RK. L. BLANCHARD and J. B. MOORE
133
Table 5, A comparison of the “1°Pb content in old and recent caribou bones
Latitude
Concentration in recent (1965-1966)
caribou bones ( pCi 2p b/ajy
Concentrauion in pre-1951 caribou bones
from Table + ( pCi 29Pb/e}
<60°N
Range: 2.1-5.6 (1-1)
2.1 (fawn)
60°-65°N
Range: 2.1-7.5 (26)
5.4
~63°N
Mean:
3.1
-+ Oot
Mean: 4.5 + O.F
Range: 4.9-13.1 (15)
Mean:
15.4. 8.1
7.0 - 0.6
1.5 {(fawn)
\
Note: (a) The numberof caribou are given in parentheses
(b) The uncertainties are the standard deviations of the mean.
‘The next step in the arctic food chain is
caribou, which should also reflect higher levels
of *!°Pb after 1951 if nuclear testing contributed
substantially to the #®Pb levels in the aretic
environment. ‘UVhe *!°Pb results for the pre-1951
caribou bone samples given in ‘Table 4 are
compared in ‘Table 5 to adult caribou bone
samples which were collected during 19651966.Due to a possible increase in the 74°Pb
bone concentration with increasing latitude,’
the results in Table 5 are arranged in three
groups according to latitude. Except for sample
OC-05, a fawn, the results of the pre-1951
samples are within the range of values reported
for the recent samples.
As it has been reported that the *"Pb skeletal
burden of fawns is only about one-half that
found in the skeleton of the adult,{the two
samples from fawns, OC-04 and OC-05, are
undoubtedly low relative to adult caribou from
the same areas. As in the case for lichen samples,
there does not appear to be any substantial
increase in the #°Pb skeletal burden of caribou
following the advent of nuclear testing in the
arctic. Consequently, it scems unlikely that
arctic testing of nuclear weapons has had any
significant effect on the amountof #!°Pb in the
arctic ecosystem.
SUMMARY
Although there were relatively few tissue
samples available for study, the results indicate
that caribou or reindeer meat is the principal
source of 219Po for Alaskan residents, and that, in
general, the intake of ?Pb and #!°Po by inhalation is about the same as in the conterminous
United States. In addition, it was illustrated in
the case of these subjects that consumers of
caribou meat may ingest large quantities of
“10Po unsupported by its parent, 7Pb. ‘This
produces high “Po bedy burdens only as long as
the subject continues to eat caribou or remdeer
meat, and when the meat is climinated fromthe
dict the 2!°Po will be excreted within a relatively
short period and the body burden will approach
that of an unexposed person.
Phe Pb concentrations in lichen and
caribou bone samples collected belore 1951 were
comparable to concentrations in similar samples
recently collected. “Whe data tend to discount
the iinportance of nucleartesting in the arctic as
a significant source of 24°Pb.
Acknowledgement—TVhe authors thank Perer JArLow,
Alaskan Native Mcedicul Center, Anchorage and
Db. J. Werner, Alaskan Native Hospital, Kotzcbue,
for supplying the tissue samples; Mason Hate,
Smithsonian Institution, Washington, D.C., for the
pre-1951 lichen samples; P. M. YouncMman, National
Museum of Canada, Ottawa, for the pre-1951
caribou samples; and B. Kaun, ofthis laboratory, for
helpful suggestions during the preparation of this
paper.
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