Miljøprojekt, 1029 – Analyser for pesticider i punktkilder

Analyser for pesticider i punktkilder

Summary

Background and objectives

Pesticides are being found more and more often in groundwater, abstraction wells and upper soil layers. The number of locations where pesticides are found, as well as the number of pesticides in individual samples, are increasing in step with the increasing number of studies and with the development of the methods of investigation and analysis.

The use of pesticides differs depending on the sectors involved. Regional authorities in Denmark have requested a more systematic survey of the pesticides used in different sectors, how they were used, and which pesticides should be examined.

Cooperating with the Danish EPA, the Soil Contamination Knowledge Centre of the regional authorities has initiated a project aiming at preparing prioritised lists of the pesticides that are being and have been used in the different sectors. Supported by information on local conditions, the lists can contribute to enhancing the assessment of analyses required in connection with point sources of contamination of soil and groundwater.

The project follows up on earlier studies, where pesticides were mapped with a view to application within:

Nurseries
Market gardening
Fruit growing
Forestry
Equipment yards and landscape gardeners
Machine pools, and
Seed dressing

Method

During the mapping carried out previously, a total of 635 applications of 250 substances in seven sectors were recorded. Based on these data, this project selects a number of substances in each sector, in which the risk of point-source contamination is assessed to be most serious. The selection of substances in each sector is based on the following criteria:

High application frequency and large quantities applied (frequent/large application increases the risk of point-source contamination).
Type of substance presenting a risk of point-source contamination (only substances handled several times at the same location present a risk of point-source contamination).
Previous findings (positive detection in Denmark and abroad is considered to indicate that a substance presents a risk of contamination).

All selected substances are described in terms of analysis methods or lack of reliable method for determination of the substance involved. Assessment of the options available for analysis of the many relevant pesticides was based on a number of analysis methods published in international scientific literature. For a number of substances that are not covered by the published methods the assessment is, however, based on expected analogy (for instance structural analogy) with substances covered by the methods.

Results

The results are presented in tables of the substances considered relevant for analysis in connection with investigation of point sources within each of the seven sectors (see Chapter 6).

Lists were also prepared of the physical-chemical properties of the pesticides, and of their hazards. The lists are intended for use in connection with setting up the final investigation programme for locations with known geological and soil conditions, and for risk assessments.