Determination of <Superscript>3</Superscript>H, <Superscript>226</Superscript>Ra, <Superscript>222</Superscript>Rn and <Superscript>238</Superscript>U in Austrian ground- and drinking water

Screening measurements for ³H, ²²⁶Ra, ²²²Rn and ²³⁸U in ground water were performed within a ground- and drinking water project in Austria. The aim of this project is to get an overview of the distribution of natural radionuclide activity concentration levels in ground water bodies. In some cases this water is used for drinking water abstraction. In this paper methods and results of the screening measurements are presented. Regions with high activity concentrations were identified and in these regions further investigation for ²²⁸Ra, ²¹⁰Pb and ²¹⁰Po will be conducted.     

Effective doses due to intake of radiotoxic radionuclides 226Ra, 210Po and 210Pb through drinking water of coastal Karnataka

The concentrations of ²²⁶Ra, ²¹⁰Po and ²¹⁰Pb have been measured, by high efficiency 5″ × 5″ NaI(Tl) gamma ray spectrometer and chemical deposition method, in surface water samples from major rivers Kali, Sharavathi and Netravathi of coastal Karnataka. Measurements of ²²⁶Ra, ²¹⁰Po and ²¹⁰Pb in surface water from these rivers are important because the river water is main source of potable water in this region due to inadequate supply of treated water. The mean activity of ²²⁶Ra, ²¹⁰Po and ²¹⁰Pb in the surface water of the river Kali was found to be 5.13 mBq L⁻¹, 1.28 and 1.37 Bq L⁻¹, for Sharavathi River the mean activity was found to be 3.37 mBq L⁻¹, 1.30 and 1.44 Bq L⁻¹. In Netravathi River the mean activity of ²²⁶Ra, ²¹⁰Po and ²¹⁰Pb was found to be 3.30 mBq L⁻¹, 1.00 and 1.20 Bq L⁻¹. From the measured concentration of ²²⁶Ra, ²¹⁰Po and ²¹⁰Pb, the Effective dose to the population of the region was computed. The results of these systematic studies are presented and discussed in the paper.     

Calibration and optimization of alpha-beta separation procedures for determination of radium/radon in single- and two-phase liquid scintillation systems

Liquid scintillation alpha beta discrimination technique based on pulse shape analysis (PSA) was evaluated for determination of ²²⁶Ra and ²²²Rn in water samples. In view of the significance of calibration, for the reliable and precise determination of ²²⁶Ra and ²²²Rn concentrations in water samples, calibration procedures were standardized for single and two phase systems using Quantulus 1220 liquid scintillation counter. PSA optimization and efficiency calibrations were performed using ²²⁶Ra standard rather than conventionally used pure alpha and beta standards and substantiated by measuring the activity concentrations of ²²⁶Ra and ²²²Rn in the spiked water samples.     

Determination of 210Pb, 210Bi and 210Po in natural drinking water

A new method for the radioanalytical determination of the ²²²Rn progenies ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Powill be presented, which has been improved for analyses of water samples fromdifferent regions in Austria. 1–2 liter samples were taken in polyethylenebottles prefilled with conc. HNO₃ to obtain 0.2M acidic solutions,thus avoiding adsorption effects. After adding 1.6 mg of inactive lead carrier,the water sample was evaporated to dryness, converted to the chloride formand dissolved in 1M HCl.     

Two new methods of determining radon diffusion in fish otoliths

Otoliths are bony structures found in the ears of fish and used in the²¹⁰Pb/²²⁶Ra dating method for age determination. This paper checks the assumption that²²²Rn is not lost from or added to orange roughy fish otoliths by diffusion, which would invalidate the technique. The first method of monitoring diffusion relies on measuring the gamma activity of daughter radionuclides. Otoliths were exposed to an atmosphere enriched in²²²Rn for 10 days, and the supported gamma activity inside them measured allowing for various decay corrections. The calculated radon addition was (0.5±0.5)% of the activity of the²²⁶Ra present. The second method used an alpha spectrometer and attempted to detect²²²Rn directly outgased from otoliths in the detector vacuum chamber. The results were consistent within errors with those of the first method and showed no loss or gain of²²²Rn, supporting previous estimates of a long life-span for the orange roughy. In contrast it was found that approximately 10% of²²²Rn formed in orange roughy fish scales was lost to an evacuated environment, (hence perhaps to an aqueous environment) and that for this species it could be difficult to base a dating method on analysis of scales. Nevertheless a preliminary minimum age of 57 years was obtained. The methods could be used with non-biological samples to determine²²²Rn diffusion rates.     

Estimation of sedimentation rates using 210Pb and 210Po at the coastal water of Sabah, Malaysia

Sediment cores were obtained from Teluk Brunei, Sipitang, Teluk Kimanis, Kota Kinabalu and Kuala Penyu at the coastal water of Sabah and analyzed for ²¹⁰Pb and ²¹⁰Po to estimate the sedimentation rates. The calculated sedimentation rates of ²¹⁰Pb and ²¹⁰Po varied from 0.003 to 0.049 cm/y and 0.74 to 8.77 cm/y, respectively. The highest sedimentation rates were determined for ²¹⁰Pb and ²¹⁰Po at stations located at Sipitang (mean: 0.027 cm/y) and Teluk Kimanis (mean: 5.53 cm/y), respectively. The sedimentation rate estimated for ²¹⁰Pb is not fully reliable because the activity of ²²⁶Ra was higher than that of ²¹⁰Pb and bioturbation was active at the sampling stations.     

Measurement of 222Rn and 226Ra in municipal supply tap water to evaluate their radiological impacts

ABSTRACT

Radon (²²²Rn) and its parent radionuclide Radium (²²⁶Ra) are classified as carcinogen. Human exposes to radon in water via inhalation and ingestion, although ingestion is the only way for radium to enter the human body. In this research, tap water collected from Bornova distinct was studied to determine the concentration of radon (²²²Rn) and radium (²²⁶Ra) for evaluating their radiological impact. For this reason, the annual effective doses for ingestion and inhalation were estimated. The measurements were performed using a collector chamber method. The mean concentrations of ²²²Rn and ²²⁶Ra were determined as 0.85 and 0.76 Bq/L, respectively. It can be stated that the ²²²Rn and ²²⁶Ra concentrations of tap waters here are lower than the international reference levels. Obtained concentration levels were applied to estimate annual effective dose due to the inhalation and ingestion. The dose values are also found to be lower than the recommended maximum values. On the other hand, it should be considered that consumption of these waters (2 L) and average radon and radium concentrations of water are the significant factors for estimating doses.     

Study of the Energy Resolution in Alpha-Particle Spectra from Electrodeposited Radium Sources

Electrodeposited ²²⁶Ra sources were prepared and measured in order to perform a detailed study of the energy resolutions attained with two recent electrodeposition procedures for preparing spectrometric radium sources. The values of the energy resolution for the high-energy emission of ²²⁶Ra and for the single-emissions of ²¹⁰Poand ²²²Rn were calculated by fitting the data with a curve formed by the convolution of two left-handed exponentials with a Gaussian function. Significant differences between the energy resolutions for the aforementioned radionuclides were observed. The ²¹⁰Po energy resolutions were, in general, somewhat better than those obtained for ²²⁶Ra. On the contrary, the energy resolutions found for ²²²Rn were notably poorer than those obtained for ²²⁶Ra and ²¹⁰Po. These discrepancies can be satisfactorily explained by taking into consideration the distribution of these nuclides in the sources and the effect of radon diffusion involved in this type of thin deposit.     

Comparison of transfers for natural radionuclides (238U, 234Th, 226Ra, 210Pb & 210Po) from five different soils to four different barley genotypes

Transfer Factors (Fv) of ²³⁸U, ²²⁶Ra, ²³⁴Th, ²¹⁰Po and ²¹⁰Pb from five different agricultural soils in semi-arid region (Syria) to four different barley genotypes were studied in an agricultural potted experiment. The geometric mean of the Fv values were (0.08) for ²¹⁰Pb, and (0.02) for ²¹⁰Po, while it ranged from 0.18 to 0.42 ,from 0.08 to 0.15 and from 0.22 to 0.4 for ²³⁸U, ²³⁴Th and ²²⁶Ra, respectevily. The Fv values of ²³⁸U and ²²⁶Ra were within the recommended global medians, while the Fv values of ²³⁴Th, ²¹⁰Pb and ²¹⁰Po were higher. There is no clear relationship between the soil properties and Fv of all studied radionuclides to barley genotypes. Moreover, the expression of glutathione (GSH) gene, which is belived to be involoved in heavy metal removal was generally low in all studied varieties grown in all soil types.

     

Determination of neodymium isotopes as burnup indicator of highly irradiated (U,Pu)O2 lmfbr fuel

A new counting method was developed to determine²²⁶Ra in environmental samples by separating the equilibrated²²²Rn into a liquid scintillator. The integral counting method, which was originally developed for isolated individual radionuclides, was extended to the mixture of²²²Rn and its daughters in equilibrium. The optimum measurement conditions were established by examining the energy spectrum, counting time and quenching effect. An absolute counting was practiced by extrapolating the integral counting rate-bias voltage curve with the highest gain to zero bias. The detection limit thus obtained was 3 to 4·10⁻¹³ Ci.     

226Ra, 228Ra and 210Pb Isotopes in Some Water Samples of Mines

A method for the determination of ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb in water samples of mining regions by measuring the and intensities with the help of a liquid scintillation counter is presented. The high-energy part of the -particle spectrum emitted by ²¹⁰Bi is used for the determination of ²¹⁰Pb content in the samples. An attempt is also given to explain the radioactive disequilibrium between ²²⁶Ra and ²¹⁰Pb in the samples investigated.     

Non-destructive determination of low-level210Pb and226Ra with an ordinary high-purity Ge-detector

A convenient non-destructive method for the determination of low level²¹⁰Pb and²²⁶Ra with an ordinary high-purity Ge-detector is presented. The ordinary Ge-detectors used in this work were available to measure 46.5 keV -rays of²¹⁰Pb. These detectors were also useful for the non-destructive analysis of low-level²²⁶Ra in lime-stone and calcium chemicals when a stream of nitrogen gas was maintained around the detectors. By this method, measurements could be carried out not only for²¹⁰Pb and²²⁶Ra but also for other -emitting radionuclides simultaneously, using the same detector. The detection limits of about 1 Bq per sample for²¹⁰Pb and about 0.05 Bq per sample for²²⁶Ra, respectively, were estimated, when the samples were counted for 1–2 days.     

Studies on226Ra and210Pb activities and the concentration factors of226Ra in the surface organic layers of the estuarine sediments of Mindola and Purna rivers in India

The sediment samples have been collected from estuarine regions of Mindola and Purna of Gujarat State. These samples are found to contain less than 3% of organic matter which scavange and carry most of the activity of²²⁶Ra, etc., to the sediment floor. The activities of²²⁶Ra are found to vary from 0.1 to 0.5 pCi/g, while²¹⁰Pb 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 consumed by humans. This paper gives in detail the sampling techniques, experimental procedures and the distribution of the isotopes of²²⁶Ra and²¹⁰Pb in the estuarine regions and the concentration factors of²²⁶Ra in the region.     

Solvent extraction of uranium(VI) with benzyloctadecyldimethylammonium chloride (BODMAC) from highly concentrated chloride solution

The ²²²Rn emanation fraction (EF) released from the technically enhanced naturally occurring radioactive material (TE-NORM) wastes at certain sites of petroleum and gas production was determined. The samples were analyzed by γ-ray spectrometry to determine the activity concentration of the ²²⁶Ra content, of which the ²²²Rn emanation fraction was calculated. The results showed that the ²²²Rn emanation fraction differs in the oil and gas production sites and it is independent of the activity concentration of ²²⁶Ra. This revised version was published online in August 2006 with corrections to the Cover Date.     

Natural radioactivity of geothermal water in Beijing,China

In this work, we collected 101 geothermal water samples to investigate comprehensively the radioactivity of geothermal water in Beijing. The concentrations of gross beta, ²²⁶Ra and ²²²Rn were measured and the obtained values were in the range of 0.032–7.060, 0.023–0.363 and 0.470–29.700 Bq/L, respectively. The samples with higher concentration of ²²²Rn were found to be located near large faults. The effective dose of ²²²Rn in the air for three cases were calculated to be greater than radiation dose limit of 1 mSv/a.     

Vertical inventories and fluxes of <Superscript>210</Superscript>Pb, <Superscript>228</Superscript>Ra and <Superscript>226</Superscript>Ra at southern South China Sea and Malacca Straits

Inventories and fluxes of ²¹⁰Pb, ²²⁸Ra and ²²⁶Ra were determined in sediment cores collected at nine stations covering of the southern South China Sea and Malacca Straits with the thickness of water column between 42 and 83 m depth. The inventories of ²¹⁰Pb, ²²⁸Ra and ²²⁶Ra were calculated range from 0.15–2.55 Bq cm⁻², 0.05–0.40 Bq cm⁻² and 6.83–83.63 Bq cm⁻², meanwhile the fluxes ranged from 0.005–0.079 Bq cm⁻² yr⁻¹, 0.009–0.048 Bq cm⁻² yr⁻¹ and 0.003–0.037 Bq cm⁻² yr⁻¹, respectively. The results show that the highest inventories and fluxes for ²¹⁰Pb, ²²⁸Ra and ²²⁶Ra were found at station WC 01 and EC 05. Because there are additional sources of ²¹⁰Pb, ²²⁸Ra and ²²⁶Ra, where water transport will brings more dissolved isotopes, influence of the transportation and deposition of suspended particles, fast rate of regeneration and greater production of those radionuclides and others.     

Direct determination of 226Ra in NORM/TENORM matrices by gamma-spectrometry

Summary The main shortcoming with the procedure to determine ²²⁶Ra in a gamma spectrum of an environmental sample by means of the ²¹⁴Bi and ²¹⁴Pb photopeaks is the likelihood of ²²²Rn leakage from the sample counting vial. An option to make such determination is to disregard the ²²⁶Ra gamma-contributions to the spectrum, other than 186.2 keV (3.5%), subtracting the ²³⁵U contribution to the ²²⁶Ra+²³⁵U peak at 186 keV. The use of this option to determine directly ²²⁶Ra activity concentrations in environmental samples and in NORM/TENORM matrices will be presented and discussed.     

210Pb fluxes in sediment layers sampled from Northern Patagonia lakes

Unsupported ²¹⁰Pb fluxes were determined from sediment core inventories in lakes located in Northern Patagonia, Argentina. Total ²¹⁰Pb, ²²⁶Ra, associated with supported ²¹⁰Pb, and ¹³⁷Cs specific activity profiles were measured by gamma-ray spectrometry. Unsupported ²¹⁰Pb fluxes showed very low values when compared to other regions, with a 12 fold variation, ranging from 4 to 48 Bq m^–2.y^–1. The linear correlation observed between the ²¹⁰Pb fluxes and¹³⁷Cs cumulative fluxes in sediment cores sampled from water bodies within a zone with similar precipitation demonstrated that both radioisotopes behave in the same manner in these systems concerning the processes occurred from fallout to sediment deposition, and that there are no appreciable local or regional sources of unsupported ²¹⁰Pb. Positive correlation of ²¹⁰Pb fluxes with organic matter contents of the uppermost sediment core layers was also observed.     

Vertical distribution of <Superscript>210</Superscript>Pb and <Superscript>226</Superscript>Ra and their activity ratio in marine sediment core of the East Malaysia coastal waters

Marine sediment cores were collected from two stations at East Malaysia coastal waters on June 2004. Activity concentrations of ²¹⁰Pb in sediment core were ranged from 11 Bqkg⁻¹ to 84 Bqkg⁻¹ dry wt. for SR 01 and 4 Bqkg⁻¹ to 66 Bqkg⁻¹ dry wt. for SB 03. Meanwhile, activity concentrations of ²²⁶Ra in sediment core were varied significantly depending on the sampling location of SR 01 and SB 03 with ranged 17–26 Bqkg⁻¹ dry wt. and 8–11 Bqkg⁻¹ dry wt., respectively. The activity ratios of ²¹⁰Pb/²²⁶Ra were no significantly different at all sampling stations with an average of 1.78. Refer to the entire results; the activities of ²¹⁰Pb and ²²⁶Ra were higher at station SR 01 than station SB 03, but contrast with ratio of ²¹⁰Pb/²²⁶Ra. The reasons of different ²¹⁰Pb and ²²⁶Ra activity concentration and distribution of their ratios were strictly related to their half lives, environment origin, potential sources and behavior.     

226Ra and 222Rn concentrations of spring waters in Balaton Upland of Hungary and the assessment of resulting doses

²²²Rn and ²²⁶Ra concentration of 18 frequently visited and regularly used, consumed spring waters on the Balaton Uplands have been measured by radon emanation method and alpha-spectrometry. ²²²Rn concentration varied between 1.5-55 Bq/l while ²²⁶Ra concentration between -601 mBq/l. The expected dose, between 14.1-119 mSv/y, has been assessed from the value of concentration supposing a daily consumption of 1 liter.