Soil Invertebrate and Terrestrial Plant Based Toxicity Benchmarks: Bioavailability and Ecological Soil Screening Levels for Energetic Materials.

Department of Defense (DoD) in 2002 identified 2,307 explosives-contaminated sites.  According to the GAO, in 2003 more than 15 million acres in the USA were suspected or known to be contaminated with military munitions, with assessment and cleanup efforts estimated to cost $8-35 billion and take >75 years.  Soil contaminated with explosives may pose significant risks to military personnel, the surrounding environment, and potentially to offsite human and ecological receptors.  Therefore, explosives-contaminated soils could potentially jeopardize the long-term sustainability of ranges and training sites.  Prerequisites for Troop readiness involve intensive training and testing, and such ranges remain key elements in maintaining capability, readiness, and interoperability of the Armed Forces; plus base closures (BRAC), and other military operations, also require environmental assessments.  The state of knowledge of ecological risks at ranges was inadequate to ensure their sustainable use.  At the request of USEPA and DoD, the Strategic Environmental Research and Development Program (SERDP) funded multiple research projects to determine the toxicities of energetic materials (EMs), for developing Ecological Soil Screening Levels (Eco-SSL).  Within our research we:  1) determined the toxicities of major nitramine and nitroaromatic EMs to soil invertebrates and terrestrial plants utilizing soils that support high relative bioavailability of EM; 2) integrated the effects of EM weathering-and-aging in soil on organism exposures and toxicity benchmarks; 3) developed Eco-SSL values for ecologically relevant soil receptors for use in Screening Level Ecological Risk Assessment (SLERA) for Superfund sites.  Eco-SSL values (mg/kg), for upland aerobic soils, awaiting formal approval by USEPA are for soil invertebrates 72 (RDX), 16 (HMX), 0.09 (CL-20), 15 (TNT), 18 (2,4-DNT), 7 (2,6-DNT), 18 (TNB), 43 (2-ADNT), 18 (4-ADNT), 13 (NG), and for plants 71 (RDX), NT (HMX),  NT (CL-20), 8 (TNT), 6 (2,4-DNT), 5 (2,6-DNT), 9 (TNB), 14 (2-ADNT), 33 (4-ADNT), 21 (NG); NT = not-toxic ≤10,000 mg/kg.