MICROPLASTIC CONTAMINATION IN URBAN COASTAL WATER OF JOHOR STRAIT: EVIDENCE FROM PENDAS, JOHOR BAHRU

Abstract

This study assessed microplastic contamination in surface water and sediments from Pendas, Johor Bahru, along the Johor Strait, between March and August 2025. Microplastics were extracted using hydrogen peroxide digestion and density separation, then identified under a stereomicroscope, with selected particles confirmed by Raman spectroscopy. A total of 101 particles were recorded, comprising 86 in water and 15 in sediment, indicating that the Johor Strait functions as a receptor of anthropogenic plastic waste. Fibres dominated (71%), followed by fragments (29%), with no films, beads or foams detected. Raman analysis confirmed polyethylene (PE) and polypropylene (PP) as major polymers, reflecting sources from fishing gear, nets and consumer packaging. Blue (47%) and black (30%) particles were most common, suggesting inputs from textiles, fishing activities and port operations, while transparent, red and brown particles were linked to single-use plastics and aquaculture materials. Temporal variation showed the highest abundance in April (49 particles) and the lowest in May (7 particles), likely influenced by rainfall-driven runoff and hydrodynamic changes. August recorded higher counts (37 particles), coinciding with active fishing during the southwest monsoon. Water samples consistently contained more microplastics than sediments, indicating buoyant particles’ persistence in dynamic coastal systems. The presence of larger particles in sediments suggests potential long-term accumulation and ecological risk. This study provides baseline data on urban coastal microplastic pollution, highlighting anthropogenic sources and the need for continued monitoring, mitigation strategies and investigation into interactions between microplastics, heavy metals and biota in Johor’s coastal environments.