Table 2.
Heavy metal concentration(s), pH and OM in paddy soil (mg kg−1).
| Elements | AM | Maximum | Minimum | CV (%) | Median | Standard Value a | Background Value b |
|---|---|---|---|---|---|---|---|
| As | 19.7 ± 17.1 | 129 | 1.08 | 76.65 | 15.1 | 30 | 20 |
| Cd | 0.58 ± 0.69 | 6.23 | 0.16 | 151.93 | 0.42 | 0.4 | 0.659 |
| Cu | 40.5 ± 32.8 | 158 | 4.03 | 81.90 | 29.1 | 50 | 32 |
| Pb | 35.5 ± 32.0 | 290 | 12.4 | 57.34 | 27 | 100 | 35.2 |
| Zn | 135 ± 128 | 907 | 48.8 | 106.34 | 94.5 | 200 | 99.5 |
| pH | 6.5 ± 0.3 | 7.1 | 5.6 | 5.1 | 6.5 | null | 6.2 |
| OM | 5.2 ± 2.0 | 10.3 | 1.7 | 38.5 | 4.8 | null | 4.3 |
a From provisions on the limits of heavy metals in agricultural lands in the Soil Environmental Quality Standards of the People’s Republic of China (GB 15618-2018); b The soil background value of Guizhou Province comes from CNEMC (1990).; C V: Denotes the coefficient of variation; AM: Denotes the arithmetic mean; OM: organic matter.