year period.The standard deviation was in general 30% of the mean value for all ages
and sex subgroup distributions.
Thie lees pronounced variation may be due tv
.
:
0
the fact that $525 measurements took place over @ 3 year interval while 9 Sr
and 1376, occurred over a 23 year interval and thus was contained in a more
homogeneous population than were the longer lived nuclides.
.
iy
t
f
"4
Figures 22 and 23a and 23b summarize the 905, dose equivalent results for
individuals at Rongelap.
In this analysis, only the ingestion pathway was considered important.
Some radioactivity would enter the body vie the resuspension and direct inhala-
tion pathways.
It is known that for a given soil concentration of ‘the stab!c
45
»
naturally occurring analogs .to the radionuclides
considered here, the ration
oe
of food and fluid intake to blood relative to airborne intake to blood, are
as
‘
follows:
Co > 3000
zn > 130
Fe > 550
Sr > 10,000
4
Cs > 400
Thus, dietary intake of radioactive material is the principal pathway leading to
8
internal deposition.
a
This applies to most nuclides in the environment, however,
aN
ait
there are notable exceptions including I, U, and Pu,
ay
External Exposure
wi
aM
A-value af .7J rade in tiseue of interest per rantgen, measured in air at
s
One meter above the surface, was used to convert exposure in air to absorbel dose
X
in tissue.
:
The source was assumed to be an exponential diacribution of 17s ac-
tivity with depth in soil, typical of aged fallout (Be70).
Because of the
multidirectional nature of the source, variation of absorbed dose with depti of
organ was minimal.
Additionally, external doses were adjusted for living pat 43
7