~-47-
An idea of the amount and distribution of radioisotopes
in the North Pacific Ocean at the present time -- a year and
one half after the last test series at Bikini-Eniwetok ~- can
be gained by again referring to the report of Operation Troll
by Harley.
One year after the 1954 series a two-month survey
was begun near Bikini and continued westward to the Philippine
Islands,
then northward to Japan.
The course of the vessel
between Bikini and the Philippines was southwest, northwest
and again southwest,
a course that three times cut across
westward flowing North Equatorial Current.
From the Philippines
the course was southward a short distance to Morotai,
northward to Japan.
the
then
Analyses of the sea water and plankton
samples indicated that the radioactivity was of low level and
widespread.
The radioactivity in water from other than natu-
rally occurring radioisotopes ranged from 0 to 570 disintegrations per minute per liter and in plankton from 3 to 140
disintegrations per minute per gram of wet sample.
At the
station with the highest value twelve samples were taken
between the surface and a depth of 653 meters and the average
of the twelve samples was 190 d/m/l.
By comparison, the radio-
activity in sea water from naturally occurring K49 is 736 d/m/1.
The low
the
North
values were
beginning of the
Equatorial
found to be
survey;
Current,
at
east of Bikini
the
although
outer
this
Atoll at
edges of the
was difficult to