Study of 222Rn continuous monitoring time series and dose assessment in six European caves

The present work aims to assess the effective doses from long-term continual radon monitoring in six European caves (Slovenia, Slovakia and the Czech Republic), including influencing environmental factors. Caves are important radiation protection subjects because of elevated radon activity concentration (∼kBq/m3), mostly due to the low natural ventilation. The sources of radon gas are most often underground rock layers and clastic sediments. The radon activity concentrations show seasonal variations, for which the outside temperature is the main driving force. The human health impact due to the radon inhalation in monitored caves was estimated through the annual effective dose, using the methodology provided by the International Commission on Radiological Protection (ICRP Publication 137). The annual effective dose could reach several tens of mSv, depending on the working hours spent in the underground.