Microplastics abundance in domestic wastewater as a pollutant source for the Daroy River, Indonesia

Domestic wastewater in Gampong Garot, Aceh Besar Regency, Aceh Province, Indonesia is directly discharged to the Daroy River without any treatment process. Domestic wastewater from Gampong Garot has been one of the contributors to microplastics contamination in the Daroy River. The microplastics (MPs) contained in domestic wastewater might come from used soaps and detergent products, as well as the scouring of clothes during washing. Thus, this study aims to investigate the abundance of MPs in domestic wastewater in Gampong Garot. The sampling points were determined based on purposive sampling, with samples taken at the end of the main pipe that directly leads to the Daroy River. Organics in domestic wastewater were removed using 30% H 2O 2 liquid through a digestion process at a temperature of 75°C. MPs characteristics such as size, shape, and colour were visually analysed using a light binocular microscope at 100× magnification, while the polymer type was analysed using Fourier transform infrared (FTIR) analysis. The concentration of MPs in domestic wastewater in Gampong Garot was 30.238 ±1.228 particles∙(100 cm) –3 sample. The most common sizes of MPs were found to be in the range of 1,001–5,000 μm, while the dominant colour and shape were transparent and fibre-like. Polyester (PES) was the most detected type of MPs. These findings highlight the need for wastewater treatment before discharge into aquatic bodies.