The best method for controlling this problem was found to be through the use
of a pressurized garden-type sprayer to wet the surface around and at the
sampling location with water. By spraying a fine mist and then allowing time
for the soil to absorb the moisture, and repeating this several times, control
over particles being moved was believed to be quite satisfactory.
Perhaps in soil that does not accept mositure readily this procedure could be
improved by adding a wetting agent to the water; however, this was not necessary
in the areas in which the mound sampling studies were conducted.
Cross contamination from sampling equipment was prevented by decontaminating
This was done by using alcohol
the items used after each sample was taken.
and rinsing with water.
It was found that alcohol was needed to remove a
slight film that was left on sampling equipment from the soil having been
The items were then dried and a smear-type swipe was
mosit when sampled.
It was felt that
taken and counted on a scintillation alpha particle counter.
sample from
a
prevent
and
suffice
ion
would
this type of field decontaminat
tools.
sampling
to
due
contaminated
cross
being
It was imperative that the surface soil in the study area and sampling plots
not be disturbed any more than was absolutely necessary; therefore, vehicle
traffic was limited to existing roads only.
This meant that due to the few
roads in the study areas, most of the equipment used had to be carried a good
distance to and from the sampling locations by hand, thus entailing numerous
trips from the roadway where the vehicles were parked.
Boards 1" x 12" x 10' were used inside the sampling plots to walk on while
taking inventory, measuring, and sampling. Foot traffic to and from the
sampling plots was rerouted frequently to prevent the making of permanent
trails.
When surveying the plots for sampling, care was taken not to disturb the soil
or vegetation in these areas.
To determine the height of a mound or the desert pavement in relation to it,
the best method without having a crew of surveyors was to use a surveyor's
level (tripod-mounted type) and a grade stick.
This enabled the highest,
lowest, and midpoint heights to be easily taken.
Due to the large volume of soil in a mound caused by large animals such as
coyotes or badgers, a problem arose:
how to homogeneously mix and aliquot
such a large sample in the field.
After considering many ideas, the problem
was quite readily solved by using a cement mixer (approximately 1/4 cubic yard
in size).
It was determined that by mixing the soil for 15 minutes, a homogeneous mixture could be obtained.
From this an aliquot of approximately 5,000
grams was removed, sealed in a one-gallon can, and the remainder of the sample
was returned to the location from which it had been taken.
Some of these
samples were in excess of 200 pounds.
A medical scale with a capacity of 350
pounds was used for weighing the samples of large volume.
In order to prevent contaminating the mixer and to alleviate the possibility
of cross contaminating a sample, the mixer was lined with five 36" x 54" plastic
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