The Identification of Microplastics in Karang Mumus and Karang Asam Kecil River Estuary, Samarinda

Abstract

The downstream of Mahakam River that crosses Samarinda City is surrounded by densely populated urban areas and many activities. This area also has several small rivers or tributaries, such as the Karang Mumus and Karang Asam Kecil River. A higher abundance of microplastics is often found in small rivers in urban areas. It is necessary to research microplastic pollution. River water sampling was carried out using an integrated sampling method on both sides and the middle of the estuary. Furthermore, the sample passes through the first filtration process, removal of organic substances using H2O2, separation with a density separator, and second filtration. Microplastic analysis with a microscope was carried out to determine the size, shape, and color. FTIR analysis to determine the type of microplastic polymer. The results showed that the dominant shape of microplastic found is the type of fiber, but fragments and films are also found. The size of the microplastic that dominates is microplastic measuring 25-250µm. While the black color was found more in all samples, but also red, blue, and transparent. Nylon, nitrile, and polyethylene terephthalate (PETE) were the polymers found. The abundance of microplastics is known to decrease with the depth of sampling.