Over 90% of sampled salt brands globally were found to contain microplastics, with the highest number coming from salt sourced in Asia.

This is according to a new study co-designed by Kim, Seung-Kyu, Professor at Incheon National University and Greenpeace East Asia.

The study, which has been published in Environmental Science & Technology, a peer-reviewed scientific journal, analysed 39 various salt brands globally, showing that plastic contamination in sea salt was highest, followed by lake salt, then rock salt – an indicator of the levels of plastic pollution in the areas where the salt was sourced.

Only three of the salt brands studied did not contain any microplastic particles in the replicated samples.

“Recent studies have found plastics in seafood, wildlife, tap water, and now in salt,” says Awa TraorĂ©, west Africa oceans campaigner at Greenpeace Africa. “It’s clear that there is no escape from this plastic crisis, especially as it continues to leak into our waterways and oceans.

“We need to stop plastic pollution at its source and therefore call upon the accountability of big corporates in this crisis. They need to reduce their plastic footprint and take on the problem they have created.

“We also need to see the effective implementation of single use plastics ban laws in African countries and not only strong commitments from governments,” TraorĂ© says. “For the health of people and our environment, it’s incredibly important that these big corporates be pushed to go beyond recycling, start taking responsibility for their contribution to plastic pollution and begin reducing single-use plastic production.”

Building on previous studies of microplastic pollution in salt, this research is the first of its scale to look at contaminant levels of the geographical spread of sea salt, and its correlation with environmental discharge and pollution levels of plastics.

Assuming intake of 10 grams per day of salt, the average adult consumer could ingest approximately 2 000 microplastics each year through salt alone, as the study suggests. Even after discounting the highly contaminated Indonesian salt sample from this study, the average adult could still be consuming many hundreds of microplastics each year.

“The findings suggest that human ingestion of microplastics via marine products is strongly related to plastic emissions in a given region,” says Professor Kim, Seung-Kyu,. “In order to limit our exposure to microplastics, preventative measures are required, such as controlling the environmental discharge of mismanaged plastics and more importantly, reducing plastic waste.”