Paniek over microplastics heeft geen wetenschappelijke basis

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‘A bombshell’: doubt cast on discovery of microplastics throughout human body

Damian Carrington Environment editor
Tue 13 Jan 2026 15.20 CET

High-profile studies reporting the presence of microplastics throughout the human body have been thrown into doubt by scientists who say the discoveries are probably the result of contamination and false positives. One chemist called the concerns “a bombshell”.

Studies claiming to have revealed micro and nanoplastics in the brain, testes, placentas, arteries and elsewhere were reported by media across the world, including the Guardian. There is no doubt that plastic pollution of the natural world is ubiquitous, and present in the food and drink we consume and the air we breathe. But the health damage potentially caused by microplastics and the chemicals they contain is unclear, and an explosion of research has taken off in this area in recent years.

However, micro- and nanoplastic particles are tiny and at the limit of today’s analytical techniques, especially in human tissue. There is no suggestion of malpractice, but researchers told the Guardian of their concern that the race to publish results, in some cases by groups with limited analytical expertise, has led to rushed results and routine scientific checks sometimes being overlooked.

The Guardian has identified seven studies that have been challenged by researchers publishing criticism in the respective journals, while a recent analysis listed 18 studies that it said had not considered that some human tissue can produce measurements easily confused with the signal given by common plastics.

There is an increasing international focus on the need to control plastic pollution but faulty evidence on the level of microplastics in humans could lead to misguided regulations and policies, which is dangerous, researchers say. It could also help lobbyists for the plastics industry to dismiss real concerns by claiming they are unfounded. While researchers say analytical techniques are improving rapidly, the doubts over recent high-profile studies also raise the questions of what is really known today and how concerned people should be about microplastics in their bodies.
‘The paper is a joke’
Microplastics

“Levels of microplastics in human brains may be rapidly rising” was the shocking headline reporting a widely covered study in February. The analysis, published in a top-tier journal and covered by the Guardian, said there was a rising trend in micro- and nanoplastics (MNPs) in brain tissue from dozens of postmortems carried out between 1997 and 2024.

However, by November, the study had been challenged by a group of scientists with the publication of a “Matters arising” letter in the journal. In the formal, diplomatic language of scientific publishing, the scientists said: “The study as reported appears to face methodological challenges, such as limited contamination controls and lack of validation steps, which may affect the reliability of the reported concentrations.”
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One of the team behind the letter was blunt. “The brain microplastic paper is a joke,” said Dr Du¨an Materić, at the Helmholtz Centre for Environmental Research in Germany. “Fat is known to make false-positives for polyethylene. The brain has [approximately] 60% fat.” Materić and his colleagues suggested rising obesity levels could be an alternative explanation for the trend reported in the study.

Materić said: “That paper is really bad, and it is very explainable why it is wrong.” He thinks there are serious doubts over “more than half of the very high impact papers” reporting microplastics in biological tissue.

Prof Matthew Campen, senior author of the brain study in question, told the Guardian: “In general, we simply find ourselves in an early period of trying to understand the potential human health impacts of MNPs and there is no recipe book for how to do this. Most of the criticism aimed at the body of work to date (ie from our lab and others) has been conjectural and not buffeted by actual data.

“We have acknowledged the numerous opportunities for improvement and refinement and are trying to spend our finite resources in generating better assays and data, rather than continually engaging in a dialogue.”
‘Bombshell’ doubts
Microplastics in the body

But the brain study is far from alone in having been challenged. One, which reported that patients with MNPs detected in carotid artery plaques had a higher risk of heart attacks and strokes than patients with no MNPs detected, was subsequently criticised for not testing blank samples taken in the operating room. Blank samples are a way of measuring how much background contamination may be present.

Another study reported MNPs in human testes, “highlighting the pervasive presence of microplastics in the male reproductive system”. But other scientists took a different view: “It is our opinion that the analytical approach used is not robust enough to support these claims.”

This study was by Prof Campen and colleagues, who responded: “To steal/modify a sentiment from the television show Ted Lasso, ‘[Bioanalytical assays] are never going to be perfect. The best we can do is to keep asking for help and accepting it when you can and if you keep on doing that, you’ll always be moving toward better.’”

Further challenged studies include two reporting plastic particles in blood – in both cases the researchers contested the criticisms – and another on their detection in arteries. A study claiming to have detected 10,000 nanoplastic particles per litre of bottled water was called “fundamentally unreliable” by critics, a charge disputed by the scientists.

The doubts amount to a “bombshell”, according to Roger Kuhlman, a chemist formerly at the Dow Chemical Company. “This is really forcing us to re-evaluate everything we think we know about microplastics in the body. Which, it turns out, is really not very much. Many researchers are making extraordinary claims, but not providing even ordinary evidence.”

While analytical chemistry has long-established guidelines on how to accurately analyse samples, these do not yet exist specifically for MNPs, said Dr Frederic Béen, at Vrije Universiteit Amsterdam: “But we still see quite a lot of papers where very standard good laboratory practices that should be followed have not necessarily been followed.”

These include measures to exclude background contamination, blanks, repeating measurements and testing equipment with samples spiked with a known amount of MNPs. “So you cannot be assured that whatever you have found is not fully or partially derived from some of these issues,” Béen said.

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Prof Matthew Campen, senior author of the brain study in question, told the Guardian: “In general, we simply find ourselves in an early period of trying to understand the potential human health impacts of MNPs and there is no recipe book for how to do this. Most of the criticism aimed at the body of work to date (ie from our lab and others) has been conjectural and not buffeted by actual data.

“We have acknowledged the numerous opportunities for improvement and refinement and are trying to spend our finite resources in generating better assays and data, rather than continually engaging in a dialogue.”

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Op woensdag 14 januari 2026 10:39 schreef butz0rs het volgende:
Ik wil ze wel eens een lepel microplastics zien opeten