共查询到20条相似文献,搜索用时 515 毫秒
1.
H. Dulaiova R. Peterson W. C. Burnett D. Lane-Smith 《Journal of Radioanalytical and Nuclear Chemistry》2005,263(2):361-363
Summary Radon-222 is a good natural tracer of groundwater discharge and other physical processes in the coastal ocean. Unfortunately, its usefulness is limited by the time consuming nature of collecting individual samples and traditional analysis schemes. We demonstrate here an automated multi-detector system that can be used in a continuous survey basis to assess radon activities in coastal ocean waters. The system analyses 222Rn from a constant stream of water delivered by a submersible pump to an air-water exchanger where radon in the water phase equilibrates with radon in a closed air loop. The air stream is fed to 3 commercial radon-in-air monitors connected in parallel to determine the activity of 222Rn. By running the detectors out of phase, we are able to obtain as many as 6 readings per hour with a precision of approximately ±5-15% for typical coastal seawater concentrations. 相似文献
2.
We have measured the variation of atmospheric pressure and of 222Rn activity concentration in the air of a wine cellar with an AlphaGAURD type ionization chamber radon monitor. We have found
that the 222Rn activity concentration varies inversely with pressure. To explain this behavior we have done model calculations. We have
compared the results of model calculations with the results of experimental measurements, and we have found that the model
is capable to reproduce some part of the variation of 222Rn activity concentration. 相似文献
3.
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
4.
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
5.
W. C. Burnett G. Kim D. Lane-Smith 《Journal of Radioanalytical and Nuclear Chemistry》2001,249(1):167-172
Radon-222 is a good natural tracer of groundwater flow into the coastalocean. Unfortunately, its usefulness is limited by the time consuming natureof collecting individual samples and traditional analysis schemes. We demonstratehere an automated system which can determine, on a continuousbasis, the radon activity in coastal ocean waters. The system analyses 222Rn from a constant stream of water passing through an air-water exchangerthat distributes radon from the running flow of water to a closed air loop.The air stream is feed to a commercial radon-in-air monitor which determinesthe concentration of 222Rn by collection and measurement of theemitting daughters, 214Po and 218Po, via a charged semiconductordetector. Since the distribution of radon at equilibrium between the air andwater phases is governed by a well-known temperature dependence, the radonconcentration in the water is easily calculated. 相似文献
6.
We have investigated the possibility of determining the relative concentrations of two radon isotopes (222Rn and220Rn) in the air, using solid state nuclear track detectors (CR-39) as alpha spectrometers. The detectors were exposed to222Rn and its daughters and220Rn and its daughters in the air. Analyzing only roundish tracks, it was observed that the performance of CR-39 as alpha spectrometer varies with etching time, improving markedly for long etching times. 相似文献
7.
Iveta Smetanová Karol Holý Monika Müllerová Anna Polášková 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(1):101-109
Seasonal and short term variations of 222Rn activity concentration in borehole air and water of the borehole drilled in cracked quartzite were studied and possible
response on meteorological parameters was examined. Seasonal change of radon concentration in borehole air due to atmospheric
temperature was confirmed. Short term variation of radon concentration in borehole air coincided with the atmospheric pressure
changes. The strong impact of rainfall on radon concentration values was observed both in air and water environments. The
decrease of radon content in borehole air and water followed radioactive decay law exclusively in spring and summer month.
Contrary to borehole water, rainfall increased radon concentration in borehole air during spring and summer months only. In
this paper the results from two and half years of investigation are presented. 相似文献
8.
J. J. Labrecque 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(3):439-444
The determination of soil-gas anomalies especially 222Rn anomalies, are important to precisely locate fault traces, as well as to investigate earthquake precursors. In this paper, we have studied and compared new rapid methods for on site determinations of radon (222Rn), thoron (220Rn) and total radon (222Rn+220Rn) in soil-gas. These new techniques pump the soil-gas continuously from the soil through a simple sampling tube to the counting cell for one-minute with discarding the excess. Then, either four one-minute counting periods (5-minute technique) or nine one-minute counting intervals (10-minute technique) are followed immediately. In all the methods, conversely to Morse"s method, the first counting period (C1) was not employed for calculations. Three calculation methods for the five-minute technique, two for the ten-minute technique and a modified Morse"s method are compared with theoretical values and different real soil-gases with different radon/thoron ratios. The affect of different flow rates of soil-gases into the counting cell was also investigated. Finally, the ten-minute technique seems to be a little more accurate, but the 5-minute technique is much more suitable for seismic field studies when a much larger number of determinations are required in a short time. 相似文献
9.
A new determination method for222Rn and220Rn in water sample was developed by extracting radon with toluene and applying the integral counting method with a liquid
scintillation counter. The essential characteristics of the methods are, (1) extraction of radon with toluene from water,
(2) finding absolute counts and making corrections for the quenching effect by the adoption of the integral counting method,
(3) the determination of222Rn and220Rn was performed by counting the activity of220Rn with its descendants and of ThB (212Pb) with its descendants in a radioactive equilibrium, respectively, (4) realizing high sensitivity by simultaneous counting
of α, β− particles emitted from the decay products formed in toluene. The lowest detection limit obtained by the present method was
5.0·10−13 Ci/l for222Rn and 6.8·10−8 Ci/l for220Rn in water. 相似文献
10.
Michael E. Kitto Christopher D. Judd Miguel A. Torres Clayton J. Bradt 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):57-62
A study to characterize the radionuclide and chemical components in a radium-ore revigator has been completed. Measured activities of dissolved 222Rn, 226Ra, and U isotopes, determined in the water using radioanalytical techniques, exceeded recommended limits in drinking-water supplies. Trace-metal concentrations, determined using inductively coupled plasma mass spectrometry, increased in the water with exposure time and exceeded recommended drinking-water limits for V and As. The contribution to, and dose from, the airborne radon-gas level in a room due to radon emanation from a revigator were evaluated. The annual committed effective dose resulting from consuming the radionuclides in the revigator water were estimated to be ~100 μSv/y for combined uranium and radium. 相似文献
11.
D. R. Corbett W. C. Burnett P. H. Cable S. B. Clark 《Journal of Radioanalytical and Nuclear Chemistry》1998,236(1-2):247-253
Determination of sedimentary fluxes of222Rn via diffusion was required as an input for a mass balance model of radon in a freshwater lake. We obtained these fluxes
by: (1) direct measurement in the laboratory using a simulated sediment bed and water column; (2) a “sediment equilibration”
technique; and (3) porewater modeling. The first method, analogous to an in situ benthic chamber approach, uses direct observation
of the increasing222Rn activity in water overlying a sediment bed packed in plastic columns. This allows one to directly measure the fluxes and
determine the effective wet bulk sediment diffusion coefficient (D
s). Radon flux estimates using these three techniques agreed to within approximately 10–15%. 相似文献
12.
E. M. Köksal N. Çelebi B. Ataksor A. Ulug M. Taşdelen G. Kopuz B. Akar M. T. Karabulut 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(2):213-216
As part of a national program to determine public exposure to natural radiation, indoor air 222Rn concentrations were determined in dwellings of Turkey. The 222Rn concentrations were measured with time-integrating passive nuclear etched track detectors in 27 provincial centers. The
indoor radon concentrations were found to be in the range of 10-380 Bq.m-3.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
D. Desideri C. Roselli C. Testa A. Bassignani P. Finazzi 《Journal of Radioanalytical and Nuclear Chemistry》1990,142(2):445-451
Research was carried out to evaluate the possible correlation between the uranium content in host rocks and the Rn and daughters concentration in air for two Italian ZnS-PbS mines. As a great variability had been ascertained for222Rn and daughters concentration in the different areas, it appeared of some interest to verify whether this fact was due to a different uranium concentration in the host dolomitic rocks or simply to a ventilation problem. Some rock samples were collected in several places where also radon and daughters were drawn; uranium was determined by fluorimetry and by alpha spectrometry after a chemical separation with a Microthene-TOPO column.222Rn was measured by the scintillation cell method, while the decay products were determined by the Markov and Tsivoglou methods. No correlation could be found between uranium content and radon concentration, but a good linearity was detected between the uranium content and the concentration of Rn decay products (alpha potential energy). 相似文献
14.
Alpha- and beta-activities per unit volume of air due to radon (222Rn), thoron (220Rn) and their progenies were measured in the air of natural caves and ancient mines as well as inside different reference
atmospheres by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). In addition, the radon concentration
was continuously measured inside one of the studied caves by using the SSNTDs’ method and AlphaGuard counter. Equilibrium
factors between radon and its daughters and between thoron and its progeny were evaluated in the studied atmospheres. Alpha-activities
due to 218Po and 214Po short-lived radon decay products were determined in different compartments of the respiratory tract of members of the public.
The committed equivalent doses due to the 218Po and 214Po radon short-lived progeny were evaluated in different tissues of the respiratory tract of the visitors of the considered
caves and ancient mines. Annual effective doses due to radon progeny from the inhalation of air by the visitors of the studied
caves and ancient mines were evaluated. 相似文献
15.
Maria Zoran Mariana Rodica Dida Roxana Savastru Dan Savastru Adrian Dida Ovidiu Ionescu 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(2):729-746
The aim of this paper is to contribute with new information in the application of ground based radon (222Rn) observations to atmospheric research, namely its relation with air pollution due to ground-level ozone (O3) and particle matter in two size fractions (PM10 and PM2.5) for Bucharest metropolitan area in Romania. During January 1–December 31, 2011, ground levels of radon, ozone and particulate matter (PM) have been continuously monitored in synergy with the main meteorological parameters (air temperature, humidity and pressure), and daily global air quality indices. A systematic analysis of surface ozone observations of ground level radon, ozone and PM is presented. Observational results indicate the following yearly daily mean ground level concentrations: 40.26 ± 7.54 Bq/m3 for radon, 90.51 μg/m3 for ozone, 35.96 μg/m3 for PM2.5, and 40.91 μg/m3 for PM10. The assessment of the results showed the influence of local and meteorological conditions on the daily mean radon, ozone and PM concentrations. However, in densely populated metropolitan area of Bucharest the mean daily values of ozone, PM2.5, PM10, and attached 222Rn are sometimes higher than European Community limit values leading to serious public concern during the last years. Due to the high risk of increased levels of O3, PM2.5, PM10, and attached 222Rn on human health respiratory function (especially for children and older persons), and urban green, the results are very useful for atmospheric, radiological protection, epidemiological and environmental studies. 相似文献
16.
N. E. Whitehead R. G. Ditchburn 《Journal of Radioanalytical and Nuclear Chemistry》1995,198(2):399-408
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. 相似文献
17.
B. K. Sahoo T. K. Agarwal J. J. Gaware B. K. Sapra 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1417-1420
This paper presents the extent of thoron (220Rn) interference in the radon (222Rn) exhalation rate, measured by solid state nuclear track detector based ‘Can’ technique. Experiments were carried out following the standard procedure of ‘Can’ technique as well as active technique as a reference method for 222Rn and 220Rn exhalation measurements. It was found that 220Rn interference may lead to overestimation of 222Rn exhalation by a significant factor which can be as high as 12 depending upon the rate of 220Rn exhalation from samples. 相似文献
18.
R. Prakash K. Srinivasamoorthy S. Gopinath K. Saravanan F. Vinnarasi G. Ponnumani S. Chidambaram P. Anandhan 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(1):25-36
Submarine groundwater discharge is the fresh groundwater discharge to sea that impacts the coastal regions. Radon (222Rn) isotope has been used to quantify SGD in coleroon river estuary, India. Continuous 222Rn analyses were attempted for 10 days in groundwater and pore water samples at three different locations. 222Rn in groundwater ranges between 35.0 and 222.0 Bq m?3 and in pore water between 14.0 and 150.0 Bq m?3 irrespective of locations. The radon mass balance estimated total SGD rate ranges between 2.37 and 7.47 m days?1. The SGD increases with distance from coast, influenced by tides and hydrological features. 相似文献
19.
M. A. Misdaq H. Ezzahery J. Lamine 《Journal of Radioanalytical and Nuclear Chemistry》2002,252(1):67-74
A new Monte Carlo computer code was developed for determining the detection efficiencies of the CR-39 and LR-115 II solid state nuclear track detectors (SSNTD) for a-particles emitted by radon (222Rn) and thoron (220Rn) series inside the atmosphere of dwelling rooms. Alpha-activities due to radon, thoron and their decay products, were evaluated for the determination of the detection efficiencies of the SSNTD utilized for the emitted a-particles by measuring the corresponding track densities. The influence of the ventilation rate and building material on the concentration of radon, thoron and their progenies was investigated. Equilibrium factors between radon and its progeny and between thoron and its daughters have been evaluated in the air of the rooms. 相似文献
20.
Permanent probes to sample soil gases were placed at the Latera geothermal field, located in the Volsini Mts., Latium, Italy. Due to high uranium concentrations in the area's alkali-potassic volcanics outcropping, quite high222Rn values, ranging from 9,260 up to 753,000 Bq/m3, were found. The highest radon activities match tectonic structures such as fractures and faults, and a deep high structure which constitutes the geothermal reservoir. These high radon values also conform to a major amount of4He and CO2. The latter gases are enriched in the gaseous phase of the geothermal fluids, and their migration is also controlled by structural features. This suggests that the enrichment of222Rn in the soil gases, can be linked to a direct contribution of226Ra, carried by deep-seated fluids from the reservoir itself. 相似文献