Speciation and mobility of lead in shooting range soils

Figures & data

Table 1. Shooting ranges years of establishment and the corresponding soil types found at the seven shooting ranges located in the eastern and northern Botswana.

Range location	Year of establishment	Soil classification
S/P PISTOL	2001	Haplic luvisols
S/P R2	2001	Haplic luvisols
S/P R1	2001	Haplic luvisols
MAT R2	1985	Chromic luvisols
MAT R1	1985	Chromic luvisols
LEBO	1987	Pellic vertisols
TSHU	1984	Pellic vertisols

Figure 1. (a) Location of shooting ranges sampled in the eastern and northern Botswana. (b) Map of Africa showing countries. Source: Worldatlas.com.

Figure 2. Schematic of sampling points in the shooting range.

Figure 3. Total Pb concentrations of composite soils taken from; (a) the berm; (b) target line; (c) 50 m from target line and (d) 100 m from target line at seven different shooting ranges found in the eastern and northern Botswana, Mean of n = 3; Standard error of the mean, δ = δ/√n, where δ = standard deviation.

Figure 4. Background-Pb concentrations at seven different shooting ranges found in the eastern and nothern Botswana (background soil was taken at 200 m away from the shooting range). Mean of n = 3; Standard error of the mean, δx̄ = δ/√n, where δ = standard deviation.

Figure 5. Sequential extraction of Pb into different chemical fractions found in soils from shooting ranges located in the eastern and nothern Botswana.

Notes: WE = water-soluble and exchangeable, OB = organic-bound, CB = carbonate-bound, FM = Fe-Mn oxides bound and RS = residual fraction.

Table 2. Chemical properties of soils found in seven shooting ranges located in the eastern and northern Botswana.

Range	pHw ± δ^a	Organic matter (%) ± δ	CEC^b ± δ
S/P PISTOL	6.81 ± 0.01	0.52 ± 0.11^c	8.20 ± 0.11
S/P R2	8.20 ± 0.01	0.88 ± 0.15	10.24 ± 0.22
S/P R1	7.30 ± 0.01	0.65 ± 0.01	11.93 ± 0.21
MAT R2	8.36 ± 0.02	2.13 ± 0.02	21.87 ± 0.07
MAT R1	8.69 ± 0.01	1.32 ± 0.01	20.60 ± 0.24
LEBO	7.50 ± 0.01	1.10 ± 0.11	27.05 ± 0.31
TSHU	7.55 ± 0.01	0.31 ± 0.08	9.26 ± 0.22

^a δ = Standard deviation.

^b Cation exchange capacity.

^c Mean ± standard deviation (n = 3).

Figure 6. (a) Mobility factor (%) and (b) Bioavailability factor (%) of Pb indicating the mobility and migration of Pb in the berm soil and possible biovailability of Pb to plants growing near the seven shooting ranges found in eastern and nothern Botswana.

Figure 7. Synthetic precipitation leaching procedure (SPLP) Pb concentrations at seven different shooting ranges found in the eastern and northern Botswana (SPLP experiments simulate the effect of acid rain on chemical Pb transformation).

Note: Mean of n = 3; Standard error of the mean, δx̄ = δ/√n, where δ = standard deviation.