Nanoplastics are Entering Our Bodies
Erica Cirino
[This is an excerpt from ‘Thicker Than Water: The Quest for Solutions to the Plastic Crisis’, by Erica Cirino (Island Press, 2021).]
The air is plasticized, and we are no better protected from it outdoors than indoors. Minuscule plastic fibers, fragments, foam, and films are shed from plastic stuff and are perpetually floating into and free-falling down on us from the atmosphere. Rain flushes micro- and nanoplastics out of the sky back to Earth. Plastic-filled snow is accumulating in urban areas like Bremen, Germany, and remote regions like the Arctic and Swiss Alps.
Wind and storms carry particles shed from plastic items and debris through the air for dozens, even hundreds, of miles before depositing them back on Earth. Dongguan, Paris, London, and other metropolises around the world are enveloped in air that is perpetually permeated by tiny plastic particles small enough to lodge themselves in human lungs.
Toxic Tires
Urban regions are especially full of what scientists believe is one of the most hazardous particulate pollution varieties: synthetic tires’ debris. As a result of the normal friction caused by brake pads and asphalt roads, and of weathering and wear, these tires shed plastic fragments, metals, and other toxic materials. Like the plastic used to manufacture consumer items and packaging, synthetic tires contain a manufacturer’s proprietary blend of poisons meant to improve a plastic product’s appearance and performance.
Tire particles from the billions of cars, trucks, bikes, tractors, and other vehicles moving across the world escape into air, soil, and water bodies. Scientists are just beginning to understand the grave danger: In 2020, researchers in Washington State determined that the presence of 6PPD-quinone, a byproduct of rubber-stabilizing chemical 6PPD, was playing a major factor in a mysterious long-term die-off of coho salmon in the U.S. Pacific Northwest. When Washington’s fall rains heralded spawning salmon’s return from sea to stream, the precipitation also washed car tire fragments and other plastic particles into these freshwater ecosystems.
Up to 90 percent of all coho salmon returning to spawn in this region have died—much greater than is considered natural. As the study’s lead author, environmental chemist Zhenyu Tian, explained in a 2020 interview with Oregon Public Broadcasting, 6PPD-quinone appears to be a key culprit: “You put this chemical, this transformation product, into a fish tank, and coho die… really fast.”
Microplastic Inside Human Airways
While other researchers had previously searched for, and detected, microplastic dispersed in indoor and outdoor air, Alvise Vianello, an Italian scientist and associate professor at Aalborg University in Denmark, was the first to do so using a mannequin emulating human breathing via a mechanical lung system, publishing his study’s results in 2019. (Despite the evidence his research provides—that plastic is getting inside of human bodies and could be harming us—it was not until 2022 that modern health researchers first confirmed the presence of microplastics in human lungs. And as comprehensive health research has ramped up, we are just beginning to understand how having plastic particles around us and in us at all times might be affecting human health.)
Vianello and his colleague Jes Vollertsen, a professor of environmental studies at Aalborg University, explained that they’ve brought their findings to researchers at their university’s hospital for future collaborative research, perhaps searching for plastic inside human cadavers. “We now have enough evidence that we should start looking for microplastic inside human airways,” Vollertsen said. “Until then, it’s unclear whether or not we should be worried that we are breathing in plastic.”
When I met Vollertsen in 2019, he had speculated that some of the microplastic we breathe in could be expelled when we exhale. Yet even if that’s true, our lungs are indeed holding onto some of the plastic that enters, potentially resulting in damage.
Other researchers, like Joana Correia Prata, DVM, PhD, who studied microplastics at the University of Aveiro in Portugal, have highlighted the need for systematic research on the human health effects of breathing in microplastic. “[Microplastic] particles and fibers, depending on their density, size, and shape, can reach the deep lung causing chronic inflammation,” she said. Prata noted that people working in environments with high levels of airborne microplastics, such as those employed in the textile industry, often suffer respiratory problems. The perpetual presence of a comparatively lower amount of microplastics in our homes has not yet been linked to specific ailments.
While they’ve dissected the bodies of countless nonhuman animals since the 1970s, scientists only began exploring human tissues for signs of nano- and microplastic in earnest during the late 2010s and early 2020s. This, despite strong evidence suggesting plastic particles—and the toxins that adhere to them—permeate our environment and are widespread in our diets. From 2010 to 2020, scientists have detected microplastic in the bodies of fish and shellfish; in packaged meats, processed foods, beer, sea salt, soft drinks, tap water, and bottled water. There are tiny plastic particles embedded in conventionally grown fruits and vegetables sold in supermarkets and food stalls.
Petrochemical-Based Plastics, Fertilizers, and Pesticides
As the world rapidly ramped up its production of plastic in the 1950s and ’60s, two other booms occurred simultaneously: that of the world’s human population and the continued development of industrial agriculture. The latter would feed the former and was made possible thanks to the development of petrochemical-based plastics, fertilizers, and pesticides.
By the late 1950s, farmers struggling to keep up with feeding the world’s growing population welcomed new research papers and bulletins published by agricultural scientists extolling the benefits of using plastic, specifically dark-colored, low-density polyethylene sheets, to boost the yields of growing crops.
Scientists laid out step-by-step instructions on how the plastic sheets should be rolled out over crops to retain water, reducing the need for irrigation, and to control weeds and insects, which couldn’t as easily penetrate plastic-wrapped soil.
This “plasticulture” has become a standard farming practice, transforming the soils humans have long sown from something familiar to something unknown. Crops grown with plastic seem to offer higher yields in the short term, while in the long term, use of plastic in agriculture could create toxic soils that repel water instead of absorbing it, a potentially catastrophic problem. This presence of plastic particles in the soil causes increased erosion and dust—as well as the dissolution of ancient symbiotic relationships between soil microbes, insects, and fungi that help keep plants—and our planet—alive.
From the polluted soils we’ve created, plants pull in tiny nanoplastic particles through their roots along with the water they need to survive, with serious consequences: An accumulation of nanoplastic particles in a plant’s roots diminishes its ability to absorb water, impairing growth and development. Scientists have also found evidence that nanoplastic may alter a plant’s genetic makeup in a manner increasing its disease susceptibility.
Plastic: Part of the Human Diet
Based on the levels of micro- and nanoplastics detected in human diets, it’s estimated that most people unwittingly ingest anywhere from 39,000 to 52,000 bits of microplastic in their diets each year. That number increases by 90,000 microplastic particles for people who regularly consume bottled water, and by 4,000 particles for those who drink water from municipal taps.
In 2018, scientists in Austria detected microplastic in human stool samples collected from eight volunteers from eight different countries across Europe and Asia. By 2023, scientists had detected the presence of plastic particles in people’s lungs, bloodstreams, veins, placentas, feces, testes/semen, and breast milk. And while the long-term health impacts of plastic on the human body are still unknown, it is well understood that plastic has toxic effects on laboratory animals, marine wildlife, and human cell lines.
In a 2022 study, researchers showed that nanoplastics less than 100 nanometers wide can enter the blood and organs of animals and cause inflammation, toxicity, and changes in neurological function.
Clearly, micro- and nanoplastics are getting into us, with at least some escaping through our digestive tracts. We seem to be drinking, eating, and breathing it in.
And these tiny particles are just one component of plastic’s myriad forms of pollution. From the moment plastic’s fossil fuel ingredients are extracted, to its production, transportation, use, and eventual disposal in landfills, incinerators, and the environment, the plastics pipeline emits toxic chemicals that pollute Earth’s air, soils, waters, seas, animals, plants, and human bodies, and releases greenhouse gases that drive the climate crisis. Most often harmed are already underserved groups, including Black, Brown, Indigenous, rural, poor, and fenceline communities everywhere, driving severe injustice worldwide.
(Erica Cirino is a contributor to the Observatory and a science writer and artist who explores the intersection of the human and nonhuman worlds. She took on the role of communications manager. Excerpt courtesy: Earth | Food | Life, a project of the Independent Media Institute, a nonprofit organization that educates the public through a diverse array of independent media projects and programs.)
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The Impact of Plastic on Human Health
Robin Scher
In 2019, the European Commission’s Scientific Committee on Health, Environmental and Emerging Risks published a statement that identified 14 emerging health and environmental issues. Right near the top of that list was plastic waste. The committee emphasized the “urgent” need “for a better assessment of hazard and risk” associated with exposure to plastics of different shapes and forms.
The Facts About Plastic
During World War II, U.S. plastic production increased by 300 percent. Since then, plastic has become ever more ubiquitous, and by 2014, according to market research firm PlasticsEurope, had surpassed 300 million tons produced per year. There’s a good reason for that. The wondrous nature of plastic is that it’s lightweight, highly malleable, and resistant to biodegradation. It is widely understood that this last property is the root of what has emerged as one of the most intractable environmental problems as the plastic waste piles up around the globe. What is less understood are the exact reasons why.
Plastic is made up almost entirely of hydrocarbon chains, which are an incredibly stable type of molecular bond. In cases where hydrocarbon chains occur naturally, that stability is a necessary component of an organism’s function and generally forms part of a greater ecosystem. Plastics, however, are synthetic, which means they’re no good as a food source for microorganisms (with at least one rare exception) and, as we’ve so tragically come to learn, that is a major problem.
On one hand, there’s the obvious issue of what happens to all that accumulated plastic trash. We all know the answer to that one: It turns into giant islands of floating trash, it goes up into poor turtles’ nostrils, and is found in the stomachs of beached whales. According to a 2022 study published in the online journal Nature Communications, blue whales could be ingesting as much as 10 million pieces of microplastic every day. According to the World Wide Fund for Nature’s Living Earth 2018 report, 90 percent of the world’s seabirds have plastic in their stomachs, a figure that is expected to rise to 99 percent by 2050.
Marauding Microplastics
Over the course of several decades, as plastic is exposed to the elements, it begins to decompose into smaller particles. While this process, known as photooxidation, does not affect plastic on a molecular level, it does eventually break it down to its nanoparticles. If you’re finding that hard to imagine, picture a grocery bag that’s been zapped by a shrink ray: It’s the exact same piece of plastic, only now it’s microscopic.
On the surface, this result may appear to be a good thing. Out of sight, out of mind, right? If only it were that simple. Plastic may actually be at its most threatening once it has broken down to the point it’s invisible to the naked eye because at that point, those little particles can travel a lot faster and further, and into the bodies of animals, including us.
Research conducted by the State University of New York at Fredonia found a significant amount of microplastics in bottled water. To be precise, 10.4 microplastic particles per one liter of water were recorded in a sample of 259 bottles representing 11 major brands across nine countries, including Aquafina, Dasani, Evian, Nestlé Pure Life and San Pellegrino, reflecting twice the amount of plastic found in a previous study using tap water. Researchers suggested the plastic contamination could have partially come from the bottling process.
Avoiding bottled water and sticking to municipal water won’t necessarily solve the problem of ingesting microplastics from drinking water.
“Substantial amounts of microplastics” were recently found in tap water and rivers throughout South Africa, according to a recent study conducted by scientists from North-West University. Zoologist Henk Bouwman, a member of the research team, explained that the findings were conclusive, but the implications remain unclear. “There is no consensus yet on any health impacts as the science is still in its infancy,” he told Johannesburg’s Daily Maverick. “It might be benign, and it might not be. There are a whole lot of things we don’t understand at this stage.”
This topic was further explored by National Geographic in a 2018 article. For the piece, Chelsea Rochman, an ecologist at the University of Toronto, shared her research that found that fish suffered liver damage from ingesting polythene plastic (the kind plastic bags are made of), while oysters exposed to polystyrene tended to produce fewer eggs and less mobile sperm. But this does not necessarily mean humans will suffer the same effects.
Plastics and Human Health
Given the ubiquitousness of microplastics, it’s no surprise that they have infiltrated our bodies too. A breakthrough study published in 2022, using blood donated by members of the general public, found the tiny particles in 80 percent of the samples. A 2023 UK study found that microplastics can pass through blood vessels to vascular tissue, potentially contributing to damage inside the vein. Other studies have shown that they are present in our feces, our lungs, our stomachs and, most worryingly, in placentas.
It is not yet clear what effect this infiltration has on human health.
As the National Geographic article’s author Elizabeth Royte points out, it’s difficult to study the impact of microplastics on human health for a number of reasons. First, there’s the simple fact that “people can’t be asked to eat plastics for experiments.” Extrapolating the findings from fish experiments doesn’t work either, as “plastics and their additives act differently depending on physical and chemical contexts,” as well as the fact that “their characteristics may change as creatures along the food chain consume, metabolize or excrete them.” As a result, notes Royte, “we know virtually nothing about how food processing or cooking affects the toxicity of plastics in aquatic organisms or what level of contamination might hurt us.”
For Rochman, there is no doubt that “there are effects from plastics on animals at nearly all levels of biological organization.” Studies show that in fish, microplastic pollution (MP) causes structural damage and affects metabolic balance, behavior and fertility. In laboratory mice and rats it causes similar biochemical and structure damage.
OK, so we may not have clear evidence on the direct health impacts of microplastics where human beings are concerned, but what about more immediate side effects?
For one, there’s the fact that microplastics are foreign particles entering our bodies. Inflammation, for instance, is a response triggered by the immune system to this sort of invasion, writes Rachel Adams, a senior lecturer in biomedical science at Cardiff Metropolitan University, in The Conversation. Another cause for concern is that these microparticles act as carriers for other toxins entering the body. Toxic metals like mercury and organic pollutants like pesticides are just two examples of hazardous materials that could enter the body attached to plastic particles. They can slowly accumulate over time in our fatty tissue.
Quantifying Harm
“We do not currently have clear evidence that plastic microparticles in drinking water have a negative effect on health,” writes Adams. “But given the effects other particles can have, we urgently need to find out more about plastic microparticles in the body.”
John Meeker, professor of environmental health sciences and global public health at the University of Michigan, concurs. “We first need to figure out how best to measure exposure then document whether people are being exposed, and, if so, how much,” wrote Meeker over email. In order to do this, he continued, scientists need to determine what environmental factors influence exposure levels and “what aspects of microplastics could be most relevant to toxicity—is it size, shape, chemical makeup or additives used in the plastics, or even toxins picked up by the plastic from its surrounding environment?” Once these factors have been established, we can begin to consider how the body processes these plastics, and what effects the various levels of exposure can have on humans over a period of time.
“Once we have found ways to measure exposure in humans, we will then need to conduct cohort studies in various types of populations to look for associations between exposure and various health endpoints,” said Meeker, advising that “these should be done in concert with experimental laboratory studies on toxicity to establish estimates about health risk.” Some efforts have begun in this direction. For example, in 2022 California became the first state in the USA to adopt a state-wide microplastics strategy. Among other actions, the state requires monitoring of microplastics in drinking water and investigate whether it should set a limit on the particles in this water to protect public health.
For the gamblers out there, this lack of scientific certainty at present might seem like an invitation to continue rolling the plastic dice. The potential hazards of microplastic, however, are far from the only cause for concern.
Bothersome BPA and Problematic Phthalates
Modern living has made it so that there’s no escaping contact with plastic—and the various extra chemicals it contains. Take Bisphenol A (BPA), which gives plastic its shape and structure, and the phthalates that make plastic soft and flexible. We end up ingesting a fair amount of these chemicals when plastic comes into contact with our food or even our skin. In turn, this affects our hormone levels, which is why, for the most part, chemicals such as BPA are heavily regulated. There is a growing body of research showing that exposure to industrial chemicals commonly found in plastics may help contribute to metabolic disorders like obesity and diabetes.
Added to this is the concerning fact that an increasing number of these chemicals are being detected in humans. A recent study conducted by the University of Exeter found traces of BPA in over 80 percent of teenagers. Reporting on the study, The Guardian explained how BPA mimics estrogen, and in so doing disrupts the endocrine system, which is responsible for regulating metabolism, growth, sexual function and sleep. But as is the case with microplastics, it is difficult to draw conclusive causal links between BPA and these health impacts due to ethical concerns around testing on humans.
Despite this lack of certainty, there’s enough cause for concern that governments have responded to this plastic plight. Legislation has been passed in Australia, Canada, the European Union and the United States restricting or prohibiting the use of phthalates in certain consumer products. According to a paper published by the Indian Journal of Occupational and Environmental Medicine, these moves respond to the “variety of adverse outcomes” caused by the chemical, “including increased adiposity and insulin resistance” as well as “decreased levels of sex hormones, and other consequences for the human reproductive system.”
While it’s important to understand the health impact of plastic, perhaps a more pressing question is what happens when we tell ourselves that plastic is safe—and continue to produce it in ever greater quantities. According to Statista, a market research firm, global plastic production has grown from 50 to 335 million metric tons over the past four decades. Chances are likely that the ultimate consequence of our plastic consumption will be something far greater, and perhaps direr, than our current scientific understanding is able to predict.
(Robin Scher is a contributor to the Observatory and freelance writer based in Johannesburg, South Africa. Courtesy: Truthout, a US nonprofit news organization dedicated to providing independent reporting and commentary on a diverse range of social justice issues.)
