PH05 Fate and Effects of Energetic Compounds
Exhibit Hall
8:00 AM - Thursday
(PH024) Derivation of toxicity reference values for the acute and chronic toxicity of RDX to marine organisms.
Gensemer, R.1, Caldwell, R.2, Paulus, S.3, Crawford, P.4, 1 Parametrix, Corvallis, OR, USA2 Northwestern Aquatic Sciences, Newport, OR, USA3 ENSR, Redmond, WA, USA4 U.S. Army, Fort Lewis, WA, USA
ABSTRACT- Royal detonation explosive (RDX; hexahydro-1,3,5-trinitro-1,3,5-triazine) is a commonly used military explosive that has the potential to be transported into aquatic environments. Risks to aquatic organisms exposed to RDX in surface waters are relatively well understood for freshwater organisms, but few data exist regarding the acute or chronic toxicity of RDX to marine organisms. Therefore, we evaluated the toxicity of RDX to eight species of marine organisms to provide a toxicity database sufficient to derive toxicity reference values according to standard USEPA methods for calculation of ambient water quality criteria for protection of aquatic life. Acute toxicity tests were conducted with three fish species (Cyprinodon variegatus, Menidia beryllina, and Pleuronectes vetulus), five invertebrate species (Mytilus galloprovincialis, Americamysis bahia, Cancer magister, Dendraster excentricus, and Neanthes arenaceodentata), and a marine alga (Skeletonema). An early life stage test with the sheepshead minnow, C. variegatus was also combined with existing freshwater chronic tests to derive a chronic toxicity threshold value. Preliminary results suggest that the acute toxicity of RDX to marine organisms is very similar to that of freshwater organisms. RDX was not shown to be acutely toxic to any of the marine invertebrates tested to date at concentrations less than maximum solubility (about 40-50 mg RDX/L), and median lethal effects concentrations for two of the marine fish (LC50s of 7.08 and 9.82 mg RDX/L for M. beryllina and C. variegatus, respectively) were very similar to toxicity values observed for the most acutely sensitive freshwater fishes (e.g., fathead minnows and bluegill sunfish). An EC50 of 10.6 mg RDX/L for Skeletonema was also similar to toxicity values for freshwater algae found in the literature. Therefore, toxicity thresholds for RDX exposure to marine organisms are likely to be similar to those already considered for freshwater species.
Key words: toxicity reference value, RDX, ambient water quality criteria, marine