Developing a Visual Counting Method to Quantify Riverine Plastic Litter: A Case Study of Rivers in Semarang City, Indonesia

Abstract Indonesia has established a national action plan on marine plastic debris to tackle the issue of debris. Because most in is likely due mismanaged waste, it important address problem riverine river Indonesia. The objectives this study are visually observe condition terms pollution, quantify litter river, and develop visual counting model quantification. (> 2.5 cm) method based European standard was applied main challenge high turbidity water that obstructed observation. deployment fishing net also not appropriate collect Most stranded riverbanks, indicating flow elevated runoff during rainy season. Four types polymers were obtained, i.e., polyethylene terephthalate (PET), low-density (LDPE), polypropylene (PP), polystyrene (PS). highest percentage macroplastics LDPE, which usually used as daily packaging (90%).