PARENT SESSION

WA6 Fate and Effects of Energetic Compounds
202 Oregon Ballroom
8:00 AM - 12:00 PM, Wednesday

() Transport and fate of the new cyclic nitramine energetic material CL-20 in a natural soil.

Checkai, Ronald ¹, Kuperman, Roman¹, Phillips, Carlton¹, Simini, Michael ¹, Anthony, J. ¹, Kolakowski, Jan¹, Kurnas, Carl ¹, Davis, Emily ¹, ¹ U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD USA, USA

ABSTRACT- We are investigating transport and fate of the new cyclic nitramine energetic material CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, -polymorph) in a natural sandy loam soil using an improved system adapted from the ASTM standard soil microcosm design. This system is the Controlled Environment Soil-core Microcosm Unit (CESMU; 1993). One major design modification was applying a controlled tension (30-35 kPa) equally at the bottom of each intact soil-core across a controlled-pore ceramic plate, comparable to that encountered in the field as a result of gravitational and matric forces. This prevents artificial build-up of water within columns, which can otherwise change the chemical, physical, and biological properties of soil. During preliminary studies we used the intact soil-core configuration and a compressed-time approach to investigate the potential for primary CL-20 crystals moving from contaminated surface soil through 30-cm intact soil core, during the 8-month study period planned for more definitive investigation. We implemented the compressed-time strategy by administering the equivalent of 8-months precipitation during a 2-week period, maximizing potential for hydrodynamic transport. Then we determined the resulting CL-20 concentrations in soil at increasing depths. The uppermost centimeters of soil retained almost all of the CL-20. Low concentrations of CL-20 corresponding to exceptionally small trace quantities in soil were found below the 25-cm depth. Preliminary results indicate that CL-20 transport through soil is primarily due to dissolution and subsequent partitioning between soil and pore water. CESMU methodologies allow us to more accurately assess CL-20 transport and fate in the soil vadose zone during the ongoing 8-month investigation. CL-20 that partitions into water is being assessed by analyzing both soil leachates and CL-20 uptake into plant tissues of perennial ryegrass Lolium perenne grown in the same contaminated soil. These investigations will provide information that is critical for assessing potential impacts of accidental release of CL-20 in the environment.

Key words: soil, CL-20, transport, fate