Radon levels assessment in some Northern Romanian salt mines

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 A degrees 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 +/- A 0.39 and 96.5 +/- A 4.76 Bq/m(3)) demonstrated the best suitability of the investigated three salt mines in Romania for speleotherapeutic applications.