Proliferation of microplastics in commercial sea salts from the world longest sea beach of Bangladesh

Abstract

Microplastics (MPs) are formed from the breakdown of larger plastics, as well as from personal care products. Despite of having high plastic pollution on the coast of the Bay of Bengal, yet no study has been conducted on the MPs contamination in commercial sea salts from Bangladesh. It is decisive to assess at which rate humans are exposed to MPs through sea salt consumption. For this purpose, we have collected 10 well-known brand packet salts and 3 poorly refined non-brand open salts from the local market of Bangladesh and determined their MPs content with microscopic and flourier transform infrared (FTIR) spectroscopic examination. The average value of MPs in the sea salts from Bangladesh (average 2676 MPs/kg) is higher compared to the studies of sea salt from different countries of the world except for Croatia and Indonesia. The high MPs numbers have been occurred mainly for the particles with a diameter <0.5 mm. Most of the MPs are fibre and fragments in shape. The polymer types identified using FTIR in the sea salt samples are polystyrene (PS), ethylene-vinyl acetate (EVA), high-density polyethylene (HDPE), nylon (polyamide 6), polyethylene terephthalate (PET). SEM images of the MPs show further weathering of those plastic particles which might be difficult to remove from salt during purification process. Based on the salt consumption rate, in Bangladesh, people can expose to MPs by consuming salt at a rate of 13088 MPs/year, which is alarming and might be a potential threat to public health.