A Meta-analysis of Microplastic Pollution in Poyang Lake: Particle Size Dynamics, Polymer-Specific Risks and Ecological Threats to the Endangered Yangtze Finless Porpoise

This study conducts a systematic meta-analysis of 42 peer-reviewed studies (2016–2022), integrating datasets under ISO 21960:2020 protocols, to assess microplastic (MP) pollution in Poyang Lake and its ecological risks to the endangered Yangtze finless porpoise (YFP). Results show that small particles (< 1 mm) dominate surface waters (72%), while sediments display bimodal peaks at both fine (< 300 µm) and larger (1–2 mm) sizes. Polypropylene (PP, 37.6%) and polyethylene (PE, 30.8%) are the most common polymers, primarily sourced from fishing, agriculture, and industry. Seasonal floods redistribute MPs into porpoise habitats, where hydrodynamic modeling indicates fine MPs (< 0.3 mm) remain suspended longer, increasing their bioavailability and trophic transfer risk. High-risk porpoise zones overlap with PP/PE hotspots and flood-driven deposition areas. By combining polymer-source fingerprints, ISO-standard harmonization, hydrodynamic transport modeling, and trophic transfer pathways, this meta-analysis advances freshwater MP risk assessment and provides targeted management strategies for porpoise conservation.