Page 222 - Materials Chemistry, Second Edition

206 4 Life Cycle Impact Assessment

undesirable trends on the basis of case studies was published by the European
Environmental Agency. 68) Most of these negative environmental trends could have
been avoided by an improved attention to the precautionary principle. Some false
alarms in science, for example, the aluminium/Alzheimer discussion in the late
69)
1980s , however, cannot be ignored.
The speed of development of new impacts is illustrated by the fact that in earlier
LCAs (around 1990) the greenhouse effect (or global warming, or climate change)
was not even listed. Since the inaugural, seemingly ‘immortal’ list of Leiden, at
least four impacts have emerged, which are strongly discussed today:

• hormone disrupters: Substances, which either imitate or displace natural hor-
mones (blocking at site of impact); this mechanism is part of ecotoxicity, possibly
also human toxicity, reproduction damaging impacts;
• possible harmful impacts of genetically modified organisms (GMOs) (micro-
organisms, crops) on the environment;
• invasive species (a subset of the neophytes and neozoa characterised by abundant
proliferation, superseding indigenous species and changing ecosystems);
• freshwater as a regionally scarce resource.

These issues have been discussed in scientific literature for the last 10–20 a; a
(sometime heated) public discussion has been started, but the topics are still
insufficiently represented in LCIA.
Above all it should be learned from these considerations that it makes no
sense to presume that today all impacts of human activity on complex systems
like ecosystems are known. The list of the impact categories must therefore be
amended or updated from time to time, furthermore the precautionary principle
should, by suitable indicators, be represented in LCA. LCIA will therefore remain
70)
a permanent ‘building site’.
4.4.3
Stressor-Effect Relationships and Indicators

The following discussion relates more to group B of the newer SETAC Europe list
(Table 4.4) than to scarcity of resources (group A). The problems are, however,
similar in both groups. In both groups the question is on how to coordinate between
the results of the inventory and the impact categories. Thereby two issues need to
be clarified at the beginning:

• hierarchy of impacts (which approach to be chosen for characterisation, which
indicator to be used for quantification) and
• potential versus actual impacts.

68) EEA (2001).
69) Krishnan et al. (1988).
70) Schmidt-Bleek (1993, 1994), Kl¨ opffer and Renner (1995) and Kl¨ opffer and Volkwein (1995).