Microbial remediation of NTO in aqueous industrial wastes

Campion, Laurence Le; Vandais, A.; Ouazzani, Jamal

doi:10.1111/j.1574-6968.1999.tb13662.x

Cited by 57 publications

(70 citation statements)

References 20 publications

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“…Biotic (Le Campion et al, 1998a; Le Campion et al, 1999a; Krzmarzick et al, 2015; Richard and Weidhass, 2014) and abiotic (Le Campion et al, 1999b; Linker et al, 2015) degradation of NTO has been evaluated in a few recent studies. A bacterial strain, Bacillus licheniformis was used to degrade NTO in industrial wastewater (Le Campion et al, 1999a).…”

Section: Introductionmentioning

confidence: 99%

Sequential anaerobic-aerobic biodegradation of emerging insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO)

et al. 2017

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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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Section: Introductionmentioning

confidence: 99%

Sequential anaerobic-aerobic biodegradation of emerging insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO)

et al. 2017

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“…NTO is highly soluble (16,642.0 mg L À1 at 25 C) (Spear et al, 1989) and its transport to groundwater used as potable water source could result in human exposure to the chemical. While NTO showed low toxicity to the freshwater organism Ceriodaphnia dubia, green algae Selenastrum capricornutum (Haley et al, 2009), and Rana pipiens tadpoles (Stanley et al, 2015), it is a male reproductive toxicant in rats (Wallace, 2011;Lent et al, 2015) and was reported to form transformation products that can be toxic if they behave similarly to metabolic intermediates of other nitro-compounds (Le Campion et al, 1999b). Based on these risks, accurate soil adsorption coefficients (K d s) and transformation rate constants are necessary to simulate and predict NTO fate and transport to groundwater.…”

Section: Introductionmentioning

confidence: 99%

“…Microbial transformation studies have shown that NTO can undergo nitroreduction under anaerobic conditions (Krzmarzick et al, 2015) and form 5-amino-1,2,4-triazol-3-one (ATO). ATO can further transform under aerobic conditions to CO 2 , urea, and inorganic nitrogen species (Le Campion et al, 1999b;Krzmarzick et al, 2015). Mark et al (2016) conducted a series of kinetic and equilibrium batch experiments to determine first order transformation rate constants (k), K d s and Freundlich adsorption coefficients (K f s) for NTO using multiple soils with a range of properties.…”

Section: Introductionmentioning

confidence: 99%

Column transport studies of 3-nitro-1,2,4-triazol-5-one (NTO) in soils

et al. 2017

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h i g h l i g h t sThis is the first study to examine transport behavior of dissolved NTO, a new IM compound. We measured adsorption, retardation and transformation of dissolved NTO in 8 soils. NTO absorption and retardation were low (K d < 1 cm 3 g À1 ).Transformation rates increased with time for high OC soils. Organic carbon and microbial activity promoted NTO transformation. a r t i c l e i n f o a b s t r a c tDevelopment of the new, insensitive, energetic compound, NTO (3-nitro-1,2,4-triazol-5-one), creates need for the data on NTO's fate and transport to predict its behavior in the environment and potential for groundwater contamination. To measure the transport of NTO in soils, we conducted miscibledisplacement experiments under steady state and interrupted flow conditions using eight soils having varying physical and geochemical properties. The breakthrough curve (BTC) data were analyzed using temporal moment analysis and simulated using HYDRUS-1D to determine transport parameters and better understand the mechanisms of sorption and transformation. Parameters determined from the miscible-displacement study were compared to results obtained from batch experiments conducted for the same soils, and examined in relation to soil properties. Column NTO linear adsorption coefficients (K d ) were low and correlated well (P ¼ 0.000049) with measurements from the batch studies. NTO transformation rate constants increased and NTO recovery decreased with increase in soil organic carbon (OC) content. Autoclaved soils had slower transformation rates and greater NTO recoveries indicating that microorganisms play a role in NTO transformation. In addition, the transformation rate increased with time in soils with higher OC. Monod-type kinetics was implemented in HYDRUS-1D to simulate the observed increase in transformation rate with time. We think this phenomenon is due to bacterial growth. Results indicate very low adsorption of NTO in a range of soils, but natural attenuation through transformation that, depending on soil OC content and hydraulic residence time, could result in complete removal of NTO.

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“…Its nitro group is reduced to an amino group, yielding 3-amino-1,2,4-triazol-5-one (ATO, Figure 1), which was found to be persistent in the soil in the absence of oxygen [5–7]. The reductive transformation of NTO to ATO could alter the molecule’s toxicity.…”

Section: Introductionmentioning

confidence: 99%

Ecotoxicity of the insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO) and its reduced metabolite 3-amino-1,2,4-triazol-5-one (ATO)

Madeira

Field

Simonich

et al. 2018

Journal of Hazardous Materials

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The insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO) was recently approved by the U.S. Army to replace cyclotrimethylene trinitramine (RDX) in conventional explosives. As its use becomes widespread, concern about the potential toxicity of NTO increases. NTO can undergo microbial reduction to 3-amino-1,2,4-triazol-5-one (ATO), which is recalcitrant in waterlogged soils. In this study, the acute toxicity of NTO and ATO towards various organisms, including microorganisms (i.e., methanogenic archaea, aerobic heterotrophs, and Aliivibrio fischeri (Microtox assay)), the microcrustacean Daphnia magna (ATO only), and zebrafish embryos (Danio rerio), was assessed. NTO was notably more inhibitory to methanogens than ATO (IC50=1.2 mM, >62.8 mM, respectively). NTO and ATO did not cause noteworthy inhibition on aerobic heterotrophs even at the highest concentrations tested (32.0 mM). High concentrations of both NTO and ATO were required to inhibit A. fischeri (IC20 = 19.2, 22.4 mM, respectively). D. magna was sensitive to ATO (LC50= 0.27 mM). Exposure of zebrafish embryos to NTO or ATO (750 µM) did not cause lethal or developmental effects (22 endpoints tested). However, both compounds led to swimming behavior abnormalities at low concentrations (7.5 µM). The results indicate that the reductive biotransformation of NTO could enhance or lower its toxicity according to the target organism.

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Microbial remediation of NTO in aqueous industrial wastes

Cited by 57 publications

References 20 publications

Sequential anaerobic-aerobic biodegradation of emerging insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO)

Sequential anaerobic-aerobic biodegradation of emerging insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO)

Column transport studies of 3-nitro-1,2,4-triazol-5-one (NTO) in soils

Ecotoxicity of the insensitive munitions compound 3-nitro-1,2,4-triazol-5-one (NTO) and its reduced metabolite 3-amino-1,2,4-triazol-5-one (ATO)

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