Environment

New technique reveals the plastics we consume with a plate of seafood

New technique reveals the plas...
Scientists have used an advanced technique to detect and measure plastics in seafood samples
Scientists have used an advanced technique to detect and measure plastics in seafood samples
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Scientists have used an advanced technique to detect and measure plastics in seafood samples
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Scientists have used an advanced technique to detect and measure plastics in seafood samples

While we know that huge amounts of plastic waste are generated each day, and that much of it is broken down into tiny fragments called microplastics, we don’t really know much about the risks they pose to animals and humans. With this in mind, scientists have developed a new method to detect trace amounts of plastic in tissues, and tried it out on a range of seafood to find plastic particles in all samples tested.

While we know that humans consume tiny amounts of plastics through things like bottled water or the seafood we eat, we really have no idea what effect this has on our wellbeing and what, if any, levels might be considered safe. The new technique is an early step toward addressing this, with an ability to identify and measure five different plastic types at the same time, with a high degree of sensitivity.

First, edible tissues are immersed in chemicals, which dissolves any plastics that might be present. The remaining solution is then analyzed through what’s known as pyrolysis-gas chromatography-mass spectrometry, which enables the scientists to see which plastic types are present, and in what quantities.

The research was carried out by scientists at the University of Exeter in the UK and the University of Queensland in Australia, who collected raw oysters, prawns, squid, crabs and sardines from a market. The analysis revealed plastics in all of the samples, at levels of 0.04 mg per gram of squid tissue, 0.07 mg in prawns, 0.1 mg in oysters, 0.3mg in crabs and 2.9 mg in sardines.

"Considering an average serving, a seafood eater could be exposed to approximately 0.7 mg of plastic when ingesting an average serving of oysters or squid, and up to 30 mg of plastic when eating sardines, respectively," says lead author Francisca Ribeiro. "For comparison, 30 mg is the average weight of a grain of rice. Our findings show that the amount of plastics present varies greatly among species, and differs between individuals of the same species. From the seafood species tested, sardines had the highest plastic content, which was a surprising result."

The plastic types found by the researchers come from everyday sources, such as packaging and synthetic textiles. These types of waste wash into the marine environment, where they are degraded and become tiny plastics that are nearly impossible to track. These types of advances can help scientists trace the path that they take through the environment, as well as better understand what impact they might be having on the animals and humans that consume it.

“We do not fully understand the risks to human health of ingesting plastic, but this new method will make it easier for us to find out,” says co-author Professor Tamara Galloway.

The research was published Environmental Science & Technology.

Source: University of Exeter

5 comments
Dave X
We don't need to understand the risks because whatever the risks, it can't be useful. Ingesting microplastics is not beneficial to the human body, and I don't need a scientist to tell me that.
Karmudjun
Appreciate the article Nick. Not the news that confirms environmentalists suspicions that all new products end up in the food chain. And frequently - in opposition to the statements from the manufacturers - these benign products are found to interfere with hormones, or digestion, or have untoward effects as yet elucidated. Like this world isn't on a path of self-destruction already, we now have another threat lurking on our plate. (Bad pun).
buzzclick
There is certainly a concern here about how much is too much, or if any amount at all. The other side of that coin would be that it's benign and animals and humans just pass it through. If we know that microplastics exist in the food chain, then are these sea creatures suffering in life quality? Because if they are, chances are so are we.
eMacPaul
@Dave X, we do need to understand the risks to set acceptable levels. Did you know that there's arsenic in rice, and radioactive potassium in bananas and broccoli? Unless you are going to stop eating these (and probably every kind of food, actually) because they contain trace amounts of harmful substances, we do need to study the risks.
Marco McClean
Nick, I mentioned your article to Juanita, including the scientists' surprise about sardines being the most afflicted with plastic content. Juanita said, "Do you remember that time you got me sardines from Trader Joe's and they didn't just taste horribly of plastic but they seemed like they were actually made out of some kind of plastic?" I almost remember. It was awhile ago... Oh, wait, she just sent me some pictures she took of that time. They show the sardine meat opened up with a fork to reveal it's saturated with granules and balls and weird shapes not at all belonging there. I remember now. Bleagh! The date on the photos is 20170430. They're "Trader Joe's Unsalted Sardines in Spring Water," printed on the can in red, white, and black, on a light blue background.

It's too bad. One of my earliest memories (all of them good except for one screaming nightmare about a giant malevolent telephone rushing down at me in the crib) is of sitting on my grandfather's lap, happily eating sardines on buttered soda crackers, the old kind of sardines, where there were like a dozen in a can and not just three, and they still had their little heads on.