Several recent studies report that microplastics are being found in fish from rivers and water bodies across Bangladesh. The particles have been detected not only in the stomach and digestive tract but in the muscle tissue of the fish.

A microplastic is any plastic particle less than five millimetres across. Such particles form when larger plastic breaks down, and from synthetic clothing fibres, tyre wear, cosmetics and industrial waste. They reach rivers, canals, lakes and seas, and enter fish through food and water.

A study by the fisheries management department of Bangladesh Agricultural University found microplastics in five kinds of fish in Arial Beel: koi, bata, meni, gulsha tengra and puti, all known as native species. The highest concentration was found in the omnivorous koi.

Professor Md Shahjahan of the same department, who led the research team, said microplastics were also found in the muscle tissue of the fish. That matters because people generally eat the muscle rather than the gut.

Finding such particles in a fish's intestine or stomach is not unusual. Fish take them in with food and water and they can accumulate in the digestive tract; a fish's food includes water, smaller fish, plankton and even mud.

Asked whether small or large fish carry the greater risk, Professor Shahjahan said: "People usually eat small fish along with the intestines. By that logic small fish should carry the most microplastics. But it is difficult to say with certainty which fish has more."

Researchers have not concluded that the presence of microplastics means an immediate health risk. Work continues worldwide on the long-term effect on the human body, on how much microplastic is harmful and on how the risk arises. For fish farmers and wholesalers the question comes back to controlling pollution in the water body.

Source: BBC Bangla