Soybean oil sold in Bangladesh contains alarming levels of microplastic contamination, with researchers detecting an average of nearly 54,000 plastic particles per liter in both branded and loose varieties, according to a new study.
The findings, published in the April 2026 issue of the peer-reviewed Journal of Food Composition and Analysis, raise fresh concerns about food safety and the long-term public health impacts of microplastic exposure.
The study, conducted jointly by researchers from Jahangirnagar University (JU) and Bangladesh University of Professionals (BUP), found that loose soybean oil contains significantly higher levels of microplastics than bottled oil.
Researchers say it is the first scientific investigation into microplastic contamination in edible oil in Bangladesh and the first globally to identify polyurethane (PU) and nylon microplastics in edible oil.
The researchers found an average of 53,922 (±10,510) microplastic particles per liter in soybean oil samples collected from markets in Dhaka.
Loose soybean oil contained an average of 59,778 particles per liter, compared with 48,067 particles in bottled oil, making contamination in loose oil about 1.24 times higher.
The highest contamination level was recorded in a loose oil sample collected from Tejgaon, where researchers detected 70,467 microplastic particles per liter.
The researchers believe the higher contamination may be linked to Tejgaon's concentration of plastic and textile industries, airborne synthetic fibers, repeated use of plastic storage containers, and exposure to open environments during storage and sale.
How the study was conducted
The researchers collected 60 one-liter soybean oil samples comprising three branded (bottled) and three non-branded (loose) varieties from supermarkets and open markets in Tejgaon, Uttara, and Dhaka Cantonment.
The samples were divided into six categories. Ten samples from each category were combined into a composite sample, producing six composite samples for laboratory analysis.
Each composite sample was analyzed three times using solvent dilution, stereo microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) to ensure the accuracy and reliability of the findings.
Lead researcher Prof Shafi Mohammad Tareq of JU's Department of Environmental Sciences told Dhaka Tribune that the team analyzed both branded and loose soybean oil available in Dhaka's markets.
"Our analysis found thousands of microplastic particles per liter in both types of oil, with fibers and fragments accounting for the majority of the contamination," he said.
Six types of plastic identified
The study identified six polymer types in the oil samples: low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET), polyurethane (PU), and nylon.
The detection of polyurethane and nylon is particularly significant, as the researchers say these polymers have never before been reported in edible oil.
They believe polyurethane may originate from industrial coatings and adhesives, while nylon could enter oil through filters, nets, or manufacturing equipment.
More than 82% of the detected microplastics were fibers, while fragments accounted for nearly 10%. Transparent particles were the most common, representing more than 56% of the total. Most particles measured between 101 and 500 micrometers.
Children face the greatest exposure risk
The researchers also carried out a Human Exposure Assessment to estimate how many microplastic particles people could ingest through regular soybean oil consumption.
The estimates were based on average soybean oil consumption in Bangladesh, assuming an average adult body weight of 70kg and a child's average weight of 16kg.
According to the assessment, an adult could ingest an average of 17.65 microplastic particles a day through soybean oil alone. This amounts to about 6,441 particles a year and an estimated 477,000 particles over a lifetime.
The potential exposure is considerably higher for children because of their lower body weight. The study estimates that a child could ingest an average of 77.21 microplastic particles daily, about 28,180 annually, and nearly 2.09 million particles over a lifetime.
The researchers cautioned that these figures are model-based estimates rather than direct measurements of microplastics in the human body.
Public health concerns
Prof Tareq said microplastics are increasingly regarded as an "emerging contaminant" with potentially serious long-term health implications.
"Microplastics can enter edible oil during production, processing, transportation, storage, and packaging," he said.
He added that plastic pipes, filters, seals, and packaging materials used throughout the supply chain are among the likely sources of contamination.
The study notes that previous research has linked long-term ingestion of microplastics to digestive disorders, inflammation, cellular damage, hormonal disruption, metabolic disorders, and reproductive health concerns.
It also notes that particles smaller than 130 micrometers may cross biological barriers and enter the bloodstream, although scientists say more research is needed to fully understand their long-term health effects in humans.
Public health expert Dr Shamsur Rahman described microplastics as an emerging public health challenge.
He said studies around the world have detected microplastics in the human brain, lungs, liver, kidneys, stomach, testes, and ovaries.
"Harmful chemicals attached to these particles may increase cancer risks and damage vital organs, including the liver and kidneys," he said.
Regulatory gaps
The researchers say Bangladesh currently lacks national standards or routine monitoring systems for microplastic contamination in food products.
As a result, they say reliable national data on contamination levels, exposure pathways, and long-term health impacts remain limited.
Dr Rahman said stricter quality control is needed throughout the food supply chain, along with modern laboratories and stronger government oversight to regularly monitor microplastic contamination in food.
Although all six sample groups fell within the "moderate pollution" category under the study's Microplastic Pollution Index (MPI), the researchers cautioned that the index is intended only to compare contamination levels between samples and should not be interpreted as an official food safety standard.
Recommendations
The researchers called for coordinated national action to reduce microplastic contamination throughout the edible oil supply chain.
They recommended strengthening quality control during production and refining, replacing plastic equipment with safer alternatives where possible, tightening oversight of loose oil storage and sales, introducing national monitoring standards for microplastics in food, investing in laboratory capacity, and expanding plastic waste management and recycling programs.
"Simply raising public awareness will not be enough," Prof Tareq said.
"Producers, regulators, and policymakers must work together to identify and reduce contamination sources from production to consumers' tables. Without coordinated action, the health and economic consequences of microplastic pollution could become much more severe in the future."
