Comparison Between the Plastic Waste Influx of Rural Rivers: Mlese River in Indonesia and Hamada River in Japan

Abstract

Marine plastic pollution has become a global concern as plastic wastes continue to accumulate in the world’s oceans. Usually, such accumulation occurs due to garbage leakage from land, which eventually flow into the river pathways through surface runoff or wind. This study aims to draw a parallel between the garbage influx of two rural rivers in Indonesia and Japan. Data collections were carried out at one of the river points in Indonesia’s Mlese River and Japan’s Hamada River when the weather was not rainy. The river characteristics and influx of plastic litter into the river streams were analysed at a specific time of a day. In Mlese River, trashboom method and, in Hamada River, manual netting method were used to trap the plastics. The waste outflow was 370 g/hr from Mlese River and 0.25 g/hr from Hamada River. Despite the average discharge of the two rivers being quite similar (0.34 m3/s), the plastic outflow in Mlese River was about 1400 times compared to the plastic outflow of Hamada River, proving the waste leakage problem in Indonesia to be greater. Data must be collected in rainy days as well to better understand the complete situation of waste influx in these rivers.