PT02 Soil Toxicology and Risk Assessment
Exhibit Hall
8:00 AM - Tuesday, 11 November 2003
(PT019) Aquatic Ecotoxicity of the New Energetic Material CL-20: Preliminary Results.
Haley, M1, Kurnas, C1, Chester, N1, Anthony, J1, Kuperman, R1, Checkai, R1, 1 U.S. Army Edgewood Chemical Biological Center, APG, MD, USA
ABSTRACT- We are investigating the aquatic ecotoxicity of the new energetic material hexanitrohexaazaisowurtzitane (CL-20), a polycyclic nitramine compound similar to the explosives HMX and RDX but with a larger caged structure and greater energetic efficiency. We are using standard USEPA aquatic toxicity methods to assess the effects of CL-20 on the test organisms Ceriodaphnia dubia (water flea), Pimephales promelas(fathead minnow), and Selenastrum capricornutum (green single celled algae). We selected these bioassays on the basis of their ability to determine chemical toxicity to ecologically relevant species, and because they include at least one reproduction or growth component among the measurement endpoints. We designed experiments to include two types of exposure: (1) direct amendments of CL-20 to test media, and (2) aquatic elutriates from soils amended with various levels of CL-20. We selected these exposure routes to assess the potential toxicity of CL-20 if it becomes released into the aquatic environment. Preliminary results show that the order of CL-20 toxicity among the three species (beginning with greatest toxicity) in opening studies with direct amendments was: P. promelas, C. dubia, S. capricornutum, with provisional EC20 values of 0.2 mg/L (growth), 0.4 mg/L (reproduction), and 13 mg/L (growth), respectively. Elutriates from Sassafras Sandy Loam soil amended with CL-20 were prepared using an Adapted Toxicity Characteristic Leaching Procedure (ATCLP). The acetic acid solution required in the analytically-based Toxicity Characteristic Leaching Procedure (TCLP) was substituted in these ongoing studies with well water acidified by saturation with CO2. This modification allowed direct measurement CL-20 toxicity.
Key words: aquatic toxicity, soil extracts, ceriodaphnia, fathead minnow