though it was detected in a number of subsurface
A set of 13 PMA-1A surface samples that had been
samples at concentrations generally under 100 g/kg.
identified with ERCs by GC-ECD was selected for
For the PMA-1A mines, 39% of the surface samples
HPLC analysis to determine the presence or absence
had detectable levels of 2-ADNT, 4-ADNT, or 2,4-DNT,
of 3-NA. These HPLC analyses show that 3-NA is
with maximum concentrations of 600, 459, and 227
detectable in nearly every sample; however, we were
g/kg, respectively. When detectable, concentrations
unable to confirm the identity using a second HPLC
of these three analytes in surface soils were often near
column. At present, we are attempting to confirm the
50 g/kg. 2,4,6-TNT was only detected in two surface
presence of 3-NA in these samples using GC-NPD
samples and then only at a maximum concentration of
(nitrogen phosphorus detector).
4 g/kg (Fig. 10).
Of the 45 soil samples collected near the small PMA-
ERCs were detected in half of the surface samples
2 mines, only four had detectable ERCs. No ERCs were
collected 7 cm from the edges of both of the PMA-1A
detected in any of the 26 surface samples. Even for soil
mines that were sampled. For one of these mines, sur-
samples collected directly under the mines, the con-
face soils were also collected at distances of 20 cm off
centrations of ERCs were low; the highest concentra-
tion was for 2,4-DNT (70 g/kg). No 2,4,6-TNT was
the four corners of the mine (Fig. 10). ERCs were only
detectable in one of these samples. Once again, the sur-
detected in these samples. Similarly, ERCs were
face area where signatures are available for detection
detected in 11 of the 78 soils samples collected near
appears to be greater than the footprint of the mine.
the metallic-cased TMM-1 mines, but ERCs were
Compared to TMA-5s, the frequency of detection
detected in only 2 of the 42 surface soils. Clearly, it
of 1,3-DNB was much greater for soils collected near
will be very difficult to detect TMM-1 and PMA-2
the PMA-1A mines. Concentrations of 1,3-DNB were
mines using chemical detection, compared to the PMA-
often one-half to one-third that found for 2,4-DNT. The
1A and TMA-5 mines, where ERCs are much more
greater detection of 1,3-DNB in soils near the PMA-
prevalent in the surface soils.
1A mines is consistent with the higher surface concen-
Only 10 of the 39 soil samples collected near the
tration (Table 2) and flux (Table 3) of 1,3-DNB for this
one Type 72 antitank mine that we sampled had detect-
mine relative to the other types of mines studied.
able levels of ERCs. 2,4,6-TNT and 2,4-DNT were only
10
86
4 428
Height= 3.1 cm
72
10
327
4
2
7.0 cm
14.4 cm
227
1060
6
157
6 540
7
71
6
9
6 235
N
DNT
PMA-1A (EX-048)
W
E
November 1999
TNT
Am-DNT
Surface Soil
S
Jenkins-028
Figure 10. Locations of various ERCs detected in surface soil near buried PMA-1A
land mine EX-048 in November 1999.
26
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