*IMPORTANT CONTEXT BEFORE WE CONTINUE*

When you see a press headline, it doesn’t necessarily mean that that's what the study actually said. Such as the most recent plastics in brain media frenzy. If people knew more about the uncertainty of what we actually can and can't measure in the environment in terms of microplastics, and the fact that there isn't necessarily any proven harm to humans generally, it would help. Plastics have been around, with widespread use, since the 1950s and we're all still here. In fact, most people are living longer and healthier lives than we did 50 years ago. That is, in some ways, due to plastics—helping us preserve our food, in medicine, etc

When talking about material environmental impacts, when thinking about the blanket plastic vilification, it’s important to weigh plastic impacts against their alternatives. While with plastic, the focus is often on end of life, with other materials, often their beginning of lives are more intensive at other parts of their life cycles. When talking about environmentally superior packaging, it’s complex and it depends. If we stopped using all plastic in favor of "eco" alternatives (glass, paper, aluminum)... We would need: 3.6x the material, 2.2x the energy, with an increase of 2.7x the CO2 emissions. Surely we are overusing plastic in many areas, and that’s a problem, particularly with single use plastics.

Microplastics - What are they?

As early as the 1970s microplastics were found in coastal waters. It wasn’t until 2004 when “microplastic” was first used to describe them. As per the REACH definition, these are particles containing solid polymer, to which additives or other substances may have been added, and where ≥ 1% w/w of particles have (i) all dimensions 0.1µm ≤ x ≤ 5mm, or (ii) a length of 0.3µm ≤ x ≤ 15mm and length to diameter ratio of >3. Under this definition, particles are exempt if they are Natural polymers that have not been chemically modified, are (bio)degradable, or have a solubility > 2 g/L, according to the criteria in Appendix Y. Key Words: Small, Solid, Not Water-Soluble, Persistant. Plastics have broad usefulness, durability, and low cost. Their durability also represents a challenge in the environment.

Microplastics are categorized as:

Primary: ones created at a small size to begin with. E.g. glitter, microbeads.

Secondary: ones that result from bigger pieces of plastic breaking down over time.

Most microplastic in the environment is secondary microplastic, however primary microplastics still significantly contribute to microplastic pollution. Plastics continue to break down in the environment due to abrasion against other solids, UV radiation, etc.

What do we know about them?

Microplastics in food and drinking water are a concern, though current evidence suggests they do not cross biological barriers easily. Contrary to media portrayals of the health impacts of microplastics, we do not understand their potential health implications very well. The World Health Organisation (WHO) says there's no conclusive proof that microplastics are causing a problem in the environment or to people, which isn't the same thing as to say that they definitely aren’t. They're just saying there isn't enough evidence to show that they are. A lot of the public panic on them is probably not matching up with the actual risk. That said, there’s a lot of plastic out in the environment. We can find seabirds that eat plastic, and they end up dying because they've filled their stomach with plastic and don’t have room for fish. Disclaimer, these are macro-plastics and not microplastics.

Nanoplastics (<1 micrometer) pose a greater unknown risk due to their smaller size and potential for biological uptake. Microplastic exposure from indoor air is likely at least twice as high as from drinking water or food. This is because most textiles, including carpeting, clothing, upholstery, and furniture, contain microplastics, making inhalation a potentially more significant source of exposure than ingestion. The microplastics may yet be found to be doing something, particularly the nanoplastics —because we know that air pollution of similarly sized particles (PM 2.5) can cause problems with breathing. The movement of inhaled particles into organs, including the brain, has been known for over 20 years but these are mostly carbon based particles e.g. from fires and industry.

The Challenge of measurement

Microplastics are quite tricky to measure. If you look at the literature on microplastics, people use different techniques to measure them (each with their own problems). They use different units to report what they found. There have been a number of studies that have found faults with some of the methods, so they give false positives, for example. There’s a lot of background microplastic contamination in the air, so it's very hard to find a lab that's completely microplastic-free. This creates a lot of uncertainty in the literature, and potentially some very overblown results that make it’s way to the media that fail to ever be replicated.

Microplastics are too big to put in mass spec, you have to break them down first. Because they're a hydrocarbon chain and you break them down into shorter hydrocarbon chains, they can be mistaken for fats in e.g. our body, which are also hydrocarbon chains. Sometimes is can be quite difficult to tell the difference. Another source for measurement error is with lab gloves, which can have stearate. There have been many cases where lab gloves give false microplastic readings for samples.

For example, one study claimed to find microplastics in the blood, but when they did their replicate samples, they got completely different readings. Unfortunately, study refutations like the ones below don’t go as far as the initial “MICROPLASTICS ARE IN YOUR BLOOD!” media headlines.

Similar story for this one that recently when viral :(. Again, unfortunately, once headlines like this are out, it’s hard to take back.

Oliver Jones PhD response to this paper from the Science Media Centre expert reaction submission:

“The authors tested 28 brain samples from 2016 and 24 from 2024, which is only 52 samples in total. There is not enough data to make firm conclusions on the occurrence of microplastics in New Mexico, let alone globally. Only data from 2 years – 2016 and 2024 are presented. It is not explained why only these two years were studied, but regardless, you simply can’t make a trend from data from just two years.

The main analytical method used in this study was pyrolysis gas chromatography-mass spectrometry. This method can give false results when used to measure plastics because fats (which the brain is mainly made of) give the same pyrolysis products as polyethylene (the main plastic reported). The authors did try to address this concern but I am not certain they were able to account for everything.

It is also challenging to properly account for potential contamination while handling or analysing samples in microplastic studies. This paper says that the findings are not likely to be lab contamination because samples were consistently handled and processed. I don’t think this is necessarily true. After all, consistent protocols could potentially result in consistent contamination. Even standard lab equipment, such as disposable lab gloves, can give false microplastic readings. We also don’t know what happened to the samples during the original autopsy (bodybags are made of polyethylene, for example). There is also the issue of background contamination in any laboratory that needs to be controlled for. Plastic contamination is almost everywhere, so how can we be confident that any particles found are evidence that plastic is crossing membranes in the human body or if it is just contamination from plastic in the clothes or lab equipment or background contamination in the air, etc?

While it is not impossible that there are microplastics in the brains of some people, this study does not prove that this occurs, and, as the authors themselves note, there is as yet no strong evidence of any health effects.”

Major Sources of Microplastics

Most microplastic in the environment is secondary microplastic, microplastic that results from bigger pieces of plastic breaking down in the environment.

If you look at wastewater, the major source of microplastics there appears to be clothing. Many of your clothes are made of plastic, and when you wash them, fibres break off and end up at wastewater treatment plants. A paper from Nottingham University argued that some of the fibers that have been called out as microplastics had been misidentified - some were e.g. natural fibers misidentified due to analytical equipment. Potentially, microplastics may not be as significant as people think - although, still, clearly an issue.

Microbeads and other microplastics from cosmetics make up only a VERY tiny proportion of microplastic pollution. Prior to the microbead bans, studies have calculated that roughly 0.1% of marine microplastic pollution in Europe, as an example, was from cosmetic product sources. Despite popular headlines, cosmetics aren’t a major contributor to microplastics, aside from maybe their packaging. This misdirected attention may be ultimately taking resources away from being able to effectively address the issue.

When you see a press headline, it doesn’t necessarily mean that that's what the study actually said. A press release talking about tens of thousands of particles in your food per year grabs attention far more than the plain, but also more accurately, “study finds we consume less than a millionth of a gram of plastic in our food per year”

The greater impact of Plastic Misinformation?

Misinformation diverts attention, resources, and policy efforts away from scientifically backed solutions and can result in decisions that ultimately harm both environmental sustainability and public health.

Policy Decisions Based on Poor Evidence

Misdirected Public Concern and Resources
Greenwashing and Ineffective Substitutes
Scientific Mistrust that makes it harder to implement meaningful sustainability initiatives
Unintended Consequences in environmental impact

For example, is banning plastic grocery bags in favour of fabric ones really a solution? Considering that a) fabric grocery bags are SIGNIFICANTLY more impactful to produce and b) they’re often being used as throwaways since people often forget them…they would have to be re-used ~150 times to break even with plastic bags, in terms of environmental impact. These policy actions can backfire when consumer behavior does not align with intended sustainability goals. Overconsumption is a massive problem, be it plastic or cloth bags.

The Cosmetics Context

When you go out and survey products for a whole bunch of extra things that fundementally are not plastic, yah, you’re going to get these kinds of scary numbers.

CRUCIALLY IMPORTANT: INCI names, the names on ingredient lists, do not tell you about physical properties. E.g. liquid polyethylene would be labelled as just “polyethylene”... which, by definition, is not a microplastic. YOU WILL NOT KNOW THIS JUST BY THE INGREDIENT LIST.

Back to reality

Historically microplastics have been used in both wash-off and leave on personal care products. Both, to varying degrees, are washed down drains, depending on the context. According to the ECHA (2019), the amount of leave-on products that ends up down the drain ranges from 15-90%. (That’s a huge range with lots of uncertainty due to the variety of formulations and inputs) Glitter, when found in leave-on products ends up in sewage at a rate of over 50%. While glitter is more widely used compared to microbeads, it hasn’t received the same attention in the literature, likely due to its density, which causes the glitter to sink in sediment. Since most microplastic samples are taken at the water's surface, and because microbeads typically have a low density, microbeads are more prominent in these samples.

Microbeads as exfoliants were first patented for cosmetics in 1972. They were rarely used until the 1990s when brands began replacing their natural abrasive materials, such as pumice peels, which are harsher on the skin and also more expensive. Within a decade, microbeads became so popular that in the United States, it was estimated that every household had at least one microbead-containing product which was used at least weekly.In North America, initial efforts for microbead limitations first started in the state of Illinois, followed by California. The Microbeads Free-Water Act was introduced in 2015, coming into effect in 2017. Several countries followed suit within the next couple of years. While some countries haven’t actively banned microbeads, the cosmetics industry at-large has phased out microbeads due to market pressure.

Today, microplastics aren’t actually that common in cosmetic formulations, however they can still be found here and there (if we’re using REACH’s definition), particularly in encapsulation systems and sunscreen technology. Currently there is talk about blanket bans for microplastics in many regions. What’s the potential problem with that?

1) efficacy/safety impact of products. Case example: Sunscreen. Depending on how you define microplastic, certain polymers used in sunscreens (e.g. SunSpheres) may be included - these ingredients help sunscreens have a better SPF with lower UV filter %. This translates to formulas that may be more esthetically pleasing to users with improved skin tolerability depending on the filters.

A blanket ban may have the unintended effect of less safe sunscreen - particularly in the USA where the sunscreen ingredients are already so limited. E.g. sunscreen benefits (reduced risk of skin cancer) hinge on sunscreen compliance; people actually have to wear enough of it regularly, which most people already don’t. For this, people actually have to like the products, otherwise they won't wear it or wear enough. The safest sunscreen for any individual will be the one they enjoy.

2) How are they being defined? Case example, California AB823. This should be a big reminder that legislators are not scientists and can be swayed with the same kind of misinformation the public is swayed by.

The issue of scapegoating cosmetics

Despite their VERY LOW contribution to microplastic pollution (again, less than 0.1% BEFORE the bans), most microplastic research has been focused on microbeads. The cosmetics industry has been pushed to phase out microplastics, which has proven effective globally; No other microplastic has had so many restrictions to date. Phasing out microbeads was a good thing, don’t get me wrong. HOWEVER, the misplaced attention of cosmetic microplastics has effectively diverted focus from larger environmental sources. This concept is called “misplaced conservation”, described in the figure below by Ford et al., (2021).

This post was based on my recent podcast episode on environmental contaminants and the impacts of misinformation on them. In conversation with professor and environmental contaminant researcher, Oliver Jones PhD. Tune into the full podcast here!

Additional References

Anagnosti, L., Varvaresou, A., Pavlou, P., Protopapa, E., & Carayanni, V. (2021). Worldwide actions against plastic pollution from microbeads and microplastics in cosmetics focusing on European policies. Has the issue been handled effectively?. Marine Pollution Bulletin, 162, 111883.

Andrady, A. L. (2011). Microplastics in the marine environment. Marine pollution bulletin, 62(8), 1596-1605.

Buchanan, J. B. (1971). Pollution by synthetic fibres. Marine Pollution Bulletin, 2(2), 23-23.

Cosmetics Europe. (2018). ECHA workshop 30–31st May 2018 intentionally added microplastics to products break-out session: cosmetics. ECHA Workshop Plenary Session 30th and 31st May 2018.

Department of the Environment and Energy. (2018). An Assessment of the Sale of Microbeads and Other Nonsoluble Plastic Polymers in Personal Care and Cosmetic Products Currently Available Within the Australian Retail (in Store) Market Department of the Environment and Energy, Canberra.

Ford, A. T., Ali, A. H., Colla, S. R., Cooke, S. J., Lamb, C. T., Pittman, J., ... & Singh, N. J. (2021). Understanding and avoiding misplaced efforts in conservation. Facets, 6(1), 252-271.

Gouin, T., Avalos, J., Brunning, I., Brzuska, K., De Graaf, J., Kaumanns, J., & Wolf, T. (2015). Use of micro-plastic beads in cosmetic products in Europe and their estimated emissions to the North Sea environment. SOFW J, 141(4), 40-46.

Kuhlman, R. L. (2022). Letter to the editor, discovery and quantification of plastic particle pollution in human blood. Environment international, 167, 107400-107400.

Kutralam-Muniasamy, G., Pérez-Guevara, F., Elizalde-Martínez, I., & Shruti, V. C. (2020). An overview of recent advances in micro/nano beads and microfibers research: Critical assessment and promoting the less known. Science of The Total Environment, 740, 139991.

Nemmar, A., Hoet, P. H., Vanquickenborne, B., Dinsdale, D., Thomeer, M., Hoylaerts, M. F., ... & Nemery, B. (2002). Passage of inhaled particles into the blood circulation in humans. Circulation, 105(4), 411-414.

Rauert, C., Charlton, N., Bagley, A., Dunlop, S. A., Symeonides, C., & Thomas, K. V. (2025). Assessing the Efficacy of Pyrolysis–Gas Chromatography–Mass Spectrometry for Nanoplastic and Microplastic Analysis in Human Blood. Environmental Science & Technology.

Rauert, C., Wang, X., Charlton, N., Lin, C. Y., Tang, C., Zammit, I., ... & Dunlop, S. (2024). Blueprint for the design, construction, and validation of a plastic and phthalate-minimised laboratory. Journal of Hazardous Materials, 468, 133803.

SAPEA (2019). A scientific perspective on microplastics in nature and society. Science Advice for Policy by European Academies, Berlin, 10.26356/microplastics

Stanton, T., Johnson, M., Nathanail, P., MacNaughtan, W., & Gomes, R. L. (2019). Freshwater and airborne textile fibre populations are dominated by ‘natural’, not microplastic, fibres. Science of the total environment, 666, 377-389.

Stoll, T., Stoett, O., Stoett, P., Vince, J., Hardesty, B. (2020). Governance and measures for the prevention of marine debris. Handbook of Microplastics in the Environment, Springer International Publishing.

Thompson, R. C., Olsen, Y., Mitchell, R. P., Davis, A., Rowland, S. J., John, A. W., ... & Russell, A. E. (2004). Lost at sea: where is all the plastic?. Science, 304(5672), 838-838.

Witzig, C. S., Földi, C., Wörle, K., Habermehl, P., Pittroff, M., Müller, Y. K., ... & Zumbülte, N. (2020). When good intentions go bad—false positive microplastic detection caused by disposable gloves. Environmental Science & Technology, 54(19), 12164-12172.

Yurtsever, M. (2019). Tiny, shiny, and colorful microplastics: Are regular glitters a significant source of microplastics?. Marine Pollution Bulletin, 146, 678-682.

The truth about microplastic. Podcast Recap.