Table 7. Comparative concentrations of Po?!®
in tissue of United Kingdom residents.
Tissue
Placenta
Liver
Po?" concn.
(pc/100 g)
Concn. ratio
tissue/plancenta
0.33
1.69
5.1
Kidney
1.72
5.2
Lung
0.54
1.6
Testis
Bone
0.39
2.9
1.2
8.8
In order to investigate the possibility
of a correlation between natural Po?!
and artificial Cs'*7 levels in human tissues,
y-Spectrometric
measurements
have been made of the Cs!** contents
of some of the placentas in the Cana-:
dian series. The results (Fig. 1) yield
a correlation coefficient of 0.93, significant at the O.1l-percent level, for
placental concentrations of the two nu-
clides and thus provide new evidence
for an origin and route of uptake of
the polonium isotope that are similar
to those of Cs!" The explanation of
this finding seems to lie in the natural
oon
atmospheric content of Rn?*?,
whose
decay results ultimately in production
of Po7!® (Cs!%" is also produced in the
atmosphere by radioactivity decay of
a rare gas, the fission product Xe!*7),
and in the predominant importance of
a food chain involving animals dependent for grazing on large areas of
slow-growing vegetation that is known
to accumulate both nuclides effectively,
following their
atmosphere.
deposition
from
the
C. R. Hite
Institute of Cancer Research,
Belmont, Surrey, United Kingdom
References and Notes
1. C. R. Hill, Nature 208, 423-28, (1965).
2.
R. ¥. Gsborne, W. V. Mayneord,
in
The
Natural Radiation
Environment,
J.
A.
S. Adams and W. M. Lowder, Eds. (Univ. of
Chicago Press, Chicago, 1964), p. 395.
3. I thank the staffs of the various Canadian
hospitals and St. Helier Hospital, Carshalton,
for providing the samples of placenta, and
P. M. Bird of the Canadian Department of
National Health and Welfare for organizing
the supply of specimens from Canada, The
Cs" measurements were made by R. Elrick
in our department.
17 January 1966
a