Microplastics found in your brain, in the placenta, in your big toe! Roaring heads that scared us all. Are our bodies really full of plastic? Well, that hasn’t been said yet: the studies on the subject are flawed on all sides, researchers argue in The Guardian.
The race to publish groundbreaking results has led to hasty conclusions where standard scientific checks have sometimes been skipped and the quality of the analyzes has left much to be desired, critics say. Key points: The measurements may have confused adipose tissue with microplastics-found-in-tea-bags-a-new-frontier-in-pollution-research/” title=”… Found in Tea Bags: A New Frontier in Pollution Research”>nanoplastics. These nanoplastics are also so small that we can barely detect them and it is unlikely that the slightly larger macroplastics end up in the bloodstream.
False positive results
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Official criticism has appeared in all kinds of scientific journals. For example, there was an important study in February last year that identified an increasing trend of nano- and microplastics in the human brain. However, in November the study was undermined by a group of scientists who wrote that there were all kinds of methodological flaws in the research. One of the researchers, Dr. Dušan Materić from the Helmholtz Center for Environmental Research in Germany, wrote very directly: “The microplastics-in-the-brain article is a joke.” He explains: “Fat tissue is known to give false positive results for polyethylene. The brain is made up of about 60 percent fat.” The researchers suggested that rising obesity rates may be an alternative explanation for the trend reported in the study. Materić responds: “That article is really bad and it is very easy to explain why it is incorrect.” In fact, he thinks there are serious doubts about “more than half of the highly influential papers” reporting microplastics in biological tissue.
The brain study therefore does not stand alone. Another study, which found micro- and nanoplastics in carotid artery plaques, was later criticized for not testing blank samples taken in the operating room. Blank samples are a way to measure how much background contamination may be present.
Another study reported micro- and nanoplastics in human testicles, highlighting “the ubiquitous presence of microplastics in the male reproductive system.” Other scientists disagreed: “It is our view that the analytical approach used is not robust enough to support these claims.” And so it goes on: research claiming there are 10,000 nanoplastics in a liter of bottled water was called ‘fundamentally unreliable’ by experts.
Methodological mistakes
According to Dr. Frederic Béen of the Vrije Universiteit Amsterdam, many things are going wrong with research into micro- and nanoplastics in the human body. “We continue to see quite a few articles where standard laboratory practices have not been adhered to.” This includes measures to exclude background contamination, the use of blank samples, repeating measurements and testing equipment with samples to which a known amount of micro- and nanoplastics has been added. “So you cannot be sure that what you have found does not arise in whole or in part from one of these problems,” Béen explains.
An important way to measure the amount of plastics in a sample is to evaporate it and then collect the vapors. However, this method has been strongly criticized. “This technique is currently not suitable for identifying polyethylene or PVC due to persistent interference,” concluded a study from the University of Queensland in Australia.
“I really think this is a problem across the entire field,” said Dr. Cassandra Rauert of the Australian university in The Guardian. “I think many of the concentrations that are being reported are completely unrealistic.” The problem is that some of the small molecules in the fumes that come from polyethylene and PVC can also be produced from fats in human tissue. This creates false positive results.
No microplastics
But Rauert doubts the findings on an even more fundamental level. “I have seen no evidence that particles between 3 and 30 micrometers can enter the bloodstream,” she said. “Based on what we know about actual exposure in everyday life, it is not biologically plausible that that amount of plastic actually ends up in these organs. It is really only the nanoplastics – smaller than 1 micrometer – that can cross biological barriers and that we expect in humans. But the current instruments we have cannot detect nanoparticles.”
Plastic production has increased by a factor of 200 since the 1950s and is expected to nearly triple to more than a billion tons per year by 2060. As a result, plastic pollution has also increased dramatically, with 8 billion tons now polluting the planet. Less than 10 percent of plastic is recycled. No one denies that plastic pollution is a problem, but how much ends up in the human body and whether it is harmful remains a big question mark. In that respect, the current measurements are irresponsible and can lead to fear-mongering, according to Rauert. “We want to get the data right so that we can properly inform our health authorities, governments and the public and ensure that the right regulations and policies are put in place.”
Afraid of plastic
In the meantime, we are all becoming increasingly afraid of plastic. There are already insane treatments available, sometimes costing more than 10,000 euros, that claim to remove microplastics from your blood. These claims have no scientific basis and depending on the equipment used, they can even introduce more plastic into people’s blood.
The good news, Béen concludes, is that analytical research using multiple techniques is improving rapidly. “I think there is less and less doubt that micro- and nanoplastics are present in tissues. The challenge is still to know exactly how much or in what quantity. But I think we are reducing this uncertainty further and further.”
We have written about this subject before, for example also read: A worrying amount of plastic found in the stomachs of Mediterranean seabirds and How much plastic is needed to kill a porpoise or sea turtle? Much less than you think. Or read this article: We breathe in up to 68,000 microplastics every day: 100 times more than previous estimates.
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