Page 223 - Materials Chemistry, Second Edition

4.4 Method of Impact Categories (Environmental Problem Fields) 207

Category
indicator of
Inventory impact
results category “Category
Inventory are assigned endpoints”
results Assignment: to impact “Midpoint
inventory categories indicator”
results and
impact
categories
Quantitative
modelling
of category indicator
Classification
Characterisation

Figure 4.3 Impact category, classification/characterisation and assignment of end points
(schematic): following the characterisation framework according to ISO CD 14042.3. 69)

4.4.3.1 Hierarchy of Impacts
The stressor concept and the impact hierarchy were introduced during the SETAC
Workshop in Sandestin, Florida. 72) The term stressor is disputed and has not been
generally accepted. A stressor within the scope of an LCA was defined as a chemical
or physical factor from the inventory that can interact with the animate and
inanimate environment by diverse impacts at multiple system levels like single
organisms, species, communities and ecosystems (mostly but not always above a
single species effect threshold). As an overall expression for all types of influences
on the environment the word intervention is used in the literature. In the context of
literature on operational environmental management (also in ISO 14040/44) the
term environmental aspects is used to describe influences on the environment with
potential impacts. The basic idea behind these expressions will be discussed by the
following examples.
An interrelation of these impacts and end points differing for each category is
schematically illustrated in Figure 4.3. An indicator can be defined as ‘closer to the
inventory’ or ‘closer to individual endpoints’ (see also Figure 4.2).
Impacts can be arranged according to the SETAC Sandestin Workshop (Fava
et al., 1993, loc. cit.) within a hierarchy of primary, secondary and tertiary impacts
as illustrated by the following examples:

71) A corresponding scheme was adapted, though not by form, to the standard 14042:2000; see ISO
14044 (Figure 3).
72) Fava et al. (1993).