BAU Correspondent
Microplastics have been detected in fish, water and sediments in different parts of Bangladesh, according to studies by Bangladesh Agricultural University (BAU) researchers. The findings highlight growing aquatic pollution, although its specific long-term effects on human health remain inconclusive.
A study by Professor Dr Md Shahjahan of BAU's Department of Fisheries Management detected microplastics in five fish species among 150 specimens collected from Arial Beel: climbing perch (koi), bata, menni (Nandina), gulsha tengra and punti.
Published in the Journal of Hazardous Materials Advances, the study found particles in fish intestines, gills and edible muscle tissues. Climbing perch had the highest concentration.
Water samples contained 11 to nearly 32 particles per litre, while sediment samples had 12 to more than 127 particles per kilogram.
Another study by Professor Dr Md Badiuzzaman Khan of BAU's Institute of Environmental Science and Disaster Management examined fish and bottom sediments from 25 commercial ponds in Trishal upazila.
Microplastics were detected in 90 of 150 fish belonging to six species—rui, katla, pangas, mrigal, common carp and sarpunti. Rui and pangas showed comparatively higher contamination, while sarpunti had the highest average number of particles in its digestive tract. Pond-bottom sediment contained an average of 11 particles per kilogram.
Published in Environmental Pollution, the research was titled “Microplastic in Freshwater Aquaculture: Evidence of Sediment-Fish Transfer and Associated Ecological Risks in Bangladesh”.
Professor Dr Badiuzzaman Khan identified discarded plastic bags and packaging, nylon and polyester fishing nets, abandoned bottles and deteriorating plastic pipes as major sources of microplastic pollution. He said particles released from these materials enter water and eventually fish bodies.
A separate study by Professor Dr Md Shahjahan of BAU's Faculty of Fisheries examined fresh and dried loittya, churi and faissya collected from Fishery Ghat in Chattogram and the Mohipur Fish Landing Centre in Kuakata.
The study found higher concentrations in the gills and digestive tracts than in muscle tissues. Fresh loittya contained an average of 0.21 particles per gram, compared with 41 in dried loittya. The figures for fresh and dried churi were 0.2 and 46 respectively, while dried faissya contained two particles per gram.
Researchers suggested that the higher concentrations in dried fish could be due to plastic pollution in water and moisture loss during drying, which increases particle concentration relative to fish weight.
The researchers, however, said there is no conclusive evidence on the specific health risks microplastics pose to humans.
Professor Dr Md Shahjahan said microplastics were now present in various environmental components and aquatic organisms, including river fish.
He said their effects might emerge over the long term, possibly after 25 to 30 years or in future generations, although no major immediate harm was visibly apparent.
He expressed greater concern about nanoplastics, which are small enough to enter and be absorbed by the human body. He suggested that they could pose health risks and might be linked to serious diseases, including cancer. #EK
