Are Microplastics Harmful?

gloved hands holding microplastics

The Bottom Line

Microplastics are common throughout our environment and are present in air, food, and drinking water. Microplastics have also been found in the human body, but it’s unclear if they cause undesirable health effects.

young woman using a net to clean microplastics from the ocean

The Full Story

What are microplastics and where do they come from?

If you take a look at your current surroundings, it’s likely that you will see plastic. The production and use of plastic products has increased dramatically since the widespread manufacturing of plastics began in the 1950’s. Plastics are lightweight, durable, and cheap, and these characteristics make them a useful component of our housewares, packaging materials, and other everyday goods. Currently, more than 320 million tons of plastic are produced worldwide each year. Nearly half of these products are manufactured for single-use packaging. Since only a small fraction of plastic products are recycled, many plastic products are discarded as waste.

Plastics are made from petroleum derivatives that are not easily biodegradable. This means that instead of breaking down naturally, discarded plastic products accumulate and persist in landfills, oceans, and other environments. Plastics are found in all the oceans on Earth. Marine mammals and bird species are known to consume plastic fragments, and some bird species even feed plastic pieces to their chicks.As many as 50 trillion pieces of plastic may be present in oceans today, and 5 million tons of plastic pieces are carried from rivers to oceans each year. When plastic products enter marine environments, they are subjected to UV radiation, winds, and physical abrasion from wave currents. These forces promote the breakdown of plastic products into smaller fragments. These fragments may be called “microplastics” or “nanoplastics”, depending on their size. In general, microplastics are plastic fragments that measure less than 5 millimeters in length, while nanoplastics are smaller pieces that measure less than 1 micron in length.

 

Why are microplastics a problem?

Because of their small size, microplastics can easily spread through the air and accumulate in the environment and may be difficult to detect. Microplastics are present in alcohol, drinking water (bottled water contains more microplastics than tap water), and even table salt. Filter feeders such as mussels and oysters can consume microplastics that are suspended in seawater, and microplastics are found in many seafood species. Microplastics have also been intentionally manufactured for use in exfoliants, toothpastes, and other cosmetic products. In the United States, Congress passed the Microbead-Free Waters Act of 2015, which prohibited the manufacture and sale of rinse-off cosmetics (including toothpastes, cleanses, and exfoliators) that contain microplastics.

 

Do microplastics harm humans?

When humans consume food, drink water, or breathe air that is contaminated with microplastics, the plastic fragments can enter the body. Overall, food intake results in the consumption of up to 52,000 microplastic fragments per person each year. Microplastics have been found in human saliva, head hair, and feces, suggesting that we are all likely exposed to these plastic fragments on a regular basis. Some researchers believe that microplastics may have detrimental effects on human health. Microplastics can absorb unwanted and undesirable chemicals including heavy metals, polychlorinated biphenyls (PCB’s), and pesticides. Human consumption of microplastics can result in an increased exposure to these chemicals and might lead to poisonous effects. Humans can also be exposed to microplastics through inhalation of contaminated fibers or dust, and microplastics have been found in human lung tissue. Microplastics may also enter the skin through sweat glands, hair follicles, or open wounds. While some studies suggest that microplastics may affect inflammation, cellular survival, and metabolism in humans, the true health risks of microplastics remain poorly understood. Even though microplastics are known to enter the human body, scientists still don’t know how or if the body absorbs, metabolizes, or eliminates these particles, and the exact dose of microplastics needed to cause disease remains unknown. Many of the studies that assessed potential health exposures of microplastics involved occupational settings (where workers were exposed to high amounts of certain types of microplastics, often for prolonged periods of time) or implanted plastic medical devices, and the results of these studies may not be applicable to the general population. Since plastics are a relatively new invention in our society and have only been in widespread use since the 1950’s, there are few long-term studies of the effects of microplastics on the human body. Because of these factors, it is difficult to state with certainty that microplastics are harmful to human health.

Because microplastics are so common throughout our environment, it’s likely impossible to avoid all contact with these particles. There are currently no regulatory exposure limits for microplastics or nanoplastics. People who desire to avoid exposure to microplastics may consider using water filtration systems to remove microplastics from drinking water, although this does not prevent exposure to other sources of microplastic fragments such as food or air. Use of paper, bamboo, or other alternatives to plastic may also reduce the amount of microplastics that eventually enter the environment and our bodies. For now, there is no conclusive evidence that microplastics cause cancer or other serious diseases in humans.

If you have questions about poisoning from environmental sources, contact Poison Control for expert advice. There are two ways to contact Poison Control in the United States: online at www.poison.org or by phone at 1-800-222-1222. Both options are free, confidential, and available 24 hours a day.


Kelly Johnson-Arbor, MD
Medical Toxicologist

Poisoned?

Call 1-800-222-1222 or

HELP ME online

Prevention Tips

  • Avoid use of single-use plastic products such as takeout food containers and disposable utensils.
  • Use biodegradable materials to reduce environmental waste.
  • Consider using a water filter to eliminate contaminants from drinking water.

This Really Happened

Eight healthy men and women (age range 33-65 years) participated in a study to assess the presence of microplastics in the human body. Seven of the study participants admitted to drinking from plastic bottles daily, and several had used cosmetic products that contained plastic polymers. Each participant provided a stool sample which was then assessed for the presence of microplastics. Three to seven microplastics of various sizes and shapes were detected in each stool sample, suggesting that ingestion of microplastics is common in humans.

For More Information

The Microbead-Free Waters Act: FAQs (U.S. Food & Drug Administration)

Microplastics in the human body: What we know and don't know (NBC News)


References

Andrady AL. Microplastics in the marine environment. Mar Pollut Bull. 2011 Aug;62(8):1596-605.

Brachner A, Fragouli D, Duarte IF, Farias PMA, Dembski S, Ghosh M, Barisic I, Zdzieblo D, Vanoirbeek J, Schwabl P, Neuhaus W. Assessment of Human Health Risks Posed by Nano-and Microplastics Is Currently Not Feasible. Int J Environ Res Public Health. 2020 Nov 27;17(23):8832.

Cox KD, Covernton GA, Davies HL, Dower JF, Juanes F, Dudas SE. Human Consumption of Microplastics. Environ Sci Technol. 2019 Jun 18;53(12):7068-7074.

De-la-Torre GE. Microplastics: an emerging threat to food security and human health. J Food Sci Technol. 2020 May;57(5):1601-1608.

Geyer R, Jambeck JR, Law KL. Production, use, and fate of all plastics ever made. Sci Adv. 2017 Jul 19;3(7):e1700782.

Jenner LC, Rotchell JM, Bennett RT, Cowen M, Tentzeris V, Sadofsky LR. Detection of microplastics in human lung tissue using μFTIR spectroscopy. Sci Total Environ. 2022 Mar 29;831:154907.

Luqman A, Nugrahapraja H, Agung Wahyuono R, Islami I, Husain Haekal M, Fardiansyah Y, Qonita Putri B, Skhlasul Amalludin F, Ainur Rofiqa E, Gotz , Tri Wibowo A. Microplastic contamination in human stools, foods, and drinking water associated with Indonesian coastal population. Environments 2021;8:138.

Schwabl P, Köppel S, Königshofer P, Bucsics T, Trauner M, Reiberger T, Liebmann B. Detection of Various Microplastics in Human Stool: A Prospective Case Series. Ann Intern Med. 2019 Oct 1;171(7):453-457.

Van Cauwenberghe L, Claessens M, Vandegehuchte MB, Janssen CR. Microplastics are taken up by mussels (Mytilus edulis) and lugworms (Arenicola marina) living in natural habitats. Environ Pollut. 2015 Apr;199:10-7.

Vethaak AD, Legler J. Microplastics and human health. Science. 2021 Feb 12;371(6530):672-674.

Wright SL, Kelly FJ. Plastic and Human Health: A Micro Issue? Environ Sci Technol. 2017 Jun 20;51(12):6634-6647.

Yee MS, Hii LW, Looi CK, Lim WM, Wong SF, Kok YY, Tan BK, Wong CY, Leong CO. Impact of Microplastics and Nanoplastics on Human Health. Nanomaterials (Basel). 2021 Feb 16;11(2):496.

Zarus GM, Muianga C, Hunter CM, Pappas RS. A review of data for quantifying human exposures to micro and nanoplastics and potential health risks. Sci Total Environ. 2021 Feb 20;756:144010.

Zhang Q, Xu EG, Li J, Chen Q, Ma L, Zeng EY, Shi H. A Review of Microplastics in Table Salt, Drinking Water, and Air: Direct Human Exposure. Environ Sci Technol. 2020 Apr 7;54(7):3740-3751.

Poisoned?

Call 1-800-222-1222 or

HELP ME online

Prevention Tips

  • Avoid use of single-use plastic products such as takeout food containers and disposable utensils.
  • Use biodegradable materials to reduce environmental waste.
  • Consider using a water filter to eliminate contaminants from drinking water.

This Really Happened

Eight healthy men and women (age range 33-65 years) participated in a study to assess the presence of microplastics in the human body. Seven of the study participants admitted to drinking from plastic bottles daily, and several had used cosmetic products that contained plastic polymers. Each participant provided a stool sample which was then assessed for the presence of microplastics. Three to seven microplastics of various sizes and shapes were detected in each stool sample, suggesting that ingestion of microplastics is common in humans.