Microplastics pollution in Vietnam has received significant attention in recent years because of its adverse effects on the environment. This study examined the abundance, physical characteristics, and chemical composition of microplastics in beach sand from the Can Gio Coast, Ho Chi Minh City, Vietnam for the first time. Five beaches with different features and anthropogenic activities along the Can Gio Coast were selected. Ninety sand samples were collected from the edge of the water to the upper shoreline at different depths to assess the spatial distribution of microplastics. Microplastics were extracted by density separation in a solution of sodium chloride (NaCl) and zinc chloride (ZnCl₂) and examined by attenuated total reflection Fourier transform infrared spectroscopy (FTIR-ATR). The abundance of microplastics varied from 0 to 6.58 pieces/kg d.w. Microplastics were detected mostly along the upper shoreline and in the surface sand layer. The dimension of the microplastics ranged from 2.8 to 5 mm (71.4%), granules accounted for the highest proportion of shape (42.9%), and white and blue were the two most prevalent colors (81%). Polypropylene, polystyrene, and polyethylene were the three most common polymer types. The characteristics of microplastics indicate that their origin may be from resin pellets, tourism activities, and aquacultural activities.

Microplastic pollution has become a worldwide concern. However, studies on the distribution of microplastics (MPs) from inland water to the ocean and their affiliated polycyclic aromatic hydrocarbons (PAHs) are still limited in Vietnam. In this study, we investigated the distribution of MPs and PAHs associated with MPs in canals, Saigon River, and Can Gio Sea. MPs were found at all sites, with the highest average abundance of MPs being 104.17 ± 162.44 pieces/m³ in canals, followed by 2.08 ± 2.22 pieces/m³ in the sea, and 0.60 ± 0.38 pieces/m³ in the river. Fragment, fiber, and granule were three common shapes, and each shape was dominant in one sampling area. White was the most common MP color at all sites. A total of 13 polymers and co-polymers were confirmed, and polyethylene, polypropylene, and ethylene-vinyl acetate were the three dominant polymers. The total concentration of MPs-affiliated PAHs ranged from 232.71 to 6448.66, from 30.94 to 8940.99, and from 432.95 to 3267.88 ng/g in Can Gio sea, canals, and Saigon River, respectively. Petrogenic sources were suggested as a major source of PAHs associated with MPs in Can Gio Sea, whereas those found in Saigon River and canals were from both petrogenic and pyrogenic sources.