Assessing microplastic accumulation in the hepatopancreas of marine and freshwater crabs from the North-East Part of the Bay of Bengal

Abstract

Microplastic pollution significantly impacts both marine and freshwater ecosystems, posing a growing concern for aquatic organisms and food safety. This research focuses on comparing microplastic contamination in the hepatopancreas of three edible crab species: two marine—the giant mud crab ( Scylla serrata ) and the blood-spotted swimming crab ( Portunus sanguinolentus )—and one freshwater species ( Parathelphusa convexa ). These crabs are widely consumed and play an important role in local fisheries and diets. Thirty adult crabs were collected from three sites in the coastal areas of North-East Bay of Bengal and nearby freshwater ponds. Analysis of the hepatopancreas showed average microplastic counts of 0.97 for Scylla serrata , 0.93 for Portunus sanguinolentus , and 3.84 for Parathelphusa convexa . Confocal Raman spectroscopy identified nine different types of microplastics, likely including polyphenylene sulfide (PPS), polyurethane (PUR), polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), polyvinyl chloride (PVC), polystyrene (PS), and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) , which pose risks to aquatic life and human health. These pollutants, which persist in the environment, can disrupt ecosystems and may cause immune system damage and chronic diseases in humans. The Pollution Load Index (PLI) showed that the giant mud crab is most vulnerable to microplastic pollution, with a PLI of 2.31—significantly above the threshold of 1, indicating considerable pollution. This study highlights the urgent need for strategies to mitigate microplastic contamination, considering the health risks linked to consuming contaminated crabs.

Keywords

• Marine crab
• freshwater crab
• microplastic pollution
• Bay of Bengal
• contamination