Microplastic Occurrence in the Water and Sediment of Miri River Estuary, Borneo Island

Currently, plastic pollutants in the aquatic environment have received much attention. The studies on the abundance of microplastics in the river system are consequently lower compared to the studies on the marine system. The study aimed to determine the abundance of microplastics in water and riverbank sediments of Miri River and classify their spatial distribution patterns. In this study, water and sediment samples were collected from five sampling points in Miri River to investigate the abundance and distribution of microplastics as well as the characteristics of microplastics in Miri River. The abundance of microplastics in water samples was within the range of 0.8 to 2.1 mg/L or 10.7 to 14.3 particle /L. In sediment samples, the abundance of microplastics was within the range of 26.2 to 62.5 mg/kg or 283.7 to 456.2 particle/kg. The main type of microplastics detected in both water and sediment samples was fragment type with proportions of 57.3% and 57.9%, respectively. The most abundance particle size of microplastics was size of less than 1 mm. Colored microplastics such as black and blue were mainly found in both water samples and sediment samples. The polymer types were identified using FTIR which were polyethylene, polypropylene, polyurethane, ethylene propylene diene monomer, Butyl-Branham, and ethylene vinyl acetate.