Unit 4: Plastics

Microplastics: a not so tiny problem

Essential question: 

What are the issues related to plastic consumption and how does plastic pollution impact the environment including the Columbia River?

Learning objective: 

Students will be able to:

  1. Define the problems associated with plastics and microplastics.
  2. Understand the factors contributing to the problem.
  3. Identify solutions.

Next Generation Science Standards:

NGSS Disciplinary Core Ideas (Grades 6-8)

  • MS-ESS3 Earth and Human Activity
  • MS-LS2 Ecosystems: Interactions, Energy, and Dynamics
  • MS-PS1 Matter and Its Interactions


So, what’s the problem with plastics, anyway?

Plastics are human-made chains of hydrocarbons made from non-renewable resources like oil, gas, and coal. These fossil fuels are the building blocks for plastics, and their extraction makes plastics possible. Fossil fuel extraction has enormous climate-change impacts, but the essential issue with plastics is that once we make them, they don’t go away.

You might be inclined to think recycling is a viable solution, but consider this: as of 2015 the world had created 6.3 billion tons of plastic waste and 91% of that has never been recycled.1 Plastic doesn’t biodegrade. It does, however, photodegrade, which means the sun’s UV rays cause the plastic to break down into smaller and smaller pieces. As pieces get smaller, plastics become more and more difficult to remove from the environment. You may have read about the astronomical amount of plastic in the oceans or the “Great Pacific Garbage Patch” and pictured a giant floating island of plastic, but some researchers say the marine plastic issue is better described as a “plastic smog” of microplastics.2

Microplastics are plastic debris measuring less than five millimeters. They can come from larger plastics that break apart, fibers from synthetic clothing (like nylon, fleece, or polyester) that come off in the washing machine, or personal care products (like toothpaste and exfoliating face washes) that contain microbeads.* As these plastics degrade they can leach harmful chemicals into the environment. And these plastics, microplastics, and toxic chemicals aren’t just harming the ocean, they’re polluting our rivers and streams as well, including the Columbia River. In fact, they’re even in the food we eat like oysters, clams, and other shellfish.3

While plastics research on freshwater rivers is more limited compared to marine environments, studies have detected microplastics in the Columbia River. One study that looked at four Oregon rivers (the Columbia, Willamette, Deschutes, and Rogue) found microplastics in every single sample from every single site, despite the fact that their sites included remote and undeveloped stretches of river.4 Unfortunately, microplastics, even  in the Columbia River, are proving to be incredibly pervasive.

Research shows municipal water treatment plants are a major source of microplastic pollution entering waterways,5 but that plastic isn’t coming from the wastewater treatment plant. It’s coming from us. The wastewater treatment plants can’t filter all those tiny plastic particles. There’s only one source of plastic in the environment: humans.

How is plastic pollution getting into the river?
  • Litter
  • Storm sewer and wastewater treatment (anything that goes down the drain goes to the river, this includes microfibers from synthetic clothing—like fleece, nylon, and polyester—that break off in the washing machine). 
There’s no single way to solve our plastic problems, but there are some things you can do:
  • Limit personal plastic use. Check out these 100 tips on how to go plastic-free or check out Plastic Free July for more ideas.
  • Clean up plastic litter. Join a cleanup or collect trash on your own when you see it.
  • Advocate for government action and for companies to use less plastic. 
  • Educate yourself on the problems with plastic recycling.
  • Be creative and think about small- and large-scale solutions.
  • Get inspired! Teens like this one are helping to develop ways to remove microplastics from the environment


* Congress passed the Microbead-Free Waters Act of 2015, banning the manufacture and sales of “rinse off cosmetics” with plastic microbeads.

Plastics Activities

Explore hands-on and thought-provoking activities

  • Biodegrade – to be decomposed by bacteria or other living organisms
  • Degradation – the process of objects breaking down
  • Photodegradation – degradation of a material by UV light
  • Plastics – manufactured chains of hydrocarbons called polymers. Hydrocarbons usually come from petroleum or natural gas.
  • Polyethylene – the most common type of plastic, with a wide variety of uses, including packaging, shopping bags, and clothes
  • Microbeads – small plastic beads used in personal care products such as toothpaste, body wash, and face wash. Microbeads are commonly made out of polyethylene and are designed to wash down the drain and are too small to be captured by water treatment facilities. Congress passed the Microbead-Free Waters Act of 2015, banning the manufacture and sales of personal care products with plastic microbeads.
  • Microplastics – plastic debris measuring less than 5mm, can be broken bits, fibers, or fragments
  • Weathering – Mechanical weathering is the process of breaking down materials into smaller pieces (by wind, waves, etc.)

Link to all Pollution Prevention Vocabulary Terms

Additional Resources:  

This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement RB 01J73501 to Columbia Riverkeeper. The contents of this website subpage do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does the EPA endorse trade names or recommend the use of commercial products mentioned in this document.