Biodegradation and mineralization of isotopically labeled TNT and RDX in anaerobic marine sediments

Ariyarathna, Thivanka; Vlahos, Penny; Smith, Richard; Fallis, Stephen; Groshens, Thomas J.; Tobias, Craig R.

doi:10.1002/etc.3666

Cited by 15 publications

(6 citation statements)

References 36 publications

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“…Elevated TOC level generated lower redox potential in sediment via TOC mineralization by natural microbial assemblages and also promoted microbially mediated anaerobic degradation of both DNAN and NTO via reduction and deamination (Krzmarzick et al, 2015;Mark et al, 2016;Temple et al, 2018). Removal under the iron-and sulfate-reducing conditions has been previously reported for legacy munitions, including TNT and RDX (Ariyarathna et al, 2017;Cho et al, 2012;Moser & Nealson, 1996). In the present study we observed similar links for DNAN and NTO removal in biotic incubations.…”

Section: Biotic Removal Of Dnan and Nto In Freshwater Sediment Incuba...supporting

confidence: 87%

“…Sediments provide zones for more favorable removal of munitions constituents than overlying water (Ariyarathna et al, 2017; Smith et al, 2013). Flask‐scale studies show that the nitro groups of DNAN and NTO can be reduced in sediments, forming amino products that serve as principal degradation products of these IHE constituents (Fida et al, 2014; Krzmarzick et al, 2015; Olivares et al, 2016; Perreault et al, 2012; Schroer et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Adsorption and Removal Kinetics of 2,4‐Dinitroanisole and Nitrotriazolone in Contrasting Freshwater Sediments: Batch Study

Ariyarathna

Twarz

Tobias

2022

Enviro Toxic and Chemistry

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Environmental release of 2,4‐dinitroanisole (DNAN) and 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) is of great concern due to high migration potential in the environment. In the present study we evaluated the adsorption and microbially‐mediated removal kinetics of dissolved DNAN and NTO in contrasting freshwater sediments with different total organic carbon (TOC) content. River sand (low TOC), pond silt (high TOC), clay‐rich lake sediment (low TOC), wetland silt (high TOC), carbonate sand (low TOC), and iron‐rich clay (low TOC) were evaluated. Separate abiotic and biotic bench‐top sediment slurry incubations were carried out at 23, 15, and 4 °C for DNAN and NTO. Experiments were conducted over 3 weeks. Time series aqueous samples and sediment samples collected at the end of the experiment were analyzed for DNAN and NTO concentrations. The DNAN compound equilibrated with sediment within the first 2 h after addition whereas NTO showed no adsorption. 2,4‐Dinitroanisole adsorbed more onto fine‐grained organic‐rich sediments (Kd = 2–40 L kg−1 sed−1) than coarse‐grained organic‐poor sediments (Kd = 0.2–0.6 L kg−1 sed−1), and the TOC content and cation exchange capacity of sediment were reliable predictors for abiotic DNAN adsorption. Adsorption rate constants and equilibrium partitioning constants for DNAN were inversely proportional to temperature in all sediment types. The biotic removal half‐life of DNAN was faster (t1/2 = 0.1–58 h) than that of NTO (t1/2 = 5–347 h) in all sediment slurries. Biotic removal rates (t1/2 = 0.1–58 h) were higher than abiotic rates (t1/2 = 0.3–107 h) for DNAN at 23 °C. Smaller grain size coupled with higher TOC content enhanced biotic NTO and DNAN removal in freshwater environments. Environ Toxicol Chem 2023;42:46–59. © 2022 SETAC

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Section: Biotic Removal Of Dnan and Nto In Freshwater Sediment Incuba...supporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Adsorption and Removal Kinetics of 2,4‐Dinitroanisole and Nitrotriazolone in Contrasting Freshwater Sediments: Batch Study

Ariyarathna

Twarz

Tobias

2022

Enviro Toxic and Chemistry

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“…Using marine mesocosms, Tobias, Vlahos, and co-workers performed a series of experiments tracking the fate of 15 N-TNT and 15 N-RDX into the various nitrogen pools, macro and microbiota. − Although it is difficult to directly compare among different systems and different mineralization methods, with roughly 400 μg of RDX L –1 added at day 1 and 6% mineralized by day 21, the mineralization rate estimate of ca. 1 μg of RDX L –1 day –1 to N 2 is comparable to the Rmin rates to CO 2 in coastal waters measured in this study.…”

Section: Discussionmentioning

confidence: 99%

Ecosystem Capacity for Microbial Biodegradation of Munitions Compounds and Phenanthrene in Three Coastal Waterways in North Carolina, United States

Montgomery

Boyd

Hall³

et al. 2020

ACS Omega

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Munitions compounds (i.e., 2,4,6-trinitrotoluene (TNT), octahy-dro-1,3,5,7-tetranitro-1,3,5,7-tetrazocin (HMX), and hexadydro-1,3,5-trinitro-1,3,5-triazin (RDX), also called energetics) were originally believed to be recalcitrant to microbial biodegradation based on historical groundwater chemical attenuation data and laboratory culture work. More recently, it has been established that natural bacterial assemblages in coastal waters and sediment can rapidly metabolize these organic nitrogen sources and even incorporate their carbon and nitrogen into bacterial biomass. Here, we report on the capacity of natural microbial assemblages in three coastal North Carolina (United States) estuaries to metabolize energetics and phenanthrene (PHE), a proxy for terrestrial aromatic compounds. Microbial assemblages generally had the highest ecosystem capacity (mass of the compound mineralized per average estuarine residence time) for HMX (21–5463 kg) > RDX (1.4–5821 kg) ≫ PHE (0.29–660 kg) > TNT (0.25–451 kg). Increasing antecedent precipitation tended to decrease the ecosystem capacity to mineralize TNT in the Newport River Estuary, and PHE and TNT mineralization were often highest with increasing salinity. There was some evidence from the New River Estuary that increased N-demand (due to a phytoplankton bloom) is associated with increased energetic mineralization rates. Using this type of analysis to determine the ecosystem capacity to metabolize energetics can explain why these compounds are rarely detected in seawater and marine sediment, despite the known presence of unexploded ordnance or recent use in military training exercises. Overall, measuring the ecosystem capacity may help predict the effects of climate change (warming and altered precipitation patterns) and other perturbations on exotic compound fate and transport within ecosystems and provide critical information for managers and decision-makers to develop management strategies based on these changes.

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“…In the control microcosm, bottles were autoclaved again after addition of inocula, and finally RDX was added in the autoclaved bottles. Microcosm bottles were completely wrapped with aluminum foil to avoid photo-degradation of RDX [ 36 ]. The final pH was 7.1 ± 0.2.…”

Section: Methodsmentioning

confidence: 99%

A Sporolactobacillus-, Clostridium-, and Paenibacillus- Dominant Microbial Consortium Improved Anaerobic RDX Detoxification by Starch Addition

Khan¹,

Yoo²,

Kim³

et al. 2020

J. Microbiol. Biotechnol.

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In the present study, an anaerobic microbial consortium for the degradation of hexahydro-1,3,5trinitro-1,3,5-triazine (RDX) was selectively enriched with the co-addition of RDX and starch under nitrogen-deficient conditions. Microbial growth and anaerobic RDX biodegradation were effectively enhanced by the co-addition of RDX and starch, which resulted in increased RDX biotransformation to nitroso derivatives at a greater specific degradation rate than those for previously reported anaerobic RDX-degrading bacteria (isolates). The accumulation of the most toxic RDX degradation intermediate (MNX [hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine]) was significantly reduced by starch addition, suggesting improved RDX detoxification by the co-addition of RDX and starch. The subsequent MiSeq sequencing that targeted the bacterial 16S rRNA gene revealed that the Sporolactobacillus, Clostridium, and Paenibacillus populations were involved in the enhanced anaerobic RDX degradation. These results suggest that these three bacterial populations are important for anaerobic RDX degradation and detoxification. The findings from this work imply that the Sporolactobacillus, Clostridium, and Paenibacillus dominant microbial consortium may be valuable for the development of bioremediation resources for RDX-contaminated environments.

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Biodegradation and mineralization of isotopically labeled TNT and RDX in anaerobic marine sediments

Cited by 15 publications

References 36 publications

Adsorption and Removal Kinetics of 2,4‐Dinitroanisole and Nitrotriazolone in Contrasting Freshwater Sediments: Batch Study

Adsorption and Removal Kinetics of 2,4‐Dinitroanisole and Nitrotriazolone in Contrasting Freshwater Sediments: Batch Study

Ecosystem Capacity for Microbial Biodegradation of Munitions Compounds and Phenanthrene in Three Coastal Waterways in North Carolina, United States

A Sporolactobacillus-, Clostridium-, and Paenibacillus- Dominant Microbial Consortium Improved Anaerobic RDX Detoxification by Starch Addition

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