Assessment of Beach Plastic Waste Pollution Using the Clean Coast Index: Evidence from Thanh Hoa Province, Viet Nam

Marine plastic pollution is an increasingly important environmental and socio-economic challenge for coastal provinces of Viet Nam, where tourism, fisheries, river discharge and coastal urbanization interact to shape the accumulation of beach litter. This study assesses the status, composition and seasonal variation of beach plastic waste in Thanh Hoa Province using a field-survey approach adapted from UNEP and NOAA guidance and the Clean Coast Index (CCI). Two survey campaigns were conducted during the Southwest and Northeast monsoon seasons along 22 transects in Sam Son, Hau Loc and Nghi Son. The broader debris inventory recorded 22,014 items larger than 5 mm, with an average density of 0.788 items/m² and a total weight of 394.8 kg. Plastic items were the dominant material group, accounting for 37.14% of item abundance and 40.04% of total weight. The average CCI for surveyed beaches was 57.3, indicating an extremely dirty condition. Seasonal and spatial contrasts were clear: Nghi Son recorded the largest seasonal decline in debris abundance, while Hau Loc showed persistent accumulation associated with river mouths, fishing villages and boat-anchorage areas. The most frequent plastic categories were food containers, plastic bags and films, hard plastic fragments, cutlery and fishing-related items. The findings show that beach plastic pollution in Thanh Hoa is driven by both land-based consumption and coastal economic activities, and that CCI can provide a transparent, repeatable indicator for local monitoring, targeted clean-up planning and policy implementation