How spatialize impact evaluation? New attempts for eutrophication
Comment spatialiser l'évaluation des impacts ? Nouvelles tentatives pour l'eutrophisation
Résumé
Context: The eutrophication phenomenon is a well-known local environmental issue in aquatic systems around the world. Some spatialized characterization methods in LCA are promising but do not allow spatial differentiation at refine scale. Aim: After an overview of literature, this paper proposes two new methodologies, the ex-ante and ex-post approaches, to calculate spatialized characterization factors (CF) for eutrophication. Both methods consider the surrounding environment sensitivity, however their usage differs depending on the practitioner needs. Method: The principle of both approaches is to consider a sensitivity factor for eutrophication calculation to mitigate the CML-IA CFs for respectively freshwater and marine eutrophication at local and regional scale. Results: The ex-ante approach aims to calculate accurate CFs at local scale based on models to assess the fate of phosphorous and nitrogen and on the determination of local sensitivity due to morphological and hydrological characteristics of river-basin and coastal areas. The ex-post approach is based on the threshold exceeded frequency of chlorophyll-a and pheopigments current concentrations. Conclusion: The ex-ante approach appears relevant to spatialize eutrophication for a more precise study at local scale while the ex-post approach appears relevant for regional studies.