This study reports the distribution of microplastics (MPs) in surface water and estuarine sediments in South and North Setiu Wetland in the South China Sea. Sampling was conducted bimonthly for one year from November 2016 to November 2017, including the northeast and southwest monsoons. Water surface and sediment samples were collected from six different sampling stations (STs). Samples were sorted based on physical analysis (optical observation) and selected particles were further analyzed by chemical characterizations. The findings of this study indicate that a total of 0.36 items/L and 5.97 items/g particles of MPs were found from characterizations surface water and dry sediment, respectively. Among the selected stations included in this research, ST3 (1.375 ± 0.347 items/L) and ST2 (14.250 ± 4.343 items/g) were individually identified as high potential MP sinking areas, exacerbated during the northeast and southwest monsoons. Transparent, film, and filament MP types were consistently found across all stations. Microplastic filaments revealed a functional group of polypropylenes based on the main peak spectrum at 2893–2955 cm⁻¹ (CH alkyl stretching), 1458 cm⁻¹ (CH₂ bending), and 1381 cm⁻¹ (CH₃ bending). Microplastic materials were thermally decomposed by pyrolysis-gas chromatography–mass spectrometry (Pyr–GC/MS) and identified as cyclohexane and cyclohexene derivatives, as well as precursors of polymer blends. The distribution of MPs in both matrices varied according to different seasons. These findings provide useful baseline information on the distribution of MPs from the estuarine area in Malaysia and South China Sea waters.

这项研究报告了南海Setiu湿地和北部Setiu湿地的地表水和河口沉积物中的微塑料（MPs）分布。从2016年11月到2017年11月，采样每两年进行一次，包括东北季风和西南季风。水面和沉积物样本是从六个不同的采样站（ST）收集的。根据物理分析（光学观察）对样品进行分类，然后通过化学表征对选定的颗粒进行进一步分析。这项研究的结果表明，从地表水和干燥沉积物的特征中分别发现了总计0.36克/升和5.97克/克的MP颗粒。在本研究中选择的站点中，ST3（1.375±0.347项目/ L）和ST2（14.250±4）。东北地区和西南季风加剧了343个项目/ g）的高潜在MP下沉区域。在所有工作站中始终可以找到透明，胶片和灯丝MP类型。超细塑料长丝根据2893–2955 cm的主峰光谱显示了一个聚丙烯官能团^-1（C H烷基拉伸），1458 cm ^-1（C H ₂弯曲）和1381 cm ^-1（CH ₃弯曲）。微塑料通过热解-气相色谱-质谱法（Pyr-GC / MS）进行热分解，被鉴定为环己烷和环己烯衍生物以及聚合物共混物的前体。两种基质中MP的分布随季节的不同而变化。这些发现提供了有关马来西亚和南海海域河口地区MP分布的有用基线信息。