of young cordia trees,
and exhibited the highest levels
encountered on the 0 Transect.
recorded at Location 8 at
1400
Much lower
levels were
ft.
The spectrometric results indicate that the predominant
radionuclide present in the soil on Bikini was **°’Cs with
lesser amounts of °°Co and ***Sb.
These were the main
contributors to the total exposure rate.
Of these three
isotopes, ~*°”Cs contributed 76 to 78% of the total exposure
rate and *°co and -**Sb were each responsible for about 10
to 12%.
Cbhjects of scrap steel such as abandoned steel cable
reels often showed high ©“co contamination and this produced
a higher local total exposure rate.
In the analysis of the spectrometer data it has been
assumed that the radionuclides are distributed exponentially
in the soil with a 2 cm relaxation length.
This is consist-
ent with the laboratory analysis of soil samples taken at
Locations 5 and 7 and from the area cf the clearing experiment.
Non-uniform distribution of the gamma emitters and
neglect of minor contributors is reflected in the small
discrepancies between the icnization chamber and spectrometer
total exposure rates given .n the above table.
Considering
the general non-uniformity in fallout distribution throughout
this
good.
area,
agreement between the two measurements
For all the iccations,
is quite
the values agree te within 10%.
re
Exposure rates were also calculated from the results of
the laboratory analysis of the soil samples taken at Locations
5 and 7.
These values are given below together with the
percentage cf the tctal exposure due to each isotope.