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Yang N, Wu T, Bao X, Ma T, Huang Y, Liu D, Gong X, Wang YA, Xu S, Zhou B. Exploring the thermal decomposition and detonation mechanisms of 2,4-dinitroanisole by TG-FTIR-MS and molecular simulations. RSC Adv 2024; 14:11429-11442. [PMID: 38595715 PMCID: PMC11003239 DOI: 10.1039/d4ra00860j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/27/2024] [Indexed: 04/11/2024] Open
Abstract
2,4-dinitroanisole (DNAN), an insensitive explosive, has replaced trinitrotoluene (TNT) in many melt-cast explosives to improve the safety of ammunition and becomes a promising material to desensitize novel explosives of high sensitivity. Here, we combine thermogravimetric-Fourier transform infrared spectrometry-Mass spectrometry (TG-FTIR-MS), density functional theory (DFT), and ReaxFF molecular dynamics (MD) to investigate its thermal decomposition and detonation mechanisms. As revealed by TG-FTIR-MS, the thermal decomposition of DNAN starts at ca. 453 K when highly active NO2 is produced and quickly converted to NO resulting in the formation of a large amount of Ph(OH)(OH2)OCH3+. DFT calculations show that the activation energy of DNAN is higher than that of TNT due to the lack of α-H. Further steps in both thermal decomposition and detonation reactions of the DNAN are dominated by bimolecular O-transfers. ReaxFF MD indicates that DNAN has a lower heat of explosion than TNT, in accordance with the observation that the activation energies of polynitroaromatic explosives are inversely proportional to their heat of explosion. The inactive -OCH3 group and less nitro groups also render DNAN higher thermal stability than TNT.
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Affiliation(s)
- Nian Yang
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Tianlong Wu
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Xiaofang Bao
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Teng Ma
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Yinsheng Huang
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Dabin Liu
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Xuedong Gong
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Yan A Wang
- Department of Chemistry, University of British Columbia Vancouver British Columbia V6T 1Z1 Canada
| | - Sen Xu
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
| | - Baojing Zhou
- School of Chemistry and Chemical Engineering, Nanjing University of Science & Technology Nanjing 210094 China
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Gutierrez-Carazo E, Dowle J, Coulon F, Temple T, Ladyman M. Investigating residue dissolution of insensitive high explosives in two sandy soil types: A predictive modelling approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166968. [PMID: 37704157 DOI: 10.1016/j.scitotenv.2023.166968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023]
Abstract
The demand for munitions that are less likely to detonate accidentally has led to an increased use of Insensitive High Explosives (IHE), which contain substances like 2,4-dinitroanisole (DNAN) and 5-nitro-1,2,4-triazol-3-one (NTO). These substances have different properties compared to traditional explosives, and their potential environmental impact is not well understood. When these explosives are used in live-fire training exercises, their residues end up in the soil. It is important to determine how these residues dissolve and enter the soil. This study aimed to experimentally measure the rate at which an IHE formulation dissolves when exposed to rainwater with pH levels of 5.0 and 6.5, and to simulate how these residues dissolve and move through two different soil types. The dissolution rates were determined by conducting experiments in which IHE particles (30-60 mg) were exposed to water with varying pH levels and temperatures. The results showed that the dissolution rate of NTO did not vary with pH, while the dissolution rate of DNAN and RDX decreased with decreasing pH. Specifically, the dissolution rate of DNAN decreased from 18 ± 40 μg min-1 at pH 6.5 to 6 ± 4 μg min-1 at pH 5.0, while the dissolution rate of RDX decreased from 8 ± 4 to 3 ± 1 μg min-1. These findings were used to develop a stochastic model that successfully simulated the concentration of IHE in the leachate from soil columns over time. A sensitivity analysis revealed that while dissolution rates determined the amount of mass entering the soil, they did not significantly regulate the amount of mass that migrated through the soil and leached out of the soil columns.
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Affiliation(s)
- Encina Gutierrez-Carazo
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - James Dowle
- Golder, Sirius Building, The Clocktower, Edinburgh EH12 9LB, UK
| | - Frederic Coulon
- Cranfield University, School of Water, Energy and Environment, Cranfield MK43 0AL, UK
| | - Tracey Temple
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - Melissa Ladyman
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK.
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3
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Mai A, Hadnagy E, Shi Q, Ezeonu L, Robbins JP, Podkolzin SG, Koutsospyros A, Christodoulatos C. Degradation and fate of 2,4-dinitroanisole (DNAN) and its intermediates treated with Mg/Cu bimetal: Surface examination with XAS, DFT, and LDI-MS. J Environ Sci (China) 2023; 129:161-173. [PMID: 36804233 DOI: 10.1016/j.jes.2022.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 06/18/2023]
Abstract
A novel Mg-based bimetal reagent (Mg/Cu) was used as an enhanced reductive system to degrade insensitive munition 2,4-dinitroanisole (DNAN), a contaminant found in energetic-laden waste. Degradation of DNAN was significantly impacted by dissolved oxygen and studied in anoxic and oxic bimetal systems (i.e., purging with N2, air, or O2 gas). Degradation occurred through sequential nitroreduction: first one nitro group was reduced (ortho or para) to form short-lived intermediates 2-amino-4-nitroanisole or 4-amino-2-nitroanisole (2-ANAN or 4-ANAN), and then subsequent reduction of the other nitro group formed 2,4-diaminoanisole (DAAN). The nitro-amino intermediates demonstrated regioselective reduction in the ortho position to 2-ANAN; Regioselectivity was also impacted by the anoxic/oxic environment. Under O2-purging DNAN degradation rate was slightly enhanced, but most notably O2 significantly accelerated DAAN generation. DAAN also further degraded only in the oxygenated Mg/Cu system. Adsorption of DNAN byproducts to the reagent occurred regardless of anoxic/oxic condition, resulting in a partition of carbon mass between the adsorbed phase (27%-35%) and dissolved phase (59%-72%). Additional surface techniques were applied to investigate contaminant interaction with Cu. Density functional theory (DFT) calculations identified preferential adsorption structures for DNAN on Cu with binding through two O atoms of one or both nitro groups. X-ray absorption spectroscopy (XAS) measurements determined the oxidation state of catalytic metal Cu and formation of a Cu-O-N bond during treatment. Laser desorption ionization mass spectrometry (LDI-MS) measurements also identified intermediate 2-ANAN adsorbed to the bimetal surface.
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Affiliation(s)
- Andrew Mai
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA.
| | - Emese Hadnagy
- School of Engineering and Technology, University of Washington Tacoma, Tacoma, WA 98402, USA
| | - Qiantao Shi
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Lotanna Ezeonu
- School of Engineering and Technology, University of Washington Tacoma, Tacoma, WA 98402, USA
| | - Jason P Robbins
- School of Engineering and Technology, University of Washington Tacoma, Tacoma, WA 98402, USA
| | - Simon G Podkolzin
- School of Engineering and Technology, University of Washington Tacoma, Tacoma, WA 98402, USA
| | - Agamemnon Koutsospyros
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA
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Polyakov V, Kadoya W, Beal S, Morehead H, Hunt E, Cubello F, Meding SM, Dontsova K. Transport of insensitive munitions constituents, NTO, DNAN, RDX, and HMX in runoff and sediment under simulated rainfall. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161434. [PMID: 36623648 DOI: 10.1016/j.scitotenv.2023.161434] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Insensitive munition constituents derived from residues of low order detonations and deposited on military training grounds present environmental risks. A series of rainfall simulation experiments on small soil plots examined the effect of precipitation, soil properties, and particle size on transport of IMX-104 munition components: NTO (3-nitro-1,2,4-triazol-5-one), DNAN (2,4-dinitroanisole), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and HMX (octahydro-1,3,5,7- tertranitro-1,3,5,7-tetrazocine). The primary pathways for rainfall driven transport were subsurface infiltration, off-site transport in solution, and transport in solid form including re-adsorption onto soil particles. The transport was solubility dependent with NTO moving mostly in solution, which was dominated by either runoff or infiltration depending on soil. DNAN, RDX, and HMX, were transported primarily in particulate form. The fine energetic fraction (<2 mm) showed the highest mobility, while the coarsest fraction (>4.75 mm) remained in-situ after rainfall. A simple linear model relating energetics transport with sediment yield and energetics particle size and was proposed. These findings provide the first comprehensive mass balance of munition constituents as affected by overland flow under rainfall. They improve our understanding of environmental fate of munitions, can further be used for predictive modelling, developing mitigation strategies, and regulatory compliance.
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Affiliation(s)
- Viktor Polyakov
- Southwest Watershed Research Center, USDA-ARS, 2000 E Allen Rd, Tucson, AZ 85718, USA.
| | - Warren Kadoya
- U.S. Army Engineer Research and Development Center, CRREL, 72 Lyme Road, Hanover, NH 03755-1290, USA
| | - Samuel Beal
- U.S. Army Engineer Research and Development Center, CRREL, 72 Lyme Road, Hanover, NH 03755-1290, USA
| | - Hayden Morehead
- Department of Environmental Science, The University of Arizona, 1177 E 4th St., Tucson, AZ 85721, USA
| | - Edward Hunt
- Biosphere 2, The University of Arizona, 32540 S Biosphere Rd, Oracle, AZ 85623, USA
| | - Favianna Cubello
- Department of Environmental Science, The University of Arizona, 1177 E 4th St., Tucson, AZ 85721, USA
| | | | - Katerina Dontsova
- Department of Environmental Science, The University of Arizona, 1177 E 4th St., Tucson, AZ 85721, USA; Biosphere 2, The University of Arizona, 32540 S Biosphere Rd, Oracle, AZ 85623, USA
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5
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Moores LC, Kennedy AJ, Rabalais L, Jones SJ, George GW, Zetterholm SG, Acrey B, Amar SK, Gust KA. Effect of UV-light exposure duration, light source, and aging on nitroguanidine (NQ) degradation product profile and toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153554. [PMID: 35131242 DOI: 10.1016/j.scitotenv.2022.153554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Previous studies have reported increased aquatic toxicity of UV-degraded nitroguanidine (NQ), but many details underlying the dynamics of NQ degradation and toxicity remain unknown. These data gaps represent critical barriers to assessing the environmental relevance of laboratory-generated UV-degradation results and extrapolation to environmental risk. In the present study, the toxicity of NQ increased with increasing proportional degradation of the parent compound. Specifically, while the LC50 of undegraded NQ was 1485 mg/L, the toxicity at the lowest degradation level examined (7% parent compound degraded) increased by nearly two-orders of magnitude (LC50 = 17.3 mg/L) and increased by nearly three-orders of magnitude (LC50 = 6.23 mg/L) in the highest percent NQ degradation (90%) treatment. Similar LC50 values between immediately tested and aged (8-13 days) NQ degradation products suggested the degradation product(s) causing the toxicity were stable, although concentrations of nitrite and nitrate increased after aging. Finally, experiments where NQ was degraded in natural sunlight confirmed increased toxicity in environmentally relevant D. pulex exposures; however, the two-order of magnitude increase in toxicity (LC50 = 21.3 mg/L) at 53% degradation was less than NQ degraded by a laboratory photoreactor by a similar percentage (46% degraded). Identification of principal toxic agents in the UV-degraded NQ product mixture remains a critical data gap. Mass balance calculations were generated for our experimental results and literature values revealing difficulty in accounting for all NQ degradation products. Products with suspected high potency in D. pulex were identified which require further testing including: nitrosoguanidine, nitrosourea, and hydroxylamine. SYNOPSIS: The toxicity of NQ increased with increasing UV-degradation where toxicity-inducing degradation products were stable over 1-2 weeks; increased toxicity was validated from natural-sunlight degradation of NQ, however toxicity was lower than UV-photoreactor degraded NQ; and the identity of specific toxic UV-degradation products remains elusive where carefully-designed mass-balance experiments and toxicity testing are needed to provide definitive identification.
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Affiliation(s)
- Lee C Moores
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, United States of America.
| | - Alan J Kennedy
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, United States of America
| | - Lauren Rabalais
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, United States of America
| | - Stacy J Jones
- HX5, 212 Eglin Parkway SE, Ft. Walton Beach, FL 32548, United States of America
| | - Garret W George
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, United States of America
| | - Sarah Grace Zetterholm
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, United States of America
| | - Brad Acrey
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Athens, GA 30605, United States of America
| | - Saroj Kumar Amar
- Oak Ridge Institute for Science and Education, Oak Ridge, TN 37831, United States of America
| | - Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, United States of America
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6
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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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7
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Qin C, Abrell L, Troya D, Hunt E, Taylor S, Dontsova K. Outdoor dissolution and photodegradation of insensitive munitions formulations IMX-101 and IMX-104: Photolytic transformation pathway and mechanism study. CHEMOSPHERE 2021; 280:130672. [PMID: 33964749 DOI: 10.1016/j.chemosphere.2021.130672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
New munition compounds have been developed to replace traditional explosives to prevent unintended detonations. However, insensitive munitions (IM) can leave large proportion of unexploded charge in the field, where it is subjected to photodegradation and dissolution in precipitation. The photolytic reactions occurring on the surfaces of IMX-101 and IMX-104 formulations and the subsequent fate of photolytic products in the environment were thoroughly investigated. The constituents of IMX-101 and IMX-104 formulations dissolve sequentially under rainfall in the order of aqueous solubility: 3-nitro-1,2,4-triazol-5-one (NTO) > nitroguanidine (NQ) > 2,4-dinitroanisole (DNAN) > 1,3,5-hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). A linear relationship between DNAN dissolution and rainwater volume was observed (r2: 0.86-0.99). It was estimated that it would take 16-228 years to completely dissolve these formulation particles under natural environmental conditions in Oracle, AZ. We used LC/MS/MS and GC/MS to examine the dissolution samples from IMX-101 and 104 particles exposed to rainfall and sunlight and found six DNAN photo-transformation products including 2-methoxy-5-nitrophenol, 4-methoxy-3-nitrophenol, 4-methoxy-3-nitroaniline, 2-methoxy-5-nitroaniline, 2,4-dinitrophenol, and methoxy-dinitrophenol, which are in good agreement with computational modeling results of bond strengths. The main DNAN photodegradation pathways are therefore proposed. Predicted eco-toxicity values suggested that the parent compound DNAN, methoxy-nitrophenols, methoxy-nitroanilines and the other two products (2,4-dinitrophenol and methoxy-dinitrophenol) would be harmful to fish and daphnid. Our study provides improved insight about the rain dissolution and photochemical behavior of IM formulations under natural conditions, which helps to form target-oriented strategies to mitigate explosive contamination in military training sites.
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Affiliation(s)
- Chao Qin
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China; Biosphere 2, University of Arizona, Oracle, AZ, 85721-0158, United States.
| | - Leif Abrell
- Department of Environmental Science, University of Arizona, Tucson, AZ, 85721-0038, United States
| | - Diego Troya
- Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Edward Hunt
- Biosphere 2, University of Arizona, Oracle, AZ, 85721-0158, United States
| | - Susan Taylor
- U.S. Army Engineer Research and Development Center, Hanover, NH, 03755-1290, United States
| | - Katerina Dontsova
- Biosphere 2, University of Arizona, Oracle, AZ, 85721-0158, United States; Department of Environmental Science, University of Arizona, Tucson, AZ, 85721-0038, United States.
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8
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A review of treatment methods for insensitive high explosive contaminated wastewater. Heliyon 2021; 7:e07438. [PMID: 34401549 PMCID: PMC8353291 DOI: 10.1016/j.heliyon.2021.e07438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/01/2021] [Accepted: 06/25/2021] [Indexed: 11/28/2022] Open
Abstract
Insensitive high explosive materials (IHE) such as 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN) are increasingly being used in formulations of insensitive munitions alongside 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). Load, assembly and packing (LAP) facilities that process munitions produce wastewater contaminated with IHE which must be treated before discharge. Some facilities can produce as much as 90,000 L of contaminated wastewater per day. In this review, methods of wastewater treatment are assessed in terms of their strengths, weaknesses, opportunities and threats for their use in production of IHE munitions including their limitations and how they could be applied to industrial scale LAP facilities. Adsorption is identified as a suitable treatment method, however the high solubility of NTO, up to 16.6 g.L−1 which is 180 times higher that of TNT, has the potential to exceed the adsorptive capacity of carbon adsorption systems. The key properties of the adsorptive materials along the selection of adsorption models are highlighted and recommendations on how the limitations of carbon adsorption systems for IHE wastewater can be overcome are offered, including the modification of carbons to increase adsorptive capacity or reduce costs.
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Wang C, Fuller ME, Heraty LJ, Hatzinger PB, Sturchio NC. Photocatalytic mechanisms of 2,4-dinitroanisole degradation in water deciphered by C and N dual-element isotope fractionation. JOURNAL OF HAZARDOUS MATERIALS 2021; 411:125109. [PMID: 33858090 DOI: 10.1016/j.jhazmat.2021.125109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/16/2020] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
In surface water environments, photodegradation may be an important process for the natural attenuation of 2,4-dinitroanisole (DNAN). Understanding the photolysis and photocatalysis mechanisms of DNAN is difficult because the photosensitivity of nitro groups and the behavior of DNAN as a potential photosensitizer are unclear in aqueous solutions. Here, we investigate the degradation mechanisms of DNAN under UV-A (λ ~ 350 nm) and UV-C (λ ~ 254 nm) irradiation in a photolysis reactor where aqueous solution was continuously recycled through a UV-irradiated volume from a non-irradiated external reservoir. By tracking C and N isotopic fractionation in DNAN and its reaction products, we observed normal 13C fractionation (εC = -3.34‰) and inverse 15N fractionation (εN = +12.30‰) under UV-A (λ ~ 350 nm) irradiation, in contrast to inverse 13C fractionation (εC = +1.45‰) and normal 15N fractionation (εN = -3.79‰) under UV-C (λ ~ 254 nm) irradiation. These results indicate that DNAN can act as a photosensitizer and may follow a product-to-parent reversion mechanism in surface water environments. The data also indicate that photocatalytic degradation of DNAN in aqueous systems can be monitored via C and N stable isotope analysis.
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Affiliation(s)
- Chunlei Wang
- Department of Earth Sciences, University of Delaware, Newark, DE 19716, USA.
| | - Mark E Fuller
- Aptim Federal Services, LLC, Lawrenceville, NJ 08648, USA
| | - Linnea J Heraty
- Department of Earth Sciences, University of Delaware, Newark, DE 19716, USA
| | | | - Neil C Sturchio
- Department of Earth Sciences, University of Delaware, Newark, DE 19716, USA
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10
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Lotufo GR, Boyd RE, Harmon AR, Bednar AJ, Smith JC, Simini M, Sunahara GI, Hawari J, Kuperman RG. Accumulation of Insensitive Munition Compounds in the Earthworm Eisenia andrei from Amended Soil: Methodological Considerations for Determination of Bioaccumulation Factors. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:1713-1725. [PMID: 33646621 DOI: 10.1002/etc.5028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/11/2021] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
The present study investigates the bioaccumulation of the insensitive munition compounds 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO), developed for future weapons systems to replace current munitions containing sensitive explosives. The earthworm Eisenia andrei was exposed to sublethal concentrations of DNAN or NTO amended in Sassafras sandy loam. Chemical analysis indicated that 2- and 4-amino-nitroanisole (2-ANAN and 4-ANAN, respectively) were formed in DNAN-amended soils. The SumDNAN (sum of DNAN, 2-ANAN, and 4-ANAN concentrations) in soil decreased by 40% during the 14-d exposure period. The SumDNAN in the earthworm body residue increased until day 3 and decreased thereafter. Between days 3 and 14, there was a 73% decrease in tissue uptake that was greater than the 23% decrease in the soil concentration, suggesting that the bioavailable fraction may have decreased over time. By day 14, the DNAN concentration accounted for only 45% of the SumDNAN soil concentration, indicating substantial DNAN transformation in the presence of earthworms. The highest bioaccumulation factor (BAF; the tissue-to-soil concentration ratio) was 6.2 ± 1.0 kg/kg (dry wt) on day 3 and decreased to 3.8 ± 0.8 kg/kg by day 14. Kinetic studies indicated a BAF of 2.3 kg/kg, based on the earthworm DNAN uptake rate of 2.0 ± 0.24 kg/kg/d, compared with the SumDNAN elimination rate of 0.87 d-1 (half-life = 0.79 d). The compound DNAN has a similar potential to bioaccumulate from soil compared with trinitrotoluene. The NTO concentration in amended soil decreased by 57% from the initial concentration (837 mg NTO/kg dry soil) during 14 d, likely due to the formation of unknown transformation products. The bioaccumulation of NTO was negligible (BAF ≤ 0.018 kg/kg dry wt). Environ Toxicol Chem 2021;40:1713-1725. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- G R Lotufo
- Environmental Laboratory, Engineer Research and Development Center, US Army, Vicksburg, Mississippi, USA
| | - R E Boyd
- Environmental Laboratory, Engineer Research and Development Center, US Army, Vicksburg, Mississippi, USA
| | - A R Harmon
- Environmental Laboratory, Engineer Research and Development Center, US Army, Vicksburg, Mississippi, USA
| | - A J Bednar
- Environmental Laboratory, Engineer Research and Development Center, US Army, Vicksburg, Mississippi, USA
| | - J C Smith
- Environmental Laboratory, Engineer Research and Development Center, US Army, Vicksburg, Mississippi, USA
| | - M Simini
- US Army Chemical Biological Center, Aberdeen Proving Ground, Maryland, USA
| | - G I Sunahara
- Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, QC, Canada
| | - J Hawari
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - R G Kuperman
- US Army Chemical Biological Center, Aberdeen Proving Ground, Maryland, USA
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11
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Sviatenko LK, Gorb L, Leszczynska D, Okovytyy SI, Shukla MK, Leszczynski J. Catalytic role of solvated electron in the spontaneous degradation of insensitive munition compounds: computational chemistry investigation. Struct Chem 2021. [DOI: 10.1007/s11224-020-01710-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Menezes O, Melo N, Paraiso M, Freitas D, Florêncio L, Kato MT, Gavazza S. The key role of oxygen in the bioremoval of 2,4-diaminoanisole (DAAN), the biotransformation product of the insensitive munitions compound 2,4-dinitroanisole (DNAN), over other electron acceptors. CHEMOSPHERE 2021; 267:128862. [PMID: 33183786 DOI: 10.1016/j.chemosphere.2020.128862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/19/2020] [Accepted: 11/02/2020] [Indexed: 06/11/2023]
Abstract
Insensitive munitions compounds, such as 2,4-dinitroanisole (DNAN), are replacing conventional explosives. DNAN is anaerobically reduced to 2,4-diaminoanisole (DAAN), a toxic aromatic amine. However, the removal of DAAN under different redox conditions is yet to be elucidated. Herein, we analyzed DAAN consumption in biotic and abiotic microcosms when exposed to different redox conditions (without added electron acceptor, without added electron acceptor but with pyruvate as a co-substrate, with sulfate, with nitrate, and with oxygen), using an anaerobic sludge as inoculum. We observed that DAAN autoxidation, an abiotic reaction, was significant in microaerobic environments. DAAN also reacted abiotically with heat-killed sludge up to a saturation limit of 67.4 μmol DAAN (g VSS heat-killed sludge)-1. Oxygen caused the fastest removal of DAAN in live sludge among the conditions tested. Treatments without added electron acceptors (with or without pyruvate) presented similar DAAN removal performances, although slower than the treatment with oxygen. Sulfate did not exhibit any effect on DAAN removal compared to the treatment without added electron acceptors. Nitrate, however, inhibited the process. An enrichment culture from the microcosms exposed to oxygen could be developed using DAAN as the sole substrate in microaerobic conditions. The enrichment profoundly changed the microbial community. Unclassified microorganisms accounted for 85% of the relative abundance in the enrichment culture, suggesting that DAAN microaerobic removal might have involved organisms that were not yet described. Our results suggest that DAAN microaerobic treatment can be coupled to DNAN anaerobic reduction in sludge, improving the treatment of DNAN-containing wastewaters.
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Affiliation(s)
- Osmar Menezes
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil.
| | - Natanna Melo
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil
| | - Matheus Paraiso
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil
| | - Danúbia Freitas
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil
| | - Lourdinha Florêncio
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil
| | - Mario T Kato
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil
| | - Savia Gavazza
- Laboratório de Saneamento Ambiental, Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-530, Brazil.
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Kadoya WM, Sierra-Alvarez R, Jagadish B, Wong S, Abrell L, Mash EA, Field JA. Covalent bonding of aromatic amine daughter products of 2,4-dinitroanisole (DNAN) with model quinone compounds representing humus via nucleophilic addition. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115862. [PMID: 33120159 DOI: 10.1016/j.envpol.2020.115862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/30/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
2,4-Dinitroanisole (DNAN) is a component of insensitive munitions (IM), which are replacing traditional explosives due to their improved safety. Incomplete IM combustion releases DNAN onto the soil, where it can leach into the subsurface with rainwater, encounter anoxic conditions, and undergo (a)biotic reduction to aromatic amines 2-methoxy-5-nitroaniline (MENA), 4-methoxy-3-nitroaniline (iMENA, isomer of MENA), and 2,4-diaminoanisole (DAAN). We report here studies of nucleophilic addition mechanisms that may account for the sequestration of aromatic amine daughter products of DNAN into soil organic matter (humus), effectively removing these toxic compounds from the aqueous environment. Because quinones are important moieties in humus, we incubated MENA, iMENA, DAAN, and related analogs with model compounds 1,4-benzoquinone and 2,3-dimethyl-1,4-benzoquinone under anoxic conditions. Mass spectrometry and ultra-high performance liquid chromatography revealed that the aromatic amines had covalently bonded to either carbonyl carbons or ring carbons β to carbonyl carbons of the quinones, producing a mixture of imines and Michael adducts, respectively. These products formed rapidly and accumulated in the one-to four-day incubations. Nucleophilic addition reactions, which do not require catalysis or oxic conditions, are proposed as a mechanism resulting in the binding of DNAN to soil observed in previous studies. To remediate sites contaminated with DNAN or other nitroaromatics, reducing conditions and humus amendments may promote their immobilization into the soil matrix.
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Affiliation(s)
- Warren M Kadoya
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ, 85721, USA
| | - Reyes Sierra-Alvarez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ, 85721, USA
| | - Bhumasamudram Jagadish
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721, USA
| | - Stanley Wong
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ, 85721, USA
| | - Leif Abrell
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721, USA; Department of Environmental Science, The University of Arizona, Tucson, AZ, 85721, USA
| | - Eugene A Mash
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ, 85721, USA
| | - Jim A Field
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ, 85721, USA.
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14
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Wang C, Wallace AF, Heraty L, Qi H, Sturchio NC. Alkaline hydrolysis pathway of 2,4-dinitroanisole verified by 18O tracer experiment. JOURNAL OF HAZARDOUS MATERIALS 2020; 396:122627. [PMID: 32305747 DOI: 10.1016/j.jhazmat.2020.122627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/30/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
The environmental fate of insensitive munitions compounds, such as 2,4-dinitroanisole (DNAN), has drawn increasing attention because of their growing use in military activities. One of the main attenuation mechanisms of DNAN degradation in aqueous environments is alkaline hydrolysis. We investigated the pathway for alkaline hydrolysis of DNAN at pH 12 by a combined approach of experiment and theory. An experiment using 18O-labeled water was performed to verify the reaction pathway. Calculated free energies for two putative reaction pathways by density-functional theory optimized at the SMD(Pauling)/M06-2X/6-311++G(2d,2p) level including explicit solvation of DNAN by 10 H2O molecules and one OH- ion gave a prediction in agreement with the experimental result. The verified reaction pathway for alkaline hydrolysis of DNAN is a SN2Ar nucleophilic aromatic substitution with a methoxy leaving group (OCH3) at the C1 site.
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Affiliation(s)
- Chunlei Wang
- Department of Earth Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Adam F Wallace
- Department of Earth Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Linnea Heraty
- Department of Earth Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Haiping Qi
- Reston Stable Isotope Laboratory, U.S. Geological Survey, Reston, VA, 20192, USA
| | - Neil C Sturchio
- Department of Earth Sciences, University of Delaware, Newark, DE, 19716, USA.
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Moores LC, Kennedy AJ, May L, Jordan SM, Bednar AJ, Jones SJ, Henderson DL, Gurtowski L, Gust KA. Identifying degradation products responsible for increased toxicity of UV-Degraded insensitive munitions. CHEMOSPHERE 2020; 240:124958. [PMID: 31726587 DOI: 10.1016/j.chemosphere.2019.124958] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/21/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
Degradation of insensitive munitions (IMs) by ultraviolet (UV) light has become a topic of concern following observations that some UV-degradation products have increased toxicity relative to parent compounds in aquatic organisms. The present investigation focused on the Army's IM formulation, IMX-101, which is composed of three IM constituents: 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine (NQ). The IM constituents and IMX-101 were irradiated in a UV photo-reactor and then administered to Daphnia pulex in acute (48 h) exposures comparing toxicities relative to the parent materials. UV-degradation of DNAN had little effect on mortality whereas mortality for UV-degraded NTO and NQ (and associated degradation products) increased by factors of 40.3 and 1240, respectively, making UV-degraded NQ the principle driver of toxicity when IMX-101 is UV-degraded. Toxicity investigations for specific products formed during UV-degradation of NQ, confirmed greater toxicity than the parent NQ for degradation products including guanidine, nitrite, ammonia, nitrosoguanidine, and cyanide. Summation of the individual toxic units for the complete set of individually measured UV-degradation products identified for NQ only accounted for 25% of the overall toxicity measured in the exposures to the UV-degraded NQ product mixture. From these toxic unit calculations, nitrite followed by CN- were the principal degradation products contributing to toxicity. Given the underestimation of toxicity using the sum toxic units for the individually measured UV-degradation products of NQ, we conclude that: (1) other unidentified NQ degradation products contributed principally to toxicity and/or (2) synergistic toxicological interactions occurred among the NQ degradation product mixture that exacerbated toxicity.
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Affiliation(s)
- Lee C Moores
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
| | - Alan J Kennedy
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Lauren May
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Shinita M Jordan
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Anthony J Bednar
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Stacy J Jones
- HX5, 212 Eglin Parkway SE, Ft, Walton Beach, FL, 32548, USA
| | - David L Henderson
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Luke Gurtowski
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
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Becher JB, Beal SA, Taylor S, Dontsova K, Wilcox DE. Photo-transformation of aqueous nitroguanidine and 3-nitro-1,2,4-triazol-5-one: Emerging munitions compounds. CHEMOSPHERE 2019; 228:418-426. [PMID: 31051343 DOI: 10.1016/j.chemosphere.2019.04.131] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
Two major components of insensitive munition formulations, nitroguanidine (NQ) and 3-nitro-1,2,4-triazol-5-one (NTO), are highly water soluble and therefore likely to photo-transform while in solution in the environment. The ecotoxicities of NQ and NTO solutions are known to increase with UV exposure, but a detailed accounting of aqueous degradation rates, products, and pathways under different exposure wavelengths is currently lacking. Here, we irradiated aqueous solutions of NQ and NTO over a 32-h period at three ultraviolet wavelengths (254 nm, 300 nm, and 350 nm) and analyzed their degradation rates and transformation products. NQ was completely degraded by 30 min at 254 nm and by 4 h at 300 nm, but it was only 10% degraded after 32 h at 350 nm. Mass recoveries of NQ and its transformation products were ≥80% for all three wavelengths, and consisted of large amounts of guanidine, nitrate, and nitrite, and smaller amounts of cyanamide, cyanoguanidine, urea, and ammonium. NTO degradation was greatest at 300 nm with 3% remaining after 32 h, followed by 254 nm (7% remaining) and 350 nm (20% remaining). Mass recoveries of NTO and its transformation products were high for the first 8 h but decreased to 22-48% by 32 h, with the major aqueous products identified as ammonium, nitrate, nitrite, and a urazole intermediate. Environmental half-lives of NQ and NTO in pure water were estimated as 4 and 6 days, respectively. We propose photo-degradation pathways for NQ and NTO supported by observed and quantified degradation products and changes in solution pH.
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Affiliation(s)
- Julie B Becher
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA
| | - Samuel A Beal
- U.S Army Cold Regions Research and Engineering Laboratory, Hanover, NH 03755, USA.
| | - Susan Taylor
- U.S Army Cold Regions Research and Engineering Laboratory, Hanover, NH 03755, USA
| | - Katerina Dontsova
- Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ 85721-0158, USA
| | - Dean E Wilcox
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, USA
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Hadnagy E, Mai A, Smolinski B, Braida W, Koutsospyros A. Characterization of Mg-based bimetal treatment of insensitive munition 2,4-dinitroanisole. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:24403-24416. [PMID: 29909531 DOI: 10.1007/s11356-018-2493-1] [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: 02/22/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
The manufacturing of insensitive munition 2,4-dinitroanisole (DNAN) generates waste streams that require treatment. DNAN has been treated previously with zero-valent iron (ZVI) and Fe-based bimetals. Use of Mg-based bimetals offers certain advantages including potential higher reactivity and relative insensitivity to pH conditions. This work reports preliminary findings of DNAN degradation by three Mg-based bimetals: Mg/Cu, Mg/Ni, and Mg/Zn. Treatment of DNAN by all three bimetals is highly effective in aqueous solutions (> 89% removal) and wastewater (> 91% removal) in comparison with treatment solely with zero-valent magnesium (ZVMg; 35% removal). Investigation of reaction byproducts supports a partial degradation pathway involving reduction of the ortho or para nitro to amino group, leading to 2-amino-4-nitroanisole (2-ANAN) and 4-amino-2-nitroanisole (4-ANAN). Further reduction of the second nitro group leads to 2,4-diaminoanisole (DAAN). These byproducts are detected in small quantities in the aqueous phase. Carbon mass balance analysis suggests near-complete closure (91%) with 12.4 and 78.4% of the total organic carbon (TOC) distributed in the aqueous and mineral bimetal phases, respectively. Post-treatment surface mineral phase analysis indicates Mg(OH)2 as the main oxidized species; oxide formation does not appear to impair treatment.
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Affiliation(s)
- Emese Hadnagy
- Department of Civil and Environmental Engineering, University of New Haven, West Haven, CT, USA.
| | - Andrew Mai
- Department of Civil, Environmental, and Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, USA
| | | | - Washington Braida
- Department of Civil, Environmental, and Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, USA
| | - Agamemnon Koutsospyros
- Department of Civil and Environmental Engineering, University of New Haven, West Haven, CT, USA
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18
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UV-activated persulfate oxidation of the insensitive munitions compound 2,4-dinitroanisole in water: Kinetics, products, and influence of natural photoinducers. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2018.04.044] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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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: 22] [Impact Index Per Article: 3.7] [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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Halasz A, Hawari J, Perreault NN. New Insights into the Photochemical Degradation of the Insensitive Munition Formulation IMX-101 in Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:589-596. [PMID: 29244492 DOI: 10.1021/acs.est.7b04878] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This study describes photolysis of the insensitive munition formulation IMX-101 [2,4-dinitroanisole (DNAN), NQ (nitroguanidine), and 3-nitro-1,2,4-triazol-5-one (NTO)] in aqueous solutions using a solar simulating photoreactor. Due to a large variance in the water solubility of the three constituents DNAN (276 mg L-1), NQ (5,000 mg L-1), and NTO (16,642 mg L-1), two solutions of IMX-101 were prepared: one with low concentration (109.3 mg L-1) and another with high concentration (2831 mg L-1). The degradation rate constants of DNAN, NQ, and NTO (0.137, 0.075, and 0.202 d-1, respectively) in the low concentration solution were lower than those of the individually photolyzed components (0.262, 1.181, and 0.349 d-1, respectively). In the high concentration solution, the molar loss of NTO was 4.3 times higher than that of NQ after 7 days of irradiation, although NQ was two times more concentrated and that NQ alone degraded faster than NTO. In addition to the known degradation products, DNAN removal in IMX-101 was accompanied by multiple productions of methoxydinitrophenols, which were not observed during photolysis of DNAN alone. One route for the formation of methoxydinitrophenols was suggested to involve photonitration of the DNAN photoproduct methoxynitrophenol during simultaneous photodenitration of NQ and NTO in IMX-101. Indeed, when DNAN was photolyzed in the presence of 15NO2-labeled explosive CL-20, we detected methoxydinitrophenols with an increase of 1 mass unit, indicating that denitration of DNAN and renitration of products simultaneously occurred. As was the case with DNAN, we found that guanidine, a primary degradation product of NQ, also underwent renitration in the presence of NTO and the photocatalyst TiO2. We concluded that the three constituents of IMX-101 can be photodegraded in surface water and that fate and primary degradation products of IMX-101 can be influenced by the interactions between the formulation ingredients and their degradation products.
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Affiliation(s)
- Annamaria Halasz
- National Research Council Canada , 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
| | - Jalal Hawari
- National Research Council Canada , 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
| | - Nancy N Perreault
- National Research Council Canada , 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
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Taylor S, Dontsova K, Walsh M. Insensitive Munitions Formulations: Their Dissolution and Fate in Soils. CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2017. [DOI: 10.1007/978-3-319-59208-4_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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