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