347
NOTES
consisted mainly of coconut, pandanus and breadfruit trees but included a garden development
where squash, papaya, bananas and other crops
were grown (Ro77). During the maturation interval
for most of the tree crops (5-7 yr), the majonty of
the food consumed on Bikini Island was imported
by Trust Territory supply vessels. As the local
vegetation developed, the diet became less res-
Whole body counting was performed in 1974
and 1977 by the BNL Medical Department (C075;
Co77), and the program continued in 1978 under
the BNL Safety and Environmental Protection
Division along with the follow-up whole body
counting of former Bikini Island residents currently residing on Ejit or Majuro Islands, Vfajuro
Atoll and on Kili [siand (Mi80), Field measurement
contained substantial quantities of locally grown
items.
Bioassay and external exposure monitoring programs were initiated for Bikini Island residents in
anticipation of the changing dietary situation, and
with the realization that it was essential to do
personnel monitoring on those individuals living
on Bikini [sland.
Extensive external radiation monitoring was
performed in 1975 through the joint efforts of
Brookhaven National Laboratory and Lawrence
Livermore Laboratory. Data were collected using
an environmental ionization chamber to quantify
exposure rates, portable Nal scintillation survey
meters to map the external radiation fields, a
portable gamma spectroscopy system to define the
major energy componentsof the external field and
to determine energy dependence correction factors
for the ion chamber. and LiF thermoiuminescent
complished with a trailer-mounted shadow-shield
whole body counter. Dose commitments were
calculated from the measured body burdens
for many persons residing at Bikini [sland dunng
the years 1969-78,
In addition to retrospective dose equivalents,
whole body counting and bioassay techniques provided the data base from which dose equivalent
commitments were calculated. These caiculations,
together with external radiation measurements,
provided a complete assessment of dose to the
Bikini population from chronic exposure to important fallout radionuclides in their home atoll
environment.
tnicted to imported foods so that by 1978, the diet
dosimeters
exposures.
to measure
long term
integral
External exposure estimates were
developed based on these measurements and an
assumed living pattern (Gu76; Gr79).
Urine samples for radionuclide bioassay were
collected during BNL medical field trips to Bikini
between 1970 and 1976 (Co75, unpublished
results), This program was reinstated by BNL
Safety and Environmental Protection Division in
1978 with systematic 24-hr urine collections from
all adult Bikintans. Urine bioassay results were
used to calculate ™Sr-"Y and '’Cs-'""Ba body
of y-emitting radionuclide body burdens was ac-
Results
In the following tables, the dose equivalent during the residency interval and dose equivalent
commitments to bone, bone marrow and the total
body are presented. The means for the dose
equivalent and dose equivalent commitment were
determined from individual data points which
represent a wide distribution of residenceintervals.
The mean value corresponds to residence interval
(years) for the population described. Residence
intervals were determined through verbai interrogation of participants in the personnel monitoring
program.
Tables | and 2 represent the bone and bone
marrow mean doses and ranges in mrem which
were the result of ingesting Sr-Y during the
burdens and resultant radiation dose equivalents residency interval. These data were derived from
for all Bikinians from whom a satisfactory urine © measured urine activity concentrations during the
uptake period. Constant continuous ingestion of
sample was obtained.
Table t. Se.¥ Some dosimetric averages for Bikinians
Dose Equivelient
Comicmesac, sien
Dose Equivalent Ouriag
Residence Llaocerval, oies
Fopual stica
Bescrigtion
Nuaber
of Persons
Mees Residence
Interval, feare
Mesa
High
Range
Low
Range
Low
Mean
Sigh
7.3
adult anles
19
4.2
28
129
39
Co
2%
Adult feusies
3
&.l
15
42
«35
42
110
5.8
3
5.3
a7
120
t3
130
316
23
Male childrea
ae