Ecotoxicology of Explosives

ECOTOXICOLOGY OF EXPLOSIVES

© 2009 by Taylor and Francis Group, LLC

ECOTOXICOLOGY OF EXPLOSIVES Edited by

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CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2009 by Taylor and Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed in the United States of America on acid-free paper 10 9 8 7 6 5 4 3 2 1 International Standard Book Number: 978-0-8493-2839-8 (Hardback) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright. com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data Ecotoxicology of explosives / editors, Geoffrey I. Sunahara ... [et al.]. p. cm. Includes bibliographical references and index. ISBN 978-0-8493-2839-8 (hardcover : alk. paper) 1. Explosives--Toxicology. 2. Explosives--Environmental aspects. I. Sunahara, Geoffrey I. (Geoffrey Isao), 1953- II. Title. RA1270.E93E36 2009 363.17’98--dc22 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

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2009015403

Contents List of Figures ..........................................................................................................vii List of Tables.............................................................................................................ix Preface.................................................................................................................... xiii The Editors............................................................................................................... xv Contributors ............................................................................................................xix Abbreviations ....................................................................................................... xxiii Chapter 1

Introduction .......................................................................................... 1 Geoffrey I. Sunahara, Roman G. Kuperman, Guilherme R. Lotufo, Jalal Hawari, Sonia Thiboutot, and Guy Ampleman

Chapter 2

Fate and Transport of Explosives in the Environment: A Chemist’s View..................................................................................... 5 Fanny Monteil-Rivera, Annamaria Halasz, Carl Groom, Jian-Shen Zhao, Sonia Thiboutot, Guy Ampleman, and Jalal Hawari

Chapter 3

Effects of Energetic Materials on Soil Organisms............................. 35 Roman G. Kuperman, Michael Simini, Steven Siciliano, and Ping Gong

Chapter 4

Aquatic Toxicology of Explosives...................................................... 77 Marion Nipper, R. Scott Carr, and Guilherme R. Lotufo

Chapter 5

Fate and Toxicity of Explosives in Sediments.................................. 117 Guilherme R. Lotufo, Marion Nipper, R. Scott Carr, and Jason M. Conder

Chapter 6

Bioconcentration, Bioaccumulation, and Biotransformation of Explosives and Related Compounds in Aquatic Organisms ............ 135 Guilherme R. Lotufo, Michael J. Lydy, Gregory L. Rorrer, Octavio Cruz-Uribe, and Donald P. Cheney

Chapter 7

Toxicity of Energetic Compounds to Wildlife Species .................... 157 Mark S. Johnson and Christopher J. Salice

v © 2009 by Taylor and Francis Group, LLC

vi

Chapter 8

Contents

Genotoxicity of Explosives............................................................... 177 Laura Inouye, Bernard Lachance, and Ping Gong

Chapter 9

Mechanisms of the Mammalian Cell Cytotoxicity of Explosives ... 211 Narimantas Cˇe˙ nas, Aušra Nemeikaite˙ -Cˇe˙ niene˙ , Jonas Šarlauskas, Žilvinas Anusevicˇ ius, Henrikas Nivinskas, Lina Misevicˇiene˙ , and Audroné Maroziene˙

Chapter 10 Bioconcentration, Bioaccumulation, and Biomagnification of Nitroaromatic and Nitramine Explosives in Terrestrial Systems..... 227 Mark S. Johnson, Christopher J. Salice, Bradley E. Sample, and Pierre Yves Robidoux Chapter 11 Habitat Disturbance at Explosives-Contaminated Ranges............... 253 Rebecca A. Efroymson, Valerie Morrill, Virginia H. Dale, Thomas F. Jenkins, and Neil R. Giffen Chapter 12 Ecological Risk Assessment of Soil Contamination with Munition Constituents in North America......................................... 277 Roman G. Kuperman, Ronald T. Checkai, Mark S. Johnson, Pierre Yves Robidoux, Bernard Lachance, Sonia Thiboutot, and Guy Ampleman Chapter 13 Closing Remarks ..............................................................................309 Guilherme R. Lotufo, Geoffrey I. Sunahara, Jalal Hawari, and Roman G. Kuperman

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List of Figures FIGURE 2.1 Abiotic transformation routes of TNT: (A) under photolytic conditions [23]; (B) in the presence of Fe(0) [24] or Fe(II) [25]; (C) under alkaline conditions [26]. FIGURE 2.2 Abiotic degradation pathways of RDX: (A) initiated by denitration (hydrolysis, photolysis, electrolysis, Fe(II), zero valent metals), or (B) initiated by reduction to the corresponding nitroso derivatives (2e-transfer) (photolysis, electrolysis, zero valent metals). (Data from Refs. 42, 48–50.) FIGURE 2.3 Proposed denitration routes of CL-20 by photolysis [60], zero valent iron [61], and salicylate 1-monooxygenase from Pseudomonas sp. strain ATCC 29352 [62], and degradation products of A (or B) intermediates. FIGURE 2.4 Biotransformation of TNT under aerobic and anaerobic conditions. TAT is only produced under strict anaerobic conditions. FIGURE 2.5 Biodegradation of RDX initiated by denitration under aerobic (path A) and anaerobic (path B) conditions. FIGURE 2.6 Biodegradation of RDX initiated by reduction to the nitroso derivatives followed by B-hydroxylation (path A), denitration (path B), or reduction (path C). FIGURE 3.1 Schematic toxicological impacts of TNT on the soil microbial community. FIGURE 3.2 The toxicity of TNT to the nitrogen and carbon soil biogeochemical cycles. Values are concentrations of TNT shown to inhibit the specified process by 50%. (For nitrification, the entire nitrification process is indicated but the assay only measures the production of nitrite and not nitrate. Numbers in brackets are references.) FIGURE 6.1 Relationship between the log bioconcentration factors (BCFs) for explosive and related compounds reported in Table 6.1 and log Kow. The solid line represents the best-fit linear equation (log BCF = 0.53 log Kow – 0.23, r 2 = 0.37) for all values except those with log BCF 11. At pH 12 and room temperature, nitroaromatics degraded in soil with rates decreasing in the following order: TNT (t1/2 = 2.9 h) > 2-ADNT (t1/2 = 6.2 h) ≈ 4-ADNT (t1/2 = 6.5 h) > 2,4-DNT (t1/2 = 8.4 h) [32]. The disappearance of TNT under alkaline conditions occurred via a rapid initial step in which a highly colored transient species (Mmax = 450 nm), identified as a Meisenheimer complex (T-anionic), was reversibly formed (Figure 2.1)

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Common Name

Molecular Weight (g mol–1)

Melting Point (°C)

Water Solubility at 25°C (mg L–1)

Octanol/Water Partition Coefficient (log Kow)

Henry’s Law Constant at 25°C (atm m3 mol–1)

Vapor Pressure at 25°C (mm Hg)

TNT

227.13

80.1

130 [3]

1.6 [4]

4.57 × 10–7 [4] a

1.99 × 10–4 [4] a

2,4-DNT

182.15

71

270 [4]

1.98 [4]

1.86 × 10–7 [5]

1.47 × 10–4 [4]

–11

Tetryl

287.17

129.5

75 [3]

2.04 [3]

2.69 × 10

[5]

TATB

258.15

ND

32 [3]

0.7 [3]

5.8 × 10–12 [3] –8

5.69 × 10–9 [5] 1.34 × 10–11 [3]

Picric Acid

229.10

121.8

12800 [4]

1.33 [4]

1.7 × 10 [4]

7.5 × 10–7 [4]

NC

105–106 [6]

206 [7]b

Insoluble [5]

NDc

ND

ND –9

PETN

316.17

143.3

43 [4]

3.71 [5]

1.7 × 10 [5]

5.38 × 10–9 [5]

NG

227.11

13.5

1800 [4]

1.62 [4]

3.4 × 10–6 [3] a

2 × 10–4 [4]

–6

EGDN

152.08

–22.3

5200 [4]

1.16 [4]

2.52 × 10 [5]

7.2 × 10–2 [4]

RDX

222.26

205

56.3 [8]

0.90 [8]

1.96 × 10–11 [5]

4.0 × 10–9 [5]

HMX

296.16

286

4.5 [8]

0.17 [8]

2.60 × 10

CL-20

438.19

260b

3.7 [8]

1.92 [8]

ND

–15

[5]

Fate and Transport of Explosives in the Environment

TABLE 2.2 Most Commonly Used Physicochemical Properties of Some of the Explosives Needed for Environmental Risk Assessment

3.3 × 10–14 [5] ND

–16

NGu

104.07

239

4400 [4]

–0.89 [4]

4.67 × 10

GAP

1700–2300 [9]

ND

ND

ND

ND

[5]

1.43 × 10–11 [5] ND

Note: ND = Not determined. a At 20°C. b With decomposition.

9

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10

Ecotoxicology of Explosives CH3 O2N

NO2

NO2 TNT A

CH2 O2N

CH2OO NO2 H2N

NO2

NH2

NO2 2-ADNT major

NH2 4-ADNT minor

CH3

CH3 NH2

COOH

NO2 2,4,6-Trinitrobenzoic acid

NO2

O2N

O2N

NO2 2,6-DANT

NO2

HO CH3

CH3

O 2N

NO2

O2N

C

CH3 NO2

O2N

B

NO2

O2N

NO2 Meisenheimer complex

NH2

NH2 2,4-DANT

?

CH3 H2N

NH2

NH2 TAT

FIGURE 2.1 Abiotic transformation routes of TNT: (A) under photolytic conditions [23]; (B) in the presence of Fe(0) [24] or Fe(II) [25]; (C) under alkaline conditions [26].

[26,33]. This colored complex was used to develop colorimetric tests for many nitro aromatic compounds. Whether the Meisenheimer complex or 2,4,6-trinitrobenzyl anion (TNT–) resulting from proton abstraction reacted further with TNT (or with excess hydroxide) to form larger species is still not clear, but alkaline hydrolysis of TNT in aqueous media led to large molecular weight compounds (60% > 30 kDa [28]; 40% > 1 kDa [30]).

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Fate and Transport of Explosives in the Environment

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2.2.1.1.2 Photolysis In addition to hydrolysis, photolysis is recognized as another environmentally important mechanism for the removal (attenuation) of organic pollutants in natural surface waters [34]. Several approaches including solar photolysis [35–39], UV (ultraviolet) photolysis [35], UV peroxide [40], UV ozone, and TiO2 photocatalysis [23,41] have been employed to treat TNT-contaminated water. The rate of photolysis was pH-dependent, increasing threefold as pH increased from 4 to 8 [36]. In most cases, TNT photolysis yields a variety of products including 4-ADNT, 3,5-dinitroaniline, 2,4,6-trinitrophenol, 2,4,6-trinitrobenzyl alcohol, 2,4,6-trinitrobenzoic acid, and 1,3,5-trinitrobenzene (TNB), among which 2,4,6-trinitrobenzoic acid was the most often encountered [23]. Although the aromatic ring normally remains intact, ring cleavage and high mineralization rates could be achieved in the presence of a photocatalyst, such as TiO2 [23]. 2.2.1.1.3 Reduction by Iron The presence of metals in soil can also influence the fate and environmental impact of NACs. Zero valent iron, Fe(0), reduces TNT [24,42,43], 1,3,5-TNB [44,45], and 2,4-DNT [46] to partially or completely reduced amines. Furthermore, Fe(II) at the surface of Fe(III) (hydr)oxides reduces TNT and other NACs to corresponding aromatic polyamines [25,47]. In the case of Fe(0), using high-purity iron allowed complete reduction of TNT to 2,4,6-triaminotoluene (TAT), while scrap iron gave only partial reduction [24]. Both Fe(0) and Fe(II) led to the predominant formation of 2-ADNT over 4-ADNT. 2.2.1.2 Cyclic Nitramines The degradation of RDX under a variety of abiotic conditions (hydrolytic, photolytic, and reductive) is summarized in Figure 2.2 [42, 48–50]. 2.2.1.2.1 Alkaline Hydrolysis Cyclic nitramine explosives such as RDX and HMX degrade under alkaline conditions [49,51–54]. At pH 12 and 50°C, HMX hydrolysis (t1/2 = 2.5 h) occurred at a rate approximately 14 times slower than that of RDX (t1/2 = 10.9 min) [53]. The disappearance of RDX and HMX was concurrent with the formation of nitrite and corresponding imino intermediates (Figure 2.2, path A) [49,51], and both nitramines gave closely related product distributions (NO2–, N2O, NH3, N2, HCHO, and HCOO –). Using LC/ MS (liquid chromatography–mass spectrometry), Balakrishnan et al. [49] were able to directly detect the ring cleavage product 4-nitro-2,4-diazabutanal (NDAB), and thus provide experimental evidence of hydrolytic ring cleavage and decomposition (Figure 2.2, path A). CL-20 is also a heterocyclic nitramine, which like RDX and HMX, contains the characteristic N-NO2 functional groups (Table 2.1). However, in contrast to RDX and HMX, which are two-dimensional monocyclic nitramines, CL-20 is a polycyclic nitramine characterized by a strained three-dimensional cage structure. This structural difference may cause significant variations in the degradation pathways of CL-20 from those reported for RDX and HMX [55]. When challenged with alkaline conditions (pH 10), CL-20 degraded 1.5 times faster than RDX,

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Ecotoxicology of Explosives

NO–2

N N

A

N NO2

O2N

NO2

NO

N

N

N

B

N

O2N

NO2

N

N

O2N

NO2 MNX

RDX

Imine H2O H N N

OH N NO

NO2

O2N

α-hydroxynitramine

N N

H N N O2N

HN NO2

NH NO2

N

O2N

NO

CHO H N

DNX

NO2

HN NO2

MEDINA

NH

NO

CHO

N

NDAB N

N

ON N2O + NH2CHO + NH3 + HCHO + HCOOH

NO TNX

FIGURE 2.2 Abiotic degradation pathways of RDX: (A) initiated by denitration (hydrolysis, photolysis, electrolysis, Fe(II), zero valent metals), or (B) initiated by reduction to the corresponding nitroso derivatives (2e-transfer) (photolysis, electrolysis, zero valent metals). (Data from Refs. 42, 48–50.)

and led to the formation of NO2–, N2O, NH3, and HCOO –, with no formaldehyde detected [49]. 2.2.1.2.2 Photolysis Photolysis is another abiotic process that could contribute to the attenuation of nitramines in natural media. Because HMX is more resistant to degradation than RDX [49,52,53], very few reports pertain to HMX photolysis. However, several reports regarding the photodegradation of RDX [48,56–58] suggested that photolysis was accomplished through the initial homolysis of the N-NO2 bond. Such © 2009 by Taylor and Francis Group, LLC

Fate and Transport of Explosives in the Environment

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a bond scission ultimately yields products resembling those found in hydrolysis (HCHO, HCOOH, NH3, NO2 –, and N2O). In addition, Hawari et al. [48] identified two key intermediates, NDAB and methylenedinitramine (MEDINA, CH2(NHNO2)2), during the photolysis of RDX. The latter degrades spontaneously in water to form HCHO and N2O [59]. Recently, the rigid molecule CL-20 was also photolyzed and produced NO2 –, NO3 –, NH3, HCOOH, N2, and N2O, thereby suggesting a complete degradation of the chemical in water [60]. Several initial intermediates (A and B in Figure 2.3) involved in the degradation of CL-20 were detected, and tentatively identified using uniformly amino labeled 15N-[CL-20] and LC/MS (ES–) (liquid chromatography–electrospray (negative) ionization mass spectrometry) [60–62]. 2.2.1.2.3 Reduction by Iron Like TNT, nitramines can be abiotically degraded in the presence of reduced iron. Fe(0) was reported to degrade RDX to produce NH4+ and unidentified water-soluble compounds [24,42,63]. The nitroso byproducts—hexahydro-3,5-dinitro-1-nitroso1,3,5-triazine (MNX), hexahydro-5-nitro-1,3-dinitroso-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX; Figure 2.2, path B)—were usually detected within the first hours of reaction but never accumulated [63,64]. As the amount of TNX always remained small [63,64], it was suggested that nitro moiety reduction was not the sole pathway of RDX removal and that a second pathway involving initial denitration to give nitrite was occurring (Figure 2.2, path A). Using Fe(II) bound to magnetite to degrade RDX, Gregory et al. [50] recently observed similar reaction patterns and identified NH4+, N2O, and HCHO as stable products with the transient formation of MNX, DNX, and TNX. In the presence of Fe(0), CL-20 underwent rapid denitration (losing two equivalents NO2–) to ultimately produce N2O, ammonium, formate, glyoxal (H(O)C-C(O)H), and glycolic acid (CH2OHCOOH) [61]. LC/MS (ES–) measurements of Fe(0)-treated 15N-[CL-20] allowed identification of the denitrated imine intermediates detected earlier during the photolysis of CL-20 (Compounds A and B in Figure 2.3).

2.3 2.3.1

BIOTIC TRANSFORMATIONS NITROAROMATIC COMPOUNDS

Biodegradation of nitroaromatics has been reviewed by several groups [15,21,65–68]. The presence of nitro (–NO2) electron withdrawing groups on the aromatic ring protects nitroaromatics from initial attack by oxygenases and favors reduction. The lower number of –NO2 groups in DNTs compared to TNT greatly affects the reactivity of these compounds under aerobic and anaerobic conditions. 2.3.1.1 TNT Biotransformation Although TNT can be transformed under both aerobic and anaerobic conditions by bacteria and fungi (Table 2.3 [69–82] and Table 2.4 [83–88]), the presence of three nitro groups limits oxidative attack from aerobic organisms [89], and the reductive mechanism predominates. Reductive attack produces corresponding amino (–NH 2) © 2009 by Taylor and Francis Group, LLC

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Ecotoxicology of Explosives

N

O2N

N N

N

O2N N

O 2N

N 

O 2N O2N O 2N

N NO2

N

N

N

N

O2N

NO2

NO2

N N

O 2N

NO2 NO2



NO2

N NO2

N

N

O2N N

N

NO2



NO2

A NO2 N

B

NO2 N

NO2 N

NO2

NO2

N

N

N

N

N

N

+ N

A (or B)

N

N

NO2

NO2

H 2O

NO2

NO–2 + N2O + HCOOH + CHOCHO + NH3

FIGURE 2.3 Proposed denitration routes of CL-20 by photolysis [60], zero valent iron [61], and salicylate 1-monooxygenase from Pseudomonas sp. strain ATCC 29352 [62], and degradation products of A (or B) intermediates.

electron donating groups [90,91]. TNT first reduces to produce ADNTs (preferentially 4-ADNT) [92,93], and DANTs (preferentially 2,4-DANT). Only under strict anaerobic conditions does the reduction continue to produce TAT [94,95] (Figure 2.4). The resulting amines are not further degraded by anaerobes, and hence persist in

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Transformation Productsa Bacterial Strains Bacillus sp. Enterobacter cloacae PB2 Methylobacterium sp. Mycobacterium sp. HL 4NT-1 Mycobacterium vaccae JOB-5b Pseudomonas sp. clone Ab,c Pseudomonas aeruginosa MA01b,c Pseudomonas aeruginosa Pseudomonas aeruginosa MXc Pseudomonas pseudoalcaligens JS52 Pseudomonas savastanoi Pseudomonas fluorescens I-Cc,d Rhodococcus erythropolis HL PM-1 Serratia marcescens Streptomyces chromofuscus A11b Staphylococcus sp.

TNT (mg/L)

Degradation (%)

100 113 25 113 90 50 100 100 102 50 70 ND

95 98 100 98 100 100 98 100 99 100 100 ND

50 25 100

100 100 98

NO2–

Denitrated Products

Meisenheimer

ADNT

Reference

+ + ND + ND + ND + ND + + + – ND – +

2A4NT – ND – ND DNTs, 2-NT, T ND 2A4NT ND – 24DNT – – ND ND 2A4NT

ND + ND + ND + ND ND ND ND ND + + ND ND ND

+ ND + + + + + + + + + + + + + +

69 70 71 72 73 74 75 69 76 77 78 79 80 81 82 69

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Note: +, produced; –, not produced; ND, no data; T, toluene; NT, nitrotoluene; DNT, dinitrotoluene; 2A4NT, 2-amino-4-nitrotoluene; ADNT, aminodinitrotoluene. a Mineralization either not reported or