Report from the Sub-comittee on the environment and health

Limit values
Authorisation of pesticides
Acute reference dose
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exposure must be determined, both for <strong>the</strong> users and for <strong>the</strong> consumers.
Users should be understood to mean spraying personnel, workers and
o<strong>the</strong>rs who are exposed to <strong>the</strong> product during and after application. The
consumers are exposed to <strong>the</strong> pesticides through food and drinking water
or, for example, via soil pollution.
Allocating limit values for content in food products is part of this
authorisation procedure. If a substance can be authorised for use, a
maximum limit value, MRL (Maximum Residue Limit), is fixed for <strong>the</strong>
maximum residual content of <strong>the</strong> pesticide or its degradation or
transformation products in food products.
The limit value in food products is based partly on a toxicological
assessment of <strong>the</strong> health risk in connection with intake of <strong>the</strong> pesticide in
question, with an Acceptable Daily Intake (ADI) being set and partly on
<strong>the</strong> residual concentrations of <strong>the</strong> pesticide found in vegetable food
products after use of Good Agricultural Practice (GAP). GAP means <strong>the</strong>
nationally authorised methods of use that are necessary under current
conditions for effective control of pests. To arrive at <strong>the</strong> maximum limit
value, <strong>the</strong> health aspect (ADI) is combined with <strong>the</strong> use of <strong>the</strong> pesticide
in question (GAP). This is done by combining ADI with <strong>the</strong> Theoretical
Maximum Daily Intake (TMDI), calculated by means of diet models and
assuming that all crops for which <strong>the</strong> pesticide may be used contain <strong>the</strong>
maximum permissible amount of <strong>the</strong> pesticide. TMDI must lie below
ADI for a limit value to be set. In Denmark, it is <strong>the</strong> Danish Veterinary &
Food Administration that sets <strong>the</strong> limit values for food products.
In connection with <strong>the</strong> authorisation procedure, not only <strong>the</strong> pesticide’s
physical/chemical properties and its stability and degradation in nature
must be tested, but also its toxic properties. There are internationally
agreed guidelines for performance of <strong>the</strong> toxicological tests that are
included in <strong>the</strong> risk assessment of pesticides. Both <strong>the</strong> active ingredient
and <strong>the</strong> product must thus be tested for acute effects, and <strong>the</strong> active
ingredient must be tested for chronic effects through repeated, long-term
exposure (carcinogenicity, mutagenicity and effects on reproduction,
including malformation of <strong>the</strong> offspring). In addition, tests are required
concerning <strong>the</strong> substance’s absorption, metabolism, accumulation and
elimination, toge<strong>the</strong>r with any effect on enzymes and o<strong>the</strong>r biochemical
parameters. In <strong>the</strong> toxicological testing of chemicals, account must be
taken of <strong>the</strong> substance’s purity, stability in <strong>the</strong> exposure set-up and
reproducibility in a possibly repeated test.
In <strong>the</strong> nature of things, most of <strong>the</strong> testing of <strong>the</strong> health effects of
pesticides is done on animals (usually mice and rats) ra<strong>the</strong>r than people.
There can be differences between test animals and humans with respect
to metabolism, and far higher doses are normally used in <strong>the</strong> animal tests
than <strong>the</strong> general population could be exposed to.
For certain pesticides, however, <strong>the</strong>re is only a ra<strong>the</strong>r narrow margin
between <strong>the</strong> doses that are acutely toxic and <strong>the</strong> doses that have longterm
effects. For such pesticides, an acute reference dose is set in
addition to <strong>the</strong> usual ADI as a protection against acute toxic effects.
Readers are also referred to section 8.3 on <strong>the</strong> precautionary principle.