Report from the Sub-comittee on the environment and health

Biobeds
Municipal environmental
supervision
Fungi that form
mycotoxins
174
water tanks can be post-mounted on most sprayers without major
problems.
An alternative to filling and cleaning <strong>the</strong> sprayer in <strong>the</strong> field is <strong>the</strong>
establishment of a biobed (Helweg, Hansen 1997). A biobed is a
biological filter or mini treatment plant for any pesticide that is spilled
during filling or washed off during washing of <strong>the</strong> spraying equipment.
The biobed material is characterised by high microbiological activity and
a good sorption for <strong>the</strong> pesticides. Tests going on at <strong>the</strong> Danish Institute
of Agricultural Sciences and <strong>the</strong> National Department of Plant
Production have shown that biobeds have a good ability to bind and
break down pesticides. The tests also show, however, that <strong>the</strong> biobed
should be closed at <strong>the</strong> bottom in order to ensure against leaching
through <strong>the</strong> bed. It must also be ensured that percolating water can be
collected at <strong>the</strong> bottom of <strong>the</strong> bed. There are at present no real guidelines
or recommendations on biobeds because <strong>the</strong>y cannot be given before
official authorisation of a prototype. Also lacking is official acceptance
of disposal of biobed material by spreading in <strong>the</strong> field. That is not
expected to be a problem. If more complicated methods of disposal were
required, farmers would probably lose interest in biobeds.
In 1998, DEPA directed Denmark’s local authorities to give higher
priority to checking <strong>the</strong> handling of pesticides when carrying out
environmental inspections at <strong>the</strong> individual farms. The main things to be
checked are whe<strong>the</strong>r <strong>the</strong> sprayer operator holds a spraying certificate,
whe<strong>the</strong>r washing and filling sites are properly arranged <strong>from</strong> an
environmental point of view and whe<strong>the</strong>r <strong>the</strong> products used are properly
and safely stored and disposed of.
9.8 Interaction between pesticides, including growth
regulators, and production of toxins
Some of <strong>the</strong> fungi that occur in plant production can produce so-called
mycotoxins, many of which are extremely toxic to humans and animals.
The following survey of this area is based on a report by Elmholt (1998).
Mycotoxins can be absorbed through <strong>the</strong> gastrointestinal tract, <strong>the</strong> mouth,
<strong>the</strong> lungs or <strong>the</strong> skin. At least 300 different mycotoxins have been
identified, but only about 20 of <strong>the</strong>m are today thought to be of
importance with respect to animal feed and human nutrition. Some
mycotoxins, e.g. tricho<strong>the</strong>cenes and ochratoxin A, are found in crops
produced in <strong>the</strong> EU, while o<strong>the</strong>rs, e.g. aflatoxin, occurs particularly in
crops imported <strong>from</strong> <strong>the</strong> tropics. The occurrence of <strong>the</strong>se mycotoxins is
thus unrelated to changes in <strong>the</strong> use of pesticides in Denmark. It is
estimated that 20% of <strong>the</strong> cereal crops used for fodder contain
measurable quantities of mycotoxins (Smith et al. 1994).
Different families of fungi can form toxins under Danish conditions. The
main ones are Penicillium and Fusarium (Elmholt 1998). Only a few
species within <strong>the</strong> families present a real risk. The Nordic Council of
Ministers (1998) carried out an analysis of <strong>the</strong> intake of mycotoxins in
<strong>the</strong> Nordic countries and a risk assessment of selected fusarium toxins.
There is also often some variation in <strong>the</strong> capacity to produce toxins
between strains within <strong>the</strong> same species. In <strong>the</strong> case of many of <strong>the</strong> fungi