Microplastic Contamination in the Coastal Environment: A Case Study from the Mae Klong River, Samut Songkhram

Abstract

To investigate the microplastic contamination in the coastal area in Samut Songkhram, we collected sediment samples from six locations in mangrove forests along the Mae Klong River estuary (MK) and the nearby Khlong Khon canal (KK). The microplastics were extracted by ZnCl2 density separation and subsequently H2O2 digestion. The microplastic abundance and physical properties, including their size, color, and shape, were determined under the binocular microscope. The selected microplastic samples were analyzed by µ-FTIR spectroscopy to identify their polymer types. Microplastic concentrations were c. 580 and 1690 items kg-1 d.w. in the samples from MK and KK. The lower microplastic concentration in MK was mainly related to the runoff through the sea. In contrast, the abundant microplastic in KK was possibly caused by the low transportation energy of sediment in the tidal flat. In addition, the microplastics were mainly polyester fiber originating from laundry processes or transport from the vicinity.

Keywords

• Microplastics
• Mangrove sediment
• Surface sediment
• Gulf of Thailand