Pesticides in the soil in the Netherlands
| Substance1) | β-HCH | γ-HCH2) | HCB | β-hepta-chlorine-epoxide2) | Aldrin2) | Endrin2) | Dieldrin3) | α-endosulphane2) | Total DDT |
| Year prohibited 4) | 1999 | 1999 | 1973 | 1978 | 1982 | 1988 | 1980 | 1990 | 1973 |
| Desired quality standards5) ?g/kg) | 9 | 0.05 | 2.5 | 0.0002 | 0.06 | 0.04 | 0.5 | 0.01 | 10 |
| Category | Percentage of measurements over desired quality standard | ||||||||
| Dairy holdings on sandy soil | 0 | 64 | 15 | 11 | 0 | 0 | 52 | 0 | 55 |
| Intensive livestock holdings | 66 | 60 | 16 | 55 | 4 | 4 | 38 | 1 | 35 |
| on sandy soil | |||||||||
| Forest/mulch | 15 | 100 | 0 | 90 | 0 | 0 | 100 | 0 | 10 |
| Forest on sandy soil | 10 | 20 | 5 | 15 | 0 | 0 | 60 | 0 | 5 |
| Arable crops on sandy soil | 1 | 96 | 90 | 16 | 1 | 28 | 100 | 0 | 81 |
| Dairy holdings on peat | 0 | 46 | 0 | 26 | 0 | 1 | 68 | 0 | 6 |
| Arable holdings on marine clay | 0 | 25 | 68 | 13 | 3 | 0 | 45 | 0 | 69 |
| Dairy holdings on | 0 | 66 | 10 | 0 | 0 | 1 | 6 | 0 | 43 |
| fluvial clay | |||||||||
| Dairy holdings on marine clay | 0 | 21 | 30 | 10 | 0 | 0 | 21 | 0 | 29 |
| Vegetable culture | 0 | 20 | 53 | 3 | 8 | 0 | 50 | 30 | 70 |
| Flower bulb culture | 0 | 46 | 100 | 29 | 36 | 0 | 100 | 0 | 17 |
| Source: Groot et al. (1998). | RIVM/EDC/Oct02 | ||||||||
| 1) Samples were also tested for the substances α-HCH, δ-HCH and heptachlor, but virtually none of these substances were found. 2) Desired quality standard is far below the detection limit, percentage of exceedances may be higher than indicated. 3) Desired quality standard is around the detection limit, percentage of exceedances may be higher than indicated. 4) The year in which the substance was prohibited in the Netherlands. 5) Desired quality standard is dependent on the organic matter content of a soil. The desired quality standard for a standard soil (10% organic matter) is shown. | |||||||||
Development
The levels of a number of now-prohibited persistent pesticides (pesticides that degrade slowly) exceed the desired quality standards in soil in much of the Netherlands. This is primarily the case for the drins, DDT, HCB, γ-HCH en β-heptachlorine epoxide.
The high levels are the legacy from when the use of these substances was still allowed. Although use of the agents is now prohibited, levels in soil fall only slowly because these substances are not easily degradable in soil. It is also possible, because many of these substances are still permitted elsewhere in Europe, that a number of them may still be reaching Dutch soil by atmospheric deposition. It is striking that the desired quality standards for pesticides are also exceeded on a wide scale in forests.
Policy
The policy objective for the long term is conformity with the desired quality standard everywhere. The persistent, slowly-degrading, agents are now prohibited and have been replaced by agents that are broken down more quickly.
Relevance
High levels of pesticides in the soil of rural areas can have a negative effect on soil ecosystems. Pesticides can also enter groundwater and surface water and they therefore constitute a threat to drinking water quality and surface-water ecosystems.
Persistent pesticides are substances that degrade very slowly in the environment and are often still present after decades. They are organic chlorine compounds such as drins (aldrin, dieldrin, endrin) and DDT.
