Urgent warning for seafood lovers as scientists discover dangerous microplastics in six popular species, with shrimp the worst offenders

The next time you eat your favorite seafood, it might not just be the shell that gives it an unexpected crunch.

A worrying new study reveals the presence of microplastics in six types of fish and seafood commonly consumed by humans.

Microplastics – plastic fragments smaller than 5mm in diameter, invisible to the naked eye – have been linked to toxic effects on the body, such as cancer.

Scientists in Oregon conducted a laboratory analysis of more than 1,800 individual marine animals, including Pacific herring and a species of Pacific salmon.

In total, microplastics were found in 99 percent of the samples, in their intestines or even in their tissues – but no more than in the pink shrimp.

Scientists warn that the strange fragments travel ‘from the ocean to our kitchen table’ before being consumed by people in restaurants and homes.

“It is very concerning that microfibers appear to move from the gut to other tissues such as muscle,” says Professor Susanne Brander, an ecotoxicologist at Oregon State University.

‘This has major consequences for other organisms, possibly also for humans.’

Pink shrimp, which filter just below the water’s surface, had the highest concentrations of particles in their edible tissues, the study found

The researchers found man-made particles in the edible tissue of six species: (clockwise from top left) Chinook salmon, lingcod, black rockfish, pink shrimp, Pacific herring and Pacific lamprey

The researchers found man-made particles in the edible tissue of six species: (clockwise from top left) Chinook salmon, lingcod, black rockfish, pink shrimp, Pacific herring and Pacific lamprey

For the study, six fish were caught by a fishing vessel in Oregon waters or purchased from a supermarket or fishmonger.

In total, the researchers sampled 182 individual fish from the six species: pink shrimp, Pacific herring, Pacific lamprey, black rockfish, lingcod and Chinook salmon.

The six species are “economically or culturally important” in Oregon, but do not necessarily represent global eating habits.

Laboratory dissection and microscopic analysis revealed 1,806 suspicious particles in the vast majority of individual samples – 180 of 182, or 98.9 percent.

The fish contain a wide range of anthropogenic particles (APs), a broad category of materials produced or modified by humans.

Microplastics – plastic fragments with a diameter smaller than 5 mm, invisible to the naked eye – fall under the category of APs.

The study found 1,806 suspicious particles in 180 of 182 individual samples – mainly fibers, but also fragments and films.

According to the researchers, the smaller marine species tend to contain a higher amount of particles, but the reason for this is unclear.

Pink shrimp, which filter just below the water surface, had the highest concentrations of anthropogenic particles (APs) in their edible tissues (R = retail, V = barrel). Chinook salmon had the lowest concentrations. AP concentrations were also quite low in black rockfish and cod

Pink shrimp, which filter just below the water surface, had the highest concentrations of anthropogenic particles (APs) in their edible tissues (R = retail, V = barrel). Chinook salmon had the lowest concentrations. AP concentrations were also quite low in black rockfish and cod

Pacific lamprey (pictured) is a culturally important food source for the indigenous peoples of the Pacific Northwest

Pacific lamprey (pictured) is a culturally important food source for the indigenous peoples of the Pacific Northwest

Black rockfish (pictured) are harvested in Oregon, California, Washington, British Columbia, Alaska and the Pacific

Black rockfish (pictured) are harvested in Oregon, California, Washington, British Columbia, Alaska and the Pacific

Food and drinks appear to contain microplastics

  • Seafood
  • Meat (pork, beef and chicken)
  • Vegetables and fruits
  • Tofu
  • Vegetarian burgers
  • Sugar
  • Honey
  • Beer
  • Tea
  • Bottled water

…and much more

Shrimp and small fish, such as herring, eat smaller food items such as zooplankton, the small swimming animals at the bottom of the marine food chain.

“Other studies have found high concentrations of plastic in the area where zooplankton accumulate,” said study author Professor Elise Granek of Portland State University.

‘These anthropogenic particles may resemble zooplankton and thus be ingested by animals that feed on zooplankton.’

Despite the findings, the researchers are not advising people to stay away from seafood.

Microplastics are ubiquitous and have been found in bottled water, beer, honey, beef, chicken, veggie burgers and tofu.

Therefore, eliminating seafood from your diet is unlikely to stop your consumption of microplastics.

“When we throw away and use products that release microplastics, those microplastics end up in the environment and are absorbed by the things we eat,” says Professor Granek.

‘What we throw into the environment ends up on our plates.’

The Chinook salmon (photo) is the largest and most valuable species of Pacific salmon. It is eaten by both humans and wild animals such as killer whales and sea lions

The Chinook salmon (pictured) is the largest and most valuable species of Pacific salmon. It is eaten by both humans and wild animals such as killer whales and sea lions

According to Wild Alaskan Company, Lingcod (pictured) is a relatively large species of groundfish with habitats in the Pacific Ocean

According to Wild Alaskan Company, Lingcod (pictured) is a relatively large species of groundfish with habitats in the Pacific Ocean

There are about 200 different species of herring, although only three are caught for food: Atlantic, Pacific (pictured) and Araucanian.

There are about 200 different species of herring, although only three are caught for food: Atlantic, Pacific (pictured) and Araucanian.

Microplastics – plastic particles with a diameter smaller than 5 millimeters – can come from larger plastic products that have broken down, textile fibers, cigarette filters or even beauty products (file photo)

Microplastics – plastic particles with a diameter smaller than 5 millimeters – can come from larger plastic products that have broken down, textile fibers, cigarette filters or even beauty products (file photo)

Other fish likely contain microplastics as well, but the study focused on six species commonly consumed in Oregon.

It’s not the first time microplastics have been found in seafood, or even food in general.

A 2020 study discovered microplastics in every sample of seafood purchased at a market: squid, shrimp, oysters, crabs and sardines.

The following year, an Australian scientist demonstrated on TikTok how microplastics are contained in store-bought fish sticks.

Studies have reported the presence of microplastics in several foods, including salt, seafood, sugar, beer, bottled water, honey and milk.

The human health risks of ingesting microplastics and other APs are under-researched, but have been linked cancerDNA damage and cellular damage.

What are microplastics?

Microplastics are defined as small pieces of plastic less than 5mm long, about the size of a sesame seed.

There is an even smaller type of microplastic – nanoplastic – which is the result of microplastics that break down even further and are smaller than 100 nanometers (nm).

The most common sources of microplastics entering the environment are surface water after heavy rainfall or flooding, treated and untreated wastewater, industrial wastewater, sewage overflows and atmospheric deposition.

Primary and secondary microplastics

Primary microplastics are deliberately manufactured in microplastic size for industrial abrasives used in sandblasting, as well as microbeads used in cosmetics and skin care products.

Secondary microplastics are formed by the weathering of larger plastic objects after they have been released into the environment.

Credit: Choice.com.au