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 \u201ca bombshell\u201d.<\/p>\n
Studies claiming to have revealed micro and nanoplastics in the brain<\/a>, testes<\/a>, placentas<\/a>, arteries<\/a> 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.<\/p>\n However, micro- and nanoplastic particles are tiny and at the limit of today\u2019s 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.<\/p>\n 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.<\/p>\n 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.<\/p>\n \u2018The paper is a joke\u2019<\/p>\n \u201cLevels of microplastics in human brains may be rapidly rising\u201d was the shocking headline reporting a widely covered study in February. The analysis, published in a top-tier journal<\/a> and covered by the Guardian<\/a>, said there was a rising trend in micro- and nanoplastics (MNPs) in brain tissue from dozens of postmortems carried out between 1997 and 2024.<\/p>\n However, by November, the study had been challenged by a group of scientists with the publication of a \u201cMatters arising\u201d letter<\/a> in the journal. In the formal, diplomatic language of scientific publishing, the scientists said: \u201cThe 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.\u201d<\/p>\n One of the team behind the letter was blunt<\/a>. \u201cThe brain microplastic paper is a joke,\u201d said Dr Du\u0161an Materi\u0107, at the Helmholtz Centre for Environmental Research in Germany. \u201cFat is known to make false-positives for polyethylene. The brain has [approximately] 60% fat.\u201d Materi\u0107 and his colleagues suggested rising obesity levels could be an alternative explanation for the trend reported in the study.<\/p>\n Materi\u0107 said: \u201cThat paper is really bad, and it is very explainable why it is wrong.\u201d He thinks there are serious doubts over \u201cmore than half of the very high impact papers\u201d reporting microplastics in biological tissue.<\/p>\n Prof Matthew Campen, senior author of the brain study in question, told the Guardian: \u201cIn 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.<\/p>\n \u201cWe 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.\u201d<\/p>\n \u2018Bombshell\u2019 doubts<\/p>\n But the brain study is far from alone in having been challenged. One, which reported that patients with MNPs detected in carotid artery plaques<\/a> had a higher risk of heart attacks<\/a> and strokes than patients with no MNPs detected, was subsequently criticised for not testing blank samples<\/a> taken in the operating room. Blank samples are a way of measuring how much background contamination may be present.<\/p>\n Another study reported MNPs in human testes<\/a>, \u201chighlighting the pervasive presence of microplastics in the male reproductive system\u201d. But other scientists took a different view<\/a>: \u201cIt is our opinion that the analytical approach used is not robust enough to support these claims.\u201d<\/p>\n This study was by Prof Campen and colleagues, who responded: \u201cTo steal\/modify a sentiment from the television show Ted Lasso, \u2018[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\u2019ll always be moving toward better.\u2019\u201d<\/p>\n Further challenged studies include two<\/a> reporting plastic particles<\/a> in blood<\/a> \u2013 in both cases the researchers contested the criticisms<\/a> \u2013 and another on their detection<\/a> in arteries<\/a>. A study claiming to have detected 10,000 nanoplastic particles<\/a> per litre of bottled water was called \u201cfundamentally unreliable<\/a>\u201d by critics, a charge disputed by the scientists<\/a>.<\/p>\n The doubts amount to a \u201cbombshell\u201d, according to Roger Kuhlman, a chemist formerly at the Dow Chemical Company. \u201cThis 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.\u201d<\/p>\n While analytical chemistry has long-established guidelines on how to accurately analyse samples, these do not yet exist specifically for MNPs, said Dr Frederic B\u00e9en, at Vrije Universiteit Amsterdam: \u201cBut we still see quite a lot of papers where very standard good laboratory practices that should be followed have not necessarily been followed.\u201d<\/p>\n These include measures to exclude background contamination, blanks, repeating measurements and testing equipment with samples spiked with a known amount of MNPs. \u201cSo you cannot be assured that whatever you have found is not fully or partially derived from some of these issues,\u201d B\u00e9en said.<\/p>\n Biologically implausible<\/p>\n A key way of measuring the mass of MNPs in a sample is, perhaps counterintuitively, vaporising it, then capturing the fumes. But this method, dubbed Py-GC-MS, has come under particular criticism. \u201c[It] is not currently a suitable technique for identifying polyethylene or PVC due to persistent interferences,\u201d concluded a January 2025 study<\/a> led by Dr Cassandra Rauert, an environmental chemist at the University of Queensland in Australia.<\/p>\n \u201cI do think it is a problem in the entire field,\u201d Rauert told the Guardian. \u201cI think a lot of the concentrations [of MNPs] that are being reported are completely unrealistic.\u201d<\/p>\n \u201cThis isn\u2019t a dig at [other scientists],\u201d she added. \u201cThey use these techniques because we haven\u2019t got anything better available to us. But a lot of studies that we\u2019ve seen coming out use the technique without really fully understanding the data that it\u2019s giving you.\u201d She said the failure to employ normal quality control checks was \u201ca bit crazy\u201d.<\/p>\n Py-GC-MS begins by pyrolysing the sample \u2013 heating it until it vaporises. The fumes are then passed through the tubes of a gas chromatograph, which separates smaller molecules from large ones. Last, a mass spectrometer uses the weights of different molecules to identify them.<\/p>\n The problem is that some small molecules in the fumes derived from polyethylene and PVC can also be produced from fats in human tissue. Human samples are \u201cdigested\u201d with chemicals to remove tissue before analysis, but if some remains the result can be false positives for MNPs. Rauert\u2019s paper lists 18 studies that did not include consideration of the risk of such false positives.<\/p>\n Rauert also argues that studies reporting high levels of MNPs in organs are simply hard to believe: \u201cI have not seen evidence that particles between 3 and 30 micrometres can cross into the blood stream,\u201d she said. \u201cFrom what we know about actual exposure in our everyday lives, it is not biologically plausible that that mass of plastic would actually end up in these organs.\u201d<\/p>\n \u201cIt\u2019s really the nano-size plastic particles that can cross biological barriers and that we are expecting inside humans,\u201d she said. \u201cBut the current instruments we have cannot detect nano-size particles.\u201d<\/p>\n Further criticism came in July, in a review study in the Deutsches \u00c4rzteblatt<\/a>, the journal of the German Medical Association. \u201cAt present, there is hardly any reliable information available on the actual distribution of microplastics in the body,\u201d the scientists wrote.<\/p>\n Fresh blood<\/p>\n Plastic production has ballooned by 200 times since the 1950s and is set to almost triple again to more than a billion tonnes a year by 2060. As a result, plastic pollution has also soared, with 8bn tonnes now contaminating the planet from the top of Mount Everest<\/a> to the deepest ocean trench<\/a>. Less than 10% of plastic is recycled.<\/p>\n An expert review published in the Lancet<\/a> in August called plastics a \u201cgrave, growing and underrecognised danger\u201d to human and planetary health. It cited harm from the extraction of the fossil fuels they are made from, to their production, use and disposal, which result in air pollution and exposure to toxic chemicals.<\/p>\n In recent years, the infiltration of the body with MNPs has become a serious concern, and a landmark study<\/a> in 2022 first reported detection in human blood<\/a>. That study is one of the 18 listed in Rauert\u2019s paper and was criticised by Kuhlman<\/a>.<\/p>\n But the study\u2019s senior author, Prof Marja Lamoree, at Vrije Universiteit Amsterdam, rejected suggestions of contamination. \u201cThe reason we focused on blood in the first place is that you can take blood samples freshly, without the interference of any plastics or exposure to the air,\u201d she said.<\/p>\n \u201cI\u2019m convinced we detected microplastics,\u201d she said. \u201cBut I\u2019ve always said that [the amount estimated] could be maybe twice lower, or 10 times higher.\u201d In response to Kuhlman\u2019s letter, Prof Lamoree and colleagues said he had \u201cincorrectly interpreted<\/a>\u201d the data.<\/p>\n Prof Lamoree does agree there is a wider issue. \u201cIt\u2019s still a super-immature field and there\u2019s not many labs that can do [these analyses well]. When it comes to solid tissue samples tissues, then the difficulty is they are usually taken in an operating theatre that\u2019s full of plastic.\u201d<\/p>\n \u201cI think most of the, let\u2019s say, lesser quality analytical papers come from groups that are medical doctors or metabolomics [scientists] and they\u2019re not driven by analytical chemistry knowledge,\u201d she said.<\/p>\n Scaremongering<\/p>\n Improving the quality of MNP measurements in the human body matters, the scientists said. Poor quality evidence is \u201cirresponsible\u201d and can lead to scaremongering, said Rauert: \u201cWe want to be able to get the data right so that we can properly inform our health agencies, our governments, the general population and make sure that the right regulations and policies are put in place.<\/p>\n \u201cWe get a lot of people contacting us, very worried about how much plastics are in their bodies,\u201d she said. \u201cThe responsibility [for scientists] is to report robust science so you are not unnecessarily scaring the general population.\u201d<\/p>\n Rauert called treatments claiming to clean microplastics from your blood \u201ccrazy\u201d \u2013 some are advertised for \u00a310,000. \u201cThese claims have no scientific evidence,\u201d she said, and could put more plastic into people\u2019s blood, depending on the equipment used.<\/p>\n Materi\u0107 said insufficiently robust studies might also help lobbyists for the plastics industry downplay known risks of plastic pollution.<\/p>\n The good news, said B\u00e9en, is that analytical work across multiple techniques is improving rapidly: \u201cI think there is less and less doubt about the fact that MNPs are there in tissues. The challenge is still knowing exactly how many or how much. But I think we\u2019re narrowing down this uncertainty more and more.\u201d<\/p>\n Prof Lamoree said: \u201cI really think we should collaborate on a much nicer basis \u2013 with much more open communication \u2013 and don\u2019t try to burn down other people\u2019s results. We should all move forward instead of fighting each other.\u201d<\/p>\n \u2018On the safe side\u2019<\/p>\n In the meantime, should the public be worried about MNPs in their bodies?<\/p>\n Given the very limited evidence, Prof Lamoree said she could not say how concerned people should be: \u201cBut for sure I take some precautions myself, to be on the safe side. I really try to use less plastic materials, especially when cooking or heating food or drinking from plastic bottles. The other thing I do is ventilate my house.\u201d<\/p>\n \u201cWe do have plastics in us \u2013 I think that is safe to assume,\u201d said Materi\u0107. \u201cBut real hard proof on how much is yet to come. There are also very easy things that you can do to hugely reduce intake of MNPs. If you are concerned about water, just filtering through charcoal works.\u201d Experts also advise avoiding food or drink<\/a> that has been heated in plastic containers.<\/p>\n Rauert thinks most of the MNPs that people ingest or breathe in are probably expelled by their bodies, but said it can\u2019t hurt to reduce your plastics exposure. Furthermore, she said, it remains vital to resolve the uncertainty over what MNPs are doing to our health: \u201cWe know we\u2019re being exposed, so we definitely want to know what happens after that and we\u2019ll keep working at it, that\u2019s for sure.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"High-profile studies reporting the presence of microplastics throughout the human body have been thrown into doubt by scientists…\n","protected":false},"author":3,"featured_media":515050,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[51,50,52],"class_list":{"0":"post-515049","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-news","8":"tag-headlines","9":"tag-news","10":"tag-top-stories"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115892457751422813","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/515049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=515049"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/515049\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/515050"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=515049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=515049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=515049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}