| Heavy metal | Site A | Site B |
| Cr | 3.7 | 2.5 |
| Mn | 1.3 | 1.1 |
| Cd | ND | ND |
| Ni | 0.6 | 0.4 |
| Cu | 1.4 | 0.8 |
| Zn | 1.0 | 0.7 |
| As | 9.2 | 6.8 |
| Pb | ND | 0.2 |