Risk Assessment and Ecotoxicological Support, Milan Army Ammunition Plant


Risk Assessment and Ecotoxicological Support, Milan Army Ammunition Plant

U.S. Army Corps of Engineers, under contract to Plexus Inc.


  • Integration of HRA and ERA evaluations with an array of site-specific toxicity test results
  • Supported elimination of need to landfill contaminated soils
  • Allowed for land application of composted materials
  • Achieved cost savings to the government of $1.4M over the life of the remediation project.

“Thanks in part to Avatar’s consistent and cost effective support, Plexus has grown significantly since 1999 and has won and successfully executed contracts with several USACE Districts … We look forward to continuing our relationship.” — Peter Tuebner (Plexus V.P. – Environmental Services and Remediation)


Avatar provided human health risk assessment, ecotoxicological analysis, and interpretation expertise to Plexus Scientific Inc. in support of the U.S. Army Corps of Engineers’ mission to detoxify munitions-contaminated soil at the Milan Army Ammunition Plant in Milan, Tennessee. The purpose was to determine if it was appropriate to discontinue the expensive practice of landfilling these soils and to allow for the land application of the composted materials.

Avatar performed a screening human health assessment of current and future use scenarios associated with the land application of these munitions-contaminated soils. Avatar also reviewed soil elutriate toxicity tests that were conducted on composted soils containing varying levels of TNT, tetryl, RDX, HMX and metabolic byproducts of the incomplete mineralization of these compounds. Tests conducted included chronic 7-day Ceriodaphnia dubia growth and survival studies, the Ames genotoxicity tests using Salmonella typhirium, which evaluates potential mutagenicity, and Microtox? algal bioluminescence assays, which serve as an indicator of potential physiological impairment. This work provided supporting documentation for the decision to allow the land application of these composted soils, including their use as a nitrogen source for agricultural fields, and to discontinue landfilling.