-~ 20 the survey area, which finally covered 78,000 square
miles.
Radioactivity diminished in value around the
edges of the sampling area,
vey had,
in fact,
indicating that the sur-
encompassed the waters in which the
heaviest contamination would be found.
Counts of
activity in the surface waters were considerably
higher than those down to 100 meters,
for the fallout
deposited on the surface during the tests had not yet
penetrated the stirred layer.
ples had an average value,
The surface water sam-
for the 3,300-mile run,
of
10,000 disintegrations per minute per liter of total
beta radioactivity, whereas water sampled from the
100-meter depth had the lowest average content,
3,900 disintegrations per minute.
about
It was noted that,
while measurable amounts of activity were found in
the waters of each station sampled, the lowest values
were found in the northwest part of the survey area,
in that part where the survey had started, while the
highest readings were found immediately north and
west of Bikini,
where maximum readings of 120,000
disintegrations per minute were recorded.
The pattern of plankton contamination was a
magnification, many times over, of the contamination
in the water.
The average value of radioactivity in
plankton was 71,000 disintegrations of total beta
activity per minute per gram, the highest value,
found
in a sample taken north of Bikini, being 1,200,000
disintegrations per minute.
basis,
On a weight-for-weight
the average value of plankton radiation was
7,000 times that of the
surface water.
The minimum