11 Sep 2025

Effect of Gypsum on Transport of IMX-104 Constituents in Overland Flow Under Simulated Rainfall

Abstract: Residue of energetic formulations, deposited on military training grounds following incomplete detonation, poses biotic hazards. This residue can be transported off-site, adsorb to soil clays and organic matter, transform or degrade, or taken up by plants and animals. Its harmful effects can be mitigated by localizing the energetics at the initial deposition using soil amendments and allowing them to bio- and photodegrade in situ. Small plots with coarse loamy soil were used to study the effect of gypsum on transport and redistribution under simulated rainfall of various sizes of insensitive munition explosive IMX-104 particles. The addition of gypsum more than doubled infiltration and decreased sediment loss by 16%. The post-rainfall mass balance of IMX-104 in the order from greater to smaller pools was: (1) soil surface retention, (2) off-site loss to overland flow, and (3) sub-surface infiltration. The application of gypsum decreased concentration and the total mass loss of dissolved DNAN, RDX, and HMX in surface runoff. In addition, gypsum significantly decreased or delayed the peak discharge of <2mm particulate energetics. Gypsum shifted the total mass balance of energetics toward subsurface flow. This study indicates gypsum may decrease off-site transport of energetic constituents in the soils subject to surface sealing.