Someone picking up a plastic water bottle at the beach
Larger items left behind on the beach can break down into microtrash and microplastics.

The sun is shining and the wind is keeping you cool as you relax on Lake Washington — ahhh, summer is finally here! The sand moves through your toes as you soak up the warm weather when that all too familiar experience jars you out of your summer lullaby… a cigarette butt, stuck in your toes where the sand should be cascading through. You look around you and see more than just the single cigarette butt: food wrappers, broken toys, bottle caps and other various discarded plastic packaging riddle the beach, otherwise known as microtrash.

“Microtrash or microplastics sound like a small problem, but it’s actually a problem that is getting bigger and bigger. Most of our trash is made of some kind of plastic, and plastics do not breakdown naturally in the environment and can in fact last for thousands of years,” says Randie Bundy, assistant professor of Oceanography.

Over the years microplastics have become a subject we’re all familiar with, but often overlooked and discussed with less urgency is microtrash. Trash left behind on beaches, at parks and on trails break down over time into small pieces, or microtrash. The empty tortilla chip bag and plastic salsa container lid might not seem like a huge deal, but that microtrash then breaks down into many small pieces of microplastics, which are defined as particles less than 5 millimeters.

The chips and salsa remnants, the cap from a kombucha bottle and forgotten toys all contribute to the millions of pieces of microtrash found in our lakes, rivers and oceans. It accumulates over time and builds up in our watersheds, and when the inevitable annual rain comes around and the snowpack melts, all the tiny pieces of trash enter lakes, rivers and creeks. One study along the St. Lawrence River found up to a shocking 1,285 microplastic particles per square foot of river sediment. Another study found that one serving of cultured oysters can contain up to 50 particles. Much of this ends up in the ocean; it’s estimated that the Great Pacific Garbage Patch contains nearly two trillion pieces of trash, nearly all of it plastic.

Not only does the problem of microtrash magnify as we move from shore front to ocean, but it magnifies up the food chain as well in a process known as bioaccumulation. Small organisms will ingest a miniscule amount of trash, which may not seem like a big deal. Yet these animals are consumed by larger ones, who are then consumed by even larger ones, and all of a sudden giant marine mammals like our beloved resident orcas are reaping the consequences from a seemingly harmless summertime picnic at the beach.

In a 2020 study, researchers found that Dungeness crabs contain on average about 0.35 milligrams per gram of microplastics, and the average size crab weighs 500 grams. This gets passed on to the salmon that consume the crab, then gets passed on to the orca consuming the salmon. Resident orcas in the Salish Sea eat between 18 and 25 salmon per day, and without the ability to shed plastics they accumulate in their flesh. Ingestion of microtrash is a serious health risk for all organisms, leading to digestion issues, infection, behavioral changes, nutritional deficiencies and more. The more chronic exposure to microtrash an organism has, the more detrimental and even lethal these effects can be.

Julie Masura, a researcher at UW Center for Urban Waters, has been researching microplastics for the past decade in Puget Sound. Surprisingly, Julie and her students have found that despite an increase in plastic production over the last decade, plastics have not been accumulating in Puget Sound over time. Her research group hypothesized that plastics entering the Puget Sound via rivers and runoff water end up ingested by organisms, sink into sediments and get sent out into the Pacific Ocean.

“I think it’s important for all of us to pack out what we pack in, and leave no trace,” says Bundy. “Not only is it important for our ecosystems, it’s good for all of us too. Who wants to see trash on the beach when we’re in a beautiful place?” In fact, recently a student in Bundy’s marine pollution class organized a beach clean-up that is now set to continue once a month.

Actions: What can you do?

Having a critical eye for trash around you and picking up your own trash is crucial to healthy waterways, uncontaminated oceans and the health of vulnerable species like orcas, salmon and shellfish. Here are some action items you can take to help:

  • Think about what you’re packing on your next beach outing or hike. Can some of your food be placed in reusable containers?
  • Can you pack a trash bag when you picnic and collect trash other may have left behind?
  • Recycle single-use plastics as much as you can.
  • Participate in a trash clean up.
  • Although it’s fun, don’t release balloons in air.
  • Enter your zip code to find your local designated plastic drop-off center.
  • Contact your marine debris program’s regional coordinator for more information on microtrash in your area.
  • Find ways to reduce plastic use in your everyday life, as 80% of ocean-based plastics originate from land.