characteristic of the alkaline solution of Ca(OH),, bnt the pH of the water-surface burst
fallout was about the same as ocean water, 7.5 to 7.7.
Approximately 25 percent of the particulate matter was not radioactive. The e-a)aation of this number is uncertain due to the possible introduction of dust into collector
trays. One sample from Site Huw indicated that 33 percent uf the activity was assoviated
with particles greater than 225 microns in diameter. A iarge fraction of the activity wae
also found to be associated with very~small particles, but these could have veen the result of particle break-up in the sizing procedure. Radioautographs of partic'va revealed
‘ooo
Topote
—t-
—
—~4—tofu ot.
Joy
deep
Particle Diameter, microns
tee
10
ao
00801
O02
O8
.
2
3
10
200
(B40
6D
80
O76
a)
a6
98
oe
97
00.8
888 Oe
oo 08
Percentage of Particlas with Smatler Diameter
Figure 3.11 Cumulative particle-size distribution.
some with activity only on the surface, others with activity irregularly distributed, and
still others that were radioactive throughout. The angular~shaped particles usually had
the activity on the surface, whereas the uniformly radioactive particles had a sphercidal
shape.
The average particle density was 2.4 gm/cm’
Samples collected on aerosol filters after Shot 1 revealed the same types of particulate: angular with surface activity and spheroidal with a volume-distributed activity. A
water leaching only removed 24 percent of the activity, whereas about 96 percent was
removed by weak acetic acid. Aerosol samples were collected aboard the ships (YAG's)
stationed {n the fallout zone during Shots 2 and 4. The activity appears to have arrived
principally in water droplets.
Chemical analysis of the samples was used to separate the fallout composition into
coral, sea~water, and device contributions by evaluating the Ca, Na, and Fe contentof
52