A study published in April, in Nature.com Scientific Reports, examined 17 sea salt brands from eight different countries and found chemical impurities in all 17 samples. All of the brands were contaminated with microplastics and pigments associated with textile, rubber and fiberglass products. Commercial salt brands from Australia, Japan, France, Iran, Malaysia, New Zealand, Portugal, and South Africa, were examined by dissolving the salts and then filtering out any remaining solid particles. Then the researchers examined visually and by using Raman Spectroscopy, a process that identified molecules by laser light.
Also, there were 72 distinct particles found, 41.6% were determined to be plastic polymers, while another 23.6% percent were pigments. Sea Salt is typically made by evaporating off the water, which leaves only the solids behind. In 2015 a Chinese study found more than 250 plastic particles per pound of sea salt.