4g
SUMMARY
1.
A survey of the radioactivity in the sea water, plankton
and fish was made in September 1956 in an area bounded by 9° N
and 15° N and approximately 145° E and 166° E.
2.
The general pattern of distribution of activity in the sea
shows a sharp decrease in activity east of Bikini and a gradual
but irreguler decrease west of Eniwetok.
3.
Plankton appeers to be the most sensitive indicator of
radioactivity in the sea;
the
average of ratios of plankton
activity to sea water activity was 2,500.
4,
The highest value of radioactivity in plankton, 21,000 d/m/g
wet, was found about 80 miles north of Fniwetok and the lowest
velue, 27 d/m/g, near Guan.
5.
The highest value for water activity, 19,009 d/m/l, was
found between Eniwetok and Ujelang and the lowest value,
48
afm/l. northeast of Bikini.
6.
Sea water filtered through millipore filters had higher
levels of activity than the residue on the filter paper.
7.
Mteroplankton is probably the principal source of the
radioactive particulate matter.
8.
The change of relative radioactivity of the water with
depth ts variable put appears to fall into regional patterns.
at!