Estimation of effective doses to cavers based on radon measurements carried out in seven caves of the Bakony Mountains in Hungary

Nowadays, as the practice of extreme sports is spreading, potholing is becoming more and more popular. As a result, both the number of cavers and the time spent in the caves have been on the rise. There are some cavers known to have spent some 5000 h in caves over a span of 10 years. In poorly ventilated caves, radon exhalated from cave rocks and deposits may accumulate and cause significant doses to cavers. In this study, the radon concentration in seven caves in the Bakony Mountains, Hungary, was measured by continuous and integrated measurement devices. Measured values for the different caves were rather different, and varied between 50 and 24,000 Bq m-3. The average radon concentration over the measurement period was approximately 10,000 Bq m-3 in five of the seven caves inspected. By assuming an average of 470 h year-1 spent in caves, effective doses to cavers were estimated. The expected annual effective dose, in case of an equilibrium factor of 0.6, was 19.7 mSv.