A study of five popular sea foods purchased from an Australian market shows how these micro-pollutants have become ubiquitous.
After purchasing five wild blue crabs, ten farmed tiger prawns, ten wild rebels, ten farmed oysters and ten wild sardines, the researchers found plastic traces in every single specimen.
“Considering an average serving, a seafood eater can be exposed to about 0.7 milligrams of plastic, when an average serving of an oyster or squid, and up to 30 milligrams of plastic is obtained when eating sardines, respectively. “Explains Frankelca Ribeiro, who studies dietary risk. For plastics at the University of Queensland, Australia.
“For comparison, 30 milligrams is the average weight of one grain of rice.”
We still do not know what, if anything, it is doing for our bodies, but there is reason to explore it.
The ocean is the ultimate sink for plastics in the world, and understanding the extent to which the sea food web is contaminated by these pollutants is part of the challenge.
After ingesting plastics of our own making, many marine species have been found to suffer from physical damage and oxidative stress. Some have also died, such as beach whales we have filled with garbage.
Risks to land mammals are not known, and while we are probably not swallowing nearly as much plastic as these whales, we need to know how much we actually have to consume if we are in danger.
“Our findings suggest that the amount of plastic present varies greatly among species, and varies between individuals of the same species,” says Ribeiro.
Using a novel mass spectrometry technique that simultaneously scans for five different types of popular plastics, researchers found that squid samples from the Australian market had the lowest markings, while sardines held the most.
Polyethylene, a plastic used in films and laminations, was found in the highest concentrations, while polyvinyl chloride, aka PVC, was the most ubiquitous found in each sample.
This is no different from what other recent studies have discovered. While it is not just seafood that includes microplastics (including sugars, salts, alcohol, and water), research has shown that this category of food includes most of our plastic intake.
In places where seafood is heavily consumed, the study reported that some people ingest at least 11,000 microplastic particles a year.
The trouble is this, so many of these studies work in different ways and report in different ways. In addition, many do not identify individual types of plastic and rely on visual observations alone.
Having a universal way of carefully testing tissue samples for different types of plastic will allow scientists to compare results worldwide more easily. This new technology looks like a promising avenue, allowing scientists to hone in even tinier amounts of plastic with greater accuracy than before.
“We do not fully understand the risk to human health of eating plastic,” says marine scientist Tamara Galloway of the University of Exeter, but this new method will make it easier for us to find out. ”
If only it was harder to find seafood to test.
The study was published in Environmental Science and Technology.