Occurrence, characteristics, and polymer associated hazard of microplastics in commercially dried marine seafood from coastal Bangladesh

Microplastic (MP) contamination in seafood has received increasing attention, yet information on commercially dried marine seafood remains limited. This study assessed MP abundance, physical characteristics, polymer composition, spatial variation, and polymer associated hazard in commercially dried marine seafood from Sundarban, Kuakata, Teknaf, and Cox's Bazar, Bangladesh. Six species were examined: Harpadon nehereus, Trichiurus lepturus, Setipinna phasa, Johnius argentatus, Penaeus monodon, and Metapenaeus monoceros . MPs were detected in all samples, with abundance ranging from 0.25 to 1.30 MPs g −1 dry weight. Regional mean abundance ranged from 0.57 ± 0.26 MPs g −1 in Teknaf to 0.91 ± 0.36 MPs g −1 in Sundarban, with no significant difference among the four regions ( p = 0.165). Fibers were the dominant morphology, blue and black particles were frequently observed, and smaller size fractions constituted a substantial proportion of the recovered MPs. FTIR analysis identified seven polymer types, with polyethylene (30.49%) and polypropylene (24.39%) occurring most frequently. The Polymer Hazard Index (PHI) varied markedly among regions, from 86.7 in Sundarban to 2642.7 in Kuakata, reflecting differences in polymer composition and polymer specific hazard scores. Multivariate analyses further revealed interconnected variation in MP abundance, physical characteristics, and polymer composition across the examined samples. Overall, the findings provide a quantitative baseline for MP occurrence and polymer-associated hazard in commercially dried marine seafood from coastal Bangladesh and highlight the need to distinguish environmental contamination from inputs occurring during post-harvest processing and handling.