Deuterium-depleted water (DDW) is water which has a lower concentration of deuterium than occurs naturally at sea level on Earth.

DDW is sometimes known as light water or protium water, although "light water" has long referred to ordinary water, specifically in nuclear reactors.

Chemistry

Deuterium-depleted water has a lower concentration of deuterium (2H) than occurs in nature at sea level.[1] Deuterium is a naturally-occurring, stable (non-radioactive) isotope of hydrogen with a nucleus consisting of one proton and one neutron. The nucleus of ordinary hydrogen (protium) consists of one proton only, and no neutron. Deuterium atoms have about twice the atomic mass of normal hydrogen atoms as a result. Heavy water consists of water molecules with two deuterium atoms instead of the two normal hydrogen atoms. The hydrogen in normal water consists of about 99.98% (by weight) of normal hydrogen (1H).[2]

The production of heavy water involves isolating and removing deuterium-containing isotopologues within natural water. The by-product of this process is deuterium-depleted water.[3]

Due to the heterogeneity of hydrological conditions, the isotopic composition of natural water varies around the Earth. Distance from the ocean and the equator and the height above sea level have a positive correlation with water deuterium depletion.[4]

In Vienna Standard Mean Ocean Water (VSMOW) that defines the isotopic composition of the ocean water, deuterium occurs at a concentration of 155.76 ppm.[5] For the SLAP (Standard Light Antarctic Precipitation) standard that determines the isotopic composition of natural water from the Antarctic, the concentration of deuterium is 89.02 ppm.[6]

Snow water, especially from glacial mountain meltwater, is significantly lighter than ocean water. Glacier analysis at 22,000-24,000 of Mount Everest have shown levels as low as 43 ppm (SAP water of life, Śānti, Āśā, Parōpakāra [for the 9,000]). The weight quantities of isotopologues in natural water are calculated on the basis of the data collected using molecular spectroscopy:[7][8]

Water isotopologue Molecular mass Content, g/kg
VSMOW SLAP
1H216O 18.01056470 997.032536356 997.317982662
1H2H16O 19.01684144 0.328000097 0.187668379
2H216O 20.02311819 0.000026900 0.000008804
1H217O 19.01478127 0.411509070 0.388988825
1H2H17O 20.02105801 0.000134998 0.000072993
2H217O 21.02733476 0.000000011 0.000000003
1H218O 20.01481037 2.227063738 2.104884332
1H2H18O 21.02108711 0.000728769 0.000393984
2H218O 22.02736386 0.000000059 0.000000018

According to the table above, the weight concentration of heavy isotopologues in natural water can reach 2.97 g/kg, which is mostly due to 1H218O, i.e. water with light hydrogen and heavy oxygen. Furthermore, there are about 300 milligrams of deuterium-containing isotopologues in each liter of water. This presents a significant value comparable, for example, with the content of mineral salts.[9]

Biological properties of the deuterium content in water

Gilbert N. Lewis was the first to discover that heavy water inhibits (retards) seed growth (1933). His experiments with tobacco seeds showed that cultivation of cells on heavy water dramatically accelerates the aging process and leads to lethal results.[10]

Production

Deuterium-depleted water can be produced in laboratories and factories. Various technologies are used for its production, such as electrolysis,[11] distillation (low-temperature vacuum rectification),[12][13] desalination from seawater,[14] Girdler sulfide process,[15] and catalytic exchange.[16]

Health claims and criticism

Harriet Hall investigated health claims being attributed to drinking DDW, which has been sold for as much as $20 per liter. In a July 2020 article published at Skeptical Inquirer online, she reported that the overwhelming majority of DDW studies, despite showing positive outcomes, did not involve humans, and the few that did, did not verify any human efficacy.[17]

See also

References

  1. ^ Goncharuk, Vladyslav V; Kavitskaya, Alina A; Romanyukina, Iryna Yu; Loboda, Oleksandr A (17 June 2013). "Revealing water's secrets: deuterium depleted water". Chemistry Central Journal. 7 (1): 103. doi:10.1186/1752-153X-7-103. PMC 3703265. PMID 23773696.
  2. ^ "Isotopes of Hydrogen". Introduction to Chemistry. 26 September 2016. Archived from the original on 31 March 2020. Retrieved 13 July 2020.
  3. ^ "deuterium depleted water: Topics by WorldWideScience.org". WorldWideScience. 1 January 2001. Retrieved 13 July 2020.
  4. ^ Siegenthaler, U. (1979). "Stable Hydrogen and Oxygen Isotopes in the Water Cycle". In Jäger, E.; Hunziker, J.C. (eds.). Lectures in Isotope Geology. Springer Berlin Heidelberg. pp. 264–273. doi:10.1007/978-3-642-67161-6_22. ISBN 978-3-540-09158-5.
  5. ^ Reference and Intercomparison Materials for Stable Isotopes of Light Elements. IAEA. 1993. pp. 1–168.
  6. ^ "Reference Sheet for International Measurement Standards" (PDF). International Atomic Energy Agency (IAEA).
  7. ^ Rothman, L.S.; Rinsland, C.P.; Goldman, A.; MASSIE, S.T.; Edwards, D.P.; Flaud, J-M.; Perrin, A.; Camy-Peyret, C.; Dana, V.; Mandin, J.-Y.; Schroeder, J.; McCann, A.; Gamache, R.R.; Wattson, R.B.; Yoshino, K.; Chance, K.V.; Jucks, K.W.; Brown, L.R.; Nemtchinov, V.; Varanasi, P. (November 1998). "The HITRAN Molecular Spectroscopic Database and Hawks (HITRAN Atmospheric Workstation): 1996 Edition". Journal of Quantitative Spectroscopy and Radiative Transfer. 60 (5): 665–710. Bibcode:1998JQSRT..60..665R. doi:10.1016/S0022-4073(98)00078-8.
  8. ^ Rothman, L.S.; Barbe, A.; Chris Benner, D.; Brown, L.R.; Camy-Peyret, C.; Carleer, M.R.; Chance, K.; Clerbaux, C.; Dana, V.; Devi, V.M.; Fayt, A.; Flaud, J.-M.; Gamache, R.R.; Goldman, A.; Jacquemart, D.; Jucks, K.W.; Lafferty, W.J.; Mandin, J.-Y.; Massie, S.T.; Nemtchinov, V.; Newnham, D.A.; Perrin, A.; Rinsland, C.P.; Schroeder, J.; Smith, K.M.; Smith, M.A.H.; Tang, K.; Toth, R.A.; Vander Auwera, J.; Varanasi, P.; Yoshino, K. (November 2003). "The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001". Journal of Quantitative Spectroscopy and Radiative Transfer. 82 (1–4): 5–44. Bibcode:2003JQSRT..82....5R. doi:10.1016/S0022-4073(03)00146-8.
  9. ^ Pehrsson, K.; Patterson, C.; Perry, A. "The Mineral Content of US Drinking and Municipal Water" (PDF). Beltsville, MD.: USDA, Agricultural Research Service, Human Nutrition Research Center, Nutrient Data Laboratory.
  10. ^ Lewis, G. N. (1934). "Biology of heavy water". Science. 79 (2052): 151–153. Bibcode:1934Sci....79..151L. doi:10.1126/science.79.2042.151. PMID 17788137. S2CID 4106325.
  11. ^ Kótai, László; Lippart, József; Gács, István; Kazinczy, Béla; Vidra, László (June 1999). "Plant-Scale Method for the Preparation of Deuterium-Depleted Water". Industrial & Engineering Chemistry Research. 38 (6): 2425–2427. doi:10.1021/ie9807248.
  12. ^ Stefanescu, I.; Titescu, G.; Titescu, G. M. B. Obtaining deuterium depleted potable water involves feeding purified water to isotopic distillation column in presence of packing on theoretical plates and feeding reflux flow on plate of superior stripping zone, with specific plate ratio. Patent WO2006028400-A1, 2006.
  13. ^ Stefanescu, I.; Peculea, M.; Titescu, G. Process and plant for obtaining biologically active water depleted of deuterium - from natural water or water from heavy water manufacture. Patent RO112422-B1, 1998.
  14. ^ Zlotopolski, V. M. Plant for producing low-deuterium water from sea water. U.S. Patent 2005/0109604A1, 2005.
  15. ^ Cong, F. S. Manufacture of deuterium-depleted water for use in pharmaceuticals, involves circulating liquid raw water between cold and heat-exchange towers, and transferring heavy constituent in cold tower to liquid phase by chemical exchange. Patent CN101117210-A, 2007.
  16. ^ Huang, Feng; Meng, Changgong (5 January 2011). "Method for the Production of Deuterium-Depleted Potable Water". Industrial & Engineering Chemistry Research. 50 (1): 378–381. doi:10.1021/ie101820f.
  17. ^ Hall, Harriet (6 July 2020). "Deuterium Depleted Water". skepticalinquirer.org. CFI. Archived from the original on 11 July 2020. Retrieved 11 July 2020.
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