The influence of geological factors on radon risk in groundwater and dwellings in the region of Amarante (Northern Portugal)


The region of Amarante (Northern Portugal) is composed of Hercynian tardi-tectonics granites and Paleozoic metasediments. Petrographic observations and SEM studies show that uranium is mainly contained within the rock in heavy accessory minerals such as apatite, zircon, monazite, uraninite, thorite and thorianite. The geological, geochemical and radiological data obtained suggest that the radon concentrations in dwellings of the studied area are mainly related with the uranium content of the rocks. Indeed, the highest contents were observed in granite AT2 of Padronelo (18.2 ppm) and the granite AT1 of Telões (10.3 ppm), with metasediments showing much lower uranium contents of 1.6 ppm; radon concentrations were evaluated in dwellings, using CR-39 passive detectors, and the results obtained in winter conditions suggest that the most productive geological units are the granites AT2 and AT1, with geometric means of 430 and 220 Bq/m3, respectively, while the metasediments show the lowest value of 85 Bq/m3. Some moderate radiometric anomalies, where uranium contents can double typical background values, were found in relation with specific fault systems of the region affecting granitic rocks, thus increasing radon risk; this is an indication of uranium mobility, likely resulting from the leaching of primary mineral supports as uraninite. Groundwater radionuclide contents show a wide range of results, with the highest activities related with granitic lithologies: 2,295 Bq/l for radon, 0.83 Bq/l for gross α and 0.71 Bq/l for gross β, presenting metasediments much lower values, in good agreement with other results obtained. Absorbed dose measured with gamma spectrometers in direct contact with the rocks is directly related with the uranium contents of the rocks, and thus works as a fast proxy for radon risk. It is concluded that radon risk is moderate to high in the granitic areas of the Amarante region and low in the metasediments of the same region.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3


  1. Appleton JD (2005) Radon in air and water. In: Selinus O et al (eds) Essentials of medical geology. Elsevier Academic Press, Amsterdam, p 824

    Google Scholar 

  2. Appleton JD, Miles JCH (2010) A statistical evaluation of the geogenic controls on indoor radon concentrations and radon risk. Environ Radioact 101:799–803

    Article  Google Scholar 

  3. Ball TK, Miles JCH (1993) Geological and geochemical factors affecting the radon concentration in homes in Cornwall and Devon, UK. Environ Geochem Health 15:27–36

    Article  Google Scholar 

  4. Beetsma JJ (1995) The late Proterozoic/Paleozoic and Hercynian crustal evolution of the Iberian Massif, N Portugal, as traced by geochemistry and Sr-Nd-Pb isotope systematic of pre-Hercynian terrigenous sediments, and Hercynian granitoids. Protschrift Vrije Universiteit Amsterdam, Nederlands. ISBN 90-9007958-0

    Google Scholar 

  5. Beir VI (1998) Health effects of exposure to radon. Biological Effects of Ionizing Radiation Committee, National Academy of Sciences, US National Academy Press, Washington DC, p 516

    Google Scholar 

  6. Chen J (2009) A preliminary design of radon potential map of Canada: a multi-tier approach. Environ Earth Sci 59:775–782

    Article  Google Scholar 

  7. Darby S et al (2005) Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case control studies. BMJ (published 21 December 2004)

  8. DL no. 79/2006, 4 of April, Indoor air quality, Journal of the Portuguese Republic, Series I no. 67, Ministry of Public Works, Transport and Communications

  9. Gomes MEP, Neves LJPF, Coelho F, Carvalho A, Sousa M, Pereira AJSC (2010) Geochemistry of granites and metasediments of the urban area of Vila Real (Northern Portugal) and correlative radon risk. J Environ Earth Sci 64(2):497–502

    Article  Google Scholar 

  10. Gonçalves CVM, Pereira AJSC (2007) Radionuclides in groundwater of the Serra do Buçaco region (Portugal). In: Proceedings of the XXXV congress of the international association of hydrogeologists, Lisbon

  11. Kemski J, Siehl A, Stagemann R, Valdivia-Manchego M (2001) Mapping the geogenic radon potential in Germany. Sci Total Environ 272(217–230):364

    Google Scholar 

  12. Kemski J, Klingel R, Siehl A, Valdivia-Manchego M (2009) From radon hazard to risk prediction-based on geological maps, soil gas and indoor measurements in Germany. Env. Geol 36756:1269–1279

    Article  Google Scholar 

  13. Miles JCH, Ball TK (1996) Mapping radon-prone areas using house radon data and geological boundaries. Environ Int 22(Suppl. 1):779–782 371

    Article  Google Scholar 

  14. Minda M, Tóth G, Horváth I, Barnet I, Hámori K, Tóth E (2009) Indoor radon mapping and its relation to geology in Hungary. Environ Geol 57(3):601–609

    Article  Google Scholar 

  15. Neves LJPF, Avelans SCC, Pereira AJSC (2003) Variação sazonal do gásradão em habitações da área urbana da Guarda (Portugal Central). Actas do IV Congresso Ibérico de Geoquímica. (XIII Semana de Geoquímica), Coimbra, pp 307–309

  16. Pereira E (1989) Explaining Notice from Sheet 10 A—Celorico de Basto. Geological Survey of Portugal, Lisbon

    Google Scholar 

  17. Pereira AJSC, Neves LJPF, Costa LAPA, Godinho MM (1999) Soil gas radon potential in two urban areas of central Portugal. Il Nuovo Cimento 22C(3–4):615–620

    Google Scholar 

  18. Pereira AJSC, Godinho MM, Neves LJPF (2010) On the influence of faulting on small-scale soil-gas radon variability: a case study in the Iberian Uranium Province. J Environ Radioact 101(875–882):381

    Google Scholar 

  19. Shi X, Hoftiezer DJ, Duell EJ, Onega TL (2006) Spatial association between residential radon concentration and bedrock types in New Hampshire. Env Geol 51:65–71

    Article  Google Scholar 

  20. Singh S, Mehra R, Singh K (2005) Seasonal variation of indoor radon in dwellings of Malwa region, Punjab. Atmospheric Environ 39(40):7761–7767

    Article  Google Scholar 

  21. Sundal AV, Henriksen H, Soldal O, Strand T (2004) The influence of geological factors on indoor radon concentrations in Norway. Sci Total Environ 328:41–53

    Article  Google Scholar 

  22. UNSCEAR (2008) Sources and effects of ionizing radiation. United Nations, New York, p 472

    Google Scholar 

  23. WHO (World Health Organization) (2009) In: Zeeb H, Shannoun F 390 (eds) Handbook on indoor radon: a public health perspective. 391WHO Press, Geneva, p 110

Download references

Author information



Corresponding author

Correspondence to M. E. P. Gomes.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Martins, L.M.O., Gomes, M.E.P., Neves, L.J.P.F. et al. The influence of geological factors on radon risk in groundwater and dwellings in the region of Amarante (Northern Portugal). Environ Earth Sci 68, 733–740 (2013).

Download citation


  • Radon
  • Geochemistry
  • Uranium
  • Amarante