Marine life, as we know it, is suffering irreparable damage from the chemical pollution of the waters and the millions of tons of mismanaged waste dumped in the oceans each year. A new study of five different kinds of seafood revealed traces of plastic in every sample tested. The study led by the University of Exeter and the University of Queensland, researchers bought raw samples of popular seafood from a market in Australia, including 10 oysters, 10 farmed tiger prawns, 10 wild squid, five wild blue crab and 10 wild sardines. At least trace levels of plastic contamination were found in each, with the highest content found in sardines. The researchers used a newly developed method that identifies and measures five different plastic types simultaneously.
“Considering an average serving, a seafood eater could be exposed to approximately 0.7mg of plastic when ingesting an average serving of oysters or squid, and up to 30mg of plastic when eating sardines, respectively,” said lead author Francisca Ribeiro, a QUEX Institute PhD student. The new method is a “major step forward” towards plastic quantification techniques in seafood because it allows results to be reported in a mass unit, something wasn’t possible before, noted the University of Queensland release.
The traces of microplastics found are commonly used in plastic packaging and synthetic textiles and are frequently found in the marine litter: polystyrene, polyethene, polyvinyl chloride, polypropylene and poly(methyl methacrylate). In the new method, edible tissues are treated with chemicals to dissolve the plastics present in the samples. The resulting solution is analysed using a highly sensitive technique called Pyrolysis Gas Chromatography-Mass Spectrometry which can identify the different kinds of plastic in the sample at the same time. Studies to date show that microplastics not only enter our diet from seafood, but also from bottled water, sea salt, beer and honey, as well the dust that settles on our meals.
