A study examining table salts sold in China has purportedly found that many brands contain microscopic plastic particles such as polyethylene terephthalate, polyethylene and cellophane. Dongqi Yang, et al., “Microplastic Pollution in Table Salts from China,” Environmental Science & Technology, October 2015. Relying on samples obtained from Chinese supermarkets, researchers report that microplastic content was highest in sea salts at 550–681 particles per kilogram, followed by lake salts at 43–364 particles/kg and rock salts at 7–204 particles/kg.

The authors link this contamination to the pollution of coastal and estuary waters with water bottles, cellophane wrappers and the microbead exfoliates found in cosmetics. They also raise questions about the salt processing, drying and packaging process. Based on World Health Organization guidelines for salt intake, the study estimates that adults who maximize their sea salt consumption will ingest approximately 1,000 microplastic particles each year from table salt alone, in addition to the high microplastic concentrations found in mussels, fish and other seafood products.

“Due to the pollution of seawater, many contaminants have been found in sea salts, including plasticizers, such as di(2-ethylhexyl) adipate and benzyl butyl phthalate,” explain the authors. “Plastic might be the direct sources of these contaminants. However, plastics might absorb contaminants from the seawater and transfer them to the sea products. Therefore, the presence of marine microplastics in the sea salts might pose a threat to food safety.” See American Chemical Society’s Chemical & Engineering News, November 2, 2015.