Method for detecting and characterising actinide-bearing micro-particles in soils and sediment of the Fukushima Prefecture,Japan

An aqueous biphasic system has been used for selective extraction of U(VI) ions from Th(IV), Sm(III) and Ce(III). Role of different biomolecules like morin, catechin, hesperidin and 4-hydroxycoumarin have been studied. Morin serves as the best reagent when citrate ions are used as a masking agent. Citrate forms stronger complexes with the other metal ions than morin thereby restricting their extractions. Contrarily, U(VI) forms a stronger complex with morin than citrate and is selectively extracted under the same conditions. It was also observed that morin can act as a spectrophotometric reagent for ratiometric detection and analysis of U(VI) ions.

     

Effect of moisture content on the 222Rn mass exhalation rates for different grain-size samples of red brick and cement mortar used in Qena city,Egypt

Journal of Radioanalytical and Nuclear Chemistry - Four different grain size fractions (0.2–0.5, 0.5–1, 1–1.8, 1.8–2 mm) of red brick and cement mortar samples at...     

Radiological assessment of 222Rn, 220Rn,EERC, and EETC in residential dwellings of district Palwal,Southern Haryana,India

Journal of Radioanalytical and Nuclear Chemistry - A systematic measurement of radon/thoron concentration by using pin-holes dosimeter and their decay products by deposition based progeny sensors...     

Evaluation of 222Rn and 226Ra concentrations in cement and limestone of Sheikh Buddin Hill,Pezu, Pakistan using different techniques

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.     

Annual effective dose due to 222Rn and evaluation of 238U, 232Th and 40K contents in soil at the south-eastern coastal area of Bangladesh

Journal of Radioanalytical and Nuclear Chemistry - On-site 222Rn concentration at three different soil depths was measured at the south-eastern coastal area of Bangladesh to evaluate the annual...     

CFD-based simulation and experimental verification of 222Rn distribution in a walk-in type calibration chamber

A walk-in type ²²²Rn calibration chamber (~ 22 m³) is established at the Centre for Advanced Research in Environmental Radioactivity (CARER), Mangalore University, India which is being used by research groups working on ²²²Rn in India and other countries as well. In recent times, computational fluid dynamics (CFD) technique is opted as an alternative approach for the prediction of ²²²Rn concentration profile in the closed domain. CFD simulations were carried out to study the transient build-up and spatial behavior of ²²²Rn concentration in the calibration chamber. Measurements were performed using active ²²²Rn measuring devices and results of the CFD predictions and direct measurements were compared. A good agreement was observed between the simulated and experimental results with deviation between the two entities being ~ 3% in the case of transient build up and ~ 8% in the case of spatial distribution of ²²²Rn concentration.

     

A study of 222Rn concentration of salty underground water and spring water in Jeju,Korea

Journal of Radioanalytical and Nuclear Chemistry - The efficiency transfer procedure from a geometry where a volume source was placed directly on the endcap of a germanium detector to three...     

Temperature variations and amyloglucosidase levels at different bed depths in a solid state fermentation system

Studies on moist wheat bran medium, inoculated with Aspergillus niger CFTRI 1105, indicate steep gradients in the temperature and enzyme levels at different depths in deep bed rectangular fermenters with different loads. An increase of about 2.5 °C over a bed depth of 40 mm in a fermenter with a load of 49.7 kg m⁻² was due to metabolic heat generation in the initial fermentation period. This was found to result in a doubled fermentation time to attain enzyme levels which were comparable, although still lower by 4.6%, with those in a fermenter with a load of 17.8 kg m⁻². The temperature variations were about 10–18 °C for a bed depth of 80 mm and the highest enzyme levels were lower by 23.4%, even after 48 h, with a load of 49.7 kg m⁻² compared with those for a load of 17.8 kg m⁻² . The metabolic heat and enzyme biosynthesis functions were found to be significantly affected by an increase in bed depth. The maximum temperature variations recorded in the fermenter with a load of 126.1 kg m⁻² were 19.5 °C at 12 h and 21.2 °C at 60 h for 80 and 160 mm bed depths respectively. Consequently, the maximum enzyme levels were lower by 81%–86% and required a 2.5-fold increase in fermentation time compared with a fermenter with a load of 17.8 kg m⁻².The results indicate that the temperature gradients play a key role in the biosynthesis of the enzyme in a solid state fermentation system involving deep beds.     

Use of 222Rn to trace submarine groundwater discharge in a tidal period along the coast of Xiangshan, Zhejiang, China

²²²Rn is one of the operative tracers for submarine groundwater discharge (SGD), which plays a significant role in the land–ocean interaction of the estuarine and coastal regions. By the distribution pattern of ²²²Rn in atmosphere, groundwater and surface seawater, in a full tidal period (25 h) in March 2012, SGD was estimated along the coast of Xiangshan, Zhejiang, China. ²²²Rn activity in Xiangshan coast was in range of 2.4 × 10⁴–1.7 × 10⁵ Bq/m³ with an average of 9.6 × 10⁴ Bq/m³ for groundwater; 0.2 × 10²–2.8 × 10² Bq/m³ with an average of 1.1 × 10² Bq/m³ for surface seawater. ²²²Rn activities in groundwater were much greater than those in surface water, suggesting that the major source of radon came from coastal groundwater discharge. Rn fluxes of atmospheric emissions, sediment, and of ²²⁶Ra in situ decay can be negligible in this study, but the tidal effects play a crucial role in Rn fluxes. Using a radon inventory equilibrium model, we estimated that the average SGD was 13.2 cm/day and the average terrestrial SGD flux was 1.8 × 10⁸ m³/day. Furthermore, SGD may have a vital impact on the composition and structure of nutrients in seawater, and contribute to eutrophication events occurring in spring season along the coast of the East China Sea.     

Activity concentrations of 226Ra, 228Ra, 222Rn and their health impact in the groundwater of Jordan

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.

     

Indoor 222Rn concentrations and the corresponding lung cancer risk in Celein region, west of Al Khums, Libya

Paramagnetic products stabilized in both 4,4′(5′)-di-(tert-butylcyclohexano)-18-crown-6 (DtBuCH18C6) and its solution in 1-octanol upon low temperature (77 K) X-rays irradiation were studied by ESR spectroscopy. Macrocyclic –O–ĊH–CH₂– radicals and acyclic O = C(H)–ĊH–O– radicals were found as main radiolysis products in neat DtBuCH18C6. Fraction of acyclic radicals resulting from the macrocycle cleavage was about 50%. No radical products resulted from t-Bu and cyclohexyl fragments were observed. It was concluded that the primary events were essentially concerned with ionization of the polyether moiety. Irradiation of frozen DtBuCH18C6 solutions in 1-octanol resulted in formation of radicals both from crown ether and alcohol.     

222Rn determination in drinkable waters of a central eastern Italian area: Comparison between liquid scintillation and gamma-spectrometry

Summary It is well known that the interest in radon concentration indoor as a pollutant emerged during the energy crisis of seventies which led to reduce ventilation in dwellings. Recently the Euratom Recommendation 2001/928 suggested the necessity of performing frequent ²²²Rn checks on tap waters. As a consequence of this Recommendation, Urbino and Perugia Universities carried out a preliminary ²²²Rn determination on tap waters of the Pesaro-Urbino province. Samplings were carried out in twenty-eight sites and radon concentration was determined by liquid scintillation counting and gamma-spectrometry. The results obtained by the two techniques were comparable (the deviation from the mean is lower than 10% for 54.5% of the samples). The resulted ²²²Rn concentration was very low (5 Bq ^. l^-1 for 43% of the samples) and, therefore, radon in waters cannot be considered as a direct radiological risk for the local population.     

Long-term behavior of 137Cs and 3H activities from TEPCO Fukushima NPP1 accident in the coastal region off Fukushima,Japan

Journal of Radioanalytical and Nuclear Chemistry - Decreasing trends of both 137Cs and 3H activity concentrations and an increasing trend of 3H/137Cs activity ratio at Fukushima Dai-ichi Nuclear...     

Advantages of low-background liquid scintillation alpha-spectrometry and pulse shape analysis in measuring222Rn, uranium and226Ra in groundwater samples

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.     

Field alpha-spectroscopy of radon (<Superscript>222</Superscript>Rn) and actinon (<Superscript>219</Superscript>Rn) progeny in soil gas: Locating a radon source

Summary The activities of²¹⁸Po,²¹⁴Po and²¹¹Bi were determined in samples obtained of soil/gas. Sampling work was taken in Jáchymov (Czech Republic) at the outcrop of the Geister-vein,by electrostatic precipitation from filtered soil gas on stainless steel disks.The samples were measured in a field laboratory using a semi-conductor alpha-spectrometer.The activities of²¹⁸Po,²¹⁴Po and²¹¹Bi were calculated.Samples taken from active dump material (near-by radon source) exhibited a high²¹¹Bi/²¹⁴Po ratio, while those of the vein outcrop (a relatively deeper source) had a low ratio.A mathematical model was employed to determine the radon age calculated from the actinon/radon input ratio.This varied in a range of 5.6 to -7.7 seconds.Negative age values are probably caused by the preference for actinon, which rapidly comes into equilibrium with the source of this gas.     

222Rn measurements in drinking water and annual effective dose for the adult population around a coal-based and atomic power plant in Uttar Pradesh,India

Journal of Radioanalytical and Nuclear Chemistry - Dissolved radon (222Rn) in drinking water has been measured using SMART RnDuo, a continuous radon monitor. Water samples have been collected from...     

Analysis and processing of samples for a carbon-14 monitoring program at a radioactive waste storage site

A monitoring program was undertaken to determine the levels of airborne radioactive 14CO2 in an operating waste management area, and it its vicinity. As a part of this program, alkaline microporous pellets, recently developed, were used to sample the 14CO2 in air near waste storage structures and near the waste management area. These pellets were never fully characterized for their ability to capture high levels of 14CO2, and the processing and analysis needed to be improved to provide data on recoveries and consistencies, for an eventual method validation, with independent calibrations and standards. The sample analysis scheme also had to accommodate 14CO2 levels varying from near the natural background (250 Bq kg-1 C), to potentially three to four orders of magnitude above this value, near the wastes. The porous alkaline solid pellets were used for the passive capture of airborne 14CO2 over a period of weeks, to a few months. The pellets were processed to release the captured CO2 (14CO2 and 12CO2) into a NaOH solution, which was subsequently analyzed by liquid scintillation. Processing of the pellets yielded a 14C recovery of 96.0 +/- 4.2% and a lower, but consistent total carbon recovery, i.e., 85.9 +/- 2.7 and 86.9 +/- 2.6%, for procedural blanks and standards, respectively. The detection limits for the pellet sampling and processing was sufficient to reach environmental levels. For the higher levels of 14CO2 and for 'spot' sampling, we also used air samples, pumped into a NaOH solution to trap the 14CO2. These NaOH solutions were counted directly for 14C, also by liquid scintillation. The method limits of this latter technique, although much higher than for pellet samples, also achieved the performance objective for detecting airborne 14CO2. Both sampling and processing techniques, when used together, provided sufficient flexibility to be used for low (environmental) levels and high levels, near the wastes.     

Thermal analysis (TG-DTA) and drift spectroscopy applied to investigate the evolution of humic acids in forest soil at different vegetation stages

Humic acids (HAs) extracted from soils developed under two Norwegian spruce (Picea abies, (L.) Karst) subalpine forests of northern Italy were characterized using chemical, thermal (TG-DTA) and spectroscopic (DRIFT) analyses. The samples were taken from five sites which differed in orientation (northern and southern exposure) and vegetal cover at different old age: grassland, regeneration, immature and mature stands. In general, the thermal patterns of HAs were similar (three exothermic reactions appeared around at 300, 400 and 500°C) in both sites in grasslands and regeneration while a considerable modification appeared in HA from stands of different age at northern and southern exposure site. DRIFT spectroscopy confirmed the differences observed through TG-DTA analysis. In particular the main structural changes were ascribed to modification of carbonyl group and of CH stretching in aliphatic components in each HAs from different sites.