Researchers have found toxic microplastics in the flesh of edible fishes in Dhaka’s lakes, which is posing a risk to human health. The information was revealed by a study which was conducted on the flesh of edible fishes in three lakes and published in the journal ‘Environmental Science and Pollution Research’ last December. The study determined the microplastics pollution in water, sediment, and fish samples of three urban lakes.
It was carried out to assess the bioaccumulation of microplastics from the lake environment to fish’s edible (flesh) and inedible tissue (gut), ecological risk and consequent human exposure to microplastics by fish consumption. A total of 43 fishes were collected from Dhanmondi Lake, Saturia Thana Lake and Jahangirnagar Cooperative Housing Society (JCHS) Lake. The highest number of microplastics was found in the flesh of Labeo bata of JCHS Lake and in the gut of Catlacatla of Dhanmondi Lake.
Prof Dr Shafi Mohammad Tareq, fellow at the Higher Education Academy-UK, who was one of the study researchers, told the FE that this study provides evidence of anthropogenic microplastics in the edible tissue of the fish in urban lakes in Bangladesh. “Earlier, we studied microplastics’ presence in fish gut, but this is first of its kind on edible parts of freshwater fish in Bangladesh,” he added. He, also a teacher at the Department of Environmental Sciences, Jahangirnagar University, said, “We conducted the study to know the pollution status of urban lakes. We conducted all three fishes, water and sediment of the same lakes.”
If microplastics is taken, it can make disable the digest system and develop cancer in the human body as microplastics is a proven toxic substance, he added. “We can now confirm that we intake microplastics contaminated foods (edible fish flesh),” the scientist said. The source of the microplastics in urban lakes is nothing but human. Local population often disposes of numerous white/transparent plastic items such as bags, glasses, and bottles after use, the study reveals. It also said the most dominant shape of microplastics was fiber and fragments, 0.1-0.4 mm was the dominant size range, and blue, purple, and transparent were the dominant colors.
Additionally, the abundance of blue-coloured microplastics can be attributed to the prevalent use of blue nylon in fishing nets in Bangladesh. “Urban lakes like Dhanmondi Lake are popular recreational sites in Dhaka. Visitors throw plastic packets, single use plastic, plastic water bottles in the open environment and those end up in the lake,” Prof Tareq added. The bio-concentration factor (BCF) analysis reveals that among all the fish species, Labeo bata and Oreochromis mossambicus accumulate the highest number of microplastics from the lake environment.
The pollution load index of MPs indicates that the sampling sites were within hazard levels III-IV. Estimated annual intake reveals that humans will be exposed to the highest number of microplastics if they consume the fleshes, the study said. All laboratory procedures were conducted at the hydro biogeochemistry and pollution control laboratory, the Department of Environmental Sciences, Jahangirnagar University. Despite a ban on plastic bags in the country since 2002, some 3,000 factories are producing 14 million polythene bags in the country, according to a report presented recently by the Bangladesh Sustainability Alliance. Between 2005 and 2020, per capita consumption of plastic products in Bangladesh increased from 03 kg to 09 kg, with a significant portion ending up in land and rivers, it added, saying that of the total plastic waste in Dhaka, 15 per cent end up in rivers, canals and drains. According to the Environment and Social Development Organisation, fresh water bodies received 7928 billion microbeads monthly.