Lead contamination of soil in the vicinity of a military shooting range in Ibadan, Nigeria

Abstract

Contamination at shooting range is increasingly of concern due to the accumulation of lead from bullet fragments in soil. This study investigates the degree of contamination in and around the Ibadan military shooting range, Nigeria. A total of 220 soil samples were collected in and around the range. At the core-range area, average Pb (5680 ± 2700 mg kg⁻¹) level in topsoil at the berm was significantly higher than other locations representing 280 times the background. Lead levels at the surrounding vicinity were similar to the control sites. Parametric t-test (95% confidence limit) showed no significant difference in Pb levels between the topsoil and subsoil. Concentrations of Cu and Cd were similarly higher at the berm. Inter-element correlation coefficient was generally high (0.70–0.93) except for Ni and Cr. This indicates that Ni and Cr were not influenced by shooting activities. Principal component analysis showed that metal levels at the berm, target basement, 100 m and 200 m firing lines accounted for 74.7% of the overall metal load of the soil. Correspondent analysis gave the degree of contamination in the order of Pb > Cd > Cu > Ni > Cr. There was evidence of contamination around the berm. Mitigation measures are required to minimize the current level of contamination.

Keywords:

• soil contamination
• lead
• bullet
• shooting range
• accumulation factor
• principal component analysis