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The geoaccumulation index range and corresponding contamination level.
| Igeo | Level Risk | Contamination Level |
|---|---|---|
| <0 | Uncontaminated | 0 |
| 0–1 | Uncontaminated/moderately contaminated | 1 |
| 1–2 | Moderately contaminated | 2 |
| 2–3 | Moderately/strongly contaminated | 3 |
| 3–4 | Strongly contaminated | 4 |
| 4–5 | Strongly/extremely contaminated | 5 |
| 5–6 | Extremely contaminated | 6 |
