Microplastics in Sediments of the Urban River Jinjiang: Sources, Distribution, and Risk Assessment

The distribution and composition of microplastics (MPs) in sediments provide a useful reflection of overall MP pollution for urban river systems. Sediment samples were collected from the Jinjiang River, the main tributary of the Minjiang River, to articulate the sources, distribution, and risk status of MPs. The results showed that the MPs in Jinjiang sediments were composed of polypropylene (PP), polyethylene (PE), polyethylene glycol terephthalate (PET), polystyrene (PS), and Rayon, with per kilogram of dry sediment (n/kg) ranged from 21 to 924 particles, and PP and PE were accounted for more than. MPs varied in colour, shape and size (100–5000 µm), although those observed were predominantly green, fragmented and about 1,000–5,000 µm. The dominant sources of MPs in sediments could be domestic waste and laundry effluents. The risk assessment for MPs showed that upstream and downstream were at moderate risk, while midstream was at low risk. This study can provide a reference for the management and control of MP pollution in urban rivers.