Cosmogenic 22Na as an index of the residence time of water in freshwater basins: a review.
The goal of this review is to draw attention to an opportunity for the use of cosmogenic (22)Na for dating young surface and underground waters. After 1961 when a significant quantity of (22)Na was released into the environment as a result of nuclear weapon tests, its concentrations in river waters were greatly increased, and a return to natural (cosmogenic) levels took until the mid-1980s. The studies made during this non-steady-state period showed that the one-box model for freshwater basin correctly describes the experimental data. For the 19 studied basins of Russia, the Baltic States and Japan, a calculation based on this model gave values for the mean residence time of water in the range from 4 to 23 years. Now, only cosmogenic (22)Na is in the environment, and it is the single cosmogenic radionuclide at present, which can serve as a steady-state tracer for dating young waters (up to some decades).
Fleishman
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DG
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Torez pr. 44, St. Petersburg, Russia. davidfleyshman@yahoo.com
D005618:Fresh Water / Q000737:chemistry*; D008962:Models, Theoretical; D012979:Sodium Radioisotopes / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
D012979:Sodium Radioisotopes; D014875:Water Pollutants, Radioactive