-~ 14 -
-055
EO
~
CoD?
100
gO
80
A - Silverstein plankton
B - Collett plankton
70
60
Activity
50
ho
30
20
10
Fig. 4.
Gamma spectrum curves of combined plankton samples
of the Collett and of the Silverstein survey which
was conducted three weeks Tater.
WiS5 was present
at a high level in the plankton from the Collett
survey but was absent in the plankton from fhe
Silverstein survey.
The Collett samples contained
higher levels of radioactivity than did the Silverstein samples and the gamma curves are not indicative
of the relative gamma activity in the two samples.