Distribution of Microplastics in Coastal Waters and Their Implications for the Marine Food Chain

Abstract

Microplastic pollution has emerged as a critical environmental concern, particularly in coastal regions where land-based human activities intersect directly with marine ecosystems. This study investigates the distribution of microplastics in three distinct coastal zones in Indonesia urban, industrial, and conservation areas and examines their potential implications for the marine food chain. Using a quantitative field-based approach, surface water, sediment, and marine organisms (fish and bivalves) were sampled and analyzed through visual identification and Fourier Transform Infrared Spectroscopy (FTIR) to determine microplastic abundance, morphology, and polymer type. The results show significantly higher microplastic concentrations in urban areas compared to industrial and conservation zones, with fibers and fragments being the most dominant forms. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) were the primary polymers identified. Microplastics were detected in 78% of marine organisms collected from urban sites, suggesting active trophic transfer and potential human exposure through seafood consumption. The study confirms a strong correlation between population density, waste management inefficiency, and the level of microplastic contamination. These findings provide important baseline data for future environmental monitoring and call for urgent multi-sectoral efforts to reduce plastic leakage into marine environments and safeguard both ecological and human health.