Miljøprojekt, 1159 – Strategier overfor pesticidtruslen mod grundvandet fra punktkilder – forprojekt

Strategier overfor pesticidtruslen mod grundvandet fra punktkilder – forprojekt

Summary and conclusions

Pesticides constitute a serious problem for the groundwater resource and the water works in Denmark. Many sources for herbicide contamination exist, and till now there has only been limited work concerning the huge number of potential points sources and sources from smaller areas. It could be sites for washing of sprayers or farmyards, which locally may cause significant groundwater pollution with many different herbicides. Today it is unknown to which extent these local problems constitute a problem for the groundwater resource on catchment scale.

Currently, the knowledge level for site investigations and remedial actions is insufficient in order to prioritize actions towards pesticide point sources. This generates a large uncertainty with respect to evaluation of the economic aspects of the environmental consequences of pesticide point sources within a catchment area for a water works or for the ground water resource in general.

I this project the overall aspects of pesticide point sources are described, and 5 interrelated sub projects are proposed. The 5 sub projects describe a coherent project plan, which can lead to a significant improvement of knowledge within the area.

The first proposal for a sub project is a pesticide database, which is supposed to support investigations of pesticide-contaminated sites. Today, a database gathering information especially relevant for the counties staff within this area is not available. A reliable and user-friendly database is expected to be a significant technical move for authorities and consultants.

The proposal for the subsequent sub projects will be developed in a specific catchment area for a water works. The report suggests four possible catchment areas, which are selected from a list of criteria. It is important that the areas are well described with respect to geology and hydrogeology, and that pesticides are found in significant amounts.

In the specific catchment area the following should be performed:

- Risk assessment and prioritizing of sources of pesticide and other sources of contaminants affecting groundwater and water works

- Mapping, investigations of contaminant sites and risk assessment of specific pesticide point sources

- Development of remediation technologies for pesticide point sources

- Evaluation of the environmental economical consequences of actions in a catchment area

A prerequisite for an overall success of the project is a strong integration between sub projects and technical leadership throughout the project period.