# The International Journal of Life Cycle Assessment

Online ISSN: 1614-7502
Recent publications
Article
Introduction Many methodological papers report a comparison of methods for LCA, for instance comparing different impact assessment systems, or developing streamlined methods. A popular way to do so is by studying the differences of results for a number of products. We refer to such studies as quasi-empirical meta-comparisons. Review of existing approaches A scan of the literature reveals that many different methods and indicators are employed: contribution analyses, Pearson correlations, Spearman correlations, regression, significance tests, neural networks, etc. Critical discussion We critically examine the current practice and conclude that some of the widely used methods are associated with important deficits. A new approach Inspired by the critical analysis, we develop a new approach for meta-comparative LCA, based on directional statistics. We apply it to several real-world test cases, and analyze its performance vis-à-vis traditional regression-based approaches. Conclusion The method on the basis of directional statistics withstands the tests of changing the scale and unit of the training data. As such, it holds a promise for improved method comparisons.

Article
Purpose Assessing the potential impacts (characterization) of mineral resource use in life cycle impact assessment (LCIA) has long been debated. One of the most crucial challenges in the characterization models for mineral resource use is the consideration of the changing demand and availability of in-use stocks in the future, which is relevant to the global population and economy growth as well as the increasing low-carbon technologies. We propose an extended characterization model to assess the potential impacts for arbitrary time horizons, considering future demand changes and the availability of in-use stock: temporally explicit abiotic depletion potential (TADP). Methods The TADP was developed based on abiotic depletion potential (ADP), which is a widely used characterization model for mineral resource use. While the ADP assesses the potential impacts of mineral resource use based on a natural stock estimate and the current extraction rate, the TADP adopts an average extraction rate for arbitrary time horizons. The average extraction rate was estimated using material flow analysis considering future demand changes and recycling under the five shared socioeconomic pathways (SSPs). TADPs were calculated for six common metals: aluminum, copper, iron, lead, nickel, and zinc. Results and discussion As a result of calculating TADPs for the term by 2050 (TADP2050), compared to iron, all other metals showed larger values of characterization factors for all SSPs than the original ADPs. The TADP2050 of copper exhibited the largest difference with ADP among the six metals (approximately 1.9 times), which is mainly attributed to future demand growth. On the other hand, for the longer time perspective, the TADP2100 of lead and zinc exhibited larger differences with ADP than copper (approximately 2.8 times for zinc), which is mainly due to a relatively shorter lifetime for lead and a lower recycling rate for zinc. This suggests that the relative significance of the characterization factors of metals varies depending on the temporal perspective. Conclusions With the proposed characterization model, the potential impacts of mineral resource use can be assessed reflecting future situations for the selected time horizons. The results demonstrate that the consideration of future situations greatly influences the relative significance of the potential impacts of using different mineral resources in the results of LCIA studies. By expanding the coverage of mineral resources and future scenario analysis to other relevant factors, the TADP model can improve the robustness of the assessment and further support decision-making towards sustainable resource management.

Article
Purpose The construction sector is interested in considering environmental implications as necessary criteria for sustainability. In this regard, wood materials, especially engineering wood, are a promising choice for sustainable buildings. In some countries such as Malaysia, timber is rarely considered in the construction sector despite there being abundant access to wood. This is because of the scarcity of timber structures and the dominance of alternative materials such as steel and concrete. The cross-laminated timber-steel composite introduced in this research benefits both the wood and the steel markets leading to standardization and a more extensive market. At the same time, it contributes to environmentally friendly requirements. The main objective was to investigate timber applications in local construction and make proposals for its promotion. The new specimen described here could potentially enhance the strength of timber beams using steel plates. Four current structural methods have been chosen based on environmental and economic comparisons with a new composite structure. Methods The life cycle assessment (LCA) and life cycle cost (LCC) have been used to compare the performance of four current conventional structures. Results and discussion The results showed that the new proposed structure has lower emissions in all environmental categories, namely, Global Warming Potential (GWP), Human Carcinogenic Toxicity (HCT), Fossil Depletion Potential (FDP), Ozone Layer Depletion (OLD), Terrestrial Acidification (TA) and embodied energy. The results of the LCC are consistent with the environmental issue as the new composite has a lower cost over its entire life span. Conclusions The new structure provides a novel and sustainable alternative for the construction industry.

Article
Purpose The 17 Sustainable Development Goals (SDGs) and their 169 targets pose the most important framework for sustainable development worldwide. However, the contributions of products and companies to the SDGs using social and environmental life cycle assessment (S-LCA; E-LCA) have not been thoroughly addressed in the scientific literature. The purpose of this research is therefore to identify product-related targets, derive suitable indicators and develop a social life cycle impact assessment (S-LCIA) method. Methods To systematically select product-related targets, two questions are developed. The questions ask whether a product (a) has a direct impact on the achievement of the target or (b) if the companies along the life cycle that produce or offer the product have a direct influence on the achievement of the respective target. Suitable indicators are derived and adapted from generally accepted frameworks such as the Global Indicator Framework (GIF-SDG). To develop an S-LCIA method, the targets are translated into conditions beneficial or damaging to the achievement of the target to estimate the socio-economic impact of the product using a scale from +1 to −1. In cases where the targets remain vague, a systematic five-step approach to derive a quantifiable target involving five steps is applied. Results and discussion The main contribution of this paper is to propose a coherent method to measure the contribution of products to the targets. All 17 SDGs and 61 of the 169 targets (36%) were evaluated as product-related. For 57% of the product-related targets, indicators from the GIF-SDGs could at least partly be used after slight adaptations, while for the remaining 43% of the product-related targets, indicators were taken from other frameworks or sources or had to be added. In total, 45 indicators have been identified to be suitable for assessing the potential contribution of products to the 61 targets. To illustrate the systematic five-step approach to quantitatively assess the contribution of products to the targets, five types of contribution functions are presented in detail. Conclusions The presented method allows companies to analyse their impact and that of their products on the targets both within their own company and in the supply chain. As especially the latter is increasingly demanded by supply chain laws in different countries such as France, the Netherlands or the UK, the method fills an important research gap. However, future research to examine the proposed approach, the derived indicators and the impact assessment method is strongly encouraged.

Article
Purpose Packaging can be a critical aspect in the environmental performance of pharmaceutical products; however, few life cycle assessment studies were implemented for pharmaceutical packaging. The main goal is to assess the environmental life cycle impacts of different types of pharmaceutical packaging for medicines commercialized in pharmacies in Europe, aiming at identifying hotspots and opportunities for packaging improvement and providing recommendations. Methods A life cycle model was implemented for three types of pharmaceutical packaging (blisters, sachets, and bottles) most commonly sold in community pharmacies in Europe. The system boundary includes packaging production, assembly, and distribution to pharmacies. Twenty-three packaging alternatives, with different sizes and materials, have been analyzed. Distribution scenarios considering alternative production locations (Europe, Asia, the USA) and transport modes (truck, train, airplane, ship) have been assessed. The functional unit is the storage and delivery of medicines containing the same active pharmaceutical ingredient, dosage, and amount of medicines. Primary data were collected from the pharmaceutical sector. The life cycle impact assessment has been performed for five categories: global warming, abiotic depletion-fossil fuels, acidification, ozone depletion, and eutrophication. Results and discussion There is a high variation of impacts within the alternative packaging for the same medicine, being more significant for blisters (up to five times) than for bottles and sachets. Production of materials is the highest contributor. The use of aluminum presents very high impacts, particularly for acidification, while PVC has significant impacts for fossil fuel depletion. PVC is the forming film that presented the lowest environmental impacts, followed by PVC/PVDC and OPA/Alu/PVC. Truck transportation impacts are more significant for larger-size packaging, due to the amount of packaging transported being limited by volume rather than weight. Train and ship presented better environmental performance. Conclusions There is a great potential for ecodesign improvement in pharmaceutical packaging, particularly for blisters. There is a great potential for ecodesign improvement in pharmaceutical packaging, particularly for blisters, which should use PVC for the forming film and are preferable to sachets. Packaging with compact formats, avoiding empty spaces, and superfluous elements are recommended, which lead to a reduction of environmental impacts and production costs. Selecting means of transport with lower environmental impacts is highlighted, as the volume-limited capacity of vehicles is a critical hotspot for lightweight packaging. Lastly, recommendations are provided for the pharmaceutical packaging sector in Europe (and worldwide). The importance of LCA-based ecodesign is highlighted, providing directions for pharmaceutical stakeholders and future regulations.

Article
Purpose Companies meet hindrances and difficulties in adopting life cycle assessment (LCA) as a way to identify and assess the environmental aspects of their products and services. Collaborative approaches that are able to involve companies, researchers, trade associations, and other stakeholders can support the organizations in overcoming the LCA barriers by developing common resources. So, the research goal is to demonstrate how the developed collaborative approach enhances the adoption of LCA and product environmental footprint (PEF) in small and medium organizations. The paper presents the results achieved by 15 organizations, operating within five different supply chains, where the collaborative approach was tested. Method The research method we followed in our research is the “action research,” focused on the so called “engaged scholarship.” Action research is based on a strong cooperation between researchers and practitioners belonging to the organizations involved. It relies on extensive interaction in order to solve a specific problem and generate new knowledge. Results and discussion A cooperative approach was designed and proposed to five supply chains (foundry, furniture, two food chains, and catering services) and in particular to 15 Italian companies that adopted LCA and PEF to improve their environmental performance. Each supply chain tested and internalized the proposed collaborative approach: In partnership with trade associations and researchers, companies participated in training initiatives, contributed to the development of PEF Category Rules, measured the environmental footprint of their products, and adopted improvement actions. Thanks to the action-research experience, all the involved companies achieved environmental improvements such as energy saving and emissions reduction, which demonstrates how the collaborative approach to LCA is effective in terms of footprint reduction. Conclusion The research shows how the proposed collaborative approach can be effective for overcoming the lack of resources and knowledge in LCA adoption. The five supply chains, and 15 organizations involved, had the chance of experimenting “in field” how the LCA can improve both their competitiveness and their environmental performance. The research findings also contribute to the stakeholder engagement theory.

Article
Consumers increasingly demand information about the environmental impacts of their food. The French government is in the process of introducing environmental labelling for all food products. A scientific council was set up, and its main conclusions are presented in this article, through six questions: What environmental issues should be considered? What objective should be targeted? What data are needed, and for whom? What methods for assessing environmental impacts? Which environmental scores should be chosen? What label format should be proposed? By answering these questions and considering the context, the available data, the proposed methods and adjustments, and the knowledge of consumer perception of formats, the scientific council considers that a labelling scheme is feasible and relevant.

Article
Purpose In a service society, the assessment of climate-relevant environmental impacts of services is of increased importance. In the few Product Category Rules (PCRs) for cleaning services available to date, it is noticeable that employee mobility and service-related management are excluded from the assessment. This practice is critically questioned in the following study. The aim is to show that a calculation of the carbon footprint of services that integrates employee mobility and service-related management provides a better basis for finding ways to reduce their environmental impact. Methods Key figures on the CO2e emissions of services are examined in exemplary case studies using the example of cleaning, maintenance and reception with regard to the possible share of emissions caused by employee mobility and service-related management activities. For the case studies located in Germany, characteristic values of the equipment, operating materials or mobility used for the service are obtained from available Environmental Product Declarations (EPDs). In the absence of EPDs, a simplified estimate is made according to the VERUM method based on the proportion of materials in the product. The case studies compare the carbon footprint of a service by omitting and including employee mobility and service-related management. Results The analysed case studies show an impact share between 32 and 69% for employee mobility and between 10 and 26% for service-related management activities in an integrated carbon footprint of services. The emissions caused by employee mobility and service-related management therefore have a dimension that should not be neglected. Conclusions From these findings, the necessity is derived to include the emissions from the mobility of operational staff and service-related management in future PCRs for services in order to improve the comparability of services. Optimisation efforts of companies must also start at these points of the service organisation.

Article
Purpose With a contribution of 39% to greenhouse gas (GHG) emissions, reducing the environmental impacts of buildings plays an undisputed role in achieving climate goals. Therefore, the development of projects with a low carbon footprint is of crucial importance. Although several active and passive solutions as well as design strategies have been developed, identifying critical levers to minimise GHG emissions and the cost of future building projects is still a problem faced every day by designers. Methods Motivated by this knowledge gap in this study, we conducted a life cycle assessment (LCA) and life cycle cost analysis (LCCA) of a residential building situated in Austria. To identify the critical levers for reducing impacts and cost, 37 scenarios with three different advanced energetic standards are created. The scenarios with the various standards are developed through the combination of different construction materials, insulation materials and technical building equipment. In the eco-efficiency assessment (LCA and LCCA), a reference study period of 50 years is assumed. The life cycle of the building scenarios was analysed according to the European standard EN-15978. Results Results show that improving the energetic standard does not yield an overall cost savings potential. The additional construction cost (23%) for energy efficiency measures, including thermal insulation and change of technical building equipment, is higher than the reduction potential in operating cost over 50 years. On the other hand, the improvement of energetic standards allows a reduction of the environmental impacts by 25%. Conclusions To ensure a cost-optimal environmental improvement of buildings, it is crucial to conduct an eco-efficiency assessment during the design process of energy-efficient buildings. This study shows how improving the energetic standard of buildings can reduce environmental impacts with slightly increased life cycle cost.

Article
Purpose The impact of particulate matter (PM) formation on human health in Life Cycle Impact Assessment (LCIA) can be characterized through combining intake fractions with effect factors. However, although there are several characterization models used in different LCIA methods, most of them were not developed for the Brazilian context. This study aims to evaluate the existing models used in LCIA for characterizing PM impacts on human health with respect to their applicability for Brazil. Methods We review existing PM characterization models followed by a critical analysis regarding each model’s scope, scientific robustness, and applicability for Brazil, by applying the simple multi-attribute rating technique (SMART). Results and discussion The results show that the most recent models, with global coverage and availability of characterization factors (CFs) for Brazil, are the most appropriate. In addition, the highest-scoring models are able to connect with a wide range of goals and scopes that can be defined in Life Cycle Assessment case studies. Although the models of van Zelm et al. (2016), Fantke et al. (2017, 2019), and Oberschelp et al. (2020) are recommended for Brazil, important limitations have been observed. The van Zelm et al. (2016) model provides only country-level CFs and is not further regionalized. The Fantke et al. (2017, 2019) model does not currently provide CFs for PM precursors and is for urban factors limited to cities with more than 100,000 inhabitants. The Oberschelp et al. (2020) model does not currently provide data for indoor environments and uses background concentration data mainly applicable to the Northern Hemisphere. Conclusion Several models for evaluating PM impacts in LCIA are already available. Considering the identified limitations within these models, future work should aim to address these limitations and derive improved and more representative CFs for Brazil.

Article
Purpose Carbon emission from roads is an important contributor of a nation’s greenhouse gas emission that causes climate change. However, the existing life cycle assessment (LCA) analysis of road carbon emissions focus on project-level, ignoring regional differences. Significant challenges remain in developing regional road’s carbon emission mitigation strategies. This study estimates the quantity of carbon emissions from roads in China and calculated the regional equity of road carbon emissions. Methods An improved LCA approach, which considered the regional difference of raw materials’ carbon emissions, carbon emissions caused by traffic jam and road category, was applied to calculate the quantity of carbon emissions of roads. Sensitive analysis was conducted to find the key influential factors. Gini coefficient was used to calculate the equity degree of carbon emissions by roads based on the LCA results. The decomposition model of Gini coefficient is applied to analyze the causes of carbon emission differences. Results The total national carbon emissions by roads in 2019 increased by 2.2 times compared to 2009. Carbon emission from roads in the operation phase increased from 62% in 2009 to 83% in 2019. The functional unit for expressway in this study ranging from 1646 to 1794 t CO2e/km in 31 provinces. An estimated uncertainty of plus or minus 4% of the traffic flow allocation between expressway and other roads makes an increase of 38% or a decrease of 15% of the life cycle emission. The overall Gini coefficient of carbon emissions from roads in China is under the warning line of 0.4. Outer inequity between regions contributes 88.83% of the whole inequity and the most developed three regions contribute 66.23%. Conclusions Large quantity of road construction in the past in China makes the burden of carbon emission transfer from the construction phase to the operation phase. Regional differences of raw materials’ carbon emissions, traffic jam, and road hierarchy are important factors influencing the LCA-based estimation of road carbon emission. To improve the national equity degree of road carbon emission, quota allocation of road carbon emission rights between regions and cross-regional carbon emission reduction policies would help.

Article
Purpose Common octopus is the fishing species with highest economic revenue in Portugal, and its consumption per capita is very high. The majority of catches come from the small-scale fleet with pots and traps. The aims were to assess main environmental impacts of common octopus’ fishery with traps and pots in the Algarve region, where the most important fleet size and landings volume occurs, and to find if there are significant differences between both fishing gears. Methods The assessment includes standard LCA impact categories, fishery-specific impact categories, and quantification of macroplastics and microplastics emitted to the environment. The functional unit selected was 1 kg of octopus and the study was a ‘cradle to gate’ system. The scope included fishing operations until the product is landed at the harbour. Primary data was obtained by face-to-face questionnaires from 22 vessels, with an average of 1005 pots and 1211 traps per vessel, and 372 pots and 234 traps lost annually to the environment. Plastic pots have a concrete block and traps are a metal framed covered by plastic netting. Each trap or pot is connected to the main line at regular intervals. Unlike traps, pots do not need bait. Results and discussion Fuel contribution to global warming is very high and where the highest potential exists to lower down the carbon footprint. The fuel use intensity resulted in 0.9 L/kg of octopus. The bait used in traps is significant and raises further environmental costs related with fuel consumption. The use of traps represents more than two times the impacts found for pots in all the categories studied except ecotoxicity categories. Zinc use was the main contributor to ecotoxicity categories, but it has not been included in other fishery LCA studies. It was estimated that 12.2 g of plastics is lost to the environment per kg of octopus. The loss of macroplastics from fishing gears was the highest contributor. Conclusions The carbon footprint obtained was 3.1 kg CO 2 eq per kg of octopus, being lower compared to other seafood products, and less than half compared to octopus caught with trawling. Pots and traps are highly selective fishing gears, causing negligible disturbance to the seafloor. The stock is not assessed, but management measures exist and can be improved. A drawback exists related with gears lost to the environment.

Article
Purpose Plastics generate more than 500 tons of waste in Ecuador each year, according to statistics from 2016. Therefore, the Ecuadorian Congress has approved a law to ban single-use plastics to deal with their high volumes contaminating the environment. Furthermore, researchers and policymakers have been concerned about finding possible solutions to replace single-use plastics. Hence, the production of polylactic acid (PLA) in Ecuador and its environmental impact analysis and potential use as the replacement material for petroleum-based polymers is the aim of this study. Methods An environmental performance analysis is carried out for the potential production of polylactic acid (PLA) in Guayaquil, Ecuador. For this purpose, the life cycle assessment (LCA) methodology has been used. Therefore, the LCA was considered in three steps: production of PLA, transformation to film product, and end-of-life scenario. The LCA was performed to analyze the potential environmental impact of 1 m² PLA film production. The International Life Cycle Data System (ILCD) 2011 Midpoint + method, which exists in SimaPro software, was used for the impact analysis. Results and discussion The production of biodegradable PLA film causes a climate change impact of 0.85 kg CO2 eq for the established functional unit and several positive environmental impacts. Due to the natural raw material used for its production, the PLA production process significantly contributes to the impacts. The process contribution order was calculated starting with PLA production (74.32%), then electricity (20.41%), polyethylene glycol (PEG) (5.05%), and finally transport (0.21%). An increase in PLA production requires more land, machinery, fuel, and fertilizers. These increases mean higher environmental impacts. PLA production in Ecuador showed a 14% higher climate change indicator than its production in the USA. Optimization of the process could lower the indicator. The landfill scenario was the most pollutant, but recycling shows great promise as the option for end-of-life. Conclusion Despite being a bio-solution, all the parameters must be considered when analyzing a shift from plastics to PLA biopolymer. According to the sensitivity analysis, the production of PLA and its film product system had a good consistency when parameters like the amount of sugar needed is varied. According to the environmental score obtained, PLA production from sugar cane is the best option in its production in Ecuador.

Article
Purpose The primary objective of this study was to evaluate the environmental impact and financial cost of repairing surgical scissors. Methods We used life cycle assessment (LCA) and life cycle cost analysis to estimate environmental impacts and financial cost of repairing surgical scissors. The functional unit was one use of a reusable surgical scissor (manufactured in Germany and used in the UK), and three baseline scenarios were compared: no repair, onsite (hospital), and offsite (external contract) repair. This ‘cradle-to-grave’ analysis included raw material extraction, manufacture of scissors and materials within primary and secondary packaging, transportation, decontamination, repair (where relevant), and waste disposal. Primary activity data was sourced from the instrument manufacturer, supplier, and from UK repair centres (both onsite and offsite), whilst the Ecoinvent database was used as a secondary data source for the manufacture of scissors. The World ReCiPe Midpoint and Endpoint Hierarchist method (Version 1.1) was used for environmental impact assessment. Scenario analysis was used to evaluate the impact of altering different assumptions, including number of uses, reducing number of repairs, increasing distance to offsite repair centre, and alternative electricity sources and waste handling processes. Life cycle cost analysis was calculated based on purchase cost, and cost of decontamination, repair, and waste disposal. Results and discussion The carbon footprint of reusable scissors was 70 g CO 2 e per use, assuming scissors were used 40 times before replacement. This was reduced by 19% through use of offsite repair every 40 uses (57 g CO 2 e/scissor use), with small additional reductions associated with onsite repair (56 g CO 2 e/scissor use). Similar patterns of reduction were calculated for eighteen midpoint environmental impact categories (mean impact reduction of 30% for those repaired offsite relative to no repair) and also across three endpoint categories. Decontamination made the biggest contribution to the carbon footprint across all baseline scenarios (76% where no repair, 95–97% where repaired offsite and onsite respectively). Findings were robust to alternative scenario analyses. Life cycle cost was GBP £1.43 per use of reusable scissors, and when repaired either on- or offsite this decreased by 32% to GBP £0.97 per use. Conclusion Repairing surgical scissors rather than replacing them with a new pair can reduce environmental and financial cost. The extent to which repair may play a role in mitigating the environmental impact of other surgical instruments requires further research.

Article
Purpose An adequate matching between the nomenclature of elementary flows in life cycle inventory (LCI) databases and life cycle impact assessment (LCIA) methods is key for ensuring the proper application of life cycle assessment (LCA). However, the nomenclature of elementary flows lacks harmonization among the LCA community. This paper aims at defining mapping rules and discussing main challenges related to the process of systematically mapping LCI nomenclatures to LCIA methods and models addressing biodiversity impacts. Methods Eight LCIA methods and models addressing biodiversity loss are analyzed: five comprehensive LCIA methods (i.e., LC-IMPACT, Impact World + , Ecological Scarcity 2013, ReCiPe 2016, and Stepwise), one land use intensity-specific LCIA model; and two approaches adapting the GLOBIO model to LCIA. These models and methods are mapped to two LCI nomenclatures (ecoinvent v3.6 as implemented in Simapro and Environmental Footprint (EF) 3.0). A mapping tool was developed to support the process of (a) mapping elementary flows by name, Chemical Abstract Service number or available synonyms; (b) implementing specific mapping rules regarding compartment/sub-compartment, and substance name; (c) mapping elementary flows to manually defined proxies (e.g., synonyms, spelling corrections and similar substances); and (d) assigning characterization factors (CFs). The process entails analyzing a case study to identify uncharacterized elementary flows. Results and discussion We present a mapping of LCIA methods and models addressing impacts on biodiversity loss with specific LCI nomenclatures. Mapping rules are proposed for elementary flows regarding chemicals, carbon emissions, land use, water use, and particulate matter. Specific aspects to be considered in mapping elementary flows in LCIA and LCI nomenclatures are discussed. Main gaps in LCI nomenclatures are associated to toxicity and climate change impacts. The EF 3.0 was more aligned than ecoinvent 3.6 with the LCIA methods and models regarding elementary flows coverage and regionalization level. Analyzing uncharacterized flows revealed further coverage needs for “Chemical, organic” (between 19 and 20% uncharacterized flows), “Chemical, inorganic” (between 9 and 18% uncharacterized flows) and “Chemical, radioactive” (between 9 and 14% uncharacterized flows). Conclusions This paper contributes to the operationalization of LCIA methods and models addressing biodiversity impacts by proposing a systematic mapping process and rules for a better LCIA-LCI connection. Different development pathways of LCI (e.g., focused on substance name detail) and LCIA (e.g., towards improved regionalization level) have stretched the gap between both nomenclatures. Recommendations are provided identifying further efforts towards the harmonization of the nomenclature of elementary flows in the LCA community.

Article
Purpose The assessment of the economic feasibility of floating offshore wind farms (FOWFs) plays an important role in the future possible spreading of this challenging technology in the wind power industry. The use of specific economic analyses is fundamental to point out the potential of FOWFs and to sustain their technical value. Within this topic, the implementation of the FOWF life cycle cost model and producibility analysis in a geographic information system is developed, with the aim of carrying out a feasibility analysis at the territorial scale, for different types of floater. Moreover, a simplified model for a quick life cycle cost assessment is proposed and calibrated. Methods The available cost model is first validated comparing the costs of FOWFs based on different floaters (Semi-Submersible Platform—SSP, Spar Buoy—SB and Tension Leg Platform—TLP) with corresponding results available in the literature. Then, it is implemented in QGIS to be used for territorial-scale analyses and sensitivity analyses of the cost parameters. A feasibility analysis is developed through the main financial parameters. Finally, the results are then used to calibrate a simplified version of the cost model that depends on three main parameters, namely distance to shore, distance from the port of operation and bathymetry. Results and discussion The FOWF cost values are found to be in good agreement with those coming from analytical methods similar to the one from the authors. However, some discrepancies with those based on average costs are observed. Then, the results of the sensitivity analysis are presented as life cycle cost maps, giving an overall picture of the variation of the total cost of FOWF installations on a reference domain. The results show that among the three types of floaters considered here, the SSP proved to be the most promising one, giving lower costs than the SB and the TLP. Moreover, a good agreement between the results in terms of total cost of FOWFs calculated with the analytical and simplified models for SSPs, SBs and TLPs is observed. Finally, the feasibility analysis showed that the financial parameters are more influenced by the wind speed than by the cost of the farm. Conclusions The paper aims to provide guidance on how to carry out feasibility analyses of a specific site for FOWF installation, thus supporting decision-making procedures. The approach and the results presented here are meant for use in the early stage of the decision-making process, as a tool for the assessment of the economic feasibility of FOWFs installation.

Article
Purpose Coal mine overburden is a term typically used to refer to the waste rocks and the soil materials generated from the open cast method of coal extraction. Previous investigations have found that recycled aggregates from coal overburden are suitable as subballast material in railway trackbed. But no study has been reported yet that analyzes the environmental consequences of this option using the life cycle assessment (LCA) technique. To ensure sustainability, it is vital to examine the environmental consequences of alternatives which is performed in this study. Method The present study compares the environmental impacts of processed aggregates from coal mine overburden with that of natural subballast material. The study also investigates the environmental sustainability of using geocell-reinforced overburden aggregates (GOBA) in the subballast layer. The database used for this LCA study is Ecoinvent 3 database and the impact assessment method adopted is IMPACT 2002 + method. The effects on 15 midpoint indicators and four endpoint indicators along with the contribution of each of the processes involved in the production toward the categories are presented in this study. Results According to the findings, when compared to natural aggregates, processed aggregates from overburden lower the potential for climate change by 35% and the demand for non-renewable energy by 33%. Furthermore, the production of geocell-reinforced OB aggregates reduces the potential for climate change by 16%. Conclusions Based on the IMPACT 2002 + method used in this study, the use of OB aggregates in the track bed's subballast layer significantly lowers the negative effects on human health, climate change, ecosystem quality, and resources and reduces the impacts on all midpoint category indicators. Lastly, the obtained results can be a major support in advancing the resourceful management of coal overburden and the conservation of natural aggregate sources.

Article
Purpose This paper reviews the state-of-the art research in life cycle assessment (LCA) applied to buildings. It focuses on current research trends, and elaborates on gaps and directions for future research. Methods A systematic literature review was conducted to identify current research and applications of LCA in buildings. The proposed review methodology includes (i) identifying recent authoritative research publications using established search engines, (ii) screening and retaining relevant publications, and (iii) extracting relevant LCA applications for buildings and analyzing their underpinning research. Subsequently, several research gaps and limitations were identified, which have informed our proposed future research directions. Results and discussions This paper argues that humans can attenuate and positively control the impact of their buildings on the environment, and as such mitigate the effects of climate change. This can be achieved by a new generation of LCA methods and tools that are model based and continuously learn from real-time data, while informing effective operation and management strategies of buildings and districts. Therefore, the consideration of the time dimension in product system modeling is becoming essential to understand the resulting pollutant emissions and resource consumption. This time dimension is currently missing in life cycle inventory databases. A further combination of life cycle impact assessment (LCIA) models using time-dependent characterization factors can lead to more comprehensive and reliable LCA results. Conclusions and recommendations This paper promotes the concept of semantic-based dynamic (real-time) LCA, which addresses temporal and spatial variations in the local built and environmental ecosystem, and thus more effectively promotes a “cradle-to-grave-to-reincarnation” environmental sustainability capability. Furthermore, it is critical to leverage digital building resources (e.g., connected objects, semantic models, and artificial intelligence) to deliver accurate and reliable environmental assessments.

Article
Purpose In response to the public concerns on the performance regarding environmental conservation and energy saving, manufacturers have to perform environmental impact assessments for their products. Some eco-design tools have been introduced to support the development of greener products. However, most of them require decision-makers’ qualitative judgment during the evaluation processes. In this connection, this research aims to propose a practical approach that uses Cuckoo search and life cycle assessment (LCA) to support design decision-making from the environmental perspective in the initial design stage. Methods Aiming to develop a handy approach for evaluating the potential environmental impact during the initial design stage, the proposed approach combines Cuckoo search and LCA to determine the optimal design parameters by simultaneously considering multiple design constraints. A case application based on an electric kettle design is presented to demonstrate the applicability of the proposed approach. Results and discussion This approach provides a fast-track way to determine the optimal parameters for several key design decisions. The result is presented in a simple form with the corresponding environmental impact value, and thus, further interpretation of the results is not required. Conclusions/implications This approach offers an immediately applicable tool for the decision-makers to determine the key design parameters from the environmental perspective. A pilot case implementation on a simple electric kettle design is presented to showcase the applicability of the combined Cuckoo search and LCA approach. The proposed approach may provide a systematic way of evaluating multiple design combinations. The result obtained from the approach is reliable and able to support the decision-makers in selecting a suitable set of design parameters in view of lowering the potential environmental impact of the products.

Article
Purpose The social aspects of municipal solid waste management (MSWM) systems are underpinning their sustainability and effectiveness. The assessment of these systems from a life cycle perspective is widespread throughout environmental life cycle assessment (LCA), but few studies have used social life cycle assessment (S-LCA). The present study is an innovative review with the objective to analyse and describe the current level of development of S-LCA applications in MSWM, and to identify the main methodological challenges and best practices, aiming at recommending approaches to harmonise future S-LCA applications in MSWM. Materials and methods A systematic review of the literature found 36 relevant scientific articles. These were submitted to bibliometric and content analysis, which includes an analysis of how methodological aspects of the four phases of S-LCA were applied in comparison with best practice and existing guidelines. Results and discussion There was a predominance of case studies in developing countries (59%) and evaluation of the stages of collection/transportation, pre-processing (sorting) and landfilling (55%). There were more studies focusing on stakeholders, “workers” and “local communities” and in the impact subcategories “employment”, “working hours”, “health and safety/working conditions”, “community involvement/participation” and “health and safety/living conditions of community”. There was great variability in the application of the method (47% of the studies included methodological developments). However, the 39% based on UNEP guidelines were closer to a methodological consensus. Conclusion In general, studies need more detail and clarity in describing the methodological decisions used. Improvements are needed for issues that limit the S-LCA method, including the difficulties of covering the entire life cycle, relating impacts to the functional unit, standardizing impact assessment methods, addressing allocation and data quality issues and interpretation of results and their limitations. Improvements can be achieved by using participatory methods in the selection of categories, subcategories and impact indicators, as well as by clarifying the definition of a product system and detailing “cut-off criteria” of processes/organizations and the impact of these decisions on results.

Article
Purpose Transition to bioeconomy requires all actors and stakeholders to measure the impact of systems that use bioresources and technologies to provision society. There are however some challenges with integrating LCA into business development and management, which have important implications for bioeconomy. There have been many LCA studies published in the twenty-first century, but the question must be answered: how useful are these LCA studies to help understand and manage transition to sustainable bioeconomy? Method This research used a structured literature review to identify 83 bioeconomy LCA studies published from January 2006 to June 2021 (excluding bioenergy). The studies were analysed for compliance with the ISO 14044 standard, with specific reference to the goal, commissioning perspective, system boundary, function and functional unit, impact methods and categories. Results and discussions It was found that more than 85% of the studies reviewed failed to present the required goal statement and a description of the function of the system. Nearly 13% of the studies did not define the system boundary, and only 17% included a full life cycle including raw material extraction, production, use and end-of-life stages. The majority of the LCA studies surveyed from 2006 to 2021 were either (i) not in compliance with the ISO standards or (ii) space and style limitations of the publication process prevented competent practitioners from properly conveying their work. This suggests that the value and integrity of the literature are undermined by not rigorously addressing the first and most important stage of an LCA study. Conclusion When interpreting the results, a major shortcoming noted was that most studies did not consider the industrial symbiosis needed between feedstock, technology, primary products, side streams, downstream valorisation and long-term circularity in order to properly understand the transition pathways required. Bioeconomy technologies were imagined as displacers for feedstocks and processes to adapt business as usual, rather than as transformers of the system to a sustainable footing. Recommendation If LCA studies are going to provide meaningful information for actors and stakeholders to assess whether a system will be able to operate sustainably, studies should include a full, integrated system, standards should be adhered to and approaches should perhaps go beyond mere eco-efficiency, or doing less harm, as these are not necessarily indicative of sustainability. Historical bioeconomy LCA studies do not provide great insight into the transition to sustainable bioeconomy.

Article
Purpose An insufficient amount of available domestic water can lead to an increase in the occurrence of water-related diseases. No LCIA consensus has been reached on how to model the potential impacts on human health resulting from water use implying domestic water deprivation. Building on Boulay et al. (2011), this research work provides an updated and revisited characterization model and factors assessing the potential impact on human health induced along this impact pathway. Method This work consolidates the cause-effect chain linking water use to domestic impacts on human health. The revised fate factor aligns current water use assessment methods and includes information not only on the physical water scarcity but also on the level of population access to water in a region. Building on Boulay et al. (2011), the global effect factor is revised. The data source is updated, and a novel approach is developed estimating the domestic water deficit. Country-scale exposure factors are updated, building on Boulay et al. (2011)’s proposal to rely on the gross national income per capita as a proxy for a country’s capacity to adapt to water shortages. Results and discussion Compared to Boulay et al. (2011), the revised fate and exposure factors show lower values as a result of different methodological choices and of the overall increase of GNI per capita, respectively. The revised value of the effect factor is equal to 3.13E-3DALY/m3 which compares to the value of 3.11E-3 in Boulay et al. (2011). Revised characterization factors (CF) range from 0 DALY/m3 (the potential impact on human health due to water use is null with respect to domestic water deprivation) to 3.13E-3 DALY/m3. The distribution of the new CFs shows an order of magnitude decrease compared to the previous model. These CFs assess the consequences on human health induced by water use leading to short-term water deprivation. Conclusion and recommendations This research work helps to better account for the impacts of water use at the endpoint level. However, it underlines significant limitations in the current calculation of the effect factor, in particular regarding current quantification of domestic water deprivation. These shortcomings prevent the model from considering a difference in vulnerability to health damages from the deprivation of 1 m³ of domestic water. This research work argues for additional research efforts aimed at developing an alternative calculation method for this factor.

Article
Purpose Metal ore smelters have significant environmental footprints due to very high energy consumption and the resulting large quantities of waste heat. The industry recognizes, therefore, the need for implementation of changes to improve process economics by reducing primary energy consumption through recovery and repurposing of waste heat. However, when deciding the merit of a process modification, it should not only be based on economic gains (which have previously been highlighted), but also on environmental impacts. For the latter, life cycle assessment (LCA) is a well-established and useful tool. But across the mineral processing industry, LCA is not commonly incorporated into decision-making processes. Methods We have investigated the environmental gains from introducing low-grade heat recovery and repurposing within a smelters’ sulphuric acid plant. An LCA model was developed to first assess the environmental impact of existing sulphuric acid making processes across four standard potentials (global warming, acidification, eutrophication, and relative human toxicity). The model was then used to examine the potential of installing heat pumps to capture waste heat from water cooling towers associated with sulphuric acid production and repurposing it to replace existing on-site electric heaters. Results and discussion The study found that replacing electric heaters made significant improvements in a range of environmental impacts. The results of the model show a potential 13% reduction in electricity consumption, with a 53% reduction from the mist precipitators in global warming, acidification, eutrophication, and relative human toxicity potential. Conclusion The LCA comparison showed a potential 13% reduction in overall electricity consumption through the addition of low-grade heat capture using heat pumps, as well as a 5% reduction in heat load on the cooling towers. Together, this would lead to a 21% reduction in carbon dioxide equivalent emissions from the mist precipitators and cooling towers, as well as acidification, eutrophication, and relative human toxicity potential.

Article
Purpose Life cycle assessment (LCA) is a widely used method for the evaluation of buildings’ environmental impacts, but these analyses contain high levels of uncertainty. Decarbonization of electricity production is key to reach climate goals, influencing all sectors including construction The objective of this paper is to study the sensitivity of the environmentally optimum building design solution to a changing electricity mix to assist decision-making. Methods In this paper, multi-objective optimization was applied to minimize the life cycle global warming potential and life cycle costs of a building at the same time, using dynamic energy simulation and LCA. The variables include building envelope parameters such as window ratio, insulation type and thickness in a typical new multi-family apartment building heated with a heat pump. A static, largely fossil-based electricity mix and a dynamic, gradually decarbonizing alternative are considered, as well as two electricity price increase scenarios. New metrics have been introduced to explore the results and describe the Pareto-optimal solutions, for example the improvement potential to contextualize the achievements through the optimization. Results and discussion The results show that, with the current electricity mix, building envelope optimization can improve the design by 18% on average in terms of the life cycle greenhouse gas emissions compared to typical new designs and by 10% with a dynamic mix in Hungary. With today’s static electricity mix, the optimization proved that the minimum energy efficiency requirements in force are close to cost optimality. However, from an environmental point of view, much higher insulation thicknesses have been shown as justified (U-values of less than 0.1 W/m²K). Conclusions Optimization of building design based on LCA is still not widely applied and the effect of a decarbonizing electricity mix on the optimum has not been studied before. The results of the paper demonstrate the importance of this question. Optimal solutions are different depending on the applied mix but an energy-efficient building envelope remains important: today’s cost-optimal building envelope proves to be both cost- and environmentally optimal in the long run.

Article
Purpose The main purpose of this S-LCA case study is to analyse social impacts of the use phase of mobility services is a holistic way, taking into account positive as well as negative impacts. The use phase plays an important role for the assessment of services, which is why this study exclusively focuses on the use phase assessment. That way, this study aims to contribute to answer the question whether mobility services can improve quality of life in cities. Methods For the analysis, seven different mobility options were chosen in the city of Berlin, Germany, including free-floating car sharing, e-scooter sharing, S-Bahn, subway, tram, bus and the car in private ownership. For the analysis, five stakeholder groups that are outlined in the S-LCA Guidelines (UNEP 2020) were taken into account: Local Community, Consumer, Worker, Value Chain Actors and Society. For a detailed analysis of all relevant aspects, 37 indicators were analysed, out of which 23 are quantitative and 14 are qualitative. For data collection, several different data sources were used, including publicly available data e.g. from statistics as well as own data from interviews. Results and discussion For comparability, all results are displayed on a 5-point scale from − 2 to + 2, in line with the Handbook (Goedkoop et al. 2018) and the S-LCA Guidelines (UNEP 2020). For some indicators, the results of the case study are as expected, for example regarding impacts on air quality. For other indicators, however, the results are specific for the analysed mobility services in Berlin and therefore give new insights and reveal new aspects, as for example in the case of job creation for the local community. The main challenge of this S-LCA case study was data availability and data quality, which is why assumptions and simplifications had to be made, especially regarding space occupancy and the allocation of common infrastructure. Conclusions This S-LCA case study provides a holistic assessment of the use phase of mobility services, taking into account five stakeholder categories and their respective social impacts. The study illustrates specific results for the city of Berlin, showing positive as well as negative social impacts of mobility services and outlines a procedure for further studies. That way, this case study contributes to answer the overlying question whether mobility services can improve quality of life in cities.

Article
Purpose Plastic pervades now almost every aspect of our daily lives, but this prosperity has led to an increasing amount of plastic debris, which is now widespread in the oceans and represents a serious threat to biota. However, there is a general lack of consideration regarding marine plastic impacts in life cycle assessment (LCA). This paper presents a preliminary approach to facilitate the characterization of chemical impacts related to marine plastic within the LCA framework. Methods A literature review was carried out first to summarize the current state of research on the impact assessment of marine plastic. In recent years, efforts have been made to develop LCA-compliant indicators and models that address the impact of marine littering, entanglement, and ingestion. The toxicity of plastic additives to marine biota is currently a less understood impact pathway and also the focus of this study. Relevant ecotoxicity data were collected from scientific literature for a subsequent additive-specific effect factor (EF) development, which was conducted based on the USEtox approach. Extrapolation factors used for the data conversion were also extracted from reliable sources. Results and discussion EFs were calculated for six commonly used additives to quantify their toxicity impacts on aquatic species. Triclosan shows an extremely high level of toxicity, while bisphenol A and bisphenol F are considered less toxic according to the results. Apart from additive-specific EFs, a generic EF was also generated, along with the species sensitivity distribution (SSD) illustrating the gathered data used to calculate this EF. Further ecotoxicity data are expected to expand the coverage of additives and species for deriving more robust EFs. In addition, a better understanding of the interactive effect between polymers and additives needs to be developed. Conclusions This preliminary work provides a first step towards including the impact of plastic-associated chemicals in LCA. Although the toxicity of different additives to aquatic biota may vary significantly, it is recommended to consider additives within the impact assessment of marine plastic. The generic EF can be used, together with a future EF for adsorbed environmental pollutants, to fill a gap in the characterization of plastic-related impacts in LCA.

Article
Purpose Organic agriculture (OA) has gained widespread popularity due to its view as a more sustainable method of farming. Yet OA and conventional agriculture (CA) can be found to have similar or varying environmental performance using tools such as life cycle assessment (LCA). However, the current state of LCA does not accurately reflect the effects of OA; thus the aim of the present study was to identify gaps in the inventory stage and suggest improvements. Methods This article presents for the first time a critical analysis of the life cycle inventory (LCI) of state-of-the-art organic crop LCIs from current and recommended LCA databases ecoinvent and AGRIBALYSE®. The effects of these limitations on LCA results were analyzed and detailed ways to improve upon them were proposed. Results and discussion Through this analysis, unrepresentative plant protection product (PPP) manufacturing and organic fertilizer treatment inventories were found to be the main limitations in background processes, due to either the lack of available usage statistics, exclusion from the study, or use of unrepresentative proxies. Many organic crop LCIs used synthetic pesticide or mineral fertilizer proxies, which may indirectly contain OA prohibited chemicals. The effect of using these proxies can contribute between 4–78% to resource and energy-related impact categories. In a foreground analysis, the fertilizer and PPP emission models utilized by ecoinvent and AGRIBALYSE® were not well adapted to organic-authorized inputs and used simplified modeling assumptions. These critical aspects can be transferred to respective LCAs that use this data, potentially yielding unrepresentative results for relevant categories. To improve accuracy and to contribute novel data to the scientific community, new manufacturing LCIs were created for a few of the missing PPPs, as well as recommendations for fertilizer treatment LCIs and more precise emission models for PPPs and fertilizers. Conclusions The findings in the present article add much needed transparency regarding the limitations of available OA LCIs, offers guidance on how to make OA LCIs more representative, allow for more accurate comparisons between conventional and OA, and help practitioners to better adapt LCA methodology to OA systems.

Article
Purpose The EU environmental footprint (EF) is a life cycle assessment (LCA)-based method which aims at assessing the environmental impacts of products and organisations through 16 midpoint impact categories, among which three address toxicity-related impacts. This paper presents the principles underpinning the calculation of the set of characterisation factors (CFs) for the toxicity-related impact categories in the EF version 3.0: freshwater ecotoxicity (ECOTOX), human toxicity cancer (HTOX_c) and human toxicity non-cancer (HTOX_nc). Methods In order to respond to the issues that emerged during the EF pilot phase, the input data and the calculation principles of the USEtox® model were updated. In particular, (i) robustness factors (RFs) were introduced to reduce the dominance of metals and to balance the lackness of a robust fate modelling for non-organic compounds in USEtox®; (ii) high-quality data were selected from databases of EU agencies (European Chemicals Agency and European Food Safety Authority) to guarantee the transparency and the reliability of input data; and (iii) a new approach based on HC20 (hazard concentration killing 20% of the exposed population) was implemented to derive freshwater ecotoxicity effect factors (EfF). Results and discussion The new approach increased the number of characterised chemicals in the three impact categories: ECOTOX (6038 chemicals, + 140%), HTOX_c (1024 chemicals, + 70%) and HTOX_nc (3317 chemicals, + 660%). Moreover, specific derivation principles were defined for assigning CFs also to relevant groups of chemicals (e.g. polycyclic aromatic hydrocarbons), and specific strategies were implemented to better align LCA toxicity data with data used for risk assessment purposes. Conclusions The new set of CFs was calculated to ensure a broader coverage of characterised chemicals and to overcome some limitations of the USEtox® model identified during the environmental footprint pilot phase.

Article
Purpose Current field emission modelling and toxicity characterisation of pesticides suffer from several shortcomings like mismatches between LCI databases and LCIA methods, missing characterisation factors, missing environmental compartments, and environmental impact pathways. The OLCA-Pest project was implemented to address these aspects and to operationalise the assessment of pesticides in LCA. Based on this effort, we propose an approach to integrate pesticide emissions into LCI databases. Methods The PestLCI Consensus Model has been developed in order to estimate emission fractions to different environmental compartments. The initial distribution fractions should be linked to the compartments air, agricultural soil, natural soil, and freshwater. Emissions to off-field surfaces are hereby distributed between agricultural soil, natural soil, and freshwater by using surface cover data. Deposition on the crop surface should be recorded in an emission compartment crop with 13 sub-compartments for crop archetypes for both food and non-food uses. Default emission fractions are provided to calculate the emission fractions for different pesticide application scenarios. Results and discussion A sensitivity analysis shows the effects of the application technique, drift reduction, crop and development stage, field width, and buffer zone on the initial distribution fractions of field-applied pesticides. Recommendations are given for the implementation of a set of default initial distribution fractions into LCI databases, for the organisation of metadata, and for the modelling of pesticide residues in food along the supply chain (processing, storage). Priorities for further research are: improving the modelling of pesticide secondary emissions, further extending emission modeling (e.g. additional application techniques, including cover crops), considering metal-based pesticides in emission models, and systematically assessing human health impacts associated with pesticide residues in food crops. Conclusions The proposed approach allows to preserve the mass balance of the pesticide emitted after application, to make a consistent assessment of ecotoxicity and human toxicity, to define a clear and consistent interface between the LCI and LCIA phases, to estimate initial emission distribution fractions based on existing data, to document metadata transparently and efficiently within crop datasets, and to model the removal of pesticide residues in food during processing.

Article
Purpose Overfishing has been a global challenge for several decades with severe impacts on biodiversity and ecosystem services. Several approaches for assessing overfishing in life cycle impact assessment exist, but do not consider scarcity in line with current policy and science-based targets. Furthermore, comparisons of results with other impact categories, e.g., climate change, are not possible with existing methods. Therefore, five approaches to assess overfishing based on the distance-to-target approach are introduced. Method Three global species-specific approaches (stock in the sea, target pressure, and fish manager) and two regional midpoint approaches were developed. For the stock in the sea, the weighting factor was derived as the relation of available biomass of the considered species to biomass at sustainable limits. Within the target pressure, the current pressure on fish stocks is set to the maximal sustainable pressure. For the fish manager, the catch is set in relation to the maximum sustainable yield. The catch is used for normalization in all three approaches. The two regional midpoint approaches consider production and consumption-based catch of fish stocks in relation to the fully fished share. The overfishing indicator based on pressure on fish stocks serves as the characterization factor. Normalization occurs with the characterized catch. Results and discussion To demonstrate the applicability of the approaches, a three-level case study was derived: (i) determining ecofactors for ten specific fish species in specific oceans; (ii) deriving ecopoints for production of fish meal and oil in Europe; (iii) comparison of fish oil with rapeseed oil for the categories overfishing, climate change, land use, and marine eutrophication. The highest ecofactors for the global approaches are characterized by high normalization and weighting factors. For the regional approaches, high overfishing characterization factors determine the result. The species contribution increases with rising amounts. Main challenges are data collection and interpretation which limit the overall applicability. The sensitivity analysis shows that the overall results vary significantly depending on the composition of the fish oil and meal. Conclusions It was shown that four of the five approaches are able to account for overfishing. However, only the production-based regional midpoint approach allows for comparison with other impact categories and is, therefore, most suitable for integration into life cycle assessment. The developed approaches can be used for a more comprehensive assessment of the environmental impacts of different diets as well as aquaculture feed solutions.

Article
Purpose The olive oil sector in Italy has a significant socio-economic, environmental, and cultural relevance. However, the environmental impacts of production and consumption models are considerable, mainly due to the demand for large quantities of resources (fuels, chemicals) and to the environmental impacts of residues’ disposal. Due to the scarcity of resources and climate change concerns, circular economy principles based on industrial ecology concepts are emerging. In this paper, the principles of circular economy were specifically applied to the olive oil supply chain, to improve the environmental sustainability of the sector. Methods The production chain of extra virgin olive oil was analyzed using the Life Cycle Assessment method, based on primary data from an oil farm and mill in Southern Italy. The environmental impacts were evaluated through the SimaPro software and the ReCiPe 2016 Mid-point (H) Impact Assessment Method, with reference to the functional unit of 1-L bottle of extra virgin olive oil. Some circular improvement options were investigated, comparing the impacts generated by (i) extra virgin olive oil linear production without valorization of by-products, (ii) extra virgin olive oil linear production with allocation of total impacts to co-products, and (iii) two circular production systems, incorporating improvements such as replacement of diesel with biodiesel and of electricity from the national grid with energy recovered from residues. Results and discussion The environmental impacts of the business-as-usual production pattern were identified for possible improvements. In all phases of the production chain of organic extra virgin olive oil, the most affected impact categories were human carcinogenic toxicity, marine ecotoxicity, and terrestrial ecotoxicity. As expected, the major contributions to almost all the analyzed impact categories were determined by the agricultural phase (92.65%), followed by the bottling phase (7.13%) and the oil extraction phase (0.22%). The valorization of by-products was considered by widening the system boundaries to ensure the environmental sustainability by developing circular patterns that feedback waste materials to upstream steps of the same process. The environmental impacts resulted lower in almost all the impact categories, with the major benefits gained in the global warming and fossil depletion impact categories. Conclusions The analysis proved that the reuse of pomace, prunings, and exhausted cooking oil initially considered as waste can bring benefits from an environmental point of view to the larger scale of the economy, by replacing fossil fuels, as well as to the olive oil chain itself, by providing the needed energy for production.

Article
Purpose The implementation of sustainability and circular economy (CE) models in agri-food production can promote resource efficiency, reduce environmental burdens, and ensure improved and socially responsible systems. In this context, indicators for the measurement of sustainability play a crucial role. Indicators can measure CE strategies aimed to preserve functions, products, components, materials, or embodied energy. Although there is broad literature describing sustainability and CE indicators, no study offers such a comprehensive framework of indicators for measuring sustainability and CE in the agri-food sector. Methods Starting from this central research gap, a systematic literature review has been developed to measure the sustainability in the agri-food sector and, based on these findings, to understand how indicators are used and for which specific purposes. Results The analysis of the results allowed us to classify the sample of articles in three main clusters (“Assessment-LCA,” “Best practice,” and “Decision-making”) and has shown increasing attention to the three pillars of sustainability (triple bottom line). In this context, an integrated approach of indicators (environmental, social, and economic) offers the best solution to ensure an easier transition to sustainability. Conclusions The sample analysis facilitated the identification of new categories of impact that deserve attention, such as the cooperation among stakeholders in the supply chain and eco-innovation.

Article
Purpose The characterization of land use impacts in life cycle assessment (LCA) requires a constant compromise between highly specific impacts models and coarse geographical scales available in life cycle inventory, where most information is provided at country level as the highest degree of geographical specificity. The derivation of country-specific characterization factors is usually done estimating impacts with the use of land cover and potential natural vegetation maps, assuming the most predominant biome per country as representative. This study explores the use of land system archetypes to derive country-specific characterization factors for land use-related soil erosion impacts that can better represent intra-national variations, while accounting for several biogeographical and socioeconomic differences. Methods Land use-specific characterization factors were derived as the potentially enhanced soil erosion rate, using the soil erosion rates of each archetype as a reference state, and correction factors to reflect the relative increase or decrease in soil erosion rates associated with each of the eight land use types assessed: forest, permanent crops, grassland, farmland, fallow ground, moorland, urban/industrial, and mining/landfill. Country-specific characterization factors for land use erosion impacts of occupation (in ton/(m²·year)) were calculated by taking into account the land system archetypes present in each country, the land use-specific characterization factors, and the likelihood of each land use type occurring across archetypes (based on rule of thumb expert estimates). The country-specific characterization factors were produced specifically for occupation impacts for each of the eight land use types, and covering 263 countries and territories/dependencies. Results and discussion The resulting 2,104 country-specific characterization factors displayed in average a considerably greater variation in comparison with characterization factors produced when only the most predominant archetype per country is assumed as representative per country. The results indicate that world generic values might underestimate up to 10 times the degree of impacts associated with land use types such as permanent crops, fallow ground, mining, and landfill. The use of land system archetypes presents a viable approach to derive country-specific characterization factors while taking into account key intra-national variations, as well as biogeographical and socioeconomic factors.

Article
Purpose Uncertainty and variability need to be taken into account in life cycle assessment (LCA) studies to make robust decisions. We introduce a novel approach in LCA that allows to decide if either uncertainty or variability is dominating in the results: two-dimensional Monte Carlo simulations (2DMC). We aim to do so in a pedagogical and transparent way, allowing interested readers to fully grasp all technical details for their own potential use in future studies. Methods In 2DMC, an approach from quantitative risk assessment, the model parameters are divided into four categories: deterministic, variable, uncertain, and uncertain ánd variable; and appropriate distributions are selected. These distributions are sampled separately, so they can be assessed separately in the output as well. Firstly, the approach was translated to the LCA context with an illustrative proof of concept model, freely available on our website. Further, two variants of the post-harvest apple chain in Belgium (bulk versus pre-packed) are worked out as a real life comparative LCA case study. This real-life case study is also analyzed in a classical, deterministic way and by performing a more often used one-dimensional Monte Carlo simulation (1DMC), allowing a comparison with the 2DMC results and associated interpretations. Results and discussion Deterministic results do not reflect the complexity of reality. 1DMC results provide an indication on the robustness and conclusiveness of the result of a comparative LCA, but do not provide a way to guide further decisions. 2DMC results do provide this as results typically belong to one out of three possibilities. Firstly, the 2DMC results may confirm the result of the deterministic results. Secondly, the 2DMC curves may show proof that the two products are equivalent when it comes to environmental impact. One may then decide to analyze the variability causes further or that other reflections, like cost, should be considered as well. Thirdly, the 2DMC curves may indicate that more detailed and accurate information is needed to come to conclusive results. Conclusions 1DMC results give a first indication on the need for a 2DMC analysis. If that is the case, 2DMC can be used in a comparative LCA to take uncertainty and variability separately into account. 2DMC results can guide decisions to obtain more conclusive results. We recommend to consider a 2DMC analysis when comparing two products or processes if needed, hereto, our proof of concept model fully documented available online may be a starting point.

Article
Purpose Composites consist of at least two merged materials. Separation of these components for recycling is typically an energy-intensive process with potentially significant impacts on the components’ quality. The purpose of this article is to suggest how allocation for recycling of products manufactured from composites can be handled in life cycle assessment to accommodate for the recycling process and associated quality degradations of the different composite components, as well as to describe the challenges involved. Method Three prominent recycling allocation approaches were selected from the literature: the cut-off approach, the end-of-life recycling approach with quality-adjusted substitution, and the circular footprint formula. The allocation approaches were adapted to accommodate for allocation of impacts by conceptualizing the composite material recycling as a separation process with subsequent recycling of the recovered components, allowing for separate modeling of the quality changes in each individual component. The adapted allocation approaches were then applied in a case study assessing the cradle-to-grave climate impact and energy use of a fictitious product made from a composite material that in the end of life is recycled through grinding, pyrolysis, or by means of supercritical water treatment. Finally, the experiences and results from applying the allocation approaches were analyzed with regard to what incentives they provide and what challenges they come with. Results and discussion Using the approach of modeling the composite as at least two separate materials rather than one helped to clarify the incentives provided by each allocation approach. When the product is produced using primary materials, the cut-off approach gives no incentive to recycle, and the end-of-life recycling approach and the circular footprint formula give incentives to recycle and recover materials of high quality. Each of the allocation approaches come with inherent challenges, especially when knowledge is limited regarding future systems as in prospective studies. This challenge is most evident for the circular footprint formula, for example, with regard to the supply and demand balance. Conclusions We recommend modeling the composite materials in products as separate, individual materials. This proved useful for capturing changes in quality, trade-offs between recovering high quality materials and the environmental impact of the recycling system, and the incentives the different approaches provide. The cut-off and end-of-life approaches can both be used in prospective studies, whereas the circular footprint formula should be avoided as a third approach when no market for secondary material is established.

Article
Purpose Life Cycle Assessment (LCA) is the process of systematically assessing impacts when there is an interaction between the environment and human activity. Machine learning (ML) with LCA methods can help contribute greatly to reducing impacts. The sheer number of input parameters and their uncertainties that contribute to the full life cycle make a broader application of ML complex and difficult to achieve. Hence a systems engineering approach should be taken to apply ML in isolation to aspects of the LCA. This study addresses the challenge of leveraging ML methods to deliver LCA solutions. The overarching hypothesis is that: LCA underpinned by ML methods and informed by dynamic data paves the way to more accurate LCA while supporting life cycle decision making. Methods In this study, previous research on ML for LCA were considered, and a literature review was undertaken. Results The results showed that ML can be a useful tool in certain aspects of the LCA. ML methods were shown to be applied efficiently in optimization scenarios in LCA. Finally, ML methods were integrated as part of existing inventory databases to streamline the LCA across many use cases. Conclusions The conclusions of this article summarise the characteristics of existing literature and provide suggestions for future work in limitations and gaps which were found in the literature.

Article
Purpose Products made of plastic often appear to have lower environmental impacts than alternatives. However, present life cycle assessments (LCA) do not consider possible risks caused by the emission of plastics into the environment. Following the precautionary principle, we propose characterization factors (CFs) for plastic emissions allowing to calculate impacts of plastic pollution measured in plastic pollution equivalents, based on plastics’ residence time in the environment. Methods and materials The method addresses the definition and quantification of plastic emissions in LCA and estimates their fate in the environment based on their persistence. According to our approach, the fate is mainly influenced by the environmental compartment the plastic is initially emitted to, its redistribution to other compartments, and its degradation speed. The latter depends on the polymer type’s specific surface degradation rate (SSDR), the emission’s shape, and its characteristic length. The SSDRs are derived from an extensive literature review. Since the data quality of the SSDR and redistribution rates varies, an uncertainty assessment is carried out based on the pedigree matrix approach. To quantify the fate factor (FF), we calculate the area below the degradation curve of an emission and call it residence time $${\tau }_{R}$$ τ R . Results and discussion The results of our research include degradation measurements (SSDRs) retrieved from literature, a surface-driven degradation model, redistribution patterns, FFs based on the residence time, and an uncertainty analysis of the suggested FFs. Depending on the applied time horizon, the values of the FFs range from near zero to values greater than 1000 for different polymer types, size classes, shapes, and initial compartments. Based on the comparison of the compartment-specific FFs with the total compartment-weighted FFs, the polymer types can be grouped into six clusters. The proposed FFs can be used as CFs which can be further developed by integrating the probability of the exposure of humans or organisms to the plastic emission (exposure factor) and for the impacts of plastics on species (effect factor). Conclusions The proposed methodology is intended to support (plastic) product designers, for example, regarding materials’ choice, and can serve as a first proxy to estimate potential risks caused by plastic emissions. Besides, the FFs can be used to develop new CFs, which can be linked to one or more existing impact categories, such as human toxicity or ecotoxicity, or new impact categories addressing, for example, potential risks caused by entanglement.

Article
Purpose The environmental impacts of breeding industries have been broadly studied and compared. However, environmental research on the rex rabbit breeding industry is scarce. The aim of this study was to evaluate the environmental impacts of two rex rabbit industry chains and verify which one has better environmental benefits, provide a scientific reference for the construction of a circular industry chain, and promote sustainable development of rex rabbit breeding and related industries. Methods Two different rex rabbit industry chains were considered: scenario 1 (a traditional industry chain, including feed cultivation, feed processing, rex rabbit breeding, and slaughtering stages); and scenario 2 (a circular industry chain, including feed cultivation, feed processing, rex rabbit breeding, slaughtering, manure treatment, and biogas power generation stages). A comparative study was performed using the life cycle assessment (LCA) methodology. The functional unit of this study was an average rabbit during 140 days of breeding. A transparent cradle-to-gate life cycle inventory of the two scenarios was provided through the field investigation of a rex rabbit enterprise in China, and SimaPro8.0.4 software was used to conduct the comparative LCA. The CML 2001-Nov.2010 method was used for characterization and normalization of the environmental impacts. Results and Discussion The environmental performance of S2 was better than that of S1 with a significant reduction in each impact category, except for acidification potential (AP). Terrestric ecotoxicity potential (TETP) and freshwater aquatic ecotoxicity potential (FAETP) were the primary environmental impact categories for S1, mainly because of electricity and fertilizer consumption. TETP and FAETP of S2, when compared with S1, were reduced by 93.7% and 91.6%, respectively. AP was the primary environmental impact category for S2. The largest contributor to each impact category was found in the feed cultivation stage; however, most of the impact categories of the feed cultivation stage were reduced in S2 when compared with S1, mainly because of the extension of the industry chain and reuse of byproducts of the manure treatment stage. Conclusions Comparative LCA of the two scenarios confirmed the environmental feasibility and benefits of the circular rex rabbit industry chain. By establishing the circular industry chain instead of the traditional industry chain and increasing the waste reuse and recycling to generate clean energy and reduce the consumption of chemical fertilizers, we can not only reduce the overall environmental impacts but also increase the environmental benefits of the rex rabbit industry chain.

Article
Purpose Increased accumulation of fossil-based polymer packaging films on land and ocean surfaces poses major environmental challenges to our ecosystem. Developing alternative packaging films with no or minimal environmental burdens is critically important. Cellulose nanofibril (CNF)-reinforced chitosan biopolymer composites are the most promising bio-based alternatives for packaging applications due to their biodegradable, biocompatible, and antimicrobial properties. This study evaluates the life cycle environmental impacts of chitosan-CNF composite films to identify the environmental hotspots that can be eliminated during large-scale production. Methods A cradle-to-gate life cycle assessment is conducted to evaluate the environmental impacts of citric acid crosslinked chitosan-CNF composite films that can be used for packaging applications. The main manufacturing operations include (i) production of chitosan from shrimp shell waste, (ii) CNF production from forest biomass, and (iii) production of citric acid crosslinked composite films by the solvent-casting method. Life cycle inventory data are obtained from published literature and laboratory experiments. The environmental impacts are evaluated by US EPA’s TRACI 2.1 impact assessment method. The effects of key process parameters on the environmental impacts of composite films are also evaluated. Results and discussion The global warming potential (GWP) of manufacturing chitosan-CNF composite films is about 3.91 kg CO2 eq./kg of the film, which is marginally lower than that of the fossil-based low-density polyethylene (LDPE) and bio-based poly(lactic acid) (PLA) films. The film casting sub-process in the composite film production contributes up to 90% of the total CO2 emissions. The amount of sodium hydroxide used in the deproteination of shrimp shells is the most sensitive factor in all impact categories. The scenario analysis shows the increase in the CNF loading rate to improve the mechanical and barrier properties does not substantially increase the global warming potential (GWP) and other environmental impacts. Conclusion A cradle-to-gate life cycle assessment of the chitosan-CNF composite film has demonstrated that the overall environmental impacts are comparable or lower than that of fossil-based polymers and other biopolymers considered in the flexible packaging applications. The development of renewable energy-based film dryers and environmentally benign methods to extract chitosan from shrimp shell waste can further reduce the GWP of composite films. When the end of life of fossil-based polymers is considered, the biodegradable nature of chitosan-CNF composite can be an environmentally attractive film for packaging applications.

Article
Purpose We observe a methodological gap for assessing impacts within the Area of Protection (AoP) Natural Resources in LCA with regard to concerns about the accessibility to raw materials. Adding criticality considerations as a complement to environmental LCA addresses abiotic resources accessibility. We present a study that integrates and applies an improved GeoPolRisk midpoint and the published GeoPolEndpoint methods as valuable enhancements to the current pool of available impact methods in LCA. Methods GeoPolEndpoint, an extension of the GeoPolRisk method, was designed to quantify the impacts of the use of raw materials from a criticality perspective at the endpoint level. We present an integrated characterization model including an improved midpoint method, which truly takes into account the mass flow extracted for a product, to operationalize the use of these methods at both midpoint and endpoint level within LCIA. We study the impacts of four relevant metals (Al, Co, Cu, and Ni) in the life cycle of lithium-ion batteries (LIB) for the years 2015 to 2017 from the perspective of the EU. Inventory data are based on previously published studies with a detailed bill of materials for two types of LIB. As part of an integrated assessment, results at midpoint and endpoint levels were compared to other impact categories within the context of an attributional LCA. Results and discussion From the analyzed raw materials, copper and nickel contribute significantly to environmental impacts; however, cobalt has a high geopolitical supply risk indicator and higher contribution at the GeoPolEndpoint despite its relatively low contribution to the environmental footprint of LIB. Results show the importance of specific raw materials present in small quantities, but with a high contribution when applying a criticality lens as a complement to LCA. The new method has the potential to be operationalized in LCA studies and to provide new insights on supply risk during product development. Conclusions Impacts of the use of raw materials deemed critical are not only restricted to an environmental dimension; we can model socio-economic impacts through a criticality perspective. The GeoPolRisk and GeoPolEndpoint methods allow the integration of a supply risk perspective into LCA studies. With the introduction and development of new technologies, the evaluation of raw material criticality in LCA becomes an important complement to environmental indicators. This case study provides a baseline for future applications of the method to products and technologies that require the use of critical raw materials throughout their life cycle.

Top-cited authors
• Aalborg University
• Paul Scherrer Institut
• Leiden University