Environmental risk of micro and nanoplastics in wastewater treatment systems and receiving bodies
Microplastics have long been recognized as environmental pollutants causing impacts to marine and terrestrial life. Microplastics decompose and break up into smaller plastic debris under the action of microbiological and physicochemical degradation processes leading to nanomaterials. Nanoplastics, like other nanomaterials, have unique properties due to their size, shape and their capacity to interact with other substances due to their large surface area. Nanoplastics can produce physical damage but they may also be transported across cell membranes and persist in the environment due to their relative inertness. The chemical composition of plastics makes them a conveyor for non-polar anthropogenic pollutants supposing an additional risk factor for which very little is known.
This proposal aims at providing the information required to evaluate the risk posed by nanoplastics to freshwater ecosystems with particular attention to the processes of fragmentation and environmental transformation in real world scenarios. We will also study the role of micro and nanoplastics as vectors for other pollutants and, for the case of larger particles, as habitats for microbial communities growing on them as biofilms. In particular, we will investigate the damage to organisms naturally exposed to nanoplastics in the receiving bodies of wastewater discharge. The toxicity of nanoplastics to photosynthetic microorganisms will be combined with protozoa and invertebrates representing three trophic levels. Special attention will be paid to the mechanisms of nanoplastic internalization and to their toxic action by using a battery of fluorochromes as indicators of cytotoxicity, cell viability, oxidative and genotoxic damages.