Sustainable Water Resources Management

, Volume 5, Issue 4, pp 1525–1536 | Cite as

Isotopes and geochemistry to assess shallow/thermal groundwater interaction in a karst/fissured-porous environment (Portugal): a review and reinterpretation

  • J. M. MarquesEmail author
  • C. Matos
  • P. M. Carreira
  • M. O. Neves
Original Article


As a distinctive fingerprint of the groundwater sources and water–rock interaction within a karst/fissured-porous environment, isotopic (e.g. δ13C, δ18O, δ34S, 3H, and 14C) and geochemical data have been used to establish flow paths (diffuse flow) of thermal waters used in Caldas da Rainha Spa (Portuguese mainland). These thermal waters (T ≈ 32 °C) discharge from springs and boreholes located close to an N–S-oriented oblique fault (60°E). This hydrothermal system is dominated by deep karst/fissured-porous Lower Jurassic carbonate formations containing slow flowing groundwater. 14C determinations in the total dissolved inorganic carbon (TDIC) indicate a mean “age” of about 1600 years BP for the thermal waters. The HCO3, Ca2+, and Mg2+ signatures are related to water/calcite–dolomite interaction, whereas Na+, Cl, and SO42− concentrations are mainly associated with halite and gypsum dissolution. δ18O values indicate that the hydrothermal aquifer system is depleted in heavy isotopes comparing to the shallow aquifer systems, signifying that the main recharge must be related to the Lower Jurassic carbonate formations of the Candeeiros Mountain. The δ13C values measured in the TDIC are typical of carbonate dissolution enhanced by CO2 soil air dissolution. The δ34Ssulphate and δ18Osulphate values of the thermal waters indicate that the sulphate is clearly the result of water–rock interaction with evaporitic layers at depth. Considering a mean geothermal gradient in the region of about 30 °C/km, the silica and K2/Mg geothermometry seems to indicate more reliable circulation depths (1–2 km) for the thermal waters than the SO42−–H2O isotope geothermometer (3–5 km depth). The lack of mixing evidences between the thermal and the local shallow cold groundwaters indicates that both water sources are distinct. Furthermore, increasing knowledge on the local/regional hydrogeology is extremely important to achieve the sustainable use of such “invisible” georesources, since most thermal and mineral waters from karst aquifers worldwide are used both as a source of bottled water and a recreational resource (spa facilities, tourism, etc.).


Thermal waters Karst environment Shallow groundwaters Stable isotopes Geochemistry Central Portugal 



This study was proposed and funded by the Ministry of Health/Centro Hospitalar das Caldas da Rainha/Portugal, under the Research Contract HIDROCALDAS No. 1577. CERENA/IST thankfully acknowledges the FCT support through the UID/ECI/04028/2013 Project, and C2TN/IST gratefully acknowledges the FCT support through the UID/Multi/04349/2013. The authors would like to acknowledge Dr. Henrique Graça, Technical Director of Caldas da Rainha Spa, for all the support during field work campaigns and for helping the drawing of the geological sketch map of the study region. Some of the figures were improved by José Teixeira and Helder Chaminé and we thank them both.


  1. Abusaada M, Sauter M (2013) Studying the flow dynamics of a karst aquifer system with an equivalent porous medium model. Groundwater 51(4):641–650Google Scholar
  2. Aggarwal PK, Araguas-Araguas L, Choudhry M, van Duren M, Froehlich K (2014) Lower groundwater 14C age by atmospheric CO2 uptake during sampling and analysis. Groundwater 52(1):20–24Google Scholar
  3. Albu M, Banks D, Nash N (1997) Mineral and thermal groundwater resources. Chapman and Hall, LondonGoogle Scholar
  4. Anaya AA, Padilla I, Macchiavelli R, Vesper DJ, Meeker JD, Alshawabkeh AN (2014) Estimating preferential flow in karstic aquifers using statistical mixed models. Groundwater 52(4):584–596Google Scholar
  5. Carpenter SR, Caraco NF, Correl DL, Howarh RW, Sharpley AN, Smith VH (1998) Nonpoint pollution of surface waters with phosphorous and nitrogen. Ecol Appl 8:559–568Google Scholar
  6. Correia A, Ramalho EC (2010) Update heat flow density map for Portugal. Proceedings world geothermal congress 2010:7Google Scholar
  7. Criss R, Davisson L, Surbeck H, Winston W (2007) Isotopic methods. In: Goldscheider N, Drew D (eds) Methods in karst hydrogeology. Taylor & Francis, London, pp 123–145Google Scholar
  8. Delbart C, Barbecot F, Valdes D, Tognelli A, Fourre E, Purtschert R, Couchoux L, Jean-Baptiste P (2014) Investigation of young water inflow in karst aquifers using SF6–CFC–3H/He–85Kr–39Ar and stable isotope components. Appl Geochem 50:164–176Google Scholar
  9. DL 306/2007 (2007) Portuguese legislation on water quality (Decreto Lei 306/2007). Diário da República, 1ª série—N.º 164–27 de Agosto de 2007 (in Portuguese)Google Scholar
  10. Dotsika E, Poutoukis D, Kloppmann W, Guerrot C, Voutsa D, Kouimtzis TH (2010) The use of O, H, B, Sr and S isotopes for tracing the origin of dissolved boron in groundwater in Central Macedonia, Greece. Appl Geochem 25:1783–1796Google Scholar
  11. Dowgiallo J, Halas S, Porowski A (2005) Isotope temperature indicators of thermal waters in South-Western Poland. Proceedings world geothermal congress 2005:8Google Scholar
  12. Epstein S, Mayeda T (1953) Variations of 18O content of waters from natural sources. Geochim Cosmochim Acta 4:213–224Google Scholar
  13. Erőss A, Mádl-Szőnyia J, Surbeckb H, Horváthc Á, Goldscheider N, Csomae AÉ (2012) Radionuclides as natural tracers for the characterization of fluids in regional discharge areas, Buda Thermal Karst, Hungary. J Hydrol 426–427:124–137Google Scholar
  14. Field MS (1993) Karst hydrology and chemical contamination. United States Environmental Protection Agency, Washington, [EPA/600/J-93/510 (NTIS PB94135134)] Google Scholar
  15. Field MS (2006) Tracer-test design for losing stream–aquifer systems. Int J Speleol 35:25–36Google Scholar
  16. Freeze RA, Cherry JA (1979) Groundwater. Prentice-Hall, Englewood CliffsGoogle Scholar
  17. Friedman I (1953) Deuterium content of natural waters and other substances. Geochim Cosmochim Acta 4:89–103Google Scholar
  18. Geyh MA (2000) Environmental isotopes in the hydrological cycle. Technical documents in hydrolology 39 (IV)—groundwater. UNESCO, ParisGoogle Scholar
  19. Goldscheider N, Drew D (2007) Methods in karst hydrogeology. Taylor & Francis Group, LondonGoogle Scholar
  20. Goldscheider N, Mádl-Szőnyi J, Erőss A, Schill E (2010) Review: thermal water resources in carbonate rock aquifers. Hydrogeol J 18(6):1303–1318Google Scholar
  21. Gonfiantini R, Zuppi GM (2003) Carbon isotope exchange rate of DIC in karst groundwater. Chem Geol 197:319–336Google Scholar
  22. Hem JD (1970) Study and interpretation of the chemical characteristics of natural water. In: Geological survey water, 2nd edn. United States Department of the Interior. Washington, USAGoogle Scholar
  23. Horvatincic N, Srdoc D, Krajcar Bronic I, Pezdic J, Kapelj S, Sliepcevic A (1996) A study of geothermal waters in northwest Croatia and east Slovenia. Isotopes Water Res Manag IAEA 2:470–474Google Scholar
  24. IAEA [International Atomic Energy Agency] (1976) Procedure and technique critique for tritium enrichment by electrolysis at IAEA laboratory. Technical procedure 19, International Atomic Energy Agency, ViennaGoogle Scholar
  25. IAEA [International Atomic Energy Agency] (1981) Stable isotope hydrology. Deuterium and Oxygen-18 in the water cycle. IAEA, Vienna, Austria, Technical reports series 210Google Scholar
  26. IGM [Instituto Geológico e Mineiro] (1998) Recursos geotérmicos em Portugal Continental. Baixa entalpia. Direcção de Serviços de Gestão e Recursos Geológicos, Divisão de Recursos Hidrogeológicos e Geotérmicos, LisboaGoogle Scholar
  27. Kendall C, McDonnell JJ (1998) Isotope tracers in catchment hydrology. Elsevier, AmsterdamGoogle Scholar
  28. Krouse HR, Mayer B (2001) Sulphur and oxygen isotopes in sulphate. In: Cook P, Herczeg AL (eds) Environmental tracers in subsurface hydrogeology, 2nd edn. Kluwer Academic Publishers, Boston, pp 195–231Google Scholar
  29. Lewis J (2012) The application of ecohydrological groundwater indicators to hydrogeological conceptual models. Groundwater 50(5):679–689Google Scholar
  30. Lloyd RM (1968) Oxygen isotope behavior in the sulphate-water system. J Geophys Res 73:6099–6110Google Scholar
  31. Marques JM (2007) Portugal: um dos países mais ricos da Europa em termalismo. Veiga da Cunha Serra L, Vieira da Costa A, Ribeiro J, Proença L de Oliveira R (eds) Reflexos de Água, Livro Comemorativo dos 30 anos da Associação Portuguesa dos Recursos Hídricos (APRH), Lisboa, pp 80–81 (in Portuguese) Google Scholar
  32. Marques JM, Graça H, Carreira PM, Matias MJ, Graça RC, Nunes D (2007) Updating Caldas da Rainha thermomineral waters conceptual model (Central Portugal): a preliminary isotopic (18O, 2H and 3H) approach. In: Marques JM, Chambel A, Ribeiro L (eds) Proceedings of the symposium on thermal and mineral waters in hard rock terrains, pp 131–144Google Scholar
  33. Marques JM, Graça H, Eggenkamp HGM, Carreira PM, Matias MJ, Mayer B, Nunes D, Trancoso VN (2009) Karst groundwater quality based on geochemical and isotopic tracers: Caldas da Rainha thermomineral water system (Central Portugal). Proceedings of the 2nd international multidisciplinary conference on hydrology and ecology “HydroEco 2009”, Vienna, Austria, pp 75–78Google Scholar
  34. Marques JM, Graça H, Eggenkamp HGM, Carreira PM, Mayer B, Nunes D (2012) Contribuição de traçadores geoquímicos e isotópicos para a avaliação das águas termais das Caldas da Rainha. Comun Geol 99(2):43–51Google Scholar
  35. Marques JM, Graça H, Eggenkamp HGM, Neves O, Carreira PM, Matias MJ, Mayer B, Nunes D, Trancoso VN (2013) Isotopic and hydrochemical data as indicators of recharge areas, flow paths and water-rock interaction in the Caldas da Rainha—Quinta das Janelas thermomineral carbonate rock aquifer (Central Portugal). J Hydrol 476:302–313Google Scholar
  36. Martin JB, Kastner M, Henry P, Le Pichon X, Lallement S (2012) Chemical and isotopic evidence for sources of fluids in a mud volcano field seaward of the Barbados accretionary wedge. J Geophys Res. doi: 10.1029/96JB00140 CrossRefGoogle Scholar
  37. Mayer B, Krouse HR (2004) Procedures for sulphur isotope abundance studies. In: de Groot P (ed) In: Handbook of stable isotope analytical techniques. Elsevier, Amsterdam, pp 538–596Google Scholar
  38. Mizutani Y, Rafter TA (1969) Oxygen isotopic composition of sulphates, part 3: Oxygen isotopic fractionation in the bisulphate ion-water system. NZ J Sci 12:54–59Google Scholar
  39. Pu T, Hea Y, Zhanga T, Wua J, Zhuc G, Changa L (2013) Isotopic and geochemical evolution of ground and river waters in a karst dominated geological setting: a case study from Lijiang basin, South-Asia monsoon region. Appl Geochem 33:199–212Google Scholar
  40. Ravbar N, Goldscheider N (2009) Comparative application of four methods of groundwater vulnerability mapping in a Slovene karst catchment. Hydrogeol J 17(3):725–733Google Scholar
  41. Reed MH, Spycher NF (1984) Calculation of pH and mineral equilibria in hydrothermal waters with application to geothermometry and studies of boiling and dilution. Geochim Cosmochim Acta 48:1479–1492Google Scholar
  42. Rezaei A, Zare M, Raeisi E, Ghanbari RN (2013) Interaction of a fresh water lake and a karstic spring via a syncline fold. Groundwater 51(2):305–312Google Scholar
  43. Ryan M, Meiman J (1996) An examination of short-term variations in water quality at a karst spring in Kentucky. Groundwater 34(1):23–30Google Scholar
  44. Schmidt H, Balke KD (1980) Possibilities for artificial groundwater recharge and storage in Germany. Z Dtsch Geol Ges 131:93–109Google Scholar
  45. Schmidt H, Balke KD (1985) Standards and laws of artificial groundwater recharge in Germany. Environmental Office, UBA-FB, Berlin, pp 80–179 (German) Google Scholar
  46. Sharma BR (1997) Environmental and pollution awareness. Technical India Publications, New DelhiGoogle Scholar
  47. Tanweer A (1990) Importance of clean metallic zinc for hydrogen isotope analysis. Anal Chem 62:2158–2160Google Scholar
  48. UNESCO-WWAP (2006) Water: a shared responsibility. The United Nations world water development report 2, UNESCO, ParisGoogle Scholar
  49. Verbovšek T, Kanduč T (2016) Isotope Geochemistry of groundwater from fractured dolomite aquifers in Central Slovenia. Aquat Geochem 22(2):131–151Google Scholar
  50. White WB (1969) Conceptual models for carbonate aquifers. Groundwater 7(3):15–21Google Scholar
  51. White WB (2012) Conceptual models for carbonate aquifers. Groundwater 50(2):180–186Google Scholar
  52. Zbyszewski G (1959) Étude structurale de la vallée typhonique de Caldas da Rainha (Portugal). Memórias dos Serviços. Geológicos de Portugal 3:1–184Google Scholar
  53. Zbyszewski G, Moitinho de Almeida F (1960) Carta Geológica de Portugal, escala 1/50,000. Notícia Explicativa da Folha 26-D—Caldas da RainhaGoogle Scholar
  54. Zhang K, Wen Z, Xhang X (2001) China’s water environment at the beginning of the 21st century: challenges and countermeasures. Water Sci Technol 46(11–12):245–251Google Scholar
  55. Zhao L, Xiao H, Dong Z, Xiao S, Zhou M, Cheng G, Yin L, Yin Z (2012) Origins of groundwater inferred from isotopic patterns of the Badain Jaran Desert, Northwestern China. Groundwater 50(5):715–725Google Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  1. 1.CERENA, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal
  2. 2.Faculdade de Ciencias, Instituto Dom LuizUniversidade de LisboaLisbonPortugal
  3. 3.Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior TécnicoUniversidade de LisboaBobadela LRSPortugal

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