CEST2025

Mangrove ecosystems could trap microplastics (MPs) due to their structural complexity. This study assessed microplastic (MP) abundance and characteristics in surface water and sediment from locations (in triplicate) covering the Accelerated Natural Regeneration of Mangroves (ANRM) restoration site in Anawilundawa, Sri Lanka, in 2024. MPs were extracted from surface water (30 L) and sediment (400 mL) samples by organic matter digestion (10% KOH and 30% H₂O₂), density separation (NaCl and NaI), filtration (0.45 μm) and then classified based on shape, colour, and size using a stereomicroscope. Overall, sediment samples exhibited a significantly higher MP abundance (50.5 ± 39.3 items/L) than water samples (0.4 ± 0.2 items/L; ANOVA, df,1,29, p < 0.001). A man-made canal within the southern border had the highest MPs count in sediment (89.2 ± 43.5 items/L), while a recently dug canal in mid-section had the highest MPs in water (0.77 ± 0.58 items/L). Fibres were dominant in both water (87.1%) and sediment (82.8%), with black being the most recorded colour (27.9% in water, 32.7% in sediment). Observed spatial variations suggest the anthropogenic influences on MP accumulation in this sensitive environment, highlighting the need for proper mitigation strategies and continuous monitoring.