Report from the Sub-comittee on the environment and health

easons. A similar situation arose in <strong>the</strong> summer of 1998 in connection
with <strong>the</strong> discussion on <strong>the</strong> use of <strong>the</strong> herbicide glyphosate to combat
couch grass in cereal crops shortly before harvest.
3) Drinking water <strong>from</strong> water supply systems
Owing to human error, a serious pollution situation occurred in a
provincial town (Fåborg) in Denmark in <strong>the</strong> middle of <strong>the</strong> 1970s. The
error resulted in <strong>the</strong> insecticide Parathion (Bladan) being sucked into <strong>the</strong>
pipe network, contaminating large parts of <strong>the</strong> town’s public water
supply system. The unavoidable decision taken was naturally that <strong>the</strong>
system was to be closed down and to remain closed ‘until <strong>the</strong> plant and
pipe network were free of any measurable residue of Bladan’. In o<strong>the</strong>r
words, <strong>the</strong> precautionary principle was applied even though, in <strong>the</strong> case
in question, a higher residual content than <strong>the</strong> limit applying at that time
(given as 0.1 microgramme per litre) could have been accepted on <strong>the</strong>
basis of a toxicological, health assessment. As a pollution situation that
attracted great public attention, this case (toge<strong>the</strong>r with similar cases in
o<strong>the</strong>r countries in Europe), had both direct and long-lasting consequences
for many subsequent cases, leading to today’s requirement of no (i.e.
‘immeasurable’ or only negligible) pesticide residues in drinking
water/groundwater.
8.2.1 Approaches to <strong>the</strong> precautionary principle
The following two approaches to <strong>the</strong> precautionary principle can be
described:
1) An effect assessment/risk management approach
The effect assessment/risk management approach is based on extensive
knowledge of data and o<strong>the</strong>r technical and scientific information. Using
statistically or pragmatically fixed (un)certainty factors, one assesses <strong>the</strong>
hazard of individual substances and <strong>the</strong> risk associated with <strong>the</strong>ir use. In
that connection, dose-effect curves and lowest effect values are as far as
possible established. Tools in this connection include setting of limit
values, threshold values, pollution standards, etc., often supplemented by
emission requirements based on health and environment considerations
and, possibly, regulation of use. This approach is illustrated in figure 8.1
below.
Effekt
Økotoksikologisk
risikovurdering
Laveste effektniveau
for akvatiske dyr og planter
Humantoksikologisk
risikovurdering
A 0,1 µg/L B C
Koncentration i vand
Laveste effektniveau
for mennesker
Figure 8.1
The risk assessment approach with relationship between dose and effect
for humans and for aquatic organisms and plants. C = lowest effect level
for humans, B = toxicologically set zero effect level using a safety factor,
161