Unveiling microplastic pollution: Evaluating the role of Sinotaia quadrata (Caenogastropoda, Viviparidae) as a monitoring tool in freshwater ecosystems

Freshwater species play a key role in monitoring microplastics (MPs) pollution, providing insights into its distribution, accumulation, and potential ecological and human health risks in aquatic ecosystems. This study evaluates the invasive snail Sinotaia quadrata as a potential tool for monitoring MPs pollution in freshwater ecosystems heavily impacted by human activities. Specifically, we examined whether the characteristics of MPs (i.e., shape, color, and chemical composition) found in water and sediment were reflected in those accumulated by S. quadrata, and whether MPs accumulation varied across different snail size classes. MPs were detected in all environmental matrices and snail samples, with fragments and filaments as the dominant shapes, blue, white, and black as the most common colors, and polypropylene, polyethylene, and polyethylene terephthalate as the primary polymers. A significant difference in MPs concentration per gram was found across snail size classes, with smaller snails accumulating more MPs than larger individuals, likely due to higher feeding rates during growth. A positive correlation was observed between snail shell length and weight, while MPs concentration per gram showed significant negative correlations with both parameters. These findings suggest that S. quadrata accumulates MPs from the environment, reflecting local contamination levels. While S. quadrata is an invasive species, this study demonstrates its potential utility in MPs monitoring, particularly in the context of eradication efforts. This approach integrates pollution assessment with invasive species management, offering a broader perspective on the role of biological invasions in environmental monitoring.