Development of regional characterization factors for aquatic eutrophication

Background, aim, and scope  

Life cycle assessment (LCA) has traditionally been considered a site-independent tool, but nowadays, there is a trend towards making LCA more site-dependent. Site-dependent characterization factors have been calculated for regional impact categories such as acidification, terrestrial and aquatic eutrophication, and smog. Specifically, for aquatic eutrophication, characterization factors have been proposed for large geographical areas (mainly European and North American countries). Those factors are not detailed enough for countries which present large geographical, climatic, and economical variability such as Spain. Therefore, this work aims to calculate the characterization factors and the normalization reference for aquatic eutrophication at a regional level, using Galicia (NW Spain), a region with increasing problems of eutrophication, as a case study. Finally, the comparison of the factors obtained here with literature values will be used to analyze the influence of spatial differentiation with increasing coverage of the causality chain.     

Spatially differentiated midpoint indicator for marine eutrophication of waterborne emissions in Sweden

Purpose

In life cycle assessment (LCA), eutrophication is commonly assessed using site-generic characterisation factors, despite being a site-dependent environmental impact. The purpose of this study was to improve the environmental relevance of marine eutrophication impact assessment in LCA, particularly regarding the impact assessment of waterborne nutrient emissions from Swedish agriculture.

Methods

Characterisation factors were derived using site-dependent data on nutrient transport for all agricultural soils in Sweden, divided into 968 catchment areas, and considering the Baltic Sea, the receiving marine compartment, as both nitrogen- and phosphorus-limited. These new characterisation factors were then applied to waterborne nutrient emissions from typical grass ley and spring barley cultivation in all catchments.

Results and discussion

The site-dependent marine eutrophication characterisation factors obtained for nutrient leaching from soils varied between 0.056 and 0.986 kg N_eq/kg N and between 0 and 7.23 kg N_eq/kg P among sites in Sweden. On applying the new characterisation factors to spring barley and grass ley cultivation at different sites in Sweden, the total marine eutrophication impact from waterborne nutrient emissions for these crops varied by up to two orders of magnitude between sites. This variation shows that site plays an important role in determining the actual impact of an emission, which means that site-dependent impact assessment could provide valuable information to life cycle assessments and increase the relevance of LCA as a tool for assessment of product-related eutrophication impacts.

Conclusions

Characterisation factors for marine eutrophication impact assessment at high spatial resolution, considering both the site-dependent fate of eutrophying compounds and specific nutrient limitations in the recipient waterbody, were developed for waterborne nutrient emissions from agriculture in Sweden. Application of the characterisation factors revealed variations in calculated impacts between sites in Sweden, highlighting the importance of spatial differentiation of characterisation modelling within the scale of the impact.

     

Improving odour assessment in LCA—the odour footprint

Purpose

Odour is an important aspect of systems for human and agricultural waste management and many technologies are developed with the sole purpose of reducing odour. Compared with greenhouse gas assessment and the assessment of toxicity, odour assessment has received little attention in the life cycle assessment (LCA) community. This article aims to redress this.

Methods

Firstly, a framework for the assessment of odour impacts in LCA was developed considering the classical LCA framework of emissions, midpoint and endpoint indicators. This suggested that an odour footprint midpoint indicator was worth striving for. An approach to calculating an areal indicator we call “odour footprint”, which considers the odour detection threshold, the diffusion rate and the kinetics of degradation of odourants, was implemented in MATLAB. We demonstrated the use of the characterisation factors we calculated in a case study based on odour removal technology applied to a pig barn.

Results and discussion

We produced a list of 33 linear characterisation factors based on hydrogen sulphide equivalents, analogous to the linear carbon dioxide equivalency factors in use in carbon footprinting, or the dichlorobenzene equivalency factors developed for assessment of toxic impacts in LCA. Like the latter, this odour footprint method does not take local populations and exposure pathway analysis into account—its intent is not to assess regulatory compliance or detailed design. The case study showed that despite the need for materials and energy, large factor reductions in odour footprint and eutrophication potential were achieved at the cost of a smaller factor increase in greenhouse emissions.

Conclusions

The odour footprint method is proposed as an improvement on the established midpoint method for odour assessment in LCA. Unlike it, the method presented here considers the persistence of odourants. Over time, we hope to increase the number of characterised odourants, enabling analysts to perform simple site-generic LCA on systems with odourant emissions.     

Global characterisation factors to assess land use impacts on biotic production

Purpose

The inclusion of land-use activities in life cycle assessment (LCA) has been subject to much debate in the LCA community. Despite the recent methodological developments in this area, the impacts of land occupation and transformation on its long-term ability to produce biomass (referred to here as biotic production potential [BPP]) — an important endpoint for the Area of Protection (AoP) Natural Resources — have been largely excluded from LCAs partly due to the lack of life cycle impact assessment methods.

Materials and methods

Several possible methods/indicators for BPP associated with biomass, carbon balance, soil erosion, salinisation, energy, soil biota and soil organic matter (SOM) were evaluated. The latter indicator was considered the most appropriate for LCA, and characterisation factors for eight land use types at the climate region level were developed.

Results and discussion

Most of the indicators assessed address land-use impacts satisfactorily for land uses that include biotic production of some kind (agriculture or silviculture). However, some fail to address potentially important land use impacts from other life cycle stages, such as those arising from transport. It is shown that the change in soil organic carbon (SOC) can be used as an indicator for impacts on BPP, because SOC relates to a range of soil properties responsible for soil resilience and fertility.

Conclusions

The characterisation factors developed suggest that the proposed approach to characterize land use impacts on BBP, despite its limitations, is both possible and robust. The availability of land-use-specific and biogeographically differentiated data on SOC makes BPP impact assessments operational. The characterisation factors provided allow for the assessment of land-use impacts on BPP, regardless of where they occur thus enabling more complete LCAs of products and services. Existing databases on every country’s terrestrial carbon stocks and land use enable the operability of this method. Furthermore, BPP impacts will be better assessed by this approach as increasingly spatially specific data are available for all geographical regions of the world at a large scale. The characterisation factors developed are applied to the case studies (Part D of this special issue), which show the practical issues related to their implementation.     

Life cycle impacts of topsoil erosion on aquatic biota: case study on <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> forest

Purpose

This study illustrates the applicability of a framework to conduct a spatially distributed inventory of suspended solids (SS) delivery to freshwater streams combined with a method to derive site-specific characterisation factors for endpoint damage on aquatic ecosystem diversity. A case study on Eucalyptus globulus stands located in Portugal was selected as an example of a land-based system. The main goal was to assess the relevance of SS delivery to freshwater streams, providing a more comprehensive assessment of the SS impact from land use systems on aquatic environments.

Methods

The WaTEM/SEDEM model, which was used to perform the SS inventory, is a raster-based empirical erosion and deposition model. This model allowed to predict the amount of SS from E. globulus stands under study and route this amount through the landscape towards the drainage network. Combining the spatially explicit SS inventory with the derived site-specific endpoint characterisation factors of SS delivered to two different river sections, the potential damages of SS on macroinvertebrates, algae and macrophytes were assessed. In addition, this damage was compared with the damage obtained with the commonly used ecosystem impact categories of the ReCiPe method.

Results and discussion

The relevance of the impact from SS delivery to freshwater streams is shown, providing a more comprehensive assessment of the SS impact from land use systems on aquatic environments. The SS impacts ranged from 15.5 to 1234.9 PDF m³.yr.ha^?1.revolution^?1 for macroinvertebrates, and from 5.2 to 411.9 PDF.m³.yr.ha^?1.revolution^?1 for algae and macrophytes.For some stands, SS potential impacts on macroinvertebrates have the same order of magnitude than freshwater eutrophication, freshwater ecotoxicity, terrestrial ecotoxicity and terrestrial acidification impacts. For algae and macrophytes, most of the stands present SS impacts of the same order of magnitude as terrestrial ecotoxicity, one order of magnitude higher than freshwater eutrophication and two orders of magnitude lower than freshwater ecotoxicity and terrestrial acidification.

Conclusions

The SS impact results allow concluding that the increase of SS in the water column can cause biodiversity damage and that the calculated impacts can have a similar or even higher contribution to the total environmental impact than the commonly used ecosystem impact categories of the ReCiPe method. A wide application of the framework and method developed at a local scale will enable the establishment of a regionalised SS inventory database and a deep characterisation of the potential environmental impacts of SS on local aquatic environments.

     

Evaluation of selection methods for toxicological impacts in LCA recommendations for OMNIITOX

Goal, Scope and Background  

The aim of this study has been to come up with recommendations on how to develop a selection method (SM) within the method development research of the OMNHTOX project. An SM is a method for prioritization of chemical emissions to be included in a Life Cycle Impact Assessment (LCIA) characterisation, in particular for (eco)toxicological impacts. It is therefore designed for pre-screening to support a characterisation method. The main reason why SMs are needed in the context of LCIA is the high number of chemical emissions that potentially contribute to the impacts on ecosystems and human health. It will often not be feasible to cover all emissions with characterisation factors and, therefore, there exists a need to focus the effort on the most significant chemical emissions in the characterisation step. Until now not all LCA studies include tox-icity-related impact categories, and when they do there are typically many gaps. This study covers the only existing methods explicitly designed as SMs (EDIP-selection, Priofactor and CPM-selection), the dominating Chemical Ranking and Scoring (CRS) method in Europe (EURAM) and in the USA (WMPT) that can be adapted for this purpose, as well as methods presenting novel approaches which could be valuable in the development of improved SMs (CART analysis and Hasse diagram technique).     

A method for improving Centre for Environmental Studies (CML) characterisation factors for metal (eco)toxicity — the case of zinc gutters and downpipes

Background, aim and scope  

The environmental impact of building products made from heavy metals has been a topic of discussion for some years. This was fuelled by results of life cycle assessments (LCAs), where the emission of heavy metals strongly effected the results. An issue was that the characterisation factors of the Centre for Environmental Studies (CML) 2000 life cycle impact assessment (LCIA) methodology put too much emphasis on the impact of metal emissions. We adjusted Zn characterisation factors according to the most recent insights in the ecotoxicity of zinc and applied them in an LCA using zinc gutters and downpipes as an example.     

Assessment of land use impacts on soil ecological functions: development of spatially differentiated characterization factors within a Canadian context

Purpose  

Among other regional impact categories in LCA, land use still lacks a suitable assessment method regarding the least developed “soil ecological quality” impact pathway. The goals of this study are to scope the framework addressing soil ecological functions and to improve the development of regionalized characterization factors (CFs). A spatially explicit approach was developed and illustrated for the Canadian context using three different regional scales and for which the extent of spatial variability was assessed.     

The anthropogenic stock extended abiotic depletion potential (AADP) as a new parameterisation to model the depletion of abiotic resources

Purpose  

Raw material availability is a cause of concern for many industrial sectors. When addressing resource consumption in life cycle assessment (LCA), current characterisation models for depletion of abiotic resources provide characterisation factors based on (surplus) energy, exergy, or extraction–reserve ratios. However, all indicators presently available share a shortcoming as they neglect the fact that large amounts of raw materials can be stored in material cycles within the technosphere. These “anthropogenic stocks” represent a significant source and can change the material availability significantly. With new characterisation factors, resource consumption in LCA will be assessed by taking into account anthropogenic material stocks in addition to the lithospheric stocks. With these characterisation factors, the scarcity of resources should be reflected more realistically.     

Quantifying system uncertainty of life cycle assessment based on Monte Carlo simulation

Background, aim, and scope

Many studies evaluate the results of applying different life cycle impact assessment (LCIA) methods to the same life cycle inventory (LCI) data and demonstrate that the assessment results would be different with different LICA methods used. Although the importance of uncertainty is recognized, most studies focus on individual stages of LCA, such as LCI and normalization and weighting stages of LCIA. However, an important question has not been answered in previous studies: Which part of the LCA processes will lead to the primary uncertainty? The understanding of the uncertainty contributions of each of the LCA components will facilitate the improvement of the credibility of LCA.

Methodology

A methodology is proposed to systematically analyze the uncertainties involved in the entire procedure of LCA. The Monte Carlo simulation is used to analyze the uncertainties associated with LCI, LCIA, and the normalization and weighting processes. Five LCIA methods are considered in this study, i.e., Eco-indicator 99, EDIP, EPS, IMPACT 2002+, and LIME. The uncertainty of the environmental performance for individual impact categories (e.g., global warming, ecotoxicity, acidification, eutrophication, photochemical smog, human health) is also calculated and compared. The LCA of municipal solid waste management strategies in Taiwan is used as a case study to illustrate the proposed methodology.

Results

The primary uncertainty source in the case study is the LCI stage under a given LCIA method. In comparison with various LCIA methods, EDIP has the highest uncertainty and Eco-indicator 99 the lowest uncertainty. Setting aside the uncertainty caused by LCI, the weighting step has higher uncertainty than the normalization step when Eco-indicator 99 is used. Comparing the uncertainty of various impact categories, the lowest is global warming, followed by eutrophication. Ecotoxicity, human health, and photochemical smog have higher uncertainty.

Discussion

In this case study of municipal waste management, it is confirmed that different LCIA methods would generate different assessment results. In other words, selection of LCIA methods is an important source of uncertainty. In this study, the impacts of human health, ecotoxicity, and photochemical smog can vary a lot when the uncertainties of LCI and LCIA procedures are considered. For the purpose of reducing the errors of impact estimation because of geographic differences, it is important to determine whether and which modifications of assessment of impact categories based on local conditions are necessary.

Conclusions

This study develops a methodology of systematically evaluating the uncertainties involved in the entire LCA procedure to identify the contributions of different assessment stages to the overall uncertainty. Which modifications of the assessment of impact categories are needed can be determined based on the comparison of uncertainty of impact categories.

Recommendations and perspectives

Such an assessment of the system uncertainty of LCA will facilitate the improvement of LCA. If the main source of uncertainty is the LCI stage, the researchers should focus on the data quality of the LCI data. If the primary source of uncertainty is the LCIA stage, direct application of LCIA to non-LCIA software developing nations should be avoided.     

The role of atmospheric dispersion models and ecosystem sensitivity in the determination of characterisation factors for acidifying and eutrophying emissions in LCIA

Background, aim and scope  The methodological choices and framework to assess environmental impacts in life cycle assessment are still under discussion. Despite intensive developments worldwide, few attempts have been made hitherto to systematically present the role of different factors of characterisation models in life cycle impact assessment (LCIA). The aim of this study is to show how European average and country-dependent characterisation factors for acidifying and eutrophying emissions differ when using (a) acidifying and eutrophying potentials alone, (b) depositions from an atmospheric dispersion model or (c) critical loads in conjunction with those depositions. Furthermore, in the latter case, the contributions of emissions, an atmospheric transport model and critical loads to changes in characterisation factors of NO₂ are studied. In addition, the new characterisation factors based on the accumulated exceedance (AE) method are presented using updated emissions, a new atmospheric transport model and the latest critical loads. Materials and methods  In this study, characterisation factors for acidifying and eutrophying emissions are calculated by three different methods. In the ‘no fate’ (NF) methods, acidifying and eutrophying potentials alone are considered as characterisation factors. In the ‘only above terrestrial environment’ (OT) approach, characterisation factors are based on the deposition of the acidifying or eutrophying substances to terrestrial land surfaces. The third method is the so-called AE method in which critical loads are used in conjunction with depositions. The results of the methods are compared both at the European and the country level using weighted mean, weighted standard deviation, minimum and maximum values. To illustrate the sensitivity of the AE method, changes in European emissions, employed atmospheric dispersion model and the critical loads database are conducted step-by-step, and the differences between the results are analysed. Results and discussion  For European average characterisation factors, the three characterisation methods of acidification produce results in which the contributions of NH₃, NO₂ and SO₂ to the acidification indicator do not differ much within each method when 1 kg of each acidifying substance is emitted. However, the NF methods cannot describe any spatial aspects of environmental problems. Both OT and AE methods show that the spatial aspects play an important role in the characterisation factors. The AE method results in greater differentiations between country-dependent characterisation factors than does the OT method. In addition, the results of the AE and OT methods differ from each other for individual countries. A major shortcoming of the OT approach is that it does not consider the sensitivity of the ecosystems onto which the pollutants are deposited, whereas the AE approach does. In the case of the AE method, a new atmospheric dispersion model, new information on emissions and critical loads have a different influence on the characterisation factors, depending on the country. The results of statistics show that the change in the atmospheric dispersion model has a greatest influence on the results, since ecosystem-specific depositions are taken into account for the first time. Conclusions and recommendations  The simple NF methods can be used in a first approximation to assess the impacts of acidification and terrestrial eutrophication in cases where we do not know where the emissions occur. The OT approach is a more advanced method compared with the NF method, but its capability to describe spatial aspects is limited. The AE factors are truly impact-oriented characterisation factors and the information used here represents the current best knowledge about the assessment practice of acidification and terrestrial eutrophication in Europe. The key message of this study is that there is no shortcut to achieving advanced characterisation of acidification and terrestrial eutrophication: an advanced methodology cannot develop without atmospheric dispersion models and information on ecosystem sensitivity.     

An environmental comparison of biocomposite film based on orange peel-derived pectin jelly-corn starch and LDPE film: LCA and biodegradability

Purpose

A new biodegradable film, based on orange peel-derived pectin jelly and corn starch developed in our labs, was environmentally compared with a low-density polyethylene (LDPE) film. An environmental assessment was realized in two stages to individually determine the environmental impact resulting from production-shaping processes and the biodegradation performance of the films.

Methods

Firstly, a prospective cradle-to-gate life cycle assessment (LCA) was performed using a CML-IA method implemented in SimaPro 8.0.1. Secondly, an aerobic biodegradation was simulated as directly disposing of the films in soil according to ASTM D 5988–03. The functional unit considered in this study was 1 m² of packaging film. The films were compared for impact categories of abiotic depletion (elements and fossil fuel), global warming potential, ozone layer depletion, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial ecotoxicity, photochemical oxidation, acidification, and eutrophication. A Monte Carlo simulation was realized to determine the uncertainty levels. According to impact assessment results and major sources of uncertainties, two predictive improvement scenarios were performed for commercial scale production and compared with biocomposite film at the laboratory scale.

Results and discussion

LCA results show that biocomposite film has a slightly higher impact than LDPE film for all categories with probabilities ranging between 50 and 100 % except for acidification. The categories that have uncertainty (terrestrial ecotoxicity, abiotic depletion (element), photochemical oxidation, human toxicity, and fresh water aquatic ecotoxicity) were mainly resulted from electricity consumption for extrusion and film forming and modified starch addition. These two processes are mainly responsible for the environmental impact of the biocomposite film.

Conclusions

Prospective LCA showed that improvement of the process in this manner would decrease the environmental impact. On the other hand, the maximum level of biodegradation achieved in the biocomposite film is 78.4 %, whereas that for the LDPE film is 40.4 % with CO₂ production rates of 1.97 and 1.17 mmol CO₂/day, respectively.

     

Uncertainty in LCA case study due to allocation approaches and life cycle impact assessment methods

Purpose

Uncertainty is present in many forms in life cycle assessment (LCA). However, little attention has been paid to analyze the variability that methodological choices have on LCA outcomes. To address this variability, common practice is to conduct a sensitivity analysis, which is sometimes treated only at a qualitative level. Hence, the purpose of this paper was to evaluate the uncertainty and the sensitivity in the LCA of swine production due to two methodological choices: the allocation approach and the life cycle impact assessment (LCIA) method.

Methods

We used a comparative case study of swine production to address uncertainty due to methodological choices. First, scenario variation through a sensitivity analysis of the approaches used to address the multi-functionality problem was conducted for the main processes of the system product, followed by an impact assessment using five LCIA methods at the midpoint level. The results from the sensitivity analysis were used to generate 10,000 independent simulations using the Monte Carlo method and then compared using comparison indicators in histogram graphics.

Results and discussion

Regardless of the differences between the absolute values of the LCA obtained due to the allocation approach and LCIA methods used, the overall ranking of scenarios did not change. The use of the substitution method to address the multi-functional processes in swine production showed the highest values for almost all of the impact categories, except for freshwater ecotoxicity; therefore, this method introduced the greater variations into our analysis. Regarding the variation of the LCIA method, for acidification, eutrophication, and freshwater ecotoxicity, the results were very sensitive. The uncertainty analysis with the Monte Carlo simulations showed a wide range of results and an almost equal probability of all the scenarios be the preferable option to decrease the impacts on acidification, eutrophication, and freshwater ecotoxicity. Considering the aggregate result variation across allocation approaches and LCIA methods, the uncertainty is too high to identify a statistically significant alternative.

Conclusions

The uncertainty analysis showed that performing only a sensitivity analysis could mislead the decision-maker with respect to LCA results; our analysis with the Monte Carlo simulation indicates no significant difference between the alternatives compared. Although the uncertainty in the LCA outcomes could not be decreased due to the wide range of possible results, to some extent, the uncertainty analysis can lead to a less uncertain decision-making by demonstrating the uncertainties between the compared alternatives.

     

Life cycle assessment in green chemistry: overview of key parameters and methodological concerns

Purpose

Several articles within the area of green chemistry often promote new techniques or products as ‘green’ or ‘more environmentally benign’ than their conventional counterpart although these articles often do not quantitatively assess the environmental performance. In order to do this, life cycle assessment (LCA) is a valuable methodology. However, on the planning stage, a full-scale LCA is considered to be too time consuming and complicated. Two reasons for this have been recognised, the method is too comprehensive and it is hard to find inventory data. In this review, key parameters are presented with the purpose to reduce the time-consuming steps in LCA.

Methods

In this review, several LCAs of so-called ‘green chemicals’ are analysed and key parameters and methodological concerns are identified. Further, some conclusions on the environmental performance of chemicals were drawn.

Results and discussion

For fossil-based platform chemicals several LCAs exists but for chemicals produced with industrial biotechnology or from renewable resources the number of LCAs is limited, with the exception of biofuels, for which a large number of studies are made. In the review, a significant difference in the environmental performance of bulk and fine chemicals was identified. The environmental performance of bulk chemicals are closely connected to the production of the raw material and thereby different land use aspects. Here, a lot can be learnt from biofuel LCAs. In many of the reviewed articles focusing on bulk chemicals a comparison regarding fossil and renewable raw material was done. In most of the comparisons the renewable alternative turned out to be more environmentally preferable, especially for the impact on GWP and energy use. However, some environmental concerns were identified as important to include to assess overall environmental concern, for example eutrophication and the use of land.

Conclusions

To assess the environmental performance of green chemicals, quantitative methods are needed. For this purpose, both simple metrics and more comprehensive methods have been developed, one recognised method being LCA. However, this method is often too time consuming to be valuable in the process planning stage. This is partly due to a lack of available inventory data, but also because the method itself is too comprehensive. Here, key parameters for the environmental performance and methodological concerns were described to facilitate a faster and simpler use of LCA of green chemicals in the future.     

Life cycle assessment of a biobased chainsaw oil made on the farm in Wallonia

Purpose

The environmental issue is a particular concern for chainsaw oils because these fluids represent a total loss system. The aim of this study is to quantify the environmental impacts of a biobased chainsaw oil made on the farm in Wallonia (a region of Belgium) and to compare it with a model mineral chainsaw oil. With this study, the aim is also to participate in the development of the life cycle assessment (LCA) methodology applied to the biolubricant sector since LCAs on these products are quite limited and rarely sufficiently detailed.

Method

In this LCA, the attributional approach is applied. Seven impact categories are studied. The methods for life cycle impact assessment are IPCC, ReCiPe, CML and USEtox. The functional unit is 1 kg of base oil. Seven sensitivity analyses are performed.

Results and discussion

Results indicate that the biobased chainsaw oil made on the farm has a lower impact for the global warming potential, the abiotic depletion potential, the ozone depletion potential and the photochemical oxidation potential. On the contrary, it has larger acidification, aquatic eutrophication and aquatic ecotoxicity potential impacts. Regarding the contribution of the life cycle stages of the biobased chainsaw oil, the agricultural stage causes the highest contribution in all impact categories. For the mineral chainsaw oil, the refining stage is preponderant for all impact categories except for the global warming potential for which the end-of-life stage contributes the most. When taking additives into account, conclusions regarding the comparison between the oils are not reversed. Even if it was necessary to consume more biobased than mineral chainsaw oil, conclusions regarding the comparison of the oils would not be reversed. In the same way, a different allocation procedure for rapeseed oil and rape meal, a different rape seeds yield or different extraction yields in the refining stage of the mineral base oil do not change the results of the comparison. For the biobased chainsaw oil, the substitution of only one active substance in the agricultural stage could result in an important decrease of the freshwater ecotoxicity impact.

Conclusions

The biobased chainsaw oil has a lower impact in four out of the seven impact categories and a higher impact in three impact categories. By providing a detailed LCA on a biobased chainsaw oil, this study contributes to the development of LCA applied to biobased lubricants.     

Uncertainties in the application of the species area relationship for characterisation factors of land occupation in life cycle assessment

Purpose  

Uncertainties in land use damage modeling are recognized, but hardly quantified in life cycle assessment (LCA). The objective of this study is to analyze the influence of various key assumptions and uncertainties within the development of characterisation factors (CFs) for land use in LCA. We assessed the influence on land use CFs of (1) parameter uncertainty and (2) the choice for a constant or land use-specific species accumulation factor z and including or excluding regional effects.     

Life cycle assessment of a waste lubricant oil management system

Purpose

This paper compares 16 waste lubricant oil (WLO) systems (15 management alternatives and a system in use in Portugal) using a life cycle assessment (LCA). The alternatives tested use various mild processing techniques and recovery options: recycling during expanded clay production, recycling and electric energy production, re-refining, energy recovery during cement production, and energy recovery during expanded clay production.

Methods

The proposed 15 alternatives and the actual present day situation were analyzed using LCA software UMBERTO 5.5, applied to eight environmental impact categories. The LCA included an expansion system to accommodate co-products.

Results

The results show that mild processing with low liquid gas fuel consumption and re-refining is the best option to manage WLO with regard to abiotic depletion, eutrophication, global warming, and human toxicity environmental impacts. A further environmental option is to treat the WLO using the same mild processing technique, but then send it to expanded clay recycling to be used as a fuel in expanded clay production, as this is the best option regarding freshwater sedimental ecotoxicity, freshwater aquatic ecotoxicity, and acidification.

Conclusions

It is recommended that there is a shift away from recycling and electric energy production. Although sensitivity analysis shows re-refining and energy recovery in expanded clay production are sensitive to unit location and substituted products emission factors, the LCA analysis as a whole shows that both options are good recovery options; re-refining is the preferable option because it is closer to the New Waste Framework Directive waste hierarchy principle.     

Categorizing water for LCA inventory

Purpose  

As impact assessment methods for water use in LCA evolve, so must inventory methods. Water categories that consider water quality must be defined within life cycle inventory. The method presented here aims to establish water categories by source, quality parameter and user.     

Analysis of the different techniques to include noise damage in life cycle assessment. A case study for car tires

Purpose

Despite that different methods for the inclusion of transport noise in life cycle assessment (LCA) have been proposed, none of them has become consensual. Leveraging a case study on car tires, this paper aims at comparing two among these characterization approaches to identify strengths and weaknesses and to investigate the relative contribution of noise to human health (in disability-adjusted life years (DALYs)) as compared to other environmental stressors.

Methods

The case study analyzed two tires showing different acoustical properties. The two methods applied are the one developed by Müller-Wenk and further improved by other authors and the recent one proposed by Cucurachi. These two methods were adapted to the case study, and a full LCA study of the car tires was carried out. Both uncertainty and sensitivity analyses were performed.

Results and discussion

Both methods highlight the potential high contribution of noise damage to the DALYs generated by car tires, even considering parameters’ uncertainties. This study shows therefore the necessity to integrate noise impact in LCA in a broader way. Both methods present coherent results regarding the environmental performance differences between the two products. However, the absolute DALY scores differ by eight orders of magnitude, probably because Cucurachi’s methods overestimate the damages. The analysis of modeling choices and parameter uncertainties could not explain this difference.

Conclusions

Noise impact on human health has to be included in LCA, and additional efforts should focus on the characterization modeling since there is not yet a consensual method for a systematic integration. The case study shows that the improvement of tire design can efficiently reduce noise impact on human health. Both methods have advantages and inconveniences. We think that it is possible to elaborate a method combining the strengths of both approaches. An incremental approach used on accurate localized and temporalized data processed with noise propagation software could provide characterization factors for a set of archetypes. This should be a good compromise for a method allowing systematic integration of noise impact in LCA.

     

Weighting in LCA Based on Ecotaxes - Development of a Mid-point Method and Experiences from Case Studies

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DOI: http://dx.doi.org/10.1065/lca2006.04.015

Goal, Scope and Background

The weighting phase in Life Cycle Assessment (LCA) is and has always been a controversial issue, partly because this element requires the incorporation of social, political and ethical values. Despite the controversies, weighting is widely used in practise. In this paper we will present an approach for monetisation of environmental impacts which is based on the consistent use of ecotaxes and fees in Sweden as a basis for the economic values. The idea behind this approach is that taxes and fees are expressions of the values society places on resource uses and emissions. An underlying assumption for this is that the decisions taken by policy-makers are reflecting societal values thus reflecting a positive view of representative democracy.

Methods

In the method a number of different ecotaxes are used. In many cases they can directly be used as valuation weighting factors, an example is the CO2-tax that can be used as a valuation of CO2-emissions. In some cases, a calculation has to be made in order to derive a weighting factor. An example of this is the tax on nitrogen fertilisers which can be recalculated to an emission of nitrogen which can be used as a weighting factor for nitrogen emissions. The valuation weighting factors can be connected to characterisation methods in the normal LCA practise. We have often used the Ecotax method in parallel to other weighting methods such as the Ecoindicator and EPS methods and the results are compared.

Results and Discussion

A new set of weighting factors has been developed which has been used in case studies. It is interesting to note that the Ecotax method is able to identify different environmental problems as the most important ones in different case studies. In some cases, the Ecotax method has identified some interventions as the most important ones which lack weighting factors in other weighting methods. The midpoint-endpoint debate in the LCA literature has often centred on different types of uncertainties. Sometimes it is claimed that an advantage with having an endpoint approach is that the weighting would be easier and less uncertain. Here we are however suggesting a mid-point weighting method that we claim are no less uncertain than other often used weighting methods based on a damage assessment. This paper can therefore be seen as a discussion paper also in the midpoint-endpoint debate.

Conclusion and Recommendation

The Ecotax method is ready to use. It should be further updated and developed as taxes are changed and new characterisation methods are developed. The method is not only relevant for LCA but also for other environmental systems analysis. The Ecotax method has also been used as a valuation method for Cost-Benefit Analysis (CBA), Life Cycle Costing (LCC) and within the context of a Strategic Environmental Assessment (SEA).