subgroup at a constant level in prior years.

Because this level is at or near

the system MDL it is a conservative estimate of the mean body burden of the
population.

The nuclide 297B1 has been detected in the Enewetak people in 1981 and
again in 1982 at levels that substantially exceed the system MDL.

In 1981,

one individual was determined to have a 207 Ry body burden of 12 nCi.

year the highest value was 6.3 nCi.

This

In the adult male population 15

individuals had body burdens in excess of 1 nCi while in adult females 6
individuals had body burdens exceeding 1 nCi.

These data indicate that

20731 is being incorporated into the diet of the population in increasingly

larger quantities each year.

‘

Discussions with Bill Robison and Vic Noshkin on January 22, 1982
indicate that the 297Bi and possibly 60co result are reasonable estimates
of the population mean body burden.

According to Dr. Noshkin, activity

concentrations in Enewetak fish for 2075; 60¢9 and 137¢g are 1 pCi/g,

1 pCi/g and 0.8 pCi/g respectively.

Using an average residence interval of

two years, these activity concentrations, the Robison diet (UCRL 53066 p 40)

and the retention functions for 2°7B1 (NUREG/CR-0150-V-2) and ®9Co
CORNL/NUREG/TM-190),

the predicted body burden for 20781 falls into the

-

range of 0.24-0.70 nCi and the predicted body burden for 69¢o falls into the
range of 3.5 - 10.4 nCi.

These estimates are highly dependent on the

retention function and the assumed dietary patterns.

Further discussions with

Drs. Robison and Noshkin revealed that the presence of 20733 and 60¢o may
also be enhanced for the Marshallese if they eat the entire fish since 20754
and 6%are present at higher concentrations in the fish intestinal content

and liver.

Drg. Noskin and Robison also stated that there were detectable

quantities of transuranic elements in the non-edible parts of the fish and
that LLNL dose projections do not assume that the entire fish is ingested.
This dietary question will be investigated on the next field trip to Enewetak
Atoll.
The rise in the adult male !37¢g body burdens was investigated while
the field team was at Enewetak Atoll.

Comparison of the first 20 adult male

results with past body-burden histories indicated that some individuals were
exceeding prior levels.

Individuals whose current 137¢g body burden

exceeded 75% of the maximum }37¢g body burden observed in their population
subgroup during 1981 were interviewed privately following the whole-body count

in an effort to determine recent changes in living pattern or dietary habits.

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