Microplastics in Sitalakhya River: Distribution and Properties Across Land Uses in Dhaka's Peripheral Waterway

Abstract This study investigates microplastics pollution in the water and bed sediment of a peripheral river of Dhaka city focusing on the possible impact of land use on the abundance and characteristics of microplastics. Water and sediment samples were collected from four locations along the river representing commercial, residential, industrial, and agricultural land uses. The abundance of microplastics ranged from 20 to 412 items/kg in sediment samples and from 3 to 38 items/100 liters in water samples. Some smaller microplastics were found adhering to the surfaces of larger microplastics, which can make it difficult to quantify the microplastics number accurately. The sediment and water samples from commercial areas yielded the highest concentrations of microplastics, suggesting the potential impact of land use and poor waste management practices on microplastics pollution. The majority of microplastics in sediment and water samples were blue and fragmented in shape. FTIR analysis identified the presence of the polymer types in the microplastics. The Sitalakhya River was classified as polluted with microplastics (PLI > 1), falling into risk category I. The higher abundance of MPs in river water and sediment samples from the commercial area highlights the need to develop strategies for the management of MP pollution from urban centers.