The vulnerability of groundwater to contamination is closely related to its age. Groundwaters that infiltrated prior to the Holocene have been documented in many aquifers and are widely assumed to be unaffected by modern contamination. However, the global prevalence of these ‘fossil’ groundwaters and their vulnerability to modern-era pollutants remain unclear. Here we analyse groundwater carbon isotope data (12C, 13C, 14C) from 6,455 wells around the globe. We show that fossil groundwaters comprise a large share (42–85%) of total aquifer storage in the upper 1 km of the crust, and the majority of waters pumped from wells deeper than 250 m. However, half of the wells in our study that are dominated by fossil groundwater also contain detectable levels of tritium, indicating the presence of much younger, decadal-age waters and suggesting that contemporary contaminants may be able to reach deep wells that tap fossil aquifers. We conclude that water quality risk should be considered along with sustainable use when managing fossil groundwater resources.
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Gleeson, T., Befus, K. M., Jasechko, S., Luijendijk, E. & Cardenas, M. B. The global volume and distribution of modern groundwater. Nat. Geosci. 9, 161–168 (2016).
Messager, M. L., Lehner, B., Grill, G., Nedeva, I. & Schmitt, O. Estimating the volume and age of water stored in global lakes using a geo-statistical approach. Nat. Commun. 7, 13603 (2016).
Siebert, S. et al. Groundwater use for irrigation—a global inventory. Hydrol. Earth Syst. Sci. 14, 1863–1880 (2010).
Fan, Y., Li, H. & Miguez-Macho, G. Global patterns of groundwater table depth. Science 339, 940–943 (2013).
Chen, Z., Nie, Z., Zhang, Z., Qi, J. & Nan, Y. Isotopes and sustainability of ground water resources, North China Plain. Groundwater 43, 485–493 (2005).
Yamada, C. First Report on Shared Natural Resources (United Nations International Law Commission, A/CN.4/533 + Add.1, 2003); http://www.legal.un.org/ilc/documentation/english/a_cn4_533.pdf
Buser, H. R. Atrazine and other s-triazine herbicides in lakes and in rain in Switzerland. Environ. Sci. Technol. 24, 1049–1058 (1990).
Burgess, W. G. et al. Vulnerability of deep groundwater in the Bengal Aquifer System to contamination by arsenic. Nat. Geosci. 3, 83–87 (2010).
Taylor, R. G. et al. Ground water and climate change. Nat. Clim. Change 3, 322–329 (2013).
Thatcher, L., Rubin, M. & Brown, G. F. Dating desert groundwater. Science 134, 105–106 (1961).
Edmunds, W. M. & Wright, E. P. Groundwater recharge and palaeoclimate in the Sirte and Kufra basins, Libya. J. Hydrol. 40, 215–241 (1979).
Phillips, F. M., Peeters, L. A., Tansey, M. K. & Davis, S. N. Paleoclimatic inferences from an isotopic investigation of groundwater in the central San Juan Basin, New Mexico. Quat. Res. 26, 179–193 (1986).
Weyhenmeyer, C. E. et al. Cool glacial temperatures and changes in moisture source recorded in Oman groundwaters. Science 287, 842–845 (2000).
Plummer, N. L. & Sprinkle, C. L. Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA. Hydrogeol. J. 9, 127–150 (2001).
Vengosh, A., Gill, J., Davisson, M. L. & Hudson, G. B. A multi-isotope (B, Sr, O, H, and C) and age dating (3H–3He, and 14C) study of groundwater from Salinas Valley, California: hydrochemistry, dynamics, and contamination processes. Wat. Resour. Res. 38, 1008 (2002).
Brown, K. B., McIntosh, J. C., Baker, V. R. & Gosch, D. Isotopically-depleted late Pleistocene groundwater in Columbia River Basalt aquifers: evidence for recharge of glacial Lake Missoula floodwaters? Geophys. Res. Lett. 37, L21402 (2010).
Morrissey, S. K., Clark, J. F., Bennett, M., Richardson, E. & Stute, M. Groundwater reorganization in the Floridan aquifer following Holocene sea-level rise. Nat. Geosci. 3, 683–687 (2010).
Cartwright, I. & Weaver, T. R. Hydrogeochemistry of the Goulburn Valley region of the Murray Basin, Australia: implications for flow paths and resource vulnerability. Hydrogeol. J. 13, 752–770 (2005).
Vogel, J. C. Isotope Hydrology 225–239 (International Atomic Energy Agency STI/PUB/255, 1970).
Jasechko, S. Partitioning young and old groundwater with geochemical tracers. Chem. Geol. 427, 35–42 (2016).
Weissmann, G. S., Zhang, Y., LaBolle, E. M. & Fogg, G. E. Dispersion of groundwater age in an alluvial aquifer system. Wat. Resour. Res. 38, 1198 (2002).
Bethke, C. M. & andJohnson, T. M. Groundwater age and groundwater age dating. Annu. Rev. Earth Planet. Sci. 36, 121–152 (2008).
Torgersen, T. et al. Isotope Methods for Dating Old Groundwater (International Atomic Energy Agency, 2013).
Jasechko, S. & Taylor, R. G. Intensive rainfall recharges tropical groundwaters. Environ. Res. Lett. 10, 124015 (2015).
Jasechko, S., Kirchner, J. W., Welker, J. M. & McDonnell, J. J. Substantial proportion of global streamflow less than three months old. Nat. Geosci. 9, 126–129 (2016).
Aggarwal, P. K., Araguas-Araguas, L., Choudhry, M., van Duren, M. & Froehlich, K. Lower groundwater 14C age by atmospheric CO2 uptake during sampling and analysis. Groundwater 52, 20–24 (2014).
Wada, Y., Wisser, D. & Bierkens, M. F. P. Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources. Earth Syst. Dyn. 5, 15–40 (2014).
Famiglietti, J. S. The global groundwater crisis. Nat. Clim. Change 4, 945–948 (2014).
Bauch, N. J., Musgrove, M., Mahler, B. J. & Paschke, S. S. The quality of our Nation’s waters—Water Quality in the Denver Basin Aquifer System, Colorado, 2003-05 U.S. Geological Survey Circular 1357 (2014).
Theis, C. V. The source of water derived from wells. Civil Eng. 10, 277–280 (1940).
Russo, T. A. & Lall, U. Depletion and response of deep groundwater to climate-induced pumping variability. Nat. Geosci. 10, 105–108 (2017).
Toth, J. A theoretical analysis of groundwater flow in small drainage basins. J. Geophys. Res. 68, 4795–4812 (1963).
Jiang, X. W., Wan, L., Cardenas, M. B., Ge, S. & Wang, X. S. Simultaneous rejuvenation and aging of groundwater in basins due to depth-decaying hydraulic conductivity and porosity. Geophys. Res. Lett. 37, L05403 (2010).
Zinn, B. A. & Konikow, L. F. Effects of intraborehole flow on groundwater age distribution. Hydrogeol. J. 15, 633–643 (2007).
Ferguson, G. A., Betcher, R. N. & Grasby, S. E. Hydrogeology of the Winnipeg formation in Manitoba, Canada. Hydrogeol. J. 15, 573–587 (2007).
Lin, L. H. et al. Long-term sustainability of a high-energy, low-diversity crustal biome. Science 314, 479–482 (2006).
Holland, G. et al. Deep fracture fluids isolated in the crust since the Precambrian. Nature 497, 367–360 (2013).
Burow, K. R., Nolan, B. T., Rupert, M. G. & Dubrovsky, N. M. Nitrate in groundwater of the United States, 1991–2003. Environ. Sci. Technol. 44, 4988–4997 (2010).
Graham, J. P. & Polizzotto, M. L. Pit latrines and their impacts on groundwater quality: a systematic review. Environ. Health Perspect. 121, 521–530 (2013).
Sorensen, J. P. R. et al. Emerging contaminants in urban groundwater sources in Africa. Water Res. 72, 51–63 (2015).
MacDonald, A. M. et al. Groundwater quality and depletion in the Indo-Gangetic Basin mapped from in situ observations. Nat. Geosci. 9, 762–766 (2016).
Reimer, P. J. et al. IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55, 1869–1887 (2013).
Hua, Q. & Barbetti, M. Review of tropospheric bomb 14C data for carbon cycle modeling and age calibration purposes. Radiocarbon 46, 1273–1298 (2004).
Jasechko, S. Late-Pleistocene precipitation δ18O interpolated across the global landmass. Geochem. Geophys. Geosyst. 17, 3274–3288 (2016).
New, M., Lister, D., Hulme, M. & Makin, I. A high-resolution data set of surface climate over global land areas. Clim. Res. 21, 1–25 (2002).
S.J. was supported by an NSERC Discovery Grant. R.G.T. acknowledges support of the NERC-ESRC-DFID UPGro grant NE/M008932/1.
The authors declare no competing financial interests.
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Jasechko, S., Perrone, D., Befus, K. et al. Global aquifers dominated by fossil groundwaters but wells vulnerable to modern contamination. Nature Geosci 10, 425–429 (2017). https://doi.org/10.1038/ngeo2943
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