Quantitative assessment of environmental risk from lead pollution of shooting range soils

Figures & data

Figure 1. (a) Location of shooting ranges sampled in the eastern and northern Botswana. (b) Map showing southern african countries.

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

Table 1. Risk assessment code (RAC) and corresponding pollution risk level [22].

Risk assessment code range	Risk assessment code	Risk level
RAC < 1%	1	No risk
1% < RAC ≤ 10%	2	Low risk
11% ≤ RAC ≤ 30%	3	Medium risk
31% ≤ RAC ≤ 50%	4	High risk
RAC ≥ 51%	5	Very high risk

Table 2. Ecological risk index and resultant ecological risk level [26].

Ecological risk index	Ecological risk level
<40	Low
40 < Er ≤ 80	Moderate
80 < Er ≤ 160	Considerable
160 < Er ≤ 320	High
Er ≥ 320	Very high

Table 3. Classification of pollution risk into I_geo grades [27].

Igeo Index	Grade	Pollution risk
<0	1	Practically unpolluted
0 < Igeo < 1	2	Unpolluted to moderately polluted
1 < Igeo < 2	3	Moderately polluted
2 < Igeo < 3	4	Moderately to heavily polluted
3 < Igeo < 4	5	Polluted
4 < Igeo < 5	6	Heavily to extremely polluted
Igeo > 5	7	Extremely polluted

Table 4. Classification of individual metal contamination level [29].

Contamination Factor (CF)	Contamination level
CF < 1	Low contamination
1 ≤ CF < 3	Moderate contamination
3 ≤ CF ≤ 6	Considerable contamination
CF > 6	Very high contamination

Table 5. Categories of level of soil enrichment from Pb [29].

EF	Level of enrichment
<1	No enrichment
1 ≤ EF < 3	Minor enrichment
3 ≤ EF < 5	Moderate enrichment
5 ≤ EF < 10	Moderately severe enrichment
10 ≤ EF < 25	Severe enrichment
25 ≤ EF < 50	Very severe enrichment
EF ≥ 50	Extreme enrichment

Table 6. Eco-toxicity and bioavailability of Pb in the different fractions [31].

Fraction of Pb using Tessier method	Eco-toxicity	Bioavailability
Water exchangeable (WE) and carbonate bound (CB)	Direct toxicity	Direct effect fraction
Fe-Mn oxide (Fe-Mn) and organic bound (OB)	Potential toxicity	Potential effect fraction
Residual fraction (RS)	No toxicity	Stable fraction

Figure 3. RAC of Pb in berm soils of seven shooting ranges found in eastern and nothern Botswana. Mean of n = 3; Standard error of the mean, δ= δ/√n, where δ = standard deviation.

Figure 4. Potential ecological risk index (EPbr) of berm soil Pb of seven shooting ranges found in eastern and nothern Botswana. Mean of n = 3; Standard error of the mean, δ = δ/JK, where δ = standard deviation.

Figure 5. Geoaccumulation index (Igeo) of berm soil Pb of seven shooting ranges found in eastern and nothern Botswana. Mean of n = 3; Standard error of the mean, δ = δ/√n, where δ = standard deviation.

Figure 6. Contamination factor (CF) of berm soil Pb of seven shooting ranges found in eastern and nothern Botswana. Mean of n = 3; Standard error of the mean, δ = δ/√n, where δ = standard deviation.

Figure 7. Enrichment factor (EF) of berm soil Pb of seven shooting ranges found in eastern and nothern Botswana. Mean of n = 3; Standard error of the mean, δ = δ/√n, where δ = standard deviation.

Table 7. Pearson correlation coefficient (r) range and corresponding significance [24].

Pearson correlation coefficient range	Significance
0.5 to 1.0 or −0.5 to −1.0a	High correlation
0.3 to 0.5 or −0.3 to −0.5	Medium correlation
0.1 to 0.3 or −0.1 to −0.3	Low correlation

aA high negative Pearson correlation coefficient implies a direct negative correlation between two variables.

Figure 8. Pearson correlation between; (a) soil pH; (b) soil organic matter and (c) soil CEC to total Pb concentration of seven shooting ranges found in eastern and nothern Botswana. Mean of n = 3; Standard error of the mean, δ = δ/√n, where δ = standard deviation.

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