The environmental impact of nitrous oxide inhalation sedation appointments and equipment used in dentistry

PURPOSE

This paper reports a life cycle impact assessment (LCIA) to calculate the environmental footprint of a dental appointment using N2O, comparing single-use equipment with reusable equipment. Nitrous oxide (N2O) is used successfully in dentistry to provide sedation and pain relief to anxious patients, most commonly in children. However, N2O is a powerful climate pollutant 298 times more damaging than carbon dioxide over a 100-year estimate.

METHODS

The functional unit chosen for this LCIA was 30 min delivery of N2O to oxygen in a 50:50 ratio at 6 L per minute flow rate as inhalation sedation to one patient. Two types of equipment were compared to deliver the anaesthetic gas: reusable and disposable items.

RESULTS

The use of disposable equipment for N2O sedation produces a significantly larger environmental impact across nearly all of the environmental impact scores, but the overall global warming potential is comparable for both types of equipment due to the vast environmental pollution from N2O itself.

CONCLUSION

N2O sedation is a reliable treatment adjunct but contributes to climate change. Single-use equipment has a further deleterious effect on the environment, though this is small compared to the overall impact of N2O. Dental priorities should be to deliver safe and effective care to patients that protects staff, minimises waste and mitigates impact on the environment alongside promoting research into alternatives.

Potential environmental and human health menace of spent graphite in lithium-ion batteries

The growing demand for lithium-ion batteries for portable electronics and electric vehicles results in a booming lithium battery market, leading to a concomitant increase in spent graphite. This research investigated the potential impacts of spent graphite on environmental and human health using standardized toxicity extraction and Life Cycle Impact Assessment models. The spent graphite samples were classified as hazardous waste due to the average nickel content of 337.14 mg/L according to Chinese regulations. Besides, cadmium and fluorine were the other elements that exceeded the regulations threshold. Easily ignored aluminum and heavy metal cobalt are other harmful elements according to the results of Life Cycle Impact Assessments. All the metallic harmful elements mainly exist in a transferable state. Thermogravimetry infrared spectrometry coupled with mass spectrometry was employed to recognize the emitted gases and explore gas emission behavior. Inorganic gases of CO, H2S, SO2, SO3, oxynitride, HCl, and fluoride-containing gases were detected. Sulfur-containing gases released from spent graphite were contributed by the residual sulfuric acid after leaching. The correlation between the evolution of emitted gases and the heating schedule was established simultaneously. The research comprehensively illustrates the pollution of spent graphite and provides assistance for the design of green recycling schemes for spent graphite.

Global regionalized characterization factors for phosphorus and nitrogen impacts on freshwater fish biodiversity

Inefficient global nutrient (i.e., phosphorus (P) and nitrogen (N)) management leads to an increase in nutrient delivery to freshwater and coastal ecosystems and induces eutrophication in these aquatic environments. This process threatens the various species inhabiting these ecosystems. In this study, we developed regionalized characterization factors (CFs) for freshwater eutrophication at 0.5 × 0.5-degree resolution, considering different fates for direct emissions to freshwater, diffuse emissions, and increased erosion due to agricultural land use. The CFs were provided for global and regional species loss of freshwater fish. CFs for global species loss were quantified by integrating global extinction probabilities. Results showed that the CFs for P and N impacts on freshwater fish are higher in densely populated regions that encompass either large lakes or the headwaters of large rivers. Focusing on nutrient-limited areas increases country-level CFs in 51.9 % of the countries for P and 49.5 % of the countries for N compared to not considering nutrient limitation. This study highlights the relevance of considering freshwater eutrophication impacts via both P and N emissions and identifying the limiting nutrient when performing life cycle impact assessments.

Comparative life cycle assessment of a novel sustainable road pavement system adopting recycled plastic from PET bottles and carbonated aggregate

Road surfacing is crucial in improving community accessibility and mobility. Adopting sustainable measures is extremely important to prevent the significantly high environmental burdens associated with road pavement systems production. This study presents a comparative life cycle assessment of traditional pavement systems and their sustainable alternatives made and tested at the London South Bank University laboratories. The low-impact pavement mixes proposed herein provide a novel, innovative method for producing sustainable road systems. Unlike traditional approaches, these asphalt mixes utilise materials derived from recycled polyethylene terephthalate (plastics) and carbonated aggregates and are produced at temperatures significantly lower (warm mix). The Simapro software (Consultants, 2023) [1] was used to model the analysed asphalt mixes, and all life cycle inputs and outputs were characterised during the life cycle impact assessment phase into potential impacts using the IMPACT World + Midpoint method. Additionally, an uncertainty analysis employing Monte Carlo simulation was conducted to validate the life cycle assessment findings, reinforcing the robustness and credibility of this study's results. Notably, the assessment shows substantial reductions in the environmental impact of road pavement mixes adopting recycled plastic and carbonated aggregates, with various outcomes. Compared to traditional mixes, Climate Change emissions are reduced by approximately 40 %-60 %, Marine Eutrophication exhibits reductions of up to 30 %, and Freshwater Eutrophication decreases by up to 20 %. These findings suggest that integrating this sustainable road pavement approach can significantly reduce the environmental burdens of asphalt production and give asphalt a pivotal role in tackling waste reduction, carbon sequestration, and achieving Net Zero. Also, the proposed system can positively contribute to the current United Kingdom's (UK) circular policy model by reconsidering current waste management frameworks and integrating more efficient settings.

Micro- and nanoplastics in soil: Linking sources to damage on soil ecosystem services in life cycle assessment

Soil ecosystems are crucial for providing vital ecosystem services (ES), and are increasingly pressured by the intensification and expansion of human activities, leading to potentially harmful consequences for their related ES provision. Micro- and nanoplastics (MNPs), associated with releases from various human activities, have become prevalent in various soil ecosystems and pose a global threat. Life Cycle Assessment (LCA), a tool for evaluating environmental performance of product and technology life cycles, has yet to adequately include MNPs-related damage to soil ES, owing to factors like uncertainties in MNPs environmental fate and ecotoxicological effects, and characterizing related damage on soil species loss, functional diversity, and ES. This study aims to address this gap by providing as a first step an overview of the current understanding of MNPs in soil ecosystems and proposing a conceptual approach to link MNPs impacts to soil ES damage. We find that MNPs pervade soil ecosystems worldwide, introduced through various pathways, including wastewater discharge, urban runoff, atmospheric deposition, and degradation of larger plastic debris. MNPs can inflict a range of ecotoxicity effects on soil species, including physical harm, chemical toxicity, and pollutants bioaccumulation. Methods to translate these impacts into damage on ES are under development and typically focus on discrete, yet not fully integrated aspects along the impact-to-damage pathway. We propose a conceptual framework for linking different MNPs effects on soil organisms to damage on soil species loss, functional diversity loss and loss of ES, and elaborate on each link. Proposed underlying approaches include the Threshold Indicator Taxa Analysis (TITAN) for translating ecotoxicological effects associated with MNPs into quantitative measures of soil species diversity damage; trait-based approaches for linking soil species loss to functional diversity loss; and ecological networks and Bayesian Belief Networks for linking functional diversity loss to soil ES damage. With the proposed conceptual framework, our study constitutes a starting point for including the characterization of MNPs-related damage on soil ES in LCA.

Preciseness, rather than simplicity, is required to assess pesticide reduction strategies: Findings from rice production in Japan

Pesticide reduction is given high priority in the worldwide sustainability agenda. The reduction of pesticide impacts, rather than the reduction of application rates, has become a common criterion for monitoring policy progress. However, simplicity-an essential requirement in improving the applicability of pesticide impact assessment-may distort the accuracy of the evaluation and therefore prevent effective pesticide reduction. Here, we present contrasting results that underscore how the selection of evaluation methods that differ in simplicity affects the assessment results of pesticide reduction strategies. Briefly, we analysed the impact of conversion from conventional to low-input management adopting both a simplified linear-based method and a precise method that includes newly calculated nonlinear approach-based characterization factors for 109 active ingredients (AIs). The two methods were then used to estimate the freshwater ecotoxicity impact of eight rice farms in Japan where both conventional pesticide application and pesticide reduction strategies are practiced. The results show that the simplified method generated anomalies at the farm level through overestimation and underestimation of the individual AI impacts. Patterns that contributed to extreme changes of impact at the farm level were also identified. These findings suggest a strong need for a precise evaluation method for effectively monitoring policy progress at the farm level.

How can ecosystem status be more comprehensively reflected? A case study of Jinan City, China

Ecosystems provide benefits to human well-being, but highly concentrated human activities also cause environmental pressure. Previous studies focused only on one aspect: either ecosystem services (ESs) or ecosystem damage (ED). To provide comprehensive view of ecosystem status in the selected study area, an integrated ecosystem performance analytic framework was established based on the ED-ESs synergistic effect. This study quantitatively analyzed the dynamic variation in ecosystem status from both ED and ESs perspectives with a case study of Jinan City, China, from 2000 to 2020. The results showed that the environmental and economic impacts caused by pollution were 692.87 species.year and $15.58 × 10⁸ in 2020, respectively, and they were mainly derived from energy consumption. Regarding ESs, three regulating services (water retention, soil retention, and carbon sequestration) increased from south to north, whereas material services presented the opposite trend. Ecosystem service value had declined after peaking in 2010 when material services contributed the most. Overall, the Jinan City suffered from ecosystem decline, with ecosystem performance on a downward trend from 2000 to 2020. Finally, the characterization factors of four ESs were appropriately incorporated into the life cycle impact assessment to drive the evolution in ecosystem performance calculations.

Comparative selective pressure potential of antibiotics in the environment

To guide both environmental and public health policy, it is important to assess the degree of antibiotic resistance selection pressure under measured environmental concentrations (MECs), and to compare the efficacy of different mitigation strategies to minimize the spread of resistance. To this end, the resistance selection and enrichment potential due to antibiotic emissions into the environment must be analysed from a life cycle perspective, for a wide range of antibiotics, and considering variations in the underlying fitness costs between different resistance mutations and genes. The aim of this study is to consistently derive fitness cost-dependent minimum selective concentrations (MSCs) from readily available bacterial inhibition data and to build MSC-based species sensitivity distributions (SSDs). These are then used to determine antibiotic-specific resistance selection concentrations predicted to promote resistance in 5% of exposed bacterial species (RSC₅). Using a previously developed competition model, we provide estimated MSC₁₀ endpoints for 2,984 antibiotic and bacterial species combinations; the largest set of modelled MSCs available to date. Based on constructed SSDs, we derive RSC₅ for 128 antibiotics with four orders of magnitude difference in their 'selective pressure potential' in the environment. By comparing our RSC₅ to MECs, we highlight specific environmental compartments (e.g. hospital and wastewater effluents, lakes and rivers), as well as several antibiotics (e.g. ciprofloxacin, norfloxacin, enrofloxacin, and tetracycline), to be scrutinized for their potential role in resistance selection and dissemination. In addition to enabling comparative risk screening of the selective pressure potential of multiple antibiotics, our SSD-derived RSC₅ provide the point of departure for calculating new life cycle-based characterization factors for antibiotics to compare mitigation strategies, thereby contributing towards a 'One-Health' approach to tackling the global antibiotic resistance crisis.

Linking freshwater ecotoxicity to damage on ecosystem services in life cycle assessment

Freshwater ecosystems provide major benefits to human wellbeing-so-called ecosystem services (ES)-but are currently threatened among others by ecotoxicological pressure from chemicals reaching the environment. There is an increased motivation to incorporate ES in quantification tools that support decision-making, such as life cycle assessment (LCA). However, mechanistic models and frameworks that can systematically translate ecotoxicity effect data from chemical tests into eventual damage on species diversity, functional diversity, and ES in the field are still missing. While current approaches focus on translating predicted ecotoxicity impacts to damage in terms of species loss, no approaches are available in LCA and other comparative assessment frameworks for linking ecotoxicity to damage on ecosystem functioning or ES. To overcome this challenge, we propose a way forward based on evaluating available approaches to characterize damage of chemical pollution on freshwater ES. We first outline an overall framework for linking freshwater ecotoxicity effects to damage on related ES in compliance with the boundary conditions of quantitative, comparative assessments. Second, within the proposed framework, we present possible approaches for stepwise linking ecotoxicity effects to species loss, functional diversity loss, and damage on ES. Finally, we discuss strengths, limitations, and data availability of possible approaches for each step. Although most approaches for directly deriving damage on ES from either species loss or damage to functional diversity have not been operationalized, there are some promising ways forward. The Threshold Indicator Taxa ANalysis (TITAN) seems suitable to translate predicted ecotoxicity effects to a metric of quantitative damage on species diversity. A Trait Probability Density Framework (TPD) approach that incorporates various functional diversity components and functional groups could be adapted to link species loss to functional diversity loss. An Ecological Production Function (EPF) approach seems most promising for further linking functional diversity loss to damage on ES flows for human wellbeing. However, in order to integrate the entire pathway from predicted freshwater ecotoxicity to damage on ES into LCA and other comparative frameworks, the approaches adopted for each step need to be harmonized in terms of assumptions, boundary conditions and consistent interfaces with each other.

Ecotoxicity characterization of chemicals: Global recommendations and implementation in USEtox

Chemicals emitted to the environment affect ecosystem health from local to global scale, and reducing chemical impacts has become an important element of European and global sustainability efforts. The present work advances ecotoxicity characterization of chemicals in life cycle impact assessment by proposing recommendations resulting from international expert workshops and work conducted under the umbrella of the UNEP-SETAC Life Cycle Initiative in the GLAM project (Global guidance on environmental life cycle impact assessment indicators). We include specific recommendations for broadening the assessment scope through proposing to introduce additional environmental compartments beyond freshwater and related ecotoxicity indicators, as well as for adapting the ecotoxicity effect modelling approach to better reflect environmentally relevant exposure levels and including to a larger extent chronic test data. As result, we (1) propose a consistent mathematical framework for calculating freshwater ecotoxicity characterization factors and their underlying fate, exposure and effect parameters; (2) implement the framework into the USEtox scientific consensus model; (3) calculate characterization factors for chemicals reported in an inventory of a life cycle assessment case study on rice production and consumption; and (4) investigate the influence of effect data selection criteria on resulting indicator scores. Our results highlight the need for careful interpretation of life cycle assessment impact scores in light of robustness of underlying species sensitivity distributions. Next steps are to apply the recommended characterization framework in additional case studies, and to adapt it to soil, sediment and the marine environment. Our framework is applicable for evaluating chemicals in life cycle assessment, chemical and environmental footprinting, chemical substitution, risk screening, chemical prioritization, and comparison with environmental sustainability targets.

Spatially differentiated marine eutrophication method for absolute environmental sustainability assessments

Marine eutrophication and hypoxia caused by excess nutrient availability is a growing environmental problem. In this study, we explore marine nitrogen enrichment in the context of Absolute Environmental Sustainability Assessment (AESA), a method combining life cycle assessment (LCA) with environmental boundaries aiming to compare environmental impacts from an activity (product or system) with the safe operating space (SOS) for the activity. Specifically, we aim to increase the spatial resolution and improve life cycle impact assessment (LCIA) models for marine eutrophication for use in AESAs. By estimating a proxy of the areal extent of eutrophication and hypoxia in coastal large marine ecosystems (LME), we increased model resolution from 66 LMEs in the original LCIA method to 289 coastal LME subsegments and updated relevant LME parameters to the new scale (residence time, bottom water volume, reference O₂ concentration, primary production rates and depths). The new method was tested and validated by comparing the global and spatially differentiated occupation of SOS by global nitrogen emissions with observations and it showed an improved ability to identify critical areas where the SOS is exceeded, in accordance with observations of hypoxic events. Despite limitations such as the estimation of benthic zone volume and low spatial differentiation of environmental boundaries, the method can be used by AESA and LCA practitioners wishing to assess the impact of nitrogen release on marine eutrophication with a higher and more relevant spatial resolution.

Revisiting the application and methodological extensions of the planetary boundaries for sustainability assessment

The planetary boundaries (PBs) delineating the safe operating space for human activities have been broadly recognized as a well-grounded framework for global sustainability assessment. This paper provides a comprehensive review of the application and methodological extensions of the PBs by linking with multiscale environmental sustainability assessments. We find that the targeted scales, sharing principles and sustainability perspectives jointly determine the downscaling of the PBs-a complex process that needs to take into account the biophysical, socioeconomic, ethical and cultural dimensions. Despite the varying sharing principles, in general both top-down and bottom-up approaches have been employed to define the environmental boundaries at sub-global scales on which the various PBs highly differ in their threshold behaviors. To clarify the responsibility of different stakeholders for sustainable development, the PB-informed sustainability assessment should refer to a specific perspective (i.e., production-, consumption-, or life cycle-based). Furthermore, the methodological extensions of PBs have the potential to monitor the progress and gaps of the globally consensus-based Sustainable Development Goals (SDGs). To achieve the SDGs within the PBs, there is a great need for a thorough transition of socioeconomic systems towards a prosperous, just and sustainable future.

A high-resolution life cycle impact assessment model for continental freshwater habitat change due to water consumption

Global value chains and climate change have a significant impact on water resources and increasingly threaten freshwater ecosystems. Recent methodological proposals for life cycle impact assessment (LCIA), evaluate water use impacts on freshwater habitats based on river hydraulic parameters alterations. However, they are limited to French rivers due to lack of global data and models. On this basis, this article proposes an approach to compute regionalized characterization factors for modeling river habitat change potential (HCP) induced by water consumption, potentially applicable worldwide. A simplified model is developed for fish guilds and invertebrates. Based on French datasets, it establishes a relationship between HCP and river hydraulic parameters. A methodology to derive discharge and hydraulic geometry at the reach scale is proposed and applied to European and Middle Eastern rivers below 60°N latitude. Regionalized HCPs are calculated at the river reach scale and aggregated at watershed. Then, the impact of agricultural water use in contrasted European and Middle Eastern countries is evaluated comparing the outcomes from the HCP and the Available Water Remaining (AWARE) models at the national scale, considering water supply mix data. The same analysis is carried out on selected river basins. Finally, result consistency, uncertainty and global applicability of the overall approach are discussed. The study demonstrates the reproducibility of the impact model developed for French rivers on any hydrographic network where comparable ecological, hydrological and hydraulic conditions are met. Furthermore, it highlights the need to characterize impacts at a higher spatial resolution in areas where HCP is higher. Large scale quantification of HCP opens the way to the operationalization of mechanistic LCIA models in which the habitat preferences of freshwater species are taken into account to assess the impacts of water consumption on biodiversity.

Quantifying global warming potential of alternative biorefinery systems for producing fuels from Chinese food waste

Biorefining of Chinese food waste (FW) into transport fuels was assessed in terms of amount of fuel produced and over all Global Warming Potential (GWP) for six different scenarios including biogas, biomethane, bioethanol and biodiesel in different combinations. The life-cycle perspective used included GWP aspects of material and energy use, emissions during biorefining and management of residues, as well as substitution of fossil fuels according to the energy content of biofuels. All of the six FW biorefineries revealed savings in GWP ranging from -19 to -138 kg CO₂ eqv. per ton of wet FW. Compared to the reference scenario with only anaerobic digestion (S0), introducing biogas upgrading to biomethane (S1) improved the GWP by 37%; while producing bioethanol prior to anaerobic digestion (S2) decreased the savings in GWP. Introducing biodiesel prior to anaerobic digestion (S3) revealed around 60% improvement in GWP, while combining biodiesel and biomethane gave the largest improvement in GWP, 84% compared to the reference scenario, and the most fuels (around 2400 MJ in terms of 30 kg biodiesel and 35 kg biomethane per ton of wet FW). A sensitivity analysis revealed that the electricity production based on the biogas was an important parameter and appears in all refineries, while the results was less sensitive to the production of biodiesel and biomethane. The residue management contributed also to the GWP, but did not vary much among the biorefinery scenarios.

Exposure and Toxicity Characterization of Chemical Emissions and Chemicals in Products: Global Recommendations and Implementation in USEtox

PURPOSE

Reducing chemical pressure on human and environmental health is an integral part of the global sustainability agenda. Guidelines for deriving globally applicable, life cycle based indicators are required to consistently quantify toxicity impacts from chemical emissions as well as from chemicals in consumer products. In response, we elaborate the methodological framework and present recommendations for advancing near-field/far-field exposure and toxicity characterization, and for implementing these recommendations in the scientific consensus model USEtox.

METHODS

An expert taskforce was convened by the Life Cycle Initiative hosted by UN Environment to expand existing guidance for evaluating human toxicity impacts from exposure to chemical substances. This taskforce evaluated advances since the original release of USEtox. Based on these advances, the taskforce identified two major aspects that required refinement, namely integrating near-field and far-field exposure and improving human dose-response modeling. Dedicated efforts have led to a set of recommendations to address these aspects in an update of USEtox, while ensuring consistency with the boundary conditions for characterizing life cycle toxicity impacts and being aligned with recommendations from agencies that regulate chemical exposure. The proposed framework was finally tested in an illustrative rice production and consumption case study.

RESULTS AND DISCUSSION

On the exposure side, a matrix system is proposed and recommended to integrate far-field exposure from environmental emissions with near-field exposure from chemicals in various consumer product types. Consumer exposure is addressed via submodels for each product type to account for product characteristics and exposure settings. Case study results illustrate that product-use related exposure dominates overall life cycle exposure. On the effect side, a probabilistic dose-response approach combined with a decision tree for identifying reliable points of departure is proposed for non-cancer effects, following recent guidance from the World Health Organization. This approach allows for explicitly considering both uncertainty and human variability in effect factors. Factors reflecting disease severity are proposed to distinguish cancer from non-cancer effects, and within the latter discriminate reproductive/developmental and other non-cancer effects. All proposed aspects have been consistently implemented into the original USEtox framework.

CONCLUSIONS

The recommended methodological advancements address several key limitations in earlier approaches. Next steps are to test the new characterization framework in additional case studies and to close remaining research gaps. Our framework is applicable for evaluating chemical emissions and product-related exposure in life cycle assessment, chemical alternatives assessment and chemical substitution, consumer exposure and risk screening, and high-throughput chemical prioritization.

Environmental damage cost assessment from municipal solid waste treatment based on LIME3 model

Environmental damage cost can measure the impact of pollution caused by human activity on final safeguard subjects from endpoint perspective. Application of environmental damage cost to municipal solid waste (MSW) management is still rare. To fill such a research gap, this study established a MSW environmental damage cost assessment method using Life Cycle Impact Assessment Method based on Endpoint (LIME) model. Four types of environmental damage cost, namely, primary productivity, social assets, biodiversity and human health for waste treatment were investigated in the city of Shanghai. Results show that the environmental damage cost was 113.7, 116.9, 140.0, 144.0 and 170.8 million dollars in Shanghai from 2014 to 2018, respectively. Damage cost of social assets was the dominant component, accounting for about 55%. Landfill mainly caused social assets damage cost, while incineration mainly caused human health damage cost. Scenarios analysis further revealed that after implementing MSW separation, the total environmental damage cost could be reduced by about 1/3. The best MSW treatment method is fermentation, followed by compost, incineration and landfill, with unit environmental damage cost being 0.22, 4.51, 16.04 and 23.47 USD/ton, respectively.

Integrating endocrine-related health effects into comparative human toxicity characterization

Endocrine-disrupting chemicals have the ability to interfere with and alter functions of the hormone system, leading to adverse effects on reproduction, growth and development. Despite growing concerns over their now ubiquitous presence in the environment, endocrine-related human health effects remain largely outside of comparative human toxicity characterization frameworks as applied for example in life cycle impact assessments. In this paper, we propose a new methodological framework to consistently integrate endocrine-related health effects into comparative human toxicity characterization. We present two quantitative and operational approaches for extrapolating towards a common point of departure from both in vivo and dosimetry-adjusted in vitro endocrine-related effect data and deriving effect factors as well as corresponding characterization factors for endocrine-active/endocrine-disrupting chemicals. Following the proposed approaches, we calculated effect factors for 323 chemicals, reflecting their endocrine potency, and related characterization factors for 157 chemicals, expressing their relative endocrine-related human toxicity potential. Developed effect and characterization factors are ready for use in the context of chemical prioritization and substitution as well as life cycle impact assessment and other comparative assessment frameworks. Endocrine-related effect factors were found comparable to existing effect factors for cancer and non-cancer effects, indicating that (1) the chemicals' endocrine potency is not necessarily higher or lower than other effect potencies and (2) using dosimetry-adjusted effect data to derive effect factors does not consistently overestimate the effect of potential endocrine disruptors. Calculated characterization factors span over 8-11 orders of magnitude for different substances and emission compartments and are dominated by the range in endocrine potencies.

Evaluation of sector-specific AWARE characterization factors for water scarcity footprint of electricity generation

Life Cycle Impact Assessment (LCIA) links the emissions and resource abstractions of a product system or process to potential impacts on the environment through characterization factors (CF). For regionalized impact categories like water-use, the regional CFs can vary over several orders of magnitude within the same country. The aggregated country-level CF, often used in LCIA, represents an average of local CF weighted by the local water consumption of all (or most) human water use including water use by all (or most) economic sectors. There is, however, great variability in spatio-temporal distribution of human water consumption across different industries. This study provides industry-specific water-use CFs for the electricity sector across the US. Our analysis shows that for electricity generation, the use of all-sector aggregated water-use CF would lead to an underestimation of impact scores compared to industry-specific CFs, by two folds. Even within the electricity sector, for two of the major subsectors, electricity based on natural gas and hydroelectricity, the country-level CFs can be significantly different due to the geographic distribution of powerplants. Our findings signify that the use of industry-specific CF can have a high influence in LCIA, especially for impact categories, such as water-use, with great spatio-temporal heterogeneity.

Modeling spatially resolved characterization factors for eutrophication potential in life cycle assessment

PURPOSE

Prior versions of the Tool for Reduction and Assessment of Chemical and other environmental Impacts (TRACI) have recognized the need for spatial variability when characterizing eutrophication. However, the method's underlying environmental models had not been updated to reflect the latest science. This new research provides the ability to differentiate locations with a high level of detail within the USA and provides global values at the country level.

METHODS

In previous research (Morelli et al. 2018), the authors reviewed a broad range of domain-specific models and life cycle assessment methods for characterization of eutrophication and ranked these by levels of importance to the field and readiness for further development. The current research is rooted in the decision outcome of Morelli et al. (2018) to separate freshwater and marine eutrophication to allow for the most tailored characterization of each category individually. The current research also assumes that freshwater systems are limited by phosphorus and marine systems are limited by nitrogen. Using a combination of spatial modeling methods for soil, air, and water, we calculate midpoint characterization factors for freshwater and marine eutrophication categories and evaluate the results through a US-based case application.

RESULTS AND DISCUSSION

Maps of the nutrient inventories, characterization factors, and overall impacts of the case application illustrate the spatial variation and patterns in the results. The importance of variation in geographic location is demonstrated using nutrient-based activity likelihood categories of agricultural (rural fertilizer), non-agricultural (urban fertilizer), and general (human waste processing). Proximity to large bodies of water, as well as individual hydraulic residence times, was shown to affect the comparative values of characterization factors across the USA.

CONCLUSIONS

In this paper, we have calculated and applied finely resolved freshwater and marine eutrophication characterization factors for the USA and country-level factors for the rest of the globe. Additional research is needed to provide similarly resolved characterization factors for the entire globe, which would require expansion of publicly available data and further development of applicable fate and transport models. Further scientific advances may also be considered as computing capabilities become more sophisticated and widely accessible.

Characterizing honey bee exposure and effects from pesticides for chemical prioritization and life cycle assessment

Agricultural pesticides are key contributors to pollinator decline worldwide. However, methods for quantifying impacts associated with pollinator exposure to pesticides are currently missing in comparative risk screening, chemical substitution and prioritization, and life cycle impact assessment methods. To address this gap, we developed a method for quantifying pesticide field exposure and ecotoxicity effects of honey bees as most economically important pollinator species worldwide. We defined bee intake and dermal contact fractions representing respectively oral and dermal exposure per unit mass applied, and tested our model on two pesticides applied to oilseed rape. Our results show that exposure varies between types of forager bees, with highest dermal contact fraction of 59 ppm in nectar foragers for lambda-cyhalothrin (insecticide), and highest oral intake fractions of 32 and 190 ppm in nectar foragers for boscalid (fungicide) and lambda-cyhalothrin, respectively. Hive oral exposure is up to 115 times higher than forager oral exposure. Combining exposure with effect estimates yields impacts, which are three orders of magnitude higher for the insecticide. Overall, nectar foragers are the most affected forager type for both pesticides, dominated by oral exposure. Our framework constitutes an important step toward integrating pollinator impacts in chemical substitution and life cycle impact assessment, and should be expanded to cover all relevant pesticide-crop combinations.

Spatial-temporal characteristics and driving factors of the human health impacts of five industrial aquatic toxic metals in China

With the rapid advancement of industrialization without effective supervision, industrial aquatic toxic metal (TM) emissions pose threats to human health in China. Due to differences in socioeconomic development, the regional disparity of industrial aquatic TM emissions is obvious nationwide. In this study, the human health impacts (HHIs) of industrial aquatic TM emissions (i.e., mercury (Hg), cadmium (Cd), hexavalent chromium (Cr(VI)), lead (Pb), and arsenic (As)) in the 31 provinces of China were evaluated based on the ReCiPe method, and the driving factors affecting HHIs from 2000 to 2015 were decomposed using the logarithmic mean Divisia index (LMDI) method. The results showed that the HHIs gradually decreased, with more than an 80% decrease from 2000 to 2015. The order of the TMs contributing to the national HHIs in 2015 was as follows: As (79.5%) > Cr(VI) (19.6%) > Hg (0.4%) > Pb (0.2%) = Cd (0.2%), and 21 (68%) provinces were dominated by industrial aquatic As emissions. Economic development is the major driving factor of the increase in HHIs, while the HHI strength and wastewater discharge intensity are the key driving factors causing reductions in the HHIs. Hunan, Inner Mongolia, Hubei, and Jiangxi accounted for approximately 55% of the total HHIs in 2015. Some suggestions for reducing HHIs based on the local realities of different provinces were put proposed considering two aspects: economic strategy and technical capability.

Extrapolation Factors for Characterizing Freshwater Ecotoxicity Effects

Various environmental and chemical assessment frameworks including ecological risk assessment and life cycle impact assessment aim at evaluating long-term ecotoxicity effects. Chronic test data are reported under the European Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation for various chemicals. However, chronic data are missing for a large fraction of marketed chemicals, for which acute test results are often available. Utilizing acute data requires robust extrapolation factors across effect endpoints, exposure durations, and species groups. We propose a decision tree based on strict criteria for curating and selecting high-quality aquatic ecotoxicity information available in REACH for organic chemicals, to derive a consistent set of generic and species group-specific extrapolation factors. Where ecotoxicity effect data are not available at all, we alternatively provide extrapolations from octanol-water partitioning coefficients as suitable predictor for chemicals with nonpolar narcosis as mode of action. Extrapolation factors range from 0.2 to 7 and are higher when simultaneously extrapolating across effect endpoints and exposure durations. Our results are consistent with previously reported values, while considering more endpoints, providing species group-specific factors, and characterizing uncertainty. Our proposed decision tree can be adapted to curate information from additional data sources as well as data for other environments, such as sediment ecotoxicity. Our approach and robust extrapolation factors help to increase the substance coverage for characterizing ecotoxicity effects across chemical and environmental assessment frameworks. Environ Toxicol Chem 2019;38:2568-2582. © 2019 SETAC.

Performance evaluation of a decentralized wastewater treatment system in India

A Decentralized Wastewater Treatment System (DEWATS) provides an economically feasible and efficient wastewater treatment solution especially in developing countries. It has an enormous potential for developing a sustainable environmental sanitation system. In this study, the treatment efficiency of eight DEWATS plants was evaluated in the state of Maharashtra, India, for their performance in terms of selected physico-chemical parameters of the wastewater. Although the efficiency of some of the plants was lower than that reported in literature, the effluent quality of all the plants was within the permissible discharge limits of the Central Pollution Control Board for all the parameters. Comprehensive assessment of Plant I was carried in terms of its technical and socio-economic aspects. Moreover, LCA tool has been utilized to evaluate the environmental impacts of the operation stage of DEWATS. The midpoint, CML 2001 (April 2015) methodology was adopted, in which 11 impact categories were considered. From the life cycle impact assessment and interpretation, the main impacts are identified as releases of COD, P-PO₄^3-, and N-NH₄⁺ to water bodies and disposal of sludge. Due to negligible energy consumption, the operation stage was found to be less damaging to the environment. It was concluded that DEWATS can be a good alternative for treating wastewater with negligible energy and chemical consumption.

Pollution levels of stormwater discharges and resulting environmental impacts

Stormwater carries pollutants that potentially cause negative environmental impacts to receiving water bodies, which can be quantified using life cycle impact assessment (LCIA). We compiled a list of 20 metals, almost 300 organic compounds, and nutrients potentially present in stormwater, and measured concentrations reported in literature. We calculated mean pollutant concentrations, which we then translated to generic impacts per litre of stormwater discharged, using existing LCIA characterisation factors. Freshwater and marine ecotoxicity impacts were found to be within the same order of magnitude (0.72, and 0.82 CTUe/l respectively), while eutrophication impacts were 3.2E-07 kgP-eq/l for freshwater and 2.0E-06 kgN-eq/l for marine waters. Stormwater discharges potentially have a strong contribution to ecotoxicity impacts compared to other human activities, such as human water consumption and agriculture. Conversely, contribution to aquatic eutrophication impacts was modest. Metals were identified as the main contributor to ecotoxicity impacts, causing >97% of the total impacts. This is in line with conclusions from a legal screening, where metals showed to be problematic when comparing measured concentrations against existing environmental quality standards.

Resource and environmental impacts of using second-hand laptop computers: A case study of commercial reuse

The circular economy is proposed to reduce environmental impact, but as yet, there is limited empirical evidence of this sort from studying real, commercial circular economy business cases. This study investigates the environmental impacts of using second-hand laptops, mediated by a commercial reuse operation, instead of new ones. The method used is life cycle assessment (LCA) and special attention is given to laptops' metal resource use by using several complementary life cycle impact assessment methods. The results show that all activities required to enable reuse of laptops are negligible, despite the reuse company's large geographical scope. Two principal features of reuse reduce environmental impacts. Firstly, use extension reduces all impacts considerably since there are large embedded impacts in components. Secondly, the reuse company steers non-reusable laptops into state-of-the-art recycling. This provides additional impact reductions, especially with regards to toxicity and metal resource use. The results for metal resource use however diverge between LCIA methods in terms of highlighted metals which, in turn, affects the degree of impact reduction. LCIA methods that characterise functionally recycled metals as important, result in larger impact reduction, since these emphasise the merits of steering flows into state-of-the-art recycling. The study thus demonstrates how using second-hand laptops, mediated by a commercial reuse operation, compared to new ones, in practice, reduces different types of environmental impact through synergistic relationships between reuse and recycling. Moreover, it illustrates how the choice of LCIA method can influence interpretations of metal resource use impacts when applying circular economy measures to information and communication technologies (ICT).

Global warming potential and total material requirement in metal production: Identification of changes in environmental impact through metal substitution

In view of the increasing demand for metal use, it is of significant importance to evaluate the environmental impact of metal production. The global warming potential (GWP) in the process of metal production has often been focused upon as a major indicator for evaluating the burden on the environment. Moreover, the environmental impact and mineral exploitation arising from metal ore mining activities, which generate unavoidable mine wastes and have an impact on the ecological biodiversity, cannot be ignored. The major factors for determining the intensity of resource exploitation being the ore grades and strip ratio, the existing indicators for land use employed in the life cycle assessment (LCA) may not fully cover the criteria of the impact of metal mining on the environmental system. Therefore, this study employs the method of total material requirement (TMR) assessment, involving not only the direct and indirect material inputs but also the hidden flows, which are particularly associated with mine wastes. Firstly, the methodology of computing the TMR in the process of metal production is developed. Next, the relation between the GWP and TMR for 58 metals is assessed and finally, the environmental impact through metal substitutes is evaluated from the perspectives of the GWP and TMR. This analysis could identify some of the aspects overlooked in the previous environmental criteria that were concentrating on greenhouse gas emissions and global warming. The developed algorithm may be useful in identifying appropriate metal substitutes, considering the environmental impact.

Impact assessment of energy utilization in agriculture for India and Pakistan

Sustainable food production is a key concern across countries in South Asia. Most assessments of sustainable agriculture in this region focus on the availability and affordability of resource inputs. However, studies accounting for environmental footprint of agricultural activities in South Asian countries are limited in the existing literature. This paper analyzed the environmental impact of energy utilization in agriculture in India and Pakistan. More specifically, the study analyzes the trends of fuel and electricity consumption for crop production in these countries during a ten-year period between the years 2002 and 2011. Life cycle impact assessment categories including global warming potential, human toxicity, acidification and eutrophication were used to holistically analyze the end-user impact of energy consumption. Results indicated an increase in these impacts for both countries during the study period. On a per hectare basis, the assessed impacts were relatively greater in India than in Pakistan during the study period. The main reason behind larger impacts in India was its significantly greater use of coal for electricity generation. Overall, this study showed that further electrification of agriculture will not necessarily lead to cleaner environment in these countries. Due to high population growth rates, energy consumption for agriculture is expected to grow in these countries in the future. Unless cleaner sources of electricity are used, further energy intensification in agriculture will be detrimental to ecosystem and human health, which in turn will be counterproductive for sustainable agriculture.

Modeling pharmaceutical emissions and their toxicity-related effects in life cycle assessment (LCA): A review

Over the last few decades, worldwide detection of active pharmaceutical ingredients (APIs) in aquatic environments and the associated toxicological effects on wildlife and human health have become a matter of public and scientific debate. While life cycle assessment (LCA) and life cycle impact assessment (LCIA) models are increasingly used to assess the potential eco- and human-toxicological effects of chemical emissions, few studies have looked into the issue of modeling pharmaceutical emissions specifically and their toxicity-related effects in an LCA context. This paper reviews the state of the art to inventory and characterize API emissions in LCA with the goal to identify relevant gaps and challenges. A search for 208 environmentally relevant APIs in 2 life cycle inventory (LCI) databases revealed a meager representation of this group of chemicals. Similarly, the LCIA model USEtox was found to include characterization factors (CFs) for less than 60 APIs. First approaches to model API emissions in LCA were identified on the basis of an examination of 40 LCA case studies in the pharmaceutical sector and in the field of wastewater treatment. Moreover, CFs for 79 additional APIs, expressing their ecotoxicity and/or human toxicity potential, were gathered from literature. An analysis of the variability of API-CFs in different LCIA models showed a variation of about 2-3 orders of magnitude. Based on the review results, 3 main gaps in the modeling and characterization of API emissions in an LCA context were identified: (1) incomplete modeling of API flows and API emissions along the life cycle of human pharmaceuticals, especially during their use and end-of-life phase, (2) limited API coverage in existing LCIA toxicity models, and (3) missing pharma-specific impact pathways (e.g., endocrine disruption and antibiotic resistance) in existing LCIA models. Recommendations to tackle these gaps are provided, and priority action steps are discussed. Integr Environ Assess Manag 2019;15:6-18. © 2018 SETAC.

Defining freshwater as a natural resource: A framework linking water use to the area of protection natural resources

PURPOSE

While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address impacts to natural resources for future generations. This framework aims to (1) define freshwater resource as an item to protect within the Area of Protection (AoP) natural resources, (2) identify relevant impact pathways affecting freshwater resources, and (3) outline methodological choices for impact characterization model development.

METHOD

Considering the current scope of the AoP natural resources, the complex nature of freshwater resources and its important dimensions to safeguard safe future supply, a definition of freshwater resource is proposed, including water quality aspects. In order to clearly define what is to be protected, the freshwater resource is put in perspective through the lens of the three main safeguard subjects defined by Dewulf et al. (2015). In addition, an extensive literature review identifies a wide range of possible impact pathways to freshwater resources, establishing the link between different inventory elementary flows (water consumption, emissions and land use) and their potential to cause long-term freshwater depletion or degradation.

RESULTS AND DISCUSSION

Freshwater as a resource has a particular status in LCA resource assessment. First, it exists in the form of three types of resources: flow, fund, or stock. Then, in addition to being a resource for human economic activities (e.g. hydropower), it is above all a non-substitutable support for life that can be affected by both consumption (source function) and pollution (sink function). Therefore, both types of elementary flows (water consumption and emissions) should be linked to a damage indicator for freshwater as a resource. Land use is also identified as a potential stressor to freshwater resources by altering runoff, infiltration and erosion processes as well as evapotranspiration. It is suggested to use the concept of recovery period to operationalize this framework: when the recovery period lasts longer than a given period of time, impacts are considered to be irreversible and fall into the concern of freshwater resources protection (i.e. affecting future generations), while short-term impacts effect the AoP ecosystem quality and human health directly. It is shown that it is relevant to include this concept in the impact assessment stage in order to discriminate the long-term from the short-term impacts, as some dynamic fate models already do.

CONCLUSION

This framework provides a solid basis for the consistent development of future LCIA methods for freshwater resources, thereby capturing the potential long-term impacts that could warn decision makers about potential safe water supply issues in the future.

Toward harmonizing ecotoxicity characterization in life cycle impact assessment

Ecosystem quality is an important area of protection in life cycle impact assessment (LCIA). Chemical pollution has adverse impacts on ecosystems on a global scale. To improve methods for assessing ecosystem impacts, the Life Cycle Initiative hosted by the United Nations Environment Programme established a task force to evaluate the state-of-the-science in modeling chemical exposure of organisms and the resulting ecotoxicological effects for use in LCIA. The outcome of the task force work will be global guidance and harmonization by recommending changes to the existing practice of exposure and effect modeling in ecotoxicity characterization. These changes will reflect the current science and ensure the stability of recommended practice. Recommendations must work within the needs of LCIA in terms of 1) operating on information from any inventory reporting chemical emissions with limited spatiotemporal information, 2) applying best estimates rather than conservative assumptions to ensure unbiased comparison with results for other impact categories, and 3) yielding results that are additive across substances and life cycle stages and that will allow a quantitative expression of damage to the exposed ecosystem. We describe the current framework and discuss research questions identified in a roadmap. Primary research questions relate to the approach toward ecotoxicological effect assessment, the need to clarify the method's scope and interpretation of its results, the need to consider additional environmental compartments and impact pathways, and the relevance of effect metrics other than the currently applied geometric mean of toxicity effect data across species. Because they often dominate ecotoxicity results in LCIA, we give metals a special focus, including consideration of their possible essentiality and changes in environmental bioavailability. We conclude with a summary of key questions along with preliminary recommendations to address them as well as open questions that require additional research efforts. Environ Toxicol Chem 2018;37:2955-2971. © 2018 SETAC.

Are stormwater pollution impacts significant in life cycle assessment? A new methodology for quantifying embedded urban stormwater impacts

Current life cycle assessment (LCA) models do not explicitly incorporate the impacts from urban stormwater pollution. To address this issue, a framework to estimate the impacts from urban stormwater pollution over the lifetime of a system has been developed, laying the groundwork for subsequent improvements in life cycle databases and LCA modelling. The proposed framework incorporates urban stormwater event mean concentration (EMC) data into existing LCA impact categories to account for the environmental impacts associated with urban land occupation across the whole life cycle of a system. It consists of five steps: (1) compilation of inventory of urban stormwater pollutants; (2) collection of precipitation data; (3) classification and characterisation within existing midpoint impact categories; (4) collation of inventory data for impermeable urban land occupation; and (5) impact assessment. The framework is generic and can be applied to any system using any LCA impact method. Its application is demonstrated by two illustrative case studies: electricity generation and production of construction materials. The results show that pollutants in urban stormwater have an influence on human toxicity, freshwater and marine ecotoxicity, marine eutrophication, freshwater eutrophication and terrestrial ecotoxicity. Among these, urban stormwater pollution has the highest relative contribution to the eutrophication potentials. The results also suggest that stormwater pollution from urban areas can have a substantial effect on the life cycle impacts of some systems (construction materials), while for some systems the effect is small (e.g. electricity generation). However, it is not possible to determine a priori which systems are affected so that the impacts from stormwater pollution should be considered routinely in future LCA studies. The paper also proposes ways to incorporate stormwater pollution burdens into the life cycle databases.

How to bring absolute sustainability into decision-making: An industry case study using a Planetary Boundary-based methodology

The Planetary Boundaries concept has emerged as a framework for articulating environmental limits, gaining traction as a basis for considering sustainability in business settings, government policy and international guidelines. There is emerging interest in using the Planetary Boundaries concept as part of life cycle assessment (LCA) for gauging absolute environmental sustainability. We tested the applicability of a novel Planetary Boundaries-based life cycle impact assessment methodology on a hypothetical laundry washing case study at the EU level. We express the impacts corresponding to the control variables of the individual Planetary Boundaries together with a measure of their respective uncertainties. We tested four sharing principles for assigning a share of the safe operating space (SoSOS) to laundry washing and assessed if the impacts were within the assigned SoSOS. The choice of sharing principle had the greatest influence on the outcome. We therefore highlight the need for more research on the development and choice of sharing principles. Although further work is required to operationalize Planetary Boundaries in LCA, this study shows the potential to relate impacts of human activities to environmental boundaries using LCA, offering company and policy decision-makers information needed to promote environmental sustainability.

The potential ecotoxicological impact of pharmaceutical and personal care products on humans and freshwater, based on USEtox™ characterization factors. A Spanish case study of toxicity impact scores

Pharmaceutical and personal care products (PPCPs) are being increasingly included in Life Cycle Assessment studies (LCAs) since they have brought into evidence both human and ecological adverse effects due to their presence in different environmental compartments, wastewater facilities and industry. Therefore, the main goal of this research was to estimate the characterization factors (CFs) of 27 PPCPs widely used worldwide in order to incorporate their values into Life Cycle Impact Assessment studies (LCIA) or to generate a toxicity impact score ranking. Physicochemical properties, degradation rates, bioaccumulation, ecotoxicity and human health effects were collected from experimental data, recognized databases or estimated using EPI Suite™ and the USEtox™ software, and were subsequently used for estimating CFs. In addition, a Spanish toxicity impact score ranking was carried out for 49 PPCPs using the 27 newly calculated CFs, and 22 CFs already available in the literature, besides the data related to the occurrence of PPCPs in the environment in Spain. It has been highlighted that emissions into the continental freshwater compartment showed the highest CFs values for human effects (ranging from 10^-9 to 10^-3Cases·kg^-1), followed by emissions into the air (10^-9 to 10^-5Cases·kg^-1), soil (10^-11 to 10⁵Cases·kg^-1) and seawater (10^-12 to 10^-4Cases·kg^-1). CFs regarding the affectation of freshwater aquatic environments were the highest of those proceeding from emissions into continental freshwater (between 1 to 10⁴PAF·m³·day·kg_emission^-1) due to the direct contact between the source of emission and the compartment affected, followed by soil (among 10^-1 to 10⁴PAF·m³·day·kg_emission^-1), and air (among 10^-2 to 10⁴PAF·m³·day·kg_emission^-1) while the lowest were the CFs of continental seawater (among 10^-28 to 10^-3PAF·m³·day·kg_emission^-1). Freshwater aquatic ecotoxicological CFs are much higher than human toxicity CFs, demonstrating that the ecological impact of PPCPs in aquatic environments must be a matter of urgent attention. According to the Spanish toxicity impact score calculated, the PPCPs with the highest impact are hormones, antidepressants, fragrances, antibiotics, angiotensin receptor blockers and blood lipid regulators, which have already been found in other kinds of score rankings. These results, which were not available until now, will be useful in order to perform better LCIA studies, incorporating the micro-pollutants whose CFs have been estimated, or in order to carry out single hazard/risk environmental impact assessments.

LCIA framework and cross-cutting issues guidance within the UNEP-SETAC Life Cycle Initiative

Increasing needs for decision support and advances in scientific knowledge within life cycle assessment (LCA) led to substantial efforts to provide global guidance on environmental life cycle impact assessment (LCIA) indicators under the auspices of the UNEP-SETAC Life Cycle Initiative. As part of these efforts, a dedicated task force focused on addressing several LCIA cross-cutting issues as aspects spanning several impact categories, including spatiotemporal aspects, reference states, normalization and weighting, and uncertainty assessment. Here, findings of the cross-cutting issues task force are presented along with an update of the existing UNEP-SETAC LCIA emission-to-damage framework. Specific recommendations are provided with respect to metrics for human health (Disability Adjusted Life Years, DALY) and ecosystem quality (Potentially Disappeared Fraction of species, PDF). Additionally, we stress the importance of transparent reporting of characterization models, reference states, and assumptions, in order to facilitate cross-comparison between chosen methods and indicators. We recommend developing spatially regionalized characterization models, whenever the nature of impacts shows spatial variability and related spatial data are available. Standard formats should be used for reporting spatially differentiated models, and choices regarding spatiotemporal scales should be clearly communicated. For normalization, we recommend using external normalization references. Over the next two years, the task force will continue its effort with a focus on providing guidance for LCA practitioners on how to use the UNEP-SETAC LCIA framework as well as for method developers on how to consistently extend and further improve this framework.

The life cycle impact for platinum group metals and lithium to 2070 via surplus cost potential

PURPOSE

A surplus cost potential (SCP) indicator has been developed as a measure of resource scarcity in the life cycle impact assessment (LCIA) context. To date, quality SCP estimates for other minerals than fossils are either not yet available or suffer methodological and data limitations. This paper overcomes these limitations and demonstrate how SCP estimates for metals can be calculated without the utilisation of ore grade function and by collecting primary economic and geological data.

METHODS

Data were collected in line with the geographical distribution, mine type, deposit type and production volumes and total production costs in order to construct cost-cumulative availability curves for platinum group metals (PGMs) and lithium. These curves capture the total amount of known mineral resources that can be recovered profitably at various prices from different types of mineral deposits under current conditions (this is, current technology, prevailing labour and other input prices). They served as a basis for modelling the marginal cost increase, a necessary parameter for estimating the SCP indicator. Surplus costs were calculated for different scenario projections for future mineral production considering future market dynamics, recyclability rates, demand-side technological developments and economic growth and by applying declining social discount rate.

RESULTS AND DISCUSSION

Surplus costs were calculated for three mineral production scenarios, ranging from (US$₂₀₁₄/kg) 6545-8354 for platinum, 3583-4573 for palladium, 8281-10,569 for rhodium, 513-655 for ruthenium, 3201-4086 for iridium and 1.70-5.80 for lithium. Compared with the current production costs, the results indicate that problematic price increases of lithium are unlikely if the latest technological trends in the automotive sector will continue up to 2070. Surplus costs for PGMs are approximately one-third of the current production costs in all scenarios; hence, a threat of their price increases by 2070 will largely depend on the discovery of new deposits and the ability of new technologies to push these costs down over time. This also applies to lithium if the increasing electrification of road transport will continue up to 2070.

CONCLUSIONS

This study provides useful insight into the availability of PGMs and lithium up to 2070. It proves that if time and resources permit, reliable surplus cost estimates can be calculated, at least in the short-run, based on the construction of one's own curves with the level of quality comparable to expert-driven consulting services. Modelling and incorporating unknown deposits and potential future mineral production costs into these curves is the subject of future work.

A framework for an alternatives assessment dashboard for evaluating chemical alternatives applied to flame retardants for electronic applications

The goal of alternatives assessment (AA) is to facilitate a comparison of alternatives to a chemical of concern, resulting in the identification of safer alternatives. A two stage methodology for comparing chemical alternatives was developed. In the first stage, alternatives are compared using a variety of human health effects, ecotoxicity, and physicochemical properties. Hazard profiles are completed using a variety of online sources and quantitative structure activity relationship models. In the second stage, alternatives are evaluated utilizing an exposure/risk assessment over the entire life cycle. Exposure values are calculated using screening-level near-field and far-field exposure models. The second stage allows one to more accurately compare potential exposure to each alternative and consider additional factors that may not be obvious from separate binned persistence, bioaccumulation, and toxicity scores. The methodology was utilized to compare phosphate-based alternatives for decabromodiphenyl ether (decaBDE) in electronics applications.

Exploring REACH as a potential data source for characterizing ecotoxicity in life cycle assessment

Toxicity models in life cycle impact assessment (LCIA) currently only characterize a small fraction of marketed substances, mostly because of limitations in the underlying ecotoxicity data. One approach to improve the current data situation in LCIA is to identify new data sources, such as the European Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) database. The present study explored REACH as a potential data source for LCIA based on matching reported ecotoxicity data for substances that are currently also included in the United Nations Environment Programme/Society for Environmental Toxicology and Chemistry (UNEP/SETAC) scientific consensus model USEtox for characterizing toxicity impacts. Data are evaluated with respect to number of data points, reported reliability, and test duration, and are compared with data listed in USEtox at the level of hazardous concentration for 50% of the covered species per substance. The results emphasize differences between data available via REACH and in USEtox. The comparison of ecotoxicity data from REACH and USEtox shows potential for using REACH ecotoxicity data in LCIA toxicity characterization, but also highlights issues related to compliance of submitted data with REACH requirements as well as different assumptions underlying regulatory risk assessment under REACH versus data needed for LCIA. Thus, further research is required to address data quality, pre-processing, and applicability, before considering data submitted under REACH as a data source for use in LCIA, and also to explore additionally available data sources, published studies, and reports. Environ Toxicol Chem 2017;36:492-500. © 2016 SETAC.

A review of models for near-field exposure pathways of chemicals in consumer products

Exposure to chemicals in consumer products has been gaining increasing attention, with multiple studies showing that near-field exposures from products is high compared to far-field exposures. Regarding the numerous chemical-product combinations, there is a need for an overarching review of models able to quantify the multiple transfers of chemicals from products used near-field to humans. The present review therefore aims at an in-depth overview of modeling approaches for near-field chemical release and human exposure pathways associated with consumer products. It focuses on lower-tier, mechanistic models suitable for life cycle assessments (LCA), chemical alternative assessment (CAA) and high-throughput screening risk assessment (HTS). Chemicals in a product enter the near-field via a defined "compartment of entry", are transformed or transferred to adjacent compartments, and eventually end in a "human receptor compartment". We first focus on models of physical mass transfers from the product to 'near-field' compartments. For transfers of chemicals from article interior, adequate modeling of in-article diffusion and of partitioning between article surface and air/skin/food is key. Modeling volatilization and subsequent transfer to the outdoor is crucial for transfers of chemicals used in the inner space of appliances, on object surfaces or directly emitted to indoor air. For transfers from skin surface, models need to reflect the competition between dermal permeation, volatilization and fraction washed-off. We then focus on transfers from the 'near-field' to 'human' compartments, defined as respiratory tract, gastrointestinal tract and epidermis, for which good estimates of air concentrations, non-dietary ingestion parameters and skin permeation are essential, respectively. We critically characterize for each exposure pathway the ability of models to estimate near-field transfers and to best inform LCA, CAA and HTS, summarizing the main characteristics of the potentially best-suited models. This review identifies large knowledge gaps for several near-field pathways and suggests research needs and future directions.

Indoor inhalation intake fractions of fine particulate matter: review of influencing factors

Exposure to fine particulate matter (PM_2.5 ) is a major contributor to the global human disease burden. The indoor environment is of particular importance when considering the health effects associated with PM_2.5 exposures because people spend the majority of their time indoors and PM_2.5 exposures per unit mass emitted indoors are two to three orders of magnitude larger than exposures to outdoor emissions. Variability in indoor PM_2.5 intake fraction (iF_in,total ), which is defined as the integrated cumulative intake of PM_2.5 per unit of emission, is driven by a combination of building-specific, human-specific, and pollutant-specific factors. Due to a limited availability of data characterizing these factors, however, indoor emissions and intake of PM_2.5 are not commonly considered when evaluating the environmental performance of product life cycles. With the aim of addressing this barrier, a literature review was conducted and data characterizing factors influencing iF_in,total were compiled. In addition to providing data for the calculation of iF_in,total in various indoor environments and for a range of geographic regions, this paper discusses remaining limitations to the incorporation of PM_2.5 -derived health impacts into life cycle assessments and makes recommendations regarding future research.

The challenges of including impacts on biodiversity in agricultural life cycle assessments

Agriculture is considered to be one of the main drivers for worldwide biodiversity loss but the impacts of agricultural production on biodiversity have not been extensively considered in Life Cycle Assessments (LCAs). Recent realisation that biodiversity impact should be included in comprehensive LCAs has led to attempts to develop and implement methods for biodiversity impact assessment. In this review, twenty-two different biodiversity impact assessment methods have been analysed to identify their strengths and weaknesses in terms of their comprehensiveness in the evaluation of agricultural products. Different criteria, which had to meet the specific requirements of biodiversity research, life cycle assessment methodology, and the evaluation of agricultural products, were selected to investigate the identified methods. Very few of the methods were developed with the specific intention of being used for agricultural LCAs. Furthermore, none of the methods can be applied globally while at the same time being able to differentiate between various agricultural intensities. Global value chains and the increasing awareness of different biodiversity impacts of agricultural production systems demand the development of evaluation methods that are able to overcome these shortcomings. Despite the progress that has already been achieved, there are still unresolved difficulties which need further research and improvement.

Coupled near-field and far-field exposure assessment framework for chemicals in consumer products

Humans can be exposed to chemicals in consumer products through product use and environmental emissions over the product life cycle. Exposure pathways are often complex, where chemicals can transfer directly from products to humans during use or exchange between various indoor and outdoor compartments until sub-fractions reach humans. To consistently evaluate exposure pathways along product life cycles, a flexible mass balance-based assessment framework is presented structuring multimedia chemical transfers in a matrix of direct inter-compartmental transfer fractions. By matrix inversion, we quantify cumulative multimedia transfer fractions and exposure pathway-specific product intake fractions defined as chemical mass taken in by humans per unit mass of chemical in a product. Combining product intake fractions with chemical mass in the product yields intake estimates for use in life cycle impact assessment and chemical alternatives assessment, or daily intake doses for use in risk-based assessment and high-throughput screening. Two illustrative examples of chemicals used in personal care products and flooring materials demonstrate how this matrix-based framework offers a consistent and efficient way to rapidly compare exposure pathways for adult and child users and for the general population. This framework constitutes a user-friendly approach to develop, compare and interpret multiple human exposure scenarios in a coupled system of near-field ('user' environment), far-field and human intake compartments, and helps understand the contribution of individual pathways to overall human exposure in various product application contexts to inform decisions in different science-policy fields for which exposure quantification is relevant.

Evolution of electronic waste toxicity: Trends in innovation and regulation

Rapid innovation in printed circuit board, and the uncertainties surrounding quantification of the human and environmental health impacts of e-waste disposal have made it difficult to confirm the influence of evolving e-waste management strategies and regulatory policies on materials. To assess these influences, we analyzed hazardous chemicals in a market-representative set of Waste printed circuit boards (WPCBs, 1996-2010). We used standard leaching tests to characterize hazard potential and USEtox® to project impacts on human health and ecosystem. The results demonstrate that command-and-control regulations have had minimal impacts on WPCBs composition and toxicity risks; whereas technological innovation may have been influenced more by resource conservation, including a declining trend in the use of precious metals such as gold. WPCBs remain classified as hazardous under U.S. and California laws because of excessive toxic metals. Lead poses the most significant risk for cancers; zinc for non-cancer diseases; copper had the largest potential impact on ecosystem quality. Among organics, acenaphthylene, the largest risk for cancers; naphthalene for non-cancer diseases; pyrene has the highest potential for ecotoxicological impacts. These findings support the need for stronger enforcement of international policies and technology innovation to implement the strategy of design-for-the-environment and to encourage recovery, recycling, and reuse of WPCBs.

Development of Comparative Toxicity Potentials of 14 cationic metals in freshwater

Site-dependent and site-generic Comparative Toxicity Potentials (CTPs) (also known as Characterization Factors (CFs)) were calculated for 14 cationic metals (Al(III), Ba, Be, Cd, Co, Cr(III), Cs, Cu(II), Fe(II), Fe(III), Mn(II), Ni, Pb, Sr and Zn), to be applied in Life Cycle Impact Assessment. CTPs were calculated for 7 EU-archetypes, taking bioavailability and speciation pattern into account. The resulting site-dependent CTPs showed up to 2.4-6.5 orders of magnitude variation across archetypes for those metals that form stable hydroxyl compounds in slightly alkaline waters (Al(III), Be, Cr(III), Cu(II) and Fe(III)), emphasizing the importance of using site-dependent CTPs for these metals where possible. For the other metals, CTPs stayed within around 0.9 orders of magnitude, making spatial differentiation less important. In acidic waters (pH<6.4), Al(III) and Cu(II) had the highest CTPs, while Cd ranked highest in other waters. Based on the site-dependent CTPs, site-generic CTPs were developed applying different averaging principle. Emission weighted average of 7 EU-archetype CTPs was recommended as site-generic CTP for use in LCA studies, where receiving location is unclear. Compared to previous studies by Gandhi et al. (2010, 2011a), new site-dependent CTPs were similar or slightly higher for Cd, Co, Ni, Pb and Zn, but 1-2 orders of magnitude higher for Cu. Compared to the default site-generic CTPs in the frequently used characterization models USES-LCA and USEtox, new site-generic CTPs were mostly higher or similar, within up to ∼2 orders of magnitude difference.

Life Cycle Assessment for desalination: a review on methodology feasibility and reliability

As concerns of natural resource depletion and environmental degradation caused by desalination increase, research studies of the environmental sustainability of desalination are growing in importance. Life Cycle Assessment (LCA) is an ISO standardized method and is widely applied to evaluate the environmental performance of desalination. This study reviews more than 30 desalination LCA studies since 2000s and identifies two major issues in need of improvement. The first is feasibility, covering three elements that support the implementation of the LCA to desalination, including accounting methods, supporting databases, and life cycle impact assessment approaches. The second is reliability, addressing three essential aspects that drive uncertainty in results, including the incompleteness of the system boundary, the unrepresentativeness of the database, and the omission of uncertainty analysis. This work can serve as a preliminary LCA reference for desalination specialists, but will also strengthen LCA as an effective method to evaluate the environment footprint of desalination alternatives.

Emergy evaluation using the calculation software SCALE: case study, added value and potential improvements

This paper reports the emergy-based evaluation (EME) of the ecological performance of four water treatment plants (WTPs) using three different approaches. The results obtained using the emergy calculation software SCALE (EMESCALE) are compared with those achieved through a conventional emergy evaluation procedure (EMECONV), as well as through the application of the Solar Energy Demand (SED) method. SCALE's results are based on a detailed representation of the chain of technological processes provided by the lifecycle inventory database ecoinvent®. They benefit from a higher level of details in the description of the technological network as compared to the ones calculated with a conventional EME and, unlike the SED results, are computed according to the emergy algebra rules. The analysis delves into the quantitative comparison of unit emergy values (UEVs) for individual technospheric inputs provided by each method, demonstrating the added value of SCALE to enhance reproducibility, accurateness and completeness of an EME. However, SCALE cannot presently include non-technospheric inputs in emergy accounting, like e.g. human labor and ecosystem services. Moreover, SCALE is limited by the approach used to build the dataset of UEVs for natural resources. Recommendations on the scope and accuracy of SCALE-based emergy accounting are suggested for further steps in software development, as well as preliminary quantitative methods to account for ecosystem services and human labor.