69
induced activities (59Fe, 57-58.60Co, 54M{n, 144Cs143Pr, 99Zr-95Nb, and !°6Ru-296Rh). Radiological
assessment has included surveys for gamma radia-
tion fevels on the islands; radiochemical studies of
soul profiles, lagoon bottoms, marinelife, plants, ant-
mail life (e.g., rats. coconut crabs), food items, and
urine samples; and gammaspectrographic analysis
of internally deposited gamma emitters in personnel. The medica! team has been responsible since
1969 for monitoring the bodyburdens of the people
returning to Bikini, as well as of the Marshallese exposed to fallout and their controls, and morere-
cently also of the people returning to Eniwetok.
The 1974 studies of environmental radiation on
Rongelap, Uturik, and Bikini are being published
separately.165
Until 1965 gamma spectroscopy was done in a
21-ton steel chamber built at BNL for shielding,
with additional housing for the counting equipment (Figure 53). The subject to be counted took
a soap and water shower, put on paper pajamas,
and then stayed in the chamberfor about 15 min,
during which soft music was piped in. Only a few
small children were apprehensive during the procedure. More recently whole-body counting has
been done with a smaller “shadow-shield”’ arrangement of lead bricks, a modification of the
Hanford model!®(Figure 34). In 1974 spectroE
r
T
T
T
T
TT
r
50,000 cF
3
:4
Activity (counis/ 15 min)
4
10,000 —
=
Rongelap male
5,000 ~
-
---- BNL medical team 7
male
4
L
=f
1,000afL ‘\
‘
ean
l
00 -
44
\
[
.
Ny
iA
\
F
f
{
wi i
—_—
\
\
50
F
1
0
4
0.4
a
\
™
i
0.8
Enerev (MeV)
i
1
1.60
Figure 55. Gamma spectra obtained by whole-body
counting, males, !974(——, Rongelap; -—-, BNL medical team).
137Cs; its levels are given for Rongelap, Utirik,
and Bikini individuals in Appendix 12 and for
groups in Table 41. Since the return to Rongelap,
no differences have been seen between exposed
and unexposed groups.
Figures 56 and 57 show the estimated body
burdens of gamma emitters and 9°Sr for the Rongelap people at various timesafter the initial exposure in 1954. After their return to Rongelapthe
body burdens increased. §5Zn was present for a
few years, apparently from fish in the diet; the reason for its rapid decrease was not immediately apparent but maybe related to movements of marine
life in and out of the lagoon. Small amounts of
Co wereidentified in personnel during the early
years after the return (the highest concentration
was in clams). 9°Sr body burdens reached their
highest level during 1962 to 1965 at about 12 nCi
*Weare indebted to Mr. Edward P. Hardy, Jr., Director, En-
vironmental Studies Division, AEC Health and Safety Laboratory, New York, N.Y., for carrying out the radiochemical
analyses.
Table 40
Radionuclides in Coconut Crabs From Rongelap
Year
1964
2|
4
4
1.20
marized in Tables 37 to 40; the results of indi-
vidual urinalyses are given in Appendix 12.* By
1974 the only detectable gamma emitter was
4
—z
iL.
the low levels present in the people (see Figure
55).167-168 Annual collections of 24-hr urine sarnples from a numberof people have been madefor
radiochemical analvsis.
The results of radiochemical analyses of urine,
water, and crabs over the past 5 years are sum-
7
1
fo\
63Zn, but 5°Co was barely discernible, if at all, at
1961
1962
=
in
100 1
10
=3
graphs showed a characteristic peak for 137Cs and
1963
1969
1972
1973
1974
137Cs, pCi/kg
Sr, pCi/g Ca
1,140
1,224 (1,317; 1,086;
1,113; 1,378)
50,281 (39,292; 45,318;
758 (865; 628; 780)
66,234)
12,700
724
7,775 (8,540; 7,010)
705 (910; 500)
5,900 (5,600; 6,100;
353 (376; 419; 359;
6,800; 5,100)
259)
12,900"
933*
37,065 (64,700; 9,430)* 3,950 (6,639; 1,267)*
6,600 (5,000; 8,200)
448 (290; 606)
4,800*
290*
*From northern istands of Rongelap Atoll, where radiation dose was muchhigher.