Assessment of beach plastic waste pollution using the clean coast index: evidence from Thanh Hoa Province, Viet Nam

Tóm tắt

Marine plastic pollution is an increasingly important environmental and socio-economic challenge for coastal provinces of Viet Nam. Thanh Hoa Province represents a typical coastal setting of the North Central Coast of Viet Nam, where diverse coastal activities, including tourism, industry, capture fisheries and aquaculture, coexist with major river systems such as the Ma, Len and Chu rivers. The presence of these river systems, together with diverse coastal activities and geomorphological settings, contributes to substantial spatial variation in beach litter accumulation. A preliminary assessment using a litter transport model identified three major areas of litter accumulation in Sam Son, Hau Loc and Nghi Son which were subsequently selected for detailed field investigation. This study assesses visible beach litter (>5 mm) across 22 transects in Sam Son, Hau Loc and Nghi Son, Thanh Hoa Province, using material classification and the Clean Coast Index (CCI). Four sampling cells per transect in each of two campaigns yield 176 cell observations (22 × 4 × 2). The national project report dates its winter field campaign to 21 October 2021-13 February 2022 and its later beach campaign to 31 March-23 July 2024; according to the authors, COVID-19 disrupted the planned sampling sequence. The source manuscript reports 15,649 debris items (0.560 items/m²) and 235.69 kg (0.008 kg/m²), of which plastics account for 61.97% of items and 67.51% of mass. Reported area-by-campaign plastic densities range from 0.139 to 1.390 items/m². The project gives also reports an overall CCI of 11.2, with a separate CCI value of 6.9 for plastic litter across the three survey locations; this value cannot be reproduced from the published density summaries and is retained as a source-reported value pending cell-level reconciliation. Hau Loc had the highest reported area-level CCI in both survey campaigns, with values of 27.83 in Season 1 and 15.06 in Season 2. The comparison describes conditions during two seasonal windows in different years and does not isolate a causal monsoon effect.