Microplastics - tiny fragments of plastic debris smaller than five millimeters in size - are an emerging environmental concern. They have permeated the global environment, infiltrating a multitude of ecosystems and living organisms. A growing body of research is highlighting the potential hazards associated with these particles, and one area of particular concern is their presence in salt, a staple ingredient in our daily diet.
In this study, 36 out of 39 salt brands sampled worldwide had microplastics in them. Applied to a larger scale, it is possible to assume that up to 90 percent of sea salt contains microplastics. Notably, microplastic levels were found highest in sea salt, followed by lake salt and then rock salt.
How Do Microplastics End Up in Salt?
(from Horiba Scientific: Where do microplastics come from?)
Microplastics come from ordinary consumable goods including synthetic textiles, city dust, tires, road markings, marine coatings, personal care products and engineered plastic pellets. 35 percent of the world’s microplastics come from synthetic fibers (i.e. polyester, nylon, acrylic, etc.) in our clothes, and are the single greatest contributors to microplastics in the ocean. Everytime we wash these synthetic textiles in a laundry machine, the abrasion and shedding releases fibers into our water supply. The fibers are often too small for our wastewater treatment facilities to filter and are discharged, eventually making their way to our oceans.
Microplastic Pollution and Effects to Marine Life
Microplastics have also infiltrated the marine food chain, posting a potential threat to food safety and marine life. This study on zebrafish found tissue accumulation of microplastics induced intestinal inflammation, oxidative stress, liver toxicity, and disturbed lipid and energy metabolism.
In laboratory animals, evidence suggests that microplastics can cross the gut membrane, enter into lymphatic and system circulation, penetrate organs and cells, accumulate in tissues such as the liver and brain, and even cross the placental barrier. These studies show maternal exposure to microplastics even alters energy and lipid metabolism in offspring and subsequent generations.Microplastics in the Human Body
The problem with these plastic polymers is not only the possibility of chemical contaminants and endocrine disruption, but also how they aggregate heavy metals, industrial pollutants, and even pathogens such as viruses, bacteria and parasites.
Exposure of human cell lines to microplastic additives such as phthalates, bisphenols, and organotins cause effects that lead to oxidative stress, cytotoxicity, immunotoxicity, thyroid hormone disruption, and altered adipogenesis and energy production. As such, microplastics and their aggregated additives are suspected to contribute to the increase in the prevalence of overweight and obese populations in the past five decades, which corresponds with the paralleled increase in global plastics production.
Our Commitment at Vera Salt
Microplastics are a ubiquitous and hidden threat. These tiny particles have infiltrated our bodies, with unknown long-term effects, and scientists are still trying to uncover the potential hazards of microplastic ingestion in humans - with estimates suggesting that the average person could be consuming up 5 grams, or a credit card’s worth of plastic per week.
At Vera Salt, we believe there should be a push for further research, diligent testing in consumable goods, and more efforts to reduce plastic consumption and waste — as we recognize the health of our planet and ourselves are intertwined.References:
- Cox, K. D., Covernton, G. A., Davies, H. L., Dower, J. F., Juanes, F., & Dudas, S. E. (2019). Human Consumption of Microplastics. Environmental Science & Technology, 53(12), 7068-7074. https://pubmed.ncbi.nlm.nih.gov/31184127/
- De Wit, W., Bigaud, N., & Dalberg Advisors. (2019). No plastic in nature: Assessing plastic ingestion from nature to people. World Wildlife Fund. https://assets.wwf.org.au/image/upload/v1/website-media/resources/pub-no-plastic-in-nature-assessing-plastic-ingestion-from-nature-to-people-jun19
- Garcia, M. M., Romero, A. S., Merkley, S. D., Meyer-Hagen, J. L., Forbes, C., El Hayek, E., Sciezka, D. P., Templeton, R., Gonzalez-Estrella, J., Jin, Y., Gu, H., Benavidez, A., Hunter, R. P., Lucas, S., Herbert, G., Kim, K. J., Cui, J. Y., Gullapalli, R., In, J. G., Campen, M. J., & Castillo, E. F. (2023). In Vivo Tissue Distribution of Microplastics and Systemic Metabolomic Alterations After Gastrointestinal Exposure. BioRxiv. https://doi.org/10.1101/2023.06.02.542598
- HORIBA. (n.d.). Where do microplastics come from? https://www.horiba.com/usa/scientific/resources/science-in-action/where-do-microplastics-come-from/
- IPEN. (2018, May 7). Marine litter plastics and microplastics and their toxic chemicals components: The need for urgent preventive measures. https://ipen.org/news/marine-litter-plastics-and-microplastics-and-their-toxic-chemicals-components-need-urgent
- Kim, J.-S., Lee, H.-J., Kim, S.-K., & Kim, H.-J. (2018). Global pattern of microplastics (MPs) in commercial food-grade salts: Sea salt as an indicator of seawater MP pollution. Environmental Science & Technology, 52(21), 12819-12828. https://doi.org/10.1021/acs.est.8b04180
- Kirstein, I. V., Kirmizi, S., Wichels, A., Garin-Fernandez, A., Erler, R., Löder, M., & Gerdts, G. (2016). Dangerous hitchhikers? Evidence for potentially pathogenic Vibrio spp. on microplastic particles. Marine Environmental Research, 120, 1-8. https://www.sciencedirect.com/science/article/abs/pii/S014111361630112X
- Kurunthachalam, K., & Krishnamoorthi, V. (2021). A Review of Human Exposure to Microplastics and Insights Into Microplastics as Obesogens. Frontiers in Endocrinology, 12. https://www.frontiersin.org/articles/10.3389/fendo.2021.724989/full
- Luo, T., Zhang, Y., Wang, C., Wang, X., Zhou, J., Shen, M., Zhao, Y., Fu, Z., & Jin, Y. (2019). Maternal exposure to different sizes of polystyrene microplastics during gestation causes metabolic disorders in their offspring. Environmental Pollution, 255(Pt 1), 113122. https://pubmed.ncbi.nlm.nih.gov/31520900/
- Parker, L. (2018, October 17). Microplastics found in 90 percent of table salt. National Geographic. https://www.nationalgeographic.com/environment/article/microplastics-found-90-percent-table-salt-sea-salt
- Qiao, R., Sheng, C., Lu, Y., Zhang, Y., Ren, H., & Lemos, B. (2019). Microplastics induce intestinal inflammation, oxidative stress, and disorders of metabolome and microbiome in zebrafish. Science of The Total Environment, 662, 246-253. https://www.sciencedirect.com/science/article/abs/pii/S0048969719303006
- Yang, D., Shi, H., Li, L., Li, J., Jabeen, K., & Kolanthasamy, P. (2015). Microplastic Pollution in Table Salts from China. Environmental Science & Technology. https://www.researchgate.net/publication/283077972_Microplastic_Pollution_in_Table_Salts_from_China