| Parameter | Proficiency testing item M178A | Uncertainty | Proficiency testing item M178B | Uncertainty | Unit |
| Aluminium | 12.36 | 0.18 | 20.4 | 0.2 | µg/L |
| Arsenic | 1.075 | 0.015 | 1.592 | 0.016 | µg/L |
| Lead | 4.23 | 0.03 | 2.55 | 0.02 | µg/L |
| Cadmium | 0.993 | 0.011 | 1.916 | 0.014 | µg/L |
| Chromium | 4.58 | 0.03 | 1.233 | 0.013 | µg/L |
| Iron | 45.5 | 0.2 | 15.16 | 0.15 | µg/L |
| Copper | 3.44 | 0.03 | 5.28 | 0.04 | µg/L |
| Manganese | 21.94 | 0.13 | 15.10 | 0.11 | µg/L |
| Nickel | 3.46 | 0.03 | 9.06 | 0.06 | µg/L |
| Mercury | 1.800 | 0.018 | 1.004 | 0.016 | µg/L |
| Selenium | 1.20 | 0.02 | 1.95 | 0.02 | µg/L |
| Uranium | 4.98 | 0.03 | 2.391 | 0.018 | µg/L |
| Zinc | 56 | 1 | 17,2 | 0.6 | µg/L |