Distribution of Microplastics in Beach Sand on the Can Gio Coast, Ho Chi Minh City, Vietnam

Abstract

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.

Plastic Waste and Difficulties in Management in Vietnam

“…Microplastics were also found in all three sea areas of Tien Giang, Can Gio and Ba Ria -Vung Tau with densities ranging from 0.04 to 0.82 pieces/m3 of seawater, lowest in Can Gio and highest in Tien Giang. The common characteristics of microplastics in these three sea areas are flakes and fibers, concentrated sizes between 0.25-0.5mm and 1-2.8mm, with quite diverse colors [9], [10]. In tidal flat sediments in Hau Loc district, Thanh Hoa province, the content of microplastics in the sediment ranges from 0.002 -0.0798 g/kg with an average value of 0.0229±0.0089 g/kg, corresponding to 2532-6875 pieces of plastic /kg sediment [11].…”

Observing Microplastics in the Environment through Citizen-Science-Inspired Laboratory Investigations

“…As microplastics travel through bodies of water, they sink to the bottom and mix with the subsoil. , As a part of the subsoil, microplastics can be deposited along lakes, rivers, and beaches in the surrounding sediment . Microplastics (e.g., polypropylene, 0.8 g/cm 3 ; polyvinyl chloride, 1.4 g/cm 3 ) can be separated from sand (quartz sand, ∼2.6 g/cm 3 ) using a NaCl-sucrose density solution (1.38 g/cm 3 ), due to density differences. , Separating microplastics from sediment samples entails three steps: (1) aerating the sediment and density solution; (2) allowing lighter particles (microplastics) to float to the surface while heavier particles (sediment) sink; (3) separating the upper portion of liquid containing microplastics from the sand mixture. , This activity was adapted from a previously published activity to be completed in a high school classroom, requiring 30 min to complete, depending on how much the teacher preps the activities. , …”

“…Five to seven drops of NR were placed on the filter, or until the filter was saturated with solution. The saturated filter sat for 5 min to optimize visualizations before being observed under a microscope Figure represents a summarized protocol for Activity Three (Water Samples).…”

“…39,82 As a part of the subsoil, microplastics can be deposited along lakes, rivers, and beaches in the surrounding sediment. 84 Microplastics (e.g., polypropylene, 0.8 g/cm 3 ; polyvinyl chloride, 1.4 g/cm 3 ) can be separated from sand (quartz sand, ∼2.6 g/cm 3 ) using a NaCl-sucrose density solution (1.38 g/cm 3 ), due to density differences. 82,85 Separating microplastics from sediment samples entails three steps: (1) aerating the sediment and density solution;…”

“…The saturated filter sat for 5 min to optimize visualizations before being observed under a microscope. 84 Figure 5 represents a summarized protocol for Activity Three (Water Samples).…”