Report from the Sub-comittee on the environment and health

Spraying scenarios
closer to <strong>the</strong> aquatic environment than 2 metres. When pesticides are
sprayed in mixtures, <strong>the</strong> biggest distance requirements for <strong>the</strong> individual
pesticides in <strong>the</strong> mixture are used for <strong>the</strong> entire mixture. The model does
not include transport of pesticides via rainwater or long-distance
atmospheric transport. It is also assumed that <strong>the</strong> wind comes <strong>from</strong> only
one direction. Lastly, it is assumed that <strong>the</strong> pond does not receive water
<strong>from</strong> drains or <strong>from</strong> groundwater. If <strong>the</strong> treatment frequency index is 0.1,
that corresponds to <strong>the</strong> pond being exposed once every 10 years. The data
used for <strong>the</strong> simulation are data <strong>from</strong> toxicity tests in <strong>the</strong> laboratory.
Unlike <strong>the</strong> o<strong>the</strong>r scenarios, <strong>the</strong> scenarios for <strong>the</strong> aquatic environment are
based on <strong>the</strong> plant protection product statistics for 1997. Models have
been constructed for <strong>the</strong> main crops – cereals (winter and spring cereals),
rape (winter and spring), potatoes, beets, peas and maize. In <strong>the</strong> model,
<strong>the</strong> consumption of pesticides (primarily glyphosate) on "areas treated
post-harvest" is linked to <strong>the</strong> cultivation of cereals (winter cereals). The
dosage and time of application of <strong>the</strong> various pesticides have been taken
<strong>from</strong> "Guide to Plant Protection" (Danish Institute of Agricultural
Sciences 1998). The effect on <strong>the</strong> aquatic environment <strong>from</strong> grass-seed
and vegetable production, market gardens and forestry, has not been
included in <strong>the</strong> study. Growth regulators are not included because <strong>the</strong>
treatment frequency index in 1997 was only 0.05.
The following special scenarios for treatment frequency index and crop
distribution have been analysed (Møhlenberg, Gustavson 1999):
• 2.34-scenario. Corresponding to present production but with a
treatment frequency index of 2.34 and a crop composition based on
1997 data.
• 1.17-scenario. A 50% reduction in <strong>the</strong> treatment frequency index for
all crops compared with <strong>the</strong> 2.34 scenario, with unchanged crop
composition.
• 0.59-scenario. Compared with <strong>the</strong> 2.34 scenario, this scenario is
characterised by a radical restructuring of cultivated areas to comprise
only cereal fields and set-aside, relatively more spring cereal than
winter cereal, a 50% reduction of <strong>the</strong> treatment frequency index in
winter cereal and only one tenth <strong>the</strong> treatment frequency index in
spring cereal, making <strong>the</strong> average treatment frequency index 0.59.
• 0.26-scenario. Compared with <strong>the</strong> 2.34 scenario, this scenario is
characterised by a switch <strong>from</strong> winter cereal to spring cereal,
increased set-aside and preservation of acreages used for potatoes,
rape, beets, peas and maize. The average treatment frequency index is
0.26.
As a general rule, <strong>the</strong> spraying scenarios are built up with <strong>the</strong> most
widely used pesticides. Pesticides with a low treatment frequency index
(< 5%) are generally not included in <strong>the</strong> model if homologously acting
pesticides are used on a large area. Specifically acting pesticides against,
for example, wild oat-grass, are included, however, even though <strong>the</strong>
treatment frequency index is low. For dressing agents and herbicides that
are incorporated after application, <strong>the</strong> risk of transport to <strong>the</strong> aquatic
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