Objective

Contamination of soils is a concern at many firearms training facilities. Lead is the primary metal of concern as it makes up approximately 90% by mass of a typical bullet and is a common constituent in rockets, mortars, grenades, and Howitzer rounds. In addition to lead, a number of other potentially toxic trace metals and metalloids are of concern. Bullet alloys generally include antimony, arsenic, bismuth and silver, and bullets are commonly encased in a copper or nickel jacket. Fragments of bullets and other munitions are highly susceptible to oxidation and weathering processes in soil systems, leading to the release of aqueous metal(loid) species into soils. The potential for metal(loids) stored in soils to migrate from shooting ranges into surface or subsurface aquatic systems is a public health concern. Detailed knowledge of the processes controlling mobilization versus retention of metal(loid) species associated with bullet fragment weathering in small arms training range soils is essential for assessing long-term environmental risk, for understanding the efficacy of remediation scenarios, and for identifying what materials to incorporate into future training range or impact area designs.

The objective of this project is to improve the molecular- and nano-scale understanding of metal(loid) transport and bioavailability in range soils (lead and antimony in particular) with a focus on the rates and geochemical mechanism(s) of metallic fragment weathering, the rate and extent of oxidized metal(loid) dispersion, how metal(loid) dispersion is correlated with speciation, and how rates and extent of reaction are influenced by soil properties.