What are microplastics?

Microplastics are plastic pieces or fibers that are smaller than 5 millimeters (mm) in size, or about the size of a pencil eraser, and smaller. These pieces can be so small that they fit on the tip of your finger. Some can’t even be seen with the human eye! There are many types of microplastics, including beads, fragments, pellets, film, foam, and fibers.

Some microplastics are made to be small for a specific purpose. Often called primary microplastics, these tiny pellets are melted and used to create larger plastic items. In fact, most common plastic items are made from these pellets, from water bottles to holiday decorations. Another example are microbeads that may be found in personal care products, such as toothpaste, face washes, and cosmetics. The Microbead-Free Waters Act of 2015 banned microbeads in “rinse off” products (like face wash or toothpaste). However, these products could still be sold until 2019. Manufacturers can also still use microbeads in other products like makeup or styling products that are not considered “rinse off.”

Secondary microplastics come from larger pieces of plastics, such as beverage bottles, bags, and toys. Sun, heat, wind, and waves can cause these plastics to become brittle and break into smaller and smaller pieces that may never fully go away. Microplastics are also created when pieces of plastic break off during regular use. For example, bits of tires can break off while driving and wash into rivers and oceans from the rain.

Secondary microplastics also come from places you'd never expect, like your clothing! Clothes, furniture, and fishing gear made from synthetic materials all produce plastic microfibers. These fibers are extremely common on shorelines everywhere, and come from synthetic materials, such as polyester or nylon. Through general wear or washing and drying, these tiny fibers break off and shed from larger items.

You can find microplastics throughout the ocean, from tropical waters to polar ice, fresh water, and the air we breathe. As you might expect, animals often swallow microplastics. Microplastics have even been found in tap and bottled water, sea salt, and many other products we eat and drink.

Scientists around the world are still trying to understand exactly how microplastics end up in so many parts of our environment, and how they may affect wildlife and people.