Occurrence of Microplastics in Kemena River and Niah River of Sarawak, Malaysia

Microplastics in freshwater have been identified as a significant contributor to plastic pollution in marine environments. However, the effect of urbanization on the quantity and spatial dispersion of microplastics in freshwater ecosystems of Sarawak and Malaysia remains unclear. The primary objectives of this study are to investigate the quantity and distribution of microplastics in water and riverbank sediments, as well as to analyze the properties of microplastic particles in the Kemena and Niah rivers. The selection of these rivers was based on the presence of commercial, residential, and industrial areas along their lengths. A total of 24 water and soil sediment samples were collected from three different sites along the Kemena and Niah rivers. The concentration of microplastics in water samples ranged from 60 to 128 items per liter, while sediment samples ranged from 46 to 76 items per liter. The sediment samples also contained microplastics ranging from 21 to 40 and 45 to 125 items per kilogram. Microplastics were observed in various forms, including fibers, films, foam, and fragments, in both water and soil sediment samples. The majority of microplastics were between 0.1 and 1 mm in size, with blue being the most common color observed in river water and transparent in sediment samples. The ATR-FTIR spectrum analysis indicated the presence of four distinct polymers: polyethylene (PE), polystyrene (PS), polycarbonate (PC), and polyethylene terephthalate (PET). This study provides valuable information on the abundance, distribution, chemical composition, and physical properties of microplastics in the Kemena and Niah rivers.