Soil Microbial Activity Benchmarks (provisional) for Ecological Risk Assessments at Explosives-contaminated Sites: Promoting Range Sustainability

The Army Strategy for the Environment applies an ecosystem approach to managing natural resources on Army installations. It incorporates the principles of sustainability across the Army into all functional areas. We conducted investigations to develop critical data required for successful management of Army installations in a sustainable manner and for the knowledge-based decision making. Assessment and protection of the terrestrial environment at Army testing and training ranges is being advanced by developing and applying scientifically based ecotoxicological benchmarks that identify concentrations of energetic materials (EM) in soil that present an acceptable ecological risk for biologically-mediated processes in soil. Without such ecotoxicological benchmarks, the current state of knowledge concerning the nature and extent of residual contamination with EM at Army installations is insufficient to ensure management of training and testing ranges as sustainable resources. We investigated the effects of the nitrogen-based organic EM compounds 2,4-dinitrotoluene (2,4-DNT), 2aminodinitrotoluene (2-ADNT), 4-aminodinitrotoluene (4-ADNT), and nitroglycerin (NG) on soil function endpoints, including litter decomposition and the enzymatic activity, in Sassafras sandy loam (SSL) soil individually amended with nominal EM concentrations ranging from 10 to 10000 mg/kg. Benchmark data will be made available for use in Ecological Risk Assessment of terrestrial habitats at Army testing and training sites.