future, for both safety and accuracy concerns. These
the test pad there were nitrocellulose propellant rods (2
in. [5.1 cm] long 0.75 in. [1.9 cm] diameter) scat-
problems, most likely, can be avoided by purchasing
commercial stock standards and storing them in a
tered over the general area.
freezer. Concentrated standards of TNT (50.0 mg/mL
A colorimetric screening test was used during this
in acetone), RDX (20.0 mg/mL in a mixture of
site visit to help determine which pieces of range scrap
MEK:methanol:acetone), and HMX (20.0 mg/mL in
and other materials should be sampled for off-site labo-
methanol) are available from AccuStandard Inc. (New
ratory analysis. Several positive colorimetric results
Haven, Connecticut).
were obtained at the first location, and a couple were
obtained at the ARL test pad. All of the pieces of range
scrap that responded positively to the colorimetric
A field-transportable SRI Model 8610C gas chro-
screening test were sampled for off-site analysis, along
matograph, equipped with a heated (250C) TID de-
with pieces of material that were likely to retain (sorb)
tector selective for nitro groups, a heated (225C) on-
explosive signatures. In all 37 samples were taken for
column injection port, and an internal air compressor,
off-site analysis. The majority of these samples were
was used for this study. Separations were performed
wipes, which were obtained using a small-diameter (1.5
on a Crossbond 100% dimethyl polysiloxane column,
cm) filter paper that had been soaked in methanol. These
15 m 0.53 mm i.d., 1.5 m (DB-1), using the follow-
wipes were placed on the surfaces of the range scrap.
ing temperature program: 145C for 0.5 minutes, ramp
After drying, they were folded and placed in a 2-mL
to 150C at 5C/min, ramp from 150 to 250C at
amber vial. Other types of samples taken during this
20C/min, hold at 250C for 0.5 minutes. The TID cur-
initial visit were pieces of rubber/plastic gaskets, waxy
rent was set at 3.40 V and the carrier gas was supplied
substances, and soil (debris particles) collected from
from an auxiliary nitrogen cylinder. The carrier gas
the bottom of the scrap bins. Appendix A gives a brief
was set at 15 psi (103.4 kPa) for a column flow of 37.5
description of each of these samples.
mL/min. The on-board air compressor was set at 5 psi
The colorimetric tests used to screen for explosive
(34.5 kPa) to supply gas to the detector at 25 mL/min.
residues on-site were done using the Expray kit (Mis-
Injections of 1 L were made manually with a 10-L
tral Security, Inc.; available from Plexus Scientific, Sil-
glass syringe (SGE) equipped with a 7.0-cm-long
ver Spring, Maryland). These tests use reagents that
needle. Under these conditions, detection limits for
identify explosives on the basis of Janowsky and Griess
TNT, RDX, and HMX are expected to be about 0.01,
reactions. The Expray kit comes in a small, lightweight
0.5, and 5.0 g/mL, respectively.
(less than 1.4 kg) case that contains three aerosol cans
for dispensing chemical reagents and some paper for
wiping surfaces. To screen range scrap, the first step
EXPERIMENTS
was to wipe (rub) exposed surfaces with a white sheet
of paper (100 test sheets are supplied with the kit, or
Site visit
any white filter paper could be used). For sampling soils
The Aberdeen Test Center (ATC) was visited on 1
or other fine particles, a small quantity (0.5 to 1 g) was
and 2 May 2000 to establish which explosives com-
placed in the middle of 47-mm pieces of glass fiber
pounds were most prevalent on range scrap there. In
filter paper, then soaked with acetone (approximately
all, three different locations were visited. The first was
twice the volume as weight). Then the filter paper was
a light armor test range. Here, range scrap had been
folded over and placed on a clean white surface. Next,
collected and placed in a large metal bin, which con-
the surface of the wipe or folded filter paper was
tained pieces of an RDX material and some metal de-
sprayed, in accordance with the kit instructions. If a
bris with surface smears of RDX. The second location,
color appears after the first aerosol is applied, then
Dump 3, had wooden crates containing 155- and 175-
polynitroaromatics (e.g., TNT, TNB, DNT, Picric acid,
mm rounds that had been cut open. Most of these rounds
tetryl, etc.) are present. Some of the colors that may
had been buried in damp soil for about 20 years before
appear after this first aerosol is applied are blue, red, or
they were collected and prepared for disposal, and were
orange. After the second aerosol is sprayed, the forma-
heavily corroded (oxidized). The third area consisted
tion of a pink color indicates the presence of nitramines
of two locations on the grounds of the Army Research
or nitrate esters (e.g., RDX, HMX, NG, PETN, NC,
Laboratory (ARL). At the first location there were large
NQ, and tetryl, etc.). Next, the sample is sprayed with
witness plates that had been cleared for scrap metal re-
the third aerosol. If a pink color appears only after ap-
cycling inside a secured compound. The second loca-
plying the third aerosol, then the presence of an inor-
tion was a test pad with a wide variety of materials that
ganic nitrate (ammonium, potassium, sodium, barium,
had been partly segregated into metal bins and piles. At
strontium nitrate, or black powder) is indicated. This
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