Spatial Distribution and Quantification of Microplastic Contamination in Sediments of Kaliratu Coastal Waters, Kebumen, Indonesia

Kebumen Regency's areas are dominated by shrimp ponds and other anthropogenic activities along the coast. Waste material usually generated from these coastal activities. Plastic waste that disposed of into the environment eventually end up in water areas. The marine debris degrades into microplastics. Degraded microplastics can be found in coastal sediments. This study aims to determine the concentration and distribution of microplastics in sediment at the coastal areas of Kaliratu Beach. In situ sampling were conducted on seven site locations regarding the proporsional location due the waste resources. The 2D hydrodynamics modeling approach with Mike 21 software was applied to model the spatial distribution of microplastics movement concerning east moonsoon seasons. The result showed that the concentration of microplastics on Kaliratu Beach ranged from 25 to 57.5 particles/kg. The contamination of microplastics found includes types such as fibers, fragments, films, and pellets, with various colors and sizes. The polymers constituting these microplastics are polyamide and polyester. Microplastics enter coastal areas through several means, such as river runoff, wind, and being carried by tidal currents, which provide exploratory result comparing to the other location. The distribution of microplastics was modeled using hydrodynamic modeling and particle tracking.