Salt decomposes plastic

Microplastics are present in 90 percent of the world's table salt

A few years ago, microplastics were discovered in sea salt. However, it remained unclear how widespread the small plastic particles are in the most widely used spice in the world. As part of a new study, salt from various brands from around the world has now been examined. The result: microplastics were present in 90 percent of all samples.

The plastic parts were found in 36 of the 39 brands tested, as reported by researchers from the South Korean Incheon National University and Greenpeace East Asia. The current work used previous studies on salt to examine the geographic distribution of microplastics in table salt. The researchers also wanted to find out how this spread correlates with plastic pollution.

"The results suggest that human consumption of microplastics from marine products is closely related to plastic pollution in the region," said Seung-Kyo Kim. The professor of marine science works at Incheon National University in South Korea.

A total of table salt samples from 21 countries in Europe, North and South America, Africa and Asia were analyzed. The three samples that did not contain microplastics were from Taiwan (refined sea salt), China (refined rock salt), and France (unrefined sea salt left by the evaporation of seawater from exposure to sunlight). The corresponding study was published in "Environmental Science & Technology".

The microplastic density in salt varied significantly between the different brands, but was particularly high in the Asian salt brands. The researchers found the largest amount of microplastic in salt that was sold in Indonesia. Asia is a plastic pollution hotspot, and Indonesia - with nearly 55,000 kilometers of coastline - has the second worst plastic pollution in the world, according to a 2015 study.

Another indicator of the geographic intensity of plastic pollution is the source of the salt: the microplastic density was highest in sea salt, followed by salt from lakes and finally by rock salt.

The current study is the fifth that has been written on the subject of table salt in recent years. Previous studies have been carried out by researchers in Spain, China, and the United States, as well as by a group from France, the United Kingdom, and Malaysia.