Phd in ENVIRONMENTAL AND EVOLUTIONARY BIOLOGY

Thesis title: Climate-resilient water safety plans for drinking water supply systems and marine waters, with a particular focus on emerging chemical parameters

Microplastic pollution (MP) has attracted increasing interest in recent years due to the potential impact of these emerging contaminants on the environment and human health. In fact, microplastics are ubiquitous contaminants, present in various environmental matrices, and particularly prevalent in water bodies where they enter from multiple sources. Although the marine environment is particularly susceptible to such pollution - indeed, traces of MPs have been found in remote areas of the planet (e.g. ocean gyres, polar ice caps and off uninhabited islands) - inland waters are also an important pathway. These act as a collection point for MPs from various sources (e.g. degradation of larger plastics, release of synthetic fibres through civil and industrial discharges, or use of materials containing MPs such as toners or cosmetics), from where they can spread further to reach the consumer through introduction into the water supply. Therefore, in response to the growing public concern regarding the effects of these contaminants on human health, the European Commission has set itself the objective of regulating the control of MPs by 2024 by defining: in the light of Directive (EU) 2020/2184, a method for their determination and characterisation, in order to allow their inclusion in a watch list and to reduce their potential exposure via water. The same Directive, transposed in Italy by D.Lgs 18/2023, requires the development and application of a water safety approach, based on a site-specific risk analysis, to guarantee the quality of water resources and to prevent contamination by parameters not currently covered by legislation. Water quality control would make it possible to assess the potential exposure of consumers and the associated potential health risks, and to prevent and/or reduce the risks associated with their consumption. The project therefore aims to achieve two distinct but related objectives: the development and optimisation of a method for the quantitative analysis of microplastics in different aquatic matrices, with particular reference to water intended for human consumption and seawater. Firstly, a method for the identification and quantification of microplastics by Raman microspectroscopy (μ-Raman) was developed and developed for the qualitative and quantitative analysis of microplastics in samples of water intended for human consumption collected at different stages of the water supply chain. In order to optimise a cost-effective and routine analytical method, both strengths and weaknesses were assessed at all stages from sampling to analysis and data processing. The optimised identification and enumeration method allows the identification of microplastics of different shapes and sizes, enabling screening at three different levels of sample characterisation. In addition, repeatability and reproducibility studies of the method were carried out using certified material in order to obtain comparable data and ensure the development of standardised test protocols for all matrices that will be subject to future studies and/or monitoring surveys. Finally, the developed analytical method was applied to the analysis of real samples in a first pilot study. In particular, water samples taken at the entrance and exit of a drinking water plant, from public fountains, domestic taps, water houses and bottled water were analysed with the aim of statistically assessing the presence of microplastics in drinking water and possible human exposure through consumption. Secondly, the research line focused on the development of a method for the determination and characterisation of microplastics in seawater samples collected from different marine regions of the world as part of the Sea Care project. Given the complexity of this matrix, a standardised μ-Raman sampling, pretreatment and analysis protocol was optimised to ensure data comparability. This approach has made it possible to observe how different environmental and anthropogenic factors (e.g. the effect of currents, different anthropogenic pressures, carbon dioxide, nitrogen oxide and sulphur oxide production rates, or shipping traffic) can affect a different distribution of these contaminants, expressed in terms of the number of microplastics identified per volume of seawater sampled.