Marine debris pollution in mangrove at Cua Hoi, Thanh Hoa: Status and Source assessment

This study investigates the status and sources of marine debris pollution in mangrove ecosystems of the Cua Hoi estuarine area, Thanh Hoa Province, Vietnam. Marine debris was surveyed at three sites, including two mangrove forests (S1 and S2) and one adjacent beach site (S3), following standardized international monitoring protocols. A total of 1,192 debris items were collected from 27 sampling units. Mangrove site S1 exhibited the highest average marine debris density (8.68 n/m²), while S2 showed a much lower density (0.67 n/m²), and the beach site S3 recorded the lowest value (0.052 n/m²). Plastic debris dominated the material composition, accounting for 92.79% of all items, with LDPE, PE, and PS being the most common polymer types. The dominant size class across all sites was 5–25 mm, though mangrove areas retained a higher proportion of larger debris compared to the beach. Source analysis revealed that public litter was the primary contributor (78.27%), followed by fisheries debris (21.14%), indicating strong land - based and nearshore influences. Overall, the results highlight the role of mangrove forests as natural traps for marine debris and provide scientific evidence to support improved waste management and conservation strategies in estuarine mangrove ecosystems.