ta
“_—
eae a a
Rhee dee a od
:
a
ae ee de ee ne cil ee me
use of crystal detectors and a gammaspectrum analyzer in conjunction with a
thick-walled steel room to lower background radiation. With this arrangement
radioactive contat until they were
sorption of radiofood and water.
internal levels of
it was possible to measure directly very low levels of radioisotopes. Several
Marshailese were measured by this procedure at the Argonne National Laboratory in 1957. Later a steel room, constructed specifically for these surveys
(Fig. 9), was taken aboard Navy vessels to Rongelap for the four and five year
surveys where a large number of Rongelap people have been measured at their
ries: _Todine!3!- 135)
homeisland.
Rongelap Island remains slightly radioactively contaminated butis considered’
naller amounts of
elivered a dose of
on of radioisotopes
iminution of body
nary activity was
since the return of the people to their island. Based on gammaspectroscopy of
based on urinary
direct method of
issible through the
Zn* (which is selectively concentrated by the fish, a main item of the Rongelap
diet) increased to an estimated mean body burden of 0.36 uc urinary. Excretion
rates of Sr® increased by a factor of about 20. Increase in body burdens of
isotopes occurred equally in unexposed and exposed populations andthelevels in
the exposed group are about the same as in the unexposed group living there.
safe for habitation. This is reflected by an increase in body levels of radionuclides
the isotopes, it has been estimated that during the first year after their return
Cs!37 increased by factors as high as 60 resulting in a body burden of 0.68 ttc.
1900
——
Cs'*".)
NET IN VIVO GAMMA-RAY |
SPECTRA OF MARSHALLESE ]
SUBJECT (NO 79)MALE,
AGE 44
zn%
[
Zz 'O > marcy i959
z
=
o
4
CHANNEL WIDTH
20 kev
4
1
7
+
~
mi
w
4
z
°
>
3
~
n
1
‘
|
MARCH 1957
]
CHANNEL WIDTH
50 kev
49
_
4
3
1
oO
I
ue
4
jou
.20
{
40
1
6s
!
680
Mev
1
1.0
!
1206
\
140
160
Fig. 10: Gamma ray spectroscopy of Rongelap man in March 1957 and March 1959
Based on preliminary analyses of data from the most recent survey period,
eight to twenty months after the return to Rongelap, it appears that the people
are approaching an equilibrium with their enviroment. The body burdens of
Cesium!37 appear to be slightly lower than the previous year while the Zinc
body burden increased about 8°/o, The Strontium® analyses, unfortunately, are
™~
ei
ns
Mg,
é
CsI
rani#
325
q8