Stable Isotopes of Nitrate Reflect Natural Attenuation of Propellant Residues on Military Training Ranges

Bordeleau, Geneviève; Savard, Martine M.; Martel, Richard; Smirnoff, Anna; Ampleman, Guy; Thiboutot, Sonia

doi:10.1021/es4004526

Cited by 4 publications

(6 citation statements)

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“…Previous reports have suggested that explosives, including RDX, may be a source of NO 3 Ϫ contamination in groundwater and that the isotopic characteristics of explosivesderived NO 3 Ϫ may be distinguishable from other typical sources (23)(24)(25) product of anaerobic RDX degradation (Ϫ42 to Ϫ24‰) (e.g., in soils with heterogeneous redox conditions) could be substantially lower than those of most common NO 3 Ϫ sources. Conclusions.…”

Section: Discussionmentioning

confidence: 97%

“…Some reports have suggested that the degradation of explosives and propellants could be a source of NO 2 Ϫ or NO 3 Ϫ contamination in groundwater, with isotopic characteristics that may be distinguishable from other NO 3 Ϫ sources (23)(24)(25). Preliminary experiments indicate that NO 3 Ϫ produced during photochemical RDX degradation can have relatively low ␦ 15 N values compared to other major NO 3 Ϫ sources, whereas ␦ 18 O results appear to be more variable (23,24).…”

mentioning

confidence: 92%

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Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures

Fuller

Heraty

Condee

et al. 2016

Appl Environ Microbiol

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Kinetic isotopic fractionation of carbon and nitrogen during RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation was investigated with pure bacterial cultures under aerobic and anaerobic conditions. Relatively large bulk enrichments in 15 ؊ production were much larger than, but systematically related to, the bulk RDX N isotope effects with different bacteria. Apparent intrinsic 15 N-NO 2 ؊ values were consistent with an initial denitration pathway in the aerobic experiments and more complex processes of NO 2 ؊ formation associated with anaerobic ring cleavage. These results indicate the potential for isotopic analysis of residual RDX for the differentiation of degradation pathways and indicate that further efforts to examine the isotopic composition of potential RDX degradation products (e.g., NO x ) in the environment are warranted. IMPORTANCEThis work provides the first systematic evaluation of the isotopic fractionation of carbon and nitrogen in the organic explosive RDX during degradation by different pathways. It also provides data on the isotopic effects observed in the nitrite produced during RDX biodegradation. Both of these results could lead to better understanding of the fate of RDX in the environment and help improve monitoring and remediation technologies. Explosives manufacturing, testing, and training range activities have resulted in the release of explosive compounds, including the nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), in soils at numerous U.S. Department of Defense (DoD) installations. Because RDX is mobile in soils and persistent, it has also been detected in groundwater or drinking water at some of these sites (1, 2).There has been extensive research examining the biological degradation of explosive compounds by pure cultures of bacteria as well as mixed consortia (for a review, see reference 3). RDX biodegradation has been observed under a range of redox conditions (4-9), and at least three predominant degradation pathways have been elucidated (Fig. 1). Typically, RDX is degraded anaerobically as an electron acceptor, requiring a carbon source as an electron donor, and entails either successive reduction of the three nitro groups via successive two-electron (2e Ϫ ) transfers followed by ring cleavage (pathway A) or an earlier opening of the ring structure (pathway B1), with or without initial denitration (pathway B2). The specific mechanism of ring destabilization and the steps that lead to ring cleavage may be variable and remain subject to debate (6,7,10). A denitration reaction that converts hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) (in pathway A) through multiple intermediates to methylenedinitramine (MEDINA) (in pathway B) under anaerobic conditions has also been proposed (7,11,12). Aerobic degradation proceeds via two single-electron transfer steps resulting in sequential denitration (2 NO 2 Ϫ removed) followed by ring cleavage and production of 4-nitro-2,4-diazabutanal (NDAB) (pathway C) (7). Some bacteria are able to utilize R...

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Section: Discussionmentioning

confidence: 97%

mentioning

confidence: 92%

Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures

Fuller

Heraty

Condee

et al. 2016

Appl Environ Microbiol

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“…Burning of propellant in a booster rocket motor may leave some residue [30][31][32]. In order to get better comparative analysis of the chemical components of the CL-20/RDX-CMDB propellant surface before and after combustion, we firstly calculated the percentage of C, O, Al, Cu and Pb elements in the formulations, and the results were shown in Table 5.…”

Section: Combustion Residue Analysismentioning

confidence: 99%

Study on Comparative Performance of CL‐20/RDX‐based CMDB Propellants

Yang

Zheng

Zhang

2019

Propellants Explo Pyrotec

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The energy, combustion and combustion residues properties of composite modified double‐base (CMDB)propellants with CL‐20 were compared to those propellants with RDX. The energy characteristic of CL‐20/RDX‐CMDB propellants had also been calculated theoretically based on the principle of minimum free energy. The energy property of propellants with CL‐20 was found to be evidently enhanced in comparison to those propellants containing RDX. The findings on combustion properties revealed that the combustion properties of CL‐20‐CMDB propellants were contrary to the of RDX‐CMDB propellants. With the mass fraction of CL‐20 increasing in the propellants, the burning rates of propellants can be enhanced significantly, but the burning rates of propellants containing RDX decreased. Analysis of the combustion residues for CL‐20/RDX‐CMDB propellants revealed that the C, Cu and Pb elements aggregated on combustion surface, which may be useful for guiding the regulation of combustion performance of high‐performance CMDB propellants containing CL‐20.

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“…TNT can be degraded by direct absorption of light energy or by absorption of energy transferred from a photosensitised species such as hydroxyl radical, singlet oxygen or triplet-excited state dissolved organic matter (Kalderis et al 2011;Zeng and Arnold 2013). Isotopic analysis has also provided evidence for the natural attenuation of propellant residues exposed to sunlight (Bordeleau et al 2013). Results of the isotopic analysis indicated that propellant (nitroglycerin and nitrocellulose) combustion and degradation mediated by soil organic carbon produced nitrate (Fig.…”

Section: Photolysismentioning

confidence: 99%

Remediation of inorganic and organic contaminants in military ranges

Fayiga¹

2019

Environ. Chem.

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Environmental contextContaminants occur in the soil and water associated with military ranges. This review article describes how the extent of contamination depends not only on the type of military range and its period of activity, but also on the chemistry of both the soil and the contaminant. A full understanding of the soil chemistry is necessary to develop effective remediation methods for the restoration of these impacted environments. AbstractThis review discusses the contaminants associated with military ranges and the approaches taken to remediate these sites. The type and extent of contamination depends on the type of range, period of activity, soil chemistry and contaminant chemistry. Small arms firing ranges typically have high concentrations of metals and metalloids whereas military ranges typically have high concentrations of perchlorates, white phosphorus, explosives and propellants. For explosives, higher concentrations are found in sites that have undergone a low order detonation than in sites with a high order detonation. Remediation technologies for small arms firing ranges include leaching and immobilisation whereas for military ranges, methods such as alkaline hydrolysis, photolysis, bioremediation and phytoremediation have been tested. A lot of work has been done to immobilise metals/metalloids using soil amendments, which show a high effectiveness in stabilising them. Some of these amendments, however, also mobilise other co-contaminants. More studies are needed to simultaneously immobilise all inorganic contaminants. Explosives can be transformed into simpler non-toxic forms by photolysis, bioremediation or phytodegradation. The introduction of bacteria transgenes into plants has been used to enhance uptake and degradation of explosives in transgenic plants. Adoption of appropriate remediation technologies in impacted military ranges will reduce contaminant levels and protect public health.

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Stable Isotopes of Nitrate Reflect Natural Attenuation of Propellant Residues on Military Training Ranges

Cited by 4 publications

References 36 publications

Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures

Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures

Study on Comparative Performance of CL‐20/RDX‐based CMDB Propellants

Remediation of inorganic and organic contaminants in military ranges

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