Pesticides in brackish and marine surface water in the Netherlands, 1997-2001
The levels of pesticides in brackish and marine surface water are generally declining, but they still exceed the standard at most monitoring sites. In the Western Scheldt, the standard is exceeded for all pesticides with the exception of lindane.
| Atrazine | Metalo | Simazine | Terbutyl- | Diuron | Lindane | |
| chlor | azine | (c-HCH) | ||||
| ng/l | ||||||
| Standard | 29 | 2 | 1 | 1.9 | 4 | 9 |
| Central North Sea | ||||||
| 1997 | <5 | <1 | <5 | <1 | ||
| 1998 | <5 | <1 | <5 | <1 | ||
| 2000 | <5 | <1 | <5 | <1 | ||
| 2001 | <5 | <1 | <5 | <1 | 1 | |
| Ems/Dollard | ||||||
| 1997 | 9 | 16 | <5 | <1 | ||
| 1998 | 18 | 33 | <5 | 37 | ||
| 2000 | 10 | 6 | 5 | 9 | ||
| 2001 | 10 | 11 | <5 | 13 | 55 | 3 |
| Grevelingenmeer | ||||||
| 1997 | 11 | <1 | 6 | <1 | ||
| 1998 | 10 | <1 | <5 | <1 | ||
| 2000 | 13 | <1 | <5 | <1 | ||
| 2001 | 8 | <1 | 7 | <1 | 86 | 1 |
| Coastal zone | ||||||
| 1997 | 11 | 3 | <5 | 1 | ||
| 1998 | 16 | 3 | 9 | 4 | ||
| 2000 | 17 | 4 | 6 | 2 | ||
| 2001 | 12 | 1 | 2 | 2 | 22 | 1 |
| Eastern Wadden Sea | ||||||
| 1997 | 12 | 1 | <5 | <1 | ||
| 1998 | 11 | <1 | <5 | <1 | ||
| 2000 | 12 | <1 | <5 | 2 | ||
| 2001 | 8 | <1 | <5 | 4 | 18 | 1 |
| Eastern Scheldt | ||||||
| 1997 | 18 | 4 | 10 | 3 | ||
| 1998 | 19 | 5 | 12 | 3 | ||
| 2000 | 20 | 4 | 13 | 3 | ||
| 2001 | 14 | 4 | 10 | 3 | 52 | 1 |
| Veerse Meer | ||||||
| 1997 | 16 | 2 | 20 | <1 | ||
| 1998 | 20 | <1 | 27 | <1 | ||
| 2000 | 17 | <1 | 30 | 5 | ||
| 2001 | 14 | <1 | 21 | <1 | 491 | 1 |
| Voordelta | ||||||
| 1997 | 11 | 6 | 6 | 3 | ||
| 1998 | 11 | <1 | <5 | <1 | ||
| 2000 | 15 | 6 | 9 | 2 | ||
| 2001 | 11 | <1 | 5 | <1 | 22 | 1 |
| Western Wadden Sea | ||||||
| 1997 | 18 | 2 | 6 | 4 | ||
| 1998 | 24 | 2 | 13 | 5 | ||
| 2000 | 15 | 2 | 6 | 3 | ||
| 2001 | 14 | <1 | 7 | 3 | 20 | 1 |
| Western Scheldt | ||||||
| 1997 | 83 | 52 | 47 | 33 | ||
| 1998 | 78 | 34 | 51 | 26 | ||
| 2000 | 132 | 56 | 61 | 15 | ||
| 2001 | 75 | 32 | 39 | 11 | 310 | 4 |
| Southern North Sea | ||||||
| 1997 | <5 | <1 | <5 | <1 | ||
| 1998 | <5 | <1 | <5 | <1 | ||
| 2000 | <5 | <1 | <5 | <1 | ||
| 2001 | <5 | <1 | <5 | <1 | 4 | 0 |
| Source: RIKZ, monitorings programme Rijkswaterstaat. | RIVM/EDC/Oct03 | |||||
Concentrations of pesticides in brackish and marine waters declining
The levels of atrazine in the Western Scheldt fell in 2001 compared to the previous year but they still exceed the desired quality standard. The same applies to simazine and terbutylazine. All the substances for which a desired quality standard has been established exceed the desired quality standard at one or more sites, with the exception of lindane. In the Western Scheldt, the standard is exceeded for all substances with the exception of lindane.
Diuron was included in the monitoring programme for brackish waters for the first time in 2001. The levels measured exceed the standard by a long way at many sites. Diuron is a herbicide that is mainly used in the upkeep of public green spaces. Its use was banned in the Netherlands on 1 June 1999.
Policy relating to pesticides
The policy objective is to reduce the use of pesticides. Maximum allowable concentrations (MAC) and a desired quality standard have been adopted for these pesticides (V&W, 1999). The standard used for brackish waters is the desired quality standard.
Relevance
The MAC and desired quality standard have been adopted on ecotoxicological grounds. That means that, when the levels are exceeded, negative effects on organisms cannot be excluded.
