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Abstract  

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.

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Abstract  

Due to their low radioactivity background, underground salt mines spaces offer a unique possibility for speleotherapy use. The knowledge of radon concentration levels in such underground environments is essential for therapeutic purposes of different respiratory and rheumatic diseases. In order to develop speleotherapy in Romania, this paper presents the results of an indoor radon concentration levels survey in some salt mines in Romania. The survey was carried out using radon monitor Pylon AB-5 system methodology validated by a CIS-P5M system. In order to investigate whether differences in depth and microclimate parameters translate into significant differences in salt mine indoor radon concentrations, have been chosen three salts mine test sites placed in the Northern part of Romania (Turda, Cacica and Ocna Dej) in stable areas of the mining field at 32–120 m depth. Environmental microclimate conditions (mean values of air temperature 10–14.5 °C, air humidity 65–80%, air velocity 0.2 m/s saline aerosols and low microbial factors) have anti-bacterial, anti-microbial, and anti-inflammatory properties and recognized therapeutically effects on human body’s health. Air temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations in salt mines because temperature largely determines close spaces ventilation rates, and ventilation habits are known to have significant effects on indoor radon concentrations. The analyzed environmental conditions and recorded low levels of indoor mean radon concentration (6.9 ± 0.39 and 96.5 ± 4.76 Bq/m3) demonstrated the best suitability of the investigated three salt mines in Romania for speleotherapeutic applications.

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Abstract  

Measurement of radon is of interest both for the health risk assessment and development of radon therapy in enclosed spaces like as caves, mines and spas. In Romania, radon therapy is not in use, yet. The development of this treatment method in mines from our country involves primarily, the evaluation of radon levels in the salt mines. In this paper, the results of radon gas measurement that were performed at Ocna Dej salt mine (Romania) are presented. The radon measurements were performed using two systems: radon monitor Pylon AB-5 system and CIS-P5M system. The average radon concentration was found to be between 9.14 ± 5.10 Bq/m3 and 31.70 ± 2.76 Bq/m3. These radon levels are lower in comparison to those reported for mines, caves or spas in other countries where radon therapy and speleotherapy is frequently in use. Radon concentration and environmental conditions from Ocna Dej salt mine are suitable for therapeutic applications.

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Abstract  

Nowadays, artificial “radon spa sources” for home baths are commercially available. Although these sources could give a potential radiation exposure to the users, few studies have been reported on their radiological measurements. In the present study, five types of radon spa sources were collected and their radiological characterization was investigated. The followings were estimated for these samples: (1) radon emanation coefficients (dry and water-saturated conditions), (2) surface γ-ray dose rate, (3) surface count rates for α- and β-rays, (4) activity concentrations of 226Ra, 232Th and 40K, and (5) concentrations of radon and thoron generated from the sources located in an air flow system. The activity concentrations were very high (except for one sample (named “sample B”), although radon emanation coefficient was low compared with soil. This leads to high concentrations of radon/thoron generated from the sample. The maximum surface γ-ray dose rate was observed for sample A (2.7 μGy h−1). If people stay very close to the sample for a long time, the exposure might be significant.

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Abstract  

This study was conducted primarily to measure and map radon activity concentration in wells within water supply network of Khartoum State. Ground water samples were collected before and after autumn and analysed using low level γ-spectrometry equipped with HPGe-detector. Radon activity concentration was found in the range of 1.58–345.10 Bq/L with an average value of 59.20 ± 6.60 Bq/L. Upon comparing the radon concentration values obtained with EPA it was found they were far below the maximum contaminant level of EPA with the exception five samples. Physicochemical water parameters were measured and no correlation was noted between radon concentration and these parameters. The overall annual effective dose for adults due to radon ingestion is less than WHO recommended reference dose level for most except 14 samples.

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Abstract  

Indoor radon concentrations were measured inside different types of dwellings in Chennai city on a quarterly basis using a solid state nuclear track detector (LR-115, Type II) for 1 year. Significant seasonal variations were observed. The average highest radon concentration was observed during winter (86.08 Bq m−3) and the lowest in summer (42.50 Bq m−3). The radon concentrations were also varying on the basis of different floor-covering materials. For a given season, the average maximum radon concentration was observed with cement flooring (118.96 Bq m−3) followed by tiles (75.25 Bq m−3) and marbles (74.04 Bq m−3). Also, outdoor soil samples were collected in and around the same dwellings and determined the radioactivity content of three primordial radionuclides (238U, 232Th and 40K) in these soil samples using NaI(Tl) scintillation detector based gamma-ray spectrometer.

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Abstract  

Radon and thoron have been identified as potential radiological health hazard and the dose estimation due to their exposure is an important task. Understanding their behavior in indoor environment helps in calculating the inhalation doses due to them. Present study aims at the distribution of radon and thoron concentrations in a typical Indian dwelling. Solid state nuclear track detectors are employed in the study. The concentration of radon is found to be invariant in indoor environment. The thoron concentration is found to decrease exponentially as a function of distance from the source (wall/floor). Solution of one dimensional diffusion equation is used for regression fittings for thoron variation, from which the diffusion constants and the exhalation rates were calculated. The diffusion constants varied from 0.00195 to 0.00540 m2 s−1.

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Abstract  

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.

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Abstract  

An important parameter for evaluating the possibilities of use of enclosed spaces (mines, caves, spas, etc.) for therapeutic purposes is the concentration of radon in different conditions of ventilation. The aim of this paper is to present the results of continuous radon gas measurement that were performed for ten days, at 20 min time intervals in different locations from Cacica salt mine (Romania) using a portable radon monitor. The average radon concentration was found to be between 96.5 ± 4.76 Bq/m3 and 20.5 ± 1.30 Bq/m3. These values are suitable for therapeutic applications and are useful for future experiments regarding the development of the radon therapy and speleotherapy in this salt mine.

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Abstract  

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.

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