What Are Microplastics?

Updated: May 12, 2024

Microplastics are pervasive in the air, soil, water — and our homes. Learn about where they come from, where they're found and the harm they can cause.

What do your snugly blanket, refreshing bottle of water and favorite soup bowl have in common? They’re probably all infusing your body with microplastics. In a recent study, scientists estimated we inadvertently consume about a credit card’s worth of plastic particles per week.

“You are probably eating, drinking and breathing in between 78,000 and 211,000 microplastic particles every year, and even this is considered an underestimate,” says Erica Cirino, communications manager of Plastic Pollution Coalition. That translates to somewhere between 0.1 and five grams of plastic per week.

Beyond just being icky, it’s a problem because we don’t yet know what amount of microplastics, if any, is safe for us to consume. Here’s what to know about them so you can learn how to avoid microplastics at home.

What Are Microplastics?

Microplastics are pieces of plastic smaller than five millimeters (mm) and bigger than 0.0001-mm.

“For context, that is smaller than the size of the eraser on the end of a pencil, down to one-thousandth the width of a human hair,” says Fay Couceiro, Ph.D., a professor of environmental pollution at the University of Portsmouth in the United Kingdom.

Microplastics and their even smaller counterparts, called nanoplastics, are so widespread they’ve been found on the highest mountain peaks, in the deepest ocean trenches, and in the rain that waters our crops. They travel easily through air and water, delivering toxic chemicals that contaminate streams, oceans, soils, plants and animals, including humans.

Where Do Microplastics Come From?

When anything made of plastic is exposed to natural processes like sunlight, water, microbes, extreme temperatures, wind and waves, it begins breaking up into microplastics. This is where all of those tiny little plastic bits on a beach come from.

But microplastics also enter the environment through our drains. Every time we wash our clothes and dishes, particles enter the water supply. Most water treatment plants aren’t equipped to remove them.

At home, microplastics are introduced into our air and food through products ranging from cutting boards and food packaging to clothes and carpets. Still more microplastics come from microbeads intentionally added to personal care products, including toothpaste and body wash.

“Often people think microplastics are just in the water, and that if we avoid fish we will not eat them,” says Couceiro. “Microplastics are unfortunately everywhere, in our waters, soils and air.”

Are Microplastics Harmful?

Yes. Many studies have shown how microplastics harm fish and other aquatic animals, through their physical presence and the toxins they transport. New studies are also beginning to prove they’re damaging to animals and plants.

“We are still in the early days of research into human health impacts, but the indications are similar,” says Couceiro. Dangers to humans could include increased risk of cancer, inflammation, decreased gut health, oxidative stress, reproductive toxicity and changes in metabolism.

Plastic particles pollute our bodies through many different pathways including through our skin, and when we eat, drink and breathe,” says Cirino. “The full range of detrimental effects of plastics and plastic particles on humans and nature is just beginning to be understood — and is already proving to be serious.”

We’re also learning how pervasive they are in our bodies. They’ve been found in human placentas, lungs and other organs, bloodstreams, breast milk, testes and semen.

“Thousands of chemicals are added to plastic to give it properties like pliability, durability, fire-resistance, antimicrobial, UV resistance and color,” says Melissa Valliant, communications director of Beyond Plastics. “Many of these common additives are known to be hazardous to human health.

“What’s more, only a fraction of the thousands of chemicals added to plastic, many of which are not disclosed, have been evaluated for their toxicity.”

Are Microplastics In Food?

Yes, microplastics are found in many of our foods, including:

  • Meat, fish and dairy: According to a recent study, nearly 80% of products tested from farm animals contain microplastics.
  • Fruits and vegetables: Plants absorb microplastics in water through their roots. Apples and carrots have the highest levels, but they’re found in many other crops as well.
  • Processed foods: Processing and packaging introduces microplastics into food, including cereals and crackers.
  • Beer and wine: Studies found alcoholic beverages, especially those in containers with polyethylene stoppers, can contain microplastics.
  • Water: “Microplastics in bottled water largely come from the plastic cap and the bottle,” says Tasha Stoiber, a senior scientist at the Environmental Working Group. Tap water can also contain them. But some filters, especially reverse osmosis models, can remove them.
  • Condiments: Table salt, honey, fish sauce and any condiments sold in plastic containers can contain microplastics.
  • Tea and coffee: Some tea bags contain plastic, as do single-use coffee-brewing cups.

What Products Contain Microplastics?

Unfortunately, a massive amount. Anything made with some form of plastic can spread them, including synthetic clothing, plastic spatulas and single-use plastic bags.

Some of our highest exposure comes from foods and drinks. But other items spread microplastics into the air in our homes, where we breathe them in, or they settle on our food.

Common sources for microplastics in the home include:

  • Clothing with synthetic fibers;
  • Furniture, including sofas and chairs;
  • Carpets and rugs;
  • Pillows and bedding;
  • Vehicle tires and interiors;
  • Plastic and rubber cookware, bowls, cups and utensils;
  • Single-use plastic food bags and wrappers;
  • Water and other beverages bottled in plastic;
  • To-go containers.