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Murillo-Gelvez J, Hickey K, Di Toro DM, Allen HE, Carbonaro RF, Chiu PC. Electron Transfer Energy and Hydrogen Atom Transfer Energy-Based Linear Free Energy Relationships for Predicting the Rate Constants of Munition Constituent Reduction by Hydroquinones. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5284-5295. [PMID: 36961098 DOI: 10.1021/acs.est.2c08931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
No single linear free energy relationship (LFER) exists that can predict reduction rate constants of all munition constituents (MCs). To address this knowledge gap, we measured the reduction rates of MCs and their surrogates including nitroaromatics [NACs; 2,4,6-trinitrotoluene (TNT), 2,4-dinitroanisole (DNAN), 2-amino-4,6-dinitrotoluene (2-A-DNT), 4-amino-2,6-dinitrotoluene (4-A-DNT), and 2,4-dinitrotoluene (DNT)], nitramines [hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and nitroguanidine (NQ)], and azoles [3-nitro-1,2,4-triazol-5-one (NTO) and 3,4-dinitropyrazole (DNP)] by three dithionite-reduced quinones (lawsone, AQDS, and AQS). All MCs/NACs were reduced by the hydroquinones except NQ. Hydroquinone and MC speciations were varied by controlling pH, permitting the application of a speciation model to determine second-order rate constants (k) from observed pseudo-first-order rate constants. The intrinsic reactivity of MCs (oxidants) decreased upon deprotonation, while the opposite was true for hydroquinones (reductants). The rate constants spanned ∼6 orders of magnitude in the order NTO ≈ TNT > DNP > DNT ≈ DNAN ≈ 2-A-DNT > DNP- > 4-A-DNT > NTO- > RDX. LFERs developed using density functional theory-calculated electron transfer and hydrogen atom transfer energies and reported one-electron reduction potentials successfully predicted k, suggesting that these structurally diverse MCs/NACs are all reduced by hydroquinones through the same mechanism and rate-limiting step. These results increase the applicability of LFER models for predicting the fate and half-lives of MCs and related nitro compounds in reducing environments.
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Affiliation(s)
- Jimmy Murillo-Gelvez
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Kevin Hickey
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Dominic M Di Toro
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Herbert E Allen
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Richard F Carbonaro
- Department of Chemical Engineering, Manhattan College, Riverdale, New York 10471, United States
- Mutch Associates LLC, Ramsey, New Jersey 07446, United States
| | - Pei C Chiu
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, United States
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2
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Schroer HW, Londono E, Li X, Lehmler HJ, Arnold W, Just CL. Photolysis of 3-Nitro-1,2,4-triazol-5-one: Mechanisms and Products. ACS ES&T WATER 2023; 3:783-792. [PMID: 36936519 PMCID: PMC10012174 DOI: 10.1021/acsestwater.2c00567] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Insensitive munitions formulations that include 3-nitro-1,2,4-triazol-5-one (NTO) are replacing traditional explosive compounds. While these new formulations have superior safety characteristics, the compounds have greater environmental mobility, raising concern over potential contamination and cleanup of training and manufacturing facilities. Here, we examine the mechanisms and products of NTO photolysis in simulated sunlight to further inform NTO degradation in sunlit surface waters. We demonstrate that NTO produces singlet oxygen and that dissolved oxygen increases the NTO photolysis rate in deionized water. The rate of NTO photolysis is independent of concentration and decreases slightly in the presence of Suwannee River Natural Organic Matter. The apparent quantum yield of NTO generally decreases as pH increases, ranging from 2.0 × 10-5 at pH 12 to 1.3 × 10-3 at pH 2. Bimolecular reaction rate constants for NTO with singlet oxygen and hydroxyl radical were measured to be (1.95 ± 0.15) × 106 and (3.28 ± 0.23) × 1010 M-1 s-1, respectively. Major photolysis reaction products were ammonium, nitrite, and nitrate, with nitrite produced in nearly stoichiometric yield upon the reaction of NTO with singlet oxygen. Environmental half-lives are predicted to span from 1.1 to 5.7 days. Taken together, these data enhance our understanding of NTO photolysis under environmentally relevant conditions.
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Affiliation(s)
- Hunter W. Schroer
- Civil
& Environmental Engineering, The University
of Iowa, Iowa City, Iowa52242, United States
| | - Esteban Londono
- Civil
& Environmental Engineering, The University
of Iowa, Iowa City, Iowa52242, United States
| | - Xueshu Li
- Occupational
& Environmental Health, The University
of Iowa, Iowa City, Iowa52246, United States
| | - Hans-Joachim Lehmler
- Occupational
& Environmental Health, The University
of Iowa, Iowa City, Iowa52246, United States
| | - William Arnold
- Department
of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Dr. SE, Minneapolis, Minnesota55455, United States
| | - Craig L. Just
- Civil
& Environmental Engineering, The University
of Iowa, Iowa City, Iowa52242, United States
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3
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Menezes O, Owens C, Rios-Valenciana EE, Sierra-Alvarez R, Field JA, Spain JC. Designing bacterial consortia for the complete biodegradation of insensitive munitions compounds in waste streams. Biotechnol Bioeng 2022; 119:2437-2446. [PMID: 35706349 DOI: 10.1002/bit.28160] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/24/2022] [Accepted: 06/13/2022] [Indexed: 11/08/2022]
Abstract
Insensitive munitions compounds (IMCs), such as 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO), are replacing conventional explosives in munitions formulations. Manufacture and use of IMCs generate waste streams in manufacturing plants and load/assemble/pack facilities. There is a lack of practical experience in executing biodegradation strategies to treat IMCs waste streams. This study establishes a proof-of-concept that bacterial consortia can be designed to mineralize IMCs and co-occurring nitroaromatics in waste streams. First, DNAN, 4-nitroanisole (4-NA), and 4-chloronitrobenzene (4-CNB) in a synthetic DNAN-manufacturing waste stream were biodegraded using an aerobic fluidized-bed reactor (FBR) inoculated with Nocardioides sp. JS 1661 (DNAN degrader), Rhodococcus sp. JS 3073 (4-NA degrader), and Comamonadaceae sp. LW1 (4-CNB degrader). No biodegradation was detected when the FBR was operated under anoxic conditions. Second, DNAN and NTO were biodegraded in a synthetic load/assemble/pack waste stream during a sequential treatment comprising: (i) aerobic DNAN biodegradation in the FBR; (ii) anaerobic NTO biotransformation to 3-amino-1,2,4-triazol-5-one (ATO) by an NTO-respiring enrichment; and (iii) aerobic ATO mineralization by an ATO-oxidizing enrichment. Complete biodegradation relied on switching redox conditions. The results provide the basis for designing consortia to treat mixtures of IMCs and related waste products by incorporating microbes with the required catabolic capabilities.
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Affiliation(s)
- Osmar Menezes
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Cameron Owens
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, Florida, USA
| | - Erika E Rios-Valenciana
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Jim A Field
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
| | - Jim C Spain
- Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, Florida, USA.,School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
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Elijah Akanbi O, Kim I, Cha DK, Attavane AA, Hubbard BP, Chiu PC. A Synergistic Nano‐Zerovalent Iron‐Hydrogen Peroxide Technology for Insensitive Munitions Wastewater Treatment. PROPELLANTS EXPLOSIVES PYROTECHNICS 2022. [DOI: 10.1002/prep.202100300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Inyoung Kim
- Department of Civil and Environmental Engineering University of Delaware Newark DE 19716 USA
| | - Daniel K. Cha
- Department of Civil and Environmental Engineering University of Delaware Newark DE 19716 USA
| | - Adithya A. Attavane
- U. S. Army Combat Capabilities Development Command Armaments Center Picatinny Arsenal NJ 07806 USA
| | - Brian P. Hubbard
- U. S. Army Joint Program Executive Office Armaments & Ammunition Picatinny Arsenal NJ 07806 USA
| | - Pei C. Chiu
- Department of Civil and Environmental Engineering University of Delaware Newark DE 19716 USA
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5
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Persico F, Temple T, Ladyman M, Gilroy‐Hirst W, Guiterrez‐Carazo E, Coulon F. Quantitative Environmental Assessment of Explosive Residues from the Detonation of Insensitive High Explosive Filled 155 mm Artillery Shell. PROPELLANTS EXPLOSIVES PYROTECHNICS 2022. [DOI: 10.1002/prep.202100220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Federica Persico
- Centre for Defence Chemistry Cranfield University Defence Academy of the United Kingdom Shrivenham SN6 7LA UK
| | - Tracey Temple
- Centre for Defence Chemistry Cranfield University Defence Academy of the United Kingdom Shrivenham SN6 7LA UK
| | - Melissa Ladyman
- Centre for Defence Chemistry Cranfield University Defence Academy of the United Kingdom Shrivenham SN6 7LA UK
| | - William Gilroy‐Hirst
- Centre for Defence Chemistry Cranfield University Defence Academy of the United Kingdom Shrivenham SN6 7LA UK
| | - Encina Guiterrez‐Carazo
- Centre for Defence Chemistry Cranfield University Defence Academy of the United Kingdom Shrivenham SN6 7LA UK
| | - Frederic Coulon
- School of Water Energy and Environment Cranfield University Cranfield MK43 0AL UK
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Madeira CL, Menezes O, Park D, Jog KV, Hatt JK, Gavazza S, Krzmarzick MJ, Sierra-Alvarez R, Spain JC, Konstantinidis KT, Field JA. Bacteria Make a Living Breathing the Nitroheterocyclic Insensitive Munitions Compound 3-Nitro-1,2,4-triazol-5-one (NTO). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5806-5814. [PMID: 33835790 DOI: 10.1021/acs.est.0c07161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The nitroheterocyclic 3-nitro-1,2,4-triazol-5-one (NTO) is an ingredient of insensitive explosives increasingly used by the military, becoming an emergent environmental pollutant. Cometabolic biotransformation of NTO occurs in mixed microbial cultures in soils and sludges with excess electron-donating substrates. Herein, we present the unusual energy-yielding metabolic process of NTO respiration, in which the NTO reduction to 3-amino-1,2,4-triazol-5-one (ATO) is linked to the anoxic acetate oxidation to CO2 by a culture enriched from municipal anaerobic digester sludge. Cell growth was observed simultaneously with NTO reduction, whereas the culture was unable to grow in the presence of acetate only. Extremely low concentrations (0.06 mg L-1) of the uncoupler carbonyl cyanide m-chlorophenyl hydrazone inhibited NTO reduction, indicating that the process was linked to respiration. The ultimate evidence of NTO respiration was adenosine triphosphate production due to simultaneous exposure to NTO and acetate. Metagenome sequencing revealed that the main microorganisms (and relative abundances) were Geobacter anodireducens (89.3%) and Thauera sp. (5.5%). This study is the first description of a nitroheterocyclic compound being reduced by anaerobic respiration, shedding light on creative microbial processes that enable bacteria to make a living reducing NTO.
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Affiliation(s)
- Camila L Madeira
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721-0011, United States
| | - Osmar Menezes
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721-0011, United States
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, Pernambuco 50740-530, Brazil
| | - Doyoung Park
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0355, United States
| | - Kalyani V Jog
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721-0011, United States
| | - Janet K Hatt
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0355, United States
| | - Savia Gavazza
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, Pernambuco 50740-530, Brazil
| | - Mark J Krzmarzick
- School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721-0011, United States
| | - Jim C Spain
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0355, United States
- Center for Environmental Diagnostics & Bioremediation, University of West Florida, Pensacola, Florida 32514, United States
| | - Konstantinos T Konstantinidis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0355, United States
| | - Jim A Field
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721-0011, United States
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Lent EM, Narizzano AM, Koistinen KA, Johnson MS. Chronic oral toxicity of 3-nitro-1,2,4-triazol-5-one (NTO) in rats. Regul Toxicol Pharmacol 2020; 112:104609. [PMID: 32027946 DOI: 10.1016/j.yrtph.2020.104609] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/27/2020] [Accepted: 02/01/2020] [Indexed: 01/08/2023]
Abstract
To evaluate the effects of chronic exposure to 3-nitro-1,2,4-triazol-5-one (nitrotriazolone, NTO), male and female rats were given ad libitum access to NTO in drinking water at concentrations of 0, 36, 110, 360, 1100, and 3600 mg/L for one year. NTO did not affect body weight, body weight gain, or food consumption in either sex. No treatment-related effects were observed in clinical chemistry and hematology parameters at the 6 month or one year sampling. At both the interim and final sampling, males and females from the 3600 mg/L group produced smaller volumes of urine that was darker, more concentrated, and contained more bilirubin than the controls. Total and motile sperm counts were not affected by NTO treatment. Absolute and relative organ weights did not differ between control and NTO treated groups for either sex. Spontaneous age-related neoplasms occurred in controls and NTO groups at rates consistent with published historic controls. NTO was generally non-toxic in females at the doses tested. Toxicity in males was limited to testicular toxicity as demonstrated in previous studies. Chronic exposure did not result in testicular toxicity at lower doses and the toxicity observed only in the high dose group in this study is less severe than that observed in shorter exposures of previous studies, suggesting differences may be associated with influences of study design on kinetics. A Benchmark Dose (BMD) of 1604 mg/L (76 mg/kg-day) and a Benchmark Dose Lower Bound (BMDL10) of 921 mg/L (44 mg/kg-day) were determined for chronic effects of NTO in male rats.
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Affiliation(s)
- Emily May Lent
- Toxicology Directorate. Army Public Health Center, Aberdeen Proving Ground, MD, USA.
| | - Allison M Narizzano
- Toxicology Directorate. Army Public Health Center, Aberdeen Proving Ground, MD, USA
| | - Keith A Koistinen
- Toxicology Directorate. Army Public Health Center, Aberdeen Proving Ground, MD, USA
| | - Mark S Johnson
- Toxicology Directorate. Army Public Health Center, Aberdeen Proving Ground, MD, USA
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8
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Gust KA, Lotufo GR, Thiyagarajah A, Barker ND, Ji Q, Marshall K, Wilbanks MS, Chappell P. Molecular Evaluation of Impacted Reproductive Physiology in Fathead Minnow Testes Provides Mechanistic Insights into Insensitive Munitions Toxicology. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 213:105204. [PMID: 31185427 DOI: 10.1016/j.aquatox.2019.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/13/2019] [Accepted: 05/13/2019] [Indexed: 06/09/2023]
Abstract
Previous toxicological investigations of the insensitive munition (IM), 3-nitro-1,2,4-triazol-5-one (NTO), demonstrated histopathological and physiological impacts in mammalian testes. The implications of these findings for fish was unknown, therefore we investigated the effects of chronic (21 day) exposures to NTO and an NTO-containing IM formulation called IMX-101 (composed of 2,4-dinitroanisole (DNAN), nitroguanidine (NQ), and NTO) in adult male fathead minnows to assess if impacts on testes were conserved. The NTO exposure caused no significant mortality through the maximum exposure concentration (720 mg/L, measured), however NTO elicited testicular impacts causing significant asynchrony in spermatogenesis and necrosis in secondary spermatocytes at the two highest exposure concentrations (383 mg/L and 720 mg/L) and testicular degeneration at the highest exposure. Microarray-based transcriptomics analysis identified significant enrichment of steroid metabolism pathways and mTORC-signal control of spermatogonia differentiation in NTO exposures each having logical connections to observed asynchronous spermatogenesis. Additionally, NTO impaired transcriptional expression for genes supporting sperm structural and flagellar development including sperm-associated antigen 6 (Spag6). These functional transcriptomic responses are hypothesized contributors to impacted reproductive physiology in NTO exposures that ultimately lead to reductions in spermatozoa. In contrast to NTO, the IMX-101 formulation elicited significant mortality at the two highest exposure concentrations of 25.2 and 50.9 mg/L (DNAN nominal + NTO measured + NQ measured). Unlike NTO and NQ, the DNAN component of the IMX-101 formulation underwent significant transformation in the 21d exposure. From previous investigations, neither NTO nor NQ caused mortality in fish at >1000 mg/L suggesting that mortality in the present study arose from DNAN / DNAN-attributable transformation products. The 12.6 mg/L IMX-101 exposure caused significant sublethal impacts on testes including sperm necrosis, interstitial fibrosis, and Sertoli-like cell hyperplasia. Transcriptional profiles for IMX-101 indicated significant enrichment on multiple signaling pathways supporting spermatogenesis, mitosis / meiosis, and flagellar structure, all logically connected to observed sperm necrosis. Additionally, pronounced transcriptional increases within the PPARα-RXRα pathway, a known DNAN target, has been hypothesized to correspond to Sertoli cell hyperplasia, presumably as a compensatory response to fulfill the nurse-function of Sertoli cells during spermatogenesis. Overall, the transcriptional results indicated unique molecular responses for NTO and IMX-101. Regarding chemical hazard, NTO impacted testes and impaired spermatogenesis, but at high exposure concentrations (≥ 192 mg/L), whereas the IMX-101 formulation, elicited mortality and impacts on reproductive physiology likely caused by DNAN and its transformation products present at concentrations well below the NTO-component concentration within the IMX-101 mixture formulation.
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Affiliation(s)
- Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi, USA.
| | - Guilherme R Lotufo
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi, USA.
| | | | | | - Qing Ji
- Bennett Aerospace, Cary, NC, 27511, USA.
| | | | - Mitchell S Wilbanks
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi, USA.
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Gong P, Donohue KB, Mayo AM, Wang Y, Hong H, Wilbanks MS, Barker ND, Guan X, Gust KA. Comparative toxicogenomics of three insensitive munitions constituents 2,4-dinitroanisole, nitroguanidine and nitrotriazolone in the soil nematode Caenorhabditis elegans. BMC SYSTEMS BIOLOGY 2018; 12:92. [PMID: 30547801 PMCID: PMC6293504 DOI: 10.1186/s12918-018-0636-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Ecotoxicological studies on the insensitive munitions formulation IMX-101 and its components 2,4-dinitroanisole (DNAN), nitroguanidine (NQ) and nitrotriazolone (NTO) in various organisms showed that DNAN was the main contributor to the overall toxicity of IMX-101 and suggested that the three compounds acted independently. These results motivated this toxicogenomics study to discern toxicological mechanisms for these compounds at the molecular level. METHODS Here we used the soil nematode Caenorhabditis elegans, a well-characterized genomics model, as the test organism and a species-specific, transcriptome-wide 44 K-oligo probe microarray for gene expression analysis. In addition to the control treatment, C. elegans were exposed for 24 h to 6 concentrations of DNAN (1.95-62.5 ppm) or NQ (83-2667 ppm) or 5 concentrations of NTO (187-3000 ppm) with ten replicates per treatment. The nematodes were transferred to a clean environment after exposure. Reproduction endpoints (egg and larvae counts) were measured at three time points (i.e., 24-, 48- and 72-h). Gene expression profiling was performed immediately after 24-h exposure to each chemical at the lowest, medium and highest concentrations plus the control with four replicates per treatment. RESULTS Statistical analyses indicated that chemical treatment did not significantly affect nematode reproduction but did induce 2175, 378, and 118 differentially expressed genes (DEGs) in NQ-, DNAN-, and NTO-treated nematodes, respectively. Bioinformatic analysis indicated that the three compounds shared both DEGs and DEG-mapped Reactome pathways. Gene set enrichment analysis further demonstrated that DNAN and NTO significantly altered 12 and 6 KEGG pathways, separately, with three pathways in common. NTO mainly affected carbohydrate, amino acid and xenobiotics metabolism while DNAN disrupted protein processing, ABC transporters and several signal transduction pathways. NQ-induced DEGs were mapped to a wide variety of metabolism, cell cycle, immune system and extracellular matrix organization pathways. CONCLUSION Despite the absence of significant effects on apical reproduction endpoints, DNAN, NTO and NQ caused significant alterations in gene expression and pathways at 1.95 ppm, 187 ppm and 83 ppm, respectively. This study provided supporting evidence that the three chemicals may exert independent toxicity by acting on distinct molecular targets and pathways.
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Affiliation(s)
- Ping Gong
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
| | - Keri B Donohue
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Anne M Mayo
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Yuping Wang
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Huixiao Hong
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, 72079, USA
| | - Mitchell S Wilbanks
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Natalie D Barker
- Bennett Aerospace Inc., 1249 Kildaire Farm Road, Cary, NC, 27511, USA
| | - Xin Guan
- Bennett Aerospace Inc., 1249 Kildaire Farm Road, Cary, NC, 27511, USA
| | - Kurt A Gust
- Environmental Laboratory, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
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Lent EM, Mullins AB, May AD, Honnold CL, Despain KE. Characterization of the Testicular Toxicity of 3-Nitro-1,2,4-Triazol-5-One and 2,4-Dinitroanisole in Rats (Rattus norvegicus). Int J Toxicol 2018; 37:364-372. [DOI: 10.1177/1091581818789878] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nitrotriazolone (3-nitro-1,2,4-triazol-5-one; NTO) and dinitroanisole (2,4-dinitroanisole; DNAN), insensitive energetic materials used in explosive formulations, have induced testicular toxicity and oligospermia in repeated-dose oral toxicity tests. To identify the target site of testicular toxicity of NTO and DNAN, Sprague Dawley rats were orally dosed with NTO (500 mg/kg/d) or DNAN (50 or 100 mg/kg/d) in corn oil for 1, 3, 7, or 14 days. Degeneration of germinal epithelium occurred in multiple tubule stages on days 7 and 14 in treated rats. Degeneration increased in severity with time and was characterized by degeneration/apoptosis of pachytene spermatocytes and round and elongating spermatids, depletion of step 19 spermatids, luminal spermatogenic cell sloughing, multinucleate cells, and pronounced Sertoli cell vacuolation. Serum luteinizing hormone and follicle-stimulating hormone did not differ between NTO- and DNAN-treated and control rats on any sampling day. Serum testosterone levels reduced only in rats given 50 mg/kg/d DNAN for 7 days. These results suggest that the initial site of testicular injury for both NTO and DNAN is the Sertoli cell.
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Affiliation(s)
- Emily May Lent
- Army Public Health Center, Aberdeen Proving Ground, MD, USA
| | - Anna B. Mullins
- Uniformed Services University of Health Sciences, Bethesda, MD, USA
| | | | - Cary L. Honnold
- US Army Medical Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Kenneth E. Despain
- US Army Medical Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
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Jackovitz AM, Koistinen KA, Lent EM, Bannon DI, Quinn MJ, Johnson MS. Neuromuscular anomalies following oral exposure to 3-nitro-1,2,4-triazol-5-one (NTO) in a one-generation study with Japanese quail (Coturnix japonica). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2018; 81:718-733. [PMID: 29939830 DOI: 10.1080/15287394.2018.1485123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Substances used as explosives in munitions by the military often result in environmental releases through manufacturing, testing, training, and combat activities. The toxicity of 3-nitro-1,2,4-triazol-5-one (nitrotriazolone or NTO) was evaluated following oral exposure in Japanese quail (Coturnix japonica) to determine if environmental releases result in unacceptable risks to avian populations. In an acute test at the limit dose (2000 mg/kg), one female was ataxic, exhibited tremors, and showed signs of neurological toxicity approximately 24 h after dosing. In a subsequent one-generation study, parental generation (F0) birds were exposed orally to 1000, 500, 100, or 20mg/kg-day NTO suspended in corn oil. After 5 consecutive days of dosing, 2-week-old birds receiving 1000 mg/kg-day displayed ataxia, convulsions, backward arching of the neck (opisthotonos), and alternated between prostrate inactivity and ataxic wing activity. Birds in the 500 mg/kg-day group exhibited neuromuscular anomalies after 17 days exposure. Ultimately, all of the 1000 mg/kg-day birds and all but one of the 500 mg/kg-day birds met euthanasia criteria and were humanely euthanized prior to behavioral and reproductive evaluation. As such, first-generation (F1) birds were exposed to 100 or 20 mg/kg-day NTO. Mild neuromuscular anomalies occurred in 10% of F1 birds from the 100 mg/kg-day group, but not in birds from 20 mg/kg-day or controls in either generation. Vacuolization of cerebellum and/or the brainstem was observed on histopathologic examination in a dose-dependent manner. Therefore, brain vacuoles and neuromuscular anomalies were identified as critical endpoints in this study. A mean Benchmark Dose (BMD) for brain vacuoles of 62 mg/kg-day was derived for male and female F0-generation quail, which corresponded to a Benchmark Dose Low (BMDL10) of 35 mg/kg-day.
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Affiliation(s)
| | | | - Emily M Lent
- a Toxicology Directorate, Army Public Health Center , MD , USA
| | | | - Michael J Quinn
- a Toxicology Directorate, Army Public Health Center , MD , USA
| | - Mark S Johnson
- a Toxicology Directorate, Army Public Health Center , MD , USA
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Temple T, Ladyman M, Mai N, Galante E, Ricamora M, Shirazi R, Coulon F. Investigation into the environmental fate of the combined Insensitive High Explosive constituents 2,4-dinitroanisole (DNAN), 1-nitroguanidine (NQ) and nitrotriazolone (NTO) in soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:1264-1271. [PMID: 29996423 DOI: 10.1016/j.scitotenv.2017.12.264] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/28/2017] [Accepted: 12/21/2017] [Indexed: 06/08/2023]
Abstract
Contamination of military ranges by the use of explosives can lead to irreversible environmental damage, specifically to soil and groundwater. The fate and effects of traditional explosive residues are well understood, while less is known about the impact of Insensitive High Explosives (IHEs) that are currently being brought into military service. Current research has focussed on the investigation of individual constituents of IHE formulations, which may not be representative of real-world scenarios when explosive residues will be deposited together. Therefore, this study investigated the fate and transport of the combined IHE constituents 2,4-dinitroanisole (DNAN), 1-nitroguanidine (NQ) and 3-nitro-1,2,4-triazol-5-one (NTO) in two UK soil types. Static experiments ran for 9weeks to determine the fate of the combined explosive constituents in soil by monitoring the rate of degradation. Transport was examined by running soil column experiments for 5weeks, with a watering regime equivalent to the average yearly UK rainfall. Both static and soil column experiments confirmed that DNAN and NTO started to degrade within twenty-four hours in soil with high organic content, and were both completely degraded within sixty days. NQ was more stable, with 80% of the original material recovered after sixty days. The major degradation product of DNAN in the test soils was 2-amino-4-nitroanisole (2-ANAN), with trace amounts of 4-amino-2-nitroanisole. NTO was rapidly degraded in soil with high organic content, although no degradation products were identified. Results supported work from literature on the individual constituents DNAN, NQ and NTO suggesting that the three explosives in combination did not interact with each other when in soil. This study should provide a useful insight into the behaviour of three combined Insensitive High Explosive constituents for the predication of soil and water contamination during military training.
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Affiliation(s)
- T Temple
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK.
| | - M Ladyman
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - N Mai
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - E Galante
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - M Ricamora
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - R Shirazi
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - F Coulon
- Cranfield University, School of Water, Energy and Environment, Cranfield MK43 0AL, UK
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Pillard DA, Eck WS, Johnson MS, Packard S. Effects of 3-Nitro-1,2,4-triazol-5-one on Survival, Growth and Metamorphosis in the Northern Leopard Frog, Lithobates pipiens. ECOTOXICOLOGY (LONDON, ENGLAND) 2017; 26:1170-1180. [PMID: 28801886 DOI: 10.1007/s10646-017-1842-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/26/2017] [Indexed: 06/07/2023]
Abstract
New explosive formulations are being developed to be less sensitive to impact and inadvertent explosion, increasing safety for the warfighter. Since testing and training make environmental releases imminent, the toxicity of 3-nitro-1,2,4-triazol-5-one (NTO), a component of Insensitive Munitions eXplosive (IMX) formulations, was assessed in a one-generation study to the northern leopard frog (Lithobates ( = Rana) pipiens). Because NTO in water creates acidic conditions, acute studies were conducted with non-pH-adjusted NTO, while a long-term (70-d) study was conducted with neutralized NTO. In the acute study, 48-h and 7-d LC50s were ~250 mg NTO/L. In the long-term study, tadpoles were dead by day 2 in 11,350 mg/L NTO, and by day 63 in 8382 mg/L. The 70-d LC50 was 3670 mg (neutralized) NTO/L. The number of organisms reaching complete metamorphosis was reduced by NTO; the lowest IC25 was 1999 mg NTO/L for the Number Completing Metamorphosis. The NOECs for Time to Front Limb Eruption or Time to Metamorphosis were the same at 1346 mg/L. Histopathology did not significantly distinguish between NTO-exposed and unexposed animals, although possible effects on the density of spermatogonia in NTO-exposed males was suggested. The test data indicate that acute toxicity to ambient NTO can be attributed primarily to its acidic nature; relatively low chronic toxicity of neutralized NTO is due to delays in metamorphosis. The consequence from this latter observation may be ecologically significant as delays of even a few days could increase mortality through predation and/or loss of the aquatic medium in temporary water bodies.
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Affiliation(s)
| | - William S Eck
- US Army Public Health Center, Army Institute of Public Health, Aberdeen Proving Ground, Aberdeen, MD, USA
| | - Mark S Johnson
- US Army Public Health Center, Army Institute of Public Health, Aberdeen Proving Ground, Aberdeen, MD, USA
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Madeira CL, Speet SA, Nieto CA, Abrell L, Chorover J, Sierra-Alvarez R, Field JA. Sequential anaerobic-aerobic biodegradation of emerging insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO). CHEMOSPHERE 2017; 167:478-484. [PMID: 27750172 PMCID: PMC5605804 DOI: 10.1016/j.chemosphere.2016.10.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/07/2016] [Accepted: 10/10/2016] [Indexed: 05/25/2023]
Abstract
Insensitive munitions, such as 3-nitro-1,2,4-triazol-5-one (NTO), are being considered by the U.S. Army as replacements for conventional explosives. Environmental emissions of NTO are expected to increase as its use becomes widespread; but only a few studies have considered the remediation of NTO-contaminated sites. In this study, sequential anaerobic-aerobic biodegradation of NTO was investigated in bioreactors using soil as inoculum. Batch bioassays confirmed microbial reduction of NTO under anaerobic conditions to 3-amino-1,2,4-triazol-5-one (ATO) using pyruvate as electron-donating cosubstrate. However, ATO biodegradation was only observed after the redox condition was switched to aerobic. This study also demonstrated that the high-rate removal of NTO in contaminated water can be attained in a continuous-flow aerated bioreactor. The reactor was first fed ATO as sole energy and nitrogen source prior to NTO addition. After few days, ATO was removed in a sustained fashion by 100%. When NTO was introduced together with electron-donor (pyruvate), NTO degradation increased progressively, reaching a removal efficiency of 93.5%. Mineralization of NTO was evidenced by the partial release of inorganic nitrogen species in the effluent, and lack of ATO accumulation. A plausible hypothesis for these findings is that NTO reduction occurred in anaerobic zones of the biofilm whereas ATO was mineralized in the bulk aerobic zones of the reactor.
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Affiliation(s)
- Camila L Madeira
- Department of Chemical & Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0011, USA.
| | - Samuel A Speet
- Department of Chemical & Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0011, USA
| | - Cristina A Nieto
- Department of Chemical & Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0011, USA
| | - Leif Abrell
- Department of Soil, Water & Environmental Science, University of Arizona, P.O. Box 210038, Tucson, AZ 85721-0038, USA; Departments of Chemistry & Biochemistry, University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0041, USA
| | - Jon Chorover
- Department of Soil, Water & Environmental Science, University of Arizona, P.O. Box 210038, Tucson, AZ 85721-0038, USA
| | - Reyes Sierra-Alvarez
- Department of Chemical & Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0011, USA
| | - Jim A Field
- Department of Chemical & Environmental Engineering, University of Arizona, P.O. Box 210011, Tucson, AZ 85721-0011, USA
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Lent EM, Crouse LCB, Jackovitz AM, Carroll EE, Johnson MS. An extended one-generation reproductive toxicity test of 1,2,4-Triazol-5-one (NTO) in rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 79:1159-1178. [PMID: 27754820 DOI: 10.1080/15287394.2016.1219893] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nitrotriazolone (1,2,4-triazol-5-one; NTO), an insensitive, energetic material used in explosive formulations, induced testicular toxicity and oligospermia in repeated-dose oral toxicity tests in rats. To evaluate whether NTO produces additional reproductive and developmental effects, a modified extended one-generation reproductive toxicity test was conducted. Rats were provided ad libitum access to NTO in drinking water at 0-, 144-, 720-, or 3600-mg/L NTO. Treatment of the parental generation began 2 (females) and 4 (males) wk premating and continued until weaning of litters. Direct dosing of offspring (F1) occurred from weaning through puberty. Pups were counted and weighed on postnatal day (PND) 0/1. Anogenital distance (AGD) was measured on PND 4 and males were examined for presence of nipples on PND 13. F1 offspring were examined daily for attainment of puberty. NTO did not markedly affect measures of fertility, including mating indices, gestation index, litter size, and sex ratio. Seminiferous tubule degeneration or atrophy was observed in P1 and F1 3600-mg/L NTO males. F1 males in the 3600 mg/L group exhibited reduced reproductive organ mass (testes, epididymides, and accessory sex organs). Nipple retention was increased in NTO exposed F1 males compared to controls. Attainment of puberty was delayed by 2.6 d in the 3600-mg/L NTO-exposed males relative to controls. Comparison of the effects of NTO with those of antiandrogens suggests absence of malformations of the genital tract in NTO-exposed males. This study supports previous findings indicating that NTO is a testicular toxicant with male developmental effects that may be secondary to testicular toxicity.
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Affiliation(s)
- Emily May Lent
- a Toxicology Directorate , U.S. Army Public Health Center , Aberdeen Proving Ground , Maryland , USA
| | - Lee C B Crouse
- a Toxicology Directorate , U.S. Army Public Health Center , Aberdeen Proving Ground , Maryland , USA
| | - Allison M Jackovitz
- a Toxicology Directorate , U.S. Army Public Health Center , Aberdeen Proving Ground , Maryland , USA
| | - Erica E Carroll
- a Toxicology Directorate , U.S. Army Public Health Center , Aberdeen Proving Ground , Maryland , USA
| | - Mark S Johnson
- a Toxicology Directorate , U.S. Army Public Health Center , Aberdeen Proving Ground , Maryland , USA
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Mullins AB, Despain KE, Wallace SM, Honnold CL, May Lent E. Testicular effects of 3-nitro-1,2,4-triazol-5-one (NTO) in mice when exposed orally. Toxicol Mech Methods 2016; 26:97-103. [DOI: 10.3109/15376516.2015.1118175] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Anna B. Mullins
- Veterinary Services Program, Walter Reed Army Institute of Research/Naval Medical Research Center, Silver Spring, MD, USA and
| | - Kenneth E. Despain
- Veterinary Services Program, Walter Reed Army Institute of Research/Naval Medical Research Center, Silver Spring, MD, USA and
| | - Shannon M. Wallace
- Veterinary Services Program, Walter Reed Army Institute of Research/Naval Medical Research Center, Silver Spring, MD, USA and
| | - Cary L. Honnold
- Veterinary Services Program, Walter Reed Army Institute of Research/Naval Medical Research Center, Silver Spring, MD, USA and
| | - Emily May Lent
- U.S. Army Public Health Command, Army Institute of Public Health, Aberdeen Proving Ground, MD, USA
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Lent EM, Crouse LC, Wallace SM, Carroll EE. Peri-pubertal administration of 3-nitro-1,2,4-triazol-5-one (NTO) affects reproductive organ development in male but not female Sprague Dawley rats. Reprod Toxicol 2015; 57:1-9. [DOI: 10.1016/j.reprotox.2015.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/19/2015] [Accepted: 04/29/2015] [Indexed: 11/17/2022]
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Sweeney LM, Phillips EA, Goodwin MR, Bannon DI. Toxicokinetic Model Development for the Insensitive Munitions Component 3-Nitro-1,2,4-Triazol-5-One. Int J Toxicol 2015; 34:408-16. [PMID: 26060267 DOI: 10.1177/1091581815589000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
3-Nitro-1,2,4-triazol-5-one (NTO) is a component of insensitive munitions that are potential replacements for conventional explosives. Toxicokinetic data can aid in the interpretation of toxicity studies and interspecies extrapolation, but only limited data on the toxicokinetics and metabolism of NTO are available. To supplement these limited data, further in vivo studies of NTO in rats were conducted and blood concentrations were measured, tissue distribution of NTO was estimated using an in silico method, and physiologically based pharmacokinetic models of the disposition of NTO in rats and macaques were developed and extrapolated to humans. The model predictions can be used to extrapolate from designated points of departure identified from rat toxicology studies to provide a scientific basis for estimates of acceptable human exposure levels for NTO.
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Affiliation(s)
- Lisa M Sweeney
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Naval Medical Research Unit Dayton (NAMRU-D), Wright Patterson Air Force Base, OH, USA
| | | | | | - Desmond I Bannon
- US Army Public Health Command, Institute of Public Health, Toxicology Portfolio, Aberdeen Proving Ground, MD, USA
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