Occupational Safety and Hygiene IV
Radon is the most significant source of exposure to naturally occurring radionuclides which may be found in indoor environments, such as homes and workplaces. It is naturally present in soils, rocks and in thermal mineral waters. Thermal spas are one of the professional sectors with potential for exposure to radon in large part due to the inhalation of radon released from thermal waters. In this study, an assessment of indoor radon concentration and gamma dose rates were carried out in 16 thermal spas of Portugal. Indoor gamma dose rates measurements were made using a Geiger counter (Gamma Scout-GS3) and radon measurements were carried out using CR-39 detectors. The detectors were exposed for an extended period of time representing two seasonal periods in a year, both in the selected thermal spas and in worker's dwellings. The results showed that gamma doses rates are generally low but, in several cases, radon concentration exceeded national as well as international standard, namely the reference level recommended by Directive 2013/59/EURATOM (300 Bq/m3) and the threshold for protection (400 Bq/m3) from the Portuguese legislation. In addition, the results also showed that in some situations, radon concentrations in residential environments are higher than in the selected thermal spas. The annual effective doses deriving from external radiation (gamma dose rates) and indoor radon showed the need to implement measures to optimize the radiation protection of the workers against ionizing radiation and also the need to adopt mitigation measures of radon concentration in the residential environments. © 2016 Taylor & Francis Group, London, UK.
Year of publication: 2016