Heavy metal in the soils of Pistol and Rifle Ranges

Outdoor pistol and rifle ranges have been under scrutiny from both the public and the state as these places have soils which are contaminated with heavy metals such as lead, zinc and antimony. Pistol and rifle ranges cannot be easily converted for other land uses due to heavy metal contamination, they have to be remediated before other usages can be deployed on these soils, especially for residential uses.

Pistol and Rifle ranges have very high possibility of accumulating Hardison, et al. (2003) examined lead contamination in shooting range soils from abrasion of lead bullets and subsequent weathering. This study showed that it is not just the weathering of lead bullets in soils which contribute to lead contamination in soils, even the abrasion of bullets in soils contributes significantly to lead contamination in soils.

Besides lead contamination, other heavy metals in bullets such as zinc and antimony (used as a hardener in bullets) also contaminate pistol and rifle range soils. These heavy metals complicate the process of soil remediation as these heavy metals are bioavailable at different environments. Lead is soluble in soils at low pH while Sb is at high pH.

Okkenhaug, et al. (2013) reported in a seminar that the largest source of pb and sb contamination (i.e. leach into the environment) in Norway is from shooting ranges. To stabilise pb and sb, they identified and used iron based sorbents to immobilise pb and sb in soils and later to be removed by mechanical means. This has been tested out in Norway, and may be useful in remediating pistol and rifle range soils for other land use purposes.

References

Hardison, D.W. Jr., et al. (2004) Lead contamination in shooting range soils from abrasion of lead bullets and subsequent weathering. Science of the total environment, Vol. 328, pp. 175-183.

Okkenhaug, G.; Amstätter, K.; Lassen Bue, Cornelissen, G.; Breedveld, G.D.; Mulder, J., Antimony (Sb) contaminated shooting range soil: Sb mobility and immobilization by soil amendments. Accepted with major revisions, Environmental Science & Technology.