Abstract
Mangroves can become traps for plastic waste, so plastic waste has a long residence time and then fragments into microplastics and settles in mangrove sediments. The health level of mangroves will impact other ecosystems, such as seagrass and coral reefs. This research aims to identify microplastics in the mangrove sediments of Pari Island, Jakarta Bay, based on their shape, colour, size and chemical composition, and compare the microplastics distribution at different sampling times. The samples obtained were mangrove sediments from Pari Island, Jakarta Bay, in September 2021, representing the transition season, and January 2022, representing the western season. The stages of this research include measuring mangrove cover and health levels, microplastic extraction and microplastic identification. Microplastic extraction was done by adding ZnCl2, followed by 30% H2O2 and FeSO4 7H2O. Quality control was performed to minimize contamination in the field and laboratory. Visual identification using a microscope produces microplastics with dominant forms, namely fragments and fibres, with the dominant colours being black, red, transparent and blue and the size being dominated by the <200 μm size group. Ethylene propylene, Polyvinyl chloride (PVC), Polyurethane, and Polyethylene are the four most abundant polymers in this study. The Kruskall-Wallis U test with a result of 0.4386 (> 0.05) shows that the abundance of microplastics in the west and transition seasons is insignificant. Spearman correlation test results show p-value = 0.6036 (<95%) and rho = 0.2182179; microplastic abundance has a significant relationship with the Mangrove Health Index (MHI).