The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

Microplastics have been identified in all marine environments, from polar regions to tropical waters, and at varying depths, including surface waters and deep trenches. Coastal ecosystems, due to their proximity to land-based sources, influenced by high level of human activities, ocean currents and tides, are recognized as hotspots for microplastic accumulation. However, significant temporal and spatial variabilities complicates our understanding of their distribution. Hong Kong, a densely populated megalopolis with over 7 million inhabitants, is strategically located at the estuary of the Pearl River to test the driving mechanism related to microplastic abundance since it’s under a clear seasonal pattern in river, wind and oceanic currents. In addition, Hong Kong coastal ecosystems are diverse and include sandy shores, mudflats, mangroves, and bedrock. This unique setting provides an exceptional opportunity to investigate the spatial and temporal patterns of microplastics. Here, we will summarize six years of research focused on microplastics in Hong Kong's coastal environment. Our findings reveal notable variability in the abundance and types of microplastics, correlated with source identification, transport pathways, and degradation mechanisms. This work contributes to a deeper understanding of microplastic dynamics in coastal ecosystems and underscores the urgent need for targeted management strategies.

Plastic pollution, polystyrene, beaches, mudflat, mitigation