Metals and arsenic in shallow groundwater in the Netherlands, 1990-2003
| Substance, by type of soil and land use | 1990 | 1995 | 2000 | 2003 |
| Percentage of measurements over desired quality standard | ||||
| Cadmium (desired quality standard 0.0004 mg/l) | ||||
| Sand_agriculture | 14 | 17 | 15 | 15 |
| Sand_nature | 24 | 22 | 17 | 20 |
| Fluvial clay_agriculture | 43 | 0 | 0 | 0 |
| Marine clay_agriculture | 2 | 7 | 2 | 2 |
| Peat_agriculture | 0 | 0 | 0 | 0 |
| Zinc (desired quality standard 0.065 mg/l) | ||||
| Sand_agriculture | 10 | 10 | 11 | 12 |
| Sand_nature | 23 | 23 | 23 | 23 |
| Fluvial clay_agriculture | 4 | 4 | 0 | 0 |
| Marine clay_agriculture | 0 | 7 | 14 | 14 |
| Peat_agriculture | 4 | 4 | 4 | 4 |
| Nickel (desired quality standard 0.015 mg/l) | ||||
| Sand_agriculture | 14 | 18 | 14 | 12 |
| Sand_nature | 24 | 24 | 24 | 27 |
| Fluvial clay_agriculture | 0 | 0 | 0 | 0 |
| Marine clay_agriculture | 0 | 0 | 2 | 0 |
| Peat_agriculture | 0 | 0 | 0 | 0 |
| Copper (desired quality standard 0.015 mg/l) | ||||
| Sand_agriculture | 5 | 4 | 4 | 4 |
| Sand_nature | 5 | 5 | 7 | 7 |
| Fluvial clay_agriculture | 0 | 0 | 0 | 0 |
| Marine clay_agriculture | 0 | 0 | 0 | 0 |
| Peat_agriculture | 0 | 0 | 4 | 0 |
| Chromium (desired quality standard 0.001 mg/l) | ||||
| Sand_agriculture | * | 40 | 34 | 38 |
| Sand_nature | * | 42 | 44 | 51 |
| Fluvial clay_agriculture | * | 4 | 8 | 4 |
| Marine clay_agriculture | * | 35 | 56 | 49 |
| Peat_agriculture | * | 48 | 56 | 44 |
| Arsenic (desired quality standard 0.01 mg/l) | ||||
| Sand_agriculture | 4 | 4 | 2 | 4 |
| Sand_nature | 2 | 0 | 2 | 2 |
| Fluvial clay_agriculture | 15 | 22 | 18 | 18 |
| Marine clay_agriculture | 2 | 5 | 5 | 5 |
| Peat_agriculture | 0 | 0 | 0 | 0 |
| Lead (desired quality standard 0.015 mg/l) | ||||
| Sand_agriculture | 4 | 2 | * | * |
| Sand_nature | 2 | 0 | * | * |
| Fluvial clay_agriculture | 4 | 0 | * | * |
| Marine clay_agriculture | 0 | 2 | * | * |
| Peat_agriculture | 0 | 4 | * | * |
| Source: RIVM Landelijk meetnet grondwaterkwaliteit. | RIVM/EDC/Aug04 | |||
| * Not analysed | ||||
Development
Levels of heavy metals in the shallow groundwater (5 - 15 m deep) under a considerable proportion of the sandy areas exceed the desired quality standard. This is the result of atmospheric deposition, the use of fertilisers and acidification of the soil. Relatively low levels are found for copper and lead. No clear changes have been observed.
Policy
The policy objective for the long term is to conform with the desired quality standard everywhere. The atmospheric deposition of heavy metals has declined in recent decades as a result of, among other things, the clean-up of the zinc industry in the south of the Netherlands and the introduction of unleaded petrol. Levels of heavy metals have also fallen in cattle feed and chemical fertiliser.
Relevance
High levels of heavy metals in groundwater can have an adverse effect on the quality of drinking water.
