Page 215 - Materials Chemistry, Second Edition

4.3 Structure of Impact Assessment according to ISO 14040 and 14044 199

Table 4.3 Ranking of the impact categories according to UBA.

Impact category Ranking by the German Federal Environmental Agency
It is stressed that another advisory board may provide
another ranking.
Ecological endangering Distance-to-target

Eutrophication (aquatic) B C
Eutrophication (terrestrial) B B
Land use A A
Photochemical ozone formation D B
Scarceness of fossil energy sources C B
Stratospheric ozone depletion A D
Greenhouse effect A A
Acidification B B
Human toxity a
Ecotoxity a
a The toxicity categories are individually discussed.

The ranking of impact categories according to the criterion ‘distance-to-target’
is similar to the approach described for the criterion ‘ecological endangerment’:
An interdisciplinary team classes the impact categories on a five-stage scale
(A–E). A highest, E lowest (Table 4.3).
3. Specific Contribution Specific contributions are used as the third criterion for
the ranking of impact categories (see Section 4.3.3.1, Example 1). They are
categorised by five classes, where the highest specific contribution serves as
the base factor:
A: highest priority 80–100% of the maximum value to
E: lowest priority 0–20% of the maximum value.
4. Unification of Results For a final ranking of the impact categories the results
are integrated according to the three grouping criteria with a fixed even-
45)
weighted pattern to an ‘ecological priority’ : If, for example, one impact
category concerning all three grouping criteria is assigned to group of A
(highest priority), these single results are subsumed as of ‘very large ecological
priority’. This signifies that the environmental loads of the examined product
system concerning this impact category are regarded as highly relevant.
The above detailed presentation of the example of the grouping method
according to UBA serves to clarify the following:
• The ranking in the element ‘grouping’ in the context of the impact
assessment is not trivial.
• The ranking of the impact categories include value choices. This cannot
be avoided. Different committees can at different times present different
rankings.

45) Schmitz and Paulini (1999).