Microplastics have become a global concern due to their persistent properties
and impacts on the marine environment. This research investigates
pollution sources and behaviors of microplastics at UNESCO Can Gio
Mangrove Biosphere Reserve. Density flotation with sodium chloride is
employed to extract microplastics from sand at Can Gio Beach, and a
double-filtration procedure is developed to recover microplastics from seawater
at the beach and Dong Tranh Cape. The microplastics’ morphology
and type are analyzed by micro-Raman spectroscopy. The results show
that microplastics are accumulated at concentrations from 31.99 to 92.56
MPs g−1 at various sand layers. The seawater at Can Gio Beach and Dong
Tranh Cape contains 6.44 and 3.75 MPs L−1 of microplastics, respectively.
White polyethylene fragments predominate, and all the microplastics comprise
small secondary microplastics with a minimum size of 25 μm and a
maximum size of 260 μm for fragments and a length of 640 μm for fibers.
The proportions of polyethylene, polypropylene, polystyrene, and polymethylmethacrylate
are similar. The differing percentages of other compositions
in sand and seawater are attributed to the morphology and density of the
microplastics. The results indicate the extent of microplastic pollution and
suggest appropriate strategies for tourism development at the Biosphere
Reserve.