Table 2 Total soil heavy metals content of farmland
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 | |||