Udupi: A new study by researchers from the Manipal Institute of Technology (MIT), MAHE, and Cochin University of Science and Technology (CUSAT) has revealed the widespread presence of microplastics, that are tiny plastic particles smaller than 5mm and invisible to the naked eye, in two of the most consumed freshwater fish species in coastal Karnataka, raising concerns about plastic pollution and its implications for food safety.The study conducted by Kuruveetil Manikandan Ashitha, Anjali Tamrakar, Gopika Melethil and Anish Kumar Warrier found microplastics in all the fish samples examined, including rohu (Labeo rohita) and pangas/basa (Pangasius pangasius). The findings have been published in the ‘Journal of Toxicology’ (an international peer-reviewed journal published by Wiley Publications).The researchers analysed five organs, gut, gills, liver, gonads and muscle tissue, and detected a total of 1,510 microplastic particles. Rohu showed a higher contamination level, with an average of 58 microplastic particles per fish, compared to 42 particles in pangas/basa. More than 95% of the particles were fibres, predominantly blue and black in colour.According to Anish Kumar Warrier, freshwater bodies such as rivers, lakes, and reservoirs not only support aquatic biodiversity, but also act as major pathways carrying plastic waste from land to the oceans. “Microplastics originate from a variety of sources, including discarded plastic waste, synthetic textile fibres, tyre wear, wastewater discharge, agricultural runoff and atmospheric deposition,” he said. Besides, studies have also shown that scientists estimate that 1.2 million to 2.4 million tonnes of plastic enter the oceans annually through freshwater systems.“The study found that rohu accumulated the highest number of microplastics in its gills and digestive tract, while basa showed a more uniform distribution across organs. Of particular concern was the presence of microplastics in muscle tissue, the edible part of the fish, and in the gonads, the reproductive organs. While the detection of microplastics in gonads does not confirm biological damage, it indicates a potential reproductive risk that warrants further investigation. The presence of particles in internal organs such as the liver suggests that microplastics can move through the fish’s body and accumulate over time,” said Warrier.The researchers warned that microplastics can impair feeding, immunity and reproduction in aquatic organisms. They can also carry harmful contaminants such as heavy metals and toxic organic pollutants through the food chain.The study identified polyester and polypropylene as the dominant plastic polymers in the fish samples, indicating links to types, linking contamination to textile fibres, fishing gear, aquaculture infrastructure and poor waste management practices.The researchers called for improved waste management, greater public awareness, and further research to better understand the long-term ecological and human health impacts of microplastic pollution. “This study highlights the urgent need to reduce plastic leakage into freshwater systems and strengthen efforts to protect aquatic ecosystems, food security, and public health,” the researchers added.
