TMA-5 (EX-265)
September 1998
Surface Soil
Height= 113 mm
N
W
E
4
30
S
DNT
312 mm
TNT
Am-DNT
29
4 160
Figure 3. Locations of various ERCs detected in surface soil near buried
TMA-5 land mine EX-265 in August 1998.
detected in surface soils near TMA-5 mine EX-265 are
areas with buried PMA-2 land mines, and that soil was
shown in Figure 3.
in direct contact with the mine. No ERCs were detected
The distributions of ERCs in soils about the TMA-
in any of the soil samples collected near TMM1 mines.
5 mines appears to be quite heterogeneous. For TMA-
Overall, the results from analysis of these initial soil
5 mine EX-264, ERCs were detected in soil samples
samples tell us that ERCs were accumulating in the soil
collected on the east side of the mine, but not from the
near some of the mines, particularly some of the TMA-
north, south, or west sides. For mine EX-265, ERCs
5 and PMA-1A mines. Of the major ERC components
were detected in soils on the east and south sides, but
(2,4-DNT, 1,3-DNB, and 2,4,6-TNT) detected on mine
not the north. For mine EX-292, ERCs were detected
surfaces (Leggett et al. 2000), and in mine flux (George
in soils on the east and south sides, but not on the west.
et al. 1999), 2,4-DNT appears to be accumulating to
For mines EX-253 and EX-267, no ERCs were detected
the greatest extent in soil near the buried mines. 2,4,6-
in any of the soil samples analyzed, even though
TNT, on the other hand, appears to be transforming rap-
samples were collected from all four sides of these
idly in the soil to 2-ADNT and 4-ADNT, these two
mines. This is not to suggest that we expect the ERCs
transformation products often being present at the high-
to have a distribution based on geomagnetic orienta-
est concentration in soil for any of the ERCs. This
tion. But, rather, we believe that the heterogeneous
result agrees with the relative environmental stability
nature of the mine signature is a result of the local
of 2,4,6-TNT and 2,4-DNT that was determined in soil
microenvironment unique to each mine location. The
stability tests (Maskarinec et al. 1991, Grant et al. 1993,
detection of ERCs in a given sample may be related to
Miyares and Jenkins, in press). 1,3-DNB was detected
whether or not we fortuitously selected an area where
less often than 2,4-DNT (and at lower concentration)
they had accumulated.
in these soil samples as well, and never in any of the
ERCs were detected in 4 of the 20 soil samples col-
surface soils. It is also less stable than 2,4-DNT in soil
lected near PMA-1A mines (20%). Qualitatively, the
(Miyares and Jenkins, in press), and may be transform-
chemicals detected in the subsurface soil samples were
ing to 3-nitroaniline (3-NA). We did not specifically
2,4-DNT, 2-ADNT, 4-ADNT, 2,4,6-TNT, 1,3-DNB, and
target 3-NA in this first set of soil analyses and, hence,
2,6-DNT. The highest concentrations observed were
we cannot comment on its presence or absence in these
much lower than those found near the TMA-5 mines;
samples.
for 2,4-DNT the maximum concentration was 77 g/kg,
The lack of more significant concentrations of ERCs
for 2-ADNT it was 314 g/kg, for 4-ADNT it was 317
in the surface soils observed may be ascribable to lim-
g/kg, for 1,3-DNB it was 32 g/kg, and for 2,4,6-TNT
ited mobility of these compounds under the drought
it was only 1.5 g/kg. ERCs (2-ADNT and 4-ADNT)
conditions that predominated since the mines were bur-
were only detected in one surface soil sample collected
ied. Laboratory studies and current knowledge of the
near PMA-1A mines.
behavior of ERCs in a soil matrix indicate that the
ERCs were detected in only one soil sample from
major pathways for explosives migration to the surface
15
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