Shape Characterization and Organ-Specific Distribution of Microplastics in Indian Squid (Uroteuthis duvaucelii) from Dumaguete City Public Market

Microplastic contamination in marine food resources has emerged as an increasing environmental and food safety concern; however, data on organ-specific microplastic distribution in commercially sold cephalopods in the Philippines remain limited. This study investigated the occurrence, morphology, and organ-specific distribution of suspected microplastics in Indian squid (Uroteuthis duvaucelii) sold in the Dumaguete City Public Market. Using a quantitative descriptive-analytical design, fifteen squid specimens were collected from three market stalls through convenience sampling. Gill and stomach tissues were dissected, chemically digested using 10% potassium hydroxide (KOH), and examined under stereomicroscopy for microplastic identification and morphological classification. A total of 489 suspected microplastic particles were detected across all sampled squid, indicating contamination in 100% of specimens. Of these, 278 particles were recovered from stomach tissues and 211 from gill tissues. Four microplastic morphologies were identified: fragment, fiber, film, and bead. Fragment-shaped particles were the most abundant, comprising 318 particles (65.03%), followed by fibers with 152 particles (31.08%), films with 16 particles (3.27%), and beads with 3 particles (0.61%). Fisher’s Exact Test revealed a statistically significant association between microplastic morphology and organ location (p = 0.005), indicating that the distribution of microplastic shapes differed between gill and stomach tissues. These findings suggest that Indian squid sold in Dumaguete City may serve as a potential vector of dietary microplastic exposure and provide baseline evidence of microplastic contamination in a commercially important cephalopod species in the Philippines. Continued monitoring using polymer-confirmatory analytical techniques is recommended to strengthen future assessments of seafood contamination and associated food safety implications.