Skeletal dosimetry of injected 226RA in young adult beagles

International Nuclear Information System (INIS)

Lloyd, R.D.; Mays, C.W.; Atherton, D.R.

1986-01-01

Revised equations are presented for the skeletal dose to young adult beagles from 226 Ra injection. For 0.1 kg of skel/kg body and given 1 μCi 226 Ra/kg with 210 Pb/ 226 Ra = 0.05, the average skeletal dose in rad at 6 yr is 226 Ra = 1200, 222 Rn -> 214 Po = 1050, injected 210 Pb = 56 and 210 Pb from Rn decay in bone = 22. For a Pb/Ra ratio = 0.4, dose from injected 210 Pb is about 20% of that from 226 Ra -> 214 Po. A similar but not numerically indentical relationship obtains for ingested 226 Ra, so the dose from 210 Pb should be included in any study of 226 Ra effects. (orig.)

Distribution of 226Ra and 228Ra in drinking water and dose assessment

International Nuclear Information System (INIS)

Ajay Kumar; Sugandhi, S.; Usha, N.; Rupali, K.; Gurg, R.P.

2002-01-01

The radioactivity concentrations of 226 Ra and 228 Ra have been analysed in 123 drinking water samples received from different regions of India. The maximum concentrations of 226 Ra and 228 Ra in drinking water are 8 mBq/l and 11.5 mBq/l respectively. The higher doses due to intake of 228 Ra through drinking water suggests that 228 Ra should also be measured in the assessment of ingestion dose to the population. The estimated committed effective doses range from 0.082 to 2.45 μSv/year and from 1.53 to 8.81 μSv/year for the ingestion of 226 Ra and 228 Ra respectively. (author)

224Ra and 226Ra experimentally induced dental changes in rats

International Nuclear Information System (INIS)

Reichart, P.A.; Althoff, J.; Eckhardt, W.; Rippel, W.

1979-01-01

Sprague-Dawley rats received intragastrically a single dose of 226 Ra or 224 Ra once weekly for 21 weeks. During this period the animals of both groups were thus exposed to comparable doses. After 12 weeks, a shortening of the maxillary incisors was observed, and this progressed during the course of the 55-week experiment. Radiologically, a loss of pulpal transparency and an apical irregular opacity in the maxillary incisors were demonstrable. Histologically, dysplastic changes of the maxillary incisors and multiple resorptions at the cemento-enamel junction of the molars were seen. The observed alterations were more pronounced in the 226 Ra group than in the 224 Ra treated group. The experimentally induced resorptions were comparable to those observed in patients who had incorporated 224 Ra or 226 Ra. Clinical, radiological, histological, γspecrometrical, and autoradiographical findings, as well as dose-estimations, are described. (author)

Chemical and mineralogical characterization of waste generated in the petroleum industry and its correlation with 226Ra and 228Ra contents

International Nuclear Information System (INIS)

Gazineu, M.H.P.; Hazin, C.H.; Godoy, J.M.O.

2004-01-01

Scales and sludge are commonly formed during oil and gas extracting and processing operations. They usually appear when injection and formation water with different chemical characteristics come into contact. When the produced water is brought to the surface alongside with the oil, the precipitate can be deposited on the walls of tubing and equipment, forming the so-called scales. Otherwise they can also accumulate in the form of sludge on the bottom of storage tanks, separators, and other equipment. Radium is the main radionuclide brought to the surface with oil and produced water and it co-precipitates with barium forming complex compounds of sulfates, carbonates and silicates. These compounds are the main constituents of scale and sludge. The objective of this work was to relate the radium content of scales and sludge to their chemical and mineralogical composition. Samples were taken from a PETROBRAS unit in the State of Sergipe, in Northeast Brazil. They were collected either from the inner surface of water pipes or from containers stored in the waste storage area of the unit. Oil was separated from the solid material in a Soxhlet extractor equipment by using aguarras as solvent. The concentrations of 226 Ra and 228 Ra were determined by gamma spectrometry. The mineralogical and the chemical composition of the samples were determined by x-ray diffraction and x-ray fluorescence, respectively, and used to characterize the samples as scales or sludge. The results have shown that scales are mainly formed by BaSO 4 and CaCO 3 while sludge has a higher content of SiO 2 and FeO 3 than that observed on the scale samples. The measured activity concentrations of 226 Ra and 228 Ra are strongly correlated for both kinds of samples. Based on the 228 Th/ 228 Ra ratio, ages between one and five years were estimated for the material stored in the waste area. (author)

Alpha-particle doses to human organs and tissues from internally-deposited 226Ra and 228Ra

International Nuclear Information System (INIS)

Keane, A.T.; Schlenker, R.A.

1981-01-01

Estimation of radiation doses to the soft tissues from internally-deposited 226 Ra and 228 Ra is relevant to an investigation of soft-tissue malignancies in radium-exposed persons being conducted at the Center for Human Radiobiology. Alpha-particle doses in a 50-year period following a single injection of 226 Ra or 228 Ra are presented for 31 soft tissues and organs of the adult human. The dose estimates were derived from the ICRP alkaline earth model fitted to data on retention of 226 Ra in soft tissues and bone, combined with reported ratios of 226 Ra to Ca in soft tissue and bone at natural levels and the distribution of Ca in the tissues of Reference Man (ICRP23). The median of the 31 organ and tissue doses from the α-particles of 226 Ra itself is 0.08 rad per injected μCi. An additional average dose of 0.01 rad per μCi 226 Ra daughter products produced in soft tissue or transferred from bone to soft tissue. Soft-tissue doses from α-particles of the 228 Ra decay series are about six times those from 226 Ra α-particles for equal injected activities of 228 Ra and 226 Ra, with the assumption that 228 Ra daughter products do not transfer from the organ in which they are produced. The 50-year dose to the red marrow of bone from α-particles originating in bone is 0.55 rad per μCi 226 Ra injected and 1.0 rad per μCi 228 Ra injected. For ingestion by dial painters of luminous compound containg 226 Ra or 228 Ra with a daughter-to-parent activity ratio of 0.5, the dose to the mucosal alyer of the lower large intestine from α-particles originating in the gut contents is about 0.1 rad per μCi systemic intake of 226 Ra or 228 Ra

226Ra chronology of a coastal marine sediment

International Nuclear Information System (INIS)

Koide, M.; Bruland, K.; Goldberg, E.D.

1976-01-01

Unsupported 226 Ra (tsub (1/2) = 1620 years) in marine sediments can provide a basis for measuring rates of accumulation of the order of centimeters per thousand years. The excess radium apparently enters the sediments incorporated in phytoplankton. The sensitivity of the method depends upon the initial value of the unsupported 226 Ra and of the value of 230 Th, a parent of 226 Ra, in the sedimentary components. 226 Ra dating was applied to a sediment taken from the slope of the San Clemente Basin in the Southern California coastal region. Rates of sedimentation over two half-lives of the nuclide were found to be either 5.2 or 5.3 cm/1000 years depending upon which of two models for the geochronology is used. One model assumes that the 230 Th brings to the deposit an amount of 226 Ra in equilibrium with it. The other is based upon the growth of the 226 Ra from the 230 Th in the sedimentary components. 238+239 Pu and 210 Pb levels in the upper strata indicated sedimentation rates of the order of 100-500 cm/1000 years, i.e. much faster accumulations. It is suggested that these derived rates are spurious and reflect bioturbative activities of surface-living organisms. (Auth.)

226Ra and 228Ra in ground water of the Cambrian-Ordovician Aquifer System in northern Illinois

International Nuclear Information System (INIS)

Gilkeson, R.H.; Holtzman, R.B.

1982-01-01

Over a large region of Illinois, ground water of the Cambrian-Ordovician Aquifer System exceeds the US EPA drinking water standard of 5 pCi/L for the combined concentration of 226 Ra and 228 Ra. 226 Ra concentrations range from 226 Ra is the geochemistry of uranium in the ground-water flow system, while the 228 Ra activity in ground water which ranges from 232 Th-bearing minerals in the aquifer strata. The comparison of recent analyses to historical data gathered over the last 20 years indicates that, with few exceptions, 226 Ra and 228 Ra activities in ground water have remained constant. The combined concentrations of the two nuclides in ground water of the aquifer system ranged from 226 Ra concentrations were high (greater than or equal to 10 pCi/L), those of 228 Ra were low (less than or equal to 2 pCi/L), but, with few exceptions, in regions where 228 Ra concentrations were high, those of 226 Ra were also high. The range of values raises questions concerning the validity of the US EPA regulation which requires analysis for 228 Ra only when the concentration of 226 Ra exceeds 3.0 pCi/L

Distribution and flux of 226Ra and 228Ra in the Amazon River estuary

International Nuclear Information System (INIS)

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

1985-01-01

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

Late excretion rates of 226Ra and 210Pb following occupational or iatrogenic exposure. I. 226Ra

International Nuclear Information System (INIS)

Holtzman, R.B.; Sha, J.Y.; Markun, F.

1982-01-01

The urinary and fecal excretion rates of 226 Ra have been determined for 53 subjects who had been exposed to 226 Ra; 25 had been radium dial painters, 16 were iatrogenic (medical) cases and 12 were former radium chemists. The mean coefficient of elimination, CE (fraction of body content excreted annually), was significantly lower for the medical cases than for dial painters. The mean ratio of urinary-to-fecal excretion rates was 3.0 +- 0.7%

Determination of 226Ra by alpha spectrometry of liquid scintillation

International Nuclear Information System (INIS)

Nobrega, A.W.; Sachett, I.A.; Hespanhol, E.C.B.

1987-01-01

The determination of 226 Ra in environmental samples using alpha spectrometry in liquid scintilation is studied. The Radon 1-2 emanation method and 226 Ra separation process of other radionuclides alpha emissors are analyzed. The use of 226 Ra coprecipitation with barium sulphate is evaluated. (M.J.C.) [pt

Effects of barium chloride treatment of uranium mill tailings and ore on radon emanation and 226Ra levels. Progress report

International Nuclear Information System (INIS)

Ibrahim, S.A.; Flot, S.L.

1983-01-01

The purpose of this study was to investigate the effect of barium chloride treatments on: reduction of 222 Rn emanation from mill wastes; reduction of 226 Ra levels in wastewater; and decreased leachability of 226 Ra from mill wastes. Baseline 226 Ra concentrations were determined for ore and tailings as well as radon emanation fractions. Uranium ore was treated with soluble barium at concentrations of 10, 25, 50, and 100 mg per litre of slurry. The leach-liquor declined in 226 Ra concentration by as much as 50%. When soluble potassium as well as barium was used in the treatment process at equal concentrations of 10, 25, 50, and 100 mg per litre of slurry, a similar reduction was observed. No significant difference was noted between the two treatment regimes. An accelerated leaching experiment was performed on the ore treated with barium chloride. All treatment groups except that treated with 10 mg of soluble barium per litre of slurry showed significant decreases in leachability. Available 222 Rn (corresponds with radon emanation fraction) was measured in treated and untreated ore. Ore treated with concentrations of Ba ++ up to 1.00 mg per gram of ore did not show a statistically significant reduction in available 222 Rn, however when potassium sulfate was also added, a significant decline was noted. This study suggests that barium chloride treatments reduce radon emanation from mill wastes and reduce 226 Ra levels in wastewater. Leachability of 226 Ra from treated samples decreased markedly. 19 references, 8 figures, 7 tables

Radiochemical determination and separation or total radium, 226Ra and 224Ra

International Nuclear Information System (INIS)

Suarez, J. A.; Gonzalez, J. A.; Pablo, M. A. de

1987-01-01

Radiochemical purification and separation of radium has been carried out and the determination of total radium solubilized in aqueous samples has been studied assuming that all the alpha emitters of the sample have their origin in the 226Ra and elements of its desintegration chain. Also, the activities of 22Ra and 226 Ra have been evaluated separately doing a measurement after the chemical separation of the radium and another one 10 days after. (Author) 9 refs

Behavior of 226Ra in the Mississippi River mixing zone

Science.gov (United States)

Moore, Daniel G.; Scott, Martha R.

1986-12-01

The behavior of 226Ra in the Mississippi River mixing zone is strongly nonconservative and includes desorption similar to that reported for the Hudson, Pee Dee, and Amazon rivers. However, dissolved and desorbed 226Ra 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 226Ra 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 226Ra (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 226Ra. The dissolved 226Ra river water end-member (9.6 dpm per 100 L) is higher than in surface seawater. The annual contribution of 226Ra to the ocean from the Mississippi River is 3.7 × 1014 dpm/yr, based on data from three cruises. Evidence of flux of 226Ra 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.

Determination of 226 Ra and 228 Ra in mineral spring waters of the Aguas da Prata region

International Nuclear Information System (INIS)

Oliveira, J. de.

1993-01-01

Concentration levels of 226 Ra and 228 Ra have been analysed in most of the mineral spring waters available in the Aguas da Prata region. The 226 Ra and 228 Ra were determined by coprecipitation with barium sulphate. The 226 Ra was determined by gross alpha counting of the Ba(Ra)SO 4 precipitate. The determination of 228 Ra was done by measuring the gross beta activity of the same precipitate. Both measurements were carried out in a low background gas flow proportional counter. Dose calculations were performed in order to evaluate the relative importance of such radionuclides to the radiation exposure due to the ingestion of these waters. Based upon measured concentrations, committed effective doses up to 5.5 x 10 -1 mSv/y and 1.0 x 10 -2 mSv/y were observed for 226 Ra and 228 Ra, respectively. These results show that 226 Ra is the main contributor to radiation exposure. (author)

Automated measurement of 224Ra and 226Ra in water

International Nuclear Information System (INIS)

Dimova, N.; Burnett, W.C.; Horwitz, E.P.; Lane-Smith, D.

2007-01-01

We present a new simple approach for automated, non-destructive measurement of the alpha-emitting radium isotopes ( 223 Ra, 224 Ra, and 226 Ra) in water based on the emanation of their respective radon daughters ( 219 Rn, 220 Rn, and 222 Rn). The method combines the high adsorption uptake of MnO 2 Resin for radium (K d =2.4x10 4 ml/g) over a wide pH range with the simplicity of the activity registration using a commercial radon-in-air analyzer (RAD7, DURRIDGE Company, Inc). Radium is first adsorbed onto the MnO 2 Resin by passing a water sample through the resin packed in a gas-tight glass cartridge. The same cartridge is then connected to the radon analyzer via a simple tubing system to circulate air through the resin and a drying system. The efficiency of the proposed system is determined by running standards prepared in the same manner. Our results indicate that the efficiency for 226 Ra is >22% if both 218 Po and 214 Po counts are collected. This is comparable with typical efficiencies for alpha spectrometry but with much less sample preparation. We estimate that an MDA of 0.8 pCi/L for 226 Ra may be obtained with this new approach using a 1 L water sample and less than 4 h of counting

Production of Ac-225 for cancer therapy by photon-induced transmutation of Ra-226.

Science.gov (United States)

Melville, G; Meriarty, H; Metcalfe, P; Knittel, T; Allen, B J

2007-09-01

The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. The production of Ac-225 has been achieved using bremsstrahlung photons from an 18 MV medical linear accelerator (linac) to bombard a Ra-226 target. A linac dose of 2800 Gy produced about 64 microCi of Ra-225, which decays to Ac-225. This result, while consistent with the theoretical calculations, is far too low to be of practical use. A more powerful linac is required that runs at a higher current, longer pulse length and higher frequency for practical production. This process could also lead to the reduction of the nuclear waste product Ra-226.

Research over the extraction process in order to simulate 226Ra and Unat radionuclides migration in uranium waste dumps

International Nuclear Information System (INIS)

Bragea, Mihaela; Toro, Laszlo; Cristache, Carmen

2008-01-01

To simulate the phenomenon of migration availability of radioactive elements in uranium waste product from waste dump into the environment it was taken into account the Ciudanovita, Romania area with its uranium waste dumps. It were made studies through experiments of static extraction in agitation pot (static regime), which allow to pursue the evolution of contaminants along a specific period of time. It was accomplish a study about sorption and adsorption process on the geological environment (clay). It was observed that 226 Ra and U nat transition through the sorption and adsorption processes were induced by the type of clay (due to variable solubility of clay and the physics and chemical status of 226 Ra and U nat into the clay) and the time interval until the water contacts the clay. The concentration measurements of radionuclides into different dimension of clay particles were made to give pertinent information about the way of chosen the repair strategies for the studied site. The present work is based mainly on this research direction: optimization and improvement of the performances obtained from the geo-chemical processes investigation methods in the waste dumps and the surrounding geological structures to isolate them, in order to reduce the negative environmental impact. Measurements of the two radionuclides concentrations in particles with different dimensions were made to supply accurate information regarding the selection of remediation strategies for the dumpsite in study. (author)

Preparation of 227Ac/223Ra by neutron irradiation of 226Ra

International Nuclear Information System (INIS)

Ekaterina Kukleva; Jan Kozempel; Martin Vlk; Petra Micolova; Dusan Vopalka

2015-01-01

Radium-223 is a prospective alpha-emitter for targeted radionuclide therapy. Although 223 Ra is formed naturally by the decay of 235 U, for practical reasons its preparation involves neutron irradiation of 226 Ra. The β - decay of the 227 Ra (T ½ = 43 min) produced via 226 Ra(n,γ) 227 Ra reaction leads to 227 Ac, a mother nuclide of 227 Th and subsequently 223 Ra. Radium target material is generally available in multigram quantities from historical stock. The main aim of this study was to experimentally as well as theoretically evaluate and verify the available literature data on production of 227 Ac/ 223 Ra. According to the data obtained from the γ-spectra, the approximate yield values were determined and effective cross section value for the 227 Ac production was calculated to 14 ± 4 b. (author)

226Ra concentrations in some Illinois well waters

International Nuclear Information System (INIS)

Holtzman, R.B.; Gilkeson, R.H.

1982-01-01

226 Ra concentrations are reported for the waters from deep wells in 43 communities in Illinois. The concentrations range from 0.08 to 20.6 pCi/L. The effectiveness of additives (nitric acid or EDTA) in keeping the 226 Ra in solution in the samples is discussed

Behavior and distribution of 226Ra and 228Ra in the east coast of Peninsular Malaysia marine environment

International Nuclear Information System (INIS)

Nurrul Assyikeen Mohd Jaffary; Zal Uyun Wan Mahmood; Zaharudin Ahmad; Yii, Mei Wo; Kamarozaman Ishak

2010-01-01

The present distributions of 226 Ra, 228 Ra and activity ratios of 228 Ra/ 226 Ra covering the east coast of Peninsular Malaysia were studied. Sediment core samples were collected at 10 identified stations with the thickness of water column between 14 - 72 m depth during the cruise conducted in 2008. Activity concentrations of 226 Ra and 228 Ra in sediment cores of the studied area were in the range of 18.95 ±4.25 Bq/ kg to 46.48 ± 6.41 Bq/ kg dry wt. and 35.50 ± 7.50 Bq/ kg to 77.10 ±11.37 Bq/ kg dry wt., respectively. Meanwhile, the calculated activity ratios of 228 Ra/ 226 Ra were varied mostly 1.48 to 2.24. The finding showed that there has relationships between 226 Ra, 228 Ra and oceanographic parameters which are can be attributed for better understanding of its transport processes and behavior in the east coast of Peninsular Malaysia marine environment. (author)

Effective 226Ra-content of some Hungarian building materials

International Nuclear Information System (INIS)

Toth, A.; Feher, I.

1976-01-01

The aim of the work was to analyse the effective 226 Ra content of building- and back filling materials used in Hungary. The quantity of radon was determined by ionization chambers connected to vibrating-reed electrometers, as well as by a scintillation radon counter. The radon measuring instruments were calibrated by known 222 Rn quantities given off from standard RaCl 2 solutions. The overall uncertainty of the data obtained is estimated as being 25%. The minimum measurable effective 226 Ra concentration due to a 10 4 g building material source is calculated as 16 fCi/g for the ionization chambers and 8 fCi/g for the scintillation counter. 68 building material samples and 11 backfill (concrete made by fly-ashes) samples have been studied and it has been found, that the effective 226 Ra contents of the tested building materials are 2 to 9 times greater than those found in the Soviet Union though none exceeds the recommended 600 fCi/g level. Among the back filling materials made with fly-ash the maximum 226 Ra content was 3300 fCi/g. The effective 226 Ra content measurements are well suited for a priori radon escape qualification of building materials. (K.A.)

The flux of 226Ra from estuarine and continental shelf sediments

International Nuclear Information System (INIS)

Li, Y.H.; Mathieu, G.; Biscaye, P.; Simpson, H.J.

1977-01-01

A pronounced desorption phenomenon of 226 Ra from sediment was observed in the Hudson River estuary. Mass balance calculations indicate that the desorption of 226 Ra from the river-borne sediment in estuarine environment is an important source of 226 Ra to the oceans. (Auth.)

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

International Nuclear Information System (INIS)

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

2010-01-01

Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While 228 Ra and 226 Ra are usually measured using gamma spectrometry, short-lived Ra isotopes ( 224 Ra and 223 Ra) 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 226 Ra, 228 Ra, 224 Ra, 223 Ra activities measured using low-background gamma spectrometry in standard samples, in water samples collected in the vicinity of our laboratory (La Palme and Vaccares lagoons, France) but also in seawater samples collected in the plume of the Amazon river, off French Guyana (AMANDES project). The 223 Ra and 224 Ra 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 224 Ra activities are similar for the two techniques. RaDeCC is more sensitive for the detection of low 223 Ra activities. Gamma spectrometry thus constitutes an alternate method for the determination of short-lived Ra isotopes.

The distribution of 226Ra in the Atlantic Ocean

International Nuclear Information System (INIS)

Broecker, W.S.; Goddard, J.; Sarmiento, J.L.

1976-01-01

Based on results obtained during the GEOSECS program the primary features of the distribution of 226 Ra in the Atlantic Ocean can be defined. Outside the Antarctic no significant variation has been found in the 226 Ra content of surface waters. Eighty samples yield an average of 7.4 dpm/100 kg (normalized to a salinity of 35.00%). Deep waters in the central Atlantic have 226 Ra contents several dpm/100 kg higher than expected from the mixing of Antarctic Bottom Water (21.3 dpm/100 kg) and basal North Atlantic Deep Water (10.3 dpm/100 kg). These excesses correlate well with deficiencies in O 2 and excesses in SiO 2 . The intermediate water 226 Ra maximum in the South Atlantic is associated with the inflow of low-oxygen Circumpolar Intermediate Water beneath the Antarctic Intermediate Water. (Auth.)

A theoretical model for the production of Ac-225 for cancer therapy by neutron capture transmutation of Ra-226.

Science.gov (United States)

Melville, G; Melville, P

2013-02-01

Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. We are investigating the reduction of radium by transmutation by bombarding Ra-226 with high-energy neutrons from a neutron source to produce Ra-225 and hence Ac-225, which can be used as a generator to produce Bi-213 for use in 'Targeted Alpha Therapy' for cancer. This paper examines the possibility of producing Ac-225 by neutron capture using a theoretical model in which neutron energy is convoluted with the corresponding neutron cross sections of Ra-226. The total integrated yield can then be obtained. This study shows that an intense beam of high-energy neutrons could initiate neutron capture on Ra-226 to produce Ra-225 and hence practical amounts of Ac-225 and a useful reduction of Ra-226. Copyright © 2012 Elsevier Ltd. All rights reserved.

Techniques for precise mapping of 226Ra and 228Ra in the ocean

International Nuclear Information System (INIS)

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

1985-01-01

Improvements in the analyses of 226 Ra and 228 Ra in seawater made possible by better extraction and processing techniques reduce significantly the errors associated with these measurements. These improvements and the extensive sampling for Ra isotopes conducted on the TTO North Atlantic Study should enable us to use the distribution of 228 Ra to study mixing processes on a 3-15 year time scale in both the upper and deep North Atlantic. The 228 Ra profiles already analyzed show a closer resemblance to GEOSECS tritium data than to TTO tritium data in the upper ocean. This is because the transient tracer tritium was responding on a 10-year time scale during GEOSECS and a 20-year time scale during TTO. The steady state tracer 228 Ra should always respond on a time scale of 8 years. Thus the 228 Ra data obtained on TTO should provide a means to extend the features of the GEOSECS tritium field to the regions of the TTO study. The 226 Ra data are of high enough quality to identify features associated with different water masses. Changes in the positions of the deep-water masses since the GEOSECS cruise are revealed by the 226 Radata

Determination of /sup 226/Ra by alpha spectrometry of liquid scintillation

Energy Technology Data Exchange (ETDEWEB)

Nobrega, A W; Sachett, I A; Hespanhol, E C.B.

1987-07-01

The determination of /sup 226/Ra in environmental samples using alpha spectrometry in liquid scintilation is studied. The Radon/sup 1-2/ emanation method and /sup 226/Ra separation process of other radionuclides alpha emissors are analyzed. The use of /sup 226/Ra coprecipitation with barium sulphate is evaluated. (M.J.C.).

Transfer of 226Ra, 228Ra, 210Pb and 210Po in aquatic organisms and food chain

International Nuclear Information System (INIS)

Yang Xiaotong; Weng Detong; Chen Wenyin; Chen Xiuyun; Chen Jixi; Zhao Shimin

1998-01-01

Objective: To find out the transfer regularities of 226 Ra, 228 Ra, 210 Pb and 210 Po, which are natural radionuclides in the aquatic organisms and food chain. Methods: Large amount of breed of representative aquatic products and their living waters and sediments were collected and treated according to routine experimental procedures. The contents of 226 Ra, 228 Ra, 210 Pb and 210 Po were detected in each sample. Measured data were analyzed statistically and pairwise comparisons were made to determine the differences between groups. Results: 226 Ra, 228 Ra and 210 Pb were mainly deposited in the bones (or shells), their concentration factors (CF) ranged from 10 2 to 10 3 ; the CF ranged only from 10 0 to 10 2 in the flesh. 210 Po was mainly deposited in the soft tissues, CF ranged from 10 2 to 10 4 ; especially in the stomachs and intestines of fishes, the value reached 10 4 . The cooking process did not impinge significantly on the transfer of 226 Ra, 228 Ra and 210 Pb in the food chain (P>0.05), but did significantly influence the transfer of 210 Po, especially in the freshwater fishes and shrimps. Paired comparison test of the activities between raw flesh and cooked flesh showed very significant difference (P 226 Ra, 228 Ra, 210 Pb and 210 Po. Even though the bones (or shells) of aquatic organisms contained relatively higher levels of 226 Ra, 228 Ra and 210 Pb, the cooking process does not significantly increase the radioactive contents in the foodstuffs. However, the cooking process does significantly influence the transfer of 210 Po. It does significantly increase the content of 210 Po in foodstuffs

A new determination method of 226Ra, 224Ra, and 228Th in water

International Nuclear Information System (INIS)

Horiuchi, Kimiko; Murakami, Yukio.

1981-01-01

A new method for the determination of 226 Ra, 224 Ra and 228 Th in water samples is described. It consists of extraction of 222 Rn and 220 Rn into a scintillator-toluene solution in equilibrium with 226 Ra and 224 Ra and the application of integral counting techniques with a liquid scintillation counter. One liter water sample, weakly acidified with hydrochloric acid, is transferred to a glass bottle, and vigorously bubbled with a stream of nitrogen to expel any radon or thoron in the water sample. Twenty five ml of the scintillator-toluene solution is added to the bottle (time is recorded). The bottle is stoppered with a Teflon stopper and kept at an upside-down position for a given period of time (usually 4 -- 16 days) to allow radon and thoron in partial equilibrium with their parent nuclides. Then, the sample system is vigorously shaken for 2 m and the organic layer is gently transferred to a counting vial through a specially devised transferring tube which is connected to the bottle. The initial counting time is set at 4 h after the separation of organic layer. The measurements are repeated 3 times each immediately and after 106 h from the initial counting time. From these results, the integral counting rates of radon and thoron at the initial counting time are easily obtained. The activities of 226 Ra, 224 Ra and 228 Th in the water sample are calculated from these integral counting rates by the proposed formulas. Some data on the 226 Ra and 224 Ra contents of mineral springs are presented. The lowest detection limits for 226 Ra and 224 Ra were 1.10 x 10 -12 and 1.47 x 10 -9 Ci, respectively. The present method is rapid, easy and accurate and eliminates a time-consuming sealing of the sample in Curie bottle and tedious procedure to transfer the sample gas through a vacuum system to the detector. (author)

The 226Ra-Ba relationship in the North Atlantic during GEOTRACES-GA01

Science.gov (United States)

Le Roy, Emilie; Sanial, Virginie; Charette, Matthew A.; van Beek, Pieter; Lacan, François; Jacquet, Stéphanie H. M.; Henderson, Paul B.; Souhaut, Marc; García-Ibáñez, Maribel I.; Jeandel, Catherine; Pérez, Fiz F.; Sarthou, Géraldine

2018-05-01

We report detailed sections of radium-226 (226Ra, T1/2 = 1602 years) activities and barium (Ba) concentrations determined in the North Atlantic (Portugal-Greenland-Canada) in the framework of the international GEOTRACES program (GA01 section - GEOVIDE project, May-July 2014). Dissolved 226Ra and Ba are strongly correlated along the section, a pattern that may reflect their similar chemical behavior. Because 226Ra and Ba have been widely used as tracers of water masses and ocean mixing, we investigated their behavior more thoroughly in this crucial region for thermohaline circulation, taking advantage of the contrasting biogeochemical patterns existing along the GA01 section. We used an optimum multiparameter (OMP) analysis to distinguish the relative importance of physical transport (water mass mixing) from nonconservative processes (sedimentary, river or hydrothermal inputs, uptake by particles and dissolved-particulate dynamics) on the 226Ra and Ba distributions in the North Atlantic. Results show that the measured 226Ra and Ba concentrations can be explained by conservative mixing for 58 and 65 % of the samples, respectively, notably at intermediate depth, away from the ocean interfaces. 226Ra and Ba can thus be considered conservative tracers of water mass transport in the ocean interior on the space scales considered here, namely, on the order of a few thousand kilometers. However, regions in which 226Ra and Ba displayed nonconservative behavior and in some cases decoupled behaviors were also identified, mostly at the ocean boundaries (seafloor, continental margins and surface waters). Elevated 226Ra and Ba concentrations found in deepwater in the West European Basin suggest that lower Northeast Atlantic Deep Water (NEADWl) accumulates 226Ra and Ba from sediment diffusion and/or particle dissolution during transport. In the upper 1500 m of the West European Basin, deficiencies in 226Ra and Ba are likely explained by their incorporation in planktonic calcareous

Radiochemical determination and separation or total radium, 226Ra and 224Ra; Analisis Radioquimico de Radio total, Radio-226 y Radio-224

Energy Technology Data Exchange (ETDEWEB)

Suarez, J A; Gonzalez, J A; Pablo, M A. de

1987-07-01

Radiochemical purification and separation of radium has been carried out and the determination of total radium solubilized in aqueous samples has been studied assuming that all the alpha emitters of the sample have their origin in the 226Ra and elements of its desintegration chain. Also, the activities of 22Ra and 226 Ra have been evaluated separately doing a measurement after the chemical separation of the radium and another one 10 days after. (Author) 9 refs.

Determination of 226Ra and 228Ra in surface seawater around Sagami bay and its vicinity

International Nuclear Information System (INIS)

Nakano-Ohta, T.; Kubota, T.; Mahara, Y.; Yoshikawa, M.; Sato, J.

2006-01-01

Activity ratios of 228 Ra/ 226 Ra in surface seawaters were observed at 5 ports of Izu-Oshima, Ajiro port of Sagami bay and Umizuri park of Tokyo bay. The 228 Ra/ 226 Ra activity ratio in surface seawaters were from 0.2 to 0.7 for Izu-Oshima, from 0.2 to 0.7 for Ajiro port and from 0.6 to 0.8 for Tokyo bay. The activity ratio in surface seawaters of Izu-Oshima and Atami of Sagami bay showed lower in spring and highly in autumn, while narrow variation pattern was observed in Umizuri park of Tokyo bay. The observed variation patterns of 228 Ra/ 226 Ra in surface seawaters at Izu-oshima, Ajiro park and Umizuri park may be reflected by difference of contribution from amount of seawater far off coast with low 228 Ra concentration. (author)

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

International Nuclear Information System (INIS)

Dowdall, M.; O'Dea, J.

2002-01-01

This paper presents the results of a study into the anomalous 226 Ra/ 238 U disequilibrium ( 226 Ra/ 238 U of 0.5-9) exhibited by an upland organic soil in Co. Donegal, Ireland. Radiochemical speciation of 226 Ra, 238 U and 228 Ra indicates that in this organic soil the high 226 Ra/ 238 U ratio is due to loss of 238 U relative to 226 Ra via oxidation and mobilisation of 238 U in the upper layers of the soil and subsequent loss in solution. At the lower, more reducing depths of the soil profile, 238 U and 226 Ra are essentially in equilibrium. Loss of 238 U appears to occur primarily from the easily oxidised organic and iron oxide fractions of the soil, samples exhibiting high 226 Ra/ 238 U ratios displaying significantly lower 238 U levels in these fractions than samples whose ratio is below the average value for the soil of the valley. Selective enrichment of 226 Ra by plants or preferential leaching of 226 Ra from the underlying rock is not supported by the results of this study

210Pb and 226Ra distributions in the circumpolar waters

International Nuclear Information System (INIS)

Chung, Y.

1981-01-01

210 Pb and 226 Ra profiles have been measured at five GEOSECS stations in the Circumpolar region. These profiles show that 226 Ra is quite uniformly distributed throughout the Circumpolar region, with slightly lower activities in surface waters, while 210 Pb varies with depth as well as location or area. There is a subsurface 210 Pb maximum which matches the oxygen minimum in depth and roughly correlates with the temperature and salinity maxima. This 210 Pb maximum has its highest concentrations in the Atlantic sector and appears to originate near the South Sandwich Islands northeast of the Weddell Sea. Concentrations in this maximum decrease toward the Indian Ocean sector and then become fairly constant along the easterly Circumpolar Current. Relative to 226 Ra, the activity of 210 Pb is deficient in the entire water column of the Circumpolar waters. The deficiency increases from the depth of the 210 Pb maximum toward the bottom, and the 210 Pb/ 226 Ra activity ratio is lowest in the Antarctic Bottom Water, indicating a rapid removal of Pb by particulate scavenging in the bottom layer and/or a short mean residence time of the Antarctic Bottom Water in the Circumpolar region. 226 Ra is essentially linearly correlated with silica and barium in the Circumpolar waters. However, close examination of the vertical profiles reveals that Ba and Si are more variable than 226 Ra in this region. (orig.)

Assessment of 226Ra age-dependent dose from water intake

International Nuclear Information System (INIS)

Porntepkasemsan, Boonsom; Srisuksawad, Kanitha

2008-01-01

The radioactivity in canal and ground waters collected in a 2-year long observation from the vicinity of the Rare Earth Research and Development Center (RRDC), Phathumthani Province, Thailand, was measured in order to determine the concentration of 226 Ra and to estimate the age-dependent effective dose to humans due to consumption. 226 Ra activities in both canal and ground waters were well below the WHO guidance level for drinking water quality of 1 Bq L -1 . The highest 226 Ra effective doses per year were found for infants and teens. However, the observed levels of calculated 226 Ra effective doses for all age groups in both canal and ground waters show satisfactory low values (less than 15 μSv yr -1 ). These values are acceptable in accordance with the WHO recommended reference dose level of 100 μSv yr -1 from water intake of 2 L day -1

226Ra determination in phosphogypsum by alpha-particle spectrometry

International Nuclear Information System (INIS)

Aguado, J.L.; Bolivar, J.P.; Garcia-Tenorio, R.

1999-01-01

A radiochemical method for 226 Ra determination by alpha-particle spectrometry in environmental samples has been developed in our laboratory. The method has been validated by measurements in samples with known concentrations of this radionuclide and it has been applied in studies related to 226 Ra behaviour in phosphogypsum (the main by-product of producing phosphoric acid from phosphate rocks). (author)

Research on background neutron of 226Ra γ source

International Nuclear Information System (INIS)

Ji Changsong

1996-01-01

This work studies the background neutron emission of 226 Ra γ source: the mechanism of resulting in background neutron is studied; a thesis that the (α, n) type reaction on Radium carriers Cl or Br is the main source of creating background neutron emission of 226 Ra γ source has been proposed and certificated; a proposal of substitution of Cl carrier by Br in radium source produced in China in order to reduce background neutron emission is put forward. A result to reduce the background neutron from 96.4 neutrons/4πsmgRa to 6.1 neutrons/4πsmgRa is obtained

226Ra and 228Ra activities associated with agricultural drainage ponds and wetland ponds in the Kankakee Watershed, Illinois-Indiana, USA

International Nuclear Information System (INIS)

Sidle, W.C.; Shanklin, D.; Lee, P.Y.; Roose, D.L.

2001-01-01

Background radioactivity is elevated in many agricultural drainage ponds and also constructed wetland ponds in the Kankakee watershed. During 1995-1999, gross-α and -β activities were measured up to 455 and 1650 mBq L -1 , respectively. 226 Ra and 228 Ra averaged 139 and 192 mBq L -1 in controlled drainage ponds compared to 53 and 58 mBq L -1 for 226 Ra and 228 Ra, respectively, in native wetland ponds. Analyses of applied ammonium phosphate fertilizers near both native and controlled ponds indicate comparable 226 Ra/ 228 Ra and 228 Ra/ 232 Th activity ratios with only the surface waters in the controlled ponds. For example, 226 Ra/ 228 Ra activity ratios in controlled ponds ranged from 0.79 to 0.91 and group with a local fertilizer batch containing FL phosphate compounds with 226 Ra/ 228 Ra activity ratios of 0.83-1.04. Local soils of the Kankakee watershed have 226 Ra/ 228 Ra activity ratios of 0.54-0.70. Calculated Ra fluxes of waters, in drainage ditches associated with these controlled ponds, for 226 Ra ranged from 0.77 to 9.00 mBq cm -2 d -1 and for 228 Ra ranged from 1.22 to 8.43 mBq cm -2 d -1 . Ra activity gradients were measured beneath these controlled ponds both in agricultural landscapes and in constructed wetlands, all being associated with drainage ditches. Ra had infiltrated to the local water table but was below regulatory maximum contaminant limits. Still, measurable Ra activity was measured downgradient of even the constructed wetlands in the Kankakee watershed, suggesting that the attenuation of Ra was low. However, no Ra excess was observed in the riparian zone or the Kankakee River downgradient of the native wetland ponds

226Ra behavior in the Pee Dee river-Winyah Bay estuary

International Nuclear Information System (INIS)

Elsinger, R.J.; Moore, W.S.

1980-01-01

Concentrations of dissolved 226 Ra in Winyah Bay, South Carolina, and in the adjacent Atlantic Ocean are augmented by the desorption of radium from sediments in the low-salinity area of the estuary and diffusion from bottom sediments. Desorption of 226 Ra is reflected by lower concentrations in suspended sediments from higher-salinity regions of the estuary. Bottom sediments from the high-salinity region have lower 226 Ra/ 230 Th activity ratios than those from the low-salinity end. (orig./ME)

Determination of Ra-226 by gamma-ray spectrometry

International Nuclear Information System (INIS)

Martinez Lobo, A.

1988-01-01

This work deals with the method of determination of 226 Ra by low energy photon spectrometry. For this purpose, the interference due to 235 U, that emits a photon with a close energy, has to be considered. The contribution of 235 U to the 186 KeV photopeak is studied through the 63 KeV 234 Th and the 144 KeV 235 U emissions. From the minimum detectable activity of 226 Ra it is discussed the applicability of this method to several kind of samples. (Author)

Preparation of 227Ac by neutron irradiation of 226Ra

International Nuclear Information System (INIS)

Kukleva, E.; Kozempel, J.; Vlk, M.; Micolova, P.; Vopalka, D.

2015-01-01

Radium-223 is prospective alpha-emitting therapeutic radionuclide for targeted radionuclide therapy. Although 223 Ra is formed naturally by the decay of 235 U, for practical reasons its preparation involves neutron irradiation of 226 Ra. The α-decay of the 227 Ra (T 12 = 43 min.) produced via 226 Ra(n,γ) 227 Ra reaction leads to 227 Ac, a mother nuclide of 227 Th and 223 Ra subsequently. Irradiation target radium material is generally available in multi-gram quantities from historical stock. Main aim of this study was to experimentally and theoretically evaluate and verify available literature data on production of 223 Ra. According to data obtained from γ-spectra, the approximate yield values were determined and effective cross-section for the 223 Ra production was calculated. (authors)

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

International Nuclear Information System (INIS)

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

2016-01-01

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 11 days. - Highlights: • Radium isotope concentrations were evaluated along a large estuarine system. • The radioactivity level in river, estuary and sediments was within a normal range. • Spatial distributions of site specific radionuclides have differing activities and sources.

Ra-226 concentrations in blueberries Vaccinium angustifolium Ait. near an inactive uranium tailings site in Elliot Lake, Ontario, Canada

International Nuclear Information System (INIS)

Dave, N.K.; Lim, T.P.; Cloutier, N.R.

1985-01-01

Ra-226 concentrations were measured in blueberries growing around the Stanrock uranium tailings area near Elliot Lake, Ontario, Canada. Elevated levels of total Ra-226 ranging between 20 to 290 mBq g -1 were observed in samples collected within 500 m from the tailings. Highest levels, approx. 285 mBq g -1 , were observed in a sample collected on a tailings spill. For sites located more than 500 m away in the upwind direction, and those situated at distances greater than 1 km downwind from the waste pile, the total Ra-226 concentrations approached background levels which were measured as 2 to 6 mBq g -1 . Approximately 17% of the total Ra-226 measured was removable by washing the samples with distilled water. Wind dispersal of the tailings material and its deposition in the form of dust on blueberries was believed to be responsible for the external contamination. Based on the ICRP recommended dose limits for oral intake of Ra-226, it was calculated that approximately 160 kg a -1 , 3350 kg a -1 and 47 kg a -1 of washed blueberries from inside and outside the influenced zone, and from the tailings spill site, respectively, would need to be consumed before the individual annual limit for the general public was exceeded. (author)

Measuring the radium quartet ({sup 228}Ra, {sup 226}Ra, {sup 224}Ra, {sup 223}Ra) in seawater samples using gamma spectrometry

Energy Technology Data Exchange (ETDEWEB)

Beek, P. van, E-mail: vanbeek@legos.obs-mip.f [LEGOS, Laboratoire d' Etudes en Geophysique et Oceanographie Spatiales (CNRS/CNES/IRD/UPS), Observatoire Midi Pyrenees, 14 Avenue Edouard Belin, 31400 Toulouse (France); Souhaut, M. [LEGOS, Laboratoire d' Etudes en Geophysique et Oceanographie Spatiales (CNRS/CNES/IRD/UPS), Observatoire Midi Pyrenees, 14 Avenue Edouard Belin, 31400 Toulouse (France); Reyss, J.-L. [LSCE, Laboratoire des Sciences du Climat et de l' Environnement (CNRS/CEA/UVSQ), Avenue de la Terrasse, 91198 Gif-sur-Yvette (France)

2010-07-15

Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While {sup 228}Ra and {sup 226}Ra are usually measured using gamma spectrometry, short-lived Ra isotopes ({sup 224}Ra and {sup 223}Ra) 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 {sup 226}Ra, {sup 228}Ra, {sup 224}Ra, {sup 223}Ra activities measured using low-background gamma spectrometry in standard samples, in water samples collected in the vicinity of our laboratory (La Palme and Vaccares lagoons, France) but also in seawater samples collected in the plume of the Amazon river, off French Guyana (AMANDES project). The {sup 223}Ra and {sup 224}Ra 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 {sup 224}Ra activities are similar for the two techniques. RaDeCC is more sensitive for the detection of low {sup 223}Ra activities. Gamma spectrometry thus constitutes an alternate method for the determination of short-lived Ra isotopes.

/sup 226/Ra in phosphate nodules from the Peru/Chile seafloor

Energy Technology Data Exchange (ETDEWEB)

Kim, K H; Burnett, W C [Florida State Univ., Tallahassee (USA). Dept. of Oceanography

1985-04-01

/sup 226/Ra and other uranium-series radionuclides have been measured in a suite of marine phosphorite samples from the upwelling area off Peru/Chile by gamma-ray spectrometry and radiochemical techniques. Our results lead to the following conclusions: (1) phosphorite nodules typically show unidirectional growth at rates of 1 to 10 mm/Kyr; (2) very young samples (less than a few thousand years) contain slight excess amounts of /sup 226/Ra probably derived from pore fluids; and (3) slow but persistent leakage of /sup 226/Ra out of phosphate nodules occurs resulting in systematically lower /sup 226/Ra ages compared to /sup 230/Th ages for samples older than about twenty thousand years. Radium fluxes from these phosphate nodules appear to be 1 to 3 orders of magnitude less than those calculated for deep-sea sediments and ferromanganese nodules.

Leaching of 60Co, 137Cs and 226Ra in lysimeter experiments

International Nuclear Information System (INIS)

Gerzabek, M.H.; Mueck, K.; Steger, F.; Algader, S.M.

1996-10-01

The present report describes the first results obtained from lysimeter experiments started in 1990. The lysimeter plant consists of twelve soil monoliths from four different sites (three replicates each). Since 1990 the following agricultural crops were grown: endive, corn, winter wheat, mustard, sugar beet and potato. Gravitational water ranged from 3.9 % to 18.3 % of precipitation plus irrigation water, calculated as half years average values excluding the first six months of operation. The two Cambisols on sediments exhibited a mean percentage of approx. 10 %. The Dystric Cambisol on silicate rock and the Gleysol showed average values of 20 %. In 1990 the top layers (20 cm) were contaminated with three radionuclides. The leaching of the contaminants 60 Co, 137 Cs and 226 Ra differed distinctly between the elements. The lowest leaching rates were observed for 137 Cs, followed by 60 Co. The 226 Ra-concentrations in the gravitational water were clearly highest of all. However, the comparison of the 226 Ra/ 22 2 8 Ra ratios in deep soil layers and in gravitational water showed that the 226 Ra measured in the leachate originates from the natural contents in the subsoil and not from the artificial 226 Ra contamination of the topsoil. The mobility of the artificial radionuclides decreased therefore in the following order: 60 Co > ( 226 Ra) > 137 Cs. (author)

Removal of 226Ra from tailings pond effluents and stabilization of uranium mine tailings. Bench and pilot scale studies

International Nuclear Information System (INIS)

Schmidtke, N.W.; Averill, D.; Bryant, D.N.; Wilkinson, P.; Schmidt, J.W.

1978-01-01

Increased world demand for uranium has resulted in recent expansion of Canadian uranium mining operations. Problems have been identified with the discharge of radionuclides such as 226 Ra from tailings pond effluents and with the stabilization of mine tailings. At Environment Canada's Wastewater Technology Centre (WTC) two projects were undertaken in cooperation with the Canadian Uranium Mining Industry and other federal government agencies to address these problems. The first project reports on the progress of bench and pilot scale process simulations for the development of a data base for the design of a full scale mechanical physical/chemical 226 Ra removal waste treatment system with an effluent target level of 10 pCi 226 Ra total per litre. The second project addresses problems of the leachability of radionuclides and the stabilization of both uranium mine tailings and BaRaSO 4 sediments from the treatment of acid seepages

A theoretical model for the production of Ac-225 for cancer therapy by photon-induced transmutation of Ra-226.

Science.gov (United States)

Melville, G; Fan Liu, Sau; Allen, B J

2006-09-01

Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. We are investigating the reduction of radium by transmutation on a small scale by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) to produce Ra-225, which subsequently decays to Ac-225, which can be used as a generator to produce Bi-213 for use in 'targeted alpha therapy' for cancer. This paper examines the possibility of producing Ac-225 with a linac using an accurate theoretical model in which the bremsstrahlung photon spectrum at 18 MV linac electron energy is convoluted with the corresponding photonuclear cross sections of Ra-226. The total integrated yield can then be obtained and is compared with a computer simulation. This study shows that at 18 MV, the photonuclear reaction on Ra-226 can produce low activities of Ac-225 with a linac. However, a high power linac with high current, pulse length and frequency is needed to produce practical amounts of Ac-225 and a useful reduction of Ra-226.

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

International Nuclear Information System (INIS)

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

2006-01-01

In this study, low-background γ-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

Activity concentration and population dose from 226Ra due to consumption of dietary components

International Nuclear Information System (INIS)

Wagh, S.S.; Patra, A.K.; Ravi, P.M.; Sarkar, P.K.

2012-01-01

226 Ra (T 1/2 = 1620 years, α-energy 4.78 MeV, 4.59 MeV, γ-energy 186 keV), a product of natural uranium decay series, is abundantly observed in natural environment. Radium, along with its homologue calcium, an essential element in the plant system, is absorbed from the soil by plants and gets redistributed. within different parts of the plants. Because of the long half-life of 226 Ra, it gets accumulated in the human body for along time. The hazard due to ingestion of 226 Ra dissolved in water is reported to be about 40 times higher than that of 90 Sr. This paper deals with the concentration of 226 Ra in different dietary components and ingestion dose from 226 Ra due to consumption of dietary components. Internal radiation exposure to non-human biota due to 226 Ra is also discussed

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

International Nuclear Information System (INIS)

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 γ-ray spectrometry. There was a wide range of activities of 228 Ra (0.5-2 Bq/kg-fresh) and 226 Ra (0.5-1.2 Bq/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 = ∼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

Estimation of annual effective dose from 226Ra and 228Ra due to consumption of foodstuffs by inhabitants of Ramsar city, Iran

International Nuclear Information System (INIS)

Asefi, M.; Fathivand, A. A.; Amidi, J.

2005-01-01

226 Ra and 228 Ra contents in foodstuffs of Ramsar which is a coastal city in the northern part of lran were determined by gamma spectrometry. Measurement results together with food consumption rates were used to estimate annual effective dose from 226 Ra and 228 Ra, due to consumption of food stuffs by inhabitants of Ramsar city. Materials and methods: a total of 33 samples from 11 different foodstuffs including root vegetables (beetroot), leafy vegetables (lettuce, parsley and spinach) and tea, meat, chicken, pea, broad bean, rice, and cheese were purchased from markets of Ramsar city and were analyzed for their 226 Ra and 228 Ra concentration. 1-8 kg of fresh weight sample was placed in Marinnelli beaker and sealed. The measurement of natural radioactivity levels as performed by gamma-spectrometry system, using a high purity germanium detector with 40% relative efficiency. Results: The highest concentrations of 226 Ra and 228 Ra were determined in tea samples with 1570 and 1140 mBq/kg, respectively, and the lowest concentration of 226 Ra was in pea, cheese, chicken, broad bean, and beetroot. Conclusion:The maximum estimated annual effective dose from 226 Ra and 228 Ra due to consumption, foodstuffs were determined to be 19.22 and 0.71 mSv from rice and meat samples respectively, where as, minimum estimated annual effective dose for 226 Ra was 0.017, 0.018 and 0.019 mSv from beetroot, cheese and pea samples respectively

226Ra, 228Ra, 223Ra, and 224Ra in coastal waters with application to coastal dynamics and groundwater input

International Nuclear Information System (INIS)

Moore, W.S.

1997-01-01

Four radium isotopes offer promise in unraveling the complex dynamics of coastal ocean circulation and groundwater input. Each isotope is produced by decay of a thorium parent bound to sediment. The activities of these thorium isotopes and the sediment-water distribution coefficient for radium provide an estimate of the source function of each Ra isotope to the water. In salt marshes that receive little surface water input, Ra activities which exceed coastal ocean values must originate within the marsh. In North Inlet, South Carolina, the activities of 226 Ra exported from the marsh far exceed the activities generated within the marsh. To supply the exported activities, substantial groundwater input is required. In the coastal region itself, 226 Ra activities exceed the amount that can be supplied from rivers. Here also, substantial groundwater input is required. Within the coastal ocean, 223 Ra and 224 Ra may be used to determine mixing rates with offshore waters. Shore-perpendicular profiles of 223 Ra and 224 Ra show consistent trends which may be modeled as eddy diffusion coefficients of 350-540 m 2 s -1 . These coefficients allow an assessment of cross-shelf transport and provide further insight on the importance of groundwater to coastal regions. (author)

Determination of ''226Ra by Alpha Spectrometry by Using ''225Ra as Yield Tracer

International Nuclear Information System (INIS)

Crespo, M. T.; Oller, O.

1999-01-01

A method for the determination of low-level ''226 Ra in environmental and geological samples by alpha spectrometry is described. The method is based on the use of ''225 Ra from ''229 Th as yield tracer and has been developed to analyze U, Th and Ra in the same sample. (Author) 12 refs

Rapid determination of 226Ra in drinking water samples using dispersive liquid-liquid microextraction coupled with liquid scintillation counting

International Nuclear Information System (INIS)

Sadi, B.K.; Chunsheng Li; Kramer, G.H.; Johnson, C.L.; Queenie Ko; Lai, E.P.C.

2011-01-01

A new radioanalytical method was developed for rapid determination of 226 Ra in drinking water samples. The method is based on extraction and preconcentration of 226 Ra from a water sample to an organic solvent using a dispersive liquid-liquid microextraction (DLLME) technique followed by radiometric measurement using liquid scintillation counting. In DLLME for 226 Ra, a mixture of an organic extractant (toluene doped with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone) and a disperser solvent (acetonitrile) is rapidly injected into the water sample resulting in the formation of an emulsion. Within the emulsion, 226 Ra reacts with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone and partitions into the fine droplets of toluene. The water/toluene phases were separated by addition of acetonitrile as a de-emulsifier solvent. The toluene phase containing 226 Ra was then measured by liquid scintillation counting. Several parameters were studied to optimize the extraction efficiency of 226 Ra, including water immiscible organic solvent, disperser and de-emulsifier solvent type and their volume, chelating ligands for 226 Ra and their concentrations, inorganic salt additive and its concentration, and equilibrium pH. With the optimized DLLME conditions, the accuracy (expressed as relative bias, B r ) and method repeatability (expressed as relative precision, S B ) were determined by spiking 226 Ra at the maximum acceptable concentration level (0.5 Bq L -1 ) according to the Guidelines for Canadian Drinking Water Quality. Accuracy and repeatability were found to be less than -5% (B r ) and less than 6% (S B ), respectively, for both tap water and bottled natural spring water samples. The minimum detectable activity and sample turnaround time for determination of 226 Ra was 33 mBq L -1 and less than 3 h, respectively. The DLLME technique is selective for extraction of 226 Ra from its decay progenies. (author)

Transfer of 226Ra to plants from two types of soil

International Nuclear Information System (INIS)

Rosiak, L.; Pietrzak-Flis, Z.

1998-01-01

The transfer of 226 Ra to plants used as food (carrot, parsley, wheat) and as fodder (grass, maize) was studied. The plants were grown on two types of soil: sandy soil (l) and sandy loam soil (II) in an open field (exposure to dry and wet deposition, resuspension and soil adhesion) and in polyethylene tent with an underground irrigation system (isolation from wet deposition and from water splash on soil). The plants were grown simultaneously on the open and sheltered fields. The average concentrations of total 226 Ra and of exchangeable 226 Ra were 8.48 ± 0.50 Bq/kg dw was 0.62 ± 0.07 Bq/kg dw , respectively, in Soil I and 12.2 ± 0.56 Bq/kg dw and 0.66 ± 0.05 Bq/kg dw , respectively, in Soil II. 226 Ra was determined in the above-ground parts of the plants after washing in distilled water, in the rinse obtained from washing, in the insoluble residue separated from the rinse, and in the roots. The data obtained allowed us to determine the incorporated radionuclide in the plants and on their surface. Statistical analysis of the data indicates that there is no difference in the incorporated 226 Ra for plants grown on the open field and in the tent. This indicates that Ra enter the plants mainly through the root system, while the pathway via leaves and stems is negligible

Migration of 226 Ra, 228 Ra, 210 Pb, U and Th from phosphogypsum

International Nuclear Information System (INIS)

Silva, Nivaldo Carlos da; Cipriani, Moacir; Taddei, Maria Helena T.

2002-01-01

The physico-chemical availability of radioactive elements ( 210 Pb, 226 Ra, 228 Ra, Th and U) in Brazilian phosphogypsum was investigated in a large scale leaching experiment carried out in lysimeters, using phosphogypsum samples (approximately 1.2 tons) from two phosphoric acid industries. Lysimeters were built using cylindrical concrete containers with 0.9 m inner diameter and 2 m depth. The bottom of the lysimeter was filled with a 10 cm layer of gravel covered with geomembrane sheet. Under this layer a pipe was designed to drain the percolated water. Three lysimeters were filled with phosphogypsum from each industry and a mixture of both. As percolated water comes exclusively from the rain, sample was collected daily when available. Samples were then pooled weekly, carefully prepared and submitted to radiochemical analysis. Radiochemical characterization of phosphogypsum and percolated water was performed by radiochemical separation followed by gross alpha and beta counting ( 226 Ra, 228 Ra and 210 Pb) and UV-Vis spectrophotometry with Arsenazo III (U and Th). This experiment was carried out from 12/01/1999 to 01/22/2001, with a precipitation of 2,732 mm. It was observed that approximately 40% (534 L) of the rain fall percolated through the lysimeter 1. The analysis of 22 samples of percolated water from lysimeter 1 showed mean radionuclides activities of 70±30 mBqL -1 , 70±50 mBqL -1 , 100±60 mBqL -1 and 110±55 mBqL -1 for U, 226 Ra, 228 Ra and 210 Pb, respectively. Thorium activities were below detection limit. (author)

Effects of barium chlorine treatment of uranium ore on 222Rn emanation and 226Ra leachability from mill tailings

International Nuclear Information System (INIS)

Ibrahim, S.A.; Church, S.L.; Whicker, F.W.

1985-01-01

The purpose of this laboratory study was to investigate the effectiveness of barium chloride treatment of uranium ore on 222 Rn emanation from mill tailings, 226 Ra level in waste-water, and the leachability of radium from tailings. It has been shown that barium sulfate is an excellent carrier for radium and that barium sulfate crystals have high retention capacity for radon gas produced by radium trapped within the lattice. Ground uranium ore from a mine in Wyoming was mixed with water to form a 1:1 ratio before barium and potassium chlorides were added at concentrations of 0, 10, 25, 50, and 100 mg per liter of slurry. The ore was then subjected to a simulated mill process using sulfuric acid leaching. The liquid representing tailings pond water was separated and analyzed for 226 Ra and the solid fraction, representing mill tailings, was tested for radon emanation and the leachability of radium by deionized water. This study suggests that barium treatment of uranium ore prior to sulfuric acid leaching could be effective in reducing radon emanation from tailings and also in reducing the 226 Ra concentration of waste-water. Leachability of radium from treated tailings was markedly reduced

226Ra, 210Pb and calcium in eyes of long-term radium cases

International Nuclear Information System (INIS)

Holtzman, R.B.; Sha, J.Y.; Plondke, N.J.

1978-01-01

It is known that dogs injected with radium accumulate a significant fraction of this element in the eye, with consequent radiation damage. We are interested in looking for similar concentrations in the human eye. An eye from each of two radium cases (01-144 and 01-017) with body burdens of 690 and 1210 nCi 226 Ra, respectively, was analyzed for 226 Ra, 210 Pb and calcium. The total amounts in the eyes were 1.80 pCi 226 Ra, 1.3 pCi 210 Pb and 2.3 mg of calcium in Case 01-144 and 5.4 pCi 226 Ra, 3.6 pCi 210 Pb and 14.2 mg of calcium in Case 01-017. For the latter case the eye was dissected and showed the highest 226 Ra concentrations (on a wet weight basis) in the choroid (3.8 pCi/g), sclera (3.4 pCi/g) and iris (2.9 pCi/g). The radium content was 2.7 x 10 -4 % to 4.7 x 10 -4 % of the total body content at 50 to 55 years after first exposure. The 226 Ra/Ca ratios in the whole eye were 1/3 to 1/4 those in the whole body, but that for the choroid from the dissected eye was identical to that of the whole body. For 210 Pb the concentrations in the various parts of the eye were similar to and correlated with those of the 226 Ra. The 210 Pb/Ca ratios in the eye are comparable to those of the whole body, which indicates that the eye concentrates 210 Pb relative to 226 Ra. These data will be compared to those from the dog and the differences will be discussed. (author)

Activity concentrations of 238U and 226Ra in scales formed on pipes of industrial boilers in the state of Pernambuco, Brazil

International Nuclear Information System (INIS)

Poggi, Claudia M.B.; Farias, Emerson E.G. de; Gazineu, Maria H.P.

2015-01-01

The procedures employed in the industry can generate significant amounts of solid, liquid and gaseous wastes that usually contain toxic or materials of difficulty degradation. One of the facts that contribute to the formation of such wastes is the generation of steam used in operating processes and industry segments. Currently, steam supplied by boilers is the most economical and practical mode of heat transfer in industrial processes. Due to the high temperature of water used in these processes, compounds which were previously soluble become insoluble, generating residues called scales. This material, which contains stable ions, can also present naturally occurring radionuclides such as 238 U and 226 Ra, which concentrate over time in piping and equipment surfaces. If not disposed correctly, this material also can contaminate the environment. The main origin of these radionuclides is the use of groundwater in industrial processes. Thus, in regions of naturally enriched in radionuclides such as the Region of Pernambuco, including the municipalities of Paulista and Goiana, there is a greater possibility of radioactive scale formation. Therefore, this study aimed to determine the activity concentrations of 238 U and 226 Ra present in the solid wastes generated by industries situated in Paulista and Goiana, in order to assess radionuclide disequilibrium. For the sake of comparison, scale samples collected from industries located in the municipality of Caruaru, far from the previous municipalities, were also analyzed. The determination of the activity concentrations for 238 U and 226 Ra was performed by High Resolution Gamma-Ray Spectrometry. Samples were collected, prepared, packed in plastic containers and set aside for a minimum time of 21 days, for the secular equilibrium to occur between 226 Ra and its short lived descendants. The counting time was 80,000 seconds. Gamma energies used for determination of activity concentrations were 1001 keV for 238 U, and 352 ke

Contamination of terrestrial ecosystem components with 90Sr, 137Cs, and 226Ra caused by the deterioration of the multibarrier protection of radioactive waste storages

Science.gov (United States)

Latynova, N. E.

2010-03-01

The spatial-temporal features of the radioactive contamination of terrestrial ecosystem components caused by the deterioration of the multibarrier protection of regional radioactive waste storages of the State Research Center of the Russian Federation-Leipunskii Institute of Physics and Power Engineering at the input of radionuclides into the soil and ground water were studied. The composition of the radioactive contamination was determined, and the hydrological and geochemical processes resulting in the formation of large radioactive sources were described. The natural features of the radioactive waste storage areas favoring the entry of 90Sr, 137Cs, and 226Ra into the soils and their inclusion in the biological turnover were characterized. The directions of the horizontal migration of 90Sr, 137Cs, and 226Ra and the sites of their accumulation within the superaquatic and aquatic landscapes of a near-terrace depression were studied; the factors of the 90Sr accumulation in plants and cockles were calculated. The results of the studies expand the theoretical concepts of the mechanisms, processes, and factors controlling the behavior of radionuclides at the deterioration of the multibarrier protection of radioactive waste storages. The presented experimental data can be used for solving practical problems related to environmental protection in the areas of industrial nuclear complexes.

Possibility of rapidly reporting 226Ra activity in 226Ra-222Rn samples with unknown equilibrium factor by γ spectrometer

Institute of Scientific and Technical Information of China (English)

SU Qiong; ZHENG Rui; CHEN Yong; CHENG Jian-Ping

2004-01-01

This paper reports the observed changes for equilibrium factors between 226Ra and 222Rn with sealing time of the samples. The samples include soil, raw coal, mineral water, cement, rock, etc. Especially the conceptions of "pre-equilibrium time" and "pre-equilibrium factor" have been put forward and methods of measuring and processing data have been given which can be used for rapidly reporting activity of 226Ra in samples with unknown equilibrium factor. It is definitely concluded that, using methods given in the paper, a test report will be completed in 3～7days, instead of one month, after receiving the sample whose activity is not lower than LLD of the spectrometer.

Validation of 226Ra, 228Ra and 210Pb measurements in soil and sediment samples through high resolution gamma ray spectrometry

International Nuclear Information System (INIS)

Dias, Danila Carrijo da Silva; Silva, Nivaldo Carlos da; Bonifacio, Rodrigo Leandro; Guerrero, Eder Tadeu Zenun

2013-01-01

Radionuclides found in ore extraction waste materials are a great source of concern regarding public health and environmental safety. One technique to determine the concentration of substances is high resolution gamma ray spectrometry using HPGe. Validating a measurement technique is essential to warrant high levels of quality to any scientific work. The Laboratory of Pocos de Caldas of the Brazilian Commission for Nuclear Energy partakes into a Quality Management System project, seeking Accreditation under ISO/IEC 17025 through the validation of techniques of chemical and radiometric analysis of environmental samples from water, soil and sediment. The focus of the Radon Laboratory at LAPOC is validation of Ra-226, Ra-228 and Pb-210 concentration determinations in soil and sediment through a gamma spectrometer system. The stages of this validation process included sample reception and preparation, detector calibration and sample analyses. Dried samples were sealed in metallic containers and analyzed after radioactive equilibrium between Ra-226 and daughters Pb-214 and Bi-214. Gamma spectrometry was performed using CANBERRA HPGe detector and gamma spectrum software Genie 2000. The photo peaks used for Ra-226 determination were 609 keV and 1020 keV of Bi-214 and 351 keV of Pb-214. For the Ra-228 determination a photopeak of 911 keV was used from its short half-life daughter Ac-228 (T1/2 = 6.12 h). For Pb-210, the photopeak of 46.5 keV was used, which, due to the low energy, self-absorption correction was needed. Parameters such as precision, bias/accuracy, linearity, detection limit and uncertainty were evaluated for that purpose. The results have pointed to satisfying results. (author)

Desorption of Ba and 226Ra from river-borne sediments in the Hudson estuary

International Nuclear Information System (INIS)

Li, Y.-H.

1979-01-01

The pronounced desorption of Ba and 226 Ra from river-borne sediments in the Hudson estuary can be explained quantitatively by the drastic decrease in the distribution coefficients of both elements from a fresh to a salty water medium. The desorption in estuaries can augment, at least, the total global river fluxes of dissolved Ba and 226 Ra by one and nine times, respectively. The desorption flux of 226 Ra from estuaries accounts for 17-43% of the total 226 Ra flux from coastal sediments. Two mass balance models depicting mixing and adsorption-desorption processes in estuaries are discussed. (Auth.)

Past and present of risk assessment for RA-226 releases

International Nuclear Information System (INIS)

Paschoa, A.S.

1982-12-01

Some of the new concepts introduced by ICRP 26 seem to be difficult to apply to the case of dose limits concerning the 226 Ra releases from the front end of the nuclear fuel cycle. Accordingly most national legislations have not been permeated yet by the 226 Ra dose limits based on such concepts. This work calls the attention on the one hand that a loose concept of acceptable risk is implicitly used in a dose limitation system for 226 Ra when such system is based on calculating the dose as a fraction of the (MPC) sub(w) introduced earlier by the ICRP 2, and on the other hand that the ALI currently recommended by the ICRP 30 should be used only in the framework of the recommendations published in the ICRP 26, which adopts a better defined concept of risk. (Author) [pt

Determination of long-lived natural Ra isotopes, 226Ra, in mineral and spring waters from Caxambu (MG) and Aguas de Lindoia (SP) spas

International Nuclear Information System (INIS)

Negrao, Sergio Garcia

2012-01-01

The aim of this work was to study the long-lived Ra isotopes, 226 Ra and 228 Ra, natural distribution in mineral and spring waters from Caxambu (MG) and Aguas de Lindoia (SP) water parks. In Caxambu mineral waters it was observed 228 Ra activity concentrations slightly higher than those of 226 Ra. The elevated content of carbonates and bicarbonates of these waters can result in an increased solubility of the both Ra isotopes and may play an important role for the fate of 228 Ra and its equilibrium distribution between solid and liquid phases. In Caxambu Thermal Spa, arithmetic mean activities ranged from 83 mBq L -1 to 3599 mBq L -1 and from 60 mBq L -1 to 4481 mBq L -1 for 226 Ra and 228 Ra, respectively. The highest 226 Ra activity was found in Venancio Spring, while the maximum 228 Ra activity value was determined in Ernestina Guedes. 228 Ra/ 226 Ra activity ratios varied from 0.079 (Conde D'Eau and Princesa Isabel Spring) to 4.2 (Mairink II Spring). In Aguas de Lindoia, arithmetic mean activities ranged from 4.6 mBq L -1 to 41 mBq L -1 and from 30 mBq L -1 to 54 mBq L -1 for 226 Ra and 228 Ra, respectively. The maximum 226 Ra activity concentration was found in the bottled mineral water Sao Jorge, while the higher 228 Ra activity concentration was determined in Santa Filomena Spring (public station 2). 228 Ra/ 226 Ra activity ratios varied from 1.2 (bottled mineral water Sao Jorge) to 9.1 (bottled mineral water Jatoba 1). This work also performed the dose assessment due to the ingestion of 226 Ra and 228 Ra in Caxambu and Aguas de Lindoia mineral and spring waters. The committed effective doses were estimated by using a conservative dosimetric model and taking into account the results over a lifetime (70 years) following intake of both long-lived Ra isotopes. The results from this radiological evaluation showed that the guidance committed effective dose level of 0.1 mSv y-1 recommended by World Health Organization was exceeded in almost all samples studied in

Content and spatial distribution of 226Ra in the soils of industrial objects and seliteb zone of the Kara-Balta Complex

International Nuclear Information System (INIS)

Vasil'ev, I.A.; Alekhina, V.M.; Tolongutov, B.M.; Mamatbraimov, S.

2001-01-01

In the presentation the laboratory studies results of the Kara-Balta Complex area soils by the γ-spectrometry method for quantitative analysis of γi-radiating isotopes content ( 226 Ra and products of its decay, as well as another isotopes, for instant, of the thorium series) are presented. For analysis of soils γ-spectra the scintillation γ-spectrometer with NaI(Tl) crystal in the capacity of detector was used. It was determined, that the main reasons for 226 Ra anomalous concentration appealing are the Hydrometallurgical Plant' wastes losses during hydro-transporting at the pipeline accidents periods, also the ore losses at their reloading, a cars decontamination and radionuclides washing from wasted technological constructions outside the working rooms

226Ra, 228Ra and 40K in scales formed in boilers of industrial installations

International Nuclear Information System (INIS)

Poggi, Claudia M. Braga; Farias, Emerson Emiliano G. de; Hazin, Clovis A.; Gazineu, Maria Helena P.; Universidade Catolica de Pernambuco

2011-01-01

Many industrial processes involve the production of steam in boilers, which is sent through pipes to machines and other equipment used in different sectors of the installations. The water commonly used in these processes is groundwater, which generally has high concentrations of calcium and magnesium salts, that can co-precipitate with naturally occurring radioactive elements such as 226 Ra and 228 Ra creating radioactive scales, which are deposited in pipes, thus decreasing the efficiency of steam production. In addition, 40 K that is present in all soils and rocks with a concentration of about 0.012% of natural potassium can also be concentrated in these scales. No data was found in literature relating to radionuclides present in the scales formed on boilers in general. In this context, the purpose of this work was to determine concentrations of 226 Ra, 228 Ra and 40 K, in scales generated inside boilers from different industries in the cities of Caruaru, Paulista and Goiana, Pernambuco. Determination of the radionuclides concentration was performed by gamma spectrometry with an HPGe detector, calculating their specific activities. Activity concentrations of 226 Ra were in the range of -1 and 228 Ra activity concentrations varied from 1 . Activity concentrations of 40 K were in the range of -1 . All these activity concentrations were lower than the limits established by the Brazilian Nuclear Energy Commission of for this type of matrix. (author)

Recalibration of the 226Ra emanation analysis system

International Nuclear Information System (INIS)

Lucas, H.F. Jr.; Markun, F.

1982-01-01

The 226 Ra emanation system was found to require recalibration. The gain of the various counting systems was established to about +-0.5%. The variance introduced into the analysis by multiple counting systems was low and corresponded to a fractional standard deviation of +-0.5%. The variance introduced into the analysis by both multiple counting systems and multiple counting chambers needs to be redetermined but is less than a fractional standard deviation of +-2%. The newly established calibration factor of 5.66 cpm/pg 226 Ra is about 6% greater than that used previously. The leakage of radon into the greased fittings of the emanation flask which was indicated in an earlier study was not confirmed

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

International Nuclear Information System (INIS)

Manjon, G.; Vioque, I.; Moreno, H.; Garcia-Tenorio, R.; Garcia-Leon, M.

1997-01-01

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

The effects of chronic, low doses of Ra-226 on cultured fish and human cells

Energy Technology Data Exchange (ETDEWEB)

Shi, Xiaopei; Seymour, Colin; Mothersill, Carmel, E-mail: mothers@mcmaster.ca

2016-07-15

Purpose: To determine the chronic low-dose radiation effects caused by α-particle radiation from {sup 226}Ra over multiple cell generations in CHSE/F fish cells and HaCaT human cells. Methods: CHSE/F cells and HaCaT cells were cultured in medium containing {sup 226}Ra to deliver the chronic low-dose α-particle radiation. Clonogenic assay was used to test the clonogenic survival fractions of cells with or without being exposed to radiation from {sup 226}Ra. Results: The chronic low-dose radiation from {sup 226}Ra does have effects on the clonogenic survival of CHSE/F cells and HaCaT cells. When CHSE/F cells were cultured in {sup 226}Ra-medium over 9 passages for about 134 days, the clonogenic surviving fractions for cells irradiated at dose rates ranging from 0.00066 to 0.66 mGy/d were significantly lower than that of cells sham irradiated. For HaCaT cells grown in medium containing the same range of {sup 226}Ra activity, the clonogenic surviving fraction decreased at first and reached the lowest value at about 42 days (8 passages). After that, the clonogenic survival began to increase, and was significantly higher than that of control cells by the end of the experimental period. Conclusion: The chronic, low-dose high LET radiation from {sup 226}Ra can influence the clonogenic survival of irradiated cells. CHSE/F cells were sensitized by the radiation, and HaCaT cells were initially sensitized but later appeared to be adapted. The results could have implications for determining risk from chronic versus acute exposures to radium. - Highlights: • Cells were exposed to chronic low-dose α-radiation from {sup 226}Ra in medium with {sup 226}Ra. • The clonogenic survival of CHSE/F cells decreased when exposed to {sup 226}Ra for 134 days. • The clonogenic survival of HaCaT cells decreased at first and then increased. • The doubling time of both cells were not affected by this kind of radiation.

Values of soil-plant transfer factor of 226Ra and 228Ra: agricultural areas versus areas of high natural radioactivity

International Nuclear Information System (INIS)

Wasserman, Maria Angelica; Lauria, Dejanira; Perez, Daniel Vidal; Schuch, Luiz Alexandre; Zago, Ari

2000-01-01

In this work, soil to plant transfer factor of 226 Ra and 228 Ra obtained in areas of traditional agricultural practices varied as a function of the considered cultivated species but little variation was observed as a function of the soil type. Beans and soybeans presented more important absorption than cereals (corn, rice and wheat). In our work legumes (bean and soybean) presented transfer factors up to one order of magnitude higher than average values for regions where natural radioactivity is high. On the other hand, the results for cereals did not presented such clear differences. It can be concluded that cultural inputs of 226 Ra and 228 Ra are occurring in agricultural areas, but few species can concentrate it. The transfer factor values obtained in this work for 226 Ra and 228 Ra can be applied in risk assessment models. (author)

Distribution of Ra-226 in the Ross Sea, Antarctica

International Nuclear Information System (INIS)

Bettoli, M.G.; Cantelli, L.; Queirazza, G.; Roveri, M.; Tositti, L.; Tubertini, O.; Valcher, S.

1996-01-01

An improved procedure for the determination of Rn-222 and Ra-226 in seawater developed for easier on-board operations is presented. Data on the radioactive disequilibrium between the mentioned radionuclides as directly determined in the field can be greatly helpful in the study of the gas-exchange processes at the air-sea interface, especially as far as the Antarctic Ocean is concerned. The method employed has been preliminary tested in laboratory on a set of seawater samples collected in the Ross Sea and Ra-226 data collected are discussed and compared to literature data. (UK)

Values of soil-plant transfer factor of {sup 226}Ra and {sup 228}Ra: agricultural areas versus areas of high natural radioactivity; Valores de fator de transferencia solo-planta do {sup 226}Ra e {sup 228}Ra: areas agricolas versus areas de radioatividade natural elevada

Energy Technology Data Exchange (ETDEWEB)

Wasserman, Maria Angelica; Lauria, Dejanira [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Perez, Daniel Vidal [Empresa Brasileira de Pesquisa Agropecuaria, Rio de Janeiro, RJ (Brazil). Centro Nacional de Pesquisa de Solos; Schuch, Luiz Alexandre [Santa Maria Univ., RS (Brazil). Dept. de Fisica; Zago, Ari [Santa Maria Univ., RS (Brazil). Dept. de Solos

2000-07-01

In this work, soil to plant transfer factor of {sup 226}Ra and {sup 228}Ra obtained in areas of traditional agricultural practices varied as a function of the considered cultivated species but little variation was observed as a function of the soil type. Beans and soybeans presented more important absorption than cereals (corn, rice and wheat). In our work legumes (bean and soybean) presented transfer factors up to one order of magnitude higher than average values for regions where natural radioactivity is high. On the other hand, the results for cereals did not presented such clear differences. It can be concluded that cultural inputs of {sup 226}Ra and {sup 228}Ra are occurring in agricultural areas, but few species can concentrate it. The transfer factor values obtained in this work for {sup 226}Ra and {sup 228}Ra can be applied in risk assessment models. (author)

Using 226Ra/228Ra disequilibrium to determine the residence half-lives of radium in vegetation compartments

International Nuclear Information System (INIS)

Baeza, A.; Barandica, J.; Paniagua, J.M.; Rufo, M.; Sterling, A.

1999-01-01

The concentrations of 226 Ra and 228 Ra were studied in different vegetation compartments and in available and non-available soil fractions in a Mediterranean scrubland ecosystem. A high percentage of the plant samples showed an apparent discrimination in favour of 226 Ra over 228 Ra. A linear compartmental model was applied to the soil-plant system. It allowed us to explain why these discrimination coefficients differed from unity, to obtain the residence half-lives of radium in the different compartments, to estimate the age of the plants, and to simulate the temporal evolution of the radioactive concentrations in each compartment. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Activity concentrations of {sup 238}U and {sup 226}Ra in scales formed on pipes of industrial boilers in the state of Pernambuco, Brazil

Energy Technology Data Exchange (ETDEWEB)

Poggi, Claudia M.B.; Farias, Emerson E.G. de, E-mail: claudiapoggi04@gmail.com, E-mail: emersonemiliano@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Franca, Elvis J.; Hazin, Clovis A., E-mail: chazin@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Gazineu, Maria H.P., E-mail: helena@unicap.br [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil). Centro de Ciencias e Tecnologia

2015-07-01

The procedures employed in the industry can generate significant amounts of solid, liquid and gaseous wastes that usually contain toxic or materials of difficulty degradation. One of the facts that contribute to the formation of such wastes is the generation of steam used in operating processes and industry segments. Currently, steam supplied by boilers is the most economical and practical mode of heat transfer in industrial processes. Due to the high temperature of water used in these processes, compounds which were previously soluble become insoluble, generating residues called scales. This material, which contains stable ions, can also present naturally occurring radionuclides such as {sup 238}U and {sup 226}Ra, which concentrate over time in piping and equipment surfaces. If not disposed correctly, this material also can contaminate the environment. The main origin of these radionuclides is the use of groundwater in industrial processes. Thus, in regions of naturally enriched in radionuclides such as the Region of Pernambuco, including the municipalities of Paulista and Goiana, there is a greater possibility of radioactive scale formation. Therefore, this study aimed to determine the activity concentrations of {sup 238}U and {sup 226}Ra present in the solid wastes generated by industries situated in Paulista and Goiana, in order to assess radionuclide disequilibrium. For the sake of comparison, scale samples collected from industries located in the municipality of Caruaru, far from the previous municipalities, were also analyzed. The determination of the activity concentrations for {sup 238}U and {sup 226}Ra was performed by High Resolution Gamma-Ray Spectrometry. Samples were collected, prepared, packed in plastic containers and set aside for a minimum time of 21 days, for the secular equilibrium to occur between {sup 226}Ra and its short lived descendants. The counting time was 80,000 seconds. Gamma energies used for determination of activity concentrations

Concentration of natural radionuclides (40K, 228Ra and 226Ra) in vegetables and fruits collected around Kudankulam, South India

International Nuclear Information System (INIS)

Mahiban Ross, E.; Feroz Khan, M.; Lenin Raj, Y.; Godwin Wesley, S.; Kumar, M.; Sundar Rajan, P.

2007-01-01

Baseline activity concentration of the natural radio nuclides 40 K, 228 Ra and 226 Ra in vegetables and fruits was determined around Kudankulam. In many of the samples, 228 Ra and 226 Ra was below minimum detection limit. 40 K was found to be more in leafy vegetables followed by pods, tubers and fleshy fruits. The highest accumulator among the matrices was the leafy vegetables with the geometric mean of 189.47 Bq.kg -1 fresh for vegetables and fruits with the geometric mean of 128.95 Bq.kg -1 fresh. 228 Ra activity in vegetables and fruits ranged from 0.074 to 1.153 and 0.074 to 0.131 Bq.kg -l fresh respectively. 226 Ra in vegetables and fruits ranged from BDL to 0.07 and BDL-.044 Bq.kg -l fresh respectively. 40 K in vegetables and fruits followed a log normal distribution. (author)

A rapid analysis of {sup 226}Ra in raw materials and by-products using gamma-ray spectrometry

Energy Technology Data Exchange (ETDEWEB)

Lim, Chung Sup; Chung, Kun Ho; Kim, Chang Jong; Ji, Young Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

A gamma-ray peak of {sup 226}Ra (186.2 keV) overlaps with one of {sup 235}U (185.7 keV) in a gamma-ray spectrometry system. Though reference peaks of {sup 235}U can be used to correct the peak interference of {sup 235}U in the analysis of {sup 226}Ra, this requires a complicated calculation process and a high limit of quantitation. On the other hand, evaluating {sup 226}Ra using the correction constant in the overlapped peak can make a rapid measurement of {sup 226}Ra without the complicated calculation process as well as overcome the disadvantage in the indirect measurement of {sup 214}Bi, which means the confinement of {sup 222}Rn gas in a sample container and a time period to recover the secular equilibrium. About 93 samples with 6 species for raw-materials and by-products were prepared to evaluate the activity of {sup 226}Ra using the correction constant. The results were compared with the activity of {sup 214}Bi, which means the indirect measurement of {sup 226}Ra, to validate the method of the direct measurement of {sup 226}Ra using the correction constant. The difference between the direct and indirect measurement of {sup 226}Ra was generally below about ± 20%. However, in the case of the phospho gypsum, a large error of about 50% was found in the comparison results, which indicates the disequilibrium between {sup 238}U and {sup 226}Ra in the materials. Application results of the contribution ratio of {sup 226}Ra were below about ± 10% . The direct measurement of {sup 226}Ra using the correction constant can be an effective method for its rapid measurement of raw materials and by-products because the activity of {sup 226}Ra can be produced with a simple calculation without the consideration of the integrity of a sample container and the time period to recover the secular equilibrium.

First 226Ra- 210Pb dating of a young speleothem

Science.gov (United States)

Condomines, M.; Rihs, S.

2006-10-01

Whereas the method based on the decrease of excess 210Pb has already been used to date young (Age determination of recent cave deposits using excess 210Pb — A new technique, Geophys. Res. Lett. 20 (1993) 603-606.]), this paper presents the first dating of a speleothem through the 226Ra- 210Pb method. Dating of a young hydrothermal stalagmite from the Mt Cornadore cave (St Nectaire, French Massif Central) was made possible by the high 226Ra and negligible 210Pb contents of such carbonates, formed by precipitation from CO 2-rich thermal waters. ( 210Pb/ 226Ra) ratios regularly increase with depth along the axis of the 33 cm long stalagmite. The age-depth relationship can be interpreted by two main phases of growth, with high but variable axial growth rates of 5.3 mm/yr from 1909 to 1967, and 2.6 mm/yr from 1967 to 1989 (alternatively, the oldest phase can be subdivided in three episodes with growth rates varying from 2 to 7 mm/yr). Thin-section examination reveals the presence of numerous laminae, indicating infra-annual variations. We suggest that this fine layered structure might reflect short-term fluctuations in drip waters, possibly induced by near-surface mixing between thermal and ground waters, and ultimately linked to the pluviometry. A detailed examination of this laminated structure combined with 226Ra- 210Pb dating could thus provide a high-resolution record of local paleohydrological fluctuations.

Dose-response relationships for bone tumors in beagles exposed to 226Ra and 90Sr

International Nuclear Information System (INIS)

Raabe, O.G.; Parks, N.J.; Book, S.A.

1981-01-01

385 dogs were exposed to 90 Sr in food from mid-gestation to 540 days of age. 243 young adult dogs were given eight fortnightly injections of 226 Ra. Comparison was made with available mouse and human 226 Ra bone tumor data. The major findings were: a) the occurrence of bone tumor related deaths was much less for 90 Sr than for 226 Ra exposed dogs. b) RBE for bone tumors from 90 Sr-Y varied as a function of average dose rate to bone. c) people require 10 times as long as mice and 3.6 times as long as dogs to develop 226 Ra-induced bone tumors at a given skeletal dose rate. d) based on the results, a practical threshold for bone cancer from 226 Ra was estimated to exist at cumulative doses of about 50-110 rad for dogs, mice and people. (author)

Ra-226 and Rn-222 in saline water compartments of the Aral Sea region

International Nuclear Information System (INIS)

Schettler, Georg; Oberhänsli, Hedi; Hahne, Knut

2015-01-01

Highlights: • 222 Rn and 226 Ra concentrations in different water compartments of the Aral Sea region. • 226 Ra-analysis based on 222 Rn-ingrowth versus MS-analysis after solid-phase extraction. • 226 Ra in different groundwater types of the Aral Sea Basin. • 222 Rn distribution in the Aral Sea, western basin. - Abstract: The Aral Sea has been shrinking since 1963 due to extensive irrigation and the corresponding decline in the river water inflow. Understanding of the current hydrological situation demands an improved understanding of the surface water/groundwater dynamics in the region. 222 Rn and 226 Ra measurements can be used to trace groundwater discharge into surface waters. Data of these radiometric parameters were not previously available for the study region. We determined 222 Rn activities after liquid phase extraction using Liquid Scintillation Counting (LSC) with peak-length discrimination and analyzed 226 Ra concentrations in different water compartments of the Amu Darya Delta (surface waters, unconfined groundwater, artesian water, and water profiles from the closed Large Aral Sea (western basin). The water samples comprise a salinity range between 1 and 263 g/l. The seasonal dynamics of solid/water interaction under an arid climate regime force the hydrochemical evolution of the unconfined groundwater in the Amu Darya Delta to high-salinity Na(Mg)Cl(SO 4 ) water types. The dissolved radium concentrations in the waters were mostly very low due to mineral over-saturation, extensive co-precipitation of radium and adsorption of radium on coexisting solid substrates. The analysis of very low 226 Ra concentrations (<10 ppq) at remote study sites is a challenge. We used the water samples to test and improve different analytical methods. In particular, we modified a procedure developed for the α-spectrometric determination of 226 Ra after solid phase extraction of radium using 3M Empore™ High Performance Extraction Disks (Purkl, 2002) for the

Development of a liquid scintillation method for in vitro determination of 226Ra and 228 Ra in bioassay samples

International Nuclear Information System (INIS)

Fernandes, Paulo Cesar P.; Sousa, Wanderson O.; Juliao, Ligia M.Q.C.; Dantas, Bernardo M.

2011-01-01

Radium isotopes are dispersed in the environment according to their physicochemical characteristics. The intake of 226 Ra and 228 Ra in humans can occur by inhalation and ingestion and the risk of internal exposure are related to their long half-lives, characteristics of the emission and biokinetics of the isotopes in the human body. The goal of this work is to develop a methodology for the analysis of 226 Ra and 228 Ra in excreta samples (urine and feces), using liquid scintillation technique. Excreta samples were provided by non-exposed humans for the purpose of standardizing the methodology and the establishment of a background level of radium excretion. Radium isotopes were concentrated and separated from the constituents of the sample by co-precipitation with barium sulphate. The precipitate of Ba(Ra)SO 4 was filtrated and weighted for the determination of the chemical yield. The filter containing the precipitate was transferred to a scintillation vial. In the scintillation vial, 8 mL of water, 8 mL of Instagel XF and 4 mL of UltimaGold were added, forming a gel suspension, after stirring the solution. The 226 Ra and 228 Ra activities were determined 21 days after the precipitation of samples. The samples were counted in a liquid scintillation spectrometer. The technique presented adequate sensitivity and reproducibility for the analysis of urine and feces. The activities of 226 Ra and 228 Ra in excreta samples provide useful information for the identification of the main route of intake and for the assessment of the internal exposure of occupationally exposed workers and inhabitants of high background areas. (author)

Bioavailability of radionuclides 226Ra, 228Ra and 210Pb present in the brazilian phosphate fertilizers and phosphogypsum

International Nuclear Information System (INIS)

Russo, Ana Carolina

2013-01-01

Phosphogypsum, also called gypsum, by-product of the phosphate fertilizer industry, can be used as soil conditioner since it provides improvements in the soil-plant system. However, this by-product concentrates radionuclides of the U and Th series, present in the phosphate rock used as raw material, which can impact the environment. In order to study the bioavailability of radionuclides, samples of phosphogypsum and phosphate fertilizers (monoammonium phosphate and triple superphosphate) were analyzed. The concentration of 226 Ra, 228 Ra and 210 Pb were determined by gamma spectrometry. The samples were leached with a mild EDTA solution and the radionuclides present in the final solution were determined by total alpha and beta counting on a gas flow proportional counter. The percentage of extraction varied from 1.6% to 1.7% for 210 Pb, from 0.5% to 1.4% for 226 Ra and from 0.1% to 1.0% for the 228 Ra in phosphogypsum samples. The low percentage of extraction obtained for the radionuclides can be partly explained by the low solubility of phosphogypsum, which ranged from 7.7% to 16%. For the monoammonium phosphate samples the percentage of extraction were less than 26% for 226 Ra, less than 10% for '2 28 Ra and less than 10% for 210 Pb. In spite of the high solubility of 77% of monoammonium phosphate in the EDTA solution, low concentrations of radionuclides were observed in the leached solution. For the triple superphosphate samples, the percentage of extraction was 2.3% for 226 Ra, 1.2% for 228 Ra and 11.3% for 210 Pb. In spite of the high solubility of 66% of triple superphosphate in the EDTA solution, low concentrations of radionuclides were observed in the leached solution. (author)

Transfer of 226Ra and 137Cs from tea leaves to drinking tea

International Nuclear Information System (INIS)

Fathivand, A. A.; Amidi, J.; Heravi, G. H.

2006-01-01

Two of the important radionuclides which are entered to environment and human diet are radium-226 ( 226 Ra) and cesium-137( 137 Cs). It is clear that the methods for preparation of foods such as peeling, washing, cooking or frying can affect the dose which is received by human due the to consumption of foodstuffs. An experiment has been performed at the environmental monitoring section of National Radiation Protection Department, aiming to measure the transfer of 226 Ra and 137 Cs from the tea leaves to drinking part of tea. Materials and Methods:Tea samples were pulverized to obtain a homogenous matrix which was weighed and placed In 1000 cm 3 Marinelli beaker. After making tea, the liquid tea and tea-discard were analyzed separately. Measurement of 226 Ra and 137 Cs was performed by gamma spectrometry system using a high purity germanium detector with 40% relative efficiency. The detector was shielded by 10 cm lead all sides with cadmium -copper as liners. Results: It was found that the activity concentration transferred from tea leaves to drinking tea for 137 Cs and 226 Ra are less than 2% and 17% respectively. Conclusion: On the basis of these measurements it seems that no significant levels of radioactivity of 226 Ra and 137 Cs can be found in drinking part of tea. The low concentration of the mentioned radionuclides in drinking tea is mostly due to tea dust and can be removed by its washing before preparing tea

Origin, quantities produced and ways of conditioning of special wastes in regional collection points

International Nuclear Information System (INIS)

Neider, R.

1983-01-01

Radioactive substances to be collected at regional collecting points are mostly related to the radionuclides H-3, Ra-226 and Th-232. These special wastes form a particular group of wastes including such solid wastes which do not contain volatile radionuclides yet cannot, for other reasons, be conditioned in accordance with the old Asse qualifications. (orig./DG) [de

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

Science.gov (United States)

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.

226Ra and 228Ra in the mixing zones of the Pee Dee River-Winyah Bay, Yangtze River and Delaware Bay Estuaries

International Nuclear Information System (INIS)

Elsinger, R.J.; Moore, W.S.

1984-01-01

226 Ra and 228 Ra have non-conservative excess concentrations in the mixing zones of the Pee Dee River-Winyah Bay estuary, the Yangtze River estuary, and the Delaware Bay estuary. Laboratory experiments, using Pee Dee River sediment, indicate desorption of 226 Ra to increase with increasing salinities up to 20 per mille. In Winyah Bay desorption from river-borne sediments could contribute almost all of the increases for both isotopes. Desorption adds only a portion of the excess 228 Ra measured in the Yangtze River and adjacent Shelf waters and Delaware Bay. In the Yangtze River the mixing zone extends over a considerable portion of the Continental Shelf where 228 Ra is added to the water column by diffusion from bottom sediments, while 226 Ra concentrations decrease from dilution. Diffusion of 228 Ra from bottom sediments in Delaware Bay primarily occurs in the upper part of the bay ( 228 Ra of 0.33 dpm cm -2 year was determined for Delaware Bay. (author)

Evaluation of the 226Ra transport by rivers sediments surroundings the brazilian uraniums mining and milling

International Nuclear Information System (INIS)

Azevedo, H.L.; Amaral, E.C.S.; Godoy, J.M.

1989-01-01

A study of the 226 Ra contamination of the rivers sediments surroundings the Brazilian uranium mining and milling was carried out. The total and mondetrital 226 Ra concentrations was determined as well as some preliminary speciations measurements. It was not observed increments in the nondetrital fraction when comparing with the pre operational results. The values indicated that the soluble form could be the main path of 226 Ra transport. However the critical sampling point supplied to influence from the chemical processing effluent show increments tht indicate to be mainly due to the presence of 226 Ra bound with barium sulphate. (author) [pt

Validation of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb measurements in soil and sediment samples through high resolution gamma ray spectrometry

Energy Technology Data Exchange (ETDEWEB)

Dias, Danila Carrijo da Silva; Silva, Nivaldo Carlos da; Bonifacio, Rodrigo Leandro; Guerrero, Eder Tadeu Zenun [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas

2013-07-01

Radionuclides found in ore extraction waste materials are a great source of concern regarding public health and environmental safety. One technique to determine the concentration of substances is high resolution gamma ray spectrometry using HPGe. Validating a measurement technique is essential to warrant high levels of quality to any scientific work. The Laboratory of Pocos de Caldas of the Brazilian Commission for Nuclear Energy partakes into a Quality Management System project, seeking Accreditation under ISO/IEC 17025 through the validation of techniques of chemical and radiometric analysis of environmental samples from water, soil and sediment. The focus of the Radon Laboratory at LAPOC is validation of Ra-226, Ra-228 and Pb-210 concentration determinations in soil and sediment through a gamma spectrometer system. The stages of this validation process included sample reception and preparation, detector calibration and sample analyses. Dried samples were sealed in metallic containers and analyzed after radioactive equilibrium between Ra-226 and daughters Pb-214 and Bi-214. Gamma spectrometry was performed using CANBERRA HPGe detector and gamma spectrum software Genie 2000. The photo peaks used for Ra-226 determination were 609 keV and 1020 keV of Bi-214 and 351 keV of Pb-214. For the Ra-228 determination a photopeak of 911 keV was used from its short half-life daughter Ac-228 (T1/2 = 6.12 h). For Pb-210, the photopeak of 46.5 keV was used, which, due to the low energy, self-absorption correction was needed. Parameters such as precision, bias/accuracy, linearity, detection limit and uncertainty were evaluated for that purpose. The results have pointed to satisfying results. (author)

226Ra and natural uranium in egyptian bottled mineral waters

International Nuclear Information System (INIS)

Higgy, R.H.

2000-01-01

Concentration levels of 226 Ra and natural uranium have been analysed bottled mineral water commercially available in egypt. 226 Ra was determined by applying a chemical procedure in which Ra was coprecipitated with Ba as sulphate. The precipitate was then dissolved with EDTA and then measured by liquid scintillation system, after mixing with a scintillation cocktail. Natural uranium was determined by applying a chemical procedure for uranium extraction using MIBK and then measured using laser fluorimeter system. The concentration values obtained were compared with concentrations reported by other countries and with reference values accepted for drinking water. Based on the consumption rate and the measured concentrations, the collective committed effective doses were calculated. In addition, Ca, Mg and Na were measured using Icp system and compared with some worldwide values

Uptake of endogenous and exogenous 226Ra by vegetables from soils of a highly radioactive region

International Nuclear Information System (INIS)

Lima, V.T.; Penna-Franca, E.

1988-01-01

The Pocos de Caldas Plateau is a weathered alkaline igneous intrusion where several radioactive anomalies (U and Th series) exist. Not only the local soils but also the edible vegetables produced in the region can present 226 Ra concentrations up to 10 times higher than those from areas of normal radioactivity. The aim of this work is to evaluate through greenhouse experiments, the uptake of endogenous and exogenous 226 Ra by carrots, brown beans and kale grown from four paired local natural and contaminated farm soils. Simultaneously, sequential selective extractions were performed to estimate the partitioning of 226 Ra among six geochemical fractions. The results showed that concentration ratios (CRs), related to plant dry weight, for endogenous and exogenous 226 Ra in soils, were of the order of 10 -2 -10 -1 and 10 -2 -10 0 respectively. The averages of 226 Ra exchangeable and residual fractions in soils were: 3.2% and 50.2% for endogenous and 15.4% and 6.0% for exogenous radium. The CRs calculated either in relation to total 226 Ra or to the exchangeable fraction in soils showed about the same variability. (author)

Determination of 228Th, 226Ra and 40K in Soil Using In-Situ GammaSpectrometer

International Nuclear Information System (INIS)

Bunawas; Wahyudi; Syarbaini; Untara

2000-01-01

Determination of natural radionuclide in latosol soil at six locationsaround PPTN Serpong by using Inspector portable gamma spectrometer with highpurity Germanium detector (HPGe) which has 26% relative efficiency had beenobtained. Radionuclides data of 228 Th, 226 Ra and 40 K were obtained in4 hours, shorter than laboratories analysis which needed 3 weeks. Thedifferences between in-situ measurement and laboratory were 3.6% to 56.2% forsix conditions of soil measured. According to the specific activity dataanalysis using statistic hypothesis, the result shows that the activity of 228 Th and 226 Ra are independent on location, but 40 K is dependent onlocation. (author)

Life-span studies in 226Ra-injected animals: Effect of low doses, effect of a decorporative treatment

International Nuclear Information System (INIS)

Schoeters, G.E.R.; Vanderborght, O.L.J.

1986-01-01

A life-span radiation effects study was performed in mice injected with several doses of 226 Ra. The study included 788 male C57Bl mice. For the removal of the 226 Ra, half the mice were treated daily with a diet 5% of which was sodium-alginate. The experiment revealed that mice that received the lowest dose of 226 Ra lived significantly longer than controls, and, despite appreciable skeletal removal of 226 Ra as a result of decorporative treatment, no biological benefit was observed in treated animals. 19 refs., 4 figs., 3 tabs

Salinity dependence of 226Ra adsorption on montmorillonite and kaolinite

International Nuclear Information System (INIS)

Shuji Tamamura; Takahiro Takada; Seiya Nagao; Masayoshi Yamamoto; Keisuke Fukushi

2014-01-01

The effect of NaCl concentration (10.0-1,000 mM) on 226 Ra adsorption was investigated in the presence of montmorillonite and kaolinite. A positive correlation was observed between the dissolved 226 Ra and NaCl concentrations in the presence of these adsorbents. Distribution coefficients decreased from the order of 10 4 to 10 0 (mL g -1 ) with an increase in NaCl concentration. Although the coefficients were higher for montmorillonite than kaolinite at lower NaCl concentrations, the trend was reversed at higher NaCl concentrations (≥500 mM) owing to the sharper reduction of the coefficient for montmorillonite with the increase in NaCl concentration. The rapid reduction was ascribed to higher negative charge density of montmorillonite, which leads the Ra 2+ adsorption mechanism to approach charge-compensating ion exchange. (author)

Concentrations and activity ratios of 228Ra and 226Ra in surface seawater along the Pacific coast of Japan

International Nuclear Information System (INIS)

Ohta, T.; Mahara, Y.; Kubota, T.; Sato, J.; Gamo, T.

2011-01-01

We measured the 228 Ra/ 226 Ra activity ratios in surface seawater along the Pacific coast of Japan at five ports around the island of Izu-Oshima (n = 29), at Atami in Sagami Bay (n = 13), and at Umizuri Park in Tokyo Bay (n = 14). We also conducted these measurements along a transect from the open Pacific Ocean across the Kuroshio to the mouth of Tokyo Bay (n = 7). The activity ratios decreased with increasing salinity of the sampling sites. The 228 Ra/ 226 Ra activity ratios in surface seawater along the coast gradually decreased after at the end of autumn and were lowest in winter and the beginning of spring. The surface salinity along the coast decreased from summer into autumn and increased from winter to the beginning of spring. The activity ratios decreased with the increase of salinity. The variation in activity ratios at the three coastal sites is possibly caused by differing contributions of surface seawater from the Kuroshio and surrounding open ocean. The different patterns and ranges of variation in the 228 Ra/ 226 Ra activity ratios in surface seawater at Izu-Oshima, Atami, and Umizuri Park may reflect both the amount of water from the Kuroshio and vicinity, and the local bathymetry, because continental shelf sediment is the source of Ra isotopes in surface seawater. (orig.)

Ra-226 collective dosimetry for surface waters in the uranium mining region of Pocos de Caldas

International Nuclear Information System (INIS)

Paschoa, A.S.; Sigaud, G.M.; Montenegro, E.C.; Baptista, G.B.

1980-01-01

Graphs of the collective dose equivalent for the whole body, bone, gastro-intestinal tract (lower large intestine), kidneys, and liver, via the pathways of drinking water and ingestion of food grown in irrigated fields are presented as a function of the 226 Ra concentrations in the surface waters of the Pocos de Caldas region. The collective dose equivalent calculated from the 226 Ra concentrations measured in the baseline studies are compared with those collective dose equivalent estimated from the projected higher 226 Ra concentrations in the river waters. The 226 Ra concentrations in river waters of the region are expected to be enhanced due to 226 Ra releases from uranium mining and milling operations. The dose equivalent commitment for the exposed population for the referred pathways is also estimated for the contribution of the mine during its predicted time of operation. The assumptions for the dose calculations are presented and the results obtained are discussed. (H.K.)

RA-226 concentration in water samples near uranium mines and in marine fishes

International Nuclear Information System (INIS)

Porntepkasemsan, B.

1987-11-01

Radium-226 and calcium were measured in water samples from the vicinity of three uranium mines and in fish samples collected from Puget sound, Washington State. The radium content of the samples were below the maximum permissible concentration 3 pCi/L for drinking water recommended by the Public Health Service and U.S. Environmental Protection Agency. The mean value of Ra-226 in water was 0.428 pCi/L and ranged from 0.043 to 1.552 pCi/L, whereas calcium content ranged from 3.0 to 190.0 mg/L. Ra-226 concentrations and calcium content in whole fish were 0.833-20.328 pCi/kg wet wt. and 114.1-259.3 mg/g ash, respectively. Results of the study indicated that Ra-226 concentration in water was correlated with calcium concentration but that this correlation was not observed in fish sample except English sole

238U-230Th-226Ra radioactive disequilibria in the products from 1707 eruption of Fuji volcano, Japan

International Nuclear Information System (INIS)

Kurihara, Yuichi; Takahashi, Masaomi; Sato, Jun

2008-01-01

Time scale of magmatic processes in the 1707 eruptive activity of Fuji volcano, Japan, was estimated by the 238 U- 230 Th- 226 Ra disequilibria observed in the 1707 volcanic products. The activity ratios of 226 Ra/ 230 Th in the products were larger than unity, being enriched in 226 Ra relative to 230 Th. The decay-corrected 226 Ra/ 230 Th activity ratio to the time of the eruption versus 238 U/ 230 Th activity ratio diagram for the 1707 volcanic products showed a positive correlation, suggesting that the 238 U/ 230 Th- 226 Ra disequilibria occurred during the magma genesis of Fuji volcano. The 230 Th- 226 Ra disequilibria in the 1707 volcanic products suggested that the time scale from the magma genesis to the eruption, including the melting of the mantle wedge, magma storage and magmatic differentiation from basalt to andesite, was less than 8000 years. (author)

Behavior of 226Ra in the aquatic environment of the uranium mine region of Pocos de Caldas, MG, Brazil

International Nuclear Information System (INIS)

Silva Amaral, E.C. da.

1979-08-01

A sampling and analytical program for 238 U, 226 Ra and 210 Pb was started, at first, in the uranium mine region, at Pocos de Caldas, MG, Brazil. Afterwards, the interaction was studied between 226 Ra and local river sediments and waters. Peliminary studies were also done on the mobility of 226 Ra retained on solid matter or soil, induced by local waters. Above normal concentrations of 238 U, 226 Ra and 210 Pb were found in local waters, sediments and plants collected on the imediate vicinity of the mine. 226 Ra distribution coefficients are on the order of 10 3 for the different samples assayed. It was concluded that, in the future, 226 Ra discharged into liquid environment should be only temporarily retained by sediments. Its transport by surface waters should be predominantly in the soluble form. 226 Ra should become the critical radionuclide in terms of internal radiation dose on the local population, due to its ingestion with water. 226 Ra retained on solid supports is mobilized by local waters and its solubilization is dependent on the volume of water passed through. (M.A.) [pt

228Ra and 226Ra measurement on a BaSO4 co-precipitation source

International Nuclear Information System (INIS)

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

2015-01-01

One of the most commonly-used methods for determination of 226 Ra, particularly in water samples, utilises co-precipitation of Ra with BaSO 4 , followed by microfiltration to produce a source for alpha counting. This paper describes two extensions to BaSO 4 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 BaSO 4 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 BaSO 4 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. - Highlights: • We developed two methods for 228 Ra measurement on Ba(Ra)SO 4 co-precipitation sources. • Measurement by gamma spectrometry using the daughter 228 Ac is rapid. • Detection limits are suitable for assessment of drinking water quality. • The second approach uses alpha spectrometry on a separated Th fraction. • This is more sensitive than gamma spectrometry after an ingrowth period greater than about 1 month

The study of 226Ra concentration in Teheran's pasteurized milk

International Nuclear Information System (INIS)

Khademi, B.; Sekhavat, A.; Movahed Shari'atpanahi, J.

1975-01-01

A study of 226 88 Ra concentration in pasteurized milk distributed in Tehran during 1970-72 was accomplished. The Ash resulting from the milk was 4.5 to 5.5 gr., which might be due to poor nourishment of the animals. These results are compared with the Ra concentration in France and Puerto Rico

Development of a liquid scintillation method for in vitro determination of {sup 226}Ra and {sup 228} Ra in bioassay samples

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Paulo Cesar P.; Sousa, Wanderson O.; Juliao, Ligia M.Q.C.; Dantas, Bernardo M., E-mail: pcesar@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2011-07-01

Radium isotopes are dispersed in the environment according to their physicochemical characteristics. The intake of {sup 226}Ra and {sup 228}Ra in humans can occur by inhalation and ingestion and the risk of internal exposure are related to their long half-lives, characteristics of the emission and biokinetics of the isotopes in the human body. The goal of this work is to develop a methodology for the analysis of {sup 226}Ra and {sup 228}Ra in excreta samples (urine and feces), using liquid scintillation technique. Excreta samples were provided by non-exposed humans for the purpose of standardizing the methodology and the establishment of a background level of radium excretion. Radium isotopes were concentrated and separated from the constituents of the sample by co-precipitation with barium sulphate. The precipitate of Ba(Ra)SO{sub 4} was filtrated and weighted for the determination of the chemical yield. The filter containing the precipitate was transferred to a scintillation vial. In the scintillation vial, 8 mL of water, 8 mL of Instagel XF and 4 mL of UltimaGold were added, forming a gel suspension, after stirring the solution. The {sup 226}Ra and {sup 228}Ra activities were determined 21 days after the precipitation of samples. The samples were counted in a liquid scintillation spectrometer. The technique presented adequate sensitivity and reproducibility for the analysis of urine and feces. The activities of {sup 226}Ra and {sup 228}Ra in excreta samples provide useful information for the identification of the main route of intake and for the assessment of the internal exposure of occupationally exposed workers and inhabitants of high background areas. (author)

Inventory of 226Ra, 228Ra and 210Pb in marine sediments cores of Southwest Atlantic Ocean

International Nuclear Information System (INIS)

Costa, Alice M.R.; Oliveira, Joselene de; Figueira, Rubens C.L.; Mahiques, Michel M.; Sousa, Silvia H.M.

2015-01-01

210 Pb (22.3 y) is a radioactive isotope successfully applied as tracer of sediment dating of the last 100-150 years. The application of 226 Ra and 228 Ra as paleoceanographic tracers (half-lives of 1,600 y and 5.7 y, respectively) also gives some information of ocean's role in past climate change. In this work, it was analyzed 2 sediment cores collect at Southwest Atlantic Ocean. The sediments samples were freeze-dried and acid digested in microwave. It was carried out a radiochemical separation of 226 Ra, 228 Ra and 210 Pb and performed a gross alpha and gross beta measurement of both precipitates Ba(Ra)SO 4 and PbCrO 4 in a low background gas-flow proportional counter. Activity concentrations of 226 Ra ranged from 45 Bq kg -1 to 70 Bq kg -1 in NAP-62 and from 57 Bq kg -1 to 82 Bq kg -1 in NAP-63 samples. The concentration of 228 Ra varied between 37 Bq kg -1 and 150 Bq kg -1 in NAP-62 and between 23 Bq kg -1 and 111 Bq kg -1 in NAP-63 samples. The concentration of total 210 Pb ranged from 126 Bq kg -1 to 256 Bq kg -1 in NAP-62 and from 63 Bq kg -1 to 945 Bq kg -1 in NAP-63 samples. Results of 210 Pb uns varied from 68 Bq kg -1 to 192 Bq kg -1 for NAP-62, while varied from <4.9 Bq kg -1 to 870 Bq kg -1 in NAP-63 profile. Increased values of 210 Pb uns were found on the top of both NAP-62 and NAP- 63 sediment profile. (author)

U-isotopes and "2"2"6Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas

International Nuclear Information System (INIS)

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

2016-01-01

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 ("2"3"8U, "2"3"5U and "2"3"4U) and "2"2"6Ra by alpha spectrometry were determined. The activity concentration of "2"3"8U 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 "2"3"4U/"2"3"8U 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. "2"2"6Ra 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 "2"2"6Ra/"2"3"4U 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). "2"2"6Ra 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 "2"3"4U/"2"3"8U activity ratios, probably due to fast uniform bulk

Simple method for the determination of 210Pb and 226Ra in waters

International Nuclear Information System (INIS)

Canoba, Analia C.; Gnoni, Gabriela A.

2006-01-01

In this work a method for the separation is described and the determination of the radionuclides 226 Ra and 210 Pb in samples of environmental waters. The determination of 210 Pb consists in how the precipitation of PbSO 4 (lead sulfate) and the measurement by liquid scintillation. The determination of 226 Ra is made for co-precipitation with BaSO 4 (barium sulfate), emanation of 222 Rn in toluene and its measurement by liquid scintillation. Both processes are fast, simple and they utilize accessible reagents and of low cost. In the case of the determination of 210 Pb, the parameters related to the separation and measurement was optimized. In the case of the decision of 226 Ra, was considered the technique already utilized by the laboratory for the measurements of this radionuclide. (author) [es

MSFIA-LOV system for {sup 226}Ra isolation and pre-concentration from water samples previous radiometric detection

Energy Technology Data Exchange (ETDEWEB)

Rodríguez, Rogelio [Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, Cra. Valldemossa km 7.5, 07122, Palma (Spain); Environment and Energy Department, Advanced Materials Research Center (CIMAV) S.C., Miguel de Cervantes 120, Chihuahua, Chih. 31136 (Mexico); Borràs, Antoni [Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, Cra. Valldemossa km 7.5, 07122, Palma (Spain); Leal, Luz [Environment and Energy Department, Advanced Materials Research Center (CIMAV) S.C., Miguel de Cervantes 120, Chihuahua, Chih. 31136 (Mexico); Cerdà, Víctor [Department of Chemistry, University of the Balearic Islands, Cra. Valldemossa km 7.5, 07122, Palma (Spain); Ferrer, Laura, E-mail: laura.ferrer@uib.es [Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, Cra. Valldemossa km 7.5, 07122, Palma (Spain)

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 {sup 226}Ra from drinking and natural water samples has been developed. The analytical protocol combines two different procedures: the Ra adsorption on MnO{sub 2} and the BaSO{sub 4} co-precipitation, achieving more selectivity especially in water samples with low radium levels. Radium is adsorbed on MnO{sub 2} deposited on macroporous of bead cellulose. Then, it is eluted with hydroxylamine to transform insoluble MnO{sub 2} to soluble Mn(II) thus freeing Ra, which is then coprecipitated with BaSO{sub 4}. The {sup 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{sup −1}). Besides, it has been satisfactorily applied to different types of water matrices (tap, mineral, well and sea water). The {sup 226}Ra minimum detectable activities (LSC: 0.004 Bq L{sup −1}; LBPC: 0.02 Bq L{sup −1}) attained by this system allow to reach the guidance values proposed by the relevant international agencies e.g. WHO, EPA and EC. - Highlights: • Automatic, rapid and selective method for {sup 226}Ra extraction/pre-concentration from water. • MSFIA-LOV system performs a sample clean-up prior to {sup 226}Ra radiometric detection. • {sup 226}Ra sample preparation allows using two radiometric detectors (LBPC and LSC). • Environmental levels of {sup 226}Ra are easily quantified. • High sensitivity and selectivity are achieved, reaching the

A sequential and fast method for low level of 226Ra , 228Ra, 210Pb e 210Po in mine effluents and uranium processing plant

International Nuclear Information System (INIS)

Taddei, M.H.T.; Taddei, J.F.A.C.

2005-01-01

Due to biological risk and long half lives, the radionuclides 228 Ra, 226 Ra, 210 Pb and 210 Po should be frequently monitored to check for any environmental contamination around mines and uranium plants. Currently, the methods used for the determination of these radionuclides take about thirty days to reach the radioactive equilibrium of the 210 Pb and 226 Ra daughter's. The evaluation of effluent discharges and leakage of deposits to water bodies in monitoring programs, require quick answers to implement corrective measures. Thereby fast determination methods must be implemented. This work presents a fast and sequential method to, in three days, determine accurately and sensitively, 226 Ra, 228 Ra, 210 Pb, 210 Po, in water and effluent samples

Study of natural radionuclides - {sup 226}Ra, {sup 228}Ra and {sup 210}PB - in marine sediment cores from Southwest Atlantic during the Holocene; Estudo dos radionuclideos naturais - Ra226, Ra-228 e Pb-210 - em alguns registros sedimentares do Atlantico sudoeste ao longo do holoceno

Energy Technology Data Exchange (ETDEWEB)

Costa, Alice Miranda Ribeiro

2016-07-01

Natural radionuclides from {sup 238}U and {sup 232}Th series have been successfully applied as tracers of environmental process and climate changes. The {sup 210}Pb (half-life of 22.2 years) is used in the geochronological dating technique of sediment cores of the last 100-150 years, and its respective sedimentation rate determination. The study of {sup 226}Ra and {sup 228}Ra concentrations (half-lives of 1,600 years and 5.75 years, respectively) helps calculate the activity of {sup 210}Pb in excess in the environment, besides being important tracers of marine processes, as ground water discharge. In this work it was determined the activity concentrations of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb in four short marine cores collected since the continental platform to upper slope of Southwest Atlantic Ocean. Taking into account the results obtained, sedimentation rates and the ages of each sediment layer were determined using the geochronological dating method with {sup 210}Pb. All sediment samples were total acid digested in microwave. The sequential radiochemical separation of {sup 226}Ra, {sup 228}Ra, {sup 210}Pb were performed, obtaining in the end the precipitation of Ba(Ra)SO{sub 4} and PbCrO{sub 4}. The gross α measurements of {sup 226}Ra and gross β measurements of {sup 228}Ra and {sup 210}Pb from the precipitates were carried out in a gas-flow low background proportional counter. Concerning all cores analyzed, the activities concentrations of {sup 226}Ra ranged from 14 Bq.kg{sup -1} to 154 Bq.kg{sup -1}; the concentrations of {sup 228}Ra ranged from 17 Bq.kg{sup -1} to 45 Bq.kg{sup -1}; and the concentrations of {sup 210}Pb ranged from 20 Bq.kg{sup -1} to 2,073 Bq.kg{sup -1}. High values of {sup 210}Pb were observed on the top of all the cores studied, mainly related to atmospheric deposition. The results obtained in this work were of the same order of magnitude of those reported in the literature available on non contaminated areas of Southeast

Bioavailability of radionuclides {sup 226}Ra, {sup 228}Ra and {sup 210}Pb present in the brazilian phosphate fertilizers and phosphogypsum; Avaliacao da biodisponibilidade dos radionuclideos {sup 226}Ra, {sup 228}Ra e {sup 210}Pb presentes nos fertilizantes fosfatados e no fosfogesso de procedencia nacional

Energy Technology Data Exchange (ETDEWEB)

Russo, Ana Carolina

2013-08-01

Phosphogypsum, also called gypsum, by-product of the phosphate fertilizer industry, can be used as soil conditioner since it provides improvements in the soil-plant system. However, this by-product concentrates radionuclides of the U and Th series, present in the phosphate rock used as raw material, which can impact the environment. In order to study the bioavailability of radionuclides, samples of phosphogypsum and phosphate fertilizers (monoammonium phosphate and triple superphosphate) were analyzed. The concentration of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb were determined by gamma spectrometry. The samples were leached with a mild EDTA solution and the radionuclides present in the final solution were determined by total alpha and beta counting on a gas flow proportional counter. The percentage of extraction varied from 1.6% to 1.7% for {sup 210}Pb, from 0.5% to 1.4% for {sup 226}Ra and from 0.1% to 1.0% for the {sup 228}Ra in phosphogypsum samples. The low percentage of extraction obtained for the radionuclides can be partly explained by the low solubility of phosphogypsum, which ranged from 7.7% to 16%. For the monoammonium phosphate samples the percentage of extraction were less than 26% for {sup 226}Ra, less than 10% for '2{sup 28}Ra and less than 10% for {sup 210}Pb. In spite of the high solubility of 77% of monoammonium phosphate in the EDTA solution, low concentrations of radionuclides were observed in the leached solution. For the triple superphosphate samples, the percentage of extraction was 2.3% for {sup 226}Ra, 1.2% for {sup 228}Ra and 11.3% for {sup 210}Pb. In spite of the high solubility of 66% of triple superphosphate in the EDTA solution, low concentrations of radionuclides were observed in the leached solution. (author)

Determination of 226Ra contamination depth in soil using the multiple photopeaks method

International Nuclear Information System (INIS)

Haddad, Kh.; Al-Masri, M.S.; Doubal, A.W.

2014-01-01

Radioactive contamination presents a diverse range of challenges in many industries. Determination of radioactive contamination depth plays a vital role in the assessment of contaminated sites, because it can be used to estimate the activity content. It is determined traditionally by measuring the activity distributions along the depth. This approach gives accurate results, but it is time consuming, lengthy and costly. The multiple photopeaks method was developed in this work for 226 Ra contamination depth determination in a NORM contaminated soil using in-situ gamma spectrometry. The developed method bases on linear correlation between the attenuation ratio of different gamma lines emitted by 214 Bi and the 226 Ra contamination depth. Although this method is approximate, but it is much simpler, faster and cheaper than the traditional one. This method can be applied for any case of multiple gamma emitter contaminant. -- Highlights: • The multiple photopeaks method was developed for 226 Ra contamination depth determination using in-situ gamma spectrometry. • The method bases on linear correlation between the attenuation ratio of 214 Bi gamma lines and 226 Ra contamination depth. • This method is simpler, faster and cheaper than the traditional one, it can be applied for any multiple gamma contaminant

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

Science.gov (United States)

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

Quantification of 235 U and 226 Ra in soil samples by means of Gamma spectroscopy

International Nuclear Information System (INIS)

Quintero P, E.; Rojas M, V.P.; Montes M, F.R.; Gaso P, M.I.; Cervantes N, M.L.

2000-01-01

In this work it is presented the Gamma Spectroscopy method which is realized in the Environmental Radiological Surveillance Laboratory using the option of deconvolution of a commercial software for the quantification of 235 U and 226 Ra; also is presented the method for the 226 Ra correction activity. (Author)

226Ra and 228Ra tracer study on nutrient transport in east coastal waters of Hainan Island, China

Directory of Open Access Journals (Sweden)

Ni Su

2011-06-01

Full Text Available Material fluxes (e.g., nutrients from coastal waters to offshore areas play an important role in controlling the water quality of the adjacent sea areas not only by increasing nutrient concentration but also by changing nutrient structures. In this study, naturally occurring isotopes, 226Ra and 228Ra, were measured with the alpha spectrometry in the Wenjiao-Wenchang and Wanquan estuaries and adjacent sea areas along the east coast of Hainan Island. The excess 226Ra and 228Ra activities were observed by comparison with the values derived from the conservative mixing of freshwater and seawater end-members in both estuaries. Using a one-dimensional diffusion model, the horizontal eddy diffusion coefficient of 3.16 x 105 cm2/s, for nutrients diffusing from their sources, was derived from 228Ra activities. Consequently, the corresponding nutrient fluxes flowing into the coastal waters were assessed. The results can provide useful information for the study of the mixing and exchange processes of coastal waters as well as dissoluble pollutant transport in this sea area.

Natural uranium and 226Ra in bottled potable waters of Argentina

International Nuclear Information System (INIS)

Bomben, Ana M.; Palacios, Miguel A.

2001-01-01

This paper presents the results obtained of the measurement of the natural uranium and 226 Ra concentrations carried out on 345 drinking water samples coming from different provinces of Argentina. The samples were collected from tap water systems and private wells. Six bottled mineral waters samples, selected from those most extensively consumed, were also analyzed. The natural uranium concentration was determined by a fluorimetric procedure and 226 Ra by the 222 Rn emanation technique and liquid scintillation counting. Values ranging from 0,03 to 50 μg L -1 of natural uranium and concentrations up to 22 mBq L -1 were found in the drinking water samples analyzed. Natural uranium concentrations from 0,04 to 3,8 μg L -1 and 226 Ra concentrations up to 2,4 mBq L -1 were measured in the bottled mineral waters samples. Based on the water intake rate and the measured concentrations of both radionuclides analyzed, an annual collective effective dose of 1,5 man Sv and an average committed effective dose of 0,5 μSv a -1 , were calculated for the City of Buenos Aires inhabitants. (author)

The 226Ra isotope activities in ground water samples drawn of two wells from the Meridional Pluton, Morungaba Granitoids, eastern Sao Paulo State; Atividades do 226Ra em aguas subterraneas extraidas de dois pocos localizados no pluton meridional, granitoides de Morungaba, SP

Energy Technology Data Exchange (ETDEWEB)

Lucas, Fabio de Oliveira; Silva Junior, Mario Goncalves da; Bertolla, Luciana; Ribeiro, Fernando Brenha [Sao Paulo Univ., SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Geofisica]. E-mail: brenha@iag.usp.br

2005-07-01

The 226Ra activities, both in solution and associated with suspended solids, were measured in ground water samples drawn from two wells drilled in a fractured granitic aquifer from the Meridional Pluton, Morungaba Granitoids, eastern Sao Paulo State. The 226Ra isotope activities were measured in a sequence of samples collected about one month apart between March, 2003 and April 2004. The 226Ra activities were measured by radon gas emanometry. The mean dissolved 226Ra activity concentration activities observed in the two wells were (44.9 {+-} 7.1) mBq/L and (51.6 {+-} 8.8) mBq/L. The 226Ra activity of the suspend solids in a liter of these waters varied between (0,6 {+-} 0,1) mBq and (13 {+-} 1) mBq, respectively. (author)

226Ra concentrations in crayfish tissues, water, and sediments from the Serpent River Basin in Northeastern Ontario, Canada

International Nuclear Information System (INIS)

Alikhan, M.A.

1996-01-01

Lower Serpent River, as well as Elliot, McCarthy and McCabe lakes had highest 226 Ra contamination, Chrisman, Quirke and Whiskey lakes a moderate one, Flack and Semiwhite lakes and the 'distant' control, Lake Wanapitei, the lowest. 226 Ra activity in Cambarus robustus tissues was directly related to their background levels. Thus, concentration coefficient (tissue/sediment concentrations) for 226 Ra ranged from 0.53 to 0.74 in highly contaminated Elliot and McCarthy lakes, 0.28 to 0.59 in moderately contaminated Quirke and Whiskey lakes, and from 0.27 to 3.44 in least contaminated Semiwhite and Flack lakes. Among various organs analysed, exoskeleton showed the highest (43.04 - 90.69%) and the tail muscles the lowest (2.95 -17.14%) 226 Ra activity. 226 Ra concentrations in the alimentary canal were considered a part of the ambient environment as they had not been absorbed

226Ra intake in the population from Bucharest during the past ten years

International Nuclear Information System (INIS)

Toader, M.; Vasilache, R.A.; Tomulescu, V.

1998-01-01

During 1986-1996 the content of several radionuclides, including 226 Ra, in the basic foodstuffs and in drinking water was determined. Based on these data and on the data concerning the constituents of the diet in Romania, the 226 Ra intake by the population of Bucharest was estimated for the last ten years, and the doses due to this intake were calculated. The results are presented in graphs and tables, and some general conclusions are drawn. (A.K.)

Adsorption of 241Am and 226Ra from natural water by wood charcoal

International Nuclear Information System (INIS)

Miro, C.; Baeza, A.; Salas, A.; Pastor-Valle, J.F.; Pastor-Villegas, J.

2008-01-01

The adsorption of 241 Am and 226 Ra from natural water by a granulated wood charcoal was investigated as a function of the solution pH, in the range 4-10, and of the water flow, in the range 3.5-42 cm 3 /min. The percentage adsorption of 241 Am (fairly constant at >80% for all pHs) was greater than that of 226 Ra (which increased with increasing pH from ∼40% up to >80%). The results are explained by considering the different species of each radionuclide present at the pH values of the solution at the end of the adsorbent column, and the pH of the point of zero charge of the adsorbent. At pH 6, the elimination of 241 Am from natural water was independent of the water flow, while the elimination of 226 Ra declined linearly as the flow rate was increased

Spreading of water masses and regeneration of silica and sup(226)Ra in the Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

DileepKumar, M.; Yuan-Hui, Li

The magnitudes of silica and sup(226) RA inputs to water (through particle regeneration, in situ, and from sediments) and the validity of observed Si and sup(226) Ra as tracers of water masses and advective processes were examined in the Indian...

Summary of dosimetry, pathology, and dose response for bone sarcomas in beagles injected with 226Ra

International Nuclear Information System (INIS)

Wrenn, M.E.; Taylor, G.N.; Stevens, W.

1985-01-01

One hundred and sixty dogs given single intravenous injections of 226 Ra citrate at age 17 +/- 2 months (116) or a non-radioactive solution (44 controls) were part of a 30 year long experiment to determine the relative radiotoxicity of injected 226 Ra and 239 Pu. The authors report a preliminary summary of the results of the 226 Ra study. Skeletal development of the beagles used in this study is analogous to a young adult human, simulating that of a young adult radium dial painter or occupationally exposed person. Injected dosage of 226 Ra, average skeletal dose, and number of dogs and dogs developing bone sarcomas in each group are presented. The lowest nominal injected activity was 0.007 μCi/kg. Each of the 8 dosage levels contained about 12 dogs, except for 23 dogs at 0.06 μCi/kg and 25 dogs at 0.02 μCi/kg

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

Science.gov (United States)

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

2014-12-01

226Ra excesses in mafic arc magmas are generally attributed to recent (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 may also explain 226Ra deficits at some other SVZ volcanoes. Thus (226Ra-230Th) in erupted magmas reflect modification of mantle-derived signatures by open-system magmatic processes in the crust. 1Sigmarsson et al., 2002, Earth and Planet. Sc. Lett. 196, 189-196. 2 Reubi et al., 2011, Earth and Planet. Sc. Lett. 303, 37-47.

Quantification of {sup 235} U and {sup 226} Ra in soil samples by means of Gamma spectroscopy; Cuantificacion de {sup 235} U y {sup 226} Ra en muestras de suelo por medio de espectrometria gamma

Energy Technology Data Exchange (ETDEWEB)

Quintero P, E.; Rojas M, V.P.; Montes M, F.R.; Gaso P, M.I.; Cervantes N, M.L. [Gerencia de Innovacion Tecnologica, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

2000-07-01

In this work it is presented the Gamma Spectroscopy method which is realized in the Environmental Radiological Surveillance Laboratory using the option of deconvolution of a commercial software for the quantification of {sup 235} U and {sup 226} Ra; also is presented the method for the {sup 226} Ra correction activity. (Author)

Intake of 226Ra, 210Pb and 210Po with food in Poland

International Nuclear Information System (INIS)

Pietrzak-Flis, Z.; Chrzanowski, E.; Dembinska, S.

1997-01-01

Intake with food and water of 226 Ra, 210 Pb and 210 Po was determined for an adult population in regions of central, northern and northeastern Poland. The content of radionuclides was determined in the daily diet and, in the central region, also in foodstuffs and drinking water. The annual intake with foodstuffs was estimated on the basis of their average annual consumption. The 226 Ra intake in northeastern Poland was approximately 17% higher than the overall average, correlating well with the higher concentration of this radionuclide in the soil. The 210 Po/ 210 Pb ratio was close to unity in the continental regions, whereas at the Baltic Sea coast it was approximately 1.5. The latter value can be ascribed to a larger consumption of fish for which the 210 Po/ 210 Pb ratio was found to be approximately 10. In central Poland the largest intake of 226 Ra was with flour and vegetables (contribution approx. 60%), the largest intake of 210 Pb was with flour and meat (approx. 50%) and the largest intake of 210 Po was with fish (approx. 34%). From the intake and dose coefficient, annual effective doses were calculated. The dose from 210 Pb and 210 Po was approx. 54 μSv year -1 , and the dose from 226 Ra was approx. 4 μSv year -1

A Procedure for the Rapid Determination of 226Ra and 228Ra in Drinking Water by Liquid Scintillation Counting

International Nuclear Information System (INIS)

2014-01-01

Since 2004, the environment programme of the IAEA has included activities aimed at the development of a set of procedures for the determination of radionuclides in terrestrial environmental samples. Reliable, comparable and ‘fit for purpose’ results are essential requirements for any decision based on analytical measurements. For the analyst, tested and validated analytical procedures are extremely important tools for the production of such data. For maximum utility, such procedures should be comprehensive, clearly formulated and readily available to both the analyst and the customer. This publication describes a procedure for the rapid determination of 226 Ra and 228 Ra in drinking water. The determination of radium in drinking water is important for protecting human health, since the consumption of drinking water containing radium may lead to an accumulation in the body, contributing to the radiological dose. The method is based on the separation of 226 Ra and 228 Ra from interfering elements using PbSO 4 and Ba(Ra)SO 4 coprecipitation steps. The isotopes 226 Ra and 228 Ra are then determined by liquid scintillation counting. The procedure is expected to be of general use to a wide range of laboratories, including the laboratories of the Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) network, both in emergency situations and for routine environmental monitoring purposes. The method was established after an extensive review of papers from the scientific literature, and was tested and validated in terms of repeatability and trueness (relative bias) in accordance with International Organization for Standardization guidelines. Reproducibility tests were performed at expert laboratories. The calculation of massic activities, uncertainty budget, decision threshold and detection limit are also described

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

International Nuclear Information System (INIS)

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

2012-01-01

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. - Highlights: ► 226 Ra affects the transcription of genes in Atlantic cod embryonic cells. ► 226 Ra may induce oxidative stress and apoptosis in fish embryonic cells. ► 226 Ra not expected to pose a major threat to early life stages of marine fish.

Estimation of annual effective dose from 226Ra 228Ra due to consumption of foodstuffs by inhabitants of high level natural radiation of Ramsar, Iran

International Nuclear Information System (INIS)

Fathivand, A.A.; Asefi, M.; Amidi, A.

2005-01-01

Full text: A knowledge of natural radioactivity in man and his environment is important since naturally occurring radionuclides are the major source of radiation exposure to man. Radioactive nuclides present in the natural environment enter the human body mainly through food and water.Besides, measurement of naturally occurring radionuclides in the environment can be used not only as a reference when routine releases from nuclear installation or accidental radiation exposures are assessed, but also as a baseline to evaluate the impact caused by non-nuclear activities. In Iran, measurement of natural and artificial radionuclides in environmental samples in normal and high-background radiation areas have been performed by some investigators but no information has been available on 226 Ra and 228 Ra in foodstuffs. Therefore we have started measurements of 226 Ra and 228 Ra in foodstuffs of Ramsar which is a coastal city in the north part of Iran and has been known as one of the world's high level natural radiation areas, using low level gamma spectrometry measurement system .The results from our measurements and food consumption rates for inhabitants of Ramsar city have been used for the estimation of annual effective dose due to consumption of foodstuffs by inhabitants of Ramsar city. A total of 33 samples from 11 different foodstuffs including root vegetables (beetroot), leafy vegetables (lettuce, parsley and spinach) and tea, meat,chicken, pea,broad bean, rice, and cheese were purchased from markets and were analyzed for their 226 Ra and 228 Ra concentrations. The highest concentrations of 226 Ra and 228 Ra were determined in tea samples with 1570 and 1140 mBq kg -1 respectively and the maximum estimated annual effective dose from 226 Ra and Ra due to consumption foodstuffs were determined to be 19.22 and 0.71 μSv from rice and meat samples respectively

Measurement of Ra-226 in building materials, with a Na I (Tl) scintillation counter

International Nuclear Information System (INIS)

Vallejo, L.R.; Fuenteseca, J.W.; Rivera, C.A.; Aros, F.H.

1992-01-01

Ra-226 concentration in building materials is determined using gamma-ray spectrometry. Ra-226 contained in sundry materials employed in the construction of dwelling houses and public buildings in Antofagasta city is determined by counting the Pb-214 peaks at 295 KeV and 352 keV, and the Bi-214 peak at 609 keV recorded by means of a 7.5-cm Nal (TI) scintillation counter. (author)

Collective excitations in the transitional nuclei /sup 224,226,228,230 /Ra

CERN Document Server

Kurcewicz, W; Kaffrell, N; Nyman, G H; Ruchowska, E

1981-01-01

The gamma -rays following the beta -decay of /sup 224,226,228,230/Fr have been investigated by means of gamma -ray singles (including multispectrum analysis) and gamma gamma coincidence measurements using Ge(Li) spectrometers. The study of the excited levels in /sup 224,226,228,230/Ra is focused on the properties of collective states. The analysis of the results leads one to the conclusion that a ground- state octupole deformation is the most likely explanation for the special features of the collective excitations in Ra and some neighbouring nuclei in the N136 region. (15 refs).

The role of the Ganges-Brahmaputra mixing zone in supplying barium and 226Ra to the Bay of Bengal

International Nuclear Information System (INIS)

Carroll, J.; Falkner, K.K.; Brown, E.T.; Moore, W.S.

1993-01-01

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 x 10 12 kg/yr (Milliman and Meade, 1983). Barium and 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 226 Ra fluxes to the ocean. Water samples for barium and 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 226 Ra to seawater. The release of barium and 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 226 Ra from the Ganges-Brahmaputra mixing zone were also derived. The fluxes of barium and 226 Ra are 5.3 x 10 8 mol barium/yr and 9.5 x 10 14 dpm radium/yr. The first silicate and phosphate mixing profiles for this system are reported. 29 refs., 6 figs., 3 tabs

Elimination of natural uranium and 226Ra from contaminated waters by rhizofiltration using Helianthus annuus L

International Nuclear Information System (INIS)

Vera Tome, F.; Blanco Rodriguez, P.; Lozano, J.C.

2008-01-01

The elimination of natural uranium and 226 Ra from contaminated waters by rhizofiltration was tested using Helianthus annuus L. (sunflower) seedlings growing in a hydroponic medium. Different experiments were designed to determine the optimum age of the seedlings for the remediation process, and also to study the principal way in which the radionuclides are removed from the solution by the sunflower roots. In every trial a precipitate appeared which contained a major fraction of the natural uranium and 226 Ra. The results indicated that the seedlings themselves induced the formation of this precipitate. When four-week-old seedlings were exposed to contaminated water, a period of only 2 days was sufficient to remove the natural uranium and 226 Ra from the solution: about 50% of the natural uranium and 70% of the 226 Ra were fixed in the roots, and essentially the rest was found in the precipitate, with only very small percentages fixed in the shoots and left in solution

Evaluation of the activity concentration of 226Ra, 228Ra and 210Pb in sediments from Antarctica in the Admiralty Bay region

International Nuclear Information System (INIS)

Mora, Tamires de A.; Oliveira, Joselene de; Figueira, Rubens C.L.; Mahiques, Michel M.; Sousa, Silvia H.M.

2015-01-01

In this study, we performed the radiochemical characterization of a sedimentary record (1B profile), collected in the vicinity of Admiralty Bay, King George Island in Antarctic Operation XXXI (January/2013). The activities of 226 Ra, 228 Ra and 210 Pb were determined by the counting of gross alpha and gross beta activities in the precipitates of Ba(Ra)SO 4 and PbCrO 4 . Those measurements were carried out in a low background gas flow proportional detector. The 226 Ra and 228 Ra were measured after 21 days of the final precipitation. The 210 Pb activity was determined after 10 days of the precipitation date by gross beta counting of its 210 Bi decay product. The activity concentration of 226 Ra ranged from 11±1 (mBq g-1) to 54±3 (mBq g -1 ), and the 228 Ra ranged from 48±5 (mBq g -1 ) to 155±16 (mBq g -1 ). The activity concentration of 210 Pb varied from 8±1 (mBq g -1 ) to 458±46 (mBq g -1 ), while unsupported 210 Pb ranged from 6±1 (mBq g -1 ) to 434±65 (mBq g -1 ). The 210 Pb concentrations in sediments have often been used to dating events like deposition and accumulation in various marine environments. Taking into account the results of 210 Pb and 226 Ra activities obtained in testimony-1B it was estimated the unsupported 210 Pb activity which was applied to the CIC geochronological dating model (Constant Initial Concentration). Based in these data, the sedimentation rate obtained was 0.63±0.02 cm year -1 . (author)

Plant/soil concentration ratios of 226Ra for contrasting sites around an active U mine-mill

International Nuclear Information System (INIS)

Ibrahim, S.A.; Whicker, F.W.

1988-01-01

Concentrations of 226Ra were determined in native vegetation and underlying substrate (soil and tailings) at various sites around a conventional open-pit, acid leach U production operation in Wyoming. Plant/soil concentration ratios (CRs) for 226Ra were estimated for various sites, including weathered tailings; a tailings impoundment shoreline; downwind from exposed tailings; a mine overburden reclamation area; and several background locations. Radium-226 concentrations for vegetation and substrate and CR values from the perturbed sites were elevated above background. The highest vegetation concentration (1.3 Bq g-1) was found in a grass which had invaded exposed, weathered tailings. Levels of 226Ra in soil and vegetation and CR values decreased with distance from the tailings impoundment edge. CR values varied significantly among sites, but few differences were found between plant species groups. The observed CR values ranged from 0.07 at the background and reclamation areas to 0.4 downwind from the tailings area. Average CR values for plants growing on exposed tailings and within one meter from the impoundment edge were 0.15 and 0.3, respectively. CR values of 226Ra for plants on tailings substrates were comparatively low in contrast to other radionuclides in the U chain. We speculate that in the case of sulfuric acid leached tailings-derived material, 226Ra is sequestered as sulfate, which is highly insoluble relative to the sulfates of the other elements (e.g., U and Th) resulting in reduced availability for plant uptake

The concentrations of 226 Ra and 210 Pb in food cultivated in Pocos de Caldas

International Nuclear Information System (INIS)

Hollanda Vasconcellos, L.M. de.

1984-01-01

The aim of this study is to determine the average concentrations of 226 Ra and 210 Pb in vegetables widely cultivated in the region, mainly potatoes, carrots, beans and corn which are the main agricultural products (considering production and human consume) in the region and estimation of the average transfer factors soil-foodstuff for both radionuclides. The total 226 Ra and 210 Pb content in the soil was determined by gamma spectrometry. The exchangeable fraction was obtained by ammonium acetate solution extraction. The 226 Ra was analysed by the classical radon emanation procedure and the 210 Pb was isolated by a radiochemical procedure and determined by radiometry of its daughter 210 Bi beta emissions with a Geiger Mueller counter. (author)

Sequential survey of the occurrence and the possible effects of a 226Ra surplus in harbour slurry polder grounds: Definition study

International Nuclear Information System (INIS)

Stoop, P.; Lembrechts, J.

1993-11-01

Sediments in the harbors of Rotterdam contain relatively large amounts of naturally occurring radionuclides resulting from emissions of the ore-processing industries (88Be, 92Be). Using harbour sludge as a landfill for polders has locally caused the 226 Ra contents of the soil to be a factor of 4 higher than the expected 226 Ra background. In polders where 226 Ra was measured, the 226 Ra surplus was found to be proportional to the cadmium contents (92Mo). Data on cadmium contents are available for many polders and therefore, cadmium may be useful as a tracer for enhanced levels of 226 Ra. Enhanced levels of 226 Ra may cause higher radon concentrations in dwellings that are built on these soils. Therefore, an extensive research programme is started to study the relation between the 226 Ra contents of the soil and radon concentrations in dwellings. The Laboratory of Radiation Research of RIVM has proposed to set up a sub-programme, focusing on the sites where harbour sludges have been dumped, with the following goals: 1) to investigate if there are dwellings with enhanced radon concentrations as a result of a 226 Ra surplus and 2) to investigate if the relation between the 226 Ra-surplus and the cadmium contents found is generally valid and useful. In this report we describe how this sub-programme may be set up and we give specific advice on the answers to various choices. We propose a.o. to use soil samples from 30 polders to investigate the relation between the 226 Ra surplus and the cadmium contents and to study in eight polders the possible consequences of enhanced 226 Ra levels for the radon concentrations in dwellings. Because the radon measurements take one year (four measurements averaged over three month) we propose that simple diagnostic measurements are made simultaneously with the radon measurements. These additional measurements include measurements of the groundwater table and of the effective ventilation pattern in the dwelling. 1 fig., 5 tabs., 16

{sup 226}Ra concentrations in crayfish tissues, water, and sediments from the Serpent River Basin in Northeastern Ontario, Canada

Energy Technology Data Exchange (ETDEWEB)

Alikhan, M.A. [Laurentian Univ., Sudbury, ON (Canada). Dept of Biology

1996-12-31

Lower Serpent River, as well as Elliot, McCarthy and McCabe lakes had highest {sup 226}Ra contamination, Chrisman, Quirke and Whiskey lakes a moderate one, Flack and Semiwhite lakes and the `distant` control, Lake Wanapitei, the lowest. {sup 226}Ra activity in Cambarus robustus tissues was directly related to their background levels. Thus, concentration coefficient (tissue/sediment concentrations) for {sup 226}Ra ranged from 0.53 to 0.74 in highly contaminated Elliot and McCarthy lakes, 0.28 to 0.59 in moderately contaminated Quirke and Whiskey lakes, and from 0.27 to 3.44 in least contaminated Semiwhite and Flack lakes. Among various organs analysed, exoskeleton showed the highest (43.04 - 90.69%) and the tail muscles the lowest (2.95 -17.14%) {sup 226}Ra activity. {sup 226}Ra concentrations in the alimentary canal were considered a part of the ambient environment as they had not been absorbed. 12 refs, 1 fig, 1 tab.

210Pb/226Ra disequilibria in otoliths of blue grenadier, (Macruronus novaezelandiae); problems associated with radiometric aging

International Nuclear Information System (INIS)

Fenton, G.E.; Ritz, D.A.

1990-01-01

Otoliths from blue grenadier (Macruronus novaezelandiae), which had been aged previously by annuli analysis, were analysed for the naturally occurring radionuclides 210 Pb and 226 Ra in an attempt to independently verify their age. It is concluded that the radiometric technique could not be applied to determine age because the results showed that 226 Ra was not incorporated at a constant rate throughout the life of M. novaezelandiae. Uptake of 226 Ra was greater in juveniles than in adult fish. This was probably due to the juvenile phase inhabiting inshore/estuarine waters. 20 refs., 1 tab., 2 figs

The 226 Ra, 210 Pb and essential elements bioavailability to pines at Urgeirica uranium mill tailings

International Nuclear Information System (INIS)

Madruga, M.J.; Faria, I.

2006-01-01

The objective of this study is to correlate the uptake of the natural radionuclides 226 Ra and 210 Pb with the essential elements, potassium, calcium and magnesium in the pines growing at the 'Urgeirica uranium mill tailings. It can be concluded that the potassium, calcium and magnesium mean concentration ratio values are, about two to three orders of magnitude, higher than the values obtained to 226 Ra and 210 Pb for pines growing on the Urgeirica uranium mill tailings. The concentration ratio values higher than 1 obtained to the potassium, calcium and magnesium elements indicate that pines are behaving as accumulators to these elements. Contrarily, the 226 Ra and 210 Pb concentration ratio values lower than 1 indicates that pines are behaving as excluders to these radionuclides. So, it can be concluded that this kind of plants is not suitable to a phyto remediation strategy. In general, a marginally significant correlation was observed between the potassium, calcium and magnesium concentrations, the cation-exchange capacity and the ph in the tailings and the 226 Ra and 210 Pb pines/tailings concentration ratios. (N.C.)

Measurement of 226Ra in water and 222Rn in water and air by liquid scintillation counting

International Nuclear Information System (INIS)

Schoenhofer, F.

1992-01-01

In the Austrian province of Lower Austria a comprehensive programme for measurement of 222 Rn and 226 Ra in drinking water was conducted. A simple liquid scintillation counting (LSC) method was used which gives a LLD of 30 mBq per litre for 226 Ra without any chemical separation. Results are presented and the health significance is discussed. For 222 Rn in air a commercially available simple charcoal system with LSC was used. The system was tested in a house with elevated radon concentration under normal living conditions. During relatively short 2-day periods a maximum deviation of ± 30% from the monthly mean value was found. The advantages of LSC are that the procedures are very simple and cheap. (author)

Report on the intercomparison run IAEA-312 Ra-226, Th and U in soil

International Nuclear Information System (INIS)

Strachnov, V.; Valkovic, V.; Zeisler, R.; Dekner, R.

1991-01-01

This report contains the results of the intercomparison IAEA-312 on the determination of uranium, thorium and Ra-226 in an Indonesian soil sample. The participants included 39 laboratories located in 17 countries, and statistical evaluation of their data yield recommended values for these elements. The elements, their recommended values and confidence intervals are: Ra-226, 269 Bq/kg (250-287); Th, 91.4 microg/g (81.3-101.5); U, 16.5 microg/g (15.7-17.4). Tabs

226Ra activity in the mullet species Liza aurata and South Adriatic sea marine environment of Montenegro

International Nuclear Information System (INIS)

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

2010-01-01

226 Ra activity in the South Adriatic Sea-water, surface sediment, mud with detritus, sea-grass (Posidonia oceanica) samples and the mullet (Mugilidae) species Liza aurata, as well as soil and sand from the Montenegrin Coast-was measured using the six-crystal gamma-coincidence spectrometer PRIPYAT-2M. The results are used for calculation of the absorbed (and annual effective) dose rates in air due to the 226 Ra gamma radiation. The absorbed dose rates ranged from 5.94 to 97.16 nGy h -1 (soil) and from 0.65 to 7.65 nGy h -1 (sand). In seawater 226 Ra activity is found to be from 0.08 to 0.15 Bq l -1 , while in whole L. aurata individuals from 0.58 to 1.97 Bq kg -1 . Annual intake of 226 Ra by human consumers of this fish species has been estimated to provide an effective dose of 0.006 mSv y -1 . (authors)

Elimination of natural uranium and {sup 226}Ra from contaminated waters by rhizofiltration using Helianthus annuus L

Energy Technology Data Exchange (ETDEWEB)

Vera Tome, F. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: fvt@unex.es; Blanco Rodriguez, P. [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain)

2008-04-15

The elimination of natural uranium and {sup 226}Ra from contaminated waters by rhizofiltration was tested using Helianthus annuus L. (sunflower) seedlings growing in a hydroponic medium. Different experiments were designed to determine the optimum age of the seedlings for the remediation process, and also to study the principal way in which the radionuclides are removed from the solution by the sunflower roots. In every trial a precipitate appeared which contained a major fraction of the natural uranium and {sup 226}Ra. The results indicated that the seedlings themselves induced the formation of this precipitate. When four-week-old seedlings were exposed to contaminated water, a period of only 2 days was sufficient to remove the natural uranium and {sup 226}Ra from the solution: about 50% of the natural uranium and 70% of the {sup 226}Ra were fixed in the roots, and essentially the rest was found in the precipitate, with only very small percentages fixed in the shoots and left in solution.

226Ra concentration in the teeth of habitants of areas with high level of natural radioactivity in Ramsar

International Nuclear Information System (INIS)

Aghamiri, S. Mahmoud Reza; Ghorbani, Zahra; Darafsheh, Arash; Torabzadeh, Hasan; Fathivand, Ali Asghar; Minuchehr, Abdulhamid; Jalinoos, Alireza

2006-01-01

The level of natural radiation in some regions of Ramsar, a northern coastal city of Iran, is known to be among the highest levels of natural radiation in the world. 226 Ra existing in high concentrations in the soil of this region is washed by underground water and transferred to the surface. In this way, 226 Ra enters the food chain of residents and substitutes within the hard body tissues of humans. 226 Ra is one of the so-called bone seekers as its metabolic processes in the human body are similar to calcium and remains in hard tissues of body because of its long half-life, and being an α emitter causes dangerous effects on human health. The purpose of this study is to determine the concentration of 226 Ra in the teeth of residents of these high-level natural radiation areas, compared with a control group. Thirteen teeth in five groups were studied as the case group and thirteen teeth in five corresponding control groups were inspected. The mean values of the activity of 226 Ra in the case group and in the control group were 0.32 and 0.18 mBq g -1 , respectively

The Distributions of the Radionuclides Ra-226, Th-232 and K-40 in Various Parts of The Alfalfa Plant

International Nuclear Information System (INIS)

Salahel Din, K.; Harb, S.; Abbady, A.; Saad, N.

2011-01-01

The distribution of naturally occurring Ra-226, Th-232 and K-40 in different part of alfalfa plant from two different soils of Qena (South Valley University and Qena governorate farms) was studied under natural field conditions. Sixty two samples (alfalfa plant and its soil) were taken from nine sites inside farms. The samples were analyzed for their Ra-226, Th-232 and K-40 activity concentrations using gamma ray spectrometer consists of 3 x 3 NaI (Tl). The daily intakes of these radioisotopes by calves, milking cattle and sheep were calculated by multiplying concentrations in alfalfa and the daily consumption rates of these plants.

Development of low level 226Ra analysis for live fish using gamma-ray spectrometry

Science.gov (United States)

Chandani, Z.; Prestwich, W. V.; Byun, S. H.

2017-06-01

A low level 226Ra analysis method for live fish was developed using a 4π NaI(Tl) gamma-ray spectrometer. In order to find out the best algorithm for accomplishing the lowest detection limit, the gamma-ray spectrum from a 226Ra point was collected and nine different methods were attempted for spectral analysis. The lowest detection limit of 0.99 Bq for an hour counting occurred when the spectrum was integrated in the energy region of 50-2520 keV. To extend 226Ra analysis to live fish, a Monte Carlo simulation model with a cylindrical fish in a water container was built using the MCNP code. From simulation results, the spatial distribution of the efficiency and the efficiency correction factor for the live fish model were determined. The MCNP model will be able to be conveniently modified when a different fish or container geometry is employed as fish grow up in real experiments.

Estimative of alpha radiation dose due to natural concentration of Ra-226 in waters from Pocos de Caldas

International Nuclear Information System (INIS)

Sigaud, G.M.

1979-01-01

A dosimetric model for calculating the annual dose equivalent for an individual and the annual collective dose equivalent from 226 Ra is developed. This model is applied to the measured concentrations of 226 Ra in waters of the hydro graphic basins of the Pocos de Caldas plateau, using the pathways of drinking water and ingestion of food grown in irrigated fields. A linear model for simulating potential 226 Ra contamination of the waters of the region is also applied, and the doses from these contaminations are estimated using the dosimetric model developed. (author)

Partitioning and redistribution of exogenous Ra226 in farm soils from the vicinity of the First Brazilian Mine and Mill

International Nuclear Information System (INIS)

Teixeira, V.S.; Franca, E.P.

1988-01-01

A sequential selective extration method was employed to assess the partitioning and redistribution of exogenous 226 Ra into geochemical fractions of farm soils collected around the first Brazilian Uranium Mine and Mill. Six soil samples were contaminated in the laboratory by 226 a solution, simulating an irrigation procedure. After selective extractions, 226 Ra was analysed in six geochemical fractions: soluble (A); exchangeable (E); bound to carbonates (C); reducible (R); oxidizable (O); residual or matricial (M). The same method was also used in these soils before and after cultivation. The exogenous 226 Ra was mainly associated to the (R) and (O) fractions followed by the (E) and (C) ones. Exchangeable 226 Ra (fractions (A) + (E)) represents 21.8%. Statistically significant differences before and after cultivation were obtained only in the fractions (C) and (M). (Author) [pt

Efficiency of Cleanup of Ra-226 Contaminated Gravel Assayed by LSC and TL Dosimetry

International Nuclear Information System (INIS)

Mamoon, A.; Abulfaraj, W.H.; Kamal, S.M.; Sohsah, M.A.

1999-01-01

The present study concerns itself with decontamination of gravel that had been contaminated with Ra-226 from natural origins. Aqueous solutions of different compositions including water, and various concentrations of CaCl 2 and BaCl 2 were used to leach the contaminated gravel. The leaching experiments were carried out in glass columns. In some leaching experiments a sample of a common brand of sandy soil (fine sand with traces of silt )was placed below the gravel to test the binding capacity (sorption) of this soil for the leached Ra-226

Risk assessment of human exposure to Ra-226 in oil produced water from the Bakken Shale.

Science.gov (United States)

Torres, Luisa; Yadav, Om Prakash; Khan, Eakalak

2018-06-01

Unconventional oil production in North Dakota (ND) and other states in the United States uses large amounts of water for hydraulic fracturing to stimulate oil flow. Most of the water used returns to the surface as produced water (PW) containing different constituents. Some of these contents are total dissolved solids and radionuclides. The most predominant radionuclide in PW is radium-226 (Ra-226) of which level depends on several factors including the content of certain cations. A multivariate regression model was developed to predict Ra-226 in PW from the Bakken Shale based on the levels of barium, strontium, and calcium. The simulated Ra-226 activity concentration in PW was 535 pCi/L supporting extremely limited actual data based on three PW samples from the Bakken (527, 816, and 1210 pCi/L). The simulated activity concentration was further analyzed by studying its impact in the event of a PW spill reaching a surface water body that provides drinking water, irrigation water for crops, and recreational fishing. Using food transfer factors found in the literature, the final annual effective dose rate for an adult in ND was estimated. The global average annual effective dose rate via food and drinking water is 0.30 mSv, while the predicted dose rate in this study was 0.49 mSv indicating that there is potential risk to human health in ND due to Ra-226 in PW spills. This predicted dose rate is considered the best case scenario as it is based on the simulated Ra-226 activity concentration in PW of 535 pCi/L which is close to the low end actual activity concentration of 527 pCi/L. Copyright © 2018 Elsevier B.V. All rights reserved.

Dating hapuka otoliths using 210 Pb/226 Ra, with comments on dating orange roughy otoliths

International Nuclear Information System (INIS)

Whitehead, N.E.; Ditchburn, R.G.

1996-01-01

It is shown that Hapuka otoliths cannot be reliably dated using the 210 Pb/ 226 Ra method because contrary to previous assumptions, excess 210 Pb is incorporated into the outer layers of otoliths which have been taken from old fish, though the 226 Ra incorporation remains normal. This is shown to apply also to Orange Roughy otoliths. Ages based on calculations using previously published methods will be artificially old. (author). 13 refs., 2 tabs., 3 figs

Distribution of 226Ra, 232Th and 40K in soils and sugar cane crops at Corumbatai river basin, Sao Paulo State, Brazil

International Nuclear Information System (INIS)

Tomazini da Conceicao, Fabiano; Bonotto, Daniel Marcos; Jimenez-Rueda, Jairo Roberto; Frutuoso Roveda, Jose Arnaldo

2009-01-01

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 Corumbatai river basin, Sao 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.

Macrodistribution of 226Ra in the human skeleton as determined in vitro by gamma-ray spectrometry

International Nuclear Information System (INIS)

Essling, M.A.; Huff, D.R.

1976-01-01

A large number of γ-ray measurements of 226 Ra in human bone has been made both at MIT and CHR-ANL. These data are analyzed for correlations of the specific activity ratio of a bone group with other parameters, an interlaboratory comparison of the measurements, and an estimate of the errors expected when a whole-body content is calculated from the 226 Ra determination on a partial skeleton

Report on the intercomparison run IAEA-313 Ra-226, Th and U in stream sediment

International Nuclear Information System (INIS)

Strachnov, V.; Valkovic, V.; Zeisler, R.; Dekner, R.

1991-01-01

This report contains the results of the intercomparison IAEA-313 on the determination of uranium, thorium and Ra-226 in two stream sediments from Indonesia. The participants included 36 laboratories located in 18 countries, and statistical evaluation of their data yield recommended values for these elements. The elements, their recommended values and confidence intervals are: Ra-226, 343 Bq/kg (307-379); Th, 77.1 microg/g (74.8-79.4); U, 18.2 microg/g (17.0-19.3). Tabs

Transfer of 226Ra, 85Sr and 137Cs from milk to milk products

International Nuclear Information System (INIS)

Al-Masri, M.S.; Nashawati, A.; Amin, Y.; Al-Akel, B.

2006-01-01

Transfer of 226 Ra, 85 Sr and 137 Cs from cow and sheep milk to various Syrian dairy products has been evaluated. Dairy products include Kashkivan cheese, braided cheese, Haloom cheese, Sircassian cheese, liquid cheese, native cheese, cottage, thick yogurt, butter and milk cream. The results showed that the percentage of 226 Ra, 85 Sr and 137 Cs transferred from cow milk to milk cream (P t = food processing retention factor x processing efficiency x 100%) has reached 32%, 16% and 7%, respectively. Butter and liquid cheese were found to have the lowest percentage of transferred 226 Ra, 85 Sr and 137 Cs. Most of the obtained P t values of the studied radionuclides in thick yogurt were relatively low in spite of the high processing efficiencies of thick yogurt. Moreover, the transfer, P t , of the studied radionuclides from cow milk to the prepared cheese was higher than those values determined for sheep milk. This is due to differences in chemical compositions of each type of milk. On the other hand, the treatment of Native cheese, most commonly consumed cheese in Syria, with different concentrations of NaCl solutions showed that 137 Cs was completely removed from cheese soaking in 5% NaCl solution (soaking time of 48 hours), while 40% of 226 Ra and 80% of 85 Sr were also decontaminated using 0-2.5% NaCl solutions and soaking time of 48 hours. Based on the obtained results, industrialization processes of the dairy products that resulted the removal of radionuclides have been identified. (author)

Uptake and kinetics of 226Ra, 210Pb and 210Po in big sagebrush

International Nuclear Information System (INIS)

Simon, S.L.

1985-01-01

Root uptake of 226 Ra, 210 Pb and 210 Po by mature sagebrush was studied using a soil injection method for spiking the soil with minimal root disturbance. The main objective was to measure vegetation concentrations and determine concentration ratios (CR's) due to root uptake as a function of time in mature big sagebrush. Concentration ratios obtained in mature vegetation and in steady-state situations may be valuable in assessing the impact of uranium mining and milling. The vegetation was sampled approximately every 3 months for a 2 year period. Significant levels of activity were detected in the vegetation beginning at the first sampling (81 days after soil injection for 226 Ra, 28 days for 210 Pb and 210 Po). There was an exponential decrease in concentration to an apparent steady-state value. Mean values (geometric) of the data pooled over the second year period indicated that the steady-state CR's for 226 Ra, 210 Pb and 210 Po, as determined in mature sagebrush, were 0.04, 0.009, and 0.08, respectively. A three compartment mathematical model was formulated to help understand mechanisms of plant uptake and to predict, if possible, the concentration of 226 Ra, 210 Pb and 210 Po in vegetation as a function of time after soil spiking. A numerical solution was determined by 'calibrating' the general model solution with constants determined from regressions of concentrations in vegetation, soil leaching and leaf leaching data. Validation of the model is currently not possible because of an absence of similar time-dependent uptake studies. 168 refs., 19 figs., 18 tabs

Evaluation of the activity concentration of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb in sediments from Antarctica in the Admiralty Bay region

Energy Technology Data Exchange (ETDEWEB)

Mora, Tamires de A.; Oliveira, Joselene de, E-mail: tamires.mora@usp.br, E-mail: jolivei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Figueira, Rubens C.L.; Mahiques, Michel M.; Sousa, Silvia H.M., E-mail: rfigueira@usp.br, E-mail: mahiques@usp.br, E-mail: smsousa@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto Oceanografico

2015-07-01

In this study, we performed the radiochemical characterization of a sedimentary record (1B profile), collected in the vicinity of Admiralty Bay, King George Island in Antarctic Operation XXXI (January/2013). The activities of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb were determined by the counting of gross alpha and gross beta activities in the precipitates of Ba(Ra)SO{sub 4} and PbCrO{sub 4}. Those measurements were carried out in a low background gas flow proportional detector. The {sup 226}Ra and {sup 228}Ra were measured after 21 days of the final precipitation. The {sup 210}Pb activity was determined after 10 days of the precipitation date by gross beta counting of its {sup 210}Bi decay product. The activity concentration of {sup 226}Ra ranged from 11±1 (mBq g-1) to 54±3 (mBq g{sup -1}), and the {sup 228}Ra ranged from 48±5 (mBq g{sup -1}) to 155±16 (mBq g{sup -1}). The activity concentration of {sup 210}Pb varied from 8±1 (mBq g{sup -1}) to 458±46 (mBq g{sup -1}), while unsupported {sup 210}Pb ranged from 6±1 (mBq g{sup -1}) to 434±65 (mBq g{sup -1}). The {sup 210}Pb concentrations in sediments have often been used to dating events like deposition and accumulation in various marine environments. Taking into account the results of {sup 210}Pb and {sup 226}Ra activities obtained in testimony-1B it was estimated the unsupported {sup 210}Pb activity which was applied to the CIC geochronological dating model (Constant Initial Concentration). Based in these data, the sedimentation rate obtained was 0.63±0.02 cm year{sup -1}. (author)

Viimsi water treatment plant for Ra removal: NORM residue/waste generation, radiation safety issues, and regulatory response

Energy Technology Data Exchange (ETDEWEB)

Kiisk, M.; Suursoo, S.; Realo, E.; Jantsikene, A.; Lumiste, L.; Vaeaer, K.; Isakar, K.; Koch, R. [University of Tartu (Estonia)

2014-07-01

In early 2012, the first large-scale water treatment plant, specifically designed to remove Ra-isotopes from groundwater, was commissioned in Viimsi parish, North-Estonia. The plant serves approximately 15 000 consumers with maximum production capacity of 6000 m{sup 3}/d. The chosen water treatment technology is chemical free and is based on co-precipitation and adsorption with Fe(OH){sub 3} and MnO{sub 2} flocks, and adsorption of residual Ra onto zeolite sand. The chosen technology is a complex approach and is designed to reduce high Fe and Mn concentrations as well as dissolved gases along with Ra isotopes. It is proved to be well adapted with hydro-chemical conditions of the groundwater feeding the plant. As the novel technology has been applied for the first time on a large scale, the plant was taken under long-term investigation when commissioned. The latter focuses on three areas: Ra removal efficiency and its dynamics, build-up of radioactive waste, and radiation safety. The average Ra-226 and Ra-228 activity concentrations in raw water feeding the plant are approximately 0.5 Bq/L and 0.6 Bq/L, respectively, resulting in total indicative dose of 0.4 mSv/y. Operating conditions of the plant are restricted by the established indicative value of 0.1 mSv/y for drinking water, i.e. a minimum 75% removal efficiency for Ra is required. Results of the studies show that the plant operates at Ra-removal efficiency of 98% or higher without the need of regeneration or replacement of filtering materials within the first two years. Measurements confirm that ∼90% of Ra accumulates in the solid filter media, 8-9% is washed out by backwash system as liquid effluent and 1-2% is fed on to the consumer distribution network. It has been calculated that at the level of current production capacity (below 3000 m{sup 3}/d) the yearly accumulation rate in the plant is approximately 300 and 400 MBq/y for Ra-226 and Ra-228, respectively. These values strongly exceed the exemption

Inventory of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb in marine sediments cores of Southwest Atlantic Ocean

Energy Technology Data Exchange (ETDEWEB)

Costa, Alice M.R.; Oliveira, Joselene de, E-mail: alice.costa@usp.br, E-mail: jolivei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Gerencia de Metrologia das Radiacoes. Lab. de Radiometria Ambiental; Figueira, Rubens C.L.; Mahiques, Michel M.; Sousa, Silvia H.M., E-mail: rfigueira@usp.br, E-mail: mahiques@usp.br, E-mail: smsousa@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto Oceanografico

2015-07-01

{sup 210}Pb (22.3 y) is a radioactive isotope successfully applied as tracer of sediment dating of the last 100-150 years. The application of {sup 226}Ra and {sup 228}Ra as paleoceanographic tracers (half-lives of 1,600 y and 5.7 y, respectively) also gives some information of ocean's role in past climate change. In this work, it was analyzed 2 sediment cores collect at Southwest Atlantic Ocean. The sediments samples were freeze-dried and acid digested in microwave. It was carried out a radiochemical separation of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb and performed a gross alpha and gross beta measurement of both precipitates Ba(Ra)SO{sub 4} and PbCrO{sub 4} in a low background gas-flow proportional counter. Activity concentrations of {sup 226}Ra ranged from 45 Bq kg{sup -1} to 70 Bq kg{sup -1} in NAP-62 and from 57 Bq kg{sup -1} to 82 Bq kg{sup -1} in NAP-63 samples. The concentration of {sup 228}Ra varied between 37 Bq kg{sup -1} and 150 Bq kg{sup -1} in NAP-62 and between 23 Bq kg{sup -1} and 111 Bq kg{sup -1} in NAP-63 samples. The concentration of total {sup 210}Pb ranged from 126 Bq kg{sup -1} to 256 Bq kg{sup -1} in NAP-62 and from 63 Bq kg{sup -1} to 945 Bq kg{sup -1} in NAP-63 samples. Results of {sup 210}Pb{sub uns} varied from 68 Bq kg{sup -1} to 192 Bq kg{sup -1} for NAP-62, while varied from <4.9 Bq kg{sup -1} to 870 Bq kg{sup -1} in NAP-63 profile. Increased values of {sup 210}Pb{sub uns} were found on the top of both NAP-62 and NAP- 63 sediment profile. (author)

Evaluation of the received dose by the Ra-226 incorporation due to the consumption of ground waters in Cuba

International Nuclear Information System (INIS)

Zerquera, T.J.; Prendes A, M.

1996-01-01

Due to the good solubility of radium compounds in the earth core, concentrations of Ra-226 in ground water may be significant. Some countries, like France and Finland, have reported Ra-226 concentrations in ground water up to 2700 and 5300 mBq/L, respectively. Due to to these reasons, the control of the concentrations of Ra-226 in water for human consumption became a practice in various countries. Sampling and analysis of Ra-226 in water from the principal springs and sources in Cuba have been organized since 1992, taking into account the volumes and primary features of each source. Radium-226 concentrations in analyzed waters are in the range of 26-144 mBq/L. These concentrations correspond to values reported in the literature for sources in other countries. Committed dose for water consumption in a year are in the order of nano Sievert. Determined concentrations are below the values established by corresponding Cuban Standard and no restriction have been recommended. (authors). 5 refs., 2 figs

Leachability of 226Ra from spiked soil as a function of time

International Nuclear Information System (INIS)

Deming, E.J.

1983-01-01

The bioavailability of 226 Ra for plant uptake may be dependent on its solubility from the soil components. Solubility of radium from soil may change with time due to chemical and physical binding. A laboratory study was designed to provide data on the water leachable fraction of 226 Ra from spiked soil as a function of time. A decreasing trend in the percent leachable fraction was observed over time. The data was modeled by non-linear regression to be a decreasing exponential to a constant value. This information may be helpful in providing an understanding of a similar trend observed in plant uptake studies. The value for the available amount of radium determined in this investigation may help to provide a more meaningful measurement of concentration ratios in plants. 22 references, 3 figures, 5 tables

Biomass selection for biosorption study of 226 Ra and 137 Cd radionuclides

International Nuclear Information System (INIS)

Costa, Wilson Cervi da

2003-01-01

The main goal of this work was to verify the potentialities to apply the biosorption technique to synthetic and real solution containing 226 Ra and 137 Cs, utilizing the seaweed Sargassum sp. and the microorganisms Penicillium sp., Saccharomyces cerevisiae and Monoraphidium sp. Indeed, the screening of the most effective biomass to remove the radionuclides was also a central objective. 226 Ra was selected due to its high radiotoxicity and the fact that it can be assimilated and incorporated by living organism through substitution og Mg 2+ and Ca 2+ , two essential nutrients. On the other hand, the selection of 137 Cs, a radionuclide of medium toxicity, was due to its mobility in the environment, which increases the possibility to be assimilated by the organisms as the essential nutrients Na + and K + . (author)

Estimation of radionuclide concentration of 238U, 226Ra, 232Th in air in Wuhan city

International Nuclear Information System (INIS)

Shi Jinhua; Chen Changhua

1989-01-01

The concentrations of 238 U, 226 Ra and 232 Th in air in Wuhan area were estimated by assuming that they originate from resuspended particles of soil and investigating the dust content in air and the concentrations of these radionuclides in soil. 60 soil samples were collected from April to October, 1984, and 7346 air dust samples during 1981-1985. The estimated mean air concentrations of 238 U, 226 Ra and 232 Th were 24.0 x 10 -9 , 18.9 x 10 -9 and 28.7 x 10 -9 , Bq/L, respectively. Their highest values were observed of 30.4 x 10 -9 , 23.9 x 10 -9 and 36.2 x 10 -9 Bq/L in 1983. Seasonal change of the concentrations was clear as shown in the data of 1984 and 1985, which was related to the meterological conditions. Among the 6 districts of Wuhan city, the highest concentration was in Qingshan and the lowest in Wuchang

Measurement of the E1/E3 phase in 226Ra

Science.gov (United States)

Amzal, N.; Butler, P. A.; Hawcroft, D.; Hammond, N. J.; Herzberg, R.-D.; Jones, G. D.; Scholey, C.; Stezowski, O.; Czosnyka, T.; Iwanicki, J.; Napiorkowski, P. J.; Julin, R.; Mach, H.; Cerderka¨Ll, J.; Fraile, L. M.; Fynbo, H. O. U.; Isolde Collaboration

2004-04-01

We report experimental attempts to determine the sign of the electric dipole moment (relative to the electric octupole moment) in the octupole deformed nucleus 226Ra. Sensitivity to this quantity is observed in the measured yields of γ-ray transitions following very low energy Coulomb excitation.

Concentration factors of 226 Ra in the mullet species Liza aurata

International Nuclear Information System (INIS)

Antovic, I.; Antovic, N.M.

2011-01-01

On the basis of measured 226 Ra activity concentrations in whole individuals of the mullet species Liza aurata, its muscles and skeleton, concentration factors for transfer of radium from water and sediment to this mullet species from the South Adriatic Sea, have been determined. (author) [sr

Distribution of Pa-231 and Ra-226 in rock. An indicator of rock matrix diffusion

International Nuclear Information System (INIS)

Saarinen, L.; Suksi, J.

1995-01-01

Distribution of Ra-226 and Pa-231 in rock has been studied to find signatures that may be attributed to diffusion. The idea of studying these nuclides originated from the need to obtain interpretative support to the findings of U movement in rock. Concentration profiles of Ra-226 and Pa-231 with other U series nuclides were measured across the secondary U accumulations observed in altered rock close to a fracture in the vicinity of U deposit, and in a radioactivity anomaly. (27 refs., 10 figs., 2 tabs.)

Determination of 226Ra and 228Ra concentrations in foodstuffs consumed by inhabitants of Tehran city of Iran

International Nuclear Information System (INIS)

Asefi, M.; Fathivand, A. A.; Amidi, A.; Najafi, A.

2005-01-01

The presence of primordial radionuclide in human habitats has always been a source of prolonged exposure. Measurement of naturally occurring radionuclides in the environment can be used as baseline to evaluate the impact of non-nuclear activities and also routine releases from nuclear installations. Materials and Methods: A total of 56 samples from 18 different foodstuff including root vegetables (beetroot, carrot, onion, potato, radish and turnip), leafy vegetables (lettuce, parsley, spinach and white cabbage) and lentil, kidney bean, Soya, eggs, rice, meat, tomato and cooking oil were purchased and analyzed by low level gamma spectrometry. Results: The 226 Ra concentrations from root vegetables varied from 13-62 mBqkg -1 with turnip of highest concentration, i.e. 62mBqkg -1 . Among leafy vegetables; parsley showed the maximum concentration of 228 Ra equal to 173 mBqkg -1 . 226 Rand 228 Ra contents in the soya, 394 and 578 mBq kg -1 was much higher than those of other samples respectively. Conclusion : Results indicate that foodstuff consumed by Tehran inhabitants have low radium content and are safe, as far as radium concentrations is concerned

Evaluation of the activity concentration of 226Ra, 228Ra and 210Pb in sediments from Antarctica in the Admiralty bay region

International Nuclear Information System (INIS)

Mora, Tamires de Araujo

2015-01-01

The natural radionuclides from radioactive series of 238 U, 235 U and 232 Th have been applied as tracers in environmental studies for understanding the dynamics that occur in both marine and terrestrial environment, as for example, in research of oceanic processes and management of the coastal region. In the marine environment, these radionuclides can be used to estimate biogeochemical fluxes of marine particles and nutrients that occur in the water column as well as in the sediment. Several research works applied the distribution and the respective disequilibrium degree of natural radionuclides in the environment, including geochronological models for obtaining historical information on samples of certain sediment profile. In this study we performed a radiochemical characterization of the distribution of 226 Ra, 228 Ra and 210 Pb from a sedimentary column called 1B (248 cm long) collected in the Admiralty Bay, Antarctic Peninsula region. The methodology used included the acid leaching of sediment samples followed by the radiochemical sequential separation of 226 Ra and 228 Ra by co-precipitation with Ba(Ra)SO 4 and 210 Pb by co-precipitation with PbCrO 4 . All measurements were carried out by counting of gross alpha and gross beta measures in a low background gas flow proportional detector. The activity concentrations of 226 Ra and 210 Pb were used to estimate the unsupported 210 Pb activities present in sediment profile 1 B. Based on unsupported 210 Pb data and the application of the CIC model (Constant Initial Concentration), it was possible to determine the sedimentation rate of 0.59 ± 0.05 cm /year. (author)

226Ra, 210Pb and 210Po disequilibria in the western North Pacific

International Nuclear Information System (INIS)

Nozaki, Y.; Isunogai, S.

1976-01-01

226 Ra, 210 Pb and 210 Po were measured in oceanic profiles at two stations near the Bonin and Kurile trenches. 210 Po is depleted by 50% on average relative to 210 Pb in the surface water. In the deep water, 210 Pb is about 25% deficient relative to 226 Ra. Based on the deficiency, 210 Pb residence time with respect to removal by particulate matter was estimated to be less than 96 years in the deep water. 210 Pb deficiency in the bottom water was significantly greater than that of the adjacent deep water, indicating more effective removal near or at the bottom interface. 210 Pb, 210 Po and Th appear to have similar overall rate constants of particulate removal throughout the water column. (Auth.)

Uptake and kinetics of 226Ra, 210Pb and 210Po in big sage brush

International Nuclear Information System (INIS)

Simon, S.L.

1985-01-01

Root uptake of 226 Pb and 210 Po by mature sage brush was studied using a soil injection method for spiking the soil with minimal root disturbance. The main objective was to measure vegetation concentrations and determine concentration ratios (CR's) due to root uptake as a function of time in mature big sage brush. Concentration ratios obtained in mature vegetation and in steady-state situations may be valuable in assessing the impact of uranium mining and milling. The vegetation was sampled approximately every 3 mo for A 2 y period. Significant levels of activity were detected in the vegetation beginning at the first sampling (81 d after soil injection for 226 Ra, 28 d for 210 Pb and 210 Po). There was an exponential decrease in concentration to an apparent steady state value. Mean values (geometric) of the data pooled over the second year period indicated that steady-state Cr's for 226 Ra, 210 Pb and 210 Po, as determined in mature sage brush, were 0.04, 0.009, and 0.08, respectively. Investigations were also carried out to verify the suitability of soil injection for uptake studies and to evaluate the time dependence of 226 Ra leaching from sage brush leaves. The soil injection method was determined to produce, on the average, uptake equivalent to that produce by a uniform soil distribution, however, the variety of uptake for plants growing in injected soil was higher than for plants growing in uniformly contaminated soil. A three compartment mathematical model was formulated to help understand mechanisms of plant uptake and to predict, if possible, the concentration of 226 Ra, 210 Po in vegetation as a function of time after soil spiking

Activity concentrations of /sup 226/Ra, /sup 228/Ra, /sup 210/Pb, /sup 40/K and /sup 7/Be and their temporal variations in surface air

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, H.; Winkler, R.

1987-01-01

Activity concentrations of the long-lived natural radionuclides /sup 226/Ra, /sup 228/Ra, /sup 210/Pb, /sup 40/K and of /sup 7/Be in surface air were measured twice monthly at a semi-rural location 10 km north of Munich (FRG) for at least three years. For the time interval 1983-1985, all values were found to be distributed log-normally, with geometric means (in ..mu..Bq m-./sup 3/) of 1.2 for /sup 226/Ra, 0.5 for /sup 228/Ra, 580 for /sup 210/Pb, 12 for /sup 40/K and 3500 for /sup 7/Be. Reflecting their common origin, the activity concentrations of /sup 226/Ra and /sup 40/K are correlated with surface air dust concentrations (geometric mean 59 ..mu..g m/sup -3/). Seasonal variations of /sup 210/Pb and /sup 7/Be air activity concentrations are established for the time interval 1978-1985.. The contribution of local soil activity to the air activity concentrations of these radionuclides and of natural uranium is discussed. Resuspension factors are found to be of the order of 10/sup -9/ m/sup -1/.

Evaluation of the activity concentration of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb in sediments from Antarctica in the Admiralty bay region; Avaliacao da concentracao de atividade de Ra-226, Ra-228 e Pb-210 em sedimentos provenientes da Antartica na regiao da baia do Almirantado

Energy Technology Data Exchange (ETDEWEB)

Mora, Tamires de Araujo

2015-07-01

The natural radionuclides from radioactive series of {sup 238}U, {sup 235}U and {sup 232}Th have been applied as tracers in environmental studies for understanding the dynamics that occur in both marine and terrestrial environment, as for example, in research of oceanic processes and management of the coastal region. In the marine environment, these radionuclides can be used to estimate biogeochemical fluxes of marine particles and nutrients that occur in the water column as well as in the sediment. Several research works applied the distribution and the respective disequilibrium degree of natural radionuclides in the environment, including geochronological models for obtaining historical information on samples of certain sediment profile. In this study we performed a radiochemical characterization of the distribution of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb from a sedimentary column called 1B (248 cm long) collected in the Admiralty Bay, Antarctic Peninsula region. The methodology used included the acid leaching of sediment samples followed by the radiochemical sequential separation of {sup 226}Ra and {sup 228}Ra by co-precipitation with Ba(Ra)SO{sub 4} and {sup 210}Pb by co-precipitation with PbCrO{sub 4}. All measurements were carried out by counting of gross alpha and gross beta measures in a low background gas flow proportional detector. The activity concentrations of {sup 226}Ra and {sup 210}Pb were used to estimate the unsupported {sup 210}Pb activities present in sediment profile 1 B. Based on unsupported {sup 210}Pb data and the application of the CIC model (Constant Initial Concentration), it was possible to determine the sedimentation rate of 0.59 ± 0.05 cm /year. (author)

Radioactive Contamination of Alluvial Soils in the Taiga Landscapes of Yakutia with 137Cs, 226Ra, and 238U

Science.gov (United States)

Chevychelov, A. P.; Sobakin, P. I.

2017-12-01

The concentrations and distribution of 137Cs in alluvial soils (Fluvisols) of the upper and middle reaches of the Markha River in the northwest of Yakutia and 226Ra and 238U in alluvial soils within the El'kon uranium ore deposit in the south of Yakutia have been studied. It is shown that the migration of radiocesium in the permafrost-affected soils of Yakutia owing to alluviation processes extends to more than 600 km from the source of the radioactive contamination. The migration of 137Cs with water flows is accompanied by its deposition in the buried horizons of alluvial soils during extremely high floods caused by ice jams. In the technogenic landscapes of southern Yakutia, active water migration of 238U and 226Ra from radioactive dump rocks. The leaching of 238U with surface waters from the rocks is more intense than the leaching of 226Ra. The vertical distribution patterns of 238U and 226Ra in the profiles of alluvial soils are complex. Uranium tends to accumulate in the surface humus horizon and in the buried soil horizons, whereas radium does not display any definite regularities of its distribution in the soil profiles. At present, the migration of 238U and 226Ra with river water and their accumulation in the alluvial soils extend to about 30 km from the source.

Activity concentrations of 226Ra, 232Th and 40K in brands of fertilisers used in Nigeria

International Nuclear Information System (INIS)

Jibiri, N. N.; Fasae, K. P.

2012-01-01

The activity concentration of naturally occurring radionuclides 40 K, 226 Ra and 232 Th have been measured in different brands of fertiliser samples sold to farmers in retail markets in six commercial cities in southwestern Nigeria. Gamma ray spectroscopy was employed in the measurements of these radionuclides. The results of measurements showed that the average activity concentration of 40 K in the nitrogen, phosphorus and potassium fertilisers across the cities varied from 3972.0 ±416.9 to 5089.3 ±111.3 Bq kg -1 , 9.9 ±7.3 to 450.6 ±14.3 Bq kg -1 for 226 Ra, while for 232 Th it varied from less than lower limit of detection to 15.1 ±2.8 Bq kg -1 . The activity concentrations of 40 K, 226 Ra and 232 Th in single super phosphate (SSP) fertilisers and phosphate rocks were also determined. However, high activity concentrations of 226 Ra were obtained in the SSP fertiliser and phosphate rocks and in particular, two brands of fertilisers from ITL/TAK and F and C companies. The values of the activity concentration of the radionuclides in the brands of fertilisers used in Nigeria are within the range of values reported in several other countries except 40 K. (authors)

Analysis of 226Ra, 232Th 40К and 137Cs in samples of soil from some areas of Republic of Macedonia by using gamma spectrometry

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Todorovik Aleksandra

2012-01-01

Full Text Available Taking into consideration the importance of the distribution and transfer of radio nuclides in soil, an attempt was made in this work to determine the concentration of 226Ra, 232Th 40К and 137Cs in the same. The concentrations of activity in the gamma-absorbed dose rates of the terrestrial naturally occurring radio nuclides, as follows, 226Ra, 232Th and 40K were determined in samples of soil collected from some parts of Republic of Macedonia, i.e. from three major cities in the Republic of Macedonia. The samples are taken by means of a special dosage dispenser which enables sampling of samples at a depth of 0-5 cm, 5-10cm and 10-15cm, thus disabling the sampling above these layers of soil. An identification of radio nuclides and assessment of their activity has been performed by applying gamma spectrometry. The time of counting for each sample was 65000 s. in order to obtain statistically small mistake. The spectrums were analyzed by a commercially available software GENIE-2000 received from Canberra, Austria. The activity of soil had wide range of values: 20.3 to 82.9 Bq kg-1for 226Ra, 16.1 to 82.5 Bq kg-1 for 232Th, 325 to 799.0 Bq kg-1for 40К and 9.1 to 24.3 Bq kg-1for 137Cs, respectively. The concentrations of these radio nuclides have been compared with the available data from the other countries. Natural environmental radioactivity and the associated external exposure due to gamma radiation depend primarily on the geological and geographical conditions. Namely, the specific levels of terrestrial environmental radiation are related to the type of rocks from which the soils originate. The obtained data indicate that the average value of activity of 232Th is about higher than the one of 226Ra The concentration of activity of 40К in the soil has greater value than 32Th and 226Ra in all soils. The causes for the existence of 137Cs in these soils are the nuclear explosions, waste radioactive materials and other incidents. It reaches the

Measurements of 222Rn and 226Ra Levels in environmental samples by using liquid scintillation counter

International Nuclear Information System (INIS)

Moustafa, A.S.

2004-01-01

The advantageous of liquid scintillation counting technique for 6 Ra determination compared with other methods are the high counting efficiency and the easier sample preparation, with no need for sample pre-concentration. In this work, liquid scintillation counting system was used to measure 222 Rn and 226 Ra levels in environmental samples. The liquid scintillation cocktail was prepared in the laboratory and was found efficient for measuring 222 Rn. Soil, sediment and TENORM samples were dried, grind, sieved and added to hydrochloric acid, in a standard scintillation vial, preloaded with the liquid scintillation cocktail. By measuring 222 Rn levels in the prepared vials, at different intervals of time after preparation, 222 Rn and 226 Ra levels were determined

Study of natural radionuclides - "2"2"6Ra, "2"2"8Ra and "2"1"0PB - in marine sediment cores from Southwest Atlantic during the Holocene

International Nuclear Information System (INIS)

Costa, Alice Miranda Ribeiro

2016-01-01

Natural radionuclides from "2"3"8U and "2"3"2Th series have been successfully applied as tracers of environmental process and climate changes. The "2"1"0Pb (half-life of 22.2 years) is used in the geochronological dating technique of sediment cores of the last 100-150 years, and its respective sedimentation rate determination. The study of "2"2"6Ra and "2"2"8Ra concentrations (half-lives of 1,600 years and 5.75 years, respectively) helps calculate the activity of "2"1"0Pb in excess in the environment, besides being important tracers of marine processes, as ground water discharge. In this work it was determined the activity concentrations of "2"2"6Ra, "2"2"8Ra and "2"1"0Pb in four short marine cores collected since the continental platform to upper slope of Southwest Atlantic Ocean. Taking into account the results obtained, sedimentation rates and the ages of each sediment layer were determined using the geochronological dating method with "2"1"0Pb. All sediment samples were total acid digested in microwave. The sequential radiochemical separation of "2"2"6Ra, "2"2"8Ra, "2"1"0Pb were performed, obtaining in the end the precipitation of Ba(Ra)SO_4 and PbCrO_4. The gross α measurements of "2"2"6Ra and gross β measurements of "2"2"8Ra and "2"1"0Pb from the precipitates were carried out in a gas-flow low background proportional counter. Concerning all cores analyzed, the activities concentrations of "2"2"6Ra ranged from 14 Bq.kg"-"1 to 154 Bq.kg"-"1; the concentrations of "2"2"8Ra ranged from 17 Bq.kg"-"1 to 45 Bq.kg"-"1; and the concentrations of "2"1"0Pb ranged from 20 Bq.kg"-"1 to 2,073 Bq.kg"-"1. High values of "2"1"0Pb were observed on the top of all the cores studied, mainly related to atmospheric deposition. The results obtained in this work were of the same order of magnitude of those reported in the literature available on non contaminated areas of Southeast Brazilian Coast. Sedimentation rates fall with the increase of water column depth and ranged from 0

Effect of bedside shielding on air-kerma rates around gynecologic intracavitary brachytherapy patients containing 226Ra or 137Cs

International Nuclear Information System (INIS)

Papin, P.J.; Ramsey, M.J.; LaFontaine, R.L.; LePage, R.P.

1990-01-01

An anthropomorphic phantom was implanted with 226Ra or 137Cs gynecologic intracavitary brachytherapy sources. Air-kerma rate measurements were taken at 10-cm increments along a horizontal plane from the side of the bed at 50 cm, 87 cm, and 136 cm heights above the floor. Five portable lead shields were placed at the head, at the foot and along one side of the bed and readings were taken again at the corresponding heights above, below and behind the shields. The readings were normalized to 100-mg Ra equivalence, and air-kerma rate curves were drawn allowing for the comparison of 226Ra and 137Cs with and without lead shields. The data demonstrated that the air-kerma rates for 137Cs were reduced more than those for 226Ra with the use of the portable lead shields. There was four times the transmission with 226Ra than with 137Cs. The optimal placement was with the lateral bedside shields proximal to the head and foot closest to the bed, with the middle shield overlapping in back. The shields at the head and foot should extend out and overlap the bedside shields. The level of the sources should be positioned near the bottom of the shields. This information will provide the medical health physicist with an estimate of air-kerma rates for both 226Ra and 137Cs with and without shielding for evaluating personnel exposures as well as the effectiveness of current shielding in relation to radiation protection requirements in adjacent rooms or hallways

Measurement of "2"2"6Ra and "2"2"8Ra in Brazilian and Israeli Phosphates

International Nuclear Information System (INIS)

Ferreira, W.; Canella Avelar, A.; Menezes, M.

2014-01-01

Since the 1970s, the IAEA recognizes that phosphoric acid presents an alternate source of uranium, but given the status of both phosphate and uranium markets the potential of recovering uranium from phosphoric acid still marginal. New technologies for the recovery of uranium from phosphoric acid, national and global interests and environment barriers could shape this market in the medium and long-term scenarios. On the other hand, the use of phosphates is the major source of phosphorus in agriculture and livestock. Beyond phosphorus and calcium, phosphate is also source of some hazardous elements, such: arsenic, cadmium, thorium and uranium, including a variety of radioisotopes as well. This radioactivity is sure to be released in the environment, contributing to the background. The risk is not recognized for some of the players in this market, mainly workers who apply phosphate fertilizers in the farmland, in some cases manipulating phosphates with their bare hands, and without any respiratory protection equipment (RPE) as well. This paper deals with the radioactivity from "2"2"6Ra and "2"2"8Ra in four phosphates often used in Brazilian agriculture. Three Brazilian and an Israeli phosphate were analysed and compared with international criteria. The specific activities of "2"2"6Ra (from the uranium decay series) and "2"2"8Ra (from the thorium decay series) were taken into consideration to ensure an adequate risk assessment. Specific activities were determined by high-resolution gamma spectroscopy with germanium detector and Genie® software from Canberra in the Centre of Nuclear Technology Development (CDTN/CNEN). The concentration of "2"2"6Ra was measured using the 186.2 keV energy peak, the concentration of "2"2"8Ra through "2"2"8Ac. The system was calibrated using a set of standard materials from IAEA. The measured samples were crushed and sieved to a grain (98% at least) size as small as 75 μm. Stable mass was achieved grinding, drying at 105°C and mixing

Comparison of 226Ra nuclide from soil by three woody species Betula pendula, Sambucus nigra and Alnus glutinosa during the vegetation period

International Nuclear Information System (INIS)

Soudek, Petr; Petrova, Sarka; Benesova, Dagmar; Tykva, Richard; Vankova, Radomira; Vanek, Tomas

2007-01-01

The uptake of 226 Ra from the contaminated soil was compared in three woody species: alder (Alnus glutinosa), birch (Betula pendula) and elder (Sambucus nigra). The 226 Ra activities increased during the vegetation periods (in 2003, 2004 and 2005) both in the leaves and flowers + seeds. The highest accumulation was found in birch, reaching 0.41 Bq/g DW in the leaves (at the end of the vegetation period in 2003). The lowest 226 Ra accumulation was determined in alder. The extent of 226 Ra accumulation in the leaves of woody species demonstrates that these pioneer woody species can be used as remediation alternative to the use of herbs, provided that the removal of fallen leaves could be achieved in the end of vegetation period

226Ra-210Pb-210Po Levels in Marine Biota and Surface Coastal Sediments from the Red Sea, Sudan

International Nuclear Information System (INIS)

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

2003-01-01

This paper presents data on 226 Ra, 210 Pb and 210 Po activity concentration levels in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (Flamingo bay) of Port sudan harbour. The analyses were performed adopting a simple time efficient method combining alpha-spectrometry, liquid scintillation and Cerenkov counting technique. Generally speaking, surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported from different coastal areas around the globe. There is surface enrichment of 210 Pb and 210 Po with respect to their progenitor 226 Ra as it is evident from the activity ratios of 210 Pb/ 226 Ra (3.03±1.79) and 210 Po/ 226 Ra (2.23±1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2 Bq/KXg and 21.9 Bq/KXg dry weight, respectively

Evaluating the distribution of the radioactive isotopes 226 Ra and 238 U in the ground water

International Nuclear Information System (INIS)

Bragea, M.

2006-01-01

By closing the mining activities huge quantities of waste rock stored in unprotected dump remained abandoned. As a result of the process of ore extraction, the waste rock and a very low percentage of metallic minerals were stored in tailing ponds, with a clay liner necessary to isolate the tailing from the rest of the aquifer. The migration of hazardous elements and radionuclides in groundwaters depends on the degree of their interaction with the surrounding rock material. This paper describes some of the experimental clay formations, to identify the main factors influencing the radioisotopes concentration and in a first approach to estimate the natural radionuclide intake levels by adult inhabitants of Ciudanovita region, Romania. Therefore we tried to study the extractive power of natural water in the existing depositing places. Several natural analogue laboratory models were set up, to study the dependence of washed quantity of radionuclides on the water amount washing the sample and mass of the samples. The effect of sorption on travel time was determined by comparing groundwater travel time (no sorption) with radionuclide travel time (includes sorption) The mechanism of releasing 226 Ra and 238 U from the minerals that compose the waste rock is influenced by the duration of the contact between the water and the waste rock, the composition of the water phase. Further on, the necessity of the paper is connected to the fact that the exchanges water-waste rock are complex processes, that depend on the environment conditions, each case can be a particular case. (author)

/sup 226/Ra in the western Indian Ocean

Energy Technology Data Exchange (ETDEWEB)

Chung, Y.

1987-09-01

/sup 226/Ra profiles have been measured in the western Indian Ocean as part of the 1977-78 Indian Ocean GEOSECS program. These profiles show a general increase in deep and bottom water Ra concentration from the Circumpolar region to the Arabian Sea. A deep Ra maximum which originates in the Arabian Sea and in the Somali basin at about 3000 m depth spreads southward into the Mascarene basin and remains discernible in the Madagascar and Crozet basins. In the western Indian Ocean, the cold Antarctic Bottom Water spreads northward under the possibly southward-flowing deep water, forming a clear benthic front along the Crozet basin across the Southwest Indian Ridge into the Madagascar and Mascarene basins. The Antarctic Bottom Water continues to spread farther north to the Somali basin through the Amirante Passage at 10/sup 0/S as a western boundary current. The benthic front and other characteristic features in the western Indian Ocean are quite similar to those observed in the western Pacific where the benthic front as a distinctive feature was first described by Craig et al. Across the Mid-Indian Ridge toward the Ceylon abyssal plain near the triple junction, Ra profiles display a layered structure, reflecting the topographic effect of the mid-ocean ridge system on the mixing and circulation of the deep and bottom waters. Both Ra and Si show a deep maximum north of the Madagascar Basin. Linear relationships between these two elements are observed in the deep and bottom water with slopes increasing northward. This suggests a preferential input of Ra over Si from the bottom sediments of the Arabian Sea and also from the flank sediments of the Somali basin.

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

International Nuclear Information System (INIS)

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 sites

Measurement by liquid scintillation of {sup 226} Ra coprecipitated in BaSO{sub 4}; Medicion por centelleo liquido de {sup 226} Ra coprecipitado en BaSO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Lopez del Rio, H.; Davila R, J.I.; Badillo A, V.E.; Mireles G, F.; Quirino T, L.; Lugo R, J.F.; Pinedo V, J.L.; Rios M, C. [UAEN-UAZ, A.P. 579C, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)]. e-mail: idavila@cantera.reduaz.mx

2003-07-01

The {sup 226} Ra is one of the more radio toxic nuclides since when entering to the organism it continues metabolically to the calcium, accumulating mainly in the bone tissue where it becomes in an internal radiation source. For the analysis of radium in water the methods of radon emanation are generally applied and coprecipitation with barium sulfate. This last is quick and efficient, and the radium in the precipitate can be measured by alpha or gamma spectrometry, or liquid scintillation dissolving the precipitate one with EDTA. In this work it is proposed a procedure for the radium measurement in water based on the coprecipitation with barium sulfate and in the detection by liquid scintillation. The precipitate of Ba(Ra)SO{sub 4} it is carried with water and blended with the liquid scintillator OptiPhase Hi Safe 3, avoiding the dissolution with EDTA. A 92{+-} 1.4% of radium it was recovered and it was reached a minimum activity detectable of 4.2 {+-} 0.9 mBq{sup -1}. The procedure was essayed with natural mineral water with a knew activity in concentration of {sup 226} Ra. The analytic result it coincided with the reported value with a relative error of 9%. (Author)

Determination of Ra-226 and Th-232 in samples of natural phosphates, industrial gypsums and surface soils by gamma spectrometry

International Nuclear Information System (INIS)

Pessenda, L.C.R.; Nascimento Filho, V.F. do; Nadai, E.A. de; Barros Ferraz, E.S. de; Sao Paulo Univ., Piracicaba

1988-01-01

The natural radioactivity in Ra-226 and Th-232 in samples of natural phosphates, industrial gypsums (phosphogypsums) and surface soils of different regions was measured by γ-ray spectrometry. The majority of phosphates and gypsums examined showed significantly higher values than soils, mainly in relation to Ra-226 activity. The activity ranges found for phosphates, gypsums and soils were: 79.1 - 3180 Bq/kg, 56.3 - 986.6 Bq/kg, 8.8 - 54.3 Bq/kg for Ra-226 and 33.6 - 1450.3 Bq/kg; 17.4 - 130,1 Bq/kg, 9.8 - 108.9 Bq/kg for Th-232, respectively. (author) [pt

Distribution of 226Ra body burden of workers in an underground uranium mine in India.

Science.gov (United States)

Patnaik, R L; Jha, V N; Kumar, R; Srivastava, V S; Ravi, P M; Tripathi, R M

2014-11-01

Uranium mine workers are exposed to ore dust containing uranium and its daughter products during different mining operations. These radionuclides may pose inhalation hazards to workers during the course of their occupation. The most significant among these radionuclides is (226)Ra. The measurement of radium body burden of uranium mine workers is important to assess their internal exposure. For this purpose, the radon-in-breath measurement technique has been used in the present paper. Workers at the Jaduguda mine, India, associated with different categories of mining operations were monitored between 2001 and 2007. The measurement results indicate that workers--depending on mining operation category--show (226)Ra body burdens ranging from 0.15 to 2.85 kBq. The maximum body burden was found for workers associated with timbering operations, with an average (226)Ra body burden of 0.85 ± 0.54 kBq. Overall, the average value observed for 800 workers was 0.76 ± 0.51 kBq, which gives rise to an average effective dose of 1.67 mSv per year for inhalation and 0.21 mSv per year for ingestion.

Seasonal variation of 226Ra and 222Rn in mineral spring waters of Aguas da Prata-Brazil

International Nuclear Information System (INIS)

Oliveira, J. de; Mazzilli, B.; Oliveira S, M.H de; Bernadete, S.

1996-01-01

Concentration levels of 226 Ra and 222 Rn have been analysed in most of the mineral spring waters available in the Aguas da Prata region, which is located in the Pocos de Caldas plateau, one of the biggest weathered alkaline intrusions of the world. In this plateau can be found many health resorts[based on springs of thermal and mineral waters. The Aguas da Prata spring waters show a large variety of composition. It has been observed bicarbonates, carbonates and sulphates salts in these mineral waters. The 226 Ra was determined by gross alpha counting of a Ba(Ra)SO 4 precipitate. The measurement was carried out in a low background gas flow proportional counter. The 222 Rn concentrations were determined by liquid scintillation method. Water samples were randomly collected at 9 spring sites over a period of one year, in order to evaluate the seasonal variation of these radionuclides. Lower concentrations were found mostly in the rainy season (summer), which presents 80% of the annual rainfall of the region (1500 mm/year). Higher concentrations up to 2223 mBq/L for 226 Ra and 131 Bq/L for 222 Rn have been observed in waters with low level of soluble salts. Waters which present high levels of carbonate and sulphate salts showed maximum values of 316 mBq/L for 226 Ra and 30 Bq/L for 222 Rn. This behaviour is mainly due to the physicochemical properties of these radionuclides in water as well as to the lithologic structure of the aquifers. (authors). 6 refs., 2 figs., 1 tab

Distribution of uranium, Ra-226, Pb-210 and Po-21a in the ecological cycle in mountain regions of central Yugoslavia

International Nuclear Information System (INIS)

Milosevic, Z.; Horsic, E.; Kljajic, R.; Bauman, A.

1980-01-01

The distributions of U, 226 Ra, 210 Pb and 210 Po in the ecological cycle: soil-hay-domestic animals-meat-cheese-milk were investigated. The levels of radioactivity in soil were found to be normal. The highest result found for U in hay was 100 ug/kg. The amount of 226 Ra was highest in beef bones, where the contamination reached 190 pCi/kg. The amount of 210 Pb in bones never exceeded 30 pCi/kg and in meat, 5 pCi/kg. In most samples 210 Po was below the detection level, but one bone sample reached 90 pCi/kg. U, 226 Ra, 210 Pb and 210 Po in milk all vary from 0 - 2.45 pCi/l. Only 210 Pb in cheese was as high as 60 pCi/kg, 226 Ra, 210 Po and U were hardly detectable. (H.K.)

Spatial distribution of natural and fallout level of 226Ra, 228Ra, 40K and 137Cs in grab sediments of Mumbai Harbour Bay

International Nuclear Information System (INIS)

Kumar, Ajay; Rout, Sabyasachi; Joshi, V.M.; Karpe, Rupali; Ravi, P.M.; Singhal, R.K.

2012-01-01

Radionuclides introduced from fall-out and nuclear installations into the marine surface water subjected to movement and mixing with tides and current, undergo horizontal dispersion, dilution and get bound to suspended particles by various physical, chemical, and biological processes. For this study, about 250 g of meshed grab sediments of eight sampling locations were transferred to a suitable cylindrical acrylic container, sealed and kept for 30 days to allow for in-growth of radon gas in order to achieve secular equilibrium between 226 Ra, 214 Pb and 214 Bi in the 238 U decay chain and between 212 Pb, 208 TI and 228 Ac in the 232 Th decay chain. The activity concentrations of 226 Ra, 228 Ra, 40 K and 137 Cs were measured using Gamma spectrometry system

Concentration Of 228Th, 226Ra, And 40K Radionuclides In Drinking Water In Southern Sumatera

International Nuclear Information System (INIS)

Sutarman; Warsono, Asep; Wahyudi

2000-01-01

Measurements of 228 Th, 226 Ra, and 40 K concentrations in drinking water on several places in Southern Sumatera (1997-1999) have been carried out. The sample were collected from the Province of Lampung (Kalianda, Bandar Lampung, Kotabumi, Talangpadang, Kotaagung, Liwa, Manggala, and Pakuanratu), and the Province of Southern Sumatera (Palembang-1, Palembang-2, Plaju, Lahat, and Sekayu). Measurements of 228 Th, 226 Ra, and 40 K concentrations in drinking water using the gamma spectrometer with the HP-Ge detector. The results of measurement showed that the concentration was the range of undetectable ( 228 Th concentration, the range of undetectable ( 226 Ra, radionuclide and the range of undetectable (< 128.96 mBq/l) to (880.54 n 22.75) mBq/l with average of (412.12 n 5.02) mBq/l, and the data mentioned above were still far under the maximum permissible concentration. The estimated of annual dose equivalent effective in drinking water was 0.03 mSv/year for public (5 mSv/year)

Determination of the 226Ra, 228Ra and 210Pb concentrations in the mineral water springs from water parks of Cambuquira and Marimbeiro, Minas Gerais and assessment of the committed effective doses

International Nuclear Information System (INIS)

Santos, Laíssa A.B. dos; Damatto, Sandra R.

2017-01-01

Due to the importance of human life, water quality must be controlled and a very important parameter are the limits of the natural radioactivity of the water consumed. In relation to therapeutic practices based on water intake the radionuclides 210 Pb, 226 Ra and 228 Ra when present, are of great importance because they contribute to the internal irradiation of individuals.The study areas of the present work were the Parque das águas of Cambuquira and Marimbeiro, located in Minas Gerais. Hence, the objective of this work was to determine the 226 Ra, 228 Ra and 210 Pb concentrations in the springs of these parks and evaluate the committed effective doses due to its consumption.The radionuclides were determined by a radiochemical procedure in four collections at different seasons of the year. The Concentrations ranged from 4 ± 1 mBq / L to 509 ± 32 mBq / L for 226 Ra, from 3.7 ± 0.1 mBq / L to 631 ± 27 mBq / L for 228 Ra and 5 ± 1 mBq / L to 60 ± 5 mBq / L for 210 Pb. The dose for adults from 1.21 x 10 -01 mSv/y for 226 Ra, 3.18 x 10 -01 mSv/y for 228 Ra and for 210 Pb 3.02 x 10 -02 mSv/y. (author)

Estimation of 226Ra and U(Nat) in sediment off Mumbai coast

International Nuclear Information System (INIS)

Sugandhi, S.; Ravi, P.M.; Wankhede, Sonal

2012-01-01

Bottom sediment in a marine system is formed from organic and inorganic particles which settle from water of aquatic media. The sediment compartment is the receptor of radionuclides and it indicates the impact of pollution. Radioactive materials like Ra and U are normal constituents of earths crust. The present study was done to estimate 226 Ra and U(Nat) from various locations in sediment off Mumbai coast. The levels of 226 Ra in sediments of Mumbai coast has been observed to be between 3.8 to 26.0 Bq/kg with a mean averaged value of 13.3 Bq/kg which is similar to the sediment at Bay of Bengal (13.9 to 25.9 Bq/kg), Indian Ocean (13.8 Bq/kg), Arabian Sea (16.9 to 31.7 Bq/kg), Egyptian Red sea coast (27.4 Bq/kg). Uranium content in sediment was found to be in the range of 16.3 to 56.3 Bq/kg with an averaged mean of 32.2 Bq/kg. It is observed that, uranium concentration is higher than radium concentration in sediment. This may be attributed to the relatively higher mobility of radium as compared to uranium in an aquatic environment

Measurement by liquid scintillation of 226 Ra coprecipitated in BaSO4

International Nuclear Information System (INIS)

Lopez del Rio, H.; Davila R, J.I.; Badillo A, V.E.; Mireles G, F.; Quirino T, L.; Lugo R, J.F.; Pinedo V, J.L.; Rios M, C.

2003-01-01

The 226 Ra is one of the more radio toxic nuclides since when entering to the organism it continues metabolically to the calcium, accumulating mainly in the bone tissue where it becomes in an internal radiation source. For the analysis of radium in water the methods of radon emanation are generally applied and coprecipitation with barium sulfate. This last is quick and efficient, and the radium in the precipitate can be measured by alpha or gamma spectrometry, or liquid scintillation dissolving the precipitate one with EDTA. In this work it is proposed a procedure for the radium measurement in water based on the coprecipitation with barium sulfate and in the detection by liquid scintillation. The precipitate of Ba(Ra)SO 4 it is carried with water and blended with the liquid scintillator OptiPhase Hi Safe 3, avoiding the dissolution with EDTA. A 92± 1.4% of radium it was recovered and it was reached a minimum activity detectable of 4.2 ± 0.9 mBq -1 . The procedure was essayed with natural mineral water with a knew activity in concentration of 226 Ra. The analytic result it coincided with the reported value with a relative error of 9%. (Author)

Biomass selection for biosorption study of {sup 226} Ra and {sup 137} Cd radionuclides; Selecao de biomassas para o estudo da biossorcao dos radionuclideos {sup 226} Ra e {sup 137} Cs

Energy Technology Data Exchange (ETDEWEB)

Costa, Wilson Cervi da

2003-07-01

The main goal of this work was to verify the potentialities to apply the biosorption technique to synthetic and real solution containing {sup 226} Ra and {sup 137} Cs, utilizing the seaweed Sargassum sp. and the microorganisms Penicillium sp., Saccharomyces cerevisiae and Monoraphidium sp. Indeed, the screening of the most effective biomass to remove the radionuclides was also a central objective. {sup 226} Ra was selected due to its high radiotoxicity and the fact that it can be assimilated and incorporated by living organism through substitution og Mg{sup 2+} and Ca{sup 2+}, two essential nutrients. On the other hand, the selection of {sup 137} Cs, a radionuclide of medium toxicity, was due to its mobility in the environment, which increases the possibility to be assimilated by the organisms as the essential nutrients Na{sup +} and K{sup +}. (author)

Determination of 226Ra and 224Ra in sediments samples by liquid scintillation counting

International Nuclear Information System (INIS)

Villa, M.; Moreno, H.P.; Manjon, G.

2005-01-01

An experimental procedure has been developed for a rapid determination of the activity concentration of 226 Ra and 224 Ra in sediments by liquid scintillation counting. The importance of the method lies in its application to the measurement of sediments where the Ra-isotopes activity concentration has been increased due to an anthropomorphic enhancement based on releases of naturally occurring radioactive material (NORM). A sample pre-treatment, including a digestion with aqua regia and a precipitation of hydroxides, was applied to samples before the radium extraction, which was made by co-precipitation with barium. Measurements were done in a low background scintillation spectrometer Quantulus 1220, which can separate and detect simultaneously α and β particles. Additionally, some improvements are suggested for a better α and β interference correction of the results. The obtaining of radiochemical yields is also improved using 133 Ba as tracer, which decays by emission of conversion electrons and γ-rays; the wide range of radiochemical yields obtained confirms the need of this analyses. The procedure has been applied to the measurement of riverbed sediments from an estuary in the south-west of Spain, affected in the past by direct and indirect phosphogypsum discharges

Behaviour of {sup 238}U, {sup 234}U, {sup 228}Ra and {sup 226}Ra in rock alterations: study of Morungaba granitoids, SP-Brazil and ground water in its fractures; Comportamento de {sup 238}U, {sup 234}U, {sup 228}Ra e {sup 226}Ra na alteracao de rochas: estudo dos granitoides de Morungaba (SP) e aguas subterraneas de suas fraturas

Energy Technology Data Exchange (ETDEWEB)

Santos, Rosana N. dos [Pontificia Univ. Catolica de Sao Paulo, SP (Brazil). Dept. de Fisica]. E-mail: rosana@pucsp.br; Marques, Leila S. [Sao Paulo Univ., SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Geofisica]. E-mail: leila@iag.usp.br

2005-07-01

This work presents the first results obtained on the investigation of the behavior of uranium and radium radioisotopes in the processes of weathering and rock-water interaction of Morungaba granitoids belonging to Meridional Pluton (Valinhos Town-SP-Brazil). Specific activities of {sup 238}U, {sup 234}U, {sup 228}Ra and {sup 226}Ra were determined in non altered granitoids (Group A), as well as in those affected by different degrees of weathering (Groups B, C and D). The uranium specific activities were determined by alpha spectrometry method, whereas for the determination of radium isotopes high resolution gamma-ray spectrometry technique was employed. The data indicate that {sup 238}U and {sup 234}U are in radioactive equilibrium in the fresh analyzed granitoids, but show a slight depletion of {sup 234}U in relation to {sup 238}U in the weathered rocks. The ({sup 226}Ra/{sup 238}U) and ({sup 226}Ra/{sup 234}U) activity ratios of all investigated rocks are similar, showing a significant {sup 226}Ra depletion, which is probably caused by its preferential leaching. These results indicate that even samples macroscopically classified as fresh rocks, their systems have been opened for some geochemical changes. The high ({sup 234}U/{sup 238}U) activity ratios of groundwaters which are found in the fractures of these granitoids suggest their prolonged residence times in the aquifer and/or their percolation by other rocks presenting different geochemical properties. (author)

Concentrations and environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks and accumulation in sludge, New Jersey Coastal Plain, USA

Science.gov (United States)

Szabo, Z.; Jacobsen, E.; Kraemer, T.F.; Parsa, B.

2008-01-01

Concentrations of Ra in liquid and solid wastes generated from 15 softeners treating domestic well waters from New Jersey Coastal Plain aquifers (where combined Ra (226Ra plus 228Ra) concentrations commonly exceed 0.185 Bq L-1) were determined. Softeners, when maintained, reduced combined Ra about 10-fold (septic-tank effluents receiving brine waste were less than in the untreated ground waters. The maximum combined Ra concentration in aquifer sands (40.7 Bq kg-1 dry weight) was less than that in sludge from the septic tanks (range, 84-363 Bq kg-1), indicating Ra accumulation in sludge from effluent. The combined Ra concentration in sludge from the homeowners' septic systems falls within the range reported for sludge samples from publicly owned treatment works within the region.

Ra-226, Pb-210, and Po-210 in the Black Forest

International Nuclear Information System (INIS)

Schuettelkopf, H.; Kiefer, H.

1981-01-01

By measuring Pb-210, Po-210 and Ra 226 in air, water, ground, plants, and food samples the concentration ranges of the radionuclide and the transfer factor important for the calculation of the ingestion dose of man were determined. Po 210 was found to have the lowest radiotoxicity. The highest Po-210 concentrations were found in protein-containing food. (DG) [de

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

International Nuclear Information System (INIS)

Bonotto, D.M.

2004-01-01

Groundwater samples were analysed for 222 Rn, 226 Ra, and 228 Ra in Guarani aquifer spreading around 1 million km 2 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

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

Science.gov (United States)

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.

230Th/238U and 226Ra/230Th fractionation in young basaltic glasses from the East Pacific Rise

International Nuclear Information System (INIS)

Reinitz, I.; Turekian, K.K.

1989-01-01

Mid-ocean ridge basalt (MORB) glasses treated to remove manganese and iron oxyhydroxide coatings containing U and Th decay chain nuclides sequestered from the ambient aqueous environment show little fractionation of ( 230 Th) from ( 238 U), but extensive enrichment of ( 226 Ra) over ( 230 Th). Chronometry based on ( 230 Th)-( 238 U) disequilibrium yields a mean age of 151,000 ± 55,000 (2σ) years ago for Th-U fractionation, from a source region with Th/U (atom ratio) = 1.58 ± 0.43 (2σ). ( 226 Ra) excesses over ( 230 Th) indicate an enrichment event more recent than the fractionation of Th from U. ( 226 Ra/ 230 Th) correlates well with K/U, providing a rough means of estimating the age since eruption of MORB glasses. (orig.)

On alpha activity relationships in 226Ra and U/sub nat/

International Nuclear Information System (INIS)

Krejbichova, Z.

1982-01-01

A gross alpha activity of 0.1 Bq/l is permitted for drinking and surface waters. If gross activity is higher, it is suitable to determine the 226 Ra content which must not exceed 0.1 Bq/l. The permissible content of natural uranium is 0.05 mg/l. In most samples of ground and surface waters gross alpha activity was below the permissible limit. In some samples with a high content of salts a higher Ra+U activity was found which exceeded gross activity. This was caused by the interference of nonradioactive admixtures. In other samples a higher gross alpha activity was found than was the sum Ra+U which may have been caused by alpha sources from radon decay. It was found that the gross alpha activity of waters is rather caused by uranium than by radium. (E.S.)

Distribution of 137Cs and 226Ra in the sediments of Aswan High Dam lake

International Nuclear Information System (INIS)

Ismail, S.S.; Unfried, E.; Grass, F.

1994-01-01

Sediment samples of the High Dam lake were investigated for their 137 Cs, 226 Ra, 228 Th, and 40 K content, using low-level γ-spectroscopy. The results show that at the beginning of the lake (500 km from the High Dam), where sediments consist mostly of sand, the level of 137 Cs is very low (0.1 Bq*kg -1 ). The maximum value (22.3 Bq*kg -1 ) was found 40 km from the wall of the High Dam, where the composition of the sediments is nearly 50% clays. The distribution of the natural nuclides 226 Ra, 228 Th and 40 K shows a different trend. (author) 9 refs.; 9 figs.; 1 tab

{sup 226}Ra activity standardization by 4παβ(LS)-γ(NaI-Tl) anticoincidence counting

Energy Technology Data Exchange (ETDEWEB)

Silva, C.J. da; Poledna, R.; Santos, A.R.L.; Gomes, R.S., E-mail: carlos@ird.gov.br [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratório Nacional de Metrologia das Radiações Ionizantes

2017-07-01

From a commercial supplier a solution containing {sup 226}Ra has been standardized at National Laboratory for Ionizing Radiation Metrology (LNMRI) for the first time using Liquid scintillation based measurement. The measurement methods are 4παβ-γ live-timed anticoincidence counting. The results obtained by anticoincidence counting were adopted as reference value and its combined uncertainty was 0.94 %. The agreement of this reference value with reference system with ionization chamber was 0.56 %. This standardization was made in order to reduce the uncertainty in {sup 226}Ra measurement in Brazil. (author)

Measurement of 226Ra, 228Ra, 137CS and 40K in edible parts of two types of leafy vegetables cultivated in Tehran province-Iran and resultant annual ingestion radiation dose

International Nuclear Information System (INIS)

Changizi, V.; Jafarpoor, Z.; Naseri, M.

2010-01-01

The sources of radioactivity in the environment have natural; terrestrial and extraterrestrial. and anthropogenic origins. Plants may get radioactive nuclides in two ways: (i) by the deposition of radioactive fallout, (ii) by absorption from the soil. Materials and Methods: The Concentrations of the natural radionuclides ( 226 Ra, 228 Ra, 40 K) and the artificial radionuclide ( 137 CS) in leek and parsley in Tehran province-Iran were determined using high-purity Ge detectors. Also the effective dose due to the ingestion of such vegetables by the population of Tehran province was studied. Results: The average value of radionuclide concentrations in parsley samples were measured 177.69 ± 12.47 mBq kg -1 fresh for 226 Ra; 349.62 ± 28.42 mBq kg -1 fresh for 228 Ra; 187364.6 mBq kg 1 fresh for 40 K. The average value of radionuclide concentrations in leek samples were measured 94.31 ± 6.46 mBq kg -1 fresh for 226 Ra; 207.47 ± 19.46 mBq kg -1 fresh for 228 Ra; 174555 ± 1704.21 mBq kg -1 fresh for 40 K. The concentrations of 137 Cs in most of Parsley and Leek samples were below the minimum detectable activity. Conclusion: The Average 226 Ra and 228 Ra activities in 29 leek and parsley samples were about 2.63 and 6.78 times the reference values, respectively. The annual effective dose resulting from the studied radionuclides for the adult population in Tehran province were found to be safe in comparison with normal background areas.

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

International Nuclear Information System (INIS)

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 226 Ra 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 226 Ra 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 SiO 2 -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 226 Ra contents include (in decreasing order): aplites, granites, gneisses and leucogranites, granite-gneisses, granodiorites and rhyolites, and, finally, mudstones. The lowest values of 226 Ra 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 226 Ra 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

Determination of specific activities of U-238, Ra-226, Ra-228 e Th-228 in samples of mineral fertilizers with phosphorus; Determinacao das atividades especificas de U-238, Ra-226, Ra-228 e Th-228 em amostras de fertilizantes minerais com fosforo

Energy Technology Data Exchange (ETDEWEB)

Garcez, R.W.D.; Lopes, J.M.; Silva, A.X. da, E-mail: rgarcez@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharoa (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Domingues, A.M.; Lima, M.A.F. [Universidade Federal Fluminense (UFF),Niteroi, RJ (Brazil)

2016-07-01

Samples were analyzed by gamma spectrometry mineral fertilizers with the HPGe detector and aid LabSOCS software for calculating the detection efficiency curve. Specific activities found for Pa-234m, Ra-226, Ra-228 and Th-228 in samples of phosphate fertilizers were 505 Bq.kg{sup -1}, 458 Bq.kg{sup -1}, 450 Bq.kg{sup -1} and 394 Bq.kg{sup -1}, respectively. And for the NPK fertilizer samples were found average values of 390 Bq.kg{sup -1}, 252 Bq.kg{sup -1}, 280 Bq.kg{sup -1} and 268 Bq.kg{sup -1}, respectively. (author)

Distribution of {sup 226}Ra body burden of workers in an underground uranium mine in India

Energy Technology Data Exchange (ETDEWEB)

Patnaik, R.L.; Jha, V.N.; Kumar, R.; Srivastava, V.S.; Ravi, P.M.; Tripathi, R.M. [Bhabha Atomic Research Centre, Health Physics Unit, Jaduguda, Jharkhand (India)

2014-11-15

Uranium mine workers are exposed to ore dust containing uranium and its daughter products during different mining operations. These radionuclides may pose inhalation hazards to workers during the course of their occupation. The most significant among these radionuclides is {sup 226}Ra. The measurement of radium body burden of uranium mine workers is important to assess their internal exposure. For this purpose, the radon-in-breath measurement technique has been used in the present paper. Workers at the Jaduguda mine, India, associated with different categories of mining operations were monitored between 2001 and 2007. The measurement results indicate that workers - depending on mining operation category - show {sup 226}Ra body burdens ranging from 0.15 to 2.85 kBq. The maximum body burden was found for workers associated with timbering operations, with an average {sup 226}Ra body burden of 0.85 ± 0.54 kBq. Overall, the average value observed for 800 workers was 0.76 ± 0.51 kBq, which gives rise to an average effective dose of 1.67 mSv per year for inhalation and 0.21 mSv per year for ingestion. (orig.)

Influence of soil texture on the distribution and availability of 238U, 230Th, and 226Ra in soils

International Nuclear Information System (INIS)

Blanco Rodriguez, P.; Vera Tome, F.; Lozano, J.C.; Perez-Fernandez, M.A.

2008-01-01

The influence of soil texture on the distribution and availability of 238 U, 230 Th, and 226 Ra in soils was studied in soil samples collected at a rehabilitated uranium mine located in the Extremadura region in south-west Spain. The activity concentration (Bq kg -1 ) in the soils ranged from 60 to 750 for 238 U, from 60 to 260 for 230 Th, and from 70 to 330 for 226 Ra. The radionuclide distribution was determined in three soil fractions: coarse sand (0.5-2 mm), medium-fine sand (0.067-0.5 mm), and silt and clay ( 238 U, 230 Th, and 226 Ra between the activity concentration per fraction and the total activity concentration in the bulk soil. Thus, from the determination of the activity concentration in the bulk soil, one could estimate the activity concentration in each fraction. Correlations were also found for 238 U and 226 Ra between the labile activity concentration in each fraction and the total activity concentration in bulk soil. Assuming that there is some particle-size fraction that predominates in the process of soil-to-plant transfer, the parameters obtained in this study should be used as correction factors for the transfer factors determined from the bulk soil in previous studies

Rapid analysis of 226Ra in mine waters by gamma-ray spectrometry. Supervising Scientist report 103

International Nuclear Information System (INIS)

Johnston, A.; Martin, P.

1995-01-01

Techniques for the determination of 226 Ra in uranium mine waters by γ-ray spectrometry are examined with an emphasis on methods capable of completion within 1 to 3 days of receipt of the sample. Methods discussed utilise either: (i) the 186 keV 226 Ra γ-ray, with the contribution from 235 U being subtracted after a separate uranium determination, or (ii) measurement of ingrowing 222 Rn progeny, either by two successive counts or by a single count (together with an assumption that radon was not present at the time of sample preparation). A full analysis of the statistical uncertainties and systematic errors associated with each technique is presented

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

Directory of Open Access Journals (Sweden)

N. Tisnérat-Laborde

2012-03-01

Full Text Available 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

Estimation of Ra-226, Ra-228 and K-40 specific activities in fertilizer samples marketed in the Rio de Janeiro City

Energy Technology Data Exchange (ETDEWEB)

Garcêz, R.W.D.; Lopes, J.M.; Silva, A. X. da, E-mail: rgarcez@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (LAASC/UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Nuclear; Lima, M.A.F. [Universidade Federal Fluminense (LARA/UFF), Niterói, RJ (Brazil). Departeamento de Biologia

2017-07-01

The use of fertilizers is a common practice in agriculture and several samples have radionuclides in their composition. This content is natural but some samples may have high concentrations of these radionuclides and this represent a potential radiological risk for plants, animals and water. Therefore, the radiometric analyses of these compounds is important, and the aim of this paper is to determine the specific concentration of K-40, Ra-226 and Ra-228 in fertilizer samples available in market of Rio de Janeiro city and discussing the impacts to agricultural soils caused by this practice. Four types of fertilizer samples were analyzed: nitrogen, potash, phosphate and NPK. They were analyzed through gamma spectroscopy technique with a HPGe detector and with the LabSOCS software for the calculation of the efficiency curve. The specific activities of Ra-226 ranged from 1.48 to 597 Bq/kg, Ra-228 ranged from 2.66 to 832 Bq/kg and K-40 ranged from 16 to 13941 Bq/kg. All samples, except two of nitrogen fertilizer, presented the absorbed dose rate in air, at 1m above the ground level, higher than the estimated average global terrestrial radiation for soil (51 nGy/h) and the phosphate fertilizer samples presented the highest average absorbed dose rate: 532.5 nGy/h, which indicates a greater potential of environmental contamination. (author)

Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples.; Determinacion de U (Natural), Th (Natural) y Ra-226 en diversos materiales, mediante espectrometria con INa (TI)

Energy Technology Data Exchange (ETDEWEB)

Salvador, S.; Navarro, T.; Alvarez, A.

1991-07-01

A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs.

Absorption and removal of Ra-226, Pb-210 and Po-210 by humans and the resulting radiation exposure

International Nuclear Information System (INIS)

Gloebel, B.; Berlich, J.; Andres, C.

1985-01-01

In over 400 samples (food, water, air, stools and urine), the concentration of Ra-226, Pb-210 and Po-210 was measured. The daily intake for the three nuclides is: Ra-226: 30 mBq; Pb-210: 150 mBq; Po-210: 150 mBq. The table shows intake of individual food and drinking items as well as air. In all but the kidney samples, Pb and Po were present in radioactive equilibrium. The contribution of each radionuclide to radiation exposure is indicated. (orig./HP) [de

Determination of {sup 226}Ra by gamma spectrometry: study of packaging vial of sample for analysis; Determinacao de {sup 226}Ra por espectrometria gama: estudo do recipiente de acondicionamento de amostra para analise

Energy Technology Data Exchange (ETDEWEB)

Carneiro, Andre Cavalcanti

2015-07-01

Determination of radioactivity levels of {sup 226}Ra by gamma spectrometry in a sample is based on measurements of {sup 214}Pb and {sup 214}Bi, daughters of {sup 222}Rn. Because radon is a gas, it can leak from the sample vial or accumulate on the upper empty it. If the vial has any crack, there will be loss of gas, which will cause error in determining the {sup 226}Ra concentration. One possible cause of cracks in the vials, that houses standards and samples, is the radiolysis action in the vial material, usually a polymer. As the demand {sup 226}Ra analysis in different matrices (geological samples, food, plants, etc.) is increasing, it was decided to study some polymer vials available on the market, to verify the feasibility to be used when is applied the analysis method using gamma spectrometry. Four types of polymer vials have been studied. The radiation doses in walls of the vials caused by natural radionuclides present in the sample were simulated using gamma irradiation. Tests, such as compressive strength test and tightness, were applied to the irradiated and non-irradiated vials. First, to verify the effect of radiolysis on the vial material and also if there was {sup 222}Rn diffusion in their walls. These preliminary results pointed out that the acrylic vials are the best option of packaging samples for analysis. This study should be repeated in a larger number of samples for a better evaluation. (author)

226Ra and 210Pb relationship in solid wastes and plants at Uranium mill tailing

International Nuclear Information System (INIS)

Madruga, M.J.; Faria, I.; Brogueira, A.

2002-01-01

After the uranium extraction from the ore, the waste residues (tailings) contain several radionuclides in elevated levels comparing to normal soils. Nearly all of the uranium progenies (2 30T h, 2 26R a, 2 10P b and 2 10P o) and the unextracted uranium fraction are present in tailings. These large quantities of tailings may provide a significant source of environmental and food chain contamination. The transfer of radioisotopes between different ecological compartments is frequently evaluated using ratios which relate the radionuclide content in one ecosystem compartment to that of another. For instance, the concentration ratio (CR), i.e., the ratio between radionuclide concentrations in tailings and plants can be evaluated. Radium-226, a long-lived alfa emitter, is a chemical analog of calcium. The 2 26R a uptake is similar to calcium in biological and ecological systems. The uptake of 2 10P b will follow the same pattern as natural lead. Plants do not require lead but in contrast they require the Ra/Ca group elements. The uptake of lead is mainly a function of the lead tolerance of the plant and the hydrogen ion concentration of the soil. Kalin and Sharma (1982) reported that 2 26R a and 2 10P b uptake by indigenous species from inactive uranium mill tailings in Canada differ from the uptake of the elements by the same plants growing in soil. Ibrahim and Whicker (1992) reported that tailing acidity tends to enhance radionuclide availability for plant uptake. The transport of radionuclides to foliage and subsequent retention and absorption may play a role in plant contamination. The main goal of this study is to evaluate the 2 26R a and 2 10P b relationship in tailings and plants growing at uranium mill tailings

Behavior of Ra-226 and Pb-210 in the aquatical environment of the first Brazilian uranium mine and mill

International Nuclear Information System (INIS)

Franca, E.P.; Amaval, E.C.S.; Stoffel, M.G.

1982-01-01

The first Brazilian uranium mine and mill will start operation in 1981, on the Pocos de Caldas plateau, in the central state of Minas Gerais. The pre-operational environmental survey indicated that the critical radionuclides in the region will be: 226 Ra due to the tailing pond liquid effluent and 21 Pb produced via 222 Rn dispersion, natural fall-out and accumulation on the ground. Sorption and desorption studies of 226 Ra and 210 Pb on their interaction with local water, suspended matter and sediments have been carried out in the laboratory to understand their behavior in the regional aquatic environment. The laboratory experiments gave indications that, in the aquatic environment of Pocos de Caldas, 210 Pb should remain mostly sorbed on bottom sediments. Its transport should occur essentially bound to suspended matter. By contrast, 226 Ra should be transported mostly in the soluble form

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Daily ingestion of 232Th, 238U, 226Ra, 228Ra and 210Pb in vegetables by inhabitants of Rio de Janeiro City

International Nuclear Information System (INIS)

Santos, E.E.; Lauria, D.C.; Amaral, E.C.S.; Rochedo, E.R.

2002-01-01

The concentrations of the naturally occurring radionuclides 232 Th, 238 U, 210 Pb, 226 Ra and 228 Ra were determined in the vegetables (leafy vegetables, fruit, root, bean and rice) and derived products (sugar, coffee, manioc flour, wheat flour, corn flour and pasta) consumed most by the adult inhabitants of Rio de Janeiro City. A total of 88 samples from 26 different vegetables and derived products were analyzed. The highest contribution to radionuclide intake arises from bean, wheat flour, manioc flour, carrot, rice, tomato and potato consumption. The estimated daily intakes due to the consumption of vegetables and derived products are 1.9 mBq of 232 Th (0.47 μg), 2.0 mBq of 238 U (0.17 μg), 19 mBq of 226 Ra, 26 mBq of 210 Pb and 47 mBq of 228 Ra. The estimated annual effective dose due to the ingestion of vegetables and their derived products with the long-lived natural radionuclides is 14.5 μSv. Taking into account literature data for water and milk from Rio de Janeiro the dose value increases to 29 μSv, with vegetables and derived products responsible for 50% of the dose and water for 48%. 210 Pb (62%) and 228 Ra (24%) were found to be the main sources for internal irradiation

Determination of natural radionuclides, U, Th-232, Ra-226, Ra-228, Pb-210 and K-40 in sediments from CananÉIa-Iguape System, Brazil

International Nuclear Information System (INIS)

Jesus, Gleyka J.D.; Chiozzini, Vitor G.; Saueia, Cátia H.R.; Nisti, Marcelo B.; Braga, Elisabete S.; Fávaro, Deborah I.T.; Universidade de São Paulo

2017-01-01

The Cananéia-Iguape estuarine-lagoon complex, located in the south of São Paulo State, Brazil, is a protected area recognized by UNESCO as part of the Biosphere Reserve, due to its importance as a natural ecosystem. However, along the years, the mining activities in the region affected the river basin, to such an extent that contamination was observed for As, Cu, Pb and Zn. Since the mining activities can also enhance the levels of natural radioactivity in the sediments, this study aimed to determine the activity concentration of the natural radionuclides (K-40, U, Ra-226, Pb-210, Th-232 and Ra-228) in 34 bottom sediments samples collected in the Cananéia-Iguape system. The samples were measured by gamma spectrometry, using a HPGe for the determination of K-40, Ra-226, Pb-210 and Ra-228. The concentration of U and Th-232 was determined by instrumental neutron activation analysis. The activity concentration of K-40 varied from 119 ± 17 to 522 ± 74 Bq kg"-"1; U-238 varied from 0.31 ± 0.05 to 5.8 ± 0.3 mg kg"-"1; Ra-226 varied from 3.7 ± 0.3 to 43.3 ± 1.5 Bq kg"-"1; Pb-210 varied from 5.8 ± 2.6 to 118 ± 12 Bq kg"-"1; Th-232 varied from 0.67 ± 0.02 to 16.6 ± 0.4 mg kg"-"1 and Ra-228 varied from 3.5 ± 0.6 to 64.9 ± 2.4 Bq kg"-"1. These results were compared with literature values for the region, indicating that they are the background of the region and no contamination was observed from NORM (Naturally Occurring Radioactive Material) industries. (author)

Determination of natural radionuclides, U, Th-232, Ra-226, Ra-228, Pb-210 and K-40 in sediments from CananÉIa-Iguape System, Brazil

Energy Technology Data Exchange (ETDEWEB)

Jesus, Gleyka J.D.; Chiozzini, Vitor G.; Saueia, Cátia H.R.; Nisti, Marcelo B.; Braga, Elisabete S.; Fávaro, Deborah I.T., E-mail: gjdjesus@ipen.br, E-mail: chsaueia@ipen.br, E-mail: mbnisti@ipen.br, E-mail: defavaro@ipen.br, E-mail: vitor.chio@usp.br, E-mail: edsbraga@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Universidade de São Paulo (USP), SP (Brazil). Instituto Oceanográfico

2017-07-01

The Cananéia-Iguape estuarine-lagoon complex, located in the south of São Paulo State, Brazil, is a protected area recognized by UNESCO as part of the Biosphere Reserve, due to its importance as a natural ecosystem. However, along the years, the mining activities in the region affected the river basin, to such an extent that contamination was observed for As, Cu, Pb and Zn. Since the mining activities can also enhance the levels of natural radioactivity in the sediments, this study aimed to determine the activity concentration of the natural radionuclides (K-40, U, Ra-226, Pb-210, Th-232 and Ra-228) in 34 bottom sediments samples collected in the Cananéia-Iguape system. The samples were measured by gamma spectrometry, using a HPGe for the determination of K-40, Ra-226, Pb-210 and Ra-228. The concentration of U and Th-232 was determined by instrumental neutron activation analysis. The activity concentration of K-40 varied from 119 ± 17 to 522 ± 74 Bq kg{sup -1}; U-238 varied from 0.31 ± 0.05 to 5.8 ± 0.3 mg kg{sup -1}; Ra-226 varied from 3.7 ± 0.3 to 43.3 ± 1.5 Bq kg{sup -1}; Pb-210 varied from 5.8 ± 2.6 to 118 ± 12 Bq kg{sup -1}; Th-232 varied from 0.67 ± 0.02 to 16.6 ± 0.4 mg kg{sup -1} and Ra-228 varied from 3.5 ± 0.6 to 64.9 ± 2.4 Bq kg{sup -1}. These results were compared with literature values for the region, indicating that they are the background of the region and no contamination was observed from NORM (Naturally Occurring Radioactive Material) industries. (author)

Application of ICP-QMS for the determination of ultratrace-levels of 226Ra in geothermal water and sediment samples

International Nuclear Information System (INIS)

Tsuey-Lin Tsai; Tsung-Yuan Wang; Hwa-Jou Wei; Lee-Chung Men; Chun-Chih Lin

2010-01-01

A rapid, accurate and less labor intensive approach to determining 226 Ra in environmental samples was examined; this utilized quadrupole-based inductively coupled plasma mass spectrometry (ICP-QMS). The procedure used chemical separation by ion exchange chromatography to remove most of the matrices after coprecipitation with BaSO 4 . The average chemical recovery of the NIST SRM preparation method ranged from 60.5 to 85.9% using 133 Ba as internal tracer by gamma counting. This technique was capable of completing a 226 Ra measurement within 3 min. It did not require an in-growth period to allow radon and its progeny to achieve secular equilibrium with the parent 226 Ra as is needed for liquid scintillation analyzer (LSA). The method detection limits for the determination of 226 Ra in geothermal water and sediment samples were 0.02 mBq L -1 (0.558 fg L -1 ) and 0.10 Bq kg -1 (2.79 fg g -1 ), respectively. The results obtained with various natural samples and the suitability of the method when applied to various environmental matrices such as geothermal water and sediment are discussed. When ICP-QMS was compared to double-focusing magnetic sector field inductively coupled plasma mass spectrometry (ICP-SFMS), good agreement was obtained with a correlation coefficient, r 2 = 0.982. (author)

Measurements of Ra-226 content of water and drinks in West Germany

International Nuclear Information System (INIS)

Glaum, F.; Schastok, J.

1986-01-01

The contamination of the population by Ra 226 in water and drinks can be excluded as a potential source of danger. Average values in pCi/litre: Mineral water - 1.17, spa water - 2.55, beer - 0.57, wine - 0.92, milk - 0.08, tapwater - 0.11, waste water a) incoming - 0.22 b) outgoing - 0.14, activation basin - 1.2. The whole body equivalent doses and annual activity supply for an intake of 440 litres/annum to be expected are: Mineral water - 1.6x10 -4 Sv/a, 5.1x10 -10 Ci/a, spa water - 3.5x10 -4 Sv/a, 1.1x10 -9 Ci/a, beer - 7.8x10 -5 Sv/a, 2.5x10 -10 Ci/a, wine - 1.3x10 -4 Sv/a, 4.0x10 -10 Ci/a, milk - 1.1x10 -5 Sv/a, 3.5x10 -11 Ci/a, tapwater - 1.5x10 -5 Sv/a, 4.8x10 -4 Ci/a. (HP) [de

Modeling of 226Ra behavior in a Spanish estuary affected by the phosphate industry

International Nuclear Information System (INIS)

Perianez, R.; Absi, A.; Manjon, G.; Villa, M.; Moreno, H.P.

2007-01-01

The Odiel and Tinto rivers, southwest Spain, form a fully mixed estuary. An industrial area that includes a complex dedicated to the production of phosphate fertilizers is located by the Odiel River. This complex released phosphogypsum wastes directly to the Odiel River and also disposed them on open air piles located by the Tinto River. Due to new EU regulations, wastes are not directly released to the Odiel from 1998 on, although they are still disposed on the open air piles. The behavior of 226 Ra in a system like this estuary is complex, since radionuclides are affected by tidal actions and interactions with sediments through adsorption/desorption reactions and erosion/deposition processes. A numerical 2D depth-averaged model of the estuary has been developed, including processes mentioned above. It has been applied to reproduce experimental data measured after a release from the industrial complex in the Odiel River and after an accidental release in the Tinto River from the gypsum piles. The model has also been applied to simulate the self-cleaning process observed in the estuary after the direct releases from the fertilizer complex were stopped. (author)

226Ra, 232Th and 40K analysis in water samples from Assiut, Egypt

International Nuclear Information System (INIS)

El-Gamal, H.; Abdel Mageed, A.I.; El-Attar, A.L; Abdel Hamid, M.

2013-01-01

The activity concentrations of 226 Ra, 232 Th and 40 K were determined in water samples, using 2”x 2” NaI(Tl) scintillation detector. Water activity ranges from 0.07 to 0.59 Bq L−1 for 226 Ra, 0.05 to 0.37 Bq L−1 for 232 Th and 3.25 to 8.72 Bq L−1 for 40 K with mean values of 2.64, 2.22 and 119.50 Bq L−1, respectively. As far as the measured gamma radionuclides is concerned, the mean annual effective doses for all analyzed samples of water are in the range of 0.02–0.08, 0.03-0.17 and 0.03-0.10 mSv yr -1 for infants, children and adults, respectively, all being lower than the reference level of the committed effective dose recommended by the WHO.

Concentration factors for 226Ra in the mullet (Mugilidae) species Mugil cephalus from the South Adriatic Sea

International Nuclear Information System (INIS)

Ivanka Antovic; Antovic, N.M.

2011-01-01

226 Ra activity concentration in the mullet (Mugilidae) species Mugil cephalus whole individuals, and some organs (gills, gastrointestinal system, fins, muscle and bones), was measured by the γ-coincidence spectrometer PRIPYAT-2M. 226 Ra transfer parameters [concentration factors (CFs)] from seawater, sediment and mud with detritus to fish tissues, and annual intake by humans consuming this fish species, have been estimated. Minimum detected radium activity concentration in whole M. cephalus individuals was found to be 0.89 ± 0.42 to 3.09 ± 0.41 Bq kg-1, with arithmetic mean of 1.65 ± 0.39 Bq kg -1 . An average concentration in muscles is found to be 2.28 ± 0.84 Bq kg -1 , in gills - 5.02 ± 1.85 Bq kg -1 , in gastrointestinal system - 12.88 ± 1.71 Bq kg -1 , and in bones - 14.72 ± 3.75 Bq kg -1 . No one fins showed radium activity above minimum detectable one. Annual intake of 226 Ra by human consumers of this fish species is estimated to provide an effective dose of 0.006 mSv year -1 . CFs for 226 Ra indicating transfer from seawater to whole individuals ranged from 8.9 to 30.9, and those indicating transfer from the sediment and mud with detritus - from 0.11 to 0.39 and from 0.08 to 0.3, respectively. The seawater to bones CFs varied from 97.9 to 197.3, to gastrointestinal system - from 59 to 178.8, to gills - from 22.5 to 68.3, to muscles - from 17 to 30.8. (author)

Distribution of "2"2"6Ra body burden of workers in an underground uranium mine in India

International Nuclear Information System (INIS)

Patnaik, R.L.; Jha, V.N.; Kumar, R.; Srivastava, V.S.; Ravi, P.M.; Tripathi, R.M.

2014-01-01

Uranium mine workers are exposed to ore dust containing uranium and its daughter products during different mining operations. These radionuclides may pose inhalation hazards to workers during the course of their occupation. The most significant among these radionuclides is "2"2"6Ra. The measurement of radium body burden of uranium mine workers is important to assess their internal exposure. For this purpose, the radon-in-breath measurement technique has been used in the present paper. Workers at the Jaduguda mine, India, associated with different categories of mining operations were monitored between 2001 and 2007. The measurement results indicate that workers - depending on mining operation category - show "2"2"6Ra body burdens ranging from 0.15 to 2.85 kBq. The maximum body burden was found for workers associated with timbering operations, with an average "2"2"6Ra body burden of 0.85 ± 0.54 kBq. Overall, the average value observed for 800 workers was 0.76 ± 0.51 kBq, which gives rise to an average effective dose of 1.67 mSv per year for inhalation and 0.21 mSv per year for ingestion. (orig.)

Natural contents of /sup 226/Ra, /sup 210/Pb, and /sup 210/Po in young human bones and teeth

Energy Technology Data Exchange (ETDEWEB)

Czegledi, P

1987-07-01

/sup 226/Ra, /sup 210/Pb, and /sup 210/Po activity concentrations were determined in tooth and bone samples of children. The children of 0 to 13 years were residents of Budapest and died from various diseases. In respect of both /sup 226/Ra and /sup 210/Pb activity concentrations, calvaria was representative for the whole skeleton. Examining the total sample, the mean activity concentrations were found to be as follows: /sup 226/Ra 1.53 +- 0.66 mBq/g Ca/sub 3/(PO/sub 4/)/sub 2/; /sup 210/Pb 4.34 +- 0.74 mBq/g Ca/sub 3/(PO/sub 4/)/sub 2/, and /sup 210/Po 3.48 +- 0.53 mBq/g Ca/sub 3/(PO/sub 4/)/sub 2/. It is shown that the burden of the skeleton is about one order of magnitude greater in the age group 1 to 13 years for all three radionuclides.

Concentration in activity of 137 Cs, 40 K, 232 Th, 226 Ra in waste deposits of the benefits of minerals in the State of Zacatecas

International Nuclear Information System (INIS)

Leal, B.; Mireles, F.; Quirino, L.; Davila, I.; Ramirez, F.

2003-01-01

The necessity to report the changes in the contained radionuclides in the terrestrial crust, or those deposited by the atomic tests around the world, becomes clear when observing the use of material of waste of those mines. With the purpose of quantifying the concentration in activity its were meet a series of waste samples in mines of the municipalities of Zacatecas, Fresnillo, Guadalupe and Veta Grande of the state of Zacatecas, Mexico. The analysis was carried out by gamma spectrometry with a HPGe detector with a resolution of 1.9 keV corresponding to an energy of 1.33 MeV calibrated in efficiency and energy by means of a certified standard multi nuclide in activity with identical geometry to that of the samples. The times of count are of 80000 seconds, with the purpose of to reduce the relative uncertainties and to define well the interest regions. The activity of 226 Ra and 232 Th is obtained through the one 214 Bi and 228 Ac respectively, the concentration was also measured in activity of the one 40 K and the 137 Cs in units of Bq kg -1 . (Author)

Development of sequential analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 and its application in mineral waters

International Nuclear Information System (INIS)

Costa Lauria, D. da.

1986-01-01

A sequential analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 in environmental samples and applied to the analysis of mineral waters is studied. Thorium isotopes are coprecipitated with lanthanium fluoride before counting in alpha spectrometer, the uranium isotopes are determined by alpha spectrometry following extraction with TOPO onto a polymenic membrane. Radium-226 is determined with the radom emanation technique. (M.J.C.) [pt

Determination of specific activities of U-238, Ra-226, Ra-228 e Th-228 in samples of mineral fertilizers with phosphorus

International Nuclear Information System (INIS)

Garcez, R.W.D.; Lopes, J.M.; Silva, A.X. da

2016-01-01

Samples were analyzed by gamma spectrometry mineral fertilizers with the HPGe detector and aid LabSOCS software for calculating the detection efficiency curve. Specific activities found for Pa-234m, Ra-226, Ra-228 and Th-228 in samples of phosphate fertilizers were 505 Bq.kg"-"1, 458 Bq.kg"-"1, 450 Bq.kg"-"1 and 394 Bq.kg"-"1, respectively. And for the NPK fertilizer samples were found average values of 390 Bq.kg"-"1, 252 Bq.kg"-"1, 280 Bq.kg"-"1 and 268 Bq.kg"-"1, respectively. (author)

Rate of sedimentation in the Yamuna river around Delhi using the sup(226)Ra-sup(210)Pb method

International Nuclear Information System (INIS)

Subramanian, V.; Sitasaward, R.; Joshi, L.U.

1985-01-01

For six sediment cores collected from Yamuna river (tributary of Ganges) around Delhi, rate of sedimentation was determined by the sup(226)Ra-sup(210)Pb method. While an average rate of 42 mm/y is obtained, there are variations core to core. A clear-cut downstream increase in the rate from 5 mm/y when the river enters Delhi, to 80 mm/y when it leaves Delhi indicates solid waste contribution from the urban areas. The sediment flux of 4000 mg/cmsup(2)/y is not balanced by the calculated rate of erosion (40 tonnes/kmsup(2)/y) in the river. Thus, much of the sediment flux is of local origin. (author)

Determination of the {sup 226}Ra, {sup 228}Ra and {sup 210}Pb concentrations in the mineral water springs from water parks of Cambuquira and Marimbeiro, Minas Gerais and assessment of the committed effective doses

Energy Technology Data Exchange (ETDEWEB)

Santos, Laíssa A.B. dos; Damatto, Sandra R., E-mail: lbonifacio@ipen.br, E-mail: damatto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-07-01

Due to the importance of human life, water quality must be controlled and a very important parameter are the limits of the natural radioactivity of the water consumed. In relation to therapeutic practices based on water intake the radionuclides {sup 210}Pb, {sup 226}Ra and {sup 228}Ra when present, are of great importance because they contribute to the internal irradiation of individuals.The study areas of the present work were the Parque das águas of Cambuquira and Marimbeiro, located in Minas Gerais. Hence, the objective of this work was to determine the {sup 226}Ra, {sup 228}Ra and {sup 210}Pb concentrations in the springs of these parks and evaluate the committed effective doses due to its consumption.The radionuclides were determined by a radiochemical procedure in four collections at different seasons of the year. The Concentrations ranged from 4 ± 1 mBq / L to 509 ± 32 mBq / L for {sup 226}Ra, from 3.7 ± 0.1 mBq / L to 631 ± 27 mBq / L for {sup 228}Ra and 5 ± 1 mBq / L to 60 ± 5 mBq / L for {sup 210}Pb. The dose for adults from 1.21 x 10{sup -01} mSv/y for {sup 226}Ra, 3.18 x 10{sup -01} mSv/y for {sup 228}Ra and for {sup 210}Pb 3.02 x 10{sup -02} mSv/y. (author)

Microdistribution and local dosimetry of 226Ra in trabecular bone of the beagle

International Nuclear Information System (INIS)

Polig, E.; Jee, W.S.; Dell, R.B.; Johnson, F.

1988-01-01

Sections of lumbar vertebral bodies of young adult beagle dogs have been analyzed autoradiographically to characterize and quantify the local distribution of 226Ra by means of a scanning microscope photometer. The animals received a single injection of 355 kBq/kg body weight and were serially sacrificed at 5 to 1381 days postinjection. Hotspot concentrations decreased from about 51 kBq/g bone at 5 days to 20 kBq/g at 1381 days postinjection. The diffuse concentration changed from 8.3 to 1.9 kBq/g. The mean 226Ra concentration in the trabecular areas scanned was initially higher and at the end of the observation period lower than the average calculated for the whole lumbar vertebral column. Density and area of, and fraction of bone activity in, hotspots virtually remained constant. With time hotspots tended to become translocated into bone volume. Mean dose rates to lining cells from both hotspots and diffuse labels decreased from about 210 mGy/d at early postinjection times to 105 mGy/d. This corresponds to 2.5 to 1.1 times the average skeletal dose rate. A discussion of the level of irradiation in terms of hit frequencies shows that osteoblasts in the initial phase of hotspot formation receive about 60 hits to their nucleus for the duration of bone formation. After about 6 months, however, the 226Ra concentration in new bone and the corresponding hit frequency appears to be low enough that interference with bone formation is unlikely. Morphometric measurements showed that abnormal bone accretion and thickening of trabeculae occurred. This was interpreted as an imbalance between bone formation and resorption. Both formation and resorption seem to be substantially lowered compared to control animals

Radiochemical determination of 210 Pb and 226Ra in petroleum sludges and scales

International Nuclear Information System (INIS)

Araujo, Andressa Arruda de

2005-01-01

The oil extraction and production, both onshore and offshore, can generate different types of residues, such as sludge, that is deposited in the water/oil separators, valves and storage tanks and scales, which form i the inner surface of ducts and equipment. Analyses already carried out through gamma spectrometry indicated the existence of high radioisotope concentration. However, radionuclides emitting low-energy gamma-rays, such as 210 Pb, are hardly detected by that technique. Consequently, there is a need to test alternative techniques to determine this and other radionuclides from the 238 U series. This work, therefore, focuses on the radiochemical determination of the concentration of 210 Pb, and 226 Ra in samples of sludge and scale from the oil processing stations of the UN-SEAL, a PETROBRAS unit responsible for the exploration and production of petroleum in Sergipe and Alagoas. The sludge and scale samples went through a preliminary process of extraction of oil, in order to separate the solid phase, where the largest fraction of the radioactivity is concentrated. After oil removal, the samples were digested using alkaline fusion as an option for dissolution. Finally, their activity concentration was determined for the samples of sludge and scales, using and alternative radiochemical method, which is based on ionic exchange. The activity concentration found for 210 Pb varied from 1,14 to 507,3 kBq kg -1 . The values for 226 Ra were higher, varying from 4,36 to 3.445 kBq kg -1 . The results for 226 Ra were then compared with the ones found for the same samples of sludge and scales using gamma spectrometry. The results of the comparison confirm the efficiency of the methodology used int hi work, that is, radiochemical determination by means of ionic exchange. (author)

The average concentrations of 226Ra and 210Pb in foodstuff cultivated in the Pocos de Caldas plateau

International Nuclear Information System (INIS)

Hollanda Vasconcellos, L.M. de.

1984-01-01

The average concentrations of 226 Ra and 210 Pb in vegetables cultivated in the Pocos de Caldas plateau, mainly potatoes, carrots, beans and corn and the estimation of the average transfer factors soil-foodstuff for both radionuclides, were performed. The total 226 Ra and 210 Pb content in the soil was determined by gamma spectrometry. The exchangeable fraction was obtained by the classical radon emanation procedure and the 210 Pb was isolated by a radiochemical procedure and determined by radiometry of its daughter 210 Bi beta emissions with a Geiger Muller Counter. (M.A.C.) [pt

Determination of 226Ra by gamma spectrometry: study of packaging vial of sample for analysis

International Nuclear Information System (INIS)

Carneiro, Andre Cavalcanti

2015-01-01

Determination of radioactivity levels of 226 Ra by gamma spectrometry in a sample is based on measurements of 214 Pb and 214 Bi, daughters of 222 Rn. Because radon is a gas, it can leak from the sample vial or accumulate on the upper empty it. If the vial has any crack, there will be loss of gas, which will cause error in determining the 226 Ra concentration. One possible cause of cracks in the vials, that houses standards and samples, is the radiolysis action in the vial material, usually a polymer. As the demand 226 Ra analysis in different matrices (geological samples, food, plants, etc.) is increasing, it was decided to study some polymer vials available on the market, to verify the feasibility to be used when is applied the analysis method using gamma spectrometry. Four types of polymer vials have been studied. The radiation doses in walls of the vials caused by natural radionuclides present in the sample were simulated using gamma irradiation. Tests, such as compressive strength test and tightness, were applied to the irradiated and non-irradiated vials. First, to verify the effect of radiolysis on the vial material and also if there was 222 Rn diffusion in their walls. These preliminary results pointed out that the acrylic vials are the best option of packaging samples for analysis. This study should be repeated in a larger number of samples for a better evaluation. (author)

Sorption study of 226Ra(II) et 238U(VI) on to peat organic matter, in mining environment

International Nuclear Information System (INIS)

Bordelet, Gabrielle

2014-01-01

The environmental footprint of former uranium mining sites is a major concern for society. In order to guarantee the protection of ecosystems and thus a minimal radiological impact on the biosphere, it is important to understand and to be able to model the phenomena controlling the migration of uranium and its decay products, specially radium ( 226 Ra) (AREVA's Envir-at-Mines project). In the environment, among solid phases which can retain 238 U(VI) and 226 Ra(II), peat is known to have relevant affinity for U(VI). Because peat is usually composed at 90% dry weight of organic matter, the aim of this study was to qualify and quantify peat organic matter affinity for 238 U(VI) and 226 Ra(II). Peat samples extracted from Les Sagnes (close to a former uranium mining site in Limousin area, France) was characterised and batch adsorption/desorption experiments were conducted. The results indicate that 226 Ra(II) adsorption onto that peat is higher than 97% for pH ≥ 4-6 (depending on the organic/mineral ratio in dry peat) corresponding to K d values about 4500 ± 500 mL/g and 238 U(VI) adsorption is higher than 80% at pH ≥ 3 with K d maximal values reaching 11000 mL/g around pH 4.5. Only a little desorption was measured after one month. An ion exchange modelling for radium adsorption onto one type of organic matter sorption site was enough to fit the experimental adsorption K d for the peat over the whole range of pH. However, uranium sorption on peat can be modelled on that organic sorption site only from pH 1 to 5. From pH 5 to 10, to explain the experimental uranium adsorption K d values (close to 1500 mL/g), uranium sorption onto mineral phases (such as smectite and iron oxide in this study) has to be considered. An operational data set is given for both 238 U(VI) and 226 Ra(II) sorption onto Les Sagnes peat. Unlike usual peat, peat from Les Sagnes contains more than 10% dry weight of mineral matter. That is why it is necessary to model sorption of those two

Radiochemical determination of {sup 210} Pb and {sup 226}Ra in petroleum sludges and scales; Determinacao radioquimica de {sup 210} Pb e {sup 226}Ra em borras e incrustacoes de petroleo

Energy Technology Data Exchange (ETDEWEB)

Araujo, Andressa Arruda de

2005-07-01

The oil extraction and production, both onshore and offshore, can generate different types of residues, such as sludge, that is deposited in the water/oil separators, valves and storage tanks and scales, which form i the inner surface of ducts and equipment. Analyses already carried out through gamma spectrometry indicated the existence of high radioisotope concentration. However, radionuclides emitting low-energy gamma-rays, such as {sup 210} Pb, are hardly detected by that technique. Consequently, there is a need to test alternative techniques to determine this and other radionuclides from the {sup 238} U series. This work, therefore, focuses on the radiochemical determination of the concentration of {sup 210}Pb, and {sup 226} Ra in samples of sludge and scale from the oil processing stations of the UN-SEAL, a PETROBRAS unit responsible for the exploration and production of petroleum in Sergipe and Alagoas. The sludge and scale samples went through a preliminary process of extraction of oil, in order to separate the solid phase, where the largest fraction of the radioactivity is concentrated. After oil removal, the samples were digested using alkaline fusion as an option for dissolution. Finally, their activity concentration was determined for the samples of sludge and scales, using and alternative radiochemical method, which is based on ionic exchange. The activity concentration found for {sup 210}Pb varied from 1,14 to 507,3 kBq kg{sup -1}. The values for {sup 226}Ra were higher, varying from 4,36 to 3.445 kBq kg{sup -1}. The results for {sup 226}Ra were then compared with the ones found for the same samples of sludge and scales using gamma spectrometry. The results of the comparison confirm the efficiency of the methodology used int hi work, that is, radiochemical determination by means of ionic exchange. (author)

Field measurements of radon exhalation and Ra-226 content in soil using the can-technique

International Nuclear Information System (INIS)

Hafez, A.F.; El-Khatib, A.M.; Moharram, B.M.; Kotb, M.A.; Abdel-Naby, A.

1991-01-01

CR-39 and LR-115 plastic nuclear track detectors in the can-technique have been employed in the field measurements of radon exhalation, Ra-226 and U-238 content in dry-soil air at numerous regions in Sudan (the Blue and White Nile and Mogran regions). Measurements gave an average radon exhalation from the soil to the atmosphere and Ra-226 content of (23.4±2.60) kBq.m -2 and (123±13.65) Bq.kg -1 respectively. A polyethylene permeable memebrane cover was used to eliminate the contribution of thoron activity inside the can. Assuming a radioactive equilibrium between the U-series, the average U-238 content in the soil was found to be (9.92±1.01) ppm. This survey may be used for uranium prospection in soil. (orig.) [de

A four phases model to simulate the dispersion of 226Ra, 238U and 232Th in an estuary affected by phosphate rock processing

International Nuclear Information System (INIS)

Perianez, R.; Abril, J.M.; Garcia-Leon, M.

1997-01-01

A numerical model to simulate the dispersion of non conservative radionuclides in tidal waters has been developed. The model includes four phases: water, suspended matter and two grain size sediment fractions. Ionic exchanges between water and the solid phases have been formulated in terms of kinetic transfer coefficients instead of distribution coefficients, because the model was developed for nonequilibrium conditions. The model simultaneously solves the shallow water hydrodynamic equations, the suspended matter dispersion equation and the four equations which give the time evolution of specific activity in each phase. The model has been applied to the Odiel river (southwest Spain), where a phosphate complex releases its wastes. It gives good results in predicting concentrations of 226 Ra, 238 U and 232 Th in water, suspended matter, distribution coefficients and Th/U mass rations. (author)

The determination of Pb-210 and Ra-226 in lake sediments and dating applications

International Nuclear Information System (INIS)

Farid, M.; El-Daoushy, A.F.

1978-04-01

The natural radioactive isotopes Pb-210 and Ra-226 were measured in two sediment cores. The Pb-210 was determined by α-detection of its grand-daughter product Po-210, using the isotope dilution technique and a surface barrier detector. Some technical improvements in the polonium extraction were achieved. The radon emanation technique was used for the determination of Ra-226. The α-activity of Rn-222 was measured using an ionization chamber with an improved filling system, which allows both low level measurements and counter calibration with standard active samples. The memory effect due to adsorption of Rn-222 on the counter walls is studied. The accumulation rates are calculated from the unsupported Pb-210. The results from one core, Gillfjaerden, are in good agreement with some studies of the reservoir effect using C-14. The data from the other core, Lake Vaexjoesjoen, indicated an irregularity in the Pb-210 profile. Results from other studies on Lake Vaexjoesjoen showed a similar propensity

Radon emanometric technique for 226Ra estimation

International Nuclear Information System (INIS)

Mandakini Maharana; Sengupta, D.; Eappen, K.P.

2010-01-01

Studies on natural background radiation show that the major contribution of radiation dose received by population is through inhalation pathway vis-a-vis contribution from radon ( 222 Rn) gas. The immediate parent of radon being radium ( 226 Ra), it is imperative that radium content is measured in the various matrices that are present in the environment. Among the various methods available for the measurement of radium, gamma spectrometry and radiochemical method are the two extensively used measurement methods. In comparison with these two methods, the radon emanometric technique, described here, is a simple and convenient method. The paper gives details of sample processing, radon bubbler, Lucas cell and the methodology used in the emanometric method. Comparison of emanometric method with gamma spectrometry has also undertaken and the results for a few soil samples are given. The results show a fairly good agreement among the two methods. (author)

Determination of 238U, 226Ra, 228Ra and 40K in grapes and wines of Valley of the Sao Francisco

International Nuclear Information System (INIS)

Silveira, Patricia Brandao da

2007-01-01

The assessment of the content of nutrients in musts and wine has been the subject of several studies due to its importance for the quality control and even for determining the geographical authenticity of a specific wine brand. Not less important is the assessment of the impact on the final product caused by the presence of contaminants in the soil. It has to be taken also into consideration that the addition of fertilizers, pesticides, and even irrigation water can increase the content of contaminants in the soil. Fertilizers, for example, may contain unwanted elements such as trace metals and radionuclides. These contaminants can affect both the quality and the commercial value of the agricultural products. The most important contaminants, as far as radioactive elements is concerned, are the members of the uranium and thorium natural series, and potassium-40, which is present in ali soils and rocks with an average concentration around 0.012% of the natural potassium. The content of uranium and of its decay products in soils can be modified by the addition of phosphate fertilizers. Although several studies have been performed aiming to assess the impact of the presence of metals and radionuclides in many agricultural products, there is no reference in the literature concerning the presence of natural radionuclides in grapes and wine. Therefore, this study was carried out with the objective of determining the content of some members of the uranium and thorium decay series (namely, 226 Ra and 228 Ra), besides 40 K, in grapes and wine produced in the Fazenda Milano, in the municipality of Petrolina - Pernambuco, in the Vale do Sao Francisco. Besides, measurements were performed for some trace metals, aiming to verify if any correlation exists between the metal and radionuclide contents. The radionuclides were determined by gamma spectrometry, using a hyper pure Germanium detector. The results for 226 Ra in samples of pulp and wine ranged from 0.60 ± 0.05 to 0.70 �

Comparative kinetics of 47Ca, 85Sr and 226Ra in the freshwater turtle, Trachemys scripta

International Nuclear Information System (INIS)

Hinton, T.G.; Whicker, F.W.; Ibrahim, S.A.; Pinder, J.E. III

1992-01-01

The kinetics of 47 Ca, 85 Sr and 226 Ra were compared in the yellow-bellied slider, a common freshwater turtle of the southeastern USA. The absorption and elimination processes were examined as a function of stable dietary Ca, season, age and sex of the animals. Turtles were gavaged with radionuclides and serial whole-body analyses were performed on the live animals for up to 480 days. Only in the juvenile age class did reduced dietary Ca cause a significant increase in 85 Sr absorption. The absorption of 85 Sr and 226 Ra in the adult male, adult female and hatchling groups was unaffected by dietary Ca. Mean absorption was greater than that which has been reported for other organisms and significantly differed among isotopes. The high absorption values were not restricted to immatures, but continued into maturity. Elimination rates were not affected by the dietary treatment, nor were isotopic differences in elimination observed. Annual mean elimination rate constants pooled among animal groups, were 0.22 ± 0.07 for 85 Sr and 0.26 ± 0.18 for 226 Ra. Retention was strongly affected by season with the greatest elimination occurring in the summer and declining to levels that were not distinguishable from zero in the winter. Elimination rate constants for hatchlings were greater than for the other age groups. (author)

Evaluation of the environmental radiological impact of Brazilian phosphogypsum and leachability of Ra-226 and Pb-210

International Nuclear Information System (INIS)

Santos, Adir Janete Godoy dos

2002-01-01

Phosphogypsum is a by-product produced by the phosphoric acid industry, it is formed by precipitation during wet sulphuric acid processing of phosphate rock. Although phosphogypsum is mainly calcium sulphate dihydrate, it contains elevated levels of impurities, which originate from the source phosphate rock used in the phosphoric acid production. Among these impurities, radionuclides from 238 U and 232 Th decay series, particularly 226 Ra, 228 Ra, 210 Pb and Th isotopes are of most concern due to their radiotoxicity. Elemental characterization of stockpiled phosphogypsum from the two main producers of phosphoric acid, Copebras Ltda and Ultrafertil S.A. named A and C respectively, located in Cubatao, was performed by instrumental neutron activation analysis (INAA). Phosphogypsum samples are enriched in rare earths elements, specifically Ce, Eu, La, Nd, Sm, Tb and Yb and the elements Ba and Th. Radiological characterization of stockpiled phosphogypsum was performed by gamma-ray spectrometry. Activity concentrations (2,3 +- 0,5) x 10 2 Bq kg -1 for 228 Ra, (8,5 +- 2,4) x 10 2 Bq kg -1 for 226 Ra and (8,4 +- 2,4) x 10 2 Bq kg -1 for 210 Pb were observed for industry A phosphogypsum. For industry C phosphogypsum, activity concentrations obtained were (1,6 +- 0,6) x 10 2 Bq kg - ''1 for 226 Ra, (3,6 +- 1,2) x 10 2 Bq kg -1 for 226 Ra and (3,4 +- 1,2) x 10 2 Bq kg -1 for 210 Pb. The radiochemical and elemental characterization of the phosphogypsum from industry A and C show that the stacks are quite homogeneous and mainly dependent upon the origin of the phosphatic rock used as raw material. The environmental radiological impact assessment of stockpiled phosphogypsum from industry C was evaluated by taking into account internal and external doses. The critical pathways considered were contamination of groundwater, emanation of radon and direct external exposure due to the radionuclides present in the phosphogypsum. The activity concentrations obtained in the monitor wells

Comparative partitioning and availability of endogenous and exogenous 226Ra in farm soils from a Brazilian high natural radioactive region

International Nuclear Information System (INIS)

Lima, V.T.; Penna Franca, E.; Fizsman, M.

1988-01-01

A sequential selective extraction was performed to determine and compare the partitioning of endogenous and exogenous Ra-226 in farm soils. The methodology allowed a good discrimination between the natural and anthropogenic origins of radium, and the exogenous form was three times more available than the endogenous one. After, a brown-bean crop, it was observed a remobilization of Ra-226 in the exchangeable, bound to carbonates and reducible fractions, and a increment of this element in the soluble phase. (author)

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

International Nuclear Information System (INIS)

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 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 226 Ra concentrations. This program uses a menu interface to minimize and simplify the tasks of system operation

Sampling errors associated with soil composites used to estimate mean Ra-226 concentrations at an UMTRA remedial-action site

International Nuclear Information System (INIS)

Gilbert, R.O.; Baker, K.R.; Nelson, R.A.; Miller, R.H.; Miller, M.L.

1987-07-01

The decision whether to take additional remedial action (removal of soil) from regions contaminated by uranium mill tailings involves collecting 20 plugs of soil from each 10-m by 10-m plot in the region and analyzing a 500-g portion of the mixed soil for 226 Ra. A soil sampling study was conducted in the windblown mill-tailings flood plain area at Shiprock, New Mexico, to evaluate whether reducing the number of soil plugs to 9 would have any appreciable impact on remedial-action decisions. The results of the Shiprock study are described and used in this paper to develop a simple model of the standard deviation of 226 Ra measurements on composite samples formed from 21 or fewer plugs. This model is used to predict as a function of the number of soil plugs per composite, the percent accuracy with which the mean 226 Ra concentration in surface soil can be estimated, and the probability of making incorrect remedial action decisions on the basis of statistical tests. 8 refs., 15 figs., 9 tabs

Measurement of the 226Ra-concentration in bottled Austrian mineral waters and table beverages

International Nuclear Information System (INIS)

Friedmann, H.; Hernegger, F.

1978-01-01

226 Ra being regarded nowadays as a toxic trace element, a systementic examination of bottled Austrian mineral waters and table beverages has been carried out. Only in one case was the maximum allowable concentration of 3.3 pCi/l, a value set up by the WHO, clearly exceeded. (orig.) [de

Ground water input to coastal salt ponds of southern Rhode Island estimated using 226Ra as a tracer.

Science.gov (United States)

Scott, M K; Moran, S B

2001-01-01

The naturally occurring radionuclide 226Ra (t1/2 = 1600 years) was used as a tracer to determine ground water input to Point Judith, Potter, Green Hill and Ninigret ponds in southern Rhode Island. Measurements of 226Ra activity were made in samples collected from salt ponds, pore waters, sediments, and local ground water wells during June-August, 1997. These results were combined with a simple box model to derive ground water input fluxes of 0.1-0.3 cm3 cm-2 d-1 (2-5 x 10(7) L d-1), which are comparable to previous estimates of ground water input to these ponds.

Development of a methodology for the detection of Ra226 in large volumes of water by gamma spectrometry; modification and validation of the method for detection and quantification of Ra226 in small volumes of water by alpha spectrometry, used by the Centro de Investigacion en Ciencias Atomicas, Nucleares y Moleculares (CICANUM, UCR)

International Nuclear Information System (INIS)

Molina Porras, Arnold

2011-01-01

The test method has been validated for quantifying the specific activity of Ra 226 in water alpha spectrometry. The CICANUM has used this method as part of the proposed harmonization of methods ARCAL (IAEA). The method is based on a first separation and preconcentration of Ra 226 by coprecipitation and subsequent MnO 2 micro precipitation as Ba (Ra) SO 4 . Samples were prepared and then was performed the counting by alpha spectrometry. A methodology of radio sampling for large volumes of water was tested in parallel, using acrylic fibers impregnated with manganese oxide (IV) to determine the amount of Ra 226 present by gamma spectrometry. Small-scale tests, have determined that the best way to prepare the fiber is the reference method found in the literature and using the oven at 60 degrees Celsius. (author) [es

Radium-226 in the population diet

International Nuclear Information System (INIS)

Toader, Maria

1993-01-01

The content of Ra-226 has been determined in samples of drinking water and food in Bucharest area in the frame of a food radioactivity monitoring program between 1987 and 1991. It has been estimated that, daily, the Bucharest population ingests 1. 4 pCi of Ra=226 or 0.89 pCi/g Ca. 1 g of Ca carries o.89 pCi Ra-226. Ra 226 was radiochemically separated by the coprecipitation method with barium chromate. The radiometric measurements were performed on an alpha measurement system with low level and high efficiency. Over the scanned period no trend of systematic increase or decrease of the Ra-226 content in the basic food of Bucharest population was observed. (author)

Search for spontaneous fission of 226Ra and systematics of the spontaneous fission, α-decay and cluster decay probabilities

International Nuclear Information System (INIS)

Mikheev, V.L.; Tret'yakova, S.P.; Golovchenko, A.N.; Timofeeva, O.V.; Hussonnois, M.; Le Naour, C.

1998-01-01

The low limit of the 226 Ra spontaneous fission half-life corresponding to T 1/2 ≥ 4 · 10 18 years is measured. The 226 Ra spontaneous fission probability proved to be about 50 times less than the value expected from the known systematics, connecting the ratios of theα-decay and spontaneous fission probabilities with the fissility parameter Z 2 /A. It is shown that the probabilities of spontaneous fission, α-decay and cluster decay can be systematized in the same way according to the difference between the decay products Coulomb energy near the scission point and decay energy Q

Simultaneous determination of RA-226, natural uranium and natural thorioum by gamma-ray spectrometry INa(Tl) in solid samples

International Nuclear Information System (INIS)

Salvador, S.; Navarro, T.; Alvarez, A.

1990-01-01

A method has been described to determine activities of Ra-226, natural uranium, and natural thorium, by gamma-ray spectrometry. The system was calibrated for efficiency by using synthetic calibrated standards. It is necessary, in the samples, to assume secular equilibrium between Ra-226 and Th-232 and its daughters nuclides, and U-238 and its immediate daughter Th-234, because the photopeaks measured are from these dsaugthers. Our results indicate that a non destructive gamma spectrometric method can ofter replace the radiochemical techniques used in measuring radiactivities in this type of samples. (Author). 9 refs

Alpha spetrometric determination of 226Ra in water samples by using ion exchanger MnO2-PAN

International Nuclear Information System (INIS)

Gardonova, V.; Dulanska, S.; Matel, L.; Bilohuscin, J.; Horvathova, B.; Sebesta, F.

2014-01-01

A method for 226 Ra preconcentration and separation from water samples using MnO 2 -PAN (polyacrylonitrile) ion absorber composite was proposed, optimized and verified. The optimization was focused on prevention of the destruction of MnO 2 -PAN composite absorber during radium elution from the column, testing of multiple use of the resin, influence of calcium concentration on radiochemical yields and application of the method for various types of water samples. Absorber was produced at Czech Technical University in Prague and now is also commercially available from Triskem International, France as MnO 2 -PAN Resin.This absorber with grain size (0.1-0.3) mm was used for 226 Ra preconcentration from various types of water samples at pH = (6.5-7.0). Radium was eluted from the ion exchanger MnO 2 -PAN with 20 mL of 6.5 mol/L HCl at flow rate of 1.5 mL/min. Samples were precipitated with Ba 2+ to form Ba(Ra)SO 4 microprecipitate for alpha spectrometry counting..The proposed method was applied to samples of natural mineral, mountain spring, drinking and natural healing waters from Slovakia, Slovenia and Czech Republic. Radium radiochemical recoveries were monitored by non-isotopic tracer 133 Ba and they were in the range of (92 - 100) %. The obtained 226 Ra activities in the analyzed samples were compared with the limit values set in Edict 528 of the Ministry of Health of the Slovak Republic in 2007 and no limit was exceeded. (authors)

Doses from {sup 222}Rn, {sup 226}Ra, and {sup 228}Ra in groundwater from Guarani aquifer, South America

Energy Technology Data Exchange (ETDEWEB)

Bonotto, D.M. E-mail: dbonotto@rc.unesp.br

2004-07-01

Groundwater samples were analysed for {sup 222}Rn, {sup 226}Ra, and {sup 228}Ra in Guarani aquifer spreading around 1 million km{sup 2} 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.

Protection of workers inside a radioactive wastes storage tunnel

International Nuclear Information System (INIS)

Leung, J.K.C.

1993-01-01

A network of tunnels which is used to store medium to low activity radioactive wastes was being reinforced structurally. Some of the radioactive wastes have to be transported from one section of the tunnel to another during the construction. The major radionuclides contained in the wastes are 226 Ra, 232 Th, 147 Pm, 60 Co and 137 Cs, hence the main radiation hazards to the workers are the external γ irradiation, internal radon exposure and internal exposure due to contaminations. The highest γ dose rate was 1000 μGy hr -1 measured at 1 cm from a lightning conductor waste containing 226 Ra. Under the unventilated condition, the highest working level for 222 Rn and 220 Rn daughters was 7.8 WL and 1 WL respectively. This paper describes the protection advices and procedures implemented to lower the radiation hazard to the workers. (1 fig., 1 tab.)

Determination of 210Pb e 226Ra in tobacco leaves cultivated in the states of Rio de Grande do Sul e Alagoas - Brazil

International Nuclear Information System (INIS)

Brandao, Y.B.; Antonio Filho, J.; Universidade Federal de Pernambuco

2005-01-01

The literature has shown that tobacco use causes damage to the health of cigarette users, manifesting itself in diseases with high mortality. Among these diseases include respiratory failure, pulmonary emphysema and lung cancer, among others. On the other hand, smoking contributes significantly to increasing the dose of natural radiation received by man, due to the presence of uranium series radionuclides, such as 226 Ra, 210 Pb and 210 Po, in relatively high concentrations in fresh tobacco leaves. The determination of these radionuclides in this matrix is of great interest, once they can be incorporated not only by the active smoker, but also by the passive smoker. The results of this study confirmed the significant presence of 226 Ra and 210 Pb in tobacco samples collected and analyzed. The average values of activity concentration found in samples from the State of Alagoas were of Bq.kg -1 0.8 to 210 Pb and 183.5 Bq.kg -1 to 226 Ra. For samples coming from the State of Rio Grande do Sul, these values were 4,0 Bq.kg -1 to 210 Pb and 161.3 Bq.kg -1 to 226 Ra

Competitive radiation-induced carcinogenesis: an analysis of data from beagle dogs exposed to 226Ra and 90Sr

International Nuclear Information System (INIS)

Momeni, M.H.

1979-01-01

The incidence of radiation-induced primary bone sarcoma and myeloproliferative diseases was studied as a function of dose rate and time in beagles that were fed diets containing 90 SrCl 2 in equilibrium with 90 Y from midgestation to 1.5 yr of age or that were administered eight intravenous injections of 226 RaCl 2 (one injection every 2 weeks for 4 months) starting at 14 months of age. Analysis of incidence of each disease in 776 beagles showed a normal probability density function with respect to time. Median incidence time and standard deviation from the mean of distribution were calculated for primary osteosarcoma at each level of administered radioactivity. The median incidence age (T) for mortality from primary osteosarcoma increased from 4.1 yr of age, 2.6 yr after final injection of radium, for beagles injected (A 0 ) with 83.6 μCi 226 Ra, to 11.5 yr of age for beagles given A 0 = 3.14 μCi 226 Ra. A similar increase in T was observed for beagles that ingested a daily diet containing 90 Sr + 90 Y, from T = 2.8 yr of age at 36 μCi 90 Sr/day to 12.6 yr at 4 μCi 90 Sr/day. Tumor yield was calculated assuming that the causes of death from competing diseases were mutually exclusive with respect to individual diseases. Incidence and cumulative incidence for each of the diseases were calculated as a function of time and maximum dose rate. These analyses were extended to beagles administered 226 Ra by a single injection or 90 Sr by injection and inhalation. Extrapolation of the observed dose effects to lower levels of administered radioactivity (comparable to maximum permissible body burden) is discussed within the framework of a competitive mortality. (author)

226Ra, 210Pb and 210Po levels in marine biota and surface coastal sediments from the Red sea, Sudan

International Nuclear Information System (INIS)

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

2003-01-01

This paper presents data on 226 Ra, 210 Pb and 210 Po activity concentration levels in multicellular marine algae, molluscs, coral as well as in surface marine sediments collected from the shallower waters of the fringing reefs area extending towards north and south (flamingo bay) of Port Sudan harbour. The analyses were performed adopting a simple time efficient method combining alpha-spectrometry, liquid scintillation and Cerenkov counting technique. generally speaking, surface sediments from this coastal region are poor in their radioactivity content in contrast to similar data reported form different coastal areas around the globe. There is surface enrichment of 210 Pb and 210 Po with respect to their progenitor 226 Ra as it is evident form the activity ratios of 210 Pb/ 226 Ra (3.03±1.79) and 210 Pb/ 226 Ra (2.23±1.56). Among marine plants and animals investigated, the green algae species, Halimeda, and coral species, Favites, show substantial concentration of radium at 8.2 Bq/kg and 21.9 Bq/kg dry weight, respectively. Similarly, the highest concentration of 210 Po was met in the favites at 38.7 Bq/kg followed by brown algae, cytoseria sp., at 32.6 Bq/kg. There is no variation seen among algal species for 210 Pb uptake, however, converse to radium and polonium, favites (coral) was found to contain the minimum concentration of lead (3.88). In most species there is preferential accumulation of polonium over its parent radium as indicated by 210 Po: 226 Ra activity ratio with cytoseria (brown algae) showing the highest value at 8.81. On the other hand, 210 Po: 220 Pb activity concentration ratio revealed that coral species favites (9.97) and the brown algae sargassum (1.85) have a greater tendency to accumulate 210 Po over 220 Pb, while in the rest of the species; this ratio is less than unity. (Author)

Toxicity of 239Pu and 226Ra in young adult beagles: risk estimate in man

International Nuclear Information System (INIS)

Miller, S.C.

1985-01-01

The overall objective of this research program is to predict the risk to humans following exposure to 239 Pu. The beagle was originally selected for this program because it is relatively long-lived and has skeletal functions and structure analogous to young adults humans, simulating that of a young adult radium dial painter or occupationally exposed person. Young adult (17 month-old) beagles from the moderately inbred colony at the University of Utah were administered one intravenous injection of 239 Pu (0.0007-2.88 μCi/kg in 238 dogs) or 226 Ra (0.007-10.4 μCi/kg in 119 dogs), and compared to appropriate age-matched control beagles. All beagles have been and are being observed clinically throughout their expected 12 to 15 year post-injection lifespan. A thorough clinical and post-mortem survey is conducted to determine causes of death or lesions at death. The clinical findings are being encoded using SNOMED terminology and entered into a computerized database. All beagles in the 226 Ra study are dead and the data are being analyzed and published. The shape of the curve for dose vs. bone tumor incidence is highly linear up to average skeletal doses of 2200 rads. In higher dose groups, the time to tumor appearance is decreased and skeletal tumors occur in almost all animals. The 226 Ra response is being compared with the 239 Pu response in beagles. This toxicity ratio will allow use of the bone tumor response in the radium dial painters to predict the toxicity of plutonium for bone tumor induction in man

Determination of {sup 210}Pb e {sup 226}Ra in tobacco leaves cultivated in the states of Rio de Grande do Sul e Alagoas - Brazil; Determinacao de {sup 210}Pb e {sup 226}Ra em folhas de tabaco cultivadas nos estados do Rio de Grande do Sul e Alagoas - Brasil

Energy Technology Data Exchange (ETDEWEB)

Brandao, Y.B. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Valentim, E.; Hazin, C.A. [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Antonio Filho, J. [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil); Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

2005-07-01

The literature has shown that tobacco use causes damage to the health of cigarette users, manifesting itself in diseases with high mortality. Among these diseases include respiratory failure, pulmonary emphysema and lung cancer, among others. On the other hand, smoking contributes significantly to increasing the dose of natural radiation received by man, due to the presence of uranium series radionuclides, such as {sup 226}Ra, {sup 210}Pb and {sup 210}Po, in relatively high concentrations in fresh tobacco leaves. The determination of these radionuclides in this matrix is of great interest, once they can be incorporated not only by the active smoker, but also by the passive smoker. The results of this study confirmed the significant presence of {sup 226}Ra and {sup 210}Pb in tobacco samples collected and analyzed. The average values of activity concentration found in samples from the State of Alagoas were of Bq.kg{sup -1} 0.8 to {sup 210}Pb and 183.5 Bq.kg{sup -1} to {sup 226}Ra. For samples coming from the State of Rio Grande do Sul, these values were 4,0 Bq.kg{sup -1} to {sup 210}Pb and 161.3 Bq.kg{sup -1} to {sup 226}Ra.

226Ra, 232Th and 40K analysis in sand samples from some beaches of Great Vitoria, Espirito Santo, Brazil: preliminary results

International Nuclear Information System (INIS)

Aquino, Reginaldo R.; Pecequilo, Brigitte R.S.

2009-01-01

The natural radioactivity in superficial beach sand samples of 7 beaches of Great Vitoria, metropolitan region of the State of Espirito Santo, southeast Brazil, was determined from the 226 Ra, 232 Th and 4 0 K contents. The assessed beaches were Manguinhos, Camburi, Praia do Canto, Curva da Jurema, Itapua, Setibao and Areia Preta. Three samples of each beach were sealed in standard 100 mL polyethylene flasks and stored in order to obtain secular equilibrium in the 238 U and 232 Th series. All samples were measured by high resolution gamma spectrometry and the spectra were analyzed with the WinnerGamma software. The 232 Th concentration was determined from the average concentrations of 228 Ac, 212 Pb and 212 Bi and the 226 Ra concentration was determined from the average concentrations of 214 Pb and 214 Bi. Preliminary results show concentrations varying from 9 Bq.kg -1 to 6035 Bq.kg -1 for 232 Th, from 4 Bq.kg -1 to 575 Bq.kg -1 for 226 Ra and from 13 Bq.kg -1 to 142 Bq.kg -1 for 40 K. Areia Preta beach shows the highest values for 232 Th, while the highest value for 226 Ra was observed for Camburi beach. High values of 40 K were observed for Curva da Jurema beach. (author)

Environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks, New Jersey Coastal Plain, USA: migration to the water table.

Science.gov (United States)

Szabo, Zoltan; Jacobsen, Eric; Kraemer, Thomas F; Parsa, Bahman

2010-01-01

Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra ((226)Ra plus (228)Ra) concentrations (maximum, 1.54 Bq L(-1)) exceeded the 0.185 Bq L(-1) Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from leachfields, combined Ra concentrations were low (commonly 5.3, indicating sequestration; when pH was septic-tank effluents (maximum, 0.243 Bq L(-1))), indicating Ra mobilization from leachfield sediments. Confidence in quantification of Ra mass balance was reduced by study design limitations, including synoptic sampling of effluents and ground waters, and large uncertainties associated with analytical methods. The trend of Ra mobilization in acidic environments does match observations from regional water-quality assessments.

Influences of liming on the soil-plant transfer of Ra-226 from acid soils field experiments

International Nuclear Information System (INIS)

Eriksson, Aa.

1985-01-01

The effects of liming of the plough layer in the early sixties on the contents of exchangeable Ca and Ra-226 in soil, and on the contents of Ca and Ra in the crops in the early eighties have been investigated. It was found that liming, while increasing the amounts of Ca, reduced the amounts of Ra and the ratio Ra/Ca exchangeable in soil. Liming influenced the plant upake of Ra more for the vegetative than for the generative parts of the grain crops. However, the reduction of the Ra/Ca-ratio in the former was not as effective as in the soil. In the grain it was uncertain. The difference can, however, be explained by the fact that the minerals in straw and grain are more or less taken from different layers of the soil profile. The crop is more dependant on the plough layer during the early development than later, when grain is developed

The transport characteristics of {sup 238}U, {sup 232}Th, {sup 226}Ra, and {sup 40}K in the production cycle of phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Chung, Kun Ho; Kang, Mun Ja [Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., 238U and 226Ra), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, 238U, 232Th, 226Ra, and 40K levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of 238U, 232Th, 226Ra, and 40K. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. The concentration ratios of 226Ra and 238U in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was 40K, and the median 40K activity was 8.972 Bq·g−1 and 1.496 Bq·g−1, respectively. For the 238U series, the activity of 238U and 226Ra was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Although the activity of 40K in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of 226Ra and 238U in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing.

Studies on sup(226) Ra and sup(210) Pb activities and the concentration factors of sup(226) Ra in the surface organic layers of the estuarine sediments of Mindola and Purna rivers in India

Digital Repository Service at National Institute of Oceanography (India)

Joshi, L.U.; Zingde, M.D.; Desai, B.N.

., to the sediment floor The activities of sup(226) Ra are found to vary from 0.1 to 0.5 pCi/g, while sup(210) Pb activities lie in the range of 3 to 8 pCi/g These activities find their way into the organisms present in sea water and then into fish which is finally...

Waste Management During RA Reactor Decommissioning

International Nuclear Information System (INIS)

Markovic, M.; Avramovic, I.

2008-01-01

The objective of radioactive waste management during the RA reactor decommissioning is to deal with radioactive waste in a manner that protects human health and the environment now and in the future. The estimation of waste quantities to be expected during decommissioning is a very important step in the initial planning. (author)

Assessment of annual effective dose from 238U and 226Ra due to consumption of foodstuffs by inhabitants of Tehran city (IR)

International Nuclear Information System (INIS)

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

2006-01-01

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

Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples

International Nuclear Information System (INIS)

Salvador, S.; Navarro, T.; Alvarez, A.

1991-01-01

A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs

Radiation-Induced Neoplasms in Beagles after Administrations of {sup 90}Sr and {sup 226}Ra

Energy Technology Data Exchange (ETDEWEB)

Goldman, M.; Dungworth, D. L.; Bulgin, M. S.; Rosenblatt, L. S.; Richards, W. P.C.; Bustad, L. K. [Radiobiology Laboratory and Department of Veterinary Pathology, University of California, Davis, CA (United States)

1969-11-15

The comparative carcinogenic efficiency of two bone-seeking radionuclides is under study in a colony of several hundred beagles. The toxicity of internally deposited alpha emitters ({sup 226}Ra and its daughters) and of beta irradiation ({sup 90}Sr) at comparable dosage rates indicates marked differences in site of appearance and mode of action in litters studied up to 7 years of age. Radiation carcinogenesis in beagles exposed to {sup 90}Sr daily from midgestation to adulthood (1.5 yr) is at present confined to dogs fed 4 {mu}Ci {sup 90}Sr/d or higher. The 20 cases constitute a spectrum of myeloproliferative disorders characterized by terminal anaemias, and ranging from myeloid metaplasia to granulocytic leukaemia. Continuous high-level {sup 90}Sr irradiation to bone and marrow from early life onward causes a thickened hypocellular bone ('pachyostosis'), some instances of myelofibrosis, and persistent mild leukopenia on which the final spectrum of terminal disoideis is superimposed. In contrast, up to 100 {mu}Cl {sup 226}Ra given intravenously (8 equally spaced injections at 14 to 18 months of age) to young adults is not a potent marrow cell carcinogen. The higher LET, shorter-range alpha particles are efficient in inducing bone cancers (14 cases) and skeletal lesions similar to those documented in watch-dial luminizers exposed to {sup 226}Ra in the early 1900's. The incidence of haematopoietic and skeletal neoplasms observed is dose-rate related, and the morphologic characteristics have several analogues in human cancer. The use of identically treated litters rather than individuals affords additional opportunity to study possible familial factors in the distribution of the neoplasms. Pathogenic evaluation at this juncture strongly indicates that continued bone and marrow irradiation in early life is more likely to induce haematopoietic neoplasms than is skeletal irradiation starting in young adulthood, which induces osseous neoplasms. (author)

Evaluation of Ra-226, Th-232 and K-40 activities concentrations and radium equivalent index in several Brazilian economic wall paints

International Nuclear Information System (INIS)

Fonseca, Leandro M.; Pecequilo, Brigitte R.S.

2015-01-01

The titanium dioxide used as the white pigment in paints is produced from the processing of ilmenite minerals. As monazite, the main ilmenite radioactive contaminant, contains 1 to 20% thorium dioxide and also some uranium traces, so, eventually, wall paints can contain radioactivity. Activity concentrations of the naturally occurring radionuclides 226 Ra, 232 Th and 40 K were determined in 15 Brazilian economic wall paints samples, by high resolution gamma-ray spectrometry. The activities concentrations in the studied samples ranged from 1.3 ± 0.2 Bq/kg to 23.4 ± 0.7 Bq/kg for 226 Ra; from 2.5 ± 0.4 Bq/kg to 45.8 ± 1.5 Bq/kg for 232 Th and from 5.8 ± 2.1 Bq/kg to 157 ± 22 Bq/kg for 40 K. The radium equivalent index, calculated from the 226 Ra, 232 Th and 40 K concentrations, varied from 1.30 Bq/kg up to 95.9 Bq/kg, below the value of 370 Bq/kg recommended by OECD for a safety use in residential building applications. (author)

Geochemical approach of the salinization mechanisms of coastal aquifers - 14C - 226Ra chronologies

International Nuclear Information System (INIS)

Barbecot, F.

1999-11-01

Through time, coastal aquifers which constitute a great part of available fresh water resources from sedimentary basins in France, were submitted to changes in hydraulic gradients and hydrodynamic properties mainly due to discharge/recharge phases in response to sea level variations and/or anthropic forcing. Performed in the framework of the European program PALAEAUX ('Management of coastal aquifers in Europe, paleo-waters and natural controls'), this work aimed to understand the salinization process originating from the recharge/discharge conditions and recognized in three study aquifers: the calcareous Dogger aquifers along the Channel (Caen area), and the Atlantic coast (Marais Poitevin), and the Astian sandy aquifer (Cap d'Agde). Besides the conventional hydrogeological and hydrochemical methods, the main tools used are those of isotope geochemistry. For the three sites, the modern, fresh groundwaters are marked by the anthropisation of the recharge area. The evolution of isotopic signatures along a flow path depending on the mineralogy of the aquifer matrix, is linked to water-rock interactions such as cation exchange, and equilibrium with aluminosilicates. For the three study sites, the modern fresh groundwaters are marked by the anthropisation of the recharge area. The evolution of isotopic signatures along a flow path depending on the mineralogy of the aquifer matrix, is linked to water-rock interactions such as cation exchange, and equilibrium with aluminosilicates. Residence times of these fresh groundwater are from Present (Atlantic site) up to the 14 C detection limit (Channel site). Groundwater of the Astian aquifer belongs to Holocene, as determined by both 14 C and 226 Ra. From Present to 3 ka, 14 C and 226 Ra ages are coherent. Beyond, the discrepancy observed can be associated to the under-estimation of in- situ 226 Ra production, but more likely, to the 'buffer' effect of the matrix with respect to the 14 C isotopic equilibration. The salty waters

Root uptake of exogenous Ra226 by three edible vegetables grown in farm soils from the vicinity of the first Brasilian Uranium Mine and Mill

International Nuclear Information System (INIS)

Teixeira, V.S.; Franca, E.P.

1988-01-01

The purpose of this work was to evaluate the uptake of exogenous 226 Ra by carrot, brow-bean and cabbage. Greenhouse experiments were carried out with farm soils collected near the first Brazilian Uranium Mine and Mill and contamin ted with 226 Ra solution. After the maturity, the plants were harvested, ashed and this nuclide was analysed by gamma spectrometry. Among the edible parts, 226 Ra content decreased in the following order: cabbage > brown-bean > carrot. Soil-to-plant transfer coeficients were of the order of 10 -2 , values of 10 to 100 times greater than those observed in the region. The results emphasize the importance of irrigation water as a contamination pathway of human groups in the area. (Author) [pt

On hygiene standardization of combined environmental factors (on the basis of data on rat death in three generations after injection of 226Ra+herbicide TMTD)

International Nuclear Information System (INIS)

Mukhin, I.E.; Borovinova, N.M.; Svatkov, V.I.

1978-01-01

The toxic effect of a binary mixture of 226 Ra and TMTD herbicide has been determined by mathematical treatment of the results. The results of death in three generators of white rats of no breed, which had been subjected to chronical poisoning with the binary mixture of 226 Ra and TMTD herbicide, were investigated. A coefficient of the combined effect was calculated. The advantage in determining the error of this coefficient was given to logarythmic calculations and not to differentiation. This permits a detection of antilogarythmic and coalitive changes in the generative functions of rats after a combined effect of 226 Ra+TMTD mixture. The indices of rat generations, which have been affected by the combined effect of both substances introduced into the rats, are presented

Measuring 137Cs, 40K and decay products of 226Ra and 232Th in samples of different nature by a multidetector spectrometer

International Nuclear Information System (INIS)

Antovic, N.M.; Popovic, V.; Vukotic, P.

2011-01-01

A coincidence method for measuring 137 Cs, 40 K, 226 Ra and 232 Th decay products activity in soil, vegetation and fish samples, was applied to the six-crystal gamma-coincidence spectrometer PRIPYAT-2M. In this way, some problems appeared in simultaneous measurement of 137 Cs, 226 Ra and 232 Th by NaI(Tl) detectors and the PRIPYAT-2M spectrometer were solved. The obtained results were agreeable with the HPGe spectrometer ones. (author)

Concentrations of 226Ra and 210Pb in agricultural products surrounding the first brazilian mine and mill in Pocos de Caldas, MG

International Nuclear Information System (INIS)

Vasconcellos, L.M.H.; Amaral, E.C.S.; Vianna, E.C.M.

1989-01-01

As a complement to the pre-operational environmental monitoring program of the Brazilian first uranium mine and mill, a survey of 226 Ra and 210 Pb in agriculture products, and in the corresponding soils, were carried out in the Pocos de Caldas Plateau. The survey intended to determine site specific transfer factors, in order to better estimate radiation doses on the population. Resulting from the plant operation. In local soils, 226 Ra and 210 Pb have similar concentrations. The average contents are comparable to the values found in areas of normal radioactivity, but the maximum values are higher by one order of magnitude. In the vegetables analyzed (beans, carrot, corn and potato), 226 Ra concentrations are slightly higher than those of 210 Pb, and the maximum values are also one order of magnitude greater than in normal regions. For both radionuclides, the average soil-to-plant transfer factors are of the order of 10 -3 and 10 -2 , when related to total and to exchangeable contents in soils, respectively. These results led to the conclusion that 226 Ra and 210 Pb have similar importance, concerning the population exposure via the foodstuff ingestion pathway. Therefore, it was recommended to carry on routine monitoring program for both radionuclides in the main agriculture crops. However, the naturally elevated radionuclide concentrations, in some local vegetables, will decrease the sensitivity for detecting small increments resulting from the plant operation. (author) [pt

22 CFR 226.14 - Special award conditions.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Special award conditions. 226.14 Section 226.14 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ADMINISTRATION OF ASSISTANCE AWARDS TO U.S. NON-GOVERNMENTAL ORGANIZATIONS Pre-award Requirements § 226.14 Special award conditions. If an applicant or...

Radium-226 on drinking water of Camaguey, Cuba; Radio-226 en agua potable de Camaguey, Cuba

Energy Technology Data Exchange (ETDEWEB)

Montalvan Estrada, Adelmo; Brigido Flores, Osvaldo; Barrera Caballero, Aldo [Centro de Atencion a la Actividad Nuclear, Camaguey (Cuba)]. E-mail: sean@caonao.cmw.inf.cu; Escalante, Alexander [Centro Provincial de Higiene y Epidemiologia, Camaguey (Cuba)

2001-07-01

The specific activity of Ra-226 in drinking water of Camaguey city, Cuba, was measured using the emanometric method. The specific activity of Ra-226 in drinking water ranged from 15 {+-} 5 mBq.l{sup -1} to 39 {+-}12 mBq.l{sup -1}. The mean specific activity of Ra-226 was found to be 27 {+-} 8 mBq.l{sup -1}. No seasonal variation was found. Water samples were collected from the two main sources of drinking water: private wells and governmental water supply system, being the mean specific activities of Ra-226: 25 {+-} 7 mBq.l{sup -1} and 31 {+-} 9 mBq.l{sup -1} , respectively. Based upon measured concentrations the age-dependent associated effective doses due to the ingestion of Ra-226, as a consequence of direct consumption of drinking water, have been calculated. For the age interval 1 year to 5 years, the average effective dose was 6,2 {mu}Sv.y{sup -1}, and for adults the average effective dose was 5,2 {mu}Sv.y{sup -1}. (author)

Distribution of {sup 226}Ra-{sup 210}Pb-{sup 210}Po in marine biota and surface sediments of the Red Sea, Sudan

Energy Technology Data Exchange (ETDEWEB)

Sirelkhatim, D.A. [Sudan Atomic Energy Commission, Environmental Monitoring, Khartoum, P.O. Box 3001 (Sudan)], E-mail: rifaatk@hotmail.com; Sam, A.K.; Hassona, R.K. [Sudan Atomic Energy Commission, Environmental Monitoring, Khartoum, P.O. Box 3001 (Sudan)

2008-12-15

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

Study of the specific activity concentrations of 40K, 226Ra, 228Ra and 232Th in vegetables and their respective covering tissues (peels)

International Nuclear Information System (INIS)

Lopes, J.M.; Garcêz, R.W.D.; Silva, A.X.

2017-01-01

This work presents an analysis of specific concentrations of 40 K, 226 Ra, 228 Ra and 232 Th in some vegetables that are part of the diet of the population of the state of Rio de Janeiro. Furthermore, was analyzed the concentrations of radionuclides in the same coating tissue that compose the vegetables. It can notice an increase of the specific concentration of 40 K in the peels of vegetables that have little or no contact with the ground. Among the samples examined, only the pumpkin showed measurable amount of 137 Cs both saves and in the skin. (author)

Evaluation of the Ra-226 activity in public-consumption water in the Huarangal Valley using the radiochemical precipitation method as Ba(Ra)SO4

International Nuclear Information System (INIS)

Ysla C, M.A.

1999-01-01

Five radiochemical methods for Ra-226 determination in public-consumption river waters are developed in this work. Quantification of this radionuclide was conducted through high-resolution gamma spectrometry. These five methods are based on the precipitation of Ra-226 as Ba(Ra)SO 4 . The second of these methods has been considered the best due to its low cost, high radiochemical performance (83,53%) and lowest standard deviation (7,97). Using the second method (standardized method) it was determined that the activity present in a 32 L sample of water is 0,1526 Bq/L. Assuming that each person in Huarangal Valley consumes an average of 2 liters of water a day, we can estimate that this person consumes 111,398 Bq anally, a very low percentage compared to the limit activity reported in other parts of the world. Physicochemical analysis were also conducted in waters of the Chillon river; the results obtained are within the permissible limits established by the World Health Organization, the Institute of Technological, Industrial and Technical Regulation Research (ITINTEC), and the law for Waters of the Ministry of Agriculture. One can conclude, from the physicochemical analysis that have been conducted, that the waters of the Chillon river are fit for public consumption and do not present specific radio-sanitary risks for people living in the Huarangal valley

Radio-ecological tests on the 226Ra content from the viewpoint of the mans environment protection

International Nuclear Information System (INIS)

Kwapulinski, J.; Kwapulinska, G.

1974-01-01

The industrial environment pollution with 226 Ra has been dealt with. Records of radium in water, in the dust collected on electro-filters, and in the monthly precipitation and specimens of faller dust have been suggested for such environments. Monitoring of all kinds of power coal for radium content has found necessary

Comparative kinetics of sup 47 Ca, sup 85 Sr and sup 226 Ra in the freshwater turtle, Trachemys scripta

Energy Technology Data Exchange (ETDEWEB)

Hinton, T.G. (Savannah River Ecology Lab., Aiken, SC (United States) Colorado State Univ., Fort Collins, CO (United States)); Whicker, F.W.; Ibrahim, S.A. (Colorado State Univ., Fort Collins, CO (United States)); Pinder, J.E. III (Savannah River Ecology Lab., Aiken, SC (United States))

1992-01-01

The kinetics of {sup 47}Ca, {sup 85}Sr and {sup 226}Ra were compared in the yellow-bellied slider, a common freshwater turtle of the southeastern USA. The absorption and elimination processes were examined as a function of stable dietary Ca, season, age and sex of the animals. Turtles were gavaged with radionuclides and serial whole-body analyses were performed on the live animals for up to 480 days. Only in the juvenile age class did reduced dietary Ca cause a significant increase in {sup 85}Sr absorption. The absorption of {sup 85}Sr and {sup 226}Ra in the adult male, adult female and hatchling groups was unaffected by dietary Ca. Mean absorption was greater than that which has been reported for other organisms and significantly differed among isotopes. The high absorption values were not restricted to immatures, but continued into maturity. Elimination rates were not affected by the dietary treatment, nor were isotopic differences in elimination observed. Annual mean elimination rate constants pooled among animal groups, were 0.22 {+-} 0.07 for {sup 85}Sr and 0.26 {+-} 0.18 for {sup 226}Ra. Retention was strongly affected by season with the greatest elimination occurring in the summer and declining to levels that were not distinguishable from zero in the winter. Elimination rate constants for hatchlings were greater than for the other age groups. (author).

Transfer factors of 226Ra, 210Pb and 210Po from NORM-contaminated oil field soil to some Atriplex species, Alfalfa and Bermuda grass

International Nuclear Information System (INIS)

Al-Masria, M.S.; Mukalallati, H.; Al-Hamwi, A.

2014-01-01

Transfer factors of 226 Ra, 210 Pb and 210 Po from soil contaminated with naturally occurring radioactive materials (NORM) in oil fields to some grazing plants were determined using pot experiments. Contaminated soil was collected from a dry surface evaporation pit from a Syrian oil field in the Der Ezzor area. Five types of plants (Atriplex halimus L., Atriplex canescens, Atriplex Leucoclada Bioss, Alfalfa and Bermuda grass) were grown and harvested three times over two years. The results show that the mean transfer factors of 226 Ra from the contaminated soil to the studied plant species were 1.6 x 10 -3 for Atriplex halimus L., 2.1 x 10 -3 for Atriplex canescens, 2.5 x 10 -3 for Atriplex Leucoclada Bioss, 8.2 x 10 -3 for Bermuda grass, and the highest value was 1.7 x 10 -2 for Alfalfa. Transfer factors of 210 Pb and 210 Po were higher than 226 Ra TFs by one order of magnitude and reached 7 x 10 -3 , 1.1 x 10 -2 , 1.2 x 10 -2 , 3.2 x 10 -2 and 2.5 x 10 -2 for Atriplex halimus, Atriplex canescens, Atriplex Leucoclada Bioss, Bermuda grass and Alfalfa, respectively. The results can be considered as base values for transfer factors of 226 Ra, 210 Pb and 210 Po in semiarid regions. (authors)

Pre-operational monitoring program of Ra-226 in biological material in uranium mining and milling areas

International Nuclear Information System (INIS)

Souza Pereira, Wagner de; Azevedo Py Junior, Delcy de; Kelecom, Alphonse; Iatesta, Antonio

2008-01-01

The environmental licensing processes of 'Santa Quiteria' uranium mining and milling unit are being carried out nowadays. The pre-operational radiological environmental monitoring program is part of those processes, which has the objective of determining the background for further comparisons and evaluation of radiological environmental impact of the operation unit. This work shows the results of Ra-226 determination in the most consumed farm products of the region, which are black beans, corn and milk. These data are compared with data available in the literature. Measurement results of Ra-226 in black beans vary from 3.3 x 10 -2 Bq/Kg to 9.1 x 10 -2 Bq/Kg; in corn, the results vary from 8.0 x 10 -3 Bq/Kg to 4.6 x 10 -2 Bq/Kg; in milk the results vary from 1.0 x 10 -3 Bq/Kg to 7.0 x 10 -3 Bq/Kg that represents the smallest variation range. All of these results are in good agreement with literature reported data. (author)

Determination of Ra-226, Ra-228 and K-40 specific activities in samples of mineral fertilizer marketed in the Rio de Janeiro City

International Nuclear Information System (INIS)

Garcez, R. W. D.; Marques L, J.; Da Silva, A. X.

2017-10-01

The use a fertilizers ia a common practice in agriculture and several samples have radionuclides in their composition, this content is natural but some samples may have high concentrations of these radionuclides and this represent a potential radiological risk for plants, animals and water. Therefore the radiometric analyses these compounds is important and the main aim of this paper is to determine the specific concentration of K-40, Ra-226 and Ra-228 in fertilizer samples available in market of Rio de Janeiro city and discussing the impacts to agricultural soils caused by this practice. The analyzed fertilizer samples are of four types: nitrogen, potash, phosphate and NPK, they were analyzed using gamma spectroscopy with a Hp-Ge detector and with the LabSOCS software for the calculation of the efficiency curve. The specific activities of Ra-226 ranged from 1.48 Bq/kg to 597 Bq/kg, Ra-228 ranged from 2.66 Bq/kg to 832 Bq/kg and K-40 ranged from 16 Bq/kg to 13941 Bq/kg. All samples, except two nitrogen fertilizer samples, presented the absorbed dose rate in air at 1 m above the ground level higher than the estimated average global terrestrial radiation of 51 n Gy/h and the phosphate fertilizer samples presented the highest average absorbed dose rate of 532.5 n Gy/h, which indicates a greater potential of environmental contamination. But considering a dilution (1:1000) g of fertilizer in soil was found an average increase of 0.36 μSv/y at the annual outdoor effective dose while the annual average for the soil is of 63 μSv/y, so the risk to human health is minimum. (Author)

A computer-controlled system for rapid soil analysis of 226Ra

International Nuclear Information System (INIS)

Doane, R.W.; Berven, B.A.; Blair, M.S.

1984-01-01

A computer-controlled multichannel analysis system has been developed by the Radiological Survey Activities (RASA) Group at Oak Ridge National Laboratory (ORNL) for the Department of Energy (DOE) in support of the DOE's remedial action programs. The purpose of this system is to provide a rapid estimate of the 226 Ra concentration in soil samples using a 6 x 9 inch NaI(T1) crystal containing a 3.25 inch deep by 3.5 inch diameter well. This gamma detection system is controlled by a minicomputer with a dual floppy disk storage medium, line printer, and optional X-Y plotter. A two-chip interface was also designed at ORNL which handles all control signals generated from the computer keyboard. These computer-generated control signals are processed in machine language for rapid data transfer and BASIC language is used for data processing. The computer system is a Commodore Business Machines (CBM) Model 8032 personal computer with CBM peripherals. Control and data signals are utilized via the parallel user's port to the interface unit. The analog-to-digital converter (ADC) is controlled in machine language, bootstrapped to high memory, and is addressed through the BASIC program. The BASIC program is designed to be ''user friendly'' and provides the operator with several modes of operation such as background and analysis acquisition. Any number of energy regions-of-interest (ROI) may be analyzed with automatic background substraction. Also employed in the BASIC program are the 226 Ra algorithms which utilize linear and polynomial regression equations for data conversion and look-up tables for radon equilibrating coefficients. The optional X-Y plotter may be used with two- or three-dimensional curve programs to enhance data analysis and presentation. A description of the system is presented and typical applications are discussed

Determination of Radium 226 in mexican phosphate fertilizers and gypsum by gamma spectrometry.; Determinacion de Radio 226 en fertilizantes fosfatados y en yeso mediante espectrometria gamma.

Energy Technology Data Exchange (ETDEWEB)

Godinez A, M C

1996-12-31

The {sup 226} Ra isotope was determined in 17, 20 and 46% m/m phosphate fertilizers and gypsum. The samples of the fertilizers were dissolved in 10% v/v nitric acid solutions. The barium sulphate method was used for the precipitation of {sup 226} Ra. On the other hand, alkaline fusion method was used to separate the {sup 226} Ra from gypsum. The results indicated that {sup 226} Ra was present in the phosphate fertilizers and gypsum. The {sup 226} Ra concentrations present in these materials were between 10 {sup -4} - 10 {sup -5} {mu}g g{sup -1}. (Author).

Computer-controlled system for rapid soil analysis of 226Ra

International Nuclear Information System (INIS)

Doane, R.W.; Berven, B.A.; Blair, M.S.

1984-01-01

A computer-controlled multichannel analysis system has been developed by the Radiological Survey Activities Group at Oak Ridge National Laboratory (ORNL) for the Department of Energy (DOE) in support of the DOE's remedial action programs. The purpose of this system is to provide a rapid estimate of the 226 Ra concentration in soil samples using a 6 x 9-in. NaI(Tl) crystal containing a 3.25-in. deep by 3.5-in. diameter well. This gamma detection system is controlled by a mini-computer with a dual floppy disk storage medium. A two-chip interface was also designed at ORNL which handles all control signals generated from the computer keyboard. These computer-generated control signals are processed in machine language for rapid data transfer and BASIC language is used for data processing

Removal of radium-226 from uranium mining effluents

International Nuclear Information System (INIS)

Averill, D.W.; Moffett, D.; Webber, R.T.; Whittle, L.; Wood, J.A.

1984-12-01

Uranium mining and milling operations usually generate large quantities of solid and liquid waste materials. A slurry, consisting of waste rock and chemical solutions from the milling operation, is discharged to impoundment areas (tailings basins). Most of the radioactive material dissolved in tailings slurries is precipitated by the addition of lime and limestone prior to discharge from the mill. However, the activity of one radioisotope, radium-226, remains relatively high in the tailings basin effluents. In Canada, radium-226 is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate barium-radium sulphate [(Ba,Ra)SO 4 ]. Although dissolved radium-226 activities are generally reduced effectively, the process is considered to have two undesirable characteristics: the first related to suspended radium-226 in the effluents and the second to ultimate disposal of the (Ba,Ra)SO 4 sludge. A government-industry mining task force established a radioactivity sub-group in 1974 to assist in the development of effluent guidelines and regulations for the uranium mining industry (Radioactivity Sub-group, 1974). The investigation of more effective removal methods was recommended, including the development of mechanical treatment systems as alternatives to settling ponds. Environment Canada's Wastewater Technology Centre (WTC) initiated a bench scale study in March, 1976 which was designed to assess the feasibility of using precipitation, coagulation, flocculation and sedimentation for the removal of radium-226. In 1977, the study was accelerated with financial assistance from the Atomic Energy Control Board. The results were favourable, with improved radium removals obtained in bench scale batch tests using barium chloride as the precipitant and either alum or ferric chloride as the coagulant. A more comprehensive bench scale and pilot scale process development and demonstration program was formulated. The results of the joint study

Estimating calibration equations for predicting Ra-226 soil concentrations using RTRAK in-situ detectors at the Ambrosia Lake, New Mexico, Umtra site

International Nuclear Information System (INIS)

Gilbert, R. O.; Meyer, H. R.; Miller, M. L.; Begley, C.

1988-06-01

This report describes a field study conducted at the Ambrosia Lake, New Mexico, UMTRA site to obtain data for calibrating the RTRAK Sodium Iodide (NaI) detectors for estimating concentrations of Ra-226 in surface soil. The statistical analyses indicate that the data are useful for estimating the calibration equations. Several statistical models are used to evaluate which model is best as a basis for the calibration equations. A procedure is provided for using the estimated calibration equations and extensive RTRAK measurements to estimate the average Ra-226 concentration on 100-m 2 land areas to determine whether additional remedial action is needed. The UMTRA Project office proposes to use the RTRAK for cleanup verification of surface Ra-226 contamination. The system enables 100% coverage of areas having undergone remedial action. The sensitivity of the system enables verification at less than 5 pCi/g averaged over 100 m 2 , as specified by the Environmental Protection Agency (EPA) standards (40 CFR Part 192). This analysis demonstrates RTRAK's ability to meet reasonable standards of statistical accuracy, using commonly accepted procedures. 5 refs., 8 figs., 1 tab

Concentration in activity of {sup 137} Cs, {sup 40} K, {sup 232} Th, {sup 226} Ra in waste deposits of the benefits of minerals in the State of Zacatecas; Concentracion en actividad de {sup 137} Cs, {sup 40} K, {sup 232} Th, {sup 226} Ra en depositos de desecho del beneficio de minerales en el Estado de Zacatecas

Energy Technology Data Exchange (ETDEWEB)

Leal, B.; Mireles, F.; Quirino, L.; Davila, I.; Ramirez, F. [UAZ, A.P. 579C, 98068 Zacatecas (Mexico)

2003-07-01

The necessity to report the changes in the contained radionuclides in the terrestrial crust, or those deposited by the atomic tests around the world, becomes clear when observing the use of material of waste of those mines. With the purpose of quantifying the concentration in activity its were meet a series of waste samples in mines of the municipalities of Zacatecas, Fresnillo, Guadalupe and Veta Grande of the state of Zacatecas, Mexico. The analysis was carried out by gamma spectrometry with a HPGe detector with a resolution of 1.9 keV corresponding to an energy of 1.33 MeV calibrated in efficiency and energy by means of a certified standard multi nuclide in activity with identical geometry to that of the samples. The times of count are of 80000 seconds, with the purpose of to reduce the relative uncertainties and to define well the interest regions. The activity of {sup 226} Ra and {sup 232} Th is obtained through the one {sup 214} Bi and {sup 228} Ac respectively, the concentration was also measured in activity of the one {sup 40} K and the {sup 137} Cs in units of Bq kg{sup -1}. (Author)

The transport characteristics of "2"3"8U, "2"3"2Th, "2"2"6Ra, and "4"0K in the production cycle of phosphate rock

International Nuclear Information System (INIS)

Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Chung, Kun Ho; Kang, Mun Ja

2017-01-01

Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., 238U and 226Ra), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, 238U, 232Th, 226Ra, and 40K levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of 238U, 232Th, 226Ra, and 40K. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. The concentration ratios of 226Ra and 238U in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was 40K, and the median 40K activity was 8.972 Bq·g−1 and 1.496 Bq·g−1, respectively. For the 238U series, the activity of 238U and 226Ra was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Although the activity of 40K in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of 226Ra and 238U in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing

Assessment of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb concentration in mineral waters from Parque das Águas de Lambari and Contendas, MG and evaluation of the committed effective doses

Energy Technology Data Exchange (ETDEWEB)

Wakasugi, Denise S.M.; Damatto, Sandra R., E-mail: denise.sanny@usp.br, E-mail: damatto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-11-01

The exploration of several Brazilian hydromineral resorts, that have springs of radioactive mineral water consumed by the population support the relevance of the present work. This study is being developed in the IPEN with the aid of the responsible for Parque das Águas de Lambari and Contendas. Thereby, this work aims to determine the activity concentrations of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb to verify the influence of seasonality in these water parks springs. Thereunto, gross alpha and beta measurements were used after radiochemical separation for these radionuclides determination and measurement in a low background proportional detector. The results showed that Parque das Águas de Lambari presented highest concentration values when compared with Contendas. In Parque das Águas de Contendas , the highest concentration values were 77 ± 5 mBq/L and 129 ± 5 mBq/L for {sup 226}Ra for Gasosa II springs and {sup 228}Ra for Gasosa I spring, respectively, which correspond to the spring season; for {sup 210}Pb, 27 ± 2 mBq/L for Magnesiana spring in the same season. In Parque das Águas de Lambari, the highest concentration values for {sup 226}Ra was 177 ± 2 mBq/L and for {sup 210}Pb, 36 ± 2 mBq/L, both in the Magnesiana spring, for the summer season and 135 ± 5 mBq/L for {sup 228}Ra, in Magnesiana spring, for the spring season. The data were analyzed through descriptive and correlational statistical techniques. Therefore, it was possible to evaluate the committed effective doses due to the consumption of these waters and to assess the radiological risk for the radionuclides studied. (author)

Long-term effects of an intracavitary treatment with californium-252 on normal tissue. [Swine, /sup 226/Ra

Energy Technology Data Exchange (ETDEWEB)

Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

1976-01-01

About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with /sup 252/Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from /sup 252/Cf and 7000 rad from /sup 226/Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for /sup 252/Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from /sup 252/Cf and 5000 rad from /sup 226/Ra.

Radioactivity in wastes generated from shale gas exploration and production - North-Eastern Poland.

Science.gov (United States)

Jodłowski, Paweł; Macuda, Jan; Nowak, Jakub; Nguyen Dinh, Chau

2017-09-01

In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations were measured in 64 samples of wastes generated from shale gas exploration in North-Eastern Poland. The measured samples consist of drill cuttings, solid phase of waste drilling muds, fracking fluids, return fracking fluids and waste proppants. The measured activity concentrations in solid samples vary in a wide range from 116 to around 1100 Bq/kg for K-40, from 14 to 393 Bq/kg for U-238, from 15 to 415 Bq/kg for Ra-226, from 12 to 391 Bq/kg for Pb-210, from a few Bq/kg to 516 Bq/kg for Ra-228 and from a few Bq/kg to 515 Bq/kg for Th-228. Excluding the waste proppants, the measured activity concentrations in solid samples oscillate around their worldwide average values in soil. In the case of the waste proppants, the activity concentrations of radionuclides from uranium and thorium decay series are significantly elevated and equal to several hundreds of Bq/kg but it is connected with the mineralogical composition of proppants. The significant enhancement of Ra-226 and Ra-228 activity concentrations after fracking process was observed in the case of return fracking fluids, but the radium isotopes content in these fluids is comparable with that in waste waters from copper and coal mines in Poland. Copyright © 2017 Elsevier Ltd. All rights reserved.

Retention of aqueous {sup 226}Ra fluxes from a sub-aqueous mill tailings disposal at the Bois Noirs site (Loire, France)

Energy Technology Data Exchange (ETDEWEB)

Courbet, Christelle; Simonucci, Caroline; Dauzeres, Alexandre; Matray, Jean-Michel [French Institute for Radiation protection and Nuclear Safety - IRSN, Radiation Protection Division - PRP, Nuclear Waste and Geosphere Department - DGE, SRTG/LETIS, B.P. 17, 92262 Fontenay-Aux-Roses (France); Bassot, Sylvain [French Institute for Radiation protection and Nuclear Safety - IRSN, Radiation Protection Division - PRP, Nuclear Waste and Geosphere Department - DGE, SRTG/LAME, B.P. 17, 92262 Fontenay-Aux-Roses (France); Mangeret, Arnaud [French Institute for Radiation protection and Nuclear Safety - IRSN, Radiation Protection Division - PRP, Nuclear Waste and Geosphere Department - DGE, SEDRAN/BRN, B.P. 17, 92262 Fontenay-Aux-Roses (France)

2013-07-01

This study focuses on a sub-aqueous mill tailings disposal site located in France (Bois Noirs) where 1.3 million tons of uranium mill sludge (fine tailings fraction < 50 μm) have been disposed since the 60's in a man-made pond below 4 meters of water maintained artificially by a rock-fill dam. A significant attenuation of aqueous {sup 226}Ra activity is observed in ground waters. This paper presents the preliminary modeling work performed for evaluating the role of water-rock interactions on aqueous {sup 226}Ra attenuation through the dam. This modeling attempt, assuming thermodynamic equilibrium, aims at checking the hydrochemical conceptual model developed in a previous study, in which Ra retention through the dam was assumed to most likely result from sorption onto metallic oxide-hydroxides. A 2D coupled reactive transport model was conceived to test this hypothesis over time and identify the measurements required to verify its consistency over the long term. (authors)

The content of 226Ra, 210Pb, 210Po and 40K on tobacco of some cigarette brands were sold in Bandung, West Java

International Nuclear Information System (INIS)

Putu Sukmabuana

2016-01-01

This study on the measurements of 226 Ra, 210 Pb, 210 Po and 40 K natural radionuclides contained in tobacco smoke, in order to estimate the effective dose received by smoker has been carried out. The samples have been measured covering 14 brands of cigarettes are commonly sold and consumed in Indonesia. After the tobacco is dried and mashed, the concentration of 226 Ra, 210 Pb and 40 K counted using γ-ray spectrometry, for 80,000 seconds. It was obtained that the average concentration of 226 Ra was 4.18 ± 0.67 Bq/kg, for 210 Pb was 4.71 ± 0.82 Bq/kg, while the average concentration of 40 K was 26.50 ± 2.08 Bq/kg. 210 Po calculated based on radioactive equilibrium, the result was 4.09 ± 0.71 Bq/kg. By using a dose coefficients given by ICRP, the estimated annual effective dose received by the smoker was calculated. The average annual effective dose for 226 Ra was 80.46 ± 12.93 µSv/year, for 210 Pb was 28.47 ± 4.96 µSv/year, and 210 Po was 74.31 ± 12.96 µSv/year. Estimated effective dose for 40 K radionuclide can not be done because the dose coefficients for 40 K is not available in ICRP 71. By summing the average dose of 226 Ra, 210 Pb and 210 Po, obtained total effective dose estimated annual average was 183.24 µSv/year or around 14,5 % of the dose limit for radiation exposure by inhalation in the world (1260 µSv/year). In summary the effective dose above is still relatively small, but nevertheless when radioactive substances and chemicals in cigarette smoke enters the bloodstream it can affect the entire body. This is why smoking causes so many diseases, including cancer, heart disease and various lung diseases. (author)

Determination of Pb-210 and Ra-226 in sediments from Acude de Apipucos - Recife, Pernambuco, Brazil; Determinacao de chumbo-210 e radio-226 em sedimentos do Acude de Apipucos - Recife - Brasil

Energy Technology Data Exchange (ETDEWEB)

Souza, Vivianne Lucia Bormann de; Melo, Roberto Teodozio de; Figueiredo, Marcela Durao Cesar de; Rodrigues, Kelia Rejane Goncalves; Cunha, Manuela Silva da; Silva, Danubia B. da; Pedroza, Eryka de H., E-mail: vlsouza@cnen.gov.b, E-mail: rtmelo@cnen.gov.b [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Oliveira, Aristides [Hospital de Cancer de Pernambuco, Recife, PE (Brazil)

2011-07-01

This study aims to determine the age of sediment layers in Apipucos Reservoir, located in Recife, Brazil. Dating with {sup 210}Pb and {sup 226}Ra concentrations found in these sediments was used. A core with length of 70 cm and internal diameter of 5 cm was used for sediment sampling and each obtained profile was sectioned. Lead and radium were extracted from these samples by adding acids. {sup 210}Pb and {sup 226}Ra were determined in a gas flow proportional detector, based on the activities of their daughters. It was found that the CRS model (Constant Rate of Supply) to calculate the ages of sediment was more appropriate than CIC (Constant Initial Concentration). The chronology showed that the first sediment layers were 30 years old. (author)

Toxicity of injected radium-226 in immature dogs

Energy Technology Data Exchange (ETDEWEB)

Muggenburg, B.A.; Hahn, F.F.; Griffith, W.C. [and others

1995-12-01

This study was conducted to determine the toxicity of injected {sup 226}Ra in immature dogs and to compare the results with those from studies of injected {sup 226}Ra in young adult dogs. An historic objective of these studies, initiated at the University of Utah and continued at ITRI, was to compare the results in dogs to the population of dial painters who ingested {sup 226}Ra as young adults. Age at the time of exposure is considered to be an important factor in dosimetry and risk of developing radiation-induced disease, particularly bone cancer. In summary, dogs injected with {sup 226}Ra when immature had increased occurrences of bone tumors in a dose-related fashion.

Toxicity of injected radium-226 in immature dogs

International Nuclear Information System (INIS)

Muggenburg, B.A.; Hahn, F.F.; Griffith, W.C.

1995-01-01

This study was conducted to determine the toxicity of injected 226 Ra in immature dogs and to compare the results with those from studies of injected 226 Ra in young adult dogs. An historic objective of these studies, initiated at the University of Utah and continued at ITRI, was to compare the results in dogs to the population of dial painters who ingested 226 Ra as young adults. Age at the time of exposure is considered to be an important factor in dosimetry and risk of developing radiation-induced disease, particularly bone cancer. In summary, dogs injected with 226 Ra when immature had increased occurrences of bone tumors in a dose-related fashion

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

International Nuclear Information System (INIS)

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 226 Ra and 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

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

International Nuclear Information System (INIS)

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

1985-01-01

The Center for Human Radiobiology has identified 5784 persons by name and type of exposure to 226 Ra and 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. 27 references, 3 figures, 5 tables

STUDY OF NATURAL RADIOACTIVITY (226Ra, 232Th AND 40K) IN SOIL SAMPLES FOR THE ASSESSMENT OF AVERAGE EFFECTIVE DOSE AND RADIATION HAZARDS.

Science.gov (United States)

Bangotra, Pargin; Mehra, Rohit; Kaur, Kirandeep; Jakhu, Rajan

2016-10-01

The activity concentration of 226 Ra (radium), 232 Th (thorium) and 40 K (potassium) has been measured in the soil samples collected from Mansa and Muktsar districts of Punjab (India) using NaI (Tikl) gamma detector. The concentration of three radionuclides ( 226 Ra, 232 Th and 40 K) in the studied area has been varied from 18±4 to 46±5, 53±7 to 98±8 and 248±54 to 756±110 Bq kg -1 , respectively. Radium equivalent activities (Ra eq ) have been calculated in soil samples for the assessment of the radiation hazards arising due to the use of these soil samples. The absorbed dose rate of 226 Ra, 232 Th and 40 K in studied area has been varied from 8 to 21, 33 to 61 and 9 to 25 nGy h -1 , respectively. The corresponding indoor and outdoor annual effective dose in studied area was 0.38 and 0.09 mSv, respectively. The external and internal hazard has been also calculated for the assessment of radiation hazards in the studied area. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Determination of 226Ra and natural uranium concentration in Botafogo river

International Nuclear Information System (INIS)

Nascimento, M.B. do; Amaral, R.S.; Khoury, H.J.; Andrade Lima, R. de

1990-01-01

In the Brazilian Northeast region at the coastal area from Pernambuco to Paraiba there is a 4 km wide strip deposit of phosphate rock. This phosphate is used to produce fertilizes by a factory located at the border of the Botafogo river, which cross this area. The phosphate is associated with uranium and no research has been conducted on the river radioactive contamination due the natural processes and to the fertizer factory the present investigation was undertaken to determine 226 Ra and natural uranium concentration in the river water, near the factory. Results show that the radionuclide concentration increases sharply in front of the place of the factory discharge and then decreases rapidly to the same levels found before the factory, 0,01 Bq/1. (author) [pt

Characterisation of concrete containers for radioactive waste in the engineering tranches system at the Yugoslav R.A waste storing center

International Nuclear Information System (INIS)

Plecas, I.; Peric, A.; Drljaca, J.; Kostadinovic, A.

1987-10-01

Low and intermediate level radioactive waste represents 90% of total R.A. waste. It is conditioned into special concrete containers. Since these concrete containers are to protect safely the radioactive waste for 300 years, the selection of materials and precise control of their physical and mechanical properties is very important. In this paper results obtained with some concrete compositions are described. (author)

Radium-226 levels in Italian drinking waters and foods

International Nuclear Information System (INIS)

Mastinu, G.G.; Santaroni, G.P.

1980-01-01

Levels of 226 Ra in Italian waters and foods were measured. Results were similar to those found in other countries, except for some mineral waters with 226 Ra concentrations above 1 pCi/liter andup to 19 pCi/liter. No difinite correlation was found between the 226 Ra concentrations measured and the high natural background radiation levels determined in central Italy in previous work

Radium-226 on drinking water of Camaguey, Cuba

International Nuclear Information System (INIS)

Montalvan Estrada, Adelmo; Brigido Flores, Osvaldo; Barrera Caballero, Aldo; Escalante, Alexander

2001-01-01

The specific activity of Ra-226 in drinking water of Camaguey city, Cuba, was measured using the emanometric method. The specific activity of Ra-226 in drinking water ranged from 15 ± 5 mBq.l -1 to 39 ±12 mBq.l -1 . The mean specific activity of Ra-226 was found to be 27 ± 8 mBq.l -1 . No seasonal variation was found. Water samples were collected from the two main sources of drinking water: private wells and governmental water supply system, being the mean specific activities of Ra-226: 25 ± 7 mBq.l -1 and 31 ± 9 mBq.l -1 , respectively. Based upon measured concentrations the age-dependent associated effective doses due to the ingestion of Ra-226, as a consequence of direct consumption of drinking water, have been calculated. For the age interval 1 year to 5 years, the average effective dose was 6,2 μSv.y -1 , and for adults the average effective dose was 5,2 μSv.y -1 . (author)

Determination of Radium 226 in mexican phosphate fertilizers and gypsum by gamma spectrometry

International Nuclear Information System (INIS)

Godinez A, M.C.

1995-01-01

The 226 Ra isotope was determined in 17, 20 and 46% m/m phosphate fertilizers and gypsum. The samples of the fertilizers were dissolved in 10% v/v nitric acid solutions. The barium sulphate method was used for the precipitation of 226 Ra. On the other hand, alkaline fusion method was used to separate the 226 Ra from gypsum. The results indicated that 226 Ra was present in the phosphate fertilizers and gypsum. The 226 Ra concentrations present in these materials were between 10 -4 - 10 -5 μg g -1 . (Author)

Qualification of R.A. waste conditioning process and installations by ONDRAF/NIRAS

International Nuclear Information System (INIS)

Havard, P.; Faniel, L.; Voet, M.; Goeyse, A. de.

1993-01-01

ONDRAF/NIRAS in its role of national agency responsible for the management of radioactive waste in Belgium (including transport, intermediate storage and final disposal of the conditioned waste) has defined and enforces conditions for the acceptance (i.e. taking over) of conditioned waste packages. The waste acceptance conditions applicable at the present time are: 1. The conditioning process and installations are qualified by ONDRAF/NIRAS; 2. The waste packages are produced according to the qualified process and installations, and meet the technical specifications and acceptance criteria defined by ONDRAF/NIRAS; 3. The production of the waste packages is supervised by ONDRAF/NIRAS through an inspection and control programme specific to each conditioning process and associated installation, and has been found satisfactory. (author)

Adopted levels and derived limits for Ra-226 and the decision making processes concerning TENORM releases

International Nuclear Information System (INIS)

Paschoa, A.S.

2002-01-01

A fraction of a primary dose limit can be, in general, agreed upon as a dose related level to be adopted in decision-making processes. In the case of TENORM releases, fractions of primary dose levels for 226 Ra, 228 Ra, and 210 Po may be of particular importance to establish adopted levels for 226 Ra could be adopted at the highest portion of the natural background variation. Above such level, intervention and remedial action levels could also be adopted. All those levels would be fractions of the primary level, but translated in terms of derived limits expressed in practical units. Derived limits would then be calculated by using environmental models. In such approach 'critical groups' would have to be carefully defined and identified. In addition, the size of a critical group would be chosen to be used in environmental modeling. Site specific environmental models and parameters are desirable, though unavailable, or very difficult to obtain, in most cases. Thus, mathematical models and parameters of more generic nature are often used. A sensitive parametric analysis can make a ranking of the parameters used in a model, allowing one to choose how important each parameter will be for the model output. The paper will point out that when using the adopted levels and derived limits, as suggested above, the uncertainties and importance of the parameters entering an environmental model can make the difference for decision makers to take the right or wrong decision, as far as radiological protection is concerned. (author)

Norm waste in oil and gas industry: The Syrian experience

International Nuclear Information System (INIS)

Al-Masri, M.S.; Suman, H.

2001-01-01

This paper describes the Syrian experience in respect to Naturally Occurring Radioactive Materials (NORM) waste in Syrian oil and gas industry. NORM can be concentrated and accumulated in tubing and surface equipment of oil and gas production lines in the form of scale and sludge. NORM waste (scale, sludge, production water) is therefore generated during cleaning, physical or chemical treatment of streams. Uncontrolled disposal of this type of waste could lead to environmental pollution, and thus eventually to exposure of members of the public. The presence of NORM in Syrian oil fields has been recognized since 1987 and AECS has initiated several studies, in cooperation with oil companies, to manage such type of waste. Three categories of NORM waste in Syrian oil fields were identified. Firstly, hard scales from either decontamination of contaminated equipment and tubular using high-pressure water systems or mechanical cleaning at site are considered to contain the highest levels of radium isotopes ( 226 Ra, 228 Ra, 224 Ra). Secondly, sludge wastes are generated with large amount but low levels of radium isotopes were found. Thirdly, contaminated soil with 226 Ra as a result of uncontrolled disposal of production water was also considered as NORM waste. The first waste type (scale) is stored in Standard storage barrels in a controlled area; the number of barrels is increasing with time. High levels of radium isotopes were found in these scales. The options for disposal of these wastes are still under investigations; one of the most predominant thinking is the re-injection into abundant wells. For sludge waste, plastic lined disposal pits were constructed in each area for temporary storage. Moreover, big gas power stations have been built and operated since the last ten years. Maintenance operations for these stations produce tens of tones of scales containing radon daughters, 210 Pb and 210 Po with relatively high concentrations. The common practice used to dispose

Implementation of radon measurements to evaluate the suitability of using cement containers for storing radioactive waste containing Ra-226

International Nuclear Information System (INIS)

Shweikani, R.; Kheituo, M.; Hushari, M.; Ali, A. F.

2003-12-01

This work aimed at studying radon diffusion through walls of cubic cement containers containing inside radioactive waste rich in Radium-226. In addition, the effect of the wall thickness on radon exhalation and external gamma exposure were also studded. Cubic cement molds were prepared with different dimensions ranged from 5 to 11 cm containing central cubic holes to contain the radioactive materials with dimensions ranged from 2 to 7 cm. The thicknesses of the walls were varied from 1 to 4 cm. Radon exhalation was studied by placing each pre-prepared cement specimen in a tightly closed glass container (desiccators, volume 7 liters) provided with input and output gas system circulation for one week. Active method (Lucas cell) was used to measure the concentration of radon in the container. It was noticed that radon concentration increased with the increase of the radioactive materials inside the specimens. This was simply explained as it is due to the increase of the amount of radium-226 in the specimen with will definitely lead to the increase of radon production. In addition, it was noticed that radon concentration were increased by increasing the thickness of the specimen wall for fixed amount of the radioactive materials inside. This result was unexpected. Therefore, many attempts were performed to explain it. For that, the mechanism of cement solidifications and structure of cement after solidification were studied. The conditions which affect the size and number of the formed pores in the specimens were also studied assuming that increasing the wall thickness will increase porosity and lead to the increase diffusion paths. It was concluded that it is possible to use the cubic cement containers to stop gamma radiation from the radioactive materials, but it is not possible to use them to stop radon unless special arrangements are performed. (author)

The influence of age at time of exposure to 239Pu or 226Ra on retention, distribution, survival and tumor induction in Beagles

International Nuclear Information System (INIS)

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

1991-01-01

The influence of age at injection of 226 Ra or 239 Pu on skeletal deposition and local distribution, the pattern of bone tumor formation and post-injection survival were studied in parallel short-term mechanistic and lifetime toxicity experiments. Beagles received a single intravenous injection of 226 Ra or 239 Pu at age 3 months (juveniles), 17-19 months (young adults) or 60 months (mature). Data from short-term mechanistic-dosimetric studies and from one dosage level (41 kBq 226 Ra/kg or 11 kBq 239 Pu/kg body mass) of each of the toxicity experiments were compared. Skeletal growth and turnover produced differential initial deposition and distribution patterns typical for each age group. The highest bone tumor incidence was seen in the young adult groups. Differences were observed in bone tumor location between dogs in the same age group given radium or plutonium and among age groups injected with either radionuclide, and some of these could be explained by differences in local dose distributions (e.g., trabecular vs. cortical bone). Cox regression indicated no significant differences in post-injection survivals (uncorrected for the different pre-injection periods) of Ra-injected groups, but there was a statistically significant difference among the Pu-injected groups. Neutron-induced autoradiography showed that differences in the effects of Pu in the three age groups were due primarily to the age- and time-dependent local distribution of the nuclide

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

International Nuclear Information System (INIS)

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

2016-01-01

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. - Highlights: • Ra and U isotopes were measured in soils and plant crops in farms in Saudi Arabia. • Ra and U activities in plant roots (R) slightly exceeded that in their fruits (F). • Ra/U activity ratios showed preferential translocation of U

226Ra and other radionuclides in water, vegetation, and tissues of beavers (Castor canadensis) from a watershed containing U tailings neat Elliot Lake, Canada

International Nuclear Information System (INIS)

Clulow, F.V.; Mirka, M.A.; Dave, N.K.; Lim, T.P.

1991-01-01

Radionuclide levels were measured in tissues, gut contents, diet items, and water at site of capture, of adult beavers from the Serpent River drainage basin which contains U tailings at Elliot Lake, Ontario, and from nearby control sites. Levels of 226 Ra in beaver bone, muscle and kidney were highest in animals from locations close to U tailing; liver levels did not vary by site. Environmental 226 Ra levels were within ranges previously reported at these or similar locations elsewhere; levels in beaver gut contents reflected levels in diet items. Concentration ratios exceeded unity only between some vegetation items and beaver bone at the Elliot Lake site and were less than 0.19 between vegetation and other tissues. In two beavers with tissue levels of 226 Ra higher than others sampled, neither 232 Th nor 230 Th were detected in bone, muscle or liver tissues. U-238 was measurable in bone, muscle and liver; 228 Th in bone, 210 Po bone, muscle and liver; and 210 Pb was measurable only in bone. Estimated yearly intakes of radionuclides by people eating beavers were calculated to be below current allowable levels set by the Canadian regulatory authorities. (author)

Natural radionuclides, 226Ra, 228Ra and 210Pb, determined in mineral water springs from Parque das Águas de Caxambu, and assessment of the committed effective doses

International Nuclear Information System (INIS)

Meneghini, Arthur A.; Damatto, Sandra R.; Oliveira, Joselene; Prilip, Amanda

2017-01-01

The increase of mineral water consumption and its medicinal use results in the necessity of characterization of these waters sources, once that water is a vital part of human diet. In the mineral waters, besides stable elements, responsible of the chemical composition, the presence of natural radionuclides from the 238 U, 232 Th, 235 U series and 40 K gives the radiation property. The incorporation of these radionuclides through the ingestion and external treatment of mineral waters are a very important point, due the ionizing radiation of these radionuclides are harmful to the organism. The largest mineral water park of the world is situated in Brazil, in the city of Caxambu, called Parque das Águas de Caxambu. In this park are 12 fountains distributed in the park, also a tubular well of 60 meters of depth which regularly provide water spouts, geyser, and another spring located inside the Gloria Hotel. Therefore, the aim of this work was to evaluate the activity concentrations of the radionuclides 226 Ra, 228 Ra and 210 Pb in the mineral waters springs collected at the 'Parque das Águas de Caxambu' and in the Gloria Hotel, as well as to estimate the committed effective doses due to the consumption of these waters. In six campaigns, the radionuclides with the highest concentrations were 226 Ra and 228 Ra in the springs D. Ernestina, Beleza and Venâncio. These springs also presented the highest values of the committed effective dose. (author)

{sup 226}Ra, {sup 228}Ra and {sup 210}Pb determination in surface water and groundwater by liquid scintillation counting

Energy Technology Data Exchange (ETDEWEB)

Faria, Ligia S.; Moreira, Rubens M., E-mail: ligsfaria@gmail.com, E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2015-07-01

The municipalities of Brumadinho and Nova Lima are located in the metropolitan region of Belo Horizonte city, in the State of Minas Gerais. These two sites are important due to being located inside an Environmental Protection Area inserted in the Iron Quadrangle. In addition to the mineral wealth, the region has geological features that include quartz conglomerates associated with uranium and a significant groundwater potential exhibiting quite peculiar and complex hydrogeological features, such as the quartzite aquifer itself. Nuclear techniques applied to hydrology, such as Liquid Scintillation Counting technique (LSC), make possible the evaluation of natural radioactivity in surface water and groundwater. The objectives of this study were the determination of the activities of the long half-life radionuclides of the uranium and thorium series, such as {sup 226}Ra, {sup 228}Ra and {sup 210}Pb, and provide an effective methodology to define if the direct consumption of these waters can cause risk to health due to its radioactivity. The results were compared with the recommendations of the Ministry of Health. (author)

Micro-extraction procedures for the determination of Ra-226 in well waters by SF-ICP-MS

International Nuclear Information System (INIS)

Lariviere, D.; Epov, V.N.; Reiber, K.M.; Cornett, R.J.; Evans, R.D.

2005-01-01

The radium-226 (t 1/2 = 1622 years) content of highly alkaline well water collected from the United Arab Emirates (UAE) was measured by double focusing sector-field inductively coupled plasma-mass spectrometry (SF-ICP-MS) after separation of the radium from other alkaline earth elements using a newly developed procedure. The results were comparable with those obtained by α-spectrometry for samples with concentrations ranging from 6.75 to 459 pg/L (0.25 to 17 Bq/L). Instrumental sensitivity on matrix-free samples was compared for two sample introduction systems, i.e. an Apex-Q high sensitivity system and a concentric nebulizer. A 12-fold improvement in sensitivity (instrumental detection limit = 1.5 pg/L or 55 mBq/L) was found when the Apex-Q system was used. Two chromatographic methods were tested for the sequential separation of the alkaline earth elements contained in the well water samples in order to reduce matrix and polyatomic interference effects. Optimal elution parameters were determined and used for the separation and pre-concentration of Ra-226 in those samples. A method detection limit of 0.189 pg/L (7 mBq/L), which corresponds to a mass of 0.38 fg of Ra-226 in the sample, was achieved. Only 2 mL of sample is necessary when a combination of 50 W-X8 and Sr*Spec resin, which are reusable, are utilized for the separation. This new analytical protocol significantly reduces sample preparation time resulting in a throughput rate of approximately 20 samples in only 8 h; faster than the other published extraction procedures

Natural Radium-226 accumulation in the human thyroid gland

International Nuclear Information System (INIS)

Simon, Steven L.; Ibrahim, Shawki A.; Barden, Adam O.; VanMiddlesworth, Lester

2008-01-01

Full text: Small amounts of Ra-226 and other radium isotopes routinely enter the human body through normal dietary intake and, in some cases, through occupational exposure. Currently accepted biokinetic models for radium in the human body assume a uniform distribution among all soft tissues and a short retention time in those tissues. These assumptions persist despite publications in the mid-1980s indicating that radium concentrations in tissue are related to calcium levels in each organ, implying that the thyroid gland could accumulate greater concentrations of radium isotopes than any other tissue. Moreover, the natural intake or production of sulfate or barium compounds in the body could serve to precipitate radium in the thyroid gland, thereby immobilizing it, with the result that the radionuclide stays resident for many years. Evidence of both accumulation and immobilization of Ra-226 in thyroids of grazing animals has been documented since the 1960s by one of us (LVM). Little is known, however, about the concentration and retention of radium in the human thyroid. Reported here, for the first time, are Ra-226 measurement data from about 100 human thyroids collected from over 95 persons with no known occupational exposure to radium with lifetime residences in the US and other countries, one person who routinely ingested a homeopathic preparation containing Ra-226, and three uranium miners. Sensitive measurements were made using the radon emanation technique. Regardless of the origin of the thyroid sample, Ra-226 activity was almost always detected above the detection limit of 0.65 mBq when at least 10 g of thyroid tissue were available. Our analyses to-date suggests a background concentration in human thyroids of about 0.1 ±0.01 Bq/kg, considerably greater than the commonly reported literature value of 0.003 Bq/kg in soft tissues. In addition, our measurements indicate concentrations of Ra-226 in the three uranium miners (whose exact job description was

Determination of the concentration of 238U, 234U, 232Th, 228Th, 228Ra, 226Ra and 210Pb in the feces of workers from a mining company of niobium and their families

International Nuclear Information System (INIS)

Oliveira, Roges de; Lopes, Ricardo T.; Melo, Dunstana R.; Juliao, Ligia M.Q.C.

2005-01-01

The object of this study consists of an open mine from which Niobium ore (pyrochlore) is extracted and a metallurgy company, where Fe-Nb alloys are produced for export. For geological reasons, the main ore is associated to natural radionuclides U and Th, and its decay products. The concentration of 234 U, 238 U, 232 Th, 226 Ra and 228 Ra, 228 Th, including 210 Pb in fecal excretion of 12:0 am, 29 workers and 13 family members were determined. The technique employed for the determination of the elements was the sequential method of radiochemical separation, followed by alpha spectrometry and counting α and β in proportional detector. Statistically significant difference was observed in the concentration of 234 U and 238 U, in feces samples, among the group of mining workers and family members; as well as for 232 Th in the feces of workers of crushing and metallurgy groups when compared with the Family Group. No statistically significant difference was detected at a concentration of 226 Ra, 228 Ra and 210 Pb, in feces of any group of workers of the installation in relation to the family group

Assessment of "2"2"6Ra, "2"2"8Ra and "2"1"0Pb concentration in mineral waters from Parque das Águas de Lambari and Contendas, MG and evaluation of the committed effective doses

International Nuclear Information System (INIS)

Wakasugi, Denise S.M.; Damatto, Sandra R.

2017-01-01

The exploration of several Brazilian hydromineral resorts, that have springs of radioactive mineral water consumed by the population support the relevance of the present work. This study is being developed in the IPEN with the aid of the responsible for Parque das Águas de Lambari and Contendas. Thereby, this work aims to determine the activity concentrations of "2"2"6Ra, "2"2"8Ra and "2"1"0Pb to verify the influence of seasonality in these water parks springs. Thereunto, gross alpha and beta measurements were used after radiochemical separation for these radionuclides determination and measurement in a low background proportional detector. The results showed that Parque das Águas de Lambari presented highest concentration values when compared with Contendas. In Parque das Águas de Contendas , the highest concentration values were 77 ± 5 mBq/L and 129 ± 5 mBq/L for "2"2"6Ra for Gasosa II springs and "2"2"8Ra for Gasosa I spring, respectively, which correspond to the spring season; for "2"1"0Pb, 27 ± 2 mBq/L for Magnesiana spring in the same season. In Parque das Águas de Lambari, the highest concentration values for "2"2"6Ra was 177 ± 2 mBq/L and for "2"1"0Pb, 36 ± 2 mBq/L, both in the Magnesiana spring, for the summer season and 135 ± 5 mBq/L for "2"2"8Ra, in Magnesiana spring, for the spring season. The data were analyzed through descriptive and correlational statistical techniques. Therefore, it was possible to evaluate the committed effective doses due to the consumption of these waters and to assess the radiological risk for the radionuclides studied. (author)

Radionuclide release from simulated waste material after biogeochemical leaching of uraniferous mineral samples

International Nuclear Information System (INIS)

Williamson, Aimee Lynn; Caron, François; Spiers, Graeme

2014-01-01

Biogeochemical mineral dissolution is a promising method for the released of metals in low-grade host mineralization that contain sulphidic minerals. The application of biogeochemical mineral dissolution to engineered leach heap piles in the Elliot Lake region may be considered as a promising passive technology for the economic recovery of low grade Uranium-bearing ores. In the current investigation, the decrease of radiological activity of uraniferous mineral material after biogeochemical mineral dissolution is quantified by gamma spectroscopy and compared to the results from digestion/ICP-MS analysis of the ore materials to determine if gamma spectroscopy is a simple, viable alternative quantification method for heavy nuclides. The potential release of Uranium (U) and Radium-226 ( 226 Ra) to the aqueous environment from samples that have been treated to represent various stages of leaching and passive closure processes are assessed. Dissolution of U from the solid phase has occurred during biogeochemical mineral dissolution in the presence of Acidithiobacillus ferrooxidans, with gamma spectroscopy indicating an 84% decrease in Uranium-235 ( 235 U) content, a value in accordance with the data obtained by dissolution chemistry. Gamma spectroscopy data indicate that only 30% of the 226 Ra was removed during the biogeochemical mineral dissolution. Chemical inhibition and passivation treatments of waste materials following the biogeochemical mineral dissolution offer greater protection against residual U and 226 Ra leaching. Pacified samples resist the release of 226 Ra contained in the mineral phase and may offer more protection to the aqueous environment for the long term, compared to untreated or inhibited residues, and should be taken into account for future decommissioning. - Highlights: • Gamma counting showed an 84% decrease in 235 U after biogeochemical mineral leaching. • Chemical digestion/ICP-MS analysis also showed an 84% decrease in total U. • Over

Fractionation of chemical elements including the REEs and 226Ra in stream contaminated with coal-mine effluent

International Nuclear Information System (INIS)

Centeno, L.M.; Faure, G.; Lee, G.; Talnagi, J.

2004-01-01

Water draining from abandoned open-pit coal mines in southeastern Ohio typically has a low pH and high concentrations of Fe, Al and Mn, as well as of trace metals (Pb, Cu, Zn, Ni, Co, etc.) and of the rare earth elements (REEs). The cations of different elements are sorbed selectively by Fe and Al hydroxide precipitates which form with increasing pH. As a result, the trace elements are separated from each other when the hydroxide precipitates are deposited in the channel of a flowing stream. Therefore, the low-energy environment of a stream contaminated by mine effluent is a favorable site for the chemical fractionation of the REEs and of other groups of elements with similar chemical properties. The interpretation of chemical analyses of water collected along a 30-km-stretch of Rush Creek near the town of New Lexington, Perry County, Ohio, indicates that the abundances of the REEs in the water appear to change downstream when they are normalized to the REE concentrations of the mine effluent. In addition, the Ce/La ratios (and those of all REEs) in the water decrease consistently downstream. The evidence indicates that the REEs which remain in solution are enriched La and Ce because the other REEs are sorbed more efficiently. The solid Fe(OH) 3 precipitates in the channel of Rush Creek upstream of New Lexington also contain radioactive 226 Ra that was sorbed from the water. This isotope of Ra is a decay product of 238 U which occurs in the Middle Pennsylvanian (Upper Carboniferous) coal and in the associated shale of southeastern Ohio. The activity of 226 Ra of the Fe(OH) 3 precipitates increases with rising pH, but then declines farther downstream as the concentration of Ra remaining in the water decreases

Study of the specific activity concentrations of 40K, {sup 226}Ra, {sup 228}Ra and {sup 232}Th in vegetables and their respective covering tissues (peels)

Energy Technology Data Exchange (ETDEWEB)

Lopes, J.M.; Garcêz, R.W.D., E-mail: marqueslopez@yahoo.com.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Silva, A.X. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Escola Politécnica

2017-07-01

This work presents an analysis of specific concentrations of {sup 40}K, {sup 226}Ra, {sup 228}Ra and {sup 232}Th in some vegetables that are part of the diet of the population of the state of Rio de Janeiro. Furthermore, was analyzed the concentrations of radionuclides in the same coating tissue that compose the vegetables. It can notice an increase of the specific concentration of {sup 40}K in the peels of vegetables that have little or no contact with the ground. Among the samples examined, only the pumpkin showed measurable amount of {sup 137}Cs both saves and in the skin. (author)

Bioavailability pf radionuclides 226Ra, 228Ra and 210Pb present in Brazilian phosphogypsum and phosphate fertilizers

International Nuclear Information System (INIS)

Russo, Ana Carolina; Saueia, Catia H.R.; Mazzilli, Barbara P.

2011-01-01

Phosphogypsum (PG) is a by-product of phosphate fertilizers industries. The USEPA classified PG as a - Technologically Enhanced Naturally Occurring Radioactive Material (TENORM). Its worldwide production on 2006 was estimated in 150 million tons. Annually the three main phosphate industries in Brazil are responsible for 5.5x106 tons of phosphogypsum, which is stored in stacks. The level of radionuclides present in phosphogypsum is well-known and makes its disposal or reutilization an environmental concern. Part of this byproduct can be reused, for example, to improve fertility of agricultural soils. To assess the long term environmental impact of radioactive contamination of ecosystems, information on source term including radionuclide speciation, mobility and biological uptakes have high importance. This paper intends to evaluate the bioavailability of the radionuclides 226 Ra, 228 Ra and 210 Pb to the environment by following a procedure established by the EC (European Community), which includes a single EDTA-NH 4 0.05M extraction at pH 7.0 prior to the analyses. These results is compared with the total activity concentration of these radionuclides in Brazilian PG and the most used phosphate fertilizers (SSP, TSP, MAP and DAP). This procedure intends to represent on a more realistic way the leaching of radionuclides from PG and fertilizers to soil and agricultural products. (author)

Activity concentration and radiological impact assessment of 226Ra, 228Ra and 40K in drinking waters from (OML) 30, 58 and 61 oil fields and host communities in Niger Delta region of Nigeria

International Nuclear Information System (INIS)

Agbalagba, E.O.; Avwiri, G.O.; Ononugbo, C.P.

2013-01-01

This paper presents the concentrations of naturally occurring radionuclides ( 226 Ra, 228 Ra and 40 K) measured in hand dug wells, boreholes and river waters collected from three oil mineral leases (OML) 30, 58 and 61 oil and gas fields onshore of the Niger delta, using gamma spectroscopy. Fifty-four water samples from the three sources of drinking water supply were collected within the oil fields and host communities and three water samples from a control site. The results showed average activity concentrations of 226 Ra, 228 Ra and 40 K as 8.9 ± 1.0, 8.1 ± 0.9 and 39.8 ± 3.3 respectively for hand dug wells, 4.4 ± 0.8, 4.6 ± 0.5 and 28.5 ± 3.0 for borehole water and 8.2 ± 1.0, 6.7 ± 0.7 and 32.1 ± 3.5 for river water respectively. These 226 Ra, 228 Ra and 40 K average are well above the WHO permissible levels of 1.0, 0.1 and 10 BqL −1 respectively and also above the control values. Although the hazard indices calculated are still within their tolerable levels, the estimated committed effective dose due to intake of the sampled water for all the four age groups considered are far above the ICPR 0.1 mSvyr −1 maximum permissible limit. The result indicates some level of water pollution in the studied area. - Highlights: ► The concentration of natural radioactive series nuclides varies widely within oil fields and from one oil field to another in the OML30. ► The radionuclide activity concentrations in most water samples are higher than world average values. ► Calculated hazard indices and committed effective dose to assess the potential radiological health risk in samples are well above their permissible limit. ► The sources of water in these oil fields have been polluted and may cause some health hazard to the public users.

Adopted levels and derived limits for Ra-226 and the decision making processes concerning TENORM releases

International Nuclear Information System (INIS)

Paschoa, A.S.

2002-01-01

A fraction of a primary dose limit can be, in general, agreed upon as a dose related level to be adopted in decision-making processes. In the case of TENORM releases, fractions of primary dose levels for 226 Ra, 228 Ra, and 210 Po may be of particular importance to establish adopted levels and derived limits to guide decision making processes. Thus, for example, a registration level for 226 Ra could be adopted at the highest portion of the natural background variation. Above such level, intervention and remedial action levels could also be adopted. All those levels would be fractions of the primary level, but translated in terms of derived limits expressed in practical units. Derived limits would then be calculated by using environmental models. In such approach 'critical groups' would have to be carefully defined and identified. In addition, the size of a critical group would be chosen to be used in environmental modeling. Site specific environmental models and parameters are desirable, though unavailable, or very difficult to obtain, in most cases. Thus, mathematical models and parameters of more generic nature are often used. A sensitive parametric analysis can make a ranking of the parameters used in a model, allowing one to choose how important each parameter will be for the model output. The paper will point out that when using the adopted levels and derived limits, as suggested above, the uncertainties and importance of the parameters entering an environmental model can make the difference for decision makers to take the right or wrong decision, as far as radiological protection is concerned. (author)

Determinations of 90Sr, 137Cs, 226Ra, 228Ra, 210Pb, 210Po contents in chinese diet and estimations of internal doses due to these radionuclides

International Nuclear Information System (INIS)

Zhu Hongda; Wang Shouliang; Meng Wei; Wang Daoping; Zheng Xiujun; Liu Qingfen; Liu Peng

1993-01-01

As a part of Chinese Total Diet Survey taken place in 1990, the authors report the determined results on 90 Sr, 137 Cs, 226 Ra, 228 Ra, 210 Pb and 210 Pb and 210 Po contents in various foods of Chinese total diet. Based on obtained dietary composition and the determined contents, the Annual Intakes (AI) and Committed Dose Equivalents (CDE) for the public by ingestion were estimated. It is shown that the total CDE for 6 radionuclides is about 0.24 mSv/a. The food categories and nuclides whose relative contributions to the total are dominant were vegetables, aquatic products and cereal, and 210 Pb, 210 Po, 228 Ra, respectively. The results have updated the data from 1982 survey and have complemented important information for water consumption. The regional difference of dietary compositions and resultant internal doses are discussed as well

Activity concentrations and population dose from radium-226 in food and drinking water in Taiwan

International Nuclear Information System (INIS)

Yenchuan Kuo; Shuying Lai; Chingchung Huang; Yuming Lin

1997-01-01

The purpose of this study was to determine the radioactivity of 226 Ra in environmental samples in Taiwan. Fish, pork, rice, flour, chicken, vegetable, milk, fruit, egg and water samples were collected and pretreated by radiochemical procedure to extract the 226 Ra, and the activity concentrations of 226 Ra were determined using a liquid scintillation counter. The 226 Ra content of groundwater was 12.0 mBq 1 -1 . The 226 Ra contents of the food ranged from 0.02 Bq kg -1 fresh to 0.17 Bq kg -1 fresh. The annual internal dose from ingestion of 226 Ra from food and drinking water per caput was evaluated to be 7.5 μSv. (author)

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Naturally occurring radioactive materials (NORM) wastes in oil fields are a radiological problem, but they are useful tools

International Nuclear Information System (INIS)

Othman, Ibrahim; Al-Masri, Mohammad Said

2008-01-01

Produced water, scales and sludges associated with the production of oil and gas contains enhanced concentrations of radium isotopes. Uncontrolled disposal of these wastes could lead to environmental pollution and thus to radiation exposure of members of the public. In the present work, radium isotopes in scales accumulated in oil field equipment, and produced water have been used for dating the deposited scales, studying between wells interactions and water flooding processes in addition to dating contaminated soils in the Syrian oil fields. The 228 Ra/ 226 Ra activity ratio in scales can be considered a fingerprint of the Th/U mass ratio in the geological formation of the reservoir. The 228 Ra/ 226 Ra activity ratio variations were found to reflect the variability of the Th/U mass ratio of the geological formation, suggesting two different source rock types found in the Syrian oil fields. The calculated mean Th/U mass ratio for these two possible types of source rock were 2.4 and 5.78. In addition, the 228 Ra/ 226 Ra mean activity ratio was also used to estimate the age of some deposited scales in tubulars; the results were compared with the 224 Ra/ 228 Ra activity ratio dating method. Moreover, 228 Ra/ 226 Ra, 224 Ra/ 228 Ra and 210 Pb/ 226 Ra activities ratios in contaminated soils due to disposal of production water were used to date contaminated sites at the oil fields; the results have been found to be in agreement with the actual disposal date. The methods can be used by the regulatory body to assess any uncontrolled disposal of such waste. (author)

The use of Pb-210/Ra-226 and Th-228/Ra-228 dis-equilibria in the ageing of otoliths of marine fish

International Nuclear Information System (INIS)

Smith, J.N.; Nelson, R.; Campana, S.E.

1991-01-01

Naturally-occurring isotopes of radium are ideally suited as tracers for chemical uptake in the calcified tissues of marine organisms since radium is a water soluble, bio-geochemical analogue for calcium. Assays designed to exploit this uptake mechanism can be used to determine the longevity of certain species of fish. Measurements of Pb-210/Ra-226 disequilibria in the otoliths of redfish have revealed that this species of fish can live to ages in excess of 75 years in coastal waters off Nova Scotia, Canada. Measurements of the Th-228/Ra-228 disequilibria in the otoliths of the much shorter-lived silver hake and flying fish may provide estimates of longevity on time scales of 0-10 years, which could then be used to evaluate the accuracy of currently-used ageing models based on otolith annulus counts. Age determinations of fish based on natural radioisotopes can result in significant improvements in the assessment and management of certain fisheries resources. (author)

Ingestion of radium 226 and its evaluation in a selected population group

International Nuclear Information System (INIS)

Ivan, J.; Slovak, M.; Abel, E.; Patzeltova, N.

1976-01-01

The activity of 226 Ra was followed in the drinking water of the West Slovakia region and in the all-day food intake. The volume activities of 226 Ra in drinking water were in the range 0 to 63 mBq.l -1 (0.0 to 1.7 pCi.l -1 ) with the mean value 9.3 mBq.l -1 (0.25 pCi.l -1 ). The average activity of 226 Ra in the food, as expressed per person and day, was 47.7 mBq (1.29 pCi). A general intake of 226 Ra by ingestion in the observed group, also calculated per person and day, was 57 mBq (1.54 pCi) on the average. The value found was used for the evaluation of the group exposure of a homogeneous group of boarders of a university canteen. The values obtained indicate an average exposure to 226 Ra. The calculated value of the annual dose equivalent of 226 Ra to the skeleton in adults was 2.48 mrem, with the corresponding dose equivalent being 0.119 rem; these values are small in view of the above mentioned annual 226 Ra intake, but are not negligible with regard to the ICRP recommendations. (author)

Study of the specific concentrations of 40K, 224Ra, 226Ra and 228Ra in some seasonings marketed in Rio de Janeiro City

International Nuclear Information System (INIS)

Garcêz, Ricardo W.D.; Lopes, José M.; Silva, Leandro B.; Silva, Ademir X. da; Lima, Marco A.F.

2017-01-01

The seasoning are vegetables substances used in foods to enhance their flavor, aroma and color. This work presents an investigation of the activity concentration of Naturally Occurring Radioactive Materials (NORMs) in 28 samples of seasoning utilized by brazilian population. The seasoning samples were measured using gamma spectroscopy technique with a high-purity germanium (HPGe) detector, a non-destructive nuclear method and with the LabSOCS software for the calculation of the efficiency curve. The analysis shows that the activity concentration of 40 K was measured in all samples and ranges from 21.0 Bq/kg to 1288 Bq/kg. The highest concentration activity of 40 K was measured to 'cheiro verde', a local seasoning made of chives (Allium Schoenoprasum) and parsley (Petroselinum Crispum), while annatto, made with the fruit of Bixa Orelhana, had the lowest activity concentration. Brazil nut (Bertholletia Excelsa) presented the highest concentrations for 226 Ra and 228 Ra with 24 Bq/kg and 25.7 Bq/kg, respectively and black pepper (Piper Nigrum) presented the highest concentration for 224 Ra with 33.9 Bq/kg. The highest effective dose for members of the public due to ingestion was 23.5 μSv/y due to Brazil nut and the lowest effective dose was found for annatto: 0.13 μSv/y. The syrian seasoning sample present specific concentration of 6.1±1.1 Bq/kg for 137 Cs and 0.08 μSv/y of effective dose. The values found in this work do not represent a risk to human health. (author)

Measurement of 226Ra, 232Th and 40K radioactivity contents in by-product phosphogypsum from phosphate fertilizer industry using gamma ray spectrometric method

International Nuclear Information System (INIS)

Demirel, H.; Parmaksiz, A.; Vural, M.; Cakir, I.T.; Demircioglu, B.; Yucel, H.

2004-01-01

Full text: Phosphatic fertilizers are produced from the industrial processing of rock phosphate ores which are known to contain naturally occurring radionuclides such as 238 U and its daughter products. A high volume by-product known as phosphogypsum (PG) from the production of phosphoric acid and phosphate fertilizer causes serious storage and environmental problems in phosphoric acid industries. During the phosphoric acid production process, 226 Ra (t 1/2 =1600 y) ends up in PG which has chemical analogous to calcium element. Since the stockpiles of PG near the phosphatic fertilizer plants are huge amounts, the radioactivity contained in PG has measured in view of environmental radioactivity problem. In this work, the natural radioactivity in eighty PG samples taken from a stock near Samsun phosphoric fertilizer plant was measured by a high resolution gamma ray spectrometer. The mean activity of 226 Ra in PG samples has been found to be 546 Bq.kg -1 . However, the activities of 232 Th and 40 K measured in PG samples are negligibly small. In the presented paper, the gamma spectrometric method employed for this work is discussed and the radiological risk impact of radon gas emanation from 226 Ra mainly contained in PG, has been assessed

226Ra and 210Pb lixiviation sediments from the region of uranium mine and mill in Pocos de Caldas, contaminated in laboratory by river water and chemical agents, mobility and availability in soils

International Nuclear Information System (INIS)

Oliveira, A.E. de.

1982-01-01

Leaching experiments of river bottom sediments, contaminated in the laboratory with 226 Ra or 210 Pb, by river waters or solutions of inorganic salts and mobility experiments of these radionuclides added to soil columns and leached by a volume of distilled or river water, equivalent to the average annual rain precipitation in the region, are performed. The determination of 226 Ra and 210 Pb exchangeable fractions in soils contaminated in the laboratory are studied too. The results, as a whole, lead to the conclusion that 226 Ra should be considered, potentially, the radionuclide most able to increase the population radiation dose, through the ingestion of contaminated water and foodstuff. (M.A.C.) [pt

Distribution of 226Ra, 232Th, and 40K in soils of Rio Grande do Norte (Brazil)

International Nuclear Information System (INIS)

Malanca, A.; Pessina, V.; Dallara, G.

1996-01-01

A survey programme aimed at studying the environmental radioactivity in the Brazilian state of Rio Grande do Norte was undertaken. Fifty-two soil samples, together with two rock and two uraniferrous ore samples were collected from the eastern and central regions of this state. Concentrations of radioelements in samples were determined by γ-ray spectrometry. The average concentrations of 226 Ra, 232 Th, and 40 K in the surveyed soils were 29.2 ± 19.5 (SD), 47.8 ± 37.3, and 704 ± 437 Bq kg -1 , respectively. Higher values were found in the rock samples. The distributions of 226 Ra and 232 Th were fitted by log-normal curves. Radiological measurements carried out with a portable scintillometer at the sampled sites revealed an average absorbed dose rate of 55 ± 27 (SD) nGy h -1 . Computed dose rates obtained through the Beck formula ranged from 15-179 nGy h -1 , with a mean value of 72.6 ± 38.7 (SD) nGy h -1 , and their distribution fitted a log-normal curve. An annual average effective dose equivalent of 552 μSν (range: 117-1361 μSν) was estimated for 51 sites in Rio Grande do Norte. (author)

The measurement of activities of 226Ra, 232Th, 40K in phosphogypsum by gamma ray spectrometry

International Nuclear Information System (INIS)

Parmaksiz, A.

2004-06-01

Phosphatic fertilizers are produced from the industrial processing of rock phosphate ores which are known to contain naturally occuring radionuclides such as 238 U and its daughter products. A high volume by-product known as phosphogypsum (PG) from the production of phosphoric acid and phosphate fertilizer causes serious storage and environmental problems in phosphoric acid industries. During the phosphoric acid production process, 226 Ra (t 1/2 =1600 y) ends up in PG which has chemical analogous to calcium periodical table. Since the stockpiles of PG near the phosphatic fertilizer plants are huge amounts, the radioactivity contained in PG has to measured in view of environmental radioactivity problem. In this work, the natural radioactivity in eighty PG samples, issued from a stock of about 60.000 tones was measured by a high resolution gamma ray spectrometer with a HPGe detector. The averaged activity of 226 Ra in PG has been found to be 546 Bq.kg -1 . However, the activities of 232 Th and 40 K measured in PG samples are negligibly small. The extra gamma radiation dose rate arising from 1 - 1.5 kg of PG is estimated to be about 241 nGy/h from 1 m ground level applied in 1 m 2 surface area of field

Treatment methods and comparative risks of thorium removal from waste residues

International Nuclear Information System (INIS)

Porter, R.D.; Hamby, D.M.; Martin, J.E.

1997-07-01

This study was done to examine the risks of remediation and the effectiveness of removal methods for thorium and its associated radioactive decay products from various soils and wastes associated with DOE's Formerly Utilized Sites Remedial Action Program (FUSRAP). Removal of 230 Th from uranium process residues would significantly reduce the buildup of 226 Ra (half-life of 1600 years), and since 230 Th concentrations at most of the important sites greatly exceed the 226 Ra concentrations, such removal would reduce the accumulation of additional radiation risks associated with 226 Ra and its products; and, if treatment also removed 226 Ra, these risks could be mitigated even further. Removal of 232 Th from thorium process residues would remove the source material for 228 Ra, and since 228 Ra has a half-life of 5.76 years, its control at FUSRAP sites could be done with land use controls for the 30--50 years required for 228 Ra and the risks associated with its decay products to decay away. It must be recognized, however, that treatment methods invariably require workers to process residues and waste materials usually with bulk handling techniques. These processes expose workers to the radioactivity in the materials, therefore, workers would incur radiological risks in addition to industrial accident risks. An important question is whether the potential reduction of future radiological risks to members of the public justifies the risks that are incurred by remediation workers due to handling materials. This study examines, first, the effectiveness of treatment and then the risks that would be associated with remediation

The influence of age at time of exposure to 226Ra or 239Pu on distribution, retention, postinjection survival, and tumor induction in beagle dogs

International Nuclear Information System (INIS)

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

1991-01-01

The influence of age at injection of 226Ra or 239Pu on skeletal deposition and local distribution, the pattern of bone tumor formation, and postinjection survival was assessed in parallel short-term studies of mechanisms and lifetime toxicity. Beagles received a single intravenous injection of 226Ra or 239Pu at 3 months (juveniles), 17-19 months (young adults) or 60 months (mature). Data from short-term studies of mechanisms and dosimetry and from one dosage level of each of the toxicity experiments were compared. Skeletal growth and turnover produced differential initial deposition and distribution patterns typical for each age group. At 1 week after injection, skeletal retention of 226Ra or 239Pu was 68 and 68%, respectively, in the juveniles, 32 and 46% in the young adults, and 31 and 43% in the mature dogs. Comparing individual bones in the juveniles, gradients in the concentration of 239Pu were small since all bones were actively growing, but substantial gradients, corresponding to centers of ossification, were present within individual bones. In other age groups, local concentration gradients were less pronounced, but much larger differences were present among the various bones. In the toxicity study all animals injected with either 41 kBq 226Ra/kg or 11 kBq 239Pu/kg have died. The cumulative average skeletal doses to the presumed time of start of tumor growth (1 year before death) were 25 and 4 Gy, respectively, for the juveniles, 22 and 5 Gy for the young adults, and 15 and 4 Gy for the mature dogs. The highest bone tumor incidence was seen in the young adult groups. Differences were observed in location of bone tumors between dogs in the same age group given radium or plutonium and among age groups injected with either radionuclide, some of which could be explained by differences in local dose distributions

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Development and validation of a fast combined analysis method for the determination of the natural radioisotopes Pb-210, Po-210, Ra-226, Ra, 228, U-234 and U-238 in drinking water

International Nuclear Information System (INIS)

Schuster, Martina

2015-01-01

The guiding value of the effective dose for the consumption of drinking water is 0.1 mSv per calendar year. For the purpose of dose assessment the intake of all relevant radio nuclides via drinking water has to be determined. Some analysis methods for the determination of relevant natural occurring radio nuclides are published but they need complete different and time consuming analysis methods for each radionuclide. This study shows an analysis method which is able to determine the radio nuclides 210 Pb, 210 Po, 226 Ra, 228 Ra, 238 U and 234 U quantitatively within a justifiable time scale. It is based on a chromatography method which has been validated for determination of 90 Sr and 89 Sr in milk, vegetable food and human and animal bones respectively. Applying this method the elution ranges for lead and polonium are so different from uranium and radium that a combined separation with high chemical yield is possible, even by miniaturization the chromatography column which means significant time saving. The activity concentration of 228 Ra and 226 Ra is determined applying gamma-spectrometry and that of 210 Pb, 210 Po, 234 U and 238 U by LSC. The chemical yield of 210 Pb is calculated with a stable lead applying AAS and that of the radium isotopes with 223 Ra. Therefor 223 Ra is separated of a 227 Ac standard solution. The method is validated by a interlaboratory test for the determination of natural radio nuclides in drinking water which was released by the Bundesamt fuer Strahlenschutz. For the analysis only about four litres of drinking water are necessary to realize the required limit of detection. The method is very efficient, enough specific and allows the determination of dose relevant radio nuclides.