Abstract:
Microplastic pollution is an escalating concern in coastal and estuarine ecosystems, with
mangrove forests acting as major sinks due to their dense root networks and low hydrodynamic
energy. This study assessed the abundance, distribution, and morphological characteristics of
microplastics in the mangrove areas of the Batticaloa Lagoon, Sri Lanka. Water samples were
collected from five locations, with two replicates from each location, by filtering 50 L of water
through a 100 µm mesh sieve. Organic matter was digested by hydrogen peroxide (H₂O₂), and
the residues were isolated via vacuum filtration using 0.45 µm filter paper and examined under
a stereomicroscope. Where microplastic particles were classified by type, color, and shape.
Microplastic abundance ranged from 700 to 1,020 particles/m³ (mean: 820±52 particles/m³).
The highest abundance was recorded at Location 2 (1,020±20 particles/m³), while the lowest
abundance was observed at Location 5(700±60 particles/m³). Fibers were the dominant
microplastic type, accounting for 80% of the total particles, followed by fragments (19%) and
films (1%). This distribution was consistent with the shape classification, where filamentshaped particles (80%) predominated over irregular-shaped particles (20%). Black particles
were most prevalent (44%), followed by blue (19%), green (15%), red (13%) and other colors
(9%), suggesting textile fibers and degraded fishing gear as likely dominant sources. The
consistently high abundance across all sites, coupled with the predominance of fibrous, darkcolored particles, points to land-based anthropogenic inputs, including domestic wastewater
and fishing activity, as key contributors to contamination in this lagoon system. These findings
establish critical baseline data on microplastic pollution within the Batticaloa Lagoon
mangrove ecosystem, an ecologically vital habitat that supports biodiversity, coastal
protection, and local fisheries. The results highlight the urgent need for sustained monitoring,
source-reduction strategies, and policy interventions to mitigate plastic pollution and preserve
the ecological integrity of this coastal environment.
