Behavior of energetic materials in ground water at an anti-tank range.

An environmental issue has arisen with M-72 malfunction on anti-tank ranges because many of these rockets break into pieces without exploding on impact, dispersing their energetic materials content on the ground surface and exposing them to transport by infi ltration of rainfall and snowmelt. A case study (1998–2005) at Arnhem Anti-Tank Range (Garrison Valcartier, Canada, in operation since the 1970s) revealed octahydro-1,3,5,7tetranitro-1,3,5,7-tetrazocine (HMX) contamination and traces of 1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) in ground water at varying concentrations, with all detected HMX concentrations below the USEPA guideline for drinking water of 400 μg L−1. An HMX mass balance on a transect perpendicular to ground water fl ow, about 300 m downgradient of the impact area, indicated an HMX fl ux of about 3 g d−1 (0.7–1 kg yr−1, 2005). Th e HMX mass in the impact area on the sand terrace was estimated at 7 to 10 kg (in 2005). Th e annual dissolved HMX fl ux represents about 10% of the source. Th e dissolved HMX plume in ground water consisted of a series of slugs, generated at each signifi cant infi ltration event. HMX is weakly retarded by sorption and is neither biotransformed nor mineralized under the aerobic conditions of the aquifer. TNT and RDX exceeded the USEPA guideline (2 μg L−1 RDX and 1 μg L−1 TNT) in three and two samples, respectively. Th e TNT plume was discontinuous because this compound was not always present at the ground surface. TNT is biotransformed, weakly sorbed, and not mineralized. In two wells, perchlorate associated with the propellant was found at concentrations above the Health Canada preliminary guideline of 6 μg L−1 near the fi ring position. Behavior of Energetic Materials in Ground Water at an Anti-Tank Range