Microplastics contamination in cultured and wild molluscan seafood from the bay of Bengal coast: Ecosystem threats and consumer exposure risks.

Abstract

Microplastic contamination and associated polymer toxicity in mollusks are emerging concerns for ecosystem health and seafood safety in coastal environments. This study compares microplastic abundance, polymer composition, and exposure risks in wild and cultured populations of Crassostrea madrasensis, Perna viridis, and Telescopium telescopium from coastal Bangladesh. Microplastics were detected in all species, with mean abundances ranging from 0.68 ± 0.22 to 1.12 ± 0.10 items g^-1. Fibres dominated, accounting for 77 to 94% of particles, with most measuring less than 500 μm. Transparent and violet particles were most common, indicating sources from textiles, ropes, and aquaculture materials. Polymer composition was determined using Fourier-transform infrared (FTIR) with PE, PET, PS, EVA, Nylon, and PVA identified among the detected polymers. Polymer hazard index values were similar across groups (PHI 15.7-18.7, level II), whereas MPERI was higher in cultured than wild Crassostrea madrasensis (18.6 vs 16.1) but lower in cultured than wild Perna viridis (7.1 vs 17.7). Estimated human intake through mollusk consumption ranged from 0.28 to 0.47 items kg^-1 day^-1, corresponding to 6.2 × 10³ to 1.0 × 10⁴ items per person per year. The dominance of fine fibres and the presence of higher hazard polymers indicate potential chronic ecological stress and food safety concerns. These findings emphasize the need for improved aquaculture practices and targeted monitoring in coastal Bangladesh.