Indoor radon evaluations in specific regions of the country have been performed in an effort to assess the magnitude of the
radon problem and its public health consequences. The survey of this paper covers four large non-tropical regions of north
and central Mexico, and reports the results of measurements of indoor radon concentrations in houses of towns with between
100,001 and 500,000 inhabitants. The measurements were done by using passive detectors, namely, the closed-end-cup system
with CR-39 polycarbonate chips as detector material. The measurements were performed throughout the two coldest seasons (between
5 and 20°C), winter and spring, in integration periods of 28 days covering the six month cycle. The results show a moderate
average radon concentration below 200 Bq·m−3 with occasional higher values. This is very probably due to the climate conditions and the traditional habits of open door
and window ventilation. The IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México) Laboratory, where the closed-end
cup system for radon was developed, has gained experience though this survey and is willing to share it for future surveys
at regional or national levels.
Authors:J. Somlai, J. Hakl, N. Kávási, G. Szeiler, P. Szabó, and T. Kovács
Radon can accumulate in underground areas such as show caves. Repairmen and tourist guides working in such caves may thus
be exposed to significant radiation doses. Therefore, it is necessary to measure the radon concentration to estimate the exact
radiation dose caused by radon. Considering that the radon concentration in caves usually shows significant seasonal fluctuations,
the monthly change of radon concentration was studied for 1 year in nine show caves opened to the public in Hungary. Despite
the fact that all of the caves were formed in karst rocks, the annual average radon concentration levels were rather different
between each other (541–8287 Bq m−3). The significant monthly fluctuation of the radon concentration indicates that the annual average radon concentration in
caves can only be accurately obtained by year-long measurements.
Indoor radon concentrations in the kidergartens of Osijek, Croatia, have been measured with -scintillation cells, LR-115 nuclear track detectors, as well as a Radhome semiconductor detector. Average values of 50.2, 43.7 and 47 Bq m–3 were obtained, respectively. Under the worst conditions, the annual radon effective dose equivalent was 10 mSv y–1. Using bare and filtered LR-115 detectors, the average equilibrium factor was assessed as 0.36 indoors. Measurements of the -dose rate in the kindergartens did not show any significant correlation with the radon concentration. Indoor radon concentrations in the kindergartens of Ljubljana, Slovenia, measured by scintillation cells had an arithmetic mean and standard deviation of 228 and 143 Bq m–3, respectively.
Authors:Tasoula Kiliari, Anastasia Tsiaili, and Ioannis Pashalidis
The paper presents and discusses radon activity concentrations in Cypriot groundwater systems as a function of the background
lithology and seasonal/meteorological conditions using an airborne radon monitoring system (ARM) after separation of radon
by out-gassing. Radiometric analysis of groundwater samples obtained from non-contaminated systems showed that radon concentration
in groundwaters varies strongly (0.1–10 Bq L−1) depending mainly on the hosting geological matrix but also to lesser degree on atmospheric/meteorological conditions. The
associated excess annual dose has been estimated to range between 10−6 and 10−4 mSv y−1, which is an insignificant contribution to the radiation exposure of the Cypriot population caused by airborne radon (0.5 ± 0.4 mSv y−1).
Authors:C. Papastefanou, M. Manolopoulou, S. Stoulos, A. Ioannidou, and E. Gerasopoulos
Radon concentration measurements were carried out using solid-state nuclear track-etch detectors (SSNTDs) type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, Northern Greece, at 55 km from the city of Thessaloniki. Radon levels as high as 88 kBq.m-3 (2.38 nCi.l-1) have been recorded inside the cave equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were performed using TL dosimeters, type TLD-200 (CaF2-Dy) in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy.h-1 were recorded inside the cave. In interpreting the high levels of radiation doses, radioactivity measurements regarding the naturally occurring 238U, 232Th and 40K radionuclides were carried out in various speleothems found at different sites in the cave.
Authors:T. Ishikawa, S. Tokonami, S. Yoshinaga, and Y. Narazaki
A preliminary survey of airborne and waterborne radon concentrations was given for an area where groundwater is used as a
source of public water supply. The average of the waterborne radon concentrations was 77 Bq/l for 36 samples and that of airborne
radon concentrations was 18 Bq/m3for ten houses. It is concluded that the exposure dose due to radon-in-water is likely to be much smaller than the total dose
from natural radiation.
Authors:S. Selvasekarapandian, R. Sivakumar, N. Manikandan, V.M. Ragjunath, V. Kannan, and S. Rajaram
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.
Radon concentration in basements of old buildings in the oldest towns of Lublin region (Zamo
, Chelm and Sandomierz) was determined. Two techniques were applied: passive (Pico-rad) and alpha-spectrometry for radon progeny concentration measurement (SILENA). It was found that only 7% of results exceeded a dose limit of 400 Bq·m-3, established for old buildings. Radon concentration levels ranged from 0.2 to 5150 Bq·m-3. Distribution of the results satisfied a log-normal relationship. Applying these two methods at the same time, the radioactive equilibrium factor of radon and its progeny was determined. In the underground ways, open for visitors, no higher radon concentration was observed.
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.
Authors:G. Espinosa, J. Golzarri, A. Angeles, F. Juárez, T. Martínez, and M. Navarrete
The preliminary results of indoor radon concentration measurements taken in some of Mexico City’s colonial churches and convents
are presented. Measurements were taken in the churches of Santa Catarina, La Conchita, San Juan Bautista, San Antonio Panzacola,
San Diego and San Mateo and the church and convent complex of El Carmen. These structures are all located in Coyoacan, a borough
of Mexico City. Indoor radon concentrations in churches and convents constructed in the 17th and 18th centuries are interesting
for several reasons. Most of these buildings were built using the stones of ancient Mexican pyramids, mainly blocks of basalt
and volcanic pyroclastic rocks, and possess walls between 40 cm and 70 cm thick and naves with large volumes of air and relative
low ventilation. The churches are public places with people most of the time. The indoor radon concentrations were measured
using nuclear track detectors consisting of a closed-end cup containing CR-39 Lantrack® polymer as detector material. The
measurements were taken over four periods of three consecutive months. The results show indoor radon concentrations of between
82 and 165 Bq·m−3, below to the United States Environmental Protection Agency (USEPA) indoor radon action level for workplaces. Using these
results, the radiological risks were calculated and found to be negligible.