VARIABILITY OF INDOOR RADON LEVEL ACCUMULATION: A STUDY IN PORTUGUESE THERMAL SPAS

1. VARIABILITY OF INDOOR RADON LEVEL ACCUMULATION: A STUDY IN PORTUGUESE THERMAL SPAS • S. Silva & M.L. Dinis • 12 a 16 June de 2017

2. Índice 1. Introduction 2. MaterialsandMethods • Studyarea • Samplingplan • Measurementmethods 3. Resultsanddiscussion • Indoor radonconcentration • Dose assessment 4. Conclusions

3. 1. Introduction Natural radioactivity

4. 1. Introduction Effects on human health Radon is currently recognized as the leading cause of lung cancer, with the exception of tobacco.

5. 1. Introduction Radon origin

6. 1. Introduction Radon origin The radon concentration depends on:

7. 1. Introduction Geological setting In Portugal, thegeologicalsettings are mostlycomprisedofgranite rockswithuraniummineralization.

8. 1. Introduction Legislation

9. 1. Introduction Theaimofthisworkwas to assesstheexposure to indoor radonbymeasuringtheconcentrationofthe indoor radon in 16 Portuguese thermal spas (38% ofthethermal spas in Portugal) andevaluateitsvariabilitywithineachestablishment as well as itscontribution to theeffective dose.

10. 2. MaterialsandMethods

11. 2. Materials and Methods Thermal spas C. Felgueira C. Manteigas C. Rainha C. Taipas T. S. Lourenço T. Cró T. Caldelas T. Alcafache C. Saúde T. Longroiva T. Luso T. Moimenta T. Monção T. Sangemil T. S. Pedro do Sul T. Unhais Serra

12. 2. Materials and Methods Figure 1 – CR-39

13. 3. Results ans discussion Figure 2 - Concentration of radon in indoor air by location

14. 3. Results ans discussion Figure 3 - Radon concentration in indoor air versus seasons of the year

15. 3. Results and discussion Figure 4 - Effective dose by thermal spa

16. 4. Conclusion • 88% thermal spas the indoor radon concentration is above the reference level recommended by the EU: • geological setting where the thermal spas are located. • 18% of thermal spas the levels of radon concentration in indoor air were below the reference levels recommended by the EU: • effective ventilation system inside the thermal spa (mechanical ventilation system).

17. 4. Conclusion • 88% thermal spas the indoor radon concentration is above the reference level recommended by the EU: • geological setting where the thermal spas are located. • 18% of thermal spas the levels of radon concentration in indoor air were below the reference levels recommended by the EU: • effective ventilation system inside the thermal spa (mechanical ventilation system).

18. 4. Conclusion • In most thermal spas, the highest results of radon concentration in indoor air were obtained during the winter period because the spaces are less ventilated during this period. • 50% of the thermal spas there is a great variability of the values of the radon concentration in indoor air: • ventilation conditions of the different spaces and it is assumed that radon originates from the subsoil and/or building materials due to the geological setting where these thermal spas are located.

19. 4. Conclusion • 31% of the thermal spas the annual effective dose is > 6 mSv/y: • maintain the effective annual dose of the workers under observation. • 39% of thermal spas, workers face a situation of planned exposure.