A Complementary Assessment of Plastic Pollution Across Shoreline and Bottom Compartments of Bung Xang Lake, a Multifunctional Urban Lake in Can Tho, Vietnam

Multifunctional urban lakes provide ecosystem services but may accumulate plastic waste from surrounding activities. This study assessed plastic pollution along the shoreline and within a sampled bottom-deposition area of Bung Xang Lake, Can Tho City, Vietnam. Plastic represented 99.19% of shoreline litter abundance and 95.63% of dry mass. Exploratory omnibus tests yielded p-values of 0.023 and 0.031 for Abundance density and Mass density, respectively, but no Bonferroni-adjusted pairwise comparison was significant, and unverified transect independence limits between-site inference. All 12 shoreline transects were classified as Extremely Dirty by the Clean Coast Index and as Very High Abundance by the Plastic Abundance Index (PAI = 22.66–92.75). Plastic represented 97.68% of item abundance and 86.49% of dry mass among 560 bottom-litter items. Packaging Plastics dominated the bottom plastic assemblage; 91.77% of plastic items measured 100–500 mm, and all four bottom transects showed Very High Abundance under the operationally adapted PAI (19.71–31.62). The findings provide complementary evidence of plastic accumulation in two physical compartments of the same urban lake without establishing direct transport between them. The observed litter composition may inform management planning for the sampled areas, but specific sources, input fluxes, and intervention effectiveness require further investigation.