- 39 -
Positive counts were obtained for 14 of 21 persons
measured.
These counts suggested chest burdens ranging
from 3 to about 10 nCi.
However,
in no case did the
estimated chest burden exceed the MDA at the 95% con-
fidence level.
Seven of the 14 subjects with positive
chest counts had estimated chest burdens of 7 nCi or
greater and may be considered (at the 68% level of
confidence) to have statistically significant chest
burdens of from 7 to 10 nci.68
Since the plutonium is still in the lung cavity, 27 years
post-exposure, it is correct to assume that it was initially
in the insoluble form and hence pertinent here.
69
At the time
of this measurement, however, most of the material would be
expected to be in the lymph nodes.
Nevertheless, we could
estimate the initial particle burden in these subjects from
these data if we knew the initial particle size at the time
of contamination.
This particle size data is unavailable.
The nature of the contaminating events Sugcest that the
=
particle size might have been somewhat larger than those that
result from plutonium fires where most of the respirable
activity resides on particles in the size range of 0.1 u to
0.5 u in diameter. 70 Much of the contamination of the
69/
ICKP Publication
70/
Mann, J.R.
Op.
19,
cit., Dp.
474.
The Metabolism of Compounds of
Plutonium and Other Actnides, Pergamon Press, New York,
and A.R. Kirchner, Op.
cit., p.
880.
127
rey
Hemplemann, L.H.,
ty
68/