title: RDX loss in a surface soil under saturated and well drained conditions.
abstract: On military training ranges, low-order, incomplete detonations deposit RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) into surface soils. In this study, we evaluated RDX biodegradation in surface soils obtained from a military training range in Alaska. Two factors were compared: (i) soil water potential during the incubations; and (ii) the use of acetonitrile (ACN) as an RDX carrier to spike samples. Organic solvents have been used in laboratory studies to dissolve slightly water-soluble contaminants before addition to soil. We added ACN to obtain final soil ACN concentrations of 0 mg kg(-1) (0%), 1000 mg kg(-1) (0.1%) and 10 000 mg kg(-1) (1%). We then compared RDX attenuation in the soil under saturated and unsaturated conditions. RDX fell below the limit of detection within 3 wk of study initiation under the saturated condition. A maximum degradation rate of 0.15 mg RDX L(-1) d(-1) was measured. Under the unsaturated condition, 42% of the original RDX was still present at study termination (5 wk). The addition of acetonitrile at 0.1 or 1.0% had no affect on RDX loss in the saturated soil. In the unsaturated soil, however, ACN at 1.0% inhibited RDX loss by as much as 25%. These findings indicate that soil water potential and carrier solvent concentrations can impact the rate and extent to which RDX is attenuated in a surface soil.
authors.affiliation: U.S. Army ERDC-CRREL, 72 Lyme Rd., Hanover, NH 03755, USA. David.B.Ringelberg@erdc.usace.army.mil
authors.forename: D B
authors.initials: DB
authors.lastname: Ringelberg
authors.forename: C M
authors.initials: CM
authors.lastname: Reynolds
authors.forename: M E
authors.initials: ME
authors.lastname: Walsh
authors.forename: T F
authors.initials: TF
authors.lastname: Jenkins
mesh_terms: D000097:Acetonitriles / Q000737:chemistry*; D001673:Biodegradation, Environmental; D004784:Environmental Monitoring; D015203:Reproducibility of Results; D012378:Rodenticides / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D014227:Triazines / Q000378:metabolism*; D014867:Water
chemical_list: D000097:Acetonitriles; D012378:Rodenticides; D012989:Soil Pollutants; D014227:Triazines; D014867:Water; C009160:cyclonite; C032159:acetonitrile