Table 9.
Results of heavy metal pollution level and potential ecological risk in sewage sludge (bold indicates the highest levels).
| Index | Cd | Cr | Cu | Ni | Pb | Zn | Hg | |
|---|---|---|---|---|---|---|---|---|
| S1 | Igeo | 2.7 (M-HC) | −1.3 | 2.3 (M-HC) | 0.0 | 1.4 (MC) | 3.8 (HC) | 3.5 (HC) |
| ER | 293.6 (HR) | 1.2 | 35.7 | 7.4 | 19.3 | 21.0 | 664.8 (VHR) | |
| ICF | 2.6 (MC) | 1.2 (MC) | 9.2 (VHC) | 1.3 (MC) | 0.3 | 16.8 (VHC) | - | |
| RACm | 32.0 (HR) | 0.0 | 4.0 | 29.0 (MR) | 0.0 | 64.6 (VHR) | - | |
| ERF | 0.5 (MR) | 0.0 | 0.0 | 0.4 | 0.0 | 1.8 (HR) | - | |
| S2 | Igeo | 2.1 (M-HC) | −2.0 | 2.0 (MC) | −0.1 | 1.0 | 3.4 (HC) | 1.5 (MC) |
| ER | 189.0 (HR) | 0.7 | 30.1 | 6.9 | 15.2 | 16.0 | 172.4 (HR) | |
| ICF | 0.0 | 2.1 (MC) | 24.7 (VHC) | 1.1 (MC) | 0.9 | 63.0 (VHC) | - | |
| RACm | 51.0 (VHR) | 1.7 | 7.4 | 32.4 (HR) | 2.7 | 70.4 (VHR) | - | |
| ERF | 1.0 (MR) | 0.0 | 0.1 | 0.5 (MR) | 0.0 | 2.4 (HR) | - | |
| S3 | Igeo | 2.9 (M-HC) | −1.4 | 2.4 (M-HC) | 0.2 | 1.5 (MC) | 4.0 (HC) | 3.0 (M-HC) |
| ER | 91.4 (CR) | 109.5 (CR) | 691.4 (VHR) | 310.2 (HR) | 688.5 (VHR) | 1641.0 (VHR) | 29.1 | |
| ICF | 2.1 (MC) | 1.5 (MC) | 12.9 (VHC) | 1.3 (MC) | 0.1 | 18.1 (VHC) | - | |
| RACm | 35.5 (HR) | 0.0 | 1.5 | 30.9 (HR) | 0.0 | 61.4 (VHR) | - | |
| ERF | 0.5 (MR) | 0.0 | 0.0 | 0.4 | 0.0 | 1.6 (HR) | - | |
| S4 | Igeo | 2.9 (M-HC) | −1.2 | 2.5 (M-HC) | 0.2 | 1.6 (MC) | 3.9 (HC) | 2.3 (M-HC) |
| ER | 337.4 (VHR) | 1.3 | 41.3 (MR) | 8.7 | 22.0 | 22.9 | 301.0 (HR) | |
| ICF | 1.6 (MC) | 1.2 (MC) | 12.7 (VHC) | 1.2 (MC) | 0.1 | 16.0 (VHC) | - | |
| RACm | 25.0 (MR) | 0.0 | 1.2 | 27.0 (MR) | 1.2 | 55.8 (VHR) | - | |
| ERF | 0.3 | 0.0 | 0.0 | 0.4 | 0.0 | 1.3 (HR) | - | |
| S5 | Igeo | 2.5 (M-HC) | −1.4 | 2.2 (M-HC) | 0.1 | 1.4 (MC) | 3.8 (HC) | 3.5 (HC) |
| ER | 251.4 (HR) | 1.1 | 34.0 | 7.9 | 19.3 | 20.7 | 684.4 (VHR) | |
| ICF | 3.1 (CC) | 1.5 (MC) | 17.4 (VHC) | 1.3 (MC) | 0.2 | 28.6 (VHC) | - | |
| RACm | 37.7 (HR) | 2.0 | 3.8 | 40.8 (HR) | 0.0 | 68.7 (VHR) | - | |
| ERF | 0.6 (MR) | 0.0 | 0.0 | 0.7 (MR) | 0.0 | 2.2 (HR) | - | |
| S6 | Igeo | 3.3 (HC) | −1.1 | 2.9 (M-HC) | 0.8 | 2.0 (MC) | 4.2 (HC) | 3.5 (HC) |
| ER | 431.5 (VHR) | 1.4 | 54.6 (MR) | 13.3 | 29.6 | 27.1 | 692.7 (VHR) | |
| ICF | 1.8 (MC) | 1.0 | 12.8 (VHC) | 1.1 (MC) | 0.1 | 14.4 (VHC) | - | |
| RACm | 25.3 (MR) | 0.0 | 0.5 | 34.8 (HR) | 0.0 | 55.9 (VHR) | - | |
| ERF | 0.3 | 0.0 | 0.0 | 0.5 (MR) | 0.0 | 1.3 (HR) | - | |
| S7 | Igeo | 3.3 (HC) | −1.1 | 2.9 (M-HC) | 0.8 | 2.0 (MC) | 4.2 (HC) | 3.4 (HC) |
| ER | 435.7 (VHR) | 1.4 | 56.1 (MR) | 12.9 | 29.4 | 27.2 | 627.2 (VHR) | |
| ICF | 2.2 (MC) | 1.2 (MC) | 13.9 (VHC) | 1.2 (MC) | 0.2 | 16.7 (VHC) | - | |
| RACm | 23.4 (MR) | 2.4 | 1.4 | 35.9 (HR) | 0.0 | 55.0 (VHR) | - | |
| ERF | 0.3 | 0.0 | 0.0 | 0.6 (MR) | 0.0 | 1.2 (HR) | - |