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 pr/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 8° co
and **®sb.
On Nam and other islands closer to blast sites
®°co was the main contributor with important contributions
from +25 cp, 1°2Mpnh, and sometimes *°"Cs.
Other. isotopes,
including *°’Bi, **°nu, **?Eu, °®gn, *°*Rh, *°*Rh, ***Ce,
and ***am, were also detected occasionally.
The range of radiation levels on each island are summarized
below.
SUMMARY OF RADIATION LEVELS — GAMMA EXPOSURE RATES
(jr/hr)
Exposure Rate
Isiand
Bikini
Weathered Areas
Contributors}
10-120
*37 a5
16-30
Close-to-Shore
Island Center
Hot Spots
20-40
50-80
80-120+
Outer Edge
Island Center
10-30
15-150
Eneu
Nam
N.E.
2-10
10-330
Corner
Bokantuak,
Rojkere,
3-10
Eonjebi
- 40 -
eee eee
*37Cs
°°co, *37es
110-330
Iomelan,
Me roam
Major
Range
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eg ee eg ee
=
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