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6A - LCIA - Toxicity/RA (WEP/222) Integrating bioavailability of metals into Life-Cycle Impact Assessment of Terrestrial Ecotoxicity. Daoust, Catherine1, Jolliet, Olivier2, Payet, Jérôme2, Samson, Réjean1, 3, Deschênes, Louise1, 3, 1 NSERC Industrial Chair in Site Remediation and Management, Montreal, Quebec, Canada2 GECOS - Life Cycle Systems Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud3 CIRAIG - Interuniversity Reference Center for the Life Cycle Analysis, Interpretation and Management of Products, Processes and, Montreal, Quebec ABSTRACT- Assessment of terrestrial ecotoxicity in Life-Cycle Assessment uses multi-media fate and exposure models to evaluate which part of an emission would result in an intake of contaminant by living organisms. Most currently used multi-media models are CALTOX, EUSES, USES-LCA and recently, IMPACT 2002. These models are divided into three modules: the fate, which is the distribution of an emission through different media; the exposure, characterizing the fraction taken up by organisms; and the effect, which is the quantified toxicological response to this intake of toxic based on NOEC or EC50 laboratory data. Up to now, multi-media models have not include a soil bioavailable fraction for metals to be connected to the terrestrial ecosystem toxicological response. Through the example of copper, strength and weaknesses of current multi-media models for assessing ecotoxicity of metals are explored and the influence of exposure modelling on the final impact assessment is outlined. In this context, results of a set of experiment on copper bioavailability in ten different soils are presented. Soils spiked in laboratory are constituted to cover the variability of North American and European soils for three main soil characteristics: soil content of organic matter, soil content of clay and pH. On this basis, several experiments are made: 1) correlation between terrestrial ecotoxicity and soil characteristics are calculated via the measurement of several soil metal pools and toxicological response of two organisms which are directly in contact with the soil matrix: eisenia fetida (earthworm) and hordeum vulgare (barley); 2) wetting and drying cycles are performed to evaluate the way bioavailable fraction behave with time in a realistic aerobic-anaerobic cycle scheme. For all the experiments, chemical extractions are made in order to characterize the soluble fraction and the readily exchangeable fraction (1M MgCl2). The free ion and other soluble complexes are also analysed. Key words: metals, bioavailability, LCA, ecotoxicity |
