Enjoy Eating Fish? A New Study Reveals Which Seafood Has the Most Microplastics

Microplastics have made their way into the seafood aisle.

From Sweater to Sushi?

As your favorite fleece spins through the wash, a nearly invisible plastic fiber breaks free. It slips down the drain, too small to catch, and flows into the wastewater treatment plant. These microplastics, tiny synthetic fibers thinner than human hair, are shed from clothes made with materials like polyester and nylon. It may not seem like it, but studies show that the #1 source of microplastic pollution is laundry, accounting for 35% of all microplastic pollution in the ocean. Filters at wastewater treatment plants catch most solids, but not these. They pass through, drift into rivers, and ride the current out to sea.

Out in the open ocean, they sink and swirl, mixing into the water column where small fish feed. Unfortunately, the fish can’t notice the difference. They eat as they always do, drawing in food along with whatever else is floating nearby. Over time, hundreds of microplastic fibers build up inside them. That same fish is hauled in by a commercial net, packed in ice, and delivered to the seafood counter. Later, you cook it for dinner, never realizing what came with it.

New Study Analyzes Microplastics in Seafood

A new peer-reviewed study published in the Marine Pollution Bulletin brings together years of research to show just how widespread microplastic contamination in seafood has become. An estimated 14 million tons of plastic enter the ocean each year, and much of it breaks down into microscopic fragments that are nearly impossible to remove.

The study states that microplastics have been found in over one-third of fish in the English Channel, and in as many as 92 percent of fish species along the coast of China. Shellfish like clams, oysters, and mussels, often eaten whole, have also tested positive, with European consumers estimated to eat up to 11,000 microplastic particles per year.

Which Sea Animals Have the Most Microplastics?

As small fish consume contaminated plankton or snails, and larger fish eat those smaller ones, plastic particles move up the food chain. This is known as trophic transfer, and it means that predatory fish like cod or trout tend to have more microplastics in their bodies than fish like minnows that are lower on the food web. The process happens slowly, but over time, plastic consumption builds up in the body, a phenomenon called bioaccumulation. In one review, predatory fish had an average of over four microplastic particles per individual, while smaller fish carried around two to three. The study also found that wild fish collected near urban wastewater outlets may accumulate more microplastics than farmed fish. When you eat these fish, the particles may transfer to your body too.

For humans, the risk of exposure rises not just with fish higher up the food chain, but also with feeder species like clams, mussels, and crabs. Shellfish like mussels and clams, which filter water all day, can accumulate up to 11,000 microplastic particles per year while crabs may ingest as many as 15,000 particles a day.

Bioaccumulation and trophic transfer of microplastics in aquatic ecosystems (Jangid et al. 2025). https://doi.org/10.1016/j.marpolbul.2025.118279

Should You Be Concerned?

Although we do not yet fully understand the health effects of consuming microplastics, research has already linked them to inflammation, hormone disruption, and the potential to carry toxic chemicals into the body. These concerns are especially relevant when microplastics break down into even smaller particles, called nanoplastics, which can enter organs and tissues more easily.

So, the next time you bring home fresh cod from the market or crack open a crab at the seafood boil, it’s worth remembering that you might be getting more than just protein. Microplastics are entering our food not because of anything we did wrong, but because plastic has become woven into the fabric of our daily lives and into the very ecosystems we rely on. While avoiding seafood altogether is not a practical solution, understanding how microplastics can enter our bodies from the food we eat is a starting point to address a growing problem we can no longer ignore.

How You Can Help

You can stop the spread of microplastic pollution from your home before it even starts. Before a net scoops up the fish, before the fish ingests hundreds of microplastics, and even before the microplastics slip through the wastewater treatment plant, CLEANR’s Premium Microplastic Filter for washing machines captures 90%+ of microplastics before they leave your house, stopping the pollution at its source.

Learn More!

About CLEANR

CLEANR builds best-in-class microplastic filters for washing machines that effortlessly remove the largest source of microplastics into the environment. Its technology, VORTX, represents a breakthrough in filtration, with a patent-pending design that is inspired by nature and proven to outperform conventional filtration technologies by over 300%. The company is building a platform filter technology that enables product manufacturers and business customers to materially reduce their microplastic emissions from impacted in-bound and out-bound fluid streams, including residential and commercial washing machine wastewater, in-home water systems, wastewater treatment, textile manufacturing effluents, industrial wastewater, and other sources. www.cleanr.life

Sources:

Jangid, H., Dutta, J., Karnwal, A., & Kumar, G. (2025). Microplastic contamination in fish: A systematic global review of trends, health risks, and implications for consumer safety. Marine Pollution Bulletin, 219, 118279. https://doi.org/10.1016/j.marpolbul.2025.118279
Ullah, S., Ahmad, S., Guo, X., Ullah, S., Ullah, S., Nabi, G., & Wanghe, K. (2023, January 16). A review of the endocrine disrupting effects of micro and nano plastic and their associated chemicals in mammals. Frontiers in Endocrinology, 13, 1084236. https://doi.org/10.3389/fendo.2022.1084236

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