Report from the Sub-comittee on the environment and health

concentrations than <strong>the</strong> limit value of 0.1 microgramme per litre for
drinking water.
• Pesticide concentrations in watercourses are transported with <strong>the</strong>
current. The highest concentrations are probably rarely detected
because <strong>the</strong> water containing <strong>the</strong> pesticides passes <strong>the</strong> sampling site
within such a short space of time that <strong>the</strong>re is very little chance of
extracting a sample of <strong>the</strong> polluted water.
• Small, slow-flowing watercourses and small ponds are most exposed
to any pesticide load.
• The impact on <strong>the</strong> flora and fauna in watercourses is brief, but even a
short pulse of pesticides can have a major, acute effect on <strong>the</strong>
watercourses’ ecological conditions. If <strong>the</strong> possibilities of
recolonisation are poor, e.g. due to barriers or geographical location,
<strong>the</strong> effects can in some cases be observed for more than one year.
• The pesticide concentration in ponds and lakes will be longer-lasting
than <strong>the</strong> concentration in watercourses. It will not be possible to
evaluate <strong>the</strong> occurrence and effect of pesticide concentrations in lakes
until data are available <strong>from</strong> <strong>the</strong> monitoring programme in connection
with Aquatic Environment Plan II.
• In watercourses, insecticides have been detected in concentrations that
very probably affect <strong>the</strong> fauna, and <strong>the</strong>re are documented cases of
effects of herbicides on algae and o<strong>the</strong>r primary producers.
• There is no national registration of <strong>the</strong> effects on <strong>the</strong> aquatic flora and
fauna.
• The sub-committee recommends that more consistent and systematic
use than hi<strong>the</strong>rto be made of permanent spray-free zones and
protection borders, which, as buffer zones, would help to protect
watercourses, lakes and ponds.
5.4 The sub-committee’s conclusions and recommendations
concerning environmental impacts
The main impacts occur in connection with <strong>the</strong> application of pesticides,
with organisms being hit directly, and with indirect effects occurring as a
consequence of <strong>the</strong> effect on food chains. Here, plants play a key role as
<strong>the</strong> first link in <strong>the</strong> food chains. A Danish study has shown that <strong>the</strong>
number and frequency of plant species in field studies have halved in <strong>the</strong>
last 20-25 years. From an agricultural point of view, this has been a
desirable development, but it has adverse consequences for <strong>the</strong> natural
species. The main reason for <strong>the</strong> decline is <strong>the</strong> use of herbicides, but
changes in cultivation practice, including <strong>the</strong> use of fertilisers, have also
had a major effect.
During spraying, <strong>the</strong>re is spray drift to <strong>the</strong> surrounding areas. However,
hedgerows, dikes, dry stone walls and o<strong>the</strong>r small biotopes are of such
small width that <strong>the</strong>y should in practice be included in <strong>the</strong> area that is
affected by spray products. Spray drift can affect both terrestrial and
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