DTIC ADA579893: TNT Particle Size Distributions From Detonated 155-mm Howitzer Rounds

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by  Defense Technical Information Center

Chemosphere55(2004)357–367
www.elsevier.com/locate/chemosphere
TNT particle size distributions from detonated
155-mm howitzer rounds
Susan Taylor a,*, Alan Hewitt a, James Lever a, Charlotte Hayes b,
Laura Perovich a, Phil Thorne c, Chuck Daghlian d
aColdRegionsResearch&Eng.Lab.,CRREL,DepartmentoftheArmyCorpsofEngineers,
EngineerResearchandDevelopmentCenter,72LymeRoad,Hanover,NH03766-1290,USA
bEngineerResearchandDevelopmentCenter,WES,Vicksburg,MS,USA
cAppliedResearchAssociates,415WatermanRoad,SouthRoyalton,VT05068,USA
dDartmouthCollege,Hanover,NH,USA
Received12May2003;receivedinrevisedform31October2003;accepted10November2003
Abstract
Toachievesustainablerangemanagementandavoidorminimizeenvironmentalcontamination,theArmyneedsto
know the amount of explosives deposited on ranges from different munitions and how theseare degraded and trans-
portedunderdifferentgeologicalandclimaticconditions.Thephysicalformofthedepositedexplosiveshasabearing
on this problem, yet the shapes and size distributions of the explosive particles remaining after detonations are not
known.
Wecollectedresiduesfrom8high-orderand6low-ordernon-tacticaldetonationsofTNT-filled155-mmrounds.We
foundsignificantvariationintheamountofTNTscatteredfromthehigh-orderdetonations,rangingfrom0.00001to
2% of the TNT in the original shell. All low-order detonations scattered percent-level amounts of TNT. We imaged
thousandsofTNTparticlesanddeterminedthesize,massandsurface-areadistributionsofparticlescollectedfromone
high-orderandonelow-orderdetonation.Forthehigh-orderdetonation,particlessmallerthan1mmcontributemost
ofthemassandsurfaceareaoftheTNTscattered.Forthelow-orderdetonation,mostofthescatteredTNTmasswas
intheformofun-heated,centimeter-sizedpieceswhereasmostofthesurfaceareawasagainfromparticlessmallerthan
1mm.WealsoobservedthatthelargepiecesofTNTdisintegratereadily,givingrisetomanysmallerparticlesthatcan
quickly dissolve. We suggest picking up the large pieces of TNT before they disintegrate to become point sources of
contamination.
(cid:1) 2003Elsevier Ltd. All rightsreserved.
Keywords:Blow-in-placedetonations;TNTparticles;SEM;Sizedistribution;Surfacearea;Massrecovered
1.Introduction
Firing ranges provide soldiers the opportunity to
trainusingavarietyofmunitions.However, asaresult
of training, unexploded ordnance (UXO), low-order
*Correspondingauthor.Tel.:[phone];fax:+1-603- detonations(whereasignificantfractionoftheexplosive
646-4785. remains un-detonated) and the explosive residues from
E-mail address: [email protected] (S. Tay- live fire detonations may contaminate the soil and the
lor). groundwater,andconsequentlyposeenvironmentaland
0045-6535/$-seefrontmatter (cid:1) 2003ElsevierLtd.Allrightsreserved.
doi:10.1016/j.chemosphere.2003.11.031
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1. REPORT DATE 3. DATES COVERED
2003 2. REPORT TYPE 00-00-2003 to 00-00-2003
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
TNT Particle Size Distributions From Detonated 155-mm Howitzer
5b. GRANT NUMBER
Rounds
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
Cold Regions Research & Eng. Lab,Engineer Research and Development REPORT NUMBER
Center,72 Lyme Road,Hanover,NH,03766
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)
11. SPONSOR/MONITOR’S REPORT
NUMBER(S)
12. DISTRIBUTION/AVAILABILITY STATEMENT
Approved for public release; distribution unlimited
13. SUPPLEMENTARY NOTES
Chemosphere 55 (2004) 357-367
14. ABSTRACT
To achieve sustainable range management and avoid or minimize environmental contamination, the Army
needs to know the amount of explosives deposited on ranges from different munitions and how these are
degraded and transported under different geological and climatic conditions. The physical form of the
deposited explosives has a bearing on this problem, yet the shapes and size distributions of the explosive
particles remaining after detonations are not known. We collected residues from 8 high-order and 6
low-order non-tactical detonations of TNT-filled 155-mm rounds. We found significant variation in the
amount of TNT scattered from the high-order detonations, ranging from 0.00001 to 2% of the TNT in the
original shell. All low-order detonations scattered percent-level amounts of TNT. We imaged thousands of
TNT particles and determined the size, mass and surface-area distributions of particles collected from one
high-order and one low-order detonation. For the high-order detonation, particles smaller than 1 mm
contribute most of the mass and surface area of the TNT scattered. For the low-order detonation, most of
the scattered TNT mass was in the form of un-heated, centimeter-sized pieces whereas most of the surface
area was again from particles smaller than 1 mm. We also observed that the large pieces of TNT
disintegrate readily, giving rise to many smaller particles that can quickly dissolve. We suggest picking up
the large pieces of TNT before they disintegrate to become point sources of contamination.
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF
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358 S.Tayloretal./Chemosphere55(2004)357–367
humanhealthrisks.Estimatingtheloadofexplosiveson determinetherelationshipbetweendetonationyieldand
DOD training ranges is a difficult task (Jenkins et al., the mass of remainingresidue.
2001; Pennington et al., 2002). It requires information We sampled detonation residues from 155-mm
on how much explosive residue is deposited after dif- howitzerroundsdetonatedatCampEthanAllenandat
ferentmunitionsarefiredintoanareaandthevariation BlossomPoint.Theseroundscontained6.76kgof2,4,6-
in this deposition due to how the munition detonates trinitrotoluene (TNT). Our goals were to (1) determine
(dud, low-order or high-order, Dauphin and Doyle, the mass of scattered TNT particles and the resulting
2000). Once on the ground, the rate of degradation of size distributions, and (2) estimate surface areas for
the deposited explosive particles probably depends on theseparticlesusingtheirmeasuredlengthsandwidths.
their size distribution and surface areas as well as These data are needed as input parameters for models
weather and soil conditions (Ro et al., 1996; Lynch thatdeterminethemasstransferofTNTfromthesolid
etal., 2001,2002). phase to solution in water, a rate-limiting step that oc-
In this paper we use the term detonation residue to curspriorto aqueoustransportorbiodegradation. The
describe material collected after an explosion. The resi- rounds were blown-in-place and not fired from a how-
due may or may not contain explosives. The TNT we itzerasdesigned(tacticallydetonated).Thissetupmade
collected during this study was in the form of particles it possible for us to place trays around the detonation
and large pieces that had been scattered. We refer to point but may produce different results than tactically
them as TNT particles or scattered TNT. The yield of detonated rounds. Our results may be germane to
the detonation is the proportion of the explosive mass tactically detonated rounds provided that the yield of
that detonates. In principle, it can be quantified based a detonation, not the initiation process, governs the
onair-blastparameters(KingeryandBulmash,1984).A amount and the size distribution of the scattered
detonation may be measurably less than 100% yield if explosives.
thedetonationwavedoesnotpropagateproperlyowing
to defects in the shell casingorif the explosive wasnot
packed or poured properly into the shell. The method 2. Methods
used to initiate the detonation may also affect its yield.
Theterm ‘‘order’’is asubjective classification ofexplo- 2.1. Particle sampling
siveyield.Anobserverwouldclassifyashigh-orderany
explosionindistinguishablefrom100%yieldandaslow- 2.1.1. CampEthanAllen(CEA), Vermont
orderanexplosionclearlysoundingorlookingdifferent On 28 February 2002 seven 155-mm howitzer shells
than100%yield. were detonated to collect data on high-order detona-
Detonations conducted in a blast chamber are used tions for the SERDP CP1155 project. The 155-mm
to assess gases produced during a detonation. If the shellswerehungabout1moffthesnowsurfacefroma
chambercouldbeadequatelycleanedbetweenblastsand wooden frame. A 0.57-kg (1.25-lb) block of C4 was
iftheexplosionitselfwerenotmodifiedbytheconfined tapedtothesideoftheshellsandinitiatedelectronically.
spaceandlimitedair,ablastchamberwouldbeagood We mapped the resulting residue plumes using a geo-
place to measure the amount of explosives remaining positioningsystem(GPS)andsampled100-·100-·2.5-
after a detonation. Because of these issues, however, cm sections of the snow surface to obtain an average
fielddetonationsareuseddespitethedifficultiesinvolved explosive concentration.
in fieldsampling. Webaggedthesnowsamples,broughtthembackto
To estimate the mass of explosives remaining after thelaboratory,andsetthemoutatroomtemperatureto
high-order detonations, Jenkins et al. (2000a) collected melt.WefilteredeachwatersamplethroughaWhatman
and analyzed residue-covered snow samples from win- glass micro-fiber filter (47 mm, grade GF/A) and ex-
tertime detonations at Camp Ethan Allen, Vermont. tracted the water and the filter separately. The samples
The frozen ground minimized soil contamination, and were then analyzed for explosiveswith a Reverse phase
the snow provided a clean sampling background that High Performance Liquid Chromatograph (RP-HPLC)
decreasedthechancesofcross-contaminationfromprior following method 8330 (EPA, 1994). The latter is the
range activities. The snow also made the dark detona- standard method for determining explosive concentra-
tionresiduehighlyvisible,allowingtheresidueplumeto tion in waterand insoil.
bemappedandmeasured. To collect scattered TNT particles, we set out four,
To estimate the mass of explosives remaining after 66-·46-cm aluminum trays aroundtwo of the 155-mm
low-orderdetonations,Penningtonetal.(2003)sampled rounds(Tests1and5).Byusingthetrays,weminimized
theresiduesfromdetonationsonalargetarpatBlossom theamountofsnowcollectedwiththeresidue.TheGPS
Point, Maryland. The tarp also helped minimize cross- was also used to measure the distance between the
contamination from previous tests. The air-blast char- sample points and the crater. Fig. 1 shows the location
acteristics from each detonation were also measured to ofthesnowsamplesandthetrays(markedbytriangles)
S.Tayloretal./Chemosphere55(2004)357–367 359
Fig. 1. The positions of the snow samples and the trays
(marked by triangles) at Camp Ethan Allen relative to the
detonation point.A 5-m/swestblowingwindwasresponsible
fortheshapeoftheplume(sootdarkenedareasofsnow).The
sootiestareaoftheplumeisdelineatedbytheinnerlineandthe
visibleplumebytheouterline.
Fig. 2. Drawing that shows the position of trays at Blossom
relative to the detonation point for Test 1. We also Pointrelativetothedetonationpoint.Ourdatacomesfromthe
examinedtheresidueonthefilterusedforsnowsample N,W,SandEtrays.
S1(1 m2)from Test 1.
Aftereachdetonation,thetrayswereplacedinclear
AtBlossomPointthesoliddebrisoneachplatewas
plastic bags and brought back to the laboratory. Any
brushed into a 120-ml, wide-mouth, amber glass jar
snow on the trays was allowed to melt and evaporate.
usingacottonball.Asmallamountofacetonewasthen
Wemovedtheresiduefromeachtraydowntoacorner
pouredontothecottonballanditwasusedtowipethe
of the tray using a small paintbrush. The residue was
tray. One to three acetone-wetted swipes were used for
then transferred onto weigh paper, weighed, and then
each tray to remove the residues before we reuse the
storedina40-mlambervial.Eachtraywasthenwiped
traysforsampling.Thecottonballsfromeachtraywere
downwithacottonballsoakedwithapproximately3-ml
placedinto separate20-ml amberglassvials.
of acetone. The cotton balls, up to three for each tray,
were placedin a separateambervial.
2.2.Particle identificationandanalysis
2.1.2.Blossom Point (BP), Maryland For the size distributions we processed particles ob-
In May 2002, we sampled from low-order detona- tainedfromonehigh-orderandonelow-ordertest,Test
tionsconductedattheBlossomPointtestsite,anArmy 1atCampEthanAllenandTestLO7atBlossomPoint,
Research Laboratory facility (Pennington et al., 2003). respectively. We dry-sieved the samples into <53-, 53–
All seven 155-mm rounds were detonated using a main 106-, 106–125-, 125–180-, 180–250-, 250–500-, and
charge disruptor, a tool that pierces the shell of the >500-lm size-fractions. The sieved samples were re-
round using a small shape charge containing 50–230 g weighedandplacedintolabeledvials.Betweensamples,
of C4. Based on shock-wave measurements one of the thesieveswerecleanedusingabrushandpressurizedair
detonations was essentially 100% yield and the others toremove materialcaught inthe mesh.
ranged between 23% and 47% yield (Pennington et al., Sub-samples of each size fraction were examined
2003). The munitions were detonated on a 184-(cid:1) under a light microscope. To establish that certain
230-·6-cm thick steel slab on top of an 86-cm-high classes of particles were TNT we used tetra-butyl-
wooden base centered on a 15- by 15-m (50- by 50-ft) ammonium hydroxide, a reagent that reacts with TNT
white, flame resistant tarp. For each detonation, alu- toformaredproduct.Usingalightmicroscope,wethen
minum trays (66-·46-cm) were placed in a set pattern separatedoutalltheexplosivegrainsfromthe250–500-
around the detonation point (Fig. 2). The furthest tray to >500-lm size-fractions. For Camp Ethan Allen-Test
was 9 m from the detonation point and extended past 1, we measured 122 TNT particles from the east tray
the flame resistant tarp. After each detonation, we sample and 1296 TNT particles from the filtered snow
visually inspected both the tarp and the surrounding sample S1. For Blossom Point-LO7, we measured 3225
area to locate any centimeter-size pieces of explosive TNT particles collected from 12 sample trays placed
ejected from the round. These pieces were weighed and alongthemaincompassheadings(N,S,E,W)and207-
photographed in the field. cm-sized pieces hand collected from the tarp and the
360 S.Tayloretal./Chemosphere55(2004)357–367
nearby vicinity. The particles were measured in the fol-
lowing manner. We first photographed all the TNT
particles using a digital camera attached to the light
microscope(oradigitalcameraonly,forthecentimeter-
sized particles) and transferred the images to a Macin-
tosh computer. Then we used NIH image, a public
domain program developed at the US National Insti-
tutes of Health and available on the Internet at http://
rsb.info.nih.gov/nih-image/) to process each image and
obtain the number of TNT particles, as well as the
lengthof themajor and minoraxesfor eachparticle.
Weusedtheaxesmeasurementstocalculateaverage
diameter(averageofmajorandminoraxeslengths)and
aspectratio(major/minorlengthratio)foreachparticle.
We estimated particle mass and surface area using two
simple shape approximations: sphere (based on aver-
age diameter) and prolate spheroid (major>minor¼
unmeasuredthirdaxis).Wealso imagedthesurfacesof
some of the >250 lm TNT grains using a scanning
electronmicroscope(SEM)togetavisualrecordoftheir
surface roughness. Fig. 3.OpticalimageshowingTNTparticles(arrows)inresi-
due from a (cid:1)high-order’ detonation. The TNT particles are
To estimate the number of TNT particles in the five
opaque white to gray and often have black soot patches on
sizefractionssmallerthan250lm,wedissolvedallora
partsoftheirsurfaces.
large sub-sample of the residue in acetonitrile, agitated
the sample overnight and analyzed a fraction of the
indented surface. Unlike the quartz grains, the TNT
sample with a RP-HPLC following EPA method 8330
particles could be indented with a needle. The SEM
(EPA, 1994). From the measured TNT concentration,
images show that the surfaces are quite smooth, lumpy
wecalculatedtheTNTmassineachsizefraction.When
and non-porous. The underlying crystalline nature of
only a sub-sample was analyzed, we assumed it was
the TNT canalso bediscerned (Fig. 4).
representative of the entire size fraction. We then cal-
AwidervarietyofTNTparticleswerefoundafterthe
culated the number of particles and the total surface
Blossom Point-LO7 detonation (Fig. 5a–d). The larger
areaineachsizefraction,usingbothsphereandprolate-
onestendedtobeyellowtopinkcrystallineparticlesthat
spheroid approximations, by assuming an average
were very friable; they disaggregated into very small
diameter for each size fraction and using the average
particleswhentouchedbyaneedleortweezers.Wealso
aspect ratio of the sized particles from that same test.
observed white opaque particles, such as those previ-
Theaveragediameterschosenwere40,75,110,150and
ously described for the Camp Ethan Allen-Test 1 sam-
200 lm, respectively, for the <53-, 53–106-, 106–125-,
ples, yellow, lumpy particles, and spherical particles
125–180- and 180–250-lm size-fractions. The measured
(Fig.5d).ItisclearthatsomeoftheTNTparticleswere
aspect ratios were uncorrelated with particle size and
still molten or hot when they landed on the aluminum
averaged1.44±0.31(1r)and1.42±0.38(1r)forCamp
trays. We saw TNT (cid:1)splat’ marks on the trays, and we
Ethan Allen-Test 1 and Blossom Point-LO7, respec-
sawparticlesthathadflatbottomsfromlandingonthe
tively. Lastly, we added the resulting numbers, masses
tray whiletheywere still hotanddeformable.
and surface areas calculated from TNT concentrations
The SEM and optical images and measured aspect
tothebinnedresultsbasedonmeasuredparticlesizesto
ratiossuggestthat,forboththehighandlow-ordertest,
producehistograms.
the TNT particle are better approximated as prolate
spheroids rather than spheres. Because sphere and pro-
late-spheroid shape approximations give essentially the
3.Results
same size distributions and less than 4% difference in
mass and surface-area estimates, all of the analyses we
3.1.Appearanceof TNTparticles
show assumea prolate-spheroid shape.
TheCampEthanAllen-Test1TNTparticleswereall
opaque white to gray and often had a black carbon 3.2. Sizedistribution ofTNT particles
coating on part of their surfaces (Fig. 3). They differed
fromquartzgrains,whichwerealsofoundinthesample, The size distributions of the TNT particles from
by having a dull luster and an irregular, smooth and CampEthanAllen-Test1andfromBlossomPoint-LO7
S.Tayloretal./Chemosphere55(2004)357–367 361
Fig. 4.ScanningelectronmicrographsofTNTparticlesfromCampEthanAllen.Patchesofdifferenttexturearesootlikethoseseen
inFig.3.
Fig. 5. Optical images of TNT pieces and particles collected after a low-order detonation (Blossom Point-LO7), (a) >1 kg piece,
(b)assortmentof10–100gpieces(15-cmrulerforscale),(c)materialcollectedfromSEquadrant(bootforscale),(d)TNTparticles
fromtrays.
362 S.Tayloretal./Chemosphere55(2004)357–367
cles,butthesmallnumberandmassofparticlesmissed
107 shouldhaveaminoreffectontheresultspresentedhere.
For Blossom Point-LO7, we produced a histogram
m-1) 105 CEA-Test1 for the combined 12-tray sample and scaled this to the
m 18-m·18-m pattern covered by the trays (324 m2/3.62
dth ( 103 m2). We then added in the 207-cm-sized hand-collected
Wi piecestothescaledhistogram.Essentiallythisprocedure
n-
es/Bi 101 BP-LO7 athsseupmoepsutlahtaitonthoef1s2cattrtaeyredsaTmNplTespaadretiqculeasteslmyarleleprretsheannt
cl
arti 10-1 about1cm,andthatthehand-collectedpiecesconstitute
P the entire population of >1 cm TNT particles. We esti-
mate that this procedure adequately represents the size
10-3
10-2 10-1 100 101 102 103 distribution for Blossom Point-LO7 within the uncer-
tainty ofthe experiment.
Average Diameter (mm)
Fig. 6. Size distribution of TNT grains from the east tray 3.3. Cumulative distributions formass andsurfacearea
sample and S1 snow sample, Camp Ethan Allen, VT (open
circles)andfrom12trayssamples,BlossomPoint,MD(open
We plotted the cumulative distributions for TNT
squares).Theslopesofthebest-fitlinesare)2.4fortheCamp
particle mass and surface area versus average diameter
EthanAllen-Test1and)3.3forBlossomPoint-LO7,withR2of
for Camp Ethan Allen-Test 1 and Blossom Point-LO7
0.99and0.83,respectively.
(Fig.7).Aswiththesizedistributions,theresultsshown
are scaled to approximate the total mass and surface
areshowninFig.6andTable1.Thedataarepresented area of particles scattered by the two detonations. For
as thenumber of particles perbinwidth to accountfor ease of comparison, we normalized the curves by
the fact that the sieves, used to separate the samples, dividing by these calculated totals (0.133 kg and 0.566
yielded variable size fractions. The low-order test m2 for Camp Ethan Allen-Test 1, 2.95 kg and 1.94 m2
(Blossom Point-LO7) scattered much larger TNT par- for Blossom Point-LO7). Table 1 presents the cumula-
ticles than the high-order test (Camp Ethan Allen-Test tive masses andsurface areas beforenormalization.
1), including one exceeding 10 cm in size (Figs. 6 and ForCampEthanAllen-Test1,particlessmallerthan
5a). Interestingly, the size distributions nearly overlap 1 mm contribute most of the cumulative mass and sur-
forparticles smaller thana fewmillimeters. facearea.ForBlossomPoint-LO7,particleslargerthan
Except for the <53-lm size fraction for Blossom 1 cm contribute most of the cumulative mass while
Point-LO7,thesizedistributionsarewellrepresentedby particlessmallerthan1mmagaincontributemostofthe
power-laws(straightlinesonlog–logplots,Fig.6).The cumulative surface area. The larger surface area of the
slopesoftheselinesare)2.4fortheCampEthanAllen- small particles indicates that this size fraction will
Test1and)3.3forBlossomPoint-LO7,withR2 of0.99 interact with available water and dissolve. With time,
and 0.83, respectively. As explained in the Discussion, these smaller particles will disappear and only larger
the slope of the size distribution will change as the particles of TNTwill remainin the soil.
particlesweatherandthewayinwhichtheslopechanges
provides information on the dominant process altering 3.4. Total TNTmassdeposited
the scattered particles.
Note that we have scaled the sample results to esti- 3.4.1. CampEthanAllenhigh-order tests
matethetotalnumberofparticlesexpectedtohavebeen We measured the TNT concentrations for the 15
scattered by each detonation. For Camp Ethan Allen- snowsamplescollectedafterTest1(Table2).Exceptfor
Test1,weassumethattheplumeapproximatestheareal sample S1, where we measured the TNT particles, the
extentofthescatteredTNTparticles.Theeasttrayand other14snow samples wereextracted andanalyzed for
snow-sample S1 were the only samples located within TNT. The average TNT concentration thus obtained
the 496-m2 plume. We therefore combined and scaled was 0.220 g/m2 of snow, which, whenmultiplied bythe
their histograms by the area ratio 496 m2/1.30 m2 to 496m2 areaofthe visibleplume,yields aTNTmassof
estimate the particle content of the entire plume. These 109 g. Adding 1.80 g calculated for the crater produces
two samples had a combined TNT mass of 321 mg. an estimate of 111 g of TNT scattered from this deto-
While the south and west trays had insignificant TNT nation.Thisis1.64%ofthe6.76kgofTNTcontainedin
quantities(<0.1and3.5lg,respectively),thenorthtray a 155-mm shell. However, the uncertainty in the calcu-
hadthreelargeparticlesofTNT(averagediametersof4, lated TNT quantity could be ±50%, owing to the large
3,and1mm) andaTNT massofabout8 mg.Clearly, range among the 15 measured TNT concentrations.
the plume did not contain all the scattered TNT parti- That is, the concentration measurements suggest that
S.Tayloretal./Chemosphere55(2004)357–367 363
Table 1
Binnedresultsforparticlenumbers,massandsurfaceareaforCampEthanAllen-Test1andBlossomPoint-LO7
Binrange(lm) Bindiameter(lm) Numberofparticles Mass(g) Surfacearea(mm2)
CampEthanAllen-Test1
<0.053 0.040 3.95E+06 0.173 1.74E+04
0.053–0.106 0.075 6.74E+05 0.195 1.04E+04
0.106–0.125 0.110 1.33E+05 0.122 4.44E+03
0.125–0.180 0.150 1.52E+05 0.355 9.47E+03
0.180–0.250 0.200 2.86E+05 1.60 3.18E+04
0.250–0.500 0.375 2.91E+05 14.3 1.35E+05
0.500–1.0 0.750 2.11E+05 41.9 2.44E+05
1.0–1.5 1.25 1.30E+04 14.7 4.91E+04
1.5–2.0 1.75 2.67E+03 8.33 2.01E+04
2.0–2.5 2.25 1.52E+03 9.61 1.85E+04
2.5–3.0 2.75 0 0 0
3.0–3.5 3.25 0 0 0
3.5–4.0 3.75 0 0 0
4.0–4.5 4.25 0 0 0
4.5–5.0 4.75 3.81E+02 30.8 2.47E+04
BlossomPoint-LO7
<0.053 0.040 1.35E+06 0.0599 5.98E+03
0.053–0.106 0.075 4.52E+06 1.32 7.03E+04
0.106–0.125 0.110 6.70E+05 0.618 2.24E+04
0.125–0.180 0.150 2.59E+06 6.06 1.61E+05
0.180–0.250 0.200 1.16E+06 6.45 1.29E+05
0.250–0.300 0.275 3.18E+05 4.58 6.66E+04
0.300–0.425 0.350 8.21E+05 24.4 2.78E+05
0.425–1.0 0.750 1.72E+05 71.8 3.33E+05
1.0–2.0 1.5 1.08E+05 166 4.93E+05
2.0–3.0 2.5 5.99E+03 52.9 8.96E+04
3.0–4.0 3.5 1.17E+03 29.1 3.54E+04
4.0–5.0 4.5 2.96E+02 19.4 1.68E+04
5.0–6.0 5.5 27 3.97 2.65E+03
6.0–7.0 6.5 196 30.0 2.01E+04
7.0–8.0 7.5 18 6.61 3.26E+03
8.0–9.0 8.5 100 48.8 2.18E+04
9.0–10 9.5 8 5.77 2.27E+03
10–20 15 55 146 3.60E+04
20–30 25 22 244 3.81E+04
30–40 35 7 293 2.98E+04
40–50 45 4 369 2.87E+04
50–60 55 1 108 8.02E+03
60–70 65 1 221 1.29E+04
70–80 75 0 0 0
80–90 85 0 0 0
90–100 95 0 0 0
100–200 150 1 1087 3.74E+04
the detonation scattered about 2±1% of the explosive estimates is satisfying but possibly fortuitous given the
charge. largeuncertainties involved.
If instead we use the number of TNT particles we We also list the concentration measurements ob-
found in S1 and the east tray (Table 1) to estimate the tained for Test 4, another high-order detonation of a
TNT mass scattered by the detonation we obtain an 155-mmround(Table2).Forthistest,theaverageTNT
average TNT concentration of 0.268 g/m2 in the snow concentration from nine snow samples gave a total
whichwhenmultipliedby496m2yields133g.Thismass depositedTNTmassof0.5±0.3mg,roughly5ordersof
is 1.96% of the TNT charge in the shell, but we should magnitude lower than Test 1. The masses of TNT esti-
also allow ±50% uncertainty in this method and report mated for the other 155-mm tests conducted at Camp
the result as 2±1%. The agreement between these two Ethan Allen, based on concentration measurements of
364 S.Tayloretal./Chemosphere55(2004)357–367
from the entire surface of the tarp and consequently
1.00
were notscaled.
Measurements of the blast wave for this low-order
ulativeArea 0.75 tmesatssgainvethane erostuimndat(eRdeyeide,ld20o0f23,7b%asoefdthoenoKriignignearlyTaNnTd
mmce Bulmash,1984).Althoughanuncertaintywasnotgiven,
d CuSurfa 0.50 Surface Area Mass the high-order detonations varied by almost 20% in
zeor estimated yields. The asymmetric nature of a low-order
alis detonation probably significantly increases the uncer-
mas
orM 0.25 tainty in its yield estimated from blast-wave measure-
N
ments. Consequently, we may estimate the yield of
CEA-test1 Blossom Point-LO7as 40±20%.
0.0010-2 10-1 100 101 102 103 These two measurements allow us to account for
80±20% of the original explosive mass in the round:
(a) Average Diameter (mm)
44±4% scattered mass and 40±20% yield mass, roun-
dedto reflectthe highuncertaintyin theyieldestimate.
1.00
SomeTNTwasleftintheshellbutwewerenotallowed
to remove it, some TNT may have been burned in the
ulativeArea0.75 fitirmebetaelrl-sainzdedwsecamttaeryednoptahrtaicvleesr.ecovered all of the cen-
me
mc
d CuSurfa0.50 Surface Area Mass 4. Discussion
zeor
alis
ormMas0.25 Theresultspresentedhereare,toourknowledge,the
N first reported size, mass and surface-area distributions
BP-LO7 forexplosiveparticlesscatteredbydetonations.Oncewe
0.00 identifiedthetypesofTNTparticlescollected,theywere
10-2 10-1 100 101 102 103 relativelyeasytopickoutfromtheexplosiveresidueand
(b) Average Diameter (mm) soil collected on the trays. However, the time-intensive
nature of imaging the particles to produce size distri-
Fig. 7. Normalized cumulative mass and surface area, as a
butions limited the results presented here to just two
functionofparticlediameter,forTNTcollectedfrom(a)Test1
atCampEthanAllen,Vermontand(b)LO7atBlossomPoint, detonations. Note also that the detonations were trig-
Maryland.Themassesandsurfaceareaswerecalculatedbased gered by methods used for blow-in-place operations. It
onaprolateparticleshape.Tomakeiteasiertocomparethe isunclearatpresenthowcloselytheseresultswillapply
distributionshapeswenormalizedthecountsbythetotalmass to tactically detonated rounds.
and surface area calculated for each test. The total mass at The variety of sizes, colors and textures of the scat-
CampEthanAllenwas0.133kgandatBlossomPoint2.95kg. teredTNTparticlesaretheresultofdifferentialheating,
Thetotalsurfaceareawas0.566m2forCampEthanAllen-Test
with the crystalline particles being the least heated and
1and1.94m2 forBlossomPoint-LO7.
the spheres having been totally melted during the deto-
nation. TNT particles that have been heated or melted
the snow samples, fall betweenthe values for thesetwo
tendalsotohavesmoothsurfaceswhereastheunmelted
tests(Table3).
crystalline particles have rougher surfaces. Also, the
crystalline particles are friable and readily break apart
3.4.2.Blossom Point-LO7 into smaller pieces.
Our estimate for the mass of TNT scattered by test The measured size distributions for Camp Ethan
LO7 consists of two calculations. The mass of TNT Allen-Test1andBlossomPoint-LO7nearlyoverlapfor
particlescollectedonthe12trayswasscaledbythearea particlessmallerthanafewmillimeters.Thehigh-order
of the tarp to obtain an estimate for the small sized CampEthanAllen-Test1scatteredsmallTNTparticles
particlesof0.45±0.22kg.Tothisweaddedthemassof withcharacteristicssimilartothosescatteredbythelow-
the>1-cmpiecesthatwepickedupfromtheentiretarp orderBlossomPoint-LO7withayieldofonly40±20%.
anditsvicinity,2.5±0.2kg.Thesumoftheseis2.9±0.3 Thelow-ordertestdifferedprimarilybyscatteringafew
kg or 44±4% of the TNT in the round. Although we largeparticlesthatrepresentmostofthescatteredmass.
againallowed±50%uncertaintyinthemassscaledfrom We saw TNT particles in the smallest size fractions
the 12 trays, the total scattered mass for this test is frombothCampEthanAllen-Test1andBlossomPoint-
dominated by the picked up chunks that we collected LO7.Weexpectthatthesesmall,ubiquitousTNTgrains