Transport of Composition B in Overland Flow and Soil Solution

Abstract

Energetics used in military exercises can potentially contaminate ground and surface waters. This study was conducted to evaluate the movement of Composition B, a formulation that includes TNT (2,4,6-trinitrotoluene), RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), in overland flow. Rainfall simulations were conducted under controlled conditions with two rainfall rates (approximately 30 and 50 mm h-1), two soils (Florence loam from Arizona and Sassafras loam from Maryland), and several energetic particle sizes (4.75 - 9.51 mm, 2.83 - 4.75 mm, 2 - 2.83 mm, and, 2.83 mm, and <2 mm). Particles remaining on the soil surface after rainfall were measured as well as energetics in solution in the overland flow, in suspended sediment, and in infiltration. Greater concentrations of TNT than RDX and HMX were found in runoff due to its higher solubility. We also found that particle transport in overland flow increased with decrease in particle size. Smaller particle sizes also lead to greater transport in solution. These results will help in determining the contamination potential of Composition B.