Radon and thoron levels in air at selected places in Georgia

Abstract

Radon (222Rn) and thoron (220Rn) in air were monitored in a tunnel, and several dwellings, public buildings and spas in Tbilisi, and in the Sataplia and Prometheus caves, using an RTM 1688-2 Radon/Thoron Monitor (SARAD, Germany). While measurement at each point in the cave lasted 20–30 minutes, it did about a day at other places, in order to see the diurnal variations. Highest radon and thoron activity concentrations were found in the Sataplia Cave, being 3094 ± 340 Bq m–3and 347 ± 239 Bq m–3, respectively. Lower values were in the Prometheus Cave (1472 ± 236 Bq m–3 and 144 ± 88 Bq m–3) and at a swimming pool in the Tskaltubo Health Resort (1110 ± 115 Bq m–3 and 681 ± 475 Bq m–3), and were below 200 Bqm–3 elsewhere. Thoron/radon activity ratios ranged from 0.03 to 0.17 in the caves and were in the range of 0.09–0.90 at other places, the highest value found in a monk room in the Vardzia-Cave monastery.