Optimization and Field Demonstration of a Passive Sampling Technology for Monitoring Conventional Munition Constituents in Aquatic Environments

As a result of military training and weapon testing activities, unexploded ordnance (UXO; including munitions such as bombs, projectiles, and mines that did not function as intended) are present in underwater environments. Munitions are also present at underwater sites as discarded military munitions (DMM). In addition to explosive safety considerations, regulators are increasingly concerned about potential ecological impacts on the aquatic environment following corrosion and breaching shells that may cause the slow release of the explosive material by dissolution to the surrounding sediments and water column. Challenges such as the high level of effort required to identify leaking munitions and potential for slow and intermittent release resulting in ultralow concentrations (i.e., part per trillion) may hinder the assessment of environmental exposures using traditional water sampling and analysis techniques. Recently, integrative passive samplers, specifically polar organic chemical integrative samplers (POCIS), have been demonstrated by our team to be valuable tools for the environmental exposure assessment of munition constituents (MC) in aquatic environments. POCIS can be deployed for weeks to months and continuously sample the water, providing the opportunity to capture episodic events or fluctuations in contaminant release, even at low concentrations. The resulting time-weighted average (TWA) water concentration can then be compared with screening values in the context of ecological risk potential and relevance for remedial action. Our preliminary results from POCIS employed under field conditions indicate that it is a robust approach to understanding and validating the release and transport behaviors of MC and subsequent exposure characterization in the vicinity of potentially breached UXO or DMM in ocean environments.