Levels of Microplastics in Aquatic Ecosystem Components of the Kedung Ombo Reservoir, Central Java: Analysis of Water, Tilapia (Oreochromis mossambicus), Sediment, Macroalgae, and Gastropods

The widespread use of plastics in daily activities poses a significant threat to aquatic environments and human health, primarily because plastics degrade into microplastics that easily accumulate in biota and may cause harm when ingested. The aim of this study was to identify the abundance and types of microplastics in water, gastropods, tilapia fish, macroalgae, and sediments. This study was conducted from September to December 2024 in the Kedung Ombo Reservoir. The abundance, shape, and size of microplastics were analyzed using an Olympus CX23 binocular microscope with a 4×/0.10 objective lens. Polymer type analysis of the microplastics was conducted using Fourier Transform Infrared (FTIR) spectroscopy. The abundance of microplastics found at each observation station, consisting of water, gastropods, tilapia fish, macroalgae, and sediment samples, was 122, 2,088, 2,700, 1,036, and 8,847 particles/kg, respectively. Microplastics were classified based on their size into small (<0.5 mm), medium (0.5-<1 mm), and large (1-5 mm), with percentages of 72%, 13%, and 15%, respectively. The shapes of the detected microplastics included fibers (39%), fragments (19%), films (17%), pellets (15%), and foams (11%). The microplastics detected were black (33%), red (15%), purple (6%), yellow (12%), blue (8%), green (6%), and clear (20%). The microplastics identified were polyethylene terephthalate (PET), polyethylene (PE), and polystyrene (PS). The abundance of microplastics has been detected in various compartments of the Kedung Ombo Reservoir. This needs to be monitored regularly, because microplastic accumulation on organisms can be harmful to health and the environment.