69
induced activities (59Fe, 57:58.60Co, 54Mn, 144Cs-
144Pp, 957.95Nb, and !°6Ry-106Rh), Radiological assessment has included surveys for gammaradiation levels on the islands; radiochemical studies of
soil profiles, lagoon bottoms, marinelife, plants, animallife (¢.g., rats, coconut crabs), food items, and
urine samples; and gamma spectrographicanalysis
of internally deposited gammaemitters in personnel. The medical team has been responsible since
1969 for monitoring the body burdens ofthe people
returning to Bikini, as well as ofthe Marshallese ex-
posed to fallout and their controls, and morerecently also of the people returning to Eniwetok.
The 1974 studies of environmental radiation on
Rongelap, Utirik, and Bikini are being published
separately. 165
Until 1965 gammaspectroscopy was done ina
21-ton steel chamber built at BNL for shielding,
with additional housing for the counting equip-
ment (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” arrangementof lead bricks, a modification of the
radaga
|
E
——— Rongelap male
3,000 [-
—+-- BNL medicai team 4
male
|
1,000 -E
500 E
-
F
100 E
\
\
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
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 gammaemitters and 9Sr for the Rongelap people at various times after the initial exposure in 1954. After their return to Rongelap the
body burdens increased. ®5Zn was present for a
few years, apparently from fish in the diet; the rea-
son for its rapid decrease was not immediately ap-
parent but may be related to movements of marine
life in and out of the lagoon. Small amounts of
6Co were identified 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.
~
“.
A
N
i
\
Radionuclides in Coconut Crabs From Rongelap
Year
1964
‘A }
y
0.4
Table 40
7
|
0.8
Energy (MeV)
1.20
137Cs, pCi/kg
1.60
1965
1969
1972
1973
1974
90Sr, pCi/g Ca
1,140
1962
Figure 35. Gammaspectra obtained by whole-body
counting, males, 1974 (——, Rongelap; -~-, BNL medical team).
SO0b 1 bb
water, and crabsover the past 5 years are sum-
1961
OK
A
50
10 0
radiochemical analysis.
The results of radiochemical analyses ofurine,
3
4
Activity (counts/15 min)
10,000
the low levels present in the people (see Figure
35).167.168 Annual collections of 24-hr urine samples from a numberof people have been madefor
4
J
uw
md
“4
Hanford model!96 (Figure 54). In 1974 spectro-
graphs showed a characteristic peak for !37Cs and
65Zn, but 8°Co was barely discernible, if at all. at
1,224 (1,317; 1,086;
50,281 (39,292; 45,318;
66,234)
12,700
7,775 (8,540; 7,010)
5,900 (5,600; 6,100:
12,900*
6,800; 5,100)
37,065 (64,700; 9,430)*
6,600 (5,000; 8,200)
4,800*
1,113; 1,378)
758 (865; 628; 780)
724
705 (910; 500)
353 (376; 419; 359;
_
933*
.
259)
3,950 (6,639; 1,267)*
448 (290; 606)
290*
“From northern islands of Rongelap Atoll, where radiation dose was much higher.