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Plastic: lightweight, cheap and durable, it’s become a staple in households and industry. It may make our lives easier, but it also has the ability to enter our bodies and stick around. Whilst this isn’t a new concern – it’s been known for several years that plastic particles may take up residence in various bodily tissues, including the brain – researchers from the University of New Mexico have recently shown that the amount of plastic in our bodies may be rising over time.
As plastic (very slowly) breaks down, it fragments into increasingly tiny particles, termed “microplastics” by Professor Richard Thomas in 2004. These particles range in size from less than a nanometre (that’s just one millionth of a millimetre!) to around five hundred micrometres (μm), or half a millimetre. For comparison, the width of a human hair is around 100 micrometres, and the body of a human neuron measures roughly 6-80 micrometres in diameter. Despite some initial scepticism from academic colleagues, Professor Thompson and other researchers have shown that microplastics are everywhere – they’re in our oceans and the creatures that live in them, and in the ground, where they can wreak havoc on soil quality and plant health. We now know that microplastics are even in us – they have been found in a range of human tissues, from the spleen, liver and kidneys, to the heart and lungs. But how did they get there?
The exact mechanisms of entry and consequences of microplastics exposure are unknown, but they have been linked to worsened health outcomes in both humans and animals. In a study published in Nature Medicine earlier this year, a group of researchers led by Dr. Matthew Campen at the University of New Mexico compared microplastics in human tissue from individuals who passed away in 2016 vs 2024, and their findings were striking. They found that microplastics in liver tissue exhibited a 3-fold increase between these years, whilst the amount of microplastics in brain tissue was nearly 40% higher in 2024 than in 2016. The brain may be a particular concern: brain microplastic concentrations were 7-30 times higher than concentrations in the lungs and kidneys. In samples from dementia patients, microplastics in the brain were even further elevated, and although the researchers stress that a causal link can’t be drawn from this data alone, the pattern is enough to raise serious questions about the impacts of microplastics.
Part of this study’s success was the use of improved techniques to allow researchers to quantify even the tiniest of particles, which may have been missed by previous experiments. The team used mass spectrometry, a highly sensitive technique used to investigate individual components in a sample, and transmission electron microscopy, an imaging technique with incredibly high resolution. In this case, the mass spectrometry was combined with a heating step to break the sample into even smaller fragments for better analysis.
It had been assumed that microplastics accumulate in the body over the lifespan, but reassuringly, the study found no correlation between microplastic concentrations and age of death. And there might be more good news: research from the Chinese Academy of Science suggests that there may be a functional mechanism for clearing MNPs from the body. Their work with zebrafish found that the levels of plastic in their bodies reached a plateau even under constant levels of environmental exposure, and began to decline after exposure ended. The researchers suggest these points to a natural mechanism for removing microplastics from the body over time. However, similar research has not yet been performed in mammals.
This new research adds to the growing evidence that an increasing amount of plastic is not only polluting the environment, but also human organs, in particular the brain. Nevertheless, many questions remain regarding how microplastics enter the body, if (or how) they leave and what the long-term effects are. In a world where plastic exposure is impossible to avoid, research like this brings us one step closer to understanding the true impact of plastic on human health.
Article written by Fizzy Hunter, a former Integrative Neurosciences master‘s student at the University of Edinburgh.
Article edited by Eleanor Stamp, a Neuroscience PhD student at the Institute of Genetics and Cancer, University of Edinburgh, and an Online News Editor for EUSci.
Resources:
Article:
Nihart, A. J., Garcia, M. A., El Hayek, E., Liu, R., Olewine, M., Kingston, J. D., Castillo, E. F., Gullapalli, R. R., Howard, T., Bleske, B., Scott, J., Gonzalez-Estrella, J., Gross, J. M., Spilde, M., Adolphi, N. L., Gallego, D. F., Jarrell, H. S., Dvorscak, G., Zuluaga-Ruiz, M. E., West, A. B., … Campen, M. J. (2025). Bioaccumulation of microplastics in decedent human brains. Nature medicine, 31(4), 1114–1119. https://doi.org/10.1038/s41591-024-03453-1
Other sources:
Microplastics information:
Kozlov, M. (2025, February 11). Your brain is full of microplastics: are they harming you? https://www.nature.com/articles/d41586-025-00405-8
Li, Y., Chen, L., Zhou, N., Chen, Y., Ling, Z., & Xiang, P. (2024). Microplastics in the human body: A comprehensive review of exposure, distribution, migration mechanisms, and toxicity. The Science of the total environment, 946, 174215. https://doi.org/10.1016/j.scitotenv.2024.174215
Habumugisha, T., Zhang, Z., Fang, C., Yan, C., & Zhang, X. (2023). Uptake, bioaccumulation, biodistribution and depuration of polystyrene nanoplastics in zebrafish (Danio rerio). The Science of the total environment, 893, 164840. https://doi.org/10.1016/j.scitotenv.2023.164840
Carrington, D. (2022, March 24). Microplastics found in human blood for the first time. https://www.theguardian.com/environment/2022/mar/24/microplastics-found-in-human-blood-for-first-time
Thompson, R. C., Olsen, Y., Mitchell, R. P., Davis, A., Rowland, S. J., John, A. W., McGonigle, D., & Russell, A. E. (2004). Lost at sea: where is all the plastic?. Science, 304(5672), 838. https://doi.org/10.1126/science.1094559
Stats cited in this article:
Raine CS. Characteristics of the Neuron. In: Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999. Available from: https://www.ncbi.nlm.nih.gov/books/NBK28209/
More information about the methods used in this study:
Winey, M., Meehl, J. B., O’Toole, E. T., & Giddings, T. H., Jr (2014). Conventional transmission electron microscopy. Molecular biology of the cell, 25(3), 319–323. https://doi.org/10.1091/mbc.E12-12-0863
EAG Laboratories. Pyrolysis Gas Chromatography/Mass Spectrometry (Pyro-GC-MS). https://www.eag.com/techniques/mass-spec/pyrolysis-gc-ms/
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