Classification of microplastic characteristics in surface water and sediments in the lower Mekong river (Vietnam) in the dry season

Abstract

The study analyzes the distribution and composition of microplastics at 17 locations along the Mekong River (Vietnam) during the dry season (April 2024). Microplastic samples were collected from both surface water and riverbed sediments. Optical microscopy was used to observe and identify the shape characteristics of microplastics, while Fourier Transform Infrared (FTIR) spectroscopy was applied to analyze the polymeric composition. Preliminary results indicate that the distribution of microplastics at monitoring stations depends on various factors, including geographical location, degree of urbanization, transportation activities, population density, riverside exploitation activities, and the hydrological characteristics of the river. Higher densities of microplastics were found in areas near urban centers and residential activities, as well as in riverside exploitation zones. The most common microplastic shapes identified were fibers and fragments. FTIR analysis revealed that Polystyrene (PS), Polypropylene (PP), Polytetrafluoroethylene (PTFE), and Nylon are the primary types of polymers. Comparisons between surface water and sediment samples showed that microplastic accumulation was higher and more diverse in water, with fragments consistently accounting for a larger proportion in most samples. The study provides an overview of the microplastic pollution status in the Mekong Delta river system, serving as a foundation for further research on the environmental impacts on riverside communities.