Science Made Simple: What Are Microplastics?

Microplastics are fragments of any type of plastic that are less than 5 mm (0.20 in) in length.

Microplastics are small plastic pieces less than five millimeters long which can be harmful to our ocean and aquatic life.

Plastic is the most prevalent type of marine debris found in our oceans and Great Lakes. Plastic debris can come in all shapes and sizes, but those that are less than five millimeters (0.2 inches) in length (or about the size of a sesame seed) are called “microplastics.”

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Microplastics can come from a variety of sources including larger plastic pieces that have broken apart, resin pellets used for plastic manufacturing, or in the form of microbeads, which are small, manufactured plastic beads used in health and beauty products.

As an emerging field of research, not a lot is known about microplastics and their impacts yet. The NOAA Marine Debris Program is leading efforts within NOAA to study this topic. Standardized field methods for collecting sediment, sand, and surface-water microplastic samples have been developed and continue to undergo testing. Eventually, field and laboratory protocols will allow for global comparisons of the amount of microplastics released into the environment, which is the first step toward determining the final distribution, impacts, and fate of this debris.


What are microplastics? Here’s what you need to know in less than a minute.

Microplastics come from a variety of sources, including from larger plastic debris that degrades into smaller and smaller pieces. Additionally, microbeads, a type of microplastic, are very tiny pieces of manufactured polyethylene plastic that are added as exfoliants to health and beauty products, such as some cleansers and toothpastes. These tiny particles easily pass through water filtration systems and end up in the ocean and Great Lakes, posing a potential threat to aquatic life.

Toothpaste Close Up

Microbeads are tiny pieces of polyethylene plastic added to health and beauty products, such as some cleansers and toothpastes.

Microbeads are not a recent problem. According to the United Nations Environment Program, plastic microbeads first appeared in personal care products about fifty years ago, with plastics increasingly replacing natural ingredients. As recently as 2012, this issue was still relatively unknown, with an abundance of products containing plastic microbeads on the market and very little awareness on the part of consumers.

On December 28, 2015, the Microbead-Free Waters Act of 2015 was signed by President Obama, banning plastic microbeads in cosmetics and personal care products.