Plastics were not made for human consumption, and yet we consume them. Tiny remnants of these synthetic polymers are now leaking into our air, food and water, and preventing them has become an almost impossible blow.
A study of five popular seabirds, purchased from a market in Australia, shows just how common these micro-pollutants have become.
After purchasing five wild blue crabs, ten tiger shrimp, ten wild octopuses, ten inflated oysters, and ten wild sardines, researchers found traces of plastic in each sample.
“Considered as an average serving, a seater-eater could be exposed to about 0.7 milligrams of plastic when taking up an average serving of oysters or squid, and eat up to 30 mg of plastic at sardines, respectively,” explains Francisca Ribeiro, who ‘ t study of dietary research into plastic surgery at the University of Queensland, Australia.
“For comparison, 30 milligrams is the average weight of a grain of rice.”
We still do not know what, if anything, this is doing to our bodies, but there is reason to find out.
The ocean is the ultimate plastic sink in the world, and understanding the extent to which marine food web is contaminated with this pollution is part of the challenge.
After eating plastic of our own making, many marine species have been found that struggle with physical damage and oxidative stress. Some even died, such as the beach whales we found full of soup.
The risks to mammals on land are not known, and although we probably do not swallow as much plastic as these whales, we need to know how much we actually consume to know when we are in danger.
“Our findings show that the amount of plastic present varies greatly between species, and differs between individuals of the same species,” says Ribeiro.
Using a new mass spectrometry technique that scans five different types of popular plastic at the same time, researchers found squid samples from the Australian market contained the fewest traces, while sardines held the most.
Polyethylene, which is a plastic used in films and laminate, was found in the highest concentration, while polyvinyl chloride, aka PVC, was the most common, found in each sample.
This is not consistent with what other recent studies have discovered. Although it is not only seabirds that contain microplastics (they also contain sugar, salt, alcohol, and water), research has shown that this category of food accounts for most of our plastic notes.
In places where seabirds are heavily consumed, studies suggest that some people swallow at least 11,000 microplastic particles a year.
The problem is that so many of these studies use different methodologies and report results in different ways. Plus, many do not identify individual types of plastic and rely solely on visual observations.
Having a universal way to accurately test tissue samples for different types of plastic, scientists can compare the results from all over the world much more easily. This new technique resembles a promising avenue, allowing scientists to sharpen an even thinner amount of plastic with greater accuracy than before.
“We do not fully understand the risks to human health of ingesting plastic,” says marine scientist Tamara Galloway of the University of Exeter, “but this new method will make it easier for us to figure it out.”
If only it were harder to find seafood to test it out.
The study was published in Environmental Science and Technology.
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