Presence Of Microplastics In Commonly Eaten Fish Described As 'Very Concerning'

Microplastics and other human-made particles have been found everywhere from Arctic snow to the breath of dolphins to meat and milk from animals. Now, new research has uncovered these tiny particles in six species of fish that are commonly eaten in the US, particularly Oregon.

Researchers from Portland State University (PSU) tested samples of edible flesh from fishes bought by grocery stores and caught at sea. The species were black rockfish, lingcod, Chinook salmon, Pacific herring, Pacific lamprey, and pink shrimp. They are found off the coast of Oregon in the North Pacific Ocean.

Testing found 1,806 suspected particles in 180 out of 182 samples. Fibers, which often shed from clothes when washed, made up 82 percent of the particles discovered. The remained of particles were almost entirely plastic fragments.

“It’s very concerning that microfibers appear to move from the gut into other tissues such as muscle,” study co-author Susanne Brander, a professor in environmental toxicology at Oregon State University, told Scitech Daily. “This has wide implications for other organisms, potentially including humans too.”

Previous studies have found microplastics in bivalves such as mussels and in the gastrointestinal tracts of fishes and crustaceans. The new study adds to the picture of how ubiquitous microplastic contamination is by showing that particles also make their way into muscle tissue of marine species.

Shrimp most contaminated

ink drop – stock.adobe.com Chinook salmon had the least microplastics in their flesh

Shrimp is the most consumed species of aquatic animal in the US. Among the species tested in the Oregon study, pink shrimp had the highest concentrations of particles in their flesh. They filter-feed just below the water surface and so may be more exposed to particle pollution.

“We found that the smaller organisms that we sampled seem to be ingesting more anthropogenic, non-nutritious particles,” Dr. Elise Granek, one of the study’s authors who runs the PSU Applied Coastal Ecology Lab, told Scitech Daily. “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.”

Chinook salmon had the least amount of particles in their flesh, followed by black rockfish and lingcod.

The researchers warn that microplastics contain chemical additives and can absorb chemicals from the environment. These chemicals can leach into the body of marine animals who ingest microplastics, causing gut damage, oxidative stress, and adverse immune responses in the animals.

In addition to the issue of microplastics, a growing number of people are moving away from eating fishes on ethical and environmental concerns. The fishing industry is hugely destructive to the ocean, and there is growing evidence that fishes are sentient and have complex minds and abilities.