Water quality in the Rhine and Maas Rivers, 1980-2002
The quality of the water in the Rhine and Maas has remained more or less constant in recent years. Only the concentration of phosphate has increased slightly.
| Parameter | Location | Annual average values | ||||||
| 1980 | 1990 | 1995 | 1999 | 2000 | 2001 | 2002 | ||
| Rhine | mg O2/l | |||||||
| Oxygen | Lobith | 8.0 | 9.8 | 10.0 | . | 10.0 | 10.1 | 10.1 |
| Maassluis | 8.1 | 9.1 | 9.3 | . | 10.3 | 10.1 | 9.0 | |
| mg Cl/l | ||||||||
| Chloride | Lobith | 168 | 187 | 120 | 95 | 92 | 86 | 84 |
| Maassluis | 632 | 1 362 | 1 106 | 832 | 822 | 681 | 640 | |
| mg N/l | ||||||||
| Nitrogen1) | Lobith | 1.9 | 1.3 | 0.9 | <0.8 | <0.5 | <0.54 | <0.8 |
| Maassluis | 1.7 | 1.0 | 1.0 | <0.7 | <0.6 | <0.7 | 0.7 | |
| mg P/l | ||||||||
| Phosphate | Lobith | 0.66 | 0.30 | 0.20 | 0.18 | 0.18 | 0.11 | 0.22 |
| Maassluis | 0.65 | 0.36 | 0.34 | 0.21 | 0.19 | 0.11 | 0.21 | |
| m3/sec | ||||||||
| Flow rate2) | Lobith | 2 572 | 1 856 | 2 795 | 2 811 | 2 521 | 2 849 | 2 974 |
| Maas | mg O2/l | |||||||
| Oxygen | Eijsden | 9.7 | 8.2 | 8.6 | . | 8.9 | 8.9 | 8.8 |
| Keizersveer | 10 | 9.6 | 9.5 | . | 9.2 | 9.8 | 9.5 | |
| mg Cl/l | ||||||||
| Chloride | Eijsden | 41 | 65 | 37 | 39 | 32 | 34 | 39 |
| Keizersveer | 50 | 74 | 45 | 40 | 36 | 34 | 42 | |
| mg N/l | ||||||||
| Nitrogen1) | Eijsden | 1.3 | 1.5 | <1.4 | 1.1 | 1.0 | 0.81 | 1.2 |
| Keizersveer | 1.4 | 1.1 | 0.9 | 0.7 | 0.6 | 0.7 | <0.9 | |
| mg P/l | ||||||||
| Phosphate | Eijsden | 0.58 | 0.51 | 0.32 | 0.36 | 0.30 | 0.22 | 0.32 |
| Keizersveer | 0.5 | 0.31 | 0.23 | 0.22 | 0.22 | 0.19 | 0.19 | |
| m3/sec | ||||||||
| Flow rate2) | Eijsden | 221 | 191 | 341 | 313 | 310 | 375 | 346 |
| Source: RIZA. | CBS/EDC/Oct03/0249 | |||||||
| 1) Kjeldahl nitrogen, the fraction of hydrolysable organic nitrogen and ammonium. 2) Flow rate data not available for Maassluis and Keizersveer . | ||||||||
Developments
There has been a continuing improvement in water quality in both the Rhine and Maas rivers for the substances listed.
Policy
The policy is focused on reducing emissions of chloride, nitrogen and phosphate so that the desired quality standard - the concentration that indicates a negligible effect on the environment - will no longer be exceeded in 2010. International treaties have been entered into with, among others, Germany, Belgium and France.
Relevance
High concentrations of chloride, nitrogen and phosphorus affect the ecosystem of the large rivers. Furthermore, high concentrations can lead to treatment problems when surface water is used as the source for drinking water. Because water from the Rhine is channelled into lower-lying areas during dry periods, the quality of the Rhine also influences the quality of the regional waters in the west of the country.
