Analysis of Microplastic Content in Surface Water of the Gajah Mungkur Reservoir in Indonesia

Abstract Dispose of plastic waste into surface water causes microplastic (MPs) pollution, which can pollute water areas such as in Gajah Mungkur Reservoir (GMR) Indonesia. This research aims to analyze the abundance, shape, and polymer type of the MPs found in the GMR area. The samples were collected at three locations (intake SPAM Wosusokas, the hydroelectric power plant (outlet), and the inlet (Check DAM Gedong in Keduang River). The water samples were taken 10 times using a 20 L container and then filtered using a 1.68 mm diameter plankton net (No. 14). Afterward, the sample was analysed using microscopical identification and FTIR-ATR analysis. The abundance and shape of the MPs sample were analyzed using microscopic identification. The polymer type of the sample was analyzed using FTIR analysis. Microplastic distribution in GMR areas was also mapped using a QGIS application. The average abundance of the MPs in the sampling location was 340-820 n/m 3 . The MPs shape found in the sample were fibre (39%), fragment (11%), and filament (50%). The highest microplastic abundance was found in Check DAM Gedong of Keduang River (inlet). Polymer types of the microplastic sample were polypropylene (PP) and polystyrene (PS). These findings revealed that the MPs are already present at the surface water in Indonesia and threaten the water quality.