°
3
The gross beta activity of the top two one inch increments
has been determined.
Samples from tne northern end of the atoll
have, in general, more activity than those from the south.
Anal-
ysis of radiation data relative to types of bottom sediments re-
mains to be done.
.
Vertical distribution has been determined for 26 samples
to a maximum depth of 35 inches.
in the top two inches.
Radioactivity is primarilly
The picture is not as clear cut as for
the soils probably due largely to the fact that the levels of
radiation in the bottom samples are low (maximum 127 c/m for a
1 gm sample counted.with
30% efficiency).
Low level beta counting of the fine fractions is in progress
and thus far indicates that most of the activity is associated
with
the fines.
Gamma ray spectra indicate the presence of cet44 ana Eul5>
excert Ru& Band Ce ee
and none of the higher energy zamma emitters~
Chemical separa-
tions will be necessary before precise identification and quantification can be made.
ples,
Since this will require pooling of sam-
the chemical separations have been deferred pending com-
pletion of beta counting.
Beach rock samples snow no radioactivity above background.
9002213