As found for the Fort Lewis range, RDX was
22
20
51
32
156
1.7
374
Tire 1
Tire 2
22
the explosives-related analyte found at high-
26
29
16
17
152
115
102
est concentration in the 27 surface soils that
50
12
518
193
12
4.6
were analyzed, although the concentrations
3.1
4.2
8.6
18
47
42
8.0
4.8
30
16
found at the Fort Richardson range were gen-
1.9
4.3
62
15
106
1.8
2.4
erally an order of magnitude lower than those
4.3
8.3
Wheel
15
79
39
found at Fort Lewis. The reason for this differ-
Samples
24
20
5.2
11
25
ence may be the practice at Fort Richardson of
4.3
4.3
filling in the craters with clean gravel after each
training session, or a lower usage of the range
in terms of total grenades thrown, than at the
20
Fort Lewis range. There were several RDX
concentrations in excess of 100 g/kg at the
Legend
Fort Richardson range, but the bulk of the val-
15
Surface
ues were below 30 g/kg, indicating that the
15 cm
30 cm
distribution of these data was also non-normal.
45 cm
Overall, RDX concentrations in the surface soil
10
Samples Collected
ranged from 1.7 to 518 g/kg with a median
value of 28.9 g/kg.
RDX was detected in all of the 21 subsoil
5m
RDX (g/kg)
samples collected at Fort Richardson as well,
Fort Richardson, AK
with concentrations ranging from 1.8 to 42.1
Hand Grenade Range
g/kg. Median values for soil samples collected
15
10
5m
at 15-, 30-, and 45-cm depths were 15.0, 5.2,
Pit
Pit
and 4.3 g/kg, respectively. These results
appear to indicate that RDX is leaching down-
Figure 11. Concentrations of RDX for soil samples collected
ward into the soil profile at the hand grenade
at the hand grenade range at Fort Richardson, Alaska.
range, but the concentrations leaching must be
8.5
6.8
7.2
29
30
0.85
134
Tire 1
Tire 2
very low. These residual concentrations in sub-
6.7
surface soils are often barely detectable, even
14
6.8
71
9.3
20
43
94
3.9
20
using the new GC-ECD method with much
52
3.4
1.5
2.5
<d
lower detection limits than the method that had
<d
<d
5.9
2.7
2.7
<d
<d
30
8.1
been used traditionally, RP-HPLC Method
<d
<d
9.7
<d
50
<d
<d
8330. Had method 8330 been used to analyze
<d
<d
Wheel
2.9
56
11
the soils samples at Fort Richardson, explo-
Samples
<d
<d
<d
0.71
25
sives analytes in most samples would have
<d
0.98
been non-detects.
The distribution of TNT concentrations in
20
surface soil samples at Fort Richardson was
found to be similar to that of RDX; several
values were above 50 g/kg, but the bulk of
Legend
the values was less than 20 g/kg (Fig. 12).
15
Surface
Here again, concentrations were an order of
15 cm
30 cm
magnitude or more lower than those found at
45 cm
Fort Lewis. In surface soil samples, TNT con-
10
Samples Collected
centrations ranged from 0.9 to 134 g/kg with
a median value of 9.7 g/kg. The two environ-
mental transformation products of TNT, 4-
5m
TNT (g/kg)
ADNT and 2-ADNT, ranged from <1 to 48.8
Fort Richardson, AK
g/kg and <1 to 28.0 g/kg, respectively, with
Hand Grenade Range
median values of 10.1 and 7.3 g/kg. Concen-
15
10
5m
trations of TNT in 16 of the 21 subsoil sam-
Pit
Pit
ples were <1 g/kg. Likewise, concentrations
of 4-ADNT and 2-ADNT were also generally
Figure 12. Concentrations of TNT for soil samples collected
<1 g/kg, indicating that neither TNT nor its
at the hand grenade range at Fort Richardson, Alaska.
15
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