Beatrice Salieri

Freshwater ecotoxicity characterisation factor for metal oxide nanoparticles: A case study on titanium dioxide nanoparticle

The Life Cycle Assessment (LCA) methodology is widely applied in several industrial sectors to evaluate the environmental performance of processes, products and services. Recently, several reports and studies have emphasized the importance of LCA in the field of engineered nanomaterials. However, to date only a few LCA studies on nanotechnology have been carried out, and fewer still have assessed aspects relating to ecotoxicity. This is mainly due to the lack of knowledge in relation on human and environmental exposure and effect of engineered nanoparticles (ENPs). This bottleneck is continued when performing Life Cycle Impact Assessment, where characterization models and consequently characterization factors (CFs) for ENPs are missing. This paper aims to provide the freshwater ecotoxicity CF for titanium dioxide nanoparticles (nano-TiO₂). The USEtox model has been selected as a characterisation model. An adjusted multimedia fate model has been developed which accounts for nano-specific fate process descriptors (i.e. sedimentation, aggregation with suspended particle matter, etc.) to estimate the fate of nano-TiO₂ in freshwater. A literature survey of toxicity tests performed on freshwater organism representative of multiple trophic levels was conducted, including algae, crustaceans and fish in order to collect relevant EC₅₀ values. Then, the toxic effect of nano-TiO₂ was computed on the basis of the HC₅₀ value. Thus, following the principle of USEtox model and accounting for nano-specific descriptors a CF for the toxic impact of freshwater ecotoxicity of 0.28 PAFdaym(3)kg(-1) is proposed.

Human health characterization factors of nano-TiO2 for indoor and outdoor environments

PurposeThe increasing use of engineered nanomaterials (ENMs) in industrial applications and consumer products is leading to an inevitable release of these materials into the environment. This makes it necessary to assess the potential risks that these new materials pose to human health and the environment. Life cycle assessment (LCA) methodology has been recognized as a key tool for assessing the environmental performance of nanoproducts. Until now, the impacts of ENMs could not be included in LCA studies due to a lack of characterization factors (CFs). This paper provides a methodological framework for identifying human health CFs for ENMs.MethodsThe USEtox™ model was used to identify CFs for assessing the potential carcinogenic and non-carcinogenic effects on human health caused by ENM emissions in both indoor (occupational settings) and outdoor environments. Nano-titanium dioxide (nano-TiO2) was selected for defining the CFs in this study, as it is one of the most commonly used ENMs. For the carcinogenic effect assessment, a conservative approach was adopted; indeed, a critical dose estimate for pulmonary inflammation was assumed.Results and discussionWe propose CFs for nano-TiO2 from 5.5E−09 to 1.43E−02 cases/kgemitted for both indoor and outdoor environments and for carcinogenic and non-carcinogenic effects.ConclusionsThese human health CFs for nano-TiO2 are an important step toward the comprehensive application of LCA methodology in the field of nanomaterial technology.

Key physicochemical properties of nanomaterials in view of their toxicity: an exploratory systematic investigation for the example of carbon-based nanomaterial

Currently, a noncomprehensive understanding of the physicochemical properties of carbon-based nanomaterial (CBNs), which may affect toxic effects, is still observable. In this study, an exploratory systematic investigation into the key physicochemical properties of multiwall carbon nanotube (MWCNT), single-wall carbon nanotube (SWCNT), and C60-fullerene on their ecotoxicity has been undertaken. We undertook an extensive survey of the literature pertaining to the ecotoxicity of organism representative of the trophic level of algae, crustaceans, and fish. Based on this, a set of data reporting both the physicochemical properties of carbon-based nanomaterial and the observed toxic effect has been established. The relationship between physicochemical properties and observed toxic effect was investigated based on various statistical approaches. Specifically, analysis of variance by one-way ANOVA was used to assess the effect of categorical properties (use of a dispersant or treatments in the test medium, type of carbon-based nanomaterial, i.e., SWCNT, MWCNT, C60-fullerene, functionalization), while multiple regression analysis was used to assess the effect of quantitative properties (i.e., diameter length of nanotubes, secondary size) on the toxicity values. The here described investigations revealed significant relationships among the physicochemical properties and observed toxic effects. The research was mainly affected by the low availability of data and also by the low variability of the studies collected. Overall, our results demonstrate that the here proposed and applied approach could have a major role in identifying the physicochemical properties of relevance for the toxicity of nanomaterial. However, the future success of the approach would require that the ENMs and the experimental conditions used in the toxicity studies are fully characterized.

How suitable is LCA for nanotechnology assessment? Overview of current methodological pitfalls and potential solutions: 65th LCA Discussion Forum, Swiss Federal Institute of Technology, Zürich, May 24, 2017

The 65th Life Cycle Assessment Discussion Forum was held on May 24, 2017, to discuss the state of research and application with regard to nanotechnology. This conference report presents the highlights of the forum.While all presenters agreed on the relevance of the life cycle assessment (LCA) and risk assessment (RA) methods to offer valuable environmental sustainability assessment ofmanufactured nanomaterials (MNMs), a recurring theme during the forum was the continued lack of environmental data on the manufacturing, release and impacts of such MNMs. Different strategies and research pathways were proposed to tackle this dearth of representative data. The first session provided an overview of the current state-of-the-art in environmental assessment of MNMs from the perspective of regulation, industry and research. The main concern for all these stakeholders is to offer representative environmental assessment and avoid risks in a sector that is rapidly developing. System modellers then proposed, in the second session, different strategies to consider the current lack of knowledge (e.g. uncertainty and potential evolution) in representation ofMNMs production pathways. Prospective modelling, global sensitivity analysis and dynamic probabilistic methods were all shown to be relevant tools to deal with the scarce information. Presenters from the third session subsequently discussed the requirements of evaluating potential impacts (i.e. toxicity) of MNMs if they are released into the environment. Techniques for the characterisation of their effects were introduced, but the consideration of nano-specificities and a clear focus on a limited amount of MNMs were identified as major research challenges that still need attention. The final session then offered a review of how the RA method can be used to complement LCA studies and quantify adverse environmental and human health effects due to exposure at specific sites. All presentations from the 65th discussion forum are available for download (www.lcaforum.ch), and the video recordings can be watched online (http://www.video.ethz.ch/ events/lca/2017/spring/65th.html).