Abstract:
Macroplastics generated from anthropogenic activities undergo degradation, breaking down into
smaller particles, typically less than 5mm in size, known as microplastics (MPs). Microplastics
are a significant contributor to ecosystem contamination by impacting both terrestrial and marine
environments. Fenneropenaeus indicus (Indian white shrimp), a prominent seafood crustacean
in the Indo-Pacific region, plays a crucial role in marine food webs and global seafood
markets. The MPs in one hundred and fifty shrimp tissue samples were collected between December
2022 and January 2024 from ten coastal sites representing five major coastal regions
of Sri Lanka: the Western, Northwestern, Northern, Eastern, and Southern coasts. MPs in the
samples were initially characterised using a stereomicroscope, with subsequent polymer identification
conducted using micro fourier transform infrared spectroscopy (μ-FTIR). A total of 292
MPs were identified in the gastrointestinal tract and gills. The mean abundance (±SD) of MPs
in Indian white shrimp was 1.86±0.73 items/g, with respect to the weight of the gastrointestinal
tract and gills. Based on the microscopic observation of MP colours, blue MPs were the most
prevalent in both the gastrointestinal tract and gills, accounting for 62.3% and 60.4% of the total
observed colours, respectively. A total of three polymer types were identified through μ -FTIR
analysis, including rayon, polyester and cellulose. Rayon was identified as the predominant
polymer type in the analysed samples. The identified rayon polymer particles commonly used
in the textile manufacturing industry, are presumed to derive from laundry effluents in domestic
wastewater, while other detected polymers likely originate from packaging materials and other
anthropogenic sources. The findings of this study revealed a statistically significantly higher
concentration of MPs in the gastrointestinal tract compared to the gills (Wilcoxon-Signed Rank
test, p < 0.001). The study provides evidence of statistically significant variation of MP contamination
in the Indian white shrimp, Fenneropenaeus indicus , across different sampling sites
(ANOVA, p = 0.001). This issue raises serious concerns, with potentially grave implications
for food safety and the delicate balance of the food web. The cascading effects could disrupt
ecosystems, threaten the integrity of the food supply, and pose serious risks to public health.
