Military testing and training ranges are vital for preparing troops for combat and for maintaining readiness. While these ranges are an important resource for military exercises, range managers must delicately balance the activities on these lands so training operations can proceed without the environmental consequences associated with repeated release of energetic compounds. Use of conventional weapons and explosives in live-fire military training can lead to release of munitions constituent residues (RDX, HMX, TNT, and perchlorate) which can migrate to groundwater and drinking water sources. Under the SERDP project Distribution and Fate of Energetics on DoD Test and Training Ranges (ER-1155), energetic residues at numerous Army installations were characterized. A comprehensive study of energetic compounds present at Navy, Air Force, and Marine Corps munitions and sites, however, was not conducted.
The objective of this study was to provide a greater level of understanding of the potential for deposition of energetic residues on Air Force, Navy, and Marine ranges and to identify those constituents posing an environmental concern.
The range use criteria set forth for this study indicated that data had to come from a U.S. controlled land range capable of live-fire testing and located in the United States. Data on actual munition expenditures were obtained from 13 Air Force ranges capturing the major continental United States training facilities under the Air Combat Command (ACC), Air Education and Training Command (AETC), Air Force Materiel Command (AFMC), and Pacific Air Forces (PACAF). Ten-year projections also were obtained for 6 Navy and 3 Marine Corps sites that met the range use criteria set forth in this project. The basis for munition usage projection was the non-combat expenditure allowance (NCEA) from 2006 through 2015 for the Department of the Navy.
Different approaches were utilized to integrate the munitions usage data with munitions constituents present for Air Force, Navy and Marine ordnance items. For the Air Force assessment, the approach relied on using the national stock number (NSN) and the Department of Defense Identification Code (DODIC) numbers, where provided, to identify the munitions constituents. A similar approach used for the Navy and Marine information relied upon use of the NCEA number to look up the munition items, applying a DODIC number and then cross-referencing with the Naval Ammunitions Logistics Codes (NALC) in order to look up the item in the Munitions Items Disposition Action System (MIDAS).
The process used to quantify the HMX, RDX, TNT, and perchlorate contained in the munitions used on training range munitions was as follows:
The two energetic compounds present to the greatest extent in ordnance items used on Air Force training ranges were RDX and TNT. Much of the RDX and TNT was attributable to large bombs. The quantities of RDX and TNT were found to be as high as one to two million pounds per year for large ranges and could range into the tens of million pounds for multiple year totals.
The concern for groundwater and surface water impacts is primarily with RDX. The presence or absence in water will be a function of the depth to groundwater, degree of surface water drainage, soil characteristics, meteorological conditions, etc. However, those sites with fixed targets, shallow depth to groundwater, and high annual precipitation are sites having a high probability for movement of RDX from soil to water. In contrast, those sites with little precipitation and significant depths to groundwater have a low probability of surface water or groundwater impacts.
Generally it was found that the quantity of HMX and perchlorate, contained in the munitions, ranged between zero and several hundred pounds per year. The probability of HMX in surface water or groundwater was likely to be higher for the open burn/open detonation (OB/OD) and explosive ordnance disposal (EOD) training areas than for the bombing ranges. Also, it was found that Air Force installations using multiple launch rocket systems (MLRS) in training had the potential for perchlorate surface or groundwater impacts.
A significant quantity of munitions containing RDX and TNT were projected to be used by the Navy, and the most likely sources of energetic residues were determined to be demolition charges used at OB/OD and EOD training sites, medium caliber ammunition, and bomblets, where the risk and incidence of low-order reactions was high.
There was also a high potential for RDX, HMX, TNT and perchlorate introduction at Marine installations, with the greatest potential for surface and groundwater contamination at locations with significant precipitation.
In this study, training allocations and range records were merged with MIDAS. This approach provided an indication of the types of munitions used, as well as the location and quantity of energetic materials used, at live-fire training sites, and this technique could be applied to other emerging contaminants, as well. Information obtained in this project will allow the Department of Defense to identify those munitions and munitions constituents posing a threat to the environment and will aid range assessment studies and development of range sustainability plans.