ples collected in the wheel pattern, where only surface
itzers prior to our collecting the soil samples. The rounds
samples were collected. All soil samples were collected
being fired had the following information on their stor-
using stainless-steel trowels that were carefully wiped
age container: (Comp B, C445, M2A2, M 103, Cart
with a clean paper towel, washed with acetone, and air-
105, HEM1, dual grain with supply charge without fuse
dried between samples. About 50 g of soil was collected
for HOW). The propellant being used for these rounds
for each sample.
is composed of 85% nitrocellulose, 9% dinitrotoluene,
We noticed a deep (approximately 93 cm) crater
5% dibutylphthalate, and 1% diphenylamine. The area
approximately 30 m from the launch bunker, its depth
in front of two of the howitzers (referred to as Howit-
possibly the result of multiple impacts or EOD activity.
zer #1 and Howitzer #2) was chosen for firing point
The bottom of the crater appeared to represent undis-
sampling. Both howitzers were aimed approximately
200 true into the 91st Division Prairie Artillery Impact
turbed native subsoil, its finer grain being much differ-
ent from the overlying gravel. A surface sample was
Area. The firing area was grass-covered with various
collected at the bottom of the crater and then at 10-, 15-,
shrubs and low trees. Dirt access roads passed in front
23-, and 30-cm depths below surface. We were careful
of the guns and were sampled when within the sampling
to remove the overlying soil and then collect the sam-
scheme. All surface soil samples collected included the
ples at the discrete depths indicated. It was noted that
top 0.5 cm of soil as well as the associated surface organic
the samples taken from the bottom of this crater were
matter and shallow roots when this material was present.
moist whereas the surface samples were quite dry.
One surface soil sample was collected approximately
The most distant crater from the launch area, at
400 m to the east from the nearest gun (Howitzer #1) to
approximately 45 m, was selected for sampling to rep-
serve as an estimate of background contamination
resent the effect of minimal range use. One composite
within the area from other firing events.
surface soil sample was collected from the rim of the
crater, one surface sample at the bottom of the crater,
Howitzer #1
and a discrete depth (10 cm) sample was collected from
A measuring tape was placed on the ground extend-
the bottom of the crater. A total of 48 samples was col-
ing from the front of Howitzer #1 in the direction of
lected within the Fort Lewis hand grenade range impact
fire. Using a putty knife, surface soil samples (about
10 cm2) were collected along the measuring tape at the
area.
While sampling the grenade range, we observed what
following distances from the muzzle: 0.5, 1.0, 1.5, 2.0,
appeared to be evidence of several low-order detona-
2.5, 5.0, and 10.0 m (Fig. 3). Similar samples were also
tions, where large portions of the grenade case were
collected on both sides perpendicular to the muzzle of
still intact. These grenade casings were collected and
the howitzer at distances of 1.5 and 3.0 m. Surface soil
returned to our laboratory for analysis.
Gun Orientation
Artillery range firing point
4
2
0
2
4m
The day before we were scheduled to sample the
0m
artillery range impact area at Fort Lewis, the active artil-
lery firing area at Fort Lewis (R74) was being used by
National Guard units for 105-mm howitzer practice.
The various units had eight howitzers set up and had
2
been firing for six weeks. Approximately 600 of the
105-mm rounds had been fired through each of the how-
4
6
8
Samples Collected
Gun #1
105-mm Howitzer
10
Figure 3. Surface soil samples collected at firing point in front of the muzzle
of 105-mm Howitzer #1.
5
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