Report from the Sub-comittee on the environment and health

• Controlling weeds in farmyard areas
• Storage and disposal of packaging
and chemical waste
• Emptying residual spray liquid onto
topsoil or gravel-surfaced areas
IPU = Isoproturon.
2,500 m 3 water and that
washing of gloves can pollute
100 m 3 water.
• The area load is generally high
and <strong>the</strong>re is a big risk of
pollution of groundwater and
well water.
• Just a few leaching ml can
pollute large quantities of water.
• (see table 4.22)
A number of factors mean that <strong>the</strong> areas mentioned can be particularly
critical. Pesticides <strong>from</strong> buried packaging and <strong>from</strong> filling and washing
sites can affect <strong>the</strong> surroundings in a very concentrated form. They can
also impede microbial activity, bringing degradation more or less to a
standstill. Washing and filling sites are used regularly for many years.
That means a big area load, compared with use of <strong>the</strong> pesticide for field
spraying. In addition, washing and filling sites are often unsuitably sited
on areas surfaced with gravel and stone but without any organic topsoil.
This significantly increases <strong>the</strong> risk of pollution. When topsoil, with its
content of humus, is removed, so are <strong>the</strong> microorganisms on which
biological degradation of spilled pesticides mainly depends. And <strong>the</strong> big
potential for sorption and retention is removed as well. That results in a
relatively high rate of transport of water and pesticides. For <strong>the</strong> same
reason, <strong>the</strong> use of herbicides in farmyard areas and lanes puts well water
and groundwater at risk.
Ano<strong>the</strong>r reason why pollution <strong>from</strong> filling and washing sites is
particularly problematical is that <strong>the</strong> pesticides are led to <strong>the</strong> ground with
a relatively large quantity of water, which increases <strong>the</strong> risk of leaching.
The yards may also be connected with drains, so <strong>the</strong> pesticides can be led
to watercourses or lakes. In addition, spraying equipment is often washed
and filled close to wells, so leaching can occur directly in <strong>the</strong>m unless
special measures are taken to prevent it.
Table 4.22
Examples of pesticides in water used to wash spraying equipment. As <strong>the</strong> examples
show, emptying even <strong>the</strong> diluted washing water out onto <strong>the</strong> ground can present a
risk. The spray-liquid tank should be washed out several times with even small
amounts of water. As <strong>the</strong> examples show, diluting 10 litres twice to 100 litres gives
100 times dilution. If <strong>the</strong> 10 litres are diluted to 50 litres in four goes, <strong>the</strong> water
consumption will be only 160 litres, but <strong>the</strong> dilution will now be 625 times greater
(Jensen et al. 1998).
Assumptions: The pesticide is mixed with 150 l water per ha. After spraying, <strong>the</strong>
tank contains remaining spray liquid – normally 5-50 l. If 10 l is left and is
diluted up to 100 l with clean water twice, a dilution of 100 times will be
achieved.
Active ingredient in
spraying and
washing water:
The limit of 0.1
µg/L can be
exceeded in <strong>the</strong>
following
quantities of
water:
55