of the 172nd Separate Infantry Brigade and elements of the Arctic Support
Brigade within the Pacific theater, and worldwide as directed in support of
Pacific Command's (USARPAC) objectives, U.S. national interests, and
contingency operations. The fort encompasses 25,091 ha (62,000 acres), with
19,020 ha (47,000 acres) available for training. Military assets within that area
include a heliport, a drop zone suitable for airborne and air-land operations, firing
ranges, and other infantry training areas.
Sampling at Fort Richardson was limited to the hand grenade range that is
located in the small arms complex near Glenn Highway. The grenade range is not
divided into individual bays, but is a single open area with six launching bunkers
and a large rubber tire 35 m downrange of each to serve as a target. The surface
soil is mainly gravel. The top surface of the soil was frozen (20 October), but the
soil just beneath the surface was thawed at the time of collection. The area
between targets 1 and 2 was selected for sampling. No clues to the intensity of
use of each area were visible, since surface craters are filled in with gravel after
each exercise. However, the protocol for use of the range suggested that the six
areas were equally used.
At one sampling point a set of four soil samples was collected 27 m from a
line connecting the pits, or the launching points, and at depths of surface, 15, 30,
and 45 cm (Figure 6). A second set of four samples was taken at the same depths
and 27 m from the launch line, but 1 m to the left of the first set. Additional sets
of four samples were collected in an identical manner at distances of 30, 32 and
33 m from the launch line. A set of 15 surface soil samples 1 m apart was col-
lected at 35 m on the line between the two target tires (Figure 6). A seven-sample
wheel of surface soil samples, like that described for samples at Fort Lewis, was
centered at the 35-m line, 10 m left of tire 2 (Figure 6). At the center of the
wheel, three samples were collected at depths of 15, 30 and 45 cm. A total of
48 soil samples were collected at the Fort Richardson grenade range. Samples
were collected using shovels because of the gravelly consistency of the surface
soil.
Methods
Soil sampling and analysis
Shovels used for sampling at Fort Richardson were carefully wiped with
clean towels, washed with acetone, and air-dried between samples. Samples were
placed into precleaned, straight-walled jars. Each jar was sealed in a zip-lock bag
before shipping to the laboratory in ice-filled coolers (Federal Express,
overnight). Upon arrival at CRREL the samples were frozen at -30 C, and
extracted and analyzed within 2 weeks.
15
Chapter 2 Characterization of Explosives Contamination at Military Firing Ranges
Previous Page
