From Trash2Treasure: Turning Citizen Science into an Innovative Protocol for Mapping and Monitoring Beach Litter in Mediterranean Hotspots

Marine litter represents a persistent and transboundary pressure on coastal ecosystems, requiring monitoring approaches that are both scientifically robust and socially inclusive. This contribution presents From Trash2Treasure, an innovative citizen science protocol designed to support participatory mapping and monitoring of beach litter while simultaneously fostering environmental awareness and scientific literacy. The campaign is implemented worldwide through coordinated field activities involving students and local participants.
The paper analyses and compares three Mediterranean case studies identified as litter accumulation hotspots: Kavouri Beach (Greece), Amendolara (southern Italy), and Villapiana Scalo (southern Italy). Using a standardized and replicable protocol, participants conducted systematic beach surveys combining litter collection, categorisation, spatial mapping, and qualitative observations on potential sources and drivers of debris accumulation. Data were collected following harmonised procedures to ensure comparability across sites, while maintaining accessibility for non-expert participants.
Results demonstrate that citizen science can generate coherent and spatially explicit datasets capable of capturing site-specific litter patterns, dominant material types, and recurrent accumulation zones. Cross-case comparison highlights both shared trends, such as the prevalence of plastic items, and local specificities linked to coastal morphology, human activities, and hydrodynamic conditions. Beyond data production, the protocol proved effective in engaging participants in critical reflection on marine pollution, strengthening the science–society interface.
Overall, the From Trash2Treasure experience supports citizen science as a valuable and scalable tool for beach litter monitoring, complementing conventional scientific surveys. The approach supports long-term monitoring strategies, contributes to evidence-based coastal management, and promotes active public participation in addressing marine environmental challenges and localization of SDG 14.