concentrations under the mines may be increasing.
As usual, ERCs were most often detected near TMA-
A similar distribution of ERCs was found in sur-
5 and PMA-1A mines. ERCs were detected in 30% of
face soils near PMA-1A mines (Fig. 8). No ERCs were
the surface samples near TMA-5 mines. The analytes
detected directly above the mines, but ERCs were
detected most often for both types of mines continue to
often detected around their perimeters. Here, again,
be 2-ADNT, 4-ADNT, and 2,4-DNT; 2,4,6-TNT was
when ERCs were detected in a specific direction along
detected much more frequently in surface soils near
the edge of the mine, they were generally detected in
TMA-5 mines (22%) than near PMA-1A mines (6%).
samples collected 7 cm from the edge in that same
For surface soils collected over the perimeter of the
direction as well. The analytes present at highest con-
TMA-5 mines (Fig. 9), concentrations of 2-ADNT, 4-
centration were generally the 2-ADNT and 4-ADNT
ADNT, and 2,4-DNT were generally less than 100
g/kg, but occasionally concentrations above 100
transformation products, followed by 2,4-DNT and
g/kg were detected. Concentrations for 2,4,6-TNT
2,4,6-TNT. We did not specifically target 3-NA for the
were usually less than 10 g/kg. When ERCs were
July samples (using a specific RP-HPLC analysis) and
would, therefore, only have detected it if the concen-
detected above the perimeter of the mine, the same types
trations were relatively high because of its poor response
of ERC were often detected 7 cm away from the mine
on the ECD detector.
in the same direction. For surface samples collected
July 1999 was the first time samples were collected
directly above the mine, however, only 2,4,6-TNT was
near any of the second set of mines buried in April 1999.
generally detectable, but at very low concentrations (less
than 10 g/kg). No 2-ADNT or 4-ADNT was detected
Soil samples were collected near two Type 72 antitank
mines. ERCs were detected in 16 of the 70 soil samples,
in these samples collected directly above the mine.
but in only 2 of the 33 surface soils. This could be
For one TMA-5 mine (EX-261), surface samples
attributable to a combination of deeper burial for these
were also collected 20 cm off its corners (Fig. 9b). ERCs
mines and the shorter burial period (90 days). Unlike
were detected in three of these four samples. For two
the other two mine types, the analyte found most often
of these samples, the concentrations of 2-ADNT, 4-
for the Type 72 mines was 2,4,6-TNT, but the concen-
ADNT, 2,4,6-TNT, and 2,4-DNT were all less than 10
g/kg. In the other, the concentrations of 2-ADNT, 4-
trations were quite low. RDX was also detected at low
ADNT, and 2,4-DNT were 586, 685, and 248 g/kg,
concentrations in soil samples collected under these two
mines. This is reasonable, as RDX is a component of
respectively. These results indicate that ERCs are dif-
the main charge for Type 72 mines.
fusing away from the mines and the zone where they
can potentially be detected is considerably larger than
Soil samples collected in November 1999
the footprint of the mine itself. The fact that greater
In November 1999, 303 soil samples were collected.
concentrations of ERCs are found 7 and 20 cm away
Analytical results for these samples are presented in
from the mine, rather than directly over the mine, indi-
Appendix E. A summary of the explosives-related com-
cates that this diffusion must be occurring through the
pounds detected for each type of mine is presented in
subsurface soil, rather than the alternative, where the
Table 20.
signature penetrates the surface directly above the
Table 20. Frequency of detection of ERCs in soil samples collected near buried mines
in November 1999.
Number of detections
Soil
Total soil samples (surface samples**)
Mine
samples
type
collected*
2,4-DNT
2,4,6-TNT
1,3-DNB
2-ADNT
4-ADNT
RDX
PMA-1A
57 (36)
33 (14)
5 (2)
26 (9)
31 (14)
26 (11)
3 (1)
PMA-2
45 (26)
4 (0)
1 (0)
3 (0)
2 (0)
2 (0)
0 (0)
TMA-5
84 (46)
36 (13)
30 (10)
13 (1)
37 (14)
37 (14)
18 (5)
TMM-1
78 (42)
11 (0)
5 (2)
4 (1)
9 (1)
11 (1)
6 (0)
Type 72
39 (21)
3 (0)
3 (0)
0 (0)
4 (1)
5 (3)
5 (1)
*Numbers inside parenthesis in the Soil samples collected column refer to the number of surface soil
samples that were collected for a given mine type.
**Numbers inside parenthesis in the Number of detections columns refer to the number of surface soil
samples in which explosives related analytes were detected for a given mine type.
24
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