Macroparameters in shallow groundwater in the Netherlands, 1985-2003
| Substance, by type of soil and land use | 1985 | 1990 | 1995 | 2000 | 2003 |
| Percentage of measurements over desired quality standard | |||||
| Aluminium (drinking water standard 0.2 mg/l) | |||||
| Sand_agriculture | * | 21 | 19 | 17 | 19 |
| Sand_nature | * | 33 | 33 | 37 | 30 |
| Fluvial clay_agriculture | * | 4 | 0 | 0 | 0 |
| Marine clay_agriculture | * | 5 | 7 | 9 | 9 |
| Peat_agriculture | * | 4 | 4 | 4 | 4 |
| Sulphate (desired quality standard 150 mg/l) | |||||
| Sand_agriculture | 8 | 8 | 9 | 5 | 4 |
| Sand_nature | 0 | 0 | 2 | 2 | 2 |
| Fluvial clay_agriculture | 7 | 7 | 7 | 17 | 14 |
| Marine clay_agriculture | 23 | 26 | 23 | 19 | 21 |
| Peat_agriculture | 4 | 4 | 4 | 4 | 4 |
| Potassium (drinking water standard 12 mg/l) | |||||
| Sand_agriculture | 20 | 20 | 22 | 23 | 24 |
| Sand_nature | 2 | 5 | 2 | 2 | 2 |
| Fluvial clay_agriculture | 10 | 7 | 7 | 7 | 3 |
| Marine clay_agriculture | 49 | 51 | 51 | 51 | 51 |
| Peat_agriculture | 27 | 27 | 27 | 31 | 31 |
| Nitrate-N (drinking water standard 11.3 mg/l) | |||||
| Sand_agriculture | 17 | 23 | 22 | 20 | 20 |
| Sand_nature | 0 | 2 | 7 | 7 | 2 |
| Fluvial clay_agriculture | 3 | 3 | 3 | 3 | 7 |
| Marine clay_agriculture | 0 | 0 | 0 | 0 | 0 |
| Peat_agriculture | 0 | 0 | 0 | 0 | 0 |
| Ammonia-N (desired quality standards: sandy areas 2 mg/l, clay + peat 10 mg/l) | |||||
| Sand_agriculture | 22 | 23 | 22 | 20 | 21 |
| Sand_nature | 5 | 5 | 8 | 2 | 2 |
| Fluvial clay_agriculture | 3 | 3 | 7 | 7 | 10 |
| Marine clay_agriculture | 44 | 44 | 44 | 42 | 42 |
| Peat_agriculture | 31 | 31 | 31 | 31 | 31 |
| Total P (desired quality standards: sandy areas 0.4 mg/l, clay + peat 3 mg/l) | |||||
| Sand_agriculture | 5 | 6 | 10 | 9 | 6 |
| Sand_nature | 0 | 0 | 0 | 0 | 0 |
| Fluvial clay_agriculture | 0 | 0 | 0 | 0 | 0 |
| Marine clay_agriculture | 9 | 16 | 16 | 19 | 16 |
| Peat_agriculture | 8 | 12 | 12 | 15 | 15 |
| Source: RIVM Landelijk meetnet grondwaterkwaliteit. | RIVM/EDC/Aug04 | ||||
Developments relating to other substances in shallow groundwater
As a result of eutrophication, the nitrate levels in shallow groundwater (5-15 m depth) under agricultural land in the sandy areas are often higher than the desired quality standard. In clay and peatland areas, there are sometimes exceedances of the desired quality standard, with the main cause being high natural concentrations of the substance in question. There were no definite changes in the period in question.
Policy
The World Health Organization (WHO), followed by the EU (in its Drinking Water Directive of 1980) and the Dutch government (in the Water Supply Act), set the Maximum Allowable Concentration (MAC) for nitrate in water for human consumption at 50 mg/l. The EU Nitrate Directive assumes that all water which is a possible source of drinking water must meet the MAC standard. Consequently, the groundwater in the Netherlands must also meet this MAC standard. The directive includes a limit of 170 kg/ha for the amount of nitrogen applied in manure. The Netherlands implemented the Nitrate Directive in the mineral accounting system (MINAS) and a system of manure transfer contracts. However, in October 2003, the European Court of Justice rejected the current Dutch fertiliser policy. MINAS will therefore be replaced from 2006 onwards by a system of use standards for both chemical fertilisers and manure.
Relevance
All the listed substances constitute a threat to the quality of the drinking water.
Technical note
The data come from the Trendmeetnet verzuring Grondwaterkwaliteit (Acidification Trend Measurement Network for Groundwater Quality).
References
- Reijnders, H.F.R., G. van Drecht et al. (1998). The Quality of the Groundwater in the Netherlands. J. of Hydrology, 207: pp 179-188.
- National Groundwater Quality Monitoring Network
- Groundwater quality in your area
