Enhanced bioremediation of RDX and Co-Contaminants perchlorate and nitrate using an anaerobic dehalogenating consortium in a fractured rock aquifer

dc.contributor.authorLorah, Michelle M.
dc.contributor.authorVogler, Eric
dc.contributor.authorGebhardt, Fredrick E.
dc.contributor.authorGraves, Duane
dc.contributor.authorFedorowski Grabowski, Jennifer
dc.date.accessioned2022-03-04T19:32:23Z
dc.date.available2022-03-04T19:32:23Z
dc.date.issued2022-05
dc.description.abstractThe potential neurotoxic and carcinogenic effects of the explosives compound RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) on human health requires groundwater remediation strategies to meet low cleanup goals. Bioremediation of RDX is feasible through biostimulation of native microbes with an organic carbon donor but may be less efficient, or not occur at all, in the presence of the common co-contaminants perchlorate and nitrate. Laboratory tests compared biostimulation with bioaugmentation to achieve anaerobic degradation of RDX, perchlorate, and nitrate; a field pilot test was then conducted in a fractured rock aquifer with the selected bioaugmentation approach. Insignificant reduction of RDX, perchlorate, or nitrate was observed by the native microbes in microcosms, with or without biostimulation by addition of lactate. Tests of the RDX-degrading ability of the microbial consortium WBC-2, originally developed for dehalogenation of chlorinated volatile organic compounds, showed first-order biodegradation rate constants ranging from 0.57 to 0.90 per day (half-lives 1.2 to 0.80 days). WBC-2 sustained degradation without daughter product accumulation when repeatedly amended with RDX and lactate for a year. In microcosms with groundwater containing perchlorate and nitrate, RDX degradation began without delay when bioaugmented with 10% WBC-2. Slower RDX degradation occurred with 3% or 5% WBC-2 amendment, indicating a direct relation with cell density. Transient RDX daughter compounds included methylene dinitramine, MNX, and DNX. With WBC-2 amendment, nitrate concentrations immediately decreased to near or below detection, and perchlorate degradation occurred with half-lives of 25–34 days. Single-well injection tests with WBC-2 and lactate showed that the onset of RDX degradation coincided with the onset of sulfide production, which was affected by the initial perchlorate concentration. Biodegradation rates in the pilot injection tests agreed well with those measured in the microcosms. These results support bioaugmentation with an anaerobic culture as a remedial strategy for sites contaminated with RDX, nitrate, and perchlorate.en_US
dc.description.sponsorshipThis study was supported by the U.S. Army, White Sands Missile Range (WSMR), and the U.S. Army Environmental Command. We would like to thank Benito Avalos, WSMR, for logistical support and program management for the U.S. Army. Any use of trade, product, or firm names in this report is for descriptive purposes only and does not imply endorsement by the U.S. Government.en_US
dc.description.urihttps://www.sciencedirect.com/science/article/abs/pii/S0045653522001679?via%3Dihuben_US
dc.format.extent12 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m2de26-zrb3
dc.identifier.citation"Lorah, Michelle M. et al. Enhanced bioremediation of RDX and Co-Contaminants perchlorate and nitrate using an anaerobic dehalogenating consortium in a fractured rock aquifer. Chemosphere 294 (May 2022), 133674. https://doi.org/10.1016/j.chemosphere.2022.133674."en_US
dc.identifier.urihttps://doi.org/10.1016/j.chemosphere.2022.133674
dc.identifier.urihttp://hdl.handle.net/11603/24345
dc.language.isoen_USen_US
dc.publisherElsevieren_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Chemistry & Biochemistry Department Collection
dc.relation.ispartofUMBC Student Collection
dc.rightsThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.en_US
dc.rightsPublic Domain Mark 1.0*
dc.rights.urihttp://creativecommons.org/publicdomain/mark/1.0/*
dc.titleEnhanced bioremediation of RDX and Co-Contaminants perchlorate and nitrate using an anaerobic dehalogenating consortium in a fractured rock aquiferen_US
dc.typeTexten_US

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