Following this week's revelations in the Guardian about levels of plastic contamination in tap water, new studies have shown that tiny particles have been found in sea salt in the UK, France and Spain, as well as China and now the US.
Researchers believe the majority of the contamination comes from microfibres and single-use plastics such as water bottles, items that comprise the majority of plastic waste. Up to 12.7m tonnes of plastic enters the world's oceans every year, equivalent to dumping one garbage truck of plastic per minute into the world's oceans, according to the United Nations.
"Not only are plastics pervasive in our society in terms of daily use, but they are pervasive in the environment," said Sherri Mason, a professor at the State University of New York at Fredonia, who led the latest research into plastic contamination in salt. Plastics are "ubiquitous, in the air, water, the seafood we eat, the beer we drink, the salt we use – plastics are just everywhere".
Mason collaborated with researchers at the University of Minnesota to examine microplastics in salt, beer and drinking water. Her research looked at 12 different kinds of salt (including 10 sea salts) bought from US grocery stores around the world. The Guardian received an exclusive look at the forthcoming study.
Mason found Americans could be ingesting upwards of 660 particles of plastic each year, if they follow health officials' advice to eat 2.3 grammes of salt per day. However, most Americans could be ingesting far more, as health officials believe 90% of Americans eat too much salt.
The health impact of ingesting plastic is not known. Scientists have struggled to research the impact of plastic on the human body, because they cannot find a control group of humans who have not been exposed.
"Everybody is being exposed to some degree at any given time, from gestation through death," researchers from Johns Hopkins Bloomberg School of Public Health and Arizona State University wrote in 2013. "Detectable levels of [the plastic] bisphenol A have been found in the urine of 95% of the adult population of the United States."
"There is no clear effect on human health because there are no studies on that subject," said Juan Conesa, a professor who conducted research on sea salt at the University of Alicante in Spain. "But the increase of plastics in general in the environment will also [increase exposure]," Conesa said.
TheGuardian via @JessicaGlenza