The Distribution of Metals in Soils and Pore Water at Three U.S. Military Training Facilities

Abstract

Small arms firing ranges at military training facilities can have enormous heavy metal burdens (percent level) in soils.Currently there are few published works that quantify the metal content of soils and waters at military installations or speculate on the potential for migration of these contaminants into groundwater. This article documents metals in soils and waters at nine small arms training ranges at three military installations in the U.S. Soil samples were collected from the surface and shallow subsurface. The results demonstrated that lead, antimony, copper, and zinc were the principal contaminants of interest and mapping a site's lead and copper surface distributions would adequately define the extent of impacted soil. Lower metal concentrations at three of the ranges reflected previous remediation by means of physical separation and mechanical removal of metallic fragments followed by fixation treatment with Maectite TM . Except for the treated ranges where mixing had occurred, subsurface soil samples indicated limited vertical migration. Several of the ranges were also monitored for trace element migration in the vadose zone by means of suction-cup lysimeters. This pore-water sampling indicated ceramic suction-cup lysimeters are useful for assessing relative concentrations but require care in evaluation because of potential sorption losses. Monitoring of soil water at ranges should include antimony and zinc; the former because, in contrast to the other metals, it is typically soluble in an anionic form, and the latter because of its greater solubility and mobility.

Release and Biomethylation of Antimony in Shooting Range Soils upon Flooding

“…The analysis also revealed that the percentage of Sb from the bullets (1-5% Sb, 95-99% Pb) is conserved in the soil profiles of all three sites with Sb percentages of 1 to 5.2% calculated as 100 × Sb/(Sb + Pb). This result is similar to previously found ratios in shooting range soils [12,50]. Compared to the surface concentrations, the decreasing Sb and Pb concentrations with increasing depth in the soils at Sites B and C indicate that both elements are strongly bound in the OM-rich topsoil and little leached down the soil profile.…”

“…For Sb, these concentrations are well above soil background values of 0.3-8.6 mg kg −1 [48]. However, they are in line with previously found concentrations of Sb in shooting range and mining sites that range up to 17,500 mg kg −1 [5,8,22,34,49,50]. It must be noted, however, that extremely small bullet residues (<100 μm) can be present in the soil [4].…”

Antimony leaching from contaminated soil under manganese- and iron-reducing conditions: column experiments

“…[1] As a consequence, it is also increasingly released into the environment, potentially leading to soil contamination of more than several thousand milligrams per kilogram in places where it is mined, used and disposed of. [2][3][4] A major source of Sb input into the environment are shooting activities, as lead bullets contain ,2 to 5 % of metallic Sb as a hardener. [1,5] In Switzerland, for example, 10 to 25 tonnes (,10-25 Mg) of Sb enter the pedosphere every year on more than 2000 shooting ranges [6,7] ; and in the United States, shooting activities deposit ,1900 tonnes (,1.9 Gg) of Sb annually [8] on ,12 000 firing ranges.…”

Adsorption of Antimonate by Gibbsite: Reversibility and the Competitive Effects of Phosphate and Sulfate

“…Antimony concentrations in military and civilian shooting range soils have been reported to range from <517 to <17,500 mg kg −1 (Basunia and Landsberger, 2001;Johnson et al, 2005;Kilgour et al, 2008;Knechtenhofer et al, 2003;Mitsunobu et al, 2006;Okkenhaug et al, 2013;Spuller et al, 2007), although Scheinost et al (2006) re-ported values that approached 100,000 mg kg −1 . These excessive soil concentrations have also been reported to generate elevated Sb concentrations in pore water (Clausen and Korte, 2009;Lewis et al, 2010;Okkenhaug et al, 2013).…”

“…Antimony is a hardening agent in lead bullets, which contain ~5% Sb (Carlin, 2000;Johnson et al, 2005;Kilgour et al, 2008). As bullets and bullet fragments corrode, Pb and Sb are released to the soil environment (Clausen and Korte, 2009;Kilgour et al, 2008). The resulting Sb concentrations can far exceed native soil levels.…”