Comprehensive Assessment of Pollution Dynamics in Lake Como: Zooplankton, Microplastics, and Sustainable Water Management Strategies.

Abstract

Lake Como in Northern Italy is a vital freshwater ecosystem that supports a range of socioeconomic activities, including tourism, agriculture, and energy generation. This multifunctional role, however, has led to increased pollution pressures, particularly through the influx of microplastics and other aquatic debris, exacerbated by high tourism volume impacts. Despite growing concerns over microplastic contamination in freshwater systems, most existing research focuses on marine environments, leaving a critical knowledge gap regarding lakes. This thesis aims to address this gap by investigating the sources, distribution, and ecological impacts of plastic debris (and its derivatives e.g. microplastics) pollution in Lake Como, with a particular emphasis on effects on zooplankton, an essential component of the lake's food web and a key bioindicator of water quality. This research pursues four main objectives: (1) to analyze the concentration, composition, and spatial distribution of microplastics in Lake Como through systematic sampling and laboratory analysis; (2) to assess how climate change is affecting the functioning of wastewater treatment plants (WWTPs) in the region and their ability to manage microplastic loads; (3) to explore the effects of algal bloom-induced turbidity on debris detection and ecological assessment, using advanced remote operating vehicle (ROV) technology for monitoring; and (4) to investigate the application of circular economy principles in waste management, with a specific focus on recycling textile waste as a strategy to curb pollution in freshwater systems. Fieldwork conducted over multiple seasons involved sampling eight sites across Lake Como, coupled with ROV monitoring to document both floating and submerged debris. Preliminary results reveal a heterogeneous distribution of plastics, with higher concentrations near populated and tourist areas, indicating localized pollution sources. Analysis shows that the types of microplastics range from fragments to fibres, implicating both municipal waste and industrial discharge as contributors. Furthermore, climate-related stressors, such as extreme weather events and increased runoff, have been shown to impair WWTP efficiency, complicating efforts to control microplastic contamination. The findings highlight an urgent need for 4 innovative waste management strategies. Circular economy practices, particularly textile waste recycling, are proposed as viable solutions to reduce microplastic inputs and enhance sustainable waste utilization. This study not only contributes to the limited but growing literature on freshwater microplastic pollution but also offers practical recommendations for pollution mitigation and ecosystem health preservation in Lake Como and similar freshwater bodies. These recommendations include policy interventions and infrastructure improvements that can help manage anthropogenic pressures on freshwater ecosystems in a changing climate.Lake Como in Northern Italy is a vital freshwater ecosystem that supports a range of socioeconomic activities, including tourism, agriculture, and energy generation. This multifunctional role, however, has led to increased pollution pressures, particularly through the influx of microplastics and other aquatic debris, exacerbated by high tourism volume impacts. Despite growing concerns over microplastic contamination in freshwater systems, most existing research focuses on marine environments, leaving a critical knowledge gap regarding lakes. This thesis aims to address this gap by investigating the sources, distribution, and ecological impacts of plastic debris (and its derivatives e.g. microplastics) pollution in Lake Como, with a particular emphasis on effects on zooplankton, an essential component of the lake's food web and a key bioindicator of water quality. This research pursues four main objectives: (1) to analyze the concentration, composition, and spatial distribution of microplastics in Lake Como through systematic sampling and laboratory analysis; (2) to assess how climate change is affecting the functioning of wastewater treatment plants (WWTPs) in the region and their ability to manage microplastic loads; (3) to explore the effects of algal bloom-induced turbidity on debris detection and ecological assessment, using advanced remote operating vehicle (ROV) technology for monitoring; and (4) to investigate the application of circular economy principles in waste management, with a specific focus on recycling textile waste as a strategy to curb pollution in freshwater systems. Fieldwork conducted over multiple seasons involved sampling eight sites across Lake Como, coupled with ROV monitoring to document both floating and submerged debris. Preliminary results reveal a heterogeneous distribution of plastics, with higher concentrations near populated and tourist areas, indicating localized pollution sources. Analysis shows that the types of microplastics range from fragments to fibres, implicating both municipal waste and industrial discharge as contributors. Furthermore, climate-related stressors, such as extreme weather events and increased runoff, have been shown to impair WWTP efficiency, complicating efforts to control microplastic contamination. The findings highlight an urgent need for 4 innovative waste management strategies. Circular economy practices, particularly textile waste recycling, are proposed as viable solutions to reduce microplastic inputs and enhance sustainable waste utilization. This study not only contributes to the limited but growing literature on freshwater microplastic pollution but also offers practical recommendations for pollution mitigation and ecosystem health preservation in Lake Como and similar freshwater bodies. These recommendations include policy interventions and infrastructure improvements that can help manage anthropogenic pressures on freshwater ecosystems in a changing climate