Microplastic characterization of sediment in Code River, Yogyakarta City

The purpose of this study was to determine the type, number and size of microplastics in the sediment and to compare each sample deposit in the Code River sediment. This research was conducted in June 2022 in Code River, Yogyakarta. Samples were taken by PVC pipes 10 cm deep, later analyzed in the laboratory. Fourier Transform Infrared (FT-IR) analysis was conducted to determine the plastic types based on the database of the functional groups. Samples in the Code River contained 2,423 particles of microplastic fragments, 721 particles of film, 322 particles of granules and 264 particles of fiber. The total number of microplastics in the Code River sediment from the upstream, middle and downstream zones was 3,730 particles kg-1, of which 550 particles kg-1 in the upstream zone, 1,646 particles kg-1 in the middle zone and 1,534 particles kg-1 in the downstream zone. Microplastics in Code River sediments vary in size from small to large. The smallest size was found in the type of granule at station 2 with a diameter of 51 pm and the largest size was in the type of film at station 3 with a length of 117-1,563 pm. Microplastics in Code River sediments differed in number and size from each zone to another and even within the same sample point.