Assessment of Sediment Grain Size and Its Correlation with Microplastic Accumulation and Characteristics in the Kahayan River, Indonesia

The purpose of our research was to investigate the relationship between sediment grain size and the accumulation and characteristics of microplastics in the Kahayan River, Indonesia. The average abundance of microplastic in sediment was 7.3 ± 4.3 n/kg dry weight. The result showed a significant difference between predominant sediment grain size and microplastic occurrence in sediment. Moreover, sediment types of very coarse sand (1–2 mm), coarse sand (0.5–1 mm), and fine sand (0.1–0.2 mm) showed a significant and strong correlation with microplastic abundance. Predominant sediment grain size and microplastic shape (fragment, fiber) or size of >1000 µm also have a significant and strong correlation.