Multimedia fate models, exposure factors and toxicological measures are commonly used to provide an indication of the relative concern of a unit mass of a chemical in an LCA inventory in the context of toxicological stress to ecosystems.  The methods for this characterisation step proposed by Guinee et al. (1996), Hertwich et al. (1998), Huijbregts (1999), and others, are sometimes considered to be "midpoint" approaches.  Goedkoop and Spriensma  (2000) recently adopted an alternative, which was distinguished as a "damage" or "endpoint" approach.  It is therefore timely to identify and consider the significance of the key fundamental differences between these "midpoint" and "endpoint" characterisation methods for ecotoxicological impacts.  As the fate and exposure models used are common to both approaches, at least in principle, this presentation will address key differences in the toxicological component.  For example, whether it is preferable to use a "marginal" or a "linear" measure and complications associated with the consideration of background conditions.

References:

1. Guinee J., Heijungs R., van Oers L., van der Meent D., Vermeire T. and Rikken M., LCA Impact Assessment of Toxic Releases, Ministerie van Volkshuisvesting, Ruimtelijke Ordening en Milieubeheer (1996)
2. Hertwich E.G., Pease W.S., and McKone T.E., Evaluating Toxic Impact Assessment Methods: What Works Best?, Env. Sci. and Tech., 32, 138A-145A (1998)
3. Huijbregts M.A.J., Priority Assessment of Toxic Substances in the Frame of LCA: Development and Application of the Multi-Media Fate, Exposure and Effect model USES-LCA, University of Amsterdam, The Netherlands (1999)
4. Goedkoop M. and Spriensma R. (PRe Consultants), The Eco-Indicator 99: A damage orientated method for life cycle impact assessment, VROM, Ministry of Housing, Spatial Planning and the Environment, Netherlands (2000)