that land-mine-derived analytes were detectable in the
Table 3. Mean flux (ng/mine-day) into air for
soil near PMA-1A and TMA-5 mines two months after
1,3-DNB, 2,4-DNT, and 2,4,6-TNT from PMA-1A,
burial. Importantly, 2,4-DNT, 2,4,6-TNT, and 1,3-DNB
PMA-2, TMA-5, and TMM-1 land mines at tem-
were detected in soil taken from the surface above these
peratures ranging from 3 to 34C. (From
two types of land mines. Additionally, Walsh and
George et al. 1999.)
Ranney (1999) reported the presence of 2-amino-4,6-
dinitrotoluene (2ADNT) and 4-amino-2,6-dinitro-
Temp
toluene (4ADNT) in these surface soils; these com-
(C)
1,3-DNB
2,4-DNT
2,4,6-TNT
pounds are environmental transformation products of
PMA-1A
2,4,6-TNT (McCormick et al. 1976).
3
1410
468
22.9
That amino transformation products are present in
13
1950
741
75.9
the soil shows us the importance of understanding the
22.5
4680
912
229
stability of land-mine-derived signature chemicals in
23
8710
3390
347
soil. The stability issue has been studied by Maskarinec
34
14100
6170
832
et al. (1991) and Grant et al. (1993, 1995). Both
TMA-5
reported data on the stability of 2,4,6-TNT and 2,4-DNT
3
437
1660
219
in moist soil samples held at several temperatures for
13
1510
6310
437
periods up to a year. Both studies report that 2,4-DNT
22.5
4680
20000
1660
is more stable in fortified soil than 2,4,6-TNT. The half-
23
6460
28800
1580
34
14500
67600
8710
life for 2,4,6-TNT was less than 3 days for the six for-
tified soils at room temperature (about 22C), three stud-
PMA-2
ied by Grant et al. (1993) and three by Maskarinec et
3
40.7
32.3
2.5
al. (1991). But, half-lives increased to greater than 14
13
138
115
8.5
days for four of the six soils held at 4C. When air-
22.5
389
316
28.2
23
562
490
49.0
dried soils were fortified with 2,4,6-TNT and 2,4-DNT
and held at 4C for 62 days, however, there was no
34
1820
1620
97.7
evidence of any loss of either analyte (Bauer et al. 1989).
TMM-1
These results tell us how important soil moisture is for
3
40.7
182
105
facilitating biotransformation of these analytes, presum-
13
129
724
302
22.5
380
2190
1050
ably by microorganisms.
23
398
2290
851
Recently, Miyares and Jenkins (in press) reported
34
1150
7590
4570
results of experiments where several components of
ERCs (2,4,6-TNT, 2,4-DNT, 1,3-DNB, 2,6-DNT, and
RDX) were spiked into moist soil from Fort Leonard
Wood at concentrations of about 500 g/kg and held at
face contamination (Table 2) in concert with the much
either 22, 4, or 4C for periods up to 30 days (Table
higher flux rate into water (Leggett et al., in prep.). For
mines that are not completely sealed, an additional
5). The results indicated that the concentrations of 2,4,6-
mechanism may be direct dissolution of ERCs by
TNT and 1,3-DNB declined more rapidly than did the
water contacting the explosive.
concentrations of 2,4- and 2,6-DNT. For 2,4,6-TNT, the
Other than our work, only a few measurements of
concentration declined to about half of its initial value
the concentrations of ERCs in soil near buried mines
in only about a day (Table 5) when the soil was held at
room temperature (22 2C). Under the same storage
have been reported. Chambers et al. (1998) reported
that concentrations of 2,4-DNT and 2,4,6-TNT ranged
conditions, the concentration of 2,4-DNT had yet to be
from 10 to 2700 g/kg and 20 to 2000 g/kg, respec-
reduced to half its initial value even after 20 days of
tively, in soils taken near a TMA-4 mine, 150 days
storage. These results were quite similar to those
after burial. Desilets et al. (1998) reported that the con-
reported by Maskarinec et al. (1991) and Grant et al.
centration of 2,4,6-TNT was about 0.008 g/kg in soil
(1993) for the six soils they studied.
10 months (300 days) after burial of a TMA-4 land mine.
The stability of residues in surface soils that were
Walsh and Ranney (1999), during the development of
contaminated by nearby detonations of land mines
a low-level method for determining explosives residues
(Phelan et al., in press) was recently investigated by
in soil, reported concentrations of land-mine-derived
Sandia National Laboratories. The results indicate that
signatures in 23% of the soil samples collected near
the rate of degradation depends on biochemical degra-
TMA-5, PMA-1A, and PMA-2 mines, two months (48
dation rates, which in turn depend on temperature and
days) after burial (Table 4). These results demonstrated
moisture content.
3
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