A wave of alarming headlines about microplastics and nano plastics accumulating in human brains, testes, placentas and arteries may have been built on shaky scientific ground.
That is according to leading experts who warn of methodological flaws.
An investigation by UK newspaper The Guardian on January 13 highlighted concerns that many such detections may result from laboratory contamination, inadequate controls or misinterpretation of analytical signals rather than genuine particle accumulation.
Scientists interviewed described the issues as significant, with one former industry chemist characterising the doubts as “a bombshell” and suggesting problems affect a substantial portion of prominent papers in the field.
The main criticisms focus on insufficient blank controls and contamination safeguards during sample handling and analysis, given the ubiquity of plastic particles in lab environments.
They also point to the use of spectroscopic methods that can produce false positives by confusing biological components, such as lipids or proteins, with plastics like polyethylene.
There were also reported concentrations that some researchers view as biologically implausible based on known human exposure pathways.
The rapid rise in such studies, often rushed to publication amid intense public and policy interest in plastic pollution, has fuelled media frenzy and calls for drastic regulatory action across the European Union.
Yet several of the most cited findings are now facing formal challenges in journals, with experts arguing the results stem from artefacts rather than genuine accumulation.
The UK newspaper identified seven studies that have been challenged by researchers through published criticisms in the respective journals.
Additionally, a recent analysis flagged 18 studies for not accounting for the fact that some human tissues can generate measurements easily confused with signals from common plastics, potentially leading to false positives.
Still, no one disputes that microplastics are ubiquitous in the environment, entering air, food and water supplies worldwide.
The particles are ingested and inhaled daily and their presence in wildlife and ecosystems is well documented.
Accurately quantifying ultra-trace levels in complex human samples, though, remains technically demanding.
Laboratories are rife with plastic equipment and airborne fibres, making rigorous blank controls and validation essential – steps many recent papers appear to have skimped on as highlighted in the Nature Medicine study Matters Arising.
Dr Dušan Materić, who co-wrote the study, went so far as to say one paper on microplastics in the brain “is a joke” and stressed that fat can generate false-positives for polyethylene.
He stated there are serious doubts over “more than half of the very high impact papers” reporting microplastics in biological tissue.
One prominent example is a study that reported patients with micro and nanoplastics (MNPs) detected in carotid artery plaques had a higher risk of heart attacks and strokes than those with no MNPs detected.
This was subsequently criticised for not testing blank samples taken in the operating room, a standard method for measuring background contamination levels.
Scientists stress that improving the reliability of MNP measurements in human tissues is crucial.
Dr Cassandra Rauert, who receives frequent queries about plastic levels in bodies, stressed that poor-quality data is irresponsible, risks scaremongering, and can fuel unnecessary public worry.
Rauert noted that robust science is essential to inform health agencies, governments, and policies accurately, while debunking unproven “blood-cleansing” treatments – some costing £10,000 (€8,666) – that lack evidence and may even add more plastic.
Experts recommend simple precautions for people who are worried, such as avoiding heating food in plastic containers, using fewer plastic bottles, ventilating homes and filtering water.
Such measures could lower exposure without panic, they say, while pleading for continued rigorous research to clarify long-term health effects.
The controversy echoes a familiar pattern in emerging environmental science where preliminary or flawed work generates outsized fear spurring disproportionate policy responses and only later does sober scrutiny reveal the limitations.
Brussels has already moved aggressively on plastic pollution, including restrictions on intentional microplastic use. New rules target pellets, single-use items and broader production caps under the EU’s circular economy and zero-pollution ambitions.
