Estimation of the amounts of residues resulting from the high-order detonation of munitions is complicated by the presence of residues from previous detonations and the inability to easily obtain adequately sized samples to overcome spatial heterogeneity in residue deposition. This study was conducted to assess the use of snow-covered ranges to provide these types of estimates.

Two snow-covered ranges were used to estimate the amount of explosives residues that resulted from detonation of individual mortar rounds and hand grenades. At Fort Drum, NY, 60-mm mortars were fired and hand grenades thrown; at Camp Ethan Allen, VT, 81-mm mortars were detonated by EOD personnel using C4 (RDX) and a blasting cap, and 120-mm mortars were fired. The locations where residues were deposited were identified by the presence of black soot from the detonation of TNT on the surface of the otherwise clean snow. Large surface snow samples were collected with a snow shovel, the snow was melted and filtered, the water and filtered soot were extracted separately, and both extracts analyzed by gas chromatography with an electron capture detector (GC-ECD) and reversed-phase high performance liquid chromatography with an ultraviolet detector (RP-HPLC-UV).

The main charge in these four munitions was Composition B (60% RDX and 39% TNT). The amounts of residues of explosives deposited were very small, but detectable, in all cases. RDX accounted for most of the residue deposited, with lesser amounts of HMX and TNT. The major advantages of using snow-covered ranges for these estimates were: (1) the snow cover provided an uncontaminated surface, unaffected by previous detonations, (2) the black soot produced from the detonation of TNT delineated the areas of residue deposition, and (3) surface snow provides a convenient matrix for collection of large surface area samples, essential for characterization of heterogeneously distributed residues.