Report from the Sub-comittee on the environment and health

Mechanical weed control
208
Behandlingshyppighed
Sandsynligheden for effekter på
krebsdyr i vandhuller i 4 scenarier
�������������������
0,26 10
�������������������
����������������������������
0,59
15
����������������������������
���������������������������������������������
1,17
25
���������������������������������������������
������������������������������������������������������������������������������������������������
2,34
55
������������������������������������������������������������������������������������������������
0 20 40 60
Sandsynlighed i %
Figure 10.11
The model-based probability of effects on crustaceans in typical Danish
ponds in 4 scenarios with different crop distribution and treatment
frequency index (Møhlenberg, Gustavson 1999).
(Figure texts:
Sandsynligheden for effekter på krebsdyr i vandhuller i 4 scenarier =
Probability of effects on crustaceans in ponds in 4 scenarios
Behandlingshyppighed = Treatment frequency index
Sandsynlighed i % = Probability in %)
10.4 Exposure of humans
10.4.1 Exposure of, and effects on, <strong>the</strong> sprayer operator
Many of <strong>the</strong> existing loads and effects <strong>from</strong> <strong>the</strong> working environment in
agriculture would be <strong>the</strong> same, whe<strong>the</strong>r pesticides were used or not. On
<strong>the</strong> o<strong>the</strong>r hand, <strong>the</strong> exposure to pesticides would decrease with
decreasing use of <strong>the</strong> substances. In field spraying, <strong>the</strong> risk of exposure in
one working day can be 1000 times greater than <strong>the</strong> daily intake via food
products. If protection aids are not used, this risk can be considerably
greater.
With <strong>the</strong> present equipment for mechanical weed control, <strong>the</strong> time spent
driving a tractor would presumably increase. Compared with spray
booms, which have a width of 12-36 metres (most of <strong>the</strong>m are 12-24
metres), such tools as weed harrowers with a width of 12 metres and
brush weeders, which only handle a few metres at a time, would mean
more time spent driving a tractor. However, for <strong>the</strong> biggest crop, cereals,
harrowing 2-3 times would often be sufficient. That corresponds to a
number of field runs close to <strong>the</strong> treatment frequency index for cereals in
conventional farming, particularly when spraying against insects and
fungi is included.