Concentrations en nitrates des eaux de surface
 | 0.00- 1.99 mg/l |
 | 2.00 - 9.99 mg/l |
 | 10.00 - 24.99 mg/l |
 | 25.00 - 39.99 mg/l |
 | 40.00 - 49.99 mg/l |
 | >50.00 mg/l |
| 0.00- 1.99 mg/l |
| 2.00 - 9.99 mg/l |
| 10.00 - 24.99 mg/l |
| 25.00 - 39.99 mg/l |
| 40.00 - 49.99 mg/l |
| >50.00 mg/l |