共查询到20条相似文献,搜索用时 31 毫秒
1.
Kil Yong Lee Yoon Yeol Yoon Soo Young Cho Kyung Seok Ko Byung-Woo Yum 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(1):27-30
A simple method for the determination of the air?Cwater partition coefficient (Kair/water) of radon (Rn-222) was studied using a liquid scintillation counter. In the present work, the radon activity of groundwater phase in a closed container was measured and used to calculate the partition coefficient instead of the radon activity of gaseous phase in other works. The partition coefficient was determined for four groundwater samples by using a modified equilibrium partition coefficient in closed system method. The effect of temperature on the partition coefficient was investigated at 0, 10, 20 and 30?°C. Within the temperature range, the partition coefficients were 1.72?C2.03, 2.11?C2.28, 2.78?C3.92 and 4.93?C5.61 at 0, 10, 20, and 30?°C, respectively. It was found that the effect of temperature on the air?Cwater partition coefficient of groundwater radon was agreed well with literature values. 相似文献
2.
The radon concentration has been measured in thermal waters used for medical therapy and drinking purposes in Yalova basin, Turkey. Radon activity measurements in water samples were performed using RAD 7 radon detector equipped with RAD H2O (radon in water) accessory and following a protocol proposed by the manufacturer. The results show that the concentration of 222Rn in thermal waters ranges from 0.21 to 5.82 Bql?1 with an average value of 2.4 Bql?1. In addition to radon concentration, physicochemical parameters of water such as temperature (T), electrical conductivity, pH and redox potential (Eh) were also measured. The annual effective doses from radon in water due to its ingestion and inhalation were also estimated. The annual effective doses range from 0.2 to 0.75 μSvy?1 for ingestion of radon in water and from 2.44 to 9 μSvy?1 for inhalation of radon released from the water. 相似文献
3.
Pattama Pisapak Tripob Bhongsuwan 《Journal of Radioanalytical and Nuclear Chemistry》2017,313(1):123-130
The radon concentrations were determined in well water samples from Namom district, Southern Thailand, by using a RAD7 radon monitoring system. The measured values ranged from 0.1 to 483.0 Bq l?1, while the average ±1σ across all measured samples was 32.0 ± 9.2 Bq l?1. Regarding the health risks from radon in household drinking water, some settlements had radon concentration exceeding 100 Bq l?1, an upper limit set by the European Union Directive EC2013/51/EURATOM. It is of concern that the results indicate health risks, especially to those consumers who directly use well water with high radon concentration. 相似文献
4.
B. A. Almayahi A. A. Tajuddin M. S. Jaafar 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(1):133-140
The calibration factor of 0.029 ± 0.0002 track cm?2 per Bq d m?3 for radon concentration measurements was determined using CR-39 and RAD7 detectors. The 222Rn concentration varied from 2,225 to 9,950 and 12 to 1,002 Bq m?3 in soil and water, respectively. The highest radon exhalation and gamma dose rates were found in Acid and undifferentiated granitic rocks and Miscellaneous soils. 相似文献
5.
Bo-chao Xu W. C. Burnett Derek Lane-Smith Zhi-gang Yu 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):457-463
Measurements of 222Rn (“radon”) in the environment are important in the geosciences and radiation-protection fields. We demonstrate here a simple
laboratory-based calibration system to evaluate the efficiency of radon detectors with a reproducibility of about ±2%. The
system uses a closed-loop air circulation design with 226Ra adsorbed onto MnO2-impregnated fiber as a radon source. Two RAD7 radon detectors (Durridge Co., Inc.) that were precisely calibrated at Durridge’s
in-house calibration facility are used as secondary standards. By parallel analysis of the radon-enriched air within the closed
loop, the test RAD7s are assigned a calibration coefficient to be applied to future measurements. We also performed a side-by-side
intercomparison with two RAD7s in a high-radon natural environmental setting (limestone cave in Florida) that produced comparable
results. 相似文献
6.
《International journal of environmental analytical chemistry》2012,92(1):32-41
ABSTRACTThe purpose of this study is to estimate the concentrations of radon and heavy metals in drinking water and assess their health implications to the population of Quetta, Pakistan. The concentration of radon and heavy metals was measured in drinking water collected from tube wells of different depths of the Quetta, Balochistan, Pakistan, using RAD7 detector and Atomic Absorption Spectrometer, respectively. The results show that the concentration of radon ranged from 3.56 ± 0.98 to 8.56 ± 1.32Bq/L with an average of 5.67 ± 1.34Bq/L. The average value of contribution of radon in water to indoor air was found 2.02 ± 0.47mBq/L. In addition to concentration of radon in drinking water, physiochemical parameters like pH and electrical conductivity (EC), and annual effective doses for different age groups were also estimated. Positive correlation of (R2 = 0.8471) was observed between depth of well and concentration of radon, however no such relations were found among pH and EC with concentration of radon. Average values of annual effective doses due to intake of radon for age groups 0–1 years (infants), 2–16 years (Children) and ≥17 years (adults) were found (3.00 ± 0.71)×10?2, (1.1 ± 0.26)×10?2 and (1.45 ± 0.34)×10?2 mSv/y, respectively. Average values of heavy metals concentrations were found 1.85 ± 0.64, 3.21 ± 0.75, 5.06 ± 1.19, and 2.47 ± 0.77 and 5.58 ± 1.23 µg/L for As, Cr, Ni, Cd and Pb, respectively. The values of radon concentration and heavy metals in drinking water were found below the USEPA permissible limits, Thus we conclude that, the investigated waters are safe. 相似文献
7.
S. Selvasekarapandian R. Sivakumar N. M. Manikandan V.M. Ragjunath V. Kannan S. Rajaram 《Journal of Radioanalytical and Nuclear Chemistry》2002,252(2):345-347
The gas collection measurement method was employed to determine radon activity concentrations in the water of Coonoor. Open well water, dam water and stream water have been investigated for their radon concentrations. It is observed that the highest radon concentration is in the open well water and the lowest in stream water. From these measurements, the corresponding annual effective ingestion dose is determined. 相似文献
8.
Kazumasa Inoue Masahiro Hosoda Shinji Tokonami Tetsuo Ishikawa Masahiro Fukushi 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(3):2009-2015
The temporal variation of the radon concentration, and the radon and thoron concentrations every 3 months for a year were measured using two types of devices in a landmark skyscraper, the Tokyo Metropolitan Government Daiichi Building. In the measurement of temporal variation of the radon concentration using a pulse type ionization chamber, the average radon concentration was 21 ± 13 Bq m?3 (2–68 Bq m?3). The measured indoor radon concentration had a strong relationship with the operation of the mechanical ventilation system and the activities of the office workers. The radon concentration also increased together with temperature. Other environmental parameters, such as air pressure and relative humidity, were not related to the radon concentration. In the long-term measurements using a passive radon and thoron discriminative monitor, no seasonal variation was observed. The annual average concentrations of radon and thoron were 16 ± 8 and 16 ± 7 Bq m?3, respectively. There was also no relationship between the two concentrations. The annual average effective dose for office workers in this skyscraper was estimated to be 0.08 mSv y?1 for 2000 working hours per year. When considering the indoor radon exposure received from their residential dwellings using the annual mean radon concentration indoors in Japan (15.5 Bq m?3), the annual average effective dose was estimated to be 0.37 mSv y?1. This value was 31 % of the worldwide average annual effective dose. 相似文献
9.
M. Mirhabibi A. Negarestani M. A. Bolorizadeh M. R. Rezaei A. Akhound 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(1):207-211
Temporal variations of radon concentration in soil before the earthquake are known as an earthquake precursor. For using of radon as an earthquake precursor, it is necessary to constantly monitor radon concentration variations in a relatively wide range in the vicinity of a fault which is virtually impossible for radon detectors that already exist. This paper proposes a new method for continuous measurement of radon concentration variations in a wide range, using optical fiber as radon detector. For this purpose, an experimental system consisting of radon source, optical-fiber holding chamber, radon gas detector, optical laser source, and optical power meter have been arranged to with the aim to create different concentrations of radon gas in the vicinity of the optical fiber; the attenuation which creates on optical fiber is subsequently measured. As a result, the average of the attenuation is 0.004 μw per each meter per Bq/l since the fault’s length is more than ten kilometers; sensitivity of the measurement can be improved many times over. 相似文献
10.
Nabil M. Hassan 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):111-117
Wasted petroleum, scale and sludge, samples associated with petroleum industries have elevated level of radionuclides concentrations which increase the radiation dose received to the workers. Radon concentration, emanation coefficient and exhalation rate give good information about the radioactivity levels. Twelve samples of scale, sludge and sand, collected from different oil fields in the Red Sea Refineries company for petroleum services in the eastern desert of Egypt, were selected for this study. Radon concentration released from selected samples was measured using AlphaGUARD radon monitor. Radon emanation coefficient and its exhalation rate were calculated based on the measured value of radon concentration. Correlation among radon exhalation rate with radium content and “emanated radon concentration” (radium concentration × emanation coefficient) as well were found to be of 0.94 and 0.99, respectively. Therefore, radon exhalation rate could be useful index for both radium concentration and emanated radon. Radon emanation coefficient was increased more than twice due to water content within material of less than of 10 %. 相似文献
11.
Matiullah 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):369-373
CR-39 based radon detectors are widely used in measuring indoor radon. In this regard, different groups have developed their own systems. However, before using any system for indoor radon measurements, it has, first, to be calibrated with a known source of radon. In the current study, CR-39 based NRPB type radon detector has been calibrated and presented. In this regard, about 200 holders for CR-39 were obtained from the Radiation Protection Division of the Health Protection Agency (former NRPB), UK and several thousand more similar detector holders, hereafter called NRPB type holders, were fabricated locally in Pakistan. Uranium ore samples of known grade were placed into the plastic containers of volume 5.4 × 103 cm3 and CR-39 detectors were placed in the NRPB type holders and were then installed into the containers at a distance of 25 cm from the surface of the known grade ore samples. The containers were hermetically sealed and the detectors were allowed to expose to radon for 3 weeks. After 16 h etching in 25 % NaOH at 80 °C, the measured track densities were related to the radon concentration. The calibration factor of 2.563 tracks cm?2 h?1/kBq m?3 was obtained. 相似文献
12.
Y. Kobayashi S. Tokonami Y. Narazaki W. Zhuo M. Furukawa 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(3):389-396
Summary Radon measurements were carried out in a Japanese wooden house built on granitic geology, where radon-rich well water is used.
Atmospheric radon concentrations were measured over one year with passive integrated radon monitors. The monitors were distributed
at several locations in the house and were replaced every two months. In order to confirm the diurnal variation and heterogeneous
distribution of radon, short-term measurements were carried out accordingly. Radon, its decay products and terrestrial gamma-radiations
were measured in this survey. From the long-term measurement, the radon concentration in the house ranged from 14 to 184 Bq. m-3with an arithmetic mean of 45 Bq. m-3. A radon concentration of 184 Bq. m-3was observed in the bathroom in spring (March-May) though the radon level was normal in the living room and bedroom. In order
to characterize the house, similar measurements were conducted in several surrounding houses. There was a significant difference
in radon concentration between the investigated houses. There was a spatial distribution of the radon concentration and the
highest value was found in the bathroom. Radon and its decay products concentrations varied with time, which increased from
midnight to morning whereas they decreased during daytime. Although the radon concentration in tap water was 1 Bq. l-1, a high level of 353 Bq. l-1was found in the well water.While well water was being used, the indoor radon concentration near the bathroom increased rapidly
with a maximum value of 964 Bq. m-3. It is clear that the use of well water enhanced the radon level around the bathroom. 相似文献
13.
M. Zoran R. Savastru D. Savastru 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(3):877-888
Atmospheric radon concentration was continuously monitored in Bucharest-Magurele area both near the ground at 1 m height as well as at 10 m height. This paper presents the results of radon in air near the ground concentrations obtained during the 1 July 2010 to 1 February 2012 period by use of solid state nuclear track detectors SSNTD CR-39. The mean atmospheric radon concentration near the ground at 1 m height was found to be 360.91 ± 66.49 Bq/m3, which was about more than an order of magnitude lower than average radon concentration in range of 44.92 ± 9.94 Bq/m3 recorded for period 1 August 2011 to 20 December 2011 at 10 m height by AlphaGUARD Radon monitor. The meteorological effects on the variation of atmospheric radon concentration were discussed. The analysis of spatio-temporal variations in time series radon concentration in air near the ground is a useful tool to study geo-dynamical processes associated with seismic activity in active Vrancea zone in Romania. Taking off the variations induced by external variables, such as temperature, barometric pressure, rainfall, and other meteorological parameters, can be assessed radon anomalies due to possible tectonic movements and also can be surveyed radioactivity background in relation with nuclear emergencies. 相似文献
14.
Mansoureh Mansour Bahmani Alireza Heravi Moussavi Alireza Vakili Mohammad Reza Rezaie Hassan Reza Dehghan Elham Rezvan Nejad 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(3):653-657
Milk is considered as the richest nutrition, being used by people. When drinking milk or water the radon gas will transfer from air to them rapidly. Since milk is majorly composed of water, probably radon existence in livestock consumable water could be the main cause of its presence in milk. Different portion of milk changed by radon gamma ray and consumption of radon included water or milk has its effects on the human body. For investigation the effect of radon in water or milk on human organs, this study has been done in two phases with MCNPX software. In the first phase, the dose rate of absorbed gamma ray by different portion of milk which is indoctrinated by 1 Bq/m3 of radon during a day is calculated. Moreover, the effects shown by milk and its components in radon gamma spectrum, which is demonstrator of milk absorption spectrum, are also surveyed. In the second phase as well, according to the human body phantom, the absorbed gamma dose caused by daily consumption of indoctrinated water or milk with 1 Bq/m3 radon is calculated. The production rate of free radicals in milk and its different components are derived according to escape data of MCNPX code. 相似文献
15.
G. Prasad T. Ishikawa M. Hosoda A. Sorimachi S. K. Sahoo N. Kavasi S. Tokonami M. Sugino S. Uchida 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1385-1390
Radon and thoron concentration in the outdoor environment are affected by the magnitude of the exhalation rate that can vary
diurnally and seasonally. This paper presents measurement results of radon and thoron exhalation rates and gamma-ray dose
rate in different season at same location points in Gunma Prefecture Japan. Exhalation rates were measured by the MSZ instrument
which is based on the accumulation method. Three measurement points Katashina Village, Midori City and Takasaki City were
selected for measurement. Soil water saturation and soil temperature were measured to investigate their relationship with
exhalation rate. The diurnal variation of exhalation rate may be correlated with soil temperature but no clear relationship
was found between them. The gamma-ray dose rate do not vary significantly at the same places even in different season. The
average radon exhalation rates were 11 ± 2, 2 ± 1, 5 ± 3 and 11 ± 4 mBq m−2 s−1 for spring, summer, autumn and winter, respectively. Those for thoron were 1,100 ± 100, 120 ± 30, 250 ± 80 and 860 ± 140 mBq m−2 s−1. Thus there was a variation of radon and thoron exhalation rate with different seasons. The radon and thoron exhalation rates
in the summer and autumn surveys are higher than those in the spring and winter surveys which were affected by rainfall. It
indicates that water saturation is an influential factor for radon and thoron exhalation rates. 相似文献
16.
T. Turtiainen 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):325-331
Slab-on-ground is a typical base floor construction type in Finland. The drainage layer between the slab and soil is a layer
of sand, gravel or crushed stone. This layer has a minimum thickness of 200 mm and is sometimes even 600 mm thick, and thus
may be a significant contributor to indoor air radon. In order to investigate radon emanation from the drainage layer material,
a simple laboratory test was developed. Many organic solvents have high Ostwald coefficients for radon, i.e., the ratio of
the volume of gas absorbed to the volume of the absorbing liquid, which enables direct absorption of radon into a liquid scintillation
cocktail. Here, we first present equations relating to the processes of gas transfer in emanation measurement by direct absorption
into liquid scintillation cocktails. In order to optimize the method for emanation measurement, four liquid scintillation
cocktails were assessed for their ability to absorb radon from air. A simple apparatus consisting of a closed glass container
holding an open liquid scintillation vial was designed and the diffusion/absorption rate and Ostwald coefficient were determined
for a selected cocktail. Finally, a simple test was developed based on this work. 相似文献
17.
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
18.
Bayram Can Cumhur Canbazoğlu Nesli Albayrak Nilgün Çelebi Mahmut Doğru 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1059-1063
The fact that 50% of the natural radiation dose to which humans are exposed is caused by radon gas makes indoor radon measurements important. In this study, levels of indoor radon gas were measured in 204 houses in Kilis, Osmaniye and Antakya using passive nuclear track detectors. Cr-39 radon detectors were left in the living rooms of participants’ houses, then analyzed at the Radon Laboratory of Health Physics Department in Çekmece Nuclear Research and Training Center (ÇANEM) of Atomic Energy Agency of Turkey (TAEK). Average indoor radon activity concentrations for Kilis, Osmaniye and Antakya were 50 Bq/m3 (1.26 mSv/y), 51 Bq/m3 (1.29 mSv/y) and 40 Bq/m3 (1.01 mSv/y), respectively. 相似文献
19.
Kil Yong Lee Yoon Yeol Yoon Kyung Seok Ko 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(2):381-385
The radon emanation coefficient (ε) from aquifer rock and the Henry’s law constant (H) of radon were determined by measuring activity concentrations using liquid scintillation counter (LSC). For the evaluation of the method, the coefficients were measured at 0, 10 and 20 °C and the temperature dependency of the coefficients was compared with others. The radon emanation coefficients from the rock particles used in this work are 0.0845, 0.1007 and 0.1308 at 0, 10 and 20 °C, respectively. The dimensionless Henry’s law constants for the groundwater used in this work are 0.994, 1.153 and 2.641 at 0, 10 and 20 °C, respectively. The results show a good agreement with those in literatures. 相似文献
20.
Tabassum Nasir Matiullah Muhammad Rafique Saeed Ur Rahman Muhammad Khalil Naveed Anwar 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(3):1209-1215
In order to carry out indoor radon measurement in new and old buildings of the Dera Ismail Khan city, CR-39 based radon detectors were installed in bed rooms and sitting rooms/TV lounges in 25 (each) old and new houses and were exposed to indoor radon for 90 days. After processing, mean weighted average indoor radon concentrations in old and new houses were found to be 275 ± 33 and 86 ± 18 Bq m?3 whereas mean annual effective doses expected to be received by the occupants were 6.86 ± 0.79 and 2.1 ± 0.43 mSv year?1, respectively. From the measured weighted average indoor radon concentration, excess relative risk factor was calculated using the risk model of BEIR VI for the age group of 35 and 55 years. Average excess lung cancer risk was found to be 1.63 ± 0.19 and 1.35 ± 0.16 and 0.5 ± 0.10 and 0.4 ± 0.08 for old and new houses, respectively. 相似文献