The challenges and the limitations in Life Cycle Impact Assessment for metal oxide nanoparticles, a case study on nano- TiO2

Life Cycle Assessment (LCA) is a chain-oriented tool to evaluate the environment performance of products focussing on the entire life cycle of these products: from the extraction of resources, via manufacturing and use, to the final processing of the disposed products. Through all these stages consumption of resources and pollutant releases to air, water, soil are identified and quantified in Life Cycle Inventory (LCI) analysis. Subsequently to the LCI phase follows the Life Cycle Impact Assessment (LCIA) phase; that has the purpose to convert resource consumptions and pollutant releases in environmental impacts. The LCIA aims to model and to evaluate environmental issues, called impact categories. Several reports emphasises the importance of LCA in the field of ENMs. The ENMs offer enormous potential for the development of new products and application. There are however unanswered questions about the impacts of ENMs on human health and the environment. In the last decade the increasing production, use and consumption of nanoproducts, with a consequent release into the environment, has accentuated the obligation to ensure that potential risks are adequately understood to protect both human health and environment. Due to its holistic and comprehensive assessment, LCA is an essential tool evaluate, understand and manage the environmental and health effects of nanotechnology. The evaluation of health and environmental impacts of nanotechnologies, throughout the whole of their life-cycle by using LCA methodology. This is due to the lack of knowledge in relation to risk assessment. In fact, to date, the knowledge on human and environmental exposure to nanomaterials, such ENPs is limited. This bottleneck is reflected into LCA where characterisation models and consequently characterisation factors for ENPs are missed. The PhD project aims to assess limitations and challenges of the freshwater aquatic ecotoxicity potential evaluation in LCIA phase for ENPs and in particular nanoparticles as n-TiO2.

Impact of metal and metal oxide engineered nanoparticles in soil and plant systems

Nanotechnology promises huge benefits for society and capital invested in this new technology is steadily increasing, therefore there is a growing number of nanotechnology products on the market and inevitably engineered nanomaterials will be released in the atmosphere with potential risks to humans and environment. This study set out to extend the comprehension of the impact of metal (Ag, Co, Ni) and metal oxide (CeO2, Fe3O4, SnO2, TiO2) nanoparticles (NPs) on one of the most important environmental compartments potentially contaminated by NPs, the soil system, through the use of chemical and biological tools. For this purpose experiments were carried out to simulate realistic environmental conditions of wet and dry deposition of NPs, considering ecologically relevant endpoints. In detail, this thesis involved the study of three model systems and the evaluation of related issues: (i) NPs and bare soil, to assess the influence of NPs on the functions of soil microbial communities; (ii) NPs and plants, to evaluate the chronic toxicity and accumulation of NPs in edible tissues; (iii) NPs and invertebrates, to verify the effects of NPs on earthworms and the damaging of their functionality. The study highlighted that NP toxicity is generally influenced by NP core elements and the impact of NPs on organisms is specie-specific; moreover experiments conducted in media closer to real conditions showed a decrease in toxicity with respect to in vitro test or hydroponic tests. However, only a multidisciplinary approach, involving physical, chemical and biological skills, together with the use of advanced techniques, such as X-ray absorption fine structure spectroscopy, could pave the way to draw the right conclusions and accomplish a deeper comprehension of the effects of NPs on soil and soil inhabitants.