Fragmentation and Distribution of Lead Following Firing into Various Types of Range Soils

The extent of bullet fragmentation, among other factors, affects the formation of mobile metal species on small arms firing ranges. Impact fragmentation produces an increase in the surface area to mass ratio of the metal alloys in the soil. This study examined the results of this increase in six soil types. Larger percentages of the average mass of metal particulates passing through a 1.68 mm sieve were observed for rocky and sandy soils than for softer, less compressible soils. Soil particle size separation by wet sieve analysis demonstrated that <1.8% of the total amount of lead introduced by ammunition was present in the <0.45 micron (soluble) size fraction. Bullet fragmentation patterns indicate that fragmentation at a firing distance of 25 m is greater than that at 98.5 m. The particulate nature of metals, such as lead, results in extensive sample heterogeneity and a consequent broad range of metal concentrations.