Abstract:
The pollution of microplastics is a worldwide environmental issue that is continuously gaining
evidence of creation in the environment and effects on the eco-health implications in aquatic
systems. This paper evaluated the prevalence, properties, and polymer content of microplastics
in Oreochromis niloticus (Tilapia) of the Eravur Lagoon (part of Batticaloa lagoon) in Sri
Lanka. A total of sixty sexually maturing individuals were collected with the assistance of the
local fishermen. Gastrointestinal tracts were removed, placed in 10 M NaOH (5:1 w/v) at 60◦C
for 24 h, and then filtered through 0.25 mm mesh and observed under a stereomicroscope to
categorise them on their shape, size and colour. FTIR analysis was used to confirm the polymer
types. Statistical tests in SPSS entailed descriptive statistics, Pearson correlation, multiple
regression, and one-way ANOVA with Tukey HSD. A total of 86 microplastic particles were
retrieved, with an average of 1.43±1.42 particles per fish. Strong positive correlations were
revealed between fish length (r = 0.736, p < 0.01), weight (r = 0.814, p < 0.01), and microplastic
abundance; both variables were proven to be significant predictors with multiple regression
analysis (R2= 0.682, p < 0.001). There were large proportions of filaments (66.28%) and few
fragments (27.91%) and films (5.81%) (F (2,177) = 8.69, p < 0.001). The sizing category of
<1 mm was significantly dominated by 56.98% of the particles compared to the 2 - 4 mm fraction
(F = 14.62, p < 0.001). The black microplastics (58.14%) were found more significantly
compared with transparent (23.26%), blue (12.79%) and green (5.81%) particles (F = 7.842,
p < 0.001). The FTIR approach identified the presence of polyethylene, polypropylene, and
nylon, which indicates their origin through fishing nets and packaging waste as well as textile
effluents. These results reflect the vulnerability of Eravur Lagoon environment. The findings
have the potential to inform guidelines on waste disposal, fishing equipment and education, and
contribute a baseline dataset on which subsequent seasonal and trophic-level analysis can be
built to inform national policy in plastic pollution reduction.
