Correction to "Prospective Life Cycle Assessment of Lithium-Sulfur Batteries for Stationary Energy Storage".

[This corrects the article DOI: 10.1021/acssuschemeng.3c00141.].

Proxy Measures for Simplified Environmental Assessment of Manufactured Nanomaterials.

Proxy measures have been proposed as a low-data option for simplified assessment of environmental threat given the high complexity of the natural environment. We here review studies of environmental release, fate, toxicity, and risk to identify relevant proxy measures for manufactured nanomaterials (MNMs). In total, 18 potential proxy measures were identified and evaluated regarding their link to environmental risk, an aspect of relevance, and data availability, an aspect of practice. They include socio-technical measures (e.g., MNM release), particle-specific measures (e.g., particle size), partitioning coefficients (e.g., the octanol-water coefficient), and other fate-related measures (e.g., half-life) as well as various ecotoxicological measures (e.g., 50% effect concentration). For most identified proxy measures, the link to environmental risk was weak and data availability low. Two exceptions were global production volume and ecotoxicity, for which the links to environmental risk are strong and data availability relatively decent. As proof of concept, these were employed to assess seven MNMs: titanium dioxide, cerium dioxide, zinc oxide, silver, silicon dioxide, carbon nanotubes, and graphene. The results show that none of the MNMs have both high production volumes and high ecotoxicity. Several refinements of the assessment are possible, such as higher resolution regarding the MNMs assessed (e.g., different allotropes) and different metrics (e.g., particle number and surface area). The proof of concept shows the feasibility of using proxy measures for environmental assessment of MNMs, in particular for novel MNMs in early technological development, when data is particularly scarce.

Live and Let Die? Life Cycle Human Health Impacts from the Use of Tire Studs.

Studded tires are used in a number of countries during winter in order to prevent accidents. The use of tire studs is controversial and debated because of human health impacts from increased road particle emissions. The aims of this study are to assess whether the use of tire studs in a Scandinavian studded passenger car actually avoids or causes health impacts from a broader life cycle perspective, and to assess the distribution of these impacts over the life cycle. Life cycle assessment is applied and the disability-adjusted life years indicator is used to quantify the following five types of health impacts: (1) impacts saved in the use phase, (2) particle emissions in the use phase, (3) production system emissions, (4) occupational accidents in the production system, and (5) conflict casualties from revenues of cobalt mining. The results show that the health benefits in the use phase in general are outweighed by the negative impacts during the life cycle. The largest contribution to these negative human health impacts are from use phase particle emissions (67⁻77%) and occupational accidents during artisanal cobalt mining (8⁻18%). About 23⁻33% of the negative impacts occur outside Scandinavia, where the benefits occur. The results inform the current debate and highlight the need for research on alternatives to tire studs with a positive net health balance.

A framework for energy use indicators and their reporting in life cycle assessment.

Energy use is a common impact category in life cycle assessment (LCA). Many different energy use indicators are used in LCA studies, accounting for energy use in different ways. Often, however, the choice behind which energy use indicator is applied is poorly described and motivated. To contribute to a more purposeful selection of energy use indicators and to ensure consistent and transparent reporting of energy use in LCA, a general framework for energy use indicator construction and reporting in LCA studies will be presented in this article. The framework differentiates between 1) renewable and nonrenewable energies, 2) primary and secondary energies, and 3) energy intended for energy purposes versus energy intended for material purposes. This framework is described both graphically and mathematically. Furthermore, the framework is illustrated through application to a number of energy use indicators that are frequently used in LCA studies: cumulative energy demand (CED), nonrenewable cumulative energy demand (NRCED), fossil energy use (FEU), primary fossil energy use (PFEU), and secondary energy use (SEU). To illustrate how the application of different energy use indicators may lead to different results, cradle-to-gate energy use of the bionanomaterial cellulose nanofibrils (CNF) is assessed using 5 different indicators and showing a factor of 3 differences between the highest and lowest results. The relevance of different energy use indicators to different actors and contexts will be discussed, and further developments of the framework are then suggested. Integr Environ Assess Manag 2016;12:429-436. © 2015 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC.

Life cycle assessment of cellulose nanofibrils production by mechanical treatment and two different pretreatment processes.

Nanocellulose is a bionanomaterial with many promising applications, but high energy use in production has been described as a potential obstacle for future use. In fact, life cycle assessment studies have indicated high life cycle energy use for nanocellulose. In this study, we assess the cradle-to-gate environmental impacts of three production routes for a particular type of nanocellulose called cellulose nanofibrils (CNF) made from wood pulp. The three production routes are (1) the enzymatic production route, which includes an enzymatic pretreatment, (2) the carboxymethylation route, which includes a carboxymethylation pretreatment, and (3) one route without pretreatment, here called the no pretreatment route. The results show that CNF produced via the carboxymethylation route clearly has the highest environmental impacts due to large use of solvents made from crude oil. The enzymatic and no pretreatment routes both have lower environmental impacts, of similar magnitude. A sensitivity analysis showed that the no pretreatment route was sensitive to the electricity mix, and the carboxymethylation route to solvent recovery. When comparing the results to those of other carbon nanomaterials, it was shown that in particular CNF produced via the enzymatic and no pretreatment routes had comparatively low environmental impacts.

Prospective life cycle assessment of graphene production by ultrasonication and chemical reduction.

One promising future bulk application of graphene is as composite additive. Therefore, we compare two production routes for in-solution graphene using a cradle-to-gate lifecycle assessment focusing on potential differences in energy use, blue water footprint, human toxicity, and ecotoxicity. The data used for the assessment is based on information in scientific papers and patents. Considering the prospective nature of this study, environmental impacts from background systems such as energy production were not included. The production routes are either based on ultrasonication or chemical reduction. The results show that the ultrasonication route has lower energy and water use, but higher human and ecotoxicity impacts, compared to the chemical reduction route. However, a sensitivity analysis showed that solvent recovery in the ultrasonication process gives lower impacts for all included impact categories. The sensitivity analysis also showed that solvent recovery is important to lower the blue water footprint of the chemical reduction route as well. The results demonstrate the possibility to conduct a life cycle assessment study based mainly on information from patents and scientific articles, enabling prospective life cycle assessment studies of products at early stages of technological development.

Facing complexity through informed simplifications: a research agenda for aquatic exposure assessment of nanoparticles.

Exposure assessment of engineered nanoparticles (ENPs) is a challenging task mainly due to the novel properties of these new materials and the complexity caused by a wide range of particle characteristics, ENP-containing products and possible environmental interactions. We here present a research agenda in which we propose to face the complexity associated with ENP exposure assessment through informed and systematic simplifications. Exposure modelling is presented as a method for addressing complexity by identifying processes dominant for the fate of ENPs in the environment and enabling an iterative learning process by studying different emission and fate scenarios. Furthermore, the use of models is important to highlight most pressing research needs. For this reason, we also strongly encourage improved communication and collaboration between modellers and experimental scientists. Feedback between modellers and experimental scientists is crucial in order to understand the big picture of ENP exposure assessment and to establish common research strategies. Through joint research efforts and projects, the field of ENP exposure assessment can greatly improve and significantly contribute to a comprehensive and systematic risk assessment of ENPs.