Characterizing Range Scrap and
Developing Quality Assurance Coupons
for Hot Gas Decontamination Trials
ALAN D. HEWITT
INTRODUCTION
(4AmDNT). We can see that several explosives are
The Army is currently evaluating hot gas treatment
likely to be associated with range scrap; however, sev-
as an environmentally acceptable way to decontami-
eral of these (2,4-DNT, 2,6-DNT, TNB, DNB,
nate the metallic debris that result from military train-
2AmDNT, and 4AmDNT) are either impurities or
ing and testing. Residues of explosives degrade when
break-down products of TNT, RDX, and HMX. We
they are exposed to moderate temperatures (500600F,
anticipate that these energetic residues will be extremely
260316C); therefore, a low-cost hot gas decontami-
heterogeneous on range scrap. Therefore, a simple
nation (HGD) system has been proposed as an economi-
screening test would help to establish their presence
cal way to remediate the metallic debris to the 5 clean
and to control the number of samples that would have
up standard (Parsons 1998). So that the off-gas stream
undetectable concentrations of explosives.
from this treatment process does not need treatment it-
Currently, there are no standardized protocols for
self, the range scrap should be mainly metallic debris;
assessing energetic residues on the surfaces of range
that is, it should be free of large pieces of plastic or
scrap. However, there are documented procedures for
rubber. To optimize and validate the effectiveness of
wiping relatively smooth surfaces to quantitatively as-
the HGD technology, on-site analytical methods to char-
sess lead in dust (ASTM 1999). Metallic range scrap is
acterize energetic residues on range scrap and proto-
composed of a wide variety of objects of irregular shapes
cols for quality assurance (QA) samples are needed.
and sizes that often have rough (pitted), highly oxidized
The presence of energetic residues on range scrap
surfaces. In addition, there can be deep crevices, folded
has been reported by Jenkins et al. (1997). In their study,
joints, and partly enclosed cavities. When the data qual-
they immersed a 7-g piece of metallic debris from a
ity objective is to identify the presence and type of explo-
LAW rocket in acetone to extract surface residues. This
sive residues, sampling procedures similar to those de-
experiment established the presence of octahydro-
veloped for collecting lead in dust can be used, coupled
1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2, 4,
with a single step or tiered analysis protocol.
6-trinitrotoluene (TNT) from the octol that was used as
Inexpensive on-site colorimetric and enzyme immu-
the main charge in the LAW rocket. Walsh et al. (1993)
noassay detection methods exist for both TNT and RDX
pointed to other explosives that are likely to be present
(Crockett et al. 1997). Colorimetric-based methods also
at sites contaminated with army munitions. Their study,
exist for 2,4-DNT (Jenkins and Walsh 1992) and am-
which compiled data from several sites where soil
monium picrate (Thorne and Jenkins 1995), and the
samples had been analyzed by Method 8330, established
RDX colorimetric method can be used to estimate HMX
the following order from the most to least frequently
concentrations, when this explosive is present at con-
detected explosives: TNT, 2,4-dinitrotoluene (2,4-
centrations several orders of magnitude higher than
DNT), 1,3,5-trinitrobenzene (TNB), 1,3,5-hexahydro-
RDX (Jenkins et al. 1998). The RDX colorimetric pro-
1,3,5-trinitrotriazine (RDX), 1,3-dinitrobenzene (DNB),
cedure will also detect nitrate esters (nitrocellulose
2-amino-4,6-dinitrotoluene (2AmDNT), HMX, methyl-
[NC], nitroglycerin [NG], and pentaerythritol
2,4,6-trintrophenylnitramine (Tetryl), 2,6-dintrotoluene
tetranitrate [PETN]) when they are present in high con-
(2,6-DNT), and 4-amino-2,6-dinitrotoluene
centrations (Crockett et al. 1997). Because these colo-
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