Hydrogeochemical and isotopic tracers for identification of seasonal and long-term over-exploitation of the Pleistocene thermal waters

  • Nina RmanEmail author


The aim of the study was to develop and test an optimal and cost-effective regional quality monitoring system in depleted transboundary low-temperature Neogene geothermal aquifers in the west Pannonian basin. Potential tracers for identification of seasonal and long-term quality changes of the Pleistocene thermal waters were investigated at four multiple-screened wells some 720 to 1570 m deep in Slovenia. These thermal waters are of great balneological value owing to their curative effects and were sampled monthly between February 2014 and January 2015. Linear correlation and regression analyses, ANOVA and Kolmogorov–Smirnov two-sample test for two independent samples were used to determine their seasonal and long-term differences. Temperature, pH, electrical conductivity, redox potential and dissolved oxygen did not identify varying inflow conditions; however, they provided sufficient information to distinguish between the four end-members. Characteristic (sodium) and conservative (chloride) tracers outlined long-term trends in changes in quality but could not differentiate between the seasons. Stable isotopes of δ 18O and δ 2H were used to identify sequential monthly and long-term trends, and origin and mixing of waters, but failed to distinguish the difference between the seasons. A new local paleo-meteoric water line (δ 2H = 9.2*δ 18O + 26.3) was outlined for the active regional groundwater flow system in the Pannonian to Pliocene loose sandstone and gravel. A new regression line (δ 2H = 2.3*δ 18O–45.2) was calculated for thermomineral water from the more isolated Badenian to Lower Pannonian turbiditic sandstone, indicating dilution of formation water. Water composition was generally stable over the 1-year period, but long-term trends indicate that changes in quality occur, implying deterioration of the aquifers status.


Geothermal aquifer Quality monitoring Stable isotopes Aquifer depletion Slovenia Pannonian basin 



Research was supported by the SI MIZŠ and the ESF OP Human Resources Development Program 2007–2013, PA 1, M 1.1, Contract No. 3330-14-509001, and the SI ARRS Programme group P1-0020 Groundwaters and Geochemistry. Investigation could not be performed without kind permission of owner of the wells, Sava Turizem d.d., and their helpful staff, M. Šutar and L. Šmigoc in Terme Ptuj, and S. Smodiš and P. Trajbarič in Terme 3000. Author also thanks M. Hoetzl for field support and S. Mozetič for graphics.


  1. Anonymous (2004). Rules on natural mineral water, spring water and table water, and Rules on its modification and supplements (in Slovenian). Official Gazette of R Slovenia, 50/2004, 75/2005, 6761–6772, 8039.Google Scholar
  2. Appleyard, S., & Cook, T. (2009). Reassessing the management of groundwater use from sandy aquifers: acidification and base cation depletion exacerbated by drought and groundwater withdrawal on the Gnangara Mound, Western Australia. Hydrogeology Journal, 17, 579–588. doi: 10.1007/s10040-008-0410-2.CrossRefGoogle Scholar
  3. Arnorsson, S. (2000). Isotopic and chemical techniques in geothermal exploration, development and use: sampling methods, data handling, interpretation. Vienna: IAEA. 351 p.Google Scholar
  4. Axelsson, G. (2000). Sedimentary geothermal systems in China and Europe. In G. Axelsson & E. Gunnlaugsson (Eds.), Long-term monitoring of high- and low-enthalpy fields under exploitation (pp. 203–221). Auckland: Kokonoe, IGA.Google Scholar
  5. Axelsson, G., & Gunnlaugsson, E. (2000). Long-term monitoring of high- and low-enthalpy fields under exploitation. Auckland: Kokonoe, IGA. 226 p.Google Scholar
  6. Axelsson, G., Gunnlaugsson, E., Jónasson, T., & Ólafsson, M. (2010). Low-temperature geothermal utilization in Iceland—decades of experience. Geothermics, 39, 329–338. doi: 10.1016/j.geothermics.2010.09.002.CrossRefGoogle Scholar
  7. Barna, G., Fórizs, I. (2007). Stable hydrological characteristics of the Balaton lake. Spatial distribution and evaporative isotope effect (in Hungarian). Hidrológiai Közlöny, 35–41.Google Scholar
  8. Bräuer, K., Geissler, W. H., Kämpf, H., Niedermannn, S., & Rman, N. (2016). Helium and carbon isotope signatures of gas exhalations in the westernmost part of the Pannonian Basin (SE Austria/NE Slovenia): evidence for active lithospheric mantle degassing. Chemical Geology, 422, 60–70. doi: 10.1016/j.chemgeo.2015.12.016.CrossRefGoogle Scholar
  9. Butler, J.J., Tsou, M.-S. (2003). Pumping-induced leakage in a bounded aquifer: an example of a scale-invariant phenomenon. Water Resources Research, 39. doi: 10.1029/2002WR001484
  10. Buzek, F., & Michaliček, M. (1997). Origin of formation waters of S-E parts of the Bohemian Massif and the Vienna Basin. Applied Geochemistry, 12, 333–343. doi: 10.1016/S0883-2927(97)00006-1.CrossRefGoogle Scholar
  11. Ceroân, J. C., & Pulido-Bosch, A. (1999). Geochemistry of thermomineral waters in the overexploited Alto Guadalentiân aquifer (South-East Spain). Water Resources, 33, 295–300.Google Scholar
  12. Chen, L.-W., Gui, H.-R., & Yin, X.-X. (2011). Monitoring of flow field based on stable isotope geochemical characteristics in deep groundwater. Environmental Monitoring and Assessment, 179, 487–498. doi: 10.1007/s10661-010-1751-6.CrossRefGoogle Scholar
  13. Clark, I., & Fritz, P. (1997). Environmental isotopes in hydrogeology (pp. 1–312). USA: CRC Press.Google Scholar
  14. Conti, A., Sacchi, E., Chiarle, M., Martinelli, G., & Zuppi, G. M. (2000). Geochemistry of the formation waters in the Po plain (Northern Italy): an overview. Applied Geochemistry, 15, 51–65.CrossRefGoogle Scholar
  15. Craig, H. (1961). Isotopic variations in meteoric waters. Science, 133, 1702–1703.CrossRefGoogle Scholar
  16. Custodio, E. (2002). Aquifer overexploitation: what does it mean? Hydrogeology Journal, 10, 254–277. doi: 10.1007/s10040-002-0188-6.CrossRefGoogle Scholar
  17. Dansgaard, W. (1964). Stable isotopes in precipitation. Tellus, 16, 436–468.CrossRefGoogle Scholar
  18. Druschel, G. K., & Rosenberg, P. E. (2001). Non-magmatic fracture-controlled hydrothermal systems in the Idaho Batholith: South Fork Payette geothermal system. Chemical Geology, 173, 21. doi: 10.1016/S0009-2541(00)00280-1.CrossRefGoogle Scholar
  19. Duan, Z., Pang, Z., & Wang, X. (2011). Sustainability evaluation of limestone geothermal reservoirs with extended production histories in Beijing and Tianjin, China. Geothermics, 40, 125–135. doi: 10.1016/j.geothermics.2011.02.001.CrossRefGoogle Scholar
  20. EC (2000). Directive 2000/60/EC of the European Parliament and of the Council establishing a framework for the community action in the field of water policy (water framework directive). OJ L, 327, 22.12.2000, 237/1-327/72.Google Scholar
  21. EC (2007). Common implementation strategy for the water framework directive (2000/60/EC), guidance document no. 15: guidance on groundwater monitoring. Luxembourg, Office for Official Publications of the European Communities, 54 p.Google Scholar
  22. Epstein, S., & Mayeda, T. (1953). Variation of O18 content of waters from natural sources. Geochimica et Cosmochimica Acta, 4, 213–224.CrossRefGoogle Scholar
  23. Ferjan, T. (2012). Determination of sources of bottled waters, PhD thesis (in Slovenian). Ljubljana, University of Ljubljana.Google Scholar
  24. Fricke, H. C., & O’Neil, J. R. (1999). The correlation between 18O = 16O ratios of meteoric water and surface temperature: its use in investigating terrestrial climate change over geologic time. Earth and Planetary Science Letters, 170, 181–196. doi: 10.1016/S0012-821X(99)00105-3.CrossRefGoogle Scholar
  25. Gallino, S., Bulloz, M., Naffrechoux, E., Dzikowski, M., & Gasquet, D. (2008). The influence of extraction rate on the reduced sulphur content of Aix-les-Bains’ thermal spring waters: consequences for resource-quality monitoring. Applied Geochemistry, 23, 1367–1382. doi: 10.1016/j.apgeochem.2007.11.014.CrossRefGoogle Scholar
  26. Gikas, G. D., Tsihrintzis, V. A., Akratos, C. S., & Haralambidis, G. (2009). Water quality trends in polyphytos reservoir, Aliakmon River, Greece. Environmental Monitoring and Assessment, 149, 163–181. doi: 10.1007/s10661-008-0191-z.CrossRefGoogle Scholar
  27. Goldbrunner, J. E. (2000). Hydrogeology of deep groundwaters in Austria. Mitteilungen. Österreichische Geologische Gesellschaft, 92(1999), 281–294.Google Scholar
  28. Gunnlaugsson, E. (2000). Chemical monitoring. In G. Axelsson & E. Gunnlaugsson (Eds.), Long-term monitoring of high- and low-enthalpy fields under exploitation (pp. 57–76). Auckland: Kokonoe, IGA.Google Scholar
  29. Helsel, D. R., & Hirsch, R. M. (2002). Statistical methods in water resources, Book 4, Chapter A3. USA: USGS. 522 p.Google Scholar
  30. Hochstein, M. P. (1988). Assessment and modelling of geothermal reservoirs (small utilization schemes). Geothermics, 17, 15–49.CrossRefGoogle Scholar
  31. Horváth, F., Musitz, B., Balázs, A., Végh, A., Uhrin, A., et al. (2015). Evolution of the Pannonian basin and its geothermal resources. Geothermics, 53, 328–352. doi: 10.1016/j.geothermics.2014.07.009.CrossRefGoogle Scholar
  32. IAEA/WMO (2015). Global network of isotopes in precipitation. The GNIP database. Accessed 26 July 2015.
  33. Janža, M. (2015). A decision support system for emergency response to groundwater resource pollution in an urban area (Ljubljana, Slovenia). Environment and Earth Science, 73, 3763–3774. doi: 10.1007/s12665-014-3662-2.CrossRefGoogle Scholar
  34. Jelen, B., Rifelj, H. (2011). Surface lithostratigraphic and tectonic structural map of T-JAM project area, northeastern Slovenia, 1:100.000 (in Slovenian). Ljubljana, GeoZS. Accessed 26 July 2015.
  35. Jirâkovâ, H., Huneau, F., Celle-Jeanton, H., Hrkal, Z., & Le Coustumer, P. (2011). Insights into palaeorecharge conditions for European deep aquifers. Hydrogeology Journal, 19, 1545–1562. doi: 10.1007/s10040-011-0765-7.CrossRefGoogle Scholar
  36. Jørgensen, L. F., & Stockmarr, J. (2009). Groundwater monitoring in Denmark: characteristics, perspectives and comparison with other countries. Hydrogeology Journal, 17, 827–842. doi: 10.1007/s10040-008-0398-7.CrossRefGoogle Scholar
  37. Kanduč, T., Grassa, F., McIntosh, J., Stibilj, V., Ulrich-Supovec, M., Supovec, I., & Jamnikar, S. (2014). A geochemical and stable isotope investigation of groundwater/surface-water interactions in the Velenje Basin, Slovenia. Hydrogeology Journal, 22, 971–984. doi: 10.1007/s10040-014-1103-7.CrossRefGoogle Scholar
  38. Kaya, E., Zarrouk, S. J., & O’Sullivan, M. J. (2011). Reinjection in geothermal fields: a review of worldwide experience. Renewable and Sustainable Energy Reviews, 15, 47–68. doi: 10.1016/j.rser.2010.07.032.CrossRefGoogle Scholar
  39. Kendall, C., & McDonnell, J. J. (2006). Isotope tracers in catchment hydrology. New York: Elsevier.Google Scholar
  40. Kharaka, Y. K., & Hanor, J. S. (2005). 5.16 deep fluids in the continents: I. Sedimentary basins. In J. I. Drever (Ed.), Surface and ground water, weathering, and soils (pp. 499–540). Kidlington: Elsevier.Google Scholar
  41. Kovács, L. Ó., & Varsányi, I. I. (2009). Origin, chemical and isotopic evolution of formation water in geopressured zones in the Pannonian Basin, Hungary. Chemical Geology, 264, 187–196. doi: 10.1016/j.chemgeo.2009.03.006.CrossRefGoogle Scholar
  42. Kovács, L. Ó., Varsányi, I. I., & Palcsu, L. (2011). Groundwater flow system as an archive of palaeotemperature: noble gas, radiocarbon, stable isotope and geochemical study in the Pannonian Basin, Hungary. Applied Geochemistry, 26, 91–104. doi: 10.1016/j.apgeochem.2010.11.006.CrossRefGoogle Scholar
  43. Kralj, P. (2004a). Chemical composition of low temperature (<20–40 °C) thermal waters in Slovenia. Environmental Geology, 46, 635–642. doi: 10.1007/s00254-004-1001-8.Google Scholar
  44. Kralj, P. (2004b). Trace elements in medium-temperature (40–80 °C) thermal waters from the Mura basin (North-Eastern Slovenia). Environmental Geology, 46, 622–629. doi: 10.1007/s00254-004-1000-9.Google Scholar
  45. Kralj, P., & Kralj, P. (2000). Thermal and mineral waters in north-eastern Slovenia. Environmental Geology, 39, 488–500. doi: 10.1007/s002540050455.CrossRefGoogle Scholar
  46. Kralj, P., & Kralj, P. (2012). Geothermal waters from composite clastic sedimentary reservoirs: geology, production, overexploitation, well cycling and leakage—a case study of the Mura basin (SW Pannonian basin). In J. Yang (Ed.), Geothermal energy, technology and geology (pp. 47–92). Nova Science Publishers: New York.Google Scholar
  47. Kun, W. (2010). Monitoring and resources evaluation of the geothermal fields in Tianjin. In: Proceedings World Geothermal Congress 2010 (7 p.). Bali, IGA.Google Scholar
  48. Lapanje, A. (2006). Origin and chemical composition of thermal and thermomineral waters (in Slovenian). Geologija, 49, 347–370. doi: 10.5474/geologija.2006.025.CrossRefGoogle Scholar
  49. Lopez, S., Hamm, V., Le Brun, M., Schaper, L., Boissier, F., et al. (2010). 40 years of Dogger aquifer management in Ile-de-France, Paris Basin, France. Geothermics, 39, 339–356. doi: 10.1016/j.geothermics.2010.09.005.CrossRefGoogle Scholar
  50. Mátyás, J. (1997). Stable isotopic mass balance in sandstone-shale couplets: an example from the Neogene Pannonian basin. Földtani Közlöny.Google Scholar
  51. Mezga, K., Urbanc, J., & Cerar, S. (2014). The isotope altitude effect reflected in groundwater: a case study from Slovenia. Isotopes in Environmental and Health Studies, 50, 33–51. doi: 10.1080/10256016.2013.826213.CrossRefGoogle Scholar
  52. Minissale, A., Borrini, D., Montegrossi, G., Orlando, A., Tassi, F., et al. (2008). The Tianjin geothermal field (north-eastern China): water chemistry and possible reservoir permeability reduction phenomena. Geothermics, 37, 400–428. doi: 10.1016/j.geothermics.2008.03.001.CrossRefGoogle Scholar
  53. Nádor, A., Lapanje, A., Tóth, G., Rman, N., Szőcs, T., et al. (2012). Transboundary geothermal resources of the Mura-Zala basin: joint thermal aquifer management of Slovenia and Hungary. Geologija, 55, 209–224. doi: 10.5474/geologija.2012.013.CrossRefGoogle Scholar
  54. Négrel, P., & Giraud, E. P. (2011). Isotopes in groundwater as indicators of climate change. Trends in Analytical Chemistry, 30, 1279–1290. doi: 10.1016/j.trac.2011.06.001.CrossRefGoogle Scholar
  55. Pezdič, J. (1991). Isotopes in thermo-mineral aquaeous systems, PhD thesis (in Slovenian). Ljubljana, University of Ljubljana.Google Scholar
  56. Pezdič, J., Dolenec, T., Pirc, S., & Žižek, D. (1995). Hydrogeochemical properties and activity of the fluids in the Pomurje region of the Pannonian sedimentary basin. Acta Geologica Hungarica, 39, 319–340.Google Scholar
  57. Prasanna, M. V., Chidambaram, S., Shahul Hameed, A., & Srinivasamoorthy, K. (2010). Study of evaluation of groundwater in Gadilam basin using hydrogeochemical and isotope data. Environmental Monitoring and Assessment, 168, 63–90. doi: 10.1007/s10661-009-1092-5.CrossRefGoogle Scholar
  58. Prosser, S. J., & Scrimgeour, C. M. (1995). High-precision determination of 2H/1H in H2 and H2O by continuous-flow isotope ratio mass spectrometry. Analytical Chemistry, 67, 1992–1997. doi: 10.1021/ac00109a014.CrossRefGoogle Scholar
  59. Re, V., Cissé Faye, S., Faye, A., Faye, S., Gaye, C. B., Sacchi, E., & Zuppi, G. M. (2011). Water quality decline in coastal aquifers under anthropic pressure: the case of a suburban area of Dakar (Senegal). Environmental Monitoring and Assessment, 172, 605–622. doi: 10.1007/s10661-010-1359-x.CrossRefGoogle Scholar
  60. Rman, N. (2014). Analysis of long-term thermal water abstraction and its impact on low-temperature intergranular geothermal aquifers in the Mura-Zala basin, NE Slovenia. Geothermics, 51, 214–227. doi: 10.1016/j.geothermics.2014.01.011.CrossRefGoogle Scholar
  61. Rman, N., Kumelj, Š., Tullner, T., Orosz, L., Palotás, K. (2011a). T-JAM borehole database. Ljubljana, Budapest, GeoZS, MAFI. Accessed 26 July 2015.
  62. Rman, N., Lapanje, A., & Prestor, J. (2011a). Water concession principles for geothermal aquifers in the Mura-Zala Basin, NE Slovenia. Water Resources Management, 25, 3277–3299. doi: 10.1007/s11269-011-9855-5.CrossRefGoogle Scholar
  63. Rman, N., Lapanje, A., & Rajver, D. (2012). Analysis of thermal water utilization in the northeastern Slovenia (in Slovenian). Geologija, 55, 225–242. doi: 10.5474/geologija.2012.014.CrossRefGoogle Scholar
  64. Rman, N., Gál, N., Marcin, D., Weilbold, J., Schubert, G., et al. (2015). Potentials of transboundary thermal water resources in the western part of the Pannonian basin. Geothermics, 55, 88–98. doi: 10.1016/j.geothermics.2015.01.013.CrossRefGoogle Scholar
  65. Rozanski, K., Araguás-Araguás, L., & Gonfiantini, R. (1992). Relation between long-term trends of oxygen-18 isotope composition of precipitation and climate. Science, 258, 981–985. doi: 10.1126/science.258.5084.981.CrossRefGoogle Scholar
  66. Simon, S. (2009). Characterization of groundwater and lake interaction in saline environment, at Kelemenszék Lake, Danube-Tisza Interfluve, Hungary, PhD thesis. Budapest, Eötvös Loránd University. Accessed 26 July 2015.
  67. Simonič, M., & Ozim, V. (2000). Purification of a contaminated thermal well at an oil drilling site. Environmental Toxicology, 14, 211–216. doi: 10.1002/(SICI)1522-7278(199905)14:2<211::AID-TOX1>3.0.CO;2-5.CrossRefGoogle Scholar
  68. Šram, D., Rman, N., Rižnar, I., & Lapanje, A. (2015). The three-dimensional regional geological model of the Mura-Zala Basin, northeastern Slovenia. Geologija, 58(2), 139–154. doi: 10.5474/geologija.2015.011.CrossRefGoogle Scholar
  69. Stefansson, V. (1997). Geothermal reinjection experience. Geothermics, 26, 99–139. doi: 10.1016/S0375-6505(96)00035-1.CrossRefGoogle Scholar
  70. Stewart, M. K. (1981). 18O and D enrichment by evaporation from sample containers. The International Journal of Applied Radiation and Isotopes, 32, 159–163. doi: 10.1016/0020-708X(81)90107-1.CrossRefGoogle Scholar
  71. Szanyi, J., & Kovács, B. (2010). Utilization of geothermal systems in South-East Hungary. Geothermics, 39, 357–364. doi: 10.1016/j.geothermics.2010.09.004.CrossRefGoogle Scholar
  72. Szőcs, T., Tóth, G., & Horvath, I. (2008). Using stable isotope data to characterise flow systems in the Pannonian Basin, Hungary. In J. C. Refsgaard (Ed.), Calibration and reliability in groundwater modelling: credibility of modelling (Vol. 320, pp. 131–136). Denmark: IAHS Publication.Google Scholar
  73. Szőcs, T., Rman, N., Süveges, M., Palcsu, L., Tóth, G., & Lapanje, A. (2013). The application of isotope and chemical analyses in managing transboundary groundwater resources. Applied Geochemistry Special Issue, 32, 95–107. doi: 10.1016/j.apgeochem.2012.10.006.CrossRefGoogle Scholar
  74. Tan, H., Zhang, Y., Zhang, W., Kong, N., Zhang, Q., & Huang, J. (2014). Understanding the circulation of geothermal waters in the Tibetan Plateau using oxygen and hydrogen stable isotopes. Applied Geochemistry, 51, 23–32. doi: 10.1016/j.apgeochem.2014.09.006.CrossRefGoogle Scholar
  75. Tóth, G., Rman, N., Rotár-Szalkai, Á., Kerékgyártó, T., Szőcs, T., Lapanje, A., Černák, R., Remsík, A., Schubert, G., & Nádor, A. (2016). Transboundary fresh and thermal groundwater flows in the west part of the Pannonian Basin. Renewable and Sustainable Energy Reviews, 57, 439–454. doi: 10.1016/j.rser.2015.12.021.CrossRefGoogle Scholar
  76. Varsányi, I. I., & Kovács, L. Ó. (2009). Origin, chemical and isotopic evolution of formation water in geopressured zones in the Pannonian Basin, Hungary. Chemical Geology, 264, 187–196. doi: 10.1016/j.chemgeo.2009.03.006.CrossRefGoogle Scholar
  77. Varsányi, I. I., Matray, J. M., & Kovács, L. Ó. (1997). Geochemistry of formation waters in the Pannonian Basin (southeast Hungary). Chemical Geology, 140, 89–106. doi: 10.1016/S0009-2541(97)00045-4.CrossRefGoogle Scholar
  78. Varsányi, I. I., Matray, J. M., & Kovács, L. Ó. (1999). Hydrogeochemistry in two adjacent areas in the Pannonian Basin (Southeast-Hungary). Chemical Geology, 156, 25–39. doi: 10.1016/S0009-2541(98)00178-8.CrossRefGoogle Scholar
  79. Vető, I., Futó, I., Horváth, I., & Szántó, Z. (2004). Late and deep fermentative methanogenesis as reflected in the H-C-O-S isotopy of the methane-water system in deep aquifers of the Pannonian Basin (SE Hungary). Organic Geochemistry, 35, 713–723. doi: 10.1016/j.orggeochem.2004.02.004.CrossRefGoogle Scholar
  80. Vreča, P., Bronić, I., Horvatinčić, N., & Barešić, J. (2006). Isotopic characteristics of precipitation in Slovenia and Croatia: comparison of continental and maritime stations. Journal of Hydrology, 330, 457–469. doi: 10.1016/j.jhydrol.2006.04.005.CrossRefGoogle Scholar
  81. Zhang, S., Tang, S., Li, Z., Guo, Q., & Pan, Z. (2015). Stable isotope characteristics of CBM co-produced water and implications for CBM development: the example of the Shizhuangnan block in the southern Qinshui Basin, China. Journal of Natural Gas Science and Engineering, 27, 1400–1411. doi: 10.1016/j.jngse.2015.10.006.CrossRefGoogle Scholar
  82. Žlebnik, L. (1978). Tertiary aquifers in the Slovenske gorice and Goričko hills (in Slovenian). Geologija, 21, 311–324.Google Scholar
  83. Zmazek, B., Italiano, F., Zivcic, M., Vaupotic, J., Kobal, I., & Martinelli, G. (2002). Geochemical monitoring of thermal waters in Slovenia: relationships to seismic activity. Applied Radiation and Isotopes, 57, 919–930. doi: 10.1016/S0969-8043(02)00200-2.CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Geological Survey of SloveniaLjubljanaSlovenia

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