Table 1 The classification criteria for EF, Igeo, and RI.
EF | Enrichment degree | \(\:{\varvec{I}}_{\varvec{g}\varvec{e}\varvec{o}}\) | Evaluation levels | \(\:{\varvec{E}}_{\varvec{r}}^{\varvec{i}}\) | \(\:\varvec{R}\varvec{I}\) | Potential ecological risk |
|---|---|---|---|---|---|---|
≤ 1 | No Enrichment (No Contamination) | ≤ 0 | No Contamination | ≤ 40 | ≤ 150 | Low |
1 ~ 2 | Slight Enrichment (Slight Contamination) | 0 ~ 1 | No to Moderate Contamination | 40 ~ 80 | 150 ~ 300 | Moderate |
2 ~ 5 | Moderate Enrichment (Moderate Contamination) | 1 ~ 2 | Moderate Contamination | 80 ~ 160 | 300 ~ 600 | Considerable |
5 ~ 20 | High Enrichment (Heavy Contamination) | 2 ~ 3 | Moderate to Heavy Contamination | 160 ~ 320 | ≥ 600 | High |
20 ~ 40 | Extremely High Enrichment (Severe Contamination) | 3 ~ 4 | Heavy Contamination | ≥ 320 | / | Very High |
/ | / | 4 ~ 5 | Heavy to Extreme Contamination | / | / | / |
/ | / | >5 | Extreme Contamination | / | / | / |
