Authors:Bo-chao Xu, W. Burnett, Derek Lane-Smith, and Zhi-gang Yu
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
Authors:Marian Calin, Maria Zoran, and Mihaela Calin
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.
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.
Authors:T. Ishikawa, M. Hosoda, A. Sorimachi, S. Tokonami, S. Katoh, and S. Ogashiwa
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.
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.
Authors:K. Babai, S. Poongothai, K. Lakshmi, J. Punniyakotti, and V. Meenakshisundaram
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.
Authors:K. Reddy, M. Reddy, Ch. Reddy, P. Reddy, and K. Reddy
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.
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.
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.
Authors:Iveta Smetanová, Karol Holý, Monika Müllerová, and Anna Polášková
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.