August of 1934 This method of estimauny “Zn
dau acuivit. ingestion rates yields a j&-times
greater estimute of tots. intake than the total
Intake Ssuggesies pV bouy-burden extrapolation
techmigues scuuahons «7)). Although the Zn
Told; take estimate incicated for Link adults
in Tabie 4 was basec on seanty datu. i was
made with fewer assumptions than was the
above estimate using Japanese fishing data.
The vaidity of the ~’Pu data used to estimate
the body burden at Rongelap Atoll (see Table
1} in 1973 had been considered by an Energs
Research and Deveiopment Agencyad hoc commitiee. The committee concluded that because
of the possibility of urine-sample contamination
these data were uncertain. This may indeed have
been a facter since a radiochemical analvsis of
BRAVO ceoris indicated Rongelap Atoll was
contaminated with “Pu (Ts55). No special pre-
cauuons had been taken when the urine sampies
were collected in the held. therefore not much
credence could be given to these data.
In 19%6. three male adults at Rongelap Atoll
provided urine samples for -“Pu analysis. Twe
vielded results below the minimum detection
limit of 3.7 x 107* Bq l.~' (0 fCii.~') and one
yielded 3.3 » 10°* Bqt.” (90 fCi1.~'). The aver-
at this time. Several investigations are underway. In August 1981]. fecal and urine samples
were obtained from Rongelap and Utunk residents and ure to be anatyzed after complete
dissoluuion followed os a liquid solvent extraction techmique usec in conjuncuion with a
photon-eleciron reiecting liquid scintillation
spectrometer developed by McDowell] for lowlevel alpha spectroscopy (Mc72). The question
ofiniual sample contamination will be answerec
fe Jowing additions. analvsis of urine collected
in 1980 from former Bikim: Atoll residents.
the committed effective dose equivalent; the
overall body-burden pattern was one of initial
increase followed bv continuous decline over a
period of vears: the daily intake pattern was
probablyone of continuousdecline, this conclu-
sion was based on the fitting of sequential
bods-burden data to equation (2): the impact of
each nuchde on internal committed effective
dose equivalent was dependent upon the time
between contaminauon and rehabitation: and
the internal committed effective dose equivalent
exceeded external dose equivalent during the
rehabitation period. The sparse *’Pu data indi-
cated further research was necessaryto estimate
accurately the activity intake and committed
committed effective dose equivalent since they
may have been the result of an erroneous urine
because the population reinhabited within
months of the BRAVO event. The impact of
nuclides with a long mean residence time in the
diet (Cs, Sr, Fe) was greater at Rongelap
nal deposition. The potential for contamination
also existed for *Sr, however the impact of
contamination on dose assessment was much
greater for Pu.
Questions concerning the ”*°Pu estimates have
led to a study of the sampling and analysis
procedures which indicated that some ~*Pu in
urine may not have been chemically recovered
along with the tracer (Ry82). The extent of
sample contamination during collection and the
fundamental reasons for variation in recovery
of *°Pu from urine samples remain unanswered
tor.
The principle results of this investigation were
that: '’Cs and “Zn were major contributors to
effective dose equivalent from this nuclide.
For committed effective dose equivalent, the
collection technique and not the result of inter-
doc.
CONCLUSION
age of these values along with the 1973 adult
average data that was reported by Conard
(Co75) were used to derive potential body burdens. The results were listed in Table 1.
The estimates for “*Pu adult body burden
were not used to derive values of intake and
ergs
Wit
7 x 10 Ba d~
lew
been
impact of nuclides with a short mean residence
time in the diet (°°Zn, Co) wasgreater at Utirik
because of greater initial contamination.
Acknowledgments—The authors fully appreciate the
fine efforts of Michael Ryan of Oak Ridge National
Laboratory; Nathanial A. Greenhouse of Lawrence
Berkeley Laboratory; Lee V. Kaplan formerly from
Yale University; Humbilena Manalastas from the
Philippine Atomic Energy Commission; William Ad-
am$, Jan Naidu, John Baum, Victor Bond, Donald
Borg, Eugene Cronkite, Andrew Hull and Charles
Meinhold from Brookhaven National Laboratory;
and Thomas McCraw from the Department of En-
tomo 7)
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