Regional land-based plastic leakage into the aquatic environment – Waste Flow Diagram applied to the Phu Yen province, Vietnam

Land-based plastic waste is the primary source of ocean plastic pollution, but data regarding its origins and pathways remain limited. This study adapted the Waste Flow Diagram (WFD) tool, initially developed for city-level plastic leakage assessment, for regional application in Phu Yen province, Vietnam. This adaptation aims to capture plastic leakage dynamics across a broader spatial scale to account for all significant sources contributing to ocean plastic pollution. The results show that, excluding Tuy Hoa City, Phu Yen contributes 9.4 kg per capita per year to aquatic environments. Most leakage (88.6 %) originated from uncollected waste in areas lacking collection services. Additional leakage arises from waste collection and transport (7.9 %), disposal sites (2.8 %), and informal activities (0.6 %). Leakage varies widely across districts, ranging from 1 to 55.7 kg/cap/year. The findings offer valuable insights for targeted interventions and policies aimed to enhance waste collection coverage and mitigate regional marine plastic pollution.