| Index | Category | Description | Reference |
| Contamination factor Cf | Cf < 1 | Low contamination | [14] [16] |
| 1 ≤ Cf < 2 | Low to moderate contamination | ||
| 2 ≤ Cf < 3 | Moderate contamination | ||
| 3 ≤ Cf < 4 | Moderate to high contamination | ||
| 4 ≤ Cf < 5 | High contamination | ||
| 5 ≤ Cf < 6 | High to very high contamination | ||
| Cf ≥ 6 | Extreme contamination | ||
| Ecological risk factor (Er) | Er < 40 | Low risk | [17] [18] |
| 40 ≤ Er < 80 | Moderate risk | ||
| 80 ≤ Er < 160 | Considerable risk | ||
| 160 ≤ Er < 320 | High risk | ||
| Er ≥ 320 | Very high risk | ||
| Potential Ecological Risk Index (RI) | RI < 150 | Low risk | [19] [20] |
| 150 ≤ RI < 300 | Moderate risk | ||
| 300 ≤ RI < 600 | Considerable risk | ||
| RI ≥ 600 | High risk |