| Metalic trace elements | Localities | ||
| Loumbila | Ouahigouya | Codex regulation limit (ppm) | |
| Cd total (ppm) | 0.11 ± 0.00 | 0.22 ± 0.28 | 0.05 |
| Pb total (ppm) | 1.27 ± 0.06 | 1.15 ± 0.27 | 0.1 |
| As total (ppm) | 0.19 ± 0.14 | 0.20 ± 0.02 | 0.01 |
| Hg total (ppm) | | |
|