Microplastics Are Widespread in Popular Types of Seafood, Study Shows

Microplastics shed from plastic products like clothing and packaging are ending up in the fish we eat, according to researchers from Portland State University (PSU).

The findings of the study highlight a need for strategies and technologies to reduce the microfiber pollution that makes its way into the environment, a press release from PSU said.

“Microplastics (MPs) and other anthropogenic particles (APs) are pervasive environmental contaminants found throughout marine and aquatic environments. We quantified APs in the edible tissue of black rockfish, lingcod, Chinook salmon, Pacific herring, Pacific lamprey, and pink shrimp, comparing AP burdens across trophic levels and between vessel-retrieved and retail-purchased individuals,” the researchers wrote in the study. “Anthropogenic particles were found in 180 of 182 individuals… These findings suggest a need for further research into technologies and strategies to reduce microfiber pollution entering the environment.”

Scientists from the Applied Coastal Ecology Lab at PSU built on earlier research that explored the pervasiveness of microplastics in bivalves such as Pacific razor clams and oysters, the press release said. Led by Elise Granek, an environmental science and management professor, the team focused on commonly eaten crustaceans and finfish.

Their goal was to fill in the gaps regarding microplastic contamination in shellfish and finfish in Oregon, while gaining a better understanding of differences across trophic levels — which arrange the position of fish in the food chain — as well as in pathways to consumers.

The researchers quantified particles from materials modified or produced by humans that they discovered in the edible tissues of half a dozen species that are culturally or economically important in Oregon: Chinook salmon, lingcod, black rockfish, Pacific lamprey, Pacific herring and pink shrimp.

The team then compared concentrations of particles across trophic levels, as well as whether where the microplastics were positioned in the food web had an effect on how much and what was contaminating the edible tissue of the fish. They also looked at whether samples obtained directly from research vessels differed from those of seafood vendors and supermarkets.

The researchers found 1,806 suspected plastic particles in 180 out of 182 individual samples. Fibers were most abundant, followed by films and fragments.

The study, “From the ocean to our kitchen table: anthropogenic particles in the edible tissue of U.S. West Coast seafood species,” was published in the journal Frontiers in Toxicology.

Of the species the research team sampled, pink shrimp were found to have the highest particle concentrations in their edible tissues. The lowest concentrations were found in Chinook salmon, followed by lingcod and black rockfish.

“We found that the smaller organisms that we sampled seem to be ingesting more anthropogenic, non-nutritious particles,” Granek said in the press release. “Shrimp and small fish, like herring, are eating smaller food items like zooplankton. Other studies have found high concentrations of plastics in the area in which zooplankton accumulate and these anthropogenic particles may resemble zooplankton and thus be taken up for animals that feed on zooplankton.”

The team expected processing would introduce more contaminants from plastic packaging, but that was not found to be universally true. The researchers also discovered that rinsing shrimp and fish fillets — as many people do before preparing them — could, in some cases, remove additional contamination that might have landed on the surface between catch and consumer.

Overall, the study provided evidence of widespread plastic particles and fibers in the edible tissues of marine and freshwater species in Oregon.

“It’s very concerning that microfibers appear to move from the gut into other tissues such as muscle,” Susanne Brander, an ecotoxicologist with Oregon State University who helped with lab analysis, said in the press release. “This has wide implications for other organisms, potentially including humans too.”

The researchers said the findings demonstrate the need for more studies to understand how particles end up in muscle tissue, along with policies to regulate anthropogenic particles.

“This project established critical baseline data for West Coast fisheries stakeholders and highlighted how much we still do not know about these pervasive microplastic pollutants,” said Summer Traylor, who led the project with help from Marilyn Duncan, an environmental science student who graduated from PSU in 2024. Traylor graduated with a master’s in environmental management in 2022 and is now a NOAA Corps Officer.

Rather than recommending people avoid seafood, the authors of the study are instead focusing on solutions.

“If we are disposing of and utilizing products that release microplastics, those microplastics make their way into the environment, and are taken up by things we eat,” Granek said. “What we put out into the environment ends up back on our plates.”

“We’re continuing to do work to understand the effects of anthropogenic particles on animals, but we’re also moving into experimental work to test what are effective solutions to reduce microplastics entering marine ecosystems,” Granek added.