Report from the Sub-comittee on the environment and health

• Measuring uncertainty in <strong>the</strong> experimental procurement of biological,
chemical and physical-chemical data. This is characterised by <strong>the</strong> fact
that we can calculate both probability for effects and uncertainty for
concrete biological or physical systems.
• The uncertainty in <strong>the</strong> assessment in <strong>the</strong> fur<strong>the</strong>r interpretation of
performed tests, often by transformation on extrapolation of
laboratory (and epidemiological) observations and measurements for
use with o<strong>the</strong>r organisms (e.g. animals to humans) or pollution
situations (e.g. aquatic environment to soil or air). This is
characterised by <strong>the</strong> fact that we have some knowledge about <strong>the</strong>
systems we describe, but variation and probability of risk depend on
estimation via interpretation of knowledge <strong>from</strong> one system or one
situation to ano<strong>the</strong>r.
• Uncertainty of knowledge or direct ignorance with insufficient or no
understanding or knowledge of effects or mechanisms behind effects,
including naturally also a lack of possibility of predicting effects that
are insufficiently described or that have not previously been observed.
This is characterised by <strong>the</strong> fact that we do not know <strong>the</strong> system
and/or <strong>the</strong> effects we have to describe and that we have no basis for
predicting risk, let alone calculate <strong>the</strong> probability of effect.
• Uncertainty concerning use or o<strong>the</strong>r uncertainty is linked to
indeterminacy in commercial and societal development, marketing
and use of pesticides. This is characterised by <strong>the</strong> fact that we
normally do not fully know <strong>the</strong> systems in which pesticide use and
dissipation is taking place - and we know that we do not know <strong>the</strong>m.
These four areas of uncertainty are characterised by an increasing lack of
knowledge, which thus reduces <strong>the</strong> scientific basis for decisions and
correspondingly increases <strong>the</strong> need for administrative or politically based
decisions.
The memorandum “Discussion of caution and risk” (<strong>Sub</strong>-committee for
Environment and Health 1998) gives a detailed description of different
areas of uncertainty and variation.
8.2.2 Groundwater and drinking water as a case
In Ministry of Environment and Energy Order on Water Quality and
Supervision of Water Supply systems, No. 515 of 29 August 1998, <strong>the</strong>
following is stated in chapter 2, section 4, concerning <strong>the</strong> quality of water
<strong>from</strong> water supply systems:
The water <strong>from</strong> water supply systems that supply people with water for
household use must meet <strong>the</strong> limit values for content of substances in <strong>the</strong>
water given as <strong>the</strong> highest permissible values in Annex 1 to this Order.
However, efforts must be made to ensure that <strong>the</strong> values are lower than
or within <strong>the</strong> values given as guideline values in Annex 1.
In Annex 1 to <strong>the</strong> Order, <strong>the</strong> guideline limit value for pesticides and
related products is put at “u.d.”, i.e. under <strong>the</strong> detection limit for a
method that can measure one tenth of <strong>the</strong> highest permissible value,
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