Abstract:
Microplastics (MPs) have been studied across coastal waters as they impact on ecological
integrity of those sensitive ecosystems. Under this context, spatiotemporal variability of
MPs level is a potential confounding factor to be concerned. The present study describes
short-term spatiotemporal variability of MPs distribution in water and sediments, and
selected fish species in Rekawa lagoon, Sri Lanka. Samples were collected in three
occasions from November 2023 to January 2024 selecting eight locations of the lagoon.
Water samples were collected using a plankton net (30 μm), while sediment samples were
collected using a PVC Corer. Five different edible fish species were collected from the
commercial catch. Density separation was performed using 1.2 g/cm3 NaCl solution
followed by digestion with 30% . Fish samples were digested with 10% KOH at 60
spectroscopy. The highest MPs concentrations of sediment (80.00±26.45 items/kg) and
water (0.50±0.19 items/L) were recorded in December, whereas the lowest values were
found in January for sediment (56.66±15.27 items/kg) and water (0.24±0.17 items/L). The
MPs concentration in fish species ranged from 1-4 items/individual in guts and gills. The
heavy rain and excessive riverine influx might have carried plastic debris to the lagoon in
December. Fiber was the most prevalent plastic type collected from water, sediment, and
fish species and most of them were <1mm in size. Polyethylene, polypropylene and
polyester were the major polymer types and most of them were partially degraded. Further,
it emphasizes the need for further research towards the accumulation of MPs in coastal
ecosystems and their toxicity on human.
