- §2 -

oe top 6 inches of soil on the island proper.

A similar comparisonfor Ronge-

lap Island gives values for lagoon sand of 2/11 to 2/5 that of the land soil.

. At Enibuk the soil and lagoon sand were essentially equal inlevels of radioactivity.
In sand profiles taken at Kabelle and Rongelap Islands the radioactivity

levels of samples taken in water depths of less than 25 feet were approximately 1 1/2 times those found in samples from 50 to 60 feet of water.

Bot-

- tom samples obtained from the anchor chain in 150 feet of water off Rongelap
ee Island and Mogiri Island (Ailinginae Atoll) contained from 0.7 to 1.2 times
’ as much radioactive contamination as was found on the islands proper.
Comparisons of the distribution of radioactivity in the top 6 inches of
soil and lagoon sand were madeand are as follows.
Percent of
radioactivity
in top 3 inches

Island
Kabelle soil
Lagoon hottom off

97

3

Rongelap soil
Lagoonbottom off

57
97

89

43
3

Kabelle
Labaredj soil

_

Percent of
radioactivity
in 3 to 6
inches depth

Rongelap

Lagoon bottom off
Enibuk

55
42

St ee

11

45
58

Thus on land most of the activity is concentrated in the top 3 inches whereas

;

Under water it is distributed throughout the top 6 inches (Fig. 14 A).
Sand profiles from the lagoon off Kabelle Island under 6 and 60 feet of

.

Water, from off Rongelap Island under 22 feet of water, and from the Enibuk
_ low tide line

were fractionated according to particle size as follows: greater
awe UNIVEs wees

UNr,

wa

ae

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