conducted at Rongelap Atoll by Dr. V. Noshkin;
the sources of the data are identified in the
table footnotes. The data in the tables have
Radionuclides in Terrestrial[Foods
been decay corrected from the date of the
The mean concentrations of radionuclides in
food crops grown on RongelapIslafd are listed in
Tables 5 and 6. The numbers of samples that
Radionuclides in Soil
values, as well as the median And range of
values, are listed in Appendix B.
The
distribution of our sampling site on Rongelap
reported results to our target date of 1995.
The median concentration of 137Cs, 90Sr,
239+240Pu, and 241Am in surface soil for interior
and village areas, and soil profiles on Rongelap
Island are listed in Table 4. The decrease in
activity with depth is exponential with about
80% of the activity in the top 15 cm ofthesoil
column.
We have included in the diet model,
100 mg/d of surface soil that may contaminate
the food during preparation or on the handsof
the people where it might be ingested.
Consequently, for the Imports Available diet,
were averaged to derive eachfof the mean
Island is shown in Figure 2.
The concentrations of 137Cs fin foods from
RongelapIsland, based onall the fata from 1986
through 1993, are compared in Table 7 with the
adjusted values used in the 1942 preliminary
assessment (Robison et al., 1982) ghat was based
on the 1978 NMIRS.
The reason for adjusting th
1978 data is
personnel conducting the survep
collected ail
outlined below. During the 197 NMIRS, U.S.
coconut, Pandanus, breadfruit, other vegetation,
and soil samples. All of the cocongts collected on
surface soil accounts for 56% on the 239+240Py
daily intake, and 72% for the 241Am daily
intakes. For the Imports Unavailable diet, soil
ingestion accounts for 22% and 39% for the
Rongelap Island (and the otherjislands) were
assumed to be drinking coconufs. The 137Cs
concentration of 0.20 Bq g-! (5.5 pri giin these
negligible compared to the other foods. In Tables
5 and 6, the mean surface soil concentrations for
137Cs, Sr, 239+240Pu, and 241Am are presented to
drinking coconut meat value ang was taken as
village versus the interior of the island. We
assume people spend 16 h d-! in the village, 1h
d-1 on the beach, and 7 h d-! in the interior of
Rongelap Island. More detailed results showing
assistants select and classify the coconuts as
information for the village and the interior of
RongelapIsland arelisted in Appendix A.
The majority of 241Am in soil profiles below
10 cm are under the minimum detection limits.
The values for 241Am presented in this report are
ratio of the coconut meat. If the c@conut meat dry
samples collected and analyzed since we do not
report values below the minimum detection
limit. Therefore, the statistics presented would
be much lower if we had real values for the
coconuts collected in 1978, we find that most of
239+240Pu and 241Am daily intakes. The daily
intake of 137Cs and 99Sr via soil ingestion is
account for the time distribution spent in the
coconut samples was used for the drinking coconut
meat value in the dose assessmegt. A value for
copra meat was estimated from fhis “assumed”
0.28 Bq g-! (7.6 pCi g-1).
As we progressed with our prderam
to the present, we have hagl
from 1979
Marshallese
drinking or copra coconuts. Wq@ found that we
could differentiate between drinking coconuts
mean, median, ranges and other statistical
and copra coconuts, as selected by the
Marshallese staff, by measuring|the dry to wet
based on only a small number of the total
to wet ratio is greater than 90.45, then the
coconuts fall into the copra class] and if the ratio
is less than 0.45, they fall intb the drinking
coconutclass.
When we apply these qriteria to the
samples that gave us minimum detection limits.
For the soil depths of 10-15 cm, 15-25 cm, 25-40
and 40-60 cm the percent below the minimum
detection limit are approximately 50%, 70%,
80%, and greater than 80%.
the coconuts collected by U.S. pgrsonnel in 1978
were really copra coconuts; only three of the
seventeen coconut samples| ollected were
drinking» coconuts.
pavently: the
the 1982 dose assessment was
the drinking coconut class beds
concentration is higher in copra oconuts
drinking coconuts.
16
than in