heavy water

["Frame, Paul" <FrameP@ORAU.GOV>]

Since the subject appears to be of interest, at least to some, the following

is something I put together for the HPS Newsletter a few years back  - the

true story of the first tracer study using D2O:



Springtime  1913.  Hevesy was "indulging in a cup of tea at the Manchester

Physics Laboratory" with the immortal Henry J.G. Moseley. In one of those

moments of idle speculation the spring season seems to bring upon us, Hevesy

expressed a desire to "determine the fate of the individual water molecules

contained in the cup of tea consumed."  Moseley was not inclined to engage

in such flights of fancy and, as Hevesy commented,  "even a man of the

vision and outlook of ... H.J.G. Moseley considered this hope to be a highly

utopian one"(Hevesy 1962).  But Moseley was wrong, Hevesy would indeed learn

the fate of those water molecules.  Moseley never did  -   he was shot and

killed by a Turkish sniper in the Battle of Suvla Bay in 1915.     

	The means to discover the mysterious fate of consumed tea came in

1933 when Harold Urey provided Hevesy with several liters of  0.6% deuterium

oxide (a.k.a. heavy water). Whether or not Hevesy made tea from it is not

recorded, but he and his new drinking buddy, E. Hofer, consumed the stuff in

150, 250, and for the sake of precision, 2000 ml aliquots. After "55 samples

of urine and other excreta were investigated and more than 1000 distillation

operations carried out" (Hevesy and Hofer 1934), simple gravimetric

measurements revealed that half of the body's water  turned over every 9

days  - a measurement that represents the first application of isotopic

tracers in the clinical sciences. And in the first use of isotopic dilution

in the biological sciences, Hevesy and Hofer estimated the body's water

content at  43 liters. Although not given to sentimentality, Hevesy fondly

recalled the springtime cup of tea with his late friend Henry Moseley in the

opening sentence of the paper in which he and Hofer reported their findings.



Paul Frame

Professional Training Programs

ORAU

http://www.orau.com/ptp/ptp.htm

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