Table 6 The heavy metal content in surface (0–30 cm).
Heavy metal | Detection range (mg/kg) | Average value (mg/kg) | Coefficient of variation (%) | Average number of exceedances | Average exceedance rate (%) | Standard value (mg/kg) |
|---|---|---|---|---|---|---|
Cd | 1.25–19 | 8.583 | 0.51 | 14.31 | 100 | 0.6 |
As | 229–4030 | 1560.6 | 0.58 | 62.424 | 100 | 25 |
Pb | 89.25–300 | 193.35 | 0.27 | 0 | 86.6 | 140 |
Cr | 121.5–269.75 | 200.67 | 0.23 | 0 | 0 | 300 |
Cu | 101.25–1440.75 | 263.26 | 0.92 | 0 | 43.3 | 200 |
Ni | 64–289.5 | 127.23 | 0.43 | 0 | 60 | 100 |
Zn | 339.25–1391.75 | 848.32 | 0.38 | 0 | 100 | 250 |
