AsianScientist (Nov. 18, 2015) – Scientists in China have found tiny plastic bits in samples of commercial sea salt intended for human consumption. The new discovery, published in Environmental Science & Technology, adds to the list of seafood thought to be contaminated by the minuscule pieces of plastic, known as microplastics, which are showing up the world’s water bodies and accumulating in aquatic creatures, including fish and shellfish.
Microplastics are plastic particles smaller than five millimeters. They come from a variety of environmentally degrading sources, including industrial waste, personal care products and plastic litter. How such plastic waste affects aquatic life and people who consume seafood isn’t clear, but experts have raised concerns about the potential health effects.
Some lab tests have shown nano-sized plastic fragments can enter cells and cause tissue damage. With increasing reports on this issue, Professor Shi Huahong and colleagues from the East China Normal University wanted to see whether microplastics might also be in sea salt. The seasoning is made by evaporating sea water and is now a popular alternative to regular table salt, which comes from underground deposits.
The researchers tested 15 brands of sea salts, lake salts, and rock and well salts from underground deposits purchased at Chinese supermarkets. The sea salts contained the highest concentrations of microplastics from 550 to 681 particles per kilogram. Rock and well salts had the lowest amounts, ranging from 7 to 204 particles per kilogram, suggesting it is likely that the salts from dry deposits became contaminated during processing.
If adults were to consume sea salt at the recommended nutritional level for the seasoning, they could potentially ingest 1,000 microplastic particles every year from that source. For the sake of comparison, another study has estimated that many Europeans consume about 11,000 of these particles every year by eating contaminated shellfish.
The article can be found at: Yang et al. (2015) Microplastic Pollution in Table Salts from China.
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Source: The American Chemical Society; Photo: Ulbrecht Hopper/Flickr/CC.
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