Microplastics and Health: An Invisible Threat
In 2019, the World Health Organization (WHO) urged governments and the relevant authorities to carry out further investigation on the relationship between microplastics and health. Microplastics are small pieces of plastic that pollute the environment. At present they are considered a public health problem, in principle due to the damage to ecosystems and their impact on human health.
Microplastics are everywhere: on the seabed, in fish and shellfish, in drinking water, in beer, in the rain, and in plastic containers (especially when exposed to warm or hot water). Microplastics have even been found in the Arctic, so it doesn’t seem possible to get away from them. With this in mind, are they really a health threat?
Microplastics and health
It was Richard Thompson who, in 2004, coined the term microplastics. At first, people thought they were only found on the coast, but then experts began to find them practically anywhere they looked.
Research regarding microplastics and health suggested that almost all personal care products released them, but these days we know that every day most people eat or inhale them in some way.
Indeed, and as the experts point out, there are three main channels through which they are assimilated: ingestion, inhalation, and skin contact.
A study published in 2021 in Environmental Science & Technology suggested that the average person may consume, inhale, or assimilate the equivalent of a credit card per year. Exposure is self-evident, and, up to a point, not much can be done to prevent it.
Microplastics don’t go unnoticed in the animal environment either. So far, experts have shown they cause reproductive toxicity in oysters, liver toxicity in zebrafish, and that they promote tissue bioaccumulation and organ toxicity in mice.
With all this as a preamble, we can see that microplastics are a threat to human health, but in what way and how harmful are they?
There’s still no full answer to this question, partly because the investigation of this relationship is in full swing. Studies so far indicate that the impact may not go unnoticed. We’ll now mention some ways and channels through which microplastics can affect health according to experts.
Microplastics and nanoplastics in the balanced diet
Human beings ingest microplastics and nanoplastics through their regular diet. These are found in significant proportions in fish, shrimp, oysters, clams, shellfish, mussels, and others.
Contamination can also occur during the production and packaging process, so they’re also in honey, beer, sugar, and salt (among other things).
They’re also in all water sources (without exception). A study published in 2018 in PLOS ONE found that 81% of 159 global sources of tap water have microplastics smaller than 5 millimeters.
That same year, research published in Frontiers in Chemistry analyzed 259 processed water brands. They found microplastics in approximately 93% of them.
In short, one way or another, microplastics enter a person’s diet. This is without considering those that enter due to the interaction of food with plastic containers, glasses, plates, and others.
It’s thought that these can penetrate lymphatic tissue, and it’s likely that they enter by phagocytosis or endocytosis and infiltrate the microfold (M) cells in Peyer’s patches. Despite this, there are no current studies that determine the degree of absorption or its impact.
Microplastics and nanoplastics in lung exposure
Exposure to microplastics and nanoplastics occurs both indoors and outdoors. Indoors it’s likely to be mainly airborne synthetic textiles, while outdoors it’s due to contaminated aerosol debris or airborne fertilizer particles from wastewater treatments.
For example, researchers have found that their interaction can lead to chemical toxicity and the introduction of pathogen and parasite vectors into the body via the lungs.
In animals, inhalation has been associated with an increased risk of developing lung cancer and inflammation. Exposure is higher in urban areas than in suburban ones, due to the levels of pollution associated with them.
Microplastics and nanoplastics in dermal exposure
Body scrubs and face creams are other means by which microplastics enter the body. They can also do so through interaction with water contaminated with microplastics, especially via sweat glands, skin wounds, and hair follicles.
Its actual impact isn’t known, but some experts indicate that the nanoparticles are taken up by Langerhans cells.
The different layers of the skin offer protection against these, but the truth is that beauty products contain properties that make it easier for their compounds to enter the skin.
Creams, scrubs, and other products that haven’t gone through strict safety and hygiene standards during their manufacture contain a higher number of microplastics and nanoplastics.
Final thoughts on microplastics and health
These are the latest discoveries that scientists have made in their research. We reiterate that the real impact of microplastics on human health still isn’t very well known. The fact that we’re exposed to considerable amounts isn’t in doubt, but exactly how they affect our health is.
However, international organizations are implementing agendas and programs to reduce the amounts that are produced and deposited in the environment. During the next few decades, we will obtain greater knowledge about the impact they have on our health, and more strategies will be developed to minimize this impact. The first step has already been taken, and the relationship between microplastics and health is firmly in the public eye.
- Deng Y, Zhang Y, Lemos B, Ren H. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure. Sci Rep. 2017 Apr 24;7:46687.
- Jiang B, Kauffman AE, Li L, et al. Impactos en la salud de la contaminación ambiental de micro y nanoplásticos: una revisión. Medio Ambiente Salud Prev Med. 2020;25(1):29. Publicado el 14 de julio de 2020.
- Kosuth M, Mason SA, Wattenberg EV. Anthropogenic contamination of tap water, beer, and sea salt. PLoS One. 2018 Apr 11;13(4):e0194970.
- Lu Y, Zhang Y, Deng Y, Jiang W, Zhao Y, Geng J, Ding L, Ren H. Uptake and Accumulation of Polystyrene Microplastics in Zebrafish (Danio rerio) and Toxic Effects in Liver. Environ Sci Technol. 2016 Apr 5;50(7):4054-60.
- Mason SA, Welch VG, Neratko J. Synthetic Polymer Contamination in Bottled Water. Front Chem. 2018 Sep 11;6:407.
- Mohamed Nor NH, Kooi M, Diepens NJ, Koelmans AA. Lifetime Accumulation of Microplastic in Children and Adults. Environ Sci Technol. 2021 Apr 20;55(8):5084-5096.
- Ohlwein S, Kappeler R, Kutlar Joss M, Künzli N, Hoffmann B. Health effects of ultrafine particles: a systematic literature review update of epidemiological evidence. Int J Public Health. 2019 May;64(4):547-559.
- Prata JC. Airborne microplastics: Consequences to human health? Environ Pollut. 2018 Mar;234:115-126.
- Thompson, R. C., Olsen, Y., Mitchell, R. P., Davis, A., Rowland, S. J., John, A. W., … & Russell, A. E. Lost at sea: where is all the plastic?. Science. 2004; 304(5672): 838-838.
- Rahman, A., Sarkar, A., Yadav, O. P., Achari, G., & Slobodnik, J. Potential human health risks due to environmental exposure to nano-and microplastics and knowledge gaps: A scoping review. Science of the Total Environment. 2021; 757: 143872.
- Sussarellu R, Suquet M, Thomas Y, Lambert C, Fabioux C, Pernet ME, Le Goïc N, Quillien V, Mingant C, Epelboin Y, Corporeau C, Guyomarch J, Robbens J, Paul-Pont I, Soudant P, Huvet A. Oyster reproduction is affected by exposure to polystyrene microplastics. Proc Natl Acad Sci U S A. 2016 Mar 1;113(9):2430-5.
- Vogt A, Combadiere B, Hadam S, Stieler KM, Lademann J, Schaefer H, Autran B, Sterry W, Blume-Peytavi U. 40 nm, but not 750 or 1,500 nm, nanoparticles enter epidermal CD1a+ cells after transcutaneous application on human skin. J Invest Dermatol. 2006 Jun;126(6):1316-22.