FALLOUT IN THE OCEAN
INTRODUCTION
The following discussion of fallout in the oceans is,
the most part,
a discussion of local,
for
not stratospheric fallout.
Local fallout is defined as the fallout that occurs during the
first day or two following the detonation of a nuclear device
and within a few hundred miles of ground zero.
Local fallout
differs from stratospheric fallout in several important aspects.
In an area of local fallout the amount of fallout per unit
area and the size of the fallout particles are considerably
greater than in an area of stratospheric fallout only.
Fora
surface explosion 65 to 85 per cent of the fallout may be local
and for an underwater detonation local fallout may be even greater.
Also, the chemical form and the percentage composition of the
radioisotopes in the two areas may differ.
For the megaton
weapons fired in the Pacific the bulk of the fallout resides on
particles of CaO or Ca(OH)2 or mixtures of Cao,
caCO3z
Ca (OH) 9 and
made by the great heat of the fireball acting on the coral
of the islands and sea floor.
A large amount also is carried on
NaCl particles
The large particles of these com-
(Libby,
1956).
pounds fall out locally and do not enter the stratosphere.
a consequence greater quantities and different species of
As