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(147) Ecotoxicological impacts in Life Cycle Assessment. Huijbregts, Mark1,2, van de Meent, Dik3, Goedkoop, Mark4, Spriensma, Renilde4, 1 2 3 4 ABSTRACT- Dealing with ecotoxicological impacts is a common part of the environmental life cycle assessment of products (LCA). Until recently, characterisation factors, used for aggregating ecotoxicological impacts in LCA, were based on the hazard index (PEC/PNEC-ratio). The problem with this approach is, however, that the hazard index may be a poor basis for the aggregation of pollutants. The same marginal change in the hazard index of two or more substances may still reflect an unequal change in ecotoxicological impacts, because the shape and actual working point on the species sensitivity distribution curves are not considered in the hazard index calculations. An index of toxic pressure based on the Potentially Affected Fraction of species (PAF), as derived from Species Sensitivity Distributions, may allow a more proper aggregation of toxic impacts due to exposure to multiple substances. Two ways for implementation of the PAF-concept in LCA will be explained. The first method combines non-interactive concentration and response addition rules of calculus, while the second method solely starts from non-interactive concentration addition rules of calculus. Outcomes of both methods are compared for 33 substances in fresh water aquatic ecosystems, showing differences up to 2.2 orders of magnitude. In addition, the prerequisites of a conversion of ecotoxicological impacts to ecosystem damage were explored. Although calculations are technically possible, substantial research is still needed to underpin the validity of both PAF-approaches to assess multi-substance ecosystem impacts and guarantee well-validated conversion rules for ecotoxicological impacts to ecosystem damage. Key words: PAF, LCA, mixture, ecotoxicity |
