3.7
57
5.3
30
27
<d
32
Tire 1
Tire 2
2.8
7.3
80
3.4
9.5
5.4
67
56
6.9
2.7
37
2.0
3.8
<d
<d
<d
<d
4.6
9.7
<d
<d
<d
30
5.6
<d
<d
6.0
1.1
12
<d
<d
<d
<d
Wheel
2.6
10
5.4
Samples
1.8
3.3
<d
2.2
25
<d
1.8
Figure 13. Concentrations of HMX for soil samples
collected at the hand grenade range at Fort Rich-
20
ardson, Alaska.
Legend
15
Surface
15 cm
30 cm
45 cm
10
Samples Collected
5m
HMX (g/kg)
Fort Richardson, AK
Hand Grenade Range
15
10
5m
Pit
Pit
from the artillery firing point for Howitzer #1 and How-
daughter products were leaching at detectable concen-
itzer #2 are presented in Tables 6 and 7, respectively. In
trations below the surface soil. The behavior of TNT
both cases, the major propellant-related compounds
relative to RDX is not surprising since TNT and its
observed were the various isomers of dinitrotoluene
daughter products are known to sorb to soils to a much
(2,4-DNT, 2,6-DNT, 2,5-DNT, and 3,4-DNT), the two
greater extent than RDX (Brannon et al. 1999).
isomeric environmental transformation products of 2,4-
Concentrations of HMX in surface soils at Fort Rich-
ardson ranged from <1 to 80.4 g/kg with a median
DNT, 4-amino-2-nitrotoluene (4A2NT) and 2-amino-
value of 6.9 g/kg (Fig. 13). A ratio of the median val-
4-nitrotoluene (2A4NT), and 2,4,6-TNT. The presence
of 2,4,6-TNT at the firing point was unexpected, and
ues for RDX/HMX in these soils is 4.2 compared with
we assume it is a manufacturing impurity in dinitrotol-
a mean ratio of 7.6 for the Composition B extracted
uene. Of these compounds, 2,4-DNT was present at the
from a low-order hand grenade. Concentrations of HMX
in the subsoil were found to be <1 g/kg in 14 of the 21
highest concentration in all samples from both guns.
Concentrations of 2,4-DNT varied from 982 to 175,000
samples analyzed. The lower solubility and rate of dis-
g/kg (median value = 31,500) for surface samples
solution of HMX compared with RDX is probably
collected in front of Howitzer #1 and from 1030 to
responsible for a lower residual concentration ratio of
237,000 g/kg (median value = 40,900) in front of
RDX to HMX in surface soil than is present in Compo-
Howitzer #2. While these numbers appear quite large,
sition B, and for the higher ratio of RDX to HMX found
it must be remembered that the units are g/kg or parts
in the subsoil samples.
per billion, and the guns had fired about 600 rounds
Overall, subsurface concentrations of these explo-
from the same position over several months before we
sives-related analytes decline rapidly below the surface
sampled.
soil at Fort Richardson. Because this grenade range has
The propellant-related compounds detected at the
a much harder surface than that at Fort Lewis, we
next highest concentrations were 4A2NT and 2A4NT
believe there is much less mixing of the soil profile and
(Table 7). These two compounds ranged in concentra-
analytes found at depth were more likely to have arrived
tion for surface soil from <d to 3,000 g/kg and from
by leaching than for the subsurface samples we col-
<d to 1,340, respectively. They were generally present
lected at Fort Lewis.
in the surface soil at about two orders of magnitude
lower concentration than 2,4-DNT. Concentrations of
Artillery range firing point
2,6-DNT, 3,4-DNT, and 2,4,6-TNT were also found to
Results from analysis of the 47 surface soil samples
16
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