Military test and training ranges are key elements in maintaining the capability and readiness of the U.S. Armed Forces. However, millions of acres of range sites are potentially contaminated with unexploded ordnance (UXO), including bombs, missiles, and landmines. Depending on site conditions and UXO characteristics, the time to perforation (i.e., corrosion breakthrough of the UXO metallic casing) can vary from roughly 10 years to several thousand years. The potential movement of energetic materials out of perforated UXO and into groundwater has become a primary environmental concern.
The objectives of this project were to (1) collect and analyze soil and UXO scrap metal samples from several ranges across the country, (2) develop a physically based correlation for the perforation rate of UXO under a variety of soil and climatic conditions, and (3) collect and analyze soil samples around the UXO for explosives.
Field data characterizing UXO metal scrap and surrounding soils were collected from various range sites undergoing clearance by the U.S. Army Corps of Engineers. Only sites with ordnance of known age were evaluated so that corrosion rates could be determined. This project included sampling of UXO and soils under various environmental conditions and simultaneous development of a technically sound UXO corrosion model, which forecasts the time to perforation based on site-specific soil and climatic conditions.
A simple protocol was developed for environmental sampling of UXO corrosion and energetic presence in soil. Using this protocol, a database was developed with site characteristics, sampling results, and pictures of UXO items at 14 sites. The UXO corrosion model, which was validated by extensive data from this study and previous studies at other military sites, was integrated into soon-to-be-released Department of Defense (DoD) software to facilitate its use by DoD environmental risk assessors. In addition, a UXO energetic release and transport model was developed to predict groundwater loading of energetics released from buried sources.
Understanding the corrosion rate is the first element necessary to maintaining the long-term viability of active ranges and developing a risk-based priority system. Extensive field data will assist future users, providing a basis for predictive models and risk assessments, to ensure the cost-effective management and long-term viability of military test and training ranges.