24
water as
tion in the surface layer,
where phytoplankton is most abun-
coupled with the facts
dant»
This greater concentra-
it does at greater derths.
thet plankton nas e higher spe-
cific activity than water and that a few samples of microrlankton taken during Operation Troll showed an even higher specific
activity than the macroplankton suggests that the microrlankton may be the principal source of the radioactive particulate
matter.
The aotivity in the particulate matter was measured from
surface
samrles teken every half-hour
(approximately every &
miles) while approaching and leaving station 62 off the western
end of Bikini..
Wester for these samples was taken from the out-—
let of the tank for continuous monitoring.
The results (Pig. 6)
indicate that some radioactive meterials are being eluted from
Bikini Atoll to the northwest.
However,
these materials probab-
ly add only an insignificant amount to the total activity in the
area between Bikini and Eniwetok.
The discrepancy between the
activity in the sample taken from the tank and that taken from
the water bottle at the station off Bikini is probably largely
due to a lag in passage of water through the tank.
Continuous Monitoring
The scintillation probe used
DOE ARCHIVE
is successful for the deter-
mination of levels of aotivity in contaminated sea water during
the first few weeks following the detonation of a nuclear device;
however,
on the basis of our limited experience,
the probe is
not of sufficient sensitivity for the measurement of low levels
of Y
aotivity in sea water as late as two months fol. owing