Reprinted from Science, May 27, 1966, Vol. 152, No. 3726, pages 1261-1262
10%
from 32 subjects resident in the fol-
lowing three general areas of the Yukon
and Northwest Territories: Area No.
1, the town of Yellowknife: Area No.
2. rural inland districts in the Mackenzie River and Southern Yukon region; and Area No. 3, the northwest
shores of Hudson Bay. The subjects
can also be classified in the following
three groups on the basis of dietary
habit: (i) reindeer or caribou meat
consumed several times a week, (ii)
—
*
3
s
0107}
and (iii) diet not described as “high
protein” or not including reindeer or
caribou meat (that is, “normal”). No
dietary record was obtained for the
English series of ten samples and, because the samples were collected unselectively and in the sequence in which
they were delivered in a general hospital, they can be presumed to be rep-
resentative of the area where they were
obtained.
Determinations of the concentration
ee
N
a
—
*
m 100
°
3
Onn
either reindeer or caribou meat con-
sumed about once a week or a diet
described generally as “high protein,”
407967
{
109
io
Po2!?
(pc /100q}
Fig. 1. Relationship between Po” and Cs™
concentrations measured in human placentas.
for bone has been derived from the
concentration ratio, bone/liver, found
in another set of measurements of
autopsy material, which was carried
out on tissue from hospitalized subjects
with terminal illness (2).
The ratios given in the third column
of Table 2 should provide a means for
of Po7!° in these samples were carried
out by a method previously described
(7), and results are given in Table 1.
estimating the Po!® concentration in
the corresponding tissues of the subjects of Table 1, and in particular the
samples are comparable to those for the
English series, while the value for the
caribou-reindeer eaters are generally
higher than the “normal” mean value
useful to bear in mind that a Po!
Values for the Canadian “normal diet”
“meat eaters.” In this connection it is
concentration of | pe/100 g, uniformly
distributed, gives rise to a tissue dose
rate of about 1 mrad/yr.
by factors of up to 80. This is about
Polonium-210 Content of Human
Tissues in Relation to Dietary Habit
Abstract. Concentrations of polonium-210, a natural fallout nuclide, in
human placentas collected in northern
Canada ranged up te 27.8 picocuries
per 100 grams, or 80 times the average
United Kingdom value. High levels are
related to the inclusion of reindeer or
caribou meat in the diet, and a correlation exists between the concentrations
of polonium-210 and cesium-137 in the
placentas.
Attempts to follow up the suggestion
(1) that there may be relatively high
levels of Po*!° in tissues of people dependent for food on meat of animals,
such as reindeer and caribou, that graze
on lichens have hitherto been prevented
by difficulties in obtaining suitable
samples of tissue. I now report on measurements made on a series of human
placentas obtained from residents of
northern Canada, as compared with
a series from London, United Kingdom. The Canadian series was obtained
the same range of variation found in
earlier measurements on samples of
Eskimo bones (where, however. no information on diet was available) (/).
The results (Table 1) also indicate a
dependence of Po?!” concentration on
residence locality, as such, among subjects within a given diet classification.
However, this may simply reflect the
inadequacy of the information available
to us concerning detailed dietary habits
of subjects in the areas concerned. The
values of the activity ratio of Pb7'9/
Po"! (shown in parentheses) that have
been measured for some of the samples
Table 1, Polonium-210 concentration, in picocuries per 100 @ (wet wt.) in human placenta. Activity ratios, Pb*'/Po™°, are shown
tn parentheses.
Yellowknife,
NLW.T.
2.41 (0.25)
2.41
son of the English placenta series with
a previous set of measurements of Po“!9
in autopsy samples from accident cases
occurring in the same area as that from
which the placenta samples were drawn
(7). This comparison is made in Table
2. Unfortunately bone was not included
in this series of measurements; a value
Hudson
Bay coast
London,
U.K.
Much reindeer and caribou
1.54
4.3
$.28
(0,16)
3.41
5.4
9.3
12.2
14,1
22.8
11.4 + 6.2
Some reindeer and caribou, or “high protein”
0.35
G.09
1.07 (0.64)
1.48 (0.75)
3.09 (0.27)
show, in every case, that Po=!? is in
excess of equilibrium with Pb?!°.
Estimation of the Po=™ concentrations in other body organs of the Canadian residents can be made by compart-
Inland,
tural
3.2
5.4
9.6
10.8
11.5
12.2
27.8
0.35
1.44
115473
“Normal” (no reindeer or caribou)
0.08
0.18
0.19
0.24
0.30
0.31
0.36
0.40
0.45
0.58
0.92
0.36 + 0.22
“ay,
0.14
0.23
ay 90.26
a
0.27
. ay
ah
0.28
0.29
0.37
0.39
0.50
0.52
0.334 0.11