title: Uptake and fate of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in coastal marine biota determined using a stable isotopic tracer, (15)N - [RDX].
abstract: Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is globally one of the most commonly used military explosives and environmental contaminant. (15)N labeled RDX was added into a mesocosm containing 9 different coastal marine species in a time series experiment to quantify the uptake of RDX and assess the RDX derived (15)N retention into biota tissue. The (15)N attributed to munitions compounds reached steady state concentrations ranging from 0.04 to 0.67 μg (15)N g dw(-1), the bulk (15)N tissue concentration for all species was 1-2 orders of magnitude higher suggesting a common mechanism or pathway of RDX biotransformation and retention of (15)N. A toxicokinetic model was created that described the (15)N uptake, elimination, and transformation rates. While modeled uptake rates were within previous published values, elimination rates were several orders of magnitude smaller than previous studies ranging from 0.05 to 0.7 days(-1). These small elimination rates were offset by high rates of retention of (15)N previously not measured. Bioconcentration factors and related aqueous:organism ratios of compounds and tracer calculated using different tracer and non-tracer methods yielded a broad range of values (0.35-101.6 mL g(-1)) that were largely method dependent. Despite the method-derived variability, all values were generally low and consistent with little bioaccumulation potential. The use of (15)N labeled RDX in this study indicates four possible explanations for the observed distribution of compounds and tracer; each with unique potential implications for possible toxicological impacts in the coastal marine environment.
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA. Electronic address: mark.ballentine@uconn.edu.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Ballentine
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Thivanka
authors.initials: T
authors.lastname: Ariyarathna
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Smith
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Cooper
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Penny
authors.initials: P
authors.lastname: Vlahos
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Fallis
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Groshens
authors.affiliation: University of Connecticut, Department of Marine Sciences, 1084 Shennocossett Road, Groton, CT 06340, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Tobias
mesh_terms: D059001:Aquatic Organisms / Q000737:chemistry / Q000378:metabolism*; D058448:Biota; D001711:Biotransformation; D053834:Explosive Agents / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D009587:Nitrogen Isotopes / Q000737:chemistry* / Q000378:metabolism; D014227:Triazines / Q000737:chemistry / Q000378:metabolism*
chemical_list: D053834:Explosive Agents; D009587:Nitrogen Isotopes; D014227:Triazines; C009160:cyclonite
keywords: Bioconcentration; Biotransformation; Hexahydro-1,3,5-trinitro-1,3,5-triazine; Isotopes; Nitrogen; RDX