Sceintists sampled sea, rock, and lake salt from around the globe – they found microplastics in most of it.

So here's the thing: when we nudge 13 million metric tons of plastic into the oceans every year, it's bound to come back and haunt us. And sure enough, it's doing so in the most vexing way – returning as sneaky microplastics, hiding in our beloved table salt.

Last year TreeHugger reported on research that found salt samples from 8 different countries had plastic contaminants from ocean pollution. Now, a new study has taken a broader look at the problem of plastic in table salt and concludes that it's even worse than we thought.

Laura Parker writes in National Geographic that of 39 salt brands tested, 36 had microplastics in them, according to the new study by researchers in South Korea and Greenpeace East Asia.

The new research also looks at the correlation between microplastics in table salt and how predominant it is in the environment where the salt came from. Not surprisingly, they were pretty well related.

“The findings suggest that human ingestion of microplastics via marine products is strongly related to emissions in a given region,” said Seung-Kyu Kim, a marine science professor at Incheon National University in South Korea.

The 39 samples came from 21 countries in Europe, North and South America, Africa, and Asia. They varied in density of the contaminants, but the Asian brands were especially high.

"The highest quantities of microplastics were found in salt sold in Indonesia," Parker writes. "Asia is a hot spot for plastic pollution, and Indonesia—with 34,000 miles (54,720 km) of coastline—ranked in an unrelated 2015 study as suffering the second-worst level of plastic pollution in the world."

The three salts that were free of plastic came Taiwan, China, and France.

Of the three types of salt sampled – sea, lake, and rock – sea salt won the prize for highest microplastics levels, next was lake salt and then rock salt.

The new study estimates that the average adult consumes approximately 2,000 microplastics per year through salt. Given that the particles are less than five millimeters (0.2 inches) in size and often the same color of salt, it's easy for them to infiltrate without notice. Determining the health risks of ingesting microplastics has been tricky so far and nobody has been able to come a scientific conclusion. But suffice to say, at the rates we're consuming the stuff – from our seafood to our table salt to drinking water even the dust in our homes – it can't be good. It's awful for mice, that's for sure – it can't possibly be much better for humans.

What are we going to do about this mess?

The study was published this month in the journal Environmental Science & Technology.