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Over 90 Percent of Table Salts May Contain Microplastics, Study Finds

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New reports of microplastics turning up in just about everything from our bottled water to our beer pop up often to remind us just how widespread plastic pollution has become. New research now reports finding microplastics in over 90 percent of table salts, with sea salt unsurprisingly serving up the highest levels of microplastics when compared to lake and rock salts.

In a new analysis based on prior salt studies published in the peer-reviewed journal Environmental Science and Technology this month, researchers with the Incheon National University in South Korea and Greenpeace East Asia tested 39 table salt brands from across the world—including the Americas, Africa, Asia, and Europe—for evidence of microplastics, including 28 sea salt brands from six continents. Of those, 36 percent contained traces of the tiny plastics, with Asia being what it called a “hot spot of global plastic pollution.”


“Previous studies have identified microplastics (MPs) in commercial table salts but could not exactly address the origin of the MPs because of several limitations,” the study authors wrote. “The present study is based on the hypothesis that commercial sea salts can act as an indicator of MP pollution in the surrounding environment unless the MPs are filtered out during the manufacturing process.”

What they observed is that while the level of microplastics in table salts varied by brand and region, the sea salt ingested by humans can be a good indicator of the scale of microplastic pollution in the surrounding marine environments. The team found a “relatively high” density of microplastics in sea salts that originated from Asian countries and regions, supporting previous research about the levels of plastic pollution in Asia.


Speaking with National Geographic, Sherri Mason, a professor at the State University of New York in Fredonia who worked with University of Minnesota researchers on a different salt study, said that the team’s findings were interesting if not altogether surprising. She added that the new salt research “shows us that microplastics are ubiquitous. It’s not a matter of if you are buying sea salt in England, you are safe.”

Ingesting plastic probably isn’t ideal, but more research on its effects on humans is needed. As National Geographic pointed out, a recent study from researchers at the University of York in England published at Environmental Toxicology and Chemistry this week analyzed 320 global studies on microplastics and were unable to determine how microplastics impacted the natural environment due to a “mismatch” in data. It’s worth taking their findings with a proverbial grain of salt (sorry), however, as the study was funded by a beauty industry trade group, which Motherboard noted this week “arguably has the biggest stake in changing microplastic legislation.”

“Based on our analysis there is currently limited evidence to suggest microplastics are causing significant adverse impacts,” Alistair Boxall, a professor in the university’s environment and geography department and co-author of the study, said in a statement. “However, at the moment we are trying to compare apples to pears when it comes to comparing monitoring data with effects data.”

The ubiquity of microplastics in the things we ingest is becoming increasingly evident. A report by nonprofit journalism organization Orb Media published in March found microplastics in 93 percent of popular bottled water brands after testing 259 bottles from nine countries. Another study published in the Public Library of Science in April found that beer bottled in the Laurentian Great Lakes region using municipal water also contained microplastics, though the specific source of the plastic wasn’t clear.


“There’s probably various biological reasons you’d worry about plastic in your diet,” Melanie Austen, head of science at Plymouth Marine Laboratory in the UK, told Gizmodo in March. “I think there’s a lot of conjecture and not a lot of hard evidence yet.”

So while guzzling down teeny, tiny pieces of plastic with your meal doesn’t sound particularly appealing, there’s not too much research at present to indicate it’s doing a ton of harm—at least to us. Then again, if you needed a reason to cut back on salt in general, it’s never a bad idea!


[Environmental Science & Technology via National Geographic]