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Guide for Characterization of Sites Contaminated with Energetic Materials
11
decisions with respect to human safety and liability. This is particularly true
when explosives are the targeted contaminants. Reliable field methods can reduce
the unique hazards involved with manipulating, transporting, and storing samples
that contain explosives. Furthermore, distribution of analyte concentrations can
be assessed on site in real time, thereby decreasing the total number of samples
needed to characterize a site. Nevertheless, laboratory-based instrumentation
generally provides more precise and accurate analytical data than most field
methods. Thus, samples that demonstrate a positive response in a field test should
then be tested with an approved laboratory method for increased precision.
Table 2. Detection limits for explosives in soil (mg/kg).
Compound
HPLC
GC-ECD
GC-TID
0.027
0.025
1
HMX
0.0094
0.0034
1
RDX
0.0024
0.0016
0.3
Trinitrobenzene (TNB)
0.012
0.00073
0.3
Dinitrobenzene (DNB)
0.0017
0.020
0.7
Tetryl
NA*
0.017
0.3
Nitrobenzene (NB)
0.0016
0.0013
0.3
1,4,6-trinitrotoluene (TNT)
0.0068
0.002
0.3
2-amino-4,6-dinitrotoluene (2-ADNT)
0.0010
0.0015
0.3
4-amino-2,6-dinitrotoluene (4-ADNT)
0.0054
0.00069
0.3
2,6-diamino-4-nitrotoluene (2,6-DANT)
0.0016
0.00068
0.3
2,4-diamino-6-nitrotoluene (2,4-DANT)
NA
0.012
0.3
2-nitrotoluene (2-NT)
NA
0.011
0.3
3-nitrotoluene (3-NT)
NA
0.010
0.3
4-nitrotoluene (4-NT)
*NA Not available
In summary, field screening methods are generally used to
Establish safety levels for the manipulation of potentially contaminated
samples in relation to the 10% threshold safety limit--colorimetric test
or GC method recommended (Appendixes H and I).
Screen soil or water samples for the absence/presence of explosive com-
pounds before they are sent to the laboratory for quantitative analysis.
Optimize the efficiency of sampling required to delineate the area and
depth of contamination of both the soil and groundwater.
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