pure water or aqueous solutions of soluble salts (BaCl 2, Na 2SO 4, NaCl and NaHCO 3) at 23 ± 2 °C and atmospheric pressure. After a short pre-equilibration time (4 h) the suspensions were spiked either with 133Ba or 226Ra and reacted under constant agitation during 120-406 days. The pH values ranged from 4 to 8 and solid to liquid (S/L) ratios varied from 0.01 to 5 g/l. The uptake of the radiotracers by barite was monitored through repeated sampling of the aqueous solutions and radiometric analysis. For both 133Ba and 226Ra, our data consistently showed a continuous, slow decrease of radioactivity in the aqueous phase. Mass balance calculations indicated that the removal of 133Ba activity from aqueous solution cannot be explained by surface adsorption only, as it largely exceeded the 100% monolayer coverage limit. This result was a strong argument in favor of recrystallization (driven by a dissolution-precipitation mechanism) as the main uptake mechanism. Because complete isotopic equilibration between aqueous solution and barite was approached or even reached in some experiments, we concluded that during the reaction all or substantial fractions of the initial solid had been replaced by newly formed barite. The 133Ba data could be successfully fitted assuming constant recrystallization rates and homogeneous distribution of the tracer into the newly formed barite. An alternative model based on partial equilibrium of 133Ba with the mineral surface (without internal isotopic equilibration of the solid) could not reproduce the measured activity data, unless multistage recrystallization kinetics was assumed. Calculated recrystallization rates in the salt solutions ranged from 2.8 × 10 -11 to 1.9 × 10 -10 mol m -2 s -1 (2.4-16 μmol m -2 d -1), with no specific trend related to solution composition. For the suspensions prepared in pure water, significantly higher rates (˜5.7 × 10 -10 mol m -2 s -1 or ˜49 μmol m

  2. 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.

  3. Thorium determination in intercomparison samples and in some Romanian building materials by gamma ray spectrometry.

    PubMed

    Pantelica, A; Georgescu, I I; Murariu-Magureanu, M D; Margaritescu, I; Cincu, E

    2001-01-01

    Thorium content in zircon sand, thorium ore and a thorium liquid sample (EU Laboratories Network Intercomparison), as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement. cement mill dust, coal fly ash, bricks, and tile (28 samples) was deterimined by gamma ray spectrometry. For the building materials, 226Ra, 40K and 137Cs specific activities were also measured. The results were compared with the Romanian legal norms concerning the highest admissible levels for 232Th, 226Ra. and 40K radioactivity. and to Th, U, and K concentration values previously determined in our laboratory on similar types of samples.

  4. 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.; ;

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. Investigation of Nuclear Ground State Properties of Fuel Materials of 232Th and 238U Using Skyrme-Extended-Thomas-Fermi Approach Method

    NASA Astrophysics Data System (ADS)

    Yulianto, Yacobus; Su'ud, Zaki

    2016-08-01

    It has been performed the nuclear ground state properties investigation of 232Th and 238U using Skyrme interaction. The local density, the kinetic energy density, and the spin-orbit density for proton and neutron have been calculated using Extended-Thomas-Fermi approach method. Then the calculation results have been compared with Skyrme-Hartree-Fock results (using HAFOMN and HFBRAD codes). Total energy calculations obtained from this research are -1792.973947 MeV (for 232Th) deviated 0.29244% from experiment energy and -1761.519459 MeV (for 238U) deviated 0.48369% from experiment energy. The distribution profiles of local density and local potential for 232Th and 238U are quite similar with Skyrme- Hartree-Fock results. It is indicated that Skyrme-Extended-Thomas-Fermi method can be used to study the nuclear ground state properties, especially even nuclei.

  12. 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.

  13. Comparative toxicity of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, and /sup 252/Cf in C57BL/Do black and albino mice

    SciTech Connect

    Taylor, G.N.; Mays, C.W.; Lloyd, R.D.; Gardner, P.A.; TAlbot, L.R.; McFarland, S.S.; Pollard, T.A.; Atherton, D.R.; vanMoorhem, D.; Brammer, D.

    1983-09-01

    Groups of C57BL/Do (black and albino) mice were injected with graded activities of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, or /sup 252/Cf and were followed throughout life. Bone sarcoma was the principal radiation-induced end point, and the risks associated with average skeletal doses of the four transuranium radionuclides, relative to radium, were determined. The relative biological effectiveness (RBE) was calculated for each emitter by dividing its risk coefficient (bone sarcomas per 10/sup 6/ mouse-rad) by the risk coefficient for /sup 226/Ra. Combined data for males and females in both black and albino mice gave the following values +- SD for the RBE relative to /sup 226/Ra = 1.0: /sup 239/Pu = 15.3 +- 3.9, /sup 241/Am = 4.9 +- 1.4, /sup 249/Cf = 5.0 +- 1.4, and /sup 252/Cf = 2.6 +- 0.8. About 70% of the tumors occurred in the axial skeleton, and the risk coefficient for females averaged about four times higher than for males when all five nuclides were included. The RBE of fission fragment irradiation from /sup 252/Cf for cancer induction, relative to ..cap alpha.. irradiation, for the combined data in all of the animals given /sup 252/Cf and /sup 249/Cf, was 0.02 +- 0.28, in agreement with the calculated theoretical value of 0.03, based on the ratio of summed track lengths in tissue.

  14. Comparative toxicity of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, and /sup 252/Cf in C57BL/Do black and albino mice

    SciTech Connect

    Taylor, G.N.; Mays, C.W.; Lloyd, R.D.; Gardner, P.A.; Talbot, L.R.; McFarland, S.S.; Pollard, I.A.; Atherton, D.R.; VanMoorhem, D.; Brammer, D.

    1983-09-01

    Groups of C57BL/Do (black and albino) mice were injected with graded activities of /sup 226/Ra, /sup 239/Pu, /sup 241/Am, /sup 249/Cf, or /sup 252/Cf and were followed throughout life. Bone sarcoma was the principal radiation-induced end point, and the risks associated with average skeletal doses of the four transuranium radionuclides, relative to radium, were determined. The relative biological effectiveness (RBE) was calculated for each emitter by dividing its risk coefficient (bone sarcomas per 10(/sup 6/) mouse-rad) by the risk coefficient for /sup 226/Ra. Combined data for males and females in both black and albino mice gave the following values +/- SD for the RBE relative to /sup 226/Ra . 1.0: /sup 239/Pu . 15.3 +/- 3.9, /sup 241/Am . 4.9 +/- 1.4, /sup 249/Cf . 5.0 +/- 1.4, and /sup 252/Cf . 2.6 +/- 0.8. About 70% of the tumors occurred in the axial skeleton, and the risk coefficient for females averaged about four times higher than for males when all five nuclides were included. The RBE of fission fragment irradiation from /sup 252/Cf for cancer induction, relative to alpha irradiation, for the combined data in all of the animals given /sup 252/Cf and /sup 249/Cf, was 0.02 +/- 0.28, in agreement with the calculated theoretical value of 0.03, based on the ratio of summed track lengths in tissue.

  15. 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

  16. 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

  17. 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.

  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. Mass dependence of fragment angular distributions in the fission of 232Th and 236U induced by polarized photons

    NASA Astrophysics Data System (ADS)

    Steiper, F.; Frommhold, Th.; Henkel, W.; Jung, A.; Kneissl, U.; Stock, R.

    1993-10-01

    Near-barrier fission of 232Th and 236U induced by linearly polarized photons has been investigated. The experiments have been carried out at the "off-axis" bremsstrahlung facility of the Giessen 65 MeV electron linac. Fragment angular, mass and energy distributions have been measured simultaneously allowing the investigation of correlations between these fragment characteristics. A consistent assignment of the quantum numbers Jπ and K for the fussion channels involved in the fission process is proposed. For the first time, the polar anisotropies and azimuthal asymmetries of the fission fragment angular distributions W( θ, φ) have been investigated as a function of the fragment masses. The results are discussed in the framework of the double-humped fission barrier concept and the so-called "multi-exit fission channel" model. Additionally, angular distributions of heavy and light fission fragments from photofission of 236U have been analyzed for a possible asymmetry with respect to θ = 90°.

  20. New chronometers for the metamorphism of ophiolitic rocks: 40Ar/39Ar neptunite and 232Th/208Pb joaquinite

    NASA Astrophysics Data System (ADS)

    Borneman, N.; Hodges, K. V.; Van Soest, M. C.

    2015-12-01

    Both primary magmatism and metamorphism of ophiolite sequences are difficult to date, due in large part to the fact that the majority of lithologies present tend to contain very low concentrations of radioactive elements. As a result, researchers are often forced to process large amounts of material to search for accessory phases like zircons in gabbro, or to employ geochronometers that often yield multiply interpretable results (e.g., 40Ar/39Ar glaucophane or phengite), or to rely on indirect evidence for inferring ages. Here, we introduce two new options for chronometery of metamorphosed ophiolites: 40Ar/39Ar neptunite and 232Th/208Pb joaquinite. The best known locality for these rare minerals is the New Idria serpentinite diapir, found within the southern Diablo Range of the Coast Range Province of California. Here, both the joaquinite and neptunite chronometers record indistinguishable dates that we interpret to be the crystallization age of the phases during diapir ascent, based on the demonstrated low temperature history of the diapir as whole and the agreement of dates from chromonometers that almost certainly have different closure temperatures. This age is generally inferred to be coincident with the timing of the passage of the Mendocino Triple Junction and associated initiation of the San Andreas fault in this area. We propose that the mean40Ar/39Ar neptunite plateau date of 12.375 ± 0.082 Ma and corroborating 232Th/208Pb joaquinite date (12.08 ± 0.59 Ma) may represent a high-precision constraint on the timing of this event. We also report a second application of these chronometers to samples from the Yarlung suture, which formed at the time of initial India-Eurasia collision in southern Tibet. Here, both chronometers record indistinguishable dates of ca. 52 Ma, which we also interpret as the crystallization age. This age is consistent with most previously published estimates for the timing of the India-Eurasia collision.

  1. 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.

  2. 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

  3. 40 K Fastrac II Test

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A 40 K Fastrac II duration test performed at Marshall Test Stand 116. The purpose of this test was to gauge the length of time between contact of TEA (Triethylenealuminum) and LOX (liquid oxygen) as an ignitor for the Fastrac engine.

  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. 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; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    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.

  6. Fission fragments mass distributions of nuclei populated by the multinucleon transfer channels of the 18O + 232Th reaction

    NASA Astrophysics Data System (ADS)

    Léguillon, R.; Nishio, K.; Hirose, K.; Makii, H.; Nishinaka, I.; Orlandi, R.; Tsukada, K.; Smallcombe, J.; Chiba, S.; Aritomo, Y.; Ohtsuki, T.; Tatsuzawa, R.; Takaki, N.; Tamura, N.; Goto, S.; Tsekhanovich, I.; Petrache, C. M.; Andreyev, A. N.

    2016-10-01

    It is shown that the multinucleon transfer reactions is a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multinucleon transfer channels of the 18O + 232Th reaction are used to study fission of fourteen nuclei 231,232,233,234Th, 232,233,234,235,236Pa, and 234,235,236,237,238U. Identification of fissioning nuclei and of their excitation energy is performed on an event-by-event basis, through the measurement of outgoing ejectile particle in coincidence with fission fragments. Fission fragment mass distributions are measured for each transfer channel, in selected bins of excitation energy. In particular, the mass distributions of 231,234Th and 234,235,236Pa are measured for the first time. Predominantly asymmetric fission is observed at low excitation energies for all studied cases, with a gradual increase of the symmetric mode towards higher excitation energy. The experimental distributions are found to be in general agreement with predictions of the fluctuation-dissipation model.

  7. 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}

  8. 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

  9. 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.

  10. Assessment of radiation hazards due to natural radioactivity in some building materials used in Egyptian dwellings.

    PubMed

    Medhat, M E

    2009-02-01

    Different types of Egyptian building materials from various locations in Cairo and its suburbs have been analysed for natural radioactivity using gamma ray spectrometry. Concentrations of (226)Ra, (232)Th and (40)K were in the ranges of (12 +/- 2.8-65 +/- 6.5), (5 +/- 1.8-60 +/- 6.7) and (159 +/- 3.8-920 +/- 12.7 Bq kg(-1)), respectively. The minimum concentration of (226)Ra, (232)Th and (40)K was found in gravel samples, whereas the maximum in granite samples. The results are compared with the published data of other countries and with the world average limits. The radiological hazard parameters: radium equivalent activity, gamma index, alpha index, absorbed dose rate and the annual exposure rate, were determined to assess the radiation hazards associated with Egyptian buildings. All studied samples are lower than world average limits.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. Natural radioactive nuclides and chemical components in the groundwater of Beni Suef Governate, Middle Egypt.

    PubMed

    Khalil, F A; Amin, Rafat M; El Fayoumi, M A K

    2009-03-01

    Measurements of natural radioactivity in drinking water have been performed in many parts of the world, mostly for assessment of the doses and risk resulting from consuming water. A study of the radionuclide and chemical components in groundwater from Beni Suef Governate, Egypt has been carried out. Fifty water samples were analysed by gamma-ray spectroscopy to determine the (226)Ra, (232)Th and (40)K concentrations; major elements, pH, alkalinity and conductivity were also measured. The activity concentration values ranged from 0.008 to 0.040 Bq l(-1) for (226)Ra, from 0.003 to 0.019 Bq l(-1) for (232)Th and from 0.025 to 0.344 Bq l(-1) for (40)K. The annual ingestion of these radionuclides, using local consumption rates (averaged over the whole population) of 1.5 l d(-1), was estimated to be 8.59, 4.86 and 83.47 Bq y(-1) for (226)Ra, (232)Th and (40)K, respectively. The estimated effective doses from drinking water were found to be 2.4 microSv y(-1) ((226)Ra), 1.1 microSv y(-1) ((232)Th) and 0.5 microSv y(-1) ((40)K). The contribution of these radionuclides to the committed effective dose from a year's consumption of drinking water is therefore estimated to be only 4% of the WHO value (0.1 mSv y(-1)). The moderate pH value is the most important parameter, and there was no observed correlation between natural radioactivity and electrical conductivity or concentrations of major ions.

  16. 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.

  17. 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.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    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.

  18. 228Ra/226Ra ratio and 7Be concentration in the Sea of Japan as indicators for water transport: comparison with migration pattern of Fukushima Dai-ichi NPP-derived 134Cs and 137Cs.

    PubMed

    Inoue, M; Furusawa, Y; Fujimoto, K; Minakawa, M; Kofuji, H; Nagao, S; Yamamoto, M; Hamajima, Y; Yoshida, K; Nakano, Y; Hayakawa, K; Oikawa, S; Misonoo, J; Isoda, Y

    2013-12-01

    To assess the migration patterns of radiocesium emitted from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), we analyzed (228)Ra/(226)Ra ratios and (7)Be concentrations and compared them with (134)Cs and (137)Cs concentrations in seawater samples collected within the Sea of Japan before and after the FDNPP accident (i.e., during the period 2007-2012) using low-background γ-spectrometry. The (228)Ra/(226)Ra ratios in surface waters exhibited lateral and seasonal variations, reflecting the flow patterns of surface water. This indicates the transport patterns of the FDNPP-derived radiocesium by surface water. Cosmogenic (7)Be (half-life: 53.3 d) exhibited markedly high concentrations (5-10 mBq/L) at depths shallower than 50 m, with concentrations decreasing steeply (0.2-2 mBq/L) at depths of 50-250 m. The distribution of (7)Be concentrations suggests that the downward delivery of the FDNPP-derived radiocesium to below 50 m depth was negligible for a few months prior to its removal from the Sea of Japan.

  19. Occurrence of natural radioactivity in public water supplies in Germany: (238)U, (234)U, (235)U, (228)RA, (226)RA, (222)RN, (210)PB, (210)PO and gross alpha activity concentrations.

    PubMed

    Beyermann, M; Bünger, T; Schmidt, K; Obrikat, D

    2010-09-01

    The Federal Office for Radiation Protection performed a representative survey on the radiological quality of drinking water in Germany. The aim of this study was to determine regional variations of natural radionuclide concentrations and to estimate radiation exposures caused by drinking water consumption. The study includes analyses of the natural radionuclides (238)U, (234)U, (235)U, (228)Ra, (226)Ra, (222)Rn, (210)Pb, (210)Po and of gross alpha activity concentrations in drinking water from 564 public water supplies. This represents 3 % of all German water supplies providing about 37 Mio. inhabitants. Results on ranges, medians and distributions of radionuclide concentrations of drinking water as well as age-dependent ingestion and inhalation doses estimated for members of the public are presented. Generally, the dose due to uranium isotopes is negligibly low. Radiation exposures are predominantly caused by (222)Rn, (228)Ra, (210)Po and (210)Pb. The ingestion dose deduced for adults (>17 a) and infants (0-1 a) is dominated by (222)Rn and (228)Ra, respectively. A gross alpha activity analysis procedure using liquid scintillation counting has been tested. Measured gross alpha activities values were found to be well related to the summarised activities of (238)U, (234)U, (226)Ra and (210)Po.

  20. 228Ra, 226Ra, 224Ra and 223Ra in potential sources and sinks of land-derived material in the German Bight of the North Sea: implications for the use of radium as a tracer

    NASA Astrophysics Data System (ADS)

    Schmidt, Caroline; Hanfland, Claudia; Regnier, Pierre; van Cappellen, Philippe; Schlüter, Michael; Knauthe, Ulrich; Stimac, Ingrid; Geibert, Walter

    2011-08-01

    Activities of the naturally occurring radium nuclides 228Ra, 226Ra, 224Ra and 223Ra were determined in waters of the open German Bight and adjacent nearshore areas in the North Sea, in order to explore the potential use of radium isotopes as natural tracers of land-ocean interaction in an environment characterised by extensive tidal flats, as well as riverine and groundwater influx. Data collected at various tidal phases from the Weser Estuary (228Ra: 46.3 ± 4.6; 226Ra: 17.1 ± 1.1; 224Ra: 26.1 ± 8.2 to 36.5 ± 6.1; 223Ra: 1.8 ± 0.1 to 4.0 ± 0.4), tidal flats near Sahlenburg (228Ra: 39.3 ± 3.8 to 46.0 ± 4.5; 226Ra: 15.5 ± 1.5 to 16.5 ± 1.7; 224Ra: 34.3 ± 2.2 to 85.3 ± 6.3; 223Ra: 3.6 ± 0.5 to 8.0 ± 1.2), freshwater seeps on tidal flats near Sahlenburg (228Ra: 42.1 ± 4.1; 226Ra: 21.3 ± 2.2; 224Ra: 5.1 ± 0.9; 223Ra: 2.6 ± 1.3) and also in permanently inundated parts of the North Sea (228Ra: 23.0 ± 2.3 to 28.2 ± 2.8; 226Ra: 8.2 ± 0.8 to 11.8 ± 1.2; 224Ra: 3.1 ± 1.0 to 10.1 ± 0.9; 223Ra: 0.1 ± 0.02 to 0.9 ± 0.05; units: disintegrations per minute per 100 kg water sample) reveal that, except for the fresh groundwater, the potential end-members of nearshore water mass mixing have quite similar radium signatures, excluding a simple discrimination between the sources. However, the decreasing activities of the short-lived 224Ra and 223Ra isotopes recorded towards the island of Helgoland in the central German Bight show a potential to constrain fluxes of land-derived material to the open North Sea. The largest source for all radium isotopes is generally found on the vast tidal flats and in the Weser Estuary. Future work could meaningfully combine this so-called radium quartet approach with investigations of radon activity. Indeed, preliminary data from a tidal flat site with fresh groundwater seepage reveal a 222Rn signal that is clearly lower in seawater.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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).

  9. Fission and binary fragmentation reactions in {sup 80}Se+{sup 208}Pb and {sup 80}Se+{sup 232}Th systems

    SciTech Connect

    Thomas, R. G.; Saxena, A.; Sahu, P. K.; Kailas, S.; Kapoor, S. S.; Choudhury, R. K.; Govil, I. M.; Barbui, M.; Cinausero, M.; Prete, G.; Rizzi, V.; Fabris, D.; Lunardon, M.; Moretto, S.; Viesti, G.; Nebbia, G.; Pesente, S.; Dalena, B.; D'Erasmo, G.; Fiore, E. M.

    2007-02-15

    Fission and binary fragmentation of the excited nuclear systems of Z=116 and 124 were investigated using the reactions induced by {sup 80}Se beams on {sup 208}Pb and {sup 232}Th targets at bombarding energies ranging from 470 to 630 MeV. The mass and kinetic energy of the binary reaction products were reconstructed by measuring their velocities by the time-of-flight method and the angles of emission using multiwire proportional chambers. Total neutron multiplicities were measured in coincidence with the fragments, using an array of neutron detectors. The fragment mass-energy correlation was studied for the two systems. The average total kinetic energy (TKE) of fragments for the {sup 80}Se+{sup 208}Pb system agrees with earlier measurements and with Viola's systematics in the mass symmetric region for compound nucleus fission, whereas for the {sup 80}Se+{sup 232}Th system, the TKE values are significantly lower. This is also consistent with higher values of total neutron multiplicities observed for the case of {sup 80}Se+{sup 232}Th at comparable available energies. From an extrapolation of the measured total neutron multiplicities for the mass symmetric region to zero compound nucleus excitation energy, the average number of prompt neutrons expected to be emitted in the spontaneous fission of the superheavy Z=116 has been estimated to be {nu}{sub tot}{sup sf}=10{+-}2, which is consistent with the value derived for the same compound nucleus populated in the {sup 56}Fe+{sup 232}Th reaction in an earlier work. In the case of the {sup 80}Se+{sup 232}Th system, similar analysis was carried out by taking the average TKE from Viola's systematics for estimating the available energy for particle emission corresponding to compound nucleus fission. In this way, by extrapolating the observed neutron multiplicities to zero compound nucleus excitation energy, a value of {nu}{sub tot}{sup sf}=15{+-}2 was obtained for the spontaneous fission of the superheavy Z=124 nucleus. The

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Natural radionuclide activities in forest soil horizons of Mount IDA/Kazdagi, Turkey.

    PubMed

    Karadeniz, Özlem; Karakurt, Hidayet; Akal, Cüneyt

    2015-06-01

    Natural radioactivity distribution of (40)K, (238)U, and (232)Th isotopes in forest soils was investigated by using gamma-ray spectrometry. An extensive radioecological study was carried out between 2010 and 2013 in Mount IDA/Kazdagi, located in Edremit region in Turkey. A total of 341 soil samples were collected from the surface and organic horizons (OL, OF+OH, and A) in 118 soil profiles. The distributions of natural radioactivity levels in these horizons and corresponding absorbed dose rates from outdoors terrestrial gamma radiation throughout the region were mapped in detail. Mean (40)K activity values over the combined horizons varied between 43 and 1,008 Bq kg(-1); whereas, mean (226)Ra and (232)Th concentrations over the combined horizons ranged between 5-152 and 6-275 Bq kg(-1), respectively. Our data indicate that the radioactivity values of the study sites were within the universal normal range. The significant variation among the (232)Th, (226)Ra, and (40)K activities and gamma dose rate might be due to the geological variation in the study sites.

  20. Determination of the 233Pa(n, f) reaction cross section from 0.5 to 10 MeV neutron energy using the transfer reaction 232Th( 3He, p) 234Pa

    NASA Astrophysics Data System (ADS)

    Petit, M.; Aiche, M.; Barreau, G.; Boyer, S.; Carjan, N.; Czajkowski, S.; Dassié, D.; Grosjean, C.; Guiral, A.; Haas, B.; Karamanis, D.; Misicu, S.; Rizea, C.; Saintamon, F.; Andriamonje, S.; Bouchez, E.; Gunsing, F.; Hurstel, A.; Lecoz, Y.; Lucas, R.; Theisen, Ch.; Billebaud, A.; Perrot, L.; Bauge, E.

    2004-05-01

    The fission probability distributions of 232, 233, 234 Pa and 231Th have been measured up to an excitation energy of 15 MeV, using the transfer reactions 232Th( 3He, t) 232Pa, 232Th( 3He, d) 233Pa, 232Th( 3He, p) 234Pa and 232Th( 3He, 4He) 231Th. From these measurements, the neutron induced fission cross sections of 231Pa, 233Pa and 230Th have been determined from the product of the fission probabilities of 232Pa, 233Pa and 231Th respectively with the calculated compound nucleus formation cross sections in the 231Pa+n, 233Pa+n and 230Th+n reactions. The validity of the applied method has been successfully tested with the existing neutron induced fission cross sections of 230Th and 231Pa. Special emphasis is put on the 233Pa(n, f) reaction which is of importance for thorium fueled nuclear reactors. Based on a statistical model analysis of the neutron induced fission cross section as a function of neutron energy, it has been possible to determine the barrier parameters of the 234Pa fissioning nucleus. Cross sections for the compound nucleus inelastic scatttering 233Pa(n, n') and radiative capture 233Pa(n, γ) reactions have also been calculated and compared with recent evaluations.

  1. 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

  2. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters.

    PubMed

    Singh, S K; Dalai, Tarun K; Krishnaswami, S

    2003-01-01

    238U and (232)Th concentrations and the extent of (238)U-(234)U-(230)Th radioactive equilibrium have been measured in a suite of Precambrian carbonates and black shales from the Lesser Himalaya. These measurements were made to determine their abundances in these deposits, their contributions to dissolved uranium budget of the headwaters of the Ganga and the Indus in the Himalaya and to assess the impact of weathering on (238)U-(234)U-(230)Th radioactive equilibrium in them. (238)U concentrations in Precambrian carbonates range from 0.06 to 2.07 microg g(-1). The 'mean' U/Ca in these carbonates is 2.9 ng U mg(-1) Ca. This ratio, coupled with the assumption that all Ca in the Ganga-Indus headwaters is of carbonate origin and that U and Ca behave conservatively in rivers after their release from carbonates, provides an upper limit on the U contribution from these carbonates, to be a few percent of dissolved uranium in rivers. There are, however, a few streams with low uranium concentrations, for which the carbonate contribution could be much higher. These results suggest that Precambrian carbonates make only minor contributions to the uranium budget of the Ganga-Indus headwaters in the Himalaya on a basin wide scale, however, they could be important for particular streams. Similar estimates of silicate contribution to uranium budget of these rivers using U/Na in silicates and Na* (Na corrected for cyclic and halite contributions) in river waters show that silicates can contribute significantly (approximately 40% on average) to their U balance. If, however, much of the uranium in these silicates is associated with weathering resistant minerals, then the estimated silicate uranium component would be upper limits. Uranium concentration in black shales averages about 37 microg g(-1). Based on this concentration, supply of U from at least approximately 50 mg of black shales per liter of river water is needed to balance the average river water U concentration, 1.7 microg L

  3. The natural radioactivity in Guarani aquifer groundwater, Brazil.

    PubMed

    Bonotto, D M; Bueno, T O

    2008-10-01

    The measurements of gross alpha and gross beta radioactivity in groundwater samples from Guarani aquifer in Brazil are reported in this paper together with the activity concentration of the natural dissolved radionuclides (40)K, (238)U, (234)U, (226)Ra, (222)Rn, (210)Po, (210)Pb, (232)Th, (228Th), and (228)Ra. Most of the gross alpha radioactivity values were below the critical level of detection corresponding to 1 mBq/L, however, the whole data set for the gross beta radioactivity and radionuclides (40)K, (238)U, (234)U, (226)Ra, (222)Rn, (210)Po, (210)Pb, and (228)Ra was submitted to a statistical treatment, considering class intervals arranged in geometric progression, because of the great variability of the activity. The analysis indicated lognormal distribution of the data, as usually observed in samples taken from the natural context. An inverse relationship between the gross alpha and gross beta activity has been identified and is related to an increase in the K content in the water. The mobility coefficient has been estimated for (238)U, (226)Ra, (232)Th and (228)Ra in Guarani aquifer and the results indicated that the radioelement solubility in the studied system varies according to the following order: radium>uranium>thorium. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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).

  12. 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 PAGES

    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.

  13. 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

  14. 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.

  15. 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).

  16. 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

  17. 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.

  18. Assessment of natural radioactivity in aquifer medium bearing uranium ores in Koprubasi, Turkey

    NASA Astrophysics Data System (ADS)

    Simsek, Celalettin

    2008-10-01

    Koprubasi, located within Manisa Province near the Izmir, is the biggest uranium mine where uranium ores originate from Neogene aged altered sandstone and conglomerate layers. The main objective of this study is to determine the radiation hazard associated with radioactivity levels of uranium ores, and the rocks and sediments around Koprubasi. In this regard, measured activity levels of 226Ra, 232Th and 40K were compared with world averages. The average activity levels of 226 Ra, 232Th and 40K were measured to be 5369.75, 124.78 and 10.0 Bq/kg in uranium ores, 24.32, 52.94 and 623.38 Bq/kg in gneiss, 46.24, 45.13 and 762.26 Bq/kg in sandstone and conglomerate, 73.11, 43.15 and 810.65 Bq/kg in sediments, respectively. All samples have high 226Ra and 40K levels according to world average level. As these sediments are used as construction materials and in agricultural activities within the study area, the radiation hazard are calculated by using dose rate (D), annual effective dose rate (He), radium equivalent activity (Raeq) and radiation hazard index (Iyr). All the samples have Raeq levels that are lower than the world average limit of 370 Bq/kg. On the other hand, D, He and Iyr values are higher than world average values. These results indicate that the uranium ores in the Koprubasi is the most important contributor to the natural radiation level. The radioactivity levels of sediments and rocks make them unsuitable for use as agricultural soil and as construction materials. Moreover, it is determined that shallow groundwater in sediments and deep groundwater in conglomerate rocks and also surface water sources in the Koprubasi have high 226Ra content. According to environmental radioactive baseline, some environmental protection study must be taken in Koprubasi uranium site and the environment.

  19. 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

  20. 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.

  1. Natural radioactivity in and radon exhalation from Finnish building materials.

    PubMed

    Mustonen, R

    1984-06-01

    A total of 369 samples of Finnish building materials were tested for their 226Ra, 232Th and 40K concentrations. The rate of radon exhalation was measured from 19 samples of material and 34 dwellings were tested for their room air ventilation rate and radon concentration. The mean values of 226Ra, 232Th and 40K concentrations in ballast materials for concrete production were 34.2 Bq X kg-1, 39.0 Bq X kg-1 and 964 Bq X kg-1, with standard deviations of 18.7 Bq X kg-1, 19.5 Bq X kg-1 and 265 Bq X kg-1, respectively. The activity concentrations were higher in clay bricks than in concrete, the mean values being 79.8 Bq X kg-1, 61.6 Bq X kg-1 and 986 Bq X kg-1 for 226Ra, 232Th and 40K, respectively. The normalized radon exhalation rates from 15-cm-thick concrete, slag-aggregate concrete and by-product gypsum were 0.38 (Bq X m-2 X h-1)/(Bq X kg-1), 0.15 (Bq X m-2 X h-1)/(Bq X kg-1), and 0.06 (Bq X m-2 X h-1)/(Bq X kg-1), respectively. The ventilation rates in dwellings varied between 0.27 and 1.99 air changes per h, the mean value being 0.60 h-1, and the corresponding steady state radon concentrations in room air varied from 17.0 to 149 Bq X m-3 in blocks of flats made of concrete and from 11.2 to 61.9 Bq X m-3 in blocks of flats made of brick.

  2. 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

  3. 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

  4. 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.

  5. 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

  6. Natural radioactivity levels and heavy metals in chemical and organic fertilizers used in Kingdom of Saudi Arabia.

    PubMed

    El-Taher, A; Althoyaib, S S

    2012-01-01

    The present work deals with identifying and determining the activity levels of natural occuring radionuclides, (226)Ra and (232)Th series, their decay products and (40)K, in chemical and organic fertilizers used in Kingdom of Saudi Arabia. A total of 30 samples: 20 phosphatic fertilizers (single super-phosphate SSP and triple super-phosphate,TSP) and 10 organic fertilizers (cow, sheep and chicken) collected from markets and farms. The gamma-ray spectrometer consists of NaI(Tl) detector and its electronic circuit was used for measuring γ-ray spectra. The ranges of radioactivity levels of (226)Ra, (232)Th and (40)K in chemical fertilizers are 51.5±5.2-106.3±7.5, 5.1±1.6-9.9±3.2. and 462.6±21-607.3±14Bqkg(-1), respectively. The activities of (226)Ra, (232)Th and (40)K in natural fertilizers (cow, sheep and chicken) are lower than the activities in chemical fertilizers. The obtained data are compared with available reported data from other countries in literature. The Ra(eq) in chemical fertilizer ranges from 100.37 to 161.43Bqkg(-1) and in organic fertilizer ranges from 34.07 to 102.19Bqkg(-1), which are lower than the limit of 370Bqkg(-1) adopted from NEA-OECD (1979). The average heavy metal (Pb, Cd, Ni, Co and Cr) contents of the fertilizers marketed in the Kingdom of Saudi Arabia are also determined and within the limits of those used worldwide.

  7. 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.

  8. Natural radioactivity measurements in building materials used in Samsun, Turkey.

    PubMed

    Tufan, M Çagatay; Disci, Tugba

    2013-01-01

    In this study, radioactivity levels of 35 different samples of 11 commonly used building materials in Samsun were measured by using a gamma spectrometry system. The analysis carried out with the high purity Germanium gamma spectrometry system. Radioactivity concentrations of (226)Ra, (232)Th and (40)K range from 6 to 54 Bq kg(-1), 5 to 88 Bq kg(-1) and 6 to 1070 Bq kg(-1), respectively. From these results, radium equivalent activities, gamma indexes, absorbed dose rates and annual effective doses were calculated for all samples. Obtained results were compared with the available data, and it was concluded that all the investigated materials did not have radiological risk.

  9. Occupational exposure due to naturally occurring radionuclide material in granite quarry industry.

    PubMed

    Ademola, J A

    2012-02-01

    The potential occupational exposure in granite quarry industry due to the presence of naturally occurring radioactive material (NORM) has been investigated. The activity concentrations of (40)K, (226)Ra and (232)Th were determined using gamma-ray spectroscopy method. The annual effective dose of workers through different exposure pathways was determined by model calculations. The total annual effective dose varied from 21.48 to 33.69 μSv y(-1). Inhalation dose contributes the highest to the total effective dose. The results obtained were much lower than the intervention exemption levels (1.0 mSv y(-1)) given in the International Commission on Radiological Protection Publication 82.

  10. 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.

  11. Determination of radioactivity and heavy metals of Bakirçay river in Western Turkey.

    PubMed

    Saç, M M; Ortabuk, F; Kumru, M N; Içhedef, M; Sert, S

    2012-10-01

    In this study, radioactive and heavy metal contaminations in sediments and waters of Bakırçay River in Western Turkey were investigated to determine their pollution potential. The radium concentrations in the water samples were measured using the collector-chamber method. The radioactivities of (40)K, (226)Ra and (232)Th in sediments and soils were found to be 45.30 to 839.19 Bq kg(-1), 35.26 to 160.57 Bq kg(-1) and 1.86 to 131.49 Bq kg(-1), respectively. The activity of (226)Ra in the water samples ranged from 0.09 to 0.36 Bq/L. To determine the radiological hazard of natural radioactivity in the samples, the external terrestrial gamma dose rate in air (n Gyh(-1)), annual effective dose rate (mSv y(-1)), radium equivalent activity (Bq kg(-1)) were calculated and compared with internationally recommended values.

  12. The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area, Sinai, Egypt.

    PubMed

    Nada, A; Aly, H A S

    2014-02-01

    The concentrations and distributions of the activity of natural radionuclides in soil samples were investigated in fifteen soil samples at El-Gor area representing two profiles (A and B) using a HP-Ge detector and alpha counting by SSNTD (CR-39), respectively. The average concentrations of the radionuclides (238)U, (226)Ra, (235)U, (232)Th and (40)K are 203.4, 177.23, 9.77, 43.33 and 386.22 Bq kg(-1) (dry weight), respectively, and profile A and (238)U, (226)Ra, (235)U, (232)Th and (40)K have average concentrations of 232.58, 246, 11.7, 31.7, and 277.07 Bq kg(-1) for profile B, respectively. The eTh and eU were estimated to detect the migration process of uranium into or out of an area or uranium to or from the studied profiles. The results indicate a migration of uranium by 29% for profile A and 65.37% for profile B. The activity ratio ((238)U/(226)Ra) was found to be 0.9 in profile A and 1.15 in profile B. These ratios coincide with the uranium migration processes. The responsible mass corresponding to the measured (226)Ra activity was also calculated. The radon activity concentrations for the two profiles are nearly 300 Bq m(-3). The emanation coefficient (η) was calculated from the ratio of the expected radon activity to the measured radon for the studied soil samples. The value of η was found to depend only on the radium activity regardless to soil formation.

  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. Daily intakes of naturally occurring radioisotopes in typical Korean foods.

    PubMed

    Choi, Min-Seok; Lin, Xiu-Jing; Lee, Sun Ah; Kim, Wan; Kang, Hee-Dong; Doh, Sih-Hong; Kim, Do-Sung; Lee, Dong-Myung

    2008-08-01

    The concentrations of naturally occurring radioisotopes ((232)Th, (228)Th, (230)Th, (228)Ra, (226)Ra, and (40)K) in typical Korean foods were evaluated. The daily intakes of these radioisotopes were calculated by comparing concentrations in typical Korean foods and the daily consumption rates of these foods. Daily intakes were as follows: (232)Th, 0.00-0.23; (228)Th, 0.00-2.04; (230)Th, 0.00-0.26; (228)Ra, 0.02-2.73; (226)Ra, 0.01-4.37 mBq/day; and (40)K, 0.01-5.71 Bq/day. The total daily intake of the naturally occurring radioisotopes measured in this study from food was 39.46 Bq/day. The total annual internal dose resulting from ingestion of radioisotopes in food was 109.83 muSv/y, and the radioisotope with the highest daily intake was (40)K. These values were same level compiled in other countries.

  15. Radiological impacts of natural radioactivity in Abu-Tartor phosphate deposits, Egypt.

    PubMed

    Khater, A E; Higgy, R H; Pimpl, M

    2001-01-01

    Phosphate and environmental samples were collected from Abu Tartor phosphate mine and the surrounding region. The activity concentration of 226Ra (238U) series, 232Th series and 40K were measured using a gamma-ray spectrometer. The activities of uranium isotopes (238U, 235U and 234U) and 210Pb were measured using an alpha spectrometer and a low-background proportional gas counting system, respectively, after radiochemical separation. The results are discussed and compared with the levels in phosphate rocks from different countries. It seems that the Abu Tartor phosphate deposit has the lowest radioactivity level of exploited phosphate of sedimentary origin. 226Ra/238U, 210Pb/226Ra, 234U/238U and 226Ra/228Ra activity ratios were calculated and are discussed. The radioactivity levels in the surrounding region and the calculated exposure dose (nGy/h) will be considered as a pre-operational baseline to estimate the possible radiological impacts due to mining, processing and future phosphate industrial activities. To minimize these impacts, the processing wastes should be recycled to the greatest possible extent.

  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. 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.

  18. Investigation of background radiation levels and geologic unit profiles in Durango, Colorado

    SciTech Connect

    Triplett, G.H. ); Foutz, W.L.; Lesperance, L.R. )

    1989-11-01

    As part of the Uranium Mill Tailings Remedial Action (UMTRA) Project, Oak Ridge National Laboratory (ORNL) has performed radiological surveys on 435 vicinity properties (VPs) in the Durango area. This study was undertaken to establish the background radiation levels and geologic unit profiles in the Durango VP area. During the months of May through June, 1986, extensive radiometric measurements and surface soil samples were collected in the Durango VP area by personnel from ORNL's Grand Junction Office. A majority of the Durango VP surveys were conducted at sites underlain by Quaternary alluvium, older Quaternary gravels, and Cretaceous Lewis and Mancos shales. These four geologic units were selected to be evaluated. The data indicated no formation anomalies and established regional background radiation levels. Durango background radionuclide concentrations in surface soil were determined to be 20.3 {plus minus} 3.4 pCi/g for {sup 40}K, 1.6 {plus minus} 0.5 pCi/g for {sup 226}Ra, and 1.2 {plus minus} 0.3 pCi/g for {sup 232}Th. The Durango background gamma exposure rate was found to be 16.5 {plus minus} 1.3 {mu}R/h. Average gamma spectral count rate measurements for {sup 40}K, {sup 226}Ra and {sup 232}Th were determined to be 553, 150, and 98 counts per minute (cpm), respectively. Geologic unit profiles and Durango background radiation measurements are presented and compared with other areas. 19 refs., 15 figs., 5 tabs.

  19. 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.

  20. 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.

  1. Measurement of natural radioactivity in Jordanian building materials and their contribution to the public indoor gamma dose rate.

    PubMed

    Sharaf, J M; Hamideen, M S

    2013-10-01

    This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of (226)Ra, (232)Th, and (40)K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan. PMID:23831927

  2. Quantitative measurement of natural radioactivity in some roofing tile materials used in upper Egypt.

    PubMed

    Uosif, M A M

    2013-09-01

    The quantitative measurement of radionuclides ((226)Ra, (232)Th and (40)K) in some roofing tile materials (granite, alabaster, marble, traditional and advanced ceramic) used in Upper Egypt is presented in this paper. Measurements were done by using gamma spectrometry (NaI (Tl) 3" × 3"). The values of concentration of natural radionuclides were in the following ranges: 12-78.9 Bq kg(-1) for (226)Ra, 8.4-113.1 Bq kg(-1) for (232)Th and 94.9-509 Bq kg(-1)for (40)K. The activity concentration index (I), the specific dose rates indoors ( ) and the annual effective dose (DE) due to gamma radiation were calculated for each investigated sample. The lowest value of I is 0.19 for alabaster, while the highest one is 0.88 for traditional and advanced ceramic. The ranges of DE are between 0.03 and 0.13 mSv, it is below the maximal permitted values, so that the examined materials could be used as roofing tiles in the construction of new buildings. PMID:23516266

  3. 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 %.

  4. 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.

  5. Measurement of natural radioactivity in building materials in Qena city, Upper Egypt.

    PubMed

    Ahmed, Nour Khalifa

    2005-01-01

    Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials (bricks, cement, gypsum, ceramics, marble, limestone and granite) in Qena city, Upper Egypt have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. The results show that the highest mean value of (226)Ra activity is 205+/-83 Bqkg(-1) measured in marble. The corresponding value of (232)Th is 118+/-14 Bqkg(-1) measured in granite. For (40)K this value is (8.7+/-3.9)x10(2) Bqkg(-1) measured in marble. The average concentrations of the three radionuclides in the different building materials are 116+/-54, 64+/-34 and (4.8+/-2.2)x10(2) Bqkg(-1) for (226)Ra, (232)Th and (40)K, respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The maximum mean of radium equivalent activity Ra(eq) is 436+/-199 Bqkg(-1) calculated in marble. The highest radioactivity level and dose rate in air from these materials were calculated in marble.

  6. Measurement of natural radioactivity in Jordanian building materials and their contribution to the public indoor gamma dose rate.

    PubMed

    Sharaf, J M; Hamideen, M S

    2013-10-01

    This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of (226)Ra, (232)Th, and (40)K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan.

  7. Assessment of natural radioactivity in commercial granites used in Turkey.

    PubMed

    Onargan, Turgay; Gür, Filiz; Kaya, Erol; Güneri, Sinem

    2012-01-01

    The activity concentrations of (226)Ra, (232)Th and (40)K in twelve different domestic and imported tiling rocks (granites) used as building materials in Turkey were determined by employing high-resolution γ-ray spectrometry. The samples were evaluated to assess the radiation hazard for people by comparing the results with the control values recommended by the European Commission. The measured activity concentrations ranged from 7 to 136 Bq kg(-1), 9 to 138 Bq kg(-1) and 541 to 1277 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. Applying dose criteria recommended by the European Commission([15]), two of the samples showed higher Ra(eq) values than the limit dose of 370 Bq kg(-1), equivalent to a γ-dose of 1.5 mSv y(-1). The calculated gamma-index (I(γ)) values for all the 12 samples were lower than the recommended dose criterion. In some of the samples; however, the H(ex) and H(in) values were more than unity. The absorbed dose rates (D) for all the samples, except for four samples, were located within the range values recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)([3]). Annual effective dose (AED) values, except for one sample, were greater than the world average value of UNSCEAR([3]).

  8. Norm and associated radiation hazards in bricks fabricated in various localities of the North-West Frontier Province (Pakistan).

    PubMed

    Khan, Khalid; Aslam, M; Orfi, S D; Khan, H M

    2002-01-01

    The activity concentrations of natural gamma-emitting radionuclides and associated radiation hazards due to 40K, 226Ra and 232Th have been measured in baked brick samples, collected from six highly populated areas of the North-West Frontier Province (NWFP) of Pakistan. For the detection, analysis and data acquisition, a high purity germanium (HPGe) detector coupled with a high resolution multichannel analyser (MCA) was used. The range of the average values of the activity concentrations due to 40K, 226Ra and 232Th were found to be 680.3 +/- 22.2-784.4 +/- 30.7 Bq kg(-1), 36.9 +/- 3.5-51.9 +/- 3.3 Bq kg(-1) and 52.5 +/- 3.6-67.6 +/- 3.1 Bq kg(-1), respectively. Radium equivalent (Ra(eq)) activities and various hazard indices were also calculated to assess the radiation hazards. All the brick samples showed Ra, activities within the limit (370 Bq kg(-1)) set by the Organization for Economic Cooperation and Development (OECD) countries. The results of different criterion formulae also complemented each other in this study. The derived data have been compared with the reported values for other countries of the world.

  9. 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.

  10. 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.

  11. 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.

  12. Measurement of soil radioactivity levels and radiation hazard assessment in southern Rechna interfluvial region, Pakistan.

    PubMed

    Jabbar, Abdul; Arshed, Waheed; Bhatti, Arshad Saleem; Ahmad, Syed Salman; Akhter, Perveen; Rehman, Saeed-Ur; Anjum, Muhammad Iftikhar

    2010-10-01

    Rechna interfluvial region is one of the main regions of Punjab, Pakistan. It is the area which is lying between River Ravi and River Chenab, alluvial-filled. Radioactivity levels in soil samples, collected from southern Rechna interfluvial region, Pakistan, have been estimated by using gamma-ray spectrometric technique. (226)Ra, (232)Th, the primordial radionuclide (40)K, and the artificial radionuclide (137)Cs have been measured in the soil of the study area. The mean radioactivity levels of (226)Ra, (232)Th, (40)K, and (137)Cs were found to be 50.6 +/- 1.7, 62.3 +/- 3.2, 662.2 +/- 32.1, and 3.1 +/- 0.3 Bq kg(-1), respectively. The mean radium equivalent activity (Ra(eq)), outdoor radiation hazard index (H(out)), indoor radiation hazard index (H(in)), and terrestrial absorbed dose rate for the area under study were determined as 190.8 +/- 8.7 Bq kg(-1), 0.52, 0.65, and 69.8 nGy h(-1), respectively. The annual effective dose to the general public was found to be 0.43 mSv. This value lies well below the limit of 1 mSv for general public as recommended by the International Commission on Radiological Protection. The measured values are comparable with other global radioactivity measurements and are found to be safe for the public and the environment.

  13. Terrestrial radioactivity of the Jabal Eghei area in southern Libya and assessment of the associated environmental risks.

    PubMed

    Tereesh, Mehdi Bashir; Radenkovic, Mirjana B; Kovacevic, Jovan; Miljanic, Scepan S

    2013-01-01

    Activity concentrations of main terrestrial radioisotopes (226)Ra, (232)Th and (40)K were measured in geological samples collected in Libya's Jabal Eghei area, in order to contribute to the establishment of a baseline map of the environmental radioactivity levels and to estimate the associated environmental risk to the population. Activity concentrations ranged from 22 to 5256 Bq kg(-1) for (226)Ra, from 11 to 221 Bq kg(-1) for (232)Th and from 132.0 to 2304 Bq kg(-1) for (40)K. Using these results, representative risk factors were calculated: the total absorbed gamma dose rate in air (ranged from 25.5 to 2434.3 nGy h(-1) with a mean value of 251.8 nGy h(-1)), the radium equivalent activity (55-5281 Bq kg(-1), with the mean value of 537 Bq kg(-1)), external hazard index (0.149-14.24, with a mean value of 1.451) and annual outdoor effective dose (31.3-2985.4 μSv, with a mean value of 308.9 μSv). Accordingly, the radiation risk is above the world average, mainly as the consequence of discovered uranium anomalies.

  14. Estimation of radioactivity level and associated radiological hazards of limestone and gypsum used as raw building materials in Rawalpindi/Islamabad region of Pakistan.

    PubMed

    Gul, Rahmat; Ali, Safdar; Hussain, Manzur

    2014-01-01

    This study was undertaken to asses the radioactivity level of limestone and gypsum and its associated radiological hazard due to the presence of naturally occurring radioactive materials. Representative samples of limestone and gypsum were collected from cement factories located in the Rawalpindi/Islamabad region of Pakistan and were analysed by using an N-type high-purity germanium detector of 80 % relative efficiency. The average activity concentration of (40)K, (226)Ra and (232)Th were 60.22±3.47, 29.25±5.23 and 4.07±3.31 Bq kg(-1), respectively, in limestone and 70.86±4.1, 5.01±2.10 and 4.49±3.1 Bq kg(-1), respectively, in gypsum. The radiological hazard parameters radium equivalent activities, absorbed dose rate in air, external hazard index, internal hazard index, annual effective dose equivalent, gamma index and alpha index were computed. The results of the average activity concentrations of (40)K, (226)Ra and (232)Th and radiological hazard parameters were within the range of the reported average worldwide/United Nations Scientific Committee on the Effect of Atomic Radiation values. It is concluded that limestone and gypsum used in the Rawalpindi/Islamabad region does not pose any excessive radiological health hazard as a building raw materials and in industrial uses.

  15. Assessment of radiological hazard of NORM in Margalla Hills limestone, Pakistan.

    PubMed

    Ali, Muhammad; Qureshi, Aziz Ahmed; Waheed, Abdul; Baloch, Muzahir Ali; Qayyum, Hamza; Tufail, Muhammad; Khan, Hameed Ahmed

    2012-08-01

    Studies on naturally occurring radioactive material (NORM) in the limestone from the Margalla Hills have been carried out by measuring gamma activity and to access its radiological implications if any. For data acquisition, a High-Purity Germanium detector was employed. The activity concentrations of (226)Ra, (232)Th, and (40)K were found to be 14.32 ± 0.24, 2.05 ± 0.04, and 13.80 ± 0.20 Bq kg(-1), respectively. These values are relatively lower as compared to that in the limestone of other countries and much lower than the values reported for the natural building stones. The average specific activities due to (226)Ra were found to be higher when compared with (40)K and (232)Th. Indices of radium equivalent activity (Ra(eq)), internal hazard (H(in)), indoor absorbed gamma dose rate (D(R,)), and corresponding annual effective dose (E(eff)) were also determined for the limestone-made rooms. All of these indices were found to be in the lower ranges. The Margalla Hills limestone does not pose any excessive radiological health hazard as a building material and in industrial uses for a common man.

  16. Radionuclide content of NORM by-products originating from the coal-fired power plant in Oroszlány (Hungary).

    PubMed

    Kardos, R; Sas, Z; Hegedűs, M; Shahrokhi, A; Somlai, J; Kovács, T

    2015-11-01

    At the Thermal Power Plant in Oroszlány (Hungary), a huge amount of by-products have been produced since 1961. In this survey, coal and other by-products were examined (fly ash, bottom ash, fluidised bed bottom ash, gypsum and slurry-type ash). The natural isotopes were determined using an HPGe detector. It was found that the radionuclide content of coal was significantly lower ((226)Ra = 45.3±6.3, (232)Th = 26.3±5.7 and (40)K = 210±21 Bq kg(-1)) than that in the case of ashes other than the fluidised type. The average values of the bottom ash-deposited in the largest quantities-were three times higher than those for coal ((226)Ra = 144±18, (232)Th = 84.3±14 and (40)K = 260±25 Bq kg(-1)). In the case of fractionised bottom ash, the radionuclide content of <0.1 mm was 45 % higher than that of >1.6 mm and the massic radon exhalation of <0.1 mm was approximately four times higher than that above this range.

  17. 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

  18. 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.

  19. Analysis of internal exposure associated with consumption of crops and groundwater from the high background radiation area of Mrima Hill, Kenya.

    PubMed

    Chege, M W; Hashim, N O; Merenga, A S; Tschiersch, J

    2015-11-01

    Specific concentrations of (226)Ra, (232)Th and (40)K were measured in cassava tubers, cassava leaves and groundwater obtained from the high background radiation area of Mrima hill and used in the evaluation of the ingested dose. Cassava tubers, cassava leaves and groundwater registered average (226)Ra concentrations of 60 ± 5, 141 ± 11 and 4.3 ± 0.3 Bq kg(-1), respectively. (232)Th was not detected in cassava leaves although it was present in cassava tubers as well as in groundwater in average concentrations of 35.3±61.5 and 2.0±0.1 Bq kg(-1), respectively. (40)K was present in all samples in average concentrations of 842±539 Bq kg(-1) in cassava tubers, 1708 ± 552 Bq kg(-1) in cassava leaves and 91.4 Bq kg(-1) in groundwater. The total annual effective dose due to ingestion was found to be 7.9 mSv y(-1) of which 2.4 mSv y(-1) was due to cassava tubers, 3.8 mSv y(-1) due to cassava leaves and 1.7 mSv y(-1) due to water.

  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.

  1. Natural radioactivity in granite stones used as building materials in Iran.

    PubMed

    Asgharizadeh, F; Abbasi, A; Hochaghani, O; Gooya, E S

    2012-04-01

    Due to increasing concern about environmental radiological protection, specific radioactivity concentrations of (226)Ra, (232)Th and (40)K in different types of commonly used granite stone samples collected from the Tehran city of Iran have been determined by means of a high-resolution HPGe gamma-spectroscopy system. The activity concentrations of (232)Th, (226)Ra and (40)K in the selected granite samples ranged from 18 to 178, 6 to 160 and 556 to 1539 Bq kg(-1), respectively. The radium equivalent activities (Ra(eq)) are lower than the limit of 370 Bq kg(-1) set by NEA-OECD [Nuclear Energy Agency. Exposure to radiation from natural radioactivity in building materials. Report by NEA Group of Experts. OECD (1979)], except in two samples. The internal hazard indexes have been found well below the acceptable limit in most of the samples. Five samples of investigated commercial granite stones do not satisfy the safety criterion illustrated by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation. Exposure from natural sources of radiation. Report to the General Assembly (1993). Applying dose criteria recently recommended by the EC [European Commission Report on Radiological Protection Principles Concerning the Natural Radioactivity of Building Materials. Radiation Protection 112 (1999)] for superficial materials, all investigated samples meet the exemption dose limit of 0.3 mSv y(-1).

  2. 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.

  3. 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.

  4. Natural radioactivity measurements in rock samples of Cuihua Mountain National Geological Park, China.

    PubMed

    Lu, Xinwei; Zhang, Xiaolan

    2008-01-01

    The concentrations of the natural radionuclides namely 40K, 232Th and 226Ra in rock samples collected from Cuihua Mountain National Geological Park of China have been determined using a NaI(Tl) detector. The concentrations of 226Ra, 232Th and 40K in the studied rock samples range from 10.7 to 34.8, 19.9 to 53.6 and 642.7 to 1609.9 Bq kg(-1) with an average of 20.4, 30.1 and 1009.5 Bq kg(-1), respectively. The concentrations of these radionuclides are compared with the typical world values. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the air absorbed dose rate, the annual effective dose rate, the representative level index and the values of both external and internal hazard indices were evaluated and compared with the internationally approved values. The radium equivalent activity values of all rock samples are lower than the limit of 370 Bq kg(-1). The values of H ex and H in are less than unity. The mean outdoor air absorbed dose rate is 69.7 nGy h(-1), and the corresponding outdoor effective dose rate is 0.086 mSv y(-1).

  5. Measurement of naturally occurring radionuclides in geothermal samples and assessment of radiological risks and radiation doses.

    PubMed

    Parmaksiz, A

    2013-12-01

    The analysis of (226)Ra, (232)Th and (40)K radionuclides has been carried out in geothermal water and residue samples collected from six wells of geothermal power plant and disposal site, using gamma-spectrometry system equipped with a high-purity germanium detector. The activity concentrations of nine geothermal water samples were found to be lower than minimum detectable activity (MDA) values. The activity concentration of the residue samples ranged from 40 ± 4 to 2694 ± 85 Bq kg(-1) for (226)Ra, 33 ± 4 to 2388 ± 85 Bq kg(-1) for (232)Th, and MDA value to 967 ± 30 Bq kg(-1) for (40)K. In the study, some radiological indexes were examined and found to be higher than the reference values for majority of the residue samples. The annual effective doses arising from some residue samples were calculated to be higher than the permitted dose rate for the public, i.e. 1 mSv y(-1).

  6. 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

  7. Quantitative measurement of natural radioactivity in some roofing tile materials used in upper Egypt.

    PubMed

    Uosif, M A M

    2013-09-01

    The quantitative measurement of radionuclides ((226)Ra, (232)Th and (40)K) in some roofing tile materials (granite, alabaster, marble, traditional and advanced ceramic) used in Upper Egypt is presented in this paper. Measurements were done by using gamma spectrometry (NaI (Tl) 3" × 3"). The values of concentration of natural radionuclides were in the following ranges: 12-78.9 Bq kg(-1) for (226)Ra, 8.4-113.1 Bq kg(-1) for (232)Th and 94.9-509 Bq kg(-1)for (40)K. The activity concentration index (I), the specific dose rates indoors ( ) and the annual effective dose (DE) due to gamma radiation were calculated for each investigated sample. The lowest value of I is 0.19 for alabaster, while the highest one is 0.88 for traditional and advanced ceramic. The ranges of DE are between 0.03 and 0.13 mSv, it is below the maximal permitted values, so that the examined materials could be used as roofing tiles in the construction of new buildings.

  8. Radioactivity level in Chinese building ceramic tile.

    PubMed

    Xinwei, L

    2004-01-01

    The activity concentrations of (226)Ra, (232)Th and (40)K have been determined by gamma ray spectrometry. The concentrations of (226)Ra, (232)Th and (40)K range from 158.3 to 1087.6, 91.7 to 1218.4, and 473.8 to 1031.3 Bq kg(-1) for glaze, and from 63.5 to 131.4, 55.4 to 106.5, and 386.7 to 866.8 Bq kg(-1) for ceramic tile, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries and with the typical world values. The radium equivalent activities (Ra(eq)), external hazard index (H(ex)) and internal hazard index (H(in)) associated with the radionuclides were calculated. The Ra(eq) values of all ceramic tiles are lower than the limit of 370 Bq kg(-1). The values of H(ex) and H(in) calculated according to the Chinese criterion for ceramic tiles are less than unity. The Ra(eq) value for the glaze of glazed tile collected from some areas are >370 Bq kg(-1).

  9. Radiological assessment of Abu-Tartur phosphate, Western Desert Egypt.

    PubMed

    Uosif, M A M; El-Taher, A

    2008-01-01

    The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in sedimentary phosphate rock samples (Abu-Tartur phosphate, Western Desert Egypt) by using gamma spectrometry (NaI (Tl) 3"x 3"). Phosphate and environmental samples were collected from Abu-Tartur phosphate mine and the surrounding region. The results are discussed and compared with the levels in phosphate rocks from different countries. The activities of (226)Ra, (232)Th series and (40)K are between (14.9 +/- 0.8 and 302.4 +/- 15.2), (2.6 +/- 1.0 and 154.9 +/- 7.8) and (10.0 +/- 0.5 and 368.4 +/- 18.4) Bq kg(-1), respectively. The Abu-Tartur phosphate deposit was found to have lower activity than many others exploited phosphate sedimentary deposits, with its average total annual dose being only 114.6 microSv y(-1). This value is about 11.46% 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.

  10. Analytical study of radionuclide concentration and radon exhalation rate in market available building materials of Ramsar

    NASA Astrophysics Data System (ADS)

    Bavarnegin, Elham; Vahabi-moghaddam, Masoud; Babakhani, Asad; Fathabadi, Nasrin

    2012-07-01

    Samples of structural and covering market available building materials from Ramsar, a northern city of Iran, were analyzed for their radon exhalation rate using an active radon gas analyzer with an emanation container. The radon exhalation rate varied from below the minimum detection limit of 0.01 to 0.31 Bq·m-2·h-1 with an average of 0.08 Bq·m-2·h-1. The 226Ra, 232Th, and 40K contents were also measured using a high resolution HPGe gamma-ray spectrometer system. The radionuclides contents varied from below the minimum detectable activity up to 73.5, 169, and 1,350 Bq.kg-1, with the average value of 16 ± 6, 25 ± 11, and 280 ± 101 Bq.kg-1, respectively. It was concluded from the results that some granite samples along with the block sample were the main source of radon exhalation rate, and the mean values of 226Ra, 232Th, and 40K in building material samples are below the world average values. Therefore, the use of these market available building materials in construction of Ramsar dwellings is considered to be safe for human habitation.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. Determination of the natural radioactivity levels in north west of Dukhan, Qatar using high-resolution gamma-ray spectrometry.

    PubMed

    Al-Sulaiti, Huda; Nasir, Tabassum; Al Mugren, K S; Alkhomashi, N; Al-Dahan, N; Al-Dosari, M; Bradley, D A; Bukhari, S; Matthews, M; Regan, P H; Santawamaitre, T; Malain, D; Habib, A

    2012-07-01

    This study is aimed at the determination of the activity concentrations of naturally occuring and technologically enhanced levels of radiation in 34 representative soil samples that have been collected from an inshore oil field area which was found to have, in a previous study, the highest observed value of 226Ra concentration among 129 soil samples. The activity concentrations of 238U and 226Ra have been inferred from gamma-ray transitions associated with their decay progenies and measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the values of the activity concentrations associated with the naturally occuring radionuclide chains for all the samples collected from NW Dukhan. Discrete-line, gamma-ray energy transitions from spectral lines ranging in energy from ∼100 keV up to 2.6 MeV have been associated with characteristic decays of the various decay products within the 235.8U and 232Th radioactive decay chains. These data have been analyzed, under the assumption of secular equilibrium for the U and Th decay chains. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented. The weighted mean value of the activity concentrations of 226Ra in one of the samples was found to be around a factor of 2 higher than the values obtained in the previous study and approximately a factor of 10 higher than the accepted worldwide average value of 35 Bq/kg. The weighted mean values of the activity concentrations of 232Th and 40K were also deduced and found to be within the worldwide average values of 30 and 400 Bq/kg, respectively. Our previous study reported a value of 201.9±1.5Stat.±13Syst.Bq/kg for 226Ra in one sample and further investigation in the current work determined a measured value for 226Ra of 342.00±1.9Stat.±25Syst.Bq/kg in a sample taken from the same locality. This is significantly higher than all the other

  17. Natural radioactivity in some major rivers of coastal Karnataka on the southwest coast of India.

    PubMed

    Narayana, Y; Rajashekara, K M; Siddappa, K

    2007-01-01

    Systematic studies on radiation level and distribution of radionuclides have been carried out in riverine environs of three major rivers of coastal Karnataka, viz. Kali, Sharavathi and Netravathi. The ambient gamma radiation levels along three rivers were measured using a portable plastic scintillometer. Activity concentrations of (226)Ra, (232)Th and (40)K in soil, sediment and rock were measured using a NaI(Tl) gamma-ray spectrometer. In the Kali, Sharavathi and Netravathi riverbanks, the median values of absorbed gamma dose rates in air were found to be 44 nGy h(-1), 35 nGy h(-1) and 57 nGy h(-1), respectively. The highest activity of (226)Ra was found in riverbank soil samples of Sharavathi River. The highest activities of (232)Th and (40)K were found in riverbank soil and sediment samples of Netravathi River. In Kali River, the highest (226)Ra activity was recorded for rock samples. To assess the radiological hazard of natural radioactivity in the samples, absorbed gamma dose rates in air, radium equivalent activity, representative level index, external hazard index and internal hazard index associated with the radionuclides were calculated and compared with internationally recommended values. The representative level index (I(gammar)) values are high in sediment samples of Netravathi River. The radium equivalent activity (Ra(eq)), external hazard index (H(ex)) and internal hazard index (H(in)) values are high in rock samples of Kali River. The results of these investigations are presented and discussed in this paper.

  18. Health assessment of natural radioactivity and radon exhalation rate in granites used as building materials in Lebanon.

    PubMed

    Kobeissi, M A; El-Samad, O; Rachidi, I

    2013-03-01

    Measurements of specific activities (Bq kg(-1)) of gamma-emissions from radioactive nuclides, (238)U, (226)Ra, (214)Bi, (232)Th, (212)Pb and (40)K, contained in 28 granite types, used as building materials in indoors in Lebanon, were performed on the powdered granites. The concentration of the nuclides, (226)Ra, (232)Th and (40)K, in the granites varied from below detection level (BDL) to 494 Bq kg(-1), BDL to 157.2 Bq kg(-1) and BDL to 1776 Bq kg(-1), respectively. (226)Ra concentration equivalents, C(Raeq), were obtained and ranged between 37 and 591 Bq kg(-1), with certain values above the allowed limit of 370 Bq kg(-1). Calculated annual gamma-absorbed dose in air, D(aR), varied from 17.7 to 274.5 (nGy h(-1)). Annual effective dose, E (mSv y(-1)), of gamma radiations related to the studied granites and absorbed by the inhabitants was evaluated. E (mSv y(-1)) ranged from 0.09 to 1.35 mSv y(-1). Some granite types produced E above the allowed limit of 1 mSv y(-1) set by ICRP. Values of (222)Rn mass exhalation rate, E(M) (mBq kg(-1)h(-1))(,) in granite powder were obtained using the CR-39 detector technique. Diffusion factors, f, in 23 granite types were calculated with f ranging between (0.1 ± 0.02)×10(-2) and (6.6 ± 1.01)×10(-2).

  19. 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

  20. 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.

  1. 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

  2. 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

  3. Intracellular potassium: 40K as a primordial gene irradiator.

    PubMed Central

    Moore, F D; Sastry, K S

    1982-01-01

    We have been interested in the possibility that the low energy electrons (Auger and Coster-Kronig) emitted after the electron capture decay of 40K may have highly localized radiochemical effects on the genetic material--effects dependent upon the intracellular locus of potassium. We report here that these effects are such that the likelihood of mutagenesis by their impact on DNA is substantial. This suggests that intracellular 40K has played a significant role as a mutagenic agent in evolution. PMID:6954503

  4. 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.

  5. Natural radionuclides and (137)Cs distributions and their relationship with sedimentological processes in Patras Harbour, Greece.

    PubMed

    Papaefthymiou, H; Papatheodorou, G; Moustakli, A; Christodoulou, D; Geraga, M

    2007-01-01

    Surficial and subsurficial sediment samples derived from gravity cores, selected from the harbour of Patras, Greece, were analyzed for grain size, water content, bulk density, specific gravity, organic carbon content and specific activities of natural radionuclides and (137)Cs. The specific activities of (232)Th, (226)Ra, (40)K and (137)Cs were measured radiometrically. The radionuclides (238)U and (232)Th were also analyzed using the INAA. The differences found between the specific activities of the natural radionuclides measured by the two methods are of no statistical significance. The sediment cores selection was based on a detailed bathymetric and marine seismic survey. Through the study of the detailed bathymetric map and the seismic profiles it was shown that ship traffic is highly influential to the harbour bathymetry. The granulometric and geotechnical properties of the sediments and therefore the specific activities of the natural radionuclides and (137)Cs seem to be controlled by the ship traffic. Relationship between radionuclide activity concentrations and granulometric/geotechnical parameters was defined after the treatment of all the analyses using R-mode factor analysis. The natural radionuclide activities are related to the fine fraction and bulk density of the sediments, while (137)Cs is mainly influenced by the organic carbon content. In addition, (238)U and (226)Ra seem to be in close relation with the heavy minerals fraction in coarse-grained sediments with high specific gravity.

  6. 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.

  7. The studies on radiological limits of color-glazed tiles used in home decoration.

    PubMed

    Yahong, Mao; Yigang, Liu; Guang, Zhang; Xiaolei, Hu

    2002-04-01

    This study was carried out to lay down the radiological limits of color-glazed tiles used in home decoration. The activity concentrations of various end products and raw materials as well as processed materials were measured using gamma spectroscopy. 222Rn exhalation rates from the surface of color-glazed tiles were measured using charcoal canister method. Levels of exposure to alpha ray and beta ray from the surface of glazed tiles were measured by surface alpha and beta contaminant instrument. The results show a great difference between the radioactive levels of the surface glaze and the matrix of color-glazed tiles. The 222Rn exhalation rates from the surface of color-glazed tiles are in the range of 10(-3) - 10(-4) Bq m(-2) s(-1). The concentrations of some natural radionuclides in glaze exceed the exempt limits of International Basic Safety Standards for Protection against Ionizing Radiation Sources (IAEA 1997). The limits for color-glazed tiles were deduced according to these data and the theory of UNSCEAR (1993). The activity concentration of 226Ra (Bq kg(-1)) in the glaze of color-glazed tiles should be in the range of A(226Ra) < or = 1,000 (Bq kg(-1)), and, at the same time, the specific activity of the natural radionuclides (Bq kg(-1)) should be in the range of A(232Th)/230 + A(226Ra)/310 + A(40K)/3,500 < or = 1. PMID:11906139

  8. Ground gamma-ray survey of the Solforata gas discharge area, Alban Hills-Italy: a comparison between field and laboratory measurements.

    PubMed

    Di Paolo, Federico; Plastino, Wolfango; Povinec, Pavel P; Bella, Francesco; Budano, Antonio; De Vincenzi, Mario; Laubenstein, Matthias; Ruggieri, Federico

    2013-01-01

    Measurements of environmental radioactivity by HPGe gamma-spectrometry were carried out with the aim of investigating the distribution of natural radionuclides in a volcanic area and to compare two different methodologies - an in situ gamma-survey of the area and high accuracy laboratory measurements of soil samples. Results demonstrate good performance of the in situ technique, also confirmed by a correlation analysis between the results obtained by the two methodologies. A volcanic gas discharge area was chosen as the test site for the presence of natural long-lived radionuclides such as (40)K and (238)U, (235)U and (232)Th, and their decay chain members. Clear evidence of (222)Rn degassing in the area was confirmed by (226)Ra values measured by the in situ technique. Higher (40)K values measured by the in situ technique may be attributed to the presence of vegetation in the study area. PMID:22982169

  9. 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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Measurement of the natural radioactivity in building materials used in Ankara and assessment of external doses.

    PubMed

    Turhan, S; Baykan, U N; Sen, K

    2008-03-01

    A total of 183 samples of 20 different commonly used structural and covering building materials were collected from housing and other building construction sites and from suppliers in Ankara to measure the natural radioactivity due to the presence of (226)Ra, (232)Th and (40)K. The measurements were carried out using gamma-ray spectrometry with two HPGe detectors. The specific activities of the different building materials studied varied from 0.5 +/- 0.1 to 144.9 +/- 4.9 Bq kg(-1), 0.6 +/- 0.2 to 169.9 +/- 6.6 Bq kg(-1) and 2.0 +/- 0.1 to 1792.3 +/- 60.8 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The results show that the lowest mean values of the specific activity of (226)Ra, (232)Th and (40)K are 0.8 +/- 0.5, 0.9 +/- 0.4 and 4.1 +/- 1.4 Bq kg(-1), respectively, measured in travertine tile while the highest mean values of the specific activity of the same radionuclides are 78.5 +/- 18.1 (ceramic wall tile), 77.4 +/- 53.0 (granite tile) and 923.4 +/- 161.0 (white brick), respectively. The radium equivalent activity (Ra(eq)), the gamma-index, the indoor absorbed dose rate and the corresponding annual effective dose were evaluated to assess the potential radiological hazard associated with these building materials. The mean values of the gamma-index and the estimated annual effective dose due to external gamma radiation inside the room for structural building materials ranged from 0.15 to 0.89 and 0.2 to 1.1 mSv, respectively. Applying criteria recently recommended for building materials in the literature, four materials meet the exemption annual dose criterion of 0.3 mSv, five materials meet the annual dose limit of 1 mSv and only one material slightly exceeds this limit. The mean values of the gamma-index for all building materials were lower than the upper limit of 1. PMID:18309197

  16. Measurement of the natural radioactivity in building materials used in Ankara and assessment of external doses.

    PubMed

    Turhan, S; Baykan, U N; Sen, K

    2008-03-01

    A total of 183 samples of 20 different commonly used structural and covering building materials were collected from housing and other building construction sites and from suppliers in Ankara to measure the natural radioactivity due to the presence of (226)Ra, (232)Th and (40)K. The measurements were carried out using gamma-ray spectrometry with two HPGe detectors. The specific activities of the different building materials studied varied from 0.5 +/- 0.1 to 144.9 +/- 4.9 Bq kg(-1), 0.6 +/- 0.2 to 169.9 +/- 6.6 Bq kg(-1) and 2.0 +/- 0.1 to 1792.3 +/- 60.8 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The results show that the lowest mean values of the specific activity of (226)Ra, (232)Th and (40)K are 0.8 +/- 0.5, 0.9 +/- 0.4 and 4.1 +/- 1.4 Bq kg(-1), respectively, measured in travertine tile while the highest mean values of the specific activity of the same radionuclides are 78.5 +/- 18.1 (ceramic wall tile), 77.4 +/- 53.0 (granite tile) and 923.4 +/- 161.0 (white brick), respectively. The radium equivalent activity (Ra(eq)), the gamma-index, the indoor absorbed dose rate and the corresponding annual effective dose were evaluated to assess the potential radiological hazard associated with these building materials. The mean values of the gamma-index and the estimated annual effective dose due to external gamma radiation inside the room for structural building materials ranged from 0.15 to 0.89 and 0.2 to 1.1 mSv, respectively. Applying criteria recently recommended for building materials in the literature, four materials meet the exemption annual dose criterion of 0.3 mSv, five materials meet the annual dose limit of 1 mSv and only one material slightly exceeds this limit. The mean values of the gamma-index for all building materials were lower than the upper limit of 1.

  17. Environmental gamma radiation measurement in district Swat, Pakistan.

    PubMed

    Jabbar, T; Khan, K; Subhani, M S; Akhter, P; Jabbar, A

    2008-01-01

    External exposure to environmental gamma ray sources is an important component of exposure to the public. A survey was carried out to determine activity concentration levels and associated doses from (226)Ra, (232)Th, (40)K and (137)Cs by means of high-resolution gamma ray spectrometry in the Swat district, famous for tourism. The mean concentrations for (226)Ra, (232)Th and (40)K were found to be 50.4 +/- 0.7, 34.8 +/- 0.7 and 434.5 +/- 7.4 Bq kg(-1), respectively, in soil samples, which are slightly more than the world average values. However, (137)Cs was only found in the soil sample of Barikot with an activity concentration of 34 +/- 1.2 Bq kg(-1). Only (40)K was determined in vegetation samples with an average activity of 172.2 +/- 1.7 Bq kg(-1), whereas in water samples, all radionuclides were found below lower limits of detection. The radium equivalent activity in all soil samples is lower than the limit set in the Organisation for Economic Cooperation and Development report (370 Bq kg(-1)). The value of the external exposure dose has been determined from the content of these radionuclides in soil. The average terrestrial gamma air absorbed dose rate was observed to be 62.4 nGy h(-1), which yields an annual effective dose of 0.08 mSv. The average value of the annual effective dose lies close to the global range of outdoor radiation exposure given in United Nations Scientific Committee on the Effects of Atomic Radiation. However, the main component of the radiation dose to the population residing in the study area arises from cosmic ray due to high altitude. PMID:18936087

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. Radium equivalent activity in the light of UNSCEAR report.

    PubMed

    Tufail, Muhammad

    2012-09-01

    Radium equivalent activity (Ra ( eq )) has been in practice for the last 40 years for the assessment of radiological hazard of radioactivity in environmental materials. The in-practice model for the calculation of the Ra ( eq ) has been critically reviewed in the light of the UNSCEAR 2000 report. Annual effective dose (E) values of (232)Th and (40)K were found to be not equal to that of (226)Ra derived from the activity concentrations of these radionuclides used in the expression for the Ra ( eq ). Therefore, a modified model has been proposed for the determination of the Ra ( eq ) for outdoor external exposure to gamma rays. The relation between the E and Ra ( eq ) has been explored. It is recommended that while describing the radiological hazard of the materials containing radioactivity, there should be no need to calculate the Ra ( eq ) if the E has already been determined or vice versa.

  15. 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.

  16. Natural radioactivity of granites used as building materials.

    PubMed

    Pavlidou, S; Koroneos, A; Papastefanou, C; Christofides, G; Stoulos, S; Vavelides, M

    2006-01-01

    Sixteen kinds of different granites, used as building materials, imported to Greece mainly from Spain and Brazil, were sampled and their natural radioactivity was measured by gamma-ray spectrometry. The activity concentrations of (238)U, (226)Ra, (232)Th and (40)K of granites are presented and compared to those of other building materials as well as other granite types used all over the world. In order to assess the radiological impact from the granites investigated, the absorbed and the effective doses were determined. Although the annual effective dose is higher than the limit of 1mSvy(-1) for some studied granites, they could be used safely as building materials, considering that their contribution in most of the house constructions is very low. An attempt to correlate the relatively high level of natural radioactivity, shown by some of the granites, with their constituent radioactive minerals and their chemical composition, was also made.

  17. Natural radioactivity levels of granites used in Turkey.

    PubMed

    Cetin, E; Altinsoy, N; Orgün, Y

    2012-08-01

    Thirty granite samples commonly used in Turkey were surveyed for natural radioactivity. Concentrations of natural radionuclides in all samples were determined by gamma-ray spectroscopy with hyper-pure germanium detector. The activity concentrations measured for (226)Ra and (232)Th ranged from 0.7±0.1 to 186±1 Bq kg(-1), and from 0.5±0.1 to 249±2 Bq kg(-1), respectively. The activity concentrations obtained for (40)K varied from minimum detectable activity (0.4 Bq kg(-1)) to 1935±11 Bq kg(-1). The radium equivalent activity (Ra(eq)), the absorbed dose rate (D), the external hazard index (H(ex)) and the annual effective dose equivalent were also calculated and compared with the international recommended values. Granite samples were also analysed mineralogically. It was observed that the presence of large amount orthoclase and radiogenic accessory minerals are the sources of high activity concentration levels.

  18. 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.

  19. Natural radioactivity and gamma dose from Sri Lankan clay bricks used in building construction.

    PubMed

    Hewamanna, R; Sumithrarachchi, C S; Mahawatte, P; Nanayakkara, H L; Ratnayake, H C

    2001-02-01

    The specific radioactivity concentrations of 226Ra, 232Th and 40K have been determined by gamma ray spectrometry with an HPGe detector in clay brick samples from kiln sites located in 17 towns. The average values of the measured activities are 35, 72, and 585 Bq kg(-1), respectively, for the above radionuclides. The average estimated radium equivalent concentration is 183 Bq kg(-1) and is comparable with reported values for many countries in the world. This value and the value obtained from the criteria formula suggest that the use of local clay bricks do not pose a radiological hazard. The calculated average absorbed dose rate in air within buildings was found to be 102 nGy h(-1) while the population weighted indoor annual effective dose was 0.20 mSv.

  20. 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

  1. 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.

  2. Natural radioactivity in soil in the Baluchistan province of Pakistan.

    PubMed

    Mujahid, S A; Hussain, S

    2010-08-01

    The measurements of natural radioactivity and the assessment of radiological hazards in the soil samples of Baluchistan province of Pakistan have been carried out using HPGe detector. The soil gas radon activities in these areas have also been measured using lucas cell technique. The measured activities of (226)Ra, (232)Th and (40)K were found in the range of 15-27, 20-37 and 328-648 Bq kg(-1), respectively. The calculated absorbed dose rate in air and the annual effective dose were in the range of 35-59 nGy h(-1) and 0.17-0.29 mSv, respectively. Radon activity in the soil gas was found in the range of 357-2476 Bq m(-3).

  3. Radioactivity in the indoor building environment in Serbia.

    PubMed

    Todorović, Natasa; Bikit, Istvan; Vesković, Miroslav; Krmar, Miodrag; Mrđa, Dusan; Forkapić, Sofija; Hansman, Jan; Nikolov, Jovana; Bikit, Kristina

    2014-01-01

    Measurement of activity concentrations of radionuclides in building materials and radon in indoor space is important in the assessment of population exposures, as most individuals spend 80 % of their time indoors. This paper presents the results of activity concentration measurements of: radon emanated from the soil, radionuclides (226)Ra, (232)Th and (40)K in the soil, indoor radon in the city of Novi Sad (the capital city of Vojvodina) using charcoal canisters and indoor radon in the Vojvodina region using alpha-track detectors and the radioactivity of some building materials. Influences of floor level, space under the rooms, boarding, and the heating system on indoor radon accumulation in the Vojvodina province, situated in the northern part of Serbia, are also presented in this paper. The total effective dose and the activity concentration index are calculated applying the dose criteria recommended by the European Union for building materials.

  4. Natural radioactivity in building materials used in Changzhi, China.

    PubMed

    Yang, Guang; Lu, Xinwei; Zhao, Caifeng; Li, Nan

    2013-08-01

    The natural radioactivity levels of the commonly used building materials collected from Changzhi, China was analysed using gamma-ray spectroscopy. The activity concentrations of (226)Ra, (232)Th and (40)K in the investigated building materials range from 14.6 to 131.2, from 9.9 to 138.8 and from 96.1 to 819.0 Bq kg(-1), respectively. The results were compared with the reported data of other countries and with the worldwide mean activity of soil. The external and internal hazard indices and gamma index were calculated to assess the radiation hazard to residents. The external hazard index of all building materials are less than unity, while the internal hazard and gamma indexes of hollow brick and gravel aggregate exceed unity. The study shows that the investigated hollow brick and gravel aggregate are not suitable for use as building materials in dwellings.

  5. 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.

  6. 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.

  7. Sedimentology models from activity concentration measurements: application to the "Bay of Cadiz" Natural Park (SW Spain).

    PubMed

    Ligero, R A; Vidal, J; Meléndez, M J; Hamani, M; Casas-Ruiz, M

    2009-03-01

    A previous study on seabed sediments of the Bay of Cadiz (SW of Spain) enabled us to identify several relations between sedimentological variables and activity concentrations of environmental radionuclides such as (137)Cs, (226)Ra, (232)Th and (40)K. In this paper the study has been extended to a large neighbouring inter-tidal area in order to establish if the above mentioned models can be generalized. As a result we have determined that the measured activity concentrations are closely to the values predicted by the theoretical models (correlation coefficient range=0.85-0.93). Furthermore, the proposal model for granulometric facies as a function of activity concentrations of the abovementioned radionuclides provides for the sediments distribution a representation which agrees with the values of the tidal energy distribution obtained using numeric models calibrated with experimental data from current meters and water level recorders. PMID:19136180

  8. 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

  9. A high natural radiation area in Khao-Than hot spring, Southern Thailand.

    PubMed

    Bhongsuwan, T; Auisui, S A

    2015-11-01

    Natural radioactivity in Khao-Than hot spring area, Surat Thani Province, Thailand was investigated. Gamma dose survey indicated a possible high radiation risk for this area. Rock, soil and hot spring mud samples were collected and analysed by a low background gamma spectrometer. The activity concentrations of (226)Ra, (232)Th and (40)K in samples were 151-139 092 (mean = 13 794), 12-596 (127), 24-616 (215) Bq kg(-1), respectively. X-ray diffraction and Fourier transform infrared spectroscopy indicated that quartz and calcite (CaCO3) are the main constituents in mud samples with varying contents. In conclusion, this study area was reasonably classified as a high natural background radiation area. The source of radium in this area is supposed to be related to the fault fluids enriched in radium that precipitated with calcium in the carbonate terrain and partly absorbed by high cation exchange capacity clays.

  10. Investigating the effect of using granite and marble as a building material on the radiation exposure of humans.

    PubMed

    Ebaid, Y Y; Bakr, W F

    2012-09-01

    The aim of this study was to comprehensively study the radiological hazards of granite and marble used as a building material in Egypt. The activity concentrations of (226)Ra, (232)Th and (40)K were determined using high-resolution hyper-pure germanium detectors in 25 samples of different types of commercially available granite and marble. The measured activity concentrations for these natural radionuclides were compared with the reported data for Egypt and other countries. In order to assess the radiological impact, the radiation hazard parameters such as radium equivalent activity (Ra(eq)) and hazard level index (I(γ)) were calculated. The internal and external dose rates due to natural radionuclides in granite and marble were also calculated. The data obtained were considered as helpful  in regulating the use of building materials in Egypt.

  11. Naturally occurring radioactive materials (NORM) in ashes from a fuel-oil power plant in Cienfuegos, Cuba, and the associated radiation hazards.

    PubMed

    Alonso-Hernández, C M; Bernal-Castillo, J; Morera-Gómez, Y; Guillen-Arruebarrena, A; Cartas-Aguila, H A; Acosta-Milián, R

    2014-03-01

    The radioactivity of NORM was measured in ashes collected from a fuel-oil power plant in Cienfuegos, Cuba, using an HPGe gamma-ray spectrometer. The (226)Ra, (210)Pb, (40)K, (232)Th and (238)U activity concentrations reached 240, 77, 59, 70 and 15 Bq kg(-1), respectively. The potential radiological hazard of these residuals was assessed. The radium equivalent activities of the samples varied from 54 to 345 Bq kg(-1). The gamma index was calculated to be lower than that of the reference values, and the gamma absorbed dose rate was higher than the average reported for the earth's crust; however, the assessed annual effective dose was slightly lower than the annual effective dose limit for public, i.e. 1 mSv. Therefore, these bottom ashes were not dramatically enriched with radionuclides and may be used as an additive for building materials without restrictions from a radiological protection point of view.

  12. 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.

  13. Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey

    NASA Astrophysics Data System (ADS)

    Akyuz, T.; Varinlioglu, A.; Kose, A.

    1999-01-01

    Gamma-isotopic analysis of the ashes produced by the combustion of lignite in power stations of Turkey together with the parent coal samples was performed with the aim to estimate its potential adverse impacts on human health. Gamma-isotopic analysis indicated that all samples contained226Ra (coal samples: 89 148 Bq kg-1; ash samples: 15 26 Bq kg-1),238U (coal samples: 2 4 μg g-1; ash samples: 9 33 μg g-1),232Th (coal samples: 1 9 μg g-1; ash samples: 8 12μg g-1), and40K (coal samples: 26 67 Bq kg-1; ash samples: not detected).134Cs and137Cs have not been found in the samples.

  14. Gamma isotopic analysis of the coals and ashes from coal fired power plants of Turkey

    NASA Astrophysics Data System (ADS)

    Akyuz, T.; Varinlioglu, A.; Kose, A.

    1999-01-01

    Gamma-isotopic analysis of the ashes produced by the combustion of lignite in power stations of Turkey together with the parent coal samples was performed with the aim to estimate its potential adverse impacts on human health. Gamma-isotopic analysis indicated that all samples contained226Ra (coal samples: 89-148 Bq kg-1; ash samples: 15-26 Bq kg-1),238U (coal samples: 2-4 μg g-1; ash samples: 9-33 μg g-1),232Th (coal samples: 1-9 μg g-1; ash samples: 8-12μg g-1), and40K (coal samples: 26-67 Bq kg-1; ash samples: not detected).134Cs and137Cs have not been found in the samples.

  15. Investigation of the radiological impact on the coastal environment surrounding a fertilizer plant.

    PubMed

    El Samad, O; Aoun, M; Nsouli, B; Khalaf, G; Hamze, M

    2014-07-01

    This investigation was carried out in order to assess the marine environmental radioactive pollution and the radiological impact caused by a large production plant of phosphate fertilizer, located in the Lebanese coastal zone. Natural radionuclides ((238)U, (235)U, (232)Th, (226)Ra, (210)Po, (210)Pb, (40)K) and anthropogenic (137)Cs were measured by alpha and gamma spectrometry in seawater, sediment, biota and coastal soil samples collected from the area impacted by this industry. The limited environmental monitoring program within 2 km of the plant indicates localized contamination with radionuclides of the uranium decay chain mainly due to the transport, the storage of raw materials and the free release of phosphogypsum waste.

  16. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca.

    PubMed

    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 surrounding 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.

  17. Assessment of Radiation and Heavy Metals Risk due to the Dietary Intake of Marine Fishes (Rastrelliger kanagurta) from the Straits of Malacca.

    PubMed

    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 surrounding 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

  18. A high natural radiation area in Khao-Than hot spring, Southern Thailand.

    PubMed

    Bhongsuwan, T; Auisui, S A

    2015-11-01

    Natural radioactivity in Khao-Than hot spring area, Surat Thani Province, Thailand was investigated. Gamma dose survey indicated a possible high radiation risk for this area. Rock, soil and hot spring mud samples were collected and analysed by a low background gamma spectrometer. The activity concentrations of (226)Ra, (232)Th and (40)K in samples were 151-139 092 (mean = 13 794), 12-596 (127), 24-616 (215) Bq kg(-1), respectively. X-ray diffraction and Fourier transform infrared spectroscopy indicated that quartz and calcite (CaCO3) are the main constituents in mud samples with varying contents. In conclusion, this study area was reasonably classified as a high natural background radiation area. The source of radium in this area is supposed to be related to the fault fluids enriched in radium that precipitated with calcium in the carbonate terrain and partly absorbed by high cation exchange capacity clays. PMID:25956781

  19. A methodology for assessing the maximum expected radon flux from soils in northern Latium (central Italy).

    PubMed

    Voltaggio, Mario; Masi, Umberto; Spadoni, Massimo; Zampetti, Giorgio

    2006-12-01

    Northern Latium (Italy) is an area where the Rn risk rate is potentially high because of the extensive outcropping of Neogene U-rich volcanics and the presence of major active tectonic lineaments. The lack of data on Rn risk rates in that area, which is undergoing major urban and industrial development, has prompted this study. It proposes a methodology to evaluate the maximum potential diffusive Rn flux from soils based on the measurement of (226)Ra, (232)Th and (40)K activities by gamma-ray spectrometry, and the measurement of main soil parameters influencing the Rn emanation. This methodology provides a simple, reliable and low-cost tool for drawing up radon flux maps useful to both public planners and private individuals, who want to operate safely in the study area. The proposed methodology may also be applied to other geographic areas outside the prescribed study area.

  20. Investigation of the radiological impact on the coastal environment surrounding a fertilizer plant.

    PubMed

    El Samad, O; Aoun, M; Nsouli, B; Khalaf, G; Hamze, M

    2014-07-01

    This investigation was carried out in order to assess the marine environmental radioactive pollution and the radiological impact caused by a large production plant of phosphate fertilizer, located in the Lebanese coastal zone. Natural radionuclides ((238)U, (235)U, (232)Th, (226)Ra, (210)Po, (210)Pb, (40)K) and anthropogenic (137)Cs were measured by alpha and gamma spectrometry in seawater, sediment, biota and coastal soil samples collected from the area impacted by this industry. The limited environmental monitoring program within 2 km of the plant indicates localized contamination with radionuclides of the uranium decay chain mainly due to the transport, the storage of raw materials and the free release of phosphogypsum waste. PMID:23768871

  1. 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.

  2. 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.

  3. Assessment of radiological hazards of clay bricks fabricated in the Punjab province of Pakistan.

    PubMed

    Asghar, M; Tufail, M; Khan, K; Mahmood, A

    2010-12-01

    The Punjab is the most populous among the four provinces of Pakistan, which has around 72 million of people and 205 344 km(2) of land. The majority of the population of this province lives in houses made of clay bricks that contain variable amounts of naturally occurring radioactive material (NORM). The concentration level of NORM in clay bricks used to construct dwellings may pose health hazards to inhabitants if it exceeds the permissible limits. For radiological surveillance, activity concentrations of the primordial radionuclides (40)K, (226)Ra and (232)Th were measured in 140 brick samples collected from 35 districts of the Punjab province. A high-purity germanium gamma-ray detector coupled with a personal computer-based multichannel analyzer was employed for the measurement of activity concentrations of primordial radionuclides in the brick samples. The province-wide average activity concentrations and the range (given in parenthesis) of (40)K, (226)Ra and (232)Th were found to be 624 ± 133 (299-918), 35 ± 7 (21-47) and 42 ± 8 (22-58) Bq kg(-1), respectively. The values lie within the range of activity concentration values for clay bricks of some countries of Asia. Potential radiological constraint was checked in the form of hazard indices calculated from the measured activity concentrations; the indices were found to be less than their limiting values. Indoor external dose was calculated for a standard size room made of clay bricks, and the dose rate was 159 ± 30 (83-219) nGy h(-1). The average value of the dose rate is comparable to that of Asian countries and is about twice the worldwide average value. Annual effective dose E(ff) in the bricks-made room was calculated and the average value of the dose was 0.80 mSv y(-1), which is about twice the worldwide background value of 0.41 mSv y(-1).

  4. Radiological impacts of the usability of clay and kaolin as raw material in manufacturing of structural building materials in Turkey.

    PubMed

    Turhan, Seref

    2009-03-01

    The aim of the present study is to measure the natural radioactivity due to the presence of radionuclides in clay and kaolin, used widely as raw materials in ceramics, bricks and cement industries, and to assess the possible radiological hazards associated with these raw materials. The activity concentrations of natural radionuclides (226)Ra, (232)Th and (40)K in 50 samples collected from different quarries were measured by means of gamma-ray spectrometry with an HPGe detector. The mean values of the measured activity concentrations of (226)Ra, (232)Th and (40)K for clay samples were found to be 39.3 +/- 22.7 Bq kg(-1), 49.6 +/- 27.9 Bq kg(-1) and 569.5 +/- 181.0 Bq kg(-1), and for kaolin samples 82.0 +/- 37.3 Bq kg(-1), 94.8 +/- 49.2 Bq kg(-1) and 463.6 +/- 544.9 Bq kg(-1), respectively. These levels are comparable to those appearing in clays of European countries. The radium equivalent activity and the external (gamma) and internal (alpha) hazard indices were calculated to assess the potential radiological hazard. The calculated gamma and alpha indices varied from 0.19 to 1.17 and from 0.04 to 0.47 for clay samples and from 0.36 to 1.75 and from 0.08 to 0.63, respectively. The mean value of the gamma index for the clay samples (0.57 +/- 0.24) is slightly above the criterion of 0.5 corresponding to an annual effective dose of 0.3 mSv, while the mean value of the gamma index for the kaolin samples (0.90 +/- 0.49) is below the criterion of unity corresponding to an annual effective dose of 1 mSv. The calculated alpha index values for all samples are below the recommended upper level.

  5. 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.

  6. 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.

  7. Natural radioactivity measurement in pumice samples used raw materials in Turkey.

    PubMed

    Turhan, S; Yücel, H; Gündüz, L; Sahin, S; Vural, M; Parmaksiz, A; Demircioglu, B

    2007-03-01

    The activity concentrations of 232Th, 226Ra, and 40K in different pumice samples have been determined by high-resolution gamma-ray spectrometry using a 110% HpGe detector. The radium equivalent activities (Raeq), external hazard index (Hex), and internal hazard index (Hin) associated with the natural radionuclides and representative level index (Igamma r) are calculated to assess the radiation hazard of the natural radioactivity in the pumice samples. The mean values of the measured radioactivity concentrations of 232Th, 226Ra, and 40K for pumice samples from the region of lakes (ROL) are 232.4+/-8.0, 196.9+/-7.8, and 1325.8+/-20.4 Bqkg(-1) and for pumice samples from Cukurova region (CR) 16.3+/-4.0, 16.1+/-4.9, and 479.7+/-170.4 Bqkg(-1), respectively. The calculated Raeq values vary from 435.9+/-12.5 to 883.6+/-41.5 Bqkg(-1) with a mean of 630.9+/-20.2 Bqkg(-1) for the ROL samples and from 49.7+/-3.3 to 101.9+/-7.2 Bqkg(-1) with a mean of 76.3+/-23.7 Bqkg(-1) for the CR samples. For the ROL samples, Raeq are above the limit of 370 Bqkg(-1), equivalent to external gamma dose of 1.5 mSv yr(-1), recommended for the safe use of construction materials by NEA-OECD, while for the CR samples, Raeq values are lower than the limit.

  8. Study on radionuclides in granite quarries of Bangalore rural district, Karnataka, India.

    PubMed

    Ningappa, C; Sannappa, J; Karunakara, N

    2008-01-01

    Studies on natural radiation levels and radionuclides were carried out extensively in the environment of granite quarries of Kanakapura, Ramanagara Taluks and Bidadi Hobli in Bangalore rural District and Bangalore city. The indoor and outdoor gamma exposure rate in air was measured using an environmental dosemeter, and it is converted into absorbed dose using suitable conversion factor. The activity concentrations of natural radionuclides in rock samples and also in soil samples were measured using an HPGe gamma-ray spectrometer. The results reveal that the activity concentrations of (226)Ra, (232)Th and (40)K in rocks are found to be vary from 32.2 to 163.6, 128.3 to 548.6 and 757.4 to 1418.4 Bq kg(-1), respectively, with corresponding arithmetic mean values of 93.2, 306.2 and 1074.4 Bq kg(-1). Activity concentrations of (226)Ra, (232)Th and (40)K in soil samples were found to vary from 32.4 to 55.2, 39.9 to 214.3 and 485.4 to 1150.2 Bq kg(-1), respectively, with corresponding arithmetic mean values of 40.7, 93.1 and 750.4 Bq kg(-1). The average activity levels of all these radionuclides are above the global average. This is consistent with the geological and geo-chemical significance of the rocks of the area under investigation. The results of these systematic investigations are discussed in detail and compared with the literature values represented for other environments.

  9. 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).

  10. Radiological hazards due to naturally occurring radionuclides in the selected building materials used for the construction of dwellings in four districts of the Punjab Province, Pakistan.

    PubMed

    Rahman, S U; Rafique, M; Jabbar, A; Matiullah

    2013-03-01

    This paper presents the finding of a study undertaken to determine the naturally occurring radionuclides present in commonly used building materials for dwellings and workplaces in four districts of the Punjab Province, Pakistan. The concentrations of (226)Ra, (232)Th and (40)K were measured by using gamma-ray spectroscopy. A total of 80 samples of building materials were collected from various manufacturers and suppliers of the studied area. The specific activities of (226)Ra, (232)Th and (40)K were measured in building samples, and results ranged from minimum values of 9 ± 1, 9 ± 2 and 27 ± 8 Bq kg(-1) to maximum values of 106 ± 5, 133 ± 5 and 914 ± 21 Bq kg(-1) with mean values of 42 ± 3, 48 ± 3 and 376 ± 16 Bq kg(-1), respectively. From the measured activity concentrations, equivalent radium (Ra(eq)), terrestrial absorbed dose rate, annual effective dose as well as external and internal hazard indices were calculated and found to range from 52 ± 7 to 274 ± 15 Bq kg(-1), 23 ± 3 to 130 6 nGy h(-1), 0.15 ± 0.02 to 0.80 ± 0.03 mSv, 0.14 ± 0.02 to 0.75 ± 0.04 and 0.2 ± 0.02 to 0.98 ± 0.05, respectively. These results were comparable to the results of similar studies undertaken locally and in other countries. The samples considered were safe for use in construction of dwellings in the study area and do not pose any significant source of radiation hazard.

  11. Assessment of natural radioactivity in phosphate ore, phosphogypsum and soil samples around a phosphate fertilizer plant in Nigeria.

    PubMed

    Okeji, Mark C; Agwu, Kenneth K; Idigo, Felicitas U

    2012-11-01

    The radionuclides present in phosphate ore, phosphogypsum and soil samples in the vicinity of a phosphate fertilizer plants in Nigeria were identified and their activity concentration determined to assess the potential radiation impact on the environment due to fertilizer production. The mean activity concentration of (238)U, (232)Th, and (40)K radionuclides in phosphate ore samples were 616 ± 38.6, BDL (Below Detection Level) and 323.7 ± 57.5 Bq kg(-1) respectively. For the phosphogypsum, 334.8 ± 8.8, 4.0 ± 1.4, and 199.9 ± 9.3 Bq kg(-1) respectively and for soil samples range from 20.5 ± 7.3 to 175.7 ± 10.5 Bq kg(-1) for (226)Ra, 15.5 ± 1.5 to 50.4 ± 0.6 Bq kg(-1) for (232)Th and 89.5 ± 8.1 to 316.1 ± 41.3 Bq kg(-1) for (40)K respectively. The mean absorbed dose rate was 71.4 nGy h(-1). The mean annual effective dose was 86 μSv.

  12. 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.

  13. 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.

  14. Indoor radon in a Spanish region with different gamma exposure levels.

    PubMed

    Quindós, L S; Fernández, P L; Sainz, C; Fuente, I; Nicolás, J; Quindós, L; Arteche, J

    2008-10-01

    In the beginning of 1990s within the framework of a national radon survey of more than 1500 points, radon measurements were performed in more than 100 houses located in Galicia region, in the Northwest area of Spain. The houses were randomly selected only bearing in mind general geological aspects of the region. Subsequently, a nationwide project called MARNA dealt with external gamma radiation measurements in order to draw a Spanish natural radiation map. The comparison in Galicia between these estimations and the indoor radon levels previously obtained showed good agreement. With the purpose of getting a confirmation of this relationship and also of creating a radon map of the zone, a new set of measurements were carried out in 2005. A total of 300 external gamma radiation measurements were carried out as well as 300 measurements of 226Ra, 232Th and 40K content in soil. Concerning radon, 300 1-m-depth radon measurements in soil were performed, and indoor radon concentration was determined in a total of 600 dwellings. Radon content in soil gave more accurate indoor radon predictions than external gamma radiation or 226Ra concentration in soil.

  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. 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.

  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. 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

  19. 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

  20. 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

  1. Radiological exposure assessment from soil, underground and surface water in communities along the coast of a shallow water offshore oilfield in Ghana.

    PubMed

    Kpeglo, D O; Mantero, J; Darko, E O; Emi-Reynolds, G; Akaho, E H K; Faanu, A; Garcia-Tenorio, R

    2015-02-01

    Radiometric determinations have been carried out to assess public exposure to radioactivity for communities along the coast of a shallow water offshore oilfield in Ghana (which started their operations recently) in order to establish baseline data using alpha spectrometry after radiochemical separation and non-destructive gamma spectrometry. The average activity concentrations of (234)U, (238)U, (230)Th and (232)Th by alpha-particle spectrometry and of (226)Ra, (228)Ra, (228)Th, (40)K, (210)Pb, (234)Th and (137)Cs by gamma-ray spectrometry were determined in the soil samples. The activity concentrations of (234)U, (238)U, (230)Th and (232)Th were determined in the water samples by alpha-particle spectrometry and of (226)Ra by liquid scintillation counting. The total annual effective dose to the public was estimated from the measured activity concentrations and this was clearly below the International Commission on Radiological Protection (ICRP) reference level of 1 mSv y(-1) for public exposure control. In addition, the estimated values of Raeq, Hex and Hin were all lower than the recommended acceptable values and the mean values of gross alpha and gross beta determinations performed for all the water samples give values that were all below the Ghana Standards Authority and World Health Organization recommended guideline values for drinking water quality. The results obtained show insignificant public exposure to radioactivity. However, this study provides important information for future studies on subsequent evaluations of the possible future environmental contamination due to activities of the oil industry in Ghana.

  2. 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)).

  3. 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)

  4. 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.

  5. 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.

  6. 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

  7. 76 FR 31379 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ...-232 (Th-232) and radium-226 (Ra-226) are provided in the revised DP. Small quantities of Th-232 and Ra... Soil DCGLs Addendum Soil DCGLs for Thorium and Radium). The revised DP does not change any previously... Radium. August 2010. ABB, Inc. Decommissioning Plan, Revision 2, CE X X ML102310553 X Windsor...

  8. 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.

  9. 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

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. Measurements of natural radioactivity and radon exhalation rates from different brands of cement used in Pakistan.

    PubMed

    Mujahid, S A; Rahim, A; Hussain, S; Farooq, M

    2008-01-01

    The measurement of activity due to the naturally occurring radionuclide has been carried out in different brands of cement available in Pakistan. The gamma spectra of the collected samples were obtained using high-purity germanium detector and analysed for the presence of 232Th, 238U and 40K. The assessment of radiological hazards due to these radionuclides has also been made. The studies concerning the determination of radon-exhalation rates from these samples of cement were also carried out using CR-39 based NRPB radon dosimeters. The range of activity concentrations were found for 226Ra (from 25.10 +/- 1.55 to 52.60 +/- 3.20 Bq kg(-1)), 232Th (from 10.30 +/- 0.65 to 30.40 +/- 1.70 Bq kg(-1)) and 40K (from 17.25 +/- 1.55 to 292.95 +/- 23.05 Bq kg(-1)). The estimated value of radium equivalent concentration was from 11.16 +/- 2.60 to 114.98 +/- 7.11 Bq kg(-1). The calculated absorbed dose rate in air and the annual effective dose were in the range from 18.54 +/- 1.17 to 52.90 +/- 3.31 nGy h(-1) and 0.09 +/- 0.01 to 0.26 +/- 0.02 mSv, respectively. The external and internal hazard indices were in the range from 0.11 +/- 0.01 to 0.31 +/- 0.02 and 0.18 +/- 0.01 to 0.45 +/- 0.03, respectively. The radon exhalation rates from different brands of cement were found in the range from 3.3 +/- 0.7 to 8.1 +/- 1.7 mBq kg(-1) h(-1).

  15. 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.

  16. Distribution of natural and artificial radionuclides in chernozem soil/crop system from stationary experiments.

    PubMed

    Sarap, Nataša B; Rajačić, Milica M; Đalović, Ivica G; Šeremešić, Srđan I; Đorđević, Aleksandar R; Janković, Marija M; Daković, Marko Z

    2016-09-01

    The present paper focuses on the determination of radiological characteristics of cultivated chernozem soil and crops from long-term field experiments, taking into account the importance of distribution and transfer of radionuclides in the soil-plant system, especially in agricultural cropland. The investigation was performed on the experimental fields where maize, winter wheat, and rapeseed were cultivated. Analysis of radioactivity included determination of the gross alpha and beta activity as a screening method, as well as the activities of the following radionuclides: natural ((210)Pb, (235)U, (238)U, (226)Ra, (232)Th, (40)K, (7)Be) and artificial ((90)Sr and (137)Cs). The activities of natural and artificial ((137)Cs) radionuclides were determined by gamma spectrometry, while the artificial radionuclide (90)Sr was determined by a radiochemical analytical method. Based on the obtained results for the specific activity of (40)K, (137)Cs, and (90)Sr, accumulation factors for these radionuclides were calculated in order to estimate transfer of radionuclides from soil to crops. The results of performed analyses showed that there is no increase of radioactivity that could endanger the food production through the grown crops. PMID:27250084

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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

  6. Exploring an ultracold Fermi-Fermi mixture: interspecies Feshbach resonances of ^6Li-^40K

    NASA Astrophysics Data System (ADS)

    Schreck, Florian

    2008-03-01

    We report on the observation of interspecies Feshbach resonances in an ultracold mixture of two fermionic species, ^6Li and ^40K. Interpretation of the data unambiguously assigns molecular bound states to the various resonances and fully characterizes the ground-state scattering properties in any combination of spin states. Using this knowledge we hope to be able to produce ^6Li-^40K molecules, cool them to quantum degeneracy, and study their BEC-BCS crossover. In collaboration with: F. Schreck, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; E. Wille, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; F.M. Spiegelhalder, G. Kerner, D. Naik, A. Trenkwalder, G. Hendl, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; R. Grimm, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; T.G. Tiecke, J.T.M. Walraven,Van der Waals-Zeeman Institute of the University of Amsterdam, 1018 XE, The Netherlands; S.J.J.M.F. Kokkelmans, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; E. Tiesinga, P.S. Julienne, Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899-8423, USA

  7. 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.

  8. (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

  9. 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.

  10. Body K and 40K in Chinese subjects measured with a whole-body counter

    SciTech Connect

    Lan, C.Y.; Weng, P.S. )

    1989-11-01

    More than 380 Chinese adults of both sexes were studied for their total body K and 40K using the National Tsing Hua University whole-body counter. The K values were found to have an average of 1.75 {plus minus} 0.4 g K kg-1 body weight for males and 1.41 {plus minus} 0.1 g K kg-1 body weight for females. The average K value for both sexes was 1.69 {plus minus} 0.4 g K kg-1 body weight. The annual absorbed dose for the average male was calculated to be 0.21 {plus minus} 0.04 mGy and for the average female was 0.17 {plus minus} 0.01 mGy. The average for both sexes was 0.20 {plus minus} 0.04 mGy. The 40K activity per unit body weight varied inversely with slenderness, and total body K varied directly with body-build index.

  11. (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.

  12. 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

  13. 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

  14. Natural radioactivity, radon exhalation rates and indoor radon concentration of some granite samples used as construction material in Turkey.

    PubMed

    Aykamis, Ahmet S; Turhan, Seref; Aysun Ugur, F; Baykan, Umut N; Kiliç, Ahmet M

    2013-11-01

    It is very important to determine the levels of the natural radioactivity in construction materials and radon exhalation rate from these materials for assessing potential exposure risks for the residents. The present study deals with 22 different granite samples employed as decoration stones in constructions in Turkey. The natural radioactivity in granite samples was measured by gamma-ray spectrometry with an HPGe detector. The activity concentrations of (226)Ra, (232)Th and (40)K were found to be in the range of 10-187, 16-354 and 104-1630 Bq kg(-1), respectively. The radon surface exhalation rate and the radon mass exhalation rate estimated from the measured values of (226)Ra content and material properties varied from 1.3 to 24.8 Bq m(-2) h(-1) with a mean of 10.5±1.5 Bq m(-2) h(-1) and 0.03-0.64 Bq kg(-1) h(-1) with a mean of 0.27±0.04 Bq kg(-1) h(-1), respectively. Radon concentrations in the room caused from granite samples estimated using a mass balance equation varied from 23 to 461 Bq m(-3) with a mean of 196±27 Bq m(-3). Also the gamma index (Iγ), external indoor annual effective dose (Eγ) and annual effective dose due to the indoor radon exposure (ERn) were estimated as the average value of 1.1±0.1, 0.16±0.02 mSv and 5.0±0.7 mSv, respectively, for the granite samples. PMID:23633647

  15. External gamma-ray dose rate and radon concentration in indoor environments covered with Brazilian granites.

    PubMed

    Anjos, R M; Juri Ayub, J; Cid, A S; Cardoso, R; Lacerda, T

    2011-11-01

    Health hazard from natural radioactivity in Brazilian granites, covering the walls and floor in a typical dwelling room, was assessed by indirect methods to predict external gamma-ray dose rates and radon concentrations. The gamma-ray dose rate was estimated by a Monte Carlo simulation method and validated by in-situ measurements with a NaI spectrometer. Activity concentrations of (232)Th, (226)Ra, and (40)K in an extensive selection of Brazilian commercial granite samples measured by using gamma-ray spectrometry were found to be 4.5-450 Bq kg(-1), 4.9-160 Bq kg(-1) and 190-2029 Bq kg(-1), respectively. The maximum external gamma-ray dose rate from floor and walls covered with the Brazilian granites in the typical dwelling room (5.0 m × 4.0 m area, 2.8 m height) was found to be 120 nGy h(-1), which is comparable with the average worldwide exposure to external terrestrial radiation of 80 nGy h(-1) due to natural sources, proposed by United Nations Scientific Committee on the Effects of Atomic Radiation. Radon concentrations in the room were also estimated by a simple mass balance equation and exhalation rates calculated from the measured values of (226)Ra concentrations and the material properties. The results showed that the radon concentration in the room ventilated adequately (0.5 h(-1)) will be lower than 100 Bq m(-3), value recommended as a reference level by the World Health Organization.

  16. Enhancement of natural radionuclides in the surroundings of the four largest coal-fired power plants in Spain.

    PubMed

    Baeza, A; Corbacho, J A; Guillén, J; Salas, A; Mora, J C; Robles, B; Cancio, D

    2012-03-01

    The production of electricity in coal-fired power plants (CFPP) is considered a NORM (Naturally Occurring Radioactive Materials) activity because the coals they burn can present relatively high contents of the naturally occurring radionuclides. In this study, the main radiological impact pathways into the surrounding environments of the four largest coal-fired power plants in Spain were analyzed. These pathways are, first, atmospheric evacuations and wind resuspension and, second, effluent evacuations to nearby rivers or directly to the sea. The atmospheric releases of radionuclides were evaluated by the analyses of soil profiles in the vicinities of the CFPPs. No significant enhancement of radionuclides in the surface soil was observed at the points of maximum deposition of combustion gases, located from 4.3 to 13 km away depending on the considered CFPP. However, an increase of (40)K, (226)Ra, and (232)Th in the surface soils was observed in the first kilometre from the chimney for two CFPPs. This suggested that these radionuclides were released in particulate form. There was also a net influence of the climate in which the CFPPs were located. This was observed in the two CFPPs that were in dry environments, while no increase was observed in the other two, located in more humid environments. The liquid effluents released usually presented an enhancement of dissolved chemical species regarding the initial intake water. Enrichments of the (234,238)U and (226)Ra contents in the water used in the plants' routine procedures were observed, and of (210)Po in the wastewater of just one of the plants. In any case, this enhancement was below the parametric value for the Total Indicative Dose for the hypothetical human consumption of the released waters. As a consequence of these releases of radionuclides, local products destined for human consumption produced in the vicinity of the facilities might incorporate natural radionuclides by these pathways, finding no significant

  17. Enhancement of natural radionuclides in the surroundings of the four largest coal-fired power plants in Spain.

    PubMed

    Baeza, A; Corbacho, J A; Guillén, J; Salas, A; Mora, J C; Robles, B; Cancio, D

    2012-03-01

    The production of electricity in coal-fired power plants (CFPP) is considered a NORM (Naturally Occurring Radioactive Materials) activity because the coals they burn can present relatively high contents of the naturally occurring radionuclides. In this study, the main radiological impact pathways into the surrounding environments of the four largest coal-fired power plants in Spain were analyzed. These pathways are, first, atmospheric evacuations and wind resuspension and, second, effluent evacuations to nearby rivers or directly to the sea. The atmospheric releases of radionuclides were evaluated by the analyses of soil profiles in the vicinities of the CFPPs. No significant enhancement of radionuclides in the surface soil was observed at the points of maximum deposition of combustion gases, located from 4.3 to 13 km away depending on the considered CFPP. However, an increase of (40)K, (226)Ra, and (232)Th in the surface soils was observed in the first kilometre from the chimney for two CFPPs. This suggested that these radionuclides were released in particulate form. There was also a net influence of the climate in which the CFPPs were located. This was observed in the two CFPPs that were in dry environments, while no increase was observed in the other two, located in more humid environments. The liquid effluents released usually presented an enhancement of dissolved chemical species regarding the initial intake water. Enrichments of the (234,238)U and (226)Ra contents in the water used in the plants' routine procedures were observed, and of (210)Po in the wastewater of just one of the plants. In any case, this enhancement was below the parametric value for the Total Indicative Dose for the hypothetical human consumption of the released waters. As a consequence of these releases of radionuclides, local products destined for human consumption produced in the vicinity of the facilities might incorporate natural radionuclides by these pathways, finding no significant

  18. Natural radioactivity, radon exhalation rates and indoor radon concentration of some granite samples used as construction material in Turkey.

    PubMed

    Aykamis, Ahmet S; Turhan, Seref; Aysun Ugur, F; Baykan, Umut N; Kiliç, Ahmet M

    2013-11-01

    It is very important to determine the levels of the natural radioactivity in construction materials and radon exhalation rate from these materials for assessing potential exposure risks for the residents. The present study deals with 22 different granite samples employed as decoration stones in constructions in Turkey. The natural radioactivity in granite samples was measured by gamma-ray spectrometry with an HPGe detector. The activity concentrations of (226)Ra, (232)Th and (40)K were found to be in the range of 10-187, 16-354 and 104-1630 Bq kg(-1), respectively. The radon surface exhalation rate and the radon mass exhalation rate estimated from the measured values of (226)Ra content and material properties varied from 1.3 to 24.8 Bq m(-2) h(-1) with a mean of 10.5±1.5 Bq m(-2) h(-1) and 0.03-0.64 Bq kg(-1) h(-1) with a mean of 0.27±0.04 Bq kg(-1) h(-1), respectively. Radon concentrations in the room caused from granite samples estimated using a mass balance equation varied from 23 to 461 Bq m(-3) with a mean of 196±27 Bq m(-3). Also the gamma index (Iγ), external indoor annual effective dose (Eγ) and annual effective dose due to the indoor radon exposure (ERn) were estimated as the average value of 1.1±0.1, 0.16±0.02 mSv and 5.0±0.7 mSv, respectively, for the granite samples.

  19. External gamma-ray dose rate and radon concentration in indoor environments covered with Brazilian granites.

    PubMed

    Anjos, R M; Juri Ayub, J; Cid, A S; Cardoso, R; Lacerda, T

    2011-11-01

    Health hazard from natural radioactivity in Brazilian granites, covering the walls and floor in a typical dwelling room, was assessed by indirect methods to predict external gamma-ray dose rates and radon concentrations. The gamma-ray dose rate was estimated by a Monte Carlo simulation method and validated by in-situ measurements with a NaI spectrometer. Activity concentrations of (232)Th, (226)Ra, and (40)K in an extensive selection of Brazilian commercial granite samples measured by using gamma-ray spectrometry were found to be 4.5-450 Bq kg(-1), 4.9-160 Bq kg(-1) and 190-2029 Bq kg(-1), respectively. The maximum external gamma-ray dose rate from floor and walls covered with the Brazilian granites in the typical dwelling room (5.0 m × 4.0 m area, 2.8 m height) was found to be 120 nGy h(-1), which is comparable with the average worldwide exposure to external terrestrial radiation of 80 nGy h(-1) due to natural sources, proposed by United Nations Scientific Committee on the Effects of Atomic Radiation. Radon concentrations in the room were also estimated by a simple mass balance equation and exhalation rates calculated from the measured values of (226)Ra concentrations and the material properties. The results showed that the radon concentration in the room ventilated adequately (0.5 h(-1)) will be lower than 100 Bq m(-3), value recommended as a reference level by the World Health Organization. PMID:21729819

  20. Assessment of radionuclide contents in food in Hong Kong

    SciTech Connect

    Yu, K.N.; Mao, S.Y.

    1999-12-01

    Baseline values of concentrations of the natural radionuclides ({sup 238}U, {sup 226}Ra, {sup 228}Ra/{sup 232}Th, {sup 210}Pb) and artificial radionuclides ({sup 137}Cs, {sup 60}Co) in food and drinks (tap water, milk, and water-based drinks) were determined by gamma spectroscopy. All food and drinks were found to contain detectable {sup 40}K contents: 0.1 to 160 Bq Kg{sup {minus}1} for food and 0.006 to 61 Bq L{sup {minus}1} for drinks. Most of the other natural radionuclides in solid food were found to have contents below the minimum detectable activities (MDA). More samples in the leafy vegetable, tomato, carrot and potato categories contained detectable amounts of {sup 228}Ra than the meat, cereal, and fish categories, with concentrations up to 1.2 Bq kg{sup {minus}1} for the former categories and 0.35 Bq kg{sup {minus}1} for the latter categories. The {sup 238}U and {sup 226}Ra radionuclides were detectable in most of the water-based drink samples, and the {sup 228}Ra and {sup 210}Pb radionuclides were detectable in fewer water-based drink samples. The {sup 137}Cs contents in solid food were detectable in most of the solid food samples (reaching 0.59 Bq kg{sup {minus}1}), but in drinks the {sup 137}Cs contents were very low and normally lower than the MDA values. Nearly all the {sup 60}Co contents in food and drinks were below the MDA values and their contents were below those of {sup 137}Cs.

  1. 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.

  2. Radium-228 as an indicator of thorium-232 presence in a soil in Pernambuco, Brazil.

    PubMed

    Santos Júnior, J A; Amaral, R S; Silva, C M; Menezes, R S C; Bezerra, J D

    2009-06-01

    Radiometric measurements were taken in a small area of Pernambuco, Brazil, with the objective of monitoring the radium of the soil. For this, 78 soil samples were collected. The gamma analyses of the samples were carried out using HPGe. The values obtained for the (226)Ra varied from 14 to 367 Bqkg(-1) and for the (228)Ra from 73 to 429 Bqkg(-1). The ratio (228)Ra/(226)Ra varied from 1.0 to 7.0. Therefore, it is an indicator of an additional radioactivity source in this soil, maybe (232)Th, which will be further investigated in future studies.

  3. The uranium and thorium decay series nuclides in Mt. St. Helens effusives

    NASA Astrophysics Data System (ADS)

    Bennett, J. T.; Krishnaswami, S.; Turekian, K. K.; Melson, W. G.; Hopson, C. A.

    1982-08-01

    The concentrations of the radionuclides 238U, 230Th, 226Ra, 210Pb, 210Po, 232Th, 228Ra and 228Th and the abundances of major elements were determined in samples from all major eruptions of Mt. St. Helens from May 18, 1980 through June 21, 1981. During this time the effusives changed from plagioclase-phyric dacite to a more andesitic composition but the concentrations of U and Th series nuclides were measurably invariant. The average 232Th/ 238U weight ratio in the rocks is 2.4 and the 230Th/ 232Th activity ratio equals the 238U/ 232Th activity ratio indicating no fractionation of U from Th during magma genesis. 226Ra activity is in excess (˜40% on average) of its parent 230Th whereas 228Ra is in radioactive equilibrium with its parent 232Th, constraining the time of magma formation between 30 and 10 4 years prior to eruption. The 210Pb/ 226Ra activity ratios in the samples average 1.0, with a 20% scatter on either side, but allowing for volatile 210Pb loss at time of eruption excess 210Pb over 226Ra is inferred, indicating that the time of magma formation was within the last 150 years. 210Po was virtually absent in the samples immediately after eruption, indicating its total loss by volatilization during eruption. The quantity of 210Po volatilized during the May 18, 1980 event is estimated to be in the range of 300 Ci from the effusives and as much as 5000 Ci total including losses from heated slide material. The 222Rn activity volatilized should have been comparable to the 210Po activity released.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Lifetime of 6 Li40 K dimers near a Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Jag, Michael; Cetina, Marko; Lous, Rianne; Levinsen, Jesper; Petrov, Dmitry; Grimm, Rudolf

    2016-05-01

    We investigate the lifetime of bosonic dimers formed in a Fermi- Fermi mixture of 6 Li and 40 K atoms near a Feshbach resonance. Pure dimer samples are created from a Li-K mixture by ramping a magnetic field across the resonance and removing unbound atoms. We then perform lifetime measurements using both trapped high-density as well as expanding low-density samples after release from the trap. These measurements discriminate between the spontaneous and the collisional dimer decay. We further determine the dimer decay due to Li-LiK collisions in an atom-dimer mixture. Our measurements reveal a more than three-fold (five-fold) decrease in decay due to dimer-dimer (atom-dimer) collisions as the Feshbach resonance is approached. This observation is in good agreement with a theoretical prediction, which relates the decay rate to the probability of finding the colliding atoms within a short distance, and can mostly be explained by the increased fermionic character of the halo-dimer state together with Pauli blocking. We apply our model to combinations of other fermionic species to predict the dimer lifetime, which is an important parameter for their prospect towards realizing novel quantum phases. SFB FoQuS.

  10. 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.

  11. Rare earth elements in fly ashes created during the coal burning process in certain coal-fired power plants operating in Poland - Upper Silesian Industrial Region.

    PubMed

    Smolka-Danielowska, Danuta

    2010-11-01

    The subject of the study covered volatile ashes created during hard coal burning process in ash furnaces, in power plants operating in the Upper Silesian Industrial Region, Southern Poland. Coal-fired power plants are furnished with dust extracting devices, electro precipitators, with 99-99.6% combustion gas extracting efficiency. Activity concentrations ofTh-232, Ra-226, K-40, Ac-228, U-235 and U-238 were measured with gamma-ray spectrometer. Concentrations of selected rare soil elements (La, Ce, Nd, Sm, Y, Gd, Th, U) were analysed by means of instrumental neutron activation analysis (INAA). Mineral phases of individual ash particles were identified with the use of scanning electron microscope equipped with EDS attachment. Laser granulometric analyses were executed with the use of Analyssette analyser. The activity of the investigated fly-ash samples is several times higher than that of the bituminous coal samples; in the coal, the activities are: 226Ra - 85.4 Bq kg(-1), 40 K-689 Bq kg(-1), 232Th - 100.8 Bq kg(-1), 235U-13.5 Bq kg(-1), 238U-50 Bq kg(-1) and 228Ac - 82.4 Bq kg(-1).

  12. Measurements of radiation level in petroleum products and wastes in Riyadh City Refinery.

    PubMed

    Al-Saleh, F S; Al-Harshan, G A

    2008-07-01

    Recent concern has been devoted to the hazard arising from naturally occurring radioactive materials (NORM) in oil and gas facilities. Twenty-seven petroleum samples were collected from Riyadh Refinery. Fourteen samples were products and 13 were waste samples; three of them were scale samples and 10 were sludge samples. The specific radioactivities of (238)U, (232)Th, (226)Ra, (224)Ra, (40)K, and (235)U for all samples were determined using high-resolution gamma-ray spectrometry. The radium equivalent activity, radiation hazard indices and absorbed dose rate in air for all waste samples were estimated. The radon emanation coefficient of the waste samples was estimated. It ranged between 0.574 and 0.154. The age of two scale samples was determined and found to be 2.39 and 3.66 years. The chemical structure of the waste samples was investigated using X-ray florescence analysis (XRF) and Mg, Al, Si, S, Cl, Ca and Fe were found in all samples. From this study, it was noticed that the concentrations of the natural radionuclides in the petroleum wastes were higher than that of the petroleum products.

  13. 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.

  14. 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.

  15. Study of natural radioactivity in Mansehra granite, Pakistan: environmental concerns.

    PubMed

    Qureshi, Aziz Ahmed; Jadoon, Ishtiaq Ahmed Khan; Wajid, Ali Abbas; Attique, Ahsan; Masood, Adil; Anees, Muhammad; Manzoor, Shahid; Waheed, Abdul; Tubassam, Aneela

    2014-03-01

    A part of Mansehra Granite was selected for the assessment of radiological hazards. The average activity concentrations of (226)Ra, (232)Th and (40)K were found to be 27.32, 50.07 and 953.10 Bq kg(-1), respectively. These values are in the median range when compared with the granites around the world. Radiological hazard indices and annual effective doses were estimated. All of these indices were found to be within the criterion limits except outdoor external dose (82.38 nGy h(-1)) and indoor external dose (156.04 nGy h(-1)), which are higher than the world's average background levels of 51 and 55 nGy h(-1), respectively. These values correspond to an average annual effective dose of 0.867 mSv y(-1), which is less than the criterion limit of 1 mSv y(-1) (ICRP-103). Some localities in the Mansehra city have annual effective dose higher than the limit of 1 mSv y(-1). Overall, the Mansehra Granite does not pose any significant radiological health hazard in the outdoor or indoor. PMID:24185916

  16. 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.

  17. Natural radioactivity levels in building materials used in Egypt

    NASA Astrophysics Data System (ADS)

    Ahmad, Fawzia

    All building materials contain various amounts of radioactive nuclides. The levels of natural radioactivity in 43 selected typical building materials used in the construction of walls, windows and doors were determined. For the first time, the radioactivity of iron was measured, revealing the existence of 60Co. A shielded high-purity germanium detector was used to measure the abundance of 226Ra, 232Th and 40K. The materials examined in this work showed radioactivity levels below the limit estimated from radium equivalent activity for acceptable radiation doses attributable to building materials, except for the fact that one gypsum sample showed higher levels of activity than average world levels. The studied building materials were classified according to the radium equivalent activities, which varied from highest to lowest levels as follows: clay, cement, brick, gypsum except from Abu-Zaabal, sand, wood, iron, glass and hydrated lime The existence of the 137Cs isotope in some building materials was confirmed and its concentration levels were determined (ranging from 0.04 to 21.156 Bq kg-1). The alpha-activity of radon was measured in a number of building materials using CR-39 detectors.

  18. Measurements of natural radioactivity and the resulting radiation doses from commercial granites.

    PubMed

    Aydarous, A Sh; Zeghib, Sadek; Al-Dughmah, Mohammed

    2010-12-01

    Saudi Arabia is becoming a relatively large market for local and foreign marble and granite use in dwellings. Due to increasing concern about environmental radiological protection, different types of locally widely used granite tiles were collected from different suppliers in the Jeddah province, Saudi Arabia. The analysis for these granite tiles for gamma radiation was conducted by means of a high-resolution HPGe gamma-spectroscopy system. The activity concentrations of (232)Th, (226)Ra and 40K in the selected granite samples ranged from 4.9 to 144, 9.7 to 133 and 168 to 1806 Bq kg(-1), respectively. The data were compared with other granite types and building materials used all over the world. The absorbed dose rates, effective dose rates, radium equivalent activities as well as the radiation hazard indices were estimated. The radium equivalent activities (Ra(eq)) are lower than the limit of 370 Bq kg(-1) set by the Organisation for Economic Cooperation and Development (Exposure to radiation from the natural radioactivity in building materials. Report by a Group of Experts of the OECD, Nuclear Energy Agency, OECD, Paris, 1979) except in three samples.

  19. 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.

  20. Radiological significance of building bricks in Pakistan.

    PubMed

    Khan, K; Aslam, M; Orfi, S D; Khan, H M

    2001-01-01

    Baked clay bricks samples were collected from both urban and rural areas of the North West Frontier Province of Pakistan and natural radioactivity due to 40K, 226Ra and 232Th has been measured in these samples. The specific absorbed dose rates due to natural radioactivity emanating from the walls, floors and ceilings of the typical model rooms made of these building bricks have been calculated applying the mesh size adaptive volume integral methodology. The occupancy factor, representing the weighted average of all the population in the country, was taken to be 0.3 in this study. The values of estimated annual effective dose rates for whole body were found to be 0.38 and 0.35 mSv.y(-1) for the two types of model rooms. These values are smaller than those predicted by UNSCEAR for normal background areas. Thus the building bricks analysed in this study do not pose any significant health problem to the population.

  1. 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.

  2. 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.

  3. 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

  4. Study of some natural radionuclides near the Saudi coast of the Arabian Gulf

    NASA Astrophysics Data System (ADS)

    Al-Kheliewi, A. S.; Shabana, S. I.; Farouk, M. A.

    2012-06-01

    There is no authoritative study on marine radioactivity in the Arabian Gulf of Saudi Arabia nor is there any trusty measurements in the Red Sea's side of Saudi Arabia as well. Different surface sediment samples have been collected in three coastal areas from the the Saudi side of the Arabian Gulf‥ Those samples were collected at different depths varying from 5 to 25 meters, depending on the surface type and its geological composition, from 11 locations along the gulf coast. Activity concentrations of measured radionuclides 40K, 238U, 235U, 230Th, 226Ra, 232Th, 228Th, and 228Ra were: 23.69-253.3, 23.11 - 39.76, 1.05 - 1.65, 0.20 - 1.83, 1.99 - 9.46, 0.12 - 0.95, 0.11 - 1.15, 1.25 - 10.26 Bq/Kg respectivelty. All natural radionuclides measurements fall within the international accepted limits.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Radionuclide concentrations in soil and lifetime cancer risk due to gamma radioactivity in Kirklareli, Turkey.

    PubMed

    Taskin, H; Karavus, M; Ay, P; Topuzoglu, A; Hidiroglu, S; Karahan, G

    2009-01-01

    The objective of this study is to evaluate and map soil radionuclides' activity concentrations and environmental outdoor gamma dose rates (terrestrial and cosmic) in Kirklareli, Turkey. The excess lifetime cancer risks are also calculated. Outdoor gamma dose rates were determined in 230 sampling stations and soil samples were taken from 177 locations. The coordinates of the readings were determined by the Global Positioning System (GPS). The outdoor gamma dose rates were determined by Eberline smart portable device (ESP-2) and measurements were taken in air for two minutes at 1m from the ground. The average outdoor gamma dose rate was 118+/-34nGyh(-1). Annual effective gamma dose of Kirklareli was 144microSv and the excess lifetime cancer risk of 5.0x10(-4). Soil samples were analyzed by gamma spectroscopy. The average 226Ra, 238U, 232Th, 137Cs, and 40K activities were 37+/-18Bqkg(-1), 28+/-13Bqkg(-1), 40+/-18Bqkg(-1), 8+/-5Bqkg(-1) and 667+/-281Bqkg(-1), respectively. The average soil radionuclides' concentrations of Kirklareli were within the worldwide range although some extreme values had been determined. Annual effective gamma doses and the excess lifetime risks of cancer were higher than the world's average. PMID:19038480

  10. Determination of the natural and anthropogenic radioactivity in the soil of Gilgit--a town in the foothills of Hindukush range.

    PubMed

    Ali, Manzoor; Wasim, Mohammad; Arif, Mohammad; Zaidi, Jamshed Hussain; Anwar, Yasir; Saif, Farhan

    2010-05-01

    The activity concentration of terrestrial (226Ra, 232Th, and 40K) and anthropogenic gamma-emitting radionuclide (137Cs) have been analyzed in 48 soil samples collected from Gilgit, a famous city for mountaineers and tourists in northern Pakistan, at an average altitude of 1,550 m, using gamma-ray spectrometry. The data analysis includes descriptive statistics, radium equivalent activity and its principal component analysis, air absorbed dose rate, annual effective dose rate, and collective effective dose equivalent. It is found that the level of cosmic exposure is high in Gilgit relative to the world average values, but the average outdoor annual effective dose rate from terrestrial radionuclides is lower as compared to its value in the soil of Punjab, Pakistan, and the world average values found in United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) for the general public. The median annual effective dose rate produced by 137Cs was 0.11 microSv y-1. PMID:20386195

  11. 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.

  12. Radiological impacts of natural radioactivity from soil in Montenegro.

    PubMed

    Antovic, N M; Svrkota, N; Antovic, I

    2012-02-01

    Soil samples from Montenegro were analysed by the HPGe detector with 40 % of relative efficiency, for radioactivity due to (226)Ra, (232)Th and (40)K. The average activity concentrations have been found to be 39.9, 43.5 and 437.6 Bq kg(-1), respectively, i.e. in accordance with those in the other South European countries. In order to evaluate the health hazard, radium equivalent activity, absorbed dose rate, annual effective dose rate, external hazard index, annual gonadal dose equivalent and excess lifetime cancer risk (CR) have been calculated. The excess lifetime CR (× 10(-3)) had a range from 0.12 to 0.79, with an arithmetic mean of 0.27, which is in accordance with the global average. Mean gonadal dose equivalent was higher than the world average, and one location was found with the radium equivalent activity >370 Bq kg(-1), i.e. with the external hazard index higher than unity, which means the radiation hazard is not negligible.

  13. 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.

  14. 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

  15. 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 (<