Abstract

This study investigated the presence and characteristics of microplastics in sediments and surface water from three river sites in Surakarta, Indonesia, influenced by distinct sources of pollution: domestic wastewater, industrial effluents, and agricultural runoff. Samples were collected in triplicate at each site and analysed using stereomicroscopy for morphological classification and Attenuated Total Reflectance – Fourier Transform Infrared Spectroscopy for polymer identification. Microplastic abundances ranged from 1.8 to 3.5 particles/L in surface water and 210 to 385 particles/kg in sediments, with the highest concentrations observed at the domestic site. Polyethylene and polypropylene were the dominant polymers, together accounting for over 65% of all identified particles, while fibres and fragments were the most common morphologies. Variations in polymer type and abundance across sites indicate that different pollution sources shape distinct microplastic profiles. These findings provide critical evidence for targeted interventions at both local and national levels and contribute to global understanding of microplastic pollution in urban rivers. The results highlight the urgent need for integrated management strategies and for policy interventions aligned with Sustainable Development Goals 6 (Clean Water and Sanitation) and 14 (Life Below Water).