Assessment of indoor radon levels in Portuguese thermal spas

Abstract

The concentration of radon was assessed in the indoor air of 14 thermal spas and in the home of a selected worker from each thermal spa. The measurements of the indoor radon concentration were carried out using CR-39 detectors, placed in both the workplaces and workers' homes, exposed for an average period of 45 days, in different seasons of the year. For the thermal spas, the indoor radon concentration ranged between 73 and 4335 Bq m −3 , with a geometric mean of 445 Bq m −3 and an arithmetic mean of 687 Bq m −3 , and within the workers' homes ranged between 68 and 4051 Bq m −3 , with a geometric mean of 410 Bq m −3 and an arithmetic mean of 785 Bq m −3. The annual effective doses due to radon inhalation were calculated considering two different exposure scenarios for the thermal spas. For the worst-case scenario, assuming that workers do not have job rotation, the values varied between 1 and 31 mSv y −1 , while for an exposure scenario considering job rotation, the calculated dose ranged between 0.6 and 16 mSv y −1. For workers' homes, the calculated dose ranged between 2 and 102 mSv y −1. The results showed that the EU reference level of 300 Bq m −3 (Directive 2013/59/EURATOM) was exceeded in several cases. In 36% of the thermal spas the exposure of the workers is likely to exceed the effective dose of 6 mSv y −1 and in this case, according to the Directive, it should be considered as "a planned exposure situation".

Variability of Indoor Radon Level Accumulation: A Study in Portuguese Thermal Spas

“…2). These detectors comprise a small piece of polycarbonate, highly sensitive to ionizing particle tracks such as alpha particles [30].…”

“…Therefore, the dose was calculated with the most conservative value of each input [30], meaning that a hypothetical situation was considered in which everything that contributes to the exposure was maximized, namely the exposure time (2000 h/y) and indoor radon concentration (maximum value) [32].…”

“…For the same region, the indoor radon concentration may be affected by the variation of the construction materials used for building while other factors remain constant (such as pressure differential, weather and climate, etc.) [11,14]. At the same time, routine habits and lifestyle of the population may be very different, which makes it extremely difficult to relate all the parameters, quantify and interpret the variability of indoor radon concentration.…”

Indoor radon activity concentration and effective dose rates at schools and thermal spas of Ilgin

“…In door ra don ac tiv ity mea sure ments are very impor tant in school build ings, as well as all in door en vi ronment where peo ple live, in or der to de ter mine the ra don ex po sure of stu dents, teach ers and staff. Such sur veys have been car ried out in schools and ther mal spas in Turkey [9,10] and var i ous coun tries of the world [11][12][13][14][15]. In the pres ent work, we have ob tained the re sults of the indoor ra don ac tiv ity con cen tra tions and the ef fec tive dose rates of ra don ex po sure, mea sured in some schools of Ilg?n dis trict of Konya prov ince.…”