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1.
A study of the physical state of226Ra in uranium mill tailings was undertaken by Chemex Laboratories Ltd. under contract to NUTP. A test portion of a leached uranium ore was collected just prior to neutralization with lime and subjected to repetitive batch water leaching. The leachates were analyzed for barium, lead,226Ra, iron and sulphate. The experimental results suggest that226Ra is co-precipitated with lead sulphate during uranium leaching of the ore with sulphuric acid. The attainment of equilibrium conditions in the pore water of the leached ore then allows a re-proportioning of226Ra between solid lead and barium sulphates resulting in a depletion of226Ra in the outer layers of the crystals of solid lead sulphate and an enrichment in226Ra in the outer layers of solid barium sulphate. 相似文献
2.
I. Chereji 《Journal of Radioanalytical and Nuclear Chemistry》1992,165(4):263-267
A comparison between the counting parameters of solid and liquid scintillation methods for radon determination in water is attempted. The counting efficiency is better for a toluene-based liquid scintillator but, as the background is considerably higher than in solid scintillators, the figure of merit and the lower limit of the measurable activity are favorable for a scintillation counter based on zinc sulfide (Ag activated) scintillator. 相似文献
3.
Liquid scintillation counting (LSC) and pulse shape analysis (PSA) was used in measuring radon and gross alpha- and beta-activities in groundwater. We used conventional LSC counters for the measurement of radon in water, but low-background LSC spectrometers for the gross activity measurements. The lower limit of detection (LLD) for radon in water is 0.6 Bq/l for a 60 min count with a conventional counter, but 0.1 or 0.2 Bq/l, with the two types of low-background LSC spectrometers equipped with a pulse shape analyser (PSA). The gross alpha and beta activity measurements are made using a simple sample preparation method, PSA of a low background LSC and spectrum analysis. The LLD recorded for gross alpha and beta with the two spectrometers are 0.02 and 0.03 Bq/l and 0.2 and 0.4 Bq/l, respectively, for a 180 minutes count and a 38 ml sample volume. The method also enable the calculation of the U and226Ra contents in water and indicates the presence of some other long-lived radionuclides (210Pb,228Ra or40K). The LLD for U recorded with both spectrometers is 0.02 Bq–1 and for226Ra 0.01 Bq·1–1. The LLDs attained by this LSC method are two orders of magnitude lower than the maximum permissible concentrations set for U and226Ra. 相似文献
4.
Alomari Ahmad Hussein Saleh Muneer Aziz Hashim Suhairul Alsayaheen Amal Abdeldin Ismael 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):305-318
The activity concentrations of 226Ra, 228Ra and 222Rn were measured in 87 groundwater samples to estimate the activity concentrations of these radionuclides and health impact due to intake of these radionuclides in groundwater of Jordan. The mean activity concentrations of 226Ra, 228Ra and 222Rn in groundwater were found to be 0.293?±?0.005 Bq L?1, 0.508?±?0.009 Bq L?1 and 58.829?±?8.824 Bq L?1, respectively. They give a mean annual effective dose of 0.481 mSv with mean lifetime risk of 24.599?×?10?4, exceeding the admissible limit of 10?4. Most of the received annual effective dose (59.15% of the total) is attributed to 228Ra.
相似文献5.
Mutlu İçhedef 《International journal of environmental analytical chemistry》2013,93(11):1069-1077
ABSTRACTRadon (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. 相似文献
6.
T. Kovacs E. Bodrogi J. Somlai V. Jobbágy G. Patak Cs. Nemeth 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(1):191-194
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. 相似文献
7.
Tadeusz A. Przylibski Joanna Gorecka Agata Kula Lidia Fijałkowska-Lichwa Katarzyna Zagożdżon Paweł Zagożdżon Wojciech Miśta Robert Nowakowski 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(3):757-764
Since 2008, the authors have been conducting research into 222Rn and 226Ra activity concentrations in shallow circulation groundwaters in southern Poland. Measurements have been performed with a liquid-scintillation method and ultra low-level liquid-scintillation spectrometers α/β Quantulus 1220. The research carried out so far has demonstrated that in the Sudetes groundwaters with high activity concentrations of 222Rn and 226Ra are common. In other studied areas in southern Poland no shallow circulation groundwaters with high radon or radium concentrations have been found yet. The conducted research has demonstrated that the activity concentration of 222Rn dissolved in shallow circulation groundwaters in the Sudetes depends chiefly on the amount of radon, which after being released as gas from reservoir rocks is dissolved in waters flowing through these rocks. At the same time, the concentration of 222Rn dissolved in some shallow circulation groundwaters in the Carpathians is influenced significantly by the amount of radon produced from the decay of its parent ion 226Ra2+ dissolved in these waters. 相似文献
8.
Nisar Ahmad Tabassum Nasir Sohail Rizwan Hamid Ullah Muhammad Bakhsh 《International journal of environmental analytical chemistry》2019,99(7):683-691
Lucky Cement Factory, Pezu is using limestone of Sheikh Buddin Hills as a raw material in cement. Workers of the factory have direct and general public have indirect exposure to radiological hazard due to natural radionuclides present in limestone. To address the radiological hazards, limestone, mixed (limestone+clay) and cement samples were evaluate for concentrations of 222Rn and 226Ra using CR-39, RAD7 and HPGe detectors. Maximum mean values of 222Rn using CR-39 and RAD7 detectors were found 1447 ± 198 and 1416 ± 74 Bq.m?3 in cement samples and minimum were found in 536 ± 122 and 525 ± 45 Bq.m?3 limestone samples, respectively. Maximum mean value of radon exhalation rate of 12.28 ± 1.68 Bq.m?2 h?1 in cement samples was found below the world average value of 57.6 Bq.m?2 h?1. Maximum mean values of 226Ra measured by CR-39 and HPGe detectors were found 24.25 ± 3.35 and 23.6 ± 0.70 Bq.kg?1 in cement samples and minimum were found in 8.98 ± 2.02 and 9.19 ± 0.40 Bq.kg?1 limestone samples, respectively. A positive correlations (R2 = 0.9714) using CR-39 and RAD7 detectors and (R2 = 0.9573) using CR-39 and HPGe detectors were obtained for the concentrations of 222Rn and 226Ra, respectively. Maximum mean value of annual effective dose of 347.78 ± 47.58 µSv.y?1 in cement samples was found below the world average value of 1100 µSv.y?1. 相似文献
9.
X. N. Yang W. Y. Zhou R. S. Wang 《Journal of Radioanalytical and Nuclear Chemistry》1995,198(2):281-285
A study of the immobilization for226Ra waste has been carried out. Cement-based concrete was used as a matrix for the solidification of radium waste. The experimental results show that the cement mixture with water/cement between 0.46–0.54 has higher strengh (above 20 MPa), and the compressive strength was not reduced by addition of 1% barite or the radium waste (RaSO4) into the concrete solid.Sponsored by the National Nuclear Corporation of China. 相似文献
10.
Mei-Wo Yii Zal Uyun Wan-Mahmood 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):1465-1472
Surface sediment samples were collected at the West (east coast and west coast of Peninsular Malaysia) and East (Sabah and Sarawak) Malaysia in several expeditions within August 2003 until June 2008 for determining the level of natural radium isotopes. Activity concentrations of 226Ra and 228Ra in surface marine sediment at 176 sampling stations were measured. The activity concentrations of both radionuclides in Malaysia (East and West Malaysia) display varied with the range from 9 to 158 Bq/kg dry wt. and 13 to 104 Bq/kg dry wt., respectively. Meanwhile, the ratio distributions of 228Ra/226Ra were ranged from 0.62 to 3.75. This indicated that the ratios were slightly high at west coast of Peninsular Malaysia compared to other regions (east coast of Peninsular Malaysia, Sabah and Sarawak). The variation of activity concentrations of 226Ra and 228Ra and its ratios were also supported by the statistical analyses of one-way ANOVA and t test at 95 % confidence level, whereby there were proved that the measured values were different between the regions. These different were strictly related to their half-life, potential input sources (included their parents, 238U and 232Th), parent’s characteristic, the geological setting/formation of the study area, environment origin and behavior. 相似文献
11.
The evaluation of the source term in facilities related to the first stages of nuclear fuel involves the determination of radium concentration, as well as those from other radionuclides members of the uranium series. These activities are often required within a short time period, making impossible the use of radiochemical methods or the gamma-ray spectrometry of radium daughters. In those situations it can be very convenient to determine the226Ra activity by means of its 186 keV gamma-ray line. For this purpose it is necessary to estimate the interference due to235U, also present in natural samples. This method has been applied successfully to several soil samples from an old uranium factory in Southern Spain. 相似文献
12.
Copia Lorenzo Plastino Wolfango Nisi Stefano Ciarletti Marta Povinec Pavel P. 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(1):385-393
Journal of Radioanalytical and Nuclear Chemistry - Groundwater samples, collected into the deep underground facilities of Gran Sasso National Laboratory of the National Institute of Nuclear Physics... 相似文献
13.
L. Stoica D. Filip Gh. Filip A. Razvan R. Radulescu 《Journal of Radioanalytical and Nuclear Chemistry》1998,231(1-2):139-142
The activity of137Cs was determined in mosses and their surrounding soils in three Venezuelan cloud forests. The concentration of137Cs in both the mosses and their respective soils were correlated with elevation (m.a.s.l.). This relationship was the result
of the cloud forest effect, no direct deposition by condensation below the base of the clouds and increasing deposition of137Cs with the density of the clouds. The ratio of the activity of137Cs in the mosses to their surrounding soils was in general the same for sites near the top of the mountains, but the ratio
at the Altos de pipe location was 3.5 times higher than that of the La Sierra mountain. This was explained by the difference
in the water content of the surface and the top soil layer. It was concluded that the137Cs measured in the mosses was from the soil effect rather than new deposition of137Cs in the last three years. 相似文献
14.
Zal U’yun Wan Mahmood Mei-Wo Yii 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(1):183-192
The present occurrence of 226Ra and 228Ra in marine sediment core and fish from the Exclusive Economic Zone in the east coast of Peninsular Malaysia were studied.
Sediment core and biota in respectively was collected using multicorer device and purchased from local fishermen at identified
stations during the cruise expedition conducted in 2008. The purpose of this study was to determine and to make available
an inventory of activity concentration levels and activity ratio for these radionuclides in this region. The activity concentrations
of 226Ra and 228Ra in sediment core and edible part of fish were ranged between 15.9–46.5 and 27.7–87.1 Bq/kg dry wt and; 0.80–2.13 and <0.95–3.57 Bq/kg fresh
wt, respectively. Meanwhile, the activity ratios of 228Ra/226Ra in sediment core and fish were varied with the range between 1.63–2.09 and 0.45–2.38, respectively. Refer to those ranges
the activity concentrations of radium isotopes were comparable with other region. Thus, it can be concluded that the occurrence
of radium isotopes mainly supplied from terrestrial sources and the factors of assimilation efficiency and transfer coefficient
of radium may probably effect to the variation activity concentration of 226Ra and 228Ra and its activity ratio in edible part of pelagic and demersal fish obtained in this study. 相似文献
15.
A procedure for the determination of natural uranium and226Ra in waters and soils has been carried out and applied to the analysis of samples for environmental radiological monitoring.226Ra determination consists of co-precipitation with BaSO4,222Rn emanation in toluene and finally liquid scintillation counting. Natural uranium is then determined by a fluorometric technique. This paper describes the method and the conditions that were tested to optimize it. The technique was found to be suitable for the analysis of surface and ground waters, samples from rivers, streams and lakes and soil samples, because of its few steps, short processing time, high recovery percentages and suitable detection limits. 相似文献
16.
N. E. Whitehead R. G. Ditchburn W. J. McCabe R. Van Der Raaij 《Journal of Radioanalytical and Nuclear Chemistry》1992,160(2):477-485
The electrodeposition of226Ra for -spectrometry was reinvestigated to improve reproducibility and yield. Electrodeposition is from 20 ml of 90% propan-2-ol10% 0.05M HNO3 onto stainless steel disks, using 100 mA at 35 V for 20 minutes and a platinum anode. Half deposition time is 3–4 minutes. The following factors were found important: 1. Maintaining the same anode position. 2. Rotation of cathode. 3. Exclusion of sulphate. 4. Avoiding heating the HNO3/propan-2-ol plating solution. 5. Exclusion of solubilised resin resulting from passage through ion-exchange columns. 6. Maintaining other impurities at less than 10 g. If these precautions are followed yields are greater than 90%. 相似文献
17.
The most commonly available 226Ra determination was too time-consuming to be suited to 226Ra monitoring for the accidental release. The formula for determination of 226Ra was derived by 224Ra correction for WHO's equation. A rapid determination of 226Ra in environmental materials was made possible by using this formula. The 226Ra values of the soil and natural water at Ningyoh-Tohge obtained by the present method were in good agreement with those by the conventional WHO method. It was demonstrated that 226Ra of more than about 37 mBq (1 pCi) in the sample could be determined within 4 days by this method. 相似文献
18.
K. G. Ioannides C. Papachristodoulou D. T. Karamanis K. C. Stamoulis T. J. Mertzimekis 《Journal of Radioanalytical and Nuclear Chemistry》1996,208(2):541-547
The concentration of radon (222Rn) was measured in the soil near the ground surface, using CR/39 solid state nuclear track detectors. The measurements were carried out in PVC tubes at 0.25 m intervals up to 1.25 m. The detectors were etched in 7N NaOH solutions at 80°C. The -tracks from radon's decay were counted using a microscope. A microscope-camera-computer system developed for automatic counting was also used. The results provide evidence for the non-diffusive transport of radon in soils. A transport length of (46.9±3.2) cm was estimated for radon transport near ground surface. Also the variation of soil's radon concentration was correlate to humidity and atmospheric pressure. 相似文献
19.
E. R. Landa 《Journal of Radioanalytical and Nuclear Chemistry》2003,255(3):559-563
Specific extraction studies in our laboratory have shown that iron and manganese oxide- and alkaline earth sulfate minerals are important hosts of radium in uranium mill tailings. Iron- and sulfate-reducing bacteria may enhance the release of radium (and its analog barium) from uranium mill tailings, oil field pipe scale [a major technologically enhanced naturally occurring radioactive material (TENORM) waste], and jarosite (a common mineral in sulfuric acid processed-tailings). These research findings are reviewed and discussed in the context of nuclear waste forms (such as barium sulfate matrices), radioactive waste management practices, and geochemical environments in the Earth's surficial and shallow subsurface regions. 相似文献
20.
The analysis of 226Ra in natural waters can be tedious and time-consuming. For the determination and differentiation of activities of 226Ra and 222Rn in drinking water by γ-ray spectrometry a simple and fast method is presented. Activities of 226Ra > 0.5 Bq L−1 can be determined according to stabilization of the sample without further procedures. For a more sensitive detection sample
volumes of up to 5 litres are applicable by a rapid precipitation procedure without large expenditure. Further laborious enrichment
methods are not necessary. Thus, detection limits of 0.1 Bq L−1 can be obtained when using sample volumes of 5 litres. Therefore the method is suitable for the monitoring of radioactivity
in drinking water samples in accordance with the legal guidance of the European Union. 相似文献