Radon activity levels and effective doses in the Perama Cave, Greece.

An investigation of atmospheric radon levels in the Perama Cave, North-western Greece, has been carried out using CR-39 detectors. The detectors were placed at various locations along the guided cave pathway and exposed during different sampling periods. Mean concentrations amounting to 925 +/- 418 and 1,311 +/- 352 Bq m-3 were recorded in the summer and winter months, respectively. As the Perama Cave is one of the most popular in Greece, attracting more than 85,000 tourists per year, the quantification of effective doses to staff and visitors was an issue of importance. Doses less than 5.1 microSv per visit were calculated for tourists and around 1.8 mSv y-1 for seasonal guides, employed for periods of high visiting frequency. The annual exposure of permanent guides was estimated to fall between 3 and 10 mSv, which is the range of action levels recommended by the ICRP.