IV.
SUMMARY AND CONCLUSIONS
An intensive external radiation survey of Bikini Atoll
was carried out during April and May of 1967.
Total exposure
rates were found to vary considerably from island to island
and from site to site on a given island.
Levels measured
over soil ranged from less than 10 pr/hr to over 500 ur/hr.
(External gamma radiation levels in the United States due to
naturally occurring emitters in the soil range from 0 to
about 20 ur/hr.)
On Bikini and Eneu Islands the major
contributor by far to the total exposure rate was found to
be **’cs with minor but significant contributions from S° G0
and **®sb.
On Nam and other islands closer to blast sites
®°co was the main contributor with important contributions
from *#°sb, *°*™Rh, and sometimes **’Cs.
Other isotopes,
including *°’Bi, **®Egu, *®*Eu, ®®2n, *°°Rh, *°* Rh, **"Ce,
and 24 am, were also detected occasionally.
The range of radiation levels on each island are summarized
below.
SUMMARY OF RADIATION LEVELS - GAMMA EXPOSURE RATES
(jir/hr)
Exposure Rate
Island
Bikini
Weathered Areas
Close-to-Shore
10-120
+3765
10-30
20-40
50-80
Hot Spots
80-120+
Nam
Outer Edge
Island Center
N.E. Corner
erate elerthtpetree 1 wn
Contributors
Island Center
Eneu
Bokantuak, Iomelan,
Rojkere, Eonjebi
Major
Rance
2-10
10-330
10-30
15-150
110-330
37 os
®°’co, *37cs
3-10 gepartment of Energy «
Historian’s Office
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