Citizen Science for Assessment of Microplastics on Beaches: A Case Study in Mexico

Microplastic pollution is a global environmental problem that affects marine and coastal ecosystems, and whose traditional monitoring is often expensive and limited in coverage. In this citizen science project, through the active participation of 26 local volunteers, data were gathered on the abundance and types of microplastics present on various Mexican beaches, while also promoting public awareness. Participants received materials and basic training to identify and collect microplastics using a standardized methodology, which enabled the creation of a broad and representative database consisting of 63 samples from 42 different beaches. A total of 1500 particles were collected, of which 75.13% were microplastics. The average success rate in collecting microplastics among the volunteers was 63.7 ± 34.7%. The results revealed a considerable diversity of microplastics in the studied areas, with a mean concentration of 3.5 MP/m ± 3.4 MP/m, fragments as the most common type identified (45% of the total), white as the predominant color (43%) and polyethylene as the polymer with the highest proportion (31%). This citizen science approach proved to be an effective tool for environmental monitoring, as the median value of correct identification of microplastics in this study was 80%. This method facilitates large-scale data collection and contributes to community engagement in marine conservation. Moreover, although it needs improvement, the advantages of this methodology are evident in its ability to complement traditional scientific studies and support more informed and participatory public policies in plastic waste management.