2100p], AND 2!0Po IN TISSUES OF SOME ALASKAN RESIDENTS
126
earth's surface primarily in rainfall and are
continually accumulated by the slow growing,
210Po deposited on the disc was measured in a
that a major fraction of the "Pb deposited in
recent years was produced in’ atmospheric
time of death.
long jiving arctic lichen. During this time,
“Po eraws inte near racdinactive equilibrium
with the "Pb. It has been sugeested, however,
nuclear detonations by the reaction *°8Pb(2n,7)
210} (14a)
‘The purpose of this study was to investigate
the increased tissue levels of 7!9Pb and #!°Po
associated with the consumption of caribou
meat. In addition, to ascertain the significance
of atmospheric nuclear detonations as a source
‘of 29Ph in the arctic, the concentration of 2190p},
in recently collected lichen and caribou bone
was compared with the concentration in similar
samples collected before L951. Radium-226 was
also measured in these older samples so that the
29P1) concentrations could be corrected for
ingrowth.
EXPERIMENTAL
The analytical proceedure employed for the
determination of ?°Ph and 7!"Po lias been described previously.4#!® “The samples were wet
ashed in nitric acid and 72°% perchloric acid
and the 2!©Po was deposited on a 2-in. silver
disc from a 0.5 V EEG] solution containing 200
me of ascorbie acid at 84°C. The 4°Pb present
was calculated from the 7!9Po ingrowth, which
was measured by repeating the *!’Po deposition
on another silver dise 3 & months after the
initial deposition.
‘The alpha activity of the
low-background (0,5-0.8 counts/hr) ZnS(Ag)
scintillation counter. The initial ?!?Po values
obtained were corrected for decay and ingrowth
from the 2°Pb to obtain the concentration at the
Any muscle attached to the bone was removed and the bones were fat extracted in
anhydrous benzene. Defatting the bones was
perforined in order to give a more reproducible
bone sample weight,"” and it was determined
that neither 2!°Pb nor 2!°Po was removed during
the extraction. The average ratio of defat
weight/fresh weight was 0.46 + 0.08 (S.D.) for
30 rib sainples.
The “8Ra content was measured by the
radon emanation method."!81
In each case,
the 8Ra content was measured in the same
sample used for the 7!°Pb analysis.
RESULTS AND DISCUSSION
Thuaman ftssies
In Table | are listed the data for the Alaskan
subjects from which tissue samples were obtained for analysis. The subjects are listed in
the order of increasing caribou consumption,
and the table includes the age, sex, residence and
a bricf statement on the frequency with which
caribou was eaten. Although it would be more
desirable to have knowledge of exact quantities
of caribou or reindeer consumed, such data was
not available.
Listed in Table 2 are the concentrations of
210Po and #°Pb measured in the various tissues.
Table 1. Human sample data
Subject
number
l
2
3
4
Age
6
}
15
410
MI
EF
78
5
65
6
7
25
55
8
Sex
77
daskan
residence
Planum
Caribou in diet
None
MM
Anchorage
Point Barrow
and .Anchorage
Eagle
None
Ate caribou meat regularly at Barrow, but hadlived in
Anchoragethe last three years where she ate none
‘Ate caribou meat occasionally
F
M
(near Bethel)
Anchorage
Kivalina
Ate caribou meat once or twice a month
Caribou meat was main diet in winter—fish in summer
NI
M
Akiak
Royuk
A few times a year
A steady diet of rerndeer meat, but ate none during
terminal illness of 3 months