Page 198 - Materials Chemistry, Second Edition

182 4 Life Cycle Impact Assessment

further work is necessary, the impact assessment. A summary of different
definitions of the impact assessment can be found at. 4)
2. With a complete inventory, numerous data on mass flows, emissions, resource
consumption and energy demand are present, which are difficult to handle
and therefore, make aggregations desirable (see Section 3.7).
3. An inventory supplies more information than can be expected at first sight of
a listing of raw input and output data.
4. An ecological product comparison must not imply that, for example, a product
system A using less energy in its life cycle than product system B, but with
emissions of (environmental) toxic substances with a small mass flow but
substantial impact, performs better than product system B.
For these reasons there has been a continuing effort to develop a type of impact
related aggregation of the inventory results which goes beyond a cumulative energy
demand (CED) (see Section 3.2.2). Also the sum of solid wastes can be viewed
as an aggregation and as sum parameter at inventory level. It may be used as a
measure for the material throughput. Besides, this value gives a reference to the
primarily technical field of waste disposal, but this issue with its negative side
effects is traditionally regarded as an environmental problem area. The CED and
sum of solid waste were typical aggregations during the time of the ‘proto-LCA’.
The best-known earliest proposal of an aggregated impact estimation is the
Swiss method ‘of critical volumes’ (c.V.), which is discussed in Section 4.2. Started
around 1992 it was increasingly replaced by the method of environmental problem
fields or impact categories, developed by CML (Centrum voor Milieukunde Leiden),
Leiden (see Section 4.4). Environmental problem fields or impact categories are,
5)
for example, ‘acidification’ or ‘climate change’.
The standardisation of the LCA in the ISO 14040 series of standards corre-
sponds by structure and content to a large extent to the ideas developed by CML,
6)
although only with a general definition of impact assessment and no concrete
recommendations for impact categories:
Life cycle impact assessment LCIA:
Phase of life cycle assessment aimed at understanding and evaluating the magni-
tude and significance of the potential environmental impacts for a product system
throughout the life cycle of the product
In ISO 14044, the formulation potential environmental impacts emphasises that
theLCIAis not to be confused with an environmental risk assessment; in this case
substance-immanent properties would have to be correlated with the concentration
of these substances at the site of impact. 7)

4) Owens (1998).
5) Gabathuler (1998).
6) ISO (2006a, Section 3.4).
7) Such a risk assessment is, for example, requested by the European chemicals law REACH, EC
(2006).