Page 247 - Materials Chemistry, Second Edition

10 Life Cycle Impact Assessment 233

Global scale
air
Continental scale
air

urban air

Coastal
agricultural marine
soil natural soil freshwater water

agricultural
natural soil freshwater ocean
soil

Fig. 10.18 The USEtox fate model [taken from Rosenbaum et al. (2008)]

mutations, behavioural changes, or changes in biomass or photosynthesis. These are
the effects that may be observed during standardised laboratory-based ecotoxicity
tests, and the results are specific for each combination of substance and species.
Toxic effects are further distinguished into acute, sub-chronic and chronic toxicity
(including further sub-groups like sub-acute, etc.). Acute toxicity describes an
adverse effect after a short period of exposure, relative to the lifetime of the animal
(e.g. <7 days for vertebrates, invertebrates or plants and <4 days for algae). Chronic
toxicity is based on exposure over a prolonged period of time covering at least one
life cycle or one sensitive period (e.g. 32 days for vertebrates, 21 days for
invertebrates, 7 days for plants and 4 days for algae).
When relating to freshwater ecosystems, the question arises what exactly we
mean by that. In LCIA, a freshwater ecosystem is typically seen as consisting of at
least three trophic levels:
1. Primary producers, converting sunlight into biomass via photosynthesis (i.e.
phytoplankton, algae)
2. Primary consumers, living off primary producers (i.e. zooplankton, inverte-
brates, planktivorous fish)
3. Secondary consumers at the upper end of the aquatic food chain (i.e. piscivorous
fish)