Preliminary Study of Abundance and Characteristics of Microplastics on Beach Sediment along the Coast of Rayong Province, Thailand

Abstract This study concentrates on the beach sediment collected at Suchada (SD), Saeng Chan (SC) and Laem Charoen (LM) beaches in the Rayong province of Eastern Thailand. The samples were collected for a preliminary investigation for microplastic contamination. A total of 18 samples were taken parallel with the shoreline at the depth of 5 centimetres. They were collected between the months of August to September 2019. Density separation, microscopic inspection and ATR-FTIR analysis were conducted to analyze the characteristics of microplastics and the type of polymers. The average concentration of microplastics on three beaches was 568.33 ± 153.05 items per kilogram of dry weight. Based on the categorization according to shape, colour, and size, microfibers accounted for a dominant proportion of microplastics. Blue ( > 45%) and 1,000-5,000 µm particle sizes were the most prevalent microplastics in SC and LM beaches, while red (43%) colour and small microplastics (100-500 µm) were the dominant proportion in SD beach. ATR-FTIR analysis determined that the polymers found in microplastic were polypropylene, polyethylene, low-density polyethylene and cellophane.These results indicated that land-based sources also those including tourism activities, fishery activities, river, and sewage discharge from industrial and urban communities are most likely the main source of microplastics in beach sediment along the coast of Rayong province.