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in Table A.I, Appendix. The activities were either imperceptible or of
2
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Soil
To describe the downward movement of the activity, profile soil same
ples were obtained in increments to a depth of 56 in. As shown in
Table 2.1, the greater part of the beta activity appeared fixed to the upper
surface of the soil; the remaining part diminished sharply and progressively at deeper levels, The bulk of the activity appeared to be firmly
absorbed to the soil since it resisted the downward migration of the heavy
rains to which these islands.are subject,
.
tne petRipewy
a lee oA ie a ah a ane |pled
ae davey
Table 2,2 lists the gamma dose rates found on the island survey; levels
observed | year before are included.
The gamma activity was reduced
over the 12-month period by 74 + 8 per cent.
Calculations based on the
Hunter-Ballou curves for beta decay of mixed fission products* predict
that 80 per cent of the gammaactivity is lost by radicactive decay over
this interval. This decay was obviously the significant factor in reduction
of the gamma field rather than the leaching of nuclides to deeper layers
.
--g =
a 8 MTA a Te
and their eroding into the adjacent waters.
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