Page 296 - Materials Chemistry, Second Edition

280 4 Life Cycle Impact Assessment

Examples for abiotic factors are radiation (intensity and spectral composition),
temperature, pH value, currents (air and water), chemical composition of water,
soil and air and the cycles and rhythms of these factors. Ecosystems are open
systems implying an energy transfer with the surrounding environment exists and
they are interconnected by material transfer over the atmosphere or the water as
well as by an exchange of organic materials with energetic content.
Ecotoxicity examines harmful changes of structures and functions of ecosystems
caused by an anthropogenic entry of substances. Because of the complexity of
interactions in ecosystems the examined system is usually strongly simplified in
practice and an issue under investigation is selected within defined boundary
conditions: often only a small number of selected test organisms (fish, daphnia,
algae or earthworms, etc.) are examined for selected effects and under defined
laboratory conditions. An examined effect in the simplest case is acute toxicity of a
substance on the test organism, measured by the concentration of the substance in
the water whereby 50% of the test organisms die (LC ). Tests for the determination
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of chronic toxicity, reproduction or carcinogenic effect are more elaborate. In some
cases model ecosystems (so-called mesocosms) are also examined in the laboratory
or in a field study; frequently small ponds are used. From these results it is difficult,
if not impossible, to draw conclusions on the damage of the impacting structures
on larger ecosystems. 327)
4.5.3.3.2 Chemicals and Environment The handling of chemicals as substances
in the sense of the chemical laws by humans requires a knowledge of whether
the regarded substance is a poison, originally for reasons of worker and consumer
protection (see impact category human toxicity). A frequently used measure for the
acutetoxicityofasubstance is LD experimentally determined on animals. Ecotox-
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icology is the application of this confined terminology on poisons to environmental
issues, as perceived by admission authorities: usually the LC -value is determined
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in water, for example, for the water flea (daphnia magna), a small water crustacean
suitable as a test organism. It is presumptuous to extrapolate from single species
tests with a few organisms to ecotoxicity – even if safety factors are considered – for
the following reasons:

1. Ecological systems can react more sensitively than individuals of a species
Chemicals can intervene with the function of ecosystems with no toxic effects
at all on cells, such as by a disturbance of the chemical communication
system. 328) Stratospheric ozone depletion which is separately addressed in the
impact assessment is another example. A combination of ecotoxicological test
systems that would have been successful in identifying this impact can hardly
be imagined. Freons (used e.g. as refrigerants) are practically non-toxic and
therefore, not ecotoxic either, strictly speaking. LC - values cannot determine
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either a direct eco-toxic impact like the damage of the endocrine system of

327) (Kl¨ opffer (1989, 1993, 1994c).
328) Stumm (1977) and Klaschka (2008, 2009).