From: Heavy metal gradients from rural to urban lakes in central China
Group | EF | Â | Â | Â | Â | Â | Â | Â | Â | Â | Grade standards for EF | |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Mn | Cu | Zn | As | Ni | Cd | Pb | Co | Cr | Fe | Value | Enrichment status | |
A | 3.7 ± 0.8 | 6.9 ± 3.5 | 4.0 ± 0.6 | 1.7 ± 0.9 | 2.9 ± 1.0 | 7.9 ± 2.5 | 3.1 ± 0.9 | 3.9 ± 0.7 | 4.9 ± 2.9 | 3.0 ± 0.7 | < 1 | No enrichment |
B | 1.3 ± 0.1 | 4.5 ± 3.2 | 3.3 ± 0.2 | 1.2 ± 0.1 | 1.8 ± 0.2 | 4.7 ± 0.9 | 2.8 ± 1.0 | 1.4 ± 0.1 | 2.0 ± 0.6 | 1.5 ± 0.1 | 1–3 | Minor enrichment |
C | 2.0 ± 0.7 | 3.4 ± 1.2 | 3.4 ± 1.0 | 1.9 ± 1.1 | 3.2 ± 1.4 | 8.4 ± 4.8 | 2.5 ± 1.0 | 2.6 ± 1.2 | 2.7 ± 1.2 | 2.5 ± 1.0 | 3–5 | moderate enrichment |
D | 2.4 ± 0.7 | 4.8 ± 2.7 | 4.3 ± 1.8 | 2.1 ± 1.2 | 3.4 ± 1.7 | 5.5 ± 1.8 | 2.8 ± 1.2 | 2.8 ± 1.4 | 2.9 ± 1.3 | 2.6 ± 1.2 | 5–10 | Moderately severe enrichment |
E | 2.1 ± 1.3 | 4.2 ± 2.1 | 4.3 ± 2.0 | 2.5 ± 1.2 | 4.4 ± 1.8 | 5.9 ± 3.3 | 3.0 ± 1.2 | 3.7 ± 1.6 | 3.8 ± 1.5 | 3.4 ± 1.2 | 10–25 | Severe enrichment |