Microplastic Contamination in Kollidam River Estuary, East Coast of India: A Comparative Study Across Inner, Outer and Mangrove Estuarine Regions

Increased mismanaged plastic has led to widespread microplastic (MPs) contamination in the marine environment. Our study investigates MPs across the inner, outer, and mangrove regions of the Kollidam River estuary on the east coast of India. Surface water and sediment samples at 18 locations were analysed for size, shape, colour, and polymer type. The average MP abundance in surface water and sediment was 2.42 particles. m⁻³and 1580 ± 705 particles. kg⁻¹d.w. respectively. The predominant polymer types observed were PP (40%), PE (26%), and PAc (24%). Medium-sized particles (1–2.5 mm) are more in surface water (44%), and small-sized (0.01–1 mm) particles dominate in sediment samples (50%). The most common MP shapes were fibres and fragments, with transparent MPs being the most frequently observed colour. The results highlight that the mangrove region acts as a potential sink for microplastic pollution.