Report from the Sub-comittee on the environment and health

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The distribution of finds of pesticides in <strong>the</strong> water companies’ wells is
very reminiscent of <strong>the</strong> distribution in <strong>the</strong> groundwater monitoring
system.
• The water companies have found BAM, (2,6-dichlorobenzamide), in
approx. 30% of 1,656 tested wells, with <strong>the</strong> limit value exceeded in
around 11%.
• In <strong>the</strong> groundwater monitoring areas it is not possible to relate finds of
pesticides in aquifers to specific land use in fields and o<strong>the</strong>r areas.
• A report on pesticides detected in groundwater near <strong>the</strong> surface in rural
groundwater monitoring areas shows an equal distribution of
agricultural and non-agricultural pesticides. Most of <strong>the</strong> substances
found are now banned or regulated.
• In <strong>the</strong> pesticide finds in groundwater, <strong>the</strong> limit value of 0.1
microgramme per litre for drinking water is exceeded in up to 13% of
<strong>the</strong> samples. The metabolite BAM <strong>from</strong> <strong>the</strong> universal herbicide
dichlobenil has been detected in 30% of <strong>the</strong> water companies’ wells, but
a wide range of substances used by farmers for treating crops are also
present in a relatively large number of wells. Larger amounts of
pesticides were detected in drain water and soil water than in
groundwater, and this may reflect concentrations that may similarly
later move towards <strong>the</strong> groundwater, during which <strong>the</strong>y may undergo
degradation and possible formation of metabolites. In both watercourses
and ponds, a number of pesticides have been detected in higher
concentrations than <strong>the</strong> concentrations that have effected aquatic
organisms in <strong>the</strong> laboratory.
4.2 Occurrence of pesticides in watercourses
In <strong>the</strong> following, <strong>the</strong> occurrence of pesticides in watercourses is described.
The effects of <strong>the</strong>ir occurrence are described in section 5.3. These data
have also been used in calibrating <strong>the</strong> models for calculating <strong>the</strong>
consequences of a partial phase-out of pesticides.
Pesticides can reach watercourses through:
• spray drift
• spraying too close to watercourses
• deposition <strong>from</strong> <strong>the</strong> air through long-distance atmospheric transport
• leaching <strong>from</strong> treated fields and transport to watercourses via drainage
pipes or groundwater
• surface run-off
• pollution <strong>from</strong> point sources, e.g. machine-washing sites.
The sources with <strong>the</strong> biggest implications for watercourses, quantitatively,
are run-off <strong>from</strong> land treated with pesticides and leaching with transport in
drain water. Direct spraying and leaching <strong>from</strong> washing sites are unlawful
pollution events that imply a considerable risk of harmful effects in
watercourses. Surface run-off <strong>from</strong> sloping fields can lead both watersoluble
substances and substances that bind to particles of soil out into a