Abundance of microplastics in Cisadane river - Indonesia

Abstract Microplastics have become a serious threat to the aquatic environment, water treatment facilities, and riverside residents because they are persistent. Microplastics generally come from plastic waste produced by human and industrial activities that enter the rivers. In this study, the Cisadane River was studied for microplastic presence. Sampling was conducted at 11 points along the Cisadane River from the upstream (Muria Jaya) to the downstream (Teluk Naga). Samples were taken using a 200-mesh plankton net and then analyzed using a digital microscope for the microplastic’s presence, sizes, and shapes. Furthermore, material identification was conducted using a Raman Spectroscopy Microscope to determine the material type of microplastic in the samples. According to the result, the Cisadane River contains microplastics of various shapes and sizes. The result shows the abundance of microplastics of 0.8-9.6 particles/m 3 0.8-26.4 particles/m 3 in fibers and fragments, respectively. Microplastics in the form of fragments are the most dominant form. The size of microplastics varies from 65 to 4,932 μm for fibers and 23 to 2,444 μm for fragments. These differences are due to primary and secondary microplastic degradation rates through weathering, abrasion, mechanical disintegration, photolysis, and microbiological activity. The colors of microplastics found were blue, brown, cream, red, black, and transparent, with transparent being the most dominant color. The material types found were polyethylene terephthalate (PET) and polypropylene (PP).