-32-
depth of at least two feet in only slightly reduced degree.
No information is available on the radioactivity of lagoon bottom
material deeper than two feet, but from the slight decrease thus indicated at two feet
the activity may be assumed to have penetrated
farther, constituting a reservoir estimated to exceed 20, 000 curies
of beta activity in the first meter of lagoon bottom in August
1958.
This amount may be compared to 54, 000 curies (380/0. 7) estimated
(UWFL-43:56) for the top eight inches in 1955.
Comparison of Plankton and Bottom Samples
Plankton values might be expected to correlate with bottom sample
values (Fig. 10}.
In a comparison of activity in August 1958 between
pumped plankton and bottom samples at the ten stations, the positive
correlation coefficient fell somewhat short of statistical significance,
even omitting the first station, at which an exceptionally high plankton
value was found.
However, values for plankton tows at Stations 3 and
4, 5 and 10 near Rongelap Island, Eniaetok Island, and Kabelle Island
“were negatively related (non-significantly) to the values for bottom
samples at the corresponding localities.
Thus, there is no evidence
of correlation between radioactivity of plankton and of bottom samples
at the same locality.