Assessment of microplastic content in sand sediment and two marine species at Can Gio Mangrove forest and Can Gio coastal area

Abstract

The negative impacts of microplastics on the environment, in recent years, have been noticed in the world and in Vietnam. This study shows the physical characteristics, chemical composition, and abundance of microplastics over time and according to environmental characteristics in Can Gio, Ho Chi Minh City, Vietnam. In addition, this study also assessed the accumulated microplastic content in two endemic species in Can Gio, namely clam (Meretrix lyrata) and mudskipper (Periophthalmodon schlosseri). Four sampling sites along the coast with different ecological characteristics and human activities were selected. Sediment samples were collected into 3 transects and were collected in 2 batches (late dry season and early rainy season) to evaluate the spatial and temporal distribution of microplastics. Density separation method using 1.5g/cm3 zinc chloride (ZnCl2) solution was applied during microplastic extraction examined by attenuated total reflection-Fourier transform infrared spectroscopy (FTIR-ATR). Microplastics were found in all locations with a total amount of 510 ± 320 particles/kg d.w. Microplastic sizes range from 0.01 to 5 mm. Microfibres accounted for the highest percentage (83.85%). The colors of microplastics were also very rich including black, white, blue and red. Polypropylene and polyethylene were the two most common polymers. Due to their properties, microplastics could come from a variety of sources, including resin pellets, tourism, and aquaculture