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Table 2 Total soil heavy metals content of farmland

From: Bioaccumulation of heavy metals in soil and selected food crops cultivated in Kogi State, north central Nigeria

Properties Depth (cm) Farmland soils (n = 300) Control soils (n = 32) Regulated limits (mg/kg)
Range Mean SD Median Range Mean SD CCME (1999) EU (2002)
Cd 0–15 0.07–9.80 0.60 0.7 0.14 0.03–1.92 0.64 0.79 1.4 3.0
15–30 0.03–9.43 0.37 0.07 0.20 0.02–2.11 0.72 0.87
Co 0–15 0.05–38.1 6.0 7.1 4.31 1.09–3.83 2.6 1.1 40
15–30 0.16–36.4 4.9 3.2 3.09 0.02–5.68 2.5 1.8
Cu 0–15 0.33–16.9 4.8 3.9 4.38 1.08–8.17 2.7 2.4 63 140
15–30 0.32–12.9 1.5 2.4 3.13 0.32–7.72 2.5 2.4
Ni 0–15 3.81–93.1 17 14 13.7 4.43–18.5 9.6 5.2 50 75
15–30 3.28–68.4 12.8 1.5 11.9 3.20–12.6 8.3 3.9
Pb 0–15 4.45–47.7 12.8 8.2 12.1 3.79–13.7 6.1 3.2 70 300
15–30 3.21–30.3 11.7 2.2 12.1 2.31–19.0 5.7 5.5
Zn 0–15 5.02–81.4 28 23 17.9 7.46–28.5 11.6 6.9 200 300
15–30 4.67–84.4 25.0 8.5 16.2 6.12–20.2 9.8 4.6