Occurrence And Abundance Of Microplastics In Coral Reef Sediment: A Case Study In Sekotong, Lombok-Indonesia

Abstract Microplastics are categorized as less than 5 mm in length-sized plastics. Lombok is located in Indonesia, part of the coral triangle region, and one of the out flow locations of the Indonesian Through Flow (ITF). There is likelihood that microplastics would flow across the ITF and would be accumulated in the coral reef ecosystem, especially in biota and sediment. To improve the knowledge of microplastics pollution in Indonesia, we analyzed sediment samples from 10 stations at coral reef habitats in Sekotong, Lombok-Indonesia. The microplastics concentration in Sekotong varied from 35 to 77 particles per-kg, with average 48.3±13.98 (SD) particles per-kg, found in all ten sampling location. The highest concentration was found in the southwest of Gili Gede Island (77 particles per-kg). All of the microplastics collected were foam (41.20%), fragment (32.51%), granule (22.77%) and fiber (3.52%). Microplastic with size more than 1000 μm found at most, followed by size range of 500-1000 µm, 200-500 µm and particle size less than 200 µm in length. Polystyrene was the most abundant type of plastic polymer identified, followed by polyethylene and polypropylene. This type of polymers indicates that the primary source of microplastics in the Sekotong's coral reef sediment was from the usage of styrofoam, food and beverage packages, also fishing devices. It is strongly suggested that the management of plastic waste to be improved and it is essential to develop an environmentally friendly substance to replace plastics in near future.