A large proportion of fish intended for human consumption may contain microplastics, scientists have found, with one expert saying that deciding whether or not to eat fish is a “personal choice”.
According to an article published in the magazine Marine Pollution BulletinThree quarters of the fish caught off the coast of southern New Zealand contained some level of microplastics in their tissues.
Microplastics are tiny plastic fragments less than 0.2 inch in diameter.
“75% of the fish I sampled had ingested microplastics. I sampled fish in all seasons over a two-year period along the southeast coast of southern Aotearoa, New Zealand, from Oamaru to Te Waewae Bay,” said coastal scientist and study lead author Isabella Clere news week.
“I found a similar uptake rate between pelagic (surface dwellers) and benthic (bottom dwellers) fish, suggesting that plastics are ubiquitous throughout the water column and a persistent feature in the ocean.”
Corresponding National Geographicsome microplastics are tiny particles so large that they are used in cosmetics or microfiber clothing, while others are the result of the decomposition of larger pieces of plastic caused by environmental degradation.
According to a 2021 estimate from a study published in the journal microplastics and nanoplasticsthere are about 24.4 trillion pieces of microplastics in the world’s upper oceans, with a combined weight of 82,000 to 578,000 tons.
These microplastics find their way into most marine organisms, often through ingestion.
Clere’s New Zealand study found that 391 pieces of microplastic were removed from the 155 fish studied across 10 species. About 98 percent of the microplastic parts were smaller than 3 mm.
“We looked at a range of benthic (bottom-dwelling) and pelagic (surface-dwelling) fish and found microplastics in the gut of all species, suggesting that microplastics are ubiquitous in all ocean layers,” said Bridie Allan, co- Study author, at a University of Otago statement.
“A random sample of fish guts were analyzed to identify the type of plastic, with the majority turning out to be polyethylene, viscose, polypropylene and plastic additives. Polyethylene is the most commonly used plastic and also the most prevalent in oceans worldwide,” she said .
“As the fish were collected over the course of a year rather than at a single point in time, this suggests that the presence of microplastics in our southern waters is an ongoing feature.”
While a variety of microplastics have been found in fish worldwide, the New Zealand study is the first time a similar trend has been observed in the southern hemisphere.
“Research has been done around the world on microplastics in fish, with results similar to my study. The Southern Hemisphere has conducted limited research on microplastic pollution in the sea, with most studies focusing on the Northern Hemisphere and around oceanic gyres,” Clere said.
Ocean gyres are large systems of circular ocean currents formed by wind patterns and forces created by the Earth’s rotation.
Microplastics are known to bioaccumulate in food chains and increasingly accumulate in the tissues of predators. This can damage the health of the animals: acc Scientific AmericanMicroplastic particles can damage organs by rubbing against organ walls, carry pollutants on their surface and cause liver damage.
“In general, seafood that is eaten whole, such as sardines, anchovies and shellfish, has a greater risk of secondary transmission from plastics,” Clear said.
“Plastics also contain a number of chemicals, some of which can be transmitted to humans through ingestion. However, very little research has been conducted to date that has addressed the risks associated with the secondary transmission of plastics and associated chemicals to humans.”
Talking to Radio New Zealand morning report Clere said: “We need to be aware of our plastic use and possible misuse and how that enters the natural environment and potentially impacts us, but in terms of consumption that’s really just a personal choice.”
Microplastics are also increasingly found in the human body. A 2022 study in the journal Environment international Microplastics found in human blood for the first time.
“It’s certainly reasonable to be concerned,” said Dick Vethaak, an ecotoxicologist at the Vrije Universiteit Amsterdam in the Netherlands and author of the blood study That Guardian. “The particles are there and are transported throughout the body.”
“We also know in general that babies and young children are more susceptible to chemicals and particles.”