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Purpose: There is increasing interest in using fate and exposure models to spatially differentiate the impacts of chemical emissions. This work aims at exploring the operationalization in life cycle assessment (LCA) of spatially differentiated models for toxic emissions into freshwater. We analyse and compare the variability of fate and exposure factors at high resolution with aggregated factors at different levels of lower resolution.Methods: We developed a spatially resolved fate and exposure characterization model and factors for toxic emissions into freshwater with global coverage at 0.5° × 0.5° resolution, extending a global hydrological model to account for removal processes, namely chemical and biological degradation, sedimentation, and volatilization. We analysed the variation in fate and exposure factors for water ingestion, identifying the main factors of influence. We then developed archetypes for ecosystems and human fate and exposure. Using a case study of emissions of arsenic from red mud disposal as a waste from alumina production, we tested practical solutions to apply spatial characterization factors aggregated at different resolution in LCA, comparing archetype-based with region-based approaches.Results and discussion: World maps show up to 5 orders of magnitude variation for chemical fate in fresh water across all 0.5° × 0.5° grid cells and up to 15 orders of magnitude for human intake fractions. The freshwater residence time to the sea and the equivalent depth—over all downstream cells—were the most influential landscape parameters. They were used to define four freshwater landscape archetypes. These archetypes capture variation in fate well, better than country or continent-aggregated values, but are not able to reflect variation in intake fraction. The case study on arsenic from alumina production shows that the determination of industry-specific weighted average represents a pragmatic way to account for sector-specific location of emissions. The population-weighted approach is primarily applicable for emissions that are related to population density, such as household emissions.Conclusions: The developed global freshwater model demonstrates large spatial variations in fate and exposure. Archetypes for fate in fresh water provide substantial reductions in variability compared to country or continental averages, but are more difficult to apply to LCA than rural or urban archetypes for air emissions. The 0.5° × 0.5° grid model and the fate archetypes may also be used in the context of ecological scenarios to identify hotspots. In practice, population-weighted and sector-specific average characterization factors may represent the most operational way to account for specific distribution patterns of toxic emissions in LCA. [ABSTRACT FROM AUTHOR]

Purpose: Product systems use the same unit process models to represent distinct but similar activities. This notably applies to activities in cyclic dependency relationships (or "feedback loops") that are required an infinite number of times in a product system. The study aims to test the sensitivity of uncertainty results on the assumption made concerning these different instances of the same activities. The default assumption assumes homogeneous production, and the same parameter values are sampled for all instances (e.g., there is one truck). The alternative assumption is that every instance is distinct, and parameter values are independently sampled for different instances of unit processes (e.g., there are infinitely many trucks). Intuitively, sampling the same values for each instance of a unit process should result in more uncertain results.Methods: The results of uncertainty analyses carried out under either assumption are compared. To simulate models where each instance of a unit process is independent, we convert network models to acyclic LCI models (tree models). This is done three times: (1) for a very simple product system, to explain the methodology; (2) for a sample product system from the ecoinvent database, for illustrative purposes; and (3) for thousands of product systems from ecoinvent databases.Results and discussion: The uncertainty of network models is indeed greater than that of corresponding tree models. This is shown mathematically for the analytical approximation method to uncertainty propagation and is observed for Monte Carlo simulations with very large numbers of iterations. However, the magnitude of the difference in indicators of dispersion is, for the ecoinvent product systems, often less than a factor of 1.5. In few extreme cases, indicators of dispersion are different by a factor of 4. Monte Carlo simulations with smaller numbers of iterations sometimes give the opposite result.Conclusions: Given the small magnitude of the difference, we believe that breaking away from the default approach is generally not warranted. Indeed, (1) the alternative approach is not more robust, (2) the current default approach is conservative, and (3) there are more pressing challenges for the LCA community to meet. This being said, the study focused on ecoinvent, which should normally be used as a background database. The difference in dispersion between the two approaches may be important in some contexts, and calculating the uncertainty of tree models as a sensitivity analysis could be useful. [ABSTRACT FROM AUTHOR]

Purpose: Some LCA software tools use precalculated aggregated datasets because they make LCA calculations much quicker. However, these datasets pose problems for uncertainty analysis. Even when aggregated dataset parameters are expressed as probability distributions, each dataset is sampled independently. This paper explores why independent sampling is incorrect and proposes two techniques to account for dependence in uncertainty analysis. The first is based on an analytical approach, while the other uses precalculated results sampled dependently.Methods: The algorithm for generating arrays of dependently presampled aggregated inventories and their LCA scores is described. These arrays are used to calculate the correlation across all pairs of aggregated datasets in two ecoinvent LCI databases (2.2, 3.3 cutoff). The arrays are also used in the dependently presampled approach. The uncertainty of LCA results is calculated under different assumptions and using four different techniques and compared for two case studies: a simple water bottle LCA and an LCA of burger recipes.Results and discussion: The meta-analysis of two LCI databases shows that there is no single correct approximation of correlation between aggregated datasets. The case studies show that the uncertainty of single-product LCA using aggregated datasets is usually underestimated when the correlation across datasets is ignored and that the magnitude of the underestimation is dependent on the system being analysed and the LCIA method chosen. Comparative LCA results show that independent sampling of aggregated datasets drastically overestimates the uncertainty of comparative metrics. The approach based on dependently presampled results yields results functionally identical to those obtained by Monte Carlo analysis using unit process datasets with a negligible computation time.Conclusions: Independent sampling should not be used for comparative LCA. Moreover, the use of a one-size-fits-all correction factor to correct the calculated variability under independent sampling, as proposed elsewhere, is generally inadequate. The proposed approximate analytical approach is useful to estimate the importance of the covariance of aggregated datasets but not for comparative LCA. The approach based on dependently presampled results provides quick and correct results and has been implemented in EcodEX, a streamlined LCA software used by Nestlé. Dependently presampled results can be used for streamlined LCA software tools. Both presampling and analytical solutions require a preliminary one-time calculation of dependent samples for all aggregated datasets, which could be centrally done by database providers. The dependent presampling approach can be applied to other aspects of the LCA calculation chain. [ABSTRACT FROM AUTHOR]

Life cycle assessment (LCA) was applied to evaluate two wastewater treatment plant (WWTP) scenarios in Latin America and the Caribbean (LAC): extended aeration (EA) and pond system (PS). The main goal was to compare the environmental performance of two WWTP technologies across all environmental impact categories in selected methods when developing new WWTP projects. As a complementary goal, we analyzed how regionalization enhances LCA interpretation through a case study illustrating the spatial variability of WWTP results for 22 Latin American and Caribbean countries. A generic LCA relying on averaged primary data from 158 WWTPs was first performed based on three LCIA methodologies: ReCiPe, IMPACT World+ (IW+) and Impact 2002+. The results were used to identify the parameters that most influence the impact scores and test the sensitivity of the choice of LCIA methodology on the conclusions. While EA is the most impactful scenario for the human health (HH) and ecosystem quality (EQ) indicators according to Impact 2002+, ReCiPe considers it to be the least impacting option. This is mainly due to the fact that ReCiPe includes the contribution of global warming impacts at the damage level whereas IMPACT 2002+ does not. For the same reason, IW+ favours EA for the HH indicator, which is dominated by global warming impacts. However, for EQ, the PS scenario scores better because of the lower relative importance of global warming impacts (GWP) as compared to eutrophication impacts (FE) at the damage level. Both the IW+ and ReCiPe methodologies point to a trade-off between the two impact categories, which dominate the impact scores for this area of protection. A sensitivity analysis was therefore carried out at the inventory level considering regional grid electricity mixes and at the impact assessment level characterizing eutrophying emissions from WWTPs with the regional CFs for the 22 LAC countries provided by the IW+ model. Results from the IW+ analysis showed that the operating conditions of WWTP in countries where 43–80% of electricity is produced from fossil fuel tend to favour PS for the EQ and HH damage categories. Operating conditions in countries with an electricity mix of over 60% hydropower favour EA due to the significant decrease in greenhouse gas emissions for the EQ and HH damage categories. The location where a WWTP operates also influences the results of the impact assessment. For example, locations with higher eutrophication characterization factors such as Brazil, where the residence time of water is higher, do not tend to favour scenarios with higher eutrophying emissions such as EA with higher EQ impact scores as compared to PS. We concluded that regionalization, both of the inventory and characterization factors, show the potential for adding relevance and discriminating power to the LCA. To address regionalization it in standard LCA practice we propose a pragmatic and stepwise iterative approach that makes it possible to regionalize the greatest contributing inventory and the most impactful assessment flow. Nevertheless, it is important to note that we only addressed the uncertainty related to known spatial variability and that it may be of major interest to apply a similar stepwise approach to any other type of uncertainty. [ABSTRACT FROM AUTHOR]

Soils are one of earth's essential natural resources, supporting nearly all terrestrial life. By and large, current life cycle impact assessment (LCIA) methodologies are limited in their assessment of potential land use impacts in terms of terrestrial biodiversity loss. The land use life cycle impact assessment (LULCIA) project spearheaded by the United Nations Environment Programme/ Society of Environmental Toxicology and Chemistry (UNEP/SETAC) Life Cycle Initiative recently broadened the scope of land use evaluation in life cycle assessment (LCA) by encompassing six additional indicators that represent ecosystem provision and regulation services, as defined in the Millennium Ecosystem Assessment (2005). Although LCIA methodology is more comprehensive with regards to relevant impact pathways linked to land use, the development could potentially decrease the capacity of LCA as a decision support system by increasing the number of indicators from one to seven for the assessment of the land use impact category alone. To overcome this limitation, the project proposes a new LCIA method to estimate the decrease in value of the ecosystem services provided to society due to land use. The six midpoint land use indicators proposed by the LULCIA project are further modeled into a new area of protection, resources and ecosystem services, based on a functional approach. To do so, indicators expressed in biophysical units are converted into monetary units based on the economic valuation of the reduction of a given ecosystem service. The loss of provision services biotic production and fresh water recharge are estimated through productivity loss and water supply cost, respectively. The regulation services erosion resistance and mechanical and physicochemical water filtration are estimated through the cost of erosion mitigation measures and water purification process costs, respectively. The climate regulation potential is estimated through the social carbon cost: a decrease in carbon sequestration by soils is considered equivalent to an amount of carbon emitted in the atmosphere. We also propose to consider the local socioeconomic context by evaluating the economic adaptation capacity of countries: impacts on the resources and ecosystem services area of protection are only accounted for when the country has the capacity to adapt (while indirect impacts would be calculated by assessing the burdens of the adaptation scenario by performing a full LCA of these adaptation measures). The application of the method is illustrated through a case study evaluating the cradle-to-gate land use impacts of three bio-based polymers (biopolyethylene, polylactic acid and thermoplastic starch) produced in Brazil, Italy, Thailand and the United States. Impact scores are not only influenced by the biophysical specificity of the studied systems (e.g. crop yield affecting the inventory flow, type of biome affecting impact characterisation) but also by the local socioeconomic capacity to compensate for an ecosystem service loss and available compensation measures and technologies. In this case study, thermoplastic starch appears to have fewer impacts on land use and ecosystem services than biopolyethylene or polylactic acid. Overall, the research demonstrates the feasibility of further modeling the biophysical indicators of land use into an economic metric. This additional and complementary modeling step is meant to facilitate the interpretation of LCA results, enabling discussions on the relevance of the biophysical indicators affecting the loss of ecosystem services from land use. It may also be used as an explicit weighting scheme to aggregate the midpoint results into a single value expressing the social cost to compensate for the loss of the ecosystem services. [ABSTRACT FROM AUTHOR]

Purpose: The WULCA group, active since 2007 on Water Use in LCA, commenced the development of consensus-based indicators in January 2014. This activity is planned to last 2 years and covers human health, ecosystem quality, and a stress-based indicator. This latter encompasses potential deprivation of both ecosystem and human, hence aiming to represent potential impacts more comprehensively than any other available LCA-oriented method assessing the 'water scarcity footprint' (ISO 2014). Methods: A series of three expert workshops, including non-LCA experts from hydrology, eco-hydrology, and water supply science, was organized specifically on the topic of this generic midpoint indicator. They were held in Zurich on 10th September, in San Francisco on 5th October and in Tsukuba on 27th October 2014. In total 49 experts attended. The specific objectives of the workshops were twofold. First, it was to present the identified options of the stress-based indicator narrowed down by the active members of WULCA during the first 8 months of the project and to receive comments on the relevance, usefulness, acceptability, and focus of the selected indicator. Second, the workshop covered different challenges in the modeling of the indicator and presented the experts with background information and specific questions. This paper summarizes the discussions and outcome of these workshops. Where no agreement was reached, the working group of active members is considering all inputs received and continues the work. Results and discussion: The discussion covered first the question to be answered by such indicator, resulting on an agreement on the evaluation of the potential to deprive other users of water, independently of who the user is (i.e., human or ecosystems). Special attention was given to the special case of arid areas as well as the definition of environmental water requirements. Specific modeling challenges were then addressed: definition and quantification of human and ecosystem water demand, consideration of green water and terrestrial ecosystems, sources of data, distinction of groundwater and surface water, and temporal and geographical resolution. Conclusions: The input, decisions, and points of discussion were compiled and brought back within the group of active members. The group is using the recommendations and works further on the harmonization of the points of disagreement. It is expected that a selection of indicators representing different ways to address the most important issues will be produced and tested in spring 2015. The analysis of the result should lead to a provisional recommendation by summer 2015. [ABSTRACT FROM AUTHOR]

Purpose: In the past decade, several methods have emerged to quantify water scarcity, water availability and the human health impacts of water use. It was recommended that a quantitative comparison of methods should be performed to describe similar impact pathways, namely water scarcity and human health impacts from water deprivation. This is precisely the goal of this paper, which aims to (1) identify the key relevant modeling choices that explain the main differences between characterization models leading to the same impact indicators; (2) quantify the significance of the differences between methods, and (3) discuss the main methodological choices in order to guide method development and harmonization efforts. Methods: The modeling choices are analysed for similarity of results (using mean relative difference) and model response consistency (through rank correlation coefficient). Uncertainty data associated with the choice of model are provided for each of the models analysed, and an average value is provided as a tool for sensitivity analyses. Results: The results determined the modeling choices that significantly influence the indicators and should be further analysed and harmonised, such as the regional scale at which the scarcity indicator is calculated, the sources of underlying input data and the function adopted to describe the relationship between modeled scarcity indicators and the original withdrawal-to-availability or consumption-to-availability ratios. The inclusion or exclusion of impacts from domestic user deprivation and the inclusion or exclusion of trade effects both strongly influence human health impacts. At both midpoint and endpoint, the comparison showed that considering reduced water availability due to degradation in water quality, in addition to a reduction in water quantity, greatly influences results. Other choices are less significant in most regions of the world. Maps are provided to identify the regions in which such choices are relevant. Conclusions: This paper provides useful insights to better understand scarcity, availability and human health impact models for water use and identifies the key relevant modeling choices and differences, making it possible to quantify model uncertainty and the significance of these choices in a specific regional context. Maps of regions where these specific choices are of importance were generated to guide practitioners in identifying locations for sensitivity analyses in water footprint studies. Finally, deconstructing the existing models and highlighting the differences and similarities has helped to determine building blocks to support the development of a consensual method. [ABSTRACT FROM AUTHOR]

Purpose: To assess the diverse environmental impacts of land use, a standardization of quantifying land use elementary flows is needed in life cycle assessment (LCA). The purpose of this paper is to propose how to standardize the land use classification and how to regionalize land use elementary flows. Materials and methods: In life cycle inventories, land occupation and transformation are elementary flows providing relevant information on the type and location of land use for land use impact assessment. To find a suitable land use classification system for LCA, existing global land cover classification systems and global approaches to define biogeographical regions are reviewed. Results and discussion: A new multi-level classification of land use is presented. It consists of four levels of detail ranging from very general global land cover classes to more refined categories and very specific categories indicating land use intensities. Regionalization is built on five levels, first distinguishing between terrestrial, freshwater, and marine biomes and further specifying climatic regions, specific biomes, ecoregions and finally indicating the exact geo-referenced information of land use. Current land use inventories and impact assessment methods do not always match and hinder a comprehensive assessment of land use impact. A standardized definition of land use types and geographic location helps to overcome this gap and provides the opportunity to test the optimal resolution of land cover types and regionalization for each impact pathway. Conclusions and recommendation: The presented approach provides the necessary flexibility to providers of inventories and developers of impact assessment methods. To simplify inventories and impact assessment methods of land use, we need to find archetypical situations across impact pathways, land use types and regions, and aggregate inventory entries and methods accordingly. [ABSTRACT FROM AUTHOR]

Purpose: As a consequence of the multi-functionality of land, the impact assessment of land use in Life Cycle Impact Assessment requires the modelling of several impact pathways covering biodiversity and ecosystem services. To provide consistency amongst these separate impact pathways, general principles for their modelling are provided in this paper. These are refinements to the principles that have already been proposed in publications by the UNEP-SETAC Life Cycle Initiative. In particular, this paper addresses the calculation of land use interventions and land use impacts, the issue of impact reversibility, the spatial and temporal distribution of such impacts and the assessment of absolute or relative ecosystem quality changes. Based on this, we propose a guideline to build methods for land use impact assessment in Life Cycle Assessment (LCA). Results: Recommendations are given for the development of new characterization models and for which a series of key elements should explicitly be stated, such as the modelled land use impact pathways, the land use/cover typology covered, the level of biogeographical differentiation used for the characterization factors, the reference land use situation used and if relative or absolute quality changes are used to calculate land use impacts. Moreover, for an application of the characterisation factors (CFs) in an LCA study, data collection should be transparent with respect to the data input required from the land use inventory and the regeneration times. Indications on how generic CFs can be used for the background system as well as how spatial-based CFs can be calculated for the foreground system in a specific LCA study and how land use change is to be allocated should be detailed. Finally, it becomes necessary to justify the modelling period for which land use impacts of land transformation and occupation are calculated and how uncertainty is accounted for. Discussion: The presented guideline is based on a number of assumptions: Discrete land use types are sufficient for an assessment of land use impacts; ecosystem quality remains constant over time of occupation; time and area of occupation are substitutable; transformation time is negligible; regeneration is linear and independent from land use history and landscape configuration; biodiversity and multiple ecosystem services are independent; the ecological impact is linearly increasing with the intervention; and there is no interaction between land use and other drivers such as climate change. These assumptions might influence the results of land use Life Cycle Impact Assessment and need to be critically reflected. Conclusions and recommendations: In this and the other papers of the special issue, we presented the principles and recommendations for the calculation of land use impacts on biodiversity and ecosystem services on a global scale. In the framework of LCA, they are mainly used for the assessment of land use impacts in the background system. The main areas for further development are the link to regional ecological models running in the foreground system, relative weighting of the ecosystem services midpoints and indirect land use. [ABSTRACT FROM AUTHOR]

Purpose: Rarely considered in environmental assessment methods, potential land use impacts on a series of ecosystem services must be accounted for in widely used decision-making tools such as life cycle assessment (LCA). The main goal of this study is to provide an operational life cycle impact assessment characterization method that addresses land use impacts at a global scale by developing spatially differentiated characterization factors (CFs) and assessing the extent of their spatial variability using different regionalization levels. Methods: The proposed method follows the recommendations of previous work and falls within the framework and principles for land use impact assessment established by the United Nations Environment Programme/Society of Environmental Toxicology and Chemistry Life Cycle Initiative. Based on the spatial approach suggested by Saad et al. (Int J Life Cycle Assess 16: 198-211, ), the intended impact pathways that are modeled pertain to impacts on ecosystem services damage potential and focus on three major ecosystem services: (1) erosion regulation potential, (2) freshwater regulation potential, and (3) water purification potential. Spatially-differentiated CFs were calculated for each biogeographic region of all three regionalization scale (Holdridge life regions, Holdridge life zones, and terrestrial biomes) along with a nonspatial world average level. In addition, seven land use types were assessed considering both land occupation and land transformation interventions. Results and discussion: A comprehensive analysis of the results indicates that, when compared to all resolution schemes, the world generic averaged CF can deviate for various ecosystem types. In the case of groundwater recharge potential impacts, this range varied up to factors of 7, 4.7, and 3 when using the Holdridge life zones, the Holdridge regions, and the terrestrial biomes regionalization levels, respectively. This validates the importance of introducing a regionalized assessment and highlights how a finer scale increases the level of detail and consequently the discriminating power across several biogeographic regions, which could not have been captured using a coarser scale. In practice, the implementation of such regionalized CFs suggests that an LCA practitioner must identify the ecosystem in which land occupation or transformation activities occur in addition to the traditional inventory data required-namely, the land use activity and the inventory flow. Conclusions: The variability of CFs across all three regionalization levels provides an indication of the uncertainty linked to nonspatial CFs. Among other assumptions and value choices made throughout the study, the use of ecological borders over political boundaries was deemed more relevant to the interpretation of environmental issues related to specific functional ecosystem behaviors. [ABSTRACT FROM AUTHOR]

Purpose: In recent years, several methods have been developed which propose different freshwater use inventory schemes and impact assessment characterization models considering various cause-effect chain relationships. This work reviewed a multitude of methods and indicators for freshwater use potentially applicable in life cycle assessment (LCA). This review is used as a basis to identify the key elements to build a scientific consensus for operational characterization methods for LCA. Methods: This evaluation builds on the criteria and procedure developed within the International Reference Life Cycle Data System Handbook and has been adapted for the purpose of this project. It therefore includes (1) description of relevant cause-effect chains, (2) definition of criteria to evaluate the existing methods, (3) development of sub-criteria specific to freshwater use, and (4) description and review of existing methods addressing freshwater in LCA. Results and discussion: No single method is available which comprehensively describes all potential impacts derived from freshwater use. However, this review highlights several key findings to design a characterization method encompassing all the impact pathways of the assessment of freshwater use and consumption in life cycle assessment framework as the following: (1) in most of databases and methods, consistent freshwater balances are not reported either because output is not considered or because polluted freshwater is recalculated based on a critical dilution approach; (2) at the midpoint level, most methods are related to water scarcity index and correspond to the methodological choice of an indicator simplified in terms of the number of parameters (scarcity) and freshwater uses (freshwater consumption or freshwater withdrawal) considered. More comprehensive scarcity indices distinguish different freshwater types and functionalities. (3) At the endpoint level, several methods already exist which report results in units compatible with traditional human health and ecosystem quality damage and cover various cause-effect chains, e.g., the decrease of terrestrial biodiversity due to freshwater consumption. (4) Midpoint and endpoint indicators have various levels of spatial differentiation, i.e., generic factors with no differentiation at all, or country, watershed, and grid cell differentiation. Conclusions: Existing databases should be (1) completed with input and output freshwater flow differentiated according to water types based on its origin (surface water, groundwater, and precipitation water stored as soil moisture), (2) regionalized, and (3) if possible, characterized with a set of quality parameters. The assessment of impacts related to freshwater use is possible by assembling methods in a comprehensive methodology to characterize each use adequately. [ABSTRACT FROM AUTHOR]

Purpose: Life cycle impact assessment (LCIA) is a field of active development. The last decade has seen prolific publication of new impact assessment methods covering many different impact categories and providing characterization factors that often deviate from each other for the same substance and impact. The LCA standard ISO 14044 is rather general and unspecific in its requirements and offers little help to the LCA practitioner who needs to make a choice. With the aim to identify the best among existing characterization models and provide recommendations to the LCA practitioner, a study was performed for the Joint Research Centre of the European Commission (JRC). Methods: Existing LCIA methods were collected and their individual characterization models identified at both midpoint and endpoint levels and supplemented with other environmental models of potential use for LCIA. No new developments of characterization models or factors were done in the project. From a total of 156 models, 91 were short listed as possible candidates for a recommendation within their impact category. Criteria were developed for analyzing the models within each impact category. The criteria addressed both scientific qualities and stakeholder acceptance. The criteria were reviewed by external experts and stakeholders and applied in a comprehensive analysis of the short-listed characterization models (the total number of criteria varied between 35 and 50 per impact category). For each impact category, the analysis concluded with identification of the best among the existing characterization models. If the identified model was of sufficient quality, it was recommended by the JRC. Analysis and recommendation process involved hearing of both scientific experts and stakeholders. Results and recommendations: Recommendations were developed for 14 impact categories at midpoint level, and among these recommendations, three were classified as 'satisfactory' while ten were 'in need of some improvements' and one was so weak that it has 'to be applied with caution.' For some of the impact categories, the classification of the recommended model varied with the type of substance. At endpoint level, recommendations were only found relevant for three impact categories. For the rest, the quality of the existing methods was too weak, and the methods that came out best in the analysis were classified as 'interim,' i.e., not recommended by the JRC but suitable to provide an initial basis for further development. Discussion, conclusions, and outlook: The level of characterization modeling at midpoint level has improved considerably over the last decade and now also considers important aspects like geographical differentiation and combination of midpoint and endpoint characterization, although the latter is in clear need for further development. With the realization of the potential importance of geographical differentiation comes the need for characterization models that are able to produce characterization factors that are representative for different continents and still support aggregation of impact scores over the whole life cycle. For the impact categories human toxicity and ecotoxicity, we are now able to recommend a model, but the number of chemical substances in common use is so high that there is a need to address the substance data shortage and calculate characterization factors for many new substances. Another unresolved issue is the need for quantitative information about the uncertainties that accompany the characterization factors. This is still only adequately addressed for one or two impact categories at midpoint, and this should be a focus point in future research. The dynamic character of LCIA research means that what is best practice will change quickly in time. The characterization methods presented in this paper represent what was best practice in 2008-2009. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this paper is to provide science-based consensus and guidance for health effects modelling in comparative assessments based on human exposure and toxicity. This aim is achieved by (a) describing the USEtox™ exposure and toxicity models representing consensus and recommended modelling practice, (b) identifying key mechanisms influencing human exposure and toxicity effects of chemical emissions, (c) extending substance coverage. Methods: The methods section of this paper contains a detailed documentation of both the human exposure and toxic effects models of USEtox™, to determine impacts on human health per kilogram substance emitted in different compartments. These are considered as scientific consensus and therefore recommended practice for comparative toxic impact assessment. The framework of the exposure model is described in details including the modelling of each exposure pathway considered (i.e. inhalation through air, ingestion through (a) drinking water, (b) agricultural produce, (c) meat and milk, and (d) fish). The calculation of human health effect factors for cancer and non-cancer effects via ingestion and inhalation exposure respectively is described. This section also includes discussions regarding parameterisation and estimation of input data needed, including route-to-route and acute-to-chronic extrapolations. Results and discussion: For most chemicals in USEtox™, inhalation, above-ground agricultural produce, and fish are the important exposure pathways with key driving factors being the compartment and place of emission, partitioning, degradation, bioaccumulation and bioconcentration, and dietary habits of the population. For inhalation, the population density is the key factor driving the intake, thus the importance to differentiate emissions in urban areas, except for very persistent and mobile chemicals that are taken in by the global population independently from their place of emission. The analysis of carcinogenic potency (TD) when volatile chemicals are administrated to rats and mice by both inhalation and an oral route suggests that results by one route can reasonably be used to represent another route. However, we first identify and mark as interim chemicals for which observed tumours are directly related to a given exposure route (e.g. for nasal or lung, or gastrointestinal cancers) or for which absorbed fraction by inhalation and by oral route differ greatly. Conclusions: A documentation of the human exposure and toxicity models of USEtox™ is provided, and key factors driving the human health characterisation factor are identified. Approaches are proposed to derive human toxic effect factors and expand the number of chemicals in USEtox™, primarily by extrapolating from an oral route to exposure in air (and optionally acute-to-chronic). Some exposure pathways (e.g. indoor inhalation, pesticide residues, dermal exposure) will be included in a later stage. USEtox™ is applicable in various comparative toxicity impact assessments and not limited to LCA. [ABSTRACT FROM AUTHOR]

Purpose: The USEtox model was developed in a scientific consensus process involving comparison of and harmonization between existing environmental multimedia fate models. USEtox quantitatively models the continuum from chemical emission to freshwater ecosystem toxicity via chemical-specific characterization factors (CFs) for Life Cycle Impact Assessment (LCIA). This work provides understanding of the key mechanisms and chemical parameters influencing fate in the environment and impact on aquatic ecosystems. Materials and method: USEtox incorporates a matrix framework for multimedia modeling, allowing separation of fate, exposure, and ecotoxicity effects in the determination of an overall CF. Current best practices, such as incorporation of intermittent rain and effect factors (EF) based on substance toxicity across species, are implemented in the model. The USEtox database provides a dataset of over 3,000 organic chemicals, of which approximately 2,500 have freshwater EFs. Freshwater characterization factors for these substances, with a special focus on a subset of chemicals with characteristic properties, were analyzed to understand the contributions of fate, exposure, and effect on the overall CFs. The approach was based on theoretical interpretation of the multimedia model components as well as multidimensional graphical analysis. Results and discussion: For direct emission of a substance to water, the EF strongly controls freshwater ecotoxicity, with a range of up to 10 orders of magnitude. In this release scenario, chemical-specific differences in environmental fate influence the CF for freshwater emissions by less than 2 orders of magnitude. However, for an emission to air or soil, the influence of the fate is more pronounced. Chemical partitioning properties between water, air, and soil may drive intermedia transfer, which may be limited by the often uncertain, media-specific degradation half-life. Intermedia transfer may be a function of landscape parameters as well; for example, direct transfer from air to freshwater is limited by the surface area of freshwater. Overall, these altered fate factors may decrease the CF up to 8 orders of magnitude. Conclusions: This work brings new clarity to the relative contributions of fate and freshwater ecotoxicity to the calculation of CFs. In concert with the USEtox database, which provides the most extensive compilation of CFs to date, these findings enable those undertaking LCIA to understand and contextualize existing and newly calculated CFs. [ABSTRACT FROM AUTHOR]

Freshwater scarcity is a problem in many areas of the world and will become one of the most sensitive environmental issues in coming decades. Existing life cycle assessment (LCA) methodologies generally do not provide assessment schemes or characterization factors of the potential environmental impacts of freshwater use or freshwater resource depletion. These assessments therefore do not account for the significant environmental consequences of the loss in quality and availability of freshwater. This paper aims to develop a framework to address this methodological limitation and to support further quantitative modeling of the cause–effect chain relationships of water use. The framework includes recommendations for life cycle inventory (LCI) modeling and provides a description of possible impact pathways for life cycle impact assessment (LCIA), including indicators on midpoint and endpoint levels that reflect different areas of protection (AoP). LCI of freshwater use aims to quantify changes in freshwater availability. The key elements affected by changes in availability are sufficient freshwater supplies for contemporary human users, ecosystems, and future generations, the latter referring to the renewability of the resource. Three midpoint categories are therefore proposed and linked to common AoP as applied in LCIA. We defined a set of water types, each representing an elementary flow. Water balances for each type allows the quantification of changes in freshwater availability. These values are recommended as results for the LCI of water use. Insufficient freshwater supplies for contemporary human users can mean freshwater deficits for human uses, which is the first midpoint impact category ultimately affecting the AoP of human life; freshwater deficits in ecosystems is the second proposed midpoint impact category and is linked to the AoP biotic environment. Finally, the last midpoint category is freshwater depletion caused by intensive overuse that exceeds the regeneration rate, which itself is ultimately linked to the AoP abiotic environment. Depending on the regional context, the development of scenarios aimed to compensate for the lack of water for specific uses by using backup technologies (e.g., saltwater treatment, the import of agricultural goods) can avoid generating direct impacts on the midpoint impact category freshwater deficits for human uses. Indirect impacts must be assessed through an extension of system boundaries including these backup technologies. Because freshwater is a resource with high spatial and temporal variability, the proposed framework discusses aspects of regionalization in relationship to data availability, appropriate spatial and temporal resolution, and software capacities to support calculations. The framework provides recommendations for the development of operational LCA methods for water use. It establishes the link between LCI and LCIA, water-use mechanism models, and impact pathways to environmental damages in a consistent way. Based on this framework, next steps consist of the development of operational methods for both inventory modeling and impact assessment. [ABSTRACT FROM AUTHOR]

Background, aim, and scope This paper compares the life cycle assessment (LCA) of two packaging alternatives used for baby food produced by Nestlé: plastic pot and glass jar. The study considers the environmental impacts associated with packaging systems used to provide one baby food meal in France, Spain, and Germany in 2007. In addition, alternate logistical scenarios are considered which are independent of the two packaging options. The 200-g packaging size is selected as the basis for this study. Two other packaging sizes are assessed in the sensitivity analysis. Because results are intended to be disclosed to the public, this study underwent a critical review by an external panel of LCA experts. Materials and methods The LCA is performed in accordance to the international standards ISO 14040 and ISO 14044. The packaging systems include the packaging production, the product assembly, the preservation process, the distribution, and the packaging end-of-life. The production of the content (before preservation process), as well as the use phase are not taken into account as they are considered not to change when changing packaging. The inventory is based on data obtained from the baby food producer and the suppliers, data from the scientific literature, and data from the ecoinvent database. Special care is taken to implement a system expansion approach for end-of-life open and closed loop recycling and energy production (ISO 14044). A comprehensive impact assessment is performed using two life cycle impact assessment methodologies: IMPACT 2002+ and CML 2001. An extensive uncertainty analysis using Monte Carlo as well as an extensive sensitivity study are performed on the inventory and the reference flows, respectively. Results When looking at the impacts due to preservation process and packaging (considering identical distribution distances), we observe a small but significant environmental benefit of the plastic pot system over the glass jar system. Depending on the country, the impact is reduced by 14% to 27% for primary energy, 28% to 31% for global warming, 31% to 34% for respiratory inorganics, and 28% to 31% for terrestrial acidification/nutrification. The environmental benefit associated with the change in packaging mainly results from (a) production of plastic pot (including its end-of-life; 43% to 51% of total benefit), (b) lighter weight of packaging positively impacting transportation (20% to 35% of total benefit), and (c) new preservation process permitted by the plastic system (23% to 34% of total benefit). The jar or pot (including cap or lid, cluster, stretch film, and label) represents approximately half of the life cycle impacts, the logistics approximately one fourth, and the rest (especially on-site energy, tray, and hood) one fourth. Discussion The sensitivity analysis shows that assumptions made in the basic scenarios are rather conservative for plastic pots and that the conclusions for the 200-g packaging size also apply to other packaging sizes. The uncertainty analysis performed on the inventory for the German market situation shows that the plastic pot system has less impact than the glass jar system while considering similar distribution distances with a confidence level above 97% for most impact categories. There is opportunity for further improvement independent of the type of packaging used, such as by reducing distribution distances while still optimizing lot size.… [ABSTRACT FROM AUTHOR]

Background, aim and scope The methodological choices and framework to assess environmental impacts in life cycle assessment are still under discussion. Despite intensive developments worldwide, few attempts have been made hitherto to systematically present the role of different factors of characterisation models in life cycle impact assessment (LCIA). The aim of this study is to show how European average and country-dependent characterisation factors for acidifying and eutrophying emissions differ when using (a) acidifying and eutrophying potentials alone, (b) depositions from an atmospheric dispersion model or (c) critical loads in conjunction with those depositions. Furthermore, in the latter case, the contributions of emissions, an atmospheric transport model and critical loads to changes in characterisation factors of NO2 are studied. In addition, the new characterisation factors based on the accumulated exceedance (AE) method are presented using updated emissions, a new atmospheric transport model and the latest critical loads. Materials and methods In this study, characterisation factors for acidifying and eutrophying emissions are calculated by three different methods. In the 'no fate' (NF) methods, acidifying and eutrophying potentials alone are considered as characterisation factors. In the 'only above terrestrial environment' (OT) approach, characterisation factors are based on the deposition of the acidifying or eutrophying substances to terrestrial land surfaces. The third method is the so-called AE method in which critical loads are used in conjunction with depositions. The results of the methods are compared both at the European and the country level using weighted mean, weighted standard deviation, minimum and maximum values. To illustrate the sensitivity of the AE method, changes in European emissions, employed atmospheric dispersion model and the critical loads database are conducted step-by-step, and the differences between the results are analysed. Results and discussion For European average characterisation factors, the three characterisation methods of acidification produce results in which the contributions of NH3, NO2 and SO2 to the acidification indicator do not differ much within each method when 1 kg of each acidifying substance is emitted. However, the NF methods cannot describe any spatial aspects of environmental problems. Both OT and AE methods show that the spatial aspects play an important role in the characterisation factors. The AE method results in greater differentiations between country-dependent characterisation factors than does the OT method. In addition, the results of the AE and OT methods differ from each other for individual countries.… [ABSTRACT FROM AUTHOR]

A correction to the article "Global Guidance on Environmental Life Cycle Impact Assessment Indicators: Findings of the Scoping Phase" in an issue of the "International Journal of Life Cycle Assessment" is presented.

Abstract: Life cycle assessment (LCA) is recognized as a powerful method to evaluate the environmental impacts of a product. However, its use in product development processes remains marginal. While authors have advanced different technical solutions to facilitate or accelerate the conduct of an LCA, current methods are generally still not adapted to designers, who often lack the time and expertise to make use of LCA results in their day-to-day activities. This paper addresses the issue by proposing a Business Process Reengineering (BPR) methodology that can be used to develop suitable Decision-Support Systems (DSS). These systems would enhance the use of LCA results in early design phases. The development of such a tool in a particular case study illustrates how its development is aligned with the current designer expectations and constraints. The case study is built on the results of a previous LCA of a known strategic product and includes a library with existing newly characterized materials and components, making it possible to evaluate several design alternatives from an environmental and cost perspective, using LCA as a predictive tool rather than a retrospective one. [Copyright &y& Elsevier]

The lack of temporal information is an important limitation of life cycle assessment (LCA). A dynamic LCA approach is proposed to improve the accuracy of LCA by addressing the inconsistency of temporal assessment. This approach consists of first computing a dynamic life cycle inventory (LCI), considering the temporal profile of emissions. Then, time-dependent characterization factors are calculated to assess the dynamic LCI in real-time impact scores for any given time horizon. Although generally applicable to any impact category, this approach is developed here for global warming, based on the radiative forcing concept. This case study demonstrates that the use of global warming potentials for a given time horizon to characterize greenhouse gas emissions leads to an inconsistency between the time frame chosen for the analysis and the time period covered by the LCA results. Dynamic LCA is applied to the US EPA LCA on renewable fuels, which compares the life cycle greenhouse gas emissions of different biofuels with fossil fuels including land-use change emissions. The comparison of the results obtained with both traditional and dynamic LCA approaches shows that the difference can be important enough to change the conclusions on whether or not a biofuel meets some given global warming reduction targets. [ABSTRACT FROM AUTHOR]

The need for circularity assessment tools to prevent undesirable effects (e.g. recycling processes requiring more energy) is gaining recognition. Preserving resources and relieving pollution reservoirs are both necessary conditions to achieve a sustainable circular economy (CE), and the corresponding assessment tools should be selected accordingly. We chose life cycle assessment (LCA) and the Material Circularity Indicator (MCI). In this paper, we tested the tools through two case studies from the tire industry. The Brazilian case proposes three scenarios to process used tires: baseline, retreading and regrooving. The European case suggests collecting secondary material from end-of-life (EoL) tires to produce recycled content (RC) at 4% and 10% rates. These rates were chosen to illustrate the change in tire performance in the use phase. We propose an approach to discuss MCI and LCA results that identifies four pathways toward or away from the CE goal: coupling, decoupling, trade-off on resources or trade-off on reservoirs. The case studies reveal that extending lifetime through retreading and introducing recycled material improves the MCI of a tire but do not necessarily improve impacts on human health and ecosystems. Also, discrepancies in the results between the MCI and the LCA's resource indicator highlight relevant issues for new CE experts seeking to design assessment tools. Even though LCA provides a broader scope than the MCI, it still reflects a relative contribution to environmental sustainability while the MCI focuses on micro-scale improvements in resource use efficiency. [ABSTRACT FROM AUTHOR]

Addressing the spatial dimension in life cycle assessment (LCA) appears to be a promising avenue to reduce the uncertainty of LCA results. However, to our knowledge, there is no comprehensive literature review on how to integrate geographic aspects at every LCA stage. This study aims to create a common language and build a framework guiding the LCA community to integrate the spatial dimension in LCA towards three specific objectives: (a) to review the literature to synthesize and classify current recommendations and approaches to integrate the spatial dimension in LCA, (b) to analyze each identified approach based on their level of relevance, development and operationalization and (c) to formulate recommendations on how to integrate the spatial dimension in LCA. From the literature review, 33 recommendations and 37 approaches were identified. The approaches were classified according to the main issue they aim to address when integrating the spatial dimension in LCA: goal and scope, inventory regionalization, inventory spatialization, regionalized impact calculation, impact regionalization, interpretation and application in LCA software. Then, each approach was critically and qualitatively assessed against the three following criteria: relevance of the approach, level of development and level of operationalization. Short- and long-term recommendations on how to address spatial dimension in LCA for each identified issue and for the different stakeholders in the LCA community were derived from the critical analysis. A decision-support diagram was set up to help for the implementation of the short-term state-of-the-art recommendations and guide LCA practitioners to prioritize inventory regionalization and spatialization efforts. [ABSTRACT FROM AUTHOR]

Abstract: This paper aims to advance regional worldwide source–receptor relationships, providing fate factors for acidifying and eutrophying air emissions (NO x , HNO3, SO2, SO4 and NH3) to be used within life cycle impact assessment. A simulation for the reference year 2005 of the three-dimensional global scale tropospheric GEOS-Chem model was used as the basis of a novel methodological approach to derive source–receptor matrices (SRMs) whose elements are fate factors at a global 2° × 2.5° grid. This new approach makes it possible to assess the impact of transboundary emissions while maintaining regional scale emission differentiation. These 2° × 2.5° grid resolution fate factors were later aggregated at continental and country resolutions using emission weighting. Continental fate factor results showed that 50–70% of nitrogen oxides (NO x , HNO3) and sulfur oxides (SO2, SO4) and approximately 80% of ammonia (NH3) emissions will deposit on the same continent. Results showed that the developed fate factor derivation approach was within a ±10% agreement with GEOS-Chem simulations in which fate factors were determined by withdrawing the regional emission inventory over Canada and in ±50% agreement with current state-of-the-art LCIA fate factors (calculated with the European Monitoring and Evaluation Programme (EMEP) model). The SRMs outlined in this paper facilitate further modeling developments without having to run the underlying tropospheric model, thus opening the door to the assessment of the regional life cycle inventories of a global economy. [Copyright &y& Elsevier]

Abstract: This paper aims to evaluate the environmental burdens associated with spray dried soluble coffee over its entire life cycle and compare it with drip filter coffee and capsule espresso coffee. It particularly aims to identify critical environmental issues and responsibilities along the whole life cycle chain of spray dried coffee. This life cycle assessment (LCA) specifically uses foreground data obtained directly from coffee manufacturers and suppliers. Aside from energy consumption and greenhouse gases emissions, water footprint is also studied in detail, including regionalization of water impacts based on the ecological scarcity method 2006. Other impact categories are screened using the IMPACT 2002+ impact assessment method. The overall LCA results for a 1dl cup of spray dried soluble coffee amounts approximately to 1MJ of primary non-renewable energy consumption, to emissions of 0.07kg of CO2-eq, and between 3 and 10l of non-turbined water use, depending on whether or not the coffee cultivation is irrigated and wet treated. When considering turbined water, use can be up to 400l of water per cup. Pouch – and to a lesser extent metal can packaging alternatives – show lower environmental burdens than glass or sticks. On average, about one half of the environmental footprint occurs at a life cycle stage under the control of the coffee producer or its suppliers (i.e., during cultivation, treatment, processing, packaging up to distribution, along with advertising) and the other half at a stage controlled by the user (shopping, appliances manufacturing, use and waste disposal). Key environmental parameters of spray dried soluble coffee are the amount of extra water boiled and the efficiency of cup cleaning during use phase, whether the coffee is irrigated or not, as well as the type and amount of fertilizer used in the coffee field. The packaging contributes to 10% of the overall life cycle impacts. Compared to other coffee alternatives, spray dried soluble coffee uses less energy and has a lower environmental footprint than capsule espresso coffee or drip filter coffee, the latter having the highest environmental impacts on a per cup basis. This study shows that a broad LCA approach is needed to help industry to minimize the environmental burdens directly related to their products. Including all processes of the entire system is necessary i) to get a comprehensive environmental footprint of the product system with respect to sustainable production and consumption, ii) to share stakeholders responsibility along the entire product life cycle, and iii) to avoid problem shifting between different life cycle stages. [Copyright &y& Elsevier]

The article focuses on a scientific consensus-building procedure for a transparent Life Cycle Impact Assessment (LCIA) consensus model applied to chemical emissions. It states that LCIA examines the possible impacts that chemical emissions from a product's lifetime may have on the environment and human health. It mentions that LCIA focuses on comparative assessment, utilizing methods adapted from risk assessment. It offers suggestions for other consensus-building projects, including that it is important to create an open-minded atmosphere and minimize the obstructing influence of competition between scientists, and that it was useful to agree on common criteria for characterization models which was detached from the actual performance of the models.