title: Evaluation of microbial transport during aerobic bioaugmentation of an RDX-contaminated aquifer.
abstract: In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient bacterial transport tests of site groundwater containing chloride or bromide tracer and either a mixed culture of Gordonia sp. KTR9 (xplA (+)Km(R)), Rhodococcus jostii RHA1 (pGKT2 transconjugant; xplA (+)Km(R)) and Pseudomonas fluorescens I-C (xenB (+)), or a single culture of Gordonia sp. KTR9 (xplA (+); i.e. wild-type) were conducted at UMCD. Groundwater monitoring evaluated cell viability and migration in the injection well and downgradient monitoring wells. Enhanced degradation of RDX was not evaluated in these demonstrations. Quantitative PCR analysis of xplA, the kanamycin resistance gene (aph), and xenB indicated that the mixed culture was transported at least 3 m within 2 h of injection. During a subsequent field injection of bioaugmented groundwater, strain KTR9 (wild-type) migrated up to 23-m downgradient of the injection well within 3 days. Thus, the three RDX-degrading strains were effectively introduced and transported within the UMCD aquifer. This demonstration represents an innovative application of bioaugmentation to potentially enhance RDX biodegradation in aerobic aquifers.
authors.affiliation: U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA. Fiona.H.Crocker@usace.army.mil.
authors.forename: Fiona H
authors.initials: FH
authors.lastname: Crocker
authors.affiliation: U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Indest
authors.affiliation: U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
authors.forename: Carina M
authors.initials: CM
authors.lastname: Jung
authors.affiliation: U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
authors.forename: Dawn E
authors.initials: DE
authors.lastname: Hancock
authors.affiliation: CB&I Federal Services, 17 Princess Road, Lawrenceville, NJ, 08648, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Fuller
authors.affiliation: CB&I Federal Services, 17 Princess Road, Lawrenceville, NJ, 08648, USA.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Hatzinger
authors.affiliation: CB&I Federal Services, 17 Princess Road, Lawrenceville, NJ, 08648, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Vainberg
authors.affiliation: School of Civil and Construction Engineering, Oregon State University, Corvallis, OR, 97331, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Istok
authors.affiliation: Environmental Engineering & Technology Section, U.S. Army Corps of Engineers, Seattle, WA, 98134, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Wilson
authors.affiliation: Environmental Engineering & Technology Section, U.S. Army Corps of Engineers, Seattle, WA, 98134, USA.|U.S. Army Engineer Research and Development Center, Seattle, WA, 98134, USA.
authors.forename: Mandy M
authors.initials: MM
authors.lastname: Michalsen
mesh_terms: D000332:Aerobiosis; D001673:Biodegradation, Environmental; D053834:Explosive Agents / Q000378:metabolism*; D033601:Gordonia Bacterium / Q000378:metabolism*; D060587:Groundwater / Q000032:analysis / Q000382:microbiology*; D012240:Rhodococcus / Q000378:metabolism*; D014227:Triazines / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D053834:Explosive Agents; D014227:Triazines; D014874:Water Pollutants, Chemical; C009160:cyclonite
keywords: Bioaugmentation; Groundwater; Hexahydro-1,3,5-trinitro-1,3,5-triazine; Microbial transport; RDX