Next time you chomp down on your favourite seafood, it may not just be the shell that gives it an unexpected crunch.
A concerning new study reveals the presence of microplastics in six species of fish and seafood which are commonly consumed by humans.
Microplastics – plastic fragments less than 5 mm in diameter, invisible to the naked eye – have been linked with toxic impacts on the body, such as cancer.
Scientists in Oregon conducted a lab analysis of more than 1,800 individual marine creatures, including Pacific herring and a species of Pacific salmon.
In all, microplastics were found in 99 per cent of samples, in their gut or even in their tissue – but none more so than the pink shrimp.
Scientists warn that the foreign fragments travel ‘from the ocean to our kitchen table’ before being consumed by humans in restaurants and homes.
‘It’s very concerning that microfibers appear to move from the gut into other tissues such as muscle,’ said Professor Susanne Brander, an ecotoxicologist at Oregon State University.
‘This has wide implications for other organisms, potentially including humans too.’
Pink shrimp, which filter-feed right below the surface of the water, had the highest concentrations of particles in their edible tissues, the study found
The researchers found human-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 bought from a supermarket or seafood vendor.
In all, the researchers sampled 182 individual fish of the six species – pink shrimp, pacific herring, pacific lamprey, black rockfish, lingcod and chinook salmon.
The six species are that are ‘economically or culturally important’ in Oregon but don’t necessarily represent global eating habits.
Lab dissection and microscopic analysis revealed 1,806 suspected particles across the vast majority of individual samples – 180 of 182, or 98.9 per cent.
The fish contained a wide range of anthropogenic particles (APs), a broad category of materials produced or modified by humans.
Microplastics – plastic fragments less than 5 mm in diameter, invisible to the naked eye – come under the category of APs.
The study found 1,806 suspected particles across 180 of 182 individual samples – mostly fibres but also fragments and films.
According to the researchers, the smaller marine species tend to contain a higher quantity of particles in them, but the reason for this exactly is unclear.
Pink shrimp, which filter-feed right below the surface of the water, had the highest concentrations of anthropogenic particles (APs) in their edible tissues (R = retail, V = vessel). Chinook salmon had the lowest concentrations. AP concentrations were also fairly low in black rockfish and lingcod
Pacific lamprey (pictured) are a culturally important food source for indigenous peoples of the Pacific Northwest
Black rockfish (pictured) are harvested in Oregon, California, Washington, British Columbia, Alaska, and the Pacific
Shrimp and small fish, like herring, eat smaller food items like zooplankton, the small swimming animals towards the bottom of the marine food chain.
‘Other studies have found high concentrations of plastics in the area in which zooplankton accumulate,’ said said study author Professor Elise Granek at Portland State University.
‘These anthropogenic particles may resemble zooplankton and thus be taken up by animals that feed on zooplankton.’
Despite the findings, the researchers are not advising people to stay away from seafood.
Microplastics are ubiquitous, having already been found in bottled water, beer, honey, beef, chicken, veggie burgers and tofu.
Therefore, omitting seafood from your diet is unlikely to stop your consumption of microplastics.
‘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,’ Professor Granek said.
‘What we put out into the environment ends up back on our plates.’
The Chinook salmon (pictured) is the largest and most valuable species of Pacific salmon. It is eaten by people as well as wildlife such as orcas and sea lions
Lingcod (pictured) is a relatively large species of ground fish with habitats in the Pacific Ocean, according to Wild Alaskan Company
There are around 200 different species of herring although it’s just three that are usually caught for food – Atlantic, Pacific (pictured) and Araucanian
Microplastics – plastic particles less than 5 millimetres in diameter – can come from larger plastic products that have broken down, textile fibres, cigarette filters or even beauty products (file photo)
Other fish are also likely to contain microplastics too, but the study focused on six species that are commonly consumed in Oregon.
It’s not the first time microplastics have been found in seafood, or even food in general for that matter.
A 2020 study discovered microplastics inside every single sample of seafood bought at a market – squid, prawns, oysters, crabs and sardines.
The following year, an Australian scientist demonstrated on TikTok how there’s microplastics in store-bought fish fingers.
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 understudied, but have been linked to cancer, DNA damage and cellular damage.
