Table 1. Target concentrations for explosives in field-contaminated soil
mixtures.
Mass of
Target
Measured
Concentration*
Soil mass
explosives
concentration concentration
(g/g)
(g)
(g/g)
(g/g)
Soil
(g)
Clean soil
0
1,348.72
0
0
RDX soils
#9
1,800
9.52
17,130
#10
3,170
6.17
19,548
#11
12,200
6.83
83,383
RDX
22.52
120,061
80.35
85.81
TNT
12,200
10.13
123,586
82.71
77.99
Picric acid
1,000
112.88
112,880
75.54
120.26
Soil mixture
1,494.25
* Concentration of RDX soils from Walsh and Jenkins (1991). Concentration of TNT
soil and of picric acid soil from Jenkins et al. (1996).
Table 2. Target and measured concentrations for explo-
sives in aqueous solution.
Mass added
Target
Measured
to 4 L of water
concentration
concentration*
Explosive
(g)
(mg/L)
(mg/L)
40.81.7
RDX
0.2231
55.8
73.22.3
TNT
0.2939
73.5
78.15.0
Picric acid
0.4004
100.1
* Mean 1 standard deviation. Results of eight analyses
between days 38 and 95.
Inlet
Aqueous solution preparation
Outlet
An aqueous explosives solution was prepared by
Thermocouple
Soil
adding TNT, RDX, and picric acid to 4 L of Type I
Placement
Samples
S1
water. This solution was stored in a brown bottle to
reduce photodegradation of TNT. The solution was
T1
stirred for several days to ensure maximum dissolution
S2
of each component. Target and measured concentra-
Unfrozen Layer
tions of explosives in the aqueous solution are reported
(Contaminated)
in Table 2.
S3
T2
S4
Experimental chambers
T3
S5
The experimental setup (Boitnott et al. 1997) con-
sisted of four sealed cylindrical chambers made of Plexi-
S6
Frozen Layer
glas, 15.2 cm high and 7.6 cm in diameter, sitting on a
(Clean)
laboratory benchtop (Fig. 1). Insulated copper freezing
S7
coils surrounded the bottom half of each chamber; eth-
T4
ylene glycol from a constant temperature bath (15C)
was circulated through the coils to freeze the soil. Eth-
ylene glycol from a second temperature bath (10C)
S8
circulated through an additional copper coil resting on
top of the freezing coils to act as a transition zone for
Figure 1. Experimental chambers.
temperature change between the frozen and unfrozen
layers.
2
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