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The presence of microplastics in commercial salts from different countries

View Article: PubMed Central - PubMed

ABSTRACT

The occurrence of microplastics (MPs) in saltwater bodies is relatively well studied, but nothing is known about their presence in most of the commercial salts that are widely consumed by humans across the globe. Here, we extracted MP-like particles larger than 149 μm from 17 salt brands originating from 8 different countries followed by the identification of their polymer composition using micro-Raman spectroscopy. Microplastics were absent in one brand while others contained between 1 to 10 MPs/Kg of salt. Out of the 72 extracted particles, 41.6% were plastic polymers, 23.6% were pigments, 5.50% were amorphous carbon, and 29.1% remained unidentified. The particle size (mean ± SD) was 515 ± 171 μm. The most common plastic polymers were polypropylene (40.0%) and polyethylene (33.3%). Fragments were the primary form of MPs (63.8%) followed by filaments (25.6%) and films (10.6%). According to our results, the low level of anthropogenic particles intake from the salts (maximum 37 particles per individual per annum) warrants negligible health impacts. However, to better understand the health risks associated with salt consumption, further development in extraction protocols are needed to isolate anthropogenic particles smaller than 149 μm.

No MeSH data available.


Chemical composition of the isolated particles.(a) Pie chart of the chemical composition of the isolated particles from all salt samples and the corresponding proportion of different (b) plastic polymers and (c) pigments.
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f2: Chemical composition of the isolated particles.(a) Pie chart of the chemical composition of the isolated particles from all salt samples and the corresponding proportion of different (b) plastic polymers and (c) pigments.

Mentions: The presence of a large quantity of white sediment in the lake salt from Malaysia (Table 1) blocked the 149 μm-pore size filter membrane. These particles were identified as calcium carbonate (CaCO3) using Raman spectroscopy. Therefore, this sample was excluded from MP analysis. A total of 72 MP-like particles were isolated from 16 salt brands. The average particle size (mean ± SD) was 515 ± 171 μm. The size of the smallest particle was 160 μm and the largest sized 980 μm. Figure 1 presents a histogram of the number of the particles sorted by size. As depicted by Fig. 2a, 30 particles (41.6%) were confirmed as plastic polymers, 17 particles (23.6%) were pigments, 21 particles (29.1%) were not identified, and 4 particles (5.50%) were non-plastic items (i.e., amorphous carbon). The major plastic polymers were PP at 40.0% of the total plastic polymers followed by PE (33.3%), polyethylene terephthalate (PET; 6.66%), polyisoprene/polystyrene (6.66%), polyacrylonitrile (10.0%), and polyamide-6 (nylon-6, NY6; 3.33%) (Fig. 2b). Particles identified as pigments were phthalocyanine (82.3%), chrome yellow (5.88%), hostasol green (5.88%), and hostaperm blue (5.88%) (Fig. 2c). The abundance of MPs per salt sample ranged from 0 per kg in the salt sample # France-F (i.e. Country of origin: France, brand F) to 10 in the salt sample # Portugal-N. Figure 3a and b are the stacked bar chart of the number of plastic polymer and pigment particles isolated from each salt brands, respectively.


The presence of microplastics in commercial salts from different countries
Chemical composition of the isolated particles.(a) Pie chart of the chemical composition of the isolated particles from all salt samples and the corresponding proportion of different (b) plastic polymers and (c) pigments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382780&req=5

f2: Chemical composition of the isolated particles.(a) Pie chart of the chemical composition of the isolated particles from all salt samples and the corresponding proportion of different (b) plastic polymers and (c) pigments.
Mentions: The presence of a large quantity of white sediment in the lake salt from Malaysia (Table 1) blocked the 149 μm-pore size filter membrane. These particles were identified as calcium carbonate (CaCO3) using Raman spectroscopy. Therefore, this sample was excluded from MP analysis. A total of 72 MP-like particles were isolated from 16 salt brands. The average particle size (mean ± SD) was 515 ± 171 μm. The size of the smallest particle was 160 μm and the largest sized 980 μm. Figure 1 presents a histogram of the number of the particles sorted by size. As depicted by Fig. 2a, 30 particles (41.6%) were confirmed as plastic polymers, 17 particles (23.6%) were pigments, 21 particles (29.1%) were not identified, and 4 particles (5.50%) were non-plastic items (i.e., amorphous carbon). The major plastic polymers were PP at 40.0% of the total plastic polymers followed by PE (33.3%), polyethylene terephthalate (PET; 6.66%), polyisoprene/polystyrene (6.66%), polyacrylonitrile (10.0%), and polyamide-6 (nylon-6, NY6; 3.33%) (Fig. 2b). Particles identified as pigments were phthalocyanine (82.3%), chrome yellow (5.88%), hostasol green (5.88%), and hostaperm blue (5.88%) (Fig. 2c). The abundance of MPs per salt sample ranged from 0 per kg in the salt sample # France-F (i.e. Country of origin: France, brand F) to 10 in the salt sample # Portugal-N. Figure 3a and b are the stacked bar chart of the number of plastic polymer and pigment particles isolated from each salt brands, respectively.

View Article: PubMed Central - PubMed

ABSTRACT

The occurrence of microplastics (MPs) in saltwater bodies is relatively well studied, but nothing is known about their presence in most of the commercial salts that are widely consumed by humans across the globe. Here, we extracted MP-like particles larger than 149 μm from 17 salt brands originating from 8 different countries followed by the identification of their polymer composition using micro-Raman spectroscopy. Microplastics were absent in one brand while others contained between 1 to 10 MPs/Kg of salt. Out of the 72 extracted particles, 41.6% were plastic polymers, 23.6% were pigments, 5.50% were amorphous carbon, and 29.1% remained unidentified. The particle size (mean ± SD) was 515 ± 171 μm. The most common plastic polymers were polypropylene (40.0%) and polyethylene (33.3%). Fragments were the primary form of MPs (63.8%) followed by filaments (25.6%) and films (10.6%). According to our results, the low level of anthropogenic particles intake from the salts (maximum 37 particles per individual per annum) warrants negligible health impacts. However, to better understand the health risks associated with salt consumption, further development in extraction protocols are needed to isolate anthropogenic particles smaller than 149 μm.

No MeSH data available.