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Livscyklusvurdering (LCA) er anvendt til at sammenligne miljøeffekterne ved forskellige alternativer til at rense op på to forskellige TCE-forurenede grunde. De sammenlignede afværgealternativer for Lokalitet 1 er (i) in situ stimuleret reduktiv deklorering, (ii) in situ termisk desorption og (iii) bortgravning, ekstern rensning og deponering. Disse tre alternativer er sammenlignet med basisscenariet, hvor der ikke renses aktivt op, men blot moniteres. For Lokalitet 2 er følgende afværgemetoder sammenlignet: (i) in situ stimuleret reduktiv deklorering og (ii) in situ kemisk oxidation. Disse alternativer er igen sammenlignet med et basisscenarium, hvor der ikke renses op, men blot moniteres. Desuden er der inkluderet et scenarium, hvor der i stedet for at blive renset op i kilden behandles med aktivt kul på vandværket. Resultaterne viser overordnet set, at biologisk oprensning med in situ reduktiv deklorering er den teknik, der har de laveste miljøpåvirkninger. Til gengæld har denne teknik en lang tidsramme og kan give toksiske påvirkninger af grundvandet grundet udsivning af vinylchlorid, som er et mellemprodukt i den reduktive deklorering.

Dans le but de rendre possible la transition vers une économie verte, les organisations ont besoin d’approches visant à traduire ce concept dans leur modèle d’affaires, afin de prendre des décisions éclairées et d’éviter le déplacement de problèmes. L’approche de gestion du cycle de vie consiste à l’adoption d’une vision holistique sur les produits et activités d’une organisation, basée sur l’ensemble du cycle de vie, soit de l’extraction des ressources à la gestion en fin de vie, selon les principes du développement durable. Afin d’accroitre l’adoption de cette approche dans l’industrie, il est impératif de pouvoir démontrer ses avantages, ainsi que les bénéfices que peut en retirer une entreprise. L’objectif principal de cet essai est de démontrer comment la mise en oeuvre d’une approche de gestion du cycle permet de créer de la valeur en entreprise et permet l’atteinte d’un avantage compétitif. Pour ce faire, une revue de littérature des différents outils de gestion du cycle de vie et en particulier sur les développements méthodologiques actuels et futurs de l’analyse du cycle de vie a été réalisée. Puis, une analyse des différents champs d’action en entreprise permet de mettre en lumière le potentiel de bénéfices tangibles et intangibles pour l’ensemble des parties prenantes. Ces bénéfices sont ensuite traduits en leviers de création de valeur soit : diagnostic du portefeuille de projets et de produits, innovation et développement de nouveaux produits, acquisition de parts de marché et de nouveaux consommateurs, commercialisation et ventes vertes, chaîne de valeur durable, opérations durables, gestion règlementaire, gestion de la réputation et gestion opérationnelle. Ainsi, il s’avère que la mise en oeuvre d’une approche de gestion du cycle de vie peut contribuer à l’atteinte d’un avantage compétitif en favorisant des occasions de croissance, en améliorant le retour sur investissement et par la réduction de divers risques. Les propos avancés sont supportés par d

The USEtox model was developed in a scientific consensus process involving comparison of and harmonization between existing environmental multimedia fate models. For freshwater ecosystem toxicity, it covers the entire impact pathway, i.e., transforming a chemical emission into potential impacts based on quantitative modeling of fate, exposure, and ecotoxicity effects. Taken together, these are represented as chemical-specific characterization factors (CFs). Through analysis of freshwater CFs for approximately 2500 organic chemicals, with special focus on a subset of chemicals with characteristic properties, this work provides understanding of the basis for calculations of CFs in USEtox. In addition, it offers insight into the chemical properties and critical mechanisms covering the continuum from chemical emission to freshwater ecosystem toxicity. For an emission directly to water, the effect factor, which is obtained from laboratory measurements of substance toxicity to different phyla, strongly controls freshwater ecotoxicity, with a range of up to 10 orders of magnitude. Chemical-specific differences in multimedia transfer influence the CF for freshwater emissions by less than two orders of magnitude. However, for an emission to air or soil, differences in chemical properties may decrease the CF by up to 10 orders of magnitude, as a result of intermedia transfer and degradation. This result brings new clarity to the relative contributions of fate and freshwater ecotoxicity to the overall characterization factor.

Background, aim, and scope : Task Force 3 of the UNEP/SETAC Life Cycle Initiative has been working towards developing scientifically sound methods for quantifying impacts of substances released into the environment. The Clearwater Consensus follows from the Lausanne (Jolliet et al. Int J Life Cycle Assess 11:209–212, 2006) and Apeldoorn (Apeldoorn Int J Life Cycle Assess 9(5):334, 2004) statements by recommending an approach to and identifying further research for quantifying comparative toxicity potentials (CTPs) for ecotoxicological impacts to freshwater receptors from nonferrous metals. The Clearwater Consensus describes stages and considerations for calculating CTPs that address inconsistencies in assumptions and approaches for organic substances and nonferrous metals by focusing on quantifying the bioavailable fraction of a substance. Methods : A group of specialists in Life Cycle Assessment, Life Cycle Impact Assessment, metal chemistry, and ecotoxicology met to review advances in research on which to base a consensus on recommended methods to calculate CTPs for metals. Conclusions and recommendations : Consensus was reached on introducing a bioavailability factor (BF) into calculating CTPs where the BF quantifies the fraction of total dissolved chemical that is truly dissolved, assuming that the latter is equivalent to the bioavailable fraction. This approach necessitates calculating the effects factor, based on a HC50EC50, according to the bioavailable fraction of chemical. The Consensus recommended deriving the BF using a geochemical model, specifically WHAM VI. Consensus was also reached on the need to incorporate into fate calculations the speciation, size fractions, and dissolution rates of metal complexes for the fate factor calculation. Consideration was given to the characteristics of the evaluative environment defined by the multimedia model, which is necessary because of the dependence of metal bioavailability on water chemistry.

Under the UNEP-SETAC Life Cycle Initiative there is an aim to develop an internationally backed recommended practice of life cycle impact assessment addressing methodological issues like choice of characterization model and characterization factors. In this context, an international comparison was performed of characterization models for toxic impacts from chemicals in life cycle assessment. Six commonly used characterization models were compared and in a sequence of workshops. Crucial fate, exposure and effect aspects were identified for which the models differed in their treatment. The models were harmonized in an iterative way removing those identified differences which were unintentional or unnecessary and thereby reducing the inter-model variation. A parsimonious (as simple as possible but as complex as needed) and transparent consensus model, USEtox™, was created containing only the most influential model elements. The USEtox™ model produces substance characterization factors, which fall within the range of the results from the participating models, i.e. the new characterization factors do not deviate more from the existing characterization factors than these deviate from each other. The USEtox™ model has been used to calculate characterization factors for several thousand substances and is currently under review with the intention that it shall form the basis of the recommendations from the UNEP-SETAC Life Cycle Initiative regarding characterization of toxic impacts in Life Cycle Assessment. The results are also applicable to comparative chemical assessments outside of LCA.

Life cycle impact assessment (LCIA) characterizes emissions for the life-cycle assessment (LCA) of a product by translating these emissions into their potential impacts on human health, ecosystems, global climate and other resources. This process requires substance-specific characterization factors (CFs) that represent the relative potential of specific chemical emissions to impact human disease burden and ecosystem health. Within the Life Cycle Initiative, a joint initiative of the United Nations Environment Program (UNEP) and of the Society of Environmental Toxicology and Chemistry (SETAC), a consensus model called USEtox was established to develop internationally harmonized CFs. In 2005 the LCI initiated an international comparison of six models used to make CF calculations. In this paper we describe this model-comparison process and its results_in particular the consensus model. The comparison focused on model differences both in terms of results and model structure. In three workshops, the model comparison participants identified crucial fate, exposure and effect issues for which the models differed. This process identified important sensitivities, differences in assumptions, and model structures that could be harmonized among the different models. Through this process, we were able to reduce inter-model variation. This process also led to the development of a consensus model that contained only the most influential model elements. The consensus model provided a parsimonious and transparent tool for making human health and ecosystem CF estimates. The consensus model has now been used to calculate CFs for several thousand substances and is intended to form the basis of the recommendations from UNEP-SETAC‘s Life Cycle Initiative regarding characterization of toxic impacts in Life Cycle Assessment.

Over the last two years, the developers of seven toxicity characterization models collaborated to carry out a comprehensive model comparison as part of the UNEP/SETAC Life Cycle Initiative. The models in this evaluation included CalTOX, IMPACT 2002, USES-LCA, BETR, EDIP, WATSON, and EcoSense. This paper summarizes and draws lessons from this model evaluation process. The main objectives of this effort were to 1) identify specific sources of differences in model results, 2) define common and indispensable model components, and 3) use the selected models to build a “scientific consensus” model, called USEtox, to serve as a repository for recommended practice. USEtox is a parsimonious and transparent tool that currently provides human-health characterisation factors (CFs) for some 1000 chemicals and aquatic ecotoxicity CFs for more than 2000 substances. The accuracy of these factors relative to other models remains within 1-3 orders of magnitude compared to 12 orders of magnitude variation among the chemicals. The main task of model development is complete, but the following future activities are foreseen for the upcoming second phase of the UNEP/SETAC Life Cycle Initiative: 1) increase of substance coverage and quality assurance of substance data; 2) accommodation of metals; 3) inclusion of terrestrial and marine ecotoxicity; 4) incorporation of indoor emissions; 5) including parameter uncertainty in the uncertainty estimates on the CFs; 6) publication of model documentation 7) development and distribution of a user-friendly version of USEtox; 8) industry/stakeholder workshops on comparative assessment of chemicals and training courses in USEtox. The promising scientific results now need to be transferred into daily LCA practice, which is the main goal of these activities, aiming at a broad acceptance and consideration of the toxicity impact categories.

Life cycle assessment studies (LCA) according to ISO 14040 and ISO 14044 and using generic data (i.e. without regard for geographic variability in the life cycle inventory or life cycle impact assessment ) are well adapted to evaluate environmental impacts from a global perspective. For impact categories that are not global in nature such as acidification, eutrophication, or toxicity, the use of generic data can lead to results that do not reflect the impacts accordingly. Clearly, the need for spatial differentiation depends on the scope and boundaries of the study. However, when assessing LCIs from different regions, or when geographical conditions of the emission location are known, regionalization might increase the discriminating power of LCIA. Future research should be focused on developing guidelines identifying when spatial differentiation is relevant, what type of differentiation is needed, and on generating and linking compatible LCI and LCIA that are both geographically specific to continents (for political reasons this is more accepted) and situation dependent to better reflect local variations.