Meet my microplastics

Thinking about the health risks of microplastics

18/09/2024

We already knew that islands of plastic float in our seas. Recently we discovered that plastic also flows into our bloodstream, as well as various organs in our bodies. [1] The effects on health, however, are far from clear. And even less clear is understanding how to deal with this uncertainty. I will try here to sketch out an answer.

The journey of microplastics

A recent OECD report [2] estimated that the world produced 353 million tons of plastic waste in 2019. Of this, about 79 million is abandoned, burned in the open, dumped at sea or in inadequate landfills.

Photo by FlyD on Unsplash

Due to weathering, plastic debris degrades by releasing microplastics, i.e., plastic particles less than 5 mm in diameter, and nanoplastics, particles less than 1 micron in diameter, into the environment. Microplastics and nanoplastics (MNPs) are also introduced into the environment by other factors, such as the abrasion of car tires or the abrasion of synthetic fabrics during machine washing [3].

MNPs thus pollute the planet’s ecosystems, obviously involving humans as well. MNPs enter the human body mainly through drinking water, food, air, and personal care products. For example, MNPs have been detected in fish and seafood, both wild and farmed [4].

MNPs then accumulate in our organs and tissues. So far, research has detected MNPs in the placenta, colon, faeces, liver, kidney, and blood [5].

The risks to human health

This sounds like a worrisome scenario, and it comes naturally to wonder about the risks of MNPs to human health. However, at this time the scientific evidence is still fragmented: the methods used are heterogeneous and quality control measures are often lacking [6]. As a 2022 WHO report argues, the available data cannot yet be used to assess the risks of MNPs to our health [7].

In April this year, an editorial in Nature [8] called on the scientific community to accelerate research on the topic, citing a recent pioneering study as an example [9].

This study recruited patients who were to undergo carotid endarterectomy. This procedure involves removing atherosclerotic plaques – that is, those deposits of lipids and other inflammatory cells that obstruct blood flow in the arteries – from the carotid artery. Analysing the plaques with an electron microscope, the presence of polyethylene was discovered in 58% of the patients. Through statistical analysis, the researchers inferred that patients in this subgroup had a higher risk of heart attack or stroke than other patients.

As the Nature editorial points out, however, this study does not prove a causal link between the presence of MNP and cardiovascular disease. Research still needs to answer many questions, such as studying the mechanisms that generate these correlations.

Staying with the trouble

While waiting for science to run its course, it is easy to indulge in apocalyptic narratives: the Human Being, defeated by himself, will drag the environment in which he lives with him into the abyss. Here I would like to try to change the perspective.

The irruption of MNPs into our organs should cause us to stop thinking of the Human Being as an individual in an environment, but rather as the environment itself. Just as the ocean shores, the organs of sardines [10] and the leaves of mangroves [11], our bodies are also an environment polluted by plastic.

This positioning of ours obliges us to “staying with the trouble“, to use the expression of ecofeminist philosopher Donna Haraway. Just following Haraway’s theories, [12] I would now like to weave the threads of a short multi-species fabulation. According to the philosopher, we should stop thinking of the human being as the main character of our epistemologies. Instead, the biotic and abiotic forces on the planet constitute the main story, of which the human being is only a part. Haraway believes that prosperity must be realised “as a multispecies response-ability” [13].

How could we import this philosophy into scientific practice? I believe Haraway would be a proponent of the “One Health” approach, a transdisciplinary perspective that animal, human, and environmental health are interdependent [14]. The One Health approach generates important research questions about the impact of MNPs [15]. For example, little is known about the effect of the most common agricultural practices on the concentration of MNPs in soil, the eventual desertification of which would compromise the food security of humans and animals. Addressing these problems involves specialists from different scientific disciplines, from medicine to agronomy and veterinary medicine.

Then, according to the One Health approach, dealing with human health involves also dealing with the health of the environment and animals and vice versa. Prosperity, then, is such only if it is multi-species.

Generate kinship with microplastics

A famous slogan of Haraway’s is “Make kin, not babies!” [16]. For Haraway, kinships are not just genealogical ties, but ties of care.

Inspired by Haraway, I propose to generate kinship through microplastics. The microplastic bond would replace the blood bond, generating assemblages of species united by a collective effort to care for each other. The One Health approach can be understood as the glue of this effort: only through caring for other species, united in misfortune by the microplastic bond, can we be truly healthy.

Dear sardines, dear mangroves, I present to you my microplastics. You present yours to me and we will thrive together.

References

[1] Ramsperger, A. F. R. M., Bergamaschi, E., Panizzolo, M., Fenoglio, I., Barbero, F., Peters, R., Undas, A., Purker, S., Giese, B., Lalyer, C. R., Tamargo, A., Moreno-Arribas, M. V., Grossart, H.-P., Kühnel, D., Dietrich, J., Paulsen, F., Afanou, A. K., Zienolddiny-Narui, S., Eriksen Hammer, S., … Laforsch, C. (2023). Nano- and microplastics: A comprehensive review on their exposure routes, translocation, and fate in humans. NanoImpact, 29, 100441. https://doi.org/10.1016/j.impact.2022.100441

[2] OECD (2022), Global Plastics Outlook: Policy Scenarios to 2060, OECD Publishing, Paris. https://doi.org/10.1787/aa1edf33-en.

[3] SAPEA, “A scientific perspective on microplastics in nature and society” (2019), pp. 24-25; https://doi.org/10.26356/microplastics.

[4] Ramsperger et al., op. cit., §3.

[5] Ivi, §5.

[6] Ibidem.

[7] Dietary and inhalation exposure to nano- and microplastic particles and potential implications for human health. Geneva: World Health Organization; 2022.

[8] Microplastics are everywhere—We need to understand how they affect human health. (2024). Nature Medicine, 30(4), 913–913. https://doi.org/10.1038/s41591-024-02968-x.

[9] Marfella, R., Prattichizzo, F., Sardu, C., Fulgenzi, G., Graciotti, L., Spadoni, T., D’Onofrio, N., Scisciola, L., La Grotta, R., Frigé, C., Pellegrini, V., Municinò, M., Siniscalchi, M., Spinetti, F., Vigliotti, G., Vecchione, C., Carrizzo, A., Accarino, G., Squillante, A., … Paolisso, G. (2024). Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. New England Journal of Medicine, 390(10), 900–910. https://doi.org/10.1056/NEJMoa2309822.

[10] Digka, N., Tsangaris, C., Torre, M., Anastasopoulou, A., & Zeri, C. (2018). Microplastics in mussels and fish from the Northern Ionian Sea. Marine Pollution Bulletin, 135, 30–40. https://doi.org/10.1016/j.marpolbul.2018.06.063.

[11] Huang, Y., Zhu, Z., Li, T., Li, M., Cai, Z., Wang, X., Gong, H., & Yan, M. (2024). Mangrove plants are promising bioindicator of coastal atmospheric microplastics pollution. Journal of Hazardous Materials, 465, 133473. https://doi.org/10.1016/j.jhazmat.2024.133473.

[12] Haraway, D. J. (2016). Staying with the trouble: Making kin in the Chthulucene, tr. it. Chthulucene: Sopravvivere su un pianeta infetto (C. Durastanti & C. Ciccioni, Trad.). Nero.

[13] Ivi, cap. 2.

[14] Cfr. anche Rock, M. J. (2017). Who or what is ‘the public’ in critical public health? Reflections on posthumanism and anthropological engagements with One Health. Critical Public Health, 27(3), 314–324. https://doi.org/10.1080/09581596.2017.1288287

[15] Prata, J. C., Da Costa, J. P., Lopes, I., Andrady, A. L., Duarte, A. C., & Rocha-Santos, T. (2021). A One Health perspective of the impacts of microplastics on animal, human and environmental health. Science of The Total Environment, 777, 146094. https://doi.org/10.1016/j.scitotenv.2021.146094.

[16] Haraway, op. cit., cap. 4

Filippo Vasone

He holds a Master’s degree in Logic and Philosophy of Science (LMU – Munich), during which he worked on the relationship between science and society. He currently studies Data Analysis (UniTo) and writes about philosophy, science and values online