Degrading plastics turn into “microplastics.”
Plastics are all around us, from the polyester clothes we wear and the packaging that contains our food to construction materials in our homes and more.
Tiny pieces of these plastics have even made their way into our food chain.
Now two reports have put a spotlight on how much plastic we’re ingesting via foods and drinks.
A report published this week by the World Wildlife Fund from research done by the University of Newcastle, Australia, looked at data from 52 studies on microplastic ingestion.
Researchers found that people are at risk for ingesting around 5 grams of plastic per week. That’s equivalent to a credit card.
And earlier this month, in the newest issue of the journal Environmental Science and Technology, researchers reported that Americans consume an estimated 39,000 to 52,000 microplastic particles per year from seafood, water, sugars, salts, and alcohol alone.
People who rely on bottled water might be ingesting 90,000 more microplastic particles per year on average than those who drink only tap water, the authors warn.
“If you’re concerned about consuming plastic in beverages, then you’d be wise to avoid bottled water,” Mary Kosuth, MS, an assistant professor at Dunwoody College of Technology in Minneapolis who has studied microplastic contamination, told Healthline.
But that strategy alone is unlikely to stop microplastic particles from entering our bodies due to the ubiquity of plastics in our homes and wider environments.
“Even if you had a reverse-osmosis system in your house and you’re drinking super clean water, leaving your cup on the countertop leaves it vulnerable to plastics that are coming off of your clothing,” Kosuth said.
“We’d like to think that we as individuals can just make choices in our own lives to help protect us from these exposures, but sometimes we have to work together to encourage industry to give us alternatives [to plastic products],” she added.
To assess microplastic consumption, the authors of the Environmental Science and Technology report conducted a review of peer-reviewed research on the concentration of microplastics in food items.
They found 26 studies that assessed various sources of seafood, bottled water, tap water, sugars, salts, and alcohol.
Other food groups weren’t included in the analysis due to the lack of published research on microplastics in those foods.
Given the exclusion of many foods, the authors suggest that for most people, the actual amount of microplastics consumed each year is likely higher than what they’ve reported.
“Our estimates of American consumption of microplastics are likely drastic underestimates overall,” the authors wrote.
“If our findings are remotely representative, annual microplastic consumption could exceed several hundred thousand [particles],” they added.
These studies contribute to a growing body of evidence on microplastic exposure.
For a previous study, researchers from the Medical University of Vienna and the Environment Agency Austria tested stool samples from people in eight countries around the world. They found microplastic particles in every sample.
When they presented their findings at the 26th United European Gastroenterology Week in Vienna last year, they reported finding 20 microplastic particles in every 10 grams of stool.
Those findings don’t surprise Rolf Halden, PhD, PE, director of the Center for Environmental Health Engineering at the Biodesign Institute at Arizona State University.
“It would be naïve to think that the plastics that are present in our clothing, on our skin, and in our work and living spaces would not also enter our bodies,” Halden told Healthline in a 2018 interview.
“What surprises me more is how long it’s taken until we’ve developed an interest in looking into this exposure,” he added.
Microplastics are small pieces of plastic that measure less than 5 millimeters long.
They’re intentionally added to some consumer products, including certain types of household cleaners and cosmetics that contain plastic microbeads as exfoliants.
Microplastics are also unintentionally created when larger pieces of plastic break down.
These tiny bits of plastic accumulate in the dust in our homes, workplaces, and wider environments.
They can also enter our food chain, not only through the manufacturing methods used to process foods, but also through the bodies of animals we eat.
Although plastic products have been a pervasive part of modern life for more than half a century, the science of plastic exposure is still young.
“We have probably been immersed in microplastics and nanoplastics for a long time, and we’re finally trying to understand, what are the implications,” Halden said.
Although more research is needed to understand the potential effects of microplastic exposure, studies suggest that chemicals in many plastic products might be harmful to human health.
For example, the basic building blocks of some types of plastic have known toxic effects.
Bisphenol A (BPA), for instance, is used to produce certain types of polycarbonate. It’s a type of tough and transparent plastic.
BPA is a controversial endocrine-disrupting chemical that may interfere with natural hormone activity in humans.
The Food and Drug Administration has declared that for most people, their exposure to BPA is at safe levels.
According to the Environmental Protection Agency, standardized toxicity tests have found quantities of BPA in humans below levels of potential concern.
But some research in animals and humans suggests BPA exposure may raise the risk of birth defects, metabolic disease, and other health problems, warns a review published in Reproductive Toxicology.
Recent studies in animals have found that even low doses of BPA might have negative effects. These studies have yet to be replicated in humans.
Even in cases when the basic building blocks of plastics themselves pose little to no risk to human health, potentially harmful chemicals are often added to plastics to modify their appearance or functionality.
For example, phthalates are endocrine-disrupting chemicals often used as “plasticizers” to make plastics more flexible.
Among other health effects, phthalate exposure has been linked to reduced testosterone levels in male fetuses.
“Phthalate syndrome is something that is found in males who are exposed to phthalates in utero,” Shanna Swan, PhD, a professor of environmental and public health at the Icahn School of Medicine at Mount Sinai in New York, told Healthline in an interview last year.
“And what happens is that the development of the male genitals is incompletely masculinized,” she said.
For example, her research suggests that male fetuses with higher levels of phthalate exposure are more likely to be born with testicles that haven’t fully descended and small penises.
They also tend to have a shorter than average distance between their anus and genitals. This has been linked to increased risk of infertility later in life.
In addition to phthalates, other chemicals are often added to plastics — many of which have been linked to potential health effects.
For example, coloring agents often contain heavy metals or other toxic ingredients. Flame-retardants can have endocrine-disrupting effects. So can the antimicrobial agents added to some plastics, Halden says.
Microplastic particles can also pick up other pollutants from the environment around them.
“When the plastics are in the environment for a long time, they take up contaminants from the air, from the water, and from the soil,” Halden said.
“We call them ‘toxic rafts,’ so it doesn’t really matter what the makeup of the plastic is, but if it has a tendency to attract environmental pollutants and store them and concentrate them, then obviously we are concerned about contact with such material,” he said.
More research is needed to understand the potential health effects of exposure to not only microplastics, but also nanoplastics, Halden says.
Nanoplastics measure up to 1 to 100 micrometers in length.
At that size, they can potentially enter the human bloodstream and cells.
Scientists are just beginning to explore the effects that nanoplastic exposure might have on the human body.
In the meantime, Halden would like to see changes in how plastics are made and used.
“Why wait until we have nailed down the last scientific fact? There are many reasons to reconsider and change the ways that we work with plastics today,” he said.
For example, he would like manufacturers to use less toxic and less environmentally destructive alternatives to the fossil fuels that most plastics are currently made from.
He’d also like manufacturers to develop and use plastics that have a shorter life span so they don’t persist for millennia in our environments.
Government policymakers have an important role to play in regulating the industry and promoting these changes, but Halden believes that consumers can also help.
“It’s up to the consumer to indicate and signal that they don’t want this. They just shouldn’t buy it. They should fight for alternatives. They should ask, what is this material in my stuff? Is it safe?” he said.
“If we do that, we might create the political will to give us the next generation of plastics, which is urgently needed,” he added.
Researchers have found that microplastic particles are present in many common foods as well as human stool samples.
Scientists are working to understand the potential health effects of microplastics exposure, including the effects that chemicals like BPA and phthalates might have on our bodies.
This article has been updated from an earlier version that was published in November 2018 to include new research on microplastic exposure.