| Element | Concentration normally found in surface water | WHO guidelines |
| Sb | <4 μg/l | 0.02 mg/l |
| As | - | 0.01 mg/l |
| Cd | <1 µg/l | 0.003 mg/l |
| Cr+3, Cr+6 | <2 µg/l | Chrome total: 0.05 mg/l |
| Cu+2 | - | 2 mg/l |
| Pb | - | 0.01 mg/l |
| Hg | <0.5 µg/l | 0.01 mg/l |
| Ni | <0.02 µg/l | 0.07 mg/l |
| Zn | - | 3 mg/l |