5,000
RTX-5
Sample #78
4,000
3,000
2,000
1,000
0
5
7
9
11
13
15
3
17
Time (min.)
Figure 19. GC-ECD chromatogram of soil extract from surface soil sample collected at crater formed by
the detonation of a 105-mm howitzer round
nine samples at concentrations ranging from 1.2 to 21.0 :g kg-1. Each of the two
transformation products of TNT, 4ADNT and 2ADNT, was found in eight of the
nine samples at concentrations ranging from 5.4 to 20.6 :g kg-1and 2.6 to 15.2 :g
kg-1, respectively. The 2,4DNT was detected in only two samples at
concentrations of 7.3 and 9.9 :g kg-1.
The discovery of RDX and TNT in a number of these samples was not
surprising since the 105-mm rounds contain Composition B as the main charge.
The fact that 4ADNT and 2ADNT were found at concentrations generally as high
as that of TNT was unexpected, since the detonation forming this crater probably
occurred only the previous day. The rapid formation of these transformation
products from TNT, however, is consistent with the half-lives observed for TNT
in a recent report by Miyares and Jenkins (2000) and some earlier work by
Maskarinec et al. (1991) and Grant, Jenkins, and Golden (1993).
The fifth area was a 155-mm crater several years old judging by the
vegetation cover. Nine samples were collected in and around this crater, two
composites from within the crater and a seven-sample wheel centered on the
crater as described previously (Table 7, samples 88-96). No explosives-related
analytes were observed for the three samples collected within the crater, but
RDX, 4ADNT, and 2ADNT were detected in all six of the samples collected
40
Chapter 2 Characterization of Explosives Contamination at Military Firing Ranges
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