confidence level and is obtained

from

mic mean exceeded tes,

the

observed

standard tables, and comparing the

bias was said to be significant

value of C°sp with py.

with a$5 percent level

If the logarith-

of confidence.

Initial Processing of Field Samples
SOIL SAMPLES

blew warm air into each unit, which

Soil samples, by far the largest

was equipped with a fan in the vent

category, were treated similarly to

pipe.

those samples obtained during the-

in a large commercial drying oven

1972 Enewetak Survey. ~

at 150°C.

The treatment

consisted of drying, pulverizing,
blending,

screening,

packaging,

preliminary gamma assay.

and

Three

Final drying was accomplished

Samples were ground in a l-gal
paint can using eight l-in.
balls.

The cover

of

each

steel

can was

separate aliquots were produced from

taped securely;

each soil sample:

was covered with a galvanized-steel

can"

an aluminum "tuna

containing 300 to 350 ¢ and

two vials containing 50 2 each.
The soil-processing facility was

then the entire can

jacket that was held in place by two
large rubber "0" rings to prevent
the lids

from falling off during ball

carefully surveyed for possible

milling.

radioactive contamination.

could be milled overnight to provide

<Air-

Filter samples and swipe samples

15 to 24 h of grinding.
Packaging, weighing, and labeling

taken from the floors were analyzed
For

60

Co,

content.

137

Cs,

and

There was

contamination.

2394240

The

Pu

A maximum of 48 samples

of samples were performed by hand.

no detectable

All work with finely divided soil was

area was

performed in fume hoods.

considered suitable for initial

sample was packaged,

processing of soils.

laid

This monitoring

out

on

Before each

clean paper was

the hood bench.

Care was

program continued throughout opera-

taken to prevent cross-contamination

tion of the facility.

of samples.

Drying ovens designed and built for

The following is a detailed chrono-

the Enewetak Survey were used for

logical description of

initial drying of samples at approxi-

e

mately 70°C.

Two ovens were con-

the operations:

The samples were first unpackaged
from the shipping container and

structed of asbestos board with steel

logged.

shelves inside;

sample was noted (e.g., amount of

+

eee
on
£e7

ee

=

two 300-W air heaters

The appearance of each

Select target paragraph3