from the bottom of the crater. A total of 48 samples were collected within the
Fort Lewis hand grenade range impact area.
During sampling of the grenade range, evidence of several low-order
detonations was observed, where large portions of the grenade casings were
intact. These grenade casings were collected and returned to the laboratory for
explosives residue analysis.
Artillery range firing point
The day before and during the previous 6 weeks, National Guard units had
been firing eight 105-mm howitzers at Fort Lewis Range R74. Approximately
600 rounds had been fired through each of the howitzers prior to soil sampling.
The container in which the rounds had been stored was labeled as follows:
(Comp B, C445, M2A2, M 103, Cart 105, HEM1, dual grain with supply charge
85 percent nitrocellulose, 9 percent DNT, 5 percent dibutyl phthalate, and
1 percent diphenylamine. The area in front of two of the howitzers, Gun 1 and
Gun 2, was chosen for firing point sampling. Both guns were aimed approxi-
mately 200 deg true into the 91st Division Prairie Artillery Impact Area. The
firing area was grass covered with various shrubs and low trees. Dirt access roads
passed in front of the guns and were sampled when these were within the sam-
pling scheme. All surface soil samples included the top 0.5 cm as well as the
associated surface organic matter and shallow roots when present. One surface
soil sample was collected approximately 400 m to the east from the nearest gun
(Gun 1) to serve as an estimate of background contamination.
Gun 1. A measuring tape was laid out on the ground extending from the
front of Gun 1 and in the direction of fire. Surface soil samples (about 10 cm2)
were collected using a putty knife along the measuring tape at the following
distances from the muzzle: 0.5, 1.0, 1.5, 2.0, 2.5, 5.0 and 10.0 m (Figure 4).
Similar samples were collected perpendicular to the muzzle of the gun on both
sides at 1.5 and 3.0 m. Surface soil samples were also collected 3.0 m on both
sides perpendicular to the direction of fire at 5.0 m and 10.0 m. The final soil
sampling, 2 m in front of the muzzle, took place as follows. A wheel-shaped
1.2-m-diameter sheet of plastic was placed on the ground. Six equally spaced
surface soil samples were collected around the circle, and one surface soil sample
was collected in the middle of the circle. Additionally, two depth samples, 0-
5 cm and 5-9 cm, were collected in the center of the circle. This sampling scheme
produced a total of 22 surface and 2 different depth soil samples at Gun 1
(Figure 4).
Gun 2. A measuring tape was laid out on the ground in front of Gun 2 and in
the direction of fire. Surface soil samples were collected using a putty knife along
the measuring tape at the following distances from the muzzle: 0.5, 1.0, 1.5, 2.0,
1
HOW probably indicates "howitzer."
12
Chapter 2 Characterization of Explosives Contamination at Military Firing Ranges
Previous Page
