Sample design for radon concentration investigation in Bulgarian caves

Ivanova, Kremena and Stojanovska, Zdenka and Djounova, Jana and Kunovska, Bistra and Chobanova, Nina and Djunakova, Decislava (2019) Sample design for radon concentration investigation in Bulgarian caves. In: Seventh international conference on radiation in various fields of research (rad 2019), 10–14 June 2019, Herceg Novi, Montenegro.

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As a very mountainous country, Bulgaria has a lot of caves, but only some of them are developed,
managed and available for tourist visits. The main sources of radon are rocks and a high
concentration can be measured in caves. Caves have been of interest because radon concentration in
these environments may sometimes reach high values. A rather large number of investigations have
been carried out all over the world, from the point of view of both researches on radon behavior in a
cave environment and radiation protection. There are no systematic investigations of radon in the
caves in Bulgaria in order to assess the health risk. The paper presents the sample design of the radon
concentration survey in Bulgarian caves for the evaluation of the health risk of people. The sample
design covers the method of selection, the sample structure and the plan for analyzing and
interpreting the results. The method selected to define the representative sample corresponds to the
following criteria: it covers all types of caves in different mountains in Bulgaria; it is consistent over
time; it includes changes to the definition over time; it constitutes the selection of the sample design
for the caves and organization of survey. The samples of caves are defined on the basis of mountains
in Bulgaria in order for the definitions to remain constant over time. Groups of caves according to the
mountains are: caves in Stara Planina, caves in Rhodope Mountains and caves in other mountains.
The design of the samples of caves is built around a random selection from the most visited caves in
Bulgaria. According public information, there are 65 of these caves. The calculated sample size for a
confidence level of 95% and a margin of error of 30% is 10 caves. The numbers of samples have been
weighed according to the percent of the caves in the groups with 5 per cent precision at 95 per cent
confidence. The way of the selection of the sample and the measurement method is presented in the

Item Type: Conference or Workshop Item (Other)
Subjects: Natural sciences > Physical sciences
Divisions: Faculty of Medical Science
Depositing User: Zdenka Stojanovska
Date Deposited: 03 Feb 2020 13:19
Last Modified: 12 Feb 2020 08:09

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