Microplastic contamination in thirty commercially important fish species: Distribution, polymer composition, pollution indices, and human health risks.
Level 5 - mechanism / opinion, no new human data
Environmental animal tissue sampling and exposure modeling study without human clinical data (by design analogy, not clinical CEBM)
PubMed 41650713 · doi:10.1016/j.marpolbul.2026.119360
What was done
Researchers evaluated microplastic contamination in 600 specimens across 30 commercially important fish species collected from three landing centres along the Thoothukudi coast between December 2024 and May 2025. Tissues (gastrointestinal tract, gills, and muscle) underwent hydrogen peroxide digestion, and extracted microplastics were characterized using attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy matched against reference libraries (>80% match threshold). Dietary exposure and toxicological risks were calculated via estimated daily intake, pollution risk index, and pollution hazard index.
What was found
Microplastic concentrations varied significantly among species (p < 0.05). Contamination was highest in the gastrointestinal tract (3.67 to 8.75 particles/fish), followed by gills (1.93 to 4.27 particles/fish) and muscle tissue (1.2 to 3.6 particles per 5 g wet weight). Carnivorous species had significantly higher burdens than planktivorous species, with Epinephelus longispinis exhibiting the highest gut contamination (8.75 ± 2.36 particles/fish). Of 1,446 particles analyzed, fibers accounted for 85% of particle morphology, with polyethylene (37.47%) and polypropylene (27.20%) predominating. Estimated daily human intake ranged from 0.047 to 0.159 particles/kg body weight/day, with pollution risk indices (335 to 668) and pollution hazard indices (265 to 302) indicating medium to considerable hazard levels.
Why it matters
The study provides species-specific and tissue-specific contamination baselines for commercial marine fisheries in the Thoothukudi coastal region. Demonstrating microplastic presence in edible muscle tissue confirms direct human dietary exposure pathways from fish consumption.
Limits
The study is restricted to a single geographic coast sampled over a six-month period. Human health risks were derived purely from mathematical models rather than direct toxicological or epidemiological human measurements. Particle detection limits, chemical additive leaching, and nanoplastic fractions below standard FTIR detection thresholds were not reported in the abstract.
Cited by
- supports Microplastics in fish accumulate primarily in the gastrointestinal tract and intestines.