Abstract:
Marine litter pollution has become an increasing
environmental concern worldwide. The coastal regions
near major river mouths are highly vulnerable to
accumulation of litter. Crow Island Beach is located at
the mouth of the Kelani River, Sri Lanka, one of the
major rivers in Sri Lanka, which is the source of water
for the capital, however, has no comprehensive
scientific data on source identification, litter
abundance, composition, and pollution status. This
study was conducted in January, February, and May
2026 across 10 sampling locations along the beach to
assess the pollution level at the beach. 2.5 m2 quadrat
was used to collect macro-litter samples, and FTIR
spectroscopy was used to perform polymer
identification. To evaluate the overall pollution status
of the beach, the Clean Coast Index (CCI) and
Pollution Load Index (PLI) were calculated. Results
indicated that domestic and household waste was the
dominant source of macro-litter, and the most abundant
identified polymer types were HDPE and PP. The 0.5-
5 cm range plastic debris category represented the
largest proportion of collected litter, suggesting
extensive fragmentation of macro-litter due to
prolonged weathering. Spatial analysis was used to
identify persistent litter accumulation hotspots,
particularly near major accumulation areas influenced
by riverine inflows. The calculated CCI value of 180.8
and PLI value of 2.2 indicated a highly polluted coastal
environment. Field observations identified clinically
related waste, including syringes and blood collection
tubes. Increased litter accumulation during periods of
rainfall and high-water levels suggest that riverine
transport may contribute to litter accumulation. This
study contributes quantitative baseline data on macro-
litter abundance, polymer composition, and pollution
indices for the coastal region of Colombo.
