Page 202 - Materials Chemistry, Second Edition

186 4 Life Cycle Impact Assessment

Production
Use phase
A
End-of-life
B B
A
A
B

A B

CED c.V. air c.V.water ∑Solid waste

Figure 4.1 Schematic representation of two fictitious eco-profiles (two product systems
related to the functional unit): Cumulative energy demand (CED); c.V. air; c.V. water; Sum
of solid wastes (example of an early ‘impact assessment’).

thus but rarely being applied outside of Switzerland 12) (in parts by BASF’s 13) eco-
efficiency method). The most important reasons for this declining attitude despite
14)
operational advantages are:

1. Purely scientifically deduced limit values occur in the rarest cases; they contain
elements of feasibility, analytic detectability, cognitive boundaries of science, of
social or economic desirability, and so on. Even if some limits may be close to
scientifically acknowledged toxicologically deduced effect thresholds, for others
political objectives prevail. An evaluating element is particularly integrated into
impact assessment by limit values that are partly defined by political reasoning.
This results in a blend of impact assessment and valuation, for example,
included in the so-called ecopoint methods. 15) Within these a border line
between impact assessment in the strict sense and valuation (weighting) is no
longer perceptible.
2. The limits vary by country. If no limits are available, values are designed using
various auxiliary assumptions (see hydrocarbons/HC according to BUWAL in
Table 4.1). This arbitrariness in use of self-made ‘limits’ has played a key role
in discrediting the method.
3. For many substances, especially in case of impacts without effect threshold, no
legal limits exist or, if they do, they exist only in the form of technical indicative
values, as with carcinogenic working substances. The same is true for many

12) Kl¨ opffer (1994a) and Kl¨ opffer and Renner (1995).
13) Saling et al. (2002) and Landsiedel and Saling (2002).
14) German: ¨ Okoeffizienzmethode.
15) BUWAL (1998, 1990), Steen and Ryding (1992), Goedkoop (1995) and Goedkoop et al. (1998).