Exposure to radon in the radon spa Niška Banja, Serbia

There is a well-known radon spa Niška Banja in south-east of Serbia. In Niška Banja spa there is a medical complex and radon is used for therapeutic purposes for many different diseases. This paper presents elevated radon levels in the Niška Banja spa. Indoor radon and radon in water activity concentration measurements in thermal pools and therapy rooms are presented. There are also results from gamma spectrometry measurements of soil, rock and therapy mud. A special attention is paid to the medical staff exposure to radon around thermal pools. The annual effective doses from radon for staff working around the thermal pools in Niška Banja spa are very high comparing to the maximum recommendation level. The maximal radon concentration of (22.90 ± 0.57) kBq m−3 was measured in the basement of the hotel-dispensary “Radon”. This hotel is settled on “bigar” rock – travertine, which has high content of 226Ra. ► Niška Banja was identified as a high natural radiation area. ► This area is very interesting from geological point of view. ► Indoor radon and radon in water concentration measurements from thermal pools and therapy rooms are presented. ► Gamma spectrometry measurements of soil samples are presented. ► Occupational doses for medical and non-medical staff who work around thermal pools are very high.