Nitrogen and phosphorus balances for fresh surface water in the Netherlands, 1986-2001
Emissions of nitrogen and phosphorus fell considerably between 1986 and 2001. The accumulation of these substances in the environment does not reflect this fall since it is, to a significant extent, determined by precipitation and river flows.
| Inflow1) | ||||||
| 1986 | 1990 | 1995 | 1999 | 2000 | 2001 | |
| million kg N | ||||||
| Total | 714 | 533 | 570 | 487 | 432 | 473 |
| Transboundary rivers | 540 | 362 | 425 | 349 | 312 | 354 |
| Discharges | ||||||
| - industry | 23 | 18 | 7 | 7 | 6 | 6 |
| - households | 36 | 36 | 30 | 24 | 23 | 23 |
| - agriculture and horticulture2) | 10 | 9 | 6 | 6 | 6 | 5 |
| Agricultural land3) | 86 | 86 | 86 | 86 | 70 | 70 |
| Other land | 4 | 4 | 4 | 4 | 4 | 4 |
| Deposition4) | 15 | 18 | 12 | 11 | 11 | 11 |
| million kg P | ||||||
| Total | 78 | 47 | 36 | 35 | 26 | 20 |
| Transboundary rivers | 46 | 20 | 22 | 23 | 17 | 12 |
| Discharges | ||||||
| - industry | 15 | 16 | 4 | 4 | 2 | 1 |
| - households | 11 | 4 | 3 | 2 | 2 | 2 |
| - agriculture and horticulture2) | 1 | 1 | 0 | 0 | 0 | 0 |
| Agricultural land3) | 5 | 5 | 5 | 5 | 4 | 4 |
| Other land | 1 | 1 | 1 | 1 | 1 | 1 |
| Deposition | 0 | 0 | 0 | 0 | 0 | 0 |
| Source: CBS (). | CBS/EDC/Sep03/0194 | |||||
| 1) Excludes discharges to the sea. 2) Direct emissions from fertiliser to ditches and discharges into drainage water from horticulture under glass. 3) Using new calculation method from 2000 onwards. In time, the years in the history will be recalculated using a comparable method. As a result, the trend shift shown at present will be eliminated. 4) Based on a freshwater surface area of 0.39 million hectares and average wet and dry deposition of 29 kg N/ha in 2001. | ||||||
| Outflow1) | ||||||
| 1986 | 1990 | 1995 | 1999 | 2000 | 2001 | |
| million kg N | ||||||
| Total | 714 | 533 | 570 | 487 | 432 | 473 |
| To the sea | 550 | 343 | 551 | 330 | 339 | 360 |
| Dredging sludge | 7 | 6 | 3 | 3 | 3 | 3 |
| Accumulation | 157 | 184 | 16 | 154 | 90 | 110 |
| million kg P | ||||||
| Total | 78 | 47 | 36 | 35 | 26 | 20 |
| To the sea | 42 | 23 | 32 | 18 | 18 | 13 |
| Dredging sludge | 6 | 5 | 3 | 3 | 3 | 2 |
| Accumulation | 30 | 19 | 1 | 14 | 5 | 5 |
| Source: CBS (). | CBS/EDC/Sep03/0194 | |||||
| 1) Excludes discharges to the sea. 2) Direct emissions from fertiliser to ditches and discharges into drainage water from horticulture under glass. 3) Using new calculation method from 2000 onwards. In time, the years in the history will be recalculated using a comparable method. As a result, the trend shift shown at present will be eliminated. 4) Based on a freshwater surface area of 0.39 million hectares and average wet and dry deposition of 29 kg N/ha in 2001. | ||||||
Developments in discharges to surface water
Discharges to surface water fell considerably between 1986 and 2001: discharges of nitrogen by approximately 50% and discharges of phosphorus by approximately 85%. The reduction from industry was approximately 75% for nitrogen and 90% for phosphorus due to intensive clean-up operations and modified production processes. The fall for households of 35% for nitrogen and 80% for phosphorus is mainly the result of alterations to urban wastewater treatment plants for nitrogen and phosphate removal and the introduction of phosphate-free detergents.
Note on accumulation
Changes in emissions are not always reflected in the accumulation figure. The inflow and outflow via rivers is largely determined by the weather. The low accumulation level in 1995, for example, is partly a result of heavy rain and the resulting higher flow rate in 1995.
Policy objective
In order to comply with the European Nitrate Directive, run-off of nutrients from agriculture must be reduced. Stricter legislation, including the Mineral Accounting System (MINAS), is intended to bring about a further reduction in the surpluses from agriculture.
- Discussion of MINAS and the European Nitrate Directive
