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Indian sea salts are contaminated with microplastics but can be treated with sand filtration

by K. V. Venkatasubramanian, special to C&EN
September 16, 2018 | A version of this story appeared in Volume 96, Issue 37


Photo of a clear acrylic container with layers of sand and gravel.
Credit: Environ. Sci. Pollut. Res.
Researchers tested using layers of sand, fine gravel, and coarse gravel to filter microplastics from seawater. The test bed was 25 cm wide and the layers were 10 to 16 cm deep.

Indian sea salts sold by reputable domestic brands are widely contaminated with microplastics, a new study confirms. Examining eight brands of salts obtained from markets in the Mumbai region, Chandan Krishna Seth and Amritanshu Shriwastav of the Indian Institute of Technology, Bombay, found they all contained microplastic particles (Environ. Sci. Pollut. Res. 2018, DOI: 10.1007/s11356-018-3028-5). Particle counts varied per brand, ranging from 56 ± 49 to 103 ± 39 particles/kg of salt, for an average mass of 63.76 µg/kg salt. Particle materials included polyesters, poly(ethylene terephthalate), polyamide, polyethylene, and polystyrene. “Extensive dietary consumption of these Indian sea salts in multiple countries exposes a significant international population to the associated health effects of microplastic ingestion,” the researchers note. Seth and Shriwastav also experimented with removing microplastics from seawater using a simple bed of sand, fine gravel, and coarse gravel. One pass through the filtration bed removed 85% of microplastic particles from seawater.


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