Exposure to radon in Cuban tourist caves

With the objective of estimating the dose, due to Radon-222, received by tour guides and other people who work inside some of the most important tourist caves in the Republic of Cuba, measurements of radon concentrations were carried out in four of these caves: Santo Tomas Cave, Tapiada Cave, Del Indio Cave and Jose Miguel Cave. All these caves are located in the Vinales Valley (Pinar del Rio City), a very important tourist area in the country. The relationship among radon concentration, the concentration of natural radionuclides inside the caves and the geologic characteristics of the specific locations was analyzed. In order to select the most appropriates measurement places, different criteria were taken into account: representatives points of the geology of the caves, level of gamma radiation, exchange of air, places of work inside the caves (cafeterias, restaurants and shops) and places more frequently visited by tour guides. The maximum radon concentration was found in Jose Miguel Cave with a value of 220 Bq/m3. The measurement of gamma dose rate inside the caves was carried out with a scintillation detector type Scintrex BGS-3 previously calibrated at SSI, Sweden. The radon concentrations were measured with the equipment Alpha Guard PQ2000/MC50 and SARAD RM2000, both also calibrated at SSI, Sweden. The obtained results indicated that, in the studied caves, the annual dose is not greater than 1 mSv considering a work year of 2000 hours. (author)