TYPE AND DISTRIBUTION OF MICROPLASTIC CONTAMINATION IN BEACH SEDIMENT ALONG THE COAST OF THE LOWER GULF OF THAILAND

Abstract

The investigation of microplastic occurrence in 5 beaches along the lower Gulf Coast of Thailand including 1) Ban Bang Dee (BD), 2) Laem Son On (SO), 3) Laem Samila (SM), 4) Talo Kapo (TK) and 5) Thaksin Ratchaniwet Palace (TS) was conducted. The results showed TK with the most microplastics found at 1144 ± 346 pcs/m² followed by SO = 650 ± 500 pcs/m², SM = 484 ± 304 pcs/m², TS = 482 ± 509 pcs/m² and BD = 404 ± 88 pcs/m² which can be related to the different intensity levels of nearby human activities. In the rainy season, microplastics contamination was the most at TS = 974 ± 14.85 pcs/m² followed by TK = 377 ± 167 pcs/m², SO = 263 ± 18 pcs/m², BD =148 ± 209 pcs/m² and SM = 62 ± 79 pcs/m². The higher microplastic amount was observed in the dry season than that in the rainy season since there was not enough rainfall to dilute microplastic abundance. Surprisingly TS located near boundary line has no human activity but the highest amount of microplastic was found here during the rainy season. This is probably caused by counter-clockwise current in the Lower Gulf and the first evidence indicating the existence of transboundary contamination.